| 摘要 |
PROBLEM TO BE SOLVED: To obtain a substrate material having high ductility and high recording density with high mass-productivity by providing a surface protective film in an organic resin substrate with diamond-like carbon in which the number of pinholes is specified. SOLUTION: In a vacuum vessel 1, a high polymer substrate material 3 is fed in the direction of the arrow along a cylindrical can 7 by a feeding roll 2, and metallic atoms evaporated from an evaporating source 6 are deposited on the substrate material 3 to form a magnetic layer having about 0.15 to 0.18μm film thickness. Next, it is introduced into a vacuum vessel 9, the magnetic layer is subjected to plasma activating treatment and is moreover fed to a vacuum vessel 13, rare gas (such as helium or the like) containing a gaseous starting material (such as methane or the like) is fed from a gas introducing port 18 to generate plasma, and a hard carbon coating film consisting essentially of carbon is formed on the surface of the magnetic layer. In this way, a protective film composed of the hard carbon coating film having diamond-like carbon in which the number of pinholes is controlled to <=30 pieces/mm2 is obtd. The film thickness is controlled to 50 to 2000Å, preferably to about 100 to 500Å.
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