| abstract |
The bonding surfaces of an active wafer and a support wafer have fitting faces each composed of a part of a spherical surface of the same curvature. The bonding surfaces of the wafers are superimposed on one another and bonded. As a result, the non-bonded areas around circumference of the bonded wafer is made small, and the planarity application area can be increased. Therefore, the yield of the bonded SOI wafers becomes high, thereby reducing chipping, wafer separation in the wafer processings. |