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A
"A" Wave. Wave, "A"
Å. Angstrom
A/D Converter. Analog-To-Digital Converter
Absorption. The retention of moisture by a substance.
Accelerated Stress Test. A test to deliberately produce a failure.
Acceptable Quality Level (AQL). Maximum number of defects per 100
pieces that are allowable.
Acceptance Tests. Tests deemed necessary to determine the
acceptability of products.
Accuracy. (1) The ability to hit the target. (2) Conformity of a
measured value to the actual value of the sample.
Acoustic Microscopy. A nondestructive test that produces high
resolution ultrasonic images, often used for inspecting component lid
seals and die attach within components.
Acrylic. A monomeric acrylate or methacrylate (acrylic acid or a
derivative thereof) cured in a polymerization reaction brought on by
ultraviolet energy, heat, or a combination of the two.
Acrylic Resin. A thermosetting, transparent, flame resistant resin.
ACS. American Chemical Society
Activated Carbon. A water treatment medium, commonly used for
de-chlorination and for reducing organic chemicals and radon from water.
Activated Carbon is produced by heating carbonaceous substances
(bituminous coal or cellulose-based substances such as wood or coconut
shell) to 700°C or less in the absence of air to form a carbonized char,
and then activating (oxidizing) at 800 to 1000°C with oxidizing gases
such as steam and carbon dioxide to form pores, increasing the surface
area of this adsorbent material. It can be in block, granulated, or
powdered form.
Activated Rosin Flux. Flux, Rosin Activated
Activator. Thermally reactive compounds (such as amine
hydrochlorides or various halides) that break down at elevated
temperatures and enhance the ability of a flux to remove oxides and
other contaminants from surfaces being joined.
Active Components. Electronic components such as semiconductors,
transistors, diodes, etc., that can change the characteristics applied
electrical signal.
Active Hold-Down. The process of pressing a component lead directly
in contact with a bonding pad during soldering to ensure intimate
contact between the lead and pad.
Activity. (1) Activities may consist of moving or handling materials
and components, changing machine or tool settings, turning equipment on
or off, etc. Poorly control of activities can create process variability
and varying quality. (2) Flux Activity
ADC. Analog-To-Digital Converter
Additive Plating. Plating, Additive
Adhesion. The state in which two surfaces are held together by
interfacial forces which may consist of valence forces or interlocking
action.
Adhesion, Mechanical. Adhesion between surfaces in which the
adhesive holds the parts together by interlocking action.
Adhesive. A substance capable of holding material together by
surface attachment.
Adhesive, Anisotropic. An adhesive with a low concentration of metal
particles to permit conduction in the z-axis only.
Adhesive, Conductive. A two part system comprised of a polymer base
and a conductive filler.
Adhesive Failure. Failure resulting from insufficient bond between
the adhesive and one or both substrates. Adhesive strips away from
substrates.
Adhesive Specific. Adhesion between surfaces which are held together
by valence forces or molecular bonding.
Adhesive Tensile Loading. When the acting forces are applied at
right angles to the plane of the adhesive. The tensile strength of a
bond is the maximum tensile load per unit area, required to break the
bond expressed in pounds per square inch.
Adhesive, Thermoplastic melt on application. The process is
reversible.
Adhesive, Thermoset undergo a chemical change during heating. The
change is not reversible. Epoxies and acrylics are thermosets.
AFM. See atomic force microscope.
Ag. Chemical symbol for the element silver.
Aging. The change in the properties of a material over time and
under varying conditions of humidity, temperature, pressure, etc.
Air Knife. (1) A mechanical air pressure amplifier. (2) A plenum
with a narrow opening used develop high velocity air from a low pressure
air source to (a) dry / remove liquid films from surfaces (b) control
the coating of surfaces, or (c) heat or cool.
Algorithm. A set of rules specifying a sequence of actions taken to
solve a problem.
Alignment Hole. Tooling Hole
Alloy. A substance made by melting two or materials together.
Alumina. A common substrate material composed of approximately 95%
Al2O3.
Ambient Level. The values of signals and noise that exist at a test
location when the device under test is not active.
Amorphous Phase. Non-crystalline. Most plastics are amorphous at
processing temperature. Many retain this strength under normal
temperatures.
Analog Circuit. An electrical circuit that provides a continuous
relationship between its input and output.
Analog-To-Digital Converter (ADC or A/D converter). An electronic
circuit that produces a digital output directly proportional to an
analog signal input.
Anechoic Chamber. An enclosure especially designed with walls that
absorb sound or radiation, creating an essentially free-field
environment for testing.
Angle Of Attack. The angle between the squeegee and the stencil or
screen.
Angstrom. A unit of length equal to one hundred-millionth (10^-8) of
a centimeter, often used to specify radiation wavelengths.
Anion. An ion with a negative charge. An anion [such as chloride
(Cl-), nitrate (NO3-), bicarbonate (HCO3-), or sulfate (SO4--)] may
result from the dissociation of a salt, acid, or alkali.
Anion Exchange. Ion Exchange. A water conditioning process.
Antioxidants. Compounds that retard the rate of oxidation of a
polymer.
Anisotropic. Exhibiting different physical properties in different
directions.
Anisotropic Adhesive. Adhesive, Anisotropic
Annular Ring. The pad area that remains after a hole is drilled
through the pad.
ANSI. American National Standards Institute
Antistatic Materials resist turbocharging more than ?00 volts.
Anti-Pad. The area of copper etched away around a via or a plated
through-hole on a power or ground plane, thereby preventing an
electrical connection being made to that plane.
AOI. Automated Optical Inspection
Application-Specific Integrated Circuit (ASIC). An IC device whose
function is designed for a specific application(s).
Aperture. An opening in a stencil or screen.
Aperture, Chemical Etched. An opening in metal stencil created by
coating the metal foil with photoresist, exposing an image both sides
the resist using a phototool, and etching the foil from both sides.
Aperture, Electroformed. An opening in stencil formed by imaging a
photoresist on a substrate and then plating the nickel foil around the
resist to the desired thickness.
Aperture, Electropolished. An electrolytic post-process that
"smooths" the walls of aperture walls to improve solder paste printing.
Aperture Files. Precise x-y location and shape of all apertures
required on a printed circuit board.
Aperture, Laser Cut. An opening in a metal stencil created by using
Gerberâ and aperture
data to position a laser cutting head.
Aperture, Trapezoidal. An aperture with the board side opening 1 to
2 mils larger than the squeegee side opening.
API. Application Program Interface
Application Program Interface. The interface between the
application's software and the application platform.
Application Software. A program that performs a specific service or
solves a particular problem.
AQL. Acceptable Quality Level
Aqueous. A water soluble.
Aqueous Cleaning. Cleaning, Aqueous
Architecture. A structured set of protocols that implement the
functions of the system.
Array. A group of components arranged on rows and columns.
Artwork. A phototool used to create (1) features during printed
circuit board fabrication or (2) apertures on a screen or a chem-etched
stencil.
Artwork Generation. The process of transferring the CAD circuit
layout to reproducible artwork for use by stencil and printed circuit
board fabricators.
Artwork Master. Artwork used to produce production masters.
ASIC. Application Specific Integrated Circuit
ASME. American Society of Mechanical Engineers
Aspect Ratio. (1) Thickness of a printed circuit board to the
diameter of the smallest hole. (2) Thickness of a stencil to the width
of the smallest aperture.
Assembler. A program that translates mnemonics into binary codes
that run on a computer.
Assembly. A functional subdivision of a component, consisting of
parts or subassemblies that perform functions necessary for the
operation of the component as a whole. Examples: regulator assembly,
power amplifier assembly, gyro assembly, etc.
AST. Accelerated Stress Testing
ASTM. American Society for Testing and Materials
Asynchronous. An action that takes place at an arbitrary time,
without synchronization to a reference timer or clock.
ATE. Automatic (Automated) Test Equipment
Atm. Atmosphere pressure
Atomic Force Microscope (AFM). A microscope that works by bringing a
fine needle right up to the surface of a semiconductor and tracing the
topography of the material. AFMs are an alternative to scanning electron
microscopes as a means of measuring and monitoring the widths and
heights of critical dimensions on an integrated circuit die.
Au. Chemical symbol for the element gold.
Automated Optical Inspection (AOI). A mechanized visual inspection
process.
AWG. American Wire Gage
Axial Lead. Lead wire extending from a component or module body
along its long axis.
Axial Leaded Components are usually cylindrical in shape and have
leads exiting from opposite ends along its long axis.
Azeotrope. A liquid mixture with a constant maximum or minimum
boiling point lower or higher than the boiling points of its components
and with the capacity to distill without change in composition.
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B-Stage Resin. An intermediate stage in curing a thermoset resin.
Prepreg
Back End Of The Line (BEOL). Test, assembly, and packaging of wafer
manufacturing.
Ball Bonding. Bonding, Ball
Ball Grid Array (BGA) is surface mount technology IC package that
provides electrical advantage of shorter signal and power paths and the
mechanical advantage of greater interconnects and higher lead pitch,
while decreasing package size.
Bare Board. An unpopulated printed circuit board.
Bare Die. An unpackaged integrated circuit.
Barrel. The cylinder formed in the drilled through hole in a printed
circuit board.
Base Board. Base Material
Base Material. In printed circuit board fabrication, the insulating
laminate where the conductor pattern is formed.
Batch. An entity that represents the production at any point in the
process. A batch is a running control recipe. The material that is being
produced or that has been produced by a single execution of a recipe is
also considered a batch.
Batch Control. Consists of a sequence of one or more steps (phases)
that must be performed in a defined order for a finite period of time to
process finite quantities of input material to produce finished product.
Batch Manufacturing. Manufacturing in groups, lots or batches in
which each part or finished good is identical.
Batch Processing. The method adopted when the required product
volumes do not allow continuous production of one product on particular
machines.
BBA. Bus Ball Array
Bed-Of-Nails. A test fixture, used with (automated) test equipment,
made of spring loaded contact pins (Pogoâ pins) located to correspond with desired
measurement points (nodes) on a printed circuit board.
Bend Radius. The radius at the inside of the bend at (1) the lead
shoulder leading to the leg and (2) the base of the leg leading to the
foot.
BEOL. Back End Of The Line
BGA. Ball Grid Array
Bi. Chemical symbol for the element bismuth.
Bifurcated Terminal. Terminal, Bifurcated
Binder. Materials added to pastes and adhesives to provide strength
for handling purposes.
Binning. Classifying components by their performance at the final
test. The analogy is to physically drop things into different bins.
Bipolar. (1) A signal that includes positive and negative values.
(2) A type of semiconductor.
Birdcage. A defect in stranded wire where the strands in the
stripped portion between the covering of an insulated conductor and a
soldered connection (or an end-tinned lead) have separated from the
normal lay of the strands.
BIST. Built-In Self Test
BIT. Built-In Test
Blind Via. Via, Blind
Blister. Raised areas on the surface of the laminate caused by the
pressure of volatile substances entrapped within the laminate.
Blow Hole. A cavity in the solder surface whose opening has an
irregular and jagged form, without a smooth surface.
Board. Printed Circuit Board
Board-Level (Circuitry) Repair. Repair, Board-Level (Circuitry)
BOD. Biological Oxygen Demand
Bond Strength. The force per unit area required to separate two
adjacent layers of a package. The force is applied perpendicular to the
surface of the package.
Bonding. Joining of two materials.
Bonding Alloy. Solder
Bonding, Ball. A wire bonding method that melts a sphere of gold
wire, melts the sphere at the first connection point, draws a loop in
the wire, and makes a wedge bond at the other connection point.
Bonding, Die. The attachment of an integrated circuit chip to a
substrate.
Bonding Pad. Pad. Termination
Bonding, Tape. Using a metal or plastic tape material to support the
carrier of a component in a gang bonding process.
Bonding, Thermocompression. Machines that use pressure and heat in
the absence of electrical current and without an intermediate material
to form wire bonds.
Bonding, Thermosonic. Machines that use heat (typically 150°C),
ultrasonic energy, force, and time to form wire bonds.
Bonding, Ultrasonic. Machines that use ultrasonic energy, force, and
time to form wire bonds.
Bonding, Wedge. A wire bonding method that can use either gold or
aluminum wire. Aluminum wedge bonds are made with ultrasonic bonding
machines. Gold wedge bonds are made using thermosonic bonding machines.
Bonding, Wire. A die connect methodology that runs either gold or
aluminum wires between pads on the integrated circuit to either a lead
frame or pads on a printed circuit board. Ball and wedge bonding are
primary wire bonding methods, of which ball bonding is more common.
Boundary Scan. A functional test designed into integrated circuits.
Bow. A cupped variation from a known flatness of a printed circuit
board.
Breakaway Tabs. Excess material left on printed circuit boards
during fabrication to improve board handling that is removed after
assembly.
Breakout. Poor registration between the hole and the pad on a
printed circuit board to the degree that the hole is not within the area
of the pad.
Bridging. A buildup of solder between components, conductors, and/or
base substrate forming an undesired conductive path.
British Standards Institute (BSI). A standard setting organization.
BSI. British Standards Institute
Buffer. A solution that minimizes changes in hydrogen ion
concentration that would otherwise occur as a result of a chemical
reaction.
Built-In Self Test (BIST). Test, Built-In
Built-In Test (BIT). Test, Built-In
Bulk Components. Packaging with loose chip or MELF components that
with a special feeder present the parts the pick and place head.
Bump. A small mound formed on the device or the substrate pads that
can be used as a contact for face-down bonding. This is a method of
providing connections to the terminal areas of a device.
Buried Via. Via, Buried
Burn-In. An accelerated stress test run at elevated temperature to
weed-out marginal components.
BPA. Bus Pad Array
Butt Lead Package. I Lead Package.
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C4. Controlled Collapse Chip Connection
C5. Controlled Collapse Chip Carrier Connection
C-Stage Resin. A resin in the final stage of curing.
CAD. Computer Aided Design
CAGR. Compound Annual Growth Rate
CAM. Computer Aided Manufacturing
Camera, Component. An upward looking camera used to determine part
position offsets required for proper placement.
Camera, Fiducial. A downward looking camera in the placement head
used to determine position of the printed circuit board relative to the
head. Or vice versa.
Canadian Standards Association (CSA). A Canadian safety standard
certification organization.
Capability. Process Capability
Capability Ratio. Cp
Capability Ratio, Centered. Cpk
Capacity Buy. Buying of equipment to increase manufacturing
capacity, as opposed to a technology buy.
Capillary Action. A flow of a fluid against gravity between solid
surfaces.
Card. Printed Circuit Board
Carrier Tape. Tape, Carrier
CASE (Tools). Computer-Aided Software Engineering.
Castellation. Metalized features that are recessed on the edges of a
chip carrier, which are used to interconnect conducting surfaces or
planes within a chip carrier or on the chip carrier.
Catalyst. A chemical that changes the rate of a chemical reaction.
Cation. A positively charged ion in an electrolyte solution,
attracted to the cathode under the influence of a difference in
electrical potential. Sodium ion (Na+) is a cation.
Cation Exchange. Ion Exchange. A water conditioning process,
commonly used for water softening.
Cation Exchange Resin. Cation exchanger. Base exchanger. An ion
exchange material possessing reverse exchange ability for cations.
Sulfonated polystyrene copolymer divinylbenzene (DVB) exchange resin is
used almost exclusively today in ion exchange water softeners.
CBGA. Ceramic Ball Grid Array
Chip Carrier
CCGA. Ceramic Column Grid Array
Centered Capability Ratio. Cpk
Centering. Correcting the actual center of a part on a nozzle after
picking to the true center of the nozzle.
Centering, Mechanical. Repositioning a part on a nozzle after it has
been picked using spring-loaded jaws that close around the part and move
it to the proper position.
Centering, Vision. Using a camera to determine position offsets to
compensate for the location of the part on the nozzle.
Ceramic. An inorganic, nonmetallic material, such as alumina,
beryllia, steatite, or forsterite, which is fired at a high temperature.
Ceramics are used in electronics as a substrate or to create component
packages.
Ceramic Ball Grid Array (CBGA). A ball grid array (BGA) package of
cofired alumina ceramic substrate allowing various lid sealing and
encapsulation techniques.
Ceramic Column Grid Array (CCGA). A ceramic ball grid array (CBGA)
with solder columns replacing the solder balls.
Certification. The act of verifying and documenting that personnel
have completed required training and have demonstrated specified
proficiency and have met other specified requirements.
CFC. Chlorinated Fluorocarbon (Chlorofluorocarbon)
CFR. Code of Federal Regulation
CGA. Column Grid Array
Chelating Agent. This agent forms a bond with the ions, such as
calcium and magnesium ions and prevents precipitation of calcium and
magnesium salts as hard water.
Chelation. The mechanism by which chemicals that would otherwise
precipitate are complexed in solution with a chelating agent.
Chemical Etched Aperture. Aperture, Chemical Etched.
Chemical Etched Stencil. Aperture, Chemical Etched.
Chemical Vapor Deposition (CVD). Deposition of thin films (usually
dielectrics/insulators) on silicon wafers by placing the wafers in a
mixture of gases which react at the surface of the wafers.
Chem-Etched. Chemical(ly) Etched.
Chip. (1) Chip Component. (2) Integrated Circuit. (3) Bare die.
Chip Carrier. A low profile four sided (rectangular) part package,
whose semiconductor chip cavity or mounting area is a large fraction of
the chip size.
Chip Component. A SMT passive device, including resistors,
capacitors, and inductors.
Chip On Board (COB). An unpackaged silicon die mounted directly on
the printed circuit board and connected with wire bonds.
Chip Scale Package. A popular description is that a CSP must be no
more than 120% the X and Y dimensions of the silicon die within the
package. So, the CSP is a die on a carrier substrate. In order to
maintain the CSP die to package ratio the CPS is generally a ball grid
array. So, this description becomes fuzzy because CSP fabricators
routinely shrink the die to reduce cost, but generally do not change
packaging.
Chip Shooter. A high speed surface mount component handler and
placer.
Chlorofluorocarbon (CFC). A chemical that was used in the
electronic, chemical, and refrigeration industries.
CIM. Computer Integrated Manufacturing
Circuit. Circuitry
Circuit Width. Conductor Width
Circuitry. The configuration or design of the conductive material on
the base material. This includes conductors, lands, and through
connections when these connections are an integral part of the
manufacturing process.
Circuitry-Level Repair. Repair, Board-Level (Circuitry)
Circumferential Separation. A crack or void in the plating extending
around the entire circumference of a PTH, or in the solder fillet around
the conductor, in the solder fillet around an eyelet, or at the
interface between a solder fillet and a land.
Clamshell (Fixture). A two sided test fixture that opens like a book
(clamshell) to accept the printed circuit board or assembly for testing.
Class XXXX Clean Room. A clean room rating system. For instance, a
Class 100,000 Clean Room limits the particle count to less than 3500
particles per liter (100,000 particles per cubic foot) of a size of 0.5
micron or larger, or 25 particles per liter (700 particles per cubic
foot) of a size 5.0 microns or larger.
CLCC. Ceramic Leaded Chip Carrier
Clean Room. An enclosed room employing control over particulate
matter in the air with temperature, humidity, and pressure controls.
Cleaning. The process of removing flux residues and other
contaminants from the surface of a printed circuit assembly.
Cleaning, Aqueous. Cleaning parts with water (e.g., tap, pure, or
de-ionized) as the primary cleaning fluid.
Cleaning, Manual. Spot cleaning flux residues from assembly
surfaces, usually using a brush and isopropyl alcohol as the cleaning
agent or solvent.
Cleaning, Plasma. A bonding pad preparation process that uses
electrically excited gas molecules to remove surface contamination.
Cleaning, Semiaqueous. A cleaning process using a solvent followed
by a hot water rinse and drying.
Cleaning, Solvent. A cleaning process using chlorinated and
fluorinated hydrocarbon liquids.
Cleaning, Ultrasonic. A cleaning process using ultrasonic energy
(mechanical oscillation ) along with a chemical solvent.
Cleaning, Vapor Degreaser. A cleaning process where a heated solvent
is condensed on the printed circuit board to be cleaned.
Client. A software application which communicates with another
software application (the server). The server normally supplies data or
functions to the client.
Clinched Lead. A pin through hole lead that is bent on the solder
side of the printed circuit board to hold the component in place prior
to soldering.
Contract Manufacturing (Manufacturer)
CMOS. Complementary Metal Oxide Semiconductor
CMS. Contract Manufacturing Services
Coating. A thin layer of conductive or dielectric material applied
over components or a base material.
COB. Chip On Board
Cohesive Failure occurs when internal strength of the adhesive is
not as great as the forces applied to it. Adhesive remains bonded to
both substrates.
Coefficient of Thermal Expansion (CTE). The ratio of change in
dimension per unit change in temperature.
Cofire. A process for forming multilayer ceramic substrates in which
thick-film conductors and dielectrics are simultaneously processed by a
firing cycle.
Cold Flow. Movement of insulation (e.g. Teflon) caused by pressure.
Creep.
Cold-Junction Compensation. An artificial reference level that
compensates for ambient temperature variations in thermocouple circuits.
Cold Solder Joint. Solder Joint, Cold
Colloid. A substance that remains suspended in a solution or fails
to settle out of solution.
Column Grid Array (CGA). A packaging technology similar to a pin
grid array, in which a device's external connections are arranged as an
array of conducting pins on the base of the package. However, in the
case of a column grid array, small columns of solder are attached to the
conducting pads.
Comb Pattern. Two sets of interconnected interspaced finger-like
arrays of uniformly spaced conductors. SIR testing requires comb
patterns on printed circuit boards.
Combinational Testing. Test, Combinational
Compiler. A program that translates high-level-language statements
into codes that a computer can execute.
Component. (1) A functional subdivision of a system, generally a
self-contained combination of assemblies performing a function necessary
for the system's operation. Examples: power supply, transmitter, gyro
package, etc. (2) A part of an assembly or subassembly. A part.
Component Camera. Camera, Component
Component Hole. Plated-Through-Hole (PTH)
Component Lead. A wire or formed conductor extending from a
component and serving as a mechanical and/or electrical connection.
Component-Level Repair. Repair, Component-Level
Component Side. Primary side
Composite. A resin combined with another material, such as glass
fiber, to improve physical properties.
Computer Aided Design (CAM). A design method that uses computer
generated images, rather than mechanical drawings.
Computer-Aided Software Engineering (CASE) Tools allow users to make
changes in the way they access information from a relational data base.
Computer Integrated Manufacturing (CIM). Linking computer aided
design data to the computer controlled assembly and test equipment used
to produce the product.
Conductive Adhesive. Adhesive, Conductive
Conductive Material. Electrostatic Conductive Material
Conduction (Soldering). Soldering, Conduction
Conductor. A lead, solid or stranded, or printed wiring path serving
as an electrical connection.
Conductor Spacing. The distance between traces on a printed circuit
board.
Conductor, Thermal. Thermal Conductor
Conductor Thickness. The thickness of the conductor including all
metallic coatings, excluding non-conductive protective coating.
Conductor Width. The observable width of a circuit or conductor at
any point chosen at random. The width is measured from directly above.
Conformal Coating. A thin electrically nonconductive protective
coating that conforms to the configuration of the covered assembly to
provide environmental and mechanical protection.
Conformity. The ability to satisfy specified requirements.
Connection. An electrical termination that was soldered. A solder
joint.
Connection, Interlayer. An electrical connection between conductive
patterns in different layers of a printed circuit board. Via
Construction Analysis. Destructive Physical Analysis (DPA). The
process of destructively disassembling, testing, and inspecting a device
for the purpose of determining conformance with applicable design,
process, and workmanship requirements.
Contact Angle. Wetting angle. The angle of wetting between a solder
fillet and the pad or component lead. A small contact angle indicates
good wetting, and a large angle indicates poor wetting.
Contact Resistance. The maximum resistance allowed between a pin and
the socket contacts of a connector when assembled and in use.
Contaminant. An impurity or foreign substance present in a material
that affects one or more properties of the material. A contaminant may
be or not be ionic.
Control Chart. A chart for tracking a series of measurements taken
over time.
Control System. A system to guide or manipulate various elements in
order to achieve a prescribed result.
Convection. Transfer of energy (heat) by the circulation of a fluid
or gas.
Conveyor. A machine that supports a printed circuit board and moves
it from one location to another.
COO. Cost Of Ownership
Coplanarity. The vertical spread in the measurement of the lowest
and highest contact ("out-of-line") of a package.
Copper Tin Intermetalic. Intermetalic, Tin Copper
Core Material. In printed circuit board fabrication, fully cured
inner layers of a multilayer printed circuit board.
Core Solder. Solder, Wire/Core
Corrosion. The chemical reaction of a metal in contact with the air.
COTS. Commercial Off The Shelf
Coupon. A portion of a printed circuit board used for testing.
Court Yard. The keepout area of a surface mount component.
Cover Tape. Tape, Cover
Cp. Capability Ratio. Measurement of the width of the distribution
of process measurements, compared to a desired point.
Cpk. Centered Capability Ratio. Measurement of the mean of process
measurements, compared to a desired point.
Crazing. An internal condition occurring in the laminate base
material in which the glass fibers are separated from the resin, caused
by mechanical stress.
Creep. Cold Flow
Critical Dimension (CD). The minimum width that is allowed as part
of the circuit design, on any given patterning layer.
Critical Path Method. A technique to determine the order in which
operations must be executed to complete a project in minimum time, and
determine which operations have some "float" or capacity to be
rescheduled without affecting the minimum time.
CRT. Cathode Ray Tube
Crystallinity. A state of molecular structure in some polymers
denoting uniformity and compactness of the molecular chains.
CSA. Canadian Standards Association
CSP. Chip Scale Package
CSP-C. Ceramic Chip-Scale Package
CSP-L. Laminate Chip-Scale Package
CTE. Coefficient of Thermal Expansion
CTE Mismatch. The difference in the CTE of two materials or
components joined together. This mismatch can produce strains and
stresses at joining interfaces or in attachment surfaces.
Cu. Chemical symbol for the element copper.
Cup Terminal. Terminal, Cup
Cure. A heat, catalyst, or pressure activated chemical reaction that
changes the physical properties of a material.
Curing Cycle. The time-temperature profile needed to cure a
thermosetting material like a bonding adhesive.
Curing Time. The time needed to cure a thermosetting plastic
material.
Cycle Rate. A dry run time.
CVD. Chemical Vapor Deposition
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DAC or D/A Converter. Digital-To-Analog Converter
DARPA. Defense Advanced Research Projects Agency
Data Acquisition System. Any device that acquires information from
sensors using amplifiers, multiplexers, and analog to digital
converters.
DCA. Direct Chip Attach
DCS. Distributed Control System
DDA. Direct Die Attach
DDE. Dynamic Data Exchange
Defect. Any nonconformance to specified requirements by a unit or
product.
Definition. Degree that a produced pattern matches the master
pattern.
Defluxing. Cleaning. Removing flux residues after a soldering
operation.
Degradation. Destructive change in the chemical structure of a
plastic reflected in its appearance or physical properties.
Degreasing. Cleaning. Removing wave oil and flux residues after a
soldering operation.
Deionized (DI) Water. A pure form of water with no ionized material.
Delamination. A separation of the bonded layers or foils of a
laminated material, such as a printed circuit board.
Dendrite. Metallic filaments growing by electromigration between two
points.
Density. The weight of a material in relationship to its volume.
Deposition. The process of applying a material on a substrate by
applying pressure through a screen or stencil.
Desiccant. A substance, such as calcium oxide or silica gel, with a
high attraction for water and is used as a drying agent.
Desiccant Cabinet. A nitrogen atmosphere storage area for moisture
sensitive parts.
Design Of Experiments (DOE). A statistical technique for determining
the relationship between and relative importance of various factors
controlling a process.
Design Rules. Allowable dimensions, keepout areas, and tolerances
used in the layout and design of circuitry.
Desoldering. A disassembly method of removing the solder from
components on a printed circuit board.
Detergent. A product designed to make materials, often oils and
greases, soluble in water. Usually, detergents are made from synthetic
surfactants.
Deviation. A specific authorization, granted before the fact, to
depart from a particular requirement of specifications or related
documents.
Device. Component
Dewetting. The condition in the solder joint in which the liquid
solder has not adhered intimately with one or more the components.
Characterized by an abrupt boundary between the solder and the component
lead or conductor. Can be distinguished by a "rolling back" of the
solder from the lead or conductor.
DFA. Design For Assembly
DFT. Design For Test
DI (Water). Deionized water.
Diazo. A type of artwork film.
Die. Integrated circuit chip as diced or cut from the finished
wafer.
Die Attach. Bonding a die to its mount in its package. This is often
done with a metal based glue-like silver epoxy for good conduction of
heat away from the chip.
Die Bonding. Bonding, Die
Dielectric. Nonconducting material used to encapsulate circuitry and
in the manufacture of capacitors and printed circuit boards.
Dielectric Constant. That property of a dielectric which determines
the electrostatic energy per unit volume for unit potential grade.
Dielectric Strength. The voltage at which an insulating material can
withstand before breaking down occurs, usually expressed as volts per
mil.
DIP. Dual Inline Package
Diffusion. A material transport phenomena that occurs in solids, and
is caused by the continual physical motion of atoms from one position to
another. This results in the flow of material from regions of high
concentration to regions of low concentration.
Digital. A type of circuit in which the signals can have only one of
two possible states, a "1" or a "0".
Digital-To-Analog Converter (DAC or D/A Converter). A device that
converts digital information into a corresponding analog voltage or
current.
Dikes. Side Cutter
Direct Chip Attach (DCA). Chip-on-board technology.
Direct Die Attach (DDA). Direct Chip Attach
Direct Memory Access (DMA). The direct transfer of information
between a computer's memory and a device while the computer's CPU does
something else.
Discrete Components. Individual resistors, capacitors, diodes etc.
Dispense (ing). A machine or manual method of applying solder paste,
adhesives, and other gels using air or mechanical pressure to force the
material being dispensed through a nozzle or tip onto a substrate.
Dispersants. Organic and inorganic phosphates and polymers used in
aqueous cleaning to assist in the removal of insoluble materials.
Dissipation Factor. The tangent of the loss angle of the insulating
material.
Dissipative Material. Electrostatic Dissipative Material
Dissociation. The separation of an electrolyte into ions of opposite
charge.
Distributed Control System (DCS). A real-time control system for
continuous and batch process applications.
Distributed Processing. The physical and/or logical connectivity of
hardware, software, information and load sharing.
Disturbed Solder Joint. Solder Joint, Disturbed
Divinylbenzene (DVB). A widely used cation exchange resin.
Document Management System. Provides storage, retrieval and
manipulation of documents in a compact space.
DOE. Design Of Experiments
Double-Sided Assembly. A printed circuit assembly with components on
both sides of the substrate.
Double Sided Reflow Soldering. Reflow Soldering, Double Sided
Down Force. Squeegee Pressure.
DMA. Direct Memory Access
DPA. Destructive Physical Analysis or Construction Analysis
DPM. Defects Per Million (opportunities)
DRAM. Dynamic Random Access Memory
Draw Bridge. Tomb Stone
Drill Files. Precise x-y location and sizes of all holes required on
a printed circuit board.
Drill Wander. In printed circuit board fabrication, deviation from
the target drilling location.
Dry Etching. Plasma Etching
Dry Run (ning). Operating a machine without processing. For
instance, dry running a placement machine sequentially moves the head to
the feeders and the component placement locations.
Dross. Chiefly tin oxide, but contains oxidized lead and other
contaminants that form on the surface of molten solder.
Dross Content. A measure of the cleanliness of solder powder.
DSP. Digital Signal Processor
Dual Inline Package (DIP). A PTH package with two parallel rows of
leads extending from the base of the component. Standard lead pitch is
0.100 inch.
Dry Film (Solder Mask). Solder Mask, Dry Film
Dual Gantry. A machine positioning system with two independent
gantries.
Dual Wave Soldering. Soldering, Dual Wave
Dummy Component. A non-functional component package.
Dummy Land. A conductor on a printed circuit board that is not
connected electrically to other circuitry.
Dummy Pad. Pad, Dummy
Durometer. A measure of the hardness of a non-metal.
DVB. Divinylbenzene
Dynamic Data Exchange. DDE is a communication protocol that allows
Windows® programs
to communicate with each other.
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E
Edge Connector. The portion of the PCB used to provide external
electrical connection.
Edge Clearance. A keepout area on the side and each ends of printed
circuit boards required for board handling.
EDS. Energy Dispersive Spectrograph
EIA. Electronic Industries Association
EIAJ. Electronic Industries Association of Japan
Elastomeric. A material that at room temperature can be stretched
repeatedly to at least twice its original length, and upon release of
the stress, will return with force to its approximate original length.
Rubber band material is elastomeric.
Electrochemical Migration. An unplanned electrolytic plating
process. A film of polar solvent, often water, on a substrate surface
provides for current flow between points with a difference in electrical
potential.
Electrode. A conductor through which a current enters or leaves an
electrolytic cell, vacuum tube, or any nonmetallic conductor.
Electroformed Aperture. Aperture, Electroformed
Electroformed Stencil. Stencil, Electroformed
Electroless Nickel - Immersion Gold. A coating applied during
printed circuit board fabrication to protect copper features from
oxidation.
Electroless Plating. Plating, Electroless
Electrolyte. Compounds that conduct an electric current by the
movement of ions.
Electrolytic Corrosion. Corrosion by means of electrochemical
action.
Electrolytic Plating. Plating, Electrolytic
Electromagnetic Compatibility (EMC). (1) The ability of electronic
equipment to operate in an intended electromagnetic environment without
degradation caused by interference. (2) The ability of equipment to
operate in its electromagnetic environment without creating interference
with other equipment.
Electromigration. Electrochemical Migration
Electroplating. Electroless Plating.
Electropolished Aperture. Aperture, Electropolished
Electropolished Stencil. Stencil, Electropolished
Electrostatic Conductive Material. Material with a surface
resistivity of 10 ohms per square maximum.
Electrostatic Discharge (ESD). The transfer of a charge when the two
objects have different electrostatic potentials. The potentials can be
caused by either direct contact or induced by an electrostatic field. In
electronic manufacturing, the employee working on a printed circuit
board and a component on the same board can have different electrostatic
potentials, which will damage electronic components.
Electrostatic Dissipative Material. Materials with a surface
resistivity greater than 10^5, but less than 10^12 ohms per square.
Electrostatic Field. A voltage gradient between an
electro-statically charged surface and another surface of a different
electrostatic potential.
Electrostatic Insulating Material. Materials with a surface
resistivity greater than 10^12 ohms per square.
Elevator, Tray. Feeder, Tray
Elongation. The fractional increase in length of a material stressed
in tension.
Embossed Tape. Tape, Embossed
EMC. Electromagnetic Compatibility
EMI. Electromagnetic Interference
EMS. Electronic Manufacturing Services
Emulsifier. An aqueous additive used to keep soils dispersed
throughout the cleaning fluid.
Emulsion. A material that suppliers build-up on a printing screen to
block portions of the screen. The un-blocked (open) portion of the
screen define the pattern for depositing solder paste on the printed
circuit board.
Encapsulating. Potting. Enclosing an article in an envelope of
adhesive.
Encapsulating Compound. An electrically nonconductive compound used
to completely enclose and fill in voids between electrical components or
parts.
Encoder. A precision glass or metal ruler mounted on the frame of a
machine that is used to measure the location of a moveable head.
Encoders can be either linear or rotary.
ENIG. Electroless Nickel - Immersion Gold
Enterprise Resource Planning (ERP). A logistical extension of MRP.
EPBGA. Enhanced Plastic Ball Grid Array
Epoxy. A polymer thermosetting resin used to bond materials.
Epoxy Resin. A material that forms straight chain thermoplastic and
thermosetting resins. Epoxy resins have excellent mechanical properties
and good dimensional stability.
EPROM. Electronic Programmable Read Only Memory
ERP. Enterprise Resource Planning
ESD. Electrostatic Discharge
ESD Sensitive. Electrical and electronic parts, assemblies and
equipment that could be damaged by ESD voltages.
ESDS. Electrostatic Discharge Sensitive
Etch Factor. The ratio of etch depth to the amount the resist is
undercut during etching.
Etching. The process of selectively removing any material not
protected by a resist using an appropriate solvent or acid.
Ethyline Vinyl Acetate Resins (EVA). Co-polymers of the polyolefins
family derived from random co-polymerization of acetate and ethylene.
Eutectic. An alloy with a lower melting point lower than the melting
points of its components. 63% tin and 37% lead (63Sn/37Pb) solder is
referred to as eutectic solder. Eutectics change directly from liquid to
solid, and the reverse, with no intermediate plastic states.
EVA. Ethyline Vinyl Acetate Resins.
Event Counter. A circuit that counts the occurrences of a certain
condition.
Excessive Solder Joint. Solder Joint, Excessive
Excellon® Files.
Drill files
Excising. Cutting component leads free from the remainder of the
package to prepare the component for forming or placement.
Expert System. Software that applies knowledge and reasoning
techniques that involve rules and heuristics to solve problems normally
requiring the abilities of human experts.
Exudation. Migration of adhesives from the interior to the surface
of plastic.
Eyelet. A hollow tube inserted in a terminal or printed circuit
board to provide mechanical support for component leads or for
electrical connection.
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F
Farad
Fab. Fabrication. A "fab" can refer to either the fabricator or the
printed circuit board made by the fabricator.
Failure. The temporary or permanent functional impairment of a
component or device caused by physical, mechanical, chemical, or
electrical damage.
Failure Mode Effect Analysis (FMEA). A structured evaluation of the
impact of a failure on product or process functionality, safety,
usability, maintainability, availability, and testability.
Fault Tolerance. The ability to execute tasks regardless of the
failure of strategic components.
FBGA. Fine-pitched BGA
FBGA flange package. Fixed body size CSP. A substrate that extends
beyond the boundaries of the die. The package retains its board
footprint, regardless of die size.
FBGA real chip size. CSP in which the package dimension is closely
related to the die size. The package shrinks every time there is a die
shrink.
FBGS. Fine-Pitch Ball Grid Array
FCIP. Flip Chip In Package
FCT. Flip Chip Technology
FEOL. Wafer manufacturing Front-End-Of-The-Line processing.
FESEM. Field Emission Scanning Electron Microscope
FIB. Focused Ion Beam
Field Emission Scanning Electron Microscope (FESEM). A conventional
SEM, except that a cold field emission electron source is used,
providing higher image resolution, increased signal to noise ratio, and
increased depth of field.
File Transfer Protocol (FTP). A protocol that transfers files over
the Internet.
"Flash" Plating. Electroless Plating
Flatpack. A part with two straight rows of leads (normally on 0.050
inch centers) that are parallel to the part body.
Fluorescence. The process by which incident electromagnetic
radiation induces atomic ionization. As a result of ionization,
electrons from higher level orbitals drop (cascade) to lower orbitals,
and energy is released by the atom in the form of X-ray photons.
Feature. A conductive pattern on the printed circuit board.
Feeder. A machine that supplies tape and reel components in the
proper orientation and sequence for picking by a pick and place head.
Feeder, Intelligent. A feeder with a control system intended to
reduce set-up and inventory control errors.
Feeder, Tray. A machine that supplies tray components in the proper
orientation and sequence to a pick and place head.
FEP. Fluorinated Ethylene Propylene
FIB. Focused Ion Beam
Fid. Fiducial
Fiducial. A feature of the printed circuit board used to provide a
common measurement point for all steps in the assembly process.
Fiducial Camera. Camera, Fiducial
Fiducial, Global. A fiducial mark used to locate the position of all
circuit features on a printed circuit board.
Fiducial, Local. A fiducial mark used to locate an individual
component.
Fillet. A build-up of material between two surfaces. In reference to
soldering, a fillet is the solder built-up between the component and the
conductor. Ideally, the fillet is smooth and concave.
Film Tension. The greatest longitudinal stress a film can bear
without tearing apart.
Fine Pitch (1) In SMD: Surface mounted components with a lead or
termination pitch of 0.025 (some say 0.020) inch or less. (2) In BGA:
With standard pitch is 1.27 (some say 1.0) mm, anything less requires
special handling. (3) The pitch that is difficult to place (requires a
cost adder) in manufacturing (assembly) practice.
Firmware. A program permanently recorded in ROM; it is effectively a
piece of hardware that performs software functions.
First Pass Yield. The percent of finished assemblies not requiring
rework.
Flat Pack. An integrated circuit package with leads on two or four
sides with either gull wing or flat leads.
Flat Wave. Laminar Wave
Flex. Flexible Printed Circuit Board
Flexible Printed Circuit Board. A printed circuit board laminate
made dielectric polymer film, adhesive, and conductive foil.
Flip Chip. A COB technology that has bumps attached to the silicon
die, is flipped, and mounted directly to a printed circuit board.
Flood Bar. A device on a screen printer that drags the paste back to
the starting point after the squeegee has made a stroke to prepare for
the next stroke.
Flux. A chemically-active compound which, when heated, removes minor
surface oxidation, minimizes oxidation of the basis metal, and promotes
the formation of an intermetallic layer between solder and basis metal.
Various flux types include: low residue, organic acid, rosin, rosin
activated, rosin mildly activated.
Flux Activation Temperature. The temperature at which flux is active
enough to remove oxides from the metals being joined.
Flux Activity. The ability of materials (activators) in the flux to
remove corrosion and make the surface solderable.
Flux, Inorganic. An aqueous flux solution of inorganic acids, such
as hydrochloric or phosphoric, and halides. These fluxes are very
corrosive and not recommended for electronic assembly.
Flux, Low Residue. No-clean flux. "Leave on" flux. Low residue
fluxes usually have lower solids content (less than 5%) than high-solids
rosin fluxes. Their primary activator materials are weak organic acids
(adipic or succinic acid). No clean residues are benign on a board
surface and act as electrical insulators. These fluxes can be either
solvent (usually isopropanol) borne or water borne in the case of
volatile organic compound (VOC) free no clean fluxes.
Flux, No-clean. Flux, Low Residue
Flux, Organic Acid (Type OA). Water Soluble Flux. Organic acid
fluxes have active ingredients such as organic hydrohalides, amines, and
amides. These fluxes are water soluble since they contain no rosin. Good
cleaning is critical with these flux types since their residues are
corrosive and electrically conductive.
Flux, Resin. A flux primarily is composed of natural resins other
than rosin types and/or synthetic resins.
Flux, Rosin (Type R). Typically, these fluxes are made up of 60%
solvent and 40% solids. This flux type’s peak capability is around 262°C
(500°F). At this temperature, rosin begins decomposing into reducing
gases. Above 346°C (650°F), the flux becomes inactive and polymerizes.
Flux, Rosin Activated (Type RA). Rosin activated flux typically
contains 1% to 5% activators. RA flux is used in applications when RMA
is not strong enough. For military purposes, RA flux use usually is
limited to component tinning of sealed devices and solid wire. When
warm, these fluxes can conduct electricity and can leave residues that
can cause corrosion or shorting path formation between conductors.
Flux, Rosin Mildly Activated (Type RMA). When solder surfaces
require a more active flux than rosin flux, flux manufacturers add
chemical compounds called activators to the rosin. RMA flux may contain
a variety of activators in amounts less than 1%. Limits are placed on
their electrical and chemical properties before and after soldering
Flux, Water Soluble. Flux, Organic Acid
Fluxer. The section of a wave solder machine that applies flux to a
printed circuit assembly. Foam, spray, and wave fluxers are common.
Fluxer, Foam. Equipment for applying flux by bringing printed
circuit assemblies in contact with the surface of a foam head of flux
created by bubbling flux through a porous material.
Fluxer, Spray. Equipment for applying flux to a printed circuit
board by passing the board over a fine mist of flux created by spray
nozzles or ultrasonic transducers.
Fluxer, Wave. Equipment for applying flux by bringing printed
circuit assemblies in contact with the surface of continuously flowing
and circulating flux.
Fluxing. Using a fluxer. Applying flux.
FMEA. Failure Mode Effect Analysis
Foam Fluxer (ing). Fluxer, Foam
Focused Ion Beam (FIB). A "milling machine" that uses ions. Like a
SEM, a sample is put in a chamber under vacuum, beneath a column which
scans a focused beam of charged particles over the sample surface. In a
FIB, the charged particles are ions (typically gallium) generated by a
liquid metal source. The ions collide with and sputter away atoms of the
sample in the scanned region. This beam can slice into the sample with
great accuracy. Like in an SEM, a detector in the chamber collects
secondary species (ion or electron) for imaging. Resolution is fine
enough to image ICs.
Foot Angle. The angle of the lead foot after lead forming relative
to the surface of the bottom of the component.
Foot Length. The part of the component lead that contacts the
bonding pad on the substrate.
Footprint. (1) The area occupied by a device mounted on a substrate.
(2) The area a machine takes up in a production area.
Fourth-Generation Environment (4GE). Fourth-Generation Language
Fourth-Generation Language (4GL). A computer language instructing
the computer at a higher-level language abstraction than traditional
high-level programming languages. Any computer language that does not
require traditional input/process/output logic falls into this category.
FPT. Fine Pitch Technology.
Fractured Solder Joint. Solder Joint, Fractured
Frame. In inspection, the total area of the picture that is scanned
by a camera.
Frame Grabber. A device that digitizes an image and stores it in a
computer's memory.
Frame Rate. The frequency at which an image is completely updated on
a display monitor.
Frame Relay. A technology for transmitting data packets in
high-speed bursts across a digital network.
Freeze (ing). Solidification of a solder joint.
FR-4. A relatively inexpensive glass epoxy substrate.
FTP. File Transfer Protocol
Functional Test. Test, Functional
Fuzzy Logic. A method used to model linguistic expressions that have
non-binary truth values such as PID algorithms in process control.
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G
GaAs. Gallium Arsenide
Gantry. A mount for moving a pick and place, inspection, or dispense
head in the x-y direction on a frame.
Gauge R&R. A statistical measurement technique that calculates
the inaccuracy of a measurement device according to gauge repeatability
and gauge reproducibility.
Gauge Repeatability. Equipment variation. The variability of a gauge
when used to make repeated measurements under carefully controlled
conditions.
Gauge Reproducibility. Appraiser variation. A statement of gauge
precision when used by different operators.
GelPak. A matrix tray style feeder without pockets, that consists of
a tacky gel over a mesh. The components are placed in a regular array on
the tray and are held in place by the tacky gel. When picking
components, vacuum is applied through the bottom of the tray, pulling
the gel through the mesh and releasing the die.
GEM. General Equipment Module
General Equipment Module (GEM). A protocol for communicating between
production equipment.
Gerber® Data.
Used in directing a photoplotter during printed circuit board artwork
fabrication.
GHz. Gigahertz
Glass Fabric. Glass yarns woven in a specific pattern.
Glass Transition Temperature (Tg). The temperature when a material
changes from hard, brittle, and glasslike to soft and rubbery and looses
considerable mechanical strength.
Global Fiducial. Fiducial, Global
Globtop. Encapsulant
Gold Flash. An extremely thin layer of gold with a thickness
measured on the molecular level which is either electroplated or
chemically plated onto a surface.
Golden Board. A known good printed circuit board used for evaluating
other printed circuit boards or assemblies.
Green Strength. The holding power of a paste or adhesive before it
is set or cured.
Ground. A mass such as earth, a ship, or a vehicle hull, capable of
supplying or accepting a large electrical charge.
Ground, Hard. A connection to "green wire" electrical ground either
directly or through low impedance.
Ground Plane. A relatively large mass of metal on a printed circuit
board used as an electrical ground or shield.
Ground, Soft. A connection to ground through an impedance
sufficiently high to limit current flow to safe levels for personnel
(normally 5 milliamperes). Impedance needed for a soft ground is
dependent upon the voltage levels which could be contacted by personnel
near the ground.
Gull Wing. Component leads that flare outward from the part body.
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H
Halide. A compound of chlorine, bromine, or iodine, often added to
flux as activators. Halides can form corrosive solutions.
Halide Content. The ratio of free chlorine and bromine ions to
solids in a flux.
Haloing. Mechanically-induced fracturing or delaminating on or below
the surface of the base printed circuit board material; it is usually
exhibited by a light area around holes, other machined areas, or both.
Hard Ground. Ground, Hard
Hardner. The part that makes a thermosetting polymer cure.
HASL. Hot Air Solder Leveled
HASS. Highly Accelerated Stress Screening
HAST. Highly Accelerated Stress Testing
HDI. High-Density Interconnect
Head. An element of a pick and place machine that positions (i.e.,
rotates, feeds-back x-y location, and moves on z axis) nozzles to pick
and place components.
Head, Self-Planarizing. A mechanism integrated into the head of an
outer lead bonder that allows the bottom surface of the thermode blades
to adjust to the plane defined by the surface of the substrate.
Heat Resistance. The temperature at which a bond subjected to a load
fails.
Hermetic. The sealing of an object so it is airtight.
HFC. Hydrofluorocarbons
HFE. Hydrofluoroethers
Hipot. An electrical test to measure the voltage breakdown of a
substrate or material.
High Temperature Solder. Solder, High Temperature
Home Plate. A five sided, two dimensional, closed shape where three
equal length sides form a cube with one side removed and two additional
equal length sides that form interior angles of 135? 90? and 135? A
picture is worth a thousand words.
Hook Terminal. Terminal, Hook
Hot Air Solder Leveled (HASL). A printed circuit board fabrication
process that applies an oxidation preventing solder coating to copper
pads on the printed circuit board. Solder Leveling.
Hot Bar Soldering. Soldering, Hot Bar
Hot Tack. The ability of hot melts to have holding power even while
in the liquid hot state.
HTTP. Hypertext Transfer Protocol
Hybrid. A package where integrated circuits and discrete components
are attached directly to a common substrate. Connections between the
components are formed on the surface of the substrate and some
components such as resistors and inductors may be fabricated directly
onto the substrate.
Hydrolysis. Decomposition of a substrate by reaction with water.
Hydrophilic Solvent. Polar Solvent
Hydrophobic Solvent. Non-Polar Solvent
Hydroscopic. The capacity of a material to absorb and retain
moisture from the ambient air.
Hypertext Transfer Protocol (HTTP). The protocol that negotiates
document delivery to a Web browser from a Web server.
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I
I Lead Package. A SMT lead that is formed so the end of the lead
touches the pad.
IC. Integrated Circuit
ICT. In-Circuit Test(ing)
IL. Intermetallic Layer
IMAPS. International Microelectronics and Packaging Society
Immiscible. Incapable of mixing or obtaining homogeneity.
Immunity. The property of a piece of equipment that enables it to
reject an electrical disturbance.
Inclusion
Index Time. The time required for a feeder to advance the next
component on a tape to the pickup position.
Inert. Inactive. Static
Inert Atmosphere. Replacing oxygen with a noble gas, typically
nitrogen, to increase the flexibility of a soldering process.
Inert Gas. Noble Gas
Infrared. (1) Transfer of energy (heat) by radiation. (2) Transfer
of long wavelength light.
InfraRed (IR) Reflow. Reflow Soldering, Infrared (IR)
Injection Molded Boards. Printed circuit boards made by molding
filler-reinforced resins into a desired shape. Routing and through hole
metallizations are performed by seeding and plating, or by printing. An
alternative approach is to transfer mold the interconnect directly onto
the injection molded cards.
Inner Layer. Internal Layer
Inorganic. Compounds without carbon.
Inorganic Flux. Flux, Inorganic
Inorganic Substrate. Substrate, Inorganic
Institute For Interconnecting And Packaging Electronic Circuits
(IPC). A research and standard setting organization focused on
fabricating and assembling printed circuit boards.
Insufficient Solder Joint. Solder Joint, Insufficient
Insulation. (1) A non-conductor used to isolate or prevent contact
between conductors. (2) Electrostatic Insulating Material.
Integrated Circuit (IC). A microcircuit that consists of
interconnected elements on a single substrate, usually silicon, to
perform an electronic circuit function.
Integration. The state in which all aspects of plant-wide operations
are tied together in a continuous loop of information.
Intelligent Feeder. Feeder, Intelligent
Interconnect. Wiring patterned in integrated circuits or printed
circuit board to connect different devices together.
Interlayer Connection. Connection, Interlayer. Via
Intermetalic Layer (IL). A compound formed at the interface of two
different metals.
Intermetalic, Tin Copper. When joining 63Sn/37Pb and other high tin
alloys with copper, two intermetallic compounds are formed. On the
copper side is Cu3Sn and on the solder side, the relatively rough and
irregular Cu6Sn5. The total thickness of the IL is usually 0.5-0.7 “m.
The intermetallic compounds of copper and tin form crystalline grains,
the structure of which is determined by the length and intensity of the
thermal interaction. Short reaction times form fine equiaxed grains,
which promote good solderability and solder joint strength. Long
reaction times result in coarse grains, and a thick IL. A thick IL gives
poor solderability and poor joint strength, both in t = o shear and
long-term reliability. The thickness of the IL depends on the
temperature, but will continue to grow even at ambient temperatures
(which on the absolute (°K) scale approaches 60% of the liquidous
temperature of 63Sn/37Pb solder). This becomes important when parts or
boards are solder coated or pre-tinned. During prolonged or improper
storage, the IL can grow through the surface, affecting solderability.
Internal Layer. A conductive pattern that is contained entirely
within a multilayer PCB.
International Organization For Standardization (ISO). An
international standard setting organization based in Geneva,
Switzerland.
Intrusive Soldering. Pin & paste
Invar. An alloy similar to bronze.
Inventory Management. The systematic determination of items and
quantities to be ordered; the coordination of order release and order
due dates; changes in the required quantities; and the rescheduling of
planned orders.
In-Circuit Test (ICT). Test, In-Circuit
Ion. A particle formed when an electron is added to, or subtracted
from, a neutral atom or group of atoms.
Ion Exchange. A reversible chemical process in which ions from an
insoluble permanent solid medium, the "ion exchanger" (usually a resin)
are exchanged for ions in a solution or fluid mixture surrounding the
insoluble medium. The superficial physical structure of the ion
exchanger is not affected. The direction of the exchange depends upon
the selective attraction of the ion exchanger resin for the certain ions
present and the concentrations of the ions in the solution.
Ion Implantation. The process by which dopants (i.e., phosphorus,
arsenic, or boron) are introduced in exact quantities into silicon. A
stream of ions of the dopants is created and then directed at a silicon
wafer at a precisely controlled velocity (energy), controlling both the
concentration and depth of the dopant.
Ionic Contaminant. An ionic, or polar compound that forms free ions
when dissolved in water, making the water a more conductive path.
Process residue such as flux activators, finger prints, and etching or
plating salts usually contain ionic contaminants.
Ionograph®. A
brand name for an instrument used to measure ionic contamination
(residues) on a printed circuit board.
IPA. Isopropyl alcohol
IR. (1) Infrared. (2) Insulation Resistance
IR Reflow. InfraRed Reflow. Reflow Soldering, Infrared (IR)
Iron. A soldering iron is a hand soldering tool.
ISO. International Organization For Standardization
ISO 9000 The "Quality System Management Standard" that
specifies the elements of a quality system.
ISO 14000 The "Environmental Management Standard" that
specifies the elements of a environmental control system.
Isopropanol. Isopropyl alcohol
Isotropic. Having properties that have equal value in all
directions.
ITRI. Interconnection Technology Research Institute
I/O. Input/Output
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J
JEDEC. Joint Electronic Device Engineering Council. The component
standardization group within EIA.
Jelly Bean Device. An integrated circuit containing a small number
of simple logic functions.
Joint. Solder joint. Termination
Jumper Wire. A wire added to a printed circuit assembly to complete
a circuit that was not included in the printed circuit board.
J-Lead. A lead, typically on plastic packages, which is rolled under
the package. A side view of the formed lead resembles the shape of the
letter J.
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K
Kapton ® A brand name of a polyimide film used as an electrical
insulation material with good thermal, mechanical, chemical, and
electrical properties.
Keepouts. Areas that are kept clear of any components.
keV. Kilo Electron Volts
KGB. Known Good Die
Known Good Board. Golden board.
Known Good Die (KGD). A die tested to meet requirements.
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L
Laminar Wave. A section of a dual wave soldering machine used to
solder through hole components and remove shorts on SMT components.
Laminate. A product made of two or more layers of materials.
Lamination. C-stage. A heat and pressure process used to consolidate
a stack of prepregs into a solid block. The term also refers to the
consolidation of a stack of laminates (with circuitry) to form a printed
circuit board.
Land. A pad.
Land, Lifted. Pad, Lifted.
Land Pattern. A combination of conductive patterns intended for the
mounting interconnection and testing of a particular component.
Lateral Edge. The longer side of a rectangular pad or printed
circuit board.
Laser. Light Amplification by Stimulated Emission of Radiation
Laser Cut Aperture. Aperture, Laser Cut
Laser Cut Stencil. Stencil, Laser Cut
Laser Soldering. Soldering, Laser
Lay-Up. In printed circuit board fabrication, stacking and
registering the layers of a multilayer printed circuit board.
LCC. Leadless Chip Carrier
LCCC. Leadless Ceramic Chip Carrier
Leaching. Dissolution of a metal coating into liquid solder. Nickel
barrier under-plating prevents the over-plating (usually gold or silver)
from leaching into the copper base.
Lead Forming. Shaping the lead into a specific shape or profile
required for placement or insertion and bonding.
Lead Frame. A sheet metal frame containing leads and a base to which
an integrated circuit is attached before packaging.
Lead Free Solder. An alloy of tin and another metal such as
antimony, bismuth, copper, magnesium, silver, zinc, or bismuth.
Lead, Part. The solid conductor attached to a part.
Lead Pitch. Pitch
Lead Plating. Plating, Lead
Lead Spacing. Pitch. The distance between the center of adjacent
leads.
Leaded Device. Electronic device with electrical leads extending
from the body of the package.
Leadless Device. Electronic device without electrical leads
extending from the body of the package. These packages could have solder
bumps or lands located on the package.
Leakage Current. A current that flows through or across an insulator
between two electrodes.
LED. Light-Emitting Diode
Leg Angle. The angle of the vertical portion of a lead with respect
to a plane perpendicular to the plane defined by the bottom of the
component.
Leg Length. The part of the component lead between the two bend
radii. The leg length is directly related to the overall lead form
height.
Legend. Silk screened circuit designations on a printed circuit
board.
Lifted Land (Pad). Land, Lifted
LEM. Light Emission Microscope
Liquid Photo-Imageable. Solder Mask, Liquid Photo-Imageable
Liquidous. The temperature when a metal or alloy is completely
liquid.
Lithography, Optical. A process which passes optical radiation,
usually ultraviolet, through a phototool and projects the pattern onto a
layer of resist coating the substrate material.
Lithography, X-Ray. Similar in principle to optical lithography, but
capable of constructing much finer features due to the shorter
wavelengths involved.
Local Fiducial. Fiducial, Local
Logic Chip. A chip which does computations, makes decisions, or
makes things happen. For example, the Intel Pentium microprocessor in a
computer is a logic chip and does mathematical computations, among other
things.
Low Residue Flux. Flux, Low Residue
Low Temperature Solder. Solder, Low Temperature
lm/m2. Lumens per square meter. A measure of light intensity.
LPI. Liquid Photo-Imageable (solder mask)
LR Flux. Flux, Low Residue
LSI. Large-Scale-Integration (Integrated Circuit)
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M
Management Information System. Computerized network used in
effectively structuring critical information in a form usable for
identification of inefficiencies.
Manual Assembly. An electronic assembly process carried out by an
operator primarily using hand tools, including a soldering iron.
Manufacturing Defects Analyzer (MDA). Test, Manufacturing Defects
Analyzer
Manufacturing Execution Systems (MES). A system that, rather than
focusing on measurements of material usage or process control, "centers
on the product itself as it moves through the plant on the way to the
customer."
Manufacturing Resource Planning (MRP). A software tool that enables
a manufacturer to plan, allocate, and track material and financial
resources for a production process.
Mask. A material applied to allow selective etching, plating, or
protection of the surface of a printed circuit board.
Material Safety Data Sheet (MSDS). A US OSHA standard format that
suppliers use to describe the hazards of the materials they provide for
use by others.
Material Requirements Planning. Manufacturing Resource Planning
Matrix Tray. Tray, Waffle
Microelectronics and Computer Technology Corp.
Multichip Module
MCM-C. Ceramic MCM
MCM-D. Deposition MCM
MCM-L. Laminated MCM
MCM-L/D, MCM-C/D. Combination MCMs
MCR. Molded Carrier Ring
MDA. Manufacturing Defects Analyzer
Mean Time Between Failures (MTBF). Average time an assembly or
machine is available to operate.
Mean Time To Repair (MTTR). Average time required to repair the
various problems of an assembly or machine.
Measling. (1) Discrete white spots below the surface of the base
material, usually caused by moisture, pressure, and/or thermally induced
stress. (2) A condition existing in the base material in the form of
discrete lighter spots of "crosses" below the surface of the base
material, which is a separation of fibers in the glass cloth at the
weave intersection.
Mechanical Adhesion. Adhesion, Mechanical
Mechanical Centering. Centering, Mechanical
MEK. Methyl Ethyl Keytone
MELF. Metal electrode leadless face is a cylindrical SMT package
form used for resistors and diodes.
Membrane Separation. A type of noncryogenic nitrogen generator.
Meniscus. The curved, upper surface of a liquid that is concave when
the containing walls are wetted by the liquid and convex when the
containing walls are not wetted by the liquid.
MES. Manufacturing Execution System
Mesh. The size of the holes on a screen used to sort powders.
Sorting sieves are dimensioned in holes per square inch.
Mesh Size. The number of openings per inch in a screen. For example,
a 325 mesh screen has 325 openings per inch.
Metal Content. The percentage weight of the solder alloy powder in
solder paste.
Metal-Core Boards. Boards built with a metallic core and an organic
or inorganic insulation on either sides of the core. The core could be
made of steel, stainless steel, aluminum, copper, or a laminate of
metals (in most cases copper Invar copper or copper tungsten copper).
The insulation of the core is done prior to metallization.
Metering Rolls. Successive rollers used to control the fabric to
resin ratio during the impregnation of resin onto glass fabric.
Methyl Ethyl Keytone (MEK). An US EPA prohibited material used in
printed circuit board fabrication.
mg. Milligram
mg/L. Milligram/Liter
MHz. Megahertz
Microsectioning. A destructive test showing an encapsulated cross
section of a part or assembly.
Micro BGA®
(µBGA®). A brand name for a fine pitch BGA.
Micro-Beam X-Ray Fluorescence (MXRF). X-Ray Fluorescence
Micron. Micrometer. An unit of length equal to one millionth of a
meter.
Microvia. A design technique aimed at reducing substrate (product)
size. A microvia is a via less than 150um in diameter, about a half the
size of common via, and normally blind. Laser drilling make microvias at
500X the speed of mechanical drills.
Migration. (1) Migration of adhesives from the interior to the
surface of a plastic. (2) Electrochemical Migration
Mil. One thousands of an inch.
MIS. Management Information System
Misalignment. Misregistration of the centerline of the component
lead with respect to the centerline of the pad on the substrate.
Misregistration. The lack of conformity between two or more patterns
or features.
Mixed Technology. Describes the assembly process used when pin
through hole, surface mount, and other mounting technologies on the same
printed circuit board.
MLB. Multilayer Board
Millimeter
Modification. The process revising the functional capability or
performance characteristics of a product to satisfy new acceptance
criteria. Modifications usually are required to incorporate design
changes that can be controlled by drawings, change orders, etc.
Molded Carrier Ring (MCR). IC with a plastic molded body and guard
ring to reduce damage to leaded surface mount packages caused by normal
handling. The guard ring also acts as a common form factor for the
development of automation such as test, burn in, and excise and form.
Mole®. A brand
name for a profiler.
Molecular Weight. The sum of the atomic weight of all atoms in a
molecule.
Montreal Protocol. In 1987, twenty-four countries, including the
United States and members of the European Economic Community signed the
Montreal Protocol to control CFC and Halon compounds, which are thought
to deplete the ozone layer of the Earth.
Mounting Hole. (1) Plated-Through-Hole (PTH). (2) A hole used in
mechanically mounting a printed circuit assembly to a housing.
Mouse Bite. A method of securing a breakaway tab to the printed
circuit board.
MRP. Materials Requirements Planning
MRP II. Manufacturing Resource Planning
MSDS. Material Safety Data Sheet
MTBF. Mean Time Between Failures
MTTR. Mean Time To Repair
Multichip Module. A modular package with both active and passive
devices in one package. Versions; MCM-L, MCM-C, and MCM-D; vary
according to substrate.
Multilayer Printed Circuit Board. A laminate with more than two
layers of copper foil.
Multilayer Substrate. Usually referring to cofired multilayer
ceramic substrates.
MXRF. Micro-Beam X-Ray Fluorescence
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N
NaCl. Sodium Chloride
Nailheading. In printed circuit board fabrication, the flaring of
internal connections.
Nd:YAG. Neodymium glass yttrium aluminum garnet (laser)
Needle. A dispensing tip.
Negative Resist. Resist, Negative
Net List. A list to groups of two or more points in a circuit design
that are electrically common.
Neutralizer. An alkaline chemical added to water to improve its
ability to dissolve organic acid flux residues.
nF. nanoFarad
Ni. Chemical symbol for the element nickel.
Nick. A cut or notch on a conductor or insulator.
Nickel Over Gold. Generally, Electroless Nickel - Immersion Gold
NIST. National Institute of Standards and Technology
Nitto Tape. Tape that sliced silicon wafers are placed on prior to
dicing.
Noble Gas. Helium, neon, argon, krypton, xenon, and sometimes radon.
Noble Metal. Metals; such as gold, silver, and platinum; which are
extremely inactive and are unaffected by air, heat, moisture, and most
solvents.
Node. An electrical connection of two or more components on a
printed circuit board.
Non-Activated. A natural or synthetic resin flux without activators.
Non-Ionic. Non-Polar
Non-Ionic Contaminant. A substance that neither forms free ions, nor
increases the conductivity of water.
Non-Polar. A substance does not ionize in water.
Non-Polar Solvent. A solvent that is not electrically conductive and
will dissolve non-polar compounds such as hydrocarbons and resins.
Non-Solder Mask Defined (NSMD) Pads. Pad, Non-Solder Mask defined
Nozzle. (1) A tool selected to interface between a pick and place
head and each particular part being placed. (2) Tip. A tool used in
dispensing adhesives.
No-Clean Flux. Flux, No-Clean.
NSMD (Pads). Non-Solder Mask Defined
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O
OA Flux. Flux, Organic Acid. A water soluble flux.
Object-Oriented Programming. Programming based on a package of
information and descriptions of procedures that communicate by passing
messages.
ODBC. Open Database Connectivity
ODP. Ozone Depletion Potential
Off Contact (Printing). Printing with a separation between the
screen or stencil and the substrate.
Off-Gassing. Out-Gassing
Omegameter®. A
brand name for an instrument used to measure ionic contamination
(residues) on a printed circuit board.
OMPAC. Over Molded Plastic Array Carrier
On Contact (Printing). Printing with the screen or stencil touching
the substrate.
OOP. Object-Oriented Programming
Open. A loss of electrical continuity caused by (1) a break in a
trace path on a printed circuit board or (2) solder failing to bridge
the gap between lead termination and the pad.
Open Database Connectivity (ODBC). A database connectivity standard
written and defined by Microsoft that allows an application to interact
with any database that supports the ODBC standard.
Open Systems (OS). An approach to computing that allows the
interconnectability of systems based on compliance with established
standards.
Operations. A series of processes required to provide product or
services meeting certain requirements. Printed circuit board fabrication
is an operation.
Operator Interface. A physical link between the human operator and a
computer system, typically consisting of a graphical representation.
Optical Lithography. Lithography, Optical
Organic. Materials based on carbon compounds. All life forms are
organic. Organic fluxes are primarily composed of organic materials
other than rosin or resin.
Organic Resist. Resist, Organic
Organic Solder Preservative (Protectant) (OSP). (i.e., Entek,
Imidazole) A coating applied during printed circuit board fabrication to
protect copper features from oxidation.
Organic Solvent. A solvent for organic materials, such as organic
resists.
Organic Substrate. Substrate, Organic
OSHA. Occupational Safety and Health Administration
Osmosis. The natural tendency for water to spontaneously pass
through a semipermeable membrane separating two solutions of different
concentrations (strengths). The water will naturally pass from the
weaker (less concentrated) solution to the stronger (more concentrated)
solution of a dissolved substance.
OSP. Organic Solder Preservative (Protectant)
Out-Gassing. The release of volatile parts from a substance when
placed in a vacuum environment.
Overheated (Solder) Joint. Solder Joint, Overheated
Over Molded Plastic Array Carrier (OMPAC). A brand name for plastic
ball grid array.
Oxidation. Tarnish. The absorption of oxygen into the surface of
some metals. Oxygen "burns" or oxidizes all material with which it comes
in contact. Oxides are thermal insulators and resist solder wetting.
Oxide Content. The amount of oxides present on the surface of solder
powder.
Ozone Depletion Potential (ODP). A relative index indicating the
extent to which a chemical product may cause ozone depletion.
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P
Pa. Pascal
Packaging Density. The number of components, interconnections, and
mechanical devices per unit volume.
Pad. Land. A portion of a conductive pattern used as a termination
area. Metal surrounding a hole on a printed circuit board.
Pad, Dummy. A pad in excess of component interconnection
requirements.
Pad, Lifted. A pad that has lifted or separated from the base
material, whether or not any resin is lifted with the pad.
Pad, Non-Solder Mask Defined. Pads with spacing that does not allow
solder (usually bumps) on the pads to contact the adjacent solder mask.
Pad, Solder Mask Defined. Pads with spacing that allows solder
(usually bumps) on the pads to contact the adjacent solder mask.
Pad, Test. A 0.040 inch square pad on the surface of a printed
circuit board, used to make electrical contact with a circuit node for
testing purposes.
Pallets (Solder). A tool for positioning a printed circuit board
during a process. Typically, pallets are used during wave soldering and
flex and PCMCIA processing.
Panel. An array of, usually identical, separate circuits fabricated
on a single substrate.
Panelized. Panel
Part. An element of an assembly, or subassembly that is not normally
subject to further subdivision or disassembly without destruction of
designed use. Examples are: Printed wiring board, resistor, integrated
circuit.
Pascal. A unit of pressure equal to one newton per square meter.
Passive Hold-Down. Holding the component lead in contact with the
bonding pad by pressing on the body of the component during the
soldering process to ensure intimate contact between the lead and
bonding pad. Intimate contact is important for proper heat transfer
through the lead to reflow the solder. This is commonly used in laser
and hot gas soldering.
Paste. Solder Paste
Paste In Hole. Pin & Paste
Pb. Chemical symbol for the element lead.
PBGA. Plastic Ball Grid Array
PCA. Printed Circuit Assembly
PCB. Printed Circuit Board
PCMCIA. Personal Computer Memory Card Industry Association
Peel Back. In wave soldering, when the solder of the wave breaks
away from the printed circuit board and returns to the wave.
Peel Back Force. The force required to remove the mylar cover tape
on a tape and reel carrier.
Peel Strength. A test of the adhesion between the lead and the
bonding pad after it has been soldered. It is determined by peeling the
component lead off the bonding pad using special fixturing on a pull
tester.
Peel-Away Speed. Stencil, Peel-Away Speed.
Penetration. The entering of an adhesive into a substrate.
Perforated Terminal. Terminal, Pierced (Perforated)
Personal Computer Memory Card Industry Association (PCMCIA). A trade
organization formed to promote interchangeability of cards among a
variety of computer products.
pF. picoFarad
PFMEA. Process Failure Mode Effect Analysis
PGA. Pin Grid Array
pH. A measure of alkalinity and/or acidity of a liquid.
Photolithography. The photographic process used to transfer circuit
patterns onto a semiconductor wafer. This is done by projecting light
through a patterned reticle, onto a silicon wafer covered with a
photoresist.
Photoplotting. Lithography. A method of creating artwork from
computer files.
Photoresist. Resist. A light sensitive material, liquid or a
laminated dry film, which when selectively exposed to light, masks off
areas of the design that can be etched away.
Phototool. A photographic material used to produce a circuit design
pattern on a substrate. Artwork.
Physical Vapor Deposition (PVD). Deposition of thin films by
physical means as opposed to chemical (like chemical vapor deposition).
This is most often used for deposition of metals. The most common form
of PVD is sputtering.
PID. (1) Photo-Imageable Dielectric. (2) Proportional Integral
Derivative (Controller).
Pick And Place (P&P). An assembly operation where a machine that
orients and places components on their pads on a substrate prior to
soldering.
Pick And Place Head. Head
Pierced Terminal. Terminal, Pierced (Perforated)
Pin Grid Array (PGA). A PTH package with a large array of leads
protruding perpendicular to one side of a component package.
Pin & Paste. Using SMT processes to solder through hole parts.
Pinhole. (1) Soldering: A solder connection with a small hole
penetrating from the surface of the solder to a void of indeterminate
size within the solder connection. (2) Printing: A void that receives no
ink, paste, or gel during printing.
Pink Ring. In fabrication, a cosmetic defect in which a pink area is
seen on an internal copper feature surrounding a plated hole. This
appearance is caused by the presence of clean copper, free of the copper
oxide coating used an adhesion promoter between internal copper feature
and prepreg resin.
Pin-Through-Hole (PTH). A manufacturing technology, where the
slender wire leads of components are inserted through the holes of the
printed circuit board.
Pips. Location pegs on components, such as connectors and sockets,
used for manual placement and for automatic placement when precise
location of the part is required.
Pit. A relatively small recess in the solder surface, the bottom of
which is visible from all angles of vision.
Pitch. (1) The center-to-center spacing between the leads of a
component. (2) Distance between pockets on a carrier tape. Pitch varies
according to tape width and components packed on the tape. (3) The
center to center distance of two adjacent sprocket holes.
Placement. The manual, semiautomatic, or automatic location of a
component, device, or chip at its intended position.
Placement Head. Head
Planarity. Warpage. Substrate surface flatness.
Plasma. A gaseous state in which the atoms or molecules are
dissociated to form ions. In semiconductor processing, plasmas are used
for etching and thin film deposition. In everyday life, plasmas are used
to give light - in fluorescent light bulbs, neon lamps, and blue-light
insect "zappers."
Plasma Cleaning. Cleaning, Plasma
Plasma Etching. Dry Etching. Using a plasma to etch a semiconductor
layer. The plasma contains highly excited molecules (reactive ions)
which easily react chemically. There is also a physical bombardment
mechanism in that the ions are accelerated towards the wafer with an
electric field.
Plastic Ball Grid Array (PBGA). A Ball Grid Array (BGA) package of
high Tg material substrate and encapsulated with either a plastic
overmold or globtop. An array of eutectic (63Sn/37Pb) 0.77 mm diameter
balls provide the interconnection to the printed circuit board. These
balls reflow during package and printed circuit board assembly and
provide a 50 mm gap or standoff between the chip carrier and the glass
epoxy board.
Plastic Leaded Chip Carriers (PLCC). A SMT package with 50 mil
spaced J-leads on all four sides that have the same dimensions.
Plastic Range. The temperature range of a molten metal when the
metal is neither solid nor liquid.
Plated-Through-Hole (PTH). A plated-through hole is one formed by a
deposition of metal on the inside surface of a through-hole. Also known
as a supported hole. The configuration is used to provide additional
mechanical strength to the soldered termination or to provide an
electrical interconnection on a multilayer printed circuit board.
Plating, Additive. A process in which the conductive, resistive, and
insulating materials are successively plated to define traces, pads, and
elements.
Plating, Electroless. Plating as the result of chemical action
(without any external electric current).
Plating, Electrolytic. Plating deposited by application of
electrical current.
Plating, Lead. The metal coating on a component lead. Common lead
plating materials are pure tin (Sn), pure gold (Au), and eutectic
tin/lead solder (63%Sn/37% Pb).
Plating, Tin Lead. In printed circuit board fabrication, an
electroless plating process that coats exposed areas of copper on a
circuit board with a layer of tin lead alloy to prevent the copper from
oxidizing.
PLC. Programmable Logic Controller
PLCC. Plastic Leaded Chip Carriers
PLD. Programmable Logic Device
Plowing. In printed circuit board fabrication, the furrows in the
walls of a drilled hole.
Plug (ing). A printed circuit board fabrication process that fills
vias to prevent heat conduction and chemical transport through the via
and to allow vacuum hold-down during automated testing.
Pogo®. A brand
name for a spring loaded test probe.
Poise. A centimeter-gram-second unit of viscosity.
Polar Solvent. A solvent that can dissolve polar compounds, such as
inorganic salts, but cannot dissolve non-polar compounds, such as resins
and hydrocarbons.
Polyester Resin. A polymer in which the structural units are linked
by ester grouping.
Polyimides. Thermosetting ring chain polymers characterized by -NH
group, used as a dielectric.
Polyimide Resin. A nonconductive polymer in which the structural
units are linked by amide grouping.
Polymer. (1) A chemical compound or mixture of compounds formed by
polymerization. (2) Compounds of very high molecular weights that are
made up of a large number of simple molecules which have reacted with
one another.
Polymerization. A chemical reaction in which two or more small
molecules continue to form larger molecules that contain repeating
structural units of the original molecules.
Polymerized Rosin. Rosin that has reacted with itself during the
course of a soldering operation.
Popcorning. When moisture held with a plastic part vaporizes and the
pressure cause cracks in the part.
Porous Solder Joint. Solder Joint, Porous
Portability. The ability to use and migrate software across
different platforms.
Positive Resist. Resist, Positive
Potato Chip (ping). When a printed circuit board a warps or curls
after it has been reflowed or wave soldered and resembles a potato chip
Potlife. Time a liquid resin remains workable after catalysts,
hardners, etc are added.
Potting. Encapsulating
Potting Compound. An electrically nonconductive compound used to
partially encapsulate or for a filler between parts, conductors, or
assemblies.
PPM. Parts per million
PQFP. Plastic Quad Flat Package
Preform (Solder). Solder Preform
Preflow. Soak. The portion of a reflow profile after preheat and
before the reflow spike occurs. During this time, the temperature of the
metals being joined is allowed to equalize.
Pregel. In fabrication, small white spots just below the surface of
the laminate. This can be caused by premature curing of the resin during
the lamination process.
Preheat. Heating from ambient at a predetermined rate to avoid
thermal shock.
Prepreg. Pre-impregnated materials are a combination of fiber and
resin to create a material that is stronger than either of its
constituents alone.
Primary Side. The side of the printed circuit board that contains
the most or more complex components.
Print Head. The assembly on a stencil printer that holds the
squeegee in place.
Printed Circuit Assembly (PCA). The bare printed circuit board with
components and associated hardware and materials.
Printed Circuit Board (PCB). A pattern of conductors printed
(screened) onto the surface of an insulating base to provide
interconnection for parts.
Printed Wiring Assembly (PWA). Printed Circuit Assembly
Printed Wiring Board (PWB). Printed Circuit Board
Pressure Swing Adsorption. A type of noncryogenic nitrogen
generator.
Probe. (1) A rigid, pointed, metallic, wire-shaped device used for
making electrical contact to a circuit pad for electrical test purposes.
(2) A metal s