JPH0863792A - Optical disk and its production - Google Patents

Abstract

PURPOSE: To obtain an optical disk having high accuracy and excellent reliability by providing this optical disk with a sectional structure formed by sticking a pair of transparent substrates formed with at least one layer of recording films on information pattern layers with adhesives. CONSTITUTION: This disk has a disk shape bored with a hole 34 at its center. The optical disk is arranged in the spacing between a pair of the substrates facing each other and consists of the cured matter of the two-part curing type silicone adhesives. The substrates 3 have the transparent replica substrates 1 and metallic films (recording films) 2 for recording and are disposed to face each other in such a manner that the recording films 2 exist on the inner side. The substrates 1 are medium to allow transmission of lasers for recording and reproducing. Glass, polyolefin, etc., which are optically isotropic and have optical distortions of, for example, <=50nm are used for this purpose. The recording films 2 correspond to a light spot diameter of, for example, 0.6 to 1μm. As a result, the optical disk having the high accuracy and the excellent reliability is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk suitable for storing, recording and reproducing voice, image, information and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art An optical disc has a recording metal film formed on a transparent replica substrate such as glass or transparent plastic having groove-shaped or hole-shaped irregularities for servo tracks, and the transparent replica substrate is used for recording. They are formed by facing each other with a constant gap so that the metal film is on the inside, and pasted together with an adhesive.

In the conventional optical disk manufacturing method, a hot melt adhesive or a chemically reactive adhesive is used for bonding a transparent replica substrate. Hot melt adhesives are excellent in terms of simplification of manufacturing workability and cost reduction,
In JP-A-63-67238, a thermoplastic hot melt adhesive is used.

Further, the chemical reaction type adhesive has an effect of suppressing the deformation of the disk and has a one-component anaerobic curing type adhesive (described in JP-A-61-151853).
Liquid non-mixing type adhesive (described in Japanese Patent Laid-Open No. 61-50231) and one-component moisture-curing adhesive (described in Polymer 24, February issue (1993) 111p). Was used.

In recent years, demands for increasing the amount of information to be recorded and increasing the processing speed of optical discs are rapidly increasing in recent years. In order to meet these requirements, it is necessary to increase the storage capacity and rotate the disk at high speed.

[0006]

However, the above-mentioned adhesive has the following problems. Thermoplastic hot-melt adhesives have defects due to heat during adhesive application or pressure during bonding, or plasticity or elastic deformation during high-speed rotation, or deformation or peeling due to aging during storage. Will end up.

The one-component anaerobic curable adhesive has a short curing time of seconds and is bonded and cured under normal pressure. For this reason, bubbles are easily mixed, and the mixed bubbles are hard to come off, and the mixture is cured with the bubbles mixed therein. Further, since the cured product obtained by curing is hard, the bubbles cannot be sufficiently absorbed and relaxed, resulting in defects such as poor disk flatness and the uncured product in the bubble portion corroding the recording layer.

When a two-liquid non-mixing type adhesive is used, the two liquids are sequentially applied separately in a film thickness of several tens of μm, and pressure is applied to bond the substrates. When such a bonding method is adopted, unevenness in curing will occur due to the pressure at the time of bonding. This is because the coating film of the adhesive becomes non-uniform. Such uneven curing causes wrinkles in the recording layer, which causes defective recording and reproduction.

The one-component moisture-curable adhesive is one in which a reaction is initiated by the surrounding moisture to make the adhesive surface tacky. When the adhesive is used, the adhesive is applied to the substrate and then adhered before the tackiness is lost. Since the one-component moisture-curable adhesive reacts with ambient moisture, it is difficult to control the curing and the workability is poor. Further, the curing speed of the adhesive after bonding is extremely slow, which causes deformation of the disk.

As described above, when a thermoplastic hot melt adhesive is used, defects may occur during the manufacture of optical disks. Furthermore, when using the optical disc,
Deformation may occur due to high-speed access and high-speed rotation. Further, when the optical disc is stored, it may be deformed or peeled off due to aging. Also, 1
Liquid anaerobic curable adhesive, 2-liquid non-mixing adhesive, or
When using a one-part moisture-curing adhesive,
Although there is no problem during storage, there is a problem that defects will occur during the manufacture of optical discs.

Therefore, an object of the present invention is to provide an optical disk and a method for manufacturing the optical disk, in which defects during manufacturing of the optical disk and deformation and peeling due to aging during storage of the optical disk are reduced.

[0012]

In order to achieve the above object, the present invention has a pair of opposing substrates and an adhesive layer, at least one of which has a recording film, and the adhesive layer is In the optical disc disposed in the gap between the pair of opposed substrates, the adhesive layer contains a two-component curable silicone resin. The adhesive layer preferably has a viscosity of 10 to 700 poise, and the cured resin preferably has a hardness of 20 to 80 (JIS A).

Further, in the present invention, an adhesive application step of applying an adhesive to two transparent substrates having a recording layer formed on at least one side to form an adhesive layer, and the adhesive layer is placed inside. A method of manufacturing an optical disk, comprising a step of adhering the two transparent substrates so as to face each other and pressurizing and adhering them, wherein the adhesive contains a two-component curable silicone adhesive. To do. It is desirable that the adhesive has a viscosity of 10 to 700 poise and a hardness after curing of 20 to 80 (JIS A). In addition, the pressure applied in the bonding step is 0.4 to 0.8 kg.
/ Cm2 is desirable. Furthermore, it is desirable that the bonding step be performed in a reduced pressure atmosphere of 1 to 20 Torr.

[0014]

According to the present invention, when an optical disk is manufactured, a two-component mixed type silicone adhesive having a viscosity of 10 to 700 poise and a hardness after curing of 20 to 80 (JIS A) is used for adhering a substrate. By doing so, the adhesive layer is uniformly hardened and corrosion of the recording film due to the uncured material can be eliminated.

It is desirable that the adhesive be cured after completion of the reaction evenly after the bonding. This is to avoid residual uncured material due to non-uniform reaction. If the adhesive layer reacts nonuniformly and the uncured material remains, the uncured material causes corrosion of the recording film. One-component moisture-curable adhesives that react and cure with the humidity of the outside air will cure relatively quickly because the inner and outer peripheries of the substrate are in contact with the outside air, but the middle circumference will not easily get moisture. The reaction of the parts is slow and the curing is insufficient, and the uncured product remains. Therefore, in the present invention, a two-component adhesive agent using a curing agent is used. In addition, the viscosity of the adhesive is such that the adhesive layer can be uniformly formed on the substrate without uneven coating, uneven flow of the adhesive at the time of bonding can be eliminated, and unevenness of the substrate can be prevented, and the adhesive effect As a result, it is possible to reduce the displacement of the substrate before the curing after the bonding. Further, the hardness after curing absorbs and relaxes strains due to bubbles mixed in the adhesive layer and uneven reaction, and thus it is possible to prevent unevenness of the substrate from occurring.

The pressure applied to the substrates at the time of bonding is
It is desirable to set it to 0.4 to 0.8 kg / cm 2. It is possible to eliminate poor adhesion of the substrate due to insufficient pressure and flow of the adhesive due to high pressure.

It is desirable that the bonding step is performed in a reduced pressure atmosphere. This is to prevent air bubbles from being mixed into the adhesive layer and to prevent uncured substances from being generated, and further to promote the release of air bubbles once mixed. In an atmospheric pressure atmosphere, the inclusion of air bubbles has a bad influence on the recording film.

Next, the two-part curable silicone adhesive used for the optical disk of the present invention will be described in detail. The two-component curing type silicone adhesive is composed of a main agent and a curing agent,
When used as an adhesive for optical disks, it mixes before application and the two liquids react and cure, and are superior in adhesive strength, heat resistance, and mechanical strength compared to thermoplastic hot-melt adhesives. Since it has excellent heat resistance, it is suitable for various environments, has excellent mechanical strength, and in particular, it is possible to obtain an extremely reliable optical disk that has little adverse effect on the recording film and does not corrode.

The combination of the two-component components includes a base polymer and a cross-linking agent as main components, a curing catalyst as a curing agent, a base polymer as a main component, a crosslinking agent and a curing catalyst as a curing agent, a base polymer and a curing catalyst as a main component, and a curing agent. There are three types of crosslinking agents.

In the constitution of the above-mentioned two-component curable silicone adhesive, the base polymer is a diorganopolysiloxane having a functional group at the terminal, and the base polymer is three-dimensionally crosslinked.
A cross-linking agent such as silane or siloxane having a functionality or more, and a curing catalyst for reacting the base polymer with the cross-linking agent are separately liquefied and used. In addition, you may mix | blend these with a filler and other additives, and may use them. Examples of the above-mentioned base polymer include terminal hydroxy-modified methyl polysiloxane, terminal hydroxy-modified phenyl polysiloxane, terminal vinyl group-modified methyl polysiloxane, terminal vinyl group-modified phenyl polysiloxane, terminal hydrogenated methyl polysiloxane,
Examples include hydrogenated phenyl polysiloxane.

Examples of the cross-linking agent include tetramethoxysilane, tetraethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, dimethylaminotrimethoxysilane and dimethylaminotriethoxysilane.

Further, exemplifying the above-mentioned curing catalyst,
There are tin compounds for dealcoholization reaction, platinum compounds for dehydrogenation reaction, tin compounds, and platinum compounds for addition reaction.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic diagram of the optical disk of the present invention. The optical disk has a disk shape with a hole 34 in the center.
It is shown as a partial sectional view. 2 is a sectional view taken along the line AB in FIG. The optical disks of the following examples are arranged in the gap between a pair of opposing substrates 3 and are made of a cured product of a two-component curable silicone adhesive. The substrate 3 has a transparent replica substrate 1 and a recording metal film (recording film) 2 and faces each other with the recording film 2 inside. In each of the following examples, two substrates 3 having the same unevenness and recording film are bonded to each other to manufacture an optical disc capable of recording information on both sides. However, one substrate is
It is not necessary to have the unevenness or the recording film 2. In this case, data can be recorded on only one side.

The transparent replica substrate 1 is a medium through which a laser for recording / reproducing is transmitted. For this reason, it is necessary to have characteristics such that it is optically isotropic and has an optical strain of 50 nm or less, which is a measure of optical characteristics. The type is not particularly limited,
For example, a glass substrate, a polymethylmethacrylate substrate, a polycarbonate substrate, a polyolefin substrate, a heat or light curing resin substrate, or the like can be given. The recording film 2 is 0.6 to 1
The type is not particularly limited as long as it corresponds to an optical spot diameter of about μm and does not change the shape of the recording film such as phase change or magneto-optical property and forms a recording domain. For example, tellurium oxide film (TeOx), SbSe / BiT
e Laminated film, rare earth-transition metal amorphous alloy, TbF
eCo-based oxide film, GdTbFe-based oxide film, DyFeCo
System oxide film, TbDyFeCo system oxide film, garnet system oxide film, Pt / Co laminated material, GeSbTe, InSeT
Examples include eCo, InSbTe, and In-Sb alloys.

In the following examples, a two-component curable silicone adhesive manufactured by Toray Silicone Co., Ltd. was used. The characteristics of each adhesive in Examples 1 to 10 are shown in (Table 1).

[0027]

[Table 1]

In each of the embodiments described below, a stamper is used to manufacture an optical disc. In addition, the stamper has an uneven shape corresponding to the information pattern,
The type of the uneven surface is not particularly limited as long as it is a copy type having excellent releasability. For example, any of an electroformed stamper, a resin stamper, a glass stamper, etc. may be used. The stamper used in each example is for the optical disc having an outer diameter of 300 mm shown in FIG. 3 and the optical disc having an outer diameter of 130 mm shown in FIG. 4 (a).
It manufactured according to the manufacturing method of- (f).

The stamper for an optical disc having an outer diameter of 300 mm is a glass disk 17 having both sides polished (outer diameter: 350 m).
m, inner diameter: 10 mm, thickness: 10 mm) is prepared (a). Next, a positive type photoresist is spin-coated on the polished one side of the glass disk 17 to form a photoresist film 16 having a film thickness of 0.14 μm (b). Then, an information signal is written from the recording device to the photoresist film 16 by using an Ar laser (wavelength: 458 nm), and the photoresist film is developed to form irregularities of grooves or pits representing the information signal (c). In the optical disc manufactured in this example, the irregularities represent auxiliary information for reading information recorded on the recording film, such as an address. The Ni film 5 having a thickness of 40 nm is formed on the photoresist film 16 having the irregularities formed as described above by a vacuum vapor deposition method (d). Furthermore, the Ni film 5
Ni as an electrode, an Ni electroformed film 6 having a thickness of 300 μm was formed by an electrolytic plating method (e), and the glass disk 17 and the Ni film 5 were peeled off to form a Ni stamper 7 (f). .

The stamper for an optical disc having an outer diameter of 130 mm is a glass disk 17 having both sides polished (outer diameter: 200 m).
m, inner diameter: 5 mm, thickness: 10 mm) is prepared (a). Next, a positive type photoresist is spin-coated on the polished one side of the glass disk 17 to form a photoresist film 16 having a film thickness of 0.14 μm (b). Then, an information signal is written from the recording device to the photoresist film 16 by using an Ar laser (wavelength: 458 nm), and the photoresist film is developed to form irregularities of grooves or pits representing the information signal (c). In the optical disc manufactured in this example, the irregularities represent auxiliary information for reading information recorded on the recording film, such as an address. The Ni film 5 having a thickness of 40 nm is formed on the photoresist film 16 having the irregularities formed as described above by a vacuum vapor deposition method (d). Furthermore, the Ni film 5
Ni as an electrode, an Ni electroformed film 6 having a thickness of 300 μm was formed by an electrolytic plating method (e), and the glass disk 17 and the Ni film 5 were peeled off to form a Ni stamper 7 (f). .

(Examples 1 and 2) As the adhesive, the adhesives described in the columns of Examples 1 and 2 in Table 1 were used to manufacture optical disks as follows. The manufacturing method is shown in FIG. In this embodiment, a polycarbonate resin replica substrate 1 is used.
By adjusting the SiN enhance film 12 as the recording film 2,
TbFeCo magnetic film 13, AlN reflective film 14, and
Four layers of the SiN protective film 15 were formed on the replica substrate 1 and adhered using the above adhesive to obtain an optical disc.

First, a 130 mm Ni stamper 7 is prepared (a). The stamper 7 is replaced with a molding die 8 having an injection hole.
Then, the polycarbonate resin 10 (molecular weight: about 15000) is heated and melted and injected into the gap 9 in the molding die 8 (b). The gap 9 has a disk shape with an outer diameter of 130 mm and a thickness of 1.2 mm, and has a central hole with an inner diameter of 15 mm at the center (that is, the molding die 8 has an outer diameter of 15 mm at the center). Has a cylindrical protrusion (not shown) of
By removing the stamper 7 and the molding die 8, the replica substrate 1 made of a polycarbonate resin (outer diameter: 130 mm, center hole diameter: 1) on which the grooves and pits of the stamper 7 are transferred
5 mm, thickness: 1.2 mm) can be obtained (c).

Then, on the surface (information pattern surface) on which the unevenness of the obtained replica substrate 1 is transferred, the SiN enhance film 12 (thickness: 30 nm) and the TbFeCo magnetic film 13 are formed.
(Thickness: 30 nm), AlN reflective film 14 (thickness: 30 n
m) and the SiN protective film 15 (thickness: 30 nm) were sequentially formed by the sputtering method to form the recording film 2 and the substrate 3 was obtained (d).

On the recording film of the substrate 3 produced as described above, an adhesive obtained by mixing the main component of the two-component curable silicone adhesive of Examples 1 to 3 in Table 1 and the curing agent was applied by spin coating. It was applied to form an adhesive layer 4 having a thickness of 30 μm (e). Further, this step was repeated to produce another substrate 3 having the adhesive layer 4 formed thereon.

Next, the substrate 3 is placed in the closed container 21 with the adhesive layer 4 inside and the gap 35 between the substrates 3 is 5 m.
The pressure inside the closed container 21 is reduced to 1 Torr in order to create a reduced pressure atmosphere (f).

Thereafter, the adhesive layers of the two substrates 3 were brought into contact with each other, and a pressure of 0.4 kg / cm 2 was applied for 5 seconds to bond them (g). Finally, it was taken out from the container 21 to obtain an optical disc having two substrates 3 and an adhesive layer 2.

(Example 3) An optical disk was manufactured as follows by using the adhesive described in the column of Example 3 in Table 1 as the adhesive. The manufacturing method is shown in FIG. In this embodiment, the replica substrate 1 made of a polycarbonate resin is prepared, and the recording film 2 includes the SiN enhance film 12 and TbF.
eCo magnetic film 13, AlN reflective film 14, and SiN
Four layers of the protective film 15 were formed on the replica substrate 1 and adhered using the above adhesive to obtain an optical disc.

First, a 300 mm Ni stamper 7 is prepared (a). The stamper 7 is replaced with a molding die 8 having an injection hole.
Then, the polycarbonate resin 10 (molecular weight: about 15000) is heated and melted and injected into the gap 9 in the molding die 8 (b). The gap 9 has a disk shape with an outer diameter of 300 mm and a thickness of 1.2 mm, and has a central hole with an inner diameter of 35 mm at the center (that is, the molding die 8 has an outer diameter of 35 mm at the center). Has a cylindrical protrusion (not shown) of
If the stamper 7 and the molding die 8 are removed, the replica substrate 1 made of a polycarbonate resin (outer diameter: 300 mm, center hole diameter: 3) on which the grooves and pits of the stamper 7 are transferred.
5 mm, thickness: 1.2 mm) can be obtained (c).

Then, on the surface (information pattern surface) on which the unevenness of the obtained replica substrate 1 is transferred, a SiN enhance film 12 (thickness: 30 nm) and a TbFeCo magnetic film 13 are formed.
(Thickness: 30 nm), AlN reflective film 14 (thickness: 30 n
m) and the SiN protective film 15 (thickness: 30 nm) were sequentially formed by the sputtering method to form the recording film 2 and the substrate 3 was obtained (d).

On the recording film of the substrate 3 produced as described above, an adhesive obtained by mixing the main component of the two-component curable silicone adhesive of Examples 1 to 3 in Table 1 and the curing agent was applied by spin coating. It was applied to form an adhesive layer 4 having a thickness of 30 μm (e). Further, this step was repeated to produce another substrate 3 having the adhesive layer 4 formed thereon.

Next, the substrate 3 is placed in the closed container 21 with the adhesive layer 4 inside, and the gap 35 between the substrates 3 is 5 m.
The pressure inside the closed container 21 is reduced to 1 Torr in order to create a reduced pressure atmosphere (f).

Then, the adhesive layers of the two substrates 3 were brought into contact with each other, and a pressure of 0.4 kg / cm 2 was applied for 5 seconds to bond them (g). Finally, it was taken out from the container 21 to obtain an optical disc having two substrates 3 and an adhesive layer 2.

(Examples 4 to 5) As the adhesive, the adhesives described in the columns of Examples 4 to 5 in Table 1 were used to manufacture optical disks as follows. The manufacturing method is shown in FIG. In this embodiment, a replica substrate 1 made of an ultraviolet curable resin and a plastic plate is prepared, and the recording film 2 is made of GeSb.
Te recording film 25, SbBi reflective film 26, SiN protective film 2
A three-layer film of No. 7 was formed on the replica substrate 1 and adhered using the above adhesive to obtain an optical disc.

First, a 130 mm Ni stamper 7 is prepared (a). An ultraviolet curable resin 22 (viscosity: 200 cp) is dropped on the uneven surface of the stamper 7 to form a plastic plate 2
3 (outer diameter: 130 mm, inner diameter: 15 mm, thickness: 1.1
mm), the UV curable resin 22 is spread so as to have a thickness of 80 μm. Next, using the ultraviolet irradiation device 20, from the plastic plate side, 30 seconds, 100 mW / cm
^The ultraviolet curable resin 22 is irradiated with ultraviolet rays of intensity ²
Is cured (b). Stamper 7 and UV curable resin 2
When the gap between the two is peeled off, the replica substrate 1 in which the grooves and pits of the stamper 7 are transferred is obtained (c).

On the information pattern surface of the replica substrate 1,
GeSbTe recording film 25 (thickness: 30 nm), SbBi
A reflective film 26 (thickness: 20 nm) and a SiN protective film 27 (thickness: 30 nm) were sequentially formed by a sputtering method to prepare a substrate 3 having a recording film 28 formed on the replica substrate 1 (d). .

On the recording film of the substrate 3 produced as described above, an adhesive obtained by mixing the main component of the two-component curable silicone adhesive of Examples 4 to 6 in Table 1 and the curing agent was applied by spin coating. It was applied to form an adhesive layer 4 having a thickness of 30 μm (e). Further, this step was repeated to produce another substrate 3 having the adhesive layer 4 formed thereon.

Next, the substrate 3 is placed in the closed container 21 with the adhesive layer 4 inside and the gap 35 between the substrates 3 is 5 m.
The pressure inside the closed container 21 is reduced to 1 Torr in order to create a reduced pressure atmosphere (f).

Then, the adhesive layers of the two substrates 3 were brought into contact with each other, and a pressure of 0.4 kg / cm 2 was applied for 5 seconds to bond them (g). Finally, it was taken out from the container 21 to obtain an optical disc having two substrates 3 and an adhesive layer 2 (i).

(Example 6) An optical disk was manufactured as follows by using the adhesive described in the column of Example 6 in Table 1 as the adhesive. The manufacturing method is shown in FIG. In this embodiment, a replica substrate 1 made of an ultraviolet curable resin and a plastic plate is prepared, and as the recording film 2, three layers of a GeSbTe recording film 25, an SbBi reflective film 26, and a SiN protective film 27 are formed on the replica substrate 1. Then, the optical disc was obtained by bonding with the above adhesive.

First, a 300 mm Ni stamper 7 is prepared (a). An ultraviolet curable resin 22 (viscosity: 200 cp) is dropped on the uneven surface of the stamper 7 to form a plastic plate 2
3 (outer diameter: 300 mm, inner diameter: 35 mm, thickness: 1.1
mm), the UV curable resin 22 is spread so as to have a thickness of 80 μm. Next, using the ultraviolet irradiation device 20, from the plastic plate side, 30 seconds, 100 mW / cm
^The ultraviolet curable resin 22 is irradiated with ultraviolet rays of intensity ²
Is cured (b). Stamper 7 and UV curable resin 2
When the gap between the two is peeled off, the replica substrate 1 in which the grooves and pits of the stamper 7 are transferred is obtained (c).

On the information pattern surface of the replica substrate 1,
GeSbTe recording film 25 (thickness: 30 nm), SbBi
A reflective film 26 (thickness: 20 nm) and a SiN protective film 27 (thickness: 30 nm) were sequentially formed by a sputtering method to prepare a substrate 3 having a recording film 28 formed on the replica substrate 1 (d). .

On the recording film of the substrate 3 produced as described above, an adhesive obtained by mixing the main component of the two-component curable silicone adhesive of Examples 4 to 6 in Table 1 and the curing agent was applied by spin coating. It was applied to form an adhesive layer 4 having a thickness of 30 μm (e). Further, this step was repeated to produce another substrate 3 having the adhesive layer 4 formed thereon.

Next, the substrate 3 is placed in the closed container 21 with the adhesive layer 4 inside, and the gap 35 between the substrates 3 is 5 m.
The pressure inside the closed container 21 is reduced to 1 Torr in order to create a reduced pressure atmosphere (f).

Thereafter, the adhesive layers of the two substrates 3 were brought into contact with each other, and a pressure of 0.4 kg / cm 2 was applied for 5 seconds to bond them (g). Finally, it was taken out from the container 21 to obtain an optical disc having two substrates 3 and an adhesive layer 2 (i).

(Example 7) An optical disk was manufactured as follows by using the adhesive described in the column of Example 7 in Table 1 as the adhesive. The manufacturing method is shown in FIG. In this embodiment, the polycarbonate resin replica substrate 1 is adjusted so that the recording film 2 is formed of GeSbTe recording films 25 and SbB.
An i-reflective film 26 and a SiN protective film 27 having three layers were formed on the replica substrate 1 and adhered using the above adhesive to obtain an optical disc.

First, a 130 mm Ni stamper 7 is prepared (a). The stamper 7 is replaced with a molding die 8 having an injection hole.
Then, the polycarbonate resin 10 (molecular weight: about 15000) is heated and melted and injected into the gap 9 in the molding die 8 (b). The gap 9 has a disk shape with an outer diameter of 130 mm and a thickness of 1.2 mm, and has a central hole with an inner diameter of 15 mm at the center (that is, the molding die 8 has an outer diameter of 15 mm at the center). Has a cylindrical protrusion (not shown) of
By removing the stamper 7 and the molding die 8, the replica substrate 1 made of a polycarbonate resin (outer diameter: 130 mm, center hole diameter: 1) on which the grooves and pits of the stamper 7 are transferred
5 mm, thickness: 1.2 mm) can be obtained (c).

On the information pattern surface of the replica substrate 1,
GeSbTe recording film 25 (thickness: 30 nm), SbBi
A reflective film 26 (thickness: 20 nm) and a SiN protective film 27 (thickness: 30 nm) were sequentially formed by a sputtering method to form a recording film 2 and a substrate 3 was obtained (d).

On the recording film of the substrate 3 produced as described above, an adhesive obtained by mixing the main component of the two-component curable silicone adhesive of Examples 7 and 8 in Table 1 and the curing agent was applied by spin coating. It was applied to form an adhesive layer 4 having a thickness of 30 μm (e). Further, this step was repeated to produce another substrate 3 having the adhesive layer 4 formed thereon.

Next, the substrate 3 is placed in the closed container 21 with the adhesive layer 4 inside, and the gap 35 between the substrates 3 is 5 m.
The pressure inside the closed container 21 is reduced to 1 Torr in order to create a reduced pressure atmosphere (f).

Thereafter, the adhesive layers of the two substrates 3 were brought into contact with each other, and a pressure of 0.4 kg / cm 2 was applied for 5 seconds to bond them (g). Finally, it was taken out from the container 21 to obtain an optical disc having two substrates 3 and an adhesive layer 2.

Example 8 An optical disk was manufactured as follows by using the adhesive described in the column of Example 8 in Table 1 as the adhesive. The manufacturing method is shown in FIG. In this embodiment, the polycarbonate resin replica substrate 1 is adjusted so that the recording film 2 is formed of GeSbTe recording films 25 and SbB.
An i-reflective film 26 and a SiN protective film 27 having three layers were formed on the replica substrate 1 and adhered using the above adhesive to obtain an optical disc.

First, a 300 mm Ni stamper 7 is prepared (a). The stamper 7 is replaced with a molding die 8 having an injection hole.
Then, the polycarbonate resin 10 (molecular weight: about 15000) is heated and melted and injected into the gap 9 in the molding die 8 (b). The gap 9 has a disk shape with an outer diameter of 300 mm and a thickness of 1.2 mm, and has a central hole with an inner diameter of 35 mm at the center (that is, the molding die 8 has an outer diameter of 35 mm at the center). Has a cylindrical protrusion (not shown) of
If the stamper 7 and the molding die 8 are removed, the replica substrate 1 made of a polycarbonate resin (outer diameter: 300 mm, center hole diameter: 3) on which the grooves and pits of the stamper 7 are transferred.
5 mm, thickness: 1.2 mm) can be obtained (c).

On the information pattern surface of the replica substrate 1,
GeSbTe recording film 25 (thickness: 30 nm), SbBi
A reflective film 26 (thickness: 20 nm) and a SiN protective film 27 (thickness: 30 nm) were sequentially formed by a sputtering method to form a recording film 2 and a substrate 3 was obtained (d).

On the recording film of the substrate 3 produced as described above, an adhesive obtained by mixing the main component of the two-component curable silicone adhesives of Examples 7 and 8 in Table 1 and the curing agent was applied by spin coating. It was applied to form an adhesive layer 4 having a thickness of 30 μm (e). Further, this step was repeated to produce another substrate 3 having the adhesive layer 4 formed thereon.

Next, the substrate 3 is placed in the closed container 21 with the adhesive layer 4 inside, and the gap 35 between the substrates 3 is 5 m.
The pressure inside the closed container 21 is reduced to 1 Torr in order to create a reduced pressure atmosphere (f).

Thereafter, the adhesive layers of the two substrates 3 were brought into contact with each other, and a pressure of 0.4 kg / cm 2 was applied for 5 seconds to bond them (g). Finally, it was taken out from the container 21 to obtain an optical disc having two substrates 3 and an adhesive layer 2.

(Example 9) An optical disk was manufactured as follows using the adhesive described in the column of Example 9 in Table 1 as the adhesive. The manufacturing method is shown in FIG. In this embodiment, a replica substrate 1 made of an ultraviolet curable resin and a plastic plate is prepared, and as the recording film 2, a SiN enhance film 12, a TbFeCo magnetic film 13, an AlN reflective film 1 are used.
4 and 4 layers of SiN protective film 15 were formed on replica substrate 1 and adhered using the above-mentioned adhesive to obtain an optical disc.

First, a Ni stamper 7 for 130 mm is prepared (a). An ultraviolet curable resin 22 (viscosity: 200 cp) is dropped on the uneven surface of the stamper 7 to form a plastic plate 2
3 (outer diameter: 130 mm, inner diameter: 15 mm, thickness: 1.1
mm), the UV curable resin 22 is spread so as to have a thickness of 80 μm. Next, using the ultraviolet irradiation device 20, from the plastic plate side, 30 seconds, 100 mW / cm
^The ultraviolet curable resin 22 is irradiated with ultraviolet rays of intensity ²
Is cured (b). Stamper 7 and UV curable resin 2
When the gap between the two is peeled off, the replica substrate 1 in which the grooves and pits of the stamper 7 are transferred is obtained (c).

On the information pattern surface of the replica substrate 1,
SiN enhance film 12 (thickness: 30 nm), TbFe
Co magnetic film 13 (thickness: 30 nm), AlN reflective film 14
(Thickness: 30 nm), SiN protective film 15 (thickness: 30 n
Substrate 3 in which the recording film 28 was formed on the replica substrate 1 was manufactured (d).

On the recording film of the substrate 3 produced as described above, an adhesive prepared by mixing the main component of the two-component curable silicone adhesive of Examples 9 and 10 in Table 1 and the curing agent was applied by spin coating. It was applied to form an adhesive layer 4 having a thickness of 30 μm (e). Further, this step was repeated to produce another substrate 3 having the adhesive layer 4 formed thereon.

Next, the substrate 3 is placed in the closed container 21 with the adhesive layer 4 inside, and the gap 35 between the substrates 3 is 5 m.
The pressure inside the closed container 21 is reduced to 1 Torr in order to create a reduced pressure atmosphere (f).

Thereafter, the adhesive layers of the two substrates 3 were brought into contact with each other, and a pressure of 0.4 kg / cm 2 was applied for 5 seconds to bond them (g). Finally, it was taken out from the container 21 to obtain an optical disc having two substrates 3 and an adhesive layer 2 (i).

Example 10 An optical disk was manufactured as follows, using the adhesive described in the column of Example 10 in Table 1 as the adhesive. The manufacturing method is shown in FIG. In this example, a replica substrate 1 made of an ultraviolet curable resin and a plastic plate was prepared, and four layers of a recording film 2, a SiN enhance film 12, a TbFeCo magnetic film 13, an AlN reflective film 14, and a SiN protective film 15 were prepared. Was formed on the replica substrate 1 and adhered using the above adhesive to obtain an optical disc.

First, a 300 mm Ni stamper 7 is prepared (a). An ultraviolet curable resin 22 (viscosity: 200 cp) is dropped on the uneven surface of the stamper 7 to form a plastic plate 2
3 (outer diameter: 300 mm, inner diameter: 35 mm, thickness: 1.1
mm), the UV curable resin 22 is spread so as to have a thickness of 80 μm. Next, using the ultraviolet irradiation device 20, from the plastic plate side, 30 seconds, 100 mW / cm
^The ultraviolet curable resin 22 is irradiated with ultraviolet rays of intensity ²
Is cured (b). Stamper 7 and UV curable resin 2
When the gap between the two is peeled off, the replica substrate 1 in which the grooves and pits of the stamper 7 are transferred is obtained (c).

On the information pattern surface of the replica substrate 1,
SiN enhance film 12 (thickness: 30 nm), TbFe
Co magnetic film 13 (thickness: 30 nm), AlN reflective film 14
(Thickness: 30 nm), SiN protective film 15 (thickness: 30 n
Substrate 3 in which the recording film 28 was formed on the replica substrate 1 was manufactured (d).

On the recording film of the substrate 3 produced as described above, an adhesive obtained by mixing the main component of the two-component curable silicone adhesive of Examples 9 and 10 in Table 1 and the curing agent was applied by spin coating. It was applied to form an adhesive layer 4 having a thickness of 30 μm (e). Further, this step was repeated to produce another substrate 3 having the adhesive layer 4 formed thereon.

Next, the substrate 3 is placed in the closed container 21 with the adhesive layer 4 inside, and the gap 35 between the substrates 3 is 5 m.
The pressure inside the closed container 21 is reduced to 1 Torr in order to create a reduced pressure atmosphere (f).

Thereafter, the adhesive layers of the two substrates 3 were brought into contact with each other, and a pressure of 0.4 kg / cm 2 was applied for 5 seconds to bond them (g). Finally, it was taken out from the container 21 to obtain an optical disc having two substrates 3 and an adhesive layer 2 (i).

Comparative Examples 1 and 2 In this Comparative Example, the adhesives of Comparative Examples 1 and 2 in Table 1 were used,
An optical disc was produced by the same optical disc manufacturing method as in Example 3.

Comparative Examples 3 and 4 In this Comparative Example, using the adhesives of Comparative Examples 3 and 4 in Table 1,
An optical disc was prepared by the same optical disc manufacturing method as in Example 6.

Comparative Examples 5 and 6 In this comparative example, an optical disk was produced by the same optical disk manufacturing method as in Example 8 using the adhesives of Comparative Example 5 of Table 1 and Comparative Example 6 of Table 2.

[0082]

[Table 2]

Comparative Example 7 In this comparative example, an optical disk was prepared by using the adhesive of Comparative Example 7 in Table 2 and by the same optical disk manufacturing method as in Example 10.

Comparative Example 8 In this comparative example, the hot melt adhesive of Comparative Example 8 in Table 3 was used, and

[0085]

[Table 3]

Two replica substrates having the recording film obtained in FIG. 6i-1 were prepared, and hot-melt adhesive was applied to the recording film surfaces of the two replica substrates with a hot-melt coater to a film thickness of 30 μm. applied to, in the alignment facing adhesive coated surface to prepare a disc of Comparative example 10 was laminated with a load of an optical disc and 20 kg / cm ² of Comparative example 9 was laminated with a load of 2 kg / cm ^2.

Comparative Example 9 In this comparative example, the one-component anaerobic curable adhesive of Comparative Example 9 in Table 3 was used, and the replica substrate 2 having the recording film obtained in FIG. One sheet was prepared, one recording liquid surface of one of the two replica substrates was spin-coated with a one-component anaerobic curable adhesive, and the two replica substrates were bonded together under a reduced pressure of 20 mTorr to form an optical disc.

Comparative Example 10 In this comparative example, the two-liquid non-mixing adhesive of Comparative Example 10 in Table 3 was used, and two replica substrates having the recording film obtained in FIG. 6i-1 of Example 3 were formed. Prepare and spin-coat one recording film surface of the two replica substrates with the two-liquid non-mixed adhesive agent A and the other replica substrate with the coating agent B, respectively, and apply two replica substrates at 20 mTorr. A bonded optical disc was prepared under reduced pressure.

(Effects of Each Example) As described above, Examples 1 to 10 and Comparative Examples 1 to 10 bonded by using various adhesives.
For the optical disc of No. 3, the vertical deflection acceleration corresponding to the occurrence state of uneven defects after bonding, the tilt angle corresponding to the deformed state of the disc, the amount of substrate displacement after leaving at 80 ° C./1 h,
Examine the presence or absence of substrate misalignment immediately after bonding (visual observation) and the presence or absence of defects such as irregularities and warpage on the disk surface after bonding (during manufacturing) and after heat treatment (during use and storage) (visual observation) did. The measurement results of Examples 1 to 10 are shown in (Table 4), and the measurement results of Comparative Examples 1 to 10 are shown in (Table 5).

The measurement of these characteristics was carried out as follows. Mechanical characteristics (vertical deflection acceleration and tilt angle)
Is an optical disc mechanical characteristic measuring device (laser wavelength: 780n
m, measurement rotation speed: 2400 rpm, measurement position: 300 m
In the case of an m disc, the measurement was performed with φ290 mm, and with a 130 mm disc, φ120 mm). The amount of deviation is 500 for a disk piece (film thickness: 30 μm, adhesion area: 6 cm ² ).
The amount of displacement when a shear load of g was applied was measured. As for the displacement of the substrate immediately after bonding by visual observation, the presence or absence of the displacement of the substrate when supporting the center or the outer periphery of the substrate was determined. The presence or absence of defects by visual observation was determined by a device (shadow graph) that applies light to the object to be irradiated and magnifies and projects the reflected light. For example, when the surface of the optical disc is uneven or warped, the light and darkness of the light and the size of the projection are differently projected on the projection object.

[0091]

[Table 4]

[0092]

[Table 5]

From the results of Tables 4 and 5, it was found that the disks of Examples 1 to 10 satisfied the vertical deflection acceleration (target: ≤2G), the tilt angle (≤5mrad) and the shift amount (≤20µm). Furthermore, no substrate displacement immediately after bonding and no defects during manufacturing or heating were observed. On the other hand, in Comparative Examples 1, 3, and 7, the vertical shake acceleration did not satisfy the target, and defects were found during manufacturing and due to heating. In Comparative Examples 2 and 4, the target of the tilt angle was not satisfied, and the displacement of the substrate immediately after bonding and the occurrence of defects due to heating were observed. In Comparative Example 5, it was found that the vertical deviation acceleration target was not satisfied and the substrate was misaligned immediately after bonding, and defects were generated during manufacturing and due to heating. In Comparative Example 6, the inclination angle and the amount of deviation due to heating did not meet the target, and the occurrence of defects due to substrate deviation and heating immediately after bonding was observed. In Comparative Example 8, none of the targets was met, and defects were found during production and due to heating. In Comparative Example 10, it was found that the targets of the vertical deflection acceleration and the tilt angle were not satisfied, the substrate was displaced immediately after the bonding, and defects were generated due to heating.

From the above results, there is a correlation between the viscosity of the adhesive and the displacement of the substrate immediately after the bonding, the hardness after curing of the adhesive, the vertical deflection acceleration, the tilt angle, and the amount of displacement of the substrate. The disc in which the substrate is displaced immediately after the bonding is generated when the bonding is performed with an adhesive having a low viscosity of the adhesive less than 10 poise. On the other hand, at 700 poises or more, the vertical deflection acceleration becomes large due to the uneven application surface of the adhesive. Further, when the tilt angle and the amount of displacement of the substrate do not satisfy the target, the hardness after curing the adhesive is 20 or less, and when the tilt deflection and the amount of displacement of the substrate do not satisfy the target of the vertical deflection acceleration, the hardness after curing the adhesive is 80 or more. I knew that.

Further, with respect to the optical discs of Examples 1 to 10, recording was performed at a disc rotation speed of 2400 rpm by a recording / reproducing device (optical head using a laser of 680 nm as a light source and a numerical aperture of 0.55 and a focusing lens of about 2 μm). As a result of the reproduction, no recording / reproduction failure occurred.

From the above, the optical disk bonded with the adhesive of the present invention is excellent in flatness and highly accurate with little unevenness or deformation even in a heating atmosphere.

[0097]

[Table 6]

[0098]

According to the present invention, it is possible to realize an optical disc having high precision and high reliability by reducing high-speed access, deformation due to high-speed rotation, deformation and peeling due to aging during storage, and a manufacturing method thereof. be able to.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an optical disc of the present invention.

FIG. 2 is a sectional view of an optical disc of the present invention.

FIG. 3 is a manufacturing process diagram of the stamper of the present invention.

FIG. 4 is a manufacturing process diagram of the stamper of the present invention.

FIG. 5 is a process drawing of an optical disc manufacturing method of the present invention.

FIG. 6 is a process drawing of an optical disc manufacturing method of the present invention.

FIG. 7 is a process drawing of an optical disc manufacturing method of the present invention.

FIG. 8 is a process drawing of an optical disc manufacturing method of the present invention.

FIG. 9 is a process drawing of an optical disc manufacturing method of the present invention.

FIG. 10 is a process drawing of an optical disc manufacturing method of the present invention.

FIG. 11 is a process drawing of an optical disc manufacturing method of the present invention.

FIG. 12 is a process drawing of an optical disc manufacturing method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Replica substrate, 2 ... Recording metal film, 3 ... Substrate 4 ... Adhesive layer, 5 ... Ni film, 6 ... Ni electroformed film, 7 ... Stamper, 8 ... Mold, 9 ... Mold internal gap, 10 ... Polycarbonate resin, 12 ... SiN enhance film, 13 ... TbF
eCo magnetic film, 14 ... AlN reflective film, 15 ... SiN protective film, 16 photoresist film, 17 ... Glass disk, 18 ...
Decompression, 20 ... UV irradiation device, 21 ... Closed container, 22 ...
UV curable resin, 23 ... Plastic plate, 24 ... Replica substrate, 25 ... GeSbTe recording film, 26 ... SbBi
Reflective film, 27 ... SiN protective film, 34 ... Hole at center of optical disc, 35 ... Substrate gap,

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuo Tajima 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Ltd. Within the Institute of Industrial Science, Hitachi, Ltd. Issue Hitachi Maxell Co., Ltd. (72) Inventor Toshiaki Yasui 1-88, Tora, Ibaraki, Osaka Prefecture

Claims (8)

[Claims] 1. A pair of opposing substrates and an adhesive layer, at least one of the substrates having a recording film, the adhesive layer comprising:
The optical disc arranged in the gap between the pair of opposed substrates, wherein the adhesive layer contains a two-component curable silicone resin. 2. The optical disc according to claim 1, wherein the adhesive layer has a viscosity of 10 to 700 poises. 3. The optical disc according to claim 1, wherein the adhesive layer has a hardness of 20 to 80 (JIS A). 4. An adhesive application step of applying an adhesive to two transparent substrates having a recording layer formed on at least one side to form an adhesive layer, and the above two sheets so that the adhesive layer is on the inner side. A method of manufacturing an optical disk, comprising a step of facing a transparent substrate and applying pressure to bond the transparent substrate, wherein the adhesive contains a two-component curable silicone adhesive. 5. The optical disc manufacturing method according to claim 4, wherein the adhesive has a viscosity of 10 to 700 poises. 6. The hardness according to claim 4, wherein the hardness of the adhesive after curing is 20 to 80 (JIS.
A method for manufacturing an optical disk, characterized in that the method is A). 7. The optical disk manufacturing method according to claim 4, wherein the pressure is 0.4 to 0.8 kg / cm 2. 8. The optical disc manufacturing method according to claim 4, wherein the bonding step is performed in a reduced pressure atmosphere, and the reduced pressure atmosphere is 1 to 20 Torr.