Patent ID: 8338270

Claim:
A method for manufacturing an SOI substrate comprising the steps of: forming an oxide film on a single crystal semiconductor substrate; introducing accelerated ions into the single crystal semiconductor substrate through the oxide film to form an embrittled region in the single crystal semiconductor substrate; bonding a supporting substrate such that the supporting substrate and the single crystal semiconductor substrate face each other with the oxide film interposed therebetween; forming a single crystal semiconductor layer bonded to the supporting substrate by heating the single crystal semiconductor substrate and performing separation at the embrittled region; performing first etching on a surface of the single crystal semiconductor layer bonded to the supporting substrate; after performing the first etching, irradiating the single crystal semiconductor layer with a laser beam and melting and solidifying at least part of the surface of the single crystal semiconductor layer; and after irradiating the single crystal semiconductor layer, performing second etching on the surface of the single crystal semiconductor layer using a plasma with no substrate bias applied.