Patent ID: 7488240
Filing Date: 2009-02-10
Classification: B24B

Abstract:
1. A polishing device comprising: a polishing pad for polishing a wafer; and a polishing head for holding the wafer, said polishing head including a retainer ring for retaining the wafer in an in-plane direction of the wafer, a membrane sheet for pressing the wafer against said polishing pad, and a head body for supporting said retainer ring and said membrane sheet, wherein: said retainer ring includes a first retainer member having an inner edge for retaining a peripheral surface of the wafer and having a thickness substantially equal to a thickness of the wafer, and a second retainer member for supporting a peripheral portion of said first retainer member; and said membrane sheet has a diameter larger than a diameter of the wafer and presses said inner edge of said first retainer member in addition to the wafer.