Sony Corporation

Hitoshi Shimomuki

Toru Abiko

Fuminori Takase

Ayumi Konishi

Tomoki Kanesaka

Eiichi Shimizu

Fumio Sasaki

In order to ensure CAV recording/reproduction while preventing jitter deterioration and modulation decrease and thereby ensuring sufficient recording properties, even at a linear velocity higher than 4.8 m/s, a first dielectric film, phase change versatile recording film, second dielectric film, reflection film and protective film are formed on a disc substrate having formed lands and grooves on one major surface. The recording film is made of a GeInSbTe alloy, and the reflection film is made of an AgPdCu alloy or AlCu alloy. Composition of the GeInSbTe alloy is adjusted to contain Ge in the range of 1 to 6 wt %, In in the range of 2 to 6 wt %, and control Sb/Te in the range of 2.2 to 3.0. Composition of the AgPdCu alloy is adjusted to contain Cu not more than 1.5 wt %. Regarding groove conditions, groove depth is controlled in the range of 40 to 50 nm, groove width in the range of 0.40 to 0.65 &mgr;m, thickness of the first dielectric film in the range of 75 to 95 nm, thickness of the recording film in the range of 12 to 18 nm, thickness of the second dielectric film in the range of 20 to 28 nm, and thickness of the reflection film in the range of 60 to 140 nm.

Optical recording medium

In order to increase the recording capacity while preventing jitter deterioration and a decrease of the modulation factor and thereby ensuring satisfactory recording characteristics, a first dielectric film, phase recording film, second dielectric film, reflection film and protective film are sequentially formed on a disc substrate having formed lands, grooves and wobbling on one major surface. The recording film is made of a GeInSbTe alloy, and the reflection film is made of an AgPdCu alloy or AlCu alloy. Composition of the GeInSbTe alloy is adjusted to contain Ge in the range of 1 to 8 wt %, In in the range of 2 to 6 wt %, and control Sb/Te in the range of 2.2 to 3.0. Composition of the AgPdCu alloy is adjusted to contain Pd in the range of 0.9 to 1.5 wt % and Cu not more than 1.5 wt %. Composition of the AlCu alloy is adjusted to contain Cu in the not more than 1.5 wt %. Groove depth is controlled in the range of 35 to 45 nm, groove width in the range of 0.35 to 0.50 &mgr;m, thickness of the first dielectric film in the range of 75 to 95 nm, thickness of the recording film in the range of 12 to 20 nm, thickness of the second dielectric film in the range of 16 to 28 nm, and thickness of the reflection film in the range of 80 to 160 nm.

In order to ensure CAV recording/reproduction while preventing jitter increase and modulation decrease and thereby ensuring sufficient recording properties, even at a linear velocity in the range of 3.49 to 8.44 m/s, a first dielectric film, phase-versatile recording film, second dielectric film, reflection film and protective film are formed on a disc substrate having formed lands, grooves and wobbling on one major surface. The recording film is made of a GeInSbTe alloy, and the reflection film is made of an AgPdCu alloy or AlCu alloy. Composition of the GeInSbTe alloy is adjusted to contain Ge in the range of 1 to 6 wt %, In in the range of 2 to 6 wt %, and control Sb/Te in the range of 2.4 to 3.0. Composition of the AgPdCu alloy is adjusted to contain Cu not more than 1.5 wt %. Groove depth is controlled in the range of 30 to 40 nm, groove width in the range of 0.27 to 0.33 &mgr;m, thickness of the first dielectric film in the range of 65 to 80 nm, thickness of the recording film in the range of 12 to 18 nm, thickness of the second dielectric film in the range of 12 to 20 nm, and thickness of the reflection film in the range of 80 to 160 nm.

A method for producing a sputtering target assembly consisting of a target member used for sputtering and a backing plate bonded to the target member, which assembly has a high adherence strength and a high bonding strength as well as a sufficient tensile strength even under a high temperature. When producing a sputtering target assembly consisting of a target member used for sputtering and a backing plate bonded to the target member, bonding surfaces of the target member and the backing plate are made flat so as to have an arithmetic mean roughness Ra of 0.01 to 1.0 .mu.m before carrying out solid phase diffusion bonding between the target member and the backing plate.

Growing community of inventors

Miyagi, Japan

Hitoshi Shimomuki