Process for fabrication of semiconductor device, semiconductor wafer for use in the process and process for the preparation of the wafer

摘要

In a process for the fabrication of a semiconductor integrated circuit using a double-side mirror-polished wafer or the like, at the portion of a notch 10 of a notched wafer 1, a chamfered angle theta11 of the first chamfered portion 11 formed at the inner periphery of the first primary surface 3 is set smaller than the chamfered angle theta12 of the second notch chamfered portion 12 of the second primary surface 4 and the chamfered width L11 is set larger than the chamfered width L12, whereby the obverse and reverse of the wafer are discriminated by optically discriminating the first notch chamfered portion and the second notch chamfered portion using reflected light, thereby making it certain to fabricate IC on the surface of the wafer and to use the reverse for its handling. The plane view of the notch in the circumferential direction can be maintained symmetrical so that the lowering in the symmetry of the wafer and the number of the IC available from the wafer can be prevented and the standards of the notch can be maintained.