JPH08102084A - Information recording medium and its manufacture - Google Patents

Abstract

PURPOSE: To manufacture the high density and high accuracy recording medium through reducing the dullness or unsharpness of the periphery of each of the record pits of the medium and to provide the manufacture of the medium. CONSTITUTION: This medium is provided with a multilayer film 1B12 which consists of at least two layers and is formed by alternately laminating high refractive index layers 1B1 and low refractive index layers 1B2 one by one in that order repeatedly on a transparent substrate 1A, and a resin film IC laminated on this multilayer 1B12 . At least one refractive index layer of the high refractive index layers 1B1 and low refractive index layers 1B2 has hole- like record pits 1P which are formed by an etching method after forming the multilayer film 1B12 . The incident laser beam on each of the pits 1P is reflected by a reflection layer provided at the bottom of the inside of the pit 1P and a phase difference between this reflected laser beam from the pit 1P and another reflected laser beam from an unrecorded part is generated to reduce the quantity of the reflected light by the interference. Thus, this medium enables reproduction by the push-pull method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium and a manufacturing method thereof, and more particularly to an information recording medium capable of writing and reading information by a reproducing energy beam such as a laser beam or an electron beam and a manufacturing method thereof. Is.

[0002]

2. Description of the Related Art As a method of forming unevenness information (recording pits) on a substrate for an optical disk, a method of forming unevenness information on a plastic substrate using an injection molding method and an ultraviolet curable resin are used. A photopolymer method (2P method) for forming uneven information on a substrate is known.

A conventional method for manufacturing an optical disk will be described below.

(A). Resist master process This process is a process for making a master as a base for manufacturing an injection molding stamper. First, after thoroughly washing the substrate, in order to prevent peeling of the resist layer in the next step, the silane coupling agent is vaporized and adsorbed on the glass substrate,
Apply an adhesive agent treatment. After drying, a photoresist is uniformly applied by a spin coating method, and then a recording pit is exposed by a laser cutting method. Next, a developing solution is dropped while rotating the resist disk to remove the latent image portion and develop to obtain a master disk.

(B). Electroforming step This step is a step of producing a stamper from a master.
First, in order to add conductivity to the resist master, a Ni thin film having a thickness of about 100 nm is formed by sputtering Ni to form a conductive film to be an electrode for electroforming.

Electroforming is performed in a low-stress nickel sulfamate bath using the Ni thin film of the resist master as a cathode and depolarized nickel with high dissolution efficiency as an anode.

The Ni plate is peeled off together with the Ni thin film from the resist master, and the Ni plate from which the resist on the surface has been removed is the master plate. When the back plate is directly polished and used for injection molding, it becomes a master stamper, but normally the surface layer is oxidized. By repeating the processing and electroforming, a master board is prepared as a mother board, a mother board is made as a stamper, and about 25 stampers are made from one master board.

(C). Replication step This step is a step of manufacturing a disk substrate with recording pits from a stamper. First, after sufficiently drying the pellets that are the raw material of the resin, attach the stamper to the movable mold of the injection molding machine, inject the resin in the heating and melting state into the hollow part with the fixed mold finished to the mirror surface, compress, After holding the pressure, the disc substrate is forcedly cooled and the formed disc substrate is taken out from the mold.

(D). Forming process of reflective film and protective film Aluminum (Al) on the formed disk substrate
These are the film formation of the reflective film, the application of the UV curable resin, and the curing process. First, Al is sputtered on the disk substrate.
A reflective film is formed with a thickness of around 80 [nm]. Next, an ultraviolet curable resin is applied by a spin coating method and then cured by irradiation with ultraviolet rays.

On the other hand, the optical disk is different from the above manufacturing method.
High-density recording of information and high accuracy of recorded data are required. However, since the original pit information is transferred at least twice (plating and injection molding) by using the above-described conventional manufacturing method, the transfer accuracy is higher than that by the exposure method using the mask used in semiconductor manufacturing. 1 to 2 digits lower. For this reason, when the recording pit is reproduced by the reproduction beam, sagging or blurring occurs in the peripheral portion of the recording pit due to transfer failure, which causes intersymbol interference or crosstalk to deteriorate the jitter value. Had.

In order to solve such a problem, for example, in Japanese Unexamined Patent Publication (Kokai) No. 4-146539, high density, high accuracy is obtained by using a dry etching method on a flat one-layer reflective material provided on a substantially flat resin substrate. An optical disc having information pits has been proposed.

More specifically, the recording pit portion is formed of a reflective material having a high reflectance, and the unrecorded portion is made transparent by removing the reflective material, and the recording pit portion has a high reflectance. The medium structure is made of a low non-reflective material and the unrecorded portion is formed of a reflective material having a high reflectance, the unrecorded portion is formed of a reflective material having a high reflectance, and the recording pit portion is made of a reflective material. Are removed to form a light-transmitting hole-like medium.

[0013]

However, the optical disk disclosed in the above-mentioned Japanese Patent Laid-Open No. 4-146539 has the following problems in the medium structure and manufacturing process.

The first problem is C / N with good signal quality.
Sufficient reflectance and reflectance difference are required to obtain the ratio,
This means that the usable reflective film is limited because there is only one reflective film. In the case of a normal density compact disc currently on the market, its reflectance is 780 [n
m], the unrecorded area is 70% or more and the on-pit state of the recorded area is 28% or less. Therefore, the reflectance difference is 42%, and at the same time, the C / N is 60 [d
B] or more. Elements having a reflectance of 70% or more for 780 [nm] laser light are Rh, Cu, Ag, Au, A
It is only l and In, and other elements cannot be used as the reflective film.

The second problem is that in the reproducing system, the optical disk disclosed in Japanese Patent Laid-Open No. 4-14639 has a laser beam which is transmitted through an unrecorded portion due to the above-mentioned medium structure, so that the focus servo and the track can be performed. Servo is not applied. Further, in the above-mentioned medium structure, since there is almost no phase difference between the reflected light of the recording pit and the reflected light of the unrecorded portion, the push-pull method of the reproducing method which is generally used cannot be used, and the heterodyne method is used. The three-beam method must be used.

A third problem is that although the manufacturing process of the optical disk having the medium structure is shown, the manufacturing process of the optical disk having the medium structure is not shown (not disclosed).

According to the conventional method of manufacturing an optical disk master, the intensity distribution of the exposure beam has a Gaussian distribution, so that the latent image formed on the photoresist film by exposure also has a substantially Gaussian distribution. Since the latent image has a substantially Gaussian distribution including a halftone portion in the cross section of the pit formed by the development, as shown in FIG. 18, the shape changes from the shape of the symbol a to the shape of the symbol e as the development progresses. Therefore, for example, as shown in FIG. 19, the pit P appears as a sag or blur in a portion equal to the spread of the tail of the Gaussian distribution. This FIG.
In FIG. 5, reference numeral 51 indicates a transparent substrate, reference numeral 52 indicates a metal reflection film, reference numeral 53 indicates a resin film, and reference numeral 54 indicates a sag or blur portion.

[0018]

It is an object of the present invention to improve the disadvantages of the above-mentioned conventional example, particularly to reduce the sagging and blurring around the recording pits due to transfer defects, to achieve high density and high accuracy, and at the same time, to realize focus servo and track servo. It is an object of the present invention to provide an information recording medium that can be stably applied and a method for manufacturing the same.

[0019]

According to the present invention, in claim 1 (or 2) thereof, a transparent substrate and a high refractive index layer and a low refractive index layer (or a low refractive index layer and a low refractive index layer coated on the transparent substrate). A high refractive index layer and a low refractive index layer (or a low refractive index layer), comprising a multilayer film of two or more layers repeated in the order of a high refractive index layer and a resin film laminated on the multilayer film. And high refractive index layer), at least one refractive index layer has a hole-shaped recording pit.

According to the present invention, in addition to the structure of claim 1 (or 2) described in claim 3 (or 4), at least the reflective layer is coated on the multilayer film. I am collecting.

In the present invention, the film thickness of each of the high refractive index layer and the low refractive index layer is defined as λ.
/ 4 n (λ is the wavelength of laser light, n is the refractive index of the refractive index layer)
And the configuration is adopted.

Further, in the present invention, in claim 6, the high refractive index layer is formed of a hydrogen-containing alloy of amorphous Si, and the hydrogen-containing alloy of amorphous Si is expressed by a general formula of an average composition in a film thickness direction. "Si _1-X H _X "
When expressed by, x is atomic percentage of “28/47 ≦ x ≦
The configuration is such that the one in the range of 28/29 ”is used. In this case, the refractive index is 4.0≤nx≤4.5.

Further, in the present invention, in claim 7, the high refractive index layer is formed of a hydrogen-containing alloy of microcrystallized Si, and the hydrogen-containing alloy of microcrystallized Si is averaged in the film thickness direction. When represented by the general formula “Si _1-X H _X ”, the composition is such that x is an atomic percentage in the range of “28/47 ≦ x ≦ 28/37”. In this case, the refractive index is 3.3 ≦ nx ≦ 3.5.

Further, in the present invention, in claim 8, the high refractive index layer is formed of an amorphous Si C hydrogen-containing alloy, and the amorphous Si C hydrogen-containing alloy has an average composition in the film thickness direction. General formula “(Si C)
_1-X H _X ", x is an atomic percentage of" 40
/ 49 ≦ x ≦ 40/41 ”is used. In this case, the refractive index is 3.1 ≤ nx ≤ 4.1
Becomes

In the present invention, the high refractive index layer is formed of a hydrogen-containing alloy of amorphous SiGe and the hydrogen-containing alloy of amorphous SiGe has an average composition in the film thickness direction. General formula "(Si
Ge) _1-X H _X ", the composition is such that x is an atomic percentage in the range of" 503/598 ≤ x ≤ 503/518 ". In this case, the refractive index is 3.2 ≦ nx ≦ 3.8.

Further, in the present invention, in claim 10, the high refractive index layer is formed of a nitride of amorphous Si, and the nitride of the amorphous Si is expressed by a general formula "Si of the average composition in the film thickness direction. _1-X N _X ", the composition is such that x is an atomic percentage within the range of" 0≤x≤4 / 7 ". in this case,
The refractive index is 2.0≤nx≤3.82.

Further, in the present invention, in claim 11, the high refractive index layer is formed of an oxide of amorphous Si, and the oxide of amorphous Si is expressed by a general formula "Si" having an average composition in the film thickness direction. _1-X O _X ", the composition is such that x is an atomic percentage in the range of" 0≤x≤2 / 3 ". in this case,
The refractive index is 1.46 ≦ nx ≦ 3.82.

According to the twelfth aspect of the present invention, in the high refractive index layer, the high refractive index medium has a low refractive index medium having a refractive index n <1.5, and a high refractive index medium having a refractive index 1.5 ≦ n <3.0. And a medium of the high refractive index layer having a refractive index n ≧ 3.0, having a uniform intermediate refractive index formed by mixing at least two kinds of media having different refractive indexes. I am collecting.

According to the thirteenth aspect of the present invention, the first metal reflective film, the low refractive index layer and the second metal film are provided on the transparent substrate.
The metal reflection film and the resin film are sequentially coated. And the first
The structure is such that a hole-shaped recording pit is formed in the metal reflection film.

According to the fourteenth aspect of the present invention, on the transparent substrate, the first metal reflection film, the high refractive index layer and the second metal film are provided.
The metal reflection film and the resin film are sequentially coated. And the first
The structure is such that a hole-shaped recording pit is formed in the metal reflection film.

According to the fifteenth aspect of the present invention, as a method for manufacturing an information recording medium, a high refractive index layer and a low refractive index layer or a low refractive index layer and a high refractive index layer are formed on a transparent substrate in this order. A repeating multilayer film consisting of at least one layer is formed, and then a photoresist layer is laminated, and then light corresponding to writing information is irradiated to expose the photoresist layer in the light irradiation region, and thereafter, The exposed photoresist layer is developed to remove the photoresist layer in the light irradiation region and expose the high refractive index layer or the low refractive index layer, and then etching is performed to increase the height of the removed region of the photoresist layer. The configuration is such that a recess is formed in at least one of the refractive index layer and the low refractive index layer.

According to the sixteenth aspect of the present invention, the etching method in the method of manufacturing the information recording medium is an ion milling method using argon plasma or the like.

Further, in the present invention, in the seventeenth aspect thereof, the etching method in the method of manufacturing the information recording medium is a reactive ion etching method using carbon tetrachloride.

This is intended to achieve the above-mentioned object.

[0035]

[Operation] First, an explanation will be given of an example of the optical action of the constitution common to each claim relating to the information recording medium of the present invention, that is, the repeating multilayer film of the high refractive index layer and the low refractive index layer.

In the present invention, a high refractive index layer and a low refractive index layer are laminated in this order on a transparent substrate, and a repeating multilayer film having a film thickness of λ / 4 or close thereto or a low refractive index layer and a high refractive index layer in this order. It is used as a reflecting mirror by laminating at least one layer of a λ / 4 repeating multi-layered film.

When the λ / 4 films having a high refractive index and the low refractive index are respectively set to H and L, as an example of a multilayer film reflecting mirror,
"Air _{(n 0) -H (LH ···} LH) - Glass (n)", for short, "air -H (LH) ^q - glass" is intended configuration in. Then, "n ₁ = n ₃ = ... =
Given that “n _{2q + 1} = n _H ”, “n ₂ = n ₄ = ... = n _2q = n _L ”, the energy reflectance R with respect to the center wavelength is calculated from the method of determining the boundary condition of a general electromagnetic field. R = - a _{[(n 0 n 3 n L} 2q n H 2 (q + 1)) / (n 0 n 3 n l 2q + n H 2 (q + 1))] 2 × 100 ...... <1> . When the reflectance in the case of q = 1, 2 is calculated using this equation <1>, R = 68 [%] and q = 2 when q = 1.
Then R = 93 [%] (where n ₀ = 1 and n ₃ =
Calculated as 1.52, n _L = 1.38, n _H = 2.35).

Next, the optical function of forming the hole-shaped recording pits will be described. A pit-shaped hole is formed in a repeating multilayer film of a high refractive index layer and a low refractive index layer by dry etching to form at least one layer. By removing the refractive index layer, the low refractive index layer, or both layers, the optical interference conditions described above are broken, and the laser light incident on the pit portion is transmitted.
Therefore, when the laser light is positioned on the recording pit, the reflected light is reduced by the amount of transmitted light, and the detection system can read it.

The reflective layer optically functions as follows. That is, when a recording medium having a reflective layer composed of a metal or high-refractive index layer and a low-refractive layer repeating multilayer film coated on the repeating multilayer film after forming hole-shaped recording pits is used, a pit portion is formed. The laser light incident on is reflected by the reflection layer at the lower part of the recording pit, a phase difference occurs with respect to the laser light reflected at the unrecorded part, and the amount of reflected light decreases due to interference. Therefore, reproduction by the conventional push-pull method becomes possible.

Further, in the manufacturing method according to claims 15 to 17 of the present invention, the recording pits are formed by exposing and developing the photoresist in the conventional method for producing a master for an optical disk. By using the positive type photoresist used to form the recording pits as a mask for dry etching by reversing the exposure state in a substantially Gaussian shape, recording pits smaller than the exposure beam diameter can be formed, Higher density is possible.

In the exposure step, it is possible to manufacture the information recording media one by one by the direct laser cutting method. First, a high-density and high-precision photomask is manufactured by using the above dry etching method. It is also possible to mass-produce by the contact exposure method.

Since the information recording medium according to the present invention can be manufactured by using a dielectric material having a high refractive index and a low refractive index, it has excellent reliability for long-term data storage.

Further, in the information recording medium of the present invention, the recording pit has a medium structure for transmitting the laser beam, so that an optical phase difference exists between the reflection surface of the unrecorded portion and the transmission surface of the recording portion. Therefore, it is superior to the super-resolution optical system as a reproducing medium.

[0044]

[First Embodiment] A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows an information recording medium 1 in this embodiment.
FIG. Of these, FIG.
It is an expanded partial sectional view of the A section in (a).

In FIG. 1 (a), this embodiment is a two-layer structure in which a transparent substrate 1A and a high refractive index layer 1B ₁ and a low refractive index layer 1B ₂ coated on the transparent substrate 1A are repeated in this order. or the multilayer film 1B _12, and a resin film 1C stacked on the multilayer film 1B _12. And the high refractive index layer 1
At least _one refractive index layer of B ₁ and the low refractive index layer 1B ₂ has a hole-shaped recording pid 1P.

The high refractive index layer 1B ₁ and the low refractive index layer 1B ₂ are
The charts (1) to (1) shown in FIGS. 2 to 3 respectively.
It is coated with any of the materials, configurations, and film thicknesses shown up to 2). The recording pit 1P is formed by etching after forming the above-mentioned multilayer film 1B ₁₂ . Reference symbol P indicates a pit portion, and reference symbol M indicates a mirror portion.

2 to 3 show the calculation results of the medium reflectance when the material of the multilayer film 1B ₁₂ is variously changed and when the number of times of repeating the layers is changed. That is, the number of repetitions of the layer (HL) in which the high refractive index layer 1B ₁ is H and the low refractive index layer 1B ₂ is L, and the low refractive index layer L and the high refractive index layer H are laminated on the transparent substrate 1A described above is If q, wavelength 6
The right column shows the optical calculation results of the medium reflectance with respect to a laser beam of 80 [nm]. As a result, the reflectance is 70% when q = 1.
It turned out to be the above.

In the first embodiment, the laser light incident on each of the recording pids 1P is reflected by the reflection layer at the bottom of the recording pid 1P, and is positioned with respect to the laser light reflected by the mirror M. A phase difference occurs, which causes interference and reduces the amount of reflected light. Therefore, reproduction by the push-pull method is possible.

Since the first embodiment can be constructed by using a dielectric material having a high refractive index and a low refractive index, it is excellent in long-term data storage. Further, in the information recording medium in the first embodiment, each recording pid 1P has a medium structure that allows a laser beam to pass therethrough, so that the optical phase difference between the reflection surface of the unrecorded portion and the transmission surface of the recording portion is increased. Since it does not exist, it is superior to the super-resolution optical system as a reproducing medium.

[0051]

[Second Embodiment] FIGS. 4 to 6 show a second embodiment. Here, the same reference numerals are used for the same constituent members as those in the first embodiment shown in FIG.

Information recording medium 2 in the second embodiment
Includes a transparent substrate 2A, at least two or more layers of the multilayer film 2B ₂₁ was repeated on the transparent substrate 2A in the order of the coating, low-refractive index layer 2B ₂ and the high-refractive index layer 2B _1, the multilayer film 2B ₂₁ And a resin film 2C laminated on top. At least one refractive index layer of the low refractive index layer 2B ₂ and the high refractive index layer 2B ₁ is provided with a hole-shaped recording pid 2P.

The high refractive index layer 2B ₁ and the low refractive index layer 2B ₂ are
(13) to (2) in the tables disclosed in FIGS. 5 to 6, respectively.
It is coated with any of the materials, configurations, and film thicknesses shown up to 4). The recording pit 2P is formed by etching after forming the above-mentioned multilayer film 2B ₂₁ .

FIGS. 5 to 6 show the calculation results of the medium reflectivity when the material of the multilayer film 2B ₁₂ is variously changed and when the number of times of repeating the layers is changed. That is, the number of repetitions of the layer (HL) in which the high refractive index layer 2B ₁ is H and the low refractive index layer 2B ₂ is L, and the low refractive index layer L and the high refractive index layer H are laminated on the transparent substrate 2A described above is When q, the wavelength is 680
The right column shows optical calculation results of medium reflectance with respect to laser light of [nm]. As a result, it was found that the reflectance was 70% or more when q = 2. For other effects,
It is equivalent to the first embodiment described above.

[0055]

[Third Embodiment] FIGS. 7 to 8 show a third embodiment. First, as shown in FIG. 7, the information recording medium 3 in the third embodiment includes a transparent substrate 3A, and a high refractive index layer 3B ₁ and a low refractive index layer 3B ₂ sequentially coated on the transparent substrate 3A.
And a reflective film 3C laminated on the low refractive index layer 3B _2.
And a resin film 3D laminated on the reflective film 3C.

Recording pits 3P are formed on the high refractive index layer 3B ₁ by etching. Low refractive index layer 3B
₂ is laminated on the high refractive index layer 3B ₁ after forming the recording pit 3P.

The low-refractive index layer 3B ₂ is also filled in the recording pits 3P of the high-refractive index layer 3B ₁ . Therefore, the low-refractive-index layer 3B ₂ has the recording pit
The P portion forms a concave portion, and at the same time, the reflective layer laminated thereon also has a concave portion formed in the recording pit 3P portion. The other structure is the same as that of the embodiment shown in FIG.

In FIG. 8, in the medium structure shown in FIG. 7, the transparent substrate 3A is made of polycarbonate, the high refractive index layer 3B ₁ is Si (45 nm), and the low refractive index layer 3B ₂ is SiO _2.
(-), The reflectance of the mirror portion M and the pit portion P when the reflection layer 3C is Al (98 nm), and the phase difference between the reflected light of the mirror portion M and the reflected light of the pit portion P depend on the SiO ₂ film thickness Sex
The result of optical calculation for a laser beam having a wavelength of 680 [nm] is shown.

According to this, the SiO ₂ film thickness is 105 [n
m], the absolute value of the phase difference is 180 [deg], the reflectance of the pit P is 86%, and the reflectance of the mirror M is 78.
It became [%], and it became clear that the medium is suitable for a reproducing optical system using the push-pull method. Also, SiO
_{2 When the} film thickness is around 220 [nm], the absolute value of the phase difference is 180
[Deg], the reflectance of the pit portion P is 85%, the reflectance of the mirror portion M is 8%, and the medium configuration is such that the reflectance of the mirror portion M is higher than the reflectance of the pit portion P. so,
It became clear that the medium is suitable for high density.

[0060] Here, in the third embodiment, adapted to deposit a low-refractive index layer 3B ₂ on the high refractive index layer 3B ₁ after forming the recording pits 3P in the high refractive index layer 3B ₁ was, but conversely the high refractive index layer 3B ₁ interchanged the low refractive index layer 3B _2, a high refractive index is formed over the low-refractive index layer 3B ₂ after forming the recording pits 3P in the low refractive index layer 3B ₂ It may be configured to deposit the layer 3B ₁ .

[0061]

[Fourth Embodiment] FIGS. 9 to 10 show a fourth embodiment. As shown in FIG. 9, the information recording medium 4 in the fourth embodiment includes a transparent substrate 4A, a high refractive index layer 4B ₁ and a low refractive index layer 4B ₂ sequentially coated on the transparent substrate 4A, and The reflective layer 4C is laminated on the low refractive index layer 4B ₂ , and the resin film 4D is laminated on the reflective film 4C. Therefore, the low refractive index layer 4B ₂ is also filled in the recording pit 4P of the high refractive index layer 4B ₁ .

Here, in the fourth embodiment, after the recording pit 4P is formed in the high refractive index layer 4B ₁ , the low refractive index layer 4B ₂ is formed and leveled, and then the reflective layer 4C and the resin are formed. The feature is that the layers 4D are sequentially laminated to form a medium. Therefore, the reflection layer 4C and the resin layer 4D are formed to have uniform thickness without unevenness. The other structure is the same as that of the embodiment shown in FIG.

In FIG. 10, in the above-described medium structure of FIG. 9, the transparent substrate 4A is made of polycarbonate and the high refractive index layer 4B.
₁ for Si (45 nm) and low refractive index layer 4B ₂ for SiO ₂ (-) +
SiO ₂ (45 nm) and the reflectance of the mirror portion M and the pit portion P when the reflection layer 4C is Al (98 nm) and the phase difference between the reflected light of the mirror portion M and the reflected light of the pit portion P SiO ₂ The result of optical calculation of the film thickness dependency with respect to a laser beam having a wavelength of 680 nm is shown.

As a result, the absolute value of the phase difference is 180 [deg], the reflectance of the pit P is 87 [%], and the reflectance of the mirror M is 70 [%] when the SiO ₂ film thickness is around 50 [nm]. ]
Therefore, it was found that the medium is suitable for a reproducing optical system using the push-pull method.

Further, in the vicinity of the SiO ₂ film thickness of 220 [nm], the absolute value of the phase difference is 180 [deg], the reflectance of the pit P is 85 [%], and the reflectance of the mirror M is 8 [%]. Therefore, it has been clarified that the medium configuration is such that the reflectance of the mirror portion M is higher than that of the pit portion P, and the medium is suitable for high density.

[0066]

[Fifth Embodiment] FIGS. 11 to 12 show a fifth embodiment.

Information recording medium 5 in the fifth embodiment
, First, as shown in FIG. 11, a transparent substrate 5A, this is sequentially coated on a transparent substrate 5A the high refractive index layer 5B ₁ and the low refractive index layer 5B _2, on the low-refractive index layer 5B ₂ And a resin film 5D laminated on the reflection layer 5C. In the fifth embodiment, the high refractive index layer 5B ₁ and the low refractive index layer 5B ₂ are commonly used.
The feature is that the hole portion of the recording pit 5P is formed.

Therefore, in the hole portion of the recording pit 5P,
The reflection layer 5C described above is filled, and the resin film 5D described above is also filled in the hole portion of the recording pit 5P while being laminated on the reflection layer 5C.

In FIG. 12, in the above-mentioned medium structure of FIG. 11, the transparent substrate 5A is made of polycarbonate and the high refractive index layer 5 is formed.
B ₁ is Si (45 nm) and the low refractive index layer 5B ₂ is SiO ₂
(-), The reflectance of the mirror portion M and the pit portion P when the reflection layer 5C is Al (98 nm), and the SiO ₂ film thickness of the phase difference between the reflected light of the mirror portion M and the reflected light of the pit portion P The result of the optical calculation of the dependence on the laser light of wavelength 680 [nm] is shown. As a result, the absolute value of the phase difference is 180 [deg], the reflectance of the pit P is 86 [%], and the reflectance of the mirror M is 5 [%] near the SiO ₂ film thickness of 110 [nm]. It has been clarified that a medium having a higher reflectance in the portion M than the reflectance in the pit portion P is suitable for high density.

[0070]

Other Embodiments FIGS. 13 to 15 show other embodiments of the present invention.

The respective embodiments shown in FIGS. 13 to 15 are
It is characterized by having two metal reflection layers and forming recording pits in the first metal reflection layer.

First, referring to FIG. 13, the information recording medium 6
Is the first metal reflective layer 6 sequentially coated on the transparent substrate 6A.
B, the low refractive index layer 6C, the second metal reflective layer 6D laminated on the low refractive index layer 6C, and the second metal reflective layer 6D
And a resin film 6E laminated on top.

Then, the information recording medium 6 shown in FIG.
In the second aspect, the medium is constituted by forming the recording pits 6P on the first metal reflection layer 6B and then sequentially laminating the low refractive index layer 6C, the second metal reflection layer 6D, and the resin layer 6E. The other structure is the same as that of the embodiment shown in FIG.

Further, in FIG. 14, the information recording medium 7
Is the first metal reflective layer 7 sequentially coated on the transparent substrate 7A.
B, the low-refractive index layer 7C, the second metal reflective layer 7D laminated on the low-refractive index layer 7C, and the second metal reflective layer 7D
And a resin film 7E laminated thereon.

Then, the information recording medium 7 shown in FIG.
In the above, after forming the recording pits 7P in the first metal reflection layer 7B, the low refractive index layer 7C is formed and leveled, and then the second metal reflection layer 7D and the resin layer 7E are sequentially laminated. It is characterized by the fact that it is configured as a medium. The other structure is the same as that of the embodiment shown in FIG.

Further, in FIG. 15, the information recording medium 8
Is the first metal reflective layer 8 sequentially coated on the transparent substrate 8A.
B, high refractive index layer 8C, second metal reflective layer 8D laminated on this high refractive index layer 8C, and this second metal reflective layer 8D
And a resin film 8E laminated thereon.

Then, the information recording medium 8 shown in FIG.
In the second embodiment, the medium is configured by forming the recording pits 8P on the first metal reflection layer 8B and then sequentially stacking the high refractive index layer 8C, the second metal reflection layer 8D and the resin layer 8E. The other structure is the same as that of the embodiment shown in FIG.

FIG. 16 shows the reflectance of the pit portion P and the mirror portion M, and the reflected light of the pit portion P and the mirror portion M in the other embodiment described above, that is, in the medium structure shown in FIGS. The optical calculation results of the phase difference of the reflected light obtained for the laser light having a wavelength of 680 [nm] are shown.

From the result of the optical calculation, it was found that the information recording media 6 to 8 suitable for the reproducing optical system using the push-pull system can be obtained even if the medium structure having the two metal reflection layers is used. .

Here, in the first to fourth embodiments, the film thickness of each of the high refractive index layer and the low refractive index layer constituting the multilayer film is λ / 4 n (λ is the wavelength of laser light, n Is a refractive index of the refractive index layer) or a value close to this, it is possible to obtain one that functions more effectively as a reflecting mirror.

Next, an example of a method for manufacturing the information recording medium in each of the above embodiments, particularly a method for forming recording pits is shown in FIG.
It will be described based on.

[First Step] This step is a step of forming a high refractive index layer and a low refractive index layer. In this step, on a transparent substrate 1A-8A, the multilayer film 1B ₁₂ made of a high refractive index layer and a low refractive index layer for forming a recording pit 1P～8P, 2B
₂₁ or a high refractive index layer 3B ₁ , 4B ₁ , 5B
Only ₁ is deposited, or the metal reflection layers 6B, 7B, 8B are deposited by sputtering or vapor deposition.

[Second Step] This step is a resist coating step by a spin coating method. That is, the disk on which the first step has been completed is subjected to an adsorption treatment of a surfactant or the like, and then a photoresist is applied using a spin coating method. Immediately after the application of the photoresist, prebaking is performed in an oven at 90 ° C. for 30 minutes.

[Third Step] This step is an exposure step using light, an electron beam or the like. That is, the recording pits are exposed by the contact exposure method or the direct cutting method on the disk which has completed the second step.

[Fourth Step] This step is a developing step using an alkaline aqueous solution. That is, the disk which has been exposed in the third step is developed with an alkaline aqueous solution.

[Fifth Step] This step is a reactive etching step using plasma. That is, RIE or EC
A pit portion is formed in the layer formed in the first step by plasma etching of R or the like. As the etching gas,
CF ₄ , CF ₄ / O ₂ , CCl ₄ / He, CCl ₂ F ₂
/ N ₂ , CCl ₄ / SF ₆ , CBrF ₃ / Cl ₂ , Cl
₂ / Ar, CBrF ₃ , Sicl ₄ , CCl ₂ F ₄ / O
₂ , SiCl ₄ / Cl ₂ , CF ₄ / H ₂ , CHF ₃ , C
HF ₃ / O ₂ , CHF ₃ / CO ₂ , CHF ₃ / C
₂ F ₆ , CCl ₄ / He, CCl ₄ / BCl ₃ / O ₂ ,
BCl ₃ / Cl ₂ , BCl ₃ / CCl ₃ F / He, CC
l ₄ / O ₂ , CF ₄ / O ₂ , SF ₆ / Cl ₂ , Cl ₂ /
H ₂ or the like is used.

[Sixth to Seventh Steps] This step is a step of coating the resin layer and curing the ultraviolet rays. That is, the resin layers 1C and 2C are directly formed on the disk on which the recording pits 1P to 8P have been formed by the above-mentioned fifth step and then cured by applying an ultraviolet curable resin (step 6A), or
Alternatively, after the remaining photoresist is removed by ashing with O ₂ plasma or the like (step 6B), a high refractive index layer, a low refractive index layer, or a reflective layer is formed according to the medium structure. After that, the resin layers 3D to 5D and 6E to 8E are formed (seventh step). As a result, in each embodiment, a predetermined information recording medium can be obtained.

Next, the operation of the main constituent members in each of the above embodiments will be described.

First, the optical function of the repeating multilayer films 1B ₁₂ and 2B ₂₁ of the high refractive index layer and the low refractive index layer will be described. Each film thickness of the high refractive index layer and the low refractive index layer is λ on the transparent substrate. Repeated multi-layer film 1 with a film thickness of / 4 or near 1
B ₁₂ , or a repeating multilayer film 2B ₂₁ having a film thickness of λ / 4 or a film thickness close to this, which is composed of a low refractive index layer and a high refractive index layer in this order.
By laminating at least one layer, it can be used as a reflecting mirror. Here, if the films of the high-refractive index layer and the low-refractive index layer are written as H and L, respectively, “air (n ₀ ) -H (LH ... LH) -glass (n ) ”, Abbreviated as“ air-H (LH) ^q -glass ”. Here, "n ₁ = n ₃ =
...... = n _{2q + 1} = n _H ”,“ n ₂ = n ₄ = ... = n _2q = n
If we write " _L ", the energy reflectance for the central wavelength is
From the process of finding a general field boundary conditions, R = ^{_{[(n 0 n 3 n L 2q}} - n H 2 (q + 1)) / (n 0 n 3 n l 2q + n H 2 (q + 1) )] ² x 100 ... <1>.

When the reflectance in the case of q = 1, 2 is calculated using this equation <1>, R = 68 [%], q in the case of q = 1.
= 2, R = 93 [%] (where n ₀ = 1,
n ₃ = 1.52, n _L = 1.38, n _H = 2.35).

Next, the optical function of the hole-shaped recording pit will be described.

When a pit-shaped hole is formed in at least one layer of the repeating multilayer film of the high refractive index layer and the low refractive index layer by dry etching and the high refractive index layer, the low refractive index layer or both layers are removed, the pit portion is removed. The laser light incident on is transmitted. Therefore, when the laser light is positioned on the recording pit, the reflected light is reduced by the amount of the transmitted light, and the detection system can read it (the heterodyne system or the three-beam system is desirable for the detection system at this time).

On the other hand, in the medium structure having the metal film or the reflection layer composed of the repeated multilayer film of the high refractive index layer and the low refractive index layer, the laser light incident on the pit portion is the laser light incident on the bottom portion of the recording pit. A phase difference occurs with respect to the laser light reflected by the reflective layer and reflected by the unrecorded portion, and the laser light interferes with each other to reduce the amount of reflected light. Therefore, reproduction by the conventional push-pull method becomes possible.

Further, in the above-mentioned manufacturing process, the recording pits are formed by exposing and developing the photoresist in the above-mentioned conventional master making of the optical disc.
In the information recording medium according to the above example, by using the positive type photoresist used for forming the recording pits as a dry etching mask by reversing the Gaussian exposure state, It is possible to form small recording pits, which enables high density recording of information.

Further, in the exposure step, it is possible to manufacture the information recording medium one by one by the direct laser cutting method. First, the high-density and high-precision photomask is formed by using the dry etching method described above. It is also possible to manufacture and mass-produce by contact exposure method.

Since each information recording medium in each of the above embodiments can be manufactured by using a dielectric material having a high refractive index and a low refractive index, it has excellent reliability for long-term data storage.

Further, in each information recording medium in the above-mentioned embodiment, the recording pit has a medium structure for transmitting the laser beam, so that an optical gap is formed between the reflection surface of the unrecorded portion and the transmission surface of the recording portion. Since there is no phase difference, it is superior to the super-resolution optical system as a reproducing medium.

Here, in each of the above embodiments, the case where SiO ₂ is used as the transparent substrates 1 to 8 has been illustrated, but the present invention does not limit the material of the transparent substrate to SiO ₂ , and for example, polymethyl methacrylate. (PMMA), polycarbonate (PC), amorphous polyolefin (A
It may be one using a thermoreversible resin such as PO) or epoxy.

Further, in each of the above embodiments, the reflection film is made of Al, but this utilizes the fact that the reflectance is high with respect to the laser light of 680 [nm].
It is not limited to l. In addition to Al, Ag, Au,
Cu, In, Ti, V, Nb, Cr, Mo, W, Mn,
Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, P
at least one kind of t is used, or Si, G
By combining with a semiconductor such as e or a transparent dielectric material, the reflectance of light of a specific wavelength may be increased by the interference of the multilayer film.

Here, in each of the above embodiments, the high refractive index layer may be formed of a hydrogen-containing alloy of amorphous Si. In this case, when the average composition in the film thickness direction of the hydrogen-containing alloy of amorphous Si is represented by the general formula “Si _1-X H _X ”, x is an atomic percentage of “28/47 ≦ x ≦ 28/2.
Those set in the range of "9" are used. In this case, the refractive index is in the range of "4.0≤nx≤4.5".

Furthermore, in each of the above embodiments, the high refractive index layer may be formed of a hydrogen-containing alloy of microcrystallized Si. In this case, the hydrogen-containing alloy of microcrystallized Si has an x composition when the average composition in the film thickness direction is represented by the general formula "Si _1-X H _X ".
Is used in the range of “28/47 ≦ x ≦ 28/37” in atomic percent. In this case, the refractive index is in the range of "3.3≤nx≤3.5".

In each of the above embodiments, the high refractive index layer may be formed of a hydrogen-containing alloy of amorphous SiC. In this case, the hydrogen-containing alloy of amorphous SiC is
The average composition in the film thickness direction is expressed by the general formula “(Si C)
_1-X H _X ", x is an atomic percentage of" 40
/ 49 ≦ x ≦ 40/41 ”is used. In this case, the refractive index is "3.1 ≤ nx ≤ 4.1".
It will be in the range of.

Further, in each of the above embodiments, the high refractive index layer may be formed of a hydrogen-containing alloy of amorphous Si Ge. In this case, the hydrogen-containing alloy of amorphous Si Ge has an average composition in the thickness direction of the general formula "(Si Ge)
_1-X H _X ", x is 50 in atomic percent.
3/598 ≦ x ≦ 503/518 ”is used. In this case, the refractive index is "3.2 ≤ nx
≦ 3.8 ”.

Further, in each of the above embodiments, the high refractive index layer may be formed of a nitride of amorphous Si. In this case, when the average composition in the film thickness direction of the high refractive index layer of the amorphous Si nitride is represented by the general formula "Si _1-X N _X ", x is an atomic percentage of "0 ≤ x ≤ 4 The one set in the range of "/ 7" is used. In this case, the refractive index is in the range of "2.0≤nx≤3.82".

Further, in each of the above embodiments, the high refractive index layer may be formed of an oxide of amorphous Si. In this case, when the average composition in the film thickness direction of the high refractive index layer of an oxide of amorphous Si is represented by the general formula "Si _1-X O _X ", x is an atomic percentage of "0 ≤ x ≤ 2 The one set in the range of "/ 3" is used. In this case, the refractive index is in the range of “1.46 ≦ nx ≦ 3.82”.

Furthermore, in each of the above embodiments, the high refractive index layer is composed of a medium of low refractive index having a refractive index of n <1.5 and a medium of high refractive index having a refractive index of 1.5 ≦ n <3.0. , And a medium of a high refractive index layer having a refractive index of n ≧ 3.0, which has a uniform intermediate refractive index formed by mixing at least two kinds of media having different refractive indexes. Good.

In this case, LiF (1.39), NaF (1.31), and NaF (1.31), as the medium having a low refractive index of "n <1.5",
KF (1.32), RbF (1.40), CsF (1.48), CaF (1.3
2), RbCl (1.48), MgF ₂ (1.38), CaF ₂ (1.4
3), SrF ₂ (1.44), BaF ₂ (1.47), BaMgF
₄ (1.47), LiYF ₄ (1.45), Na ₂ SbF ₅ (1.47), S
iO ₂ (1.46), RbClO ₃ (1.46), NH ₄ ClO ₄ (1.4
_{8), LiClO 4 · 3 H} 2 O (1.48), KB 5 O 8 · 4
_{H 2 O (1.49), NH} 4 B 5 O 8 · 4H 2 O (1.42), Be
SO ₄・ 4H ₂ O (1.47), Li ₂ SO ₄・ H ₂ O (1.4
6), Li ₂ SeO ₄ · H ₂ O (1.46), LiKSO ₄ (1.4
6), LiNaSO ₄ (1.47), (NH ₄ CH ₃ ) Al (
SO ₂ ) ・ 12H ₂ O (1.46), KNa (C ₄ H ₄ O ₆ )
・ 4H ₂ O (1.49), (CH ₂ · CF ₂ ) n (1.43) are preferable. Here, the inside of () shows a refractive index.

Of these, CaF and L are particularly desirable.
iF, NaF, KF, MgF ₂ , and SiO ₂ .

As the refractive index layer having a refractive index of "1.5≤n <3.0", diamond carbon (2.0), ThF ₄
(1.5), NdF ₃ (1.61), CeF ₃ (1.63), PbF
₃ (1.77),

MgO (1.74), ZnO (1.99), BeO (1.7
2), Si ₂ O ₃ (1.55), SiO (2.0), ThO ₂ (1.86), T
iO ₂ (1.9), TeO ₂ (2.27), Al ₂ O ₃ (1.54), Y ₂
O ₃ (1.92), La ₂ O ₃ (1.9), CeO ₂ (2.2), Zr
O ₂ (1.97), Ta ₂ O ₅ (2.1), PbO (2.6), La ₂ O ₂
S (2.16), LiGaO ₂ (1.76), BaTiO ₃ (2.37),
SrTiO ₃ (2.4), PbTiO ₃ (2.67), KNbO ₃
(2.33), K (Ta. Nb) O ₃ (2.29), LiNbO ₃ (2.
30), LiTaO ₃ (2.175), Pb (Mg _1/3 Nb _2/3 ).
O ₃ (2.56), Pb (Mg _1/3 Ta _2/3 ) O ₃ (2.40), P
b (Zn _1/3 Nb _2/3 ) O ₃ (2.54), (Pb, La) (Z
r, Ti) O ₂ (2.51), PbGeO ₃ (2.02), Li ₂ G
eO ₃ (1.68), YAlO ₃ (1.93), MgAl ₂ O ₄ (1.7
3), BeAl ₂ O ₄ (1.74), CoFe ₂ O ₄ (2.37), L
a ₂ Be ₂ O ₅ (1.96), (Sr, Ba) Nb ₂ O ₆ (2.3
1), La ₂ Ti ₂ O ₇ (2.25), Nd ₂ Ti ₂ O ₇ (2.1
5), Ba ₂ TiSi ₂ O ₈ (1.762), Pb ₅ Ge ₃ O ₁₁
(2.12), PbNb ₄ O ₁₁ (2.41), Bi ₄ Ti ₃ O ₁₂ (2.7
0), Bi ₄ Ge ₃ O ₁₂ (2.07), Bi ₄ Si ₃ O ₁₂ (2.0
2), Y ₃ Al ₅ O ₁₂ (1.83), Y ₃ Ga ₅ O ₁₂ (1.93), Y
₃ Fe ₅ O ₁₂ (2.22), Gd ₃ Ga ₅ O ₁₂ (1.96), GdF
e ₅ O ₁₂ (2.20), (Gd, Bi) Fe ₅ O ₁₂ (2.20), B
a ₂ NaNb ₅ O ₁₂ (2.26), Pb ₂ KNb ₅ O ₁₂ (2.4
6), Sr ₂ KNb ₅ O ₁₅ (2.25), Ba ₂ LiNb ₅ O
₁₅ (2.32), K ₃ Li ₂ Nb ₅ O ₁₅ (2.21), Ba ₃ T
iNb ₄ O ₁₅ (2.36), Bi ₁₂ GeO ₂₀ (2.55), Bil ₂
SiO ₂₀ (2.54), Ca ₁₂ Al ₁₄ O ₃₃ (1.61),

AgCl (1.98), TlCl (2.19), CuC
l (1.99), LiBr (1.78), NaBr (1.64), KBr
(1.53), CsBr (1.66), AgBr (2.25), TlBr
(2.34), CuBr (2.16), NaI (1.77), KI (1.64),
CsI (1.73), AgI (2.18), TlI (2.78), CuI
(2.34), Tl (Br, I) (2.20), Tl (CL, Br)
(2.40), PbF ₂ (1.77), Hg ₂ Cl ₂ (2.62), La
F ₃ (1.82), CsPbCl ₃ (1.94), BaMgF ₄ (1.4
7), BaZnF ₄ (1.51), Ag ₂ HgI ₄ (2.4), Na
ClO ₃ (1.51), NaBrO ₃ (1.59), CdHg (SC
N) ₄ (2.04),

ZnSiP₂(2.95), ZnS (2.37), Zn
Se (2.61), CdSiP₂(2.95), CdS (2.49), Cd
Se (2.64), CdTe (2.61), HgS (2.89), GaSe
(2.98), LiInS₂(2.23), LiInSe₂(2.45),
CuAlS₂(2.48), CuAlSe₂(2.64), CuAl
Te₂(2.99), CuInS₂(2.53), CuInSe₂(2.
70), CuGaS₂(2.49), CuGaSe₂(2.72), A
gAlS₂(2.42), AgAlSe₂(2.59), AgAlT
e₂(2.90), AgInS₂(2.46), AgInSe₂(2.6
4), AgInTe₂(2.97), AgGaS₂(2.38), Ag
GaSe₂(2.61), AgGaTe₂(2.94), GeS
₃(2.11), As₂S₃(2.61), As₂Se₃(2.89), A
g₃AsS₃(2.59), CdGa₂S₃₄(2.395), Tl₃T
aS_Four(2.4), Tl₃TaSe_Four(2.71), Tl₃VS_Four
(2.95), Tl₃AsS_Four(2.65) Tl₃ AsSe_Four(2.9
3), Tl₃PSe_Four(2.93),

GaN (1.55), Si ₃ N ₄ (2.0), CaC
o ₃ (1.65), NaNO ₃ (1.60), Ba (NO ₃ ) ₂ (1.5
7), Sr (NO ₃ ) ₂ (1.58), Pb (NO ₃ ) ₂ (1.78)
, NaNO ₂ (1.65), Sr (NO ₂ ) ₂ · H ₂ O (1.5
6), LiIO ₃ (1.89), KIO ₃ (1.70), NH ₄ IO
₃ (1.78), KIO ₂ F ₂ (1.62), KIO ₃ · HIO
₃ (1.98), K ₂ H (IO ₃ ) ₂ Cl (1.88), LiB ₄ O ₇
(1.61),

K ₂ Mn ₂ (SO ₄ ) ₃ (1.57), Rb ₂ Mn
₂ (SO ₄ ) ₃ (1.60), Tl ₂ Mn ₂ (SO ₄ ) ₃ (1.80)
_{, (NH 4) 2 Mn 2} (SO 4) 3 (1.52), (NH 4) 2 C
d ₂ (SO ₄ ) ₃ (1.57), LiH ₃ (SeO ₃ ) ₂ (1.74), R
bH ₃ (SeO ₃ ) ₂ (1.67), NH ₄ H ₃ (SeO ₃ )
₂ (1.68), Sr ₂ S ₂ O ₆・₄ H ₂ O (1.53), KH ₂ P
O ₄ (1.51), KD ₂ PO ₄ (1.51), NH ₄ H ₂ PO
₄ (1.52), ND ₄ D ₂ PO ₄ (1.52), RbH ₂ PO
₄ (1.51), KH ₂ AsO ₄ (1.57), KD ₂ AsO ₄ (1.5
6), NH ₄ H ₂ AsO ₄ (1.58), RbH ₂ AsO ₄ (1.5
6), RbD ₂ AsO ₄ (1.57), CsH ₂ AsO ₄ (1.5
7), CsD ₂ AsO ₄ (1.55), KTiOPO ₄ (1.74),
RbTiOPO ₄ (1.75), (K, Rb) RbTiOPO
₄ (1.75), Ca ₅ (PO ₄ ) ₃ F (1.63), Ca ₄ La (P
O ₄ ) ₃ O (1.70), LiNdP ₄ O ₁₂ (1.60), KNdP ₄
O ₁₂ (1.59), NdP ₅ O ₁₄ (1.59),

CaMoO ₄ (1.99), PbMoO ₄ (2.41)
, CaWO ₄ (1.92), ZnWO ₄ (2.14), Gd ₂ (Mo
O ₄ ) ₃ (1.843), Tb ₂ (MoO ₄ ) ₃ (1.848), Bi ₂ (M
oO ₄ ) ₃ (2.28), K ₅ (Bi, Nd) (MoO ₄ ) ₄ (1.79)
, Pb ₂ MoO ₅ (2.18), Bi ₂ WO ₆ (2.5), YV
O ₄ (2.00), Ca ₃ (VO ₄ ) ₂ (1.86), Pb ₅ (GeO ₄ )
(VO ₄ ) ₂ (2.28),

Gd ₂ SiO ₅ (1.9), Al ₂ (SiO ₄ )
F (1.63), CaY ₄ (SiO ₄ ) ₃ O (1.83), CaLa ₄
(SiO ₄ ) ₃ O (1.86), SrLa ₄ (SiO ₄ ) ₃ O (1.7
9), (NaCa) Li (A, FeMn) ₈ (1.65), Be ₃
Al ₂ Si ₆ O ₁₈ (1.57),

C ₁₄ H ₁₀ (1.55), C ₂₄ H ₁₈ (1.52), CO (
NH ₂ ) ₂ (1.60), Ba (COOH _{) 2} (1.57), Sr (CO
OH) ₂ (1.55), Pb ₂ Sr (CH ₃ CH ₂ COO) ₆ (1.4
9), C ₄ H ₆ O ₆ (1.49), (NH ₄ CH ₂ COOH) ₃ H
₂ SO ₄ (1.56), C ₄ H ₃ N ₃ O ₄ (1.52), (CH ₂ ) ₆
N ₄ (1.59), (C ₆ H ₅ CO) ₂ (1.84), C ₆ H ₄ NO ₂
NH ₂ (1.76), C ₆ H ₄ (OH) ₂ (1.59), C ₆ H ₄ (NH ₄ ).
OH (1.67), C ₅ H ₃ NOCH ₃ NO ₂ (1.71), C ₆ H
₄ (CO ₂ ) ₂ HCs (1.67), C ₆ H ₄ (CO _{2) 2} HRb (1.
66), C ₆ H ₃ NO ₂ CH ₃ NH ₂ (1.70), C ₆ H ₃ C
H ₃ (NH _{2) 2} (1.62), C ₆ H ₂ (NO ₂ ) ₃ OH (1.68), K
_{H (C 8 H 4 O 4} ) (1.66), C 10 H 14 O (1.58), C 10 H
₁₁ N ₃ O ₆ (1.56), C ₁₀ H ₁₃ N ₅ O ₄ (1.52), C ₁₄ H ₁₇
It is preferably NO ₂ (2.04). Here, the inside of () shows a refractive index. Of these, Ti is particularly desirable.
O ₂ , Ta ₂ O ₅ , Si ₃ N ₄ , ZnS, Y ₂ O ₃ , Z
nSe, GaSe, CuInSe ₂ (2.70), CuGaS
₂ (2.49), CuGaSe ₂ (2.72), AgAlS ₂ (2.4
2), AgAlSe ₂ (2.59), AgAlTe ₂ (2.90), A
gInS ₂ (2.46), AgInSe ₂ (2.64), AgInT
e ₂ (2.97), AgGaS ₂ (2.38), AgGaSe ₂ (2.6
1), AgGaTe ₂ (2.94) and GeS ₃ (2.11).

Further, in this embodiment, the refractive index is "n≥
3.0 "high refractive index layers are Ge (4.01), Si (3.82),
Se (5.56), Te (4.85), ZnTe (3.05), HgSe
(3.75), PbS (3.5), PbTe (5.6), In ₅₇ Se ₄₃
(3.8), In ₃ Se ₂ (3.8), InSe (3.8), In ₂ S
b ₃ (4.1), GaSb (4.6), TlGaSe ₂ (3.0), A
g ₃ SbAgS ₃ (3.08), Tl ₃ AsSe ₃ (3.33), C
uGaTe ₂ (3.01), CuInTe ₂ (3.0 5), ZnS
iAs ₂ (3.22), ZnGeP ₂ (3.14), ZnGeAs ₂
(3.38), ZnSnP ₂ (3.21), ZnSnAs ₂ (3.53),
CdSiAs ₂ (3.22), CdGeP ₂ (3.20), CdGe
AS ₂ (3.56), CdSnP ₂ (3.14), CdSnAs
₂ (3.46), GaAs (3.42), GaSb (3.9), GaP
(3.35), InP (3.37), InAs (3.4), InSb (3.7
5), Sb ₂ S ₃ (3.0), Sb ₂ Te ₃ (5.0), (Ga,
Al) As (3.21 to 3.65), Ga (As, P) (3.29 to 3.
36), (Ga, Al) Sb (3.2 to 3.92), (InGa)
(AsP) (3.21 to 3.42), CdGeAs ₂ (3.60), Ge
₁₉ Sb ₃₈ Te ₄₃ (4.15), Ge ₁₈ Sb ₃₂ Te ₅₀ (4.28), G
e ₂₇ Se ₁₈ Te ₅₅ (3.05), In ₂₂ Sb ₃₃ Te ₄₅ (4.295)
, In ₂₂ Sb ₃₇ Te ₄₁ (4.968), In ₂₀ Sb ₃₇ Te
₄₃ (4.952), In ₃₂ Sb ₄₀ Te ₂₈ (3.04) 5, Sb ₅₆ Se
₄₀ Zn ₄ (4.234), Sb ₄₄ Se ₂₉ Zn ₂₇ (3.492), Sb
₃₄ Se ₅₈ Sn ₈ (5.068), Se ₅₂ Ge ₂₇ Sn ₂₁ (3.761)
, Te ₆₄ Sb ₆ Sn ₃₀ (3.147), Se ₆₆ Sb ₂₄ Ge
₁₀ (4.240), Te ₈₀ Se ₁₀ Sb ₁₀ (4.0), GeSb ₂ T
It is preferably e ₄ (4.7), TeO _x (3.8), and GeTe (4.4). Here, the inside of () shows a refractive index.

Of these, Ge and S are particularly desirable.
i, InSe.

[0120]

As described above, according to the information recording medium of the present invention, it is possible to effectively eliminate the influence of crosstalk and intersymbol interference due to sagging or blurring during the formation of an optical disk in the conventional example. According to the method for manufacturing an information recording medium of the present invention, it is possible to increase the recording density, and according to the information recording medium formed by the method,
In particular, it is possible to reduce the sag and blurring around the recording pits due to the transfer failure, and it is possible to manufacture a high-density and high-precision information recording medium. Therefore, the focus servo and the track servo can be stably applied. It is possible to obtain an excellent effect that is not possible in the past.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing a first embodiment of the present invention.
(A) is a partial sectional view showing the relationship between the multilayer film and the pit portion,
FIG. 1 (B) is an enlarged partial sectional view of a portion A in FIG. 1 (A).

FIG. 2 is a table showing the calculation results of the refractive index and the reflectance of various materials constituting each refractive index layer disclosed in FIG.

FIG. 3 is a table showing the calculation results of the refractive index and the reflectance of other materials constituting each refractive index layer disclosed in FIG.

FIG. 4 is a partial sectional view showing a second embodiment of the present invention.
(A) is a partial sectional view showing the relationship between the multilayer film and the pit portion,
FIG. 4B is an enlarged partial cross-sectional view of the portion A in FIG. 4A.

5 is a table showing the calculation results of the refractive index and the reflectance of various materials constituting each refractive index layer disclosed in FIG.

FIG. 6 is a table showing the calculation results of the refractive index and the reflectance of other materials constituting each refractive index layer disclosed in FIG.

FIG. 7 is a partial sectional view showing a third embodiment of the present invention.

8 is a diagram showing the SiO ₂ film thickness dependence of the reflectance and phase difference of the information recording medium in FIG. 7.

FIG. 9 is a partial cross-sectional view showing a fourth embodiment of the present invention (a low refractive index layer is leveled).

10 is a diagram showing the SiO ₂ film thickness dependence of the reflectance and phase difference of the information recording medium in FIG. 9.

FIG. 11 is a partial sectional view showing a fifth embodiment of the present invention.

12 is a diagram showing the SiO ₂ film thickness dependence of the reflectance and phase difference of the information recording medium in FIG. 11.

FIG. 13 is a partial cross-sectional view showing another example of the present invention in which a metal reflective film is used.

FIG. 14 is a partial cross-sectional view showing another example of the present invention in which a metal reflective film is used and the low refractive index layer is leveled.

FIG. 15 is a partial cross-sectional view showing another example of the case where a metal reflective film is used in another example of the present invention.

FIG. 16 is a table showing calculation results of respective reflectances and phase differences of a mirror part and a pit part in another example of the present invention.

FIG. 17 shows an example of a method for manufacturing an information recording medium in the present invention, FIG. 17 (A) is a diagram showing a first step, and FIG. 17 (B) is a diagram showing a second step. FIG. 17
FIG. 17C is a diagram showing the third step, and FIG.
It is a figure which shows a process, FIG.17 (E) is a figure which shows a 5th process, FIG.17 (F) is a figure which shows a 6th process, FIG.
FIG. 7 (G) is a diagram showing another sixth step, and FIG.
FIG. 11 is a diagram showing a seventh step following the other sixth step.

FIG. 18 is an explanatory diagram showing a cause of sagging or blurring of a pit portion in a conventional example.

FIG. 19 is an explanatory diagram showing a form of sagging or blurring of a pit portion in a conventional example.

[Explanation of symbols]

1, 2, 3, 4, 5, 6, 7, 8 Information recording medium 1A, 2A, 3A, 4A, 5A, 6A, 7A, 8A Transparent substrate 1B ₁ , 2B ₁ , 3B ₁ , 4B ₁ , 4B ₁ , 5B ₁ , 8
C high refractive index layers 1B ₂ , 2B ₂ , 3B ₂ , 4B ₂ , 4B ₂ , 5B ₂ , 6
C, 7C low refractive index layer 1B ₁₂ , 2B ₂₁ multilayer film 1C, 2C, 3D, 4D, 5D, 6E, 7E, 8E resin film 3C, 4C, 5C reflective layer 6B, 7B, 8B first metal reflective layer 6D, 7D, 8D Second metal reflective layer

Claims (17)

[Claims] 1. A transparent substrate, two or more multilayer films coated on the transparent substrate, in which a high refractive index layer and a low refractive index layer are repeated in this order, and a resin film laminated on the multilayer film. An information recording medium comprising: a high refractive index layer and at least one refractive index layer of the low refractive index layers having hole-shaped recording pits. 2. A transparent substrate, a multilayer film of two or more layers formed by coating the transparent substrate and repeating a low refractive index layer and a high refractive index layer in this order, and a resin film laminated on the multilayer film. An information recording medium comprising: a low refractive index layer and a high refractive index layer, wherein at least one refractive index layer has a hole-shaped recording pit. 3. A transparent substrate, two or more multilayer films coated on the transparent substrate and having a high refractive index layer and a low refractive index layer repeated in this order, and a resin film laminated on the multilayer film. An information recording medium, characterized in that at least one refractive index layer of the high refractive index layer and the low refractive index layer has a hole-shaped recording pit, and a reflective layer is coated on the multilayer film. . 4. A transparent substrate, a multilayer film of two or more layers formed by coating the transparent substrate and repeating a low refractive index layer and a high refractive index layer in this order, and a resin film laminated on the multilayer film. And at least one of the low-refractive index layer and the high-refractive index layer has a hole-shaped recording pit, at least the reflective layer is coated on at least the multilayer film information recording Medium. 5. The film thickness of each of the high refractive index layer and the low refractive index layer is λ / 4 n (λ is the wavelength of the laser beam, n is the refractive index of the refractive index layer). Claims 1, 2, 3
Alternatively, the information recording medium according to item 4. 6. The high refractive index layer is formed of a hydrogen-containing alloy of amorphous Si, and the hydrogen-containing alloy of amorphous Si has an average composition in the thickness direction of the general formula “S”.
i _1−X H _X ″, the x is set in the range of “28/47 ≦ x ≦ 28/29” in atomic percent. The information recording medium according to 3, 4, or 5. 7. The high-refractive index layer is formed of a microcrystallized Si-containing hydrogen-containing alloy, and the microcrystallized Si-containing hydrogen-containing alloy has an average composition in the thickness direction of the general formula “Si _{1 -X} H
_When represented by " _X ", the above x is "28 /" in atomic percent.
The information recording medium according to claim 1, 2, 3, 4 or 5, wherein the information recording medium is set in a range of 47 ≤ x ≤ 28/37 ". 8. The high refractive index layer is formed of a hydrogen-containing alloy of amorphous SiC, and the amorphous SiC is formed.
In the hydrogen-containing alloy of C, when the average composition in the film thickness direction is represented by the general formula “(Si C) _1-X H _X ”, the x is “40/49 ≦ x ≦ 40/41” in atomic percent. The information recording medium according to claim 1, 2, 3, 4, or 5, characterized in that the information recording medium is set in the range. 9. The high refractive index layer is formed of amorphous Si Ge.
This amorphous S is formed with the hydrogen-containing alloy of
The hydrogen-containing alloy of i Ge has the above-mentioned x when the average composition in the film thickness direction is represented by the general formula "(Si Ge) _1-X H _X ".
6. The information recording medium according to claim 1, wherein the atomic percentage is set within the range of "503 / 598≤x≤503 / 518". 10. The high refractive index layer is formed of a nitride of amorphous Si, and the nitride of the amorphous Si has an average composition in the film thickness direction represented by the general formula “Si”.
_1-X N _X ", wherein x is set in the range of" 0 ≤ x ≤ 4/7 "in atomic percent. Alternatively, the information recording medium described in 5. 11. The high refractive index layer is formed of an oxide of amorphous Si, and the oxide of the amorphous Si has an average composition in the film thickness direction represented by the general formula “Si”.
_1-X O _X ", wherein x is set in the range of" 0 ≤ x ≤ 2/3 "in atomic percent. Alternatively, the information recording medium described in 5. 12. The high refractive index layer has a refractive index of n <1.5.
At least two types of medium having a low refractive index, a medium having a high refractive index of 1.5 ≦ n <3.0, and a medium having a high refractive index layer having a refractive index of n ≧ 3.0. An information recording medium according to claim 1, 2, 3, 4 or 5, characterized in that it has a uniform intermediate refractive index formed by mixing the mediums of (1) and (2). 13. A transparent substrate, on which a first metal reflective film, a low refractive index layer, a second metal reflective film and a resin film are sequentially coated, and hole-shaped recording pits are formed in the first metal reflective film. An information recording medium characterized by: 14. A transparent substrate, on which a first metal reflective film, a high refractive index layer, a second metal reflective film and a resin film are sequentially coated, and hole-shaped recording pits are formed in the first metal reflective film. An information recording medium characterized by: 15. A repeating multilayer film comprising a high-refractive index layer and a low-refractive index layer, or a low-refractive index layer and a high-refractive index layer in this order is formed on a transparent substrate, and at least one or more layers thereof are formed, and then a photoresist layer is formed. After stacking, the light corresponding to the writing information is irradiated to expose the photoresist layer in the light irradiation area, and then the exposed photoresist layer is developed to expose the photoresist layer in the light irradiation area. The high refractive index layer or the low refractive index layer is exposed while being removed, and then etching is performed to form a recess in at least one of the high refractive index layer or the low refractive index layer in the removed region of the photoresist layer. A method for manufacturing an information recording medium, characterized by: 16. The method of manufacturing an information recording medium according to claim 15, wherein the etching method is an ion milling method using argon plasma or the like. 17. The method for manufacturing an information recording medium according to claim 15, wherein the etching method is a reactive ion etching method using carbon tetrachloride.