Patent ID: 6852019

Claim:
A substrate holding apparatus for holding a substrate to be polished and pressing the substrate against a polishing surface, said substrate holding apparatus comprising: a top ring body for holding a substrate; an elastic pad for being brought into contact with the substrate; a support member for supporting said elastic pad; a contact member mounted on a lower surface of said support member and disposed in a space formed by said elastic pad and said support member, said contact member having an elastic membrane for being brought into contact with said elastic pad; a first pressure chamber defined in said contact member; a second pressure chamber defined outside of said contact member; a fluid source for independently supplying a fluid into, or creating a vacuum in, said first pressure chamber and said second pressure chamber; and a retainer ring, fixed to or integrally formed with said top ring body, for holding a peripheral portion of the substrate, said retainer ring defining a central opening and having a through hole extending through said retainer ring from an outer surface to an inner surface of said retainer ring.