| 摘要 |
PURPOSE:To produce the information recording medium of high performance by etching a substrate by the use of active gasseous chemical species with the metal thin film provided on the substrate and carrying information as a mask then covering the surface thereof with a metal layer of high reflectance. CONSTITUTION:The Al layer 6 of about 400Angstrom in thickness provided on a glass plate (substrate) 1 is selectively cut by using modulated laser light 4 to constitue spiral information tracks of about 0.8mu in width and 1.6mu in pitch to form pits (Fig. A, B). Next, with the Al layer 6 having been produced with the abovementioned pits as a mask, the glass plate 1 is etched by using active gasseous chemical species to make the depth about 1200 to 1100Angstrom (Fig. C), thence a metal layer 13 such as Cr is deposited to about thickness 600Angstrom on the surface of the glass plate 1 (Fig.E). It is desirable to perform the process of the abovementioned Fig. C by using a parallel electrode type dry etching apparatus and the gasseous chemical species obtained by applying high frequency voltage to gas such as S3F8 under vacuum of about 10<-2> torr. |
