| 摘要 |
<p>PROBLEM TO BE SOLVED: To align the center of a semiconductor wafer and the positional angle (orientation flat) of a flat part accurately at the time of carrying the wafer. SOLUTION: Edge position of a wafer is detected and stored in correspondence with each rotational angle of a wafer rotating means under rotation. Assuming the edge position signals when the wafer rotating means is rotated by 90 deg., 180 deg. and 270 deg. from a rotation angle of detecting an edge position signal Lx1 are Lx2, Lx3 and Lx4, only four output signals Lx1-Lx4 of edge position signal are detected and stored from a time point when output of the edge position signals is stopped before the wafer rotating means rotates by one revolution. Since a CPU can be occupied in the operation before the wafer rotating means rotates by one revolution and the CPU begins operation of the eccentricity Le and eccentric angleθe at the central position of the wafer, the eccentricity Le and eccentric angleθe of the wafer can be matched with high accuracy in a short time.</p> |
