Patent ID: 6695681
Filing Date: 2004-02-24
Classification: B24B

Abstract:
A system for polishing wafers and determining the endpoint of certain polishing procedures, where a polishing pad is secured to a platen, and the platen and polishing pad are rotated, and a surface of a wafer is held against a polishing area of the polishing pad to effect polishing of the surface, and at least a portion of the polishing pad is not used for polishing, said system comprising:a polishing pad having an optical window disposed on the pad, in the polishing area; an optical sensor disposed within the optical window, said optical sensor adapted to detect an optical characteristic of the wafer surface, said optical sensor being operable to output an electrical signal corresponding to the optical characteristic of the wafer surface; an inductive coupling system operable to inductively transfer signals from the pad during rotation to a stationary receiver, said inductive coupling system comprising a first transformer winding secured to the pad such that it rotates with the pad, and a second transformer winding within the stationary receiver, and a means to communicate the electrical signal output from the optical sensor to the first transformer winding.