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:  AssemblyAssembly Equipment

 

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