IC Knowledge - Glossary

Glossary of Integrated Circuit Terminology - U

ULPA - Ultra Low Particle Air - a type of air filter that removes 99.999% of particles 0.12µm or larger.
ULSI - Ultra Large Scale Integration - integrated circuits containing greater than 10 million transistors.
Ultrapure Chemicals - chemicals low in particles and contaminants.
Ultrapure Gases - gases low in contaminants such as moisture and other gases.
Ultrapure Water - highly purified water, low in ions, particles, organic matter and colloids.
Ultrasonic - a wirebond process using ultrasonic energy to form wirebonds.
Ultraviolet Light - electromagnetic waves with a wavelength of 10 to 700 nanometers. See also near ultraviolet light, mid ultraviolet light and deep ultraviolet light.
Undercut - etching underneath the edge of a layer. Occurs during isotropic etching.
Unexposed - an area of photoresist that has not interacted with radiation.
Unipolar - a semiconductor that uses only one type of carrier for conduction - either holes or electrons.
UPW - see Ultrapure Water.
Utilization - the actual hours a tool is producing product divided by the scheduled production hours for the tool.
UV - see Ultraviolet Light