JP2001243662A - Method of manufacturing recording medium, and method of manufacturing master disk for manufacture of recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently increase the adhesion property of a photosensitive material layer in the formation of a fine rugged pattern and to suppress increase in the number of production processes therefor in a method of manufacturing a recording medium having a fine rugged pattern and in a method of manufacturing a master disk for the manufacture of a recording medium. SOLUTION: In the method of manufacturing a recording medium having the fine rugged pattern in the process of patterning by pattern exposure and development of a photosensitive material layer, a base layer 4 which improves the adhesion property of the photosensitive material layer 5 and which shows solubility with the developer for the development of the photosensitive material layer is formed on the structural substrate 1 of the recording medium, and then the photosensitive layer is formed on the base layer. Thus, the base layer is patterned at the same time of developing the photosensitive material after the pattern exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a recording medium suitable for obtaining a recording medium having fine irregularities such as recording marks or track grooves, and a method for manufacturing a master for manufacturing a recording medium. Get involved. In the present invention, the master is a stamper for molding a recording medium having fine irregularities by, for example, injection molding or a 2P method (Photopolymerization method), or a so-called master for copying and copying a plurality of stampers. , Including a so-called mother master for transferring and copying a plurality of masters.

[0002]

2. Description of the Related Art In recent years, toward realization of higher recording density, an optical system in an optical pickup for performing optical recording and / or optical reproduction has been increased in numerical aperture (high NA), and optical recording and optical recording have been performed. Attempts have been made to shorten the wavelength of laser light for optical reproduction, that is, to reduce the beam spot diameter using so-called blue-violet laser light. Along with this, the necessity of making finer and finer pitches of fine uneven patterns such as recording marks and track grooves on a recording medium is increasing.

[0003] As a method of manufacturing a recording medium having a fine concavo-convex pattern, for example, an optical disk, a recording medium having a target fine concavo-convex pattern by forming fine concavo-convex directly on a substrate constituting the recording medium, or There is a method of producing a master for producing a recording medium having fine irregularities, for example, a stamper, and obtaining a recording medium having the desired fine irregularities by injection molding or 2P method.

In any of these methods, in forming fine irregularities on a substrate constituting a recording medium or a substrate constituting a master, a photosensitive material layer is used to perform exposure and development steps on the photosensitive material layer. Fabrication of a pattern corresponding to the target fine uneven pattern by the material layer is performed.

[0005] That is, for example, a glass substrate having a smooth surface is prepared, a photosensitive material layer is applied to the glass substrate, pattern exposure corresponding to the desired fine irregularities is performed, and development processing is performed. By patterning, for example, fine concavities and convexities corresponding to fine concavities and convexities on a target recording medium are formed by this pattern. Then, on the patterned photosensitive material layer, for example, a Ni plating layer by electroless plating and electroplating is formed so as to embed the pattern, and this plating layer is formed from the substrate having the photosensitive material layer. By peeling off, a stamper, master or mother master for forming a recording medium is manufactured. A stamper formed by the Ni plating layer formed in this manner,
Alternatively, as described above, the recording medium having the desired fine irregularities is produced by injection molding or the 2P method using a stamper obtained by producing a replica by a master or a mother master.

[0006]

However, as described above, when the fine concavo-convex pattern formed by the photosensitive material layer is further miniaturized, a problem occurs in the adhesion to the substrate, and the finely patterned photosensitive material is formed. Peeling and flow occur in the layer,
It inhibits the formation of high-density, high-precision fine irregularities and increases the incidence of defective products.

In order to increase the adhesion of the photosensitive material layer to the substrate, a method has been proposed in which a Cr layer is deposited on the substrate by sputtering or the like, and the photosensitive material layer is applied thereon. However, in this case, a step of etching the Cr layer using the photosensitive material layer as a mask after exposure and development of the photosensitive material layer is required. This will hinder the formation of irregularities.

In some cases, a recording medium requires particularly high flatness. That is, as described above,
In a near-field configuration, or in a case where an optical lens is mounted on, for example, an air slider and a distance between the slider member and a recording medium is set to 100 nm or less, for example, as recently proposed. The recording media require high surface flatness. However, as described above, in forming a stamper or the like,
Forming the plating layer depends on the plating speed depending on the surface shape, position, and the like. Therefore, some undulation tends to occur in this plating layer, that is, the stamper. This is a problem in producing a recording medium having a field configuration and a slider configuration.

As a method for improving the flatness of a recording medium, RIE is applied to the surface of the master disk regardless of the plating method.
There is a method by which fine irregularities having a required pattern are formed by (reactive ion etching) (for example, JP-A-6-212458). According to this method, there is an advantage that the depth and the cross-sectional shape of the fine unevenness do not depend on the photosensitive material layer.

However, even in this case, the RI
There is a problem of the adhesion of the photosensitive material layer as the mask of E. When Cr is used as the underlayer to increase the adhesion, the same problem as described above occurs.
For example, depending on the RIE gas type for the glass master, RI
Since E cannot be performed, a patterning step of Cr is required prior to this RIE, and the number of steps is increased.

Further, as described above, when fine irregularities are formed by the photosensitive material layer, the height difference of the fine irregularities in the finally obtained recording medium is regulated by the thickness of the photosensitive material layer. In addition, there is an undesirable restriction that the cross-sectional shape also depends on the cross-sectional shape of the fine unevenness formed on the photosensitive material layer. However, as described above, using the pattern of the photosensitive material layer as a mask,
When fine unevenness is formed by E, there is also an advantage that such a restriction is eliminated.

In the present invention, in the method for producing a recording medium having fine irregularities and the method for producing a master for producing a recording medium, the adhesiveness of the photosensitive material layer at least in the formation of the fine irregularities is sufficiently increased, and An increase in the number of manufacturing steps is suppressed.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a method for manufacturing a recording medium having fine irregularities through a patterning step by pattern exposure and development of a photosensitive material layer, and comprises a structure of the recording medium. On the substrate, a step of improving the adhesiveness of the photosensitive material layer and forming a base layer showing solubility in a developing solution of a developing process for the photosensitive material layer, for example, an aluminum Al layer or a silicon Si layer described later. A step of forming a photosensitive material layer on the underlayer, a step of pattern exposure corresponding to fine irregularities on the photosensitive material layer, a patterning of the photosensitive material layer with a developer, and a photosensitivity by the patterning. A development step is performed in which patterning for dissolving the underlayer through the openings in the material layer is performed simultaneously.

The present invention also relates to a method for producing a recording medium producing master for producing a recording medium having fine irregularities through a patterning step by pattern exposure and development of a photosensitive material layer. Forming a base layer that improves the adhesion of the photosensitive material layer and is soluble in a developing solution in a developing process for the photosensitive material layer; and forming a photosensitive material layer on the base layer. And, a pattern exposure step according to the fine irregularities on the photosensitive material layer, and patterning of the photosensitive material layer by a developer,
And a developing step of simultaneously performing patterning for dissolving the underlying layer through the opening of the photosensitive material layer by the patterning.

A method for manufacturing a recording medium according to the present invention,
In the method of manufacturing a master for producing a recording medium, a base layer is provided to enhance the adhesiveness of the photosensitive material layer to prevent the separation and the flow of the photosensitive material layer. By configuring the layer with a material layer that can be dissolved by the developer of the layer, this special work for patterning the underlayer is avoided. That is, even though an underlayer is provided to increase the adhesion of the photosensitive material layer, an increase in the number of steps due to separate patterning of the underlayer is avoided.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the method for manufacturing a recording medium according to the present invention is a method for manufacturing a recording medium having fine irregularities through a patterning step of pattern exposure and development of a photosensitive material layer. In the method, on the constituent substrate of the recording medium, the adhesiveness of the photosensitive material layer is improved, and the solubility of the photosensitive material layer in a developing solution of a developing process is reduced, for example, by using Al or Al as a main component. It is formed as a ground layer, and a photosensitive material layer is formed thereon.

Then, the photosensitive material layer is subjected to pattern exposure according to the fine irregularities on the finally obtained recording medium, and thereafter, the photosensitive material layer is subjected to a developing treatment with a developing solution. A development process is performed to remove the exposed or unexposed portions of the layer. In this manner, in the photosensitive material layer, a pattern corresponding to the above-described fine pattern, that is, a fine pattern having an opening of the same pattern as the concave and convex portions of the fine unevenness in the finally obtained recording medium or an inverted pattern of this pattern is formed. I do. At this time, since the underlayer is dissolved by the developing solution, the underlayer is removed in the same pattern as the opening of the photosensitive material layer at the same time as the development processing of the photosensitive material layer, and the photosensitive material layer is removed. An opening having the same pattern as the pattern is formed.

Further, the method of manufacturing a master for producing a recording medium according to the present invention is a method of manufacturing a master for producing a recording medium for producing a recording medium having fine irregularities through a patterning step by pattern exposure and development of a photosensitive material layer. In the above, on the constituent substrate of the master, an adhesive layer of a photosensitive material layer is improved, and the photosensitive material layer is soluble in a developing solution of a developing process, for example, Al or an underlayer containing Al as a main component. Is formed, and a photosensitive material layer is formed on the underlayer.

Thereafter, the photosensitive material layer is subjected to pattern exposure in accordance with fine irregularities, and is subjected to a developing treatment with a developing solution, whereby patterning of the photosensitive material layer and opening of the photosensitive material layer by the patterning are performed. Patterning for dissolving the underlayer is performed simultaneously. That is, openings having the same pattern are formed in the photosensitive material layer and the underlayer.

In the above-described method for producing a recording medium and the method for producing a master for producing a recording medium, the photosensitive material layer uses, for example, a photosensitive material of a novolak resin, and the developing solution is
Tetramethylammonium hydroxide can be used, and this developer is Al or
, Ie, the underlayer described above can be dissolved. Here, the material containing Al as a main component refers to another material, for example, 1 as long as it enhances the function as the above-described underlayer, that is, the adhesiveness of the photosensitive material layer and does not impair the property of being dissolved by the developer. By adding Ti, Si, etc. to about 2% by volume, a composition can be obtained which prevents crystallization during the formation of this underlayer and obtains flatness.

The underlayer, which enhances the adhesion of the photosensitive material layer and can be dissolved by the developer of the photosensitive material layer, is not limited to Al or a material mainly composed of Al. For example, it can be made of Si or a material mainly composed of Si.

First, an example of a method of manufacturing a recording medium for obtaining an optical disk, in which at least one of recording and reproduction is optically performed, such as a recording medium according to the present invention, for example, a magneto-optical recording medium, a phase change recording medium, or the like, will be described. The process will be described with reference to schematic cross-sectional views of each process in the process chart of FIG. 1 (part 1) and the process chart of FIG. 2 (part 2). FIG. 3 shows a flowchart of this manufacturing method. First, as shown in FIG. 1A, a transparent substrate 1 constituting a recording medium, for example, an SiO ₂ substrate is prepared, and the surface of the SiO ₂ substrate is cleaned. This substrate 1
For example, on a glass substrate 2, a material layer 3 of SiO ₂ , that is, a material layer 3 capable of forming a concave portion by RIE described later.
May be formed on the SiO ₂ substrate.

On the cleaning surface of the substrate 1, a film of the underlayer 4 made of Al, for example, a film is formed by sputtering.
The thickness of the Al underlayer 4 is accompanied by so-called fringing in which the light distribution of the exposure spot does not become monomodal due to metal reflection upon exposure to the photosensitive material layer described later and a small peak of the light distribution occurs at the edge. A thickness of 1 nm to 2 nm that does not cause inconvenience such as air leaking and that has an effect of improving the adhesion between the photosensitive material layer formed thereon and the substrate 1. It is desirable that

Next, as shown in FIG. 1B, a resist, that is, a photosensitive material layer 5 is applied on the underlayer 4. The photosensitive material layer 5 is formed by applying a photosensitive material such as a positive type novolak resin by a spin coating method or the like.

The photosensitive material layer 5 is subjected to pattern exposure to form an exposed part 6 as shown in FIG. 1C.
In this exposure, the substrate 1 is transparent and the underlayer is 1 nm.
By selecting about 2 nm, a decrease in exposure accuracy due to unnecessary reflection can be avoided. In this exposure, for example, a concave portion in the finally obtained fine unevenness, for example, a formation portion such as a track guide groove or a pit of a recording mark, is exposed, and this exposed portion 6 is made soluble.

The photosensitive material layer 5 thus pattern-exposed is developed. In this developing process, the photosensitive material is immersed in a developing solution so as to dissolve the exposed area. When the photosensitive material layer 5 is a novolak resin, tetramethylammonium hydroxide can be used as the developer. By doing so, the photosensitive material layer 5
1D, an opening 5A is formed in the exposed portion 6, and since the developer can dissolve Al, the opening of the photosensitive material layer 5 is also formed for the underlying layer 4 made of Al. The underlying layer 4 exposed to the outside through 5A is also dissolved and etched to form an opening 4A having a pattern corresponding to the pattern of the opening 5A.

In this case, an Al underlayer 4 is formed on the photosensitive material layer 5, and this Al is made of SiO _{2 as a} substrate material.
In addition, since the adhesiveness to the photosensitive material layer 5 is good and the adhesiveness of the photosensitive material layer 5 to the substrate 1 is enhanced, the developing process for the photosensitive material layer 5, that is, the developing solution Also, the immersion in the photosensitive material layer 5 does not cause flow or peeling in the photosensitive material layer 5.

Next, as shown in FIG. 2A, using the photosensitive material layer 5 as a mask, anisotropic etching of the SiO ₂ material layer 3 of the substrate 1 through the opening 5A and the opening 4A of the underlayer 4 can be performed. The concave portion 7 is formed by performing etching. This etching is performed by RIE (reactive ion etching) using a gas such as CF ₄ or CHF ₃ .

As described above, the SiO _{2 is formed} by RIE.
A concave portion 7 corresponding to the openings 5A and 4B in the material layer 3;
In other portions, the convex portions 8 left without being subjected to RIE are formed, and the concave portions 7 and the convex portions 8 form the target fine unevenness 9 such as a track guide groove or a pit of a recording mark. As described above, when the fine irregularities 9 are formed by etching, for example, RIE, generation of undulation as described at the beginning can be avoided because the plating process is not performed.

Thereafter, the photosensitive material layer 5 is peeled off by the peeling solution. Further, as a finally obtained recording medium, A
If it is not preferable for the recording or reproduction or the like to remain, the Al underlayer 4 is peeled off using, for example, an alkaline solution.

As shown in FIG. 2C, a recording film such as a magneto-optical recording film, a phase change recording film, a dielectric film, a metal reflection film, and a heat diffusion film is formed on the substrate 1 on which the fine unevenness 9 is formed. Recording medium constituent film 10 corresponding to the target recording medium such as
The recording medium 1 is formed by performing, for example, a magneto-optical recording, a phase change recording, etc.
2. For example, configure an optical disk.

The recording medium 12 thus manufactured
Has excellent flatness in which undulation is avoided by avoiding the plating step. Further, the depth and the cross-sectional shape of the fine unevenness are not restricted by the thickness and the cross-sectional shape of the photosensitive material layer. Also, the flow and peeling of the photosensitive material layer are avoided. Therefore, according to the method for manufacturing a recording medium, a recording medium in which very fine and fine irregularities due to a narrow pitch are surely formed in, for example, high-density recording in which recording and / or reproduction is performed using a short-wavelength blue-violet laser beam is provided. It can be manufactured with good yield.
Further, by improving the waviness, high reliability can be obtained as a near-field configuration or a recording medium using an optical lens at a distance of, for example, 100 nm or less from a recording medium mounted on a slider.

Next, an example in which the present invention is applied to a method of manufacturing a master for manufacturing a recording medium will be described with reference to FIGS. 4A to 4C (first manufacturing process), FIGS. 3 will be described with reference to schematic cross-sectional views of each step of the manufacturing process diagram (No. 3). FIG. 7 shows a flowchart of this manufacturing method. First,
As shown in FIG. 4A, a transparent substrate 21 constituting a master, for example, a stamper is prepared, and the substrate surface is cleaned. This substrate 2
1 also, for example, on a glass substrate 22, R
Material layer 23 of SiO ₂ capable of forming recesses by IE
Can be formed on the SiO ₂ substrate.

Also in this case, FIGS.
D, steps similar to those described in FIGS. 2A and 2B are employed. That is, on the cleaning surface of the substrate 21, the underlayer 4 is formed from Al, for example, by sputtering. Also in this case, as described above, the thickness of the Al underlayer 4 has the effect of preventing inconvenience due to metal reflection upon exposure of the photosensitive material layer described later and improving the adhesion to the substrate 21. It is desirable that the thickness be 1 nm to 2 nm, which can be played.

Next, as shown in FIG. 4B, a resist, that is, a photosensitive material layer 5 is applied on the underlayer 4. The photosensitive material layer 5 is formed by applying a photosensitive material such as a positive type novolak resin by a spin coating method or the like.

The photosensitive material layer 5 is subjected to pattern exposure to form an exposed portion 6 as shown in FIG. 4C.
In this exposure, for example, a portion other than a convex portion in the finally obtained fine unevenness, for example, a track guide groove, a pit of a recording mark, or the like is exposed to make the exposed portion 6 soluble.

The photosensitive material layer 5 thus pattern-exposed is developed. In this developing process, the photosensitive material is immersed in a developing solution so as to dissolve the exposed area. When the photosensitive material layer 5 is a novolak resin, tetramethylammonium hydroxide can be used as the developer. By doing so, the photosensitive material layer 5
As shown in FIG. 4D, an opening 5A is formed in the exposed portion 6, and since this developer can dissolve the Al, the opening of the photosensitive material layer 5 is also formed for the underlying layer 4 made of Al. The underlying layer 4 exposed to the outside through 5A is also dissolved and etched to form an opening 4A having a pattern corresponding to the pattern of the opening 5A.

In this case, an Al underlayer 4 is formed on the photosensitive material layer 5, and this Al is made of SiO ₂ of the substrate material.
In addition, since the adhesiveness to the photosensitive material layer 5 is good and the adhesiveness of the photosensitive material layer 5 to the substrate 1 is enhanced, the developing process for the photosensitive material layer 5, that is, the developing solution Also, the immersion in the photosensitive material layer 5 does not cause flow or peeling in the photosensitive material layer 5.

Next, as shown in FIG. 5A, using the photosensitive material layer 5 as a mask, anisotropic etching is performed on the SiO ₂ material layer 3 of the substrate 1 through the opening 5A and the opening 4A of the base layer 4. Etching is performed to make the recess 27
Is formed. This etching is performed by RIE (reactive ion etching) using a gas such as CF ₄ or CHF ₃ .

As described above, the SiO ₂ was formed by RIE.
In the material layer 3, concave portions 27 corresponding to the openings 5A and 4B are provided.
In other portions, the convex portions 28 left without being subjected to RIE are formed, and the concave portions 27 and the convex portions 2 are formed.
8, the fine unevenness 29 is formed.

Thereafter, the photosensitive material layer 5 is peeled off by the peeling solution. Further, as a finally obtained recording medium, A
If it is not preferable for the recording or reproduction or the like to remain, the Al underlayer 4 is peeled off using, for example, an alkaline solution. In this way, as shown in FIG. 5B, a master 30 having fine irregularities 29, for example, a stamper for obtaining a target recording medium is manufactured. When the fine irregularities 29 are formed by etching, for example, RIE, the master 30 thus formed does not depend on the plating step, and therefore, generation of the undulation as described at the beginning can be avoided. Further, the depth and the cross-sectional shape of the fine unevenness are not restricted by the thickness and the cross-sectional shape of the photosensitive material layer.

Using the master thus manufactured as a stamper, the fine irregularities 9 obtained by inverting the fine irregularities 29 described above are formed by injection molding of a well-known molding method or 2P method as shown in FIG. 6A. The substrate 1 constituting the formed recording medium is configured.

As shown in FIG. 6B, a recording film such as a magneto-optical recording film, a phase change recording film, a dielectric film, a metal reflection film, and a heat diffusion film are formed on the substrate 1 on which the fine irregularities 9 are formed. Recording medium constituent film 10 corresponding to the target recording medium such as
The recording medium 1 is formed by performing, for example, a magneto-optical recording, a phase change recording, etc.
2. For example, configure an optical disk.

The recording medium 12 manufactured in this manner also has excellent flatness in which undulation is avoided because the plating step is avoided. Further, the depth and the cross-sectional shape of the fine unevenness are not restricted by the thickness and the cross-sectional shape of the photosensitive material layer. Also, the flow and peeling of the photosensitive material layer are avoided. Therefore, in the recording medium obtained by using this master for producing a recording medium, for example, extremely fine and minute irregularities due to a narrow pitch are surely formed in high-density recording in which recording is performed by using a short-wavelength blue-violet laser beam and / or reproduction is performed. The manufactured recording medium can be manufactured with good yield. Further, by improving the undulation, the distance between the near-field configuration described above and the recording medium in which the optical lens is mounted on the slider is set to, for example, 10 mm.
High reliability can be obtained as a recording medium used at 0 nm or less.

In the above-described example, a description has been given of the production of a recording medium or a master for molding a recording medium which is required to have no undulation such as a so-called near-field configuration. In the production of a recording medium on which recording and reproduction are not performed and a master for obtaining the recording medium, the present invention is not limited to the RIE process, and a plating method can be applied.

An example of this case will be described with reference to the process chart of FIG. 8 (part 1), the process chart of FIG. 9 (part 2), and the flowchart of FIG. In this example, a master for manufacturing a recording medium, in this example, for example, a master (hereinafter, referred to as a first master), a stamper by transferring the master (hereinafter, referred to as a second master), and a recording medium manufactured therewith. is there.

In this case, as shown in FIG. 8A, a substrate constituting the first master, for example, a glass substrate 31, is prepared, and after the cleaning step as described in FIG. 4, as shown in FIGS. Then, the same steps as those described with reference to FIGS.
8A to 8D, parts corresponding to FIGS. 4A to 4D are denoted by the same reference numerals, and redundant description will be omitted.

However, in this example, FIG.
As shown in (1), fine irregularities are formed by the photosensitive material layer 5. That is, the opening 5A from which the photosensitive material layer 5 has been removed.
For example, a concave portion 37 corresponding to a concave portion of a finally obtained recording medium is formed, and a first master 51 having fine irregularities 39 in which a convex portion 38 is formed by a portion where the photosensitive material layer 5 is left is formed. Make it.

Also in this case, the underlayer 4 is formed by dissolving the photosensitive material layer 5 of, for example, a novolak resin with a developer of a photosensitive material, for example, tetramethylammonium hydroxide, as described above. That is, simultaneously with the development processing on the photosensitive material layer 5, the Al layer of the base layer 4 is dissolved through the opening 5A to form the opening 4A. In this case as well, the thickness of the underlayer 4 is, for example, 1 which does not hinder the exposure processing on the photosensitive material layer 5 as described above.
It can be constituted by an Al layer having a thickness of 2 nm to 2 nm.

Then, the first master 51 on which the fine irregularities 39 are formed is used as a master to manufacture a second master, that is, a stamper. That is, FIG.
As shown in FIG.
For example, a Ni plating layer 40 is formed by electroless plating and electroplating so as to have a thickness for embedding.

As shown in FIG. 9B, the plating layer 40
Is peeled off from the first master 51 to obtain a second master 52, that is, a stamper, on which the fine irregularities 49 formed by transferring the fine irregularities 39 formed by the plating layer 40 are formed.

As shown in FIG. 9C, the fine irregularities 49 of the second master 52 are transferred by using a second master 52, ie, a stamper, by a known molding method such as injection molding or 2P method. The substrate 1 constituting the recording medium having the obtained fine irregularities 9 is obtained.

A recording film such as a magneto-optical recording film, a phase change recording film, a dielectric film, a metal reflection film, a heat diffusion A film forming step of the recording medium constituting film 10 corresponding to the target recording medium, such as a film, and the application of the protective layer 11 or the like to perform the target recording medium 12 such as magneto-optical recording, phase change recording, etc. Configure an optical disk.

Also in this method, the formation of the underlayer 4 for improving the adhesion of the photosensitive material layer 5 makes it difficult for the photosensitive material layer 5 to peel off. Therefore, the formation of the fine irregularities 39 can be surely formed as the fine irregularities of the high-density recording, whereby the fine irregularities 49 of the second master 52 manufactured by the first master 51 can also be reduced. It can be reliably formed as fine irregularities for high-density recording. Therefore, the fine irregularities 9 of the recording medium 12 obtained by molding can be surely formed as fine irregularities for high-density recording.

As described above, according to the method of manufacturing a recording medium and the method of manufacturing a master for manufacturing a recording medium of the present invention,
It is possible to reduce the probability of occurrence of errors in the recording medium due to uncertainties such as flow of the pattern of the photosensitive material layer and peeling. That is, the occurrence rate of defective products can be reduced.

In each of the above-described examples, the recording medium 12 obtained is subjected to optical recording, by irradiation of short-wavelength laser light, for example, blue-violet laser light from the substrate side or from the transparent protective layer 11 side. Light regeneration is performed. Therefore, the fine unevenness actually refers to a concave portion and a convex portion relatively.

In each of the above examples, the underlayer 4 is made of Al or a material containing Al as a main component. However, the present invention is not limited to this example. The developer may be made of another material that can be dissolved by, for example, tetramethylammonium hydroxide, for example, Si or a material containing Si as a main component.

Further, for example, a substrate 1 constituting a recording medium,
Alternatively, the surface of the substrate 21 forming the master is
_{Even when 2} O ₃ , SiN, TiO ₂ , Ta ₂ O ₅ or the like is formed, the above-described underlayer 4 can be applied.

Further, the photosensitive material layer 5 is not limited to a positive type structure which becomes soluble by exposure, and for example, a negative type photosensitive material layer can be used.

In the above-described example of the master for producing a recording medium, the stamper and the master for obtaining the stamper are used. However, the present invention is also applicable to a case where the master is obtained as a mother master for obtaining a master master. The method of the present invention is not limited to the examples described above, and various modifications can be made to the steps and the like.

The recording medium to which the present invention is applied can be various recording media such as a recordable / reproducible recording medium or a read-only recording medium such as a ROM (Read Only Memory) type optical disk and a magnetic disk. The present invention can be applied to a recording medium having a configuration.

[0062]

As described above, in the method of manufacturing a recording medium and the method of manufacturing a master for manufacturing a recording medium according to the present invention, the photosensitive material layer 5 may be made of, for example, Al or a base layer mainly composed of Al. By forming 4,
Since the adhesion of the photosensitive material layer 5 is enhanced, the flow of the pattern of the photosensitive material layer and the occurrence of peeling can be effectively avoided. Even when a stamper is transferred and manufactured from a master having fine irregularities due to the above, fine irregularities can be surely formed.

Therefore, even in the formation of high-density fine irregularities, the probability of occurrence of errors due to the pattern of the photosensitive material layer can be reduced, and the yield can be improved, that is, the incidence of defective products can be reduced. Can be.

Although the formation of the underlayer is performed, the patterning of the underlayer, that is, the formation of the openings can be performed simultaneously with the development of the photosensitive material layer. It is possible to avoid a remarkable increase in the number of steps as in the above.

Further, as described above, the depth and the cross-sectional shape of the fine unevenness are determined by forming the fine unevenness on the substrate by RIE, for example, by avoiding the plating step, for example, by RIE. , High-density fine irregularities can be formed with high precision.
Further, when this plating step is avoided, generation of undulation due to plating can be avoided, so that higher-density fine unevenness can be formed with higher precision. Further, by being able to avoid undulation, the distance between an optical system in a near-field configuration, a slider configuration, or the like, or a slider member and a recording medium is 200 nm or less, for example,
Even when the thickness is set to 0 nm or less, optical recording or optical reproduction can be performed without any trouble.

[Brief description of the drawings]

FIGS. 1A to 1D are process diagrams (part 1) showing schematic cross-sectional views in each process of an example of a method for manufacturing a recording medium according to the present invention.

FIGS. 2A to 2C are process diagrams (part 2) showing schematic cross-sectional views in each process of an example of a method for manufacturing a recording medium according to the present invention.

FIG. 3 is a flowchart of a method for manufacturing the recording medium according to the present invention shown in FIGS. 1 and 2.

FIGS. 4A to 4D are process diagrams (part 1) showing schematic cross-sectional views in respective steps of an example of a recording medium manufacturing master and a method of manufacturing a recording medium according to the present invention.

FIGS. 5A to 5C are process diagrams (part 2) showing schematic cross-sectional views in respective steps of an example of a recording medium manufacturing master and a method for manufacturing a recording medium according to the present invention.

FIGS. 6A and 6B are process diagrams (part 3) showing schematic cross-sectional views in each process of an example of a method for manufacturing a master for recording media and a recording medium according to the present invention.

FIG. 7 is a flowchart of the manufacturing method of the present invention shown in FIGS. 4 to 6;

FIGS. 8A to 8D are process diagrams (part 1) showing schematic cross-sectional views in respective steps of an example of a recording medium manufacturing master and a method of manufacturing a recording medium according to the present invention.

FIGS. 9A to 9D are process diagrams (part 2) showing schematic cross-sectional views in respective steps of an example of a recording medium manufacturing master and a method of manufacturing a recording medium according to the present invention.

FIG. 10 is a flowchart of the manufacturing method of the present invention shown in FIGS. 8 and 9;

[Explanation of symbols]

1,21,31 ... substrate, 2,22 ... substrate, 3
23: Material layer, 4: Underlayer, 5: Photosensitive material layer, 6: Exposure part, 7, 27, 37: Concave part,
8, 28: convex portion, 9, 29, 39, 49: fine unevenness, 10: recording medium constituent film, 11: protective layer,
12: recording medium, 30: master

Claims (13)

[Claims] 1. A method for producing a recording medium having fine irregularities through a patterning step of pattern exposure and development processing on a photosensitive material layer, wherein the photosensitive material layer is provided on a constituent substrate of the recording medium. Improving the adhesion of the material layer, forming a base layer showing solubility in the developing solution of the developing process for the photosensitive material layer, a step of forming a photosensitive material layer on the base layer, A pattern exposure step according to the fine irregularities for the photosensitive material layer, patterning of the photosensitive material layer by the developer, and patterning of dissolving the underlayer through the opening of the photosensitive material layer by the patterning. And a developing step of simultaneously performing the steps (a) to (c). 2. The method according to claim 1, wherein the underlayer is made of a material layer containing aluminum as a main component. 3. The method according to claim 1, wherein the underlayer comprises a material layer containing silicon as a main component. 4. The method according to claim 1, wherein the developer is an aqueous solution containing tetramethylammonium hydroxide as a main component. 5. The method for manufacturing a recording medium according to claim 1, further comprising a step of performing pattern etching on a constituent substrate of the recording medium using the patterned underlayer and the photosensitive material layer as a mask. A method for manufacturing a recording medium, comprising: 6. The method according to claim 5, wherein the pattern etching of the constituent substrate of the recording medium is performed by reactive ion etching. 7. A method of manufacturing a master for manufacturing a recording medium for manufacturing a recording medium having fine irregularities through a patterning step by pattern exposure and development processing on a photosensitive material layer, comprising: A step of improving the adhesion of the photosensitive material layer and forming a base layer showing solubility in the developing solution of the development processing for the photosensitive material layer; and forming a photosensitive material layer on the base layer. Pattern exposure step for the photosensitive material layer according to the fine irregularities; patterning of the photosensitive material layer by the developer; and dissolving the underlayer through the opening of the photosensitive material layer by the patterning. And a developing step of performing patterning at the same time. 8. The method according to claim 7, wherein the underlayer is made of a material layer containing aluminum as a main component. 9. The method according to claim 7, wherein the underlayer comprises a material layer containing silicon as a main component. 10. The method according to claim 7, wherein the developer is an aqueous solution containing tetramethylammonium hydroxide as a main component. 11. The method of manufacturing a master for a recording medium according to claim 7, wherein the constituent substrate of the master is subjected to pattern etching using the patterned underlayer and the photosensitive material layer as a mask. A method for producing a master for producing a recording medium, comprising: 12. The method according to claim 11, wherein the pattern etching of the constituent substrate of the master is performed by reactive ion etching. 13. The method according to claim 7, wherein the constituent substrate of the master is a transparent substrate.