Patent ID: 6210482
Filing Date: 2001-04-03
Classification: C23C,F17D,G05D,H01L,Y10T

Abstract:
An apparatus for feeding gases for use in semiconductor manufacturing facilities comprising a plurality of gas supply sources, gas source valves provided on gas lead-out pipes from said respective gas supply sources, a flow rate controller provided on a main gas feed pipe into which the lead-out pipes converge, and a gas feed valve provided on an outlet side of the flow rate controller;wherein the flow rate controller is a pressure-type flow controller comprising:a control valve provided on the main gas feed pipe;a pressure detector provided on a downstream side of the control valve;a plurality of orifices provided on the downstream side of the pressure detector in parallel;a flow rate calculation circuit for calculating the flow rate Qc given by the equation Qc=KP1 from the pressure P1 found by said pressure detector and the constant K;a flow rate setting circuit for outputting a flow setting signal corresponding to a set gas flow rate; anda calculation control circuit for outputting to a drive of the control valve a control signal comprising the difference between said calculation flow rate and the flow rate setting signal; andwherein the control valve is operable to bring the control signal to zero, thereby to control the flow rates on the downstream sides of the plurality of orifices and at the same time to select an orifice with a bore that matches the set gas flow rate out of said plurality of orifices and to actuate the orifice so selected.