JPH11238256A - Device and method for the production of optical record medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size of an optical disk while maintaining the recording capacity of the disk by making the outer diameter of the disk and the track pitch to be specific dimensions and forming a fine ruggedness pattern in a finer manner on at least one main surface of the disk substrate. SOLUTION: The pattern formed on a pattern mask plate 20 is reduced to a 1/4 size, for example, and reduction-projection exposed on a photoresist 31 of a substrate material 30. Then, 0.1 to 0.5 μm track pitches are formed on the material 30. Then, employing a similar method, fine reggedness having a 0.03 to 0.3 μm depth is formed. Then, a reflection film, a dielectric protection layer, a phase transition film and a dielectric protection layer are successively laminated in that order to form an information recording layer. Then, recording media having a 20 to 40 mm disk diameter are cut from the material 30. If the track pitch is set to 0.4 μm and the shortest pit length in the fine ruggendess is made to 0.2 μm, for example, the surface density becomes approximately 3.7 times, the areal ratio becomes 1/16 and the recording density is made to approximately 1 GB.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk type optical recording medium, a method for manufacturing the same, and an apparatus for manufacturing an optical recording medium used for the same.

[0002]

2. Description of the Related Art Conventionally, as a disk-type optical recording medium,
A so-called compact disk (hereinafter, simply referred to as a CD) may be used. This CD has a size of 12c in diameter.
m, a thickness of 1.2 mm, and is formed of a light-transmitting plastic substrate such as polycarbonate.

[0003] This CD has fine irregularities such as phase pits for recording data information, tracking servo signals, and the like. The track pitch of the pit row having the fine irregularities is about 1.6 μm, and the shortest pit length is about 0.83 μm.
By setting m, digital information having a capacity of 650 MB can be recorded on one main surface of the substrate. This CD
Is a portable music player (so-called CD player)
Alternatively, the recorded information can be reproduced by a CD drive or the like of a notebook personal computer.

The structure of a conventional single-layer optical disk and a method of manufacturing the same will be described below with reference to the drawings. As shown in FIG. 11, this optical disc is made of a light-transmitting resin such as polycarbonate, for example, having a diameter of 12 cm,
Fine irregularities 102 are formed on a substrate 101 having a thickness of 1.2 mm, a reflective film 103 is applied to the fine irregularities 102, an information recording layer 104 is formed, and the information recording layer 104 is further formed.
The protective film 105 is formed thereon.

An example of a method for forming the fine unevenness 102 will be described below. First, as shown in FIG. 12, a glass master 110 having a sufficiently smooth surface is placed on a rotating base 111, and is exposed on the glass master 110 while being rotated at a predetermined rotation speed. Photoresist which becomes alkali-soluble by so-called positive photoresist 11
3 is supplied from the nozzle 112 and applied.

[0006] Next, as shown in FIG.
10 is rotated, and the photoresist 113 is stretched.
As shown in FIG. 4, a state in which a photoresist layer is applied over the entire surface of the glass master 110 is set.

Next, as shown in FIG. 15, the recording laser light L modulated by the modulator M is applied to the objective lens 114.
The light is condensed on the photoresist 113, and the photoresist 113 is exposed in a predetermined pattern. This exposure is performed spirally at a constant track pitch by sending the recording laser beam at equal distances per rotation in the radial direction of the glass master 110 while rotating the glass master 110.

Next, the glass master 110 is developed with an alkaline developer to remove the exposed portions. In this case, FIG.
As shown in FIG. 6A and an enlarged view of FIG.
Then, a through hole is formed, and fine irregularities 115 are formed.

[0009] As shown in FIG.
After forming fine irregularities 115 having a predetermined pattern by the method 3, nickel plating 118 is applied on the glass master 110, and then the nickel plating 118 is peeled off.
As shown in FIG.
Is formed.

Thus, the information recording layer 104 formed on the substrate 101 constituting the optical recording medium shown in FIG.
A stamper for transferring the fine irregularities 103 constituting is formed.

The stamper 11 manufactured as described above
As shown in FIG. 19, the substrate 101 is injection-molded, or is pressed on a photo-curable resin formed on the substrate and exposed and cured by a 2P method (photo-polymerization method). Transfer of the fine irregularities of the stamper 119 is performed, and the stamper 119 is peeled off as shown in FIG.

Thereafter, as shown in FIG.
An information recording layer 104 is formed by laminating a reflective film of Al or the like on the substrate 02. Further, a protective film 105 is formed on the information recording layer 104 with a photocurable resin or the like, whereby a target optical recording medium can be manufactured.

[0013]

In recent years, there has been a demand for smaller and lighter portable information devices. With this, CD
Also, for a magneto-optical disk such as a so-called mini disk (hereinafter simply referred to as MD), which is capable of recording and reproducing information on the same disk-type recording medium as a CD, while maintaining the existing recording capacity, It is desired to reduce the size of the.

However, if the CD is made to be 1/4 of the conventional size, that is, an optical disc having a diameter of about 3 cm, while maintaining the existing recording capacity, that is, the digital information amount of 650 MB on one main surface of the substrate, the CD is assumed. It is necessary that the track pitch of the pit row having the fine irregularities is about 0.4 μm and the shortest pit length is about 0.21 μm.
It is difficult to form such a fine pit pattern by a conventional CD manufacturing apparatus. As for the MD and the like, similarly to the above, it is difficult to form a pattern of fine unevenness such as a groove for tracking guide at a track pitch of about 0.4 μm by a conventional MD manufacturing apparatus.

Therefore, in the present invention, an optical recording medium having a finer pattern of fine irregularities forming recording information or a tracking guide in order to realize a smaller optical disk while maintaining the capacity of the optical disk. And a method for manufacturing an optical recording medium and an apparatus for manufacturing an optical recording medium used in the method.

[0016]

An optical recording medium according to the present invention has an information recording layer having fine irregularities on at least one principal surface of a substrate, and records or reproduces information with the information recording layer. It is a disc-shaped optical recording medium that has an outer diameter of 20 to 40 mm and a track pitch of
It is assumed to be 0.1 to 0.5 μm.

The optical recording medium of the present invention is formed by forming a required pattern on a master by photolithography to form a pattern mask plate, applying a photoresist on a substrate material, and forming the pattern mask plate. Pattern 1
/ N (1 <n), and is manufactured by performing a reduced exposure for transferring onto a substrate material by photolithography.

An apparatus used for manufacturing the above-described optical recording medium of the present invention includes a light emitting device and a pattern in which light emitted from the light emitting device is formed on a master by forming a required pattern by photolithography. It is assumed that the apparatus has a light irradiation device for irradiating the mask plate and a reduction projection exposure device equipped with a reduction lens for reducing and projecting the pattern of the pattern mask plate onto the object to be exposed.

That is, in the present invention, a pattern of fine pits and grooves is formed finer by reduction exposure than in a conventional optical recording medium. Is manufactured.

Further, according to the present invention, the relative positional relationship between the condensing spot of the exposure light from the reduction projection apparatus of the reduction projection exposure apparatus and the substrate material is changed so that the predetermined position of the substrate material is Since a plurality of optical recording medium substrates can be manufactured by performing pattern exposure, a plurality of optical recording media are manufactured from a single substrate material.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical recording medium according to the present invention has at least one major surface of a substrate having fine irregularities of pits and grooves constituting an information recording layer of the optical recording medium. A disk-shaped optical recording medium on which information can be recorded or reproduced with a magnetic head or an optical head that is a combination of them, having an outer diameter of 20 to 40 mm and a track pitch of pits or grooves. , 0.1 to 0.5 μm.

In this optical recording medium, a step of forming a required pattern on a master by photolithography to form a pattern mask, reducing the pattern of the pattern mask to 1 / n, and forming a photomask on a substrate material It can be manufactured by a process of transferring by lithography.

In the following, a case will be described in which an optical disk on which information can be recorded, reproduced, and rewritten by light irradiation is obtained. However, the present invention is not limited to this example. It can be applied to various optical recording media. Hereinafter, the optical recording medium of the present invention and the method for producing the same will be described by way of example. However, the present invention is not limited to the optical recording medium and the method for producing the same.

In the following example, a disc-shaped disk having pits and grooves that constitute an information recording layer of an optical recording medium on one principal surface of a substrate and capable of recording or reproducing information is provided. An optical recording medium having an outer diameter of 30
mm, a thickness of 1.2 mm, and a track pitch of pits or grooves of 0.4 μm is manufactured. The diameter of the optical recording medium is 20 to 40 mm. The size can be appropriately manufactured, and the same various dimensions can be selected for the thickness of the optical recording medium. The present invention is limited to the case where an optical disc having the following dimensions is obtained. Not something. Also, the track pitch of the pits or grooves can be appropriately adjusted in the range of 0.1 to 0.5 μm depending on the reduction ratio in the reduction exposure step described below and the size of the track pitch to be projected. However, the present invention is not limited to the reduction magnification shown in FIG.

As shown in FIG. 1, a metal film 11 made of, for example, chromium is formed on a master disk 10 made of, for example, quartz glass, which is formed into a circle or a square. On the metal film 11, for example, a conventional CD (Compact D)
isc), DVD (Digital Versatil)
e Disc), the exposure wavelength of laser light emitted from a laser beam recorder applicable to the production of optical discs such as 413 nm, 351
photoresist 1 exposed to nm laser light
2 is formed.

As shown in FIG. 2, a predetermined wavelength, for example, 413 nm, 351 is output from the laser beam recorder 13.
The laser beam L _{1 of} nm is emitted, the direction of the laser beam L ₁ is adjusted by the mirror 14, and the laser beam L ₁ is condensed on the photoresist 12 by the objective lens 15. Is formed. Next, development is performed using, for example, an alkali developing solution to form the photoresist 12 in a predetermined pattern.

After a predetermined pattern is formed on the photoresist 12 as described above, the metal film 11 is etched using the photoresist pattern as a mask. Thereafter, the photoresist is removed, and a pattern mask plate 20 on which a metal film pattern 11a is formed is formed on the master 10 as shown in FIG. This metal film pattern 1
1a is formed in a radius of 24-58 mm of the master 10 with a track pitch of, for example, about 1.6 μm.

Next, the pattern of the pattern mask plate 20 is reduced to 1 / n by a reduction projection exposure apparatus, and is transferred by photolithography onto a substrate material which is a base material of an optical recording medium. FIG. 4 shows a schematic view of a reduction projection exposure apparatus 50 which is a main part of the optical recording medium manufacturing apparatus of the present invention. This reduction projection exposure apparatus 50 is, for example,
A light emitting device 21 for emitting a KrF excimer laser,
A light irradiation device 22 for irradiating the pattern mask plate 20 with the emitted laser light; A. Is comprised of a reduction projection device 23 equipped with a reduction lens (not shown) which is a lens having a field size of 30 mm in diameter, and a base 24 on which a substrate 30 as an object to be exposed is placed. The base 24 can be adjusted in either the surface direction or the normal direction of the base 24 so that the relative position between the pattern mask plate 20, the condensing spot of the exposure light, and the substrate material 30 can be adjusted. Being able to move.

The process of reducing the pattern of the pattern mask plate 20 using the reduction projection exposure apparatus 50 shown in FIG. 4 and transferring the pattern onto the substrate material by photolithography will be described below.

First, a disc-shaped substrate material 30 made of, for example, silicon having a diameter of, for example, 200 mm (8 inches) and a thickness of 0.5 to 2 mm, for example, 1.2 mm is placed on the substrate material 30 with respect to the wavelength of exposure light. A suitable photoresist 31 is uniformly applied to a thickness of, for example, about 0.1 μm.

Thereafter, the substrate 30 is placed on the base 24. The relative positional relationship between the substrate material 30 and the pattern mask plate 20 is adjusted by moving the base 24 in the vertical direction or the plane direction.

From the light emitting device 21, for example, the wavelength 248
A KrF excimer laser beam L ₂ of nm is emitted, and the pattern mask plate 20 is irradiated by the light irradiation device 22.

The laser beam L _{2 that} has passed through the pattern mask plate 20 on which a predetermined pattern has been formed is
The light is condensed on the substrate material 30 through 3. That is, the pattern formed on the pattern mask plate 20 is
A predetermined magnification, for example, ４, is applied to the upper photoresist 31.
And the image is exposed. Thus, 1
When the projection exposure is performed by reducing to / 4, the pattern mask plate 2
The track pitch of the predetermined pattern formed at 0 is 1.
When the thickness is about 6 μm, a fine pattern with a track pitch of about 0.4 μm can be formed on the substrate material 30.

Next, as shown in FIG. 5, the base 24 is moved in the plane direction of the substrate 30 to sequentially change the relative position between the condensing spot of the exposure light and the substrate 30.
The pattern formed on the pattern mask plate 20 is reduced to, for example, １ ／ on the photoresist 31 on the substrate material 30, and a plurality of patterns are sequentially projected and exposed. At this time, as described above, when a substrate for an optical disk having a diameter of, for example, 30 mm is manufactured from the substrate material 30 having a diameter of 200 mm, about 19 projections can be made, for example.

As described above, after exposing the photoresist 31, development is performed using, for example, an alkali developing solution, and a predetermined pattern is formed by the photoresist 31 as shown in FIG.

Next, as shown in FIG. 7, dry etching is performed using the photoresist pattern as a mask.
A pattern of fine irregularities 32 having a desired depth, for example, a depth of 0.03 to 0.3 μm is formed on the substrate material 30, and then the photoresist 31 is removed. Thereby, for example, the diameter 2
A plurality of substrates of an optical recording medium having a diameter of, for example, 30 mm are formed on a substrate material 30 of silicon having a thickness of 00 mm.

Next, as shown in FIG. 8, a material film 40 applied to a recordable / reproducible optical disk containing a phase change material is sequentially laminated on fine irregularities 32 formed on a substrate material 30 to obtain information. The recording layer 70 is formed. The material film 40 includes the reflection film 33, the first dielectric protection layer 34, and the phase change film 3 shown in FIG.
5, the second dielectric protection layer 36 is used. That is, the reflection film 33 such as Al,
First dielectric protection layer 34, for example, ZnS—SiO ₂ , phase change film 35, for example, GeSbTe, second dielectric protection film 36
For example, the information recording layer 70 of the optical recording medium is formed by laminating, for example, ZnS—SiO ₂ by sputtering.

Next, as shown in FIG. 9, a protective film 37 is formed on the material film 40 by, for example, a liquid photocurable resin to protect the material film 40, and a high N.I. A. To a thickness suitable for the recording / reproducing optical pickup of, for example, 50 μm.

Next, as shown in FIG.
An optical recording medium 60 having a diameter of 30 mm is cut out from a silicon substrate material 30 of 00 mm. After that, the end face of the optical recording medium is processed, the side face is smoothed, and finally a small-sized phase-change optical disc with a diameter of 30 mm, which can be recorded and reproduced, can be produced. The recording or reproduction of the optical recording medium thus manufactured is performed through the protective film 37 at a high N.V. A. Of the optical pickup.

The recording capacity of the optical disk which can be recorded and reproduced as described above is set to DVD-RAM (R
The comparison is made based on an Random Access Memory. The DVD-RAM is an optical disk having a GeSbTe-based phase change film and capable of recording and reproducing with a red semiconductor laser having a wavelength of 650 nm. This DVD
-The RAM has a capacity of 2.6 GB on a disk with a diameter of 120 mm.
Record information is stored. The track pitch is 0.74 μm, and it has a configuration in which information can be recorded on both lands and grooves having fine irregularities constituting an information recording portion. The shortest mark length is 0.61 μm. The wavelength λ of the laser beam of the optical pickup is 650 nm, and the numerical aperture N.P. A. Is 0.6, and the focused spot size on the optical disc is λ / N. A. Approximate to 1.08 μm.

On the other hand, in the case of the optical recording medium of the present invention in the above-described embodiment, which is a phase-change type optical disk, if it is configured to be recordable on both lands and grooves in the same manner as a DVD-RAM, a track The pitch is approx.
2 μm. Further, the wavelength of the optical pickup which will be realized in the future can be shortened, and the N.I. A. For example, the wavelength λ of the laser light of the optical pickup is set to 400 nm, A. Is 0.90, the focused spot size is 0.44 μm. Assuming that the shortest mark length is simply reduced by the size ratio from the DVD-RAM mark length, the shortest mark length is 0.25 μm.

As described above, when the track pitch and the shortest mark length are compared with the conventional one, the optical disc of the present invention in the above-described embodiment has an area density about 9.1 times as large as that of the DVD-RAM. become. The optical disk of the present invention in the above-described embodiment has a diameter of 30 m.
m, which is 1/4 that of the conventional optical disk, and therefore the area ratio is 1/16. From this,
The recording capacity of the optical disk of the present invention in the above-described embodiment is [2.6 (GB) × 9.1] / 16 = about 1.5 (G
B).

On the other hand, for a read-only optical disk,
Conventional DVD-ROM (Read Only Memory)
Compare with y). A DVD-ROM is an optical disk that can be reproduced by a red semiconductor laser having a wavelength of 650 nm. This DVD-ROM has a track pitch of 0.74 μm and a minimum pit length of 0.4 μm.
And has a recording capacity of 4.7 GB on a disk having a diameter of 120 mm.

In the optical disk according to the embodiment of the present invention, the track pitch is 0.4 μm and the shortest pit length is 0.1 μm.
Since it can be formed to a thickness of 2 μm, it has a surface density about 3.7 times that of a DVD-ROM. Also,
The optical disk of the present invention in the above-described embodiment has a diameter of 3
0 mm, which is 1/4 of the size of the conventional optical disk, so that the area ratio is 1/16. From this, the recording capacity of the optical disk of the present invention in the above-described embodiment is [4.7 (GB) × 3.7] / 16 = about 1 (G
B).

As described above, in this embodiment of the present invention, it is possible to obtain an optical disk having a recording capacity of 1.5 GB capable of recording and reproduction and an optical disk having a recording capacity of 1 GB dedicated to reproduction.

In the above-described embodiment, the laser beam L ₂ passing through the pattern mask plate 20 on which a predetermined pattern is formed is focused on the substrate material 30 via the reduction projection device 23, and Although the case where the reduced projection of the pattern formed on the substrate 20 is performed has been described, the present invention is not limited to this example, and the phase shift mask technology that is being put into practical use in semiconductor lithography, for example, the Levenson type phase shift system Is applied, reduction projection exposure of a finer pattern can be performed. That is, the present invention can be applied to a case where the pattern mask plate 20 and the phase shift mask on which a predetermined pattern is formed are stacked and reduced exposure is performed by using this. In this case, light interference by the phase shift mask can be used, and due to this effect, the reduced projection of the pattern miniaturized by about 以下 or less compared to the case of using only the pattern mask plate 20 of the above embodiment. Exposure becomes possible. That is, in the above-described embodiment, the track pitch is set to 0.1 μm to 0.2 μm.
It can be about μm. Thereby, the pits and grooves forming the information recording layer of the conventional optical recording medium can be formed with finer irregularities, so that a smaller optical recording medium can be obtained while maintaining the conventional recording capacity. be able to.

In the above-described embodiment, as shown in FIG. 9, a so-called configuration in which a material film 40 containing a phase-change material is formed in a pattern of fine irregularities formed on a substrate constituting an optical recording medium. The case where an optical recording medium capable of recording and reproduction is obtained has been described. However, the present invention is not limited to this example, and the pits constituting the recording information are formed in advance as the fine irregularities described above, and Al or the like is formed thereon. It is also applicable to the case of obtaining a so-called read-only optical disk having a structure in which a reflective film is formed by vapor-depositing a metal of the present invention, and the recording capacity of a conventional optical recording medium is retained as in the above-described embodiment. As it is, a small optical recording medium can be manufactured. In this case, in the conventional optical disk, the shortest pit length is formed to be about 0.8 μm. Therefore, the shortest pit length is reduced to about ４ by performing the reduced projection exposure of the present embodiment of the present invention. And can be formed to a thickness of about 0.2 μm.

Further, the optical recording medium of the present invention is not limited to the case where a phase change material is formed as a material film,
By forming a magneto-optical material film such as a GdFeCo-based material or a PtCo-based material, the present invention can also be applied to a case where a magneto-optical disc capable of recording and reproduction is manufactured.

In the above-described embodiment, the case where an optical recording medium having a so-called single-layer structure in which one information recording layer having fine irregularities is formed has been described. However, the present invention is not limited to this embodiment. However, the present invention can be applied to a case where an optical recording medium having a multilayer structure in which two or more substrates that can be manufactured by the method of the present invention are laminated is manufactured.

In the above-described embodiment, a photoresist 31 is applied on a silicon substrate
After reducing and exposing a predetermined pattern on the top, the pattern is developed to form fine irregularities of a predetermined pattern, a material film 40 is formed on the fine irregularities, and a protective film 37 is formed on the material film 40. Although the case where the optical disk is formed and then cut out to a required size from the silicon substrate material 30 to finally produce a target small optical disk has been described, the present invention
It is not limited to this example.

That is, in the above-described embodiment, as described with reference to FIGS. 4 and 5, after a predetermined pattern is reduced and exposed on the substrate material 30, development is performed as shown in FIG. Etching is performed as shown in FIG.
Is formed, a nickel stamper is formed on the fine irregularities 32 formed on the substrate material 30 by, for example, nickel plating, and light of polycarbonate or the like is formed using the stamper having the predetermined pattern formed thereon. Injection molding of transparent resin and photo-polymerization method
The present invention can also be applied to a case where fine irregularities of a predetermined pattern are transferred by the P method, and thereafter, the optical recording medium is cut out and manufactured by the same method as described above. Also in this case, similarly to the above-described embodiment, the pits and grooves forming the information recording layer of the conventional optical recording medium can be formed with finer irregularities, so that the conventional recording capacity can be maintained. Thus, a smaller optical recording medium can be obtained.

In the above embodiment, silicon was used as the material of the substrate constituting the optical recording medium. However, the present invention is not limited to this example, and glass, Al,
Organic resins such as metal materials such as Cu and Ni and various plastics such as polycarbonate can be similarly applied.

[0053]

According to the optical recording medium of the present invention and the method of manufacturing the optical recording medium of the present invention, it is possible to form a fine uneven pattern constituting an information recording layer of an optical recording medium by performing reduced exposure. As a result, it was possible to form the optical recording medium more finely, thereby making it possible to manufacture a small-sized optical recording medium while securing the recording capacity of the conventional optical recording medium.

According to the optical recording medium of the present invention and the method of manufacturing an optical recording medium using the apparatus for manufacturing an optical recording medium of the present invention, an optical disk smaller than a conventional optical disk can be obtained. Thus, it was possible to reduce deformation such as warpage, thereby reducing surface deflection due to rotation, and performing stable reproduction or recording of information. In addition, since the optical disk could be downsized, the portable information device could be further downsized, downsized, and lightened.

Further, according to the method of manufacturing an optical recording medium of the present invention, by changing the relative positional relationship between the exposure light spot and the substrate material on one substrate material, the pattern Exposure can be performed to manufacture a substrate for a large number of optical recording media, so that the manufacturing process of the optical recording medium can be facilitated, thereby improving the productivity of the optical recording medium. Was.

[Brief description of the drawings]

FIG. 1 shows a manufacturing process diagram of an optical recording medium according to an example of the present invention.

FIG. 2 shows a manufacturing process diagram of an optical recording medium according to an example of the present invention.

FIG. 3 shows a manufacturing process diagram of an optical recording medium according to an example of the present invention.

FIG. 4 is a schematic view of a reduction projection exposure apparatus applied to manufacture of an optical recording medium according to an example of the present invention.

FIG. 5 is a schematic view showing a state in which reduction projection exposure is sequentially performed.

FIG. 6 shows a manufacturing process diagram of an optical recording medium according to an example of the present invention.

FIG. 7 shows a manufacturing process diagram of an optical recording medium according to an example of the present invention.

FIG. 8 shows a manufacturing process diagram of an optical recording medium according to an example of the present invention.

FIG. 9 shows a manufacturing process diagram of an optical recording medium according to an example of the present invention.

FIG. 10 is a schematic view showing a state where an optical recording medium according to an example of the present invention is cut out from a substrate material.

FIG. 11 is a schematic cross-sectional view of a conventional optical recording medium having a single-layer structure.

FIG. 12 is a view showing a manufacturing process of an optical recording medium master.

FIG. 13 shows a manufacturing process diagram of an optical recording medium master.

FIG. 14 shows a manufacturing process diagram of an optical recording medium master.

FIG. 15 shows a manufacturing process diagram of an original master of an optical recording medium.

FIG. 16 is a schematic perspective view of a master after exposure. B shows an enlarged view of fine irregularities formed on the master after exposure.

FIG. 17 is a schematic cross-sectional view showing a state where nickel plating has been applied to a master after exposure.

FIG. 18 shows a schematic sectional view of a stamper.

FIG. 19 shows a state diagram in which fine irregularities are transferred to a substrate of an optical recording medium by a stamper.

FIG. 20 is a schematic sectional view of a substrate on which fine irregularities have been transferred by a stamper.

[Explanation of symbols]

10 master, 11 metal film, 12 photoresist, 1
3 ... laser beam recorder, 14 ... mirror, 15 ...
Objective lens, 11a: metal film pattern, 20: pattern mask plate, 21: light emitting device, 22: light irradiation device, 23
... reduction projection device, 24 ... base, 30 ... substrate material, 31 ... photoresist, 32 ... fine irregularities, 33 ... reflection film, 34 ...
First dielectric protection layer, 35: phase change film, 36: second dielectric protection layer, 37: protection film, 40: material film, 50: reduction projection exposure apparatus, 60: optical recording medium, 70: information Recording layer, 101: substrate, 102: fine irregularities, 103: reflective film, 104: information recording layer, 105: protective film, 110: glass master, 111: rotating base, 112: nozzle, 113
... photoresist, 114 ... objective lens, 115 ... fine unevenness, 118 ... nickel plating, 119 ... stamper,
125 ... fine irregularities

Claims (7)

[Claims] 1. A disc-shaped optical recording medium in which an information recording layer having fine irregularities is formed on at least one principal surface of a substrate, and information can be recorded or reproduced by the information recording layer. An optical recording medium having an outer diameter of 20 to 40 mm and a track pitch of 0.1 to 0.5 μm. 2. A step of forming a required pattern on a master by photolithography to form a pattern mask plate; a step of applying a photoresist on a substrate material; and a step of forming a pattern on the pattern mask plate. To 1 / n
A reduction exposure step of reducing the image to (1 <n) and transferring the image onto a substrate material by photolithography. 3. A light emitting device, a light irradiating device for irradiating a light emitted from the light emitting device onto a pattern mask plate having a required pattern formed on a master by photolithography, and a pattern on the pattern mask plate An optical recording medium manufacturing apparatus, comprising: a reduction projection exposure apparatus equipped with a reduction lens for reducing and projecting an image onto an object to be exposed. 4. The method according to claim 2, wherein a phase shift mask is laminated on the pattern mask plate, and the reduction exposure step is performed. 5. The method for manufacturing an optical recording medium according to claim 2, wherein n is n = 4. 6. The method according to claim 1, further comprising: after the reduction exposure step, developing a photoresist on the substrate material and performing patterning by etching, and forming a material film on the substrate material. The method for producing an optical recording medium according to claim 2, wherein 7. After the reduction exposure step, a step of developing a photoresist on the substrate material and performing patterning by etching, a step of applying nickel plating on the substrate material, and removing the nickel plating to form a stamper 3. The method for manufacturing an optical recording medium according to claim 2, comprising a step of forming and a step of transferring a pattern formed on the stamper to a light-transmitting resin.