Patent ID: 6106662
Filing Date: 2000-08-22
Classification: B24B,B24D

Abstract:
An apparatus for use in a chemical mechanical polishing system to generate an endpoint signal in the polishing of films on a semiconductor wafer surface, the chemical mechanical polishing system being configured to cause a relative motion between a polishing pad and the wafer surface during a polishing process, the apparatus comprising:a light source configured to generate light of a predetermined bandwidth;a fiber optic cable assembly having a first end and a second end, wherein the fiber optic cable is configured to propagate light from the light source to the wafer surface through a through-hole in the polishing pad, the first end of the fiber optic cable assembly extending partially into a through-hole in the polishing pad;a light sensor coupled to the second end of the fiber optic cable assembly, wherein the light sensor is configured to receive light reflected from the wafer surface through the fiber optic cable assembly and generate data corresponding to a spectrum of the reflected light; anda computer coupled to the light sensor, wherein the computer is configured to generate the endpoint signal as a function of the data from the light sensor.