Patent ID: 8343849

Claim:
A method for manufacturing an SOI substrate comprising the steps of: forming an insulating film on a surface of a single crystal semiconductor substrate; forming an embrittlement region in the single crystal semiconductor substrate by irradiating the single crystal semiconductor substrate with an ion beam through the insulating film; etching a projection of a surface of a supporting substrate by a first plasma treatment; attaching the insulating film on the side of the single crystal semiconductor substrate, on which the embrittlement region is formed, and the etched surface of the supporting substrate; separating the single crystal semiconductor substrate in the embrittlement region by a heat treatment into the supporting substrate to which a single crystal semiconductor layer is attached, and part of the single crystal semiconductor substrate; irradiating the single crystal semiconductor layer with laser light after separating the single crystal semiconductor substrate; etching a surface of the single crystal semiconductor layer after irradiating the single crystal semiconductor layer; and performing a second plasma treatment on the surface of the single crystal semiconductor layer after etching the surface of the single crystal semiconductor layer; wherein the surface of the single crystal semiconductor layer is exposed to plasma including an OH free radical in the second plasma treatment.