Etching method

摘要

An etching method etches an organic film by using an inorganic film as a mask at a high etch rate, in a satisfactory etch profile in a satisfactory in-plane uniformity without causing the inorganic film to peel off. An organic film formed on a workpiece is etched by using an inorganic film as a mask with a plasma produced by discharging an etching gas in a processing vessel ( 1 ). The etching method uses a mixed gas containing NH₃ gas and O₂ gas for etching the organic film when the organic film is to be etched in a pattern having an opening ratio of 40% or above. The etching method uses NH₃ gas as an etching gas for etching the organic film when the organic film is to be etched in a pattern having an opening ratio below 40%.