| 摘要 |
<p>PURPOSE:To reduce power consumption during service interruption by using a pump having at least necessary evacuating performance. CONSTITUTION:The vacuum suction operation of a wafer chuck 4 and wafer hand 10 is driven by both a main pump 15 and backup pump 58. Their evacuating performance depends on the size of wafer, coefficient of friction on the suction surface, resistance of throttle valve, distance between the chuck 4 and hand 10 at the time of delivery of the wafer 5, etc. Present example necessitates a vacuum suction performance enough to evacuate up to a lower pressure by 100Torr than that within a stage housing chamber 1. However, the delivery operation for the wafer 5 is stopped during service interruption, so the evacuating performance of the pump 58 is set as to generate a lower pressure by 20Torr than that within the chamber 1. Therefore, the power consumption during service interruption can be reduce.</p> |
