Etching method and plasma treatment device

Abstract

The present invention is an etching method comprising the following steps: (a) preparing a substrate on a substrate support, the substrate having a silicon-containing film and a mask on the silicon-containing film, the mask having a sidewall defining at least one opening that exposes the silicon-containing film; and (b) generating plasma from a processing gas containing hydrogen fluoride gas and a bromine-containing gas, the step comprising forming a first protective film containing bromine up to the lower portion of the sidewall and forming a recess in the silicon-containing film.

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