| 摘要 |
A method of and apparatus for controlling pressure in a process chamber having a continuous gas inlet flow and a continuous gas outlet flow comprising providing a pulsed valve at a gas outlet, a pressure gauge, and a programmable controller and varying the pulse rate of the pulsed valve, wherein either the open time or closed time, or both open and closed times, is lengthened or shortened, depending on whether the gauge pressure is above or below the programmed setpoint. |
