Patent ID: 8314006

Claim:
A method for manufacturing a bonded wafer with a first substrate and a second substrate attached, the first substrate having a reduced film thickness on the second substrate, the method comprising at least the steps of: forming an ion-implanted region by implanting a hydrogen ion or a rare gas ion, or the both types of ions from a surface of the first substrate which is a semiconductor substrate; subjecting at least one of an ion-implanted surface of the first substrate and a surface of the second substrate to a surface activation treatment; laminating the ion-implanted surface of the first substrate and the surface of the second substrate in an atmosphere with a humidity of 30% or less or a moisture content of 6 g/m3 or less to make a laminate, wherein the laminating is carried out in such a way that any one point on the substrates is defined as a lamination starting point and that the point is pressed to slide the substrates so as to keep out air while rotating the substrates in a circular motion with the point as a center of rotation; and splitting the first substrate at the ion-implanted region so as to reduce thickness of the first substrate, thereby manufacturing a bonded wafer with a film on the second substrate.