Etching method and plasma processing apparatus

Abstract

An etching method includes: (a) preparing a substrate including a silicon-containing film including a silicon oxide film and placed on a substrate support provided in a chamber; (b) supplying a processing gas containing a tungsten hexafluoride gas, a gas containing carbon and fluorine, and an oxygen-containing gas into the chamber; and (c) generating plasma from the processing gas to etch the silicon-containing film. (c) includes periodically applying a negative DC voltage to the substrate support.