A method of dry etching, comprising exposing a resist film to radiation of 195 nm or less wavelength so as to form a resist pattern of 200 nm or less minimum line width and subjecting the resist pattern to dry etching using a fluorinated compound of C4-C6 having at least one unsaturated bond as an etching gas. Perfluoro-2- pentyne, perfluoro-2-butyne, nonafluoro-2-pentene and perfluoro-2-pentene are preferably used as the fluorinated compound. Perfluoro-2-pentyne can be synthesized by reacting a 1,1,1-trihalo-2,2,2-trifluoroethane with pentafluoropropylene aldehyde into a 2-halo-1,1,1,4,4,5,5,5-octafluoro-2- pentene and eliminating a hydrogen halide from this 2-pentene.
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