Patent ID: 7776718

Claim:
A method for manufacturing a semiconductor substrate, comprising the steps of: forming a first brittle layer by adding hydrogen ions to a first single-crystalline semiconductor substrate; bonding the first single-crystalline semiconductor substrate and a substrate having an insulating surface to each other; separating the first single-crystalline semiconductor substrate by heat treatment using the first brittle layer as a separation plane such that a first single-crystalline semiconductor layer with a thickness d is left remaining over the substrate having the insulating surface; forming a second brittle layer by adding hydrogen ions to a second single-crystalline semiconductor substrate which is formed using the same material as that of the first single-crystalline semiconductor substrate; bonding the second single-crystalline semiconductor substrate and the substrate having the insulating surface to each other such that the second single-crystalline semiconductor substrate partly overlaps with the first single-crystalline semiconductor layer; separating the second single-crystalline semiconductor substrate by heat treatment using the second brittle layer as a separation plane such that a second single-crystalline semiconductor layer with a thickness d is left remaining over the substrate having the insulating surface; forming a resist so as to cover the first single-crystalline semiconductor layer and the second single-crystalline semiconductor layer; and patterning the resist by irradiation with laser light of a wavelength λ, wherein, when an extinction coefficient of the first single-crystalline semiconductor layer and the second single-crystalline semiconductor layer is represented by k, the thickness d of the first single-crystalline semiconductor layer and the second single-crystalline semiconductor layer and a penetration length δ of the laser light satisfy d≦δ<5d (δ=λ/4πk).