Patent ID: 8496022

Claim:
A device for supplying gas divided to a chamber from a gas supply facility equipped with a flow controller, the device comprising: (a) a gas supply device disposed to supply a specified quantity of gas, while dividing the specified quantity of gas at a specified flow rate ratio Q 1 /Q 2 from the gas supply facility provided with the flow controller, into the chamber through a plurality of branch supply lines, wherein the plurality of branch supply lines include a first branch supply line and a second branch supply line, and wherein shower plates are fixed to ends of the first branch supply line and the second branch supply line; (b) a first open/close valve and a second open/close valve that are installed on the first branch supply line and the second branch supply line, respectively; (c) a first bypass line that is disposed on a downstream side of the first open/close valve and branched from the first branch supply line; (d) a second bypass line that is disposed on a downstream side of the second open/close valve and branched from the second branch supply line; (e) a pressure type division quantity controller that is connected to the first bypass line and the second bypass line, wherein the pressure type division quantity controller controls flow rate in the first branch supply line and in the second branch supply line; (f) a first pressure sensor that is disposed to measure pressure inside the first branch supply line; (g) a second pressure sensor that is disposed to measure pressure inside the second branch supply line, wherein Q 1 and Q 2 are specified quantities of gas supplied to the first branch supply line and the second branch supply line, respectively; and (h) a control device disposed to regulate a degree of opening of the pressure type division quantity controller in order to reduce a difference between actual pressure of one of the plurality of branch supply lines and a set pressure to reach the specified flow rate ratio Q 1 /Q 2 by comparing either one of a first set pressure or a second set pressure, respectively, of the first branch supply line and the second branch supply line to reach the specified flow rate ratio Q 1 /Q 2 with corresponding first actual pressure or second actual pressure of the first branch supply line and the second branch supply line measured by the first pressure sensor or the second pressure sensor, wherein the control device is connected to receive pressure signals from the first pressure sensor and the second pressure sensor, and the control device is connected to send control signals to the pressure type division quantity controller and to a switch valve, a wherein the control device is operable to determine values for Q 1 and Q 2 when given a total flow quantity Q and the specified flow rate ratio Q 1 /Q 2 , wherein the specified flow rate ratio Q 1 /Q 2 has a value in the range of 4/1 to 1/4.