Page 398 - A Practical Guide from Design Planning to Manufacturing

368 Glossary

Instructions per cycle (IPC) The average number of instructions completed per
cycle. Overall processor performance is determined by the product of clock fre-
quency and IPC.
Insulator A material containing few or no free charge carriers preventing it
from conducting electricity under normal conditions.

Integrated circuit (IC) An electronic circuit containing multiple components all
made from a single piece of semiconductor. Modern integrated circuits can con-
tain more than a billion transistors.

Integrated heat spreader (IHS) A metal plate in an integrated circuit package
designed to spread out heat generated by the die.
Interlevel dielectric (ILD) Insulating material deposited between levels of
interconnect in an integrated circuit.
Internal lead The part of a package lead inside the die encapsulation.
Interrupt Temporary suspension of the execution of a program to run an inter-
rupt handler pointed to by a global address table. Software interrupts are caused
by the execution of an interrupt instruction. Hardware interrupts are triggered
by signals from external devices. Interrupts allow subroutines that are inde-
pendent of the program currently being run to be called to handle special events.
Inversion layer A layer of free charge carriers beneath the gate oxide of a
MOSFET of the opposite type of the transistor’s well. This layer is created by
the gate voltage in the linear and saturation regions of operation.
Ion implantation The addition of dopant atoms to a semiconductor by ioniz-
ing the element to be added and accelerating it through an electric field at the
surface of a wafer.
IP Instruction pointer.
IPC Instructions per cycle.
IREM Infrared emissions microscope.
Isotropic etch An etch that proceeds at the same rate in all directions.
J-bend pin A package pin that bends inward.
Jump instruction An instruction that always redirects program flow to new
instruction address.
Karnaugh map (K-map) An aid to by hand logic minimization.
kB kilobyte

Keeper device A transistor used only to prevent a wire’s voltage from chang-
ing when no other transistor is driving it. Keeper devices are sized very small
to allow other transistors to easily override them when the wire’s voltage needs
to be changed.
Keyhole void A hole in the material of a via caused by a deposition step that
fails to fill narrow gaps fully.