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T/C
see thermocompression.
T/S
see thermosonic bonding.
T1
in the block transfer protocol, the receive intercharacter timeout (T1). NOTE-A timeout detects communications failures. T1 limits the time between receipt of characters within a message block after the length byte has been received. It continues to limit the time until the receipt of the second checksum byte.
T2
in the block transfer protocol, the protocol timeout. NOTE-A timeout detects communications failures. T2 limits the time between (1) the sending of ENQ (the code for "Request to Send") and the reception of EOT (the code for "Ready to Receive"); (2) the sending of EOT and the reception of the length byte; and (3) the sending of the checksum byte and the reception of any character.
T3
in the message protocol, the reply timeout. NOTE-A timeout detects communications failures. T3 is a limit on the length of time that the message protocol will wait after the last block of a primary message has been sent and before the arrival of the first block of the reply. A transaction timeout occurs when T3 expires.
T4
in the message protocol, the inter-block timeout. NOTE-A timeout detects communications failures. T4 is a limit on the time interval between the successful receipt of a block in a multiblock message and the receipt of the subsequent block of the same message.
Tack weld
in metal lid/preform assembly, small spot welds, generally located in the corners, that are used to attach the preform to the lid.
Take-Off Angle (TOA)
in electron spectroscopy for chemical analysis, the angle of the lens axis with respect to the sample plane.
TAM
Total Available Market. Used to show actual dollars spent in a market.
Tangential focal surface
in the measurement of photolithographic instruments, the focal surface determined by examining only the tangential lines.
Tangential lines
in the measurement of photolithographic instruments, an evaluative line pattern in which the lines lie perpendicular to a radius to the optical axis.
Tape Automated Bonding (TAB)
a method of making an electrical interconnection between a die and a substrate by using conductors on beam tape that are mass bonded to bumps on the integrated circuit in a single operation.
Taper
of a semiconductor wafer, the linear component of the variation in thickness across a wafer, indicated by the angle between the best fit plane to the front surface and the ideally flat back surface of the wafer. Also called wedge.
Target audience
the audience that needs to be advised of a hazard.
Task analysis
an organized approach to analyzing a job or a task in which all the elements of the activity are defined, including knowledge requirements, skills, equipment, tools, materials, sequencing, number of steps, resources, safety issues, related procedures, and training.
Taylor tray
a brown-clay soil formation that is shifting and highly expansive.
TC
see thermocouple.
TCA
see 1,1,1-trichloroethane.
TCP/IP
abbreviation for transmission control protocol/internet protocol; the standard accepted by the U.S. Department of Defense for governing information interchange and communications between host computers.
Technology buys
Purchases of advanced equipment by the semiconductor industry for developing next generation technologies and other R&D, as opposed to buying equipment in order to increase manufacturing capacity (capacity buys).
Technology driver
leading-edge process/product technology that drives development of next-generation equipment, unit processes, and manufacturing techniques. Essential elements include high-volume diagnostic techniques for accelerated learning and a large revenue stream with which to fund research and development and capital investment.
Technology libraries
the codified form of the information required by computer-aided programs that completely describes the circuit family being used. These library parameters include (but are not limited to) items such as delay equations, power characteristics, geometric shapes, and simulation models.
Telecom
Telephone communications. See SLICs.
Temperature coefficient
in regulator performance testing, the average rate of change of the regulator's set point per degree of temperature change, that is, Pa per 1 degree C. The temperature coefficient may be positive (set point increases with increasing temperature) or negative (set point decreases with increasing temperature) or both.
Temperature coefficient curve
in regulator performance testing, a plot of set point versus temperature from which the temperature coefficient can be determined.
Temperature cycling
a stress test in which components are repeatedly exposed to extreme hot and cold temperatures.
Temperature-Sensitive Parameter (TSP)
in the thermal testing of semiconductor packages, the temperature-dependent electrical characteristic of a semiconductor junction in the device under test that can be calibrated with reference to temperature and subsequently used to detect the junction temperature of interest.
Template
1: a model that describes a pattern of program input to be recognized or a pattern of output to be produced. 2: a format, overlay, or form used to generate consistent product. Examples are a reticle or mask in semiconductor manufacturing, a standard format for documents, and a computer keyboard overlay.
Tensile
having to do with the longitudinal stress applied to lengthen a test object.
TEOS
TetraEthylOrthoSilicate, a liquid source oxide deposition with excellent uniformity, step coverage and film properties. Disadvantage is high temperature and liquid source requirements. See deposition.
Teratogen
a chemical agent that causes congenital malformations in a developing embryo or fetus.
Terminal
1: on a semiconductor package, an external lead or contact pad for electrical connection between the inner circuitry of the package and exterior circuitry on a circuit board or substrate. 2: in data communication, a device, usually equipped with a keyboard and display device, capable of sending and receiving information.
Terminal emulator
a computer program that runs on a computer and causes the computer to act like a specified terminal.
Terminal-based linearity
in the linearity of mass flow devices, the maximum deviation of the calibration curve from a straight line that intercepts the calibration curve at upper and lower input range values.
Terracing a network
of contours that are associated with pyramid-like defects on epitaxially deposited surfaces and are related to the orientation of the surface.
Test flow rate
in fluid distribution system component testing, volumetric flow at test pressure and temperature.
Test method
a definitive procedure for the identification, measurement, and evaluation of a material, product, system, or service that produces a test result.
Test pattern
see pattern, test.
Test pressure
in fluid distribution system component testing, pressure immediately downstream of the test component.
Test program
The total computer code that instructs automatic test equipment exactly how the integrated circuit is to be tested.
Test strategies
choosing which techniques from those available that will be used as part of a specific chip design.
Test techniques
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 and boundary scan.
Test vectors
sequences of signals applied to the pins of an integrated circuit to determine whether the integrated circuit is performing as it was designed.
Test vehicle
a fully functional circuit used to demonstrate process integration and control.
Test vehicle
A fully functional product or an array of test devices and structures used to develop process integration and control.
Test wafer
see wafer, test.
Testability
the ease with which tests can be generated for and applied to a given circuit.
Testability
A descriptor of a general area of circuit design that deals with how testable a particular circuit design is going to be. Specific implementations of structures and test methods that make circuits more testable and provide higher level fault coverage provide better testability. See design for testability.
Testability metrics
measures that determine whether an integrated circuit is easy or hard to test; alternatively, they can measure how effectively a given set of test vectors tests the integrated circuit for a particular type of fault.
Tester Pattern Generation (TPG)
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. Also called tester program generation.
Tetrachlorosilane
see silicon tetrachloride.
Tetrafluoromethane
see carbon tetrafluoride.
Theoretical cycle time
the summation of cycle times of individual value-added operations at the minimum known process time for a single unit of product for a manufacturing sequence. This definition of theoretical cycle time includes the load, process, and unload times and does not include transportation, set up, queue, downtime, metrology, or production test, which would be considered process inefficiencies.
Theoretical equipment capacity
potential number of product wafers the equipment could process during total time if there were no nonscheduled time, unscheduled or scheduled downtime, engineering or stand-by time allowed. (This can also be viewed as the maximum processing rate for a given piece of equipment.) Contrast throughput.
Thermal deposition
a process in which chemical dopants are introduced onto a silicon wafer in a controlled atmosphere at temperatures typically greater than 950 degrees C.
Thermal emf
the net electromotive force (emf) set up in a thermocouple under conditions of zero current. Also called Seebeck emf.
Thermal oxidation
the reaction of silicon with oxygen at temperatures near 1000 degrees C to form silicon dioxide.
Thermal shock
a thermal stress test in which the package is alternately dipped in hot and cold (fluorocarbon) fluid.
Thermal shrinkage
in flat panel display substrates, the shrinkage of a substrate caused by the relaxation of thermal stress and the structure change that occur when the substrate is heat treated along a specific thermal profile. Usually thermal is described with L , where L is the amount of change, and shown as L= - L. is the length of material before heat treatment and L is after heat treatment.
Thermal transient testing
a technique for evaluating the integrity of semiconductor die attachment. Semiconductor die are sensitive to voids in the die attach medium-organic resin, metal alloys, or solders. The voids impede the flow of heat away from the die to the package or substrate and may also create cracks in the die when it is exposed to large temperature variations in thermal testing. Tests may be conducted on unencapsulated thermal test chips or on active devices.
Thermal transition
in the thermal testing of fluorocarbon tube fitting connections, a change from a specific elevated fluid temperature down to room temperature and then to an elevated temperature higher than previously tested, with the entire process repeated under multiple temperature conditions.
Thermocompression (T/C) bonding
a process that involves the use of pressure and temperature to join two materials by interdiffusion across the boundary.
Thermocouple (TC)
a pair of dissimilar metal wires; used for accurate measurement of temperature.
Thermography, infrared
the process of displaying variations of apparent temperature (variations of temperature or emissivity, or both) over the surface of an object or a scene by measuring variations in infrared radiance.
Thermosonic bonding (T/S)
a packaging bonding process that uses a combination of thermocompression bonding and ultrasonic energy bonding.
Thick film
a package layer deposited by screen printing and fired at high temperatures in order to fuse it into final form. Also see thick film metallization.
Thick film metallization
metallization that is deposited onto a ceramic substrate or layer by a screen printing process to achieve a layer of metal usually, by industry standards, in the 0.0003 to 0.001-in. thickness range.
Thickness
1: of an epitaxial layer, the distance from the surface of the wafer to the layer-substrate interface. [SEMI M2-94 and ASTM F1241] 2: of a semiconductor wafer, the distance through the wafer between corresponding points on the front and back surfaces.
Thickness variation
in flat panel display substrates, any differences between maximum and minimum values within the thickness of a glass substrate. Also see total thickness variation.
Thin film
a specific class of either conducting or insulating film deposited onto a wafer surface.
Thin film packaging
a packaging method in which the conductors or insulators, or both are fabricated by means of deposition and patterning techniques.
Three-ported two-way valve
a type of shutoff valve of the basic two-way design, having either a single inlet port and two interconnected outlet ports or two interconnected inlet ports and a single outlet port.
Three-way valve
a type of shutoff valve having two extreme positions, each of which either (1) directs an incoming single-gas stream to one of two alternate outlet ports, or (2) directs two different incoming gas streams alternately to a single outlet port. Some designs of three-way valves incorporate a position in which all ports are closed to flow.
Threshold
a level set within the control software of a measurement instrument such that a signal that exceeds this level is recorded as an event and a signal below this level is ignored.
Threshold adjustment
an ion implant of approximately 1 x 1011/cm2 using, for example, phosphorus, arsenic, or boron to controllably increase or decrease the threshold voltage of a metal oxide semiconductor transistor.
Threshold Limit Value (TLV)
the American Conference of Governmental Industrial Hygienists (ACGIH) guideline for the airborne concentration of a material to which nearly all U.S. workers can be exposed day after day without adverse effect.
Throughput
the number of wafers per hour through a machine, assuming 100% equipment uptime and a fully loaded machine. The number is adjusted downward for any detracting factors one wants to consider (for example, downtime, setup time, idle time, etc.)
Thyristor
Derived from "gas thyratron" because of the similarity in its operating characteristics with a thyristor. A family of semiconductor devices that exhibit bi-stable current-voltage characteristics and can be switched between a high-impedance, low-current "off" state and a low-impedance, high-current "on" state. Thyristors contain a series connection of three P-N junctions, and are used predominantly for power switching applications.
Tie bars
the metal bars that hold the die attach pad of a leadframe to the rails of the leadframe. After molding, these connections to the rails are trimmed away. Also called die pad support.
Tile array
Primarily used in analog ASIC design styles, a tile array is a pre-established layout of electrical devices which can be configured to create a number of different (although related) electrical functions by means of programming the levels of interconnecting material. Since the cost of producing the underlying devices is spread over all designs using a particular tile array, a customer may create very cost-effective solutions to analog design requirements using a high performance dielectrically isolated process (DI). With tile arrays, customer-specific programming requires only two or three masks rather than 12 or 15.
Tilt
1: a small angle of offset from the normal horizontal or vertical surfaces of a cassette or container, designed to preferentially align or keep wafers in their normal places. 2: the loss of parallelism between the die pad and the Z-plane formed by the dambars of a semiconductor devices leadframe.
Time-Weighted Average (TWA)
in safety threshold limit values, the time-weighted average concentration for a normal 8-hour workday and a 40-hour workweek, to which nearly all workers may be repeatedly exposed, day after day, without adverse effect.
Timing
the description of the absolute timing of signals propagating through a die during operation.
Tinning
a thin layer of solder coating on metallic surfaces.
Tip
in a scanning tunneling microscope probe, a sharpened, nonoxidized, or minimally oxidized conductive point at the end.
TIR
see total indicator reading or total indicator runout.
Titanium (Ti)
an element that is used as a contact to silicon.
TLM
Triple-Level Metal. An IC metal interconnect process that employs three vertical levels of metal, separated by insulating layers. Such a dense configuration requires that each metal interconnect layer be made planar before the subsequent layer is deposited. See DLM and SLM.
TLV
see threshold limit value.
TLV
see threshold limit value.
Toluene (C6H5CH3)
a poisonous, colorless, flammable liquid, usually obtained from coal tar or petroleum. Toluene is insoluble in water but soluble in alcohol and ether.
Tool
1: an instrument, machine, or device used to perform a task or to measure a characteristic or quality. 2: any piece of semiconductor fabrication or inspection equipment designed to process wafers delivered in cassettes or cassettes in containers intended for use with an automated material transport system.
Tool suite
the set of computer-aided design programs for creating a die/system.
Tooling
the equipment used to mold, trim, and form plastic molded semiconductor packages.
Tool-to-tool automated material handling system
see intrabay automated material handling system.
Top face
in plastic and metal wafer carriers, the plane or surface from which side wafers enter or exit.
Top formed width
the lead shoulder width on preformed dual inline cerdip leadframes. Also see leadframe and shoulder bend location.
Top or bottom protrusions
in the manufacture of plastic molded DIP package tooling, those plastic excesses, including ejector pin crowns, that remain as normal characteristics extending from the smooth surface of the molded package.
Top-to-bottom cavity mismatch
see mismatch.
Torr
unit of measure for the pressure exerted by 1 mm of mercury, equal to 1/760th of standard atmospheric pressure; used to measure pressure in vacuum systems. The corresponding SI unit is the pascal (Pa).
Total available hours
for equipment, 168 hours per week per machine.
Total beads
in an ion-exchange resin, the summation of perfect beads plus cracked, pocked, and fragmented beads.
Total dose
Term used to describe the total exposure of an IC to ionizing radiation, typically gamma rays, energetic electrons, or X-rays. Most commercial ICs are very sensitive to ionizing radiation and degrade in their performance upon exposure.
Total effect
in the temperature specifications of mass flow devices, the change in output, including zero and span, due to a change in ambient temperature from one normal operating temperature to a second normal operating temperature. All other conditions must be held within the limits of reference operating conditions.
Total fixed charge density
the sum of the following nonmobile charge densities on a silicon surface: oxide fixed charge density, oxide trapped charge density, and interface trapped charge density.
Total Indicator Reading (TIR)
of a semiconductor wafer, the span of readings, from minimum to maximum, for any dimension measured.
Total Indicator Runout (TIR)
1: of a semiconductor wafer, the smallest perpendicular distance between two planes, both parallel with the reference plane, that enclose all points on the front surface of a wafer within either the fixed quality area (FQA) or the site, depending on which is specified.
Total Reflection X-Ray Fluorescence (TXRF)
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.
Total Thickness Variation (TTV)
of a semiconductor wafer, the difference between the maximum and minimum values of the thickness of the wafer.
Total time
in equipment reliability, all the time (at the rate of 24 hours per day and 7 days per week) during the period being measured. To have a valid representation of total time, all six basic equipment states must be accounted for and tracked accurately.
Total utilization
the percentage of productive time during total time. This calculation is intended to reflect bottom-line equipment utilization.
Toxic
describes a chemical or material that has the ability to seriously injure biological tissue. Examples of toxic substances are phosphine, diborane, and arsine.
Toxic effects (TFX)
identification of the principal organ system affected by toxic material as reported, or its pathology.
Toxic gas
a substance that is discharged into a piping system in gaseous form and that is defined as toxic or highly toxic in Title 29 of the Code of Federal Regulations, Section 1910.1200.
Toxic material
material that produces a lethal dose or a lethal concentration within any of the following categories : a chemical or substance that has a median lethal dose (LD ) of more than 50 mg per kilogram but not more than 500 mg per kilogram of body weight when administered orally to albino rats weighing between 200 and 300 g each a chemical or substance that has a median lethal dose (LD ) of more than 200 mg per kilogram but not more than 1000 mg per kilogram of body weight when administered by continuous contact for 24 hours (or less if death occurs within 24 hours) with the bare skin of albino rabbits weighing between 2 or 3 kg each a chemical or substance that has a median lethal concentration (LC ) in air more than 200 parts per million (ppm) but not more than 2000 ppm by volume of gas or vapor, or more than 2 mg per liter but not more than 20 mg per liter of mist, fume or dust when administered by continuous inhalation for one hour (or less if death occurs within one hour) to albino rats weighing between 200 an
TPG
see tester pattern (program) generation or automatic test pattern generation.
TQM
Total Quality Management. See Quality First initiative.
TQM-BASE Council
abbreviation for the Training and Quality Management Boston Area Semiconductor Equipment Council, a not-for-profit association of suppliers to the semiconductor industry.
Trace report
in equipment communications, a class of objects that provides to a service user a means for collecting periodic readings of selected attributes of a system.
Track
Sometimes called resist track. A common name for a spin coater. See spin coater
Track clearance
in plastic and metal wafer carriers, the unobstructed area between the two sides on the crossbar end.
Training, offline
the instruction of personnel in the operation or maintenance, or both, of equipment done outside of operations time. Offline training is included only in nonscheduled time.
Training, on-the-job
the instruction of personnel in the operation or maintenance, or both, of equipment done during the course of normal work functions. On-the-job training typically does not interrupt operation or maintenance activities and, therefore, can be included in any equipment state without special categorization.
Transaction
1: a pair of messages that consists of a primary message and its associated secondary message, if any. NOTE-A transaction is opened when a primary message is ready to be sent and is closed when the last block of a primary message requesting no reply has been sent or when the last block of the reply has been received. A number of transaction-level requirements are specified by SECS-II. Also see transaction timeout. 2: in database management systems, a number of individual data updates that must either be completely performed as a group, or all rolled back, in order to leave the database in a consistent state.
Transaction timeout
an indication from the message transfer protocol that a transaction (which consists of the first message sent and the second message sent in reply) has not completed properly. NOTE-A transaction timeout occurs when T3 (reply timeout) expires.
Transfer
to either load or unload.
Transfer agent
in automated material movement, an equipment specialized for the transport of material from one equipment or storage area to another.
Transfer carrier
a vessel used to move wafers from one operation to another; for example, from diffusion to photomasking. Also used for temporary wafer storage.
Transfer envelope
in automated material movement, the three-dimensional space occupied during the transfer by the transfer object and all associated transfer mechanisms of both transfer partners. This defines the space in which transfer activity occurs, and in which the potential for physical interference with the transfer exists.
Transfer job
in automated material movement, the set of atomic transfers constructed by the host to accomplish a cohesive material movement objective.
Transfer molding
a semiautomated type of thermoset molding in which a preform of plastic, such as epoxy, is transferred from a pot into a hot mold cavity.
Transfer object
in automated material movement, a physical object that is transferred to and from equipment, such as a product material, an empty carrier, or a carrier containing material to be processed. Tools, such as stepper reticles, and expendable materials also may be transfer objects.
Transfer partners
in an automated material transfer, the equipment sending a transfer object and the equipment receiving the transfer object.
Transfer specification
in automated material movement, the list of data provided by the host to define an atomic transfer.
Transfer standard
in the calibration of mass flow devices, a device typically calibrated against a primary standard that can guarantee sufficient accuracy to, in turn, calibrate another device.
Transfer system controller
in automated material movement, the entity that is responsible for management of multiple transfer agents. The transfer system controller presents a single communications interface to its host representing these multiple agents.
Transient overshoot
in mass flow controller testing, the maximum change in actual flow minus the steady state change in actual flow, expressed as a percentage of the set point step change.
Transient over-voltage
A condition in electrical circuits resulting from a sudden release of energy. Often this condition is precipitated by a static discharge, lightning, or switching of an inductive load. May occur in repeated fashion or randomly. See over-voltage.
Transient radiation
A pulse of ionizing radiation. Transient radiation can cause data upset, device latchup, and destruction of unprotected ICs. Properly designed ICs however, can resist such effects to high levels of transient radiation.
Transient suppression
See over-voltage protection.
Transient undershoot
in mass flow controller testing, the maximum amount that the actual flow passes the final steady state value, in the opposite direction of overshoot, expressed as a percentage of the set point step change.
Transistor
A three-terminal active semiconductor device that provides current amplification. A bipolar transistor is comprised of base, emitter and collector and is a current-controlled device with a low input impedance. A field-effect transistor has gate, source, and drain electrodes and is a high-impedance, voltage controlled device. The first transistor was invented at Bell Laboratories in 1947 by Nobel-Prize physicists John Bardeen, William Shockley and Walter Bratain. See base, bipolar transistor, collector, drain, emitter, field-effect transistor, gate, MOSFET and source.
Transition metals
referring to the periodic table, those elements shown as being members of groups IB, IIB, IIIB, IVB, VB, VIB, and VIII.
Transition width
of an epitaxial layer deposited on a more heavily doped substrate of the same conductivity type, the difference between the layer thickness as determined by infrared reflectance and the flat zone based on the same thickness measurement.
Transport equipment
a piece of equipment (or system) that transports or transfers cassettes. It mainly consists of a transport vehicle, a robot vehicle, and a cassette transfer robot.
Transport group
a set of substrates that are transported together between tools.
Transport module
in modular equipment, a module (independently operable unit) within a cluster tool. It accepts or presents a single wafer outside the module across the interface plane for intratool transport (wafer movement within the cluster tool).
Transport module controller
a virtual semiconductor device for the control of a cluster tool transport module.
Transport module end effector
that part of the transport module that supports the wafer and can extend beyond the interface plane.
Transport resource
in cluster tools, a component within a transport module that is capable of effecting end-to-end transfers of material.
Transport server
in a cluster tool control system, a server associated with an individual transport module that allows access to all services provided by the transport module. The services of concern to this standard are those necessary to perform end-to-end wafer transfers between any two attached modules of that transport module.
Transport vehicle
a vehicle that transports cassettes but has no mechanism for cassette transfer.
Trap
a mechanism in a vacuum pump. The trap removes moisture from gases such as oxygen.
Trapped charges
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.
Trench
a deeply etched area used to isolate one area from another or to form a storage capacitor on a silicon wafer.
Trimetal mask
see mask, trimetal.
Tripyramid
see pyramid.
True position circle
in a leadframe, that circle with its center positioned at the center of the coined area of the lead. The true position circle defines the design position of the lead tip.
TSOS4
An advanced wafer process used to prepare rad-hard 64k SOS SRAMs. It features 1.25µm feature size and double-level metal.
TTL
Transistor-Transistor Logic. A bipolar technology used for producing logic gates. Positioned in the evolution of logic families after RTL (resistor transistor logic), DTL (diode transistor logic) and before ECL and CMOS. See gate.
Tub
in a dielectrically isolated (DI) wafer, a single crystal silicon region that is surrounded by an oxide layer on the sides and bottom.
Tub depth
in dielectrically isolated (DI) wafers, the thickness of the tub as measured from the wafer surface to the buried oxide layer parallel to the wafer surface.
Tube
a cylindrical quartz vessel placed in a furnace to provide a contamination-free and controlled atmosphere.
Tungsten (W)
a hard and brittle element that is one of the materials used for heating elements in diffusion furnaces. Tungsten is also used for metallization in integrated circuits.
Tungsten hexafluoride (WF6)
a colorless, odorless gas or a light yellow liquid. Tungsten hexafluoride is used to deposit tungsten silicide during chemical vapor deposition. It also is used in the formation of tungsten conductive films.
Tunneling
a means by which electrons flow across a gap between two conductors.
Turbomolecular pump
equipment used to create a high vacuum. Rapidly rotating blades force molecules to the bottom for removal by a mechanical pump.
TVS
Transient Voltage Suppressor. A general category of devices that protect other electronic circuits, components or systems from destructive transient voltage spikes. The Harris family of TVS types include MOVs, Zener diodes, and surgectors.
TWA
see time-weighted average.
Tweak
version (source code). 2: a minor change in process parameters to correct a divergent process.
Tweezer mark
on semiconductor wafers, a mark caused by scraping tweezers across a wafer surface.
Tweezer residue
on semiconductor wafers, contamination placed upon the wafer surface when the wafer is held with unclean tweezers.
Twin
see twinned crystal.
Twin band
a volume within a crystal bounded by twinning planes.
Twinned crystal
a crystal in which the lattice consists of two parts related to each other in orientation as mirror images across a coherent planar interface known as the "twinning plane," or "twin boundary." Also see crystal lattice and crystallographic notation.
Twist
1: in a semiconductor leadframe, the angular rotation of the tips of the bond fingers with respect to the major plane of the leadframe as established by the Z-plane. Also called lead twist. 2: in a semiconductor leadframe strip, the angular rotation of one end of the strip with reference to the other end. Also see package.
Two-way valve
a type of shutoff valve having two extreme positions, on and off. Adjustability between the two extremes may provide metering capability, depending on valve design. Also see metering valve.
TXRF
see total reflection X-ray fluorescence.
Type
defines the behavior of a similar group of objects. The objects are instances of the type. Also see class.
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