IPC-T-50F_.pdf.pdf - 第73页

Thick Film 45.1545 A ﬁlm, greater than 0.1 mm (0.004-inch) thick, deposited by screen printing and subsequently ﬁred at high tempera- tures in order to fuse it into its ﬁnal functional form. Thick-Film Circuit 83.1073 A …

Terminal Hole 22.1054

see ‘‘Component Hole.’’

Terminal Pad 22.1055

see ‘‘Land.’’

Terminations 22.1773

To connect a line to a terminal, distributing frame, switch

or matrix.

Terpenes 76.1774

(Turpentine). A solvent used in cleaning electrical assem-

blies.

Test Board 92.1683

A printed board or discrete-wiring board that is deemed to

be suitable for determining the acceptability of a group of

boards that were, or will be, produced with the same fabri-

cation processes. (See also ‘‘Capability Test Board.’’)

Test Coupon 92.1820

A portion of quality conformance test circuitry that is used

for a speciﬁc test, or group of related tests, in order to

determine the acceptability of a product.

Test Language 92.1057

A high-level language used to write a test program.

Test Master 92.1058

Artwork that contains speciﬁed anomalies or degrees of

defect that an inspection or testing system should be

capable of detecting.

Test Pattern 92.1059

A pattern that is used for inspection or testing purposes.

Test Point 92.1060

A special point of access to an electrical circuit that is used

for electrical testing purposes.

Test Program 92.1061

The set of instructions to a tester that controls the unit

under test.

Test Set 92.1062

The unique combination of test programs and test ﬁxtures

that control the unit under test.

Test Step 92.1063

The application of a single input vector.

Testing Personnel 92.1056

Those individuals that test products for the purpose of

ascertaining the conformance of a product to applicable

speciﬁcations.

Tetrafunctional Resins 75.1064

Materials that have four reactive groups per molecule.

Thermal Coefficient of Expansion (TCE) 21.1065

see ‘‘Coefficient of Thermal Expansion (CTE).’’

Thermal Conductivity 20.1066

The property of a material that describes the rate at which

heat will be conducted through a unit area of the material

for a given driving force.

Thermal Expansion Mismatch 20.1067

The absolute difference between the thermal expansion of

two components or materials. (See also ‘‘Coefficient of

Thermal Expansion (CTE).’’)

Thermal Relief 22.1068

The crosshatching of a ground or voltage plane that mini-

mizes blistering or warping during soldering operations.

Thermal Shunt 30.1069

see ‘‘Heatsink.’’

Thermal Zone 50.1542

A metal-integrity evaluation zone that extends a speciﬁed

distance beyond the ends of the lands in a microsection of

a vertical portion of a plated-through hole. (Unless other-

wise speciﬁed, the extended distance is 0.08 mm [0.003-

inch].)

Thermocompression Bonding 74.1543

The joining together of two materials without an interme-

diate material by the application of pressure and heat in the

absence of electrical current.

Thermode 75.1070

A contact heating element that is used to generate reﬂow

soldering heat.

Thermoplastic 40.1071

A plastic that can be repeatedly softened and reshaped,

without any signiﬁcant change in inherent properties, by

exposure to heat and hardened by cooling.

Thermoset 40.1544

A plastic that undergoes a chemical reaction when exposed

to elevated temperatures that leads to it having a relatively

infusable or crosslinked stated that cannot be softened or

reshaped by subsequent heating.

Thermosonic Bonding 74.1072

Terminations made by combining thermocompression and

ultrasonic bonding principles.

IPC-T-50F June 1996

Thick Film 45.1545

A ﬁlm, greater than 0.1 mm (0.004-inch) thick, deposited

by screen printing and subsequently ﬁred at high tempera-

tures in order to fuse it into its ﬁnal functional form.

Thick-Film Circuit 83.1073

A microcircuit in which passive components of a ceramic-

metal composition are formed on base material by screen-

ing and ﬁring.

Thick-Film Hybrid Circuit 83.1074

A hybrid circuit with thick-ﬁlm components and intercon-

nections.

Thick-Film Network 83.1075

A hybrid circuit comprised only of thick-ﬁlm components

and interconnections.

Thin Film 45.1079

A ﬁlm, less than 0.1-mm (0.004-inch) thick, deposited by

accretion process, such as vacuum or pyrolytic deposition.

Thin-Film Hybrid Circuit 83.1076

A hybrid circuit with thin-ﬁlm components and intercon-

nections. (See also ‘‘Hybrid Circuit.’’)

Thin-Film Integrated Circuit 83.1077

A hybrid integrated circuit comprised only of thin-ﬁlm

components and interconnections. (See also ‘‘Hybrid Inte-

grated Circuit.’’)

Thin-Film Network 83.1078

A hybrid circuit comprised only of thin-ﬁlm components

and interconnections.

Thin Foil 45.1080

A metal sheet that is less than 0.02mm (0.0007 inch) thick.

Thinner (Liquid) 76.1081

A nonactivated solvent or solvent system that is used to

replace evaporated solvent and to reduce the solids content

of another substance.

Thixotropic Ratio 49.1082

An indication of thixotropy in the form of the ratio of vis-

cosities measured at two different shear rates.

Thixotropy 49.1083

A property of a substance, e.g., an adhesive system, that

allows it to get thinner upon agitation and thicker upon

subsequent rest.

Three-Layer Carrier Tape 36.1546

The carrier for conductors used in tape-automated bonding

that consists of a dielectric layer, an adhesive, and a etched

metal-foil conductor layer. (See also ‘‘Multilayer Carrier

Tape,’’ ‘‘Single-Layer Carrier Tape,’’ and ‘‘Two-Layer Car-

rier Tape.’’)

Threshold 21.1084

The magnitude of intensity that delineates that a signal is

representative of a changed state.

Through Connection 22.1086

see ‘‘Interlayer Connection.’’

Through Migration 90.1087

see ‘‘Dendritic Migration.’’

Through-Hole Mounting 72.1085

The electrical connection of components to a conductive

pattern by the use of component holes.

Tie Bar 53.1088

see ‘‘Plating Bar.’’

Tinning 71.1089

The application of molten solder to a basis metal in order

to increase its solderability.

Titrometry 92.1090

see ‘‘Volumetric Analysis.’’

Tolerance 26.1091

The total amount by which a speciﬁc dimension is permit-

ted to vary.

Toleranced Dimension 26.1092

A dimension with a tolerance.

Tombstoned Component 73.1093

A defect condition whereby a leadless device has only one

of its metallized terminations soldered to a land and has the

other metallized termination elevated above and not sol-

dered to its land.

Tooling Feature 22.1547

A physical feature that is used exclusively to position a

printed board or panel during a fabrication, assembly or

testing process. (See also ‘‘Locating Edge,’’ ‘‘Locating

Edge Marker,’’ ‘‘Locating Notch,’’ ‘‘Locating Slot,’’ and

‘‘Tooling Hole.’’)

Tooling Hole 22.1094

A tooling feature in the form of a hole in a printed board

or fabrication panel.

June 1996 IPC-T-50F

Torsional Strength 74.1095

The torque required to separate adhesive-bonded (and

cured) materials and/or components. (See also ‘‘Lap Shear

Strength’’ and ‘‘Shear Strength.’’)

Touch-Up 92.1097

The identiﬁcation and elimination of defects in a product.

Trace 22.1098

see ‘‘Conductor.’’

Track 22.1099

see ‘‘Conductor.’’

Transfer Soldering 75.1101

The use of a soldering iron to transfer a measured amount

of solder, in the form of a ball, chip, or disc, to a solder

connection.

Transfer-Bump Tape Automated Bonding 74.1100

Tape automated bonding that uses discrete bumps between

the die lands and carrier tape to facilitate inner-lead bond-

ing.

Transmission Cable 21.1102

Two or more transmission lines in the form of an

interconnection-wiring cable.

Transmission Line 21.1103

A signal-carrying circuit with controlled conductor and

dielectric material physical relationship such that its elec-

trical characteristics are suitable for the transmission of

high-frequency or narrow pulse electrical signals. (See also

‘‘Balanced Transmission Line,’’ ‘‘Microstrip’’ ‘‘Stripline,’’

and ‘‘Unbalanced Transmission Line.’’)

Transmittance 24.1104

The ratio of the amount of light that is transmitted through

an object or material to the quantity of light that is incident

upon it.

Treatment Transfer 92.1548

The transfer of copper-foil treatment to a base material as

indicated by the presence of black, brown or red streaks

after the copper has been removed by etching.

Treeing 53.1549

A dendritic-type of plating growth that extends onto the

surface that is adjacent to edge of a conductive pattern.

(This is normally caused by excessive plating current.)

Tri-State 21.1105

A high-impedance state of an electronic device that effec-

tively disconnects the device output from all other cir-

cuitry.

Trim Lines (Pattern) 22.1106

Lines that deﬁne the borders of a pattern. (See also ‘‘Cor-

ner Marks.’’)

Trim Lines (Printed Board) 22.1550

Lines that delineate the border of a printed board. (See also

‘‘Corner Marks.’’)

Trimming 77.1108

The cutting of a ﬁlm component by a laser beam or abra-

sive jet in order to modify its value.

Trimming Notch 77.1109

see ‘‘Kerf.’’

True Position 22.1110

The theoretically-exact location for a feature or hole that is

established by basic dimensions.

True Position Tolerance 22.1111

The total permissible deviation from a true position.

Trumeter 44.1112

A device used to accurately measure yardage passing a

speciﬁc point of reference.

Truth-Table Testing 21.1551

The application of electrical signals in accordance with a

prescribed logic matrix pattern that indicates the outputs

that should result from a given pattern of inputs.

Tuberculation 76.1113

The formation of localized corrosion products that are scat-

tered over a surface in the form of knob-like mounds.

Turnkey System 11.1114

A self-contained hardware and software system that per-

form a speciﬁc task.

Turret Solder Terminal 37.1552

A round post-type stud (stand-off) solder terminal with a

groove or grooves around which one or more wires are

wrapped prior to soldering. (See Figure T-1.)

IPC-I-001034

Figure T–1 Turret solder terminal

TOP SHOULDER

UPPER POST SELECTION

LOWER POST SELECTION

BASE

SINGLE TURRET DOUBLE TURRET

IPC-T-50F June 1996