PURPOSE: To improve resolution and signal S/N at the reproducing of an information recording medium using laser light by recording and forming undulation patterns having high accuracy on recording tracks of a substrate such as glass substrate or the like.
CONSTITUTION: An Al layer 11 is formed to about film thickness 400 on a glass substrate 10. Ar laser light 14 for recording having been modulated according to video information is focused by a lens system onto the recording tracks of the layer 11 and is radiated to the substrate 10 while it is being rotated at a specified speed. The heat energy thereof causes the Al of the layer 11 to melt and evaporated, thus recording and forming the first undulation patterns 12 having the pits 12a, 12b corresponding to the information beforehand on the recording tracks. Next, with this layer 11 as a mask, the substrate 10 is ion-etched by a parallel electrode type plasma dry etching apparatus, whereby the second undulation patters 13 having pits 13a, 13b of depths 1200 to 1600 corresponding to the patterns 12 are formed.
YADA TOSHIO
YOSHIDA YURI
