Electrostatic Charge Generation on Wafer Surfaces and its Effect on Particulate Deposition

Abstract

Semiconductor fabrication processes involving contact and separation of processing media with wafer surfaces can leave a wafer electrostatically charged. It was shown theoretically that the electrostatic charge may have an effect on the rate of particle deposition on exposed wafer surfaces. In this paper the results of the experimental studies of static charge generation on wafer surfaces and particle deposition on charged wafers in semiconductor manufacturing environment are presented. It was observed that in a very clean environment of the Class 10 cleanroom the effect of electrostatic potentials of up to 6000 volts applied to the wafers on the rate of > 1 µm particle deposition on the wafer surfaces could not be demonstrated, while the effect was statistically significant in a less clean environment of the Class 10,000 cleanroom.