摘要 |
In an apparatus for lapping a wafer material, e.g., a semiconductor silicon wafer, by bonding the wafer to the lower surface of a pressing plate, mounting the pressing plate on a turn table to bring the wafer into contact with the turn table and pressing the pressing plate downwardly with a downwardly opening cup-like top ring mounted thereon, the pressing plate is pressed down not directly with the top ring alone but pressed through a rubber membrane covering the downward opening of the top ring and pressurized with compressed air under pressure regulation so that the lapping pressure on the wafer surface can be very uniform and the thus lapped wafer is excellent in respect of the flatness of each lapped surface and parallelism between lapped surfaces.
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