Patent ID: 6077385
Filing Date: 2000-06-20
Classification: B24B

Abstract:
A polishing apparatus for polishing a workpiece, said apparatus comprising:a turntable with a polishing cloth mounted on an upper surface thereof;a rotatable top ring for holding a workpiece and pressing the workpiece against said polishing cloth under a first pressing force to polish the workpiece, said top ring having a retaining portion for retaining an outer circumferential edge of the workpiece;a presser ring positioned outwardly of said retaining portion, said presser ring being vertically movable relative to said top ring, and said presser ring being rotatable independently of said top ring at a speed different than a speed of rotation of said top ring, such that relative rotation between said top ring and said presser ring being achieved; anda pressing device for pressing said presser ring against said polishing cloth under a second pressing force which is variable.