| 摘要 |
An electron beam lithography apparatus has a first chamber for holding a workpiece with the first chamber having an outer wall with an opening therein. A second chamber has an electron beam column mounted therein, with the second chamber positioned adjacent the first chamber and having an outer wall having a portion in common with the portion of the outer wall of the first chamber containing the opening. An electron beam column in the second chamber includes an aperture and generates an electron beam through the aperture and the opening at the workpiece. The apparatus includes a first pump for creating a vacuum in the first chamber, a second pump for creating a vacuum in the second chamber, a first vent for permitting gas to enter the first chamber for increasing the pressure in the first chamber, and a second vent for permitting gas to enter the second chamber for increasing the pressure in the second chamber. A balancing bypass valve in the common wall between the first and second chambers (i) operates in a first mode to permit gases to flow from the first chamber to the second chamber when the pressure in said second chamber exceeds the pressure in the first chamber, (ii) operates in a second mode to permit gases to flow from the second chamber to the first chamber when the pressure in the first chamber exceeds the pressure in the second chamber, and (iii) operates in a third mode to seal the first chamber from the second chamber when the pressures in the first and second chambers are equal.
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