All plasma processes share a common problem that af- fects yield. Abnormal electric discharges can create par-ticulate matter and cause physical and/or electrical damage to the wafer. Such discharges can also cause the resulting plasma to be unstable. A group of researchers determined that they could effectively detect and suppress anomalous discharges in plasma equipment using the signals from two probes that can predict the occurrence of abnormal discharges. The discharges are then suppressed by controlling the voltage applied to the electrostatic chuck in a reactive ion etch (RIE) system. Reporting on their findings at the recent IEEE International Symposium on Semiconductor Manufacturing (ISSM 2005) were M. Yasa- ka (currently at the Ariake National College of Technology in Fukuoka, Japan) and colleagues with the Tokyo Cathode Lab (Kumamoto, Japan), NEC Electronics, the Kumamoto Industrial Research Institute and the Kyushu Institute of Technology.
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