Method for manufacturing SOI substrate and method for manufacturing semiconductor device

摘要

A highly reliable semiconductor device capable of high speed operation is manufactured over a flexible substrate at a high yield. A separation layer is formed over an insulating substrate by a sputtering method; the separation layer is flattened by a reverse sputtering method; an insulating film is formed over the flattened separation layer; a damaged area is formed by introducing hydrogen or the like into a semiconductor substrate; an insulating film is formed over the semiconductor substrate in which the damaged area is formed; the insulating film formed over the insulating substrate is bonded to the insulating film formed over the semiconductor substrate, the semiconductor substrate is separated at the damaged area so that a semiconductor layer is formed over the insulating substrate; the semiconductor layer is flattened so as to form an SOI substrate; and the semiconductor device is formed over the SOI substrate.