PCB Glossary

The tests that determine the acceptability of boards as agreed to by purchaser/vendor.

The maximum number of defects per 100 units that can be considered satisfactory as a process average.

A series of holes in successive layers. Each set has a common centre or axis. The holes of a multi-layer printed board provide access to the surface of the land in one of the layers of the board.

The deviation of the measured or observed value from the accepted reference.

A thermosetting, transparent resin.

A mixture of rosin and small amounts of organic-halide or organic-acid activator, which improves the ability of a flux to remove surface oxides from the surfaces being joined.

A treatment that renders non-conductive material receptive to electroless deposition.

Semiconductor devices, such as transistors and diodes, that can change its basic characteristics in an powered electrical circuit, such as amplifiers and rectifiers.

A process for obtaining conductive patterns by the selective deposition of conductive material on clad or unclad-based material.

The metal layer that adheres a barrier metal to a metal land on the surface of an integrated circuit.

A substance such as glue or cement used to fasten objects together. In surface mounting, an epoxy adhesive is used to adhere SMDs to the substrate.

The change of a property, e.g. solderability, with time.

The non-conductive air space between current carrying conductors such as traces, pads, ground planes, etc.

A procedure for solving a problem, usually mathematical.

A thermosetting resin with good electrical properties used for moulding the bodies of components.

The surrounding environment coming into contact with the system or PCB in question.

A circuit comprised primarily of individual (discrete) components, such as resistors, capacitors, diodes, transistors, etc. The circuit output is a continuous electrical signal that varies in frequency, amplitude, etc., as a function of the input. The magnitude is represented by physical variables such as voltages, current, resistance, rotation, etc.

A tool used to verify the design (or portions thereof) in the analog domain by applying virtual test signals to a virtual model of the design.

At the board level, various analog test signals are applied to a PCB through a switch to point out current outputs.

A system measuring component values on a populated PCB before power is applied.

Anchoring Spur - An extension of a land（like one or two blind paths）on a flexible printed board that extends beneath the cover lay to assist in holding the land to the base material.

The angle between the face of the squeegee and the surface of the screen.

Text or legend pertinent to a board design; text appears off the board areas and consists of lettering and symbols while legend appears on the boards.

That portion of conductive material completely surrounding a hole.

Acronym for "American National Standards Institute", an organization formed by industry and the US Government to develop trade and communication standards.

Automatic Optical Inspection.

List containing the shapes and dimensions of pads and tracks, etc., to expose on the film in a photoplotter.

Acceptable Quality Level. The maximum number of defectives likely to exist within a population lot that can be considered to be contractually tolerable.

A water-based method that may include neutralizers, saponifiers, surfactants, dispersants and anti-foaming agents.

The resistance of a material to the effects of a high voltage, low-current, under prescribed conditions, passing across the surface of the material. The resistance is stated as a measure of the total elapsed time required to form a conductive path of the surface (material carbonized by the arc).

A group of elements or circuits (or circuit boards) arranged in rows and columns on a base material.

An accurately scaled configuration used to produce the artwork master or production master.

The photographic film or glass plate that embodies the image of the PCB pattern, usually on a 1:1 scale.

Acronym for "American Standard Code for Information Interchange"; a seven-bit code that assigns numeric values to letters of the alphabet, the ten decimal digits, punctuation marks and other characters.

A ratio of the PCB board thickness to the diameter of the smallest hole.

A number of parts, subassemblies, or any combination thereof joined together.

A drawing depicting the locations of components, with their reference designators (q.v.), on a printed circuit. ii:The document that shows a printed board, components and any information necessary to describe joining them together in order to perform a specific function.

A drawing describing the locations of components on a PCB.

A manufacturing facility for attaching and soldering components to a printed circuit.

A computer language of brief expressions for translation into a machine language.

Automated Test Equipment. Equipment that automatically tests and analyzes functional parameters to evaluate performance of the tested electronic devices.

Assembling discrete components to PCBs via electrically controlled equipment.

Equipment that automatically tests and analyzes functional parameters to evaluate performance of the tested electronic devices.

Hardware that automatically analyses functional or static parameters to evaluate performance degradation. It also performs fault isolation.

American Wire Gauge. A method of specifying wire diameter; the higher the number, the smaller the diameter.

A lead extending out the end and along the axis of a resistor, capacitor or other axial part rather than from the bottom.

Two or more polar and non-polar solvents that behave when mixed as a single solvent to remove polar and non-polar contaminants with a boiling point lower than its components.

Blind and Buried via holes.

An in-circuit test procedure for digital circuitry.

Mother Board. Also called back plane, or matrix board. A relatively large printed circuit board on which modules, connectors, sub-assemblies or other printed circuit boards are mounted and inter connections made by means of traces on the board.

A PCB having all lines, pads and layers intact but without components installed. An unassembled PCB.

The cylinder formed by plating through a drilled hole.

The original, thin copper foil present on one or both sides of a copper clad laminate. During PCB manufacture, part of this base copper will be removed by etching. Conductors on the simplest PCBs consist of base copper only.

Coated copper layer on the board. It can either be characterized by weight or thickness of the coated copper layer. For instance, 0.5, 1 and 2 ounces per square foot are equivalent to 18, 35 and 70 um-thick copper layers.

The substrate material upon which the conductive wiring pattern may be formed.

The insulating material (either rigid or flexible ) as well as the copper foils bonded on one or both sides. It is a synonym for copper-clad laminate, i.e., the basic raw material for PCB manufacture. This also supports all components after assembly.

The thickness of the base material, excluding metal foil or material deposited on the surface.

The ease with which a metal or metal alloy surface can be wetted by molten solder under minimum realistic conditions.

The ease with which a metal or metal alloy can be wetted by molten solder.

Bare Board Test.

A test fixture consisting of a frame and a holder containing a field of spring-loaded pins that make electrical contact with a planar test object (i.e., a PCB).

A method of PCB testing involving a fixture containing a field of spring-loaded pins that are co-ordinated with strategic points or nodes on the board to which they are brought into contact.

A connector contact which is a flat sprint folded to provide a uniform spring rate over the full tolerance range of the mating unit.

Ball Grid Array. Leadless array packaging technology in which solder balls are mounted to the underside of the package.

An array of circuits on a larger "mother" panel.

A condition in which liquid solder resist or rotation spreads larger than the defined apperture.

A via that reaches only one layer beneath the outer layer on one side of a muti-layer board.

De-lamination in the form of a localized swelling and separation between any of the Layers of a lamination base material, or between base material and conductive foil or protective coating.

A localized swelling and separation between any of the layers of a laminated base material, or between base material and conductive foil. It is a form of de-lamination. Also separation of solder mask layer and conductive pattern.

A void in the solder fillet caused by outgassing from the barrel of a plated through hole.(see also outgassing)

Bluetooth is a short-range (up to 10m) 2.4GHz wireless connectivity standard intended for such applications as wireless personal area networks (PANs). These PANs can be used to exchange data between devices such as cellphones, digital cameras, printers and household appliances at data rates of up to 721 Kbps (kilo bits per second).

An external layer of resin over the reinforcing structure of base material.

A measure of the ratio of the area of the board used by parts to the total available area of the board. A board with less than 50 to 60 per cent of the available area should be able to be done single-sided, more than 75 to 80 per cent may have to go to multi-layer.

The overall thickness of the base material and all conductive materials deposited thereon.

The portion of an electronic component exclusive of its pins or leads.

A comprehensive listing of all subassemblies, components, and raw materials that go into a parent assembly, showing the quantity of each required to make the assembly.

The common area between a lead and a land to which it has been terminated.

A failure condition in which a lead is separated from its bonding surface.

The force perpendicular to a board's surface required to separate two adjacent layers of the board, expressed as force per unit area.

An adhesive layer used in bonding together other discrete layers of multi-layer printed board during lamination.

The duration from hot-bar-heat-up (contact with lead and pad) until the solder joint is completed.

Patterns that appear in the border area, such as tooling features, test patterns and registration marks.

A self-test designed into components at the silicon level, permitting testing via a built-in, four-or-five-pin test bus accessing I/O pins

The deviation from the flatness of a board characterized by a roughly cylindrical or spherical curvature. If the board is rectangular, its four corners are in the same plane.

A conductor which connects electrically two or more leads on a printed board assembly. Some branched conductors, notably ground, support and re-set signal, connect many leads.

A metal alloy (solder) which melts above 450℃ but below metals being joined.

The voltage at which an insulator or dielectric ruptures or at which ionization and conduction take place in a gas or vapour.

Solder that spans across two or more conductors causing an electrical short-circuit.

A condition where excess solder builds up in the air gap between conductors and causes them to short together. Solder bridging generally occurs during the wave soldering process. Bridging is basically short-circuiting of a pad to an adjacent track or pad on a board.

(prepreg) Partially cured resin (mostly reinforced with glass cloth) which will soften under a special range of temperature and which can be used to bond together cured laminate sheets to form a multi-layer board.

Laminate impregnated with a resin and cured to an intermediate stage (B-stage resin). Normally designated as prepreg.

A resin in an intermediate state of cure. The cure is normally completed during the laminating cycle.

An electrical testing method that allows the tested devices to test itself with specific added-on hardware.

A swelling of a printed board that is usually caused by internal de-lamination or separation of fibres.

A via that does not reach a surface layer on either side of a multi-layer board. The via transcends only inner layers of the board.

A method of testing devices via electrical stress vs temperature and/or time so that units prone to failure are eliminated.

A ridge left on the outside copper surface after drilling.

A heavy trace or conductive metal strip on the printed circuit board used to distribute voltage, grounds, etc., to smaller branch trances.

A conduit, such as a conductor on a printed board, for distributing electrical energy.

A capacitor which provides a comparatively low impedance ac (alternating current ) around a circuit element.

Computer Aided Design

Computer-aided design that permits the interactive use of computers, programs and procedures in the design process. Decisions are made by the operator while the computer provides the data manipulation functions.

Computer-aided design is the use of special software tools to formulate printed circuit patterns. Computer-aided manufacturing translates such designs into actual products.

Computer Aided Manufacturing.

The files used for manufacturing PCB including Gerber file, NC Drill file and Assembly Drawings.

The property of a system of conductors and dielectrics which permits storage of electricity when potential difference exists between conductors.

The electrical interaction between two conductors caused by the capacitance between them.

A phenomenon of force adhesion and cohesion that prompts liquids ( molten solder) to flow against gravity between closely spaced solid surface, such as component leads and pads.

Printed Board. The general term for completely processed printed circuit or printed wiring configuration. It includes signle, double, and multi-layer boards, both rigid and flexible.

Special sheet adhesive material used for bonding polyimide multi-layer boards and flexi-rigids (similar to prepreg = B-Stages).

A chemical that speeds or changes the cure of a resin but does not become a part of the final product. Examples: hardeners, promoters, inhibitors.

Ceramic Ball Grid Array. A ball grid array package with a ceramic substrate.

A corner which has been rounded or shaped to eliminate an otherwise sharp edge.

The ratio of voltage to current in a propagating wave, i.e., the impedance which is offered to this wave at any point of the line. The characteristic impedance is expressed in ohms.

Pen plots that are suitable for checking only. Pads are represented as circles and thick traces as rectangular outlines instead of filled-in artwork. This technique is used to enhance the transparency of multiple layers.

A protective coating produced by the chemical reaction of a metal with a chemical solution.

The chemical process for cleaning conductive surfaces exposed within a hole.

In this technology integrated circuits are glued and wire-bonded directly to printed circuit boards instead of first being packaged.

The individual circuit or component of a silicon wafer, the leadless form of an electronic component.

Component packaging technology in which bare integrated circuits are attached directly to the surface of a substrate and interconnected to the substrate most often by means of microscopic wires.

Large computer-based systems that test individual ICs, especially LSI and VLSI.

Generic term for volume tester of PCB`s, such as bed-of-nails, footprint, guided probe, internal trace, loaded board, bare board and parts testing.

A layer of a printed board containing conductors, including ground and voltage planes.

A crack in the plating extending around the entire circumference of a plated through-hole.

A condition of the base material to which a relatively thin layer or sheet of metal foil has been bonded at one or both of its sides, e.g. a metal clad base material.

A relatively thin layer or sheet of metal foil which is bonded to a laminate core to form the base material for printed circuits.

An in-circuit test fixture to probe both sides of a PCB.

TG-value, temperature at which resin ceases to act as a solid, Till this temperature, no separation will take place between resin/copper/reinforcement.

Metal to metal gaps on a board.

A hole in the conductive pattern larger than, but concentric with, a hole in the printed board base material.

A connection made by a wire which is passed through a hole in a printed circuit board, and subsequently formed, or clinched, in contact with the conductive pattern on each side of the board, and soldered.

A thin layer of material, either conductive or insulating, applied over components or base materials.

A configuration in which a chip is directly attached to a printed circuit board or substrate by solder or conductive adhesives.

The fractional change in dimension of a material for a unit change in temperature expressed in ppm/C.

A solder connection that exhibits poor wetting and that is characterized by a greyish porous appearance.

In which materials can be mixed or brought into contact with no reaction or separation.

A software module that analyses and converts programs from a high-level language to binary machine codes.

Any of the basic parts used in building electronic equipment, such as a resistor, capacitor, DIP or connector, etc.

The quantity of components on a unit area of printed board.

A hole in a PCB through-which a component lead passes in order to be soldered or connected mechanically to the printed circuit and electrically to the conductive pattern. Synonym: mounting hole. The hole is used for the attachment and electrical connection of component terminations, including pins and wires, to the printed board.

Primary side. The surface layer of a board on which most of the components are placed. Component side is also referred to as the top side (layer one-counting downwards) of the board.

A material to which metal particles (usually silver ) are added to increase electrical conductivity.

A thin sheet of metal that may cover one or both sides of the base material and is intended to form the conductive pattern.

The configuration or design of the conductive material on the base laminate. Includes conductors, lands, and through connections.

A single conductive path in conductive pattern. A PCB has at least one layer of conductors. Synonyms: path, trace.

The conductor width at the plane of the surface of the base material. See also: Conductor width.

The total conductive pattern formed upon one side of a single layer of base material.

The configuration or design of the conductive material on the base laminate. Includes conductors, lands, and through connections.

The side of a single-sided printed board containing the conductive pattern.

The average or minimum (as specified) distance between the adjacent edges of conductors on the same layer of a printed board.

The thickness of the conductor at any point chosen at random on the printed board, normally viewed from vertically above unless otherwise specified.

The observable width of the pertinent conductor at any point chosen at random on the printed board, normally viewed from vertically above unless otherwise specified.

The distance between the edge of a conductor and the edge of a supported or unsupported hole.

A thin dielectric cover brushed, dipped or sprayed over parts and circuits of PCBs for environmental and mechanical protection.

One plug or receptacle which can be easily joined to or separated from its mate. Multiple-contact connectors join two or more conductors with others in one mechanical assembly.

The portion of the circuit board that is used for providing electrical connections.

A protrusion of the Printed Circuit Board edge that is manufactured to a configuration to mate with a receptacle that provides electrical and/or mechanical junction between the Printed Circuit Board and other Circuitry.

The angle between the contact surfaces of two objects when bonding. The contact angle is determined by the physical and chemical properties of these two materials.

The common area between a conductor and a connector through which the flow of electricity takes place.

The electrical resistance of the metallic surfaces at their interface in the contact area under specified conditions.

The distance between the centre lines of adjacent contact areas

An impurity or foreign substance whose presence on printed wiring assemblies could electrolytically, chemically, or galvanically corrode the system.

Continuity Testing - A procedure in which voltage is applied to two interconnected lands to ascertain the presence or absence of current flow.

The matching of substrate material properties with trace dimensions and locations to create specific electric impedance as seen by a signal on the trace.

A material, usually supplied in large sheets, consisting of a base material to one or both sides of which a thin copper foil is boned. Synonym: laminate.

Quality electrolytic copper used to form conductive patterns on printed circuits. It is available in a number of weights (thickness) the traditional weights are 0.5, 1 and 2 ounces per square foot. (18, 35 and 70μm thick).

Coated copper layer on the board. It can either be characterized by weight or thickness of the coated copper layer. For instance, 0.5, 1 and 2 ounces per square foot are equivalent to 18, 35 and 70 um-thick copper layers.

A corrosivity test for fluxes in which the compound's reaction to a copper film vacuum-deposited on a glass plate is noted.

Marks placed inside the edges of PCB corners to align and register the layers.

A flux that contains corrosive chemicals such as halides, amines, inorganic or organic acids that can cause oxidation of copper or tin conductors.

Materials of inorganic acids and salts for surfaces of difficult solderability. Also called acid fluxes.

A smear or stain on the board representing flux residue after soldering and a variation from conventional appearance.

One of the patterns of the quality conformance test circuitry area.

An outer layer(s) of insulating material applied over the conductive pattern on the surface of the printed board.

A condition that makes breaks or separations in coatings that extends through to an underlying surface.

A condition existing in the base material in the form of connected white spots or "crosses" on or below the surface of the base material, reflecting the separation of fibres in the glass cloth and connecting weave intersections.

A type of connector contact whose end is a hollow cylinder that can be crimped onto a wire inserted within it.

The breaking of large conductive areas by use of a pattern of voids in the conductive material.

The formation of chemical ties between reactive atoms in the molecular chain of a plastic.

The undesirable interference caused by the coupling of energy between single paths.

The condition of a resin polymer when it is in a solid state with high molecular weight. Being insoluble and infusion.

The condition of a resin polymer when it is in the solid-state, with high molecular weight, being insoluble and infusible.

The ratio of dimensional change of an object to the original dimension when temperature changes, expressed in % / ºC or ppm / ºC.

Change of physical properties of a material via chemical reaction or heat and catalysts, usually from a liquid to a solid.

The irreversible process of polymerizing a thermosetting epoxy in a temperature-time profile.

The time needed to complete curing of an epoxy at a certain temperature.

The maximum current which can be carried continuously, under specified conditions, by a conductor without causing degradation of electrical or mechanical properties of the printed circuit board.

An unwanted break in the continuity of an electrical circuit, that prevents current from flowing.

A component placement term measuring machine speed from pick-up to board location and return.

A collection of inter-related data items stored together without redundancy to serve one or more applications.

A defined point, line, or plane used to locate the pattern of layer for manufacturing or inspection, or for both purposes.

The process of locating and fixing problems (bugs) in the hardware and software portions of an electronic system.

Any nonconformance to specified requirements by a unit or product.

The fidelity of reproduction of pattern edges, especially in a printed circuit relative to the original master pattern.

A separation between any of the layers of a base material or between the laminate and the conductive foil, or both.

Metallic filaments growing between pads and traces resulting from electromigration.

Guidelines that determine automatic conductor routing behavior with respect to specified design parameters.

The use of a computer program to perform continuity verification of all conductor routing in accordance with appropriate design rules.

The width of a conductor as delineated or noted on the master drawing. (See also: Conductor Base Width and Conductor Width).

The removal of friction-melted resin and drilling debris from a hole wall.

An individual electrical element, usually in an independent body, which cannot be further reduced without destroying its stated function.

A condition that results when molten solder has coated a surface and then receded, leaving irregularly shaped mounds separated by areas covered with a thin solder film and with the base material not exposed.

A solder coating that has receded, leaving irregular deposits and indicating that the base metal has not been adequately de-oxidized.

Kind of galvanic corrosion, generally associated with two-phase brass alloys, in which the zinc-rich beta phase is selectively leached out of the brass. It occurs when brazed joints are exposed to salt or seawater.

Dry Film Solder Mask.

Two or more dies.

The uncased and normally leadless form of an electronic component that is either active or passive, discrete or integrated.

The placement machine bonding IC chips onto a chip-on-board substrate.

The attachment of an IC chip to a substrate.

An insulating medium which occupies the region between the conductors. It is also the distance between bonded inner layer conductors.

The property of a dielectric which determines the electrostatic energy stored per unite volume for a potential gradient.

The maximum voltage that a dielectric material can withstand, under specified conditions, without rupturing (usually expressed as volts/units thickness).

A circuit comprised mostly of integrated circuits and operate, like a switch (i.e., it is either "ON" or "OFF").

A tool used to verity the design (or portions thereof) in the digital domain by applying virtual test signals to a virtual model of the design.

Any method of reducing feature locations on a flat plane to digital representation of X-Y co-ordinates.

A hole in a printed board where the means of determining location is by co-ordinate values not necessarily coinciding with the stated grid.

A measure of dimensional change cause by such factory as temperature, humidity, chemical treatment, age, or stress (usually expressed as units/unit).

Dual in-line package with two rows of leads from the base in standard spacing between the leads and row. DIP is a through-hole mounting package.

A process whereby printed boards are brought into contact with the surface of a static pool of molten solder for the purpose of soldering the entire exposed conductive pattern in one operation.

A component which has been fabricated prior to its installation (i.e., resistors, capacitors, diodes, transistors, capacitors, diodes, transistors, etc). A single function component.

A chemical added to the cleaning solution to improve its particulate-removal ability.

A solder connection that is characterized by the appearance that there was motion between the metals being joined when the solder was solidifying (not accepted).

Information on an assembly that explains the basic design concept, type and quantity of parts and materials, special manufacturing instruction, and up-to-date revisions.

A PCB with components mounted on both skies.

A printed board with a conductive pattern on both sides.

Disc Plot Format.

The making of soldered terminations by dipping the colder side of a supported printed board with through-hole mounted components into the surface of a static pool of molten solder and moving it horizontal in one direction.

A measure of cleaning solution lost via board emergence after immersion.

Design Rule Check: Checks the integrity of print (PCB) so that problems like short-circuits, unrouted nets, etc. are recognized.

Solid, carbide cutting tools designed specifically for the fast removal of material in extremely abrasive, glass-epoxy materials.

Oxide and other contaminates which form on the surface of molten solder.

Coating material in the form of laminated photo-sensitive foils specifically designed for use in the manufacture of printed circuit boards and chemically machined parts. They are resistant to various electroplating and etching processes.

Coating material specifically designed for use in the manufacture of printed circuit boards and chemically machined parts. They are suitable for all photomechanical operations and are resistant to various electroplating and etching processes.

Coating material (dry-film resist) applied to the printed circuit board via a lamination process to protect the board from solder or plating.

Within the re-flow process after pre-heat and before peak re-flow temperature wherein volatile materials escape from the solder paste.

In wave soldering, the first wave's multi-directional jet leaves solder on all contacted surfaces, followed by the second (flat) wave, which effects a finishing appearance by removing bridges and icicles. Intended for surface mount soldering.

A mechanical package without the die, used to verify placement processes.

A measurement of the hardness of a non-metal such as rubber, plastic, etc. Also the instrument for such measurement.

The distance of a pattern, components, or both, from the edges of the printed circuit board.

A connector (can be gold-plated edge contacts or a series of parallel lines of holes).

The distance of a pattern, components, or both, from the edges of the printed board and intended for mating with an edge-board connector.

A series of contacts printed on or near any edge of a printed board and intended for mating with an edge-board connector.

A layer of copper plated on to an insulating or conductive surface of a PCB by chemical reduction, that is, without the use of applied electrical current.

The deposition of conductive material from an auto-catalytic plating solution without application of electrical current.

Terminations made by heating with a stream of electrons in a vacuum.

The electrodeposition of a metal coating on a conductive object. The object to be plated is placed in an electrolyte and connected to the relative terminal of a dc voltage source. The metal to be deposited is similarly immersed and connected to the positive terminal. Ions of the metal provide transfer to metal as they make up the current flow between the electrodes.

A discrete component that is fabricated as an integral part of a printed board.

The side of the film on which the photographic image is defined.

The damaging admission and trapping of air, flux and fumes; it is caused by contamination and plating.

A family of thermosetting resins used in the packaging of semiconductor devices. Epoxies form a chemical bond to many metal surfaces.

Materials that form straight chain thermoplastic and thermosetting resins having good mechanical properties and dimensional stability.

Epoxy resins which has been deposited onto the surface or edges of the conductive pattern during drilling. Also called resin smear.

Epoxy Resin Bonded Glass Fibre (See FR4).

Electrical Rule Check: checks the integrity of a circuit (SCH) so that problems like open inputs, shorted outputs and much more are recognized.

The percentage of defects not defected vs. the total inspected.

Electro-Static-Discharge, the sudden transfer or discharge of electricity from one object to another.

The device's ability to dissipate the energy of the discharge or withstand the current levels involved.

Electro-statically applied Solder Resist.

The ratio of the depth of etch (conductor thickness) to the amount of lateral etch (undercut).

An organic ink, lacquer, photo-resist, self-adhesive plastic tape, metal deposit or other material which will prevent specific areas of the metal on a panel from being attacked by an etchant.

A solution used to remove, by chemical reaction, the unwanted portion of material from a printed board.

The controlled removal of all components of the base material by a chemical process acting on the sidewalls of plated-through holes to expose additional internal conductor areas.

The controlled removal of all resins of base material on the side wall of holes in order to expose internal conductor areas.

A board having a conductive pattern formed by the chemical removal of unwanted portions of the conductive foil.

Removal of metal from the surface of PCB by chemical dissolution. The process is normally carried out selectively by masking areas of metal which are to be left on the PCB.

The characteristic curve of a resin during cure showing reaction of temperature vs. time.

Unwanted copper remaining on the base material after chemical processing.

A hollow tube inserted in a terminal or printed board to provide mechanical support for component leads or electrical connection.

A listing of shorts and opens on a PCB to be repaired.

A plated through-hole in a printed circuit board that is used to provide electrical connection between a trace on one side of the printed circuit board to a trace on the other side. Since it is not used to mount component leads, it is generally a small hole and pad diameter.

A condition in which broken reinforcing fibres of the base material are exposed and protrude in machined or abraded areas.

Flashscan Image Control Software: A DOS Program which sends Gerber files to the plotter.

A mark both in the artwork and etched with the circuit traces of the PCB. It is used to identify artwork orientation on the board. Global fiducials locate the overall pattern; local fiducials pinpoint component sites, typically fine-pitch.

The concave formation of soldified solder between the land or pad and the component lead.

Printed circuit design permitting two, and nowadays even three, traces between adjacent dip Pins. It entails the use of photo-imageable solder mask (PISM).

Fine pitch is more commonly referred to surface-mount components with a lead pitch of 25 mils or less.

A gold-plated terminal of a card-edge connector. Also see Gold Finger.

A sample part or assembly manufactured prior to the start of production for the purpose of assuring that the manufacturer is capable of producing a product that will meet specified requirements.

The per centage of finished assemblies to pass all tests without re-work.

A device that enables interfacing a printed circuit board with a spring-contact probe test pattern.

A cable with two or more parallel, round or flat, conductors in the same plane encapsulated by an insulating material.

A random arrangement of printed wiring utilizing flexible base material with or without flexible cover layers.

A conductor failure due to repeated flexing which is indicated by an increase of resistance to a specified value for a specified time.

A device on a screen printer that drags solder paste back to the starting point after the squeegee has made a stroke. The return is for set-up of the next stroke as it does no printing on the backstroke.

Also called wave soldering. A method of soldering printed circuit boards by moving them over a flowing wave of molten solder in a solder bath.

An organic compound having fluorine atoms in its structure to lend chemical and thermal stability to plastics.

A conductor whose outer surface is in the same plane as the surface of the insulating material adjacent to the conductor.

A substance used to promote or facilitate fusion, such as a material used to remove oxides from surfaces to be joined by soldering welding.

A flux-related contaminant that is present on or near the surface after soldering and, if possible, should be washed away.

A wire of solder that contains one or more continuous flux-filled cavities along its length.

A thin sheet of metal, usually copper, used as the conductor for printed circuits.

A set of properly sized and placed pads of a PCB on which a surface mounted component can be placed and soldered. Alternatively, the footprint is the board area occupied by a surface mounted component and its mounting pads. See also Land Pattern.

Convection, consisting of flow, rate, velocity and temperature, as heat transfer of fluid or gas over solder joints to be re-flowed.

Flame retardent laminate made from woven glass fibre material impregnated with epoxy resin.

An additive process wherein the entire thickness of electrically isolated conductors is built-up by copper.

To check an assembly using equipment that tests for the functions intended and engaging inputs and outputs.

A metallic coating, usually tin or solder alluvia, which has been melted and solidified forming a metallurgical bond

A flowing inert gas atmosphere used to keep metal from oxidizing.

Vector-based language, developed by Gerber Scientific Instrument Company, for sending commands to photoplotters.

Laminate made from woven glass fibre material impregnated with polyimide resin.