Printed
Circuit Board manufacture employs specific terminology
and acronyms. Below is a list of common terms: |
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|
|
 |
| Annular
Ring: |
| Select
functional portion of conductive material completely surrounding
a hole. |
| Aperture
Information: |
| Common
text file readable by any computer describing the size
and shape of each element on the board. These are also
known as D-code lists.Not necessary if project files are
saved as Extended Gerber with embedded Apertures (RS274X). |
| Array: |
| PCB
elements, groups of elements or circuits arranged in rows
and columns on a base material. |
| Artwork:
|
| Accurately
scaled configuration used to produce the artwork master
or production master. |
| Artwork
Master: |
| Photographic
negative or positive acetate film that embodies the image
of the PCB pattern, commonly on a 1:1 scale. |
| Aspect
Ratio: |
| The
ratio of the PCB thickness to the diameter of the smallest
hole. |
| Automated
Optical Inspection (AOI): |
| Amplified
visual inspection of production circuit boards using a
machine scanner to assess workmanship quality. |
| Automatic
Test Equipment (ATE): |
| Equipment
designed to automatically analyze functional or static
parameters in order to evaluate product performance. |
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| Barrel: |
|
Cylinder formed by plating through a drilled hole. |
| Base
Copper: |
| The
thin copper foil portion of a copper-clad laminate for
PCBs. It can be present on one or both sides of the board,
and on inner layers. |
| Base
Material: |
|
Insulating material upon which a conductive pattern may
be formed. It may be rigid or flexible or both. It may
be a dielectric or insulated metal sheet. |
| Base
Material Thickness: |
|
Thickness of the base material excluding metal foil or
material deposited on the surface. |
| Bed-Of-Nails
Fixture: |
|
Common 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). |
| Bevel: |
|
The angled edge of a printed board. |
| Blind
Via: |
|
Conductive surface hole that connects an outer layer with
an inner layer of a multi-layer board. |
| Blister: |
|
Separation and localized swelling between any of the layers
of a laminated base material, or between base material
or conductive foil. |
| Bond
Strength: |
|
Force per unit space required to separate two adjacent
layers of a board by a force perpendicular to the board
surface. |
| Bow: |
|
Deviation from flatness of a board, characterized by a
roughly cylindrical or spherical curvature such that if
the board is rectangula, its four corners are in the same
plane. |
| B-Stage
Material: |
|
Resin cured sheet material to an intermediate stage (B-stage
resin). The popular term is "Prepreg". |
| B-Stage
Resin: |
|
Thermosetting resin that is in an intermediate state of
cure. |
| Buried
Via: |
|
A via hole that does not extend to the surface of a printed
circuit board. |
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| CAD: |
|
Computer-Aided Design. |
| CAM: |
|
Computer-Aided Manufacturing. |
| Chamfer: |
|
The technique by which a broken corner is created to eliminate
an otherwise sharp edge. |
| Circuit: |
|
Functional interconnection of a number of devices in one
or more closed paths to perform a desired electrical or
electronic response. |
| Circuitry
Layer: |
|
The layer of a printed circuit board containing conductors,
including ground and voltage planes. |
| Clean
room: |
|
Specialized manufacturing room in which the concentration
of airborne particles is controlled to specified limits. |
| Component: |
|
Any electronic device, typically a resistor, capacitor,
inductor, or integrated circuit (IC), that is mounted
to the circuit board and performs a specific electrical
response. |
| Component
Hole: |
|
The hole used for the attachment and electrical connection
of a component termination, such as a pin or wire to the
circuit board. |
| Component
Side: |
|
Top side of the circuit board on which most of the components
will be located. |
| Computer-Aided
Design (CAD): |
|
Common software programs with algorithms for drafting
and modeling, providing a graphical representation of
a printed board’s conductor layout and signal routes. |
| Computer-Aided
Manufacturing (CAM): |
|
The use of computers to analyze and transfer an electronic
design (CAD) to the manufacturing floor. |
| Computer-Integrated
Manufacturing (CIM): |
|
Software that takes assembly data from a CAD or CAM package
and, using a pre-defined factory modeling system, outputs
routing of components to machine programming points and
assembly and inspection documentation. |
| Conductor: |
|
A thin conductive area on a PCB surface or internal layer
usually composed of lands (to which component leads are
connected) and paths (traces). |
| Conductor
Spacing: |
|
The distance between adjacent edges (not centerline to
centerline) of isolated conductive patterns in a conductor
layer. |
| Conductor
Thickness: |
|
The thickness of the conductor including all metallic
coatings. |
| Conformal
Coating: |
|
An insulating protective coating that conforms to the
configuration of the object coated and is applied on the
completed board assembly. |
| Connector
Area: |
|
The portion of the circuit board that is used for providing
electrical connections. |
| Controlled
Impedance: |
|
The matching of substrate material properties with trace
dimensions and locations to create specific electric impedance
as seen by a signal on the trace. |
| Core
Thickness: |
|
The thickness of the laminate base without copper. |
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| Defect: |
|
Any nonconformance to specified requirements by a unit
or product. |
| Definition: |
|
The fidelity of reproduction of pattern edges, especially
in a printed circuit relative to the original master pattern. |
| Delamination: |
|
A separation between any of the layers of the base of
laminate or between the laminate and the metal cladding
originating from or extending to the edges of a hole or
edge of board. |
| Design
Rule Checking: |
|
The use of a computer program to perform continuity verification
of all conductor routing in accordance with appropriate
design rules. |
| Desmear: |
|
The removal of friction-melted resin and drilling debris
from a hole wall. |
| Dewetting: |
|
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. |
| Dielectric: |
|
An insulating medium that occupies the region between
two conductors. |
| Dimensional
Stability: |
|
A measure of the dimensional change of a material that
is caused by factors such as temperature changes, humidity
changes, chemical treatment, and stress exposure. |
| Double-Sided
Board: |
|
A printed board with a conductive pattern on both sides. |
| Drilling: |
|
The act of forming holes (via's) in a substrate by mechanical
or laser means. |
| Dry-Film
Resists: |
|
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. |
| Dry-Film
Soldermask: |
|
Coating material (dry-film resist) applied to the printed
circuit board via a lamination process to protect the
board from solder or plating. |
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| Electroless
Copper: |
|
A thin layer of copper deposited on the plastic or metallic
surface of a PCB from an autocatalytic plating solution
(without the application of electrical current). |
| Electroplating: |
|
The electro deposition of an adherent metal coating on
a conductive object. The object to be plated is placed
in an electrolyte and connected to one terminal of a direct
current (DC) voltage source. The metal to be deposited
is similarly immersed and connected to the other terminal. |
| Epoxy: |
|
A family of thermosetting resins. Epoxies form a chemical
bond to many metal surfaces. |
| Epoxy
Smear: |
|
Epoxy resin that has been deposited on edges of copper
in holes during drilling either as uniform coating or
in scattered patches. It is undesirable because it can
electrically isolate the conductive layers from the plated-through-hole
interconnections. |
| Etchback: |
|
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. |
| Etching: |
|
The chemical, or chemical and electrolytic, removal of
unwanted portions of conductive materials. |
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| Flying
Probe: |
|
A testing device that uses multiple moving pins to make
contact with two spots on the electrical circuit and send
a signal between them, a procedure that determines whether
faults exist. |
| FR-4: |
|
The UL-designated rating for a laminate composed of glass
and epoxy that meets a specific standard for fire-retardance.
FR-4 is the most common dielectric material used in the
construction of PCBs. |
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| Gerber: |
|
A software format used by the photoplotter to describe
the printed circuit board design. |
| Golden
Board: |
|
Known Good Board. |
| Ground
Plane: |
|
A conductor layer, or portion of a conductor layer, used
as a common reference point for circuit returns, shielding,
or heat sinking. |
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| Hole
Breakout: |
|
A condition in which a hole is partially surrounded by
the land. |
| Hole
Pattern: |
|
The arrangement of all holes in a printed board with respect
to a reference point. |
| Hot
Air Solder Leveling (HASL): |
|
A method of coating exposed copper with solder by inserting
a panel into a bath of molten solder then passing the
panel rapidly past jets of hot air. |
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| Imaging: |
|
The process by which panelization data are transferred
to the photoplotter, which in turn uses light to transfer
a negative image circuitry pattern onto the panel. |
| Impedance: |
|
The total passive opposition offered to the flow of electric
current. This term is generally used to describe high-frequency
circuit boards. |
| Inner-layers: |
|
The internal layers of laminate and metal foil within
a multi-layer board. |
| Insulation
Resistance: |
|
The electrical resistance of an insulating material that
is determined under specific conditions between any pair
of contacts, conductors, or grounding devices in various
combinations. |
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| Known
Good Board (KGB): |
|
A board or assembly that is verified to be free of defects.
Also known as a Golden Board. |
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| Laminate: |
|
The plastic material usually reinforced by glass or paper
that supports the copper cladding from which circuit traces
are created. |
| Laminate
Thickness: |
|
Thickness of the metal-clad base material, single- or
double-sided, prior to any subsequent processing. |
| Laminate
Void: |
|
An absence of epoxy resin in any cross-sectional area
that should normally contain epoxy resin. |
| Land: |
|
The portion of the conductive pattern on printed circuits
designated for the mounting or attachment of components.
Also called a pad. |
| Layup: |
|
The process in which treated prepregs and copper foils
are assembled for pressing. |
| Legend: |
|
A format of lettering or symbols on the printed circuit
board: e.g. part number, serial number, component locations,
and patterns. |
| Liquid
Photoimageable Soldermask (LPI): |
|
A mask using photographic imaging techniques to control
deposition. |
| Line: |
|
Conductor. |
| Lot: |
|
A quantity of circuit boards that share a common design. |
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| Major
Defect: |
|
A defect that is likely to result in failure of a unit
or product by materially reducing its usability for its
intended purpose. |
| Mask: |
|
A material applied to enable selective etching, plating,
or the application of solder to a PCB. Also called soldermask
or resist. |
| Metal
Foil: |
|
The plane of conductive material of a printed board from
which circuits are formed. Metal foil is generally copper
and is provided in sheets or rolls. |
| Microsectioning: |
|
The preparation of a specimen of a material, or materials,
that is to be used in metallographic examination. This
usually consists of cutting out a cross-section followed
by encapsulation, polishing, etching, and staining. |
| Minor
Defect: |
|
A defect that is not likely to result in the failure of
a unit or product or that does not reduce the usability
for its intended purpose. |
| Multi-Layer
Board: |
|
Printed boards consisting of a number (four or more) of
separate conducting circuit planes separated by insulating
materials and bonded together into relatively thin homogeneous
constructions with internal and external connections to
each level of the circuitry as needed. |
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| Nomenclature: |
|
Identification symbols applied to the board by means of
screen printing, inkjetting, or laser processes. See Legend. |
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| Outer-layer: |
|
The top and bottom sides of any type of circuit board. |
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| Pad: |
|
Land. |
| Pattern: |
|
The configuration of conductive and nonconductive materials
on a panel or printed board. Also, the circuit configuration
on related tools, drawing, and masters. |
| Pattern
Plating: |
|
The selective plating of a conductive pattern. |
| Photographic
Image: |
|
An image in a photo mask or in an emulsion that is on
a film or plate. |
| Photoplotting: |
|
A photographic process whereby an image is generated by
a controlled light beam that directly exposes a light-sensitive
material. |
| Photo
Print: |
|
The process of forming a circuit pattern image by hardening
a photosensitive polymeric material by passing light through
a photographic film. |
| Phototool: |
|
A transparent film that contains the circuit pattern,
which is represented by a series of lines of dots at a
high resolution. |
| Plated
Through-Hole: |
|
A hole with plating on its walls that makes an electrical
connection between conductive layers, external layers,
or both of a printed board. |
| Platen: |
|
A flat plate of metal within the lamination press in between
which stacks are placed during pressing. |
| Plating
Void: |
|
The area of absence of a specific metal from a specific
cross-sectional area. |
| Plotting: |
|
The mechanical converting of X-Y positional information
into a visual pattern such as artwork. |
| Prepreg: |
|
Sheet material (e.g. glass fabric) impregnated with a
resin cured to an intermediate stage (B-stage resin). |
| Pressing: |
|
The process by which a combination of heat and pressure
are applied to a book, thereby producing fully cured laminated
sheets. |
| Printed
Board: |
|
The general term for completely processed printed circuit
or printed wiring configurations. It includes single,
double-sided, and multi-layer boards, both rigid and flexible. |
| Printed
Circuit: |
|
A conductive pattern that comprises printed components,
printed wiring, or a combination thereof, all formed in
a predetermined design and intended to be attached to
a common base. (In addition, this is a generic term used
to describe a printed board produced by any of a number
of techniques.) |
| Printed
Wiring Board: |
|
A part manufactured from rigid base material upon which
completely processed printed wiring has been formed. |
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| Registration: |
|
The degree of conformity to the position of a pattern,
or a portion thereof, a hole or other feature to its intended
position on a product. |
| Resin
(Epoxy) Smear: |
|
Resin transferred from the base material onto the surface
of the conductive pattern in the wall of a drilled hole. |
| Resist: |
|
Coating material used to mask or to protect selected areas
of a pattern from the action of an etchant, solder, or
plating. Also called soldermask or mask. |
| Rigid-flex: |
|
A PCB construction combining flexible circuits and rigid
multi-layers usually to provide a built-in connection
or to make a three-dimension form that includes components. |
| Router: |
|
A machine that cuts away portions of the laminate to form
the desired shape and size of the printed circuit board. |
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| Scoring: |
|
A technique in which grooves are machined on opposite
sides of a panel to a depth that permits individual boards
to be separated from the panel after component assembly. |
| Screen
Printing: |
|
A process for transferring an image to a surface by forcing
suitable media through a stencil screen with a squeegee. |
| Single-Sided
Board: |
|
A printed board with conductive pattern on one side only. |
| Soldermask
Over Bare Copper (SMOBC): |
|
A method of fabricating a printed circuit board that results
in final metallization being copper with no protective
metal. The non-coated areas are coated by solder resist,
exposing only the component terminal areas. This eliminates
tin lead under the pads. |
| Surface
Mount Technology (SMT): |
|
Defines the entire body of processes and components that
create printed circuit board assemblies with leadless
components. |
| Solder: |
|
An alloy that melts at relatively low temperatures and
is used to join or seal metals with higher melting points.
A metal alloy with a melting temperature below 427°C (800°F). |
| Soldermask: |
|
Coating material used to mask or to protect selected areas
of a pattern from the action of an etchant, solder, or
plating. Also called resist or mask. |
| Step-and-Repeat: |
|
A method by which successive exposures to a single image
are made to produce a multiple image production master. |
| Stripping: |
|
The process by which imaging material (resist) is chemically
removed from a panel during fabrication. |
| Substrate: |
|
A material on whose surface adhesive substance is spread
for bonding or coating. Also, any material that provides
a supporting surface for other materials used to support
printed circuit patterns. |
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| Test
Coupon: |
|
A portion of a printed board or of a panel containing
printed coupons used to determine the acceptability of
such a board. |
| TG: |
|
Glass transition temperature. The point at which rising
temperatures cause the solid base laminate to start to
exhibit soft, plastic-like symptoms. This is expressed
in degrees Celsius (°C). |
| Tooling
Holes: |
|
The general term for holes placed on a PCB or a panel
of PCBs for registration and hold-down purposes during
the manufacturing process. |
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Side: |
|
Component Side. |
| Trace: |
|
A common term for conductor. |
| Traveler: |
|
The list of instructions describing the board, including
any specific processing requirements. Also called a shop
traveler, routing sheet, job order, or production order. |
| Twist: |
|
A laminate defect in which deviation from planarity results
in a twisted arc. |
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| UL: |
|
Underwriters Laboratories, Inc., an independent product
safety testing and certification organization. |
| Underwriters
Symbol: |
|
A logotype denoting that a product has been recognized
(accepted) by Underwriters Laboratories Inc. (UL). |
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| Via: |
|
A plated through-hole that is used as an interlayer connection
but does not have component lead or other reinforcing
material inserted in it. |
| Void: |
|
The absence of any substances in a localized area. |
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| Wave
Soldering: |
|
A process wherein assembled printed boards are brought
in contact with a continuously flowing and circulating
mass of solder, typically in a bath. |
| Working
Master: |
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| X
Axis: |
|
The horizontal or left-to-right direction in a two dimensional
system or coordinates. |
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| Y
Axis: |
|
The vertical or bottom-to-top direction in a two dimensional
system of coordinates. |
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| Z
Axis: |
|
Perpendicular to the plane formed by the X and the Y datum
reference. |
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