Patent ID: 6506097
Filing Date: 2003-01-14
Classification: B24B,H01L

Abstract:
A method of polishing a substrate, comprising:chemical mechanical polishing a first layer of substrate with a first polishing fluid, the substrate having a second layer disposed under the first layer, the first and second layers having differing reflectivity; optically monitoring the substrate during polishing with the first polishing slurry 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 the first layer, chemical mechanical polishing the substrate with a second polishing fluid having different polishing properties than the first polishing fluid; continuing to optically monitor the substrate during polishing with the second polishing slurry; and halting polishing after all the intensity traces indicate that the second layer has been completely exposed.