SEMATECH Dictionary of Semiconductor Terms

A-Am | An-Az | B | C-Ch | Ci-Com | Con-Cz | D-De | Df-Dz | E-En | Eo-Ez | F-Fl
Fm-Fz | G | H | I | J-K | L | M-Mes | Met-Mz | N | O | P-Ph | Pi-Pq | Pr-Pz | Q | R
S-Se | Sh-So | Sp-Sta | Ste-Sz | T-Th | Ti-Tz | U-V | W-Z

"A - AM"

abrasive n		a granular compound used for grinding or cutting. [SEMATECH]
abrasive characteristics n		of package molding compounds, the mold roughening or wearing characteristics of a plastic molding compound used to encapsulate electronic devices. These characteristics are the result of the fillers, such as silica, that are added to the plastic in order to control the molding and molded characteristics of the material. [SEMI G31-86]
absolute pressure n		in mass flow controllers, the pressure measured relative to zero pressure (perfect vacuum). [SEMI E28-92]
absorb v		the taking up of a liquid or gas into the bulk of another material. [SEMATECH]
abstract class n		a class with no instances that is created only for the purpose of organizing a class hierarchy or defining methods and variables that will apply to lower-level classes. The term "virtual class" refers to the same concept. [SEMATECH]
abstract data type n		a data type that is defined by a programmer and not built into the programming language. Abstract data types are typically used to create high-level structures that correspond to the real-world objects represented in a program. [SEMATECH]
accelerometer n		a sensor that measures acceleration or gravitational force. [SEMATECH]
acceptable quality level (AQL) n		generally, 95% confidence that material of the stated AQL will pass sample inspection. This is distinct from reliability, which measures failures over an extended period of time. [1994 National Technology Roadmap for Semiconductors]
acceptance criteria n		the criteria that a system or component must satisfy to be accepted by a user or customer. (Copyright 1993 IEEE. All rights reserved.)
acceptance testing n		testing performed on a product or equipment to determine whether an individual lot of the product or equipment conforms with specified requirements. [Adapted from ASTM F412-94]
acceptor n		in a semiconductor, an impurity in a semiconductor that accepts electrons excited from the valence band, leading to hole conduction. [SEMI M1-94 and ASTM F1241]
ACCESS n		an engineering data analysis system that compiles a database of wafer fabrication facility (fab) system, control, production, and structural data for yield analysis, manufacturing analysis, and production indices. Abbreviation for analysis computer for component engineering service support. [SEMATECH]
access time n		a time interval that is characteristic of a storage device and is essentially a measure of the time required to communicate with that device. (Copyright 1993 IEEE. All rights reserved.)
accumulation condition n		the region of the capacitance-voltage (C-V) curve for which a 5-V increment toward a more negative voltage for p-type material, or toward a more positive voltage for n-type material, results in a change of less than 1% in the maximum capacitance, C_max. [ASTM F1241] (The "max" part of the abbreviation "Cmax"is written with subscript lowercase letters.)
accuracy n		in statistical process control, the compliance of the measured or observed value to the true value or accepted reference value. [EIA 557]
acetic acid (CH₃COOH) n		a sour, colorless, liquid compound that is a component of vinegar. [SEMATECH]
acetone ([CH₃]₂CO) n		a colorless, volatile, and extremely flammable liquid used as a solvent and as a reagent. [SEMATECH]
AC fine test dust n		a graded, naturally occurring dust frequently used as a polydisperse test aerosol. It is composed of 68% SiO2, 16% Al2O3, and 4.6% Fe2O3. The fine grade has 39% of its mass in particles less than 5 micrometers in size and 73% in particles less than 20 micrometers in size. [SEMATECH]
acid n		1 : a substance that dissociates in water to liberate hydrogen or hydronium ions, donates a proton, accepts an unshared pair of electrons, or reacts with a base to form a salt. An acid has a pH of less than 7 and turns litmus paper red. [SEMATECH] 2 : a corrosive material with the chemical reaction characteristic of an electron acceptor. [SEMI S4-92]
acidosis n		an abnormal increase in hydrogen-ion concentration in the body caused by an accumulation of an acid or loss of a base; may be respiratory, metabolic, or renal in nature. [SEMATECH]
acid tank n		a chemically inactive receptacle containing acid for etching, cleaning, or stripping wafers. [SEMATECH]
ACK n		in message transfer, "Correct Reception" handshake code. NOTE-The name (derived from ACKnowledged) of one of the four standard handshake codes used in block transfer protocol. The code ACK (00000110) corresponds to the ASCII code that has the same pattern. [SEMI E4-87]
across-the-seat test n		a test for leakage across the internal seal of a test component (for example, from one side of the valve seat to the other). [SEMATECH]
active area n		the region of thin oxide on a die or wafer in which transistors and other circuits reside. [SEMATECH]
active devices n		semiconductor devices that have active function, such as integrated circuits and transistors. [SEMI G35-87] Contrast passive devices.
active equipment n		equipment that loads a cassette onto the cassette stage of another piece of equipment, or unloads a cassette from the cassette stage of another piece of equipment. [SEMI E23-91] Contrast passive equipment.
active minienvironment n		a minienvironment that creates and maintains a controlled condition. [SEMI E44-95]
active transfer partner n		in automated material movement, a transfer partner that physically participates in the micro-level portion of a transfer, either by moving the transfer object or by moving impediments within the transfer envelope, such as doors or clamps. NOTE-This term refers to the micro-level transfer phase only, and not to any setup activities prior to the transfer. For example, a port door may be opened during setup phase by passive partner. [Adapted from SEMI E32-94] Contrast with passive transfer partner.
actual equipment production n		actual number of product wafers processed during productive time (including equipment loading and unloading). [SEMATECH]
actual flow n		in mass flow devices, the gas flow as measured by an external standard, not the electrical output of a mass flow meter. [SEMI E27-92]
actuation cycle n		the full operation of a valve, such as from a fully opened position to fully closed and back to fully opened. [SEMATECH]
acute health effect n		a severe, usually critical, and often dangerous adverse effect on a human or animal body, with severe symptoms that rapidly change and exposure of short duration. [SEMATECH]
acute toxicity n		the acute adverse effects resulting from brief exposure to a material. [SEMATECH]
adhesion, resist edge n		the ability of the edge of an image in a developed resist coating to adhere to its substrate under applied physical or chemical stress. [ASTM F127-84]
adhesive stringer n		on a photolithographic pellicle, any detectable protrusion from the edge of the adhesive. [SEMI P5-94]
adjacent character misalignment n		in the serial alphanumeric marking of silicon wafers, the vertical distance (R) between the character baselines of two adjacent characters on the same line. [SEMI M12-92] (Also called character misalignment in SEMI M13-88.) Also see line spacing misalignment.
adjusted decibel (dBa) n		a unit used to express the relationship between the interfering effect of a noise frequency and a noise power level. [SEMATECH]
aeolotropic		see anisotropic.
AES		see Auger electron spectroscopy.
AFM		see atomic force microscopy.
aggregation object n		in equipment communications, an object that is composed (made up) of other objects. An aggregation may lose some degree of integrity if one of its components is missing. [SEMI E39-94] Also see component object.
air atmosphere n		a term used to indicate that, for a certain process or test, no specific ambient atmosphere is required. The process or test is usually carried out at atmospheric pressure, and the ambient air may be recirculated through the equipment. The relative humidity of the air and the room temperature may be specified. [SEMATECH]
air flow interruption n		disruption of airflow that causes particles to travel in a manner that may potentially contaminate the product or process fluids. [SEMATECH]
air velocity (VA) n		in the thermal testing of semiconductor devices, the velocity of the cooling air at a specified location upstream from the device under test. Air velocity is measured in linear feet per minute. [SEMI G38-87] (The "A" part of the abbreviation is written with a subscript capital letter.)
alarm n		1 : implementation-dependent interpretation of an event; supplier- and situation-specific events. [SEMATECH] 2 : any abnormal situation on the equipment based on physical and safety limitations that may endanger people, equipment, or material being processed. The presence of an alarm on equipment typically requires some action to maintain personnel, equipment, or physical material safety. [SEMATECH]
alert		see sign.
algorithm n		a set of precisely defined rules, processes, or operations for solving a problem in a finite number of steps. [SEMATECH]
algorithmic adj		pertaining to problem-solving methods that use a precisely defined, finite set of rules, operations, or procedures. [SEMATECH] Contrast heuristic. Also see algorithm.
align expose n		an operation in a lithography process during which a resist-coated substrate is put into proper relative position or orientation to a reticle and exposed to light. [SEMATECH]
alignment n		1 : the accuracy of the relative position of an image on a reticle with reference to an existing image on a substrate. [SEMATECH] 2 : a procedure in which a wafer is correctly positioned relative to a reticle. [SEMATECH] 3 : the mechanical positioning of reference points on a wafer or flat panel display substrate (also called alignment marks or alignment targets) to the corresponding points on the reticle or reticles. The measure of alignment is the overlay at the positions on the wafer or substrate where the alignment marks are placed. [Adapted from SEMI P18-92 and D8-94] Also see direct alignment and indirect alignment.
alignment mark n		an image selectively placed within or outside an array for either testing or aligning, or both. [ASTM F127-84] Also called alignment key and alignment target.
alignment precision n]		on epitaxial silicon wafers, pattern displacement in the first mask photolithography process. [SEMI M18-94
alignment pocket n		any form of mechanical shape (other than flat) local to a cassette or container designed to position or otherwise externally constrain a container to a production tool. [SEMI E15-90]
alignment target		see alignment mark.
alkali n		any compound that has highly basic properties. Alkalis are often hydroxides of alkali metals (metals that belong to group IA of the periodic table, including Li, Na, K, Rb, Cs, and Fr). [SEMATECH]
alkali metals n		a group of soft, reactive metals with a valence of 1; examples are sodium, potassium, lithium, and rubidium. [SEMATECH]
alkaline-earth metals n		the heaviest members of the group IIa in the periodic table; usually calcium, strontium, magnesium, and barium. [SEMATECH]
alloy n		1 : a composite of two or more elements, of which at least one is metal. [SEMATECH] 2 : a thermal cycle in which two or more discrete layers (of which at least one is metal) react to allow good electrical contacts. [SEMATECH]
alluvial adj		describes soil that contains sediment deposited by water flow. [SEMATECH]
alphanumeric marking n		a system of marking wafers using machine-readable letters, numbers, a dash, or a period. [SEMATECH]
alpha test n		performance testing, done at a manufacturer's site, on a preproduction version of a process tool. Testing is performed by applications engineering under development engineering's supervision. No design changes are made during the testing period. [SEMATECH]
aluminized area n		in a cerdip or cerpack semiconductor package, the leadframe area coated with aluminum to provide a surface suitable for wire bonding. The maximum area is defined by the inside dimension of the cap or ceramic ring. In some cases, the die attach area is also coated if a full leadframe is used. The coating may be vacuum deposited or bonded. [SEMATECH]
aluminized width n		in a semiconductor package, the width of the area coated with a protective layer of aluminum. This area covers most of the top formed width. [SEMATECH] Also see bond finger and aluminized area.
aluminum (Al) n		a metal used to interconnect the devices on a wafer and to interconnect external devices or components. [SEMATECH]
aluminum chloride (AlCl₃) n		a crystalline solid formed in the chambers of aluminum plasma etchers and concentrated in the cold traps. [SEMATECH ]
aluminum oxide (Al₂O₃) n		an abrasive used in grinding operations. Also, the native oxide growth that occurs on freshly deposited aluminum. Sapphire is the monocrystalline form of aluminum oxide. [SEMATECH] Also see single crystal. ambient pressure : in mass flow controllers, the absolute pressure of the medium surrounding the device. [SEMI E28-92]
ambient temperature (TA) n		the temperature of the surrounding medium, such as air or liquid, that comes into contact with the device or apparatus. [SEMATECH] 2 : the temperature of the specified, surrounding medium (such as air, nitrogen, or a liquid) that comes into contact with a semiconductor device being tested for thermal resistance. [SEMI G38-87]
American National Standards Institute (ANSI) n		an organization that compiles and publishes computer industry standards. [SEMATECH]
AMHS		see automated material handling system.
ammonia (NH₃) n		a colorless, alkaline gas that has a pungent odor. It dissolves readily in water and is combustible. Ammonia is used for the chemical vapor deposition of silicon nitride and for the nitrification of silicon oxide. [SEMI C3.12-89]
ammonium fluoride (NH₄F) n		a white crystalline salt used to buffer hydrofluoric acid etches that dissolve silicon dioxide but not silicon. An example of such an etch is the buffered oxide etch. [SEMATECH] Also see pinhole.
ammonium hydroxide (NH₄OH) n		a weak base formed when ammonia is dissolved in water. [SEMATECH]
amorphous silicon n		silicon with no discernible crystalline structure. [SEMATECH] Contrast polycrystalline silicon.

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