INFORMATION MEDIUM MASTER MANUFACTURING METHOD, INFORMATION MEDIUM STAMPER MANUFACTURING METHOD, INFORMATION MEDIUM MASTER MANUFACTURING APPARATUS, AND INFORMATION MEDIUM STAMPER MANUFACTURING APPARATUS

摘要

An information medium master manufacturing method includes a step of forming a latent image by applying an exposure beam to a photoresist layer (13) formed on a light absorbing layer (12), a step of performing development so as to expose a part of the light absorbing layer (12) from the photoresist layer (13), a step of dry etching the light absorbing layer (12) by using the photoresist layer (13) as a mask so as to form a concave portion in the light absorbing layer (12), and a step of removing the photoresist layer (13) from the light absorbing layer (12) so as to obtain a master (1) having a convex/concave pattern. The light absorbing layer (12) is formed by such a resin material that the etching rate selection ratio of the photoresist layer against the etching rate of the light absorbing layer (12) during the dry etching is 0.5 or above. By this, even when a concave portion (2) of a desired depth is completed, the photoresist layer (13) as a mask can remain, so as to prevent rounding or shallowing of the groove shape of the concave portion (2). Thus, it is possible to manufacture an information medium master having a sharp convex/concave pattern.