US Patent 9613823 Etching method and storage medium

An etching method includes disposing a target substrate within a chamber. The target substrate has a first silicon oxide film formed on a surface of the target substrate by a chemical vapor deposition method or an atomic layer deposition method, a second silicon oxide film that includes a thermally-oxidized film and a silicon nitride film. The second silicon oxide film and the silicon nitride are formed adjacent to the first silicon oxide film. The etching method further includes supplying an HF gas and an alcohol gas or water vapor into the chamber to selectively etch the first silicon oxide film with respect to the second silicon oxide film and the silicon nitride film.