Patent ID: 9108289
Filing Date: 2015-08-18
Classification: B24B,B24D,H01L

Abstract:
1. A double-side polishing apparatus comprising: a lower turn table having a flat polishing-upper-surface that is rotationally driven; an upper turn table having a flat polishing-lower-surface that is rotationally driven, the upper turn table being arranged to face the lower turn table; a carrier having a wafer-holding hole configured to hold a silicon wafer to be polished; a plurality of openings provided between a rotation center and an edge of the upper turn table, the plurality of openings being equally spaced at a periphery of the upper turn table; and a wafer-thickness-measuring mechanism configured to measure a thickness of the silicon wafer through the plurality of openings by optical reflection interferometry during polishing in real time, the wafer-thickness-measuring mechanism being fixed to a housing of the double-side polishing apparatus and including a wavelength-variable-infrared laser having a wavelength of 1575 nm to 1775 nm that is transmittable through the silicon wafer to be polished.