| 摘要 |
<p>PURPOSE:To enhance the stepping accuracy of a wafer stage regarding a projection aligner in a semiconductor field, especially regarding the control circuit of the wafer stage. CONSTITUTION:A servodrive circuit 1 which drives and controls a wafer stage 16 is constituted so as to provide a control circuit in which two bidirectionally acting diodes 2 are added to a feedback circuit 4 for a servoamplifier 3 which gives a driving voltage to a motor 11.</p> |
