Patent ID: 8088299
Filing Date: 2012-01-03
Classification: B24B

Abstract:
1. A method of polishing a substrate comprising: mounting a substrate on a carrier head of a chemical mechanical polishing apparatus so that a first side of the substrate is adjacent to the carrier head, the carrier head including a base portion, a retaining ring and a flexible membrane to provide a mounting surface for the substrate and define a plurality of chambers; applying different pressures to the plurality of chambers to create regions of different pressure on the substrate; providing a substantially monotonic transition between different pressures in adjacent regions comprising dividing a volume between the flexible membrane and the base portion into the plurality of chambers with a flap that extends from an inner surface of a central portion of the flexible membrane and includes a laterally extending first section and an angled second section extending beneath the first section and connecting the laterally extending first section to the central portion; and polishing the substrate using a polishing pad contacting a second side of the substrate on a side opposite from the first side of the substrate.