"Today we have to stop a fab line to perform non-destructive light-scattering tests to determine if any particles have settled on wafers, potentially causing short-circuits. But the particle blaster can detect and analyze particles in real-time without stopping the line," said William Reents, a member of Bell Labs' Process and Chemical Engineering Research Department, and the inventor of particle blaster.

Conventional light-scattering techniques fail to analyze a particle's composition, other than its approximate size, said Reents, whereas the particle blaster determines the size of a particle as well as its precise atomic composition.

Capable of detecting particles as small as one-thousandth of a micron, the particle blaster can determine the total weight of a particle and the relative percentages of the atomic elements of which it is composed.

"We think that the particle blaster will help us to extend the limits of semiconductor processing technologies, as well as advance the sensitivity limits of our characterization tools," said Reents.

Transistors are approaching the sub-0.10-micron range, which virtually obsoletes conventional light-scattering particle-detection techniques. The particle blaster can assist the process of detection by working continuously in real-time. In addition, if any particles of the "wrong" type are detected, alarms can alert fab personnel, rather than waiting for a postmortem analysis.

"It brings particles under the focus of a high-powered pulsed laser, which then blasts the particle apart," said Reents.

Breaking a particle into an ionized plasma of about 1011 atoms lets mass-spectrometer techniques be applied to determine its relative composition.

Bell Labs is testing the particle blaster on its own fab lines. It hopes eventually to apply the particle blaster to further applications, such as analyzing trace particles in otherwise pure manufacturing chemicals or analyzing submicron pollutants.

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