Semiconductor Assembly Glossary

Semiconductor Packaging Glossary

alloy - a substance that exhibits metallic properties and is composed of two or more chemical elements, at least one of which is a metal

alloy42 - an alloy composed of about 57.7% Fe, 41% Ni, 0.8% Mn, and 0.5% Co

anode - 1. the electrode where oxidation takes place; 2. in lead finish, the source material for the metal plating

array - a set of elements (usually referring to leads or balls in the context of semiconductor assembly) arranged in rows and columns

assembly - the process of putting a semiconductor device or integrated circuit in a package of one form or another; it usually consists of a series of packaging steps that include: die preparation, die attach, wirebonding, encapsulation or sealing, deflash, lead trimming/forming, and lead finish

back-end - refers collectively to later assembly process steps from molding to all steps succeeding it; also known as 'end-of-line'

backgrinding - the process of grinding the back side of a wafer until the wafer attains the desired thickness

ball bond - a bond that looks like a ball, having originated from a molten sphere at the end of the bond wire

ball grid array (BGA) - a surface-mount package that utilizes an array of metal spheres or balls as the means of providing external electrical interconnection, as opposed to the pin-grid array (PGA) which uses an array of leads for that purpose

ball lifting - a failure mechanism wherein a ball bond either becomes detached from its bonding site or fails to attach to it

ball shear test (BST) - a process for testing the shear strength of a ball bond's adhesion to the bond pad that employs a needle to push the ball bond horizontally (parallel to the plane of the bond pad)

base - the lower half of a ceramic dual-in-line package

bonding diagram - a diagram showing how a device is to be wire-bonded

brightener - an electroplating additive that promotes the formation of fine crystal deposits that make the lead finish look brighter

brittle fracture - a type of fracture that exhibits minimal or no amount of plastic deformation prior to the rupture; usually induced by 'fast-acting' forces such as impact stresses

cap - 1. the upper half of a ceramic dual-in-line package; 2. the cover of a metal can or header package

capillary - a tool employed by the wirebonding machine to form ball bonds

cathode - 1. the electrode where reduction takes place; 2. the material to be plated, i.e., in lead finish, the leads of the package are the cathode

cavity - 1. the open space inside a hermetic package; 2. the recession in a mold chase that holds the leadframes for molding

CBGA - acronym for 'Ceramic Ball Grid Array'

ceramic - an organic, non-metallic material processed and used at high temperatures

cerdip - ceramic dual-in-line package; a hermetic package consisting of leads sandwiched by a ceramic base and a ceramic cap sealed together by glass

chip-on-lead (COL) - a packaging technology wherein the die is mounted directly on the leadframe

chip-out - a failure attribute wherein a small piece or block of the die (or package) breaks off from the die (or package)

chip-scale package (CSP) - any package whose dimensions do not exceed the die's dimensions by 20%

coefficient of thermal expansion (CTE) - the fractional change in dimensions of a material per unit change in its temperature; usually expressed in parts per million per deg C; also known as 'thermal coefficient of expansion' (TCE)

collet - a tool for picking up die for die attach

combo lid - a piece of metal that covers certain types of ceramic packages by being soldered onto the seal ring of the package

corrosion - electrochemical degradation of metals

cratering - a failure mechanism wherein the silicon under a bond pad becomes fractured and, in extreme cases, experiences displacement that leaves a crater behind

CSAM - C-Mode Scanning Acoustic Microscopy; an acoustic microscopy mode wherein the scanning is done across a horizontal (X-Y) plane of the sample at a given depth (Z); CSAM is useful for inspecting delaminations between layers

CTE - 'see Coefficient of Thermal Expansion'

curing - a heat treatment step to promote molecular cross-linking in an adhesive or molding compound to harden it into its final form

cycle time - the duration from the start of one cycle to the start of the next

defect - a physical or chemical imperfection; a characteristic that does not meet required specifications

defective - a manufactured product that has one or more defects

defect level - the proportion of electrical rejects inadvertently shipped to customers due to the inherent imperfection of any testing or inspection process; see also "dpm"

deflash - an assembly process step that removes flashes from a package; see DTFS

degradation - an unwanted change in a package or product

delamination - an unwanted partial or complete loss of adhesion or separation between two layers or features; a term usually employed to refer to loss of adhesion between the plastic molding compound of the package and the leadframe or die

design rules - a set of rules (usually dimensional and lay-out rules) that governs how an integrated circuit must be fabricated (wafer fab design rules) or assembled (assembly design rules)

destructive physical analysis (DPA) - a series of destructive steps performed on test rejects to check for any physical damage or defects on the package or die

devitrifying glass - glass that crystallizes upon cooling making them unreworkable

die - 1. a single chip from the wafer; 2. a small block of semiconductor material containing the device circuit

die attach - the assembly process step wherein the die is mounted on the support structure of the package, e.g., the leadframe die pad, cavity, or substrate

die lifting - the detachment of the die from its mounting

die overcoat - the assembly process step wherein the die is covered completely or selectively with a silicone layer to protect it from package stress and moisture

die pad - the part of a leadframe or package substrate where the die is mounted

die preparation - the assembly process step wherein each die is singulated from the wafer in preparation for die attach

die shear test (DST) - a process for testing the shear strength of the die's adhesion to the die pad that employs an indenting tool that pushes the die horizontally (parallel to the plane of the die pad)

DIP - acronym for 'Dual-in-Line Package'; a through-hole rectangular package consisting of two parallel sets of leads arranged along its two sides

DFP - acronym for 'Dual Flat Pack'

DOE - acronym for 'Design of Experiments'; a process for systematically designing a factorial experiment usually aimed at optimizing a process by varying its critical process inputs and determining which combination of input settings or values will give the most desired process output response

DPA -see 'Destructive Physical Analysis'

dpm - 1. acronym for 'defective parts per million' or the defect level expressed as the number of defective parts per million units produced; 2. acronym for 'defects per million' or the defect level expressed as the number of defects observed per million units produced

DTFS - acronym for 'Deflash; Trim; Form; Singulate'

ductile fracture - a type of fracture characterized by a considerable amount of plastic deformation prior to the rupture; usually induced by 'slow-acting' forces such as thermal stresses

EDX Analysis - stands for 'Energy Dispersive X-ray Analysis'; a SEM-based technique for identifying elements present on a sample often used in semiconductor manufacturing for distinguishing contaminants; also known as EDAX or EDS Analysis

electrochemical potential - the voltage needed for electroplating to proceed

electroplating - the process of depositing a metal coat or layer by passing current through a conductive medium

encapsulation - see 'molding'

end-of-line (EOL) - see 'back-end'

epoxy - a low-temperature cure, high-strength adhesive; used extensively as die attach material

eutectic alloy - the alloy with the lowest possible melting point that can be formed from a given combination of metals

eutectic die attach - a die attach process that uses a eutectic alloy as die attach material

eutectic temperature - the temperature at which a eutectic alloy solidifies or melts

failure -the inability of a product to meet any of its specifications, whether electrical or visual-mechanical

fatigue failure - failure due to the application of repeating or cyclical loads or stresses

FCOL - acronym for 'Flip Chip on Lead'; a flip chip package wherein the die is mounted directly on the leadframe

fillers - inert materials usually included in molding compounds; fillers do not change chemically during mold curing but affects the molding compound's properties such as flexibility and thermal expansion

fine leak (FL) test - a hermeticity test done to check for the presence of very minute leakage paths in a hermetic package

first bond - the bond formed on the die or the first bond formed during a wirebonding cycle

flashes - excess molding compound at the parting of the package due to improper mold set-up or worn-out molds

flux - 1. a material used to promote fusions or joining of metals during soldering, welding, or smelting; 2. in soldering, a material used to break down the oxides on a metal surface

FMEA - acronym for 'Failure Mode and Effects Analysis'; a methodology for identifying the potential failure modes that a product or process may encounter and addressing them based on a priority ranking determined by the risks they pose

forming - the process of bending the leads into their final shape; see DTFS

fracture - to break or to crack

fractography - a scientific and systematic analysis of the fracture surface to determine where the fracture originated and how it propagated

front-end - refers collectively to early assembly process steps, i.e., assembly steps prior to molding; also known as 'front-of-line'

front-of-line (FOL) - see 'front-end'

FTIR Analysis - stands for 'Fourier Transform Infrared Analysis'; a technique for identifying contaminants through the analysis of the sample's transmittance and reflectance of infrared rays at different frequencies

glass - a supercooled liquid that exhibits tremendous viscosity if cooled below its glass transition temperature; solder glass is commonly used as a sealing material for certain ceramic packages

glass transition temperature (Tg) - the temperature beyond which a polymer loses its glass properties and acquires elastomeric (rubber-like) properties

go/no-go test - a test that simply indicates whether the product passes or fails

grain boundary - interface between two crystal regions that differ in the orientation of their atomic arrangements

gross leak (GL) test - a hermeticity test done to check for the presence of large leakage paths in a hermetic package

hermeticity test - a test done to determine how air-tight a hermetically-sealed package is; see also 'fine leak test' and 'gross leak test'

histogram - a frequency plot of data from a normal distribution often used in analyzing the performance of a given process

HTS - acronym for 'High Temperature Storage'; a reliability test that subjects samples to a high temperature (usually 150 deg C) environment over a specified period of time (usually 168 H)

IMC - acronym for 'Intermetallic Coverage' or 'Intermetallic Compound"

incomplete fill - a failure attribute wherein a certain part of the package was not covered by a sufficient amount of molding compound

intermetallic compound - a compound formed between two metals in intimate contact with each other; this phrase is often applied to compounds formed between the bond pad and the wirebond during wirebonding

intermetallic coverage - the area on the bond pad covered with intermetallic compounds

interposer - an intermediate layer or structure that provides electrical connection between the die and the package

invalid reject - an acceptable product that has been erroneously identified as unacceptable

IPC - acronym for 'Institute for Interconnecting and Packaging Electronic Circuits'; an electronic packaging organization that has already been renamed to: 'Association Connecting Electronic Industries'

JLCC - acronym for 'J-Leaded Chip Carrier'; a ceramic surface-mount package with J-shaped leads along its four sides

KGD - acronym for 'Known Good Die'; an unpackaged semiconductor chip known to meet all of its electrical specifications

kovar - an alloy composed of about 53.48% Fe, 29% Ni, 17% Co, 0.2% Si, 0.3% Mn, and 0.02%C

laminate - 1. a layer; 2. a sheet of plastic or other material with metal traces on one or both sides used as raw material for printed circuits

LCC - acronym for 'Leadless Chip Carrier'; a surface-mount package with no protruding leads; it instead has exposed metal pads for external interconnection

lead finish - the assembly process step wherein the external leads of the package are covered with another metal for protection and better conductivity, solderability, and appearance

lead forming - the assembly process step wherein the external leads of the package are mechanically formed into their final shape

leadframe - a metal frame structure used as skeleton support for many package types

lead-free - a process, such as lead finish, that doesn't use the element lead (Pb)

lead trimming - the assembly process step wherein all the leads of the package are cut and isolated from the lead frame

leveller - an electroplating additive used to ensure smooth deposits that are free of dendrites

LFCSP - acronym for 'Leadframe Chip Scale Package'; a CSP that employs a leadframe for its support

lifted ball - a ball bond that failed to attach properly to the die or lead finger

loop profile - the path formed by a bond wire from one bond to the other

loop height - the height of the loop formed by a bond wire

lot - a group of similarly-processed semiconductor devices, usually from the same production run, treated as a homogeneous population

lot acceptance test (LAT) - a test or series of tests to determine whether a lot is shippable to the customer or not

LQFP - acronym for 'Low Profile Quad Flat Pack'; a thin plastic surface-mount package with leads along its four sides

manufacturing validation - a series of assembly runs to verify that a newly-released assembly process is meeting expected process outputs

material review board (MRB) - a team that oversees the handling or dispositioning of abnormally processed or low-yielding lots

MCM - see 'Multi-Chip Module'

MCM-C - acronym for 'Multi-Chip Module-Ceramic'

MCM-L - acronym for 'Multi-Chip Module-Laminate'

micron - a unit of measurement equal to one millionth of a meter; also referred to as a micrometer

mil - a unit of measurement equal to 1/1000 or 0.001 of an inch; 1 mil =25.4 microns

molding - the assembly process step wherein the devices are encapsulated in plastic; also referred to as 'encapsulation'

molding compound - plastic material used for encapsulating IC's

multi-chip module (MCM) - a package containing more than a single chip inside

MQFP - acronym for 'Metal Quad Flat Pack'

MSL - acronym for 'Moisture Sensitivity Level'; a number denoting the degree of vulnerability of a package to cracking caused by internal moisture vaporization during reflow or board mounting

MSOP - acronym for 'Micro Small Outline Package'

NDBP - acronym for 'Non-Destructive Bond Pull'

OCAP - acronym for 'Out-of-Control Plan'; a flow chart or a documented set of procedures defining the actions required if a process gets out of control

package - a structure that serves as a container or form of cover for the die to provide it with protection, a means of external electrical connection, and if necessary, a means of identification

PDIP - acronym for 'Plastic Dual-in-Line Package'; see 'DIP'

PIND - acronym for 'Particle Impact Noise Detection'; a technique for detecting any loose particles inside a hermetic package

pin grid array (PGA) - a surface-mount package that utilizes an array of metal pins as the means of providing external electrical interconnection, as opposed to the ball grid array (BGA) which uses an array of balls for that purpose

pitch - the center-to-center distance between adjacent leads on a semiconductor package

PLCC - acronym for 'Plastic Leaded Chip Carrier'; a plastic surface-mount package with leads all around its periphery

polyimide - a high-temperature polymer that requires multi-step curing

polymer - a material that consists of long chains of similar molecular combinations of carbon, oxygen, hydrogen, nitrogen, etc.

popcorn cracking - package cracking caused by the sudden vaporization of the internal moisture of the package during reflow or board mounting

preform - a small and thin piece of metal used as raw material for eutectic die attach

PQFP - acronym for 'Plastic Quad Flat Pack'

PSOP - acronym for 'Power Small Outline Package'; basically an SOIC package with a heat slug to enhance its power dissipation capability

Quad Flat Pack (QFP) - a rectangular package that has leads on all its sides

QSOP - acronym for 'Quarter-size Small Outline Package'

reflow - 1) the process of remelting the solder on the leads of devices by subjecting them to a high enough temperature; 2) the process of soldering surface-mount devices on a board by passing the board through a reflow oven

residual gas analysis (RGA) - a technique for determining the moisture or gas content of the cavity of a hermetic package

runners - canals in the mold where liquid molding compound travels to reach the parts for molding

scanning acoustic microscopy (SAM) - a technique that employs ultrasonic waves to analyze disjoints or delaminations within a package

scanning electron microscopy (SEM) - a microscopy technique that achieves high resolution and excellent depth of field by employing electrons instead of light for its imaging processes

SDIP - acronym for 'Shrink Dual-in-Line Package'

seal glass - glass material that's used to seal certain ceramic packages such as cerdips

second bond - the bond formed on the package or the second bond formed during a wirebonding cycle

side-brazed package - a type of ceramic dual-in-line package wherein the leads are brazed to the sides of the package

solder heat resistance test (SHRT) - a reliability test that determines the ability of a package to withstand extreme board-mounting or board-soldering conditions

singulation - the assembly process step wherein the packages are finally separated from the lead frame strip ; see DTFS

SIP - 1. acronym for 'Single-in-Line Package' - a through-hole package whose leads are aligned in just a single row; 2. acronym for 'System-in-a-Package' - a package that contains several chips and components that comprise a completely functional stand-alone electronic system

SJR - acronym for 'solder joint reliability'

SMD - acronym for 'Surface-Mount Device'

SMT - acronym for 'Surface-Mount Technology'

SOIC - acronym for 'Small Outline Integrated Circuit'; a plastic surface-mount package with leads on its two long sides only

SOJ - acronym for 'J-Leaded Small Outline Package'

solder - a metal alloy (usually composed of lead and tin) used in bonding metals together

solderability testing (ST) - a testing process that determines whether the leads of a package exhibits acceptable wetting, i.e., adequate ability to be soldered onto boards

solder mask - an insulative pattern applied on a surface that exposes only the areas that need to be soldered

SOT - acronym for 'Small Outline Transistor'

SSOP - acronym for 'Shrink Small Outline Package'

SPC - 'Statistical Process Control'; a program for keeping a process stable by using statistical concepts in the monitoring and adjustment of the process

substrate - 1. the base material of the support structure of an IC; 2. the surface where the die or other components are mounted during packaging; 3. the semiconductor block upon which the integrated circuit is built

surface-mount - a phrase used to denote that a package is mounted directly on the top surface of the board, as opposed to 'through-hole', which refers to a package whose leads need to go through holes in the board in order to get them soldered on the other side of the board

tape and reel - a process wherein surface-mount devices are packed inside a tape with packets after which the tape is wound around a reel to facilitate transport of the devices

thermocouple - a temperature sensor formed by the junction of two dissimilar metals which has a voltage output proportional to the difference in temperature between the hot junction and the lead wire (cold) junction

thermostat - a device or circuit that indicates whether a measured temperature is above or below a particular temperature threshold or trip point

through-hole - a phrase used to refer to a package whose leads need to go through holes in the board in order to get them soldered on the other side of the board, as opposed to 'surface mount', which refers to a package that is mounted directly on the top surface of the board

throughput rate - the maximum repetitive rate at which a data converter can operate within a specified accuracy

throwing power - the ability of an electroplating bath to produce a uniform deposit

TO - acronym for 'transistor outline'

technical review board (TRB) - a team that oversees process or product changes to ensure that such changes will not result in any technical problems

TFP - acronym for 'Triple Flat Pack'

THB - acronym for 'Temperature Humidity Bias'; a reliability test used in accelerating corrosion

thermoplastics - a type of polymer that can be reheated and cooled repeatedly without degradation (as long as the temperatures used are below the decomposition temperature) allowing it to be recycled

thermosets - a type of polymer that can not be recycled since it can only be heated once into a hard resin, which has a cross-linked molecular structure

tolerance - the amount of deviation that a device's output parameter is allowed to exhibit from its nominal or target value

TQFP - acronym for 'Thin Quad Flat Pack'

trim - the process of isolating the leads of a leadframe from each other; see DTFS

TSOP - acronym for 'Thin Small Outline Package'

TSSOP - acronym for 'Thin Shrink Small Outline Package'

UBM - acronym for 'Under Bump Metallurgy'; the layer of metal or alloy deposited over each bond pad (so as to be under each bump or ball) of a bumped die

underfill - an encapsulating material deposited in the gap between a die or package and its substrate to minimize the CTE between them and improve their solder joint reliability

vitreous glass - glass that is non-crystallizing, making it reworkable without degradation

void - an absence of material, often used to refer to such imperfections located inside the die attach material or the molding compound

VSOP - acronym for 'Very Small Outline Package'

W-CSP - acronym for 'Wafer-level Chip-Scale Package'; a true-chip-size packaging technology wherein the packaging steps are performed at wafer level

wafer - a thin, polished slice of monolithic semiconductor on which an array of die circuits are fabricated

wafer grinding - see 'backgrinding'

wafer saw - the assembly process or step wherein the wafer is sawn into individual die

wedge - a tool employed by the wirebonding machine to form wedge bonds

wedge bond - a flat-looking bond formed by a wedge bonding tool

wirebonding - an assembly process or step that connects wires between the die and the bonding sites of the package (e.g., the lead fingers of the leadframe or the bonding posts of the package)

wire pull test - a process for testing the strength of a bond's adhesion to its bonding site involving a hook that exerts an upward pull on the wire of the bond being tested

wire sweeping - a phenomenon wherein the flow of the molding compound during molding sways the bond wires in its direction

yield - the proportion of good devices in a lot or run

See Also: Assembly; Assembly Equipment

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