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PCB Index

A | B | C | D | E | F | H | I | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Z

A

Activating
A treatment that modifies non-conductive material responsive to electroless plating.

Additive Process
Careful deposition or addition of conductive material onto clad or unclad base material.

Ambient
The surrounding area making contact with the system or component in query.

Analog Circuit
An electrical circuit with a continual variable signal.

Annular Ring
The area of conductive material entirely encompassing a hole.

Automated Optical Inspection (AOI)
Automatic laser/video inspection of traces and pads on a circuit board by utilizing a machine scanner to assess the quality of manufacture. Used in finding open traces or design flaws.

Acceptance Quality Level (AQL)
Refers to the defective maximum limit likely to occur in a production lot, that is still deemed contractually acceptable, usually associated with a statistically derived sampling plan.

Aperture Information
A text file, also referred to as a D-Code List, that describes the size and shape of each element on a printed circuit board. Aperture Information is not necessary if you are generating RS274X extended gerber files with embedded Apertures.

Array
Printed circuit boards arranged in rows and columns on a base material. Also referred to as a panel.

Array Up
The number of distinct PCB's in the array (panel) configuration.

Array X Dimension
The outermost array measurement on the X axis incorporating any rails or borders, measured in inches.

Array Y Dimension
The outermost array measurement on the Y axis incorporating any rails or borders, measured in inches.

Artwork
A precisely scaled configuration used to create the artwork or production master.

Artwork Master
The photographic film or glass plate which illustrates the image of a PCB pattern, normally on a 1:1 scale.

AS9100
A standardized quality management system specifically designed for the aviation, aerospace, and defense industry, and those vendors who supply them.

Aspect Ratio
The ratio of the printed circuit board thickness to the diameter of the smallest hole.

Assembly
A specific number of parts, sub-assemblies, or any combination joined together.

Assembly File
An image that describes the positioning of components on a circuit board.

Assembly House
A service facility that handles the soldering and attaching components to a printed circuit board. Also known as Electronic Manufacturing Services.

Automated Test Equipment (ATE)
Test equipment that automatically assesses functional or static parameters in order to grade product performance.

B

B-Stage
The mid-level process in the reaction of a thermosetting resin where the heated material softens and expands, but does not dissolve, when it comes in contact with certain liquids.

B-stage Material
A sheet of material impregnated with a resin cured to an intermediate stage (B-Stage Resin). Also referred to as prepreg.

B-Stage Resin
A thermosetting resin at a mid-level state of the curing process.

Back Drilling
The process of disposing the unused portion of vias by drilling a larger hole from one or both sides after plating. This is normally required in very high speed applications.

Back-Up Material
A layer made up of phenolic, paper composite, or aluminum foil-clad fiber composite used during fabrication to protect the drill table and prevent burrs.

Barrel
The cylinder created from plating the interior walls of a drilled hole.

Bare Board
A printed circuit board with conductors but without any components installed. Also referred to as an unpopulated or unassembled PCB.

Base Copper
The thin, copper foil area of a copper-clad laminate, present on either one side or both sides of the board.

Base Material
The insulating material used in the process of creating a conductive outline. It can be either rigid, flexible, or both.

Base Material Thickness
The thickness of the base material omitting metal foil or any deposited material on the surface.

Bed of Nails
A test fixture consisting of a frame and a holder which contains a field of spring-loaded pins that make electrical contact with the product being tested.

Bevel
A printed circuit board with an angled edge. Also referred to as a beveled edge.

Bleeding
A situation in which a plated hole excretes process materials of solutions from voids and crevices.

Blind Via
A conductive surface hole, that is a bridge between only one external layer and one or more internal layers of a multi-layer PCB.

Blister
A confined swelling and/or separation between any of the layers of a laminated base material, or between base material and conductive foil. A form of delamination.

Board House
A PCB manufacturer, source, supplier, or vendor.

Board Thickness
The overall thickness of the base material along with metal foil and any material deposited on the surface.

Book
A determined number of stacks of prepeg plies that are put together with the inner layer cores for curing in a lamination press.

Bond Strength
The force per unit necessary to split two adjacent layers of a board by a force perpendicular to the board surface.

Bottom SMD pads
The total number of surface mount device pads on bottom.

Bow
The unevenness of a board characterized by roughly a cylindrical or spherical curvature such that, if the board is a rectangle, its four corners are in the same plane.

Border Area
The area of a base material that is external to that of the final product being fabricated within it.

Build Time
Manufacturing time required to produce a product.

Built In Self Test
The ways by which a machine tests itself.

Buried Via
A copper plated hole, that interconnects one or more internal layers, but does not connect to an external layer of a multi-layer PCB.

Burr
A ridge or raised area left on the outside copper surface after drilling.

C

C-Stage Resin
A resin in its last state of the curing process.

Computer Aided Design (CAD)
Computer software used by engineers to create a design (i.e. printed circuit board layout) and review the proposed product on a computer screen or in the form of a printout or plot.

Computer Aided Manufacturing (CAM)
Is the use of computer software to control related equipment and machine tools in the manufacturing process.

CAM Files
The design files used directly in the manufacture of printed circuit boards. They are as follows: 1. Gerber Files, 2. NC Drill File, 3. Fabrication Drawing located in the gerber or any other electronic format.

Card
In electronics, another term for a printed circuit board.

Capacitance
The property of a system that enables the storage of electricity when possible differences exist between the conductors.

Castellated Holes
Are plated or non-plated vias or thru holes that are cut through to create a partial or half hole for the purpose of creating an opening into the side of the hole barrel.

Catalyst
A substance that is used to create a reaction or increase the rate of speed between a resin and a curing agent.

Cavity Process
Process that permits portions on the inner-layers to be visible.

Center To Center Spacing
The distance between the centers of any side-by-side features on any single layer of a printed circuit board.

Chamfer
A broken corner to remove an otherwise sharp edged corner.

Check Plots
Pen plots, or plotted film that are suitable for examining and for customer design approval.

Computer Integrated Manufacturing (CIM)
Software that acquires assembly data from a CAD or CAM program and using a pre-determined factory modeling system, outputs routing of components to machine programming destinations and assembly and inspection documentation.

Circuitry Layer
A layer on a PCB which contains conductors, including ground and voltage planes.

Circuits
A interconnected group of electrical devices and elements that have been manufactured to perform a desired electrical function.

Clad
A copper object on a printed circuit board.

Class 3
Highly reliable electronic products designed for continued operation or performance.

Cleanroom
A room that has controlled concentration of airborne particles.

Clearance Hole
A hole located within the conductive pattern which is larger and coaxial with a hole in the base material of a printed circuit board.

Clearances
The space from a power or ground layer to a plated through hole.

CNC
An approach that uses a computer and software program as the principal numerical control technique.

Coating
A layer of material which is deposited on the surface of PCB.

Chip On Board (COB)
The direct addition of a chip to a PCB by solder or other various adhesives.

Component
An electronic device, usually a resistor, capacitor, inductor, or integrated circuit. That is mounted to a circuit board and performs a specific electrical operation.

Component Hole
A hole that is used to join and electrically connect component terminations(including pins or wires) to a PCB.

Component Side
The side of a PCB where most of the components are situated. Also referred to as the "top side".

Computer Numeric Control
An approach that uses a computer and software program as the principal numerical control technique.

Conductive Pattern
The configuration pattern or design of the conductive material located on a base material.

Conductor
A thin conductive area on the PCB surface or inner-layer of a circuit board usually made up of lands and paths. Also known as a "Line".

Conductor Spacing
The visible space between adjacent edges, of isolated conductive patterns in a conductor layer.

Continuity
An undisturbed path for the flow of electrical current throughout a circuit.

Continuous Outline
The outline or cut line for a PCB created from a single continuous line.

Conformal Coating
An insulating & protective coating which conforms to the configuration of the coated object and is applied on the final board assembly.

Connection
A single leg of a net.

Connector
A plug or receptacle, that can be easily attached to or be separated from its mate.

Connector Area
The area of the circuit board which is used for allowing electrical connections.

Controlled Depth Drilling
The process of drilling only part way through the board thickness.

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

Controlled Dielectric
Specified thickness of the insulation layers amongst a signal and power or ground planes.

Copper Foil
The layer of copper coating on a circuit board.

Copper Weight (Inner)
The copper thickness required on inner layer cores, usually 1 oz.

Copper Weight (Outer)
The number of ounces of copper per sq./ft. on the outer layers. Designate this as "finished" copper weight.

Cores <.004
A general requirement in controlled dielectric or controlled impedance apps. For cores that are < .004. These could possibly require special handling and processing.

Core Thickness
The thickness of the laminate base not including copper.

Corrosive Flux
A corrosive discharge that has reactive materials in it and can cause damage by oxidation.

Counterbore
A cylindrical recess, machined around a hole to permit a screw head to sit flush with a surface.

Countersink
A beveled recess, machined around a hole to permit a screw head to sit flush with a surface.

Cover Coat
A layer of dielectric that covers the surface of the board. This can be used when the boards need insulation from adjacent conductive surfaces or in extremely high voltage applications

Crosshatching
The condition of breaking up a conductive portion of the board through voids in the conductive material.

Coefficient Of Thermal Expansion (CTE)
The measurement amount of how much a material changes in any axis per degree of temperature adjustment.

CTI
The voltage that causes tracking after 50 drops of .1% ammonium chloride solution have fallen onto the material.

Curing
The act of applying heat and pressure to a material in order to secure a bond.

Curing Time
The amount of time needed for an epoxy to cure.

Customer Part Number
A unique number assigned to a customer that is placed on a board.

Cut Lines
The outside edge of a circuit board that is used to program the router path. The tolerance on route dimension is +/-.010. it is advisable to keep outer layer copper.010 and inner copper .020, from the cut line to avoid exposing copper at the board edge.

D

Data Base
A collection of related data stored together on a computer to serve one or more applications.

Date Code
A marking that indicates the products date of manufacture, usually week and year (WW-YY).

Datum Point
Any reference point of known or assumed coordinates from which calculation or measurements may be taken from.

Deburring
The removal of burrs after the drilling process.

Defect
A nonconformance to a specified set of requirements by a unit or product.

Definition
The conformity and sharpness of reproduction of a PCB's pattern edges as compared to the original pattern.

Delamination
A separation amongst layers of the base laminate or between the laminate and the conductive foil or plane on a PCB.

Design Rule
A list of guidelines for a circuits design in accordance to the specified design parameters.

Design Rule Checking
The use of a computer-aided software program to perform continuity authentication of conductor routing in accordance with the specified design parameters.

Desmear
The removal of friction-melted resin and drilling remains from the walls of a hole on a PCB.

Dewetting
A condition that results when molten solder has coated a surface and then retreats. It produces areas of unevenly shaped mounds separated by areas of thin solder film with the base material not exposed.

Dielectric
A insulating material between two conductors that has a high resistance to the flow current.

Digitizing
The converting of feature areas on a flat plane to a digital diagram in X-Y coordinates.

Dimensional Stability
A measure of the dimensional change of a material that is instigated by factors such as temperature & humidity changes, chemical exposure or treatment, and the exposure to stress.

Dimensioned Hole
A hole in the PCB whose position is determined by physical dimensions or coordinates that do not necessarily have to agree with the stated grid.

Document Retention
The standard time period quality control documents are retained on file.

Double Sided Assembly
A assembled PCB with components on both of its sides.

Double Sided Board
A PCB with a conductive pattern on both of its sides. Also referred to as a 2-layer board.

Drawing Or Print
A paper drawing used to aid in the construction of a PCB. It shows all the parameters of the holes to be drilled, sizes, and tolerances, dimensions of the board, and specifications of the materials and methods to be used for production. Often sent electronically in PDF format to the PCB manufacturer.

Drill File
Electronic data created from the computer-aided design software used for programming the CNC drilling and routing machines. This file specifies the finished hole sizes and locations.

Drill Tool Description
Text files specifying drill tool number, corresponding size, quantity, and which holes are plated thru-holes (PTH) and non-plated thru-holes (NPTH).

Dry Film Resists
A coating material designed specifically for the manufacture of PCBs which is resistant to several different electroplating and etching processes.

Dry Film Solder Mask
A solder mask film applied to the PCB through a photographic method to shield the board from solder or plating.

Dual Inline Packaging (DIP)
A type of housing used for integrated circuits (IC's).

E

Edge Clearance
The shortest space between any component or conductor to the PCB's edge.

Edge Connector
A connector on the edge of a PCB which enables the board to connect to another electronic device.

Electrical Continuity
The constant flow of electrical current.

Electrical Test
A test that checks for opens and shorts. Also known as bare board testing.

Electro Deposition
The deposition of a conductive material from a plating solution by using electrical current. Also see electroplating.

Electroless Copper
A thin layer of copper deposited on the plastic or metallic surface of a PCB from a autocatalytic plating solution without electrical current.

Electroless Deposition
The deposition of conductible material from an autocatalytic plating solution without electrical current.

Electroplating
Using electrical current for the deposition of adherent metal coating on a conductive object.

Electroplated Hard Gold
A RoHS compliant surface finish thicker and harder than immersion gold making it ideal for edge-connector contacts for PCBs that are repeatedly plugged in and removed.

Embedded Traces
A conductive line that is surrounded by ground fill.

Electroless Nickel Immersion Gold (ENIG)
A high performance RoHS compatible surface finish designed to deliver a highly corrosion resistant and superior solderable surface. Shelf life is approximately 12 months.

Entry Material
A thin layer of material made up of phenolic, aluminum foil, or paper that is secured on top of a panel before drilling. It's used for drill accuracy and to prevent burrs and dents.

Epoxy
Thermosetting resins that create a chemical bond to several metal surfaces.

Epoxy Smear
An undesirable epoxy resin that has been deposited on the edges of copper holes throughout the drilling process.

Etchback
The controlled elimination of all components of the base material by a chemical process acting on the sidewalls of PTHs to expose additional internal conductor areas.

Etching
The chemical, or chemical and electrolytic removal of unwanted areas of conductive material.

Excellon Drill File
The Excellon format was designed for and is primarily used to drive NC drill and rout machines. It is suitable for that task as it can specify machine specific information such as drill feed and speed.

F

Fab
Abbreviation for Fabrication.

Fabrication Drawing
A drawing used as a construction aid for a printed circuit board.

Feed-Thru
Also know as a "Via", a plated through hole used as a means for a inner-layer connection between conductors on one layer and conductors on another layer.

Fiducial Mark
A printed board feature or features that are created to provide a common measurable point for component mounting with respect to a pad pattern or pad patterns.

Files: Gerber
Is the industry standard file format that is used by the photoplotter to describe the printed circuit board design.

Fine Pitch
More commonly referred to surface-mount components with lead pitches of 25 mils or less.

Finger
A gold-plated connection point on a PCB edge connector.

First Article
A sample part usually manufactured before the start of production for the sole purpose of ensuring that the manufacturer is capable of making a product that meets the customer's design specifications.

Flex
A patterned arrangement of printed circuitry and components which uses flexible base material with or without a flexible cover lay.

Flux
A material which is used to remove oxides from metal surfaces and allow wetting of metal with solder.

Flying Probe
A bare board testing machine that uses probes on the ends of mechanical arms to locate and contact the pads on the board. The probes move quickly across the board verifying continuity of each net as well as resistance to adjacent nets.

Footprint
The size and shape of the pads used in the soldering of electronic components.

FR-1
A paper material with a phenolic resin binding agent. FR-1 has a glass transition temperature(Tg) of about 130 Celsius.

FR-2
A paper material with phenolic resin binding agent that is similar to FR-1. The glass transition temperature(Tg) is usually about 105 degrees Celsius.

FR-3
Used mostly in Europe, FR-3 is a paper material that is relatively similar to FR-2 except that an epoxy resin is used instead of a phenolic resin as a binding agent.

FR-4
Flame retardant, woven glass material strengthened with epoxy resin. FR-4 is the most common dielectric material used in PCB construction.

H

Hot Air Solder Leveling (HASL)
A process of coating exposed copper with solder by placing a panel into a bath of molten solder then passing it through a high pressure stream of hot air.

High Density Interconnect (HDI)
Ultra fine-geometry multi-layer printed circuit boards made up of conductive microvia connections. They often include buried and/or blind vias.

Hermetic
Referring to airtight sealing.

Hole Breakout
A condition in which a hole is partially encompassed by the land .

Hole Density
The amount of holes in a unit area of a PCB.

Hole Pattern
The arrangement of every given hole on a PCB with respect to a reference point.

I

Imaging
The method of moving electronic data to the photo-plotter, which in turn uses light to transfer a negative image circuitry pattern onto the panel or film.

Immersion Plating
The chemical deposition of a thin metallic coating over specific basis metals through the partial displacement of the basis metal.

Immersion Gold (ImAu)
A high performance RoHS compatible surface finish designed to deliver a highly corrosion resistant and superior solderable surface. Shelf life is approximately 12 months. Also referred to as ENIG.

Immersion Silver (ImAg)
A high performance RoHS compatible surface finish usually less expensive than Immersion Gold. Shelf life is approximately 12 months.

Immersion Tin (ImSn)
A RoHS compatible surface finish usually less expensive than Immersion Gold and Silver. Shelf life is approximately 6 months.

Impedance
A materials resistance to the flow of an electrical current. The unit of measure is ohms. Usually used to describe high-frequency PCBs.

In-Circuit Test (ICT)
Is where an electrical probe tests an assembled PCB, checking for shorts, opens, resistance and capacitance to ensure the assembly the manufactured correctly. A bed of nails type test fixture and specialized test equipment or fixtureless in-circuit test setup is used.

Inclusions
Foreign particles/debris that are possibly entrapped in an insulating material, conductive layer, plating, base material, or solder connection.

Individual Route
Cutting the PCB to match the outline layer specified in the design files, usually gerber files, sent by the customer.

Inkjetting
The placement of well defined ink "dots" onto a PCB.

Inner Layers
The internal layers of a multi-layer PCB.

Insulation Resistance
The electrical resistance of an insulating material that is determined under specific conditions amongst any pair of contact, conductors, or grounding devices in diverse combinations.

Interconnect Stress Test (IST)
A test that measures the capability of the complete interconnect to tolerate the thermal and mechanical strains from the manufactured state to the point at which the product reaches interconnect failure.

Internal Power and Ground Layers
Generally are the solid copper planes of a multilayer PCB attached to power or ground.

Internal Signal Layers
Routing layers made of signal traces that are confined below the surface layers.

Institute for Interconnecting & Packaging Electronic Circuits (IPC)
The final US authority on how to design and manufacture printed wiring.

Interstitial Via Hole
A embedded through-hole that has connection of two or more layers in a multi-layer PCB.

K

Known Good Board (KGB)
Also known as a "Golden Board", a printed circuit board that is free of all defects and meets all the customer's design & build specifications.

L

Laminate
The plastic material generally reinforced by glass or paper that supports the copper cladding from which PCB traces are created.

Laminate Thickness
The thickness of the metal-clad base material, single-or double-sided, before any processing.

Laminate Void
Any cross-sectional area without epoxy resin where it normally should exist.

Land
The section of the conductive pattern on PCBs allocated for the mounting of components. Also known as PAD.

Laser Photo-plotter
A plotter that utilizes a laser to create a raster image of individual objects in a CAD database, that marks the image as a series of lines of dots at a very detailed resolution. More accurate than a vector plotter.

Layers
The number of conductive layers in a PCB.

Layer Sequence
The sequence of layers in a circuit board design.

Layup
The method in which treated prepregs and copper foils are assembled for pressing.

Lead
A terminal located on a electronic component.

Leakage Current
The minimal amount of current that flows over a dielectric area between two side-by-side conductors.

Legend
Lettering or symbols on a printed circuit board (i.e., part #, serial #, component locations, patterns, logos). Also known as the silkscreen.

Line
A thin conductive area on a PCB surface area or inner-layer usually made up of lands and paths. Also known as "conductor".

Lot
A quantity of circuit boards that built to the same design specifications and come from the same production batch.

Lot Code
A date code placed on a specific production quantity of boards (production lot) for tracking purposes. It shows they were all manufactured at the same time.

Liquid Photo-Imageable Solder Mask (LPI)
A certain type of ink created using photographic imagining techniques to control deposition. Because of its accuracy it is the preferred method of mask application.

M

Major Defect
A defect that is likely to cause failure of a unit or product.

Mask
A material applied to allow selective etching, plating, or the application of solder to a PCB. Also known as soldermask or photo resist.

Measling
Discrete white spots or crosses underneath the surface of the base laminate that reflect a separation of fibers in the glass cloth at the weave junction.

Metal Foil
The layer of conductive material where circuits are created. Metal foil is usually copper and is available in sheets or rolls.

Micro-Sectioning
The preparation of a specimen to be used in metallographic examination. This usually consists of cutting out a cross-section of a PCB and encapsulating it.

Microvia
Typically defined as a conductive hole with a diameter of 0.005" or less that connect layers of a multi-layer PCB.

Mil
A unit of measure that equals one thousandth of an inch.

Minimum Conductor Width
The minimum width of any conductor on a PCB.

Minimum Conductor Space
The shortest distance between any two conductors on a PCB.

Minor Defect
A defect which is unlikely to cause failure of a unit or product and does not downgrade its usability for its intended purpose.

Mounting Hole
A hole that is used for the mechanical backing of a printed board or for the mechanical attachment of components to a printed board.

Multi-Layer PCB
Printed circuit boards with 3 or more conducting circuit planes separated by insulating material and bonded together into relatively thin homogeneous constructions with internal and external connections to each level of the circuitry as needed.

N

Numeric Control Drill Machine (NC Drill)
A machine that is used to drill holes in a PCB at precise locations, which are specified in a data file, usually located in the gerbers.

Negative
The reverse copy of a positive image, useful for examining revisions of a PCB and is commonly used for representing inner layer planes.

Net
A compilation of terminals which are, or have to be, linked electrically. Also referred to as a signal.

Netlist
A list of names of parts or symbols and their connection points in each net of a circuit. A netlist is generated from schematic-drawing files of an electrical CAE application.

Node
A pin or lead in which two or more components are connected by conductors.

Nomenclature
Identifying letters or symbols marked on a board by means of screen printing, inkjetting, or a laser process.

Non-Plated Through Hole (NPTH)
A hole on a PCB without plated copper on its walls, also called a non-supported hole.

Non-Recurring Expense (NRE)
The cost of creating a new product, which is paid up front (i.e. cost of design, cost of tooling, and the cost of films.)

O

Open
Referring to open circuit. A unwanted break in the continuity of an electrical circuit which stops the flow of current.

Organic Solder Preservative (OSP)
Used as a surface finish to form a thin, uniform, protective layer on the copper surface of a PCB.

Outer-Layer
The top and bottom layers of a PCB.

P

PAD
The section of the conductive pattern on PCBs allocated for the mounting of components. Also known as a land.

Panel
A rectangular sheet of base material or metal-clad material, normally FR-4, of a predetermined size that is used in the fabrication of PCBs.

Part Number
The name or number designated to a customer's PCB design.

Pattern
The configuration of conductive and nonconductive materials on a panel or on a PCB. Also, the circuit configuration on similar tools, drawings, and masters.

Pattern Plating
A term used for the selective plating of a conductive pattern.

Pb-Free HASL
A RoHS compatible surface finish usually less expensive than Immersion Gold and Silver. Shelf life is approximately 12 months.

Printed Circuit Board (PCB)
A flat base of insulating material that is used to give support as well as provide electrical connections for electronic components. Also known as a printed wiring board (PWB).

Photographic Image
An image which is in a photo mask or in a emulsion that is on a film or plate.

Photo Plotter
A device that is used to produce a image by plotting objects onto film for use in the manufacturing of PCBs.

Photo Print
The process of producing a circuit pattern image by dispatching light through a photographic film that hardens a photosensitive polymerizing material.

Photo Resist
A material applied to allow selective etching, plating, or the application of solder to a PCB. Also known as soldermask.

Photo Tool
Clear film that contains the circuit pattern, that is represented by a series of dots and lines at a high resolution.

Pin
A connection point (terminal) on a component. Also known as a lead.

Pitch
The center-to-center space of any two adjacent conductors on a PCB.

Platen
A flat plate of metal located in the lamination press in between which stacks are placed during the press process.

Plating
The chemical or electrochemical metal deposited on a surface.

Plating Resist
A material placed on a area to prevent plating from occurring.

Plating Void
The absence of a specific metal from a particular cross-sectional area.

Plated-Through Hole (PTH)
A hole that has been plated on its walls which produces an electrical connection between inner-layers, external layers, or both.

Plotting
The mechanical conversion of X-Y coordinates into a visual pattern such as artwork.

Positive
A developed image of a photo-plotted file. The areas selected to be exposed by the plotter appear black and the areas not exposed are clear. For outer-layers, color indicates copper. Positive inner-layers will have clear areas which indicate copper.

Prepreg
Sheet material impregnated with resin cured to an intermediate state (B-Stage Resin). Sometimes referred to as B-Stage Material.

Pressing
The process by which a combination of heat and pressure are applied to prepreg and copper foil which creates fully cured laminated sheets.

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

Printed Wiring Board
A board of insulating material that is used to give support as well as provide electrical connections for electronic components. Also known as a printed circuit board (PCB).

Probe Test
A spring-loaded metal device used to make electrical connection between the test equipment and the PCB being tested.

Prototype
A sample PCB used to test the design before other PCBs are manufactured.

Pulse Plating
A plating process that uses pulses instead of direct current.

Q

Quantity
The amount or number of a material or immaterial thing.

R

ReadMe File
A text file usually included in the gerber zip file providing the designer's contact information and other information that is needed to manufacture a customer's order.

Reflow
The process of melting down electrodeposited tin/lead followed by solidification.

Reference Designator
The name or identification mark, usually in white or yellow silkscreen, for component locations on a PCB normally starting with one or two letters preceded by a numeric value.

Reference Dimension
A dimension for informational purposes that doesn't govern inspection or other manufacturing processes. These normally do not have tolerances.

Registration
The degree of conformity of a pattern to its planned position on a product.

Resin (Epoxy) Smear
Resin that has been moved from the base material onto the surface of the conductive pattern in the wall of drilled hole.

Resist
A material applied to allow selective etching, plating, or the application of solder to a PCB. Also known as soldermask.

Revision
The number of changes to a part number before it has reached the current level of development.

Rigid-Flex
A type of circuit board that combines both flexible and rigid dielectric materials in assembly.

Rogers Material 4350
A material that is becoming extremely common due to the growth of the wireless industry. It is used in nearly all radio frequency (RF) devices. It has an impressive and efficient dilectric constant and allows for very little current impedance.

RoHS
Also known as Directive 2002/95/EC, RoHS is the acronym for Restriction of Hazardous Substances. It originated in the European Union and restricts the use of certain hazardous materials found in electrical and electronic products. All applicable products in the European Union market after July 1, 2006 must pass RoHS compliance.

Rout
The miling of a PCB. The term is also used for the layout or wiring of a connection, or the action of producing such a wiring.

Router
A machine the cuts away portions of laminate to create the desired size and shape of a PCB.

Routing
The process by which electrical connections are made between pads.

S

Schematic
A diagram with graphic symbols that shows electrical connections and functions of a specific circuit layout.

Scoring
A method in which grooves are machined on opposite sides of a panel to a depth that allows individual boards to be separated from the panel after component assembly.

Screen Printing
A process for transferring an photo to a surface by forcing media through a stencil screen with a squeegee.

Short
An abnormal connection of fairly low resistance between two points of a circuit. This results in excess current that is often damaging between these points.

Silkscreen
Reference decals and designators on a PCB used to identify the location of components during the assembly and troubleshooting processes. The epoxy ink is "squeegeed" through a silk screen and can be placed on one or two sides of the PCB depending on the design and application.

Solder Mask Over Bare Copper (SMOBC)
A method of fabricating a PCB that results in final metallization being copper with no protective metal. The non-coated areas are covered by soldermask, leaving only the component terminal portion exposed. This prevents tin lead under the mask.

Surface Mount Device (SMD)
Components that do not have leads that go thru the PCB. They are soldered to the PCB without the need of plated-thru holes.

Surface Mount Technology (SMT)
Components are soldered to the PCB without the use of plated-thru holes. The end result is increased component density which allows for smaller PCBs.

Single Sided Board
A printed circuit board with only one conductive side.

Smallest Hole
The smallest drilled hole in a design.

Small Outline Integrated Circuit (SOIC)
A kind of integrated circuit that has two parallel rows of pins in surface mount package.

Solder
An alloy that melts at fairly low temperatures and is used to bring together or seal metals with higher melting points. It has a melting temperature below 800°F (427°C).

Solder Bridging
A misconnecting solder connection that joins two or more pads to form a conductive path. Normally solder bridging creates defects in the product.

Solder Coat
A layer of molten solder applied to a conductive pattern.

Solder Leveling
A process where excess solder is removed from holes and lands of a board by being exposed to hot oil or hot air .

Solder Mask
A method of coating everything on a circuit board with a mask except the contacts to be soldered, the gold plated terminals of any card-edge connectors, and any fiducial marks.

Statistical Process Control (SPC)
The collection of process data and creation of control charting used to oversee stability.

Stencil
A tool used to transfer solder paste to a bare PCB.

Step-And-Repeat
A method by which successive exposures of a single image are created to make a multiple image production master.

Stripping
A chemical process of removing imaging material from a panel during fabrication.

Stuff
Attaching components and soldering them to a PCB.

Sub-Panel
A collection of different PCBs arrayed in a panel and processed by the board and assembly house as though it were a single printed wiring board.

Substrate
A material whose surface adhesive is spread on for bonding or coating. It is also used to separate the circuitry on a PCB.

Subtractive Processing
The technique of selectively removing copper from a board to create a circuit.

Surface Mount Pitch
The pitch of the surface mount is defined as the measurement in inches from center to center of surface mount pads.

T

Tab Routing
A method of creating a vast number of printed circuit boards for automated assembly, using a routing bit. A routing path is formed around the exterior of the board, leaving a narrow tab of material attaching the PCBs to each other and to the panel border.

Tented Via
A type of via containing a dry film solder mask entirely covering its pad and plated through holes, therefore protecting against accidental shorts, but it also renders the via unusable as a test point.

Tenting
The process of covering the holes in a printed board and the conductive pattern surrounding the holes with a dry film resist.

Terminal
A connection point for two or more conductors in an electrical circuit, usually one is an electrical contact or lead of component.

Test Board
A PCB that is believed to be acceptable for deciding whether or not a group of boards will be manufactured with the same fabrication process.

Test Coupon
The part of a printed circuit board or panel which holds printed coupons that are used to test the suitability of the board.

Test Fixture
The interface device that joins the testing equipment and the item being tested.

Test Point
A predetermined point used to see whether the quality of a circuit board is acceptable.

Glass Transition Temperature (Tg)
The point at which the temperature has caused the resin located inside the laminated base to soften into a substance similar to plastic.

Thief
The use of an extra cathode to divert to itself some of the current from areas of the board which otherwise would get high a current density.

Thru-Hole (TH)
The use of pins intended to be inserted into holes and soldered to the pads of a printed board.

Tolerances
The variation allowed in a measurement or specified quantity.

Tooling
The associated costs and the process of setting up the manufacturing of a printed circuit.

Tooling Holes
The term used to describe that holes strategically placed on the PCB for registration and hold-down purposes.

Top Side
The side of the PCB where the components are located.

Trace
The wiring that permits an electrical connection.

Track
The wiring that permits an electrical connection.

Traveler
The instructions detailing the processing requirements of a PCB.

Twist
A defect in the laminate which causes a deviation in the planarity and results in a twisted arc.

U

Underwriter's Laboratories, Inc. (UL)
An organization that uses Underwriters to test and certify the safety standards of PCB components and equipment.

Unclad
Cured epoxy glass that does not contain copper layers.

Underwriter's Symbol
The Underwriters Laboratories Inc. logo applied to products that have been approved.

Unshielded
A circuit that is exposed to electromagnetic and radio-frequency interference.

UV Curing
The use of ultra-violet light as a source of energy during the polymerization of a resin material.

V

Via
A plated through hole used as a means for an inter-layer connection between conductors routed vertically in the PCB.

Void
The lack of any substances in a specified area.

V-Scoring
A method used for "scoring" the edges of a board, which creates two beveled lines along the perimeter of the board, making it easier to break apart at a later date.

W

Wave Soldering
The process of placing assembled PCBs in contact with a constantly flowing and circulating mass of solder, usually in a bath whereby the hole pads and barriers are connected by leads.

Wicking
The constant movement of copper salts into the glass fibers of an insulating material located in the barrel of a plated hole.

WIP
Abbreviation for Work-in-progress.

Wire
The transmission of electric current through a protected strand of conductive metal.

X

X-Axis
In a two dimensional system of coordinate, this is the horizontal axis that goes left to right.

Y-Axis
In a two dimensional system of coordinate, this is the vertical axis that goes bottom to top.

Z

Z-Axis
The axis that is perpendicular to the plane which is formed by the X & Y datum reference and within the circuit boards it represents the thickness.

Zip File
A compressed computer file used for storage or transmission of one or more files.

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