PURPOSE: To make the line width of an electrode constant by a method wherein a metal electrode layer and a mask layer whose dry-etching selection ratio is good are used in order to eliminate a retreat of a mask during an anisotropic etching operation.

CONSTITUTION: An aluminum electrode layer 2 is applied to a silicon substrate or a silicon oxide film 1 on the substrate. A silicon oxide film layer is applied to the whole surface on the aluminum electrode layer 2. After that, a resist layer 4 is applied to the silicon oxide film layer. The silicon oxide film layer is etched anisotropically by making use of the resist layer 4 as a mask; a mask layer 5 is formed. The aluminum electrode layer 2 is etched to a halfway part by making use of the resist layer 4 as the mask, a remaining part of the aluminum electrode layer 2 is etched anisotropically by making use of the mask layer 5 as a mask.