In-situ absolute measurement process and apparatus for film thickness, film removal rate, and removal endpoint prediction

摘要

An apparatus and process for in-situ measurement of thin film thickness, ash rate, and end point generally include generating and measuring shallow angle interference patterns. The apparatus generally includes a chamber having a first viewing port and a second viewing port. The first viewing port includes receiving optics configured to receive light at a shallow angle from a surface of a substrate processed therein. The second port includes a broadband illumination source and is preferably disposed in a sidewall opposite the receiving optics. The process includes calculating the thin film thickness, ash rate, and end point from the interference patterns.