MOLD MANUFACTURING METHOD AND ELECTRODE STRUCTURE FOR USE THEREIN

摘要

Proposed are a method for very efficient anodic oxidation of an aluminum film formed on a substrate having a large area and an electrode structure used in this method. A method for manufacturing a moth eye mold includes (a) a process for forming a porous alumina layer having fine depressions by anodic oxidation by an electrode (32a) in contact with the surface of an aluminum film (10a), (b) a process for enlarging the fine depressions by placing the porous alumina layer in contact with an etching fluid after process (a), and (c) a process for enlarging the fine depressions by further anodic oxidation after process (b). The aluminum film is formed from aluminum having a purity of at least 99.99% by weight. The electrodes comprise a first electrode (32a1) formed from aluminum having a purity of no more than 99.50% by weight and a second electrode (32a2) which is formed from aluminum having a higher purity than that of the first electrode and is positioned between the surface and the first electrode. Processes (a) and (c) are conducted when the second electrode is in contact with the surface in the electrolytic fluid.