Patent ID: 8485866

Claim:
A substrate holding apparatus, comprising: a top ring body for holding and pressing a substrate against a polishing surface, said top ring body having an upper member and a lower member; a retainer ring portion having a retainer ring body arranged so as to contact the polishing surface and hold an outer circumferential edge of the substrate during a polishing process, said retainer ring portion being vertically movable with respect to said top ring body; and a retainer ring pressing mechanism for pressing only said retainer ring portion against the polishing surface during the polishing process by supplying a pressurized fluid to a retainer pressure chamber, wherein said retainer ring pressing mechanism includes an elastic membrane arranged so as to define said retainer pressure chamber, and a piston connected to a lower end of said elastic membrane, wherein the piston is a separate element from said retainer ring portion, and the piston cooperates with the retainer ring portion to press the retainer ring body against said polishing surface, wherein said lower member of said top ring body and said retainer ring portion comprise a carrier assembly and are arranged to be separated as a unit from said upper member of said top ring body and said piston of said retainer ring pressing mechanism.