| abstract |
A method of etching capable of, when an organic material film is etched with the use of an inorganic material film as a mask, effecting etching with an excellent etching configuration while maintaining a high etching rate in correspondence to an etching pattern, at an excellent in-plane uniformity and without peeling of an inorganic material film. When an organic material film formed on an item to be treated is etched with the use of an inorganic material film as a mask by etching gas plasma in treating vessel (1), with respect to an etching pattern wherein the ratio, in terms of area ratio, of zone to be opened by etching is 40% or more, a mixed gas containing NH3 gas and O2 gas is used as an etching gas. On the other hand, with respect to an etching pattern wherein the ratio, in terms of area ratio, of zone to be opened by etching is less than 40%, NH3 gas is used as an etching gas. |