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SMT Terms and Definitions

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    A

  • "A" Wave. Wave, "A"
  • Å. Angstrom
  • A/D Converter. Analog-To-Digital Converter
  • Absorption. The retention of moisture by a substance.
  • Accelerated Stress Test. A test to deliberately produce a failure.
  • Acceptable Quality Level (AQL). Maximum number of defects per 100 pieces that are allowable.
  • Acceptance Tests. Tests deemed necessary to determine the acceptability of products.
  • Accuracy. (1) The ability to hit the target. (2) Conformity of a measured value to the actual value of the sample.
  • Acoustic Microscopy. A nondestructive test that produces high resolution ultrasonic images, often used for inspecting component lid seals and die attach within components.
  • Acrylic. A monomeric acrylate or methacrylate (acrylic acid or a derivative thereof) cured in a polymerization reaction brought on by ultraviolet energy, heat, or a combination of the two.
  • Acrylic Resin. A thermosetting, transparent, flame resistant resin.
  • ACS. American Chemical Society
  • Activated Carbon. A water treatment medium, commonly used for de-chlorination and for reducing organic chemicals and radon from water. Activated Carbon is produced by heating carbonaceous substances (bituminous coal or cellulose-based substances such as wood or coconut shell) to 700罜 or less in the absence of air to form a carbonized char, and then activating (oxidizing) at 800 to 1000罜 with oxidizing gases such as steam and carbon dioxide to form pores, increasing the surface area of this adsorbent material. It can be in block, granulated, or powdered form.
  • Activated Rosin Flux. Flux, Rosin Activated
  • Activator. Thermally reactive compounds (such as amine hydrochlorides or various halides) that break down at elevated temperatures and enhance the ability of a flux to remove oxides and other contaminants from surfaces being joined.
  • Active Components. Electronic components such as semiconductors, transistors, diodes, etc., that can change the characteristics applied electrical signal.
  • Active Hold-Down. The process of pressing a component lead directly in contact with a bonding pad during soldering to ensure intimate contact between the lead and pad.
  • Activity. (1) Activities may consist of moving or handling materials and components, changing machine or tool settings, turning equipment on or off, etc. Poorly control of activities can create process variability and varying quality. (2) Flux Activity
  • ADC. Analog-To-Digital Converter
  • Additive Plating. Plating, Additive
  • Adhesion. The state in which two surfaces are held together by interfacial forces which may consist of valence forces or interlocking action.
  • Adhesion, Mechanical. Adhesion between surfaces in which the adhesive holds the parts together by interlocking action.
  • Adhesive. A substance capable of holding material together by surface attachment.
  • Adhesive, Anisotropic. An adhesive with a low concentration of metal particles to permit conduction in the z-axis only.
  • Adhesive, Conductive. A two part system comprised of a polymer base and a conductive filler.
  • Adhesive Failure. Failure resulting from insufficient bond between the adhesive and one or both substrates. Adhesive strips away from substrates.
  • Adhesive Specific. Adhesion between surfaces which are held together by valence forces or molecular bonding.
  • Adhesive Tensile Loading. When the acting forces are applied at right angles to the plane of the adhesive. The tensile strength of a bond is the maximum tensile load per unit area, required to break the bond expressed in pounds per square inch.
  • Adhesive, Thermoplastic melt on application. The process is reversible.
  • Adhesive, Thermoset undergo a chemical change during heating. The change is not reversible. Epoxies and acrylics are thermosets.
  • AFM. See atomic force microscope.
  • Ag. Chemical symbol for the element silver.
  • Aging. The change in the properties of a material over time and under varying conditions of humidity, temperature, pressure, etc.
  • Air Knife. (1) A mechanical air pressure amplifier. (2) A plenum with a narrow opening used develop high velocity air from a low pressure air source to (a) dry / remove liquid films from surfaces (b) control the coating of surfaces, or (c) heat or cool.
  • Algorithm. A set of rules specifying a sequence of actions taken to solve a problem.
  • Alignment Hole. Tooling Hole
  • Alloy. A substance made by melting two or materials together.
  • Alumina. A common substrate material composed of approximately 95% Al2O3.
  • Ambient Level. The values of signals and noise that exist at a test location when the device under test is not active.
  • Amorphous Phase. Non-crystalline. Most plastics are amorphous at processing temperature. Many retain this strength under normal temperatures.
  • Analog Circuit. An electrical circuit that provides a continuous relationship between its input and output.
  • Analog-To-Digital Converter (ADC or A/D converter). An electronic circuit that produces a digital output directly proportional to an analog signal input.
  • Anechoic Chamber. An enclosure especially designed with walls that absorb sound or radiation, creating an essentially free-field environment for testing.
  • Angle Of Attack. The angle between the squeegee and the stencil or screen.
  • Angstrom. A unit of length equal to one hundred-millionth (10^-8) of a centimeter, often used to specify radiation wavelengths.
  • Anion. An ion with a negative charge. An anion [such as chloride (Cl-), nitrate (NO3-), bicarbonate (HCO3-), or sulfate (SO4--)] may result from the dissociation of a salt, acid, or alkali.
  • Anion Exchange. Ion Exchange. A water conditioning process.
  • Antioxidants. Compounds that retard the rate of oxidation of a polymer.
  • Anisotropic. Exhibiting different physical properties in different directions.
  • Anisotropic Adhesive. Adhesive, Anisotropic
  • Annular Ring. The pad area that remains after a hole is drilled through the pad.
  • ANSI. American National Standards Institute
  • Antistatic Materials resist turbocharging more than ?00 volts.
  • Anti-Pad. The area of copper etched away around a via or a plated through-hole on a power or ground plane, thereby preventing an electrical connection being made to that plane.
  • AOI. Automated Optical Inspection
  • Application-Specific Integrated Circuit (ASIC). An IC device whose function is designed for a specific application(s).
  • Aperture. An opening in a stencil or screen.
  • Aperture, Chemical Etched. An opening in metal stencil created by coating the metal foil with photoresist, exposing an image both sides the resist using a phototool, and etching the foil from both sides.
  • Aperture, Electroformed. An opening in stencil formed by imaging a photoresist on a substrate and then plating the nickel foil around the resist to the desired thickness.
  • Aperture, Electropolished. An electrolytic post-process that "smooths" the walls of aperture walls to improve solder paste printing.
  • Aperture Files. Precise x-y location and shape of all apertures required on a printed circuit board.
  • Aperture, Laser Cut. An opening in a metal stencil created by using Gerberâ and aperture data to position a laser cutting head.
  • Aperture, Trapezoidal. An aperture with the board side opening 1 to 2 mils larger than the squeegee side opening.
  • API. Application Program Interface
  • Application Program Interface. The interface between the application's software and the application platform.
  • Application Software. A program that performs a specific service or solves a particular problem.
  • AQL. Acceptable Quality Level
  • Aqueous. A water soluble.
  • Aqueous Cleaning. Cleaning, Aqueous
  • Architecture. A structured set of protocols that implement the functions of the system.
  • Array. A group of components arranged on rows and columns.
  • Artwork. A phototool used to create (1) features during printed circuit board fabrication or (2) apertures on a screen or a chem-etched stencil.
  • Artwork Generation. The process of transferring the CAD circuit layout to reproducible artwork for use by stencil and printed circuit board fabricators.
  • Artwork Master. Artwork used to produce production masters.
  • ASIC. Application Specific Integrated Circuit
  • ASME. American Society of Mechanical Engineers
  • Aspect Ratio. (1) Thickness of a printed circuit board to the diameter of the smallest hole. (2) Thickness of a stencil to the width of the smallest aperture.
  • Assembler. A program that translates mnemonics into binary codes that run on a computer.
  • Assembly. A functional subdivision of a component, consisting of parts or subassemblies that perform functions necessary for the operation of the component as a whole. Examples: regulator assembly, power amplifier assembly, gyro assembly, etc.
  • AST. Accelerated Stress Testing
  • ASTM. American Society for Testing and Materials
  • Asynchronous. An action that takes place at an arbitrary time, without synchronization to a reference timer or clock.
  • ATE. Automatic (Automated) Test Equipment
  • Atm. Atmosphere pressure
  • Atomic Force Microscope (AFM). A microscope that works by bringing a fine needle right up to the surface of a semiconductor and tracing the topography of the material. AFMs are an alternative to scanning electron microscopes as a means of measuring and monitoring the widths and heights of critical dimensions on an integrated circuit die.
  • Au. Chemical symbol for the element gold.
  • Automated Optical Inspection (AOI). A mechanized visual inspection process.
  • AWG. American Wire Gage
  • Axial Lead. Lead wire extending from a component or module body along its long axis.
  • Axial Leaded Components are usually cylindrical in shape and have leads exiting from opposite ends along its long axis.
  • Azeotrope. A liquid mixture with a constant maximum or minimum boiling point lower or higher than the boiling points of its components and with the capacity to distill without change in composition.

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    B

  • B-Stage Resin. An intermediate stage in curing a thermoset resin. Prepreg
  • Back End Of The Line (BEOL). Test, assembly, and packaging of wafer manufacturing.
  • Ball Bonding. Bonding, Ball
  • Ball Grid Array (BGA) is surface mount technology IC package that provides electrical advantage of shorter signal and power paths and the mechanical advantage of greater interconnects and higher lead pitch, while decreasing package size.
  • Bare Board. An unpopulated printed circuit board.
  • Bare Die. An unpackaged integrated circuit.
  • Barrel. The cylinder formed in the drilled through hole in a printed circuit board.
  • Base Board. Base Material
  • Base Material. In printed circuit board fabrication, the insulating laminate where the conductor pattern is formed.
  • Batch. An entity that represents the production at any point in the process. A batch is a running control recipe. The material that is being produced or that has been produced by a single execution of a recipe is also considered a batch.
  • Batch Control. Consists of a sequence of one or more steps (phases) that must be performed in a defined order for a finite period of time to process finite quantities of input material to produce finished product.
  • Batch Manufacturing. Manufacturing in groups, lots or batches in which each part or finished good is identical.
  • Batch Processing. The method adopted when the required product volumes do not allow continuous production of one product on particular machines.
  • BBA. Bus Ball Array
  • Bed-Of-Nails. A test fixture, used with (automated) test equipment, made of spring loaded contact pins (Pogoâ pins) located to correspond with desired measurement points (nodes) on a printed circuit board.
  • Bend Radius. The radius at the inside of the bend at (1) the lead shoulder leading to the leg and (2) the base of the leg leading to the foot.
  • BEOL. Back End Of The Line
  • BGA. Ball Grid Array
  • Bi. Chemical symbol for the element bismuth.
  • Bifurcated Terminal. Terminal, Bifurcated
  • Binder. Materials added to pastes and adhesives to provide strength for handling purposes.
  • Binning. Classifying components by their performance at the final test. The analogy is to physically drop things into different bins.
  • Bipolar. (1) A signal that includes positive and negative values. (2) A type of semiconductor.
  • Birdcage. A defect in stranded wire where the strands in the stripped portion between the covering of an insulated conductor and a soldered connection (or an end-tinned lead) have separated from the normal lay of the strands.
  • BIST. Built-In Self Test
  • BIT. Built-In Test
  • Blind Via. Via, Blind
  • Blister. Raised areas on the surface of the laminate caused by the pressure of volatile substances entrapped within the laminate.
  • Blow Hole. A cavity in the solder surface whose opening has an irregular and jagged form, without a smooth surface.
  • Board. Printed Circuit Board
  • Board-Level (Circuitry) Repair. Repair, Board-Level (Circuitry)
  • BOD. Biological Oxygen Demand
  • Bond Strength. The force per unit area required to separate two adjacent layers of a package. The force is applied perpendicular to the surface of the package.
  • Bonding. Joining of two materials.
  • Bonding Alloy. Solder
  • Bonding, Ball. A wire bonding method that melts a sphere of gold wire, melts the sphere at the first connection point, draws a loop in the wire, and makes a wedge bond at the other connection point.
  • Bonding, Die. The attachment of an integrated circuit chip to a substrate.
  • Bonding Pad. Pad. Termination
  • Bonding, Tape. Using a metal or plastic tape material to support the carrier of a component in a gang bonding process.
  • Bonding, Thermocompression. Machines that use pressure and heat in the absence of electrical current and without an intermediate material to form wire bonds.
  • Bonding, Thermosonic. Machines that use heat (typically 150罜), ultrasonic energy, force, and time to form wire bonds.
  • Bonding, Ultrasonic. Machines that use ultrasonic energy, force, and time to form wire bonds.
  • Bonding, Wedge. A wire bonding method that can use either gold or aluminum wire. Aluminum wedge bonds are made with ultrasonic bonding machines. Gold wedge bonds are made using thermosonic bonding machines.
  • Bonding, Wire. A die connect methodology that runs either gold or aluminum wires between pads on the integrated circuit to either a lead frame or pads on a printed circuit board. Ball and wedge bonding are primary wire bonding methods, of which ball bonding is more common.
  • Boundary Scan. A functional test designed into integrated circuits.
  • Bow. A cupped variation from a known flatness of a printed circuit board.
  • Breakaway Tabs. Excess material left on printed circuit boards during fabrication to improve board handling that is removed after assembly.
  • Breakout. Poor registration between the hole and the pad on a printed circuit board to the degree that the hole is not within the area of the pad.
  • Bridging. A buildup of solder between components, conductors, and/or base substrate forming an undesired conductive path.
  • British Standards Institute (BSI). A standard setting organization.
  • BSI. British Standards Institute
  • Buffer. A solution that minimizes changes in hydrogen ion concentration that would otherwise occur as a result of a chemical reaction.
  • Built-In Self Test (BIST). Test, Built-In
  • Built-In Test (BIT). Test, Built-In
  • Bulk Components. Packaging with loose chip or MELF components that with a special feeder present the parts the pick and place head.
  • Bump. A small mound formed on the device or the substrate pads that can be used as a contact for face-down bonding. This is a method of providing connections to the terminal areas of a device.
  • Buried Via. Via, Buried
  • Burn-In. An accelerated stress test run at elevated temperature to weed-out marginal components.
  • BPA. Bus Pad Array
  • Butt Lead Package. I Lead Package.

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    C

  • C4. Controlled Collapse Chip Connection
  • C5. Controlled Collapse Chip Carrier Connection
  • C-Stage Resin. A resin in the final stage of curing.
  • CAD. Computer Aided Design
  • CAGR. Compound Annual Growth Rate
  • CAM. Computer Aided Manufacturing
  • Camera, Component. An upward looking camera used to determine part position offsets required for proper placement.
  • Camera, Fiducial. A downward looking camera in the placement head used to determine position of the printed circuit board relative to the head. Or vice versa.
  • Canadian Standards Association (CSA). A Canadian safety standard certification organization.
  • Capability. Process Capability
  • Capability Ratio. Cp
  • Capability Ratio, Centered. Cpk
  • Capacity Buy. Buying of equipment to increase manufacturing capacity, as opposed to a technology buy.
  • Capillary Action. A flow of a fluid against gravity between solid surfaces.
  • Card. Printed Circuit Board
  • Carrier Tape. Tape, Carrier
  • CASE (Tools). Computer-Aided Software Engineering.
  • Castellation. Metalized features that are recessed on the edges of a chip carrier, which are used to interconnect conducting surfaces or planes within a chip carrier or on the chip carrier.
  • Catalyst. A chemical that changes the rate of a chemical reaction.
  • Cation. A positively charged ion in an electrolyte solution, attracted to the cathode under the influence of a difference in electrical potential. Sodium ion (Na+) is a cation.
  • Cation Exchange. Ion Exchange. A water conditioning process, commonly used for water softening.
  • Cation Exchange Resin. Cation exchanger. Base exchanger. An ion exchange material possessing reverse exchange ability for cations. Sulfonated polystyrene copolymer divinylbenzene (DVB) exchange resin is used almost exclusively today in ion exchange water softeners.
  • CBGA. Ceramic Ball Grid Array
  • Chip Carrier
  • CCGA. Ceramic Column Grid Array
  • Centered Capability Ratio. Cpk
  • Centering. Correcting the actual center of a part on a nozzle after picking to the true center of the nozzle.
  • Centering, Mechanical. Repositioning a part on a nozzle after it has been picked using spring-loaded jaws that close around the part and move it to the proper position.
  • Centering, Vision. Using a camera to determine position offsets to compensate for the location of the part on the nozzle.
  • Ceramic. An inorganic, nonmetallic material, such as alumina, beryllia, steatite, or forsterite, which is fired at a high temperature. Ceramics are used in electronics as a substrate or to create component packages.
  • Ceramic Ball Grid Array (CBGA). A ball grid array (BGA) package of cofired alumina ceramic substrate allowing various lid sealing and encapsulation techniques.
  • Ceramic Column Grid Array (CCGA). A ceramic ball grid array (CBGA) with solder columns replacing the solder balls.
  • Certification. The act of verifying and documenting that personnel have completed required training and have demonstrated specified proficiency and have met other specified requirements.
  • CFC. Chlorinated Fluorocarbon (Chlorofluorocarbon)
  • CFR. Code of Federal Regulation
  • CGA. Column Grid Array
  • Chelating Agent. This agent forms a bond with the ions, such as calcium and magnesium ions and prevents precipitation of calcium and magnesium salts as hard water.
  • Chelation. The mechanism by which chemicals that would otherwise precipitate are complexed in solution with a chelating agent.
  • Chemical Etched Aperture. Aperture, Chemical Etched.
  • Chemical Etched Stencil. Aperture, Chemical Etched.
  • Chemical Vapor Deposition (CVD). Deposition of thin films (usually dielectrics/insulators) on silicon wafers by placing the wafers in a mixture of gases which react at the surface of the wafers.
  • Chem-Etched. Chemical(ly) Etched.
  • Chip. (1) Chip Component. (2) Integrated Circuit. (3) Bare die.
  • Chip Carrier. A low profile four sided (rectangular) part package, whose semiconductor chip cavity or mounting area is a large fraction of the chip size.
  • Chip Component. A SMT passive device, including resistors, capacitors, and inductors.
  • Chip On Board (COB). An unpackaged silicon die mounted directly on the printed circuit board and connected with wire bonds.
  • Chip Scale Package. A popular description is that a CSP must be no more than 120% the X and Y dimensions of the silicon die within the package. So, the CSP is a die on a carrier substrate. In order to maintain the CSP die to package ratio the CPS is generally a ball grid array. So, this description becomes fuzzy because CSP fabricators routinely shrink the die to reduce cost, but generally do not change packaging.
  • Chip Shooter. A high speed surface mount component handler and placer.
  • Chlorofluorocarbon (CFC). A chemical that was used in the electronic, chemical, and refrigeration industries.
  • CIM. Computer Integrated Manufacturing
  • Circuit. Circuitry
  • Circuit Width. Conductor Width
  • Circuitry. The configuration or design of the conductive material on the base material. This includes conductors, lands, and through connections when these connections are an integral part of the manufacturing process.
  • Circuitry-Level Repair. Repair, Board-Level (Circuitry)
  • Circumferential Separation. A crack or void in the plating extending around the entire circumference of a PTH, or in the solder fillet around the conductor, in the solder fillet around an eyelet, or at the interface between a solder fillet and a land.
  • Clamshell (Fixture). A two sided test fixture that opens like a book (clamshell) to accept the printed circuit board or assembly for testing.
  • Class XXXX Clean Room. A clean room rating system. For instance, a Class 100,000 Clean Room limits the particle count to less than 3500 particles per liter (100,000 particles per cubic foot) of a size of 0.5 micron or larger, or 25 particles per liter (700 particles per cubic foot) of a size 5.0 microns or larger.
  • CLCC. Ceramic Leaded Chip Carrier
  • Clean Room. An enclosed room employing control over particulate matter in the air with temperature, humidity, and pressure controls.
  • Cleaning. The process of removing flux residues and other contaminants from the surface of a printed circuit assembly.
  • Cleaning, Aqueous. Cleaning parts with water (e.g., tap, pure, or de-ionized) as the primary cleaning fluid.
  • Cleaning, Manual. Spot cleaning flux residues from assembly surfaces, usually using a brush and isopropyl alcohol as the cleaning agent or solvent.
  • Cleaning, Plasma. A bonding pad preparation process that uses electrically excited gas molecules to remove surface contamination.
  • Cleaning, Semiaqueous. A cleaning process using a solvent followed by a hot water rinse and drying.
  • Cleaning, Solvent. A cleaning process using chlorinated and fluorinated hydrocarbon liquids.
  • Cleaning, Ultrasonic. A cleaning process using ultrasonic energy (mechanical oscillation ) along with a chemical solvent.
  • Cleaning, Vapor Degreaser. A cleaning process where a heated solvent is condensed on the printed circuit board to be cleaned.
  • Client. A software application which communicates with another software application (the server). The server normally supplies data or functions to the client.
  • Clinched Lead. A pin through hole lead that is bent on the solder side of the printed circuit board to hold the component in place prior to soldering.
  • Contract Manufacturing (Manufacturer)
  • CMOS. Complementary Metal Oxide Semiconductor
  • CMS. Contract Manufacturing Services
  • Coating. A thin layer of conductive or dielectric material applied over components or a base material.
  • COB. Chip On Board
  • Cohesive Failure occurs when internal strength of the adhesive is not as great as the forces applied to it. Adhesive remains bonded to both substrates.
  • Coefficient of Thermal Expansion (CTE). The ratio of change in dimension per unit change in temperature.
  • Cofire. A process for forming multilayer ceramic substrates in which thick-film conductors and dielectrics are simultaneously processed by a firing cycle.
  • Cold Flow. Movement of insulation (e.g. Teflon) caused by pressure. Creep.
  • Cold-Junction Compensation. An artificial reference level that compensates for ambient temperature variations in thermocouple circuits.
  • Cold Solder Joint. Solder Joint, Cold
  • Colloid. A substance that remains suspended in a solution or fails to settle out of solution.
  • Column Grid Array (CGA). A packaging technology similar to a pin grid array, in which a device's external connections are arranged as an array of conducting pins on the base of the package. However, in the case of a column grid array, small columns of solder are attached to the conducting pads.
  • Comb Pattern. Two sets of interconnected interspaced finger-like arrays of uniformly spaced conductors. SIR testing requires comb patterns on printed circuit boards.
  • Combinational Testing. Test, Combinational
  • Compiler. A program that translates high-level-language statements into codes that a computer can execute.
  • Component. (1) A functional subdivision of a system, generally a self-contained combination of assemblies performing a function necessary for the system's operation. Examples: power supply, transmitter, gyro package, etc. (2) A part of an assembly or subassembly. A part.
  • Component Camera. Camera, Component
  • Component Hole. Plated-Through-Hole (PTH)
  • Component Lead. A wire or formed conductor extending from a component and serving as a mechanical and/or electrical connection.
  • Component-Level Repair. Repair, Component-Level
  • Component Side. Primary side
  • Composite. A resin combined with another material, such as glass fiber, to improve physical properties.
  • Computer Aided Design (CAM). A design method that uses computer generated images, rather than mechanical drawings.
  • Computer-Aided Software Engineering (CASE) Tools allow users to make changes in the way they access information from a relational data base.
  • Computer Integrated Manufacturing (CIM). Linking computer aided design data to the computer controlled assembly and test equipment used to produce the product.
  • Conductive Adhesive. Adhesive, Conductive
  • Conductive Material. Electrostatic Conductive Material
  • Conduction (Soldering). Soldering, Conduction
  • Conductor. A lead, solid or stranded, or printed wiring path serving as an electrical connection.
  • Conductor Spacing. The distance between traces on a printed circuit board.
  • Conductor, Thermal. Thermal Conductor
  • Conductor Thickness. The thickness of the conductor including all metallic coatings, excluding non-conductive protective coating.
  • Conductor Width. The observable width of a circuit or conductor at any point chosen at random. The width is measured from directly above.
  • Conformal Coating. A thin electrically nonconductive protective coating that conforms to the configuration of the covered assembly to provide environmental and mechanical protection.
  • Conformity. The ability to satisfy specified requirements.
  • Connection. An electrical termination that was soldered. A solder joint.
  • Connection, Interlayer. An electrical connection between conductive patterns in different layers of a printed circuit board. Via
  • Construction Analysis. Destructive Physical Analysis (DPA). The process of destructively disassembling, testing, and inspecting a device for the purpose of determining conformance with applicable design, process, and workmanship requirements.
  • Contact Angle. Wetting angle. The angle of wetting between a solder fillet and the pad or component lead. A small contact angle indicates good wetting, and a large angle indicates poor wetting.
  • Contact Resistance. The maximum resistance allowed between a pin and the socket contacts of a connector when assembled and in use.
  • Contaminant. An impurity or foreign substance present in a material that affects one or more properties of the material. A contaminant may be or not be ionic.
  • Control Chart. A chart for tracking a series of measurements taken over time.
  • Control System. A system to guide or manipulate various elements in order to achieve a prescribed result.
  • Convection. Transfer of energy (heat) by the circulation of a fluid or gas.
  • Conveyor. A machine that supports a printed circuit board and moves it from one location to another.
  • COO. Cost Of Ownership
  • Coplanarity. The vertical spread in the measurement of the lowest and highest contact ("out-of-line") of a package.
  • Copper Tin Intermetalic. Intermetalic, Tin Copper
  • Core Material. In printed circuit board fabrication, fully cured inner layers of a multilayer printed circuit board.
  • Core Solder. Solder, Wire/Core
  • Corrosion. The chemical reaction of a metal in contact with the air.
  • COTS. Commercial Off The Shelf
  • Coupon. A portion of a printed circuit board used for testing.
  • Court Yard. The keepout area of a surface mount component.
  • Cover Tape. Tape, Cover
  • Cp. Capability Ratio. Measurement of the width of the distribution of process measurements, compared to a desired point.
  • Cpk. Centered Capability Ratio. Measurement of the mean of process measurements, compared to a desired point.
  • Crazing. An internal condition occurring in the laminate base material in which the glass fibers are separated from the resin, caused by mechanical stress.
  • Creep. Cold Flow
  • Critical Dimension (CD). The minimum width that is allowed as part of the circuit design, on any given patterning layer.
  • Critical Path Method. A technique to determine the order in which operations must be executed to complete a project in minimum time, and determine which operations have some "float" or capacity to be rescheduled without affecting the minimum time.
  • CRT. Cathode Ray Tube
  • Crystallinity. A state of molecular structure in some polymers denoting uniformity and compactness of the molecular chains.
  • CSA. Canadian Standards Association
  • CSP. Chip Scale Package
  • CSP-C. Ceramic Chip-Scale Package
  • CSP-L. Laminate Chip-Scale Package
  • CTE. Coefficient of Thermal Expansion
  • CTE Mismatch. The difference in the CTE of two materials or components joined together. This mismatch can produce strains and stresses at joining interfaces or in attachment surfaces.
  • Cu. Chemical symbol for the element copper.
  • Cup Terminal. Terminal, Cup
  • Cure. A heat, catalyst, or pressure activated chemical reaction that changes the physical properties of a material.
  • Curing Cycle. The time-temperature profile needed to cure a thermosetting material like a bonding adhesive.
  • Curing Time. The time needed to cure a thermosetting plastic material.
  • Cycle Rate. A dry run time.
  • CVD. Chemical Vapor Deposition

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    D

  • DAC or D/A Converter. Digital-To-Analog Converter
  • DARPA. Defense Advanced Research Projects Agency
  • Data Acquisition System. Any device that acquires information from sensors using amplifiers, multiplexers, and analog to digital converters.
  • DCA. Direct Chip Attach
  • DCS. Distributed Control System
  • DDA. Direct Die Attach
  • DDE. Dynamic Data Exchange
  • Defect. Any nonconformance to specified requirements by a unit or product.
  • Definition. Degree that a produced pattern matches the master pattern.
  • Defluxing. Cleaning. Removing flux residues after a soldering operation.
  • Degradation. Destructive change in the chemical structure of a plastic reflected in its appearance or physical properties.
  • Degreasing. Cleaning. Removing wave oil and flux residues after a soldering operation.
  • Deionized (DI) Water. A pure form of water with no ionized material.
  • Delamination. A separation of the bonded layers or foils of a laminated material, such as a printed circuit board.
  • Dendrite. Metallic filaments growing by electromigration between two points.
  • Density. The weight of a material in relationship to its volume.
  • Deposition. The process of applying a material on a substrate by applying pressure through a screen or stencil.
  • Desiccant. A substance, such as calcium oxide or silica gel, with a high attraction for water and is used as a drying agent.
  • Desiccant Cabinet. A nitrogen atmosphere storage area for moisture sensitive parts.
  • Design Of Experiments (DOE). A statistical technique for determining the relationship between and relative importance of various factors controlling a process.
  • Design Rules. Allowable dimensions, keepout areas, and tolerances used in the layout and design of circuitry.
  • Desoldering. A disassembly method of removing the solder from components on a printed circuit board.
  • Detergent. A product designed to make materials, often oils and greases, soluble in water. Usually, detergents are made from synthetic surfactants.
  • Deviation. A specific authorization, granted before the fact, to depart from a particular requirement of specifications or related documents.
  • Device. Component
  • Dewetting. The condition in the solder joint in which the liquid solder has not adhered intimately with one or more the components. Characterized by an abrupt boundary between the solder and the component lead or conductor. Can be distinguished by a "rolling back" of the solder from the lead or conductor.
  • DFA. Design For Assembly
  • DFT. Design For Test
  • DI (Water). Deionized water.
  • Diazo. A type of artwork film.
  • Die. Integrated circuit chip as diced or cut from the finished wafer.
  • Die Attach. Bonding a die to its mount in its package. This is often done with a metal based glue-like silver epoxy for good conduction of heat away from the chip.
  • Die Bonding. Bonding, Die
  • Dielectric. Nonconducting material used to encapsulate circuitry and in the manufacture of capacitors and printed circuit boards.
  • Dielectric Constant. That property of a dielectric which determines the electrostatic energy per unit volume for unit potential grade.
  • Dielectric Strength. The voltage at which an insulating material can withstand before breaking down occurs, usually expressed as volts per mil.
  • DIP. Dual Inline Package
  • Diffusion. A material transport phenomena that occurs in solids, and is caused by the continual physical motion of atoms from one position to another. This results in the flow of material from regions of high concentration to regions of low concentration.
  • Digital. A type of circuit in which the signals can have only one of two possible states, a "1" or a "0".
  • Digital-To-Analog Converter (DAC or D/A Converter). A device that converts digital information into a corresponding analog voltage or current.
  • Dikes. Side Cutter
  • Direct Chip Attach (DCA). Chip-on-board technology.
  • Direct Die Attach (DDA). Direct Chip Attach
  • Direct Memory Access (DMA). The direct transfer of information between a computer's memory and a device while the computer's CPU does something else.
  • Discrete Components. Individual resistors, capacitors, diodes etc.
  • Dispense (ing). A machine or manual method of applying solder paste, adhesives, and other gels using air or mechanical pressure to force the material being dispensed through a nozzle or tip onto a substrate.
  • Dispersants. Organic and inorganic phosphates and polymers used in aqueous cleaning to assist in the removal of insoluble materials.
  • Dissipation Factor. The tangent of the loss angle of the insulating material.
  • Dissipative Material. Electrostatic Dissipative Material
  • Dissociation. The separation of an electrolyte into ions of opposite charge.
  • Distributed Control System (DCS). A real-time control system for continuous and batch process applications.
  • Distributed Processing. The physical and/or logical connectivity of hardware, software, information and load sharing.
  • Disturbed Solder Joint. Solder Joint, Disturbed
  • Divinylbenzene (DVB). A widely used cation exchange resin.
  • Document Management System. Provides storage, retrieval and manipulation of documents in a compact space.
  • DOE. Design Of Experiments
  • Double-Sided Assembly. A printed circuit assembly with components on both sides of the substrate.
  • Double Sided Reflow Soldering. Reflow Soldering, Double Sided
  • Down Force. Squeegee Pressure.
  • DMA. Direct Memory Access
  • DPA. Destructive Physical Analysis or Construction Analysis
  • DPM. Defects Per Million (opportunities)
  • DRAM. Dynamic Random Access Memory
  • Draw Bridge. Tomb Stone
  • Drill Files. Precise x-y location and sizes of all holes required on a printed circuit board.
  • Drill Wander. In printed circuit board fabrication, deviation from the target drilling location.
  • Dry Etching. Plasma Etching
  • Dry Run (ning). Operating a machine without processing. For instance, dry running a placement machine sequentially moves the head to the feeders and the component placement locations.
  • Dross. Chiefly tin oxide, but contains oxidized lead and other contaminants that form on the surface of molten solder.
  • Dross Content. A measure of the cleanliness of solder powder.
  • DSP. Digital Signal Processor
  • Dual Inline Package (DIP). A PTH package with two parallel rows of leads extending from the base of the component. Standard lead pitch is 0.100 inch.
  • Dry Film (Solder Mask). Solder Mask, Dry Film
  • Dual Gantry. A machine positioning system with two independent gantries.
  • Dual Wave Soldering. Soldering, Dual Wave
  • Dummy Component. A non-functional component package.
  • Dummy Land. A conductor on a printed circuit board that is not connected electrically to other circuitry.
  • Dummy Pad. Pad, Dummy
  • Durometer. A measure of the hardness of a non-metal.
  • DVB. Divinylbenzene
  • Dynamic Data Exchange. DDE is a communication protocol that allows Windows® programs to communicate with each other.

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    E

  • Edge Connector. The portion of the PCB used to provide external electrical connection.
  • Edge Clearance. A keepout area on the side and each ends of printed circuit boards required for board handling.
  • EDS. Energy Dispersive Spectrograph
  • EIA. Electronic Industries Association
  • EIAJ. Electronic Industries Association of Japan
  • Elastomeric. A material that at room temperature can be stretched repeatedly to at least twice its original length, and upon release of the stress, will return with force to its approximate original length. Rubber band material is elastomeric.
  • Electrochemical Migration. An unplanned electrolytic plating process. A film of polar solvent, often water, on a substrate surface provides for current flow between points with a difference in electrical potential.
  • Electrode. A conductor through which a current enters or leaves an electrolytic cell, vacuum tube, or any nonmetallic conductor.
  • Electroformed Aperture. Aperture, Electroformed
  • Electroformed Stencil. Stencil, Electroformed
  • Electroless Nickel - Immersion Gold. A coating applied during printed circuit board fabrication to protect copper features from oxidation.
  • Electroless Plating. Plating, Electroless
  • Electrolyte. Compounds that conduct an electric current by the movement of ions.
  • Electrolytic Corrosion. Corrosion by means of electrochemical action.
  • Electrolytic Plating. Plating, Electrolytic
  • Electromagnetic Compatibility (EMC). (1) The ability of electronic equipment to operate in an intended electromagnetic environment without degradation caused by interference. (2) The ability of equipment to operate in its electromagnetic environment without creating interference with other equipment.
  • Electromigration. Electrochemical Migration
  • Electroplating. Electroless Plating.
  • Electropolished Aperture. Aperture, Electropolished
  • Electropolished Stencil. Stencil, Electropolished
  • Electrostatic Conductive Material. Material with a surface resistivity of 10 ohms per square maximum.
  • Electrostatic Discharge (ESD). The transfer of a charge when the two objects have different electrostatic potentials. The potentials can be caused by either direct contact or induced by an electrostatic field. In electronic manufacturing, the employee working on a printed circuit board and a component on the same board can have different electrostatic potentials, which will damage electronic components.
  • Electrostatic Dissipative Material. Materials with a surface resistivity greater than 10^5, but less than 10^12 ohms per square.
  • Electrostatic Field. A voltage gradient between an electro-statically charged surface and another surface of a different electrostatic potential.
  • Electrostatic Insulating Material. Materials with a surface resistivity greater than 10^12 ohms per square.
  • Elevator, Tray. Feeder, Tray
  • Elongation. The fractional increase in length of a material stressed in tension.
  • Embossed Tape. Tape, Embossed
  • EMC. Electromagnetic Compatibility
  • EMI. Electromagnetic Interference
  • EMS. Electronic Manufacturing Services
  • Emulsifier. An aqueous additive used to keep soils dispersed throughout the cleaning fluid.
  • Emulsion. A material that suppliers build-up on a printing screen to block portions of the screen. The un-blocked (open) portion of the screen define the pattern for depositing solder paste on the printed circuit board.
  • Encapsulating. Potting. Enclosing an article in an envelope of adhesive.
  • Encapsulating Compound. An electrically nonconductive compound used to completely enclose and fill in voids between electrical components or parts.
  • Encoder. A precision glass or metal ruler mounted on the frame of a machine that is used to measure the location of a moveable head. Encoders can be either linear or rotary.
  • ENIG. Electroless Nickel - Immersion Gold
  • Enterprise Resource Planning (ERP). A logistical extension of MRP.
  • EPBGA. Enhanced Plastic Ball Grid Array
  • Epoxy. A polymer thermosetting resin used to bond materials.
  • Epoxy Resin. A material that forms straight chain thermoplastic and thermosetting resins. Epoxy resins have excellent mechanical properties and good dimensional stability.
  • EPROM. Electronic Programmable Read Only Memory
  • ERP. Enterprise Resource Planning
  • ESD. Electrostatic Discharge
  • ESD Sensitive. Electrical and electronic parts, assemblies and equipment that could be damaged by ESD voltages.
  • ESDS. Electrostatic Discharge Sensitive
  • Etch Factor. The ratio of etch depth to the amount the resist is undercut during etching.
  • Etching. The process of selectively removing any material not protected by a resist using an appropriate solvent or acid.
  • Ethyline Vinyl Acetate Resins (EVA). Co-polymers of the polyolefins family derived from random co-polymerization of acetate and ethylene.
  • Eutectic. An alloy with a lower melting point lower than the melting points of its components. 63% tin and 37% lead (63Sn/37Pb) solder is referred to as eutectic solder. Eutectics change directly from liquid to solid, and the reverse, with no intermediate plastic states.
  • EVA. Ethyline Vinyl Acetate Resins.
  • Event Counter. A circuit that counts the occurrences of a certain condition.
  • Excessive Solder Joint. Solder Joint, Excessive
  • Excellon® Files. Drill files
  • Excising. Cutting component leads free from the remainder of the package to prepare the component for forming or placement.
  • Expert System. Software that applies knowledge and reasoning techniques that involve rules and heuristics to solve problems normally requiring the abilities of human experts.
  • Exudation. Migration of adhesives from the interior to the surface of plastic.
  • Eyelet. A hollow tube inserted in a terminal or printed circuit board to provide mechanical support for component leads or for electrical connection.

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    F

  • Farad
  • Fab. Fabrication. A "fab" can refer to either the fabricator or the printed circuit board made by the fabricator.
  • Failure. The temporary or permanent functional impairment of a component or device caused by physical, mechanical, chemical, or electrical damage.
  • Failure Mode Effect Analysis (FMEA). A structured evaluation of the impact of a failure on product or process functionality, safety, usability, maintainability, availability, and testability.
  • Fault Tolerance. The ability to execute tasks regardless of the failure of strategic components.
  • FBGA. Fine-pitched BGA
  • FBGA flange package. Fixed body size CSP. A substrate that extends beyond the boundaries of the die. The package retains its board footprint, regardless of die size.
  • FBGA real chip size. CSP in which the package dimension is closely related to the die size. The package shrinks every time there is a die shrink.
  • FBGS. Fine-Pitch Ball Grid Array
  • FCIP. Flip Chip In Package
  • FCT. Flip Chip Technology
  • FEOL. Wafer manufacturing Front-End-Of-The-Line processing.
  • FESEM. Field Emission Scanning Electron Microscope
  • FIB. Focused Ion Beam
  • Field Emission Scanning Electron Microscope (FESEM). A conventional SEM, except that a cold field emission electron source is used, providing higher image resolution, increased signal to noise ratio, and increased depth of field.
  • File Transfer Protocol (FTP). A protocol that transfers files over the Internet.
  • "Flash" Plating. Electroless Plating
  • Flatpack. A part with two straight rows of leads (normally on 0.050 inch centers) that are parallel to the part body.
  • Fluorescence. The process by which incident electromagnetic radiation induces atomic ionization. As a result of ionization, electrons from higher level orbitals drop (cascade) to lower orbitals, and energy is released by the atom in the form of X-ray photons.
  • Feature. A conductive pattern on the printed circuit board.
  • Feeder. A machine that supplies tape and reel components in the proper orientation and sequence for picking by a pick and place head.
  • Feeder, Intelligent. A feeder with a control system intended to reduce set-up and inventory control errors.
  • Feeder, Tray. A machine that supplies tray components in the proper orientation and sequence to a pick and place head.
  • FEP. Fluorinated Ethylene Propylene
  • FIB. Focused Ion Beam
  • Fid. Fiducial
  • Fiducial. A feature of the printed circuit board used to provide a common measurement point for all steps in the assembly process.
  • Fiducial Camera. Camera, Fiducial
  • Fiducial, Global. A fiducial mark used to locate the position of all circuit features on a printed circuit board.
  • Fiducial, Local. A fiducial mark used to locate an individual component.
  • Fillet. A build-up of material between two surfaces. In reference to soldering, a fillet is the solder built-up between the component and the conductor. Ideally, the fillet is smooth and concave.
  • Film Tension. The greatest longitudinal stress a film can bear without tearing apart.
  • Fine Pitch (1) In SMD: Surface mounted components with a lead or termination pitch of 0.025 (some say 0.020) inch or less. (2) In BGA: With standard pitch is 1.27 (some say 1.0) mm, anything less requires special handling. (3) The pitch that is difficult to place (requires a cost adder) in manufacturing (assembly) practice.
  • Firmware. A program permanently recorded in ROM; it is effectively a piece of hardware that performs software functions.
  • First Pass Yield. The percent of finished assemblies not requiring rework.
  • Flat Pack. An integrated circuit package with leads on two or four sides with either gull wing or flat leads.
  • Flat Wave. Laminar Wave
  • Flex. Flexible Printed Circuit Board
  • Flexible Printed Circuit Board. A printed circuit board laminate made dielectric polymer film, adhesive, and conductive foil.
  • Flip Chip. A COB technology that has bumps attached to the silicon die, is flipped, and mounted directly to a printed circuit board.
  • Flood Bar. A device on a screen printer that drags the paste back to the starting point after the squeegee has made a stroke to prepare for the next stroke.
  • Flux. A chemically-active compound which, when heated, removes minor surface oxidation, minimizes oxidation of the basis metal, and promotes the formation of an intermetallic layer between solder and basis metal. Various flux types include: low residue, organic acid, rosin, rosin activated, rosin mildly activated.
  • Flux Activation Temperature. The temperature at which flux is active enough to remove oxides from the metals being joined.
  • Flux Activity. The ability of materials (activators) in the flux to remove corrosion and make the surface solderable.
  • Flux, Inorganic. An aqueous flux solution of inorganic acids, such as hydrochloric or phosphoric, and halides. These fluxes are very corrosive and not recommended for electronic assembly.
  • Flux, Low Residue. No-clean flux. "Leave on" flux. Low residue fluxes usually have lower solids content (less than 5%) than high-solids rosin fluxes. Their primary activator materials are weak organic acids (adipic or succinic acid). No clean residues are benign on a board surface and act as electrical insulators. These fluxes can be either solvent (usually isopropanol) borne or water borne in the case of volatile organic compound (VOC) free no clean fluxes.
  • Flux, No-clean. Flux, Low Residue
  • Flux, Organic Acid (Type OA). Water Soluble Flux. Organic acid fluxes have active ingredients such as organic hydrohalides, amines, and amides. These fluxes are water soluble since they contain no rosin. Good cleaning is critical with these flux types since their residues are corrosive and electrically conductive.
  • Flux, Resin. A flux primarily is composed of natural resins other than rosin types and/or synthetic resins.
  • Flux, Rosin (Type R). Typically, these fluxes are made up of 60% solvent and 40% solids. This flux type謘 peak capability is around 262罜 (500罠). At this temperature, rosin begins decomposing into reducing gases. Above 346罜 (650罠), the flux becomes inactive and polymerizes.
  • Flux, Rosin Activated (Type RA). Rosin activated flux typically contains 1% to 5% activators. RA flux is used in applications when RMA is not strong enough. For military purposes, RA flux use usually is limited to component tinning of sealed devices and solid wire. When warm, these fluxes can conduct electricity and can leave residues that can cause corrosion or shorting path formation between conductors.
  • Flux, Rosin Mildly Activated (Type RMA). When solder surfaces require a more active flux than rosin flux, flux manufacturers add chemical compounds called activators to the rosin. RMA flux may contain a variety of activators in amounts less than 1%. Limits are placed on their electrical and chemical properties before and after soldering
  • Flux, Water Soluble. Flux, Organic Acid
  • Fluxer. The section of a wave solder machine that applies flux to a printed circuit assembly. Foam, spray, and wave fluxers are common.
  • Fluxer, Foam. Equipment for applying flux by bringing printed circuit assemblies in contact with the surface of a foam head of flux created by bubbling flux through a porous material.
  • Fluxer, Spray. Equipment for applying flux to a printed circuit board by passing the board over a fine mist of flux created by spray nozzles or ultrasonic transducers.
  • Fluxer, Wave. Equipment for applying flux by bringing printed circuit assemblies in contact with the surface of continuously flowing and circulating flux.
  • Fluxing. Using a fluxer. Applying flux.
  • FMEA. Failure Mode Effect Analysis
  • Foam Fluxer (ing). Fluxer, Foam
  • Focused Ion Beam (FIB). A "milling machine" that uses ions. Like a SEM, a sample is put in a chamber under vacuum, beneath a column which scans a focused beam of charged particles over the sample surface. In a FIB, the charged particles are ions (typically gallium) generated by a liquid metal source. The ions collide with and sputter away atoms of the sample in the scanned region. This beam can slice into the sample with great accuracy. Like in an SEM, a detector in the chamber collects secondary species (ion or electron) for imaging. Resolution is fine enough to image ICs.
  • Foot Angle. The angle of the lead foot after lead forming relative to the surface of the bottom of the component.
  • Foot Length. The part of the component lead that contacts the bonding pad on the substrate.
  • Footprint. (1) The area occupied by a device mounted on a substrate. (2) The area a machine takes up in a production area.
  • Fourth-Generation Environment (4GE). Fourth-Generation Language
  • Fourth-Generation Language (4GL). A computer language instructing the computer at a higher-level language abstraction than traditional high-level programming languages. Any computer language that does not require traditional input/process/output logic falls into this category.
  • FPT. Fine Pitch Technology.
  • Fractured Solder Joint. Solder Joint, Fractured
  • Frame. In inspection, the total area of the picture that is scanned by a camera.
  • Frame Grabber. A device that digitizes an image and stores it in a computer's memory.
  • Frame Rate. The frequency at which an image is completely updated on a display monitor.
  • Frame Relay. A technology for transmitting data packets in high-speed bursts across a digital network.
  • Freeze (ing). Solidification of a solder joint.
  • FR-4. A relatively inexpensive glass epoxy substrate.
  • FTP. File Transfer Protocol
  • Functional Test. Test, Functional
  • Fuzzy Logic. A method used to model linguistic expressions that have non-binary truth values such as PID algorithms in process control.

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    G

  • GaAs. Gallium Arsenide
  • Gantry. A mount for moving a pick and place, inspection, or dispense head in the x-y direction on a frame.
  • Gauge R&R. A statistical measurement technique that calculates the inaccuracy of a measurement device according to gauge repeatability and gauge reproducibility.
  • Gauge Repeatability. Equipment variation. The variability of a gauge when used to make repeated measurements under carefully controlled conditions.
  • Gauge Reproducibility. Appraiser variation. A statement of gauge precision when used by different operators.
  • GelPak. A matrix tray style feeder without pockets, that consists of a tacky gel over a mesh. The components are placed in a regular array on the tray and are held in place by the tacky gel. When picking components, vacuum is applied through the bottom of the tray, pulling the gel through the mesh and releasing the die.
  • GEM. General Equipment Module
  • General Equipment Module (GEM). A protocol for communicating between production equipment.
  • Gerber® Data. Used in directing a photoplotter during printed circuit board artwork fabrication.
  • GHz. Gigahertz
  • Glass Fabric. Glass yarns woven in a specific pattern.
  • Glass Transition Temperature (Tg). The temperature when a material changes from hard, brittle, and glasslike to soft and rubbery and looses considerable mechanical strength.
  • Global Fiducial. Fiducial, Global
  • Globtop. Encapsulant
  • Gold Flash. An extremely thin layer of gold with a thickness measured on the molecular level which is either electroplated or chemically plated onto a surface.
  • Golden Board. A known good printed circuit board used for evaluating other printed circuit boards or assemblies.
  • Green Strength. The holding power of a paste or adhesive before it is set or cured.
  • Ground. A mass such as earth, a ship, or a vehicle hull, capable of supplying or accepting a large electrical charge.
  • Ground, Hard. A connection to "green wire" electrical ground either directly or through low impedance.
  • Ground Plane. A relatively large mass of metal on a printed circuit board used as an electrical ground or shield.
  • Ground, Soft. A connection to ground through an impedance sufficiently high to limit current flow to safe levels for personnel (normally 5 milliamperes). Impedance needed for a soft ground is dependent upon the voltage levels which could be contacted by personnel near the ground.
  • Gull Wing. Component leads that flare outward from the part body.

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    H

  • Halide. A compound of chlorine, bromine, or iodine, often added to flux as activators. Halides can form corrosive solutions.
  • Halide Content. The ratio of free chlorine and bromine ions to solids in a flux.
  • Haloing. Mechanically-induced fracturing or delaminating on or below the surface of the base printed circuit board material; it is usually exhibited by a light area around holes, other machined areas, or both.
  • Hard Ground. Ground, Hard
  • Hardner. The part that makes a thermosetting polymer cure.
  • HASL. Hot Air Solder Leveled
  • HASS. Highly Accelerated Stress Screening
  • HAST. Highly Accelerated Stress Testing
  • HDI. High-Density Interconnect
  • Head. An element of a pick and place machine that positions (i.e., rotates, feeds-back x-y location, and moves on z axis) nozzles to pick and place components.
  • Head, Self-Planarizing. A mechanism integrated into the head of an outer lead bonder that allows the bottom surface of the thermode blades to adjust to the plane defined by the surface of the substrate.
  • Heat Resistance. The temperature at which a bond subjected to a load fails.
  • Hermetic. The sealing of an object so it is airtight.
  • HFC. Hydrofluorocarbons
  • HFE. Hydrofluoroethers
  • Hipot. An electrical test to measure the voltage breakdown of a substrate or material.
  • High Temperature Solder. Solder, High Temperature
  • Home Plate. A five sided, two dimensional, closed shape where three equal length sides form a cube with one side removed and two additional equal length sides that form interior angles of 135? 90? and 135? A picture is worth a thousand words.
  • Hook Terminal. Terminal, Hook
  • Hot Air Solder Leveled (HASL). A printed circuit board fabrication process that applies an oxidation preventing solder coating to copper pads on the printed circuit board. Solder Leveling.
  • Hot Bar Soldering. Soldering, Hot Bar
  • Hot Tack. The ability of hot melts to have holding power even while in the liquid hot state.
  • HTTP. Hypertext Transfer Protocol
  • Hybrid. A package where integrated circuits and discrete components are attached directly to a common substrate. Connections between the components are formed on the surface of the substrate and some components such as resistors and inductors may be fabricated directly onto the substrate.
  • Hydrolysis. Decomposition of a substrate by reaction with water.
  • Hydrophilic Solvent. Polar Solvent
  • Hydrophobic Solvent. Non-Polar Solvent
  • Hydroscopic. The capacity of a material to absorb and retain moisture from the ambient air.
  • Hypertext Transfer Protocol (HTTP). The protocol that negotiates document delivery to a Web browser from a Web server.

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    I

  • I Lead Package. A SMT lead that is formed so the end of the lead touches the pad.
  • IC. Integrated Circuit
  • ICT. In-Circuit Test(ing)
  • IL. Intermetallic Layer
  • IMAPS. International Microelectronics and Packaging Society
  • Immiscible. Incapable of mixing or obtaining homogeneity.
  • Immunity. The property of a piece of equipment that enables it to reject an electrical disturbance.
  • Inclusion
  • Index Time. The time required for a feeder to advance the next component on a tape to the pickup position.
  • Inert. Inactive. Static
  • Inert Atmosphere. Replacing oxygen with a noble gas, typically nitrogen, to increase the flexibility of a soldering process.
  • Inert Gas. Noble Gas
  • Infrared. (1) Transfer of energy (heat) by radiation. (2) Transfer of long wavelength light.
  • InfraRed (IR) Reflow. Reflow Soldering, Infrared (IR)
  • Injection Molded Boards. Printed circuit boards made by molding filler-reinforced resins into a desired shape. Routing and through hole metallizations are performed by seeding and plating, or by printing. An alternative approach is to transfer mold the interconnect directly onto the injection molded cards.
  • Inner Layer. Internal Layer
  • Inorganic. Compounds without carbon.
  • Inorganic Flux. Flux, Inorganic
  • Inorganic Substrate. Substrate, Inorganic
  • Institute For Interconnecting And Packaging Electronic Circuits (IPC). A research and standard setting organization focused on fabricating and assembling printed circuit boards.
  • Insufficient Solder Joint. Solder Joint, Insufficient
  • Insulation. (1) A non-conductor used to isolate or prevent contact between conductors. (2) Electrostatic Insulating Material.
  • Integrated Circuit (IC). A microcircuit that consists of interconnected elements on a single substrate, usually silicon, to perform an electronic circuit function.
  • Integration. The state in which all aspects of plant-wide operations are tied together in a continuous loop of information.
  • Intelligent Feeder. Feeder, Intelligent
  • Interconnect. Wiring patterned in integrated circuits or printed circuit board to connect different devices together.
  • Interlayer Connection. Connection, Interlayer. Via
  • Intermetalic Layer (IL). A compound formed at the interface of two different metals.
  • Intermetalic, Tin Copper. When joining 63Sn/37Pb and other high tin alloys with copper, two intermetallic compounds are formed. On the copper side is Cu3Sn and on the solder side, the relatively rough and irregular Cu6Sn5. The total thickness of the IL is usually 0.5-0.7 苖. The intermetallic compounds of copper and tin form crystalline grains, the structure of which is determined by the length and intensity of the thermal interaction. Short reaction times form fine equiaxed grains, which promote good solderability and solder joint strength. Long reaction times result in coarse grains, and a thick IL. A thick IL gives poor solderability and poor joint strength, both in t = o shear and long-term reliability. The thickness of the IL depends on the temperature, but will continue to grow even at ambient temperatures (which on the absolute (罧) scale approaches 60% of the liquidous temperature of 63Sn/37Pb solder). This becomes important when parts or boards are solder coated or pre-tinned. During prolonged or improper storage, the IL can grow through the surface, affecting solderability.
  • Internal Layer. A conductive pattern that is contained entirely within a multilayer PCB.
  • International Organization For Standardization (ISO). An international standard setting organization based in Geneva, Switzerland.
  • Intrusive Soldering. Pin & paste
  • Invar. An alloy similar to bronze.
  • Inventory Management. The systematic determination of items and quantities to be ordered; the coordination of order release and order due dates; changes in the required quantities; and the rescheduling of planned orders.
  • In-Circuit Test (ICT). Test, In-Circuit
  • Ion. A particle formed when an electron is added to, or subtracted from, a neutral atom or group of atoms.
  • Ion Exchange. A reversible chemical process in which ions from an insoluble permanent solid medium, the "ion exchanger" (usually a resin) are exchanged for ions in a solution or fluid mixture surrounding the insoluble medium. The superficial physical structure of the ion exchanger is not affected. The direction of the exchange depends upon the selective attraction of the ion exchanger resin for the certain ions present and the concentrations of the ions in the solution.
  • Ion Implantation. The process by which dopants (i.e., phosphorus, arsenic, or boron) are introduced in exact quantities into silicon. A stream of ions of the dopants is created and then directed at a silicon wafer at a precisely controlled velocity (energy), controlling both the concentration and depth of the dopant.
  • Ionic Contaminant. An ionic, or polar compound that forms free ions when dissolved in water, making the water a more conductive path. Process residue such as flux activators, finger prints, and etching or plating salts usually contain ionic contaminants.
  • Ionograph®. A brand name for an instrument used to measure ionic contamination (residues) on a printed circuit board.
  • IPA. Isopropyl alcohol
  • IR. (1) Infrared. (2) Insulation Resistance
  • IR Reflow. InfraRed Reflow. Reflow Soldering, Infrared (IR)
  • Iron. A soldering iron is a hand soldering tool.
  • ISO. International Organization For Standardization
  • ISO 9000 The "Quality System Management Standard" that specifies the elements of a quality system.
  • ISO 14000 The "Environmental Management Standard" that specifies the elements of a environmental control system.
  • Isopropanol. Isopropyl alcohol
  • Isotropic. Having properties that have equal value in all directions.
  • ITRI. Interconnection Technology Research Institute
  • I/O. Input/Output

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  • JEDEC. Joint Electronic Device Engineering Council. The component standardization group within EIA.
  • Jelly Bean Device. An integrated circuit containing a small number of simple logic functions.
  • Joint. Solder joint. Termination
  • Jumper Wire. A wire added to a printed circuit assembly to complete a circuit that was not included in the printed circuit board.
  • J-Lead. A lead, typically on plastic packages, which is rolled under the package. A side view of the formed lead resembles the shape of the letter J.

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  • Kapton ® A brand name of a polyimide film used as an electrical insulation material with good thermal, mechanical, chemical, and electrical properties.
  • Keepouts. Areas that are kept clear of any components.
  • keV. Kilo Electron Volts
  • KGB. Known Good Die
  • Known Good Board. Golden board.
  • Known Good Die (KGD). A die tested to meet requirements.

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  • Laminar Wave. A section of a dual wave soldering machine used to solder through hole components and remove shorts on SMT components.
  • Laminate. A product made of two or more layers of materials.
  • Lamination. C-stage. A heat and pressure process used to consolidate a stack of prepregs into a solid block. The term also refers to the consolidation of a stack of laminates (with circuitry) to form a printed circuit board.
  • Land. A pad.
  • Land, Lifted. Pad, Lifted.
  • Land Pattern. A combination of conductive patterns intended for the mounting interconnection and testing of a particular component.
  • Lateral Edge. The longer side of a rectangular pad or printed circuit board.
  • Laser. Light Amplification by Stimulated Emission of Radiation
  • Laser Cut Aperture. Aperture, Laser Cut
  • Laser Cut Stencil. Stencil, Laser Cut
  • Laser Soldering. Soldering, Laser
  • Lay-Up. In printed circuit board fabrication, stacking and registering the layers of a multilayer printed circuit board.
  • LCC. Leadless Chip Carrier
  • LCCC. Leadless Ceramic Chip Carrier
  • Leaching. Dissolution of a metal coating into liquid solder. Nickel barrier under-plating prevents the over-plating (usually gold or silver) from leaching into the copper base.
  • Lead Forming. Shaping the lead into a specific shape or profile required for placement or insertion and bonding.
  • Lead Frame. A sheet metal frame containing leads and a base to which an integrated circuit is attached before packaging.
  • Lead Free Solder. An alloy of tin and another metal such as antimony, bismuth, copper, magnesium, silver, zinc, or bismuth.
  • Lead, Part. The solid conductor attached to a part.
  • Lead Pitch. Pitch
  • Lead Plating. Plating, Lead
  • Lead Spacing. Pitch. The distance between the center of adjacent leads.
  • Leaded Device. Electronic device with electrical leads extending from the body of the package.
  • Leadless Device. Electronic device without electrical leads extending from the body of the package. These packages could have solder bumps or lands located on the package.
  • Leakage Current. A current that flows through or across an insulator between two electrodes.
  • LED. Light-Emitting Diode
  • Leg Angle. The angle of the vertical portion of a lead with respect to a plane perpendicular to the plane defined by the bottom of the component.
  • Leg Length. The part of the component lead between the two bend radii. The leg length is directly related to the overall lead form height.
  • Legend. Silk screened circuit designations on a printed circuit board.
  • Lifted Land (Pad). Land, Lifted
  • LEM. Light Emission Microscope
  • Liquid Photo-Imageable. Solder Mask, Liquid Photo-Imageable
  • Liquidous. The temperature when a metal or alloy is completely liquid.
  • Lithography, Optical. A process which passes optical radiation, usually ultraviolet, through a phototool and projects the pattern onto a layer of resist coating the substrate material.
  • Lithography, X-Ray. Similar in principle to optical lithography, but capable of constructing much finer features due to the shorter wavelengths involved.
  • Local Fiducial. Fiducial, Local
  • Logic Chip. A chip which does computations, makes decisions, or makes things happen. For example, the Intel Pentium microprocessor in a computer is a logic chip and does mathematical computations, among other things.
  • Low Residue Flux. Flux, Low Residue
  • Low Temperature Solder. Solder, Low Temperature
  • lm/m2. Lumens per square meter. A measure of light intensity.
  • LPI. Liquid Photo-Imageable (solder mask)
  • LR Flux. Flux, Low Residue
  • LSI. Large-Scale-Integration (Integrated Circuit)

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  • Management Information System. Computerized network used in effectively structuring critical information in a form usable for identification of inefficiencies.
  • Manual Assembly. An electronic assembly process carried out by an operator primarily using hand tools, including a soldering iron.
  • Manufacturing Defects Analyzer (MDA). Test, Manufacturing Defects Analyzer
  • Manufacturing Execution Systems (MES). A system that, rather than focusing on measurements of material usage or process control, "centers on the product itself as it moves through the plant on the way to the customer."
  • Manufacturing Resource Planning (MRP). A software tool that enables a manufacturer to plan, allocate, and track material and financial resources for a production process.
  • Mask. A material applied to allow selective etching, plating, or protection of the surface of a printed circuit board.
  • Material Safety Data Sheet (MSDS). A US OSHA standard format that suppliers use to describe the hazards of the materials they provide for use by others.
  • Material Requirements Planning. Manufacturing Resource Planning
  • Matrix Tray. Tray, Waffle
  • Microelectronics and Computer Technology Corp.
  • Multichip Module
  • MCM-C. Ceramic MCM
  • MCM-D. Deposition MCM
  • MCM-L. Laminated MCM
  • MCM-L/D, MCM-C/D. Combination MCMs
  • MCR. Molded Carrier Ring
  • MDA. Manufacturing Defects Analyzer
  • Mean Time Between Failures (MTBF). Average time an assembly or machine is available to operate.
  • Mean Time To Repair (MTTR). Average time required to repair the various problems of an assembly or machine.
  • Measling. (1) Discrete white spots below the surface of the base material, usually caused by moisture, pressure, and/or thermally induced stress. (2) A condition existing in the base material in the form of discrete lighter spots of "crosses" below the surface of the base material, which is a separation of fibers in the glass cloth at the weave intersection.
  • Mechanical Adhesion. Adhesion, Mechanical
  • Mechanical Centering. Centering, Mechanical
  • MEK. Methyl Ethyl Keytone
  • MELF. Metal electrode leadless face is a cylindrical SMT package form used for resistors and diodes.
  • Membrane Separation. A type of noncryogenic nitrogen generator.
  • Meniscus. The curved, upper surface of a liquid that is concave when the containing walls are wetted by the liquid and convex when the containing walls are not wetted by the liquid.
  • MES. Manufacturing Execution System
  • Mesh. The size of the holes on a screen used to sort powders. Sorting sieves are dimensioned in holes per square inch.
  • Mesh Size. The number of openings per inch in a screen. For example, a 325 mesh screen has 325 openings per inch.
  • Metal Content. The percentage weight of the solder alloy powder in solder paste.
  • Metal-Core Boards. Boards built with a metallic core and an organic or inorganic insulation on either sides of the core. The core could be made of steel, stainless steel, aluminum, copper, or a laminate of metals (in most cases copper Invar copper or copper tungsten copper). The insulation of the core is done prior to metallization.
  • Metering Rolls. Successive rollers used to control the fabric to resin ratio during the impregnation of resin onto glass fabric.
  • Methyl Ethyl Keytone (MEK). An US EPA prohibited material used in printed circuit board fabrication.
  • mg. Milligram
  • mg/L. Milligram/Liter
  • MHz. Megahertz
  • Microsectioning. A destructive test showing an encapsulated cross section of a part or assembly.
  • Micro BGA® (µBGA®). A brand name for a fine pitch BGA.
  • Micro-Beam X-Ray Fluorescence (MXRF). X-Ray Fluorescence
  • Micron. Micrometer. An unit of length equal to one millionth of a meter.
  • Microvia. A design technique aimed at reducing substrate (product) size. A microvia is a via less than 150um in diameter, about a half the size of common via, and normally blind. Laser drilling make microvias at 500X the speed of mechanical drills.
  • Migration. (1) Migration of adhesives from the interior to the surface of a plastic. (2) Electrochemical Migration
  • Mil. One thousands of an inch.
  • MIS. Management Information System
  • Misalignment. Misregistration of the centerline of the component lead with respect to the centerline of the pad on the substrate.
  • Misregistration. The lack of conformity between two or more patterns or features.
  • Mixed Technology. Describes the assembly process used when pin through hole, surface mount, and other mounting technologies on the same printed circuit board.
  • MLB. Multilayer Board
  • Millimeter
  • Modification. The process revising the functional capability or performance characteristics of a product to satisfy new acceptance criteria. Modifications usually are required to incorporate design changes that can be controlled by drawings, change orders, etc.
  • Molded Carrier Ring (MCR). IC with a plastic molded body and guard ring to reduce damage to leaded surface mount packages caused by normal handling. The guard ring also acts as a common form factor for the development of automation such as test, burn in, and excise and form.
  • Mole®. A brand name for a profiler.
  • Molecular Weight. The sum of the atomic weight of all atoms in a molecule.
  • Montreal Protocol. In 1987, twenty-four countries, including the United States and members of the European Economic Community signed the Montreal Protocol to control CFC and Halon compounds, which are thought to deplete the ozone layer of the Earth.
  • Mounting Hole. (1) Plated-Through-Hole (PTH). (2) A hole used in mechanically mounting a printed circuit assembly to a housing.
  • Mouse Bite. A method of securing a breakaway tab to the printed circuit board.
  • MRP. Materials Requirements Planning
  • MRP II. Manufacturing Resource Planning
  • MSDS. Material Safety Data Sheet
  • MTBF. Mean Time Between Failures
  • MTTR. Mean Time To Repair
  • Multichip Module. A modular package with both active and passive devices in one package. Versions; MCM-L, MCM-C, and MCM-D; vary according to substrate.
  • Multilayer Printed Circuit Board. A laminate with more than two layers of copper foil.
  • Multilayer Substrate. Usually referring to cofired multilayer ceramic substrates.
  • MXRF. Micro-Beam X-Ray Fluorescence

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  • NaCl. Sodium Chloride
  • Nailheading. In printed circuit board fabrication, the flaring of internal connections.
  • Nd:YAG. Neodymium glass yttrium aluminum garnet (laser)
  • Needle. A dispensing tip.
  • Negative Resist. Resist, Negative
  • Net List. A list to groups of two or more points in a circuit design that are electrically common.
  • Neutralizer. An alkaline chemical added to water to improve its ability to dissolve organic acid flux residues.
  • nF. nanoFarad
  • Ni. Chemical symbol for the element nickel.
  • Nick. A cut or notch on a conductor or insulator.
  • Nickel Over Gold. Generally, Electroless Nickel - Immersion Gold
  • NIST. National Institute of Standards and Technology
  • Nitto Tape. Tape that sliced silicon wafers are placed on prior to dicing.
  • Noble Gas. Helium, neon, argon, krypton, xenon, and sometimes radon.
  • Noble Metal. Metals; such as gold, silver, and platinum; which are extremely inactive and are unaffected by air, heat, moisture, and most solvents.
  • Node. An electrical connection of two or more components on a printed circuit board.
  • Non-Activated. A natural or synthetic resin flux without activators.
  • Non-Ionic. Non-Polar
  • Non-Ionic Contaminant. A substance that neither forms free ions, nor increases the conductivity of water.
  • Non-Polar. A substance does not ionize in water.
  • Non-Polar Solvent. A solvent that is not electrically conductive and will dissolve non-polar compounds such as hydrocarbons and resins.
  • Non-Solder Mask Defined (NSMD) Pads. Pad, Non-Solder Mask defined
  • Nozzle. (1) A tool selected to interface between a pick and place head and each particular part being placed. (2) Tip. A tool used in dispensing adhesives.
  • No-Clean Flux. Flux, No-Clean.
  • NSMD (Pads). Non-Solder Mask Defined

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  • OA Flux. Flux, Organic Acid. A water soluble flux.
  • Object-Oriented Programming. Programming based on a package of information and descriptions of procedures that communicate by passing messages.
  • ODBC. Open Database Connectivity
  • ODP. Ozone Depletion Potential
  • Off Contact (Printing). Printing with a separation between the screen or stencil and the substrate.
  • Off-Gassing. Out-Gassing
  • Omegameter®. A brand name for an instrument used to measure ionic contamination (residues) on a printed circuit board.
  • OMPAC. Over Molded Plastic Array Carrier
  • On Contact (Printing). Printing with the screen or stencil touching the substrate.
  • OOP. Object-Oriented Programming
  • Open. A loss of electrical continuity caused by (1) a break in a trace path on a printed circuit board or (2) solder failing to bridge the gap between lead termination and the pad.
  • Open Database Connectivity (ODBC). A database connectivity standard written and defined by Microsoft that allows an application to interact with any database that supports the ODBC standard.
  • Open Systems (OS). An approach to computing that allows the interconnectability of systems based on compliance with established standards.
  • Operations. A series of processes required to provide product or services meeting certain requirements. Printed circuit board fabrication is an operation.
  • Operator Interface. A physical link between the human operator and a computer system, typically consisting of a graphical representation.
  • Optical Lithography. Lithography, Optical
  • Organic. Materials based on carbon compounds. All life forms are organic. Organic fluxes are primarily composed of organic materials other than rosin or resin.
  • Organic Resist. Resist, Organic
  • Organic Solder Preservative (Protectant) (OSP). (i.e., Entek, Imidazole) A coating applied during printed circuit board fabrication to protect copper features from oxidation.
  • Organic Solvent. A solvent for organic materials, such as organic resists.
  • Organic Substrate. Substrate, Organic
  • OSHA. Occupational Safety and Health Administration
  • Osmosis. The natural tendency for water to spontaneously pass through a semipermeable membrane separating two solutions of different concentrations (strengths). The water will naturally pass from the weaker (less concentrated) solution to the stronger (more concentrated) solution of a dissolved substance.
  • OSP. Organic Solder Preservative (Protectant)
  • Out-Gassing. The release of volatile parts from a substance when placed in a vacuum environment.
  • Overheated (Solder) Joint. Solder Joint, Overheated
  • Over Molded Plastic Array Carrier (OMPAC). A brand name for plastic ball grid array.
  • Oxidation. Tarnish. The absorption of oxygen into the surface of some metals. Oxygen "burns" or oxidizes all material with which it comes in contact. Oxides are thermal insulators and resist solder wetting.
  • Oxide Content. The amount of oxides present on the surface of solder powder.
  • Ozone Depletion Potential (ODP). A relative index indicating the extent to which a chemical product may cause ozone depletion.

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  • Pa. Pascal
  • Packaging Density. The number of components, interconnections, and mechanical devices per unit volume.
  • Pad. Land. A portion of a conductive pattern used as a termination area. Metal surrounding a hole on a printed circuit board.
  • Pad, Dummy. A pad in excess of component interconnection requirements.
  • Pad, Lifted. A pad that has lifted or separated from the base material, whether or not any resin is lifted with the pad.
  • Pad, Non-Solder Mask Defined. Pads with spacing that does not allow solder (usually bumps) on the pads to contact the adjacent solder mask.
  • Pad, Solder Mask Defined. Pads with spacing that allows solder (usually bumps) on the pads to contact the adjacent solder mask.
  • Pad, Test. A 0.040 inch square pad on the surface of a printed circuit board, used to make electrical contact with a circuit node for testing purposes.
  • Pallets (Solder). A tool for positioning a printed circuit board during a process. Typically, pallets are used during wave soldering and flex and PCMCIA processing.
  • Panel. An array of, usually identical, separate circuits fabricated on a single substrate.
  • Panelized. Panel
  • Part. An element of an assembly, or subassembly that is not normally subject to further subdivision or disassembly without destruction of designed use. Examples are: Printed wiring board, resistor, integrated circuit.
  • Pascal. A unit of pressure equal to one newton per square meter.
  • Passive Hold-Down. Holding the component lead in contact with the bonding pad by pressing on the body of the component during the soldering process to ensure intimate contact between the lead and bonding pad. Intimate contact is important for proper heat transfer through the lead to reflow the solder. This is commonly used in laser and hot gas soldering.
  • Paste. Solder Paste
  • Paste In Hole. Pin & Paste
  • Pb. Chemical symbol for the element lead.
  • PBGA. Plastic Ball Grid Array
  • PCA. Printed Circuit Assembly
  • PCB. Printed Circuit Board
  • PCMCIA. Personal Computer Memory Card Industry Association
  • Peel Back. In wave soldering, when the solder of the wave breaks away from the printed circuit board and returns to the wave.
  • Peel Back Force. The force required to remove the mylar cover tape on a tape and reel carrier.
  • Peel Strength. A test of the adhesion between the lead and the bonding pad after it has been soldered. It is determined by peeling the component lead off the bonding pad using special fixturing on a pull tester.
  • Peel-Away Speed. Stencil, Peel-Away Speed.
  • Penetration. The entering of an adhesive into a substrate.
  • Perforated Terminal. Terminal, Pierced (Perforated)
  • Personal Computer Memory Card Industry Association (PCMCIA). A trade organization formed to promote interchangeability of cards among a variety of computer products.
  • pF. picoFarad
  • PFMEA. Process Failure Mode Effect Analysis
  • PGA. Pin Grid Array
  • pH. A measure of alkalinity and/or acidity of a liquid.
  • Photolithography. The photographic process used to transfer circuit patterns onto a semiconductor wafer. This is done by projecting light through a patterned reticle, onto a silicon wafer covered with a photoresist.
  • Photoplotting. Lithography. A method of creating artwork from computer files.
  • Photoresist. Resist. A light sensitive material, liquid or a laminated dry film, which when selectively exposed to light, masks off areas of the design that can be etched away.
  • Phototool. A photographic material used to produce a circuit design pattern on a substrate. Artwork.
  • Physical Vapor Deposition (PVD). Deposition of thin films by physical means as opposed to chemical (like chemical vapor deposition). This is most often used for deposition of metals. The most common form of PVD is sputtering.
  • PID. (1) Photo-Imageable Dielectric. (2) Proportional Integral Derivative (Controller).
  • Pick And Place (P&P). An assembly operation where a machine that orients and places components on their pads on a substrate prior to soldering.
  • Pick And Place Head. Head
  • Pierced Terminal. Terminal, Pierced (Perforated)
  • Pin Grid Array (PGA). A PTH package with a large array of leads protruding perpendicular to one side of a component package.
  • Pin & Paste. Using SMT processes to solder through hole parts.
  • Pinhole. (1) Soldering: A solder connection with a small hole penetrating from the surface of the solder to a void of indeterminate size within the solder connection. (2) Printing: A void that receives no ink, paste, or gel during printing.
  • Pink Ring. In fabrication, a cosmetic defect in which a pink area is seen on an internal copper feature surrounding a plated hole. This appearance is caused by the presence of clean copper, free of the copper oxide coating used an adhesion promoter between internal copper feature and prepreg resin.
  • Pin-Through-Hole (PTH). A manufacturing technology, where the slender wire leads of components are inserted through the holes of the printed circuit board.
  • Pips. Location pegs on components, such as connectors and sockets, used for manual placement and for automatic placement when precise location of the part is required.
  • Pit. A relatively small recess in the solder surface, the bottom of which is visible from all angles of vision.
  • Pitch. (1) The center-to-center spacing between the leads of a component. (2) Distance between pockets on a carrier tape. Pitch varies according to tape width and components packed on the tape. (3) The center to center distance of two adjacent sprocket holes.
  • Placement. The manual, semiautomatic, or automatic location of a component, device, or chip at its intended position.
  • Placement Head. Head
  • Planarity. Warpage. Substrate surface flatness.
  • Plasma. A gaseous state in which the atoms or molecules are dissociated to form ions. In semiconductor processing, plasmas are used for etching and thin film deposition. In everyday life, plasmas are used to give light - in fluorescent light bulbs, neon lamps, and blue-light insect "zappers."
  • Plasma Cleaning. Cleaning, Plasma
  • Plasma Etching. Dry Etching. Using a plasma to etch a semiconductor layer. The plasma contains highly excited molecules (reactive ions) which easily react chemically. There is also a physical bombardment mechanism in that the ions are accelerated towards the wafer with an electric field.
  • Plastic Ball Grid Array (PBGA). A Ball Grid Array (BGA) package of high Tg material substrate and encapsulated with either a plastic overmold or globtop. An array of eutectic (63Sn/37Pb) 0.77 mm diameter balls provide the interconnection to the printed circuit board. These balls reflow during package and printed circuit board assembly and provide a 50 mm gap or standoff between the chip carrier and the glass epoxy board.
  • Plastic Leaded Chip Carriers (PLCC). A SMT package with 50 mil spaced J-leads on all four sides that have the same dimensions.
  • Plastic Range. The temperature range of a molten metal when the metal is neither solid nor liquid.
  • Plated-Through-Hole (PTH). A plated-through hole is one formed by a deposition of metal on the inside surface of a through-hole. Also known as a supported hole. The configuration is used to provide additional mechanical strength to the soldered termination or to provide an electrical interconnection on a multilayer printed circuit board.
  • Plating, Additive. A process in which the conductive, resistive, and insulating materials are successively plated to define traces, pads, and elements.
  • Plating, Electroless. Plating as the result of chemical action (without any external electric current).
  • Plating, Electrolytic. Plating deposited by application of electrical current.
  • Plating, Lead. The metal coating on a component lead. Common lead plating materials are pure tin (Sn), pure gold (Au), and eutectic tin/lead solder (63%Sn/37% Pb).
  • Plating, Tin Lead. In printed circuit board fabrication, an electroless plating process that coats exposed areas of copper on a circuit board with a layer of tin lead alloy to prevent the copper from oxidizing.
  • PLC. Programmable Logic Controller
  • PLCC. Plastic Leaded Chip Carriers
  • PLD. Programmable Logic Device
  • Plowing. In printed circuit board fabrication, the furrows in the walls of a drilled hole.
  • Plug (ing). A printed circuit board fabrication process that fills vias to prevent heat conduction and chemical transport through the via and to allow vacuum hold-down during automated testing.
  • Pogo®. A brand name for a spring loaded test probe.
  • Poise. A centimeter-gram-second unit of viscosity.
  • Polar Solvent. A solvent that can dissolve polar compounds, such as inorganic salts, but cannot dissolve non-polar compounds, such as resins and hydrocarbons.
  • Polyester Resin. A polymer in which the structural units are linked by ester grouping.
  • Polyimides. Thermosetting ring chain polymers characterized by -NH group, used as a dielectric.
  • Polyimide Resin. A nonconductive polymer in which the structural units are linked by amide grouping.
  • Polymer. (1) A chemical compound or mixture of compounds formed by polymerization. (2) Compounds of very high molecular weights that are made up of a large number of simple molecules which have reacted with one another.
  • Polymerization. A chemical reaction in which two or more small molecules continue to form larger molecules that contain repeating structural units of the original molecules.
  • Polymerized Rosin. Rosin that has reacted with itself during the course of a soldering operation.
  • Popcorning. When moisture held with a plastic part vaporizes and the pressure cause cracks in the part.
  • Porous Solder Joint. Solder Joint, Porous
  • Portability. The ability to use and migrate software across different platforms.
  • Positive Resist. Resist, Positive
  • Potato Chip (ping). When a printed circuit board a warps or curls after it has been reflowed or wave soldered and resembles a potato chip
  • Potlife. Time a liquid resin remains workable after catalysts, hardners, etc are added.
  • Potting. Encapsulating
  • Potting Compound. An electrically nonconductive compound used to partially encapsulate or for a filler between parts, conductors, or assemblies.
  • PPM. Parts per million
  • PQFP. Plastic Quad Flat Package
  • Preform (Solder). Solder Preform
  • Preflow. Soak. The portion of a reflow profile after preheat and before the reflow spike occurs. During this time, the temperature of the metals being joined is allowed to equalize.
  • Pregel. In fabrication, small white spots just below the surface of the laminate. This can be caused by premature curing of the resin during the lamination process.
  • Preheat. Heating from ambient at a predetermined rate to avoid thermal shock.
  • Prepreg. Pre-impregnated materials are a combination of fiber and resin to create a material that is stronger than either of its constituents alone.
  • Primary Side. The side of the printed circuit board that contains the most or more complex components.
  • Print Head. The assembly on a stencil printer that holds the squeegee in place.
  • Printed Circuit Assembly (PCA). The bare printed circuit board with components and associated hardware and materials.
  • Printed Circuit Board (PCB). A pattern of conductors printed (screened) onto the surface of an insulating base to provide interconnection for parts.
  • Printed Wiring Assembly (PWA). Printed Circuit Assembly
  • Printed Wiring Board (PWB). Printed Circuit Board
  • Pressure Swing Adsorption. A type of noncryogenic nitrogen generator.
  • Probe. (1) A rigid, pointed, metallic, wire-shaped device used for making electrical contact to a circuit pad for electrical test purposes. (2) A metal scribe.
  • Process. Method. Procedure. A process may be a single method or procedure, or may be made up of sub processes and activities. Wave soldering is a process.
  • Process Capability. Competence. A measure of the process variation about a defined target value. Cp and Cpk are common process characterization indexes.
  • Process Connected Device. (1) Programmable Logic Controller. (2) Distributed Control System
  • Process Control. Automatic monitoring and control of a process by an instrument or system configured or programmed to respond appropriately to process feedback.
  • Process Failure Mode Effect Analysis (PFEMA). FEMA applied to production processes.
  • Process Management prevents defects by fulfilling individual responsibilities instead of reacting to defects as the result of not fulfilling them. The goal of process management is consistent product quality.
  • Process Simulation. Use of a mathematical model by a computer program to implement different process design scenarios with real-time feedback.
  • Production Control. Systematic planning, coordination and direction of all manufacturing activities to ensure that products are made on time, of adequate quality and at reasonable cost.
  • Production Master. In printed circuit board fabrication, a 1:1 scale pattern of the features to be produced on a layer of the board.
  • Profile. The relationship of time versus temperature during a soldering process.
  • Profiler. A tool to aid in measuring and recording thermal profiles of soldering processes.
  • Programmable Logic Controller (PLC). A control device. Logic (programs) contained in the PLC read or write to the inputs or outputs of the field devices.
  • Proportional Integral Derivative (Controller) (PID). The most commonly used algorithm in continuous process control applications. Where part of the control output is proportional to the (a) difference between the measured value and the set point, (b) the time integrated difference between the measured value and the set point, and (c) the time based derivative (the rate of change) between the measured value and the set point.
  • Protected Area. An area which is constructed and equipped with the necessary ESD-protective materials and equipment to limit ESD voltage below the sensitivity level of ESDS items handled therein.
  • Protocol. An agreed set of rules to allow data to be transferred among systems.
  • PSA. Pressure Swing Adsorption
  • PTH. Plated Through Hole or Pin Through Hole
  • Pull Strength. A measure of the quality of a solder joint formed between a component lead and a bonding pad on a substrate.
  • PVD. Physical Vapor Deposition
  • PWA. Printed Wiring Assembly
  • PWB. Printed Wiring Board
  • P&P. Pick and place (machine)

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    Q

  • QFN. Quad Flat-Pack No-lead (EIA) package
  • QFP. Quad Flat Pack
  • QFP-N. Quad Flat-Pack No-lead (JEDEC) package
  • Quality. Conformance to clearly specified, understood, and accepted customer contract requirements.

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    R

  • RA Flux. Flux, Rosin Activated
  • Radial Lead. Lead wire extending from a component or module body along its latitudinal axis.
  • Radial Lead Components have all of its leads exiting from a common side of the body. The actual body type is variable with two common types being dipped capacitors and transistor "cans".
  • Radial Split. A crack or other separation in the flange of an eyelet or other circular connector, which extends outward from the center. Such cracking is usually the result of swaging or other setting process as the item is embraced in a printed circuit board.
  • Radio-Frequency Interference (RFI). High-frequency interference with radio reception.
  • RAM. Random Access Memory
  • Real-Time System. Use of precise timing in controlling an event typically consisting of multiple changing variables.
  • Recipe. The necessary set of information that uniquely defines the production requirements for a specific product.
  • Reflow Soldering. A heat radiation or conduction soldering process that brings printed circuit assemblies into contact with heated air to melt solder. Solder reflow is completed in several stages or zones of different temperature. First, the heated air increases board and component temperature, then, activates the flux, and reflows the solder "printed" on the board surface, onto which components have been attached. Upon melting in the highest temperature zone, the solder wets all termination areas and, after cooling, makes the solder joint. IR, conduction, and vapor phase are common reflow soldering technologies.
  • Reflow Soldering, Conduction. A conduction reflow soldering machine that uses moving hot air or inert gas (nitrogen) to envelope the entire printed circuit assembly.
  • Reflow Soldering, Double Sided. Reflow soldering of components on both sides of a printed circuit assembly.
  • Reflow Soldering, Infrared (IR). An IR reflow soldering machine that uses heat radiation to warm the entire printed circuit assembly.
  • Reflow Soldering, Vapor Phase. Vapor Phase Soldering
  • Registration. The degree that a pad conforms with the position of another pad on a printed circuit board.
  • Relational Database. Management system software that configures usually large volumes of data in table-like structures called relations.
  • Reliability. The continued conformance of a device or system to a specification over an extended period of time.
  • Repair. Operations performed on a nonconforming article to place it in usable condition. Repair is distinguished from rework in that alternate processes rather than reprocessing are employed.
  • Repair, Board-Level (Circuitry). A process where the printed circuit board must be repaired in addition to the possible removal and replacement of parts. This may include fixing a damaged land, trace or via. It is most often carried out using manual techniques.
  • Repair, Component-Level. A process for removing defective components and replacing them with working components. It is typically carried out using manual or semiautomated techniques.
  • Repeatability. Precision. The ability to produce consistent results. Gauge Repeatability
  • Reproducibility. The ability to obtain consistent results when repeating a measurement or operation at different times and/or with different operators and/or using different instruments/tools of the same type. Gauge Reproducibility
  • Residue. A visual or measurable process contamination.
  • Resin. (1) In soldering: a chemically synthesized rosin. (2) In water processing: an ion exchange product, usually organic polymer beads used in softening and other ion exchange processes to remove dissolved salts from water. (3) In adhesives: an organic polymer which, when mixed with a curing agent, crosslinks to form a thermosetting plastic.
  • Resin Bead. In water processing, a spherical shaped particle of ion exchange resin products, as compared to the irregular shaped particles of most other granular media products.
  • Resist. Photoresist.
  • Resist, Negative. A process that shines ultraviolet radiation through a phototool onto a resist and causes the resist to be cured where the light shines. The uncured areas are then removed using an appropriate solvent.
  • Resist, Organic. A material which is used to coat a substrate and is then selectively cured to form an impervious layer.
  • Resist, Positive. A process similar to a negative resist, but where the resist is degraded where the light shines. The degraded areas are then removed using an appropriate solvent.
  • Resistance. The property of a material to oppose the flow of current.
  • Resistance (Soldering). Soldering, Resistance
  • Resistivity. The ability of a material to resist passage of electrical current either through its bulk or surface.
  • Resistivity of Solvent Extract (ROSE). A contamination measurement technique.
  • Reverse Osmosis (RO). A membrane procedure which separates ionic species from aqueous solutions to produce water of extremely high purity. Applied pressure forces H+ and OH ions across a membrane that does not allow for passage of other ions. The purity of the water can be measured with a conductance meter.
  • Resolution. The smallest division to which a measurement can be determined.
  • Reticle. Mask. Photomask. This is a glass plate with chrome on one side in which a pattern is etched. The pattern is transferred to the wafer by shining light through the reticle. A typical semiconductor circuit will need between 12 and 25 masking layers.
  • Revolver Head. Turret Head
  • Rework. The reprocessing of an article or material to make it conform to drawings, specifications, and purchase order.
  • RF. Radio Frequency
  • RFI. Radio Frequency Interference
  • RH. Relative Humidity
  • Rheology. The science of viscous materials and their flow properties.
  • Rigid Flex. A fabrication construction that combines a standard printed circuit board (rigid) with flexible printed circuit.
  • RMA Flux. Flux, Rosin Mildly Activated
  • RMS. Root Mean Squared
  • RO. Reverse Osmosis
  • Robber Pad. Scavenge Pad
  • Rosin. A hard, natural resin, consisting of abietic acid and pimaric acids and their isomers, some fatty acids, and terepene hydrocarbons. Rosin is extracted from pine tree stumps. It謘 an organic material distilled from oleoresin in pine tree sap.
  • Rosin, Water-White. Purified rosin used to manufacture rosin based flux. Abietic and pimaric acids are the primary active ingredients in rosin type flux. At room temperature, rosin is a solid, chemically inactive, an insulator, and soluble in solvents, but not in water. Rosin melts at about 72罜 (160罠) and the organic acids become active at around 108罜 (225罠).
  • Rosin Solder Joint. Solder Joint, Rosin
  • ROSE. Resistivity of Solvent Extract
  • Router. (1) In CAD: A computer program that determines the paths between interconnecting points. (2) In printed circuit board fabrication and assembly: A printed circuit board fabrication machine that grinds-away portions of the laminate.
  • RSA. Rosin Super Activated (flux), not to be confused with Rosin Slightly Activated (flux).
  • Rule-Based System. System written in the form of simple if-then or condition-action rules.

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    S

  • SAM. Scanning Acoustic Microscope (or surface acoustic microscope)
  • Saponifier. Alkaline chemicals, added to water, that convert rosin/resin flux residues in the water to soluble soaps.
  • SBGA. Super Ball Grid Array
  • Scanning Acoustic Microscopy (SAM). Acoustic Microscopy
  • Scanning Electron Microscope (SEM). A microscope that uses electrons rather than light to form an image. The advantages of a SEM over a light microscope are: (a) a large depth of field, which allows a large amount of the sample to be in focus at one time. (b) high resolution images, which means that closely spaced features can be examined at a high magnification. Most SEMs require the sample to be conductive, but preparation of the samples is relatively easy.
  • Scavenge Pad. A dummy pad that captures bridging solder as the printed circuit board exits the solder wave, preventing a short.
  • Scavenging. When the squeegee removes solder paste that has been printed into apertures.
  • Schematic. A circuit diagram.
  • Scooping. Scavenging
  • Scoring (V-Scoring). A technique allowing the separation of each printed circuit board from a fabricated array.
  • Screen. A screen mesh covered by a emulsion. The emulsion has openings that match the land pattern of the printed circuit board. During printing adhesive or solder paste is forced through these openings onto the printed circuit board.
  • Screen Printing. The transfer of a pattern onto a surface by forcing a suitable material through a screen with a squeegee.
  • Screen Mesh. The woven fiber or wire structure that supports the emulsion, but does not block the solder paste from printing.
  • Secondary Side. That side of the printed circuit board that is opposite of the primary side (solder side in PTH technology).
  • Section. Microsection
  • Selective (Wave) Soldering. Wave Soldering, Selective
  • Self-Alignment. When a component moves by wetting/surface tension forces of molten solder during reflow heating.
  • Self-Planarizing Head. Head, Self-Planarizing
  • SEM. Scanning Electron Microscope
  • Semiaqueous Cleaning. Cleaning, Semiaqueous
  • Semiautomated Assembly. A process for the manufacture of an electronic assembly carried out by an operator with a combination of manual and automated equipment.
  • SEMATECH. Semiconductor Manufacturing Technology Consortium
  • SEMI. Semiconductor Equipment and Materials International
  • Sensitivity. A measure of the minimum change in an input signal that an instrument can detect.
  • SER. Solvent Extract Resistivity.
  • SERA. Sequential Electrochemical Reduction Analyzer
  • Server. A software application which communicates with another software application (the client). The server normally supplies data or functions to the client. The server can be both a client and a server.
  • Servo Motor. A drive motor that advances linearly.
  • Sequential Electrochemical Reduction Analysis (SERA). A non-destructive technique that characterizes solderability, surface metal oxides, and intermetallics.
  • Shadowing. When a component blocks the heat or solder wave flow from certain areas of the printed circuit board, resulting in incomplete soldering.
  • Shear Strength. The force required to shear apart bonded materials and/or components.
  • Shear Tensile. An adhesive is in tensile loading when the acting forces are applied parallel to the plane of the adhesive. The tensile strength of an adhesive bond is the maximum tensile load per unit area required to break the bond. Expressed in pounds per square inch.
  • Shiner. In fabrication, seeping of resin through an imperfection in the copper foil on the laminate, causing various kinds of problems in multilayer printed circuit boards. Problems include: innerlayer opens due to loss of dry film adhesion and poor oxide coverage in this area can cause delamination.
  • Short. An undesired electrical connection caused by either (1) a bridge between trace paths on a printed circuit board or (2) solder bridging the gap between lead terminations or pads.
  • Shutter. Part of a feeder that protects tape and reel components after the cover tape has been pealed-back.
  • Si. The chemical symbol for silicon
  • SIA. Semiconductor Industry Association
  • Side Cutter. Dikes. A hand tool used to cut wire.
  • Silk Screen. Legend
  • Single Inline Package (SIP). A PTH package with one row of leads extending from the base of the component. Standard lead pitch is 0.100 inch.
  • Single Layer Board. A printed circuit board that contains metallized conductors on one side of the board and no plating in the through holes.
  • Sintering. A process in which powders bond without melting.
  • SIP. Single Inline Package.
  • SIR. Surface Insulation Resistance
  • Skew. A measure of misalignment of a part from its target.
  • SLC. Surface Laminar Circuitry.
  • Slump. The spreading of a paste or gel after printing.
  • Small Outline Integrated Circuit (SOIC). An integrated circuit SMT package with two parallel rows of 8 to 16 gull-wing leads. The pitch is 50 mil.
  • Small Outline J leaded devices. An integrated circuit SMT package with two parallel rows of 16-40 J leads. The pitch is 50 mil.
  • Small Outline Large Integrated Circuit (SOLIC). An integrated circuit SMT package with two parallel rows of 8 to 28 gull-wing leads. The pitch is 50 mil.
  • Small Outline Transistor (SOT). A discrete SMT package with two gull-wing leads on one side of the package and one gull wing lead on the other side.
  • SMC. Surface Mount Component
  • SMD. Surface Mount Device
  • SMD. Solder Mask Defined (Pads)
  • Smear. A deposit caused by drilling heat.
  • SMOBC. Solder Mask Over Bare Copper
  • SMOTL. Solder Mask Over Tin Lead
  • SMT. Surface Mount Technology
  • SMTA. Surface Mount Technology Association
  • Smut. Immersion plate copper
  • Sn. Chemical symbol for the element tin.
  • Snap-Off Distance. The height a stencil is positioned away from the printed circuit board in "off contact" printing.
  • SO. Small Outline (IC package)
  • Soak. Heating from preheat to reflow at a predetermined rate to stabilize component temperatures and activate flux.
  • Soft Ground. Ground, Soft
  • SOIC. Small Outline Integrated Circuit
  • SOJ. Small Outline J leaded device
  • Solder. A fusible metal alloy, consisting primarily of tin and lead, used for the purpose of joining together two or more metals at a temperature below their melting point. Bar, wire, and paste are common forms of solder.
  • Solder Balls. (1) A soldering process residue consisting of small spheres on the printed circuit board surface. (2) Solder bumps.
  • Solder Bridge (ing). Short. An unplanned solder connection.
  • Solder Bump. Solder spheres bonded to pads of components, used for face-down bonding.
  • Solder Connection. Solder Joint.
  • Solder, Eutectic. A solder alloy with eutectic properties.
  • Solder, Low Temperature. Solder with a low melting temperature. For example: 43Sn/43Pb/14Bi is liquidous at 163罜(325罠), compared with eutectic solder which is liquidous at 183罜(361罠).
  • Solder, High Temperature. Solder with a high melting temperature. For example: 10Sn/88Pb/2Ag is liquidous at 290罜(554罠), compared with eutectic solder which is liquidous at 183罜(361罠).
  • Solder Joint. An electrical/mechanical connection that uses solder to join of two or more metal surfaces.
  • Solder Joint, Acceptable. Under effectively managed conditions, solder joints exhibit acceptable attributes as smooth, usually shiny, clearly defined, well feathered (small contact angle), completely wetted metallic bonds between two metal surfaces.
  • Solder Joint, Cold. A solder connection exhibiting poor wetting and a grayish, porous appearance due to insufficient heat, inadequate cleaning before to soldering, or excessive impurities in the solder.
  • Solder Joint, Disturbed. Unsatisfactory connection resulting from relative motion between the conductor and termination during solidification of the solder.
  • Solder Joint, Excessive. Unsatisfactory solder connection wherein the solder obscures the configuration of the connection.
  • Solder Joint, Fractured. A joint showing evidence of cracking, resulting from movement between the conductor and termination, after solidification of the solder.
  • Solder Joint, Insufficient. A solder connection characterized by incomplete coverage of one or more of the metal surfaces being joined or by incomplete solder fillets.
  • Solder Joint, Overheated. An unsatisfactory solder joint, characterized by rough solder surface; dull, chalky, grainy, porous or pitted.
  • Solder Joint, Porous. A joint having a grainy or gritty surface.
  • Solder Joint, Rosin. Unsatisfactory connection that has entrapped rosin flux. This entrapment is usually due to insufficient heat or insufficient time at soldering temperature, or both, not enabling the rosin to rise to the surface of the solder. This results in insufficient bonding and/or high electrical resistance.
  • Solder Leveling. A printed circuit board fabrication process in which hot air or gas "smooths" or removes excess solder on formed joints.
  • Solder Mask. Coating material used to mask or protect selected areas of a pattern from the action of an etchant, solder, or plating.
  • Solder Mask Defined (SMD) Pad. Pad, Solder Mask Defined
  • Solder Mask, Dry Film. A photo-imageable dry film mask allowing a minimum 0.003 to 0.005 inch clearance on each side of the pad.
  • Solder Mask, Liquid Photo-Imageable (LPI). LPI is he standard mask for SMT applications. It requires a clearance of 0.001 to 0.0015 inch on each side of the pad. This is very attractive for fine pitch applications, because it is a thin coating.
  • Solder Mask, Wet Film. A screenable solder mask. Wet film works well on PTH and sparsely populated SMT printed circuit boards.
  • Solder Pad. Termination area on a printed wiring conductor. Land. Pad.
  • Solder Paste. A homogeneous combination of solder particles (ranging in diameter from about 4 to 40 microns), flux, solvent, and a suspension agent used in the surface mount reflow soldering process. Solder paste has a high viscosity of approximately 900,000 centipoise. Solder paste is commonly applied by printing, dispensing, preforms, and manual methods.
  • Solder Powder. Solder paste manufacturers mix a powder of solder alloy with other material to produce solder paste. Solder powder is the major ingredient that affects the printability of the paste and the quality of the solder joint.
  • Solder Preform. A manufactured configuration of solder with a consistent amount of solder and flux, if flux is included. Suppliers usually design preforms for a specific application.
  • Solder Side. On printed circuit boards with components on only one side, the side of the PCB that is opposite to the component side.
  • Solder Splatter. Extraneous irregular-shape solder fragments.
  • Solder Spike. A cone shaped peak or sharp point of solder usually formed by the premature cooling and solidification of solder on removal of the heat source.
  • Solder Sucker. A hand soldering tool used to remove excess solder from a connection.
  • Solder Webbing. A film of solder that is parallel to, but not necessarily fully attached to, a surface intended to free of solder.
  • Solder Wick. A braid of solderable material, often copper, used in hand soldering to remove excess solder from a connection.
  • Solder Wicking. Wicking
  • Solder, Wire/Core. An eutectic or near eutectic solder alloy with a hollow flux filled core, formed in varying diameters from about 0.012" to 0.060" for specific hand soldering activities.
  • Solderability. (1) The property of a surface that allows it to be wetted by a molten solder. (2) The ease with which solder adheres to a basis metal surface such as a component lead, solder termination pad, or conductor hole pad and wall. Surface oxides and intermetallics interfer with solderability.
  • Soldering. (1) A the method for mechanically and electrically joining two metals using an alloying metal (solder), a cleansing agent (flux), and heat without direct fusion of the base metals. (2) Metallurgical joining two metal surfaces using a metal filler with a melting point below 800罠 (some say 500罠) without diffusion or intermetallic formations (some say).
  • Soldering, Conduction. Method of soldering by transferring heat to the soldering area with a soldering iron or machine.
  • Soldering, Dual Wave. Wave Soldering, Dual
  • Soldering, Hot Bar. A process in which a heated bar simultaneously solders all the leads of a device to the pads on a PCB.
  • Soldering Iron. Iron. A hand soldering tool.
  • Soldering, Laser. A method of soldering in which the heat required to reflow a solder interconnection is provided by a laser (YAG or CO2). In this process, the solder joints are heated sequentially and cooled rapidly.
  • Soldering, Reflow. Reflow Soldering
  • Soldering, Resistance. Method of soldering that passes a current between two electrodes through the area to be soldered.
  • Soldering, Wave. Wave Soldering
  • Solidus. The temperature when an alloy begins to melt.
  • SOLIC. Small Outline Large Integrated Circuit
  • Solids Content. (1) The portion of resin in a flux formulation. (2) The portion of metal powder in a wet solder paste.
  • Solvent. A liquid used to clean materials.
  • Solvent Cleaning. Cleaning, Solvent
  • Solvent Extraction. The removal of one or more components from a liquid mixture by intimate contact with a secondary liquid that dissolves the impurities, but not the liquid being purified.
  • Solvent Extract Resistivity. Resistivity of Solvent Extract
  • SON. Small Outline No-Lead (IC package)
  • SOT. Small Outline Transistor
  • SPC. Statistical Process Control
  • Special Process. The results of special processes cannot be verified fully by subsequent nondestructive inspections. Soldering, brazing, and welding are examples of special processes.
  • Specific Gravity. The density (mass per unit volume) of any material divided by that of water at a standard temperature. Specific gravity of water = 1:00.
  • Specific Heat. The ratio of a material's thermal capacity to that of water at 15薈.
  • Spike. (1) A transient disturbance of an electrical circuit caused by, for example, load variations on the AC power line. (2) The portion of a solder reflow profile, after soaking and before cooling, when temperature is increased rapidly to the solder paste liquidous point.
  • Splice. A strip of material used to join two pieces of tape.
  • Split Terminal. Terminal, Bifurcated (split)
  • Spray Fluxer (ing). Fluxer, Spray
  • Sprocket Holes. Holes along the edge(s) of component tape used for handling, indexing, and in some cases, registration.
  • Sprocket Pitch. Pitch
  • Sputtering. A form of physical vapor deposition (PVD) in which a metal target is exposed to a plasma made from a gas like argon which is not chemically reactive. The excited gas atoms hit the target and knock off metal atoms which deposit onto a wafer placed below, building up the desired metal film.
  • SQC. Statistical Quality Control
  • Squeegee. A metal or rubber blade used in screen or stencil printing to wipe across the screen (stencil) to force solder paste through openings in the screen (stencil).
  • Squeegee Downstop. The up and down travel of the squeegee head.
  • Squeegee Pressure. The pressure the squeegee exerts on the stencil during the print cycle.
  • Squeegee Print Speed. The rate a print head moves the squeegee across the stencil
  • Squeegee Stroke. The distance the print head moves the squeegee over the stencil.
  • Staking Compound. An electrically nonconductive adhesive material used for additional support after a component has been attached by mechanical or soldering process.
  • Static Dissipative. Electrostatic Dissipative Material
  • Statistical Process Control (SPC). A quality control method that focuses on continuous monitoring of the process with the intent to achieve closed loop control of the process to eliminate defective product.
  • Statistical Quality Control (SQC). Applies statistical techniques to the observed characteristics of a process.
  • Stencil. A thin sheet of brass or stainless steel with openings that match the land pattern of the printed circuit board. During printing, adhesive or solder paste is forced through these openings onto the printed circuit board.
  • Stencil, Chemical Etched. A stencil with chemical etched apertures.
  • Stencil, Electroformed. A stencil with electroformed apertures.
  • Stencil, Electropolished. A stencil with electropolished apertures.
  • Stencil, Laser Cut. A stencil with laser cut apertures.
  • Stencil With Trapezoidal Apertures. Aperture, Trapezoidal
  • Stencil, Peel-Away Speed. The rate a stencil is removed from a printed circuit board after printing.
  • Stencil Printing. The transfer of a pattern onto a surface by forcing a suitable material through a stencil with a squeegee.
  • Stencil, Step Down. A stencil of varying thickness that allows printing different amounts of solder paste or adhesive.
  • Step Down Stencil. Stencil, Step Down
  • Stepper Motor. A drive motor that advances in small increments (steps).
  • Step & Repeat. A process where the printed circuit board layout or component placement is repeated many times in evenly spaced rows.
  • Stick. Tube
  • Straight Pin Terminal. Terminal, Straight Pin
  • Straight-Through Termination. A conductor termination extending through a printed circuit board without subsequent forming of the lead.
  • Stress Relief. The formed portion of a conductor that provides sufficient length to minimize stress between terminations.
  • Stud Terminal. Terminal, Stud
  • Sub Process. A sub process may be part of a process. In the wave soldering process, several sub processes are involved to effect acceptable solder joints.
  • Substrate. A supporting insulating material upon which parts, substrates, and elements are attached.
  • Substrate, Inorganic. Ceramic or metal materials.
  • Substrate, Organic. Layers of paper impregnated with phenolic resin or glass cloth impregnated with epoxy resin, polyimide, cyanate ester, BT resin etc.
  • Subtractive Process. A process in which a substrate is first covered with conducting material, then any unwanted material is subsequently removed, or subtracted.
  • Super Mole®. A brand name for a profiler.
  • Supervisory Control. The use of computers to accomplish operator interface, data acquisition, process monitoring and some degree of production control.
  • Supportive (ed) Hole. A hole in a printed circuit board that has its inside surface plated or otherwise reinforced.
  • Surface. An object謘 area having no depth.
  • Surface Acoustic Microscope (SAM). Scanning Acoustic Microscope. Acoustic Microscope
  • Surface Insulation Resistance (SIR). The electric resistance of an material between two points to determine cleanliness.
  • Surface Mount Technology (SMT). A manufacturing process that attaches components on the surface of the printed circuit board, rather than inserting components into plated through holes.
  • Surface Mount Technology Association (SMTA) is a SMT industry promotional and educational organization.
  • Surface Resistivity. The surface resistivity is an inverse measure of the conductivity of a material and equal to the ratio of the potential gradient to the surface, where the potential gradient is measured in the direction of current flow in the material.
  • Surface Tension. An effect of the forces of attraction between the molecules on the surface of a liquid.
  • Surfactant. A chemical added to water to lower the surface tension and allow better cleaning in small spaces.
  • Surftape. A punched carrier for tape and reel packaging of surface mount devices. It features a flexible, pressure-sensitive adhesive base, negating the need for cover tape.
  • Surge. A sudden change (usually an increase) in the voltage on a power line. A surge is similar to a spike, but it lasts longer.
  • Syringe. A tool for applying material through a thin needle shaped opening.
  • Systems Integration. The ability of computers, instrumentation and other components to share data or applications.

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    T

  • TAB. Tape Automated Binding
  • Tack. The property of an adhesive or paste to form a bond.
  • Tact Time. Time for a placement head to move to a placement location from a pick-up location.
  • Tackiness. The ability of solder paste to hold components in place after placement.
  • Taguchi. (1) Genichi Taguchi. (2) A design of experiments technique (fractional factorials) that requires fewer experiments than conventional methods.
  • TAP. Test, assembly and packaging or the back-end of semiconductor manufacturing (BEOL)
  • Tape Automated Bonding (TAB). A high lead count SMT integrated circuit package aimed at very high volume products and specialized low volume products, requiring secondary processing with specialized machinery.
  • Tape, Carrier. The part of the tape of a tape and reel with a pocket and sprocket holes that presents a part for pickup.
  • Tape Ball Grid Array (TBGA). A brand name for TAB package form.
  • Tape Bonding. Bonding, Tape
  • Tape Carrier Package. A brand name for Tape Automated Bonding (TAB).
  • Tape, Cover. The part of a tape and reel that holds a component in the pocket of the carrier tape.
  • Tape, Embossed. Tape, Carrier
  • Tape Pitch. Pitch
  • Tape Width. Carrier tapes come in 8 mm, 12 mm, 16 mm, 24 mm, 32 mm, 44 mm, and 56 mm widths.
  • Tape & Reel. (1) A package form that allows the feeding of components to a placement machine, consisting of cover and carrier tapes and a reel. (2) A package form that allows the feeding of components to an insertion machine, consisting of a roll of components held in place by at least one pair of thin adhesive tapes positioned face to face and a reel.
  • Tarnish. Oxidation
  • TB-BGA. Top-Bottom Ball Grid Array
  • TBGA. Tape Ball Grid Array
  • TCE. CTE
  • TCP. Tape Carrier Package
  • Technology Buy. Purchases of advanced equipment for developing next generation technologies and other R&D, as opposed to a capacity buy.
  • TEM. Transmission Electron Microscope
  • Tenting. Via tenting
  • Terminal. A tie point device used for making electrical connection.
  • Terminal, Bifurcated (split). A terminal with a slot or split opening in which conductors are placed before soldering.
  • Terminal, Cup. A hollow, cylindrical terminal to accommodate one or more conductors.
  • Terminal, Hook. A terminal formed in a hook shape.
  • Terminal, Pierced (Perforated). A terminal containing a hole through which conductors are placed before soldering.
  • Terminal, Straight Pin. A round post-type smooth terminal, with no grooves.
  • Terminal, Stud. An unbendable conductor termination extending through a printed circuit board.
  • Terminal, Turret. A round post-type grooved stud around which conductors are fastened before soldering.
  • Termination. The point at which electrical conductors are joined.
  • Termination Area. A conductive surface on a printed circuit board used for making electrical connections. A solder pad.
  • Terpene. A hydrocarbons with the empirical formula C10H16 and a characteristic odor. Turpentine is mainly a mixture of terpenes. Other common terpenes are pinene and limonene.
  • Test, Automated. Computer controlled electrical testing of parts, assemblies, or finished products.
  • Test, Built-In (BIT). An electrical testing technique which adds hardware to the chip to allow the integrated circuit to test itself with minimal use of test equipment.
  • Test, Combinational. A test method that uses automatic test equipment to measure component parameters (i.e., in-circuit testing) and performance (i.e., functional testing).
  • Test Coupon. A portion of a printed circuit board containing test points.
  • Test Fixture. Equipment that interfaces between test equipment and the unit being tested.
  • Test, Functional. An electrical test of an assembly under actual operating conditions.
  • Test, In-Circuit (ICT). An automated test method that measures parameters such as continuity and short and open circuits on an assembled printed circuit board. It also tests components mounted on the printed circuit board.
  • Test, Manufacturing Defects Analyzer (MDA). An automated test that measures component values, but does not supply power to the printed circuit board.
  • Test Pad. Pad, Test
  • Test Point. A node with specific access to an electrical circuit used for electrical testing purposes.
  • Tg. Glass Transition Temperature
  • Thermal Conductor. A class of materials-usually metals-that easily conduct heat. Examples include copper, aluminum, and beryllia.
  • Thermal Conductivity. Ability of a material to conduct heat.
  • Thermal Cycling. A method used to induce stresses on electrical components by means of sequential heating and cooling in an environmental chamber.
  • Thermal Profile. Profile
  • Thermal Relief. A wagon wheel-shaped relief pad etched in the copper of a ground plain around a through hole. Without the thermal relief, the plane robs the component pad and component lead from the heat required to fully fill the solder joint.
  • Thermal Shunt. A device with good heat dissipation characteristics used to conduct heat away from an article being soldered.
  • Thermal Via. Via, Thermal
  • Thermocompression Bonding. Bonding, Thermocompression
  • Thermocouple. A temperature sensing device that generates a thermoelectric voltage caused by differences in two metal junction.
  • Thermode. A set of blades or bars that hold component leads in place and reflow solder them to bonding pads during hot bar reflow soldering.
  • Thermoplastic. A material capable of being repeatedly softened by heat and hardened by cooling.
  • Thermoplastic Adhesive. Adhesive, Thermoplastic
  • Thermoset. A material which will undergo a chemical reaction by action of heat, catalysts etc.. Leading to a relatively infusible state.
  • Thermoset Adhesive. Adhesive, Thermoset
  • Thermosonic Bonding. Bonding, Thermosonic
  • Theta. Amount of rotation.
  • Thief. Thieving
  • Thieving. A pattern of features added to outer layer designs on printed circuit boards to balance the plating distribution.
  • Thin Small Outline Package (TSOP). An integrated circuit SMT package with two parallel rows of 20 to 48 gull-wing leads. The pitch is 20 mils.
  • Thixotropic. The property of some pastes and gels at rest that become more fluid when stressed.
  • Threshold Limit Value. A guideline for the exposure of humans to hazardous materials. It is expressed as a TWA of the parts per million of vapor in air.
  • Through Hole. Plated-Through-Hole (PTH)
  • THT. Through Hole Technology. Pin-Through-Hole (PTH)
  • Time Stamp. Information added to a unit of data to indicate the time that it was processed.
  • Time Weighted Average (TWA). A measurement parts per million of vapor in air to assess exposure of humans to hazardous materials.
  • Tin Copper Intermetalic. Intermetalic, Tin Copper
  • Tin Drift. Solder in a solder pot can become tin depleted over the long term, because tin oxidizes more easily than lead and is removed with the dross.
  • Tin Lead Plating. Plating, Tin Lead
  • Tinning. The coating of a surface with a uniform layer of solder.
  • Tip. (1) Needle. Nozzle. A tool used in dispensing adhesives. (2) The heat transfer portion of a soldering iron. Operators select soldering iron tip shape according to the size of the solder joint.
  • Tomb Stone. When a small rectangular or cylindrical component has flipped to a vertical position during reflow. Some make a distinction about the amount the component is lifted from the pad with terms draw bridge and tomb stone. We think they don謙 have enough to do.
  • Tooling Hole. Alignment Hole. A non-plated hole on a printed circuit board that provide for registration and hold-down during manufacturing processes.
  • Touchless Centering. Centering, Vision
  • Touch-Up. Rework
  • TQFP. Tape Quad Flat Package
  • Transmission Electron Microscope (TEM) was developed earlier than the scanning electron microscope (SEM) and differs in a number of fundamental ways. First, while the SEM uses an electron beam to excite secondary electrons from the sample's surface, the TEM sends electrons directly through the sample. Second, while the SEM uses the information gained from the detected secondary electrons to produce an image on a computer monitor, the image viewed using a TEM is in essence the sample's shadow. Electrons that pass through the sample brighten the fluorescent viewing screen, while the screen remains darker beneath parts of the sample which do not yield as easily to electrons.
  • Trapezoidal Aperture. Aperture, Trapezoidal
  • Trapezoidal Aperture Stencil. Aperture, Trapezoidal
  • Tray. Tray, Waffle
  • Tray Elevator. Feeder, Tray
  • Tray Feeder. Feeder, Tray
  • Tray, Waffle. A type of packaging used to supply parts, most often ICs, with separations to keep the parts in position.
  • TSOP. Thin Small Outline Package
  • Tube. A type of packaging used to supply parts, usually ICs.
  • Tubelet. A tubular metal part. Its ends may or may not be flared.
  • Turbocharge. Turboelectric
  • Turboelectric. Electricity generated by friction.
  • Turbulent Wave. A section of a dual wave soldering machine used to solder bottom side SMT components.
  • Turret Head. A pick-up and placement head with multiple pick-up locations that generally rotates parallel to the printed circuit board.
  • Turret Terminal. Terminal, Turret
  • TÜV Rheinland. A German safety standard certification organization.
  • TWA. Time Weighted Average
  • Twist. A diagonal corner to diagonal corner variation from known flatness of a printed circuit board.
  • Type I Assembly. A surface mount assembly with surface mount components on one or both sides of the substrate.
  • Type II Assembly. A surface mount assembly with surface mount components on one or both sides of the substrate and through hole devices on the primary side.
  • Type III Assembly. A surface mount assembly with surface mount components on the secondary side of a PCB and through hole devices on the primary side.

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    U

  • µBGA®. Micro BGA®.
  • UL. Underwriters Laboratories
  • Ultrasonic. Using frequencies above 20,000 hertz in cleaning technology or wave solder flux dispensing.
  • Ultrasonic Bonding. Bonding, Ultrasonic
  • Ultrasonic Cleaning. Cleaning, Ultrasonic
  • Ultrasonic Fluxer (ing). Fluxer, Spray
  • Undercut. The amount of metal removed from under the resist during etching.
  • Underfill. In flip chip applications, the material injected under the die after testing to match CTE of the silicon chip to the substrate.
  • Underwriters Laboratories (UL). A U.S. safety standard certification organization.
  • "Universal" Solvent. Water is capable of dissolving all material types to some extent over time.
  • Unsupported Hole. A hole containing no plating or other type of conductive reinforcement.
  • Uniform Resource Locator (URL). The name (or string of characters) that uniquely identifies each Web site.
  • URL. Uniform Resource Locator
  • UV. Ultraviolet

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    V

  • V-Scoring. Scoring
  • Vapor Degreaser. Cleaning, Vapor Degreaser
  • Vapor Phase Soldering. A solder reflow technology that uses a heated solvent to melt the solder.
  • Vaporware. Products, usually hardware or software, that exist only in the minds of the people who are trying to sell them to you.
  • Via. A plated-through hole used as a through connection between layers on the printed circuit board. Vias are not intended to be used for component lead insertion.
  • Via, Blind. A via extending between inner layers and one outer surface of a multilayer printed circuit board.
  • Via, Buried. A via that inter connect layers on a multilayer printed circuit board.
  • Via Tenting. A via that is covered with material to prevent contact with process materials. A printed circuit board assembly set which covers a plated via and the surrounding area with solder mask.
  • Via, Thermal. A plated via positioned to remove heat from a component.
  • Via, Micro. Microvia
  • Vib (Vibratory) Feeder. A machine that presents parts in tube carriers for pickup by a placement machine.
  • Viscosity. A measure of a material謘 resistance to flow or shape change. Centipose and millipascal are common units for expressing viscosity. A higher reading indicates a thicker material.
  • Vision Centering. Centering, Vision
  • VLSI. Very Large Scale Integration
  • VOC. Volatile Organic Compound.
  • VOC Free Flux. Flux, Low Residue
  • Void. (1) A space enclosed on all sides by the solder. (2) An absence of material.
  • Volatile Organic Compound (VOC). An organic compound that is readily vaporized in air. Local regulations often define VOCs.

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    W

  • Watt
  • Waffle Tray. Tray, Waffle
  • Wafflepack. Tray, Waffle
  • Water Cleaning. Cleaning, Aqueous
  • Water Soluble Flux. Flux, Water Soluble
  • Wave, "A." Asymmetrical wave. An Electrovert term for the laminar wave in contour inerting systems. The contour systems are open to the atmosphere and have nitrogen diffusers along the sides of the wave where they re-enter the solder pot. It is asymmetrical because 70% of the solder flows over the front of the nozzle and the remaining 30% flows over the back of the nozzle. Most laminar waves have only a trickle flowing over the back.
  • Wave Fluxer (ing). Fluxer, Wave
  • Wave Oil. A high temperature oil floated on the solder surface of a solder pot to reduce dross formation.
  • Wave Soldering. (1) A conduction machine soldering process that brings a printed circuit assembly in contact with the surface of continuously flowing and circulating molten solder. (2) A machine that creates solder joints by contacting the bottom side terminations on a board with the molten solder. This contact makes the connections as wave pressure, wetting, and capillary action force the solder to flow up holes and component leads to wet them to the board surface.
  • Wave Soldering, Dual. A wave soldering process consisting of an initial turbulent wave followed by a laminar (flat) wave used for two sided SMT printed circuit boards. The turbulent wave ensure full solder coverage. The laminar wave removes shorts, bridges, and icicles.
  • Wave Soldering, Selective. (1) Using a pallet to allow only selected areas on a printed circuit board to contact the solder wave and to protect other areas of the board from contact with the wave. (2) Using a solder fountain (a specialized soldering machine) and specialized chimneys to solder only selected area on a printed circuit board.
  • Webbing. (1) Solder Mask: Spacing between adjacent feature, creating a web of solder mask. (2) Solder webbing.
  • Wedge Bonding. Bonding, Wedge
  • Wet Etching. Etching away of layers on a wafer by immersion in a chemical bath.
  • Welding. A metallurgical joining process of metals using diffusion and intermetallic formations beyond the metal surfaces to a specified depth. Welding uses temperatures well above 800罠.
  • Wet Film (Solder Mask). Solder Mask, Wet Film
  • Wet. A screened material.
  • Wetting. (1) The flow and adhesion of a liquid to a solid surface, characterized by smooth, even edges. In reference to soldering wetting is the formation of a uniform, smooth, unbroken and adherent layer of solder onto a base metal. (2) Wetting requires a solid surface to be completely "coated" by a liquid. This means the liquid maintains intimate contact with all solder termination areas without resistance or any indication of "pulling" back from their surfaces. In solder joining, the liquid is molten solder. When two solderable metal surfaces are wetted, they may become joined upon solder solidification.
  • Wetting Agent. Surfactant.
  • Wetting Balance. An instrument used to measure wetting forces, and consequently, estimate solderability.
  • Whisker. A needle-like, metallic growth on the surface of a printed circuit board.
  • White Tin. A coating applied during printed circuit board fabrication to protect copper features from oxidation.
  • Water-White Rosin. Rosin, Water-White
  • Wick. Solder Wick
  • Wicking. A flow of molten solder, flux, cleaning solvent, or other solution by capillary action.
  • WIP. Work In Process
  • Wire Bond (ing). Bonding, Wire
  • Wire Solder. Solder, Wire/Core
  • Work(ing) Life. The time a material can remain on a stencil before loosing critical properties.
  • Worknest. The tooling that holds a printed circuit board in-place during processing.

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    X

  • XRF. X-ray Fluorescence
  • X-Ray. A stream of relatively high-energy photons with wavelength between 0.01 to 10 nanometers used for their penetrating power.
  • X-Ray Fluorescence (XRF) is used to identify the presence and quantity of chemical elements. A typical XRF system consists of: (a) an excitation source either x-ray tube or radioisotope such as 109Cd; (b) a detector, such as lithium drifted silicon or high purity germanium, and its associated electronics; and (c) a pulse height analyzer and computer for analyzing the fluorescent spectrum.
  • X-Ray Lithography. Lithography, X-Ray
  • X-Windows. Defines an interface standard between an application and a user interface to allow the display of remote applications on a network.
  • X-Y Axis. In the plane of the printed circuit board. X is usually left and right. Y is usually forward and backward.

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    Y

  • YAG. Yttrium Aluminum Garnet (LASER)
  • Yield. First Pass Yield

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    Z

  • Z-Axis. Perpendicular to the printed circuit board surface.

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  • µBGA®. Micro Ball Grid Array (Tessera)
  • µC. Microcontroller
  • µm. Micron
  • µP. Microprocessor
  • µVia. Microvia 
  • 4GE. Fourth-Generation Environment
  • 4GL. Fourth-Generation Language
  • 63Sn/37Pb. Eutectic Solder
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