PURPOSE: To form accurately fine grooves on an optical disc substrate or the like in a short time, by using anacrylic polymer degradably by far-ultraviolet rays capable of forming required grooves by selective irradiation of the far- ultraviolet rays.
CONSTITUTION: A substrate is made of a polymer degradable by far-ultraviolet rays such as polymethyl methacrylate, hexafluorobutyl methacrylate and grooves for an optical disc is formed by irradiating the far-ultraviolet rays on the substrate by contact exposure through a mask with fine pitches, or by scanning and exposing a laser beam of far-ultraviolet rays without the mask. A metal such as Te is vapor-deposited on the grooved side of the substrate to obtain the optical disc and the substrate for a master stamper. Since pitches and withds of the grooves can be controlled by the mask and the beam, and depths of the grooves can be controlled by the irradiation time and the light intensity, arbitrary grooves can be formed accurately in a short time.
KAWAZU TAKAHARU
YAMASHITA YOSHIO
