shown in FIG. 10A. The type of etching gas to be used in the plasma etching is not herein specified, and a gas including fluorocarbon may be used.Then, the organic film 15 is subjected to plasma etching using plasma generated from the etching gas used in the etching method for any of Embodiments 1 through 5, namely, an etching gas including, as a principal constituent, a mixed gas of amolecule in