| 摘要 |
<p>PURPOSE:To make it possible to align a wafer at a prescribed position without exceeding a detection extent even if a wafer height detector, which has the narrow detection extent, is used by a method wherein a height control deviation generated due to an encoder servo system, which makes a poor response, is, corrected by a magnetic sensor servo system which makes a good response. CONSTITUTION:An encoder servo system 52 is subjected to proportional, integral and differential control to constitute a positioning control system and at the same time, a magnetic sensor servo system 54 is subjected to proportional control to constitute a positioning control system and the two control systems are actuated simultaneously with the movement in the horizontal direction of a stage.</p> |
