Patent ID: 9663857
Date: 2017-05-30
CPC Classifications: C23C,Y10T

Claim:
1. A method for stabilizing pressure of a reaction chamber during a process using a first gas and a second gas, wherein a gas inlet line is connected to the reaction chamber, and a second gas line and a first gas line are connected to another end of the gas inlet line, said method comprising: feeding a first gas in pulses according to a waveform to the reaction chamber through the first gas line and the gas inlet line; and feeding a second gas in pulses according to a reverse waveform to the reaction chamber through the second gas line and the gas inlet line, wherein superimposed waveforms of the waveform and reverse waveform are made substantially flat, thereby stabilizing pressure of the reaction chamber, wherein the first gas line has a main line and a branch line branched off from the main line upstream of the other end of the gas inlet line, the second gas line has a main line and a branch line branched off from the main line upstream of the other end of the gas inlet line wherein the main line of the first gas and the main line of the second gas are merged to the other end of the gas inlet line, and the branch line of the first gas line and the branch line of the second gas line are merged to a vent line for discharging gas by bypassing the reaction chamber, wherein the waveform is formed by switching the main line and the branch line of the first gas by using a valve provided in the branch line of the first gas between the branching point in the first gas line and the merging point in the vent line and a valve provided in the main line of the first gas between the branching point in the first gas line and the merging point with the second gas line in a vicinity of the merging point with the second gas line, whereas the reverse waveform is formed by switching the main line and the branch line of the second gas by using a valve provided in the branch line of the second gas between the branching point in the second gas line and the merging point in the vent line and a valve provided in the main line of the second gas between the branching point in the second gas line and the merging point with the first gas line in a vicinity of the merging point with the first gas line, wherein mass flow in the first gas line is regulated by a mass flow controller upstream of the branching point, mass flow in the second gas line is regulated by a mass flow controller upstream of the branching point, and flow in the vent line is controlled by a fixed throttle downstream of the merging point, wherein the first gas continuously flows through the mass flow controller for the first gas, and the second gas continuously flows through the mass flow controller for the second gas without mixing the first and second gases in the gas inlet line and the vent line.