| 摘要 |
A polishing apparatus has a polishing table ( 12 ) with a polishing surface ( 10 ) attached thereon, and a top ring ( 20 ) for pressing a workpiece (W) against the polishing surface ( 10 ). The top ring ( 20 ) has a housing ( 40 ) and a retainer ring ( 44 ) vertically movable in the housing ( 40 ) for holding an outer circumferential edge of the workpiece (W). The polishing apparatus includes a vertically moving mechanism operable to vertically move the top ring ( 20 ), a bracket ( 28 ) vertically movable together with the top ring ( 20 ), a stopper ( 32 ) adjustable in vertical position to prevent downward movement of the bracket ( 28 ), and a sensor ( 36 ) for detecting a distance between the stopper ( 32 ) and the bracket ( 28 ). The polishing apparatus also includes a control unit ( 34 ) operable to adjust the stopper ( 32 ) in vertical position when the retainer ring ( 44 ) is brought into contact with the polishing surface ( 10 ) while a lower surface of the housing ( 40 ) of the top ring ( 20 ) is located at a predetermined height from the polishing surface ( 10 ) so that the distance between the stopper ( 32 ) and the bracket ( 28 ) is equal to a difference between a height of the lower surface of the housing ( 40 ) from the polishing surface ( 10 ) at the time of polishing and the predetermined height. |
