| abstract |
Irradiating a resist film with a wavelength of 195 nm or less to form a resist pattern having a minimum line width of 200 nm or less, and then dry etching the resist pattern using a fluorine-based compound having 4 to 6 carbon atoms having at least one unsaturated bond as an etching gas. Dry etching method consisting of. As the fluorine-based compound, perfluoro-2-pentine, perfluoro-2-butyne, nonafluoro-2-pentene and perfluoro-2-pentene are preferably used. Perfluoro-2-pentine is reacted with 1,1,1-trihalo-2,2,2-trifluoroethane and pentafluoropropionaldehyde to give 2-halo1,1,1,4,4, 5,5,5-octafluoro-2-pentene was produced, and the resulting 2-halo-1,1,1,4,4,5,5,5-octafluoro-2-pentene was dehydrogenated. By treatment. |