Patent ID: 7156719

Claim:
A polishing apparatus comprising: a polishing table having a polishing surface thereon; a top ring for pressing a workpiece against said polishing surface, said top ring having a housing and a retainer ring vertically movable in said housing for holding an outer circumferential edge of the workpiece; a vertically moving mechanism operable to vertically move said top ring; a bracket vertically movable together with said top ring; a stopper adjustable in vertical position to prevent downward movement of said bracket; a sensor for detecting a distance between said stopper and said bracket; and a control unit operable to adjust said stopper in vertical position when said retainer ring is brought into contact with said polishing surface while a lower surface of said housing of said top ring is located at a predetermined height from said polishing surface so that the distance between said stopper and said bracket is equal to a difference between a height of the lower surface of said housing from said polishing surface at the time of polishing and said predetermined height.