JP2508188B2 - Optical recording medium manufacturing method - Google Patents

Description

The present invention relates to an optical recording medium manufacturing method, and more particularly to an optical recording medium manufacturing method for manufacturing an optical recording medium capable of recording and reproducing information by laser light. Regarding

[Conventional technology]

In the conventional optical recording medium manufacturing method, an optical disk memory in which information is recorded on a substrate by laser light and reproduced is generally excellent in a large capacity recording device because of its high recording density. As the material for this optical recording medium,
First tantalum and lead were used {Science (Scienc
e) 154 , 1550, 1966}. Since then, various materials have been used, but chalcogen elements such as tellurium or these compounds are often used (Japanese Patent Publication No. 47-26897), and tellurium-selenium alloys are often used ( JP-B-54-41902, JP-B-57-7919, JP-B-57
-56058).

An example of 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 tellurium-selenium alloy is provided adjacent to the substrate 1. The recording laser beam is condensed and irradiated on the recording layer 21 through the substrate 1 to form pits 22. As the substrate 1, synthetic resin such as polycarbonate, polyolefin, polymethylpentene, acryl, epoxy resin, or glass is used, and the pits are normally formed on the substrate 1 so that pits are concentrically or spirally accurately recorded at regular intervals. A guide groove is provided.

When light enters a groove with a width of about the laser beam diameter, the light is diffracted and the spatial distribution of the diffracted light intensity changes as the beam center shifts from the groove.Therefore, detect this and let the laser beam enter the center of the groove. Servo system is configured. The width of the groove is usually 0.3 to 1.3 μm, and the depth of the groove is set in the range of 1/20 to 1/4 of the laser wavelength used. A servo system is similarly configured for focusing.

Reading of information is performed by irradiating a laser beam having a lower power than at the time of recording so as to pass over the pits, thereby detecting a change in reflectance caused by the presence or absence of the pits.

In recent years, a semiconductor laser has been used as a laser light source in order to miniaturize a recording device. A semiconductor laser has an oscillation wavelength of around 8000Å, but a tellurium-cern alloy is relatively well suited to this wavelength band, and can obtain an appropriate reflectance and an appropriate absorptivity {Physica Status Solidide, 7 , 189,1964 (phys.stat.sol. 7, 189,1964) }.

The present inventors have found that among tellurium-selenium alloys, a recording film containing tellurium, selenium, lead, nitrogen, and oxygen as main components has good weather resistance, and a good quality recording / reproduction signal can be obtained. , Have already proposed.

In the conventional optical recording medium manufacturing method, a target consisting of tellurium, selenium, and lead is sputtered in a mixed gas of argon and nitrogen to form a film containing tellurium, selenium, lead, and nitrogen as main components. Then, the film was made to be a recording film containing crystalline tellurium, selenium, lead, nitrogen and oxygen as main components by storing the film in a high temperature and high humidity environment.

[Problems to be Solved by the Invention]

However, such a conventional optical recording medium manufacturing method as described above has a drawback in that the composition of the recording film changes when a target composed of three tellurium, selenium and lead is used for a long time.

The present inventor has investigated this reason and found that the composition ratio of lead with respect to tellurium and selenium in the target changes while the sputtering is performed many times, and the present invention has been completed. It is a thing.

[Means for solving the problem]

The optical recording medium manufacturing method of the present invention includes a sputtering chamber mounting step of setting a substrate, a tellurium selenium target, and a lead target in a sputtering chamber,
A mixed gas introduction step of introducing a mixed gas of argon and nitrogen into the sputtering chamber, a film forming step of forming a film on the substrate by performing sputtering in the sputtering chamber, and discharging the mixed gas from the sputtering chamber. A mixed gas discharging step, a high temperature and high humidity tank placing step in which the film-formed substrate is taken out of the sputtering chamber and placed in a high temperature and high humidity tank, and a high temperature and high humidity environment for making the high temperature and high humidity tank into a high temperature and high humidity environment And a recording film forming process of storing the formed substrate in the high temperature and high humidity tank and converting the formed film into a recording film.

That is, an optical recording medium manufacturing method of the present invention is a method of manufacturing an optical recording medium in which a part of a recording film is selectively removed by laser light to record information, and a substrate is placed in a sputtering chamber. Then, the first target containing tellurium and selenium as the main components and the second target containing lead as the main components are simultaneously sputtered in a mixed gas of argon and nitrogen to produce tellurium, selenium, lead and nitrogen. A film containing the main component is prepared and then stored in a high temperature and high humidity environment to form a recording film containing crystalline tellurium, selenium, lead, nitrogen and oxygen as the main components. To be done.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a manufacturing process drawing showing an embodiment of the present invention, and FIG. 2 is a partial sectional view showing an example of an optical recording medium prepared in the embodiment shown in FIG.

The optical recording medium manufacturing method shown in FIG. 1 includes a sputtering chamber mounting step S1, a mixed gas introducing step S2, a film forming step S3, a mixed gas discharging step S4, and a high temperature and high humidity tank mounting step S5. A high temperature and high humidity step S6 and a recording layer forming step S7 are included.

That is, the optical recording medium manufacturing method shown in FIG. 1 comprises a sputtering chamber mounting step S1 of mounting the substrate 1, the tellurium selenium target and a lead simple substance target in the sputtering chamber, and argon and nitrogen in the sputtering chamber. Mixed gas introduction step S2 of introducing a mixed gas, and film forming shape step S3 of forming a film on the substrate 1 by performing sputtering in the sputtering chamber.
A mixed gas discharging step S4 of discharging a mixed gas from the sputtering chamber; a high temperature and high humidity tank placing step S5 of taking out the film-formed substrate 1 from the sputtering chamber and placing it on a high temperature and high humidity tank; It includes a high temperature and high humidity step S6 for making a high temperature and high humidity tank into a high temperature and high humidity environment, and a recording layer forming step S7 in which the film-formed substrate is stored in the high temperature and high humidity tank to form the film as a recording layer. Composed of.

 Next, the embodiment shown in FIG. 1 will be described in detail.

Inner diameter 15mm, outer diameter 130mm, annealed at 100 ℃ for 2 hours,
On a substrate 1 of injection molded polycarbonate resin disk with a guide groove having a thickness of 1.2 mm, a target of tellurium selenium and a lead simple substance is placed in a sputtering chamber, and a mixed gas of argon and nitrogen is introduced into this sputtering chamber, and this atmosphere is introduced. Then, a tellurium selenium target and a lead simple substance target were simultaneously sputtered to form a film made of tellurium, selenium, lead and nitrogen with a thickness of about 240 Å.

Thereafter, the substrate 1 on which the film has been formed is stored for 12 hours in an environment of high temperature and high humidity at a temperature of 85 ° C. and a relative humidity of 90% to crystallize the film and oxidize the crystal grain boundaries, thereby recording layer 21. The optical recording medium shown in FIG. 2 was manufactured.

Analysis of this recording film 21 revealed that the atomic ratio of tellurium, selenium, lead, nitrogen, and oxygen was about 57: 16: 6: 1: 20.
Met.

When the reflectance of the land portion incident on the substrate 1 at a wavelength of 8300Å of this optical recording medium was measured, it was about 30%. A semiconductor laser beam with a wavelength of 8300Å is incident through the substrate and focused on the recording layer 21 to about 1.6 μmφ, and the medium linear velocity is 5.6
Pit 11 was recorded on the land part under the conditions of 5 m / sec, recording frequency 3.77 MHz, recording pulse width 70 nsec, recording power 5.4 mW, and 0.7
Played back at a constant power of mW. The carrier-to-noise ratio (C / N) with a bandwidth of 30 kHz was as good as 50 dB.

When a large number of optical recording media were prepared in the same manner by performing sputtering many times and evaluated, the composition ratio did not change, and the reproducibility of the recording / reproducing characteristics was good.

The thickness of the recording layer 21 is preferably in the range of 160Å to 400Å,
The content of selenium is preferably in the range of 9% to less than 35% in atomic%, the content of lead is preferably in the range of 5% to 15% in atomic%, and the content of nitrogen is 0.5% to 10% in atomic%. % Or less is desirable, and the oxygen content is about 5 in atomic%.
% To 25% is desirable.

〔The invention's effect〕

The optical recording medium manufacturing method of the present invention does not allow tellurium, selenium, and lead to coexist in a single target by simultaneously sputtering a tellurium selenium target and a lead simple substance target, and thus segregates lead in the target. The effect is that the optical recording medium can be manufactured without causing a change in the composition even after sputtering for a long time.

[Brief description of drawings]

FIG. 1 is a manufacturing process drawing showing an embodiment of the present invention, and FIG. 2 is a partial sectional view showing an example of an optical recording medium prepared in the embodiment shown in FIG. S1 ... Sputtering chamber placement process, S2 ... Mixed gas introduction process, S3 ... Film formation process, S4 ... Mixed gas discharge process, S5 ... High temperature / high humidity tank placement process, S6 ... High temperature / high humidity Process, S7 ... recording layer forming step, 1 ... substrate, 21 ... recording layer, 22 ... pit.

Claims (1)

(57) [Claims] 1. A sputtering chamber placing step of placing a substrate, a tellurium selenium target and a lead simple substance target in the sputtering chamber, and a mixed gas introducing step of introducing a mixed gas of argon and nitrogen into the sputtering chamber. A film forming step of forming a film on the substrate by performing sputtering in the sputtering chamber, a mixed gas discharging step of discharging a mixed gas from the sputtering chamber, and taking out the film-formed substrate from the sputtering chamber at a high temperature. A high-temperature high-humidity tank placing step of placing the high-temperature high-humidity tank in a wet tank, a high-temperature high-humidity step of making the high-temperature high-humidity tank a high-temperature high-humidity environment, and the substrate on which the film has been formed is stored in the high-temperature high-humidity tank, A recording layer forming step of forming a recording layer into a recording layer, the optical recording medium manufacturing method.