JPH10235652A - Method of manufacturing master for substrate molding - Google Patents

Abstract

(57) [Problem] To provide a method of manufacturing a substrate forming master capable of forming a substrate having no defect on a signal recording surface. SOLUTION: In a method of manufacturing a substrate forming master in which a substrate forming film corresponding to the shape of a substrate to be formed is formed on a base material, a film forming step of forming a first film on the base material;
A first polishing step of polishing the surface of the first film, a second film forming step of forming a second film made of the same material as the first film on the polished first film, A film obtained through at least a second polishing step of polishing the surface of the second film is defined as a film for forming a substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a substrate forming master provided in a forming die apparatus for forming a disk-shaped recording medium substrate.

[0002]

2. Description of the Related Art Conventionally, a disk master used as a mold when forming a disk-shaped recording medium substrate made of a plastic material is formed so that one surface thereof corresponds to the shape of the substrate to be formed. For example, when manufacturing a disk substrate constituting an optical disk, a disk substrate made of a plastic material is provided by, for example, being provided in a molding die apparatus, and transferring the uneven pattern or the like to a molten polycarbonate resin or the like. Molding.

In manufacturing the master disc, first, as shown in FIG. 14, one surface 10a of a base material 10 of a parallel flat plate made of an optical glass plate or the like is polished extremely smoothly.

[0005] Next, as shown in FIG. 15, a photoresist is applied on one surface 10 a of the base material 10 polished in the above-described process by a spin coating method or the like, thereby forming a resist layer 11. I do.

Next, as shown in FIG. 16, in the manufacture of an optical disk having a concave / convex pattern formed on the surface, a laser beam is directly applied to the resist layer 11 formed on the one surface 10a of the base material 10 in the above-described process. After exposure, a signal corresponding to the concavo-convex pattern is latent-imaged on the resist layer 11.

Next, as shown in FIG. 17, by developing the resist layer 11 on which the concavo-convex pattern has been latently imaged in the above-described process with a developing solution, a portion not exposed to the laser beam is peeled off. The remaining resist layer 12 corresponding to the information signal and the like is formed. The residual resist layer 12 thus formed has a shape corresponding to the concavo-convex pattern transferred to the plastic material.

Next, as shown in FIG. 18, a conductive film layer 13 made of nickel or the like is formed on the concavo-convex pattern made of the remaining resist layer 12 by an electroless plating method or the like.

Next, as shown in FIG. 19, a metal layer 14 made of nickel or the like is formed on the conductive film layer 13 by electroforming.

Next, as shown in FIG. 20, a portion corresponding to a dotted line in FIG. 20 is removed by grinding from the upper surface of the metal layer 14 formed by the above-described process so that the metal layer 14 has a predetermined thickness. To

Next, as shown in FIG. 21, a stamper portion 15 composed of the conductive film layer 13 and the metal film 14 formed by the above-described steps is peeled off from the base material 10, and the center of the stamper portion 15 is removed. A predetermined shape is formed by punching into a donut shape using a punching shear or the like.

The stamper section 15 manufactured as described above includes
On the other hand, an uneven pattern corresponding to the information signal is formed on the surface 15a. The stamper section 15 is provided in a molding die apparatus when producing a disk substrate, and can transfer an uneven pattern onto a plastic material or the like.

[0012]

Incidentally, the above-mentioned master disk is used not only for manufacturing an optical disk but also for manufacturing a disk substrate of a magnetic recording medium having an uneven pattern formed on one surface. As this magnetic recording medium, there is a magnetic recording medium using a substrate on which servo pits are preformed on the surface. In a magnetic recording medium using this substrate, servo pits can be accurately arranged with respect to a data track as compared with a conventional method of recording a servo signal as a magnetic signal. Therefore, this magnetic recording medium can easily achieve higher data density and higher track pitch as compared with the conventional magnetic recording medium.

As described above, when recording / reproducing is performed on a magnetic recording medium on which information signals have been increased in density, a slider on which a magnetic head is mounted is floated above the magnetic recording medium. Do. The slider must fly over the magnetic recording medium with a very small flying height in order to suppress spacing loss when performing recording and reproduction on the magnetic recording medium. In the currently manufactured magnetic recording medium recording / reproducing apparatus, the smallest flying height is about 50 nm.

Further, as a magnetic recording medium, there is a magnetic recording medium in which a concavo-convex pattern corresponding to an information signal is preformed using a substrate made of a glass material or a plastic material. Further, as a substrate of a magnetic recording medium, there is a substrate for a magnetic recording medium in which servo information is preformed.

As described above, when manufacturing a substrate constituting a magnetic recording medium having an uneven pattern formed on one surface, a problem is how to form the uneven pattern on the signal recording surface of the substrate.

As a method of manufacturing a substrate on which the concavo-convex pattern is formed, a glass plate is heated to a state immediately before melting, and a concavo-convex pattern corresponding to an information signal is formed on a signal recording surface of the glass plate. There is a glass press method in which an uneven pattern formed on one surface of a master disk is transferred by pressing the master disk to form an uneven pattern on a glass plate. As another method of forming a concavo-convex pattern on a substrate, similarly to a conventional optical disc, a disc master on which a concavo-convex pattern corresponding to an information signal is formed is mounted in a molding die apparatus. There is an injection molding method in which a molten synthetic resin material is injected into an apparatus, cooled, and cured to produce a substrate on which a concavo-convex pattern is formed.

However, in the above-described substrate manufacturing method, the master disk is formed using a material which is relatively weak to heat, such as nickel. For this reason, it is difficult to use the master disc to transfer the concavo-convex pattern to a molten glass material or the like when transferring the concavo-convex pattern in the above-described glass press method and injection molding method.

Further, in the master disk manufactured by the conventional manufacturing method, if a concave defect is present on the surface on which the concave / convex pattern is formed, a convex portion is formed on the substrate surface formed by the concave portion. If the height of the protrusion on the substrate surface is larger than the flying height of the slider, the protrusion may come into contact with the magnetic recording medium during recording and reproduction of the magnetic recording medium. The problem is that it is significantly impaired.

The present invention has been proposed in view of the above-described problems, and has as its object to provide a method of manufacturing a substrate forming master capable of forming a substrate having no defect on a signal recording surface. Aim.

[0020]

According to the present invention, there is provided a method of manufacturing a substrate master for forming a substrate, the method comprising: forming a substrate forming film corresponding to the shape of a substrate to be formed on a base material; In a method of manufacturing a molding master, a first material is placed on a base material.
A first film forming step of forming a film of the first film, a first polishing step of polishing the surface of the first film, and a second film made of the same material as the first film on the polished first film. A film obtained by at least a second film forming step to be formed and a second polishing step for polishing at least a surface of the second film is used as the substrate forming film.

In the second film forming step, it is preferable that the thickness of the second film is equal to or larger than the thickness of the polished first film.

In the above-described method of manufacturing a substrate forming master, after the second polishing step, a resist layer having a predetermined pattern is formed, and the substrate forming film is etched using the resist layer as a mask. Is desirable.

The method of manufacturing such a substrate forming master is as follows.
A film-forming step of forming a first film on a base material, a first polishing step of polishing the surface of the first film, and forming a first film on the polished first film from the same material as the first film. A film obtained through at least a second film forming step of forming a second film and a second polishing step of polishing at least the surface of the second film is used as the substrate forming film. Therefore, even if a concave defect is formed in the first film, the concave defect is closed by the second film.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a substrate forming master according to the present invention will be described in detail with reference to the drawings.

In the method of manufacturing a master disk to which the present invention described below is applied, for example, a magnetic disk or the like on which an information signal is recorded / reproduced by forming an uneven pattern on one surface and forming a magnetic layer, for example. A method of manufacturing a master disc for forming the above substrate will be described.

The method of manufacturing a disk master described below includes a base material grinding step of forming a base material into a predetermined shape, a base material polishing step of polishing one surface of the base material, and a step of polishing the polished base material. A first film forming step of forming a first film on one surface, a first polishing step of polishing a surface of the first film,
A second film forming step of forming a second film on the second film, a second polishing step of polishing the second film, and forming a resist layer of forming a resist layer on the second film A first heat treatment step of performing a heat treatment on the resist layer, an exposure step of exposing the heat-treated resist layer to laser light, and a developing step of the laser light-exposed resist layer. A developing step of performing a treatment, a second heat treatment step of performing a heat treatment on the remaining resist layer, an etching step of etching to form a concavo-convex pattern on the signal recording surface, and a removing step of removing the remaining resist layer Consists of

In this method of manufacturing a master disc, first,
In the base material grinding step, as shown in FIG. 1, a material having excellent heat resistance to high temperatures is formed by grinding into a predetermined shape. Here, as a material of the base material 1, a stainless alloy or an ultrafine tungsten alloy can be used.
Further, poreless ultrafine ceramic, single crystal silicon, optical glass, or the like may be used.

In this method of manufacturing a master disc, a material made of a stainless steel alloy is used for a thickness of about 15 m.
Grinding is performed so as to form a plate having an inner diameter of about 12 mm and an outer diameter of about 52 mm. The crystal grain size of the base material 1 is desirably small, and is preferably a sintered material from the viewpoint of mechanical strength.

As the material of the base material 1, a material having extremely high hardness and excellent heat resistance to high temperatures is used. However, the material is not limited to these, and in addition to these conditions of hardness and heat resistance, Ultra-fine particles may be used which are finished to an accuracy such that the roughness of one surface upon completion of the base material polishing step is equivalent to that of ceramics or the like. In addition, such a base material 1
Etching is directly applied to the upper surface to form an uneven pattern,
It can be used as a master disc.

Next, in the base material polishing step, as shown in FIG. 2, one side 1a of the base material 1 formed into a predetermined shape in the base material grinding step is polished. Here, the one surface 1a of the base material 1 is a surface on which a first film and a second film are formed in a later step to form an uneven pattern corresponding to lands and grooves.

In this base material polishing step, a flatness of about 500 nm or less is used by using a polishing machine.
Polishing is performed so that the parallelism is about 1 μm or less.
Here, the flatness represents the flatness of the surface,
The degree of parallelism indicates whether the bottom surface and the surface of the base material 1 are parallel.

Next, in the first film forming step, as shown in FIG. 3, the base material 1 having one surface 1a polished in the base material polishing step is formed on the base material 1 by a vacuum deposition method or a sputtering method. A first film 2 is formed. The first film 2 is made of Ir having high hardness, excellent heat resistance at high temperatures, and good releasability from glass or the like. The material of the first film 2 is not limited to Ir but may be Cr, and may be nickel, a platinum alloy, or diamond. The first film 2 has a thickness of about 2
The thickness is about 4 μm.

At this time, the first film 2 has a concave shape due to a concave shape defect on the base material 1 or a defect of the first film 2 itself.
a may occur. Here, as a cause of the formation of the concave portion 2a in the first film 2, there is dust generated in the thin film forming apparatus when forming the first film 2, or abnormal growth of the film itself. In the portion where the abnormal growth of this film has occurred, the first
The properties of the film 2 differ from those of the other portions, and the mechanical strength and the like against polishing and the like are weakened, and the polishing results in a concave portion 2a. As described above, when a concave-shaped defect on the base material 1 or abnormal growth of the first film 2 itself occurs, there is a portion where the first film 2 is not formed and becomes the concave portion 2a.

Next, in the first polishing step, as shown in FIG. 4, the first film 2 formed on the base material 1 in the first film forming step is polished. Here, the polishing of the first film 2 is performed so that the surface roughness Ra is about 2 to 3 nm.

At this time, if the recess 2a is not formed on the first film 2 in the polished state, the process can proceed to the next step, but the first process is performed on one surface 1a of the base material 1. When there is a concave-shaped defect thicker than the film 2 of the first material, or when there is an impurity such as dust on one surface 1a of the base material 1, the concave 2a is formed in the first film 2 and the second film is formed. Then, the process proceeds to the step of forming No. 3.

Next, in the second film forming step, as shown in FIG. 5, when the concave portion 2a formed on the first film 2 is formed, the second film is formed on the first film 2. Form 3 Thus, by forming the second film 3 on the first film 2, the concave portion 2 a formed in the first film 2 is closed. here,
The second film 3 uses the same material as the first film 2 and is formed to be thicker than the first film 2.

Next, in the second polishing step, as shown in FIG. 6, the second film 3 formed on the first film 2 is polished. Here, the polishing is performed until the upper surface of the first film 2 or the upper surface of the first film 2 slightly reaches the base material 1 side. By performing the polishing in this manner, the second film 3 is removed. Thus, the second film 3
Is removed to form a substrate molding film composed of the first film 2 and the second film 3, and the upper surface is used as the signal recording surface 2b.

As described above, the first film 2 is formed on the base material 1, then the second film 3 is formed, and the second film 3 is polished to form a substrate forming film. To form This substrate molding film is in a state where the concave portion 2 a formed in the first film 2 is closed by the second film 3.

It is desirable that the crystal grains of the first film 2 and the second film 3 formed in the first film forming step and the second film forming step be formed as small as possible. It is desirable that the first film 2 and the second film 3 be made of a material having excellent releasability from a synthetic resin material such as glass.

Next, in a resist layer forming step, as shown in FIG. 7, a photoresist is applied to a thickness of about 0.43 nm by spin coating to form a resist layer 4 on the substrate forming film. .

Next, in the first heat treatment step, as shown in FIG.
By performing a heat treatment for about a minute, the resist layer 4 is hardened.

Next, in the exposure step, as shown in FIG.
The resist layer 4 hardened in the above-described process is exposed to a pattern based on a recording signal using, for example, a laser light exposure device or the like. By exposing the resist layer 4 to the laser beam, a latent image corresponding to the recording signal is formed on the resist layer 4.

Next, in the developing step, as shown in FIG. 10, the resist layer 4 is immersed in the developing solution for a predetermined time according to the material of the resist layer 4 and the material of the developing solution. here,
The resist layer 4 is immersed in a developer for about 90 seconds, for example. As described above, by immersing the resist layer 4 in the developing solution, the portion of the resist layer 4 that has been exposed to the laser light in the exposure step is peeled off, and only the portion that has been exposed to the laser light is used as the remaining resist layer 4a. It is formed on a film for molding.

Next, in the second heat treatment step, as shown in FIG. 11, the remaining resist layer 4a formed in the concavo-convex pattern in the above-mentioned step is subjected to heat treatment at a temperature of about 120 ° C. for about 60 minutes. By baking.

Next, in the etching step, as shown in FIG. 12, etching is performed on the signal recording surface 2b of the substrate forming film to form an uneven pattern. Here, in this etching step, a portion exposed from between the remaining resist layers 4a is etched by a dry etching method, an electron beam ion etching method, or the like. As described above, by performing the etching, an uneven pattern corresponding to the information signal is formed on the substrate forming film. In the method of manufacturing a master disc to which the present invention is applied, etching is performed to a depth of about 0.2 μm from the upper surface of the substrate forming film. As described above, by etching the signal recording surface 2b of the substrate molding film,
The lands corresponding to the recording signals are formed so as to be concave portions, and the grooves are formed so as to be convex portions.

In the above-described method of manufacturing a master disc, a dry etching method or an electron beam ion etching method is used as a means for forming a concavo-convex pattern on a substrate forming film. However, the present invention is not limited to this. Various etching methods such as a method can also be applied.

Next, in the stripping step, as shown in FIG. 13, the remaining resist layer 4 remaining on the substrate forming film is stripped and removed using a stripping material such as acetone.

The disc master manufactured in this manner has a first film-forming step of forming a first film 2 on a base material 1 and a first film-forming step.
A first polishing step of polishing the film 2, a second film forming step of forming the second film 3 on the first film,
And a second polishing step of polishing the film 3 of the first layer.
Even if the concave portion 2 a is formed in the film 2, the concave portion 2 a can be closed by the second film 3. Therefore, according to this method of manufacturing a master disk, it is possible to manufacture a master disk having no concave defects on the signal recording surface 2b of the film for forming a substrate. Therefore, according to this disk master, even when a signal is transferred to a glass material, a synthetic resin material, or the like in accordance with the concavo-convex pattern formed on the signal recording surface 2b of the substrate molding film, the convex projections are formed. No disk substrate can be molded.

The master disk manufactured as described above uses a material having very high hardness and excellent heat resistance at high temperatures as the material of the base material 1, the first film 2, and the second film 3. Therefore, it has a property that it can sufficiently withstand a glass pressing step of transferring a concave and convex pattern by pressing against a glass material immediately before melting. Further, this disk master is provided, for example, in a molding die apparatus, and can also be applied as a die for producing a disk substrate by transferring an uneven pattern to a molten synthetic resin.

Here, a master disk manufactured by a conventional manufacturing method is usually made of Ni or the like and has a thickness of about 0.3 mm to 0.5 mm. In such a disc master, since the length in the thickness direction is much thinner than the length in the radial direction, the flatness of the surface on which the concavo-convex pattern is formed deteriorates. On the other hand, in the master disc manufactured by the manufacturing method to which the present invention is applied,
A material whose hardness is much higher than that of Ni can be formed as the base material 1 and the thickness of the base material 1 can be adjusted on the order of millimeters. Therefore, in the disk master manufactured by the manufacturing method to which the present invention is applied,
The flatness of the surface on which the concavo-convex pattern is formed can be reduced to 1 μm or less without the flatness being deteriorated unlike the disk master by the conventional manufacturing method. Therefore, according to this disk master, a disk substrate having excellent flatness of the signal recording surface can be manufactured.

In the above-described method of manufacturing a master disc, the first film 2 is formed on the base material 1, the second film 3 is formed on the first film 2, and the concave portions 2a are formed. Although a film having no layer is formed, a film to be laminated on the first film 2 may be formed two or more times. That is, in the above-described method for manufacturing a master disk, after the second film forming step for forming the second film 3 and the second polishing step, whether or not the concave portion 2a is formed on the first film 2 It is checked that if the concave portion 2a is formed, a second film forming step may be performed again, and a second polishing step may be performed on the second film 3. is there. As described above, by performing the second film forming step two or more times, it is possible to form a substrate forming film on the base material 1 without the concave portion 2a on the surface of the substrate forming film.

In the above description, the method of manufacturing a disk master having an uneven pattern formed on one surface has been described. However, the present invention is not limited to this, and the method of manufacturing a disk master according to the present invention uses a smooth disk substrate. The present invention can also be applied as a method of manufacturing a disk master to be manufactured. Since such a disk master does not have any irregularities or the like on one surface, it is possible to manufacture a disk substrate having a smooth surface.

[0053]

As described above in detail, the method of manufacturing a master for forming a substrate according to the present invention comprises a film forming step of forming a first film on a base material, and polishing the surface of the first film. A first polishing step, a second film forming step of forming a second film made of the same material as the first film on the polished first film, and at least a surface of the second film. A second polishing step of polishing,
The film obtained by at least passing through is used as a substrate molding film. Therefore, even if a concave defect or the like occurs in the first film, the film is formed in the first film by forming the second film. It is possible to close the recessed defect. Therefore, according to the method of manufacturing a substrate forming master, it is possible to manufacture a substrate forming master having no concave-shaped defect on the surface on which the uneven pattern to be transferred to the substrate is formed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a base material.

FIG. 2 is a cross-sectional view showing an example of a state in which one surface of a base material has been polished.

FIG. 3 is a cross-sectional view illustrating an example of a state in which a first film is formed on one surface of a base material.

FIG. 4 is a cross-sectional view showing an example of a state where the first film is polished.

FIG. 5 is a cross-sectional view showing an example of a state where a second film is formed on the first film.

FIG. 6 is a cross-sectional view showing an example of a state where the second film is polished.

FIG. 7 is a cross-sectional view illustrating an example of a state where a resist layer is formed on a first film.

FIG. 8 is a cross-sectional view showing an example of a state in which a heat treatment has been performed on the resist layer.

FIG. 9 is a cross-sectional view showing an example of a state in which a laser beam is exposed to a resist layer to form a latent image of an uneven pattern.

FIG. 10 is a cross-sectional view showing an example of a state in which a developing process has been performed on the resist layer.

FIG. 11 is a cross-sectional view showing an example of a state in which a heat treatment has been performed on the remaining resist layer.

FIG. 12 is a cross-sectional view illustrating an example of a state where the first film is etched.

FIG. 13 is a cross-sectional view showing an example of a state in which a residual resist layer has been removed.

FIG. 14 is a cross-sectional view showing an example of a base material in a conventional method of manufacturing a master disk.

FIG. 15 is a cross-sectional view showing a state in which a resist layer is applied on a base material in a conventional method for manufacturing a master disk.

FIG. 16 is a cross-sectional view showing a state in which a resist pattern is exposed to laser light to form a latent image of a concavo-convex pattern in a conventional method for manufacturing a master disk.

FIG. 17 is a cross-sectional view showing a state where a resist layer has been subjected to a development process in a conventional method of manufacturing a master disk.

FIG. 18 is a cross-sectional view showing a state in which a conductive film layer is formed on a residual resist layer in a conventional method for manufacturing a master disk.

FIG. 19 is a view showing a state in which a metal film is formed on a conductive film layer in a conventional method of manufacturing a master disk.

FIG. 20 is a cross-sectional view showing a state where a part of the metal film is removed.

FIG. 21 is a cross-sectional view showing a state where a stamper portion is peeled off from a base material.

[Explanation of symbols]

 Reference Signs List 1 base material, 2 first film, 2a recess, 3 second film

Claims (4)

[Claims] 1. A method for manufacturing a substrate forming master in which a substrate forming film corresponding to the shape of a substrate to be formed is formed on a base material, a film forming step of forming a first film on the base material. A first polishing step of polishing a surface of the first film; and a second polishing step of forming a second film made of the same material as the first film on the polished first film. A film forming step, and a second polishing step of polishing at least a surface of the second film, wherein a film obtained by passing at least a film is used as the film for forming a substrate. Method. 2. The production of a substrate forming master according to claim 1, wherein in the second film forming step, the thickness of the second film is equal to or greater than the thickness of the polished first film. Method. 3. The substrate forming method according to claim 1, wherein after the second polishing step, a resist layer having a predetermined pattern is formed, and the substrate forming film is etched using the resist layer as a mask. Production method for master disks. 4. The method according to claim 1, wherein the first film and the second film are made of Ir or Cr.
The method for producing a substrate forming master according to claim 1, wherein the substrate is formed by: