| 摘要 |
<p>PURPOSE:To make it possible to detect efficiently the eccentric amount, eccentric position and eccentric direction of a wafer to the mounting position of the wafer and the position of an orientation flat by a method wherein detecting systems are arranged two groups in opposition to each other at 180 degrees centering around a roating shaft, on which the wafer is held, and an arithmetic processing is executed using two output signals from the detecting systems. CONSTITUTION:A wafer 7 having an orientation flat (a) on part of its outer periphery is rotatably held on a rotating shaft 8 and two detecting systems are arranged in opposition to each other at 180 degrees centering around the center (b) of rotation of the shaft 8. Moreover, the position of the orientation flat is operated on the basis of the angle of rotation of the shaft 3 at the time of generation of a signal using two output signals from the two detecting systems at the time of 1/2 rotation of the wafer 7. Moreover, the eccentric angle and the eccentric amount of the wafer 7 to the shaft 8 are operated on the basis of the output signals of the angles of rotation at the time of generation of the two output signals and the wafer 7 is positioned at a prescribed position on the basis of each operated value. Thereby, the wafer can be positioned at the prescribed position with high accuracy and at high speed.</p> |
