| 摘要 |
PURPOSE:To conduct the detection of the position of an orientation flat and the positioning of the orientation flat based on the detection of the position thereof precisely by obtaining the position of a perpendicular drawn to the orientation flat from the center of the revolution of a wafer. CONSTITUTION:One detecting point 6 is formed in the passing region of an orientation flat 4 at a time when a wafer 2 is turned, and a detecting sensor is fitted at the detecting point 6. The orientation flat 4 passes through the detecting point 6 at a position B first with the rotation of the wafer 2, and passes through the detecting point 6 again at a position C. When the angle of rotation of the wafer 2 during that time is represented by gamma, an angle gamma/2 displays the angle of the perpendicular 3 of the position B or C to a line 5 tying the center O of revolution and the detecting point 6. When a position D is represented as a predetermined position where the orientation flat 4 must be positioned and an angle between the perpendicular 3 and the line 5 at the position is represented by theta, the wafer 2 may be turned only by an angle of theta+gamma/2 from the position B in order to position the orientation flat 4 at the position D. |
