JPS6363153A - Production of optical recording medium - Google Patents

Abstract

PURPOSE:To improve weatherability, sensitivity and signal quality by providing a tellurium-selenium-nitrogen layer into a recording layer by using a material contg. tellurium and selenium as a target and executing sputtering in a gas contg. gaseous nitrogen monoxide, dinitrogen oxide or nitrogen dioxide. CONSTITUTION:The layer essentially consisting of tellurium, selenium and nitrogen is provided in the recording layer 21 by using the material contg. tellurium and selenium as the target and executing the sputtering in the gas contg. the gaseous nitrogen monoxide, dinitrogen oxide or nitrogen dioxide. The thickness of the tellurium-selenium-nitrogen layer is preferably in a 100-1,000Angstrom range in terms of recording and reproducing characteristics and the range of 2-50atom% is preferable for the content of the selenium in terms of the recording and reproducing characteristics and weatherability. The content of the nitrogen is preferably >=2-<20atom% in terms of the recording and reproducing characteristics and weatherability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing an optical recording medium on which information can be recorded and reproduced using laser light.

[Prior Art] Optical disk memories, which record and reproduce information on a medium using laser light, have excellent characteristics as large-capacity recording devices because of their high recording density.

Tantalum and lead were first used as optical recording medium materials (Science 154.15
50°19E)6)). Since then, various materials have been used, but chalcogen elements such as tellurium (Te) or their compounds are often used (Japanese Patent Publication No. 47-2
13897), and tellurium-selenium based alloys are particularly commonly used (Japanese Patent Publication No. 54-41902, Japanese Patent Publication No. 57-7919, Japanese Patent Publication No. 57-56058).

In recent years, in order to downsize recording devices, semiconductor lasers have been used as laser light sources. Semiconductor lasers have an oscillation wavelength of around 800 nm, and tellurium-selenium alloys are relatively well suited to this wavelength range, and can provide moderate reflectance and moderate absorption (physica status solidi). , 5tat.

sol, 7.189.1964)).

An optical recording medium using this tellurium-selenium alloy as an optical recording layer has a structure as shown in FIG. That is, a recording layer 21 made of a tellurium-selenium alloy is provided adjacent to the substrate 1. The recording laser beam is focused and irradiated onto the recording layer 21 through the substrate 1, and pits 22 are formed. The substrate 1 is made of synthetic resin such as polycarbonate, polyolefin, polymethylpentene, acrylic, or epoxy resin, or glass, and is usually guided so that pits are recorded concentrically or spirally at regular intervals with high accuracy. A groove is provided.

When light enters a groove with a width similar to the diameter of the laser beam, the light is diffracted, and as the beam center shifts from the groove, the spatial distribution of the intensity of the diffracted light changes.This is detected and the laser beam is directed to the center of the groove. The servo system is configured as follows. The width of the groove is usually 0.3 to 1.3 layer m, and the depth of the groove is set within the range of 1712 to 174 of the laser wavelength used. A servo system is similarly configured for condensing light. Information is read by irradiating a laser beam with a weaker power than during recording so as to pass over the pits, and detecting changes in reflectance caused by the presence or absence of pits.

[Problems to be Solved by the Invention 1] However, optical recording media using a tellurium-selenium alloy layer as a recording layer do not satisfy all of weather resistance, sensitivity, and signal quality. 4 The present invention was made to solve the above problems, and its purpose is to provide a method for manufacturing an optical recording medium that has good weather resistance, high sensitivity, good signal quality, and stability. .

[Means for Solving the Problems] The present invention provides an optical recording medium in which a recording layer for recording information is formed on a substrate, a portion of which is selectively removed by laser light. ! ! The manufacturing method is such that in the recording layer,
A material containing tellurium and selenium is targeted, and at least a layer containing tellurium, selenium, and nitrogen as main components is provided by sputtering in nitrogen monoxide gas, nitrogen dioxide gas, or a gas containing nitrogen dioxide gas. This is a method of manufacturing an optical recording medium.

The thickness of the layer whose main components are tellurium, selenium, and nitrogen (hereinafter abbreviated as tellurium-selenium-nitrogen layer) is 100 to 10.
A range of 0.00 is desirable from the viewpoint of recording/reproduction characteristics, and the selenium content ranges from 2% to 50% in terms of atomic percent.
The nitrogen content is preferably in the range of 2% or more and less than 20% in terms of atomic percent from the viewpoint of recording/reproducing characteristics and weather resistance. In addition, the composition ratio of elements in the tellurium-selenium-nitrogen layer is determined by the composition ratio of the target and nitrogen monoxide (No.
) gas dinitrogen oxide (N20) gas or nitrogen dioxide (
Of course, it depends on the partial pressure of NO2) gas, but also on the size of the sputtering equipment (surface area of the sputtering chamber, etc.), sputtering time, etc. Therefore, in order to obtain the desired recording film composition, it is necessary to It is desirable to set the N0 partial pressure etc. appropriately for each device.

The layer mainly composed of tellurium, selenium, and nitrogen contains lead, antimony, arsenic, sulfur, tin, germanium, thallium, phosphorus, cadmium, indium, gallium, zinc,
In this case, at least one element selected from the group consisting of aluminum, copper, silver, magnesium, tantalum, gold, palladium, and cobalt may be added.
In some cases, the shape of the pit can be improved. However, the amount added is preferably less than 20 percent in terms of atomic percent.

The sputtering gas may be only one of No gas, N20 gas, and NO2 gas, but from the viewpoint of stability of discharge and film formation, a mixed gas with an inert gas is preferable. Furthermore, other gases may be mixed.

At least one layer formed of an oxide, nitride, fluoride, carbide, sulfide or boride may be provided between the tellurium-selenium-nitrogen layer and the substrate. In this case, there is a greater margin for recording power fluctuations, and tracking and focusing servo may become more stable.

Further, as the substrate, commonly used materials such as synthetic resins such as polycarbonate, polyolefin, polymethylpentene, acrylic and epoxy resins, and glass are used.

[Example] Examples of the present invention will be described below.

Cocoon inner diameter 15, outer diameter 1 annealed at 100℃ for 2 hours
Tellurium (Te) and selenium (Se) were deposited on a 30#, 1.2 m thick polycarbonate resin disk substrate with a guide groove by magnetron sputtering a tellurium-selenium alloy target with a mixed gas of argon (Ar> and NO). and nitrogen (
Tellurium with a ratio of N> of 85:8:7 in atomic percent
A selenium-nitrogen layer was formed to a thickness of about 240 layers, and then stored in an environment at a temperature of 85° C. and a relative humidity of 90% for 12 hours to produce an optical recording medium. When the reflectance of this optical disc at a wavelength of 8,300 people was measured, it was approximately 24%.

Semiconductor laser light with a wavelength of 8,300 is incident through the substrate and focused on the recording layer to a diameter of about 1.6, and the linear velocity of the medium is 5 and 6.
Recording was performed under the conditions of 5 m/SeC, recording frequency of 3.778H2, recording pulse width of 70 nSeC, and recording power of 6.0 mW, and reproduction was performed at 0.7 mW. The carrier-to-noise ratio (C/N) with a bandwidth of 30 kHz was good at 48d8. After this optical disc was stored in a high temperature and high humidity environment of 70° C. and 80% for 60 hours, the above characteristics were examined, and no change was observed, confirming that the optical recording medium had excellent weather resistance.

[Effects of the Invention] As explained above, according to the method of the present invention, it is possible to manufacture a stable optical recording medium with good weather resistance, high sensitivity, and good signal quality.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing an example of an optical recording medium. 1... Board 21...Recording layer 22...Pit

Claims (1)

[Claims] (1) A method for manufacturing an optical recording medium comprising forming a recording layer on a substrate, a portion of which is selectively removed by a laser beam to record information, wherein the recording layer contains tellurium and selenium. An optical recording medium characterized in that at least a layer containing tellurium, selenium, and nitrogen as main components is provided by sputtering a substance as a target in a gas containing nitrogen monoxide gas, dinitrogen oxide gas, or nitrogen dioxide gas. manufacturing method.