Patent ID: 7614934
Filing Date: 2009-11-10
Classification: B24B

Abstract:
1. A double-side polishing apparatus for polishing upper and lower faces of a wafer, comprising: a lower polishing plate having an upper face capable of acting as a polishing face; an upper polishing plate having a lower face capable of acting as a polishing face; a frame holding said upper polishing plate above said lower polishing plate, said frame capable of moving said upper polishing plate in a vertical direction; a carrier being provided between said lower polishing plate and said upper polishing plate, said carrier having a through-hole, in which the wafer is held; a plate driving unit for rotating said lower polishing plate and said upper polishing plate about their axes; a carrier driving unit for rotating said carrier; and a slurry supply unit, wherein said lower polishing plate, said upper polishing plate and said carrier are rotated while supplying slurry to said lower polishing plate so as to polish the upper and lower faces of the wafer, a window section, through which a laser beam passes, is formed in a part of said upper polishing plate, under which the wafer held by said carrier passes, an optical thickness measuring equipment is provided to a part of said frame, the window section of said, upper polishing plate passing under the optical thickness measuring equipment while said upper polishing plate is rotated, and said thickness measuring equipment being adapted to emit the laser beam through the window section, to receive reflected beams reflected from an upper face and a lower face of the wafer, and to calculate a thickness of the wafer based on peak values of the reflected beams.