| 摘要 |
PURPOSE:To enable to make a vacuum control valve in small-sized and light weight by a method wherein a part of a member for connecting an etching chamber to an exhaust pump is utilized as a conductance valve. CONSTITUTION:In case the etching chamber 1 is made vacuous for the purpose of purging gases therein, a hollow cylinder 6 is rotated by a drive motor 11 so that the conductance of the cylinder 6 becomes maximum. That is, the piston of a hole 5 in a main valve box 3 comes into exact coincidence with a cutout section of the cylinder 6. Next, a cover 8 of the main valve box 3 is opened and an exhaust air pump 12 is operated for a predetermined period of time to thereby evacuate the etching chamber at a high speed. Thus, a part of the member connecting the etching chamber 1 to the exhaust pump 12 is utilized as the conductance valve to thereby enable the size and weight of the valve to be reduced. |
