PURPOSE: To provide an etching method that obtains anisotropic shapes after etching, is highly selective against silicon oxide films, and is applicable to VLSI miciomachining techniques.

CONSTITUTION: The title method is for dry etching equipment wherein gas is introduced into an etching chamber, the gas is turned into plasma, and polycrystalline silicon films 102 are etched. A gas containing halogen is used for the etching operation. After a part of the lower layer film has been exposed on the surface of a wafer 104, the wafer is exposed in an O2 atmosphere, O2 plasma or H2O plasma. The polycrystalline silicon film 102 is etched again in the etching chamber. Thus a sufficiency of the remaining lower layer film, a very thin silicon oxide film 103, is ensured and anisotropy is achieved.