Patent ID: 7955874

Claim:
A method of producing a bonded silicon wafer comprising: a step of implanting oxygen ions from one surface of a silicon wafer for active layer to form an oxygen ion implanted layer at a given depth area from the one surface of the silicon wafer for active layer; a step of bonding the one surface of the silicon wafer for active layer to one surface of a silicon wafer for support layer with or without an insulating layer and then conducting a heat treatment for strengthening the bonding to form a silicon wafer composite; a step of polishing a silicon portion at a side of the silicon wafer for active layer in the silicon wafer composite on a rotating platen having a polishing means and stopping the polishing at a time of detecting change of physical properties on the rotating platen resulting from the exposure of at least a part of the oxygen ion implanted layer; and a step of removing the oxygen ion implanted layer, wherein the change of physical properties is a change of friction resistance produced between the polishing means and a polished surface of the silicon wafer composite, wherein the friction resistance is measured by a rotation torque applied to the rotating platen, and wherein the silicon wafer composite is polished by making rotation number of the rotating platen different before and after the polishing stop.