Patent ID: 8349227

Claim:
A method of fabricating a mold that is for use in forming a motheye structure over a surface, the motheye structure including a plurality of first raised portions each having a two-dimensional size of not less than 10 nm and less than 500 nm when seen in a direction normal to the surface, the method comprising the steps of: (a) preparing an Al base in which an Al content is less than 99.99 mass %, the Al base containing not more than 10 ppm of an element whose standard electrode potential is higher than Al and not less than 0.1 mass % of an element whose standard electrode potential is lower than Al and giving an uneven shape to a surface of the Al base, the uneven shape including a plurality of second raised portions each having a two-dimensional size of not less than 0.1 μm and not more than 100 μm when seen in a direction normal to the surface (b) partially anodizing the Al base to form a porous alumina layer which has a plurality of very small recessed portions; (c) after step (b), allowing the porous alumina layer to be in contact with an etchant, thereby enlarging the plurality of very small recessed portions of the porous alumina layer; and (d) after step (c), further anodizing the Al base to grow the plurality of very small recessed portions.