An oxide film etching method includes: forming a protective film of a metal or a metal nitride that does not contain silicon so as to cover a protection target film, among the protection target film containing silicon and a silicon-containing oxide film exposed on a surface of a substrate; supplying, to the substrate, a mixed gas including a hydrogen fluoride gas and an ammonia gas to react with the silicon-containing oxide film, and modifying the oxide film to generate a reaction product; and sublimating and removing the reaction product.

An oxide film etching method includes: forming a protective film of a metal or a metal nitride that does not contain silicon so as to cover a protection target film, among the protection target film containing silicon and a silicon-containing oxide film exposed on a surface of a substrate; supplying, to the substrate, a mixed gas including a hydrogen fluoride gas and an ammonia gas to react with the silicon-containing oxide film, and modifying the oxide film to generate a reaction product; and sublimating and removing the reaction product.