Micro-electro-mechanical charge sensing devices

Plasmas are being widely used in the semiconductor industry for delineation of fine line pattern and deposition at low temperature. In recent years, it has been reported that plasma non uniformity across the wafer due to non-uniformities in RF current flow, electron current flow, and ion current flow can cause significant charging of surfaces, which can severely degrade or destroy devices, especially MOS gate dielectrics. In this work we report for the first time, a device which can non-invasively measure this charging in-situ, in real time, in the plasma reactor, as opposed to the conventional method of inferring the charge from later measurement of device degradation. The charging is measured in-situ by measuring the deflection of micro-cantilevers.