. . . "The anodic oxides are grown a distance of 5000 ???. [0073] This anodic oxidation is carried out using an aqueous solution including 3% of oxalic acid as the electrolyte. [0074] At this step, the presence of the resist masks 205 and 206 causes the anodic oxidation to selectively proceed on side surfaces of the aluminum patterns 207 and 208." .