JPH10312585A - Stamper for manufacturing optical recording medium, master for stamper and manufacture of optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an irregularity in a pit width even in an optical recording medium having a fine uneven pattern containing a short pit and to improve the degradation of an RF signal. SOLUTION: A photosensitive material layer 2 applied to a board is subjected to light a recording exposure operation by means of recording. After that, the photosensitive material layer 2 is developed, and an uneven pattern 4 corresponding to a fine uneven pattern on an optical recording medium as a target is formed. Then, a thin film is deposited along the uneven surface of the uneven pattern 4, a reduced uneven pattern 14 in which the width of the uneven pattern 4 is reduced is formed, and a master for a stamper used to manufacture the optical recording medium is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a stamper for producing an optical recording medium such as an optical disk, a stamper master, and a method for producing an optical recording medium.

[0002]

2. Description of the Related Art Optical recording media such as ROM (Read Onl)
In a rewritable optical disk having a phase change recording layer or a rewritable optical disk having a phase change recording layer, pits and / or grooves in a required format, that is, a fine uneven pattern are formed. The fine concavo-convex pattern may be formed by injection molding using a stamper having a concavo-convex pattern formed by inverting the fine concavo-convex pattern, by forming the fine concavo-convex pattern simultaneously with the molding of the optical disk, or by a 2P method (photopoly In other words, a method of applying an ultraviolet curable resin on a substrate, pressing the stamper to transfer and form a fine concavo-convex pattern, and irradiating with ultraviolet light is employed.

In forming the stamper, first, a master for transferring and forming the stamper is manufactured. The production of this master
Normally, a photosensitive material layer is formed by a photoresist on a glass substrate having a smooth surface, and finally obtained, that is, exposure recording is performed by a desired fine concavo-convex pattern, and development processing is performed to perform a fine concavo-convex pattern. To form a metal layer by, for example, Ni plating, and to produce a stamper by peeling off from the master, or to temporarily produce a master disk, and transfer and produce a mother disk using this master disk. A similar stamper is manufactured by transfer using this motherboard.

[0004]

In order to increase the recording density of the optical recording medium, the exposure of the photosensitive material layer in the preparation of the master, that is, the recording exposure, requires the recording light having the shortest possible wavelength. And a numerical aperture N. of an optical system (objective lens) for converging and irradiating the recording light to the photosensitive material layer. A. Must be large. At present, the light source having a short exposure recording wavelength is a wavelength of 351 nm of Ar and Kr lasers. In addition, the numerical aperture of the objective lens N.P. A. Is 0.90, which is almost the limit in air.

On the other hand, the pit width of a fine concavo-convex pattern recorded on an optical disk depends on the pit length. That is, when the pit length is short, the exposure amount is accordingly reduced, and the pit width is also reduced. As described above, if the width of a short pit is too narrow, the RF (high frequency) signal is severely deteriorated. For example, regarding exposure recording of a DVD (Digital Video Disc), the wavelength 351 nm and the numerical aperture N.P. A. But,
0.90 and the recording light spot diameter is 0.47 μm,
Even with the shortest pit length of 0.4 μm in DVD, thinning of the width is negligible. This is because the shortest pit length of this DVD has reached about 85% of the spot diameter of the recording light. However, when exposure recording is performed in a higher-density format, the pit width of a pit having a length of less than 0.4 μm becomes smaller due to the problem of the exposure amount, and particularly, the deterioration of the RF signal becomes remarkable.

At the same time, as the pit length becomes shorter and the exposure amount becomes smaller, there is a problem that the variation of the exposure width, that is, the pit width due to the variation of the exposure amount becomes larger. This will be described with reference to FIG. FIG. 23A shows an exposure amount distribution in an exposure spot when a pit length is long and a relatively large exposure amount is obtained. In this case, the exposure amount, shows a case in which variations between the curves a ₁ and the curve a _2. Further, FIG. B is a pit length indicates the exposure amount distribution of the exposure spot when short exposure amount is small, shows a case where the exposure amount is varied between the curved b ₁ and the curve b _2. In FIG. 23, a level indicated by a broken line curve c indicates a threshold value of exposure at which pits of the photosensitive material layer (photoresist) can be formed. Therefore, when the exposure amount is large i.e. pit length is large, the ratio in as shown in FIG. 23A, the exposure amount distribution when varying from a ₁ to a _2, a pit formation width changes from W _1s to W _2s When the exposure amount is small, that is, when the pit length is short, FIG.
As shown in the figure, when the distribution of the exposure amount changes from b ₁ to b ₂ , the pit formation width changes from W _{1w to} W _2w. Larger than when the amount is large.

Therefore, it is conceivable to reduce the variation of the above-mentioned pits having a pit length of less than 0.4 μm by sufficiently increasing the exposure intensity of the exposure light source. In addition, when the exposure amount is increased, the distribution in FIG. 23B is made closer to the distribution in FIG. 23A, so that the width of short pits can be increased, while the width of long pits increases. Since the pits become saturated, the variation in the width between the short pits and the long pits is also reduced, thereby increasing the effect of reducing jitter. However, when the exposure intensity of the exposure light source is increased as described above, the pit width is increased as a whole, and interference between pits (intersymbol interference and crosstalk) is increased, which does not lead to improvement of the RF signal.

For the reasons described above, it has been difficult to record an optical recording medium having a density exceeding that of a DVD, for example, an optical disk, using a general exposure apparatus.

In the present invention, the recording spot diameter of 85
% Or less, the pit width variation can be improved and the RF signal deterioration can be improved even in an optical recording medium having a fine uneven pattern including extremely short pits of less than 0.40 μm having a length of about 0.4% or less. To be able to.

Further, in the present invention, the fine uneven pattern has a length of about 85% or less of 0.40 μm
An optical recording medium that is useful when the groove width is sufficiently small compared to the spot diameter of the recording exposure described above, even in the case of a fine concave-convex pattern that does not include a very short pit less than, for example, only the groove. An object of the present invention is to provide a manufacturing stamper, a stamper master, and a method of manufacturing an optical recording medium.

[0011]

In the method of manufacturing a stamper master for producing an optical recording medium according to the present invention, a step of performing recording exposure with a recording light on a photosensitive material layer applied on a base, and thereafter performing a photosensitive exposure. Forming a concavo-convex pattern corresponding to the fine concavo-convex pattern on the intended optical recording medium by performing a developing process on the conductive material layer, and depositing a thin film along the concavo-convex surface of the concavo-convex pattern to reduce the width of the concavo-convex pattern And a step of forming a reduced reduced concavo-convex pattern, thereby producing a stamper master for producing an optical recording medium.

Further, in the method of manufacturing a stamper for producing an optical recording medium according to the present invention, a step of performing recording exposure with a recording light on a photosensitive material layer applied on a substrate, and thereafter performing a developing process on the photosensitive material layer Forming a concavo-convex pattern corresponding to the fine concavo-convex pattern on the target optical recording medium, and depositing a thin film along the concavo-convex surface of the concavo-convex pattern to reduce the width of the concavo-convex pattern. Forming a master for stamper production through a step of forming a stamper, and a step of producing a stamper by transferring the master for stamper production to produce a stamper for producing an optical recording medium.

Further, in the method of manufacturing a stamper for producing an optical recording medium according to the present invention, a step of performing recording exposure with a recording light on a photosensitive material layer applied on a substrate, and thereafter performing a developing process on the photosensitive material layer Performing a step of forming a concave and convex pattern corresponding to the fine concave and convex pattern on the target optical recording medium to produce a master for stamper production; a step of producing a master disk by transferring the master for stamper production; A step of manufacturing a mother board by transferring the board, and further a step of depositing a thin film along the uneven surface of the uneven pattern transferred to the mother board to obtain a reduced uneven pattern in which the width of the uneven pattern is reduced. And a step of producing a stamper by transferring a mother disk, to produce an optical recording medium producing stamper.

Further, in the method of manufacturing an optical recording medium according to the present invention, the stamper obtained through the step of forming a reduced uneven pattern by depositing a thin film along the uneven surface of the uneven pattern according to the present invention described above. To obtain an optical recording medium by a photopolymer method or an injection molding method.

According to the above-mentioned method of the present invention, a reduced uneven pattern is formed by forming a thin film on the uneven pattern on the master or mother disk for forming a stamper for obtaining an optical recording medium. In the exposure recording for forming the master, the width can be made large. That is, for example, even when obtaining an optical recording medium having a pit length of less than 0.40 μm, which corresponds to less than 85% of the exposure spot diameter, the width of the concavo-convex pattern in the exposure recording for forming the master is large. 23, the exposure intensity can be sufficiently increased, and as described with reference to FIG. 23, the variation in the width of the uneven pattern can be improved. Also,
Since the exposure intensity can be sufficiently increased, it is possible to form a so-called "clear" pattern. Therefore, the fine uneven pattern of the finally obtained optical recording medium is improved in the variation in width, and is formed as a fine uneven pattern having a so-called "clearness" of the pattern, so that the RF characteristics are improved.

In the stamper finally obtained, the concavo-convex pattern is a pattern whose width is reduced as compared with the pattern at the time of recording exposure. However, the disadvantage that the interference between pits is increased and the mutual interference between pits is increased is also avoided. Therefore, according to the present invention, the RF signal can be reliably improved.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a method for producing a master for a stamper for producing an optical recording medium according to the present invention, a step of performing recording exposure with a recording light on a photosensitive material layer applied on a base, A step of performing a development process on the layer to form a concavo-convex pattern corresponding to the fine concavo-convex pattern on the intended optical recording medium, and depositing a thin film along the concavo-convex surface of the concavo-convex pattern to reduce the width of the concavo-convex pattern And forming a reduced concavo-convex pattern, a master for a stamper for producing an optical recording medium is produced.

Further, in the method of manufacturing a stamper for producing an optical recording medium according to the present invention, a step of performing recording exposure with a recording light on a photosensitive material layer applied on a substrate, and thereafter performing a developing process on the photosensitive material layer Forming a concavo-convex pattern corresponding to the fine concavo-convex pattern on the target optical recording medium, and depositing a thin film along the concavo-convex surface of the concavo-convex pattern to reduce the width of the concavo-convex pattern. Forming a stamper for producing an optical recording medium through a step of producing a stamper producing master through the step of forming a stamper, and a step of producing a stamper by transferring the master for stamper production.

Further, in the method of manufacturing a stamper for producing an optical recording medium according to the present invention, a step of performing recording exposure with a recording light on a photosensitive material layer applied on a substrate, and thereafter performing a developing process on the photosensitive material layer Performing a step of forming a concave and convex pattern corresponding to the fine concave and convex pattern on the target optical recording medium to produce a master for stamper production; a step of producing a master disk by transferring the master for stamper production; A step of manufacturing a mother board by transferring the board, and further a step of depositing a thin film along the uneven surface of the uneven pattern transferred to the mother board to obtain a reduced uneven pattern in which the width of the uneven pattern is reduced. And a step of producing a stamper by transferring a mother disk, to produce an optical recording medium producing stamper.

Further, in the method of manufacturing an optical recording medium according to the present invention, the stamper obtained through the step of forming a reduced uneven pattern by depositing a thin film along the uneven surface of the uneven pattern according to the present invention described above. To obtain an optical recording medium by a photopolymer method or an injection molding method.

The recording exposure for the photosensitive material layer is performed at a wavelength of 35.
This is performed by using a recording light of 0 nm or more to obtain a concave-convex pattern for format production including pits having a length of less than 0.40 μm.

The above-mentioned thin film for forming the concavo-convex pattern can be formed by sputtering or chemical plating.

An example of a method of manufacturing a master for a stamper for producing an optical recording medium according to the present invention and a stamper for producing an optical recording medium using the master will be described with reference to FIGS. Each example of manufacturing an optical disk will be described. First, as shown in FIG.
A substrate 1 having a smooth main surface 1s, for example, a glass substrate is prepared, and a photosensitive material layer, for example, a positive photoresist 2 is applied on the main surface 1s to a uniform thickness by a spin coating method or the like. Then, the recording light L is applied to the photosensitive material layer 2 in a pattern having a width larger than the width of the fine concavo-convex pattern, which corresponds to the fine concavo-convex pattern of the optical recording medium finally obtained. Exposure is recorded through 3.

As shown in FIG. 2, a developing process is performed on the photoresist 2 to form an uneven pattern 4 having pits formed in the exposed portions. After that, the entire surface is irradiated with deep UV (far ultraviolet light).

Subsequently, the surface of the photoresist 2 is treated with a silane coupling agent, and as shown in FIG.
To form At this time, the hydroxyl groups generated on the photoresist surface by the deep UV irradiation performed previously form a hydrogen bond with the hydroxyl groups of the silane coupling agent, so that the two adhere tightly.

As shown in FIG. 4, a thin film 7 is applied to the master 6 treated with the silane coupling agent to reduce the width of the uneven pattern 4, thereby forming a reduced uneven pattern 14. . The thin film 7 can be formed by chemical plating or sputtering of Ni.
The chemical plating of Ni is a plating method in which metal ions are reduced by electrons released by an oxidation reaction of a reducing agent contained in a solution and deposited as a metal film. For example, in a solution in which nickel chloride and sodium hypophosphite are mixed together with a pH adjuster and a surfactant, H ₂ PO ₂ ⁻ → H ₂ PO ₃ ²⁻ + 2e ⁻ (oxidation reaction) Ni ²⁺ + 2e ⁻ → Ni ↓ (Reduction reaction) The Ni thin film 7 is deposited by the reaction shown in FIG. In this way, the Ni thin film 7 is firmly applied to the photoresist 2 via the silane coupling agent, and the thickness of the thin film is selected to be smaller than the width of the concave portion of the concave and convex pattern 4 described above. The concave / convex pattern 14 having the concave portion is formed.

As shown in FIG. 5, the surface of the Ni thin film 7
For example, an oxidation treatment using a dichromic acid solution is performed to form the release layer 8.
To form

Then, an electroplating of a metal, for example, Ni is applied thereon to a thickness sufficient to embed the reduced concavo-convex pattern 14, and as shown in FIG.
From the release layer 8 of the thin film 7
The stamper 9 on which the concavo-convex pattern 24 to which the pattern 4 has been transferred is formed is formed.

Although not shown, the stamper 9 thus obtained is placed in an injection molding die, and a resin such as polycarbonate is injected, so that fine irregularities on which the irregular pattern 24 of the stamper 9 is transferred are obtained. The target optical recording medium 10 on which the pattern 34 is formed, for example, an optical disk is obtained.

As shown in FIG. 8, a reflective film 11 made of, for example, an Al film is applied to the surface of the optical recording medium 10 by sputtering, vapor deposition, or the like, and as shown in FIG. For example, a protective film 12 made of an ultraviolet curable resin is applied. In this way, an optical recording medium having the desired fine uneven pattern 34, for example, the optical disk 10 is obtained.

In the exposure of the photosensitive material layer 2 in the method of the present invention, since the width is increased, an optimum pit width, that is, a pit width that minimizes the jitter value indicating the fluctuation of the RF signal is obtained. Exposure can be performed with a light intensity higher than the exposure intensity. Since the exposure intensity can be increased in this way, as is apparent from the description of FIG. 23, it is clear that the width variation can be avoided and a short pit, that is, a pit having a pit length of 85% or less of the exposure spot is obtained. Also, a pit having a long pit length and a pit having a small variation in width can be formed.

Then, in the optical recording medium 10 thus obtained, the Ni thin film 7 in FIG. 4 is adjusted so that the width of the fine concavo-convex pattern 34 becomes an optimum value, that is, the width in which the jitter is minimized. The choice of thickness is made.

In the above-described example, the stamper 9 for molding the optical recording medium, for example, the optical disk 10 is formed by direct transfer from the master 6, but the master disc is transferred from the master in consideration of the wear of the stamper 9. Then, a mother board is transferred from the master board to form the stamper 9 and a large number of stampers 9 can be manufactured from the mother board.

An example of this case will be described with reference to FIGS. In this case as well, as described with reference to FIG. 1, first, as shown in FIG. 10, a substrate 1 having at least one main surface 1s smoothed, for example, a glass substrate is prepared. An active material layer, for example, a positive photoresist 2 is applied to a uniform thickness by a spin coating method or the like. In the present invention, the photoresist 2 is exposed and recorded with the recording light L through the optical system, that is, the objective lens 3, in a pattern having a width larger than the width of the fine concavo-convex pattern of the optical recording medium to be finally formed. I do. Also in this case, this exposure is performed with a light intensity larger than the exposure intensity for obtaining the optimum pit width, that is, the pit width that minimizes the jitter value indicating the fluctuation of the RF signal.

As shown in FIG. 11, a development process is performed on the photosensitive material layer 2 to form a concavo-convex pattern 4. Next, in this example, the concave and convex pattern 4 is embedded,
A metal layer such as a Ni layer by chemical plating and electroplating is applied to a sufficient thickness, and this is peeled off from the photosensitive material layer 2 as shown in FIG.
Is formed, for example, Ni on which the concave / convex pattern 54 to which
A master board 50 is manufactured.

As shown in FIG. 13, the surface of the master disk 50 having the concave / convex pattern 54 is oxidized with, for example, a dichromic acid solution to form a release layer 55. Then, a metal such as Ni is coated on the release layer 55 with the concavo-convex pattern 5.
For example, electroplate to a thickness sufficient to embed 4
As shown in FIG. 14, the metal layer is peeled from the peeling layer 55, and the concave / convex pattern 6 on which the concave / convex pattern 54 has been transferred.
The mother board 60 made of, for example, Ni on which the substrate 4 is formed is manufactured.

On the concavo-convex pattern 64 of the mother board 60, a thin film 17 is applied by, for example, chemical plating or sputtering of Ni to reduce the pits of the concavo-convex pattern 4, thereby forming a reduced concavo-convex pattern 94. I do.

As shown in FIG. 16, the thin film 17 of the mother board 60, in this example, the surface of the Ni layer is oxidized with, for example, a dichromic acid solution to form a peeling layer 55. A metal, for example, Ni is electroplated to a thickness sufficient to embed the uneven pattern 64 thus subjected to the peeling process, and the metal layer is peeled from the peeling layer 55 as shown in FIG. Then, a stamper 70 made of, for example, Ni, on which the concavo-convex pattern 74 to which the reduced concavo-convex pattern 94 has been transferred is formed.

Although not shown, the stamper 70 thus obtained is placed in an injection mold, and a resin such as polycarbonate is injected to transfer the concave / convex pattern 74 of the stamper 70 to the purpose. Fine uneven pattern 34
The optical recording medium 10 on which is formed, for example, an optical disk is obtained.

As shown in FIG. 19, a reflective film 11 of, for example, an Al film is applied to the surface of the optical recording medium 10 by sputtering or the like, and as shown in FIG.
Protective film 1 made of, for example, an ultraviolet curable resin on reflective film 11
2 is applied. Thus, an optical recording medium, for example, the optical disk 10 is obtained.

Also in this example of the method, the thickness of the Ni thin film 17 in FIG. 15 is adjusted so that the width of the finally formed fine concavo-convex pattern 34 is an optimum value, that is, the width that minimizes the jitter. Is selected.

Also in this case, the stamper 70
And the optical recording medium 10 can be obtained by the 2P method.

According to the method of the present invention described above, it is possible to form an optical disk having a small difference in pit width depending on the pit length and having pits with small interference between pits during reading. Here, the thickness of the thin films 7, 17 for forming the reduced concavo-convex pattern will be considered. Now, FIG.
As shown in FIG. 1, the thickness of a thin film formed on a plane parallel to the plate surface is represented by a, and the width of the bottom surface of a pit determined by the gamma characteristic of a recording optical system, ie, a photosensitive agent (photoresist). Is W, and the average inclination of the side surface of the pit is θ. The thickness b of the thin film formed on the side surface of the pit has a minimum value a × cos when the film is formed with perfect directivity.
θ, and the thickness when a film having no directivity is formed is a. That is, the thickness b of the thin film formed on the side surface of the pit is in the range of (Equation 1) below.

[0044]

## EQU1 ## a × cos θ <b <a

When the film has perfect directivity, the pits do not shrink, but since there is no such film forming process, the pits do necessarily shrink. Therefore, for the sake of simplicity, consider a case where the film has no directivity at all. In order to reproduce a signal from a pit, it is necessary to form a film so that the bottom of the pit is not lost due to the reduction of the pit. At this time, since there is no directivity at all, a film having a thickness a is also formed on the side surface of the pit, and in this case, the film thickness at which the bottom surface of the pit disappears becomes (Equation 2).

[0046]

## EQU2 ## W × sin θ / {2 × (1-cos θ)}

That is, it must be (Equation 3).

A <W × sin θ / {2 × (1-cos θ)}

At this time, the width m of the bottom surface of the pit reduced by the film formation becomes (Equation 4).

[0049]

M = W−2 × a × tan (θ / 2)

As described above, the pits can be reduced, that is, a reduced concavo-convex pattern can be formed in proportion to the increase in the film thickness of the thin films 7 and 17.

According to the above-described method of the present invention, a reduced concavo-convex pattern is formed by forming a thin film on a concavo-convex pattern on a master or mother disc for forming a stamper for obtaining an optical recording medium. In the exposure recording for forming the master, the width can be made large. That is, for example, even when obtaining an optical recording medium having a pit length of less than 0.40 μm, which corresponds to less than 85% of the exposure spot diameter, the width of the concavo-convex pattern in the exposure recording for forming the master is large. 23, the exposure intensity can be increased, and as described with reference to FIG. 23, the variation in the width of the uneven pattern can be improved. Further, since the exposure intensity can be sufficiently increased, it is possible to form a so-called "clear" pattern. Therefore, the fine uneven pattern of the finally obtained optical recording medium is improved in the variation in width, and is formed as a fine uneven pattern having a so-called "clearness" of the pattern, so that the RF characteristics are improved.

As described above, according to the method of the present invention, a thin film is formed on the pits and / or grooves of the master or mother disk for forming a stamper for obtaining an optical recording medium. The width of the pits and / or grooves can be smaller than the width obtained by exposure recording. Therefore, according to the method of the present invention, even when obtaining an optical recording medium having a pit length including a pit length of less than 0.40 μm, in the exposure recording, the exposure amount larger than the finally obtained pit width is required. Thus, the optical recording medium can be reliably obtained.

In the example described above, the fine uneven pattern 3
4 is formed thereon, and the reflective film 11 and the protective film 12 are formed thereon.
The present invention can be applied to a case where an optical recording medium having a recording layer made of a phase change material or the like formed on a fine uneven pattern 34 is obtained. The method is not limited to the example described above.

The present invention is useful for forming a fine concavo-convex pattern having pits with short pit lengths, but can be applied to forming a groove having a fine width.

[0055]

As described above, according to the method of the present invention,
For example, when obtaining an optical recording medium in a format including a pit length of less than 0.40 μm,
At the time of the exposure recording, since it can be formed with an exposure amount larger than the width of the pit finally obtained,
It is possible to reliably obtain an optical recording medium having a required fine uneven pattern without variation in width.

Therefore, by applying the present invention, the jitter of the RF signal can be effectively reduced even when recording a format including a pit length of 85% or less of the spot diameter of the exposure recording light. .

At present, exposure light having a wavelength of 351 nm or less has not been put into practical use. However, even if a wavelength shorter than 351 nm has been developed and put into practical use, the recording exposure has been accompanied by this. It is anticipated that significant changes will be required in materials, processes, environmental management, etc. for this purpose, and it is expected that industrial problems will increase. However, according to the present invention, depending on the shortening of the recording wavelength, Without this, there is a great industrial advantage that exposure recording can be performed stably in a current wavelength range while maintaining a sufficient margin for a high-density optical recording medium such as an optical disk.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of one step for explaining an example of the method of the present invention.

FIG. 2 is a schematic cross-sectional view of one step for explaining an example of the method of the present invention.

FIG. 3 is a schematic cross-sectional view of one step for explaining an example of the method of the present invention.

FIG. 4 is a schematic cross-sectional view of one step for explaining an example of the method of the present invention.

FIG. 5 is a schematic cross-sectional view of one step for explaining one example of the method of the present invention.

FIG. 6 is a schematic cross-sectional view of one step for explaining an example of the method of the present invention.

FIG. 7 is a schematic cross-sectional view of one step for explaining an example of the method of the present invention.

FIG. 8 is a schematic cross-sectional view of one step for explaining one example of the method of the present invention.

FIG. 9 is a schematic cross-sectional view of one step for explaining an example of the method of the present invention.

FIG. 10 is a schematic cross-sectional view of one step for explaining another example of the method of the present invention.

FIG. 11 is a schematic cross-sectional view of one step for explaining another example of the method of the present invention.

FIG. 12 is a schematic cross-sectional view of one step for explaining another example of the method of the present invention.

FIG. 13 is a schematic cross-sectional view of one step for explaining another example of the method of the present invention.

FIG. 14 is a schematic cross-sectional view of one step for explaining another example of the method of the present invention.

FIG. 15 is a schematic cross-sectional view of one step for explaining another example of the method of the present invention.

FIG. 16 is a schematic cross-sectional view of one step for explaining another example of the method of the present invention.

FIG. 17 is a schematic cross-sectional view of one step for explaining another example of the method of the present invention.

FIG. 18 is a schematic cross-sectional view of one step for explaining another example of the method of the present invention.

FIG. 19 is a schematic cross-sectional view of one step for explaining another example of the method of the present invention.

FIG. 20 is a schematic cross-sectional view of one step for explaining another example of the method of the present invention.

FIG. 21 is an explanatory diagram of the relationship between pits and film formation in the method of the present invention.

FIG. 22 is an explanatory diagram of the relationship between pits and film formation in the method of the present invention.

23A and 23B are distribution curve diagrams of recording exposure amounts.

[Explanation of symbols]

Reference Signs List 1 base, 2 photosensitive material layer (photoresist), 3 objective lens, 4 concave / convex pattern, 8 release layer, 9 stamper, 10 optical recording medium, 14 reduced concave / convex pattern, 2
4 uneven pattern, 34 fine uneven pattern, 50 master board, 54 uneven pattern, 55 release layer, 60 mother board, 64 uneven pattern, 70 stamper, 94 reduced uneven pattern

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shin Masuhara 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation

Claims (10)

[Claims] 1. A step of recording and exposing a photosensitive material layer applied on a substrate with a recording light, and then performing a developing process on the photosensitive material layer to form a fine uneven pattern on a target optical recording medium. Optical recording characterized by comprising a step of forming a corresponding uneven pattern and a step of depositing a thin film along the uneven surface of the uneven pattern to form a reduced uneven pattern having a reduced width of the uneven pattern. A method for producing a master for a stamper for producing a medium. 2. A step of recording and exposing a photosensitive material layer applied on a substrate with a recording light, and thereafter performing a developing process on the photosensitive material layer to form a fine uneven pattern on a target optical recording medium. Forming a master for stamper production through a step of forming a corresponding uneven pattern, and a step of depositing a thin film along the uneven surface of the uneven pattern to form a reduced uneven pattern in which the width of the uneven pattern is reduced. A method for producing a stamper for producing an optical recording medium, comprising: a step of producing a stamper by transferring the master for producing the stamper. 3. A step of recording and exposing a photosensitive material layer applied on a substrate with a recording light, and thereafter performing a developing process on the photosensitive material layer to form a fine uneven pattern on a target optical recording medium. Forming a corresponding master pattern by forming a corresponding concavo-convex pattern; manufacturing a master board by transferring the master for stamper manufacturing; manufacturing a mother board by transferring the master board; A step of depositing a thin film along the uneven surface of the uneven pattern transferred to the board to obtain a reduced uneven pattern having a reduced width of the uneven pattern; and a step of manufacturing a stamper by transferring the mother board. A method for producing a stamper for producing an optical recording medium, comprising: 4. An optical recording medium obtained by a photopolymer method or an injection molding method using a stamper obtained through a step of forming a reduced uneven pattern by depositing a thin film along the uneven surface of the uneven pattern. Manufacturing method of recording medium. 5. The recording light exposure for the photosensitive material layer is performed by using a recording light having a wavelength of 350 nm or more.
The method for producing a stamper master for producing an optical recording medium according to claim 1, wherein a concave / convex pattern for producing a format including pits having a length smaller than the length is obtained. 6. The recording exposure on the photosensitive material layer is performed by a recording light having a wavelength of 350 nm or more.
3. The method according to claim 2, wherein the pattern forming concave / convex pattern including pits having a length less than the length is formed. 7. The recording exposure on the photosensitive material layer is performed by a recording light having a wavelength of 350 nm or more, and
4. The method of manufacturing a stamper for producing an optical recording medium according to claim 3, wherein a concave / convex pattern for producing a format including pits having a length smaller than the length is formed. 8. The method for producing a stamper master for producing an optical recording medium according to claim 1, wherein the thin film is formed by sputtering or chemical plating. 9. The method according to claim 2, wherein said thin film is formed by sputtering or chemical plating. 10. The method according to claim 3, wherein said thin film is formed by sputtering or chemical plating.