To avoid contamination and help maximize production yield, robots stationed in tracks along the ceiling are used to move these 300-mm chips between manufacturing steps. Courtesy Intel Corporation.
Today’s typical dime-sized semiconductor chip contains millions of microscopic transistors. On that ultrasmall scale the tiniest speck of dust in relation to the chip would appear as a dinosaur-sized footprint would to us. A speck of dust is enough to obstruct the chip’s many pathways, rendering it useless.
Semiconductor fabrication facilities, known as fabs, depend heavily on their specialized clean rooms to maintain a controlled, low level of environmental pollutants.
Clean rooms
Modern clean rooms rely on highly engineered systems developed by chemical engineers to capture, contain, and control dust, airborne microbes, and chemical vapors. The objective is to minimize drastically the level of contamination. These desired levels are typically specified in terms of the number of particles of a given size per cubic foot of air.
Complex, high-efficiency particle-arrestor filtration systems are typically used in fab clean rooms. The areas are pressurized with filtered air to remove even the smallest particles, which could come to rest on the wafers and contribute to defects. Protective clothing is worn by clean-room technicians more to protect the semiconductor devices from human contamination than the other way around.
Copyright © 2009 American Institute of Chemical Engineers and Chemical Heritage Foundation. All rights reserved.