BAW Sensor - See Bulk Acoustic Wave Sensor.

Bead-Based Arrays - Arrays in which reactions take place on the surface of spherical miniature beads. These arrays can contain millions of individual probes, making them perhaps the most promising technology for fields such as drug discovery.

Beam Leads - Thick, strong leads deposited directly on an integrated circuit chip and used for interconnecting the circuit into the system.

Beamline - A vacuum line extending in from the source of synchrotron radiation that captures a portion of the radiation and transfers it where the radiation (like X-rays) are required.

Beam Tape - Polyimide tape supporting copper foil shaped into beam leads for TAB. Specifically designed for an in-line automation of IC package.

Behavioral Model - An efficient reduced-order model characterizing the response of a device or system to a range of input excitations.

Behind-The-Ear - See BTE.

Bimetallic Actuation - The bending movement occurring when a pile of two materials having different coefficients of thermal expansion are heated. The extent of bending is related to the temperature of the materials that are exposed and used to sense temperature rise and protect circuits from excess current flow.

BEOL (Back-end-of-line) - The processes required after the wafer fabrication for a surface micromachine, or integrated microsystem assembly. In semiconductor manufacturing, it refers to the package assembly and test stages of production. It includes burn-in and environmental test functions.

BGA (Ball Grid Array) - A style of chip package that uses an array of solder balls to achieve very high interconnect densities.

Bias Error - The inherent bias (offset) of a measurement process or (of) one of its compo­nents. See also Systematic Error.

Bias-Enhanced Nucleation Process - The agglomeration of proteins around a staring nucleus in a liquid that has dissolved proteins and is subjected to an electric field.

BiCMOS (Bipolar Complementary Metal Oxide Semiconductor) - The combination of bipolar and CMOS technologies.

Biliary Stent - Stents, made of metal or plastic tubes, designed to overcome obstruction of bile ducts.

Binary - A system of numbers using 2 as a base, in contrast to the decimal system, which uses 10 as a base. The binary system requires only two symbols, 0 and 1. The language understood by microprocessors and computers.

BioFilms - Populations or communities of microorganisms adhering to environmental surfaces. A major concern for implants like catheters, lens, and other prostheses are biofilms growing on them and shielding bacteria and other disease-causing organisms. Control of infections gets difficult due to the presence of bioFilms since it increases the concentration of antibiotics required by 100 to 1000 times the normal dose.

BioFlip - 1. A biological chip2. A BioMEMS chip packaged using Flip-Chip technology.

Bioinformatics - The discipline of storing, retrieving, analyzing, and integrating biological data.

BioMEMS - Biological MicroElectro Mechanical Systems are MEMS systems with applications for the biological/analytical chemistry market. Areas of interest include, but are not limited to, micro- and nanotechnology for drug delivery, tissue engineering, harvesting, manipulation, amplification, and sequencing of nucleic acids, proteomics, microfluidics and miniaturized total analysis systems (microTASs), biosensors, molecular assembly, nanoscale imaging, and integrated systems.

Biomimetics - The study relating to the adoption of good designs seen in living beings. For example, researchers in robotics intend to implement the principles of human and bird muscles in next-generation robotics.

Bionanotechnology - Molecular motors, biomaterials, single-molecule manipulation technologies, biochip technologies, etc. [Source: Asia Pacific nanotechnology Initiatives].

Biophotonics - The study of light given out by biological tissue. Biophotonics is used to identify diseases.

Bipolar Transistors - Transistors formed with two (n-type and p-type) semiconductor types. Such transistors are generally termed npn or pnp types.

Bipolar Junction Transistor - See BJT.

Bipolar Process - Bipolar devices are semiconductor devices in which both electrons and holes participate in the conduction process. In a typical bipolar transistor, silicon serves as a substrate and two closely coupled p-n junctions serve as contacts.

Bird's Beak - The expansion of the SiO₂ layer beneath the SiN₃ layer during local oxidation of the silicon wafer. The SiO₂ forms a structure similar to a bird's beak.

BIST (Built-In Self Test) - The ability of an IC to internally generate the sequence of test voltages required to verify its functionality.

Bit - A binary digit, the smallest unit of storage in a digital computer. It is used to represent one of the two states in the binary number system.

BJT - (Bipolar Junction Transistor)A transistor in which current is controlled by the voltage impressed across a crystal interface between p-and n-type semiconductors.

Blanket Deposition - A deposition technique on the entire surface of the wafer.

Boat - A wafer holder made from quartz or poly-crystalline silicon for use in furnace operations of semiconductor fabrication. It also may be made of Teflon for transporting wafers between processing locations.

BOE - See Buffered Oxide Etch.

Bolus - A large dose of medication given intravenously so that the desired therapeutic concentration in the blood is reached rapidly.

Bond Pads - Comparatively large metallization areas usually placed around the perimeter of the integrated circuit die to which wires or other interconnecting contacts are made.

Bond Wire - The joining of metal bond pads on an integrated circuit to a metal lead frame by using fine wires, usually of aluminum or gold.

Bonded Wafer Technology - A process in which two semiconductor wafers are bonded to form a substrate having precise features. This technology offers a high-quality, low-cost Silicon-On- Insulator (SOI) substrate capability and also a range of pre-bond processing options. The latter allows the manufacturer to optimize the total process by increasing performance while reducing cost.

Bonding - The process of connecting wires from the package leads to the chip (or die) bondingpads. Alternately, it is the process of securing a semiconductor die to a lead frame or package.

Bonding, Ball - A thermal compression-bonding technique used with gold wire. The wire end is melted to form a ball, which provides a larger area of contact than otherwise possible.

Bonding, Die - The attaching of the semiconductor die to the package substrate, with epoxy adhesives, gold eutectic or solder alloy. Also called die attachment.

Bonding, Wedge - A form of thermal compression of ultrasonic bonding used for microelectronic assembly, so named because a heated wedge is used to form the bond.

Bonding, Wire - The joining of metal bonding pads on an IC to a metal leadframe, using fine wires, usually of aluminum or gold.

Bonding Aligners - A tool which first precisely aligns patterns on two (or more) substrates, typically followed by bonding of the substrates while the patterns remain aligned.

Bonding Pads - Comparatively large metallization areas usually placed around the perimeter of the integrated circuit die to which wires or other interconnecting contacts are made.

Boolean Algebra - A logical calculus named for mathematician George Boole, using alphabetic symbols to stand for logical variables, and 0 and 1 to represent states. AND, OR, and NOT are the three basic logic operations in this algebra. NAND and NOR are combinations of the three operations.

Boron - An element used as a p-type dopant in crystal growing and in various fabrication processes, commonly used for the isolation and base diffusion in standard bipolar npn IC processing, and source/drain regions in PMOS transistors.

Boro Silicate Glass - See BSG.

Bosch Process - A silicon surface-micromachining technique developed by Robert Bosch GmbH. The process in brief: Deposit and pattern a sacrificial layer that is present on top of the surface. Polysilicon is deposited on the patterned sacrificial layer, which is then removed to form structures similar to cantilevers. Advantages include large maximum feature size (>1 mm) due to of low stress and strain gradient.

Boule - A large cylindrical silicon ingot drawn from a molten silicon melt.

Bradycardia - A medical term used to describe a slower-than-normal heart rate.

Brazing - The process of joining two or more metals by partial fusion with a layer of hard-solder alloy at high temperatures.

Breakdown - A condition when a critical level of voltage is exceeded in an insulator or semiconductor and current starts to flow.

BSG (BoroSilicate Glass) - Glass doped with boron that improves step coverage.

BTAB - See Bumped Tape Automated Bonding.

BTE (Behind-The-Ear) - A hearing instrument that fits over the ear and is coupled to the ear via an earmold. These types of hearing instruments are not popular at present.

Buffered - Refers to an acid or base solution to which a substance capable of neutralizing the acid or base has been added.

Buffered Oxide Etch (BOE) - A wet-etching technique that uses an etching solution containing hydrofluoric acid, and ammonium-fluoride. The hydrofluoric acid etches silicon-dioxide and the ammonium-fluoride raises the solution pH and protects the photoresist.

Built-In Self Test - See BIST.

Bulk Acoustic Wave (BAW) sensor - A device used in electronic nose technology. It comprises a quartz crystal coated with a chemically selective film. The crystal is configured in an oscillator circuit and typically has a base frequency of 10 MHz. When vapors from the sample interact with the coating film, some are absorbed, causing an increase in the mass of the film. This in turn leads to a decrease in the frequency of the sensor and is measured as the response.

Bulk Micromachining - The tailoring of structures by machining a wafer's interior using wet chemical techniques and differential etching rates of different crystallographic planes.

Bumped Chip - A chip from a wafer that has been processed with buffer metal(s) over the I/O pads, followed by an addition of solder or gold "bumps" to provide reflow or thermocompression bonding areas for copper-beam attachment. See TAB.

Bumped Die - A die that has solder or gold bumps formed on the bond pads.

Bumped Tape Automated Bonding (BTAB) - A bonding process where bumped dies are attached to metal leads mounted on a tape carrier. See tape automated bonding.

Bumping - The process of forming solder or gold bumps on the bond pads of a die. Electroplating or evaporation may form the bumps.

Buried Layer - A low-resistivity, diffused region placed under collector of a bipolar transistor to reduce its series resistance, commonly employed with an epitaxial structure.

Burn-In - An electrical test performed over time wherein a semiconductor device is subjected to a voltage at high temperatures. This test is an accelerated aging of devices to screen out infant mortalities. It is used on new products until yield-enhancement efforts have achieved the required yield.

C

C2D™ (Chrysler's Collision Detection) - A multiplexing network that reduces enormously the number of wires and connections required in Chrysler's automobiles.

CAD (Computer Aided Design) - Any computer program that allows the user to draw or simulate device designs (such as AutoCAD, MEMCAD, Ansys, etc.)

CAE (Computer-Aided Engineering) - A design tool similar to CAD. Traditionally, CAE has been used to describe the electrical design rather than the physical design, which was the realm of CAD, although these distinctions have blurred.

Calibration - The set of operations that establish, under specified conditions, the relation­ship between values indicated by a measuring instrument or system, or between values rep­resented by a material measure and the corresponding known (or accepted) values of a mea­surand.

Calibration Factor - A term or set of terms, calculated through calibration, by which the in­strument values are related to the corresponding known standard values. Sometimes ex­pressed as a calibration factor, calibration coefficient, or as a series of calibration factors in the form of a calibration curve.

Calorimetric Sensor Module - An array of thermopiles that measure heat generated during absorption or the adsorption of volatile materials by the sensitive coating.

Caltech Intermediate Format - See CIF.

CAM (Computer-Aided Manufacturing) - The use of algorithms for planning and controlling fabrication processes. It is a form of automation where computers communicate fabrication instructions to the machinery.

CAN (Controller Area Network) - A 250-kbit/s interface system designed to interconnect smart devices and build intelligent systems. A CAN network is used to connect different electronic control units in cars.

Cannula - A small tube for insertion into a body cavity, duct, or vessel.

Cantilever - A lever beam held down at one end, with some support near the middle, and that supports a load on the other end. Diving boards and drawbridges are cantilevers.

Capabilities - A term utilized to define the managerial assets of a firm or device and is specifically centered on husbanding the technological competencies of a firm or device.

Capacitance - The capability of storing electrical charge. It is the ratio of the charge on one of the two conductors of a capacitor to the potential difference between the conductors. Its SI Unit is aFarad (F).

Capacitance Voltage Test - See CV test.

Capacitor - A device that consists of two conductors (such as parallel metal plates) insulated from each other by a dielectric. A capacitor introduces capacitance into a circuit, stores electrical energy, blocks the flow of direct current, and permits the flow of alternating current.

Capacitor Microphone - A microphone, which is based on the conversion of sound energy to electricity by changing the capacitance of a deflecting membrane.

Carbon Nanotubes - Tiny tubes about 10,000 times thinner than a human hair and consisting of rolled up sheets of carbon hexagons. Discovered in 1991 by researchers at NEC, they have the potential for use as minuscule wires or in ultra-small electronic devices. They can be "grown" directly by chemical vapor deposition (CVD). [IBM Research Nanology "Carbon nanotubes" 2001].

CARG - See Compound Annual Rate of Growth.

Carriers - Holes or electrons available in a semi-conducting device for conduction of electric current.

Cascade Molecule - See Dendrimer.

Cassette - A vessel with slots used to hold wafers for cleaning, transporting, or processing through the fabrication processes. It is usually made of Teflon and holds up to 25 wafers. Cassettes are used to transport wafers just prior to cutting them into individual dies.

Catheter - A tube used for gaining access to one of the body's cavities. In angioplasty, a catheter provides access to the heart's arteries.

Catheterization - A procedure that involves passing a tube (catheter) through blood vessels and injecting dye to detect blockages.

Cathode - The negative electrode in an electrochemical cell at which electrons can be received from an external circuit.

CCD (Charge-Coupled Device) - A device utilizing a technique in which information is stored and transported by means of packets of minute electrical charges.

CD (Compatibility Definition) - The interface features, between a part or assembly and its next assembly that defines their capability to exist or function in the same system or environment without mutual interference.

CD - See Critical Dimension.

CD-SEM - See Critical Dimension Scanning Electron Microscope.

Cell Library - A set of computer data files which contain all the information needed to model, simulate, and layout pre-designed integrated circuit modules that can then be automatically interconnected.

CERDIP (CERamic Dual In-line Package) - A package assembled with the lead-frame sandwiched between two ceramic layers and sealed by firing a glass frit.

CERPACK (CERamic PACKage) - A CERDIP-like package with the leadframe extending out to all four sides, typically in surface-mounting format. Also known as CERPAC or CERPAK.

CERQUAD (Ceramic Quad-Flat Pack) - A packaging solution similar to CERDIP but has pins on all sides on its periphery.

Cervical Cancer - A cancer of the lowest portion of the uterus.

Channel - The conducting charge layer between source and drain of an MOS transistor that is induced by an applied gate voltage.

Characterization - The measurement of the typical behavior of instrument properties that may affect the accuracy or quality of its response or derived data products. The results of a characterization may or may not be directly used in the calibration of the instrument re­sponse, but may be used to determine its performance.

Characterization (of an IC) - The process of collecting measured electrical data about the operation of an integrated circuit component or module to enable it to be accurately modeled in a computer simulation.

Charged-Coupled Device - See CCD.

Check Valve - A valve that allows fluid to flow in only one direction.

ChemFET (Chemical Field-Effect Transistor) - A transistor with the gate electrode coated with a selective coating that absorbs volatile molecules, which changes conductivity across the transistor's gate.

Chemical Mechanical Planarization (CMP) - (also called Chemical Mechanical Polishing) The use of chemical slurry to polish a wafer's surface to eliminate topological layer effects at specific steps of the process flow in the manufacturing of semiconductors. It is an important process in BEOL. CMP technology was originally developed as a planarization tool for the manufacture of multi-level metal interconnects used in high-density integrated circuits. CMP is a critical component of the SUMMiT process enabling planar deposition in multiple-layer micro-machining processes.

Chemical Vapor Deposition (CVD) - The growth of thin solid films on a substrate as the result of thermochemical vapor-phase reactions. Also defined as a SEMICON process used to deposit material onto a wafer using chemical reactions on the wafer surface to modify the material during processing. Materials that can be deposited by CVD include polysilicon, silicon oxide, and silicon nitride.

Chip - A piece of semiconductor material, usually a section of a wafer, upon which a component or an integrated circuit is fabricated. Also called a die.

Chip Carrier - A square (or rectangular) IC package with I/O connections on four sides; connections may be leadless or leaded.

Chip Lead - The fine metallic tracks laid down on the surface of a semiconductor chip that helps it communicate with other chips.

Chip Size Packaging - An IC packaging technique that allows a single chip, irrespective of size, to be protected from handling, moisture and contaminants. The chip-sized packaged device can be used as a chip carrier and directly soldered on a printed-circuit board. CSPs are used in products where portability is important, like camcorders, hand phones, and book computers and have recently been used to package MEMS accelerometers.

Chromatography - A range of techniques for the separation of complex mixtures that rely on the differential affinities of substances for a gas or liquid mobile medium and for a stationary adsorbing medium through which the mixture passes, such as paper or gelatin.

CIC (Completely-In-the-Canal) - A hearing instrument, the smallest amplification device available, extending inwards from 1 mm to 3 mm inside the opening of the ear canal, which allows greater gain with less power due to the proximity of the receiver to the eardrum (the tympanic membrane).

CIF (Caltech Intermediate Format) - A common output format of designs drawn using a using a CAD program. These drawing eventually become masks used in photolithography.

Circuit - A combination of electrical elements connected to perform a specific function.

Circuit Layout - A tool used to convert a schematic diagram to the pattern that will be transferred to a wafer by photolithography. After verification that the circuit is complete, the schematic diagram is converted to a circuit layout based on a set of design rules for the photolithography process.

Cladding - The material surrounding the core of an optical fiber. The cladding has a lower refractive index (faster speed) to keep the light in the core. The cladding and the core make up an optical waveguide.

Clean Room - A confined area in which the humidity, temperature, and particulate matter are precisely controlled within specified units. The "class" of the clean room defines the maximum number of particles of 0.3-µm size or larger that may exist in one cubic foot of space anywhere in the designated area. For example, in a Class 1 clean room, only one particle of any kind may exist in one cubic foot of space. Newer clean rooms are typically Class 1-10, and are needed for manufacturing ICs and surface micromachines with feature sizes close to 1 µm.

Closed-Loop Feedback - An automatic control system for an operation or process in which feedback in a closed path or group of paths acts to maintain output at a desired level.

Cluster Tool - Equipment that utilizes a robot to feed a set of process chambers. They are used to perform multiple process steps on a single piece of equipment and improve process control and reduce cycle time.

CMOS - Complimentary Metal Oxide Semiconductor refers to an IC or its fabrication process that uses both p-mos and n-mos transistor technology. CMOS is finding many applications in MEMS fabrication.

CMP (Chemical Mechanical Polishing) - See Chemical Mechanical Planarization.

CNC - Computerized Numerical Control.

Cochlear Implant - A device designed to help severe to profoundly deaf individuals who gain little or no benefit from hearing aids. Cochlear implants convert acoustic sound waves into weak electric currents, which are delivered to the immediate vicinity of the auditory nerve in the inner ear or cochlea.

Cocktail Party Effect - The ability to focus on a specific voice from a variety of noises in the background. A silicon biomimetic microphone is being developed by the Cornell Nanofabrication Facility to achieve this.

Coefficient Of Diffusion - The rate at which a diffusant will diffuse into bulk material at a given temperature; measured in cm²/s.

Coefficient of Thermal Expansion (CTE) - A material property pertaining to the change in lateral dimensions of a material with respect to temperature change. CTE=(Change in length/original length) /Change in temperature; Units = ⁰C ^-1).

Collector - The region of a bipolar transistor that "collects" the emitted electrons and then passes them on through a conductor, completing the electrical circuit.

Collimated Beams - Light beams that are parallel.

Colloidal - A substance that consists of minute particles, which are too tiny to view through a simple microscope, dispersed throughout another substance and is unable to pass through a semi-permeable membrane.

Comb Drive - An electrostatic actuated MEMS device composed of inter-digitated fingers comparable to a comb. The comb has two halves, a fixed and a movable part. A potential difference applied across the two parts results in an attractive electrostatic force that pulls the combs together. Comb drives form the basis of inertial sensors and RF resonators.

Commercialization - The process that a firm designs to exploit an invention, discovery, or product for profit.

Commodity - An item that is available from multiple sources with no discernable differences in function or quality.

Compatibility Dimension - See CD.

Compatibility Drawings - Drawings of the interface features between a part or an assembly and its next assembly.

Competency - The term utilized to define the technological product and know-how assets of a firm.

Compound Annual Growth Rate (CAGR) - The year over year growth rate of an investment or market over a multiple-year period. The arithmetic definition is as follows: CAGR = (value at end of period/beginning value) ^{(1/No. of years)} - 1.

Compressive Strain - A decrease in a dimension (length, width, etc.) of a body when it is subjected to an external compressive force.

Compound Semiconductor - A semiconductor formed by the combination of Group III and Group V elements such as GaAs, GalnP, etc.

Computer Aided Design - See CAD.

Computer Aided Engineering - See CAE.

Computer Aided Manufacturing - See CAM.

Computer Modeling - The process of providing to a computer, usually in the form of mathematical equations, a precise and unambiguous description of the system under study, including the relationships between system inputs and outputs. This description is used to simulate or model the described system.

Concentration (Impurity) - The level of impurity materials as compared to "pure" semiconductor materials within the structure. The net concentration establishes the characteristic conduction pattern and other characteristics of the material.

Conditioned-Based Maintenance - A proactive equipment maintenance that is able to predict failures at an early stage. Portable inspection equipment or embedded sensors are used to derive real-time information about changes in equipment condition or operating parameters and then define the maintenance actions needed. Unlike preventive maintenance, it is not scheduled and hence reduces costs.

Conducting Polymer - Polymers in which adsorption of volatile components modulate the electrical conduction mechanism of the polymer and brings about changes in resistance.

Conductor, Electrical - A material capable of carrying (conducting) electricity. Gold is the best electrical conductor. Copper and aluminum are also popular conductors. Aluminum is the conductor most commonly used in IC fabrication.

Confidence Ranges - A confidence interval that provides a range of values around an estimate to show how precise the estimate is. The confidence level associated with the interval, usually 90%, 95%, or 99%, is the percentage of times in repeated sampling that the intervals will contain then true value of the unknown parameter.

Configuration Management - A process for managing physical configurations and physical processes through documents, records, and data.

Conformal - A property of films like photoresists, deposited metal etc. that are coated on a wafer. If the thickness of the film is the same throughout the surface irrespective of the contour, the film is said to be conformal.

Contact Aligner - An optical system that uses contact printing to expose a wafer.

Contact Printing - Exposure of a wafer by passing light through a mask that is in direct contact with the photoresist coated wafer. Chrome working plates are most commonly used due to their longer life, but emulsion-working plates can be used to prevent damage to the wafer.

Contacts - The regions of exposed silicon that are covered during the metallization process to provide electrical access to individual devices.

Contamination - A general term used to describe unwanted material or foreign matter that adversely affects the electrical characteristics of a semiconductor wafer.

Continuous Innovation - Incremental product improvements that occur within the existing milieu. These innovations utilize existing knowledge in existing markets and extend current technology product platform schemas.

Continuum Modeling - The modeling of components based on continuum materials properties such as Young's Modulus, hardness, ductility, etc.

Contour Maps - Plots of measured data related to a wafer on a screen depicting resistance per square deviations with respect to a mean value.

Contrast - The degree of sharpness of the transition of exposed to non-exposed parts in photoresists.

Controller Area Network - See CAN.

Control Parameter Metrics - A control parameter is a measurement taken for controlling an in-line process or as a test on a product.

Core - The central region of an optical fiber through which light is transmitted. It has a refractive index different from the surrounding cladding.

Core Competence - A term that has become ubiquitous and can mean many things. They include what a firm does best, what an individual does best, the industry standard technology bundles required, and many others. Here, we utilize the term to mean a unique set of technology know-how and production skills that enables a firm to be ahead of its competitors.

Cores - A complex, pre-designed functional module (e. g. a digital signal processor) that is integrated within a larger chip.

Coriolis Effect - The noticeable deflection of moving objects on the surface of a rotating body such as the Earth. The deflection is rightward in the northern hemisphere and leftward in the southern hemisphere.

Coronary Arteries - Arteries that supply freshly oxygenated blood to the heart. Insufficient oxygen reaching the heart muscle via the coronary arteries may cause angina, heart attack (myocardial infarction), or even death.

Coronary Artery Disease - Arteriosclerosis of the coronary arteries.

Coronary Stent - A stent used to open up a blocked coronary artery (a blood vessel that carries blood from the heart to the rest of the body). After implantation, the coronary stent becomes a permanent implant to hold the artery open and prevent it from closing back down.

Correction - The value which, when added algebraically to the uncorrected result of a measure­ment, compensates for an assumed systematic error. The correction is equal to the assumed systematic error, but of opposite sign. Since the systematic error cannot be known exactly, the correction value is subject to uncertainty.

Cost Leadership Strategy - A strategy of producing a product of average function and quality, produced at a lower-than-industry average cost.

Cost Structure - The mix of variable and fixed costs faced by a firm in producing a product.

Coulomb - [C] A measure of electrical charge. One Coulomb is the electric charge equal to the quantity of electricity transferred by a current of one ampere in one second.

Covalent Bond - A chemical bond between atoms such that they share electrons.

Creative Destruction - Creative destruction occurs in an industry when a new technology or product paradigm replaces the old. The industry becomes redefined and uses a new technology trajectory. This has occurred in microsystems when MEMS-based accelerometers eclipsed the mini-electro-mechanical systems developed for air-bag exploders in passenger cars.

Critical Dimension (CD) - The smallest width or space of fabricated devices on a wafer (usually width of the gate). Critical dimensions are measured on some or all wafers following any photolithography or etching process.

Critical Dimension Scanning Electron Microscope (CD-SEM) - A device that measures the critical dimension of an IC or MEMS device.

Cross-Calibration - The process of assessing the relative accuracy and precision of re­sponse of two or more instruments. A cross-calibration would provide the calibration and/or correction factors necessary to compare data from different instruments looking at the same target. Ideally, simultaneous viewing of the same working stan­dards or target would do this.

Cross-Connect Switching - An optical switching technique that permits light signals to be differentiated by wavelength and routed across the network to a destination, as light, and not to be converted to electrical signals. Using a cross-connect switch, vast amounts of traffic data can be bundled and sent over pre-set routes.

Crosstalk - Signal interference between adjacent channels that carry current usually due to coupling between them in some element, e.g., ICs, power supplies, adjacent cables, and adjacent teleme­try channels.

Crystal Orientation - The relationship of wafer surface to the crystal facets at which the crystal is sliced. Each crystal orientation has a direct effect on device characteristics.

Crystal Structure - The style in which atoms or ions are arranged. It is defined in terms of the atom positions within the unit cell.

Crystallography - The science and classification of crystals, particularly the semiconductor material employed to fabricate transistors and integrated circuits.

CTE - See Coefficient of Thermal Expansion.

Current - The flow of electrons. Usually measured in Amperes (amp or A).

Cutoff - . Condition in a diode, transistor, or an electrical circuit in which there's no current flow.

CV Test - Capacitance Voltage test. A technique used to characterize the amount of active defects and mobile contaminants in a gate oxide. It's also used to find the dopant profile of a pn junction.

CVD - See Chemical Vapor Deposition.

Cyclization - A chemical reaction that causes parts of a molecule to join so that a ring of atoms is formed within the molecule.

Czochralski Method - The most common single-crystalline silicon growth technique used by industry. It uses a seed crystal introduced into a container of molten silicon liquid, which is pulled to form a solid single-crystalline silicon ingot.

D

Damascene - A processing technique used in semiconductor processing to achieve copper interconnects. By this process, a metal conductor pattern is entrenched in an etched dielectric film on a silicon substrate and a planar interconnect layer is obtained.

Darkfield Mask - A lithographic mask where clear glass will define electrical components like transistors on wafers. Most of the mask is covered with chrome.

DARPA> (Defense Advanced Research Projects Agency) - A research and development organization that is a part of the U.S. Govt.'s Department of Defense (DoD). It funded MEMS research when microsystems/MEMS was in its infancy. DARPA looks at research both from a military and commercial perspective though it concentrates on the former.

DC (Direct Current) - The external, constant-voltage, single-polarity electrical power supplied to an IC.

DCA (Direct Chip Attach) - An IC packaging technique where the chip is attached upside down directly on a substrate through epoxy attach and wirebonding.

Dead Band - The range through which a stimulus can be varied without producing a change in the response of a measuring instrument. The inherent dead band is sometimes de­liberately increased to reduce unwanted change in the response for small changes in the stim­ulus.

Decibel (dB) - Defined as 20 times the logarithm (base 10) of the intensity ratio between two signals. It is a unit to express a comparative difference in intensity of electrical or acoustical signals, usually the latter. E.g., 60 dB refers to an intensity ratio of 1000 between the two signals.

Decimation - The process of eliminating data frequencies in digital data used with digital filtering to minimize aliasing.

Decision Risk - The probability of making an incorrect decision.

Deep Reactive Ion Etching - See DRIE.

Deep Sub-Micron - See DSM.

Deep Ultra Violet (DUV) - Electromagnetic waves with a wavelength between 100 to 300 nanometers (100-300 x 10^-9 m).The IC industry is using DUV lasers to obtain the 0.13-µm technology node.

Defect - An imperfection in the surface or substrate of a silicon wafer, which causes one or more chips to malfunction. A defect in a silicon crystal refers to the presence of a break in the periodicity of arrangement of atoms in the crystal lattice.

Defect Density - The number of defects per unit area of wafer surface.

Defense Advance Research Projects Agency - See DARPA.

Degree of Planarity (DP) - The flatness of the wafer surface at a particular step height location relative to the initial step height.

Deionized Water - Water from which the majority of ions and particle contamination have been removed, which is ideal for semiconductor fabrication. This term is replaced by the term Ultra Pure Water (UPW).

Demultiplex - To separate a multiplexed signal into its component parts. See multiplex.

Dendrimer - A synthetically constructed strand of molecules built with nanoscale precision. It is similar to a polymer except that it is not randomly ordered. Chemicals can be attached to it to detect and cure diseases.

Dendritic - A structure that branches repeatedly, i.e. tree-like.

Dense Wavelength-Division Multiplexing - See DWDM.

Density - A property of a material defined as the ratio of mass to volume of a sample.

Deoxyribonueleic acid (DNA) - A nucleic acid that carries genetic information in the cell. DNA consists of two long chains of nucleotides warped into a double helix and coupled by hydrogen bonds. The sequence of nucleotides in the DNA determines individual hereditary characteristics. DNA is responsible for all protein synthesis and handling genetic information in living beings.

Depletion Device - A type of MOSFET, which is "on" when no input signal is present.

Depletion-Mode Transistor - A MOSFET that is on even though there is no external exciting voltage.Depleting the channel of carriers turns it off.

Depletion Region - That area at a p-n junction which, when reverse-biased, is swept clear of free charges.

Deposition - The procedure in which materials are deposited onto a substrate. Usually refers to thin conducting or insulating films used to form MOS gates, capacitors, thin-film resistors, and the interconnect system for an IC. Electro-deposition is used in the LIGA process to deposit metal plating onto the wafer substrate.

Depth Of Focus (DOF) - The range of distances between a lens and image plane for which the image formed by the lens at a given setting is clearly focused. In current IC processing technology, the depth of focus offered by high-resolution lithographic tools is limited to around 1 µm. Due to depth-of-focus limitations, planarization techniques have to be adopted if the mask pattern is to be accurately transferred to the silicon wafer.

Derived Units - Units expressed algebraically in terms of base units (of a system of measure) by the mathematical symbols of multiplication and division. Because the system is coherent, the product or quotient of any two quantities is the unit of the resulting quantity.

Descum - A plasma etch operation following development that removes photoresist from areas of the wafer exposed to light.

Design For Manufacturing - See DFM.

Design For Test (DFT) - Design strategies adopted in early chip design that considers the testability of the device after production. The designer will have to sacrifice device compactness and allow the incorporation of new structures to make failure analysis and testing easier. This could include adding special circuits as part of an IC to aid in testing fabricated chips.

Design Intent - The information and knowledge, which collectively forms the technical basis of a product's design. Fundamentally it consists of design input, constraints, concepts, and requirements, which are required to ensure that customer requirements are satisfied.

Design Kit - A collection of technical information, software, and computer data files that enable the designer to model, simulate, and layout ICs using a specific technology (e. g. 0.8-µm CMOS).

Design Layout and Validation - The determination by review of quality evidence that a particular design layout has met specified requirements.

Design Rule Check - Commonly referred to as DRC, it is the process of checking for violations of the design rules (width, spacing, overlap of geometry, materials) for a specific technology.Rules are established through repeated part fabrication. It is an operation carried out by a CAD tool, which compares the dimensions, separations, overlaps, etc. of a chip layout to the minimum and maximum dimensions specified by the design rules for a particular process.

Design Rules - Rules for design of a device, established by repeated part fabrication, or materials testing, and includes minimum feature widths, minimum feature spacing, feature overlap dimensions, etch release hole spacing, material characteristics, etc.

Design Space - The boundaries that constrain a design.

Desorption - The discharge of by-products due to reactions on the wafer.

Detector - A device or substance that indicates the presence of a particular quantity with­out necessarily providing its value. In some cases, an indication may be produced only when the value of the quantity reaches a given threshold. e.g. halogen leak detector, temperature-sensitive paint.

Develop - The third step in the photolithography process, during which chemicals are applied on coated and aligned wafers to remove areas of exposed photo resist, leaving the wafer with a photo resist pattern.

Devitrification - . The process in which a non-crystalline material (glass) changes to a crystalline solid.

DFM (Design For Manufacturability) - Statistical information on manufacturing process characteristics used to ensure that the device design falls within the parameters of normal manufacturing variances for each process element. This allows the designer to center the design for maximum performance and enhances yields, thereby reducing cost.

DFT - See Design For Test.

Diborane (B₂H₆ ) - A highly toxic and combustible gas used as a boron source for ion implantation and CVD.

Die Array - or Matrix - The grid pattern that appears on the wafer surface due to marking of die patterns on the wafer.

Die Attach - The attachment of the die to the leadframe or substrate, usually by epoxy.

Die Bonding - See Bonding, Die.

Die Yield - The ratio of the number of good die by the number of dies tested. Measured on a per-wafer or per-lot basis.

Die - Chip cut from a larger wafer before it is packaged.

Die-by-Die Alignment - An alignment method used by pho­tolithography steppers that align each die on the wafer to the reti­cle, one die at a time.

Dielectric - A material typically used as an insulator that contains few (if any) free electrons, has low electrical conductivity and supports electrostatic stresses.

Differentiation Strategy - A strategy of producing a high-function and quality product at approximately industry average cost.

Diffraction - The phenomenon of light that occurs when light passing through a narrow aperture bends when it passes around an edge.

Diffusant - See Dopant.

Diffusion - A high-temperature process by which selected chemicals (dopants) enter the crystalline structure of semiconductor materials to change the electrical characteristics at desired locations. This process takes place in a diffusion furnace.

Digital - A method of representing information in an electrical circuit by switching the current on or off.

Digital Circuit - A circuit that operates like a switch and can form logical functions. It's used in computers or similar logic-based equipment.

Digital Cross-Connect - See DXC.

Digital Light Processor (DLP) - A technology developed by Texas Instruments that enables analog-digital conversion necessary to connect a computer to video devices. DLP projectors are based on the combination of the DMD and the processing techniques to make extremely bright and sharp pictures. An electrostatic driven MEMS mirror represents each image pixel in a large array. DLP technology is widely licensed to conference display projector manufacturers such as Proxima and InFocus.

Digital Micromirror Device - See DMD.

Digital Signal Processing - See DSP.

Diluent - An inert gas like argon, used along with reactant gases to maintain the preferred reaction rate.

Dimple - A small feature or bump, typically a raised square on the surface of a MEMS device. Dimples can be used as mechanical stops. e.g. to control the touchdown in a high-aspect-ratio device.

Diode - A two-terminal device that allows current to flow only in one direction. A diode is present at the intersection (junction) of a p-type and an n-type semiconductor.

DIP (Dual In-Line Package). - A common type of IC package; circuit leads or pins extend symmetrically outward and downward from opposite sides of the rectangular package body.

Dipole - An electric field created by two opposite charges of equal magnitude that are separated by a small distance.

Direct Chip Approach - See DCA.

Direct Current (DC) - The flow of electrons that only goes in one direction.

Direct Method of Measurement - A method of measurement in which the value of the measurand is obtained directly, rather than by the measurement of other quantities functionally related to the measurand. e.g. measurement of a length using a grad­uated rule.

Direct Simulation Monte Carlo - See DSMC.

Direct Wafer Bonding - Bonding wafers not using an intermediate adhesive material.

Discontinuous Innovation - Fundamental and far-reaching product changes that require the users or producers to change. Often discontinuous innovations are first used in an industry setting by lead user groups that are not being satisfied by the industries' current product offerings. Established companies often find it harder to cope with discontinuous innovations than with continuous innovations.

Discrete Device - A semiconductor device containing only one active element, such as a transistor or a diode.

Discrimination - See Resolution

Discrimination Threshold - The smallest change in a stimulus that produces a percepti­ble change in the response of a measuring instrument. The discrimination threshold may depend on, for example, noise (internal or external), friction, damping, inertia, or quanti­zation. E.g., if the smallest change in a load that produces a perceptible displacement of the pointer of a balance is 90 mg, then the discrimination threshold of the balance is 90 mg.

Disklike Liquid Crystal - See DLC.

Disruptive Technology - Those technologies that have redefined the technology/product paradigm in an existing application area and have created the basis for a new industry. They are only acknowledged in hindsight and are often called typhoon technologies, creative destroyers or by other such anachronisms. We often use the term nascent disruptive technologies to identify technologies that have this potential not yet realized.

Dislocation - A crystal defect due to a discontinuity in the crystal lattice structure.

Dissolution Rate - The rate at which a developer dissolves the photoresist. It depends on developer concentration and the device feature size being patterned.

Dissolved Wafer Process - A wet bulk micromachining process developed by the University of Michigan that can be used to create MEMS inertial devices and sensors. It involves an anodic bond of a silicon sensor to a glass substrate.

DLC (Disklike Liquid Crystal) Disk-shaped molecules stacked like coins over a sensor's surface. The sensor's interaction with gas molecules disrupts the stacks resulting in change in resistance.

DLP - See Digital Light Processor.

DMD^TM (Digital Micromirror Device) - Thousands of microscopic mirrors fabricated on hinges on top of an SRAM. Each mirror is able to switch or move into two states, "on" or "off," and controls an individual pixel of light.

DMOS - Double-Diffused MOS. Also called VMOS (differing from V-groove MOS), for its vertical flow of current through the substrate.

DNA - See Deoxyribonucleic acid.

Donor - An impurity that can make a semiconductor n-type by donating extra "free" electrons to the conductive band. The free electrons are carriers of negative charges. See also Acceptor.

Dopant - (also Diffusant) Dopants are the materials used to change the characteristics of a semiconductor crystal.

Dopant Profile - A plot showing the amount of dopants added or distributed in a wafer at various depths.

Doping - Atoms with one less electron than silicon (such as boron), or one more electron than silicon (such as phosphorous), introduced into the area exposed by the etch process to alter the electrical character of the silicon. These areas are called p-type (boron) or n-type (phosphorous) to reflect their conducting characteristics.

Dose (Q) - The number of ions of an ion-implantation beam per unit area of wafer surface. Units are ions /cm² .

Double-Diffused Devices - Transistors in which two p-n junctions are formed in the semiconductor wafer by gaseous diffusion of both p-type and n-type impurities. See also planar devices for definitions of p- and n-type semiconductors.

Double-Diffused MOS - See DMOS.

Downstream Reactor - A reactor that ensures reduction of damage to the wafer surface by ion bombardment during dry plasma etching, by locating the wafer away from the plasma source.

Downtime - The time a piece of equipment is not available for use in production, since it is broken or undergoing maintenance.

DP - See Degree of Planarity.

Drain - The working current terminal (at one end of the channel in an FET) that is the drain for holes or free electrons from the channel. It corresponds to the collector of a bipolar transistor.

DRAM (Dynamic Random Access Memory) - Memory circuits that require regular refreshing of the data stored in each memory cell. The circuits are more compact than static RAM but do not retain data when the refresh signal (clock) or power is turned off.

DRC - See Design Rules Check.

DRIE (Deep Reactive Ion Etching) - An etching technique that uses plasma to obtain high-aspect-ratio structures or deep features.

Drift - The slow variation with time of a metrological characteristic of a measuring instru­ment.

Drive-In - The second part of a two-part diffusion. It is the part of the operation in which the diffusant deposited during predeposition is diffused further into the wafer to achieve the desired impurity profile.

Dry Etching - Processes based on chemically aggressive gases (e.g. RIE), plasma, and particle-bombardment.

Dry-In/Dry-Out - : A chemical mechanical planarization approach that eliminates the generation of liquid vapors. Room-temperature processing methods achieve dry-in/dry-out.

Dry Strip - A post ion-implantation dry photoresist removal process that turns photoresist chemicals into ash. The dry removal process is accomplished using a fluorine-based gas, which forms a microwave-generated plasma that converts the photoresist into ash.

DSM - (Deep Sub-Micron) Fabrication processes using dimensions less than 0.5 µm or 0.35 µm are often described as DSM. Any activities aimed at using these processes are deemed DSM, for example, a DSM digital design flow.

DSMC (Direct Simulation Monte Carlo - ) - A numerical technique for modeling gas flows. Every set of particles is given a position, velocity, an internal energy, etc.

DSP (Digital Signal Processing) - The manipulation of information that has been numerically coded using a digital circuit. Analog data (signals) are first converted to digital form by an analog-to-digital converter (ADC), then processed using digital circuits, then converted back to analog form by a digital to analog converter (DAC).

Dual-In-Line Package - See DIP.

Ductility - A measure of a material's ability to be drawn into wire or hammered thin, before it gets fractured.

DUV - See Deep Ultra Violet.

DWDM (Dense Wavelength Division Multiplexing) - A technology that enables data from different sources to be put together on a single optical fiber. Each signal is carried simultaneously on its own distinct wavelength. Using DWDM, up to 80 or more separate wavelengths or channels of data can be transmitted on a single optical fiber which would be able to deliver 200 billion bits a second.

DXC ( Digital Cross-Connect) - A telecommunication network device that is used to arrange lower-level digital signals among higher-level digital bit streams.

DXF (AutoDEsk Drawing eXchange Format) - A drawing format commonly used to transfer layout information between EDA tools and by the foundry to generate fabrications masks.

Dynamic Measurement - The determination of the instantaneous value of a quantity and, where appropriate, its variation with time. The qualifier "dynamic" applies to the mea­surand and not to the method of measurement.

Dynamic RAM (Random Access Memory) - See DRAM.

E

e-beam (or Electron Beam) - Refers to a machine that produces a stream of electrons (electron beams) that can be used to expose resists sensitive to such beams. It can be used to expose photosensitive film in the production of IC masks (photo-masks), or the circuit elements themselves.

Echelette Grating - A coarse diffraction grating of 100-200 lines/mm (used to separate light of different wavelength) that enables resolutions of 1-2 Angstroms.

ECL (Emitter-Coupled Logic) - A form of current-mode logic in which the output is available from an emitter-follower output stage.

Economies of Scale - A decrease in per-unit costs as production volume increases. This effect is driven by fixed costs.

ECR (Electron Cyclotron Resonance) - Providing energy to electrons by the use of RF energy at the electron cyclotron resonance frequency.

EDA (Electronic Design Automation) - A term used for activities or facilities that involve software design aids used in chip design, or the industry sector making the aids.

EDM (Electro Discharge Machining) - Milling using electric sparks.

EDP (Ethylene Diamine Pyrocatechol) - A silicon etchant, like KOH or TMAH, but highly toxic.

EEPROM or E²PROM (Electrically-Erasable PROM) - Similar to ROM, but with the capability of selective erasure through special electrical stimulus. Sometimes termed EEROM.

Elastic Modulus - See Young's Modulus.

Elastomers - Polymers having the elastic properties of rubber.

Electrical Breakdown - See breakdown.

Electrically-Erasable PROM - See EEPROM.

Electrical Overstress - See EOS.

Electro-Static Discharge - See ESD.

Electrochemical Etch-Stop - A microfabrication wet-etching technique that enables the manufacture of single-crystalline silicon micro diaphragms. The process in brief: A wafer with a known doping profile is ion-implanted to form a well-designed p-n junction at the boundary between the varyingly doped areas of a silicon wafer. The wafer is put in a potassium-hydroxide etchant bath and a potential is applied to the p-n junction. The process is designed such that the silicon is etched until the formation of oxide that inhibits further etching when it reaches the p-n junction.

Electro Discharge Machining - See EDM.

Electroluminescence - The emission of visible light by a p-n junction when a forward-biased voltage is applied across it. It also refers to the emission of light caused by an electric discharge in a gas.

Electrolyte - A substance that when dissolved in a suitable solvent or when fused can conduct electricity.

Electromagnetic Interference (EMI) - External electromagnetic waves affecting the performance of electronic devices. The most common source is solar flares. Sensitive electronic devices have to be designed considering EMI effects.

Electromechanical - Pertaining to a mechanical device, system, or process that is electrostatically or electromagnetically actuated or controlled.

Electromigration - The movement of atoms in a metal interconnect line due to collisions by conduction electrons. The metal atoms migrate in the direction of current flow and can create voids in interconnect metal lines leading to failure of the IC. The addition of copper to aluminum reduces electromigration.

Electron - An elementary charged atomic particle that carries a negative charge of electricity.

Electron Beam - See e-beam.

Electron Cyclotron Resonance - See ECR.

Electron Design Automation - See EDA.

Electrophoresis - The migration of oppositely charged colloidal particles or molecules in opposite directions through a solution under the influence of an external electric field. This process can be used to separate molecules composed of ions of opposite charges. The rate of movement of these molecules reflects its composition.

Electroplate - Deposition of metals using an electric current and an electrolyte solution.

Electro Static Discharge - See ESD.

Electrostatic Force - Mechanical force caused by a voltage between two electrodes.

EM - Electro-Magnetic.

Embolization - The process or state in which a blood vessel or organ is obstructed by the lodging of a material mass (as an embolus).

Embolus - An abnormal particle like an air bubble, circulating in the blood. Embolic coils can be released using a microgripper into the brain during aneurysms.

EMI - See Electromagnetic Interference.

Emitter-Coupled Logic - See ECL.

Emitter Diffusion - The diffusion during which the emitters of the transistors are formed.

Emitter - The region of a bipolar transistor that serves as a source or input end for carriers.

Emulsion - A photoplate covered with a suspension of a salt of silver in gelatin or collodion, which is exposed and developed to produce a photomask.

End-Effector - A tool or instrument connected to the tip of a robot arm. Every end-effector has its own structure and is programmed according to the required task(s).

Engineering Units - A set of defined units commonly used by an engineer in a specific field to express a measurand. The units should be expressed in terms of a recognized system of units, preferably SI units.

Enhancement Device - A type of MOSFET that requires a control signal input to turn on the device. The device is "off" when no input signal is present.

Environmental Variables - Variable physical properties in the environment of the in­strument or target (such as temperature, particulate and electromagnetic radiation, vacuum, and vibration) that may affect the result of a measurement. The sensor does not mea­sure an environmental variable; it measures an observable.

Enzymes - Molecules found in nature or man-made, which speed up chemical reactions.

EOS (Electrical Overstress) - A transient or steady state electrical condition that exceeds the specifications and/or capabilities of a device. Both the magnitude and duration of an EOS event can vary. Examples of mild EOSs are oxide ruptures and junction damage with signs of visual stress. Severe EOS may include massive vaporization of bond wires or aluminum interconnects and carbonizing of plastic packages.

Epi - Short for epitaxy. The controlled growth, atom by atom, of a layer of crystalline semiconductor material on a suitable substrate.

Epipoly - Epitaxially deposited polysilicon.

Epitaxial Layer, Epitaxy - See Epi.

Epon SU-8 - See SU-8.

Epoxy - A family of thermosetting resins used in the packaging of semiconductor devices. Epoxies form a chemical bond to many metal surfaces.

EPROM (Eraseable Programmable Read-Only Memory) - Similar to ROM, but enables the user to erase stored information. Normally refers to a memory device whose contents may be erased by exposure to ultraviolet light.

Error - The difference between the result of a measurement and the value of the measurand.

ESD (Electro Static Discharge) - A static buildup of electrons that is then discharged. The magnitude of ESD can vary widely, but the duration of a pulse is usually very short. An ESD event can result in junction failure, contact damage, filamentation, oxide thermal damage, oxide breakdown, charge injection and fusing (opening) of interconnects.

EST - See Expressed Sequence Tags.

Etching - The removal of portions of a layer of conductive material from a usually insulating etchingbase through chemical or electrolytic means. In wet etching, the material is dissolved when immersed in a chemical solution. In dry etching, the material is sputtered or dissolved using reactive ions or a vapor-phase etchant.

Etch Pit - Microscopic cavities that can be formed on the surface of a crystal if discontinuities in the normal lattice structure intersects its surface. Etch pits will form if atomic impurities in the crystal get concentrated at these discontinuities due to thermal treatment, and the crystal specimen is subsequently chemically etched.

Etch Profile - A representation that illustrates the shape of the sidewall of the etched structure.

Etch Stop - A technique of stopping the etching at well-defined locations, e.g. at silicon-insulator interfaces or p-n junctions in semiconductors.

Etchback Planarization - A technique that involves bulk removal of raised material during a planarization process. A surface of SiO₂ can be made planar, by an etchback planarization process by spinning a thick photoresist on the SiO₂ and etching both the photoresist and SiO₂ until the required thickness of SiO₂ is obtained. This technique is used to fill voids and low areas on the surface.

Ethylene Diamine Pyrocatechol - See EDP.

Eutectic - A particular composition of the alloy having the lowest melting point and is lower than the melting point of its constituents. Its applications include high-quality soldering in surface-mount chips since eutectic alloys have a fixed melting point unlike other alloys, which have a range of melting-point temperatures.

Eutectic Attach - An obsolete method of connecting a chip to a lead-frame by depositing gold on the backside of the chip to alloy to the substrate.

Eutectic Bonding - A wafer-level packaging technique involving the deposition of intermediate metallic and glass films prior to the bond. The wafer is heated to the eutectic point, which is the lowest melting temperature in a two-component phase diagram where there is little or no solid solubility between the components. An alloy is then formed by solid-liquid inter-diffusion at their contact interface and is followed by solidification upon cooling.

Evaporation - A method for depositing metal on wafers by heating a material until it vaporizes and deposits on the wafers.

Excimer laser - A laser that uses chemicals like ArF and KrF (called excimers or excited dimers) that generates light having wavelengths of less than 200 nm. Used as a common source of ultra-violet rays in semiconductor lithographic tools.

Exposure - Subjecting a sensitive chemical to light or other electromagnetic energy.

Expressed Sequence Tags (EST) - Genetic sequences that are expressed as mRNA but have no known identity or function. ESTs do not represent genes.

F

Fab - The informal name for a chip manufacturer's fabrication plant where ICs or MEMS devices are made. SEMICON industry term for a foundry.

Fabless - A characteristic of certain semiconductor companies that contract with outsource foundries for their wafer fabrication requirements.

Fabrication - The process of creating ICs on the surface of wafers. It refers to only the front-end processing of devices in semicon­ductor wafers and does not include the back-end processing like assembly and packaging.

Face-Centered Cubic (FCC) - The crystal structure associated with semiconductors (Si, Ge, GaAs) and metals. In FCC, atoms are found at all 8 corners of a cube and at the center of each face.

Failure Analysis - An orderly procedure for determining that a device has failed. The results are frequently useful for enhancing the reliability of subsequent products.

Failure In Time - See FIT.

Failure Rate - A rate of failure per unit time, for example, 3 failures per 164 hours or 1 failure per day, etc. Semiconductors are usually measured in failures per 1000 hours.

Farad - The unit of capacitance. It is equal to the capacitance of a capacitor between whose plates there appears a potential of one volt when it is charged by one coulomb of electricity.

Fault Models - Software rules to identify differ­ent types of failures during electrical testing.

Fault Tree - The relationship between a "top event" (a critical functional failure in the system operation) and a combination of component faults.

FCC - See Face-Centered Cubic.

FEA (Finite-Element Analysis) - A simulation procedure for analyzing multiphysics behavior.

Feature Size - See Critical Dimension.

FED (Field-Emission Display) - A display technology using electron emitters, placed in a grid, and individually controlled by cathodes. It consumes less power than conventional cathode-ray tubes and improves image quality.

FEM (Finite-Element Method) - A method of computationally analyzing mechanical components.

Femto - A prefix meaning one-quadrillionth ( 1 x 10^-15 ). Its symbol is f.

Ferroelectric - A property of a particular material that determines its polarization in one direction or the other, or reversed, if a positive or negative electric field is applied, e.g. lead zirconate titanate (PZT).

FEOL - See Front-End Of Line.

FIB (Focused Ion Beam) A finely focused ion beam (often Ga⁺) used for imaging and milling. The most-used tool in failure analysis.

Fiber Bragg Grating - An optical fiber that has periodic variations in the index of refraction lengthwise along the fiber. The period of the index modulation can be designed to cause deflection of light at a specific wavelength, and functions as an optical filter.

Fiber-Optic (FO) Sensor - Conventional optical fiber layered with fluorescent coating that interacts with odorant molecules. The coating adsorbs an optical pulse.

Fiber Optics - The conduction of light waves through certain materials across long distances. It demonstrates total internal reflection by combining like materials of differing indices of refraction.

Field-Effect Transistor (FET) - A solid-state device in which current is controlled between the source and drain terminals by voltage applied to a non-conducting gate terminal.

Field-Emission Display - See FED.

Field Oxide - A relatively thick layer of silicon dioxide (on the order of µms) that covers the surface of an IC between active components and acts as an insulating layer. This oxide is porous and prevents induced charge in the wafer surface. See also Gate Oxide.

Field-Programmable Gate Array - See FPGA.

Filter - A circuit that inhibits the transmission of frequencies. A low-pass filter allows the transmission of low frequencies, while a high-pass filter allows the transmission of high frequencies.

Final Assembly and Packaging - The assembly and packaging of the IC chip. Also known as first-level packaging.

Finite-Element Analysis, Finite-Element Method - See FEA, FEM.

First Interlayer Dielectric (TLD-I) - The dielectric between the wafer and the first interconnect metal layer.

First-Level Packaging - The assembly and packaging of the IC chip. Also known as final assembly and packaging.

First Production - The period when the manufacture of a product according to product specifications is initiated and quality control and inspection procedures are implemented. This culminates in an authorization that releases material for specified uses.

FIT (Failure In Time) - A measure of failure rate in 10⁹ device hours; e.g. 1 FIT = 1 failure in 10⁹ device hours.

Fixed Cost - A cost that does not vary with the level of output. The fixed cost per unit decreases as production levels increase.

Fixed-Fixed Beam - A beam that is supported at both of its ends.

FL (Fuzzy Logic) - A method to mathematically represent uncertainty and ambiguity and provide formalized tools to deal with data whose boundaries are not sharply defined (i.e. are fuzzy). Some PalmTops use fuzzy logic to recognize handwriting.

Flat Pack - A ceramic surface-mounted hermetic package. Very popular for military applications because of its small size, but characterized by lead and package seal fragility, poor structural strength, excessive gold, and loose-particle problems.

Flats - The flat portion on the periphery of a circular wafer that identifies the crystal orientation.

Flip Chip - A packaging technique introduced by IBM, where the chip is attached to the plastic or ceramic substrate facedown without using the cumbersome peripheral wire bonding. A grid of solder balls on the surface of the active area of the die is joined directly to a corresponding set of solder pads on the substrate. An IC designed for facedown mounting, is attached by controlled-collapse solder pillars on I/O pads of the device.

Flip-Flop - An electrical circuit having two stable states of on or off. A basic logic circuit component.

Float-Zone Crystal Growth - A crystal-growth method that produces a single-crystalline silicon ingot that has lower oxygen content and is of higher purity than Czochralski growth. It is obtained by selectively heating the silicon ingot. This technique is not adopted due to difficulty in obtaining accurate doping concentrations.

Fluorosilicate Glass (FSG) - Glass (SiO₂) in which fluorine is added to reduce the dielectric constant of glass. It is used in multilevel metallization.

Focal Length - The distance from the center of the lens to the focal point.

Focal Point - A point along the axis of the lens where light rays refract and converge.

Focus - A condition where most of the individual rays of radiated energy are made to converge together into a single point.

Focused Ion Beam - See FIB.

Footprint - Floor space area occupied by certain equipment in the cleanroom.

Forward Bias - A p-n junction is said to be under forward bias if an external voltage is applied across a junction such that the p side is positive with respect to the n sideand current flows from the p side to the n side.

Foundry - Semiconductor fabrication facilities, which house a given set of equipment to prototype or manufacture IC wafers and chips or MEMS devices. It's usually owned by private contractors who are not associated with any individual company. Foundries specialize in certain devices or processes.

FOUP - See Front-Opening Unified Pod.

Four-Point Probe - A metrology tool used to measure sheet resistance. It forces a current through the two probes and measures the resulting voltage drop across the other two probes.

FPGA (Field-Programmable Gate Array) - An IC fabrication technology in which pre-fabricated circuit modules are electrically configured by the user to meet specific design requirements on a chip-by-chip basis.

Frenkel Defect - A defect found when an atom leaves its crystal lattice site and takes up position in between two layers of atoms. It can migrate across the crystal.

Frequency - The number of occurrences of an event in a given time period (usually one second). With respect to electromagnetic waves, it is the number of waves (cycles) per second that pass a given point in space.

Frequency (electrical) - The number of times per second an alternating current goes through a complete cycle. Formerly expressed in cycles per second. Now expressed in Hertz (Hz).

Frequency Degeneracy - This occurs when a number of identical oscillators are coupled with each other and their frequencies become degenerate, i.e. having two or more levels.

Frequency Response - The ability of a device to handle the frequencies applied to it. Frequency response is quantified as the ratio of the range of the output signal to the range of the input signal.

Fresnel Diffraction ( or Near-Field Diffraction) - The condition when the light source or screen, or both, are at a finite distance to the aperture. This type of diffraction occurs when a short distance separates the mask and the wafer. It leads to error during mask exposure at mask edges and is the limiting factor for proximity aligners.

Front End - In semiconductor manufacturing, it refers to the set of fabrication processes that enable transistors to be formed on the wafer.

Front-End Of Line (FEOL) - Operations performed on the wafer starting from transistor manufacturing until first-level metallization.

Front-End Processing - Operations performed on the wafer device during manufacturing and before the first level of metallization.

Front-Opening Unified Pod (FOUP) - A wafer-handling system that combines wafer cassette and tool insert/removal func­tions. It is a critical factor for the transition from hand delivery to mechanized transp