"Do
You Speak Flex-Speak?"
It's common for every industry to have its special vernacular
and this can make customer/supplier communication difficult. Gained mostly
by experience and frustration, we eventually learn each other's jargon.
Lenthor Engineering is no different with its flex-speak, names of materials,
processes and product conditions that are not used outside of our industry.
Even more confusing can be two different industries that each use a different
word or phrase for the same thing!
We would like to do our part to both reduce your frustration
and add to your experience by sharing with you some of the terms used
in flex circuit manufacturing. You don't need to memorize them, but just
by seeing the words and their meaning, your understanding in conversations
will improve. And in our next issue, we will attempt to share a list of
the common synonyms used in our industry, like trace, line, circuit, track,
conductor… well, you get the idea.
By the way, we are offering some nice "get out of jail
free" promotions for first time customers and existing customer's blanket
orders that will save you the premium charges for faster deliveries. You
can reach your Lenthor Sales Account Manager for more information or call
me at (408) 957-3491 and I'll tell you more about it.
Thank you for taking the time to read our newsletter
and I appreciate any thoughts you have for improving its usefulness to
you.
Dale Baird
V. P. Sales and Marketing
Lenthor Engineering LLC
"Terms and Definitions"
Single-Sided Flex Circuits
Single-sided flexible circuits are the most common type in production
today. They are also the construction most often employed and best suited
to dynamic flexing applications. Their construction consists of a single
patterned conductor layer on a flexible dielectric film. Termination features
on these circuits are accessible only from one side. Single-sided flex
circuits can be fabricated with or without such protective coatings as
cover layers or cover coats. While many different metal foils can be used
as the conductor, copper foil is the most common.
Dual Access Flex Circuits
Dual Access flex circuits (also known as back bided flex circuits), contain
only a single conductor layer, but are processed to allow access to the
conductors from both sides. This construction is often employed in IC
packaging.
Double-Sided Flex Circuits
Double-sided flex circuits contain two conductor layers and can be produced
with or without plated-through holes, depending on design requirements.
Two-metal layer flex circuits will likely see increased use in chip packaging,
as operating frequencies continue to rise and the need for controlled
impedance constructions increases.
Multilayer Flex Circuits
Flex circuits that have three or more conductor layers are referred to
as multilayer flex. The layers of the circuit are interconnected with
plated-through holes.
Rigid-Flex Circuits
Rigid-flex circuits are a hybrid construction, consisting of rigid and
flexible substrates laminated together into a single package and electrically
interconnected by means of plated-through holes. Such flexible circuit
types have also enjoyed tremendous popularity among military product designers,
but, in recent years, this type of construction has made gains in the
commercial world, as well. Rigid-flex boards are normally multilayer designs,
but double-sided (two-metal layer) constructions are possible, as well,
and, in fact, have been selected for certain microelectronic chip-packaging
applications, most notably in the construction of hearing aids.
Access Hole
A series of holes in successive layers of a multilayer board each set
having their centers on the same axis. These holes provide access to the
surface of the land on one of the layers of the board.
Acrylic Adhesive
An adhesive used to bond Multi-layered flex together and also used as
part of the coverlay used on flex layers / boards. This is a polyimide
based material with an Er of 3.7.
Anchoring Spur
An extension of a land on a flexible printed board that extends beneath
the coverlay to assist in holding the land to the base material.
Annular Ring
That portion of conductive material completely surrounding a hole. This
is found on inner and outer layers.
Artwork
An accurately-scaled configuration that is used to produce the “Artwork
Master” or “Production Master.”
Artwork Master
An accurately-scaled, usually 1:1, pattern that is used to produce the
“Production Master”.
Aspect Ratio (Hole)
The ratio of the length or depth of a hole to its preplated diameter.
B-Stage
An intermediate stage in the reaction of a thermosetting resin in which
the material softens when heated and swells, but does not entirely fuse
or dissolve, when it is in contact with certain liquids.
Back-Bared Land
A land in flexible printed wiring that has a portion of the side normally
bonded to the base dielectric material exposed by a clearance hole.
Bake Out
Subjecting a product to an elevated temperature in order to remove moisture
and unwanted gasses prior to certain steps in the printed board manufacturing
process or prior to final coating.
Base Material
The insulating material upon which a conductive pattern may be formed.
(The base material may be rigid or flexible, or both. It may be a dielectric
or insulated metal sheet.)
Base Material Thickness
The thickness of the base material excluding conductive foil or material
deposited on the surfaces.
Basic Dimension
A numerical value used to describe the theoretical exact location of a
feature or hole. (It is the basis from which permissible variations are
established by tolerance on other dimensions in notes or by feature- control
symbols.)
Bed-of-Nails Fixture
A test fixture consisting of a frame and a holder containing a field of
spring-loaded pins that make electrical contact with a planar test object.
Blank
A processed piece of base material or metal- clad base material that has
no circuitry and is used to adjust the overall thickness of a printed
circuit board.
Blind Via
A via extending only to one surface of a printed board.
Blister
Delamination in the form of a localized swelling and separation between
any of the layers of a lamination base material, or between base material
and conductive foil or protective coating.
Board Thickness
The overall thickness of the base material and all conductive materials
deposited thereon.
Bond Enhancement Treatment
The improvement of the adhesion of a metal foil surface to an adjacent
layer of material to which it is being attached. We use Cobrabond for
this here.
Bond Strength
The force perpendicular to a board’s surface required to separate
two adjacent layers of the board, expressed as force per unit area.
Border Area
The region on a base material that is external to that of the end-product
being fabricated within it.
Brominated Epoxy
An epoxy resin containing chemically-bound bromine which is added to act
as a flame retardant.
Buried Via
A via that does not extend to the surface of a printed board.
Butter Coat
An increased amount of resin on the outer surface of a base material.
Button Print and Plating
This is where the pad and holes are imaged and plated in lieu of the entire
layer pattern. This is typically done on flex product to reduce cracking
of the signals caused by hydrogen embrittlement which is introduced during
the electro plating process.
C-Staged Resin
A resin in its final state of cure.
Cap Lamination
A process for making multilayer printed boards with surface layers of
metal-clad laminate bonded in a single operation.
Capability Performance Index (Cp)
The ratio of the measured performance of a process compared to specified
limits.
Capacitance
A measure of the ability of two adjacent conductors separated by an insulator
to hold a charge when a voltage is impressed between them.
Carrier (Foil)
A temporary support medium that facilitates the handling of thin and soft-metal
foils.
Catalyst (Resin)
A chemical that is used to initiate the reaction or increase the speed
of the reaction between a resin and a curing agent
Cause-and-Effect Diagram
A problem solving tool that uses a graphic description of various process
elements in order to analyze potential sources of process variation.
Characteristic Impedance
The resistance of a parallel conductor structure to the flow of alternating
current (AC), usually applied to high speed circuits, and normally consisting
of a constant value over a wide range of frequencies.
Check List
A compilation of the specified criteria that may be evaluated during an
audit or inspection.
Check Sheet
A form that is used for data collection.
Circuit
A number of electrical elements and devices that have been interconnected
to perform a desired electrical function.
Circumferential Separation
A crack or void in the plating extending around the entire circumference
of as plated through hole, a solder fillet around lead wire or eyelet,
or the interface between a solder fillet and a land.
Clad
A condition of the base material to which a relatively-thin layer or sheet
of metal foil has been bonded to one or both of its sides, e.g. “a
metal-clad base material.”
Clearance Hole
A hole in a conductive pattern that is larger than and coaxial with a
hole in the base material of a printed board.
Coefficient of Thermal Expansion (CTE)
The linear dimensional change of a material per unit change in temperature.
Compensated Artwork (Scaling)
Production master or artwork data that has been enlarged or reduced in
order to meet the needs of subsequent processing requirements.
Component Hole
A hole that is used for the attachment and/or electrical connection of
component terminations, including pins and wires, to a printed board.
Computer Numerical Control (CNC)
A system that utilizes a computer and software as the primary numerical
control technique.
Computer-Aided Design (CAD)
The interactive use of computer systems, programs, and procedures in the
design process wherein, the decision-making activity rests with the human
operator and a computer provides the data manipulation function.
Computer-Aided Manufacturing (CAM)
The interactive use of computer systems, programs, and procedures in various
phases of a manufacturing process wherein, the decision-making activity
rests with the human operator and a computer provides the data manipulation
functions
Conductor
A single conductive path in a conductive pattern.
Conductor Base Spacing
The spacing between conductors at the plane of the surface of a base material.
Conductor Base Width
The width of a conductor at the plane of the surface of a base material.
Conductor Spacing
The observable distance between adjacent edges (not center-to-center spacing)
of isolated conductive patterns in a conductor layer.
Conductor Spacing Line
The observable distance between adjacent edges (not center-to-center line)
of segments of conductive patterns in a conductor layer.
Conductor Thickness
Thickness of a conductor including additional metallic coatings but excluding
non-conductive coatings.
Conductor Width
The observable width of a conductor at any point chosen at random on a
printed board as viewed from directly above unless otherwise specified.
Cost of Quality
The money spent in the creation, control, and evaluation of quality and
the consequences of the failure to meet specified requirements.
Cover Coat
*see “Cover Lay.”
Cover Lay (Flexible Circuit)
The layer of insulating material that is applied covering totally or partially
over a conductive pattern on the outer surfaces of a printed board.
Crack, Foil
A break or separation that extends partially or completely through a layer
of metallic foil.
Crack, Plating
A break or separation that extends partially or completely through a metallic
coating(s), its overplate, or both.
Crazing (Base Material)
An internal condition that occurs in reinforced laminate base material
whereby glass fibers are separated from the resin at the weave intersections.
(This condition manifests itself in the form of connected white spots
or crosses that are below the surface of the base material.) It is usually
related to mechanically-induced stress.
Crosshatching
The breaking up of large conductive areas by the use of a pattern of voids
in the conductive material.
Date Code
Marking of products to indicate their date of manufacture.
Delamination
A separation between plies within a base material, between a base material
and a conductive foil, or any other planar separation with a printed board.
Dendritic Growth
Metallic filaments that grow between conductors in the presence of condensed
moisture and an electric bias.
Design-Rule Checking
The use of a computer-aided design program to perform continuity verification
of all conductor routing in accordance with appropriate design rules.
Desmear
The removal of friction-melted resin and drilling debris from a hole wall.
Dewetting
A condition that results when molten solder coats a surface and then recedes
to leave irregularly-shaped mounds of solder that are separated by areas
that are covered with a thin film of solder and with the basis metal not
exposed.
Diazo Material
A nonsilver, room-light hardening, ultraviolet-sensitive coating material.
Dielectric
A material with a high resistance to the flow of direct current, and which
is capable of being polarized by an electrical field.
Dielectric Constant
The ratio of the capacitance of a configuration of electrodes with a specific
material as the dielectric between them to the capacitance of the same
electrode configuration with a vacuum or air as the dielectric.
Dielectric Strength
The maximum voltage that a dielectric can withstand under specified conditions
without resulting in a voltage breakdown, usually expressed as volts per
unit dimension.
Digitizing (CAD)
The converting of feature locations on a flat plane to its digital representation
in X-Y coordinates.
Dimensional Stability
A measure of the dimensional change of material that is caused by factors
such as temperature changes, humidity changes, chemical treatment (aging),
and stress exposure.
Dimensioned Hole
A hole in a printed board whose location is determined by physical dimensions
or coordinate values that do not necessarily coincide with the stated
grid.
Dual-Strip Line
A stripline signal conductor embedded between two ground planes or between
two ground conductors on the same plane and is not necessarily centered
between the ground references.
Electrodeposited Foil
A metal foil that is produced by electro deposition of the metal onto
a material acting as a cathode.
Electro deposition
The deposition of a conductive material from a plating solution by the
application of electrical current.
Electroless Deposition
The deposition of conductive material from an autocatalytic plating solution
without the application of electrical current.
Elongation
The increase in length of a material that is caused by a tensile load.
Engineering Drawing
A document that discloses the physical and functional end-product requirements
of an item by means of pictorial and/or textual presentations.
Epoxy Glass Substrate
A two-part epoxy resin that polymerizes spontaneously when the two components
are mixed, combined with glass fiber to form a substrate
Etch Factor
The ratio of the depth of etch to the amount of lateral etch, i.e., the
ratio of conductor thickness to the amount of undercut.
Etchant
A solution used to remove the unwanted portion of material from a printed
board by a chemical reaction.
Etchback
The controlled removal by a chemical or gaseous process, to a specific
depth, of nonmetallic materials from the sidewalls of holes in order to
remove resin smear and to expose additional internal conductor surfaces.
Etching
The chemical, or chemical and electrolytic, removal of unwanted portions
of conductive or resistive material.
Fiducial Mark
A printed board artwork feature (or features) that is created in the same
process as the conductive pattern and that provides a common measurable
point for component mounting with respect to a land pattern or land patterns.
First Article
A part or assembly that has been manufactured prior to the start of a
production run for the purpose of ascertaining whether or not the manufacturing
processes used to fabricate it are capable of making items that will meet
all applicable end-product requirements.
Flexible Double-Sided Printed Board
Double-sided printed board, either printed circuit or printed wiring,
using a flexible base material only.
Flexible Multilayer Printed Board
Multilayer printed board, either printed circuit or printed wiring, using
flexible base materials only. Different areas of the flexible multilayer
printed board may have different number of layers and thicknesses.
Flexible Printed Board
A printed board using a flexible base material only. May be partially
provided with electrically non-functional stiffeners and/or cover lay.
Flexible Printed Circuit
A patterned arrangement of printed circuitry and components that utilizes
flexible base material with or without flexible cover lay.
Flexible Printed Wiring
A patterned arrangement of printed wiring that utilizes flexible base
material with or without flexible cover lay.
Flexible Single-Sided Printed Board
Single-sided printed board, either printed circuit or printed wiring,
using flexible base materials only.
Foil Lamination
A process for making multilayer printed boards with surface layer(s) of
metal foil bonded in a single operation.
Fully Additive Process
An additive process wherein the entire thickness of electrically- isolated
conductors is obtained by the use of electroless deposition.
Gel Time
The time in seconds required for prepreg to change its physical state
from that of a solid material to a liquid, and then back to a solid material.
Gerber Data
A type of data that consists of aperture selection and operation commands
and dimensions in X- and Y-coordinates. (The data is generally used to
direct a photo plotter in generating photo plotted artwork.)
Glass Transition Temperature
The temperature at which an amorphous polymer, or the amorphous regions
in a partially-crystalline polymer, changes from being in a hard and relatively-brittle
condition to being in a viscious or rubbery condition.
Ground
A common reference point for electrical circuit returns, shielding, or
heat sinking.
Ground Plane
A conductor layer or portion thereof, that serves as a common reference
for electrical circuit returns, shielding, or heat sinking.
Ground Plane Clearance
Removed portions of a ground plane that isolate it from a hole in the
base material to which the plane is attached.
Haloing
Mechanically-induced fracturing or delamination, on or below the surface
of a base material that is usually exhibited by a light area around holes
or other machined features.
Hand Soldering
Soldering using a soldering iron or other hand-held, operator- controllable
apparatus.
Heatsink
A mechanical device that is made of a high thermal-conductivity and low
specific-heat material that dissipates heat generated by a component or
assembly.
Hipot Test
A method in which the unit under test is subjected to a high alternating
current (ac) voltage.
Hole Breakout
A condition in which a hole is not completely surrounded by the land.
Hole Pattern
The arrangement of all the holes in a printed board or production board.
Hole Void
A void in the metallic deposit of a plated-through hole that exposes the
base material.
Hybrid Circuit
An insulating base material with various combinations of interconnected
film conductors, film components, semiconductor dice, passive components
and bonding wire that form an electronic circuit.
Immersion Plating
The chemical deposition of a thin metallic coating over certain basis
metals that is achieved by a partial displacement of the basis metal.
Impedance
The resistance to the flow of current, represented by an electrical network
of combined resistance, capacitance and inductance reaction, in a conductor
as seen by an AC source of varying time voltage. The unit of measure is
ohms.
Innerlayer Connection
A conductor that connects conductive patterns on internal layers of a
multilayer printed board, e.g. a plated-through hole.
Inspection Lot
A collection of units of product that are identified and treated as a
unique entity from which a sample is drawn and inspected in order to determine
conformance with acceptability criteria.
Insulation Resistance
The electrical resistance of an insulating material that is determined
under specific conditions between any pair of contacts, conductors, or
grounding devices in various combinations.
Interfacial Connection
A conductor that connects conductive patterns on both sides of a printed
board, e.g. a plated-through hole.
Internal Layer
A conductive pattern that is contained entirely within a multilayer printed
board.
Ionic Cleanliness
The degree of surface cleanliness with respect to the number of ions or
weight of ionic matter per unit square of surface.
Ionizable (Ionic) Contamination
A polar (ionic) compound, usually a processing residue that dissolves
in water as free ions. (This includes flux activators, finger prints,
etching or plating salts, etc., that decrease the resistivity of water
when they are dissolved in it.)
Laminate Thickness
The thickness of single- or double-sided metal-clad base material prior
to any subsequent processing.
Laminate Void
The absence of resin or adhesive in an area that normally contains them.
Land
A portion of a conductive pattern usually, but not exclusively, used for
the connection and/or attachment of components.
Land Pattern
A combination of lands that is used for the mounting, interconnection
and testing of a particular component.
Layer-to-Layer Registration
The degree of conformity of a conductive pattern, or portion thereof,
to that of any other conductor layer of a printed board.
Layer-to-Layer Spacing
The thickness of dielectric material between adjacent layers of conductive
patterns in a printed board.
Lifted Land
A land that has fully or partially separated (lifted) from the base material,
whether or not any resin is lifted with the land.
Magnification Power
The ratio of the tangent of one-half of the angle (beta) subtended by
the image of an object (H), as seen through and centered in the field
of view of the magnification device, to the tangent of one-half of the
angle (alpha) subtended by the object (H) as seen at 10 inches by the
unaided eye.
Manufacturing Drawing
A document that shows the dimensional limits or grid locations that are
applicable to any and all parts of a product to be fabricated, including
the arrangement of conductors and nonconductive patterns or elements;
the size, type, and location of holes; and all other necessary information.
Mass Lamination
The simultaneous lamination of a number of pre-etched, multiple-image,
C-staged resin panels or sheets that are sandwiched between layers of
B-staged resin and copper foil.
Master Drawing
A document that shows the dimensional limits or grid locations that are
applicable to any and all parts of a product to be fabricated, including
the arrangement of conductors and nonconductive patterns or elements;
the size, type, and location of holes; and all other necessary information.
Measling
A condition that occurs in laminated base material in which internal glass
fibers are separated from the resin at the weave intersection. (This condition
manifests itself in the form of discrete white spots or “crosses”
that are below the surface of the base material. It is usually related
to thermally-induced stress.)
Metal-Clad Base Material
Base material covered with conductive foil on one or both sides.
Metallization (n.)
A deposited or plated thin metallic film that is used for its protective
and/or electrical properties.
Micro sectioning
The preparation of a specimen of a material, or materials, that is to
be used in a metallographic examination. (This usually consists of cutting
out a cross-section, followed by encapsulation, polishing, etching, staining,
etc.)
Microstrip
A transmission-line configuration that consists of a conductor that is
positioned over and parallel to, a ground plane with a dielectric between
them.
Minimum Annular Width
The minimum width of metal(s) at the narrowest point between the edge
of a hole and the outer edge of a circumscribing land. (This determination
is made to the drilled hole on internal layers of multilayer printed boards
and to the edge of the plating on external layers of multilayer and double-sided
printed board.)
Mixed Technology
In surface mounting, refers to mixing through hole component and surface
mounting components on the same side of a printed circuit board.
Mounting Hole
A hole that is used for the mechanical support of a printed board or for
the mechanical attachment of components to a printed board.
Multilayer Printed Board
The general term for a printed board that consist of rigid or flexible
insulation materials and three or more alternate printed wiring and/or
printed circuit layers that have been bonded together and electrically
interconnected.
Multilayer Printed Circuit Board
A multilayer printed board with two or more printed circuit layers.
Multilayer Printed Circuit Board Assembly
An assembly that uses a multilayer printed circuit board for component
mounting and interconnecting purposes.
Multilayer Printed Wiring Board
A multilayer printed board with only printed wiring for its conductive
layers.
Multilayer Printed Wiring Board Assembly
An assembly that uses a multilayer printed wiring board for component
mounting and interconnecting purposes.
Nail Heading
The flared condition of copper on an inner conductive layer of a multilayer
printed board that is caused by hole-drilling.
Negative Etchback
Etchback in which the inner conductor layer material is recessed relative
to the surrounding base material.
Net
An entire string of electrical connections from the first source point
to the last target point, including lands and vias.
Net List
A list of alphanumeric representations, each of which is used to describe
a group of two or more points that are electrically common.
Outgassing
The gaseous emission from a laminate printed board or component when the
board or the printed board assembly is exposed to heat or reduced air
pressure, or both.
Panel
A rectangular sheet of base material or metal-clad material of predetermined
size that is used for the processing of one or more printed boards and,
when required, one or more test coupons.
Panel Drawing
A document that shows the production master with related manufacturing
patterns and artifacts that relate to the fabrication of printed boards.
Panel Plating
The plating of an entire surface of a panel including holes.
Pareto Analysis
A problem-solving technique whereby all potential problem areas or sources
of variation are ranked according to their contribution to the end result.
Partial (Bikini) Coverlay
This coverlay is typically used in the manufacture of Rigid-Flex boards
where the coverlay material is only in the flexible portion of the board.
This removes acrylic adhesive from the rigid portions of the board increasing
board reliability.
Peel Strength
The force per unit width that is required to peel a conductor foil from
a laminate perpendicular to the surface of the substrate.
Photo plotting
A photographic process whereby an image is generated by a controlled-
light beam that directly exposes a light-sensitive material.
Photo resist
A material that is sensitive to portions of the light spectrum and that,
when properly exposed can mask portions of a base metal with a high degree
of integrity.
Photo resist Image
An exposed and developed image in a coating on a base material.
Pinhole (Material)
An imperfection in the form of a small hole that penetrates entirely through
a layer of material.
Pinhole (Photo tool)
A clear defect that is completely within a black pattern or in the black
background of a clear pattern.
Pink Ring
A leached zone around a through-hole/inner-layer interface from which
a copper oxide coating has been chemically removed.
Pit
An imperfection in the form of a small hole that does not penetrate entirely
through a layer of foil.
Pitch
The nominal center-to-center distance of adjacent conductors. (When the
conductors are of equal size and their spacing is uniform, the pitch is
usually measured from the reference edge of the adjacent conductors.)
Plated-Through Hole (PTH)
A hole with plating on its walls that makes an electrical connection between
conductive patterns on internal layers, external layers, or both, of a
printed board.
Plating, Burned
A rough, dull electro deposit that was caused by excessive plating current
density.
Plating Up
The electrochemical deposition of a conductive material on a base material
that takes place after the base material has been made conductive.
Plating (n.)
The chemical or electrochemical deposited metal on a surface.
Plating (v.)
Chemical or electrochemical deposition of metal on all or part of the
conductive pattern, base material and/or through holes.
Post Curing
Heat aging in order to stabilize material through stress relieving.
Pouch Material
The protective barrier material used in the manufacture of Rigid-Flex
Boards. This material is typically removed from the flexible portion of
the board prior to shipment.
Prepreg
A sheet of material that has been impregnated with a resin cured to an
intermediate stage, i.e., B-staged resin.
Printed Circuit
A conductive pattern that is composed of printed components, printed wiring,
discrete wiring, or a combination thereof, that is formed in a predetermined
arrangement on a common base. (This is also a generic term that is used
to describe a printed board that is produced by any of a number of techniques.)
Printed Circuit Board
Printed board that provides both point-to-point connections and printed
components in a predetermined arrangement on a common base.
Printed Circuit Board Assembly
An assembly that uses a printed circuit board for component mounting and
interconnecting purposes.
Printed Wiring Board
A printed board that provides point-to-point connections but not printed
components in a predetermined arrangement on a common base.
Printed Wiring Board Assembly
An assembly that uses a printed wiring board for component mounting and
interconnecting purposes.
Production Board
A printed board or discrete-wiring board that has been manufactured in
accordance with the applicable detailed drawings, specifications, and
procurement requirements.
Production Master
A 1 to-1 scale pattern that is used to produce rigid or flexible printed
boards within the accuracy specified on the master drawing.
Production Panel (PP)
An arrangement of printed boards fabricated from laminate or base materials
as a group in a specific cluster to facilitate economic fabrication techniques
using controlled and documented chemical, mechanical and electrical processes.
Reflow Soldering
The joining of surfaces that have been tinned and/or have solder between
them, placing them together, heating them until the solder flows, and
allowing the surface and the solder to cool in the joined position.
Registration
The degree of conformity of the position of a pattern (or portion thereof),
a hole, or other feature to its intended position on a product.
Registration Mark
A stylized pattern (symbol) that is used as a reference point for registration.
Residue
Any visual or measurable form of process-related contamination.
Resin
A natural or synthetic resinous material. (See also “Rosin”
and “Synthetic Resin.”)
Resin Flux
A resin and small amounts of organic activators in an organic solvent.
Resin Recession
The presence of voids between the plating of a plated-through hole and
the wall of
the hole as seen in micro sections of plated-through holes that have been
exposed
to high temperatures.
Resin Smear
Base material resin that covers the exposed edge of conductive material
in the wall of a drilled hole. (This resin transfer is usually caused
by the drilling operation).
Resin-Rich Area
The location in a printed board of a significant thickness of unreinforced
surface-layer resin that is of the same composition as the resin within
the base material.
Resin-Starved Area
The location in a printed board that does not have a sufficient amount
resin to completely wet out the reinforcing material. (Evidence of this
condition is often in
the form of low-gloss dry spots or exposed fibers.)
Resist
A coating material that is used to mask or protect select areas of a pattern
during manufacturing or testing from the action of an etchant, plating,
solder, etc.
Rework
The act of reprocessing noncomplying articles, through the use of original
or alternate equivalent processing, in a manner that assures compliance
of the article with applicable drawings or specifications.
Rigid Double-sided Printed Board
Double-sided printed board, either printed circuit or printed wiring,
using rigid base materials only.
Rigid Multilayer Printed Board
Multilayer printed board, either printed circuit or printed wiring, using
rigid base materials only.
Rigid Printed Board
A printed board using rigid base materials only.
Rigid Single-sided Printed Board
Single-sided printed board, either printed circuit or printed wiring,
using rigid base materials only.
Rigid-flex Double-sided Printed Board
Double-sided printed board, either printed circuit or printed wiring,
using combinations of rigid and flexible base materials.
Rigid-Flex Printed Board
A printed board with both rigid and flexible base materials.
Runout
The sum of the cumulative-pitch error across a number of functional patterns
on a step-and-repeat photo tool.
Sequentially-Laminated Multilayer Printed Board
A multilayer printed board that is formed by laminating together through-hole
plated double-sided or multilayer boards. (Thus, some of its conductive
layers are interconnected with blind or buried vias.)
Shadowing, Etchback
A condition that occurs during an etchback process in which the dielectric
material immediately next to the foil is not removed completely. (This
can occur even though an acceptable amount of etchback may have been achieved
elsewhere.)
Shear Strength
The force required to shear apart adhesive-bonded (and cured) materials
and/or components.
Short, Electrical (n.)
A fault that causes to be connected two or more points that are normally
electrically separated.
Signal Conductor
An individual conductor that is used to transmit an impressed electrical
signal.
Single-Sided Printed Board
A printed board with a conductive pattern on only one side.
Solder
A metal alloy with a melting temperature that is below 427-deg.C (800-deg.F).
Solder Ball
A small sphere of solder adhering to a laminate, resist, or conductor
surface. (This generally occurs after wave solder or reflow soldering.)
Solder Bath
A container or vessel of molten solder into which component parts or assemblies
are immersed.
Solder Bridging
The unwanted formation of a conductive path of solder between conductors.
Solder Bump
A round ball of solder used to make interconnections between a flip-chip
component and a base material during controlled-collapse soldering.
Solder Coat
A layer of solder that is applied directly from a molten solder bath to
a conductive pattern.
Solder Fillet
A normally concave surface of solder that is at the intersection of the
metal surfaces of a solder connection.
Solder Leveling
A solder coating process that causes redistribution and/or partial removal
of excess molted solder from a printed board by applying sufficient heat
and mechanical force.
Solder Paste Flux
Solder paste without the solder particles.
Solder Plug
A core of solder in a plated-through hole.
Solder Resist
A heat-resisting coating material applied to selected areas to prevent
the deposition of solder upon those areas during subsequent soldering.
Solder Side
The secondary side of a single-sided assembly.
Solder Wicking
The capillary movement of solder between metal surfaces, such as strands
of wire.
Solderability
The ability of a metal to be wetted by molten solder.
Stable Process
A process that is in statistical control.
Statistical Control
The condition of describing a process from which all special causes of
variation have been eliminated and, thereby, only common causes remain.
Statistical Process Control (SPC)
The use of statistical techniques to analyze a process or its output so
as to be able to take appropriate action in order to achieve and maintain
a state of statistical control and to improve process capability.
Step-and-Repeat
The successive exposure of a single image in order to produce a multiple-image
production master.
Strain Relief (Connector)
A receptacle connector device that prevents the disturbance of the contact
and cable terminations.
Stress Relief
The portion of a component lead or wire lead that is formed in such a
way as to minimize mechanical stresses after the lead is terminated.
Stripline
A transmission-line configuration that consists of a conductor that is
positioned equidistant between, and parallel to, ground planes with a
dielectric among them.
Surface-Mount Component (SMC)
A leaded or leadless device (part) that is capable of being attached to
a printed board by surface mounting.
Test Coupon
A portion of quality conformance test circuitry that is used for a specific
test, or group of related tests, in order to determine the acceptability
of a product.
Tetrafunctional Resins
Materials that have four reactive groups per molecule.
Thermal Conductivity
The property of a material that describes the rate at which heat will
be conducted through a unit area of the material for a given driving force.
Thermal Expansion Mismatch
The absolute difference between the thermal expansion of two components
or materials.
Thermal Relief
The crosshatching of a ground or voltage plane that minimizes blistering
or warping during soldering operations.
Thermal Zone
A metal-integrity evaluation zone that extends a specified distance beyond
the ends of the lands in a micro section of a vertical portion of a plated-through
hole. (Unless otherwise specified, the- extended distance is 0.08 mm (0.003-inch).
Thermoset
A plastic that undergoes a chemical reaction when exposed to elevated
temperatures that leads to it having a relatively infusible or cross linked
stated that cannot be softened or reshaped by subsequent heating.
Thick Film
A film, greater than 0.1 mm (0.004-inch) thick, deposited by screen printing
and subsequently fired at high temperatures in order to fuse it into its
final functional form.
Thick-Film Circuit
A microcircuit in which passive components of a ceramic-metal composition
are formed on base material by screening and firing.
Tinning
The application of molten solder to a basis metal in order to increase
its solderability.
Tolerance
The total amount by which a specific dimension is permitted to vary.
Toleranced Dimension
A dimension with a tolerance.
Tooling Feature
A physical feature that is used exclusively to position a printed board
or panel during a fabrication, assembly or testing process.
Tooling Hole
A tooling feature in the form of a hole in a printed board or fabrication
panel.
Touch-Up
The identification and elimination of defects in a product.
Ultrasonic Cleaning
Immersion cleaning that is done by passing high-frequency sound waves
through a cleaning medium to cause micro agitation.
Unsupported Hole
A hole in a printed board that does not contain plating or other type
of conductive reinforcement.
Via
A plated-through hole that is used as an interlayer connection, but in
which there is no intention to insert a component lead or other reinforcing
material. (See also “Blind Via” and “Buried Via”.)
Weave Exposure
A base material surface condition in which unbroken fibers of woven glass
cloth are not completely covered by resin.
Wrinkles
Ridges, creases or furrows in a coating or resist that are formed after
the material has adhered to a metal, such as solder, that subsequently
melts and resolidifies.
Wrought Foil
A metal foil that is formed by the rolling of cast metal.
X Axis
The horizontal or left-to-right direction in a two-dimensional system
of coordinates. (This axis is perpendicular to the Y axis.)
Y Axis
The vertical or bottom-to-top direction in a two-dimensional system of
coordinates.
Z Axis
The Axis perpendicular to the plane formed by the X and Y datum reference.
This axis usually represents the thickness of the boards.
Marc Strickland
Process Engineer Manager
Lenthor Engineering LLC
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