A dry etching method for use in the manufacture of a semiconductor integrated circuit using an etching apparatus which is provided with an exciting chamber into which a reactive gas is introduced and an etching chamber which communicates with the reactive gas exciting chamber in which a substrate to be etched is placed, wherein the reactive gas is excited by microwave energy and then the excited reactive gas is introduced into the etching chamber where the excited reactive gas is re-excited by light energy, preferably of the wavelength of the range 180-400 nm, where the re-excited reactive gas is passed over the substrate during the etching thereof.