MATERIAL FOR PROTOTYPE ALUMINUM MOLD FOR STAMPER, PROTOTYPE ALUMINUM MOLD FOR STAMPER, AND STAMPER

摘要

Disclosed is a material for prototype aluminum mold for stamper, characterized by having a composition, which comprises 0.5-3.0 mass% of Mg, not more than 500 ppm in total of elements, including unavoidable impurities, other than Mg, and the balance being Al, and a cast structure wherein the average crystal grain diameter is 1000 µm or less and the area ratio of secondary phase grains is 0.10% or less. By miniaturizing aluminum crystal grains, preventing the formation of secondary phase grains and smoothening irregularities caused by mirror polishing, a stamper having a uniform peak-and-valley pattern that is formed by anodization can be obtained.