Patent ID: 7795114

Claim:
A manufacturing method of an SOI substrate, comprising the steps of: arranging a plurality of single crystalline semiconductor substrates over a fixing substrate to form a first seed substrate; arranging a second seed substrate over the first seed substrate so as to be bonded to the first seed substrate, wherein the second seed substrate is formed by a plurality of single crystalline semiconductor substrates each having a first separation layer which is formed by introduction of ions in a region at a predetermined depth from a surface of the second seed substrate; conducting heat treatment in a state in which the first seed substrate and the second seed substrate are overlapped; generating a crack in the first separation layer of the second seed substrate, and separating a part of the second seed substrate such that a plurality of first single crystalline semiconductor films are left over the first seed substrate; forming a second single crystalline semiconductor film by epitaxial growth so as to cover the first single crystalline semiconductor films and a gap between the first single crystalline semiconductor films; forming a second separation layer by introduction of ions in a region at a predetermined depth from a surface of a third single crystalline semiconductor film including the first single crystalline semiconductor films and the second single crystalline semiconductor film; attaching a substrate having an insulating surface to the third single crystalline semiconductor film; conducting heat treatment in a state in which the third single crystalline semiconductor film and the substrate having the insulating surface are overlapped; and generating a crack in the second separation layer, and separating the fixing substrate, the first seed substrate, and a part of the third single crystalline semiconductor film from the substrate having the insulating surface so that a fourth single crystalline semiconductor film is left over the substrate having the insulating surface.