Reflecting film for optical information recording medium, and sputtering target for forming reflecting film for optical information recording medium

Abstract

The present invention provides an Al-based alloy reflecting film which reduces noise on an optical information recording medium by having a reflecting film surface accurately reproduce grooves, pits and the like formed on a substrate, and has high reflectivity. A sputtering target which is effective for forming such a reflecting film is also provided. The reflecting film to be used for the optical information recording medium is substantially composed of an Al-based alloy containing 2.0-15.0 atm% of a rare-earth element, and has a crystallite size of 30 nm or smaller in the thickness direction of the reflecting film.

Description

Technical field [0001] The present invention relates to optical information recording media such as DVD-ROM, DVD-R, DVD+R, DVD-RW, DVD+RW, DVD-RAM, BD (Blu-ray Disc)-R, BD-RE, BD-ROM, etc. Reflective films and sputtering targets used to form these reflective films. Background technique [0002] Optical information recording media (optical discs) can be roughly classified into read-only type (for example, DVD-ROM, BD-ROM), write-once type (for example, DVD-R, DVD+R, BD-R), and There are three types of rewritable (for example, DVD-RW, DVD+RW, BD-RE, DVD-RAM). [0003] Among them, for example, a read-only optical information recording medium has a configuration in which a reflective film mainly composed of Ag, Al, etc., and a light transmission layer are sequentially laminated on a substrate such as a transparent plastic. In addition, the reflective film and the light-transmitting layer are basically formed every other layer, but it is also known to have a structure formed every sec...

AI Technical Summary

Problems solved by technology

[0008] In the chemical composition shown in the technique, although the reflectance of the reflective film is high, the crystallite size (crystal grain size) does not necessarily decrease, and the surface of the reflective film cannot reproduce the grooves or pits formed on the substrate with high precision. The problem

If this is the case, the noise of the optical information recording medium using the reflective film is large, and good signal quality cannot be obtained.

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