JP2009205748A - Method of manufacturing optical disk master disk, and method of manufacturing optical disk using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form an optical disk master disk having a fine uneven shape by using an exposure device using a laser beam. <P>SOLUTION: A method of manufacturing the optical disk master disk includes a resist film forming step of forming a resist film 2 composed of a transition metal oxide of an amorphous structure on a substrate 1, an exposure step of performing exposure to the resist film 2 with the laser beam, a development step of developing the exposed resist film 2 by an alkaline developer to form a resist pattern 4 of a projecting and recessed shape and an etching step of performing etching to the substrate by using the resist pattern 4 as a mask to form an etching pattern 5 of a projecting and recessed shape. The resist film 2 is composed of the transition metal oxide containing at least an oxide of tungsten and an exposure part exposed in the exposure step is changed into a transition metal oxide of a developer soluble crystal structure from a transition metal oxide of a developer insoluble amorphous structure and the exposure part is removed by the developer in the development step and the resist pattern 4 is formed from the resist film 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of manufacturing an optical disc master having a high recording density and an optical disc manufacturing method using the same.

In recent years, with the start of digital high-definition broadcasting and the appearance of full-high-definition video equipment, the next-generation DVD (Digital Versatile Disc) standard capable of recording and playing back high-definition video has been established. -Two types of optical discs, DVD (High Definition-Digital Versatile Disc), have been put on the market. These optical disks have a recording capacity of 3 to 5 times that of a DVD, while the diameter is 12 cm, which is the same as that of a DVD.
The next-generation DVD has an increased recording capacity compared to the DVD, which is because the pits and grooves, which are uneven shapes formed on the transparent substrate, are miniaturized.

  When manufacturing such a next-generation DVD, an optical disk master manufacturing method for forming fine pits and grooves of the next-generation DVD using an exposure apparatus for manufacturing a conventional DVD optical disk master, and using the same A method for manufacturing an optical disk is described in Patent Document 1.

Patent Document 1 generally describes as follows.
First, an intermediate layer made of amorphous silicon is uniformly formed with a thickness of 80 nm on a silicon substrate by sputtering.
Next, an inorganic resist layer made of an inorganic resist material, which is an incomplete oxide of a transition metal, is uniformly formed with a thickness of 55 nm on the formed intermediate layer.
Next, a laser according to an input signal pattern is applied to an inorganic resist layer using an exposure apparatus including a laser device having a laser wavelength of 405 nm and an objective lens having a numerical aperture NA of 0.95, which is used for manufacturing an existing DVD. Light is selectively exposed to light.
Further, by developing the exposed inorganic resist layer, an optical disc master having a concavo-convex shape corresponding to an input signal pattern with a track pitch of 0.32 μm is obtained.

A known technique is used in the process of forming the optical disk from the optical disk master.
First, a metallic nickel film was deposited on the concavo-convex shape surface of the optical disc master by electroforming, and after the deposited metal nickel film was peeled off from the optical disc master, a predetermined processing was performed, and the concavo-convex shape of the optical disc master was transferred. Get a stamper.
Using this stamper, an optical disk substrate made of polycarbonate which is a thermoplastic resin is molded by an injection molding method.
Next, a reflective film made of an Al alloy or the like is formed on the irregular surface of the molded optical disk substrate, and a protective film having a thickness of about 0.1 mm is further applied on the reflective film to obtain an optical disk.

  Here, tungsten or the like is used as the transition metal, and the oxidation state of the transition metal is an incomplete oxide state that is less than the oxygen content of the stoichiometric composition according to the valence that the transition metal can take.

JP 2004-152465 A

By the way, a video apparatus capable of displaying a video having a resolution four times as high as that of a full high-definition image having a resolution of 4K × 2K has been developed.
In order to supply video to such a video device, the need for a high-density optical disk with a larger recording capacity than BD and HD-DVD has increased in order to record and play back higher-definition video than full HD. . Such a high-density optical disk needs to have finer pits and grooves than BD and HD-DVD.
In particular, with respect to the increase in the density of the optical disk in the circumferential direction, a slight improvement can be expected in the reduction of the pit length by examining the modulation method. In this manufacturing method, since the numerical aperture of the objective lens used for exposure is high and the thickness of the inorganic resist layer is thick, it is difficult to form an uneven shape with a track pitch narrower than the BD track pitch of 0.32 μm. .

  In addition, the optical disc master described in Patent Document 1 has unevenness corresponding to a signal pattern made of an inorganic resist layer on a glass substrate by developing the inorganic resist layer with selective exposure corresponding to the signal pattern. A shape is formed. Since the numerical aperture NA of the optical system used at the time of exposure is as large as 0.95, in the case of the optical disc master described in Patent Document 1 where the thickness of the inorganic resist layer is as thick as 55 nm, the uneven side wall portion occupying the track pitch It was difficult to narrow the track pitch because of the large proportion of the inclined area.

In addition, the inorganic resist layer described in Patent Document 1 is a transition metal non-stoichiometric oxide, and is in a state in which oxygen is deficient as compared with an oxide having a stoichiometric composition.
Therefore, when light, heat, or the like is applied to the inorganic resist layer, the oxidation is promoted and the oxidation state changes. As the exposure conditions change accordingly, stable exposure may not be possible.
In addition, since the optical disc master described in Patent Document 1 has a concavo-convex shape formed from a transition metal oxide deviating from the stoichiometric composition, it is chemically unstable and difficult to store in the state of the optical disc master. Met.

  Further, the depth of the concavo-convex groove formed on the optical disc master described in Patent Document 1 is determined by the film thickness of the inorganic resist layer. Therefore, when the groove depth of the concavo-convex shape is increased, the thickness of the resist layer is increased and the inclined region of the side wall portion is increased, so that the track pitch is increased accordingly. Therefore, the concave and convex groove depth cannot be arbitrarily changed.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of an optical disk master which can manufacture easily the optical disk original disk and optical disk which can record a higher density than BD and HD-DVD using the conventional DVD exposure equipment, and its use An object of the present invention is to provide a method for manufacturing an optical disc.
It is another object of the present invention to provide a method of manufacturing an optical disc master and a method of manufacturing an optical disc using the same, which can narrow the track pitch by making the formed uneven side wall portion less inclined and nearly vertical.
Also provided are a method for producing an optical disc master that does not contain a transition metal oxide deviating from the stoichiometric composition as a material for the optical disc master, and has a reduced surface roughness, and a method for producing an optical disc using the same. With the goal.
It is another object of the present invention to provide a method of manufacturing an optical disc master and a method of manufacturing an optical disc using the same, in which the depth of the concavo-convex groove formed on the optical disc master can be arbitrarily changed.

In order to achieve the above object, the present invention has the following procedures 1) to 6).
1) In the method of manufacturing the optical disk master 6, a resist film forming step for forming a resist film 2 made of a transition metal oxide having an amorphous structure on the substrate 1, and a laser for the resist film 2 formed on the substrate 1 An exposure step of exposing with light, a development step of developing the exposed resist film 2 with an alkaline developer to form a concavo-convex resist pattern 4, and etching the substrate using the developed resist pattern 4 as a mask The resist film 2 is a transition metal oxide containing at least an oxide of tungsten, and the resist film 2 was exposed by the exposure process. The exposed portion becomes a transition metal oxide having a soluble crystal structure from an amorphous transition metal oxide insoluble in the developer, The image process, the exposed portions are removed with a developer, the manufacturing method of the optical disc master, characterized in that the resist film 2 resist pattern 4 is formed.
2) The method for producing an optical disc master according to 1), wherein the etching step uses a fluorocarbon-based gas as an etching gas.
3) The method for producing an optical disc master according to 1) or 2), further comprising an ashing step of performing ashing and trimming using a fluorocarbon-based gas after the etching step.
4) Using the optical disc master 6 having the concavo-convex etching pattern 5 produced by the method for manufacturing an optical disc master according to any one of 1) to 3), the stamper 7 having the concavo-convex shape transferred thereon is formed. Using the formed stamper 7, forming a transparent substrate 8 having a concavo-convex shape using a transparent resin as a raw material, forming a reflective layer on the formed transparent substrate 8, A method for producing an optical disc, comprising: forming a reflective layer 9 on a shape, and forming a reflective layer.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of an optical disk master and the manufacture of an optical disk using the same which can manufacture easily the optical disk master and optical disk of higher density than BD and HD-DVD using the conventional DVD exposure equipment Can provide a method.
Further, it is possible to provide a method of manufacturing an optical disc master having a small inclination of the formed uneven side wall and a narrow track pitch, and a method of manufacturing an optical disc using the same.
Further, it is possible to provide a method of manufacturing an optical disc master that does not include a transition metal oxide deviating from the stoichiometric composition as a material of the optical disc master and has a reduced surface roughness, and a method of manufacturing an optical disc using the same.
In addition, it is possible to provide a method of manufacturing an optical disc master and a method of manufacturing an optical disc using the same, which can arbitrarily change the depth of the concave and convex grooves formed on the optical disc master.

Embodiments of an optical disk master manufacturing method and an optical disk manufacturing method using the same according to the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view of a substrate used for manufacturing an optical disc master according to the present invention. FIG. 2 is a manufacturing process diagram showing a method of manufacturing an optical disc master according to the present invention. FIG. 3 is a cross-sectional view showing a latent image pattern in the optical disc master according to the present invention. FIG. 4 is a manufacturing process diagram showing an optical disk manufacturing method using the optical disk master according to the present invention. FIG. 5 is a cross-sectional photograph of the SEM showing the uneven shape of the optical disc master according to the present invention.
2 and 4 show a manufacturing process of a method of manufacturing an optical disk master and a method of manufacturing an optical disk using the same when a disk-shaped substrate is cut along the AA 'section as shown in FIG. FIG.
Note that components having common functions are denoted by the same reference symbols throughout the drawings, and repeated descriptions of components once described are omitted.

First, the manufacturing process of the optical disc master will be described with reference to FIGS.
(Resist film formation process)
As shown in FIG. 2A, an inorganic resist film 2 having a thickness of 10 nm to 30 nm is formed by magnetron sputtering or the like on a disc-shaped substrate 1 that has been optically polished, washed, and sufficiently dried. The film thickness of the inorganic resist film 2 is about half of the film thickness (55 nm) of the conventional inorganic resist.
As the substrate 1, a quartz glass substrate or a silicon wafer substrate can be used.
In particular, silicon wafer substrates are used in the semiconductor field and can be obtained in a sufficiently polished and cleaned state. The surface is smoother and more clean than quartz glass. This is preferable because it is not necessary to separately form a conductive film when the stamper is manufactured.

(Latent image forming process)
Next, as shown in FIG. 2B, laser light having a wavelength of about 400 nm as used in an existing exposure apparatus such as a DVD is applied to the inorganic resist film 2 formed on the substrate 1 with a numerical aperture NA. Is condensed by an objective lens having a value of about 0.9, and exposure is performed based on an input information signal to form a desired latent image pattern 3.
As shown in FIG. 3, the cross section of the latent image pattern 3 in the disk radial direction of the disk-shaped substrate 1 is an upper portion 101 on the laser beam incident side based on the cone angle shape of the laser beam condensed by the objective lens. It has an inverted trapezoidal shape that is wide on the side and narrow on the side of the lower part 102 that is the interface with the substrate 1.
Therefore, as the numerical aperture of the objective lens increases, the cone angle also increases, and the angle C1 formed by the lower portion 102 of the latent image pattern 3 and the side surface 103 of the latent image pattern 3 decreases. As a result, the non-exposed trapezoidal non-exposed region 104 of the inorganic resist film 2 becomes small, and in some cases, the adjacent latent image patterns 3 may be connected.

  In the present invention, since the thickness of the inorganic resist film 2 is 10 nm to 30 nm, which is thinner than 55 nm of the conventional example, the exposure sensitivity is higher than the conventional example, and the width of the upper width 101 and the lower portion 102 is set to the track pitch of BD It can be made narrower than 0.32 μm.

(Resist pattern formation process)
Next, as shown in FIG. 2C, the latent image pattern 3 formed on the inorganic resist film 2 on the substrate 1 is developed to remove the latent image pattern 3 and form a resist pattern 4.
The resist pattern 4 has an inverted trapezoidal cross section with respect to the disk radial direction of the disk-shaped substrate 1 based on the latent image pattern 3, and the lower portion 102 that is an interface with the substrate 1 has a narrow width. .
Here, an alkaline developer that is alkaline is used as the developer used in the development.

As the inorganic resist film 2, an oxide of tungsten (W) having high exposure sensitivity with laser light is used.
WO ₂ which is a kind of oxide of tungsten (W) is stable at room temperature and becomes WO ₃ when heated.
WO ₂ formed by the sputtering method has an amorphous structure, and is heated by being exposed to laser light to become WO ₃ having a crystal structure, so that it becomes soluble in an alkaline solution used as a developer.
Further, when MoO ₂ which is an oxide of molybdenum (Mo) is added to WO ₂ , the exposure sensitivity is lowered, but the disturbance of the shape of the side surface 103 of the latent image pattern 3 shown in FIG. 3 can be reduced.
As a result, a fine latent image pattern 3 with a narrow track pitch can be formed by making the film thickness of the inorganic resist film 2 of WO ₂ formed by sputtering thinner than 10 nm to 30 nm, which is 55 nm of the conventional example. By adding MoO ₂ to WO ₂ , the disturbance of the shape of the latent image pattern 3 can be reduced.

(Etching process)
Next, as shown in FIG. 2D, an etching pattern 5 is directly formed on the substrate 1 by dry etching the exposed portion of the substrate 1 using the resist pattern 4 formed on the substrate 1 as a mask.
By using a fluorocarbon gas such as CF ₄ , CHF ₃ , C ₃ F ₈ , or C ₄ F ₈ as an etching gas, the etching rate of the substrate 1 can be greatly increased with respect to the resist pattern 4. It can be a big etching.
The shape of the etching pattern 5 is a shape corresponding to the width of the lower portion 102 of the latent image pattern 3 shown in FIG. 3 which is the interface between the resist pattern 4 and the substrate 1.

In particular, etching using CHF ₃ as a fluorocarbon-based gas can perform anisotropic etching in which the etching rate in the downward direction in FIG. 2D is larger than the etching rate in the left-right direction. The cross-sectional shape of the etching pattern 5 in the disk radial direction of the substrate 1 is nearly rectangular, and the side surface of the concavo-convex shape is substantially orthogonal to the plate surface of the disk-shaped substrate 1.
Furthermore, since the concavo-convex shape is formed by etching, the depth of the concavo-convex shape, which has been conventionally defined by the film thickness of the resist film, can be controlled by the etching conditions, and deep grooves can be formed.

(Ashing process)
Next, as shown in FIG. 2E, the resist pattern 4 formed on the substrate 1 is isotropically resisted by applying a voltage in a fluorocarbon-based gas atmosphere using a fluorocarbon-based gas. Pattern ashing and trimming are performed to remove the resist pattern mask 4 and reduce the roughness of the surface, thereby obtaining a disc-shaped optical disc master 6 having an etching pattern 5 based on an input information signal.
Here, CF ₄ , CHF ₃ , C ₃ F ₈ , C ₄ F ₈ or the like is used as the fluorocarbon-based gas. In particular, CF ₄ is suitable as an etching gas because it is easy to perform isotropic etching.

The disc-shaped optical disc master 6 formed from the substrate 1 made of disc-shaped quartz glass or silicon wafer in this way has an etching pattern 5 having a narrow track pitch and a small track shape.
Further, since the optical disc master 6 is composed only of the constituent material of the substrate 1, the shape of the etching pattern 5 does not change even when left for a long time.
Furthermore, the groove depth of the etching pattern 5 can be adjusted by optimizing the etching conditions.

Next, a process for manufacturing an optical disk from the disk-shaped optical disk master 6 formed by the above procedure will be described with reference to FIG.
(Stamper fabrication process)
As shown in FIG. 4A, after a Ni film having a thickness of 50 to 200 nm is formed by sputtering on the surface of the disk-shaped optical disk master 6 on which the concavo-convex shape is formed, the thickness is increased by electroforming. By forming a Ni plating film having a thickness of 100 to 500 μm, the etching pattern 5 formed on the optical disc master 6 is transferred to produce a disc-shaped stamper 7 having a concavo-convex shape.
The uneven shape formed on the stamper 7 has an uneven relationship with the etching pattern 5 formed on the optical disc master 6.

(Transparent substrate manufacturing process)
Next, as shown in FIG. 4B, a disc-shaped stamper 7 having an uneven shape is mounted on an injection molding machine (not shown), and from the inner periphery to the outer periphery, or by the injection molding method. A disk-shaped transparent substrate 8 having a concavo-convex shape in which grooves or pits based on an input information signal are spirally formed from the outer periphery toward the inner periphery is formed.

(Reflective layer formation process)
Next, as shown in FIG. 4C, a metal reflective layer 9 having a predetermined thickness is formed on the surface of the transparent substrate 8 on the side where the grooves or pits are formed by sputtering or vacuum deposition.
Here, as a material for forming the metal reflection layer 9, a metal element such as Au, Ag, and Al, which has a high reflectance at the wavelength of the signal readout laser beam, and a compound thereof are used.

(Protective layer formation process)
Next, as shown in FIG. 4D, an ultraviolet curable resin is applied to the side of the transparent substrate 8 on which the metal reflective layer 9 is formed, and then the transparent substrate 8 coated with the ultraviolet curable resin is rotated. After leveling the ultraviolet curable resin, the protective layer 10 is formed by irradiating the ultraviolet ray to cure the ultraviolet curable resin.
The optical disc 11 is formed through the above steps.

Hereinafter, the present invention will be described in detail with specific examples, but the present invention is not limited to the following examples without departing from the gist thereof.
(Example)
As shown in FIG. 2 (A), the quartz glass substrate 1 that has been subjected to surface polishing, washed and dried is subjected to magnetron sputtering using an alloy target of tungsten (W) and molybdenum (Mo). Reactive sputtering was performed by introducing 44 sccm of argon and 6 sccm of oxygen. Here, the composition ratio of the alloy of W and Mo was 9: 1 (wt%).

An amorphous inorganic resist film 2 made of a transition metal oxide WO ₂ and MoO ₂ having a thickness of 20 nm was formed by reactive sputtering using an alloy target of W and Mo.
The ultimate vacuum at this time was 2 × 10 ⁻⁶ Torr, and the vacuum during film formation was 2.7 × 10 ⁻³ Torr.

Next, as shown in FIG. 2B, an exposure apparatus having a semiconductor laser with a wavelength of 405 nm and an objective lens with NA = 0.90 is applied to the amorphous inorganic resist film 2 formed on the quartz glass substrate 1. And a line-and-space-shaped latent image pattern in which exposure is performed at a linear velocity of 3.5 m / s, and a uniform pattern of lines and valleys with a track pitch of 0.20 μm is continuous. 3 was formed.
The region of the exposed latent image pattern 3 of the amorphous inorganic resist film 2 made of WO ₂ and MoO ₂ is crystallized and changed to WO ₃ and MoO ₂ .

Next, as shown in FIG. 2C, the latent image pattern 3 made of WO ₃ and MoO ₂ formed on the quartz glass substrate 1 was developed.
For the development, an alkaline tetramethylammonium hydroxide solution (concentration: 2.38 wt%) is used as a developing solution, and the quartz glass substrate 1 on which the latent image pattern 3 is formed is immersed at room temperature for 20 minutes. Then, a resist pattern 4 was formed.

Next, as shown in FIG. 2D, dry etching is performed on the exposed portion of the quartz glass substrate 1 using CHF ₃ gas using the resist pattern 4 formed on the quartz glass substrate 1 as a mask. It was.
Dry etching was performed by applying a power of 100 W for 6 minutes in an atmosphere of 4 Pa in order to increase anisotropy, and an etching pattern 5 having a line and space shape was formed on the quartz glass substrate 1. The etching pattern was 180 nm deep, the groove width was 100 nm, and the aspect ratio of the etching pattern 5 was 1.8: 1 at the bottom surface of the etching pattern 5.
In addition, since the resist pattern 4 serving as a mask is as thin as 20 nm, most of the resist pattern 4 is also removed by dry etching with CHF ₃ gas.

Next, as shown in FIG. 2E, ashing was performed on the etching pattern 5 formed on the quartz glass substrate 1 using CF ₄ gas.
Ashing the mixing ratio 5 of CF ₄ and 0 _2: done by applying a power of 30mW under an atmosphere of 15Pa using 2 gas, and at the same time to remove the resist pattern 4, the surface of the quartz glass substrate Roughening was reduced.
As a result, an optical disc master 6 having the etching pattern 5 shown in FIG. 5 was formed.

Next, as shown in FIG. 3A, after a Ni film having a thickness of 50 to 200 nm is formed on the optical disk master 6 by sputtering, an Ni plating film having a thickness of 100 to 500 μm is formed by electroforming. As a result, the stamper 7 was manufactured by transferring the etching pattern 5 formed on the optical disc master 6.
The pattern formed on the stamper 7 has a reverse relationship to the etching pattern 5 formed on the optical disc master 6.

Next, as shown in FIG. 3B, the stamper 7 is mounted on an injection molding machine (not shown), and a spiral line and space shape is formed from the inner periphery toward the outer periphery by an injection molding method. The formed transparent substrate 8 was molded.
The formed transparent substrate 8 had a thickness of 1.1 mm, a track pitch of 0.2 μm, a depth of 180 nm, and a groove width of 100 nm.

Next, as shown in FIG. 3C, a metal reflective layer 8 made of an Al alloy having a thickness of 30 nm was formed on the transparent substrate 8 by sputtering or vacuum deposition.
Finally, as shown in FIG. 3D, a protective layer 10 having a film thickness of 100 μm is formed by applying an ultraviolet curable resin on the metal reflective layer 8 by spin coating and curing it by irradiating with ultraviolet rays. As a result, an optical disk 11 was obtained.

(Reproduction characteristic evaluation)
The optical disk 11 produced by the above-described method is rotated at a linear velocity of 3.0 m / sec, and an optical disk reproduction evaluation machine equipped with a semiconductor laser having an oscillation wavelength of 405 nm and an objective lens having a numerical aperture of 0.85 is used. Evaluation was performed.
As a result of inspection by an optical disk reproduction evaluation machine, the noise level was -65 db.

(Comparative example)
As a comparative example, an optical disc having the same track pitch (0.32 μm) as that of a Blu-ray disc was produced using a conventional technique, and the reproduction characteristics were evaluated.
The reproduction characteristics were evaluated by rotating at a linear velocity of 3.0 m / sec using an optical disk reproduction evaluator equipped with a semiconductor laser having an oscillation wavelength of 405 nm and an objective lens having a numerical aperture of 0.85, as in the example. Was measured.
As a result of the inspection by the optical disk reproduction evaluation machine, the noise level was −45 db, and the noise level could be reduced by this example.
This is because the aspect ratio of the line and space shape formed in the example is high, and the roughness of the surface of the line and space shape is reduced by trimming in the ashing process.

As described above, according to the optical disk master manufacturing method and the optical disk manufacturing method using the same according to the present invention, an existing exposure apparatus using a semiconductor laser having a wavelength of 405 nm as a light source for exposure is used and the thickness is as thin as 20 nm. By performing exposure using a transition metal oxide having a film thickness as a resist film, a line-and-space-shaped resist pattern 4 having a track pitch of 0.2 μm (conventional example 0.32 μm) is formed on the substrate 1. be able to.
Further, by using the resist pattern 4 on the substrate 1 and performing isotropic etching using a fluorocarbon-based gas as an etching gas, the groove depth is 180 nm (conventional example 55 nm) and the groove width is 100 nm (conventional example 160 nm). ), An optical disc master 6 having an etching pattern 5 having a high aspect ratio such that the aspect ratio is 1.8: 1 can be formed.
Further, the surface roughness of the etching pattern 5 can be reduced by subjecting the surface of the etching pattern 5 formed on the optical disc master 6 to an ashing process and a trimming process using a fluorocarbon-based gas as an etching gas. 6 can form the optical disk 11 having a low noise level during reproduction.

In this embodiment, the ashing process is performed to improve the surface property of the optical disk master, but the ashing process can be omitted depending on the conditions of the etching process.
In the present embodiment, the method for manufacturing the read-only optical disc has been described. Needless to say, a recordable optical disc can be obtained by forming at least a recording film between the transparent substrate and the reflective film. .

It is a perspective view of the board | substrate used for manufacture of the optical disk master concerning this invention. It is a manufacturing process figure which shows the manufacturing method of the optical disk original disk which concerns on this invention. It is sectional drawing which shows the latent image pattern in the optical disk original disc based on this invention. It is a manufacturing process figure which shows the manufacturing method of the optical disk using the optical disk original disc based on this invention. It is a cross-sectional photograph of SEM which shows the uneven | corrugated shape of the optical disk original disk which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Substrate (quartz glass substrate), 2 ... Inorganic resist film, 3 ... Latent image pattern, 4 ... Resist pattern, 5 ... Etching pattern, 6 ... Master optical disc, 7 ... Stamper, 8 ... Transparent substrate, 9 ... Metal reflective layer , 11: optical disk, 101: upper part of the latent image pattern, 102: lower part of the latent image pattern, 103: side part of the latent image pattern, 104: unexposed part,

Claims (4)

In the method of manufacturing an optical disc master,
A resist film forming step of forming a resist film made of an amorphous transition metal oxide on the substrate;
An exposure step of exposing the resist film formed on the substrate with a laser beam;
Developing the exposed resist film with an alkaline developer to form a concavo-convex resist pattern; and
Etching the substrate using the developed resist pattern as a mask to form an uneven etching pattern; and
Have
The resist film is a transition metal oxide containing at least an oxide of tungsten,
By the exposure step, the exposed exposed portion in the resist film becomes a transition metal oxide having a soluble crystal structure from the transition metal oxide having an amorphous structure insoluble in the developer,
The method of manufacturing an optical disc master, wherein the developing step removes the exposed portion with the developer and forms the resist pattern from the resist film.   2. The method of manufacturing an optical disc master according to claim 1, wherein the etching step uses a fluorocarbon-based gas as an etching gas.   3. The method of manufacturing an optical disc master according to claim 1, further comprising an ashing step of performing ashing and trimming using a fluorocarbon-based gas after the etching step. A stamper for forming a stamper, to which the concavo-convex shape is transferred, using the optical disc master having the concavo-convex-shaped etching pattern produced by the method for manufacturing an optical disc master according to any one of claims 1 to 3. Creation process,
Using the formed stamper, a transparent substrate manufacturing step of forming a transparent substrate having the uneven shape using a transparent resin as a raw material;
A reflective layer forming step of forming a reflective layer on the formed transparent substrate and forming a reflective layer on the irregular shape; and
A method for manufacturing an optical disk, comprising: forming an optical disk.

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