Abstract: Chamfering C1 is performed along the edge of a notch groove by the center 01 of a grindstone 5. Change to grindstone center 02 is performed to perform chamfering C2 along the edge of the notch groove. Similarly, chamfering C3, C4 and C5 are formed. A grindstone having a large diameter can be employed. Only control of the diameter of the grindstone is required to maintain the shape. Satisfactory surface roughness can be realized. It is possible to improve surface roughness of a notch groove of a wafer and realize high efficiency.

Abstract: A workpiece 23 formed of a circular thin plate is rotated about its center as an axis L1. Each of disk-shaped rotating grinding wheels 27 and 28, while being rotated about an axis L3 extending in a direction substantially parallel to the plane of the workpiece 23 and perpendicular to the radial direction of the workpiece 23, is made to undergo relative feeding movement on both obverse and reverse surface sides of the workpiece 23 along an outer peripheral edge portion 23a of the workpiece 23. Consequently, the outer peripheral edge portion 23a of the workpiece 23 is ground by an outer peripheral surface of each of the rotating grinding wheels 27 and 28. In this case, it is preferred that two grinding wheels 27 and 28 for rough grinding and finish grinding be provided as the disk-shaped rotating grinding wheels, and that rough grinding and finish grinding are performed by the same station.