Provided is a method for producing an SOI substrate comprising a
transparent insulating substrate and a silicon film formed on a first
major surface of the insulating substrate wherein a second major surface
of the insulating substrate which is opposite to the major surface is
roughened, the method suppressing the generation of metal impurities and
particles in a simple and easy way. More specifically, provided is a
method for producing an SOI substrate comprising a transparent insulating
substrate, a silicon film formed on a first major surface of the
transparent insulating substrate, and a roughened second major surface,
which is opposite to the first major surface, the method comprising steps
of: providing the transparent insulating substrate, mirror
surface-processing at least the first major surface of the transparent
insulating substrate, forming a silicon film on the first major surface
of the transparent insulating substrate, and laser-processing the second
major surface of the transparent insulating substrate so as to roughen
the second major surface by using a laser.