Dual detection method for end point in chemical mechanical polishing

摘要

A dual detection method for end point in a chemical mechanical polishing process is described. The dual detection method utilizes both an optical detection device and an acoustical detection device. The acoustical detection device may also be used independently in certain applications without the optical detection device. The acoustical detection device determines an end point and stops the CMP process when a volume of the acoustical emission changes by at least 30% from its initial volume, or preferably changes by at least 50% from its initial volume.