Activating | A treatment that renders nonconductive material receptive to
electroless deposition. Also called seeding, catalyzing, and
sensitizing. |
Additive Process | Any process in printed circuit board manufacturing where the
circuit pattern is produced by the addition of metal. |
Analytical Services
Lab | Performs various tests such as plating thickness, inner layer
connections to hole walls, photos or x-rays of circuit boards when
required. |
Annular Ring | The conductive material surrounding a hole. |
Artwork Master | An accurately scaled (usually 1:1) pattern, which is used to
produce the production master. |
Aspect Ratio | The ratio of the circuit board thickness to the smallest
drilled hole diameter. |
B-Stage Material | Sheet material (fiberglass cloth) impregnated with a resin
cured to an intermediate stage (B-stage resin). Pre-preg is the preferred
term. |
Back Planes and
Panels | Interconnection panels onto which printed circuits, other
panels, or integrated circuit packages can be plugged or mounted. Typical
thickness is 0.125"–0.300." |
Barrel | The cylinder formed by plating a drilled hole. |
Base Copper | Copper foil provided in sheet form or clad to one or both sides
of piece of laminate used as either internal or external layers of a circuit
board. |
Base Laminate | The dielectric material upon which the conductive pattern may
be formed. The base material may be rigid or flexible. |
Base Material | See Base Laminate. |
Bed-of-Nails
Technique | A method of testing printed circuit boards that employs a test
figure mounting an array of contact pins configured so as to engage plated
thru-holes on the board. |
Bleeding | A condition in which a plated hole discharges process material
or solution from crevices or voids. |
Blind Via Hole | A plated-through hole connecting an outer layer to one or more
internal conductor layers of a multilayer_ printed board but not extending fully
through all of the layers of base material of the board. |
Blister | 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 delamination. |
Blow Hole | A solder joint void caused by out-gassing of process solutions
during thermal cycling. |
Bond Strength | The force per unit area required to separate two adjacent
layers of a board when applied perpendicular to the board surface. See Peel Strength. |
Breakdown Voltage | The voltage at which an insulator or dielectric ruptures, or at
which ionization and conduction take place in a gas or vapor. |
Bridging, Electrical | The formation of a conductive path between two insulated
conductors such as adjacent traces on a circuit board. |
Buildability Meeting | Team meeting to review customer designs against manufacturing
process capabilities. Used to identify possible failure modes prior to
fabrication. |
C-Stage | The condition of a resin polymer when it is in the fully cured,
cross-linked solid state, with high molecular weight. |
Center-to-Center
Spacing | The nominal distance between the centers of adjacent features
or traces on any layer of a printed circuit board. Also known as
"pitch." |
Chamfer | A corner that has been rounded to eliminate an otherwise sharp
edge. |
Characteristic
Impedance | A compound measurement of the resistance, inductance,
conductance and capacitance of a transmission line expressed in ohms. In printed
wiring its value depends on the width and thickness of the conductor, the
distance from the conductor to ground plane(s), and the dielectric constant of
the insulating media. |
Chase | The aluminum frame used in screening inks onto the board
surface. |
Circuitry Layer | The layer of a PCB containing conductors, including ground and
voltage planes. |
Clad or Cladding | A thin layer or sheet of copper foil, which is bonded to a
laminate core to form the base material for printed circuits. See Base Copper. |
Clearance Hole | A hole in the conductive pattern larger than, but concentric
with, a hole in the printed board base material. |
Coefficient of Expansion,
Thermal | The fractional change in dimension of a material for a unit
change in temperature. |
Component Hole | A hole used for the attachment and electrical connection of
component terminations, including pins and wires, to the printed circuit
board. |
Component Side | That side of the printed circuit board on which most of the
components will be mounted. |
Conductive Pattern | The configuration or design of the conductive material on the
base laminate through which electrical energy passes. Includes conductors,
lands, and through connections. |
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 Base Width | The conductor width at the plane of the surface of the base
material. See Conductor Width. |
Conductor-to-Hole
Spacing | The distance between the edge of a conductor and the edge of
hole. |
Conductor Thickness | The thickness of the trace or land including all metallic
coatings. |
Conductor Width | The observable width of the pertinent conductor at any point
chosen at random on the printed circuit board. |
Contaminant | An impurity or foreign substance whose presence on printed
wiring assemblies could electrically, chemically, or galvanically corrode the
system. |
Continuity | An uninterrupted flow of electrical current in a
circuit. |
Coordinate
Tolerancing | A method of tolerancing hole locations in which the tolerance
is applied directly to linear and angular dimensions, usually forming a
rectangular area of allowable variation. Also see
Positional Limitation Tolerancing and True
Position Tolerance. |
Copper Foil | See Base Copper and Clad or Cladding. |
Core Group | Daily operational meeting held on each shift to communicate
current status of plant in terms of producing and delivering high quality,
cost-effective circuit boards to customers on time. The group identifies
problems that may prevent reaching daily/weekly goals and plans resolution of
those problems. |
Cosmetic Defect | A defect such as a slight change in its usual color that
doesn't affect a board's functionality. |
Cover Lay, Cover Layer, Cover
Coat | Outer layer(s) of insulating material applied over the
conductive pattern on the surface of a printed circuit board. |
Crazing | 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 fibers in the glass cloth and resin
material. |
Current Carrying
Capacity | 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. |
Datum Reference | A defined point, line, or plane used to locate the pattern or
layer for manufacturing, inspection, or for both purposes. |
Deburring | Process of removing traces of base copper material that remain
around holes after board drilling. |
Defect | Any deviation from the normally accepted characteristics of a
product or component. Also see Major Defect and
Minor Defect. |
Definition | The accuracy of pattern edges in a printed circuit relative to
the master pattern. |
Delamination | A separation between any of the layers of a base material or
between the laminate and the conductive foil, or both. |
Desmear | Removal of epoxy smear (melted resin) and drilling debris from
a hole wall. |
Develop | An imaging operation in which unpolymerized (unexposed)
photo-resist is dissolved or washed away to produce a copper board with a
photo-resist pattern for etching or plating. |
Dewetting | A condition that occurs when molten solder has coated a surface
and then recedes, leaving irregularly shaped globules of solder separated by
areas covered with a thin solder film; base metal is not exposed. |
Dielectric | An insulating medium, which occupies the region between two or
more conductors. |
Dielectric Constant | The ratio of permittivity of the material to that of a vacuum
(referred to as relative permittivity). |
Digitizing | Any method of converting feature locations on a flat plane to
digital representation in x-y coordinates. |
Dimensional Stability | A measure of dimensional change caused by factors such as
temperature, humidity, chemical treatment, age or stress; usually expressed as
units/unit. |
Dimensioned Hole | A hole in a printed circuit board where the means of
determining location is x-y coordinate values not
necessarily coinciding with the stated grid. |
Double-Sided Board | A circuit board with conductive patterns on both
sides. |
Drills, Circuit Board | Solid carbide cutting tools with four facet points and two
helical flutes designed specifically for the fast removal of chips in extremely
abrasive materials. |
Dry Film Resists | Coating material in the form of laminated photosensitive sheets
specifically designed for use in the manufacture of printed circuit boards and
chemically machined parts. They are resistant to various electroplating and
etching processes. |
Edge Bevel | A bevel operation performed on edge connectors to improve their
wear and ease of installation. |
Edge-Board Connector | A connector designed specifically for making removable and
reliable interconnection between the edge board contacts on the edge of a
printed board and external wiring. |
Edge Dip Solderability
Test | A solderability test performed by taking a specially prepared
specimen, fluxing it with a nonactivate_d rosin flux, and then immersing it into
a pot of molten solder at a predetermined rate of immersion for a predetermined
dwell time, and then withdrawing it at a predetermined rate. |
Electroless Plating/Electroless
Deposition | The disposition of metal from an auto catalytic plating
solution without application of electrical current. Short for "electrodeless."
This process is required to plate the nonconductive hole walls in order that
they may be subsequently electroplated. Also called "PTH." |
Electroplating | (1) The electrodeposition of a
metal coating on a conductive object. The object to be plated is placed in an
electrolyte and connected to one terminal of a DC voltage source. The metal to
be deposited is similarly immersed and connected to the other terminal. Ions of
the metal provide transfer to metal as they make up the current flow between the
electrodes. (2) The electrolytic process used to deposit a metal on a desired
object by placing the object at one electrical polarity and passing a current
through a chemical solution to another electrode. The metal is plated from
either the solution or the other electrode. |
Entrapment | The damaging admission and trapping of air, flux, and/or fumes;
it is caused by contamination and plating. |
Epoxy Smear | Epoxy resin that has been deposited onto the surface or edges
of the conductive inner layer pattern during drilling. Also called Resin
Smear. |
Etch | Chemical removal of metal (copper) to achieve a desired circuit
pattern. |
Etch Factor | The ratio of the depth of etch (conductor thickness) to the
amount of lateral etch (undercut). |
Etchback | The controlled removal of all components of base material
(glass and resin) by a chemical process on the sidewall of holes in order to
expose additional internal conductor areas. |
Fiducial | Etched features or drilled hole used for optical alignment
during assembly operations. |
Film Artwork | A positive or negative piece of film containing a circuit,
solder mask, or nomenclature pattern. |
First Article | A sample part or assembly manufactured prior to the start of
production for the purpose of assuring that the manufacturer is capable of
manufacturing a product that will meet specified requirements. |
Fixture | A device that enables interfacing a printed circuit board with
a spring-contact probe test pattern. |
Flat | A standard size sheet of laminate material, which is processed
into one or more circuit boards. |
Flux | A substance used to promote or facilitate fusion such as a
material used to remove oxides from surfaces to be joined by soldering or
welding. |
Fused Coating | A metallic coating (usually tin or solder alloy) that has been
melted and solidified, forming a metallurgical bond to the base
material. |
Glass Transition
Temperature | The temperature at which an amorphous polymer (or the amorphous
regions in a partially crystalline polymer) changes from a hard and relatively
brittle condition to a viscous or rubbery condition. When this transition
occurs, many physical properties undergo significant changes. Some of those
properties are hardness, brittleness, coefficient of thermal expansion, and
specific heat. |
Grid | An orthogonal network of two sets of parallel, equidistant
lines used for locating points on a printed circuit 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. |
Haloing | Mechanically induced fracturing delamination on or below the
surface of the base material; it is usually exhibited by a light area around
holes, or other machines areas, or both. |
Hole Breakout | A condition in which a hole is not completely surrounded by the
land. |
Hole Density | The quantity of holes in a printed circuit board per unit
area. |
Hole Void | A void in the metallic deposit of a plated-through hole
exposing the base material. |
Image | That portion on artwork masters, working tools, silk screens,
or photo masks that would be considered the photographic image. Also would
include images created with photo-resists or silk-screening techniques.
Generally, "one image" refers to a single circuit board image; thus there may be
several images per flat. |
Ink | Common term for screen resist. |
Inner layer | Any layer that will be pressed on the inside of a multilayer_
board. |
Inspection Overlay | A positive or negative transparency made from the production
master and used as an inspection aid. |
Insulation Resistance | The electrical resistance of the insulating material
(determined under specified conditions) as measured between any pair of contacts
or conductors. |
Jumper Wire | An electrical connection formed by wire between two points on a
printed board added after the intended conductive pattern is
formed. |
Kerf | A widening of the rout path as may be called out on the
blueprint. Allows extra space for hardware to be attached to the
board. |
Keying Slot | A slot in a printed circuit board that polarizes it, thereby
permitting it to be plugged into its mating receptacle with pins properly
aligned, but preventing it from being reversed or plugged into any other
receptacle. |
Laminate | A product made by bonding together two or more layers of
material. |
Laminate Thickness | Thickness of the base material, not including metal-clad, prior
to any processing. Applies to single- or double-sided material. |
Laminate Void | Absence of laminate material in an area that normally contains
laminate material. |
Laminating Presses,
Multilayer_ | Equipment that applies both pressure and heat to laminate and
pre-preg to make multilayer_ boards. |
Lamination | The process of preparing a laminate. |
Land | A portion of a conductive pattern usually, but not exclusively,
used for the connection and/or attachment of components. Also called
Pad. |
Landless Hole | A plated-through hole without land(s). Also referred to as
padless plated holes. |
Layer-to-Layer
Spacing | The thickness of dielectric material between adjacent layers or
conductive circuitry in a multilayer_ printed circuit board. |
Lay-Up | (1) The technique of registering and stacking layers of
materials (laminate and pre-preg) for a multilayer_ board in preparation for the
laminating cycle. (2) The laying out of repeat images on film to create multiple
groups of circuit boards. (3) The laying out of multiple layers in preparation
for multilayer_ lamination. |
Major Defect | A defect that could result in a failure or significantly
reduces the usability of the part for its intended purpose. |
Mask | A material applied to enable selective etching, plating, or the
application of solder to a printed circuit board. |
Measling | Condition existing in the base laminate in the form of discrete
white spots or "crosses" below the surface of the base laminate, reflecting a
separation of fibers in the glass cloth at the weave intersection. |
Metlab | Short for Metallurgical Laboratory. (1) Refers to the
process(es) of inspecting internal board quality characteristics through the use
of microsections. (2) Used interchangeably with microsection. |
Microsectioning | The preparation of a specimen for the microscopic examination
of the material to be examined, usually by cutting out a cross section, followed
by encapsulation, polishing, etching, staining, and so on. |
Microvia | A via used to make connection between two adjacent layers,
typically less than 6 mils in diameter. May be formed by laser ablation, plasma
etching, or photo processing. |
Mil | One-thousandth of an inch (0.001"). |
Minimum Annular Ring | The minimum metal width, at the narrowest point, between the
circumference of the hole and the outer circumference of the land. This
measurement is made to the drilled hole on internal layers of multilayer_ printed
circuit boards and to the edge of the plating on outside layers of multilayer_
boards and double-sided boards. |
Minimum Electrical
Spacing | The minimum allowable distance between adjacent conductors that
is sufficient to prevent dielectric breakdown, corona, or both, between the
semiconductors at any given voltage and altitude. |
Minor Defect | A defect that is not likely to reduce the usability of the unit
for its intended purpose. It may be a departure from established standards
having no significant bearing on the effective use or operation of the
unit. |
Misregistration | The lack of dimensional conformity between successively
produced features or patterns. |
Multilayer_ Circuit
Board | The general term for completely processed printed circuit
configurations consisting of alternate layers of conductive patterns and
insulating materials bonded together in more than two layers. |
Nail Heading | The flared condition of copper on the inner conductor layers of
a multilayer_ board caused by hole drilling. |
Negative | An artwork master or production master in which the intended
conductive pattern is transparent to light, and the areas to be free from
conductive material are opaque. |
Nonfunctional Land | A land on internal or external layers, not connected to the
conductive pattern on its layer. |
October Project | Industry consortium dedicated to waste reduction in circuit
board manufacturing. |
Outer Layer | A conductive layer that lies on the outside of a
flat. |
Outgassing | Deaeration or other gaseous emission from a printed circuit
board when exposed to the soldering operation. |
Overhang | Increase in printed circuit conductor width caused by plating
build-up or by undercutting during etching. |
Oxide | A chemical treatment to inner layers prior to lamination, for
the purpose of increasing the roughness of clad copper to improve laminate bond
strength. |
Pad | The portion of the conductive pattern on printed circuits
designated for the mounting or attachment of components. Also called
Land. |
Panel | The square or rectangular base material containing one or more
circuit patterns that passes successively through the production sequence and
from which printed circuit boards are extracted. See
Back Planes and Panels. |
Panel Plating | The electrolytic plating of the entire surface of a panel
(including holes). |
Part | Individual items that are not normally subject to disassembly
without destruction. |
Pattern | The configuration of conductive and nonconductive materials on
a panel or printed board. Also the circuit configuration on related tools,
drawings, and masters. |
Pattern Plating | Selective electrolytic plating of a conductive
pattern. |
Peel Strength | The force required to peel the conductor or foil from the base
material. |
Permittivity | Measure of the ability of a material to store electrical energy
when exposed to an electrical field. |
Photomask | A silver halide or diazo image on a transparent substrate that
is used to either block or pass light. |
Photo-resist | A light-sensitive material that is used to establish an image
by exposure to light and chemical development. |
Photo plotter | A high-accuracy (>0.002 inch) flatbed plotter with a
programmable, photo image projector assembly. It is most often used to produce
actual-size master patterns for printed circuit artwork directly on
dimensionally stable, high-contrast photographic film. |
Pilot Order | First production order going through process. |
Pinhole | A minute hole through a layer or pattern. |
Pitch | The nominal distance between the centers of adjacent features
or traces on any layer of a printed circuit board. Also known as
"center-to-center spacing." |
Plated-Through Hole (PTH) | A hole in a circuit board that that been plated with metal
(usually copper) on its sides to provide electrical connections between
conductive patterns layers of a printed circuit board. |
Plating | Chemical or electromechanical deposition of metal on a
pattern. |
Plating Resists | Material that, when deposited on conductive areas, prevents the
plating of the covered areas. Resists are available both as screened-on
materials and as dry-film photopolymer resists. |
Plating Void | The absence of a plating metal from a specified plating
area. |
Plotting | The mechanical converting of x-y positional information into a visual pattern, such as artwork. |
Polymide Resins | High-temperature thermoplastics used with glass to produce
printed circuit laminates for multilayer_ and other circuit applications
requiring high-temperature performance. |
Polymerize | To unite chemically two or more monomers or polymers to form a
molecule with a higher molecular weight. |
Positional Limitation
Tolerancing | Defines a zone within which the axis or center plane of a
feature is permitted to vary from true (theoretically exact)
position. |
Pre-clean | Cleaning steps taken prior to an operation to ensure success of
the operation. |
Pre-preg | Sheet material consisting of the base material impregnated with
a synthetic resin, such as epoxy or Polymide, partially cured to the B-stage (an
intermediate stage). Short for pre-impregnated. See also
B-stage. |
Press-Fit Contact | An electrical contact that can be pressed into a hole in an
insulator, printed board (with or without plated-through holes), or a metal
plate. |
Printed Circuit | A conductive pattern of printed components and circuits
attached to a common base. |
Printed Circuit Board (PCB) | The general term for a printed or etched circuit board. It
includes single, double, or multiple layer boards, both rigid and
flexible. |
Printed Wiring Board | A part manufactured from rigid base material upon which
completely processed printed wiring has been formed. |
Production Master | A 1 : 1 scale pattern that is used to produce one or more
printed boards (rigid or flexible) within the accuracy specified on the master
drawing. (1) Single-Image Product Master: A production master used in the
process of making a single printed circuit board. (2) Multiple-Image Production
Master: A production master used in the process of making two or more printed
circuit boards simultaneously. |
Reflowing | The melting of an electrodeposit followed by solidification.
The surface has the appearance and physical characteristics of being
hot-dipped. |
Registration | The degree of conformity of the position of a pattern, or a
portion thereof, with its intended position or with that of any other conductor
layer of a board. |
Residue | An undesirable substance remaining on a substrate after a
process step. |
Resin Smear | Resin transferred from the base material onto the surface or
edge of the conductive pattern normally caused by drilling. Sometimes called
epoxy smear. |
Resin-Starved Area | A region in a printed circuit board that has an insufficient
amount of resin to wet out the reinforcement completely evidenced by low gloss,
dry spots, or exposed fibers. |
Resist | Coating material used to mask or to protect selected areas of a
pattern from the action of an etchant, solder, or plating. Also see Dry-Film Resists, Plating Resists, and Solder Resists. |
Resistivity | The ability of a material to resist the passage of electrical
current through it. |
Reverse Image | The resist pattern on a printed circuit board enabling the
exposure of conductive areas for subsequent plating. |
Rework | Reprocessing that makes articles conform to
specifications. |
Robber | An exposed area generally attached to a rack used in
electroplating, usually to provide a more uniform current density on plated
parts. Thieves are intended to absorb the unevenly distributed current on parts,
thereby assuring that the parts will receive a uniform electroplated
coating. |
Schematic Diagram | A drawing that shows, by means of graphic symbols, the
electrical connections, components, and functions of an electronic
circuit. |
Screen | A cloth material (usually polyester or stainless steel for
circuit boards) coated with a pattern that determines the flow and location of
coatings forced through its openings. |
Screen Printing | A process for transferring an image to a surface by forcing
suitable media through a stencil screen with a squeegee. Also called silk
screening. |
Selective Plate | A process for plating unique features with a different metal
than the remaining features will have. Created by imaging, exposing, and plating
selected area and then repeating the process for the remainder of the
board. |
Shadowing | A condition occurring during etchback in which the dielectric
material, in contact with the foil, is incompletely removed although acceptable
etchback may have been achieved elsewhere. |
Silk Screening | See Screen
Printing. |
Single-Sided Board | Circuit board with conductors on only one side and no
plated-through holes. |
Solder Leveling | The process of dipping printed circuit boards into hot solder
and leveling with hot air. |
Solder Mask | A coating applied to a circuit board to prevent solder from
flowing onto any areas where it's not desired or from bridging across closely
spaced conductors. |
Solder Masking
Coating | Nonpreferred term for resist. |
Solder Resists | Coatings that mask and insulate portions of a circuit pattern
where solder is not desired. |
Solderability Testing | The evaluation of a metal to determine its ability to be wetted
by solder. |
Squeegee | The tool used in silk screening that forces the resist or ink
through the mesh. |
Starvation, Resin | A deficiency of resin in base material that is apparent after
lamination by the presence of weave texture, low gloss, or dry
spots. |
Step-and-Repeat | A method by which successive exposures of a single image are
made to produce a multiple-image production master. |
Strip | The chemical removal of developed photoresist or plated
metal. |
Substrate | See Base Material. |
Subtractive Process | A process in printed circuit manufacturing where the product is
built by the subtraction of an already existing metallic coating. The opposite
of additive processing. |
Test Coupon | A sample or test pattern normally made outside the actual board
pattern that is used for testing to verify certain quality parameters without
destroying the actual board. |
Thief | See Robber. |
Tooling Holes | Two specified holes on a printed circuit board used to position
the board in order to mount components accurately. |
Traveler | A "recipe" for the manufacture of a board. It "travels" with
each order from start to finish. The traveler identifies each order and gives
instructions for each step in the process. It also provides information for
traceability and history. |
Two-Sided Board | See Double-Sided
Board. |
Underwriters
Laboratory | Certifying agency for consumer electronics. See also Underwriters Symbol. |
Underwriters Symbol | A logotype denoting that the product has been recognized by
Underwriters Laboratory, Inc. (UL). |
Via | A plated thru-hole that is used as an inner-layer connection
but doesn't have component lead or other reinforcing material in
it. |
Void | The absence of substances in a localized area (e.g., air
bubbles). |
Wave Soldering | A process wherein assembled printed boards are brought in
contact with a continuously flowing and circulating mass of
solder. |
Zero Defects Sampling | A statistical based attribute sampling plan (C = O) where a
given sample of parts is inspected and any defects found are cause for rejection
of the entire lot. |
