METHOD AND APPARATUS FOR DETECTING POLISHING ENDPOINT WITH OPTICAL MONITORING

摘要

An apparatus, as well as a method, brings a surface of a substrate into contact with a polishing pad that has a window, causes relative motion between the substrate and the polishing pad, and directs a light beam through the window so that the motion of the polishing pad relative to the substrate causes the light beam to move in a path across the substrate. An extreme intensity measurement is derived from a plurality of intensity measurements made as the light beam moves across the substrate. The beam sweeps across the substrate a plurality of times to generate a plurality of extreme intensity measurements, and a polishing endpoint is detected based on the plurality of extreme intensity measurements.