US Patent 6991514 Optical closed-loop control system for a CMP apparatus and method of manufacture thereof

For use with a chemical mechanical polishing apparatus for polishing a semiconductor wafer having a platen, a polishing pad and a wafer carrier, an optical closed-loop control system. In one embodiment, the system includes a plurality of optical probes impacting a corresponding probe window and rigidly mountable through the platen. The system also includes a flash lamp configured to provide light to each of the plurality of optical probes and minimize an exposure time of the light onto the semiconductor wafer, a spectrograph configured to spatially image light received by each of the plurality of optical probes to a common charge-coupled device and produce real-time spectral reflectometry data therefrom. The system further includes a control subsystem configured to analyze the real-time spectral reflectometry data and determine at least one wafer state parameter therefrom, and cause the polishing to be adjusted based upon the at least one wafer state parameter.