Disc master, disc master manufacturing method, stamper, disc substrate, optical disc, and optical disc manufacturing method

摘要

In a process of manufacturing a disc master, a stamper, a disc substrate, and an optical disc, separation performance between the stamper and the disc substrate and maintenance of satisfactory signal characteristics after the optical disc is manufactured are taken into consideration in the step of manufacturing the disc master. In the disc master, a boundary portion between a recessed portion and a non-recessed portion includes a small protrusion which protrudes from a flat surface of the non-recessed portion. The shape of the disc master is inversely transferred to the stamper, and the shape of the stamper is inversely transferred to the disc substrate. The separation performance is improved and the signal characteristics are maintained due to the shape of the boundary portion.