Patent ID: 7989305

Claim:
A method for manufacturing a semiconductor device, the method comprising: a first step of forming a separation layer in a first surface of a semiconductor wafer by irradiating the first surface of the semiconductor wafer with a cluster ion while the first surface of the semiconductor wafer is inclined at about 6°±4° with respect to a vertical direction; a second step of bonding the first surface of the semiconductor wafer and a substrate, over which an insulating layer is formed, to each other with the insulating layer interposed therebetween; a third step of separating the first surface of the semiconductor wafer at the separation layer or at a region near the separation layer to form a separation wafer having a separation plane and a silicon-on-insulator substrate which includes a semiconductor layer formed over the substrate; a fourth step of treating the separation wafer having the separation plane so as to make the separation plane of the separation wafer flat; and a fifth step of performing the first to fourth steps using the separation plane of the separation wafer as the first surface of the semiconductor wafer of the first to third steps, wherein a second surface of the semiconductor wafer opposes to the first surface of the semiconductor wafer, and wherein the semiconductor wafer is used only the first surface of the semiconductor wafer.