PURPOSE: To simplify the process by a method wherein a window is opened by forming the first mark layer on a semiconductor substrate, and the second mask layer is formed on an electrode constituent layer which have been formed on the first mark layer by including the inside of the window.

CONSTITUTION: A resist film 6 is formed on a semiconductor substrate 1, and the window 7 is formed. The peripheral edge 8 of this window 7 is so formed as to become acute. Next, a metallic layer 9 is formed on the resist film 6 by including the inside of the window 7, and the second resist film 10 of required pattern is formed thereon; then, a metallic electrode 9a is formed by etching the metallic layer 9 by using this resist film 10 as a mask. Thereafter, the resist film 6 and the second resist film 10 are removed, resulting in the formation of a mushroom metallic electrode 9a. This manner enables the formation of a mushroom metallic electrode only by a time of etching and without lateral etching.