Method of controlling the duration of an endpoint polishing process in a multistage polishing process

Abstract

The present invention is directed to a method of controlling chemical mechanical polishing operations to control the duration of an endpoint polishing process. The method comprises providing a wafer having a layer of copper formed thereabove, performing a first timed polishing operation for a duration (t ) on the layer of copper at a first platen to remove a majority of the layer of copper, performing an endpoint polishing operation on the layer of copper at a second platen to remove substantially all of the layer of copper, determining a duration (t ) of the endpoint polishing operation performed on the layer of copper at the second platen, and determining, based upon a comparison between the determined duration (t ) of the endpoint polishing operation and a target value for the duration of the endpoint polishing operations, a duration (t ) of the timed polishing operation to be performed on a subsequently processed layer of copper at the first platen. In another embodiment, the invention further comprises modifying, based upon a variance between the determined duration (t ) of the endpoint polishing operation and a target value for the duration (t ) of the endpoint polishing operation, the duration (t ) of the timed polishing operation to be performed on a subsequently processed layer of copper at the first platen.