Abstract: A shallow notch 1 as a tentative mark is engraved on a periphery of an ingot at a position corresponding to a predetermined crystal orientation in the step of grinding the periphery of the ingot. After the ingot is sliced to wafers, a mark 2 for indication of a crystal orientation is carved on a sliced wafer at a position determined on the basis of the notch 1 by laser marking. Thereafter, the wafer is chamfered to a round shape, and the notch 1 is removed by the chamfering. Since a part where the mark 2 shall be carved is determined on the basis of the notch 1, the mark 2 is efficiently carved on the wafer without the necessity of subjecting each wafer to an X-ray analyzer.

Abstract: A pair of ring-shaped lapping plates 13, 23 are faced to both surfaces of a wafer 1. Each lapping plate 13, 23 has an outer diameter approximately equal to a radius of the wafer 1 and a lapping surface 14, 24 sliding in contact with the wafer 1. Each lapping plate 13, 23 is rotated along a direction reverse from the other, while an abrasion slurry A is fed into cavities 15, 25 of the lapping plates 13, 23 and discharged together with dusts separated from the wafer 1 through grooves engraved in the lapping surfaces 14, 24 and gaps between the wafer 1 and the lapping surfaces 14, 24. The lapping plate 23 is carried toward the stationary lapping plate 13 at a rate corresponding to abrasion of the lapping surfaces 14, 24. During lapping, the wafer 1 is rotated by drive rollers 31 and supported by guide rollers 32. In this way, both surfaces of the wafer 1 are simultaneously lapped.