Patent ID: 7510948

Claim:
A method for producing an SOI wafer, comprising ion-implanting a noble gas element in an active layer wafer via an insulating film to form an ion-implanted layer in the active layer wafer; subsequently bonding the active layer wafer with a supporting wafer via the insulating film disposed therebetween to form a bonded wafer; and then performing heat treatment on the bonded wafer while holding the bonded wafer at a set temperature so as to cleave and separate a part of the active layer wafer at a site of the ion-implanted layer as an interface, and controlling the heat treatment so that temperature variation within a surface of the bonded wafer is 40Â° C. or less so as to achieve the cleavage at the site of the ion-implanted layer as the interface by positioning a plurality of heat sources, laterally with respect to a top surface and a back surface of the bonded wafer, so that the heat sources uniformly heat the surface of the bonded wafer.