Method for producing a master disk of a recording medium, method for producing a stamper, method for producing a recording medium, master disk of a recording medium, stamper of a recording medium, and recording medium

Abstract

A method for producing a master disk 105 for an optical disk 110 includes a layer forming step of forming a heat-sensitive material layer 102 on a substrate 101, an exposure step of exposing the heat-sensitive material layer 102 partially to a laser beam, and a pit and land pattern forming step of forming a pattern of pits and lands by means of the difference between the etching rates of the exposed portion and the unexposed portion of the heat-sensitive material layer 102. The heat-sensitive material layer 102 includes at least Sb and O. When the composition ratio of O is defined as x (atom %), x is 3 or more and 50 or less.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for producing a master disk for an optical disk used for reproducing information, and the like.

[0003] 2. Description of the Prior Art

[0004] Optical recording media onto which information is recorded and reproduced by irradiation with a light beam have been widely utilized, and in the future, attention will also be focused on the improvements in recording densities thereof.

[0005] Recently, a variety of optical disks capable of reproducing image / sound data and digital data with large capacities have been developed. For example, research and development has been undertaken so as to increase the storage capacity of an optical disk having a diameter of 12 cm up to a high density of 23.3 to 30 GB.

[0006] Optical disks are reproduced in large quantities by making master disks or stampers manufactured from master disks and then subjecting them to injection molding. Conventionally...

Examples

embodiment 1

[0047] (Embodiment 1)

[0048] In Embodiment 1, a low oxidation film was formed as a heat-sensitive material layer 102 on a substrate 101 such as an abraded glass substrate. After a direct current magnetron sputtering apparatus was equipped with a Sb target and after the glass substrate 101 was fixed on a substrate holder, the inside of the chamber was vacuum discharged using a cryopump up to a high vacuum of 1×10−4 Pa. While vacuum discharging, Ar gas was introduced into the chamber up to 0.10 Pa and then an O2 gas was introduced up to a total pressure of 0.11 Pa. Thereafter, while rotating the substrate 101, direct current was applied to the Sb target to form the film such that the film thickness of the Sb oxide became 80 nm.

[0049] In the present embodiment, by introducing an O2 gas during film formation, a low oxidation Sb film could be formed on the substrate 101. However, a material with a composition of a low oxidation Sb film may be used for the target material to perform sputt...

embodiment 2

[0058] (Embodiment 2)

[0059] In Embodiment 2, film formation, recording and development were performed in the same manner as that of Embodiment 1. In the present embodiment, when Sb is film-formed as a heat-sensitive material under an atmosphere of O2, a target of Te using as an additive was electrically discharged at the same time to form a low oxidation film of Sb and Te. The Te content was adjusted by altering the input power of Te during sputtering.

[0060] Addition of Te to a heat-sensitive material layer 102 that contains Sb as the main component enabled a reduction in surface roughness of unexposed portion 104 during development. This surface roughness of the unexposed portion 104 is thought to be attributable to low resistance to a development fluid of portions incapable of maintaining a stable amorphous state. In Embodiment 2, it is thought that by addition of Te, the solubility of which is smaller than the solubility of Sb2O3, the Te can be separated out on the film surface ...

embodiment 3

[0064] (Embodiment 3)

[0065] The present embodiment will be set forth referring to FIG. 3. In the same manner as that of Embodiment 1, a low oxidation Sb film as a heat-sensitive material layer 302 was formed on a substrate 301 comprising Si by means of the magnetron sputtering process (FIG. 3(a)). Thereafter, to prevent the occurrence of defects in unexposed portions from the developing treatment, the heat-sensitive material layer 302 was subjected to an annealing treatment (FIG. 3(b)). The annealing treatment here was performed by placing the substrate 301 on which the heat-sensitive material layer 302 was formed in a clean oven. By measuring the temperature of the heat-sensitive material layer 302 and using the same recording apparatus as in Embodiment 1, minute crystallized portions were formed in the heat-sensitive material layer 302 (FIG. 3(c)). Subsequently, the crystallized portions were removed by soaking the resultant material in a 2% aqueous tetramethylammonium hydroxide s...

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for producing a master disk for an optical disk used for reproducing information, and the like.

[0003] 2. Description of the Prior Art

[0004] Optical recording media onto which information is recorded and reproduced by irradiation with a light beam have been widely utilized, and in the future, attention will also be focused on the improvements in recording densities thereof.

[0005] Recently, a variety of optical disks capable of reproducing image / sound data and digital data with large capacities have been developed. For example, research and development has been undertaken so as to increase the storage capacity of an optical disk having a diameter of 12 cm up to a high density of 23.3 to 30 GB.

[0006] Optical disks are reproduced in large quantities by making master disks or stampers manufactured from master disks and then subjecting them to injection molding. Conventionally...

Examples

embodiment 1

[0047] (Embodiment 1)

[0048] In Embodiment 1, a low oxidation film was formed as a heat-sensitive material layer 102 on a substrate 101 such as an abraded glass substrate. After a direct current magnetron sputtering apparatus was equipped with a Sb target and after the glass substrate 101 was fixed on a substrate holder, the inside of the chamber was vacuum discharged using a cryopump up to a high vacuum of 1×10−4 Pa. While vacuum discharging, Ar gas was introduced into the chamber up to 0.10 Pa and then an O2 gas was introduced up to a total pressure of 0.11 Pa. Thereafter, while rotating the substrate 101, direct current was applied to the Sb target to form the film such that the film thickness of the Sb oxide became 80 nm.

[0049] In the present embodiment, by introducing an O2 gas during film formation, a low oxidation Sb film could be formed on the substrate 101. However, a material with a composition of a low oxidation Sb film may be used for the target material to perform sputt...

embodiment 2

[0058] (Embodiment 2)

[0059] In Embodiment 2, film formation, recording and development were performed in the same manner as that of Embodiment 1. In the present embodiment, when Sb is film-formed as a heat-sensitive material under an atmosphere of O2, a target of Te using as an additive was electrically discharged at the same time to form a low oxidation film of Sb and Te. The Te content was adjusted by altering the input power of Te during sputtering.

[0060] Addition of Te to a heat-sensitive material layer 102 that contains Sb as the main component enabled a reduction in surface roughness of unexposed portion 104 during development. This surface roughness of the unexposed portion 104 is thought to be attributable to low resistance to a development fluid of portions incapable of maintaining a stable amorphous state. In Embodiment 2, it is thought that by addition of Te, the solubility of which is smaller than the solubility of Sb2O3, the Te can be separated out on the film surface ...

embodiment 3

[0064] (Embodiment 3)

[0065] The present embodiment will be set forth referring to FIG. 3. In the same manner as that of Embodiment 1, a low oxidation Sb film as a heat-sensitive material layer 302 was formed on a substrate 301 comprising Si by means of the magnetron sputtering process (FIG. 3(a)). Thereafter, to prevent the occurrence of defects in unexposed portions from the developing treatment, the heat-sensitive material layer 302 was subjected to an annealing treatment (FIG. 3(b)). The annealing treatment here was performed by placing the substrate 301 on which the heat-sensitive material layer 302 was formed in a clean oven. By measuring the temperature of the heat-sensitive material layer 302 and using the same recording apparatus as in Embodiment 1, minute crystallized portions were formed in the heat-sensitive material layer 302 (FIG. 3(c)). Subsequently, the crystallized portions were removed by soaking the resultant material in a 2% aqueous tetramethylammonium hydroxide s...

Images