| 摘要 |
<p>PROBLEM TO BE SOLVED: To solve the problem that conventionally the angle of rotation of an orientation flat is at times detected inaccurately, based on the shape and intensity of light reflected on the upper surface of a wafer near the orientation flat when the orientation flat is formed by mechanical grinding or polishing. SOLUTION: Light is applied to the side of the orientation flat of the wafer. A photodetector is provided, where the photodetector can detect the reflected light by a detection angle of at least±1 deg. to a wafer plane, an angle resolution of 0.05 deg. or less with respect to the wafer plane, and an angle resolution of 0.01 deg. or less in the circumferential direction of the wafer. A function is provided, where the function determines a reflected light detection angle in the circumferential direction of the wafer, where the integration intensity of the reflected light becomes the largest in a range where the inclination angle to the wafer plane is within a fixed angle.</p> |
