PURPOSE: To enable resolution and signal S/N at the reproducing of an information recording medium using laser light to be improved by recording and forming undulation patterns having shapes of high accuracy on the recording tracks of a substrate such as glass substrate.
CONSTITUTION: A first metal thin film layer 11 such as of Zn and a second metal thin film layer 12 such as of Al are formed on a substrate 10. Next, recording laser light 15 having been modulated according to recording information is focused and radiated by a lens system onto the layer 12 of the substrate 10 rotating at a specified speed, and the heat energy thereof causes the metal of the radiated regions to melt and evaporate, thereby recording undulation patterns 13 having pits 13a on the recording tracks of the layer 12. Next, when the substrate 10 is dipped in a concentrated nitric acid applied with ultrasonic waves, the layer 12 surface becomes passive and the regions of the layer 11 exposed by the pits 13a are selectively removed with the layer 12 as a mask, whereby the second undulation patterns 14 in correspondence to the pits 13a are recorded and formed. Next, the substrate 10 is dipped in NaOH solution, whereby the layer 12 is removed.
ENDOU ATSUSHI
YOSHIDA YURI
