SMT Terms and Definitions


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“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-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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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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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.

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O

P | Q | R | S | T | U | V | W | X | Y | Z | NON-LETTER




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 occu