|
TAB:
Tape Automatic Bonding. The process where silicon chips are
joined to patterned metal traces (leads) on polymer tape to
form inner leads bonds and subsequently the leads are attached
to the next level of the assembly, typically a substrate or
board, to form outer lead bonds. TAB is the technique of interconnecting
silicon with beam bonding as opposed to wire bonding.
TAB Component:
An IC mounted on a TAB site.
TAB Tape Site or TAB Frame:
An individual component mounting site on TAB
tape.
TAB Tape:
A polymer film with patterned metal traces or leads. It is
only a temporary support that is almost completely removed
during the transfer of the chip from the tape to the substrate.
The TAB tape can be handled in continuous tape or slide carrier
format.
Tackiness:
The ability of solder paste to hold surface mount components
in place after placement but before reflow soldering.
Tape-and-reel:
Component packaging for placement via housing parts in cavities
in a continuous strip. The cavities are covered by a plastic
tape so that they can be wound in a reel for presentation
to a component placement machine.
Tape Automated Bonding:
(see TAB)
Tape Bonding:
Utilization of a metal or plastic tape material as a support
to a carrier of a component in a gang bonding process.
Tape Ball Grid Array (TBGA):
A BGA package on a copper polyimide base like TAB,
except TAB leads are replaced by an area array ball grid for
interconnects. A stiffener is added to ensure flatness for
the mass reflow assembly process.
Terminal:
A metallic device used for making electrical connections.
Test Board:
A printed circuit board deemed to be suitable for determining
the acceptability of a group of boards produced with the same
fabrication process.
Test Fixture:
A device that interfaces between test equipment and the unit
being tested.
Test Pads:
Contact points on TAB tape, located outside the OLB window,
that are used to facilitate testing and burn-in of the IC
while it is in the TAB frame. Test pads remain with the discarded
portion of the carrier after excising.
Test Pattern:
A pattern used for inspecting or testing purposes.
Test Point:
A specific point of access to an electrical circuit used for
electrical testing purposes.
Thermal Conductivity:
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 period of time.
Thermal Cycling:
A method used to induce stresses on electrical components
by means of sequential heating and cooling in an oven. It
is used in accelerated reliability testing.
Thermal Profile:
A time versus temperature graph that displays the temperatures
an assembly is subjected to over time in an oven during processes
such as reflow soldering or the curing of adhesives, encapsulants,
and conformal coatings.
Thermocompression Bonding:
The joining of two materials without an intermediate material
by the application of pressure and heat in the absence of
electrical current.
Thermocouple:
A sensor made of two dissimilar metals which, when heated,
generate a small DC voltage used in temperature measurements.
Thermode:
A set of blades or bars that are pulse-heated. A thermode
is used to hold component leads in place and reflow solder
them to bonding pads on a substrate during hot bar reflow
soldering.
Thermoplastic:
Polymer materials that can be repeatedly melted without significant
change in their properties.
Thermosetting Plastic:
Polymer materials that cure (irreversably polymerize) at specific
temperature and time conditions.
Thixotropic Ratio:
An indication of thixotropy as a ratio of viscosities at two
different shear rates.
Thombstoning:
A soldering defect in which a chip component is pulled into
a vertical position leaving one side unsoldered.
Three Layer TAB Tape:
Tape constructed with a conductive metal layer, typically
35 micron thick copper; a flexible heat resistant support
layer, typically 125 micron thick polyimide; and an adhesive
layer between the conductive layer and the flexible support
layer. The polyimide thickness is not limited in the three
layer tape manufacturing process because the openings in the
tape are punched out rather than etched. The copper is usually
tin or gold plated.
Threshold Limit Value:
A guideline for the exposure of humans to solvents; it is
expressed as a Time Weighted Average (TWA) of the parts per
million of vapor in air.
Through Hole:
A hole connecting the two surfaces of a printed circuit structure.
Tie Bars:
Polyimide strips, or bars, connecting an inner ring at its
corners to the remainder of the TAB
tape site. Also referred to as suspenders.
Tinning:
The process of coating metallic surfaces with a thin layer
of solder.
Tip-to-Tip Dimension:
With respect to component geometry, the distance between the
ends of the leads on opposite sides of a component after excising
and forming.
Tombstoning:
The lifting of one end of a passive surface mount component
during solder reflow caused by surface tension and unbalanced
forces of solder wetting.
Torsional Strength:
The torque required to separate adhesive bonded (and cured)
materials and/or components.
Touch-Up:
The identification and elimination of defects in a product.
Transistor:
An active semiconductor device capable of providing power
amplification. Transistors have three or more terminals.
Two Layer TAB Tape:
This tape is constructed with a conductive metal layer, typically
35 micron thick copper, and a flexible heat resistant support
layer, typically 50 micron thick polyimide. The support layer
thickness is limited to 50 microns or less due to chemical
etching limitations of the two layer TAB tape manufacturing
process. The copper is usually tin or gold plated.
Type I Assembly:
A surface mount assembly with surface mount components on
one or both sides of the substrate.
Type II Assembly:
A surface mount assembly with surface mount components on
one or both sides of the substrate and through hole devices
on the primary side.
Type III Assembly:
A surface mount assembly with surface mount components on
the secondary side of a PCB and through hole devices on the
primary side.
|
