JPH06342535A - Optical recording medium and its production - Google Patents

Abstract

PURPOSE:To improve shape stability and to stably maintain C/N of the reproduced signals of the optical recording media at high level by applying inorg. dielectric films formed by a CVD method using the plasma which is generated by dielectric coupling of a high-frequency electric field and a magnetic field and helically propagate along the magnetic field to the optical recording media. CONSTITUTION:This process is provided with a charging chamber 11 for substrates 10, a deaerating chamber 12, film forming chambers 13, 14 for the inorg. dielectric films 42, 43, a film forming chamber 15 for recording films 14, a film forming chamber 16 for reflection films and a taking out chamber 16 for the substrates 10 formed with the recording films 41 and the inorg. dielectric films 42, 43. Openable and closable doors are disposed between the respective chambers. A substrate holder 18 for holding the substrates 10 is formed movably successively from the chamber 11 to the chamber 17. The substrates 10 are transported from the chamber 11 toward the chamber 17. The deaeration of the substrates 10, the formation of the inorg. dielectric films 42, the formation of the recording films 41, the formation of the inorg. dielectric films 43 and the formation of the reflection layers 44 are successively executed in the respective chambers. As a result, the optical recording medium having the laminated films of the films 41 to 44 on the substrates 10 are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium and a manufacturing method thereof, and more particularly to an optical recording medium having an inorganic dielectric film on a substrate and a manufacturing method thereof.

[0002]

2. Description of the Related Art Recently, a recording medium having a large recording capacity and capable of high-speed data transfer has been required as a computer memory or an image information memory. As an optical recording medium which records and reproduces using a laser beam as a recording medium which meets these demands, for example, a magneto-optical recording medium and a phase change recording medium have been actively developed.

That is, in a magneto-optical recording medium, when deflected laser light is applied to the surface of a recording layer containing a magnetic substance, the direction of rotation of the deflecting surface of the reflected laser light differs depending on the direction of its magnetization ( (Kerr effect) is used to record and reproduce information. On the other hand, a phase-change recording medium is, for example, between an amorphous state and a crystalline state generated when a recording layer containing Te is irradiated with laser light. In this method, information is recorded and reproduced by utilizing the reversible phase transition in the above and different optical characteristics shown in each state.

By the way, in order to obtain a reproduced signal having a larger C / N ratio, these optical recording media are provided with an inorganic dielectric film between the recording film and the substrate, for example, and the reproduced signal is produced by using an optical interference effect. Amplification (enhancement effect), and further, as shown in FIG. 4A, the recording film 41 is sandwiched between the inorganic dielectric films 42 and 43 to function as a protective film for the recording film 41 together with amplification of reproduction light. It is known that the structure is adopted, and that the reflective layer 44 is added on the inorganic dielectric layer 43 as shown in FIG. 4B in order to further enhance the interference effect.

And as such an inorganic dielectric layer,
Conventionally, for example, Si ₃ N ₄ , SiC, SiO, SiO
₂ , amorphous Si (a-Si), AlN, Al ₂ O
Thin films of ₃ , TiO ₂ , Ta ₂ O ₅ , ZnS, etc. are used.

By the way, the performance of the magneto-optical recording medium or the phase change type optical recording medium using such an inorganic dielectric, such as the C / N ratio of the reproduced signal and the stability of the recording film with time, is as described above. Not only that, but it also depends greatly on the characteristics of the dielectric film. Therefore, at the research institutes in Japan and abroad, the enhancement effect of the reproduction signal is great for the high performance of the optical recording medium, and the protection performance of the recording layer is excellent. Active research and development have been conducted on dielectric materials and manufacturing methods. For example, as disclosed in Japanese Examined Patent Publication No. 15929/1990, AlN or SiN is used as an Al target or a Si target as N ₂
It is produced by reactive sputtering in a gas atmosphere, or is disclosed in JP-A-3-66043 or JP-A-3-66043.
Attempts have been made to form an inorganic dielectric film for an optical recording medium by the ECR plasma CVD method as described in JP-A-69033 and JP-A-4-30343.

In particular, the plasma CVD method has been attracting attention in recent years as an elemental technology for obtaining a high quality optical recording medium at a low cost because it can improve the film forming rate as compared with the sputtering method. It is a thing.

However, when this plasma CVD film forming method is intended to achieve a high level of protection performance of the recording layer,
It is inevitable that the inorganic dielectric film contains strong stress,
This tendency was more remarkable than when the film was formed by increasing the plasma density in order to increase the film forming speed. Since such an inorganic dielectric film causes a large warp in the optical recording medium, it cannot be applied to the optical recording medium. When an inorganic dielectric film for an optical recording medium is produced by a conventional plasma CVD method, the dielectric The recording layer protection performance of the body film is actually determined in consideration of the internal stress of the inorganic dielectric film.

However, under the situation where a higher quality optical recording medium is demanded, even when an inorganic dielectric film for an optical recording medium is produced by using the plasma CVD method, the content of the inorganic dielectric film in the inorganic dielectric film is increased. It has been required to further improve the protective performance of the recording layer while suppressing the increase in internal stress as much as possible.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and maintains the C / N ratio of a reproduced signal at a high level for a long time while suppressing deformation such as warpage and bending. It is an object of the present invention to provide a method for producing an optical recording medium capable of further improving stability with time.

Further, according to the present invention, there is little deformation such as warping or bending,
Another object of the present invention is to provide a high quality optical recording medium having a high C / N ratio of reproduced signals and excellent stability of the recording layer over time.

[0012]

The inventors of the present invention have conducted various studies on the above-mentioned object, and as a result, have made a helicon wave plasma CVD.
Method, that is, by the inductive coupling of high-frequency electric and magnetic fields,
C using a plasma propagating helically along a magnetic field
When the inorganic dielectric film formed by the VD method is applied to an optical recording medium, the shape stability is excellent as compared with the conventional optical recording medium using the inorganic dielectric film formed by the ECR plasma CVD method, and The present invention has been accomplished by discovering that the C / N ratio of a reproduction signal of an optical recording medium can be maintained more stably at a high level, and the present invention has been achieved. In a method of manufacturing an optical recording medium having a laminated film of inorganic dielectric films, the inorganic dielectric film is formed by using a helicon wave plasma CVD method.

The optical recording medium of the present invention is an optical recording medium having a laminated film of a recording film and an inorganic dielectric film on a substrate, wherein the inorganic dielectric film is formed by a helicon wave plasma CVD method. It is characterized by.

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

FIG. 1 is a continuous film-forming apparatus for an in-line inorganic dielectric film and a recording film, which is applied to an embodiment of a method of manufacturing an optical recording medium as shown in FIG. 4B according to the present invention. 11 is a schematic plan view of the substrate, 11 is a charging chamber for the substrate 10, 12 is a deaeration chamber, 13 and 15 are chambers for forming the inorganic dielectric films 42 and 43, and 15 is a recording film 41, for example, a magneto-optical recording film. Membrane chamber,
16 is a film forming chamber for the reflective film, and 17 is a chamber for taking out the substrate 10 on which the recording film 41 and the inorganic dielectric films 42, 43 are formed. An openable and closable door (not shown) is provided between the chambers, and a substrate holder 18 for supporting the substrate 10 is provided from the substrate loading chamber 11 to the substrate unloading chamber 17
It is formed so that it can be sequentially moved up to. The substrate 10 for optical recording medium is conveyed from the substrate loading chamber 11 to the substrate unloading chamber 17, and in each chamber, the substrate 10 is degassed, the inorganic dielectric film 42 is formed, the recording film 41 is formed, and the inorganic film is formed. By sequentially forming the dielectric film 43 and the reflective layer 44, an optical recording medium including a laminated film of the recording film 41, the inorganic dielectric films 42 and 43, and the reflective layer 44 is formed on the substrate. is there.

In this embodiment, the helicon wave plasma CVD film forming apparatus is arranged in the film forming chambers 13 and 15 for the inorganic dielectric film.

FIG. 2 is a direction orthogonal to the substrate transport direction of the helicon wave CVD film-forming apparatus arranged in the film-forming chambers 13 and 15 in which the inorganic dielectric films 42 and 43 of the film-forming apparatus of FIG. 1 are formed. 2 is a schematic cross-sectional view of FIG.
Is a cylindrical plasma generating vessel extending along this axis, 22 is an antenna for forming a high-frequency electric field inside the plasma generating vessel, and 23 is the axis inside the plasma generating vessel. A coil for forming a magnetic field in the direction along X, and 24 is a process container connected to the plasma generating container in the axial direction. Further, 25 is the plasma generation container 2
1 is a means for introducing gas into the chamber 1, 26 is a means for introducing gas into the process container 24, and 27 is a substrate 1 for the optical disk.
The substrate holder 18 holding 0 is held in the process container so that the film forming surface of the substrate 10 is orthogonal to the axis X, and the substrate holder is rotated about the axis X during the film forming process. Substrate holding means.

The matching box 2 is provided on the antenna 22.
An RF power source 29 is connected via 8 and a high frequency electric field can be formed in the plasma generating container 21.

FIG. 3 is a helicon wave C which can be used in the inorganic dielectric film forming chambers 13 and 15 of the in-line type film forming apparatus of FIG.
FIG. 4 is a schematic cross-sectional view showing another embodiment of the VD film forming apparatus, in which the process container 24 of the device of FIG.
Helicon wave plasma C of FIG. 2 at one point of No. 5
It is different from the VD device.

Then, for example, when a SiNx film is formed using the helicon wave CVD film forming apparatus configured as shown in FIG. 2, after the plasma generating container 21 and the process container 24 are evacuated by the vacuum pump 30, Plasma generation container 2
Introducing N ₂ gas as a reaction gas into the chamber 1 through the introducing pipe 25 and SiH ₄ as a source gas into the process chamber 24, a high frequency electric field is generated in the plasma generating chamber by using the antenna 22. Also, by using the coil 23 to form a magnetic field in the plasma generating container in the direction along the axis X, it is possible to generate plasma mainly from N ₂ gas in the plasma generating container 21 and to generate the magnetic field in the plasma. Can be propagated in a helical shape along the path to the process container, and the SiH ₄ gas is ionized by receiving the energy of the plasma in the process container, and as a result, a SiNx film is formed on the substrate. Is something that can be done.

Then, the helicon wave C shown in FIG. 2 or FIG.
The coil 23 used in the VD film forming apparatus is preferably arranged in the plasma generation container 21 so that a magnetic field is generated in a direction along the axis X direction in order to generate helicon wave plasma in the plasma generation container 21. . Further, as the strength (G) of the applied magnetic field, the plasma density generated in the plasma generation container 21 is at least 1 × 10 5 in cooperation with the RF electric field applied to the plasma generation container 21 by the antenna 22. It is preferable to set ¹¹ pieces / cm ³ or more, preferably 1 × 10 ¹² pieces / cm ³ or more. Particularly, for example, a frequency of about 10 to 30 MHz R
When an F electric field is formed in the plasma generation container 21 by the antenna 22, "G" is greater than 0 gauss and 500 gausses or less, particularly more than 0 gauss and 200 gausses or less at the central portion of the plasma generation container 21, and The number of turns of the coil and //
Alternatively, adjusting the current flowing through the coil is preferable in order to form an inorganic dielectric film for an optical recording medium having a high recording layer protection performance without increasing stress. In the structure of the antenna 22 which is a means for generating an RF electric field in the plasma generating container in this embodiment, for example, an RF current surrounds the plasma generating container 21 as disclosed in US Pat. No. 4,990,229. Draw two circular loops separated from each other and RF of one loop
So that the current passes in the clockwise direction and the RF current in the other loop passes in the counterclockwise direction, for example in FIG.
The structures shown in (b) and (c) are preferable for reducing the stress of the inorganic dielectric film.

In particular, when the antenna having the shape shown in FIG. 5A is used, a high-quality inorganic dielectric film can be formed at a high speed, and a high-quality optical recording medium can be manufactured at low cost. It is preferable. Although the reason why the antenna having such a shape has the above-mentioned effects is not clear, the influence of the interaction between the magnetic field generated when the RF current is applied to the antenna and the magnetic field applied by the coil 23 is suppressed to be relatively small. It is thought that it is possible to do.

Furthermore, controlling the distance (l) between the two loops surrounding the plasma generating vessel 21 of the antenna improves the quality of the inorganic dielectric film, which in turn has a favorable effect on the quality of the optical recording medium. Is preferred. The interval (l) varies depending on the film-forming material, the frequency of the applied electric field, the size of the plasma generation container 21 and the strength of the magnetic field applied by the coil 23, and is not generally determined. The inner diameter of 21 is 80 to 300 mm, the frequency of the RF electric field is 10 to 30 MHz, and the magnetic field strength at the center of the plasma generation container 21 is 0 Gauss <G ≦ 500 Gauss.
When forming an i-type inorganic dielectric film, the loop interval (l)
Of 100 to 500 mm, especially 100 to 250 mm, which is equivalent to a film formed by sputtering and is preferably 1.7 to 3.7, particularly about 1.9 to 2.7, in order to achieve the enhancement effect. The stress condition required for the inorganic dielectric film is ± 30 kg / mm ² or less, especially ± 25 kg / mm ² or less (where “+” is tensile stress, “ It is possible to prepare an inorganic dielectric film that satisfies the compressive stress (-) and has a very excellent recording layer protection performance and that provides a high quality optical recording medium.

In the present invention, the position of the substrate arranged in the process container or plasma generating container will be described.
For example, when the helicon wave plasma CVD apparatus as shown in FIG. 2 is used, FIG. 7A and its sectional view taken along line BB in FIG.
As shown in (b), when the diameter of the window of the connecting portion between the plasma generation container 21 and the process container 24 is d, the substrate is a region 71 within a circle with a radius d / 0.5 centered on the axis X, particularly ,
It is preferably arranged so as to lie in a region 72 within a circle of radius d / 1.6.

That is, in this case, it is possible to suppress the occurrence of unevenness in the thickness of the inorganic dielectric film on the same substrate, and in the case of simultaneously forming films on a plurality of substrates, it is possible to form the inorganic dielectric films between the same lot. It is possible to suppress variation in quality of the optical recording medium due to unevenness in film thickness.

Incidentally, the helicon wave plasma CV of the present invention
The gas used for forming the inorganic dielectric film for an optical recording medium by the D method is, for example, an inorganic dielectric film such as a-
When forming a Si-based semiconductor film such as Si or SiC, S
Examples of the source gas containing i include SiH ₄ and SiH
Inorganic silanes such as ₆ , tetraethylsilane (TE
S), tetramethylsilane (TMS), organic silanes such as dimethylsilane (DMS), SiF ₄ , Si ₂ F
₆ , SiHF ₃ , SiH ₂ F ₂ , SiCl ₄ , Si ₂ C
l ₆ , SiHCl ₃ , SiH ₂ Cl ₂ , SiH ₃ Cl,
It is preferable to use at least one of halosilanes such as SiCl ₂ F ₂ which is in a gas state at room temperature and normal pressure, or which is easily gasified, and SiNx, SiO, SiO ₂ etc. as the inorganic dielectric film. In the case of forming a Si compound-based film of, for example, as a raw material gas containing Si atoms, inorganic silanes such as SiH ₄ and SiH ₆ , tetraethoxysilane (TEOS), tetramethoxysilane (T
MOS), octamethylcyclotetrasilane (OMCT
S) and other organic silanes, SiF ₄ , Si ₂ F ₆ , Si
HF ₃ , SiH ₂ F ₂ , SiCl ₄ , Si ₂ Cl ₆ , S
iHCl ₃ , SiH ₂ Cl ₂ , SiH ₃ Cl, SiCl
₂ F _2, such as halosilanes, which are in a gas state at room temperature and normal pressure, or which are easily gasified, and reaction gases such as NH ₃ , N ₂ N ₄ , hexamethyldisilazane (HMDS), and O. ₂ , O ₃ , H ₂ O, NO, N ₂ O,
It is preferable to appropriately select and use NO ₂ or the like.

As the inorganic dielectric film, AlN, Al ₂ O
_When forming a metal compound thin film of ₃ , ₃ , TiO ₂ or Ta ₂ O ₅ , trimethylaluminum (TMAl), trierylaluminum (TEAl), triisobutylaluminum (TIBA) is used as a source gas containing metal atoms.
l), dimethyl aluminum hydride (DMAl
H), organic metals such as AlCl ₃ , TiCl ₃ , Ta
O as a reaction gas with metal halides such as Cl _5
2 , O ₃ , H ₂ O, NO, N ₂ O, NO ₂ , N ₂ , NH
It is preferable to appropriately select and use ₃ , ₃ , N ₂ H ₄ , hexamethyldisilazane (HMDS) and the like.

When two kinds of raw material gas and reaction gas are used for forming the inorganic dielectric film as described above, a two-chamber structure consisting of the plasma generating container 21 and the process container 24 as shown in FIG. It is preferable to use the apparatus and to introduce the reaction gas and the raw material gas into different containers, and in particular, the reaction gas is introduced from the gas introducing means 25 into the plasma generation vessel 21, and the raw material gas is processed from the gas introducing means 26. Container 2
In the case of being introduced into No. 4, since the plasma density in the vicinity of the substrate 10 can be further increased, it is possible to extremely efficiently manufacture the inorganic dielectric film which gives a high quality optical recording medium.

Further, the process container 24 of the apparatus shown in FIG.
6, a permanent magnet 61 is arranged around the wall of the same so that the same pole extends in the direction of the axis X and the N pole and the S pole alternate in the circumferential direction of the process container 24. In this case, while maintaining excellent recording layer protection performance and low internal stress, which are preferable characteristics as an inorganic dielectric film for an optical recording medium, adhesion of the inorganic dielectric film to the inner wall of the process container 24 is suppressed and the film forming process is high. This is preferable because it can improve efficiency.

The strength of the permanent magnet used here is preferably 200 to 1000 gausses, particularly 700 to 900 gausses, and more preferably 800 gausses.

Next, the conditions for forming the inorganic dielectric film for an optical recording medium using the helicon wave plasma CVD apparatus described above will be described in more detail. The power supplied when the RF current is supplied from the RF power supply to the antenna is 0. .5-5 kW,
Particularly, it is preferable to set 1 to 3 kW, and the total pressure of the raw material gas or the reaction gas or the mixed gas thereof in the plasma generation container and / or the process container is 0.1 to 2
It is preferable to form a film in Pa, particularly in the range of 0.5 to 1.0 Pa.

Next, in the method for producing an optical recording medium of the present invention, the constitution other than the step of forming the inorganic dielectric film according to the features of the present invention by the helicon wave plasma CVD method is not limited. For example, the order of the step of forming the inorganic dielectric film and the step of forming the optical recording film is not limited to the order of the inline process of FIG. 1, and the steps are sequentially performed according to the configuration of the desired optical recording medium. Should be done.

For the step of forming the recording film, a known film forming method suitable for the characteristics of the material used for the recording film may be used, and specifically, for example, vapor deposition, sputtering, wet coating or the like can be used.

Further, in the present invention, as the optical recording film,
An optical recording film capable of recording / reproducing information by irradiation with a light beam can be used without particular limitation, but an amorphous magnetic film containing a rare earth element and / or a transition metal, for example, Tb-Fe-Co. , Gd-Fe-Co, Tb-Fe
-Co-Cr or Gd-Fe-Co-Cr or other amorphous magnetic film containing a rare earth and / or transition metal, or a magneto-optical recording film having a laminated film thereof or a recording film containing chalcogenide element such as Te. Is highly corrosive, the inorganic dielectric film is required to have particularly excellent recording layer protection performance, and therefore the effect of the method for producing an optical recording medium of the present invention can be more effectively exerted. Is preferable.

In the optical recording medium according to the present invention, the thickness of the inorganic dielectric film is set according to the material and structure of the recording layer and the characteristics of the inorganic dielectric film. In the structure in which the two layers of the inorganic dielectric films are arranged so as to sandwich the magneto-optical recording film as described above, the substrate and the substrate are used to protect the recording layer and enhance the Kerr rotation angle during signal reproduction. About 100 to 1500Å for the inorganic dielectric film of the magneto-optical recording film, and about 100 for the inorganic dielectric film on the magneto-optical recording film.
It is preferably about 1000 Å.

If desired, a protective layer may be provided on the recording layer of the optical recording medium, the inorganic dielectric film, or the reflective layer obtained by the method for producing an optical recording medium of the present invention. In this case, for example, the protective layer is formed by applying a photocurable resin on the recording layer so as to have a predetermined thickness (for example, 10 to 30 μm) and then irradiating it with light to cure it. Can be formed by adhering a resin sheet (for example, a polycarbonate resin sheet or a polyester resin sheet) formed on the recording layer, the inorganic dielectric film, or the reflective layer with an adhesive or a pressure-sensitive adhesive. It is particularly preferable in the present invention to use a resin sheet formed into a protective layer as the protective layer because it can prevent the internal stress of the protective layer from deforming the optical recording medium.

As the substrate of the optical recording medium according to the present invention, a substrate generally used as a substrate for optical recording medium can be used. For example, glass, bisphenol-based polycarbonate resin or other modified polycarbonate resin, acrylic resin, A substrate containing an amorphous polyolefin resin can be used.

[0038]

The present invention will be described in more detail with reference to the following examples.

(Example 1) Outer diameter 130 mmφ, inner diameter 15
mmφ, thickness 1.2 mm, width 0.6 μm on one surface,
A side of a disk substrate made of a donut-shaped polycarbonate resin (trade name: Iupilon H4000; manufactured by Mitsubishi Gas Chemical Co., Inc.) in which a spiral pre-groove having a pitch of 1.6 μm and a depth of 800 Å is formed, on which a track groove is formed. 950Å thick SiN as a first dielectric film on the surface of
xd film, 1.00 Å thick Gd-Fe-Co as recording layer
A laminated film of an amorphous magnetic layer and a Tb-Fe-Co amorphous magnetic layer having a thickness of 200Å, a SiNx film having a thickness of 300Å as a second dielectric layer, and an Al film having a thickness of 600Å as a reflective layer are sequentially laminated. The formed magneto-optical disk was formed into a film by the following method.

That is, first, the in-line type film forming apparatus shown in FIG. 1 was prepared. In the film forming apparatus, a helicon wave CVD film forming apparatus was arranged in the film forming chambers 13 and 15 for the first and second SiNx films as shown in FIG.

In the helicon wave CVD film forming apparatus used here, the plasma generating vessel 21 has an outer diameter of 115 mm and an inner diameter of 10 mm.
0 mm, 150 mm long cylindrical shape, and the container 21
400mm outside, 380mm inside, length 4
The 50 mm cylindrical process vessels 24 are connected so that their central axes coincide with each other, and the diameter of the window of the connecting portion is 100 m.
m. The antenna 22 has the structure shown in FIG. The radius of the loop portion of this antenna was 65 mm, and the distance 1 between the loops was 150 mm. Further, a coil 23 for applying a magnetic field in the plasma generation container 21.
Is 100 near the central axis of the plasma generation vessel 21.
The configuration is such that a Gaussian magnetic field can be generated. Further, the disk substrate 10 was arranged so as to be always located in a circular region having a radius of 62 mm with the center axis of the process container 24 on the substrate holding means 27 as the center throughout the film forming process.

Next, the substrate holder 17 having one disk substrate 10 mounted therein is placed in the substrate loading chamber 11 of the in-line type film deposition apparatus having the SiN film deposition chamber having the above-described structure, and then the degassing chamber 12 is loaded. After transferring the substrate and degassing, first
The substrate is transferred to the SiNx film forming chamber 13 of the
An x film was formed.

As the SiNx film forming conditions, the vacuum pump 3 is used inside the plasma generation container 21 and the process container 24.
After evacuating to 10 ^-5 Pa using 0, N ₂ gas was introduced from the gas introducing means 25 into the plasma generating container at 203 SC.
It is introduced at a flow rate of CM, and SiH _{4 is} supplied from the gas introduction means 26.
Gas was introduced into the process container at a flow rate of 306 SCCM, and the pressures in the plasma generation container 21 and the process container 24 were adjusted to 0.7 Pa.

Next, the frequency of 13.
An RF current of 56 MHz and a power of 2.8 kw was applied, and a current of 5 A was applied to the coil to form a magnetic field of 100 Gauss in the plasma generation container to form a SiNx film. As a result, the first SiNx film with a thickness of 950Å is about 8
The film formation is completed in seconds, and the deposition rate of the SiNx film is about 7,000.
It was Å / min. The substrate temperature immediately after film formation is about 50 ° C.
Met.

After the formation of the first SiNx film is completed, the substrate is transferred to the recording layer film forming chamber, and the Gd-Fe-Co film and the Tb-F film are formed.
The e-Co film was formed by the RF sputtering method.

As the sputtering target, a GdFeCo alloy target having a diameter of 150 mm and a thickness of 6 mm or a TbFeCo alloy target having the same size was used, and the conditions for RF sputtering were to evacuate the inside of the chamber to 1 × 10 ⁻⁵ Pa. Sputtering was performed with Ar gas pressure of 0.1 Pa and RF power of 5.6 w / cm ² .

After the recording layer was formed, the substrate was transferred to the second SiNx film forming chamber 15 and the SiNx film was formed under the same conditions as the first SiNx film forming conditions. Therefore, the film formation time of the second SiNx film was 2 to 3 seconds.

Next, this substrate was transported to a film forming chamber for a reflection film, and an Al reflection film was formed by RF sputtering. An Al target having a diameter of 150 cm and a thickness of 6 mm was used as a sputtering target, and the conditions of RF sputtering were as follows: the chamber interior was evacuated to 1 × 10 ⁻⁵ Pa, the Ar gas pressure was 0.2 to 0.4 Pa, and the RF power was RF power. Sputtering was performed at 5 to 7 w / cm ² .

Next, the substrate was taken out from the in-line type film forming apparatus, and a polystyrene-polybutadiene block copolymer (trade name: Califlex, TR11) was formed on the Al reflection film.
07; Shell Kagaku Co., Ltd.), 100 parts by weight of modified wood rosin, 50 parts by weight of modified wood, and 1 part by weight of stabilizer are applied to form a rubber-based adhesive having a thickness of 2 μm, and then the thickness of the adhesive is increased on the adhesive layer. A film obtained by curing a urethane acrylate-based ultraviolet curable resin having a thickness of 6 μm was laminated to prepare a magneto-optical disk.

According to this method, a total of 10 magneto-optical disks were manufactured, and the C / N ratio and defect occurrence rate (B, E, R) of the magneto-optical disks thus obtained were set to an initial value and 80.
The value after standing for 1500 hours under conditions of ° C and 85% RH was measured and evaluated.

The C / N ratio and BER are magneto-optical disk recording / reproducing inspection equipment (product name, LN
52A; manufactured by Shiba Soku Co., Ltd.) to record information and reproduce the information for measurement.

However, the recording and reproducing conditions were as follows.

Linear velocity: 9.04 m / sec Recording frequency: 6 MHz Recording power: 10 mW Reproducing power: 1 mW Recording / reproducing light wavelength: 830 nm Moreover, the tilt angle measuring device (product name: It was measured using LM-100; manufactured by Ono Sokki Co., Ltd.). C / N ratio, B,
The data of E, R, and tilt angle were the average values of the values obtained from 10 discs.

The above results are shown in Table 1. In Table 1, the C / N ratio was evaluated as A when the change before and after the durability was 3 dB or more, B when it was 3 to 8 dB, and C when it exceeded 8 dB.

B. E. R. For A, if the value after durability has the same order as the initial value, the order is 1
The case where the digit decreased was evaluated as B, and the case where the order decreased by two digits or more was evaluated as C.

Further, the tilt angle was evaluated as A when it was within 5 mrad and as B when it exceeded 5 mrad.

Further, the stress and refractive index of the first SiNx film formed by the helicon wave plasma CVD method described above were measured according to the following method.

That is, a SiNx film was formed on a glass disk having a diameter of 30 mm and a thickness of 1.0 mm for stress measurement under the same film forming conditions as described above, and the deformation of this substrate was measured using an interferometer. Detected as the number of Newton rings. Here, when the number of Newton rings is m, the radius of curvature γ of the substrate is obtained by the following equation.

Γ = a ² / mλ ... a: Radius of substrate λ: Wavelength of light source used by interferometer Here, when the value of γ is substituted into the following equation, the stress σ of the first SiNx film is obtained.

[0060] ^{σ = Eb 2/6 (1} -ν) γd ... E: Young's modulus of the substrate [nu: Poisson's ratio of the substrate gamma: curvature of substrate radius d: thickness of SiNx film b: thickness of the substrate The first 1SiNx The refractive index of the film was calculated from the reflectance of the spectral characteristics of the sample formed on the glass substrate, and
The reflectance was measured at arbitrary 10 points on one sample, and the average value of the refractive indexes calculated therefrom was used as the refractive index of the sample. As for the stress and refractive index data, the minimum and maximum values of the data obtained from 10 samples prepared under the same conditions are shown in Table-1.

Further, the helicon wave plasma CVD described above is used.
In order to measure the thickness unevenness of the first SiNx film formed by the method, ten glass disks having a diameter of 130 mm and a thickness of 1.2 mm are prepared, and the above-mentioned helicon wave plasma CV is provided on the glass disks.
A 2000 Å-thick SiNx film was formed in exactly the same manner as in the D method, and in the area (corresponding to the recording area of the magneto-optical disk) surrounded by a circle with a radius of 30 mm and a circle with a radius of 60 mm on this disk. The film thickness of the SiNx film was measured at eight arbitrary locations. And when the film thickness at all measurement points on each disk is within ± 2.5% of the standard thickness, A
A, A when there is a substrate exceeding ± 2.5% and within ± 3%, A when there is a disk exceeding ± 3% and within ± 5%, B,
The case where there was a substrate exceeding ± 5% was evaluated as C.

Furthermore, a diameter of 130 mm and a thickness of 1.2 are newly added.
mm polycarbonate resin (trade name: Iupilon H4
000; a disk substrate manufactured by Mitsubishi Gas Chemical Co., Inc.) was prepared, and a 950 Å-thick SiNx film was formed by a helicon wave plasma method by the same procedure as described above. The measurement was performed by bringing a thermocouple into contact with the back surface. The above results are shown in Table-1.

Comparative Example 1 First SiN used in Example 1
The film forming devices 13 and 15 for the x film and the second SiNx film are shown in FIG.
As shown in FIG. 7, except that the electron beam cycloton resonance (ECR) plasma CVD film forming apparatus is equipped with a means 81 for introducing microwaves into the chamber and a coil 83 for generating electron cycloton resonance in the chamber. A magneto-optical disk was prepared in the same manner as in Example 1.

In this comparative example, the conditions for forming the SiNx film are as follows: the internal stress of the SiNx film is in the range of the stress allowed in the inorganic dielectric film for a magneto-optical disk (0 to -30 kg /
mm ² ), specifically, a frequency of 2.4
A microwave of 5 GHz is introduced into the plasma generation container 82 from the waveguide 81, and the coil 8 arranged outside the container.
The magnetic field (8
75 Gauss) was generated in the container. Also, the microwave power is 500 W and the gas flow rate is SiH ₄ .
0 SCCM, N ₂ is 30 SCCM, and the gas pressure in the plasma generation container 82 and the process container 84 is 1.0 P
Adjusted to a. The plasma generation container 82, the process container 84, and the substrate arranging method were the same as in the first embodiment. The internal stress of the SiNx film thus prepared is −
It was 30 kg / mm ² or less.

The magneto-optical disk thus prepared was evaluated in the same manner as in Example 1. As a result, as shown in Table-1, when stored under high temperature and high humidity conditions, the C / N ratio was significantly reduced and the B. E. A significant increase in R was observed.

Comparative Example 2 In order to obtain a dense and highly protective SiNx film, the gas pressure was set to 0.2 Pa under the film forming conditions of Comparative Example 1 to improve the plasma density to form a film. A magneto-optical disk was prepared in the same manner as Comparative Example 1 except that the operation was carried out.
It evaluated similarly to.

The stress of the SiNx film formed under the conditions of this comparative example was also measured in the same manner as in Example 1. As a result, as shown in Table-1, the C / N ratio B. E. R shows an excellent value even after the durability test, but SiN
Since the internal stress of the x film was high, the tilt angle after endurance showed a value exceeding the standard value of 5 mrad.

[0068]

[Table 1]

Example 2 The same as Example 1 except that a recording film made of a TbFeCo film having a thickness of 30 nm was formed by a magnetron sputtering method instead of the recording film made of the laminated film of the GdFeCo film and the TbFeCo film of Example 1. Then, a magneto-optical disk was created.

This magneto-optical disk had the same characteristics as in Example 1.

(Example 3) In Example 1, the first inorganic dielectric film and the second inorganic dielectric film were replaced by S instead of SiNx.
A magneto-optical disk was prepared in the same manner as in Example 1 except for using iC, and evaluated in the same manner as in Example 1. Note that Si
The conditions for forming the C film are as follows.

[0072]

[Table 2]

Further, the internal stress, the refractive index, the substrate temperature and the film thickness unevenness of the SiC film formed under these conditions were evaluated in the same manner as in Example 1. The results are shown in Table-2.

(Comparative Example 3) First SiC used in Example 3
A magneto-optical disk was prepared in the same manner as in Example 3 except that the film and second SiC film forming devices 13 and 15 were replaced by an electron beam cyclotron resonance (ECR) plasma CVD film forming device as shown in FIG.

In this comparative example, the conditions for forming the SiC film are such that the internal stress of the SiC film is in the range of stress (0 to -30 kg / mm) that is allowed in the inorganic dielectric film for magneto-optical disk.
² ) so that the frequency is 2.45G
The microwave of 8 Hz is guided from the waveguide 81 to the plasma generation container 8
The magnetic field (875) which satisfies the electron cyclotron resonance condition is introduced by the coil 82 which is introduced into
Gauss) was generated in the container.

The microwave power is 500 W,
The gas flow rate was adjusted to 10 SCCM for SiH ₄ and 15 SCCM for C ₂ H ₂ , and the gas pressure in the plasma generation container 82 and the process container 83 was adjusted to 1.5 Pa. The plasma generation container 82, the process container 83, and the substrate were arranged in the same manner as in the first embodiment. The internal stress of the SiC film thus formed was −30 kg / mm ² or less.

The magneto-optical disk thus prepared was evaluated in the same manner as in Example 1. As a result, as shown in Table 2, the C / N ratio was decreased and the B. E. An increase in R was recognized.

(Comparative Example 4) In order to obtain a dense and highly protective SiC film, the gas pressure was set to 0.4 Pa under the film forming conditions of Comparative Example 3 to improve the plasma density to form a film. A magneto-optical disk was prepared in the same manner as in Comparative Example 1 except that the evaluation was carried out, and this magneto-optical disk was evaluated in the same manner as in Example 1.

The stress of the SiC film formed under the conditions of this comparative example was also measured in the same manner as in Example 1. As a result, as shown in Table-2, C / N ratio, D. E. Regarding R, although it shows an excellent value even after the durability test, SiC
Since the internal stress of the film was high, the tilt angle after endurance showed a value exceeding the standard value of 5 mrad.

[0080]

[Table 3]

Example 4 The same as Example 3 except that a recording film made of a TbFeCo film having a thickness of 30 nm was formed by a magnetron sputtering method instead of the recording film made of the laminated film of the GdFeCo film and the TbFeCo film of Example 3. Then, a magneto-optical disk was created.

When the recording characteristics of this magneto-optical disk were examined, the saturation C / N ratio was 48 dB to 50 dB, which was almost the same as the characteristics of the magneto-optical disk of Example 3.

(Embodiment 5) In Embodiment 1, the first inorganic dielectric film and the second inorganic dielectric film were replaced by a instead of SiNx.
A magneto-optical disk was prepared and evaluated in the same manner as in Example 1 except that -Si was used.

The conditions for forming the a-Si film are as follows.

[0085]

[Table 4]

The raw material gas was introduced from the gas introduction means 25. Further, the internal stress refractive index and the film thickness unevenness of the a-Si film formed under these conditions, and the substrate temperature immediately after the film formation were measured and evaluated in the same manner as in Example 1. The results are shown in Table-3.
Shown in.

Example 6 A magneto-optical disk was manufactured in the same manner as in Example 1 except that SiO ₂ was used as the first inorganic dielectric film and the second inorganic dielectric film instead of the SiNx film in Example 1. Created and evaluated.

The SiO ₂ film forming conditions are as follows.

[0089]

[Table 5]

The internal stress, refractive index, film thickness unevenness, and substrate temperature immediately after film formation of the SiO ₂ film formed under these conditions were measured and evaluated in the same manner as in Example 1. The results are shown in Table-3.

(Embodiment 7) A phase change type optical disk was prepared in the same manner as in Embodiment 1 except that a recording film made of an Sb-Te alloy was formed by a magnetron sputtering method instead of the magneto-optical recording film of Example 1. Created. The characteristics of this optical disc were evaluated in the same manner as in Example 1. The results are shown in Table-3.

The C / N ratio of the optical disk of this example and the B.N. E. The R is measured by an optical disc evaluation device (trade name: OM
S-2000: manufactured by Nakamichi Co., Ltd. was used.

Reference Example 1 First SiN used in Example 1
The film forming devices 13 and 15 for the x film and the second SiNx film are controlled by RF.
Example 1 except that the magnetron sputtering film forming apparatus was replaced
A magneto-optical disk was prepared in the same manner as in.

The magnetron sputtering film forming apparatus is shown in FIG.
As shown in FIG. 5, a conductive backing plate 92 serving as a cathode electrode in the film forming chamber 91, an RF power source 93 for giving a predetermined sputtering power to a target 95 which is connected to the backing plate and is installed on the backing plate, and Permanent magnet 94, substrate holder 96 holding substrate 10, vacuum pump 97, and gas introduction means 9
8 is provided.

In the first reference example, the SiNx film was first evacuated to 1 × 10 ⁻⁵ Pa inside the film forming chamber and then A
r gas and N ₂ gas were introduced into the chamber, and the pressure of the mixed gas of Ar gas and N ₂ gas was 0.2 Pa (Ar: N ₂ =
20:10 SCCM) and RF power of 7 W / cm ²
Is formed by reactive sputtering. The magneto-optical disk thus obtained was evaluated in the same manner as in Example 1. As shown in Table 3, the C / N ratio and the B.N.
E. The R and tilt angles showed good characteristics even after the durability test, and the stress, the refractive index, the film thickness distribution and the substrate temperature of the SiNx film were all within the allowable range. However, the deposition rate of the SiNx film is 60-
About 100Å, which is 1/100 compared to the plasma CVD method
It was about.

Reference Example 2 In Reference Example 1, when film formation was performed with an RF power of 10 W / cm ² in order to improve the film formation rate, abnormal discharge frequently occurred and high quality without defects such as pinholes. It was difficult to form a simple dielectric film.

Further, the temperature of the substrate rises almost in proportion to the deposition rate, and at a deposition rate of 10 nm / min or more, the substrate is bent over 200 um or more, and the mechanical characteristics of the magneto-optical disk cannot be satisfied. Oops.

[0098]

[Table 6]

(Embodiment 8) In Embodiment 1, the radius of the window at the connecting portion between the plasma generating container 21 and the process container 24 is set to 7
A magneto-optical disk was prepared and evaluated in the same manner as in Example 1 except that it was set to 0 mm.

The stress, the refractive index, the film forming rate, the film thickness unevenness, and the substrate temperature of the SiNx film formed by the method of this example were measured and evaluated in the same manner as in Example 1. Table of the results
4 shows.

(Embodiment 9) The antenna 2 in Embodiment 1
A magneto-optical disk was prepared and evaluated in the same manner as in Example 1 except that the loop interval of 2 was 80 mm. In addition, the stress, the refractive index, the film formation rate, the film thickness unevenness, and the substrate temperature immediately after the film formation of the SiNx film formed by the method of this example were measured and evaluated in the same manner as in Example 1. The results are shown in Table-4.

Example 10 The substrate 10 in Example 1
The same as Example 1 except that a 3.5-inch optical disk substrate made of polycarbonate resin (trade name: Iupilon H4000; manufactured by Mitsubishi Gas Chemical Co., Inc.) having an outer diameter of 86 mm, an inner diameter of 15 mm, and a thickness of 1.2 mm is used. Then, a magneto-optical disk was prepared and evaluated.

The stress, the refractive index, the film forming rate, the film thickness unevenness, and the substrate temperature of the SiNx film formed by the method of this example were measured and evaluated in the same manner as in Example 1. The results are shown in Table-4.

(Embodiment 11) The substrate 10 in Embodiment 3
The same as Example 3 except that a 3.5-inch optical disk substrate of polycarbonate resin (trade name: Iupilon H4000; manufactured by Mitsubishi Gas Chemical Co., Inc.) having an outer diameter of 86 mm, an inner diameter of 15 mm and a thickness of 1.2 mm was used. Then, a magneto-optical disk was prepared and evaluated.

The stress, the refractive index, the film forming rate, the film thickness unevenness, and the substrate temperature of the SiNx film produced by the method of this example were measured and evaluated in the same manner as in Example 3. The results are shown in Table-4.

[0106]

[Table 7]

[0107]

As described above, according to the present invention, the protective performance of the recording layer of the dielectric film is remarkably improved within the range of the stress that the inorganic dielectric film for optical recording medium can contain. It is possible to manufacture a high quality optical recording medium.

Further, according to the present invention, the inorganic dielectric for an optical recording medium having a low internal stress and excellent recording layer protection performance while maintaining the characteristic of the plasma CVD method capable of high-speed film formation. Since the body film can be formed, a higher quality optical recording medium can be manufactured at low cost.

Further, according to the present invention, high-speed film formation of an inorganic dielectric film for an optical recording medium, which has a low internal stress and an excellent recording layer protection performance, can be performed while suppressing a temperature rise of the substrate. It is possible to manufacture an optical recording medium with little deformation and excellent in shape stability.

Furthermore, according to the present invention, ECR plasma CV
Compared to the D device, a high-quality inorganic dielectric film for an optical recording medium can be formed by using a low frequency RF current and a weak magnetic field, and the cost of the high-performance optical recording medium can be reduced. it can.

[Brief description of drawings]

FIG. 1 is a schematic plan view of an embodiment of an apparatus for manufacturing an optical recording medium according to the present invention.

FIG. 2 is a schematic cross-sectional view of an embodiment of an inorganic dielectric film forming apparatus in the apparatus of FIG.

3 is a schematic cross-sectional view of another embodiment of the apparatus for depositing an inorganic dielectric film in the apparatus of FIG.

FIG. 4 is a schematic sectional view of an optical recording medium.

5A is a schematic view of an embodiment of an antenna that can be used in the film forming apparatus of FIG. 2 or FIG. (B) A schematic view of another embodiment of an antenna that can be used in the film forming apparatus of FIG. 2 or 3. (C) A schematic view of another embodiment of an antenna that can be used in the film forming apparatus of FIG. 2 or 3.

6A is a schematic cross-sectional view of another embodiment of the inorganic dielectric film forming apparatus in the apparatus of FIG. 6B is a sectional view taken along line AA of FIG.

FIG. 7A is a schematic explanatory diagram of a substrate installation area on a substrate holder. (B) A schematic plan view showing a substrate installation area of the substrate holder.

FIG. 8 is a schematic sectional view of an ECR plasma CVD film forming apparatus.

FIG. 9 is a schematic cross-sectional view of an RF magnetron sputtering film forming apparatus.

[Explanation of symbols]

 10 substrate 11 substrate charging chamber 12 degassing chamber 13, 15 inorganic dielectric film deposition chamber 14 recording film deposition chamber 16 reflective film deposition chamber 17 extraction chamber 18 substrate holder 21 plasma generation container 22 antenna 23 coil 24 Process container 25 Gas introduction means 26 Gas introduction means 27 Substrate holding means 28 Matching box 29 RF power source 30 Vacuum pump 41 Recording film 42, 43 Inorganic dielectric film 44 Reflective film 61 Permanent magnet 71, 72 Substrate arrangement area on substrate holding means 81 Microwave Waveguide 82 Plasma Generation Container 83 Coil 84 Process Container 91 Film Forming Chamber 92 Batching Plate 93 RF Power Source 94 Permanent Magnet 95 Target 96 Substrate Holder 97 Vacuum Pump 98 Gas Introducing Means

Front Page Continuation (72) Inventor Akio Koganei 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kazuki Motomoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (26)

[Claims] 1. A method of manufacturing an optical recording medium having a laminated film of a recording film and an inorganic dielectric film on a substrate, wherein the inorganic dielectric film is formed by using a helicon wave plasma CVD method. And a method for manufacturing an optical recording medium. 2. A step of providing a plasma generation container in which the helicon wave plasma CVD method extends along a predetermined axis and a process container arranged adjacent to the plasma generation container along the axis; Disposing the substrate in a container so that its surface is orthogonal to the axis; introducing at least one of a reaction gas and a source gas into the plasma generation container; and a high-frequency electric field in the plasma generation container and 2. The method of manufacturing an optical recording medium according to claim 1, further comprising the steps of: generating a magnetic field in a direction along the axis to convert the gas in the plasma generating container into plasma. 3. The method of manufacturing an optical recording medium according to claim 2, wherein the high frequency electric field is generated by an antenna arranged around the plasma generating container. 4. The high frequency of the high frequency electric field is 10 to 30 MH.
The method of manufacturing an optical recording medium according to claim 2, wherein z is z. 5. The method of manufacturing an optical recording medium according to claim 2, wherein the magnetic field strength (G) satisfies the following condition in the central portion of the plasma generating container. 0 <G ≦ 500 gauss 6. The method of manufacturing an optical recording medium according to claim 2, wherein the magnetic field strength (G) satisfies the following condition in the central portion of the plasma generating container. 0 <G ≦ 200 gauss 7. The method of manufacturing an optical recording medium according to claim 2, wherein the magnetic field strength (G) satisfies the following condition in the central portion of the plasma generating container. 10 <G ≦ 100 gauss 8. The method of manufacturing an optical recording medium according to claim 2, wherein the magnetic field is generated by a coil arranged around the plasma generating container. 9. The method of manufacturing an optical recording medium according to claim 3, wherein the antenna has an arrangement such that two separate loops surrounding the plasma generating container are drawn. 10. The antenna, wherein the loop interval is 1
The method for manufacturing an optical recording medium according to claim 9, wherein an antenna having a size of 00 to 500 mm is used. 11. The loop spacing of the antenna is 1
The method for manufacturing an optical recording medium according to claim 10, wherein an antenna having a size of 00 to 250 mm is used. 12. The method for manufacturing an optical recording medium according to claim 9, wherein high frequency currents are passed through the loop in opposite directions. 13. The method of manufacturing an optical recording medium according to claim 1, wherein the inorganic dielectric film is a Si-based semiconductor film. 14. At least one selected from inorganic silanes, organic silanes, and halosilanes as the source gas.
3. The method for manufacturing an optical recording medium according to claim 2, wherein an inorganic dielectric film containing a Si-based semiconductor is formed by using one of the two. 15. The method of manufacturing an optical recording medium according to claim 1, wherein the inorganic dielectric film is a Si-based compound film. 16. A method of forming at least one gas selected from inorganic silanes, organic silanes, and halosilanes as a raw material gas, and forming an inorganic dielectric film containing a Si-based compound using a reaction gas. Item 2. A method for manufacturing an optical recording medium according to item 2. 17. The method of manufacturing an optical recording medium according to claim 1, wherein the inorganic dielectric film is a metal compound film. 18. The optical recording medium according to claim 2, wherein at least one gas selected from organic metals and metal halides is used as the source gas, and an inorganic dielectric film containing a metal compound is formed using a reaction gas. Manufacturing method. 19. The method of manufacturing an optical recording medium according to claim 2, wherein a reaction gas is introduced into the plasma generation container and the source gas is introduced into the process container. 20. The method of manufacturing an optical recording medium according to claim 2, wherein a film is formed by generating a magnetic field near the inner wall of the process container. 21. The method of manufacturing an optical recording medium according to claim 20, wherein a permanent magnet is arranged on the outer wall of the process container to generate the magnetic field. 22. The optical recording medium according to claim 21, wherein the magnets are arranged so that the same poles extend along the axial direction of the process container and the different poles are alternately arranged in the circumferential direction of the process container. Production method. 23. The method of manufacturing an optical recording medium according to claim 1, wherein the recording film contains at least one of a rare earth element and a transition metal. 24. The method of manufacturing an optical recording medium according to claim 1, wherein the recording film is an amorphous magnetic recording film containing a rare earth and a transition metal. 25. The method of manufacturing an optical recording medium according to claim 1, wherein the recording film contains a chalcogenide element. 26. An optical recording medium having a laminated film of a recording film and an inorganic dielectric film on a substrate, wherein the inorganic dielectric film is formed by a helicon wave plasma CVD method. recoding media.