Ellipsometric end point detection during plasma etching

Abstract

This paper will describe the use of an ellipsometric method for end point detection during plasma etching at different stages of thin film sensor processing and IC processing. End point detection of an area as small as 3.7 × 10-3cm2(24 × 24 mil2) was achieved by utilizing a commercial ellipsometer which was slightly modified. The method does not require the use of dummy wafers or of backside protected wafers. In addition to end point detection, the method can also be used for in situ etch rate determination of insulating and metallic films as a function of RF power, chamber pressure, temperature, load size, and type of etching gas.