Apparatus and method for pressure fluctuation insensitive mass flow control

  • US 6,932,098 B2
  • Filed: 03/23/2004
  • Issued: 08/23/2005
  • Est. Priority Date: 06/24/2002
  • Status: Active Grant
First Claim
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1. A system for providing a constant flow of gas into a vacuum processing chamber irrespective of fluctuations in pressure of a supply gas, comprising:

  • a mass flow controller comprising a mass flow sensor, including a sensor bypass, configured to sense the flow of the supply gas into an inlet of the controller, and a control valve for use in controlling the rate of flow of gas through an outlet of the valve;

    a pressures sensor configured to sense the gas pressure in a volume between the mass flow sensor bypass and the control valve; and

    an electronic controller configured to monitor the pressure sensed by said pressure sensor and to compensate the sensed inlet flow rate sensed by said mass flow sensor to thereby ensure substantially constant flow of gas from an outlet of the control valve irrespective of fluctuations in pressure of the supply gas.

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