Abstract: A dry etching method of etching a material to be etched including a transition metal using an etching gas including a carbon oxide gas is provided. The carbon oxide gas may be carbon monoxide gas, carbon dioxide gas, or mixtures of these gases. The carbon oxide gas is preferably in accordance with the relationship "R=X/3 to 200X" where "X" is the ratio of the number of transition metal atoms to the total number of metal atoms and "R" is the ratio of the number of molecules of oxide of carbon to the number of halogen atoms. Such a dry etching is particularly preferably carried out when the material to be etched is aluminum-silicon alloy, the transition metal is copper, the etching gas is mixed gas of chlorine gas, boron trichloride gas and helium gas, and the carbon oxide gas is carbon monoxide.