Patent ID: 8278187

Claim:
A method for manufacturing a single crystal semiconductor film, the method comprising: oxidizing a surface of a single crystal semiconductor substrate to form an insulating film over the single crystal semiconductor substrate; irradiating the single crystal semiconductor substrate with ion beam through the insulating film; bonding the single crystal semiconductor substrate with a base substrate having an insulating surface; separating the single crystal semiconductor substrate from the base substrate to allow a thin film of the single crystal semiconductor substrate and the insulating film to be left on the base substrate; performing a first etching treatment on a remaining single crystal semiconductor substrate, which is separated from the base substrate in the separation step, with a first etchant containing hydrofluoric acid, ammonium fluoride, and a surfactant; and then performing a second etching treatment on the remaining single crystal semiconductor substrate with a second etchant containing hydrofluoric acid, nitric acid, and acetic acid.