A process of forming, on a surface of the substrate a plurality of resist layers made of two kinds of dry film resist that differ in main peak wavelength in spectral photosensitivity. An exposure process of selectively exposing and affecting a particular resist layer in accordance with a first pattern upon using a first exposure mask overlaid on the plurality of resist layers. A second exposure process of exposing another resist layer in accordance with a second pattern upon using a second exposure mask overlaid on the plurality of resist layers. Partially uncovering the surface of the substrate by removing unexposed portions of the plurality of resist layers, to form a resist mask having an aperture. Finally, forming a coat layer by plating a portion of the substrate where the surface thereof is uncovered; and a process of removing the resist mask.