| 摘要 |
PURPOSE:To prevent treated products in a treating chamber from being broken down and contaminated by setting the initial flow rate of a fluid low, by increasing it gradually up to a desired value, and by controlling an exhaust control valve in the period so that pressure in the treating chamber reaches a prescribed value. CONSTITUTION:A controller 6 opens a displacement control valve fully by a control signal 9, sets a flow rate O with a flow setting signal 8, and drives an exhaust pump 1 with a driving signal 12 to discharge the 1st gas in a treating chamber 4. The exhaust state is detected by a pressure sensor 2 to be informed with its output signal 10 and when the pressure decreased below a certain value, the controller 6 sends a signal 8, indicating a fine flow rate, to a mass flow controller 5. The designated flow rate of the 2nd gas is supplied from an inlet 11 to the chamber 4, wherein the pressure rises. The signal 6 control the control valve 3 by a signal 9 to hold the prescribed pressure in the chamber 4. The controller 6 further increases the set flow rate to the mass controller 5 a certain time later, controls the control valve 3 so tht the pressure in the chamber 4 has the prescribed value, and further increases the flow rate of gas successively up to a desired flow rate. |
