Patent ID: 9441791
Filing Date: 2016-09-13
CPC Classification: C23C,F17D,G05D,H01J,H01L,Y10T

Claim Text:
1. An etching gas supply unit for supplying at least a first etching gases and a second etching gas to a processing chamber of a plasma etching apparatus, the etching gas supply unit comprising: a plurality of first gas supply sources, each of which accommodates one of the first etching gases; a second gas supply source accommodating the second etching gas; a mixing portion to mix the first etching gases to make a gaseous mixture of the first etching gases; a multiplicity of branch flow passages to branch the gaseous mixture and supply the branched gaseous mixtures; a pressure control unit provided at each of the branch flow passages to adjust gas flow rates of the branched gaseous mixtures in the branch flow passages; a second etching gas supply passage to supply the second etching gas to at least one of the branch flow passages to which the second etching gas supply passage is connected; and a controller configured to control the following steps of: supplying the gaseous mixture of the first etching gases to the branch flow passages via the mixing portion; controlling a pressure ratio of the branched gaseous mixtures to be a specified pressure ratio by adjusting the pressure control units provided at the branch flow passages such that opening degrees of respective valves in the pressure control units are fixed under a condition in which the second etching gas is not supplied to any branch flow passage and, then, fixing the opening degrees of the valves; supplying the second etching gas at a specified flow rate to said at least one of the branch flow passages to which the second etching gas supply passage is connected while the opening degrees of the valves remained fixed; and injecting the first etching gases and the second etching gas toward the processing chamber.