Patent ID: 8314018

Claim:
A method for manufacturing a semiconductor device, comprising the steps of: forming a first insulating film over a surface of a first single-crystal semiconductor substrate; forming a second insulating film over a surface of a second single-crystal semiconductor substrate; forming a first embrittlement layer in the first single-crystal semiconductor substrate by a first ion doping through the first insulating film; forming a second embrittlement layer in the second single-crystal semiconductor substrate by a second ion doping through the second insulating film; bonding the first insulating film and the second insulating film to each other; forming a first single-crystal semiconductor film over the second single-crystal semiconductor substrate with the first insulating film and the second insulating film interposed between the first single-crystal semiconductor film and the second single-crystal semiconductor substrate by separating part of the first single-crystal semiconductor substrate along the first embrittlement layer by a first heat treatment; forming a third insulating film over the first single-crystal semiconductor film; bonding the third insulating film and an insulating substrate to each other; and separating part of the second single-crystal semiconductor substrate along the second embrittlement layer by a second heat treatment to form a second single-crystal semiconductor film over the insulating substrate with the third insulating film, the first single-crystal semiconductor film, the first insulating film, and the second insulating film interposed between the second single-crystal semiconductor film and the insulating substrate, wherein a dose of the first ion doping is higher than a dose of the second ion doping, and wherein a temperature of the first heat treatment is lower than a temperature of the second heat treatment.