PURPOSE: To increase heat resistance at low cost by using a highly heat-resistant resin which can withstand a temperature at the time of recording as a material for the formation of a pit on a substrate and making the bottom surface of this pit a surface of the substrate.
CONSTITUTION: A highly heat-resistant resin is formed by the depth of a pit on a glass substrate 1 using a rotating coating technique. Next, a photoregist (masking material) 3 is formed on the resin layer 2, and a pit 4 is formed using a laser exposure device (cutting device). Then a pit formed in the regist is transferred to the highly heat-resistant resin layer using a dry etching technique with the photoregist 3 as a masking material, and the regist 3 is removed. If polyimide resin is used, for example, at a regist-withstanding temperature (about 150°C), it has a heat resistant capability at about 300 to 400°C. In addition, the formed uneven bottom surface becomes a glass surface as a background so that it is effective for the reduction of a noise generated by the uneven bottom surface.
SONE KAZUNORI
TOKUJIYUKU NOBUHIRO
