US Patent 7705430 Semiconductor wafer and processing method for same

A semiconductor wafer which is generally circular, and which has on its face an annular surplus region present in an outer peripheral edge portion of the face, and a circular device region surrounded by the surplus region, the device region having many semiconductor devices disposed therein. A circular concavity is formed in the back of the semiconductor wafer in correspondence with the device region, and the device region is relatively thin, while the surplus region is relatively thick.