Terms and Definitions

A

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] Also see hole.

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. [IEEE]

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, Cmax . [ASTM F1241]

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.

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]

aeolotropic : see anisotropic.

AES (Auger-electron spectrometry)/AES (Atomic-emission spectroscopy)/SAM (Scanning Auger microprobe): see Auger electron spectroscopy.

AFM : see atomic force microscopy.

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.

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]

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 package, bond finger, top formed width, and aluminized area.

ambient temperature (TA) 1 : 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]

ammonium fluoride (NH4 F) : 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 (NH4 OH) : a weak base formed when ammonia is dissolved in water. [SEMATECH]

amorphous silicon : silicon with no discernible crystalline structure. [SEMATECH] Contrast polycrystalline silicon.

analog adj : A signal in an electronic circuit that takes on a continuous range of values rather than only a few discrete values; a circuit or system that processes analog signals. [1994 National Technology Roadmap for Semiconductors] Contrast discrete.

angle-resolved scattering (ARS) n : technique that measures light scattered from particles as a function of angle; used to characterize particles. [SEMATECH]

angstrom (Å) n : unit of linear measure equal to one ten billionths of a meter (10 -10 m). (The diameter of a human hair is approximately 750,000 Å.) The preferred SI unit is nanometers. 10 Å = 1 nm. [SEMATECH]

anion n : an ion that is negatively charged. [SEMATECH]

anisotropic adj : exhibiting different physical properties in different directions. NOTE—In semiconductor technology, the different directions are defined by the crystallographic planes. [SEMI M1- 94 and ASTM F1241] Also called nonisotropic and aeolotropic. Also see anisotropic etch.

anisotropic etch n : a selective etch that exhibits an accelerated etch rate along specific crystallographic planes. NOTE—Anisotropic etches are used to determine crystal orientation, to expose crystal defects, and to facilitate dielectric component isolation. [SEMI M1-94 and ASTM F1241] Also called preferential etch. Also see anisotropic.

anneal n : a high-temperature operation that relieves stress in silicon, activates ion-implanted dopants, reduces structural defects and stress, and reduces interface charge at the silicon-silicon dioxide interface. [SEMATECH]

anomaly : see defect.

antireflective coating (ARC) n : a layer of dielectric material deposited on a wafer before resist to minimize reflections during resist exposure. [SEMATECH]

ARC : see antireflective coating.

architecture n : of a computer system, a defined structure based on a set of design principles. The definition of the structure includes its components, their functions, and their relationships and interactions. [SEMATECH]

area contamination n : foreign matter on localized portions of a wafer or substrate surface. [SEMI M3-88]

artifact n 1 : a physical standard against which a parameter is measured; for example, a test wafer used for testing parametric drift in a machine. [SEMATECH] Also called standard reference material. 2 : a superficial or unessential attribute of a process or characteristic under examination; for example, a piece of lint on a lens that appears through a microscope to be a defect on a die. [SEMATECH] 3 : in surface characterization, any contribution to an image from other than true surface morphology. Examples include contamination, vibration, electronic noise, and instrument imperfections. [SEMATECH]

ash v : to apply heat to a material until the material has been reduced to a mineral residue. [SEMATECH]

asher n : a machine used to remove resist from substrates. [SEMATECH]

ashing n : the operation of removing resist from a substrate by oxidation; a reaction of resist with oxygen to remove the resist from the substrate. [SEMATECH]

aspect ratio n 1 : in etch, the depth-to-width ratio of an opening on a wafer. [SEMATECH] 2 : in feature profile, the height-to-width ratio of a feature. [SEMATECH]

atomic force microscopy (AFM) n : a microscopy technique based on profilometry using an atomically sharp probe that provides three-dimensional highly magnified images. During AFM, the probe scans across a sample surface. The changes in force between the sample and the probe tip cause a deflection of the probe tip that is monitored and used to form the magnified image. [SEMATECH]

atomic percent n : in electron spectroscopy for chemical analysis (ESCA) of plastic surface composition, the number of atoms of a particular element present in every hundred atoms within the ESCA detection volume. [SEMATECH]

ATPG : see automatic test pattern generation.

at-speed test n : any test performed on an integrated circuit that tests the device at its normal operating clock frequency. [1994 National Technology Roadmap for Semiconductors]

Auger electron spectroscopy (AES) n : the energy analysis of Auger electrons produced when an excited atom relaxes by a radiationless process after ionization by a high-energy electron, ion, or X-ray beam. [SEMATECH]

Auger process n : the radiationless relaxation of an atom involving a vacancy in an inner electron shell. An electron is emitted, which is referred to as an Auger electron. [ASTM E673-90]

autodoping n : in the manufacture of silicon epitaxial wafers, the incorporation of dopant originating from the substrate into the epitaxial layer. [SEMI M1-94 and ASTM F1241] Also called self-doping. Also see doping and substrate.

automatic test pattern generation (ATPG) n : the automatic development of vectors that, when applied to an integrated circuit, permit faults to be detected in the performance of the integrated circuit. [1994 National Technology Roadmap for Semiconductors]

B

back-end of line (BEOL) n : process steps from contact through completion of the wafer prior to electrical test. Also called back end. [SEMATECH]

backgrind n : an operation using an abrasive on the back side of a substrate to achieve the necessary thinness for scribing, cutting, and packaging of die. [SEMATECH]

back oxide n : a layer of silicon dioxide formed on the back of a wafer during oxidation. [SEMATECH]

backside : see back surface.

back surface n : of a semiconductor wafer, the exposed surface opposite to that on which active semiconductor devices have been or will be fabricated. [ASTM F1241] Also called backside.

bake n : in wafer manufacturing, a process step in which a wafer is heated in order to harden resist, remove moisture, or cure a film deposited on the wafer. [SEMATECH]

ball-grid array (BGA) n : an integrated circuit surface mount package with an area array of solder balls that are attached to the bottom side of a substrate with routing layers. The die is attached to the substrate using die and wire bonding or flip-chip interconnection. [SEMATECH] Also called land-grid array, pad-grid array, or pad-array carrier.

bar : see die, crossbar, and bar end.

bare die n : individual, unpackaged silicon integrated circuit. [1994 National Technology Roadmap for Semiconductors]

barrier n : a physical layer designed to prevent intermixing of the layers above and below the barrier layer; for example, titanium- tungsten and titanium-nitride layers. [SEMATECH]

barrier layer : see depletion layer.

base n 1 : in semiconductor manufacturing chemicals, a substance that dissociates in water to liberate hydroxyl ions, accepts a proton, has an unshared pair of electrons, or reacts with acid to form a salt. A base has a pH greater than seven and turns litmus paper blue. [SEMATECH] 2 : in facilities and safety, a corrosive material with the chemical reaction characteristic of an electron donor. [SEMI S4-92] 3 : in quartz and high temperature carriers, the material at the bottom of a wafer carrier on which the wafer carrier rests when placed on a flat surface. [SEMI E2-93] 4 : of a cerdip or cerpack package, the bottom ceramic portion. A leadframe, a window frame, and the cap are attached to the base--generally with devitrifying solder glass--during package/device manufacture. [SEMI G1-85] Also see cap and window frame.

behavioral n : a level of logic design that involves describing a system at a level of abstraction that does not involve detailed circuit elements, but instead expresses the circuit functionality linguistically or as equations. [1994 National Technology Roadmap for Semiconductors]

BEOL : see back-end of line.

BGA : see ball grid array.

biCMOS design n : the combination of bipolar and complementary metal oxide semiconductor design and processing principles on a single wafer or substrate. [SEMATECH]

bimetal mask : see mask, bimetal.

binding energy n : the value obtained by subtracting the instrumentally measured kinetic energy of an electron from the energy of the incident photon, corrected for an instrument work function. [SEMATECH]

bipolar technology n : a semiconductor device fabrication technology that produces transistors which use both holes and electrons as charge carriers. [SEMI M1-94 and ASTM F1241]

bird's beak n : a structural feature produced as a result of the lifting of the edges of the nitride layer during subsequent oxidation. [SEMATECH]

BIST : see built-in self test.

blister ceramic n : an enclosed, localized separation within or between the layers of a ceramic package that does not expose an underlying layer of ceramic or metallization. [SEMI G61-94] Also called bubble ceramic.

blister metal n : in packaging, an enclosed, localized separation of a metallization layer from its base material (such as ceramic or another metal layer) that does not expose the underlying layer. [SEMI G8-94] Also called bubble metal, blister metallization, and bubble metallization. Also see package.

bonding pad n : relatively large metal areas on a die used for electrical contact with a package or probe pins. [SEMATECH]

boundary scan n : a scan path that allows the input/output pads of an integrated circuit to be both controlled and observed. [1994 National Technology Roadmap for Semiconductors]

bridge n 1 : a defect in which two adjacent areas connect because of misprocessing such as poor lithography, particle contamination, underdevelopment, or etch problems. [SEMATECH] Also called short. 2 : software that allows access to, and combination of, data from incompatible databases. [SEMATECH]

bridging fault n : a fault modeled as a short-circuit between two nets on a die. [1994 National Technology Roadmap for Semiconductors]

brightfield illumination n (transmission electron microscopy) : the illumination of an object so that it appears on a bright background. [ASTM E7-93]

buffered hydrofluoric acid n : an extremely hazardous corrosive used to etch silicon dioxide from a wafer. This acid has a 20- to 30-minute reaction delay after contact with skin or eyes. [SEMATECH]

built-in self test (BIST) : any of the methods of testing an integrated circuit (IC) that use special circuits designed into the IC. This circuitry then performs test functions on the IC and signals whether the parts of the IC covered by the BIST circuits are working properly. [1994 National Technology Roadmap for Semiconductors]

buried contact n : a conductive region between two less conductive regions. [SEMATECH]

buried layer n 1 : a conductive layer between two less conductive films; for example, a localized n+ region in a p-type wafer that reduces the npn collector series resistance for integrated circuit transistors fabricated in an n-type epitaxial layer deposited on the p-type wafer. [SEMATECH] 2 : in epitaxial silicon wafers, a diffused region in a substrate that is, or is intended to be, covered with an epitaxial layer. [SEMI M18-94 and ASTM F1241] Also called subdiffused layer and diffusion under film.

burn-in n : the process of exercising an integrated circuit at elevated voltage and temperature. This process accelerates failure normally seen as "infant mortality" in a chip. [1994 National Technology Roadmap for Semiconductors] Also see infant mortality.

C

C4 (controlled collapse chip connect) : see flip chip.

cap deposition : see passivation.

carrier n 1 : an entity capable of carrying electric charge through a solid; for example, mobile holes and condition electrons in semiconductors. [SEMI M1-94 and ASTM F1241] Also called charge carrier. Also see majority carrier and minority carrier. 2 : slang for wafer carrier. [SEMATECH]

cavity-down packages n : in cofired ceramic packages, packages on which the die surface faces the mounting board. [SEMI G61-94]

cavity-up packages n : in cofired ceramic packages, packages on which the die surface faces away from the mounting board. [SEMI G61-94]

cerdip : abbreviation for ceramic dual-in-line package. See dual-in-line package.

cerpack : abbreviation for ceramic package.

channel n : a control region through which the principal current charge pass and whose cross-section is determined by the voltage applied to a gate, the principal current being the result of an applied field [JESD77].

chemical-mechanical polish (CMP) n : a process for the removal of surface material from a wafer. The process uses chemical and mechanical actions to achieve a mirror-like surface for subsequent processing. [SEMI M1-94 and ASTM F1241] Also called chem-mech polish.

chemical vapor deposition (CVD) n : in semiconductor technology, a process in which a controlled chemical reaction produces a thin surface film. [SEMI M1-94 and ASTM F1241] Contrast physical vapor deposition.

chem-mech polish : See chemical-mechanical polish.

chip n 1 : in semiconductor wafers, a region where material has been unintentionally removed from the surface or edge of the wafer. [ASTM F1241] Contrast indent. 2 : see die. 3 : in packaging, a region of material missing from a component; for example, ceramic from a package or solder from a preform. The region does not progress completely through the component and is formed after the component is manufactured. The chip size is given by its length, width, and depth from a projection of the design plan-form. [SEMI G61-94] Also called chip-out. Contrast pit. 4 : in flat panel display substrates, a region of material missing from the edge of the glass substrate, which is sometimes caused by breakage or handling. [SEMI D9-94]

chip carrier (CC) n 1 : a small footprint semiconductor package generally with terminals on all four sides. The package may be manufactured by cofired ceramic or multilayer printed circuit board technologies. [SEMATECH] 2 n : a low profile package whose chip cavity or mounting area occupies a major fraction of the package area and whose terminals consist of metal pad surfaces (on the leadless versions) or leads formed around the sides and under the package or out from the package (on leaded versions) [JESD99, JESD30]. Also see castellation and ceramic chip carrier.

chip-out : synonym for chip (see definition 1).

circuit n : the combination of a number of connected electrical elements or parts to accomplish a desired function. [SEMATECH]

circuit design n : techniques used to connect active (transistors) and passive (resistors, capacitors, and inductors) elements in a manner to perform a function (that is, logic, analog). [1994 National Technology Roadmap for Semiconductors]

circuit geometries n : the relative shapes and sizes of features on a die. [SEMATECH]

CMOS : see complementary metal oxide semiconductor.

CMP : see chemical-mechanical polish.

comet n : on a substrate, a buildup of resist shaped like a comet and generated by a defect. [SEMI P3-90] Also called motorboat.

complementary metal oxide semiconductor (CMOS) technology n 1 : a fabrication process that incorporates p-channel and n-channel MOS transistors within the same silicon substrate. [SEMATECH] 2 n : a technology for combining p-channel and n-channel transistors in a single chip integrated circuit [JESD99].

component n 1 : an individual electronic part, such as a device, diode, or capacitor that is fabricated in a metal oxide semiconductor or bipolar process. [SEMATECH] 2 : an individual piece or a complete assembly of individual pieces, including industrial products that are manufactured as independent units, capable of being joined with other pieces or components. The typical components referred to by the specification are valves, fittings, regulators, gauges, instrument sensors, a single length of tubing, several pieces of tubing welded together, tubing welded to fittings, and the like. [SEMI F1-90] 3 : the fundamental parts of an object, its entities, or relationships. [SEMATECH] 4 : the hardware and software that work in sets (functional entities) to perform the operation(s). [SEMATECH]

conchoidal fracture n : a fracture having smooth convexities and concavities like a clamshell. [SEMATECH] Also see chip.

conductor n : a substance through which electricity can readily flow. Contrast insulator. [SEMATECH]

contact n : in an oxide layer, an opening that allows electrical connection between metal and silicon layers. [SEMATECH] Also see window and via.

contamination n 1 : the presence of particles, chemicals, and other undesirable substances, such as on or in a process tool, in a process liquid, or in a cleanroom environment. [SEMATECH] Also see area contamination and particulate contamination. 2 : three- dimensional foreign material adhering to a package (plastic or ceramic) or leadframe, or parent material displaced from its normal location and similarly adhered. Adherence means that the particle cannot be removed by an air or nitrogen blast at 20 psi. [SEMATECH] Also see foreign material and stain.

controlled collapse chip connect (C4) : see flip chip

correlation n 1: a relation existing between phenomena or things or between mathematical or statistical variables which tend to vary, be associated, or occur together in a way not expected on the basis of chance alone. [Webster's Dictionary]

crack n 1 : on semiconductor wafers, a cleavage or fracture that extends to the surface and may or may not pass through the entire thickness of the wafer. [ASTM F1241] 2 : of a semiconductor package or solder preform, a cleavage or fracture that extends to the surface. The crack may or may not pass through the entire thickness of the package or preform. [SEMI G61-94] 3 : in flat panel display substrates, a fissure located at the sheet edge or central area. [SEMI D9-94]

crater n : on the surface of a slice or wafer, an individually distinguishable bowl-shaped cavity. A crater is visible when viewed under diffused illumination. [SEMATECH]

cratering n : on a slice or wafer, a surface texture of irregular closed ridges with smooth central regions. [ASTM F1241]

crescents n : structures with parallel major axes, attributed to substrate defects either above or below the surface plane of silicon substrates after epitaxial deposition. [ASTM F1241] Also see fishtails.

critical area n : the area in which the center of a defect must occur to cause a failure or fault. [SEMATECH] Also see fault and fault probability.

critical dimension (CD) n : the width of a patterned line or the distance between two lines, monitored to maintain device performance consistency; that dimension of a specified geometry that must be within design tolerances. [ASTM F127-84] Also see linewidth.

crosstalk n : the undesirable addition of one signal to another in a circuit usually caused by coupling through parasitic elements. An example would be inductive or capacitive coupling between adjacent conductors. [1994 National Technology Roadmap for Semiconductors]

crossunder n : on a die, the point at which a conductor crosses under a second conductor without making electrical contact. [SEMATECH]

crow's foot n : on a semiconductor wafer, intersecting cracks in a pattern resembling a "crow's foot" Y on {111} surfaces and a cross " " on {100} surfaces. [ASTM F1241]

crystal n : a solid composed of atoms, ions, or molecules arranged in a pattern that is periodic in three dimensions. [ASTM F1241]

crystal defect n : departure from the regular arrangement of atoms in the ideal crystal lattice. [ASTM F1241] Also see crystal lattice and damage.

crystal indices : see Miller indices. Also see crystallographic notation.

crystal lattice n : in a crystal, the three-dimensional and repeating pattern of atoms. [SEMATECH]

crystallographic notation n : a symbolism based on Miller indices used to label planes and directions in a crystal as follows: (111) plane [111] direction {111} family of planes <111> family of directions. [SEMI M1-94 and ASTM F1241]

crystal originated particle (COP) n : a surface depression that is formed during soft alkaline chemical treatment of silicon wafer surfaces that contain crystal defects at or close to the wafer surface and that scatters light similarly to a very small particle. [ASTM F1241] Also called surface micro defect.

CTE : see coefficient of thermal expansion.

CVD : see chemical vapor deposition.

cycle time n : (1) the length of time required for a wafer to complete a specified process or set of processes. [SEMATECH] (2) the length of time required to complete a failure analysis job from receipt in the failure analysis lab to the time results (written or verbal) are communicated back to the immediate requestor. [Sandia Labs] Also see equipment cycle, minimum theoretical cycle time, and theoretical cycle time.

D

damascene n : an integrated circuit process by which a metal conductor pattern is embedded in a dielectric film on the silicon substrate. The result is a planar interconnection layer. The creation of a damascene structure most often involves chemical mechanical polishing of a nonplanar surface resulting from multiple process steps. A damascene trench is a filled trench. [1994 National Technology Roadmap for Semiconductors]

damage n 1 : of a single-crystal silicon specimen, a defect of the crystal lattice in the form of irreversible deformation that results from mechanical surface treatments such as sawing, lapping, grinding, sandblasting, and shot peening at room temperature without subsequent heat treatments. [ASTM F1241] Also see crystal lattice. 2 : any yield or reliability detractors other than those related to design, process specification violations, or particles. [SEMATECH]

DC test : A sequence of direct current (DC) measurements performed on integrated circuit pads to determine probe contact, leakage currents, voltage levels on input and output, power supply currents, etc. [1994 National Technology Roadmap for Semiconductors]

deep level impurity n : a chemical element that, when introduced into a semiconductor, has an energy level (or levels) that lies on the midrange of the forbidden energy gap, between the energy levels of the dopant impurity species. [ASTM F1241]

defect n : for silicon crystals, a chemical or structural irregularity that degrades the ideal silicon crystal structure or the thin films built over the silicon wafer. 2 : a pit, tear, groove, inclusion, grain boundary, or other surface feature that is either characteristic of the material or a result of its processing and that is not a result of the sample preparation. [SEMATECH] Also called anomaly.

defect density n : the number of imperfections per unit area, where imperfections are specified by type and dimension. [ASTM F127-84] Also see defect.

defect level n : the number of die in parts-per-million that are shipped to customers and that are defective even though the test program declares them to be good. [1994 National Technology Roadmap for Semiconductors]

defect, photomask n : any flaw or imperfection in the opaque coating or functional pattern that will reproduce itself in a resist film to such a degree that it is pernicious to the proper functioning of the microelectronic device being fabricated. [SEMI P2-86]

delamination n : in a cofired ceramic package, chip carrier, dual inline, pin grid array, etc., the separation of one ceramic layer from another. [SEMI G61-94] Also see package.

delay fault n : a fault that has the effect of causing a signal to appear late in arriving at a destination. [1994 National Technology Roadmap for Semiconductors]

design for test (DFT) n : design of logic circuits to facilitate electrical testing. [SEMATECH]

destructive physical analysis n 1: the examination and testing of components to ensure proper operation and behavior. [Sandia Labs]

device n : a specific kind of electronic component (such as an MOS transistor, resistor, diode, or capacitor) on a die. The diode and transistor are referred to as active devices; the capacitor and resistor, as passive devices. [SEMATECH]

dew point n : the temperature at which liquid first condenses when vapor is cooled. [SEMI C3-94]

DFT : see design for test.

die n (sing or pl) : a small piece of silicon wafer, bounded by adjacent scribe lines in the horizontal and vertical directions, that contains the complete device being manufactured. [SEMATECH] Also called chip and microchip. Obsolete: bar, slice.

die attach area n : the nominal area designated for die attaching to the package or leadframe. [SEMI G22-86] Contrast effective die attach area and die attach pad.

die attach pad n : the nominal area designated for die attaching to the package or leadframe.. Die attach pad is usually applied to leadframes. The term die attach area is usually applied to ceramic packages. [SEMATECH] Also see package and die.

die attach surface n : in a ceramic semiconductor package, a dimensional outline designated for die attach. [SEMI G33-90] Also see package and die.

die bonding (D/B) : an assembly technique that bonds the back side of an integrated circuit die to a substrate, header, or leadframe. [SEMATECH]

dielectric n 1 : a nonconductive material; an insulator. Examples are silicon dioxide and silicon nitride. [SEMATECH] 2 : a material applied to the surface of a ceramic or preformed plastic package to provide functions such as electrical insulation, passivation of underlying metallization, and limitations to solder flow. [SEMI G33-90]

dielectric isolation (DI) n : a nonconductive barrier layer grown or deposited between two adjacent regions on a die to prevent electrical contact between the regions. [SEMATECH] Also see isolation.

diffusion n : a high-temperature process in which desired chemicals (dopants) on a wafer are redistributed within the silicon to form a device component. [SEMATECH]

dimple n : on a semiconductor wafer, a shallow depression in a wafer surface with a concave, spheroidal shape and gently sloping sides. NOTE—Dimples are macroscopic features that are visible to the unaided eye under proper lighting conditions. [ASTM F1241]

DIP : acronym for "dual-in-line package".

dislocation n : a line imperfection in a crystal that either forms the boundary between slipped and nonslipped areas of a crystal or is characterized by a closure failure of the Burger's circuit. [ASTM F1241] Also called line defect. Also see slip.

dopant n : in silicon technology, a chemical element incorporated in trace amounts in a semiconductor crystal or epitaxial layer to establish its conductivity type and resistivity. [Adapted from SEMI M9-90 and M8-84] Also see conductivity type, n-type, and p-type.

dopant density n : in an uncompensated extrinsic semiconductor, the number of dopant impurity atoms per unit volume, usually given in atoms/cm3 , although the SI unit is atoms/m3 . Symbols: ND for donor impurities and NA for acceptor impurities. [ASTM F1241]

doping n : the addition of impurities to a semiconductor to control the electrical resistivity. [SEMI M1-94 and ASTM F1241]

drain n : one of the three major parts of a complementary metal oxide semiconductor transistor. [SEMATECH]

drain region n : a collection region that acquires principal-current charge carriers from a channel, the current being due to a voltage applied to the drain [JESD77].

E

edge crown n : an increase of epitaxial layer thickness around the periphery of the wafer arising from differences in deposition rate. [SEMATECH]

electrostatic discharge (ESD) n 1 : a sudden electric current flow, such as between a human body and a metal oxide semiconductor semiconductor, with potential damage to the component. [SEMATECH] 2 : the transfer of electrostatic charge between bodies at different electrostatic potentials. [SEMI E33-94]

energy-dispersive X-ray spectrometer n : a detector used to determine which elements are present in a sample by analyzing X-ray fluorescence for energy levels that are characteristic of each element. [SEMATECH]

epitaxial layer n : in semiconductor technology, a layer of a single crystal semiconducting material grown on a host substrate which determines its orientation. [SEMI M2-94 and ASTM F1241 ]

epitaxy (epi) n : a silicon crystal layer grown on top of a silicon wafer that exhibits the same crystal structure orientation as the substrate wafer with a dissimilar doping type or concentration or both. Examples are p/p , n/n , n/p, and n/n. [SEMATECH] Also see epitaxial layer.

ESD : see electrostatic discharge.

etch 1 n : a category of lithographic processes that remove material from selected areas of a die. Examples are nitride etch and oxide etch. [SEMATECH] 2 : in the manufacture of silicon wafers, a solution, a mixture of solutions, or a mixture of gases that attacks the surfaces of a film or substrate, removing material either selectively or nonselectively. [SEMI M1-94 and ASTM F1241] Also see anisotropic etch, preferential etch, dry plasma etch, reactive ion etch, and wet chemical etch.

etchant n : an acid or base (in either liquid or gaseous state) used to remove unprotected areas of a wafer layer. Examples are potassium hydroxide, buffered oxide etch, and sulfur hexafluoride. [SEMATECH]

etch pit n : a pit, resulting from preferential etching, localized on the surface of a wafer at a crystal defect or stressed region. [ASTM F1241]

eutectic n : alloy or solution with components distributed in the proportions necessary to minimize the melting point. [SEMATECH]

excessive leakage n : in the testing of semiconductors, current that is above the specified limit for the particular test being conducted. [Sandia Labs]

F

failure n 1 : the loss of ability of a component to meet the electrical or physical performance specifications that (by design or testing) it was intended to meet [JESD29] 2 n : a component that has failed [JESD29].

failure mechanism n : in failure analysis, a fundamental process or defect responsible for a failure. [SEMATECH]

failure mode n : in failure analysis, the electrical symptoms by which a failure is observed to occur. Failure mode types include a catastrophic failure that is both sudden and complete and degraded failure that is gradual, partial, or both, as well as intermittent failures. [Sandia Labs]

failure mode and effects analysis (FMEA) n : an analytically derived identification of the conceivable semiconductor failure modes and the potential adverse effects of those modes on the system and mission. [SEMATECH]

fault n 1 : an accidental condition that causes a functional unit to fail to perform its required function. [SEMATECH] 2 : a defect- causing out-of-spec operation of an integrated circuit. [SEMATECH] Also see exception condition and defect.

fault coverage n : the percentage of a particular fault type that a test vector set will detect when applied to a chip. [1994 National Technology Roadmap for Semiconductors]

fault dictionary n : a list of faults that a test vector will detect in a failing circuit, or a list of all such faults for each vector in a vector set. [1994 National Technology Roadmap for Semiconductors]

fault model n : a model of the behavior of defective circuitry in an integrated circuit. Physical defects result in improper behavior in a circuit that must be modeled in order for test patterns to be designed to properly detect them. Examples include stuck-at model, timing model, and bridging model. [1994 National Technology Roadmap for Semiconductors]

FET : see field-effect transistor.

FIB : see focused ion beam

field-effect transistor (FET) n 1 : a transistor consisting of a source, gate, and drain, the action of which depends on the flow of majority carriers past the gate from the source to the drain. The flow is controlled by the transverse electric field under the gate. [SEMATECH] 2 n : a transistor in which the condition is due entirely to the flow of majority carriers through a conduction channel controlled by an electric field arising from a voltage applied between the gate and the source [JESD77].

fishtails n : structures, attributed to substrate defects, either above or below the surface plane after epitaxial deposition; the "tails" are aligned in a particular crystallographic direction. [ASTM F1241] Also see crescents.

fissure : see crack.

flake n : material missing from one but not the other side of a semiconductor wafer. [SEMI M10-89]

flake chip : see chip and peripheral chip.

flaking : see peeling.

flip-chip n : a leadless, monolithic structure that contains an integrated circuit designed to electrically and mechanically interconnect to a hybrid circuit. Connection is made to bump contacts covered with a conductive bonding agent on the face of the hybrid. [SEMATECH] Also called controlled collapse chip connect or C4

fluorescence n : the emission of light as the result of, and only during, the absorption of radiation of shorter wavelengths. [IEEE]

Fluorescent Microthermographic Imaging n : a failure analysis technique that uses a temperature dependent fluorescent compound and an optical pumpiing source to image temperature changes on a semiconductor device with near optical spatial resolution. [Sandia Labs]

FMEA : see failure mode and effects analysis.

FMI : see Fluorescent Microthermographic Imaging.

Fourier Transform Infrared Spectroscopy n : an analytical tool to determine the composition of a material using an infrared laser.

Focused ion beam (FIB) n : an imaging tool that can be used to deposit or etch materials on wafers. A focused ion beam is often used in the etch mode to selectively cleave structures for failure analysis. It is also used in photomask repair for removing or adding material, as necessary, to make the photomask defect free. [SEMATECH]

Front end of line (FEOL) n 1: in semiconductor processing technology, all processes from wafer start through final contact window processing [SEMATECH].

FTIR : see Fourier transform infrared spectroscopy.

functional pattern : see pattern, functional.

functional probe n : the electronic testing of die on a wafer to determine conformance to specifications. [SEMATECH]

functional test n : one or more tests to determine whether a circuit's logic behavior is correct. [1994 National Technology Roadmap for Semiconductors]

G

gate n : an electrode that regulates the flow of current in a metal oxide semiconductor transistor. [SEMATECH]

gate electrode n : the electrode of a metal oxide semiconductor field effect transistor (MOSFET); it controls the flow of electrical current between the source and the drain. [SEMATECH]

gate oxide n : a thin, high-quality silicon dioxide film that separates the gate electrode of a metal oxide semiconductor transistor from the electrically conducting channel in the silicon. [SEMATECH]

glass n : a deposited film of silicon dioxide with additives to adjust coefficient of thermal expansion, color, conductivity, and melting point, generally doped with boron or phosphorus or both. [SEMATECH] Also see silicon dioxide.

groove n : in a semiconductor wafer, a shallow scratch with rounded edges that is usually the remnant of a scratch not completely removed by polishing. [SEMI M1-94 and ASTM F1241]

growth hillock : see pyramid.

H

hermetic seal n : a coat applied in the final stage of thermal processing to seal the ceramic package and to protect the device from the external environment. [SEMATECH]

hillock n : a defect caused by stress that raises portions of a metal (such as aluminum) film above the surface of the film. Localized stress within the metal film may elevate portions of the film through the adjacent dielectric layer, resulting in a metal extrusion and a short to the next metal layer. [SEMATECH] Also see pyramid.

hole n 1 : of a semiconductor, a mobile vacancy in the electronic valence structure that acts like a positive electron charge with positive mass; the majority carrier in p-type material. [SEMI M1-94 and ASTM F1241] 2 : in plastic and metal wafer carriers, the area through which a pin from another wafer carrier can enter for the transfer of wafers. [SEMI E1-86] Also see wafer carrier.

hot carriers n : those carriers, which may be either electrons or holes, that have been accelerated by the large traverse electric field between the source and the drain regions of a metal oxide semiconductor field-effect transistor (MOSFET). They can jeopardize the reliability of a semiconductor device when these carriers are scattered (that is, deflected) by phonons, ionized donors or acceptors, or other carriers. The scattering phenomenon can manifest itself as substrate current, gate current, or trapped charges. [SEMATECH] Also see trapped charges.

I

IC : see integrated circuit.

IDDQ : abbreviation for direct drain quiescent current. An electrical parameter associated with the current of a CMOS integrated circuit when in a static (quiescent) condition, that is, no changing signals applied to the IC.

impact test n : in component testing, a test performed to determine particle contribution as a result of mechanical shock to the component. [SEMATECH] Also called particle impact noise detection or PIND

implant : see ion implantation.

impurity n : a chemical or element added to silicon to change the electrical properties of the material. [SEMATECH] Also see dopant, ion implantation.

inclusion n : discrete second phases (oxides, sulfides, carbides, intermetallic compounds) that are distributed in a metal matrix. [SEMATECH]

indent n : on a semiconductor wafer, an edge defect that extends from the front surface to the back surface. [ASTM F1241] Contrast chip.

insulator n : a substance that will not conduct electricity; for example, silicon dioxide and silicon nitride. [SEMATECH] Contrast conductor.

integrated circuit (IC) n 1 : two or more interconnected circuit elements on a single die. [SEMATECH] 2 : a fabrication technology that combines most of the components of a circuit on a single-crystal silicon wafer. [SEMI Materials, Vol. 3, Definitions for Semiconductor Materials]

interference contrast microscope n : a microscope that reveals surface details of an object in which there is no appreciable absorption by using the interference between two beams of light. [Adapted from ASTM F1241] Also called Nomarski Interference Contrast

interlevel dielectrics n : an insulating film between two conductive film layers, as between poly and aluminum or between layers of aluminum. [SEMATECH]

interstitial n : in a crystalline solid, an atom that is not located on a lattice site. [SEMATECH]

intrinsic semiconductor n : a semiconductor in which the density of electrons and holes is approximately equal. [SEMATECH] Contrast extrinsic semiconductor.

ion implantation (I 2 , II) n : a high-energy process that injects an ionized species such as boron, phosphorus, arsenic, or other ions into a semiconductor substrate. [SEMATECH]

I/O pins n : connections to an integrated circuit through which input and/or output (I/O) signals pass. [1994 National Technology Roadmap for Semiconductors]

isolation n : an electrical separation of regions of silicon on a wafer; for example, boron diffusion to isolate a transistor. [SEMATECH] Also see dielectric isolation.

J

junction spiking n : the penetration of a junction by aluminum, which occurs when silicon near the junction dissolves in aluminum and migrates along the interconnect lines. Aluminum then replaces silicon at the junction. [SEMATECH]

K

Kirkendall void n : voids induced in a diffusion couple between two metals that have different interdiffusion coefficients. [SEMATECH]

L

large scale integration (LSI) n : the placement of at least 100 active devices on a single die. [JESD99]

laser-scattering light event n : a signal pulse that exceeds a preset threshold, generated by the interaction of a laser beam with a localized light scatterer (LLS) at a wafer surface as sensed by a detector. [ASTM F1241] Also see haze.

layout n 1 : the physical geometry of a circuit or die. [1994 National Technology Roadmap for Semiconductors] 2 : the process of creating the physical geometry of a circuit or die. [1994 National Technology Roadmap for Semiconductors] 3 : see composite drawing.

LDD : see lightly doped drain.

life test n : in semiconductor reliability, a test designed to operate the semiconductor until it fails by elevating both temperature and voltage to accelerate the aging process. [Sandia Labs]

lightly doped drain (LDD) n : a metal-oxide semiconductor (MOS) device design in which the drain doping is reduced to improve breakdown voltage. [SEMATECH]

line defect : see dislocation.

LSI : see large scale integration.

M

Medium Scale Integration (MSI) n : the placement of at between 12 and 100 active devices on a single die. [JESD99]

metallization void n : the absence of a clad, evaporated, plated, or screen printed metal layer or braze from a designated area. [SEMI G58-94] Also called metal void.

metal void : see metallization void.

MFM-CCI : see magnetic current imaging.

microchip : see die.

moon crater n : on a semiconductor wafer, surface texture that results when a wafer floats during the initial stages of chemical polishing in a rotating cup etcher. [ASTM F1241]

motorboat : see comet.

mottled adj : pertaining to the existence on a wafer of material in a window that prevents the window from being properly opened. [SEMATECH]

mound n : on a semiconductor wafer, an irregularly shaped projection on a semiconductor wafer surface with one or more irregularly developed facets. [ASTM F1241] Contrast pyramid. Also see haze.

mouse nip n : a semicircular intrusion into a straight edge of a film or etched pattern on a wafer or reticle. [SEMATECH] Also called mouse bite.

N

nick : see chip.

notch n 1 : an unexpected intrusion or reduction of linewidth in patterned geometries. May also be a V-shaped intrusion into the perimeter of a wafer. The intrusion is used to align the wafer during process. [SEMATECH] 2 : on a semiconductor wafer, an intentionally fabricated indent of specified shape and dimensions oriented such that the diameter passing through the center of the notch is parallel with a specified low index crystal direction. [SEMI M1-94 and ASTM F1241]

O

oil canning n : in metal lid/preform assembly, lid concavity after sealing. [SEMI G53-92]

overcoat : see passivation.

oxide defect n : an area of missing oxide on the back surface of back-sealed wafers discernible to the unaided eye. [ASTM F1241]

oxide etch n : an etch process in which unprotected areas of the oxide layer are eroded by use of a chemical to expose the underlying layer. [SEMATECH]

P

parametric test n : wafer-level testing of discrete devices such as transistors and resistors. [SEMATECH]

parasitic circuit element n : a circuit element that is an unavoidable adjunct of one or more other circuit elements

particle n 1 : a minute quantity of solid or liquid matter. [SEMATECH] 2 : in the manufacture of photolithographic pellicles, material that can be distinguished from the film, whether on the film surface or embedded in the film. [SEMI P5- 94] 3 : the replating step in which a catalytic material, often a palladium or gold compound, is absorbed on a surface to act as sites for initial stages of deposition. [ASTM B374-93]

particulate n 1 : discrete particle of dirt or other material. [ASTM F1241] 2 n (dust) : discrete particle of material that can usually be removed by (nonetching) cleaning. [SEMI M10- 89] 3 adj : describes material in small, discrete pieces; anything that is not a fiber and has an aspect ratio of less than 3 to 1. Examples are dusts, fumes, smokes, mists, and fogs. [SEMATECH]

particulate contamination n : on a semiconductor wafer, a particle or particles on the surface of the wafer. [ASTM F1241]

passivation n : deposition of a scratch-resistant material, such as silicon nitride and/or silicon dioxide, to prevent deterioration of electronic properties caused by water, ions, and other external contaminants. The final deposition layer in processing. [SEMATECH] Also called overcoat and cap deposition.

peeling n : any separation of a plated, vacuum deposited, or clad metal layer from the base metal of a leadframe, lead, pin, heatsink, or seal ring, from an underplate, or from a refractory metal on a ceramic package. Peeling exposes the underlying material. [SEMI G61-94] Also called flaking. Contrast blister metal.

peripheral chip n 1 : crystallographic damage along the circumference of a wafer. [SEMATECH] 2 : on a wafer surface, shallow crater formed in the periphery of the specimen through conchoidal fracture and resultant spalling. [ASTM F1241] Also called flake chip or surface chip.

pinhole n 1 : a minute defect or void in a film, mask, or resist, usually the result of contaminants. [SEMATECH] 2 : a small opening that extends through a covering, such as a resist coating or an oxide layer on a wafer. [SEMI P2-86]

pit n 1 : in a wafer surface, a depression in a wafer surface that has steeply sloped sides that meet the surface in a distinguishable manner, in contrast to the rounded sides of a dimple. [ASTM F1241] Also see slip and dislocation. 2 : in semiconductor packages, plastic or ceramic, or in the leadframes, a shallow depression or crater. The bottom of the depression must be visible in order for the term to apply. A pit is formed during the component manufacture. [SEMI G61-94] Contrast chip. 3 : in flat panel display substrates, a small indentation on the glass substrate surface. [SEMI D9-94]

point defect n : a localized crystal defect such as a lattice vacancy, interstitial atom, or substitutional impurity. [ASTM F1241] Contrast with localized light scatterer.

poly : see polycrystalline silicon.

polycrystalline adj : describes a form of semiconductor material made up of randomly oriented crystallites and containing large- angle grain boundaries, twin boundaries, or both. [SEMI M10-89 and ASTM F1241] Contrast single crystal. Also see amorphous silicon.

polycrystalline silicon (poly) n 1 : a nonporous form of silicon made up of randomly oriented crystallites or domains, including glassy or amorphous silicon layers. [ASTM F399-88] 2 : silicon formed by chemical vapor deposition from a silicon source gas or other methods and having a structure that contains large-angle grain boundaries, twin boundaries, or both. [SEMI M16-89] Also called poly and polysilicon. Contrast amorphous silicon and single crystal.

polysilicon (poly) : see polycrystalline silicon.

precipitate n 1 : within a silicon lattice, a region of silicon oxide frequently manifested as an etch pit. [ASTM F1241] Also see crystal lattice and pit. 2 : in a gallium arsenide wafer, a localized concentration of dopant that is insoluble. Precipitate is formed during crystal growth and during any process in which the temperature is sufficient to provide the necessary impurity mobility. [SEMI M10-89]

process-induced defect (PID) n : defect(s) added to the wafer as a result of a processing step. The PID wafer undergoes the same process sequence as a product wafer. PID wafer data is a closer approximation of actual process defect contributions than particles per wafer pass (PWP) wafer data. [SEMATECH]

pyramid n : a structure displaying |111| facets that appears on surfaces after epitaxial growth.

Q

NONE

R

registration n 1 : the accuracy of the relative position of all functional patterns on any reticle with the corresponding patterns of any other reticle of a given device series when the reticles are properly superimposed. [ASTM F127-84] 2 : a vector quantity defined at every point on the wafer. It is the difference, R, between the vector position, P1, of a substrate geometry and the vector position of the corresponding point, P0, in a reference grid. [SEMATECH] 3 : in the overlay capabilities of wafer steppers, a vector quantity defined at every point on the wafer. It is the difference, R, between the vector position, P1, of a substrate geometry, and the vector position of the corresponding point, P0, in a reference grid. [SEMI P18-92]

residue n : any undesirable material that remains on a substrate after any process step. [ASTM F127-84 and SEMI P3-90]

root cause n 1: in failure analysis, the fundamental incident or condition that initially caused the failure to occur.

S

saucer pits : see shallow etch pits.

saw-blade defect n 1 : on semiconductor wafers, a roughened area visible after polishing with a pattern characteristic of the saw blade travel. [ASTM F1241] Also see saw marks. 2 : a depression in the wafer surface made by the blade, which may not be visible before polishing. [SEMI M10-89]

saw exit chip n : in gallium arsenide technology, an edge fragment on a wafer broken off at the point at which the saw completed its cut of the wafer. A saw exit chip is typically straight or arc shaped, not irregular, and sometimes can be confused with the orientation flats. [SEMI M10-89] Contrast saw exit mark.

saw exit mark n : in silicon technology, a ragged edge at the periphery of a wafer consisting of numerous adjacent small adjoining edge chips resulting from saw blade exit. [ASTM F1241] Also see saw marks, saw exit chip.

saw-kerf : see scribe line.

saw marks n : on a wafer, surface irregularities in the form of a series of alternating ridges and depressions in arcs, the radii of which are the same as those of the saw blade used for slicing. [ASTM F1241] Also see saw exit mark.

scanning electron microscope (SEM) n : a device that displays an electronically scanned image of a die or wafer for examination on a screen or for transfer onto photographic film; displays a higher magnification than an optical microscope. [SEMATECH]

scanning tunneling microscope (STM) n : an instrument for producing surface images with atomic scale lateral resolution, in which a fine probe tip is raster scanned over the surface and the resulting tunneling current is monitored. [SEMATECH]

scratch n : on semiconductor wafers, a shallow groove or cut below the established plane of the surface, with a length to width ratio greater than 5:1. [ASTM F1241] Also see macroscratch, microscratch.

Scribe line n : the area on a wafer between the individual die sites reserved for cutting the wafer into individual dice.

scum n : resist residue located in a window or along the foot of patterned geometry. [SEMATECH]

scumming n : residual resist located in areas that should have been cleaned in the develop operation. [SEMATECH]

SEM : see scanning electron microscope.

semiconductor n 1: an element that has an electrical resistivity in the range between conductors (such as aluminum) and insulators (such as silicon dioxide). Integrated circuits are typically fabricated in semiconductor materials such as silicon, germanium, or gallium arsenide. [SEMATECH] 2: a material in which the electric current is made up of both negative and positive carriers (i.e., conduction electrons and holes, respectively) [JESD77].

shallow etch pits n : on a wafer, etch pits that are small and shallow in depth under high magnification greater than 200X. [ASTM F1241] Also called saucer pits. Also see haze.

short : see bridge.

silicon (Si) n : a brownish crystalline semimetal used to make the majority of semiconductor wafers. [SEMATECH]

silicon dioxide (SiO2) n : a passivation layer thermally grown or deposited on wafers. It is resistant to high temperatures. Oxygen or water vapor is used to grow silicon dioxide at temperatures above 900oC. Silicon dioxide is used as a masking layer as well as an insulator. [SEMATECH] Also called quartz. Also see glass.

silicon nitride (Si3 N4) (abbr. SiN) n : a passivation layer chemically deposited on a wafer at temperatures of between 600oC and 900oC to protect the wafer from contamination. Silicon nitride is also used as a masking layer and as an insulator. [SEMATECH]

silicon on insulator (SOI) n : a novel substrate for high-performance, low-power, and radiation-hard CMOS applications that offers process simplification, improved scalability, latch-up free and soft-error free operation, improved subthreshold slope, and drastic reduction in parasitic capacitances. At this writing, there are two manufacturing-oriented techniques to build SOI: SIMOX and bonded. Also see SIMOX and bonded. [SEMATECH]

slice : see wafer.

slip n : in semiconductor wafers, a process of plastic deformation in which one part of a crystal undergoes a shear displacement relative to another in a manner that preserves the crystallinity of each part of the material. DISCUSSION—After preferential etching, slip lines are evidenced by a pattern of one or more parallel straight lines of dislocation etch pits that do not necessarily touch each other. On |111| surface, group of lines are inclined at 60o to each other; on |100| surfaces, they are inclined at 90o to each other. [SEMI M10-89 and ASTM F1241] Also see pit.

slip line n : a step occurring at the intersection of a slip plane with the surface. [ASTM F1241]

slip plane n : the crystallographic plane on which the dislocations forming the slip move. [ASTM F1241]

small scale integration (SSI) n : the placement of between 2 and 10 active devices on a single die. [SEMATECH] Also see die.

smudge n : a dense local area of contamination usually caused by handling or fingerprints. [SEMI M1-94 and ASTM F1241]

snowball n : on a semiconductor wafer, a track with the appearance under magnification of a snowball rolled through snow. [ASTM F1241]

SOI : see silicon on insulator.

source n 1 : one of the three major components of a CMOS transistor. [SEMATECH] 2 n : a supply region that supplies principal-current charge carriers into a controlled channel [JESD77]

spike n 1 : on an epitaxial wafer surface, a tall, thin dendrite or crystalline filament that often occurs at the center or recess. [ASTM F1241] 2 : an extreme structure that has a large ratio of height-to- base width and no apparent relation to epitaxial film thickness. [SEMATECH] Also see pyramid and mound.

SSI : see small scale integration.

stacking fault n : in a crystal, a two-dimensional defect caused by a deviation from the normal stacking sequence of atoms. [ASTM F1241]

stain n 1 : a solution applied to a cross-sectioned silicon device to reveal the location of various structures. [SEMATECH] 2 : contaminant in the form of streaks that are chemical in nature and cannot be removed except through further lapping or polishing. Examples are "white" stains that are seen after chemical etching as white or brown streaks. [SEMI Materials, Vol. 3, Definitions for Semiconductor Materials] 3 : a two-dimensional, contaminating foreign substance on a component surface. [SEMATECH] Also see contamination and foreign material. 4 : in flat panel display substrates, any erosion of the surface; generally cloudy in appearance, it sometimes exhibits apparent color. [SEMI D9-94] 5 : area contamination that is chemical in nature and cannot be removed except through further lapping or polishing. [ASTM F1241]

step coverage n : the ratio of thickness of film along the walls of a step to the thickness of the film at the bottom of a step. Good step coverage reduces electromigration and high-resistance pathways. [SEMATECH]

STM : see scanning tunneling microscope.

stuck-at fault n : a fault in a manufactured circuit causing an electrical node to be stuck at a logical value of 1 or a logic value of 0, independent of the input to the circuit. [1994 National Technology Roadmap for Semiconductors]

substrate n : in the manufacture of semiconductors, a wafer that is the basis for subsequent processing operations in the fabrication of semiconductor devices or circuits. [ASTM F1241]

surface chip : see peripheral chip.

surface defects n 1 : in the manufacture of silicon on sapphire (SOS) epitaxial silicon wafers, mechanical imperfections, SiO2 residual dust, and other imperfections visible on the wafer surface. Some examples of surface defects are: dimples, pits, particulates, spots, scratches, smears, hillocks, and polycrystalline regions. [SEMI M4-88] 2 : in flat panel display substrates, a marking, tearing or single line abrasion on the glass surface. [SEMI D9-94]

T

tester pattern generation (TPG) n : the generation of a program that runs on an integrated circuit hardware tester (integrated circuit tester). The purpose of this program is to permit test vectors to be applied to the pins of the integrated circuit, and measurements made to determine the performance of the integrated circuit. [1994 National Technology Roadmap for Semiconductors] Also called tester program generation.

test pattern : see pattern, test.

test techniques n : any methods used for the expressed purpose of testing integrated circuits. Examples include built-in self test (BIST), automatic test pattern generator (ATPG), static current test (IDDQ ), and boundary scan. [1994 National Technology Roadmap for Semiconductors]

test vectors n : sequences of signals applied to the pins of an integrated circuit to determine whether the integrated circuit is performing as it was designed. [1994 National Technology Roadmap for Semiconductors]

total reflection X-ray fluorescence (TXRF) n : an analytical method usually used to characterize the level of metallic (and nonmetallic elemental) surface contamination. In TXRF, an X- ray beam excites fluorescence from the contamination that is present on a silicon surface. Since the beam is incident at grazing angles, it totally reflects from the surface, thus maximizing the signal. [SEMATECH]

trapped charges n : charges trapped either in the gate oxide or, in the case of a lightly doped drain (LDD) metal-oxide semiconductor field-effect transistor (MOSFET), in the spacer region. Trapped charges in the gate or the spacer lead to threshold voltage shift or to transconductance degradation, respectively. [SEMATECH]

TXRF : see total reflection X-ray fluorescence.

U

ULSI : see Ultra Large Scale Integration

Ultra large Scale Integration : the placement of at least 1,000,000 active devices on a single die. [JESD99]

undercutting n : the lateral etching into a substrate under a resistant coating, as at the edge of a resist image. [ASTM F127-84]

unencapsulated thermal test chip n : an unpackaged, specially designed silicon die with standard test junctions that, after mounting into a package, may be used to thermally characterize that package. This technique is useful in determining the difference between various vendors' packages and package designs. [SEMATECH]

V

Very Large Scale Integration : n the placement of at least 1000 active devices on a single die. [JESD99]

via n 1: a connection between two conducting layers above the silicon surface that is created by a different material or deposition step.

VLSI : see Very Large Scale Integration

void 1 : see dielectric void. 2 : see glass void. 3 : see metallization void.

W

wafer n : in semiconductor technology, a thin slice with parallel faces cut from a semiconductor crystal. [ASTM F1241] Also called a slice. Also see substrate.

well n : a localized n-type region on a p-type wafer or a p-type region on an n-type wafer. [SEMATECH]

X

X-ray fluorescence n 1 : the property of atoms to absorb X rays and emit light of characteristic wavelengths. [SEMATECH] 2 : a material diagnostic technique that determines the surface concentration of contaminants. [SEMATECH]

Y

NONE

Z

NONE