Page 393 - A Practical Guide from Design Planning to Manufacturing

Glossary 363

Damascene A process for creating interconnects by first etching trenches into
a layer of insulation and then filling them with a conducting material. Commonly
used for copper interconnects on integrated circuits.
Data dependency A dependency between instructions using the same regis-
ters or memory locations. True data dependencies are caused by one instruction
using the result of another, a read-after-write dependency. False data depend-
encies are caused by instructions waiting to write to locations being used by other
instructions, write-after-read or write-after-write dependencies.
DCA Direct chip attach.
Deadlock When forward progress cannot be made in a program because mul-
tiple instructions are waiting for each other to complete.
Decoupling capacitors (Decaps) Capacitors added to an integrated circuit die
or package to reduce supply noise.
Defects per million (DPM) The number of defects per million parts shipped.
DeMorgan’s theorem A theorem of boolean logic stating that any function is
equal to the same function with all ANDs changed to ORs, all ORs changed to
ANDs, and all terms inverted.
Design automation engineer An engineer responsible for the creation and/or
maintenance of CAD tools used in design.
Design for test (DFT) circuits Circuits used specifically to help detect manu-
facturing defects. These circuits are also commonly used to help in silicon debug.
Device limited layout Layout where the area required is determined prima-
rily by the number of transistors and their sizes. See wire limited layout.

DFT Design for test.
Die paddle The portion of the leadframe for a plastic package to which the die
will be attached. Also called a flag.
Die separation The manufacturing step where a wafer is cut into individual die.
Die side cap (DSC) Decoupling capacitors placed on the same side of the pack-
age substrate as the die.

Die yield The percentage of functional die on each completed wafer.
Diffusion region A region where N-type or P-type dopants have been added
to a semiconductor to create free charge carriers.
Diode A circuit element allowing current to flow in only one direction. Typically
formed by a single P-N junction.
DIP Dual in-line package.
Direct chip attach (DCA) Attaching a bare integrated circuit die directly to a
printed circuit board. Also called chip on board (COB).
Direct mapped cache A cache memory that stores each memory address in a
single location.