Patent ID: 6632124
Filing Date: 2003-10-14
Classification: B24B,H01L

Abstract:
A polishing system comprising:a polishing surface; a carrier to hold a substrate against the polishing surface; a motor to move at least one of the polishing surface and the carrier head to generate relative motion between the polishing surface and substrate; a dispensing system to dispense a first polishing fluid and a second polishing fluid; an optical monitoring system; and a computer configured to cause the polishing system to chemical mechanical polish a first layer of substrate with the first polishing fluid, optically monitor the substrate during polishing with the first polishing fluid to generate plurality of intensity traces, with each intensity trace including intensity measurements from a different radial range on the substrate, once any of the intensity traces indicates an initial clearance of a first layer on the substrate, chemical mechanical polish the substrate with a second polishing fluid having different polishing properties than the first polishing fluid, continue to optically monitor the substrate during polishing with the second polishing fluid, and halt polishing after all the intensity traces indicate that a second layer beneath the first layer has been completely exposed.