Abstract: Disclosed is a method for removing an oxide film formed on a surface of a silicon wafer, comprising steps of: preparing a silicon wafer having an oxide film formed thereon; arranging a discoid wafer mounting stage, which has a contact portion with the oxide film being formed of an acid-resistant resin layer, in a reaction container of a vapor-phase etching apparatus; mounting the silicon wafer on the mounting stage in such a manner that a wafer center coincides with a central axis of the mounting stage; and circulating a hydrogen fluoride containing gas into the reaction container and removing the oxide film from an interface between a chamfered surface and a wafer lower surface toward the inner side of the wafer until a desired interval a is obtained, wherein the desired interval a is adjusted by changing a stage diameter of the mounting stage.