Patent ID: 8070909

Claim:
An apparatus for polishing substrates, comprising: at least one polishing station configured to polish a current wafer during a polishing process; and a controller, operatively coupled to the at least one polishing station, configured to control the polishing station during the polishing process, to receive data relating to material removal rates for a plurality of substantially annular regions on the wafer, to predict a material removal rate for each of the plurality of substantially annular regions using a wafer polishing model that is based on measurement of one or more previous wafers that have completed at least one step of the polishing process, wherein the wafer polishing model defines an effect of a tool state of the at least one polishing station on polishing effectiveness based on applying a scaling factor that depends on pad life and disk life, to calculate differences between the predicted material removal rates and actual material removal rates that are determined based on the received data, to update the wafer polishing model based on the calculated differences, and to adjust a processing parameter of the polishing process based on the updated wafer polishing model.