Patent ID: 8002607

Claim:
A polishing apparatus comprising: a polishing section having a polishing pad and a holding member for holding a wafer, the polishing section being provided for polishing the wafer held by the holding member by applying a pressure between said polishing pad and the wafer while moving said polishing member relative to the wafer; a retainer ring attached to said holding member, the retainer ring having a supporting surface for supporting at least part of a portion of said polishing pad which extends off the wafer during polishing of the wafer; a pressure adjusting mechanism for adjusting a pressure on the supporting surface of said retainer ring; and a control unit for controlling said pressure adjusting mechanism to bring the pressure on said supporting surface of said retainer ring to a desired pressure using information based on a roll off quantity of the wafer, the roll off quantity being a set of distances between a reference line and points on a surface to be polished of the wafer, the reference line passing a reference point and being substantially parallel to the surface to be polished of the wafer.