Patent ID: 8038511

Claim:
A method for machining a chamfer portion of a semiconductor wafer that is a method for subjecting a roughly ground chamfer portion of a semiconductor wafer to helical grinding by relatively inclining the wafer and a second grinding stone to perform precise grinding, comprising: forming an edge portion of a discoid truer into a vertically asymmetrical groove shape of a first grinding stone by using the first grinding stone having a vertically asymmetrical groove formed on a periphery thereof to grind the edge portion of the truer without being relatively inclined; forming a groove on a periphery of the second grinding stone by relatively inclining the truer and the second grinding stone to subject the second grinding stone to helical grinding; and precisely grinding the chamfer portion of the wafer based on helical grinding by relatively inclining the semiconductor wafer with respect to a direction of the groove formed on the periphery of the second grinding stone.