Flow control of process gas in semiconductor manufacturing
Patent 6450200 Issued on September 17, 2002. Estimated Expiration Date: 
February 6, 2022. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
February 6, 2022. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 975838 1620322 2545787 3279495 Method and apparatus for flow metering Pressure-reducing regulator valve for high-pressure gases Method and apparatus for measuring and controlling volumetric flow rate of gases in a line Fluid pressure regulator Metal diaphragm valve Intelligent mass flow controller InventorAssigneeApplicationNo. 066659 filed on 02/06/2002US Classes:137/624.12, With independent valve controller73/1.35, With pressure measurement or plural flowmeters137/486, Responsive to change in rate of fluid flow137/487, Control by pressures across flow line valve137/487.5Electrically actuated valveExaminersPrimary: Chambers, A. MichaelAttorney, Agent or FirmForeign Patent References
International ClassesG05D 007/06F16K 031/12 AbstractA flow control system and method for controlling batchwise delivery of process gas for semiconductor manufacturing are disclosed, wherein the flow control system is operable in a flow mode for delivery of a batch of process gas in a delivery period of time and, alternately, in a no-flow mode. After the start of the delivering, the pressure drop of the gas in a reference capacity of the system is measured for a measurement period of time while interrupting the flow of process gas from a source of the process gas to the reference capacity and continuing to deliver process gas from the system to a semiconductor manufacturing apparatus at a controlled flow rate. The rate of pressure drop in the reference capacity during the measurement period of time is used as a measure of the actual flow rate. Where the actual flow rate does not agree with a specified flow rate for delivering, the controlled flow rate for a subsequent delivery period of time in which another batch of process gas is delivered, is adjusted. Components of the flow control system are arranged along a gas manifold in the form of an elongated delivery stick having a width of less than 1.5 inches, saving important space in a group of the flow control systems that may comprise up to 20 units.Other References
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