Page 394 - A Practical Guide from Design Planning to Manufacturing

364 Glossary

Doping Adding impurities to a semiconductor to create free charge carriers.
Double precision A binary floating point number format using 64 bits.

DPM Defects per million.
Drain terminal One of the diffusion terminals of a MOSFET.
DRAM Dynamic random access memory.
Dry etch An etch step performed using gases or plasma rather than liquid
chemicals.
DSC Die side cap.
Dual damascene A damascene process where trenches are etched for vias
and interconnects and both are filled with conducting material simultaneously.
Dual in-line package (DIP) A package with single rows of leads on two sides
of the package. These packages typically have less than 50 total leads.
Dynamic random access memory (DRAM) Semiconductor memory using
single transistor (1T) cells, which gradually leak away charge and must be
refreshed approximately every 15 ms. DRAM chips provide the lowest cost per
bit of the different types of semiconductor memory and therefore are used as the
main memory store of almost all computers.
ECC Error correcting code.
Electrical test (E-test) Tests performed on a wafer, sometimes before pro-
cessing is complete, to measure the electrical properties of the structures man-
ufactured so far. Used to detect problems in the manufacturing process as early
as possible.
Electromigration (EM) The tendency of high current densities to cause inter-
connects to fail over time by causing the movement of atoms out of thin spots
in the wire.
Embedded processor A processor used in a product other than a computer.
EPIC Explicitly parallel instruction computing.
Epitaxy The deposition of a crystalline layer on top of a crystal substrate.
Epi-wafer A wafer made by depositing a crystalline epitaxial layer on top of a
bulk wafer. This allows the creation of doping profiles that could not be created
through traditional diffusion.
Errata Documented processor behaviors that are different from the design’s
intended behavior but are deemed unlikely or trivial enough that the processor
design is still sold.
Error correcting codes (ECC) Schemes for adding redundant bits to memory
stores to allow misread bits to be detected and in some cases corrected.
Etch rate The thickness of material, which can be removed by an etch step in
a fixed length of time.