Patent ID: 7056196
Filing Date: 2006-06-06
Classification: B24B

Abstract:
1. A wafer polisher which polishes a wafer by pressing the wafer against a polishing pad by a fluid layer, the wafer polisher comprising: a wafer holding head; a retainer ring which is attached to the wafer holding head and is in contact with the polishing pad; and a sheet material which is disposed inside the retainer ring, a plurality of through-holes being formed in the sheet material, wherein the fluid layer is formed between the wafer holding head and the wafer, and further comprising a back plate which is movably disposed inside the retainer ring and over the sheet material, means for exerting a force pressing the back plate toward the sheet material for increasing the pressure of said fluid layer, and means for equalizing the force pressing the back plate toward the sheet material and a back pressure acting on the back plate by the pressure of the fluid layer.