US Patent 7462094 Wafer grinding method

A wafer grinding method is disclosed, in which only a region, corresponding to a device formation region, of the back side of a wafer is ground in rough grinding conducted first, while the part surrounding the region thus ground is left unground as an annular projected part, to prevent the outer peripheral edge of the wafer from becoming knife edge-like in shape. In the subsequent finish grinding, the annular projected part is ground and, further, the whole area of the back side of the wafer is ground to be flat. Chippings of the outer peripheral edge may be generated only during the finish grinding, whereby the chippings are prevented from occurring or limited to minute ones.