Semiconductor Manufacturing: No Tresspassing

As computers get smaller and smaller, contamination becomes a bigger issue in manufacturing them. Even the vacuum chambers used in “clean rooms” aren’t completely free of wayward particles-and even tiny particles can ruin an expensive set of silicon wafers.

Existing defenses against these trespassers aren’t particularly sharp. They work by periodically checking the surfaces of silicon wafers for impurities. These methods are hit-and-miss, and they’re helpless against particles smaller than two-tenths of a micrometer.

Now William Reents, a chemist at Lucent Technologies’ Bell Labs, has put together a laser-based instrument to zero in on particles as small as one-thousandth of a micrometer, a twohundredfold improvement. What’s more, the device can determine in real time the chemical composition of the contamination, helping pinpoint its source.