Dry etching method

Abstract

A dry etching method, wherein a multilayer film including one selected from tungsten, molybdenum, and a silicide thereof, as the first layer, and polycrystal silicon as the second layer underlying is formed on a silicon oxide insulation film, a substrate having a mask pattern on the multilayer film is placed in a vacuum container, an etching gas is introduced into the vacuum container, and an electrical discharge is induced by applying an electrical field to the vacuum container, thereby anisotropically etching the multilayered film in accordance with the mask pattern. The method comprises the first etching step for etching the first layer by use of the first gas selected from fluorine, sulfur hexafluoride, and nitrogen trifuoride, or a mixture gas containing the first gas and the second gas selected from hydrogen chloride, hydrogen bromide, chlorine, bromine, and carbon tetrachloride, as an etching gas, and the second etching step for etching the second layer by use of the second gas, or a mixture gas containing the second gas and the third gas selected from an inert gas, nitrogen gas, oxygen gas, silicon tetrachloride gas and carbon monoxide gas, as an etching gas.