Patent ID: 7662239

Claim:
A method of producing group 3 nitride substrate wafers comprising the steps of: preparing a plurality of group 3 nitride substrate wafers having a diameter of 40 mm or more and an orientation flat OF having a length of 2 mm to 30 mm; gluing a plurality of group 3 nitride substrate wafers on a bottom of a circular polishing plate with a thermoplastic wax having a thickness of 10 μm or less in a direction of the OF facing forward (f), backward (b) or inward (u) with regard to rotation of the polishing plate; and planar-processing surfaces of the group 3 nitride substrate wafers into mirror surfaces with a bevel of a horizontal width (e) less than or equal to 200 μm and a vertical depth (g) less than or equal to 100 μm.