SEMATECH Dictionary of Semiconductor Terms

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

"Ti-Tz"

tie bars n		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. [SEMATECH] Also called die pad support.
tilt n		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. [SEMI E15-91] 2 : the loss of parallelism between the die pad and the Z-plane formed by the dambars of a semiconductor devices leadframe. [SEMI G2-87]
time-weighted average (TWA) n		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. [SEMI S2-93]
timing n		the description of the absolute timing of signals propagating through a die during operation. [1994 National Technology Roadmap for Semiconductors]
tinning n		a thin layer of solder coating on metallic surfaces. [SEMATECH]
tip n		in a scanning tunneling microscope probe, a sharpened, nonoxidized, or minimally oxidized conductive point at the end. [SEMATECH]
TIR		see total indicator reading or total indicator runout.
titanium (Ti) n		an element that is used as a contact to silicon. [SEMATECH]
TLV		see threshold limit value.
toggle v		to switch a transistor between "off" and "on" states. [SEMATECH]
toluene (C6H5CH3) n		a poisonous, colorless, flammable liquid, usually obtained from coal tar or petroleum. Toluene is insoluble in water but soluble in alcohol and ether. [SEMI C1.18-90]
tool n		1 : an instrument, machine, or device used to perform a task or to measure a characteristic or quality. [SEMATECH] 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. [SEMI E15-91]
tooling n		the equipment used to mold, trim, and form plastic molded semiconductor packages. [SEMATECH]
tool suite n		the set of computer-aided design programs for creating a die/system. [1994 National Technology Roadmap for Semiconductors] .
tool-to-tool automated material handling system		see intrabay automated material handling system.
top or bottom protrusions n		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. [SEMI G14-88]
top-to-bottom cavity mismatch		see mismatch.
top face n		in plastic and metal wafer carriers, the plane or surface from which side wafers enter or exit. [SEMI E1-86]
top formed width n		the lead shoulder width on preformed dual inline cerdip leadframes. [SEMI G2-87] Also see leadframe and shoulder bend location.
torr n		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). [SEMATECH]
total available hours n		for equipment, 168 hours per week per machine. [SEMATECH]
total beads n		in an ion-exchange resin, the summation of perfect beads plus cracked, pocked, and fragmented beads. [SEMATECH]
total fixed charge density () n		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 (). [adapted from ASTM F1241]
total effect n		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. [SEMI E18-91]
total indicator reading (TIR) n		of a semiconductor wafer, the span of readings, from minimum to maximum, for any dimension measured. [SEMI G39-89]
total indicator runout (TIR) n		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. [SEMI M1-94 and ASTM F1241]
total reflection X-ray fluorescence (TXRF) n		an analytical method usually used to characterize the level of metallic (and nonmetallic elemental) surface contamination. In TXRF, an X-ray beam excites fluorescence from the contamination that is present on a silicon surface. Since the beam is incident at grazing angles, it totally reflects from the surface, thus maximizing the signal. [SEMATECH]
total thickness variation (TTV) n		of a semiconductor wafer, the difference between the maximum and minimum values of the thickness of the wafer. [ASTM F1241]
total time n		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. [SEMI E10-92]
total utilization n		the percentage of productive time during total time. This calculation is intended to reflect bottom-line equipment utilization. [SEMI E10-92]
toxic adj		describes a chemical or material that has the ability to seriously injure biological tissue. Examples of toxic substances are phosphine, diborane, and arsine. [SEMATECH]
toxic effects (TFX) n		identification of the principal organ system affected by toxic material as reported, or its pathology. [SEMATECH]
toxic gas n		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. [SEMI F1-90]
toxic material n		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 and 300 g each. SEMI S2-93]
TPG		see tester pattern (program) generation or automatic test pattern generation.
TQM-BASE Council n		abbreviation for the Training and Quality Management Boston Area Semiconductor Equipment Council, a not-for-profit association of suppliers to the semiconductor industry. [SEMATECH]
trace report n		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. [SEMI 2309, proposed]
track clearance n		in plastic and metal wafer carriers, the unobstructed area between the two sides on the crossbar end. [SEMI E1-86]
training, offline n		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. [SEMI E10-92]
training, on-the-job n		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. [SEMI E10-92]
transaction n		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. [SEMI E4-91 and E5-92] 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. [SEMATECH]
transaction timeout n		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. [SEMI E5-92]
transfer v		to either load or unload. [SEMI E23-91]
transfer agent n		in automated material movement, an equipment specialized for the transport of material from one equipment or storage area to another. [SEMI E32-94]
transfer carrier n		a vessel used to move wafers from one operation to another; for example, from diffusion to photomasking. Also used for temporary wafer storage. [SEMATECH]
transfer envelope n		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. [SEMI E32-94]
transfer job n		in automated material movement, the set of atomic transfers constructed by the host to accomplish a cohesive material movement objective. [SEMI E32-94]
transfer molding n		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. [SEMATECH]
transfer object n		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. [SEMI E32-94]
transfer partners n		in an automated material transfer, the equipment sending a transfer object and the equipment receiving the transfer object. [SEMI E32-94]
transfer specification n		in automated material movement, the list of data provided by the host to define an atomic transfer. [SEMI E32-94]
transfer standard n		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. [SEMI E29-93]
transfer system controller n		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. [SEMI E32-94]
transient overshoot n		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. [SEMI E17-91]
transient undershoot n		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. [SEMI E17-91]
transition metals n		referring to the periodic table, those elements shown as being members of groups IB, IIB, IIIB, IVB, VB, VIB, and VIII. [ASTM F1156-91]
transition width n		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. [SEMI M2-94]
transport equipment n		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. [SEMI E23-91]
transport group n		a set of substrates that are transported together between tools. [SEMI 2471, proposed]
transport module n		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). [SEMI E21-91]
transport module controller n		a virtual semiconductor device for the control of a cluster tool transport module. [SEMATECH]
transport module end effector n		that part of the transport module that supports the wafer and can extend beyond the interface plane. [SEMI E22-91]
transport resource n		in cluster tools, a component within a transport module that is capable of effecting end-to-end transfers of material. [SEMATECH]
transport server n		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. [SEMATECH]
transport vehicle n		a vehicle that transports cassettes but has no mechanism for cassette transfer. [SEMI E23-91]
trap n		a mechanism in a vacuum pump. The trap removes moisture from gases such as oxygen. [SEMATECH]
trapped charges n		charges trapped either in the gate oxide or, in the case of a lightly doped drain (LDD) metal-oxide semiconductor field-effect transistor (MOSFET), in the spacer region. Trapped charges in the gate or the spacer lead to threshold voltage shift or to transconductance degradation, respectively. [SEMATECH]
trench n		a deeply etched area used to isolate one area from another or to form a storage capacitor on a silicon wafer. [SEMATECH]
1,1,1-trichloroethane (TCA) (Cl3CCH3) n		a poisonous, nonflammable, irritating liquid solvent. This compound is insoluble in water, but soluble in alcohol and ether. In a low purity, stabilized grade, this material is used to clean parts. In a purer form, it is used as a source of volatile chloride in some high temperature processes, such as oxidation. [SEMATECH]
trimetal mask		see mask, trimetal.
tripyramid		see pyramid.
true position circle n		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. [SEMI G47-88]
T/S		see thermosonic bonding.
tub n		in a dielectrically isolated (DI) wafer, a single crystal silicon region that is surrounded by an oxide layer on the sides and bottom. [SEMI M22-92]
tub depth n		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. [SEMI M22-92]
tube n		a cylindrical quartz vessel placed in a furnace to provide a contamination-free and controlled atmosphere. [SEMATECH]
tungsten (W) n		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. [SEMATECH]
tungsten hexafluoride (WF6) n		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. [SEMI C326-89]
tunneling n		a means by which electrons flow across a gap between two conductors. [SEMATECH]
turbomolecular pump n		equipment used to create a high vacuum. Rapidly rotating blades force molecules to the bottom for removal by a mechanical pump. [SEMATECH]
TWA		see time-weighted average.
tweak v		1 : to edit the execution area (object code) of a process program without changing its stored version (source code). [SEMATECH] 2 : a minor change in process parameters to correct a divergent process. [SEMATECH]
tweezer mark n		on semiconductor wafers, a mark caused by scraping tweezers across a wafer surface. [ASTM F1241]
tweezer residue n		on semiconductor wafers, contamination placed upon the wafer surface when the wafer is held with unclean tweezers. [ASTM F1241]
twin		see twinned crystal.
twin band n		a volume within a crystal bounded by twinning planes. [ASTM F1241]
twinned crystal n		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." [Adapted from ASTM F1241] Also see crystal lattice and crystallographic notation.
twist n		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. [SEMI G9-89] 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. [SEMI G2-94] Also see package.
two-way valve n		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. [SEMI Chemicals/Gases, Vol. 1, 1990 (no longer in print)] Also see metering valve.
TXRF		see total reflection X-ray fluorescence.
type n		defines the behavior of a similar group of objects. The objects are instances of the type. Also see class.

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