Patent ID: 7654883

Claim:
A method of wafer polishing comprising a coarse polishing step and a final polishing step, in which, a polishing liquid is interposed between a polishing target material and an abrasive cloth while the polishing target material held by a chuck is pushed against the abrasive cloth, polishing of the polishing target material is implemented by the abrasive cloth by a relative motion of the chuck and a polishing plate, wherein a retainer ring is vertically movable in a periphery of the chuck, and a pushing force of the retainer ring against the abrasive cloth is set in accordance with the polishing step, the polishing in a coarse polishing step is implemented when the abrasive cloth is pushed by the retainer ring, the retainer ring is retracted upward during transition from the coarse polishing step to a final polishing step, and the polishing in a final polishing step is implemented when the retainer ring is retracted form the abrasive cloth.