JPH11291256A - Molding die, manufacture of molding die, recording medium and manufacture of recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control generation of undulations and projections as much as possible and form a base of good surface properties by making a metal film adhere on a recessed section formed on the surface being in contact with a molded product and embedding the same thereon. SOLUTION: A photoresist film so patterned as to expose a recessed section 3c is used as a mask, and a recessed section 2a is coated with a metal film 6 by spattering. Then the photoresist film is melted and released to manufacture a molding die 1 in the state that only an exposed section as the recessed section 3c is made to adhere on the metal film 6 and embedded thereon is manufactured. In the case, for instance, the thickness of the metal film 6 is thickener than the depth of the recessed section 3c, a protruded section 6a on the molding die 1 is formed by a peripheral edge of the metal film 6 embedding the recessed section 3c. As a result, a recessed section 20a is formed to a certain extent on a disk base 20 molded by using the mold die 1, while a protrusion generating the cause of the contact with a head is not formed thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die, a method of manufacturing the molding die, a recording medium having a substrate formed by the molding die, a method of manufacturing the recording medium, and About. More specifically, it relates to improvement of the surface shape of a molding die.

[0002]

2. Description of the Related Art As a recording medium, for example, a magnetic disk on which an information signal is written magnetically, an optical disk on which an information signal is written in advance by emboss pits, and an information signal are written using a phase change of a recording film. There are a phase change type optical disk and a magneto-optical disk on which an information signal is written using a magneto-optical effect of a recording film. These recording media are formed by forming a functional film such as a recording film on a disk-shaped substrate.

In particular, the substrate in such a recording medium is, for example, a substrate used for a magnetic disk,
In the case of a substrate that is manufactured by polishing the surface of a substrate made of glass or aluminum or is used for an optical disk, the molten resin is injected into a mold having a thin plate-shaped stamper made of nickel with a thickness of about 300 μm, and then cooled. It is manufactured by an injection molding method.

[0004] Above all, a resin substrate produced by the injection molding method is advantageous in terms of production cost because it is produced without using a polishing step like the above-mentioned substrate made of glass, aluminum or the like. In view of the manufacturing cost, not only the optical disk and the magneto-optical disk, but also a magnetic disk using a resin substrate molded by an injection molding method has been proposed.

[0005]

However, a resin substrate formed by using a metal mold having a thin plate-shaped stamper may have undulations and projections. here,
The undulation of the resin substrate is caused by deformation of the thin stamper due to heat and pressure during injection molding. Further, the reason why the protrusions are formed on the resin substrate is that minute holes are present on the surface of the thin stamper.

As a result, a recording medium using a substrate having such undulations and projections has poor surface properties with projections and undulations on the surface, which hinders an improvement in recording density. There is.

More specifically, in the case of a magnetic disk, if there are projections on the disk surface, the projections will collide with the magnetic head, causing damage to the magnetic disk or the head, or a reproduction signal when reproducing an information signal. However, there is a problem that disturbance occurs. For this reason, it is desirable that a substrate having a height of several tens of nm or more does not exist on a substrate used for a magnetic disk.

In recent years, similarly to the magnetic disk, an attempt has been made to use a floating type head for an optical disk. In order to achieve higher density recording, the distance between the optical head and the disk surface has to be increased. Needs to be reduced. Therefore, it is desirable that the substrate used for the optical disc also has no protrusion or undulation on the surface.

Accordingly, the present invention has been proposed in view of such circumstances, and a molding die capable of molding a substrate having excellent surface properties by suppressing generation of undulations and projections as much as possible. An object of the present invention is to provide a method of manufacturing a molding die, a recording medium having a good surface property using a substrate in which generation of undulations and projections is minimized, and a method of manufacturing the recording medium.

[0010]

According to the present invention, the above object has been attained by providing a molding die in which a depression existing on a surface in contact with a molded product is filled with a metal film. It is a feature.

As described above, the molding die according to the present invention comprises:
Since the depression existing on the surface in contact with the molded product is filled, the surface in contact with the molded product is smoothed as much as possible, and the surface properties are improved. As a result, according to the molding die according to the present invention, a substrate having good surface properties with minimal generation of protrusions is molded.

Further, in the method of manufacturing a molding die according to the present invention, when manufacturing the molding die, the recess existing on the surface in contact with the molded product is filled by applying a metal film. It is characterized by the following.

As described above, in the method for manufacturing a molding die according to the present invention, since the depressions existing on the surface in contact with the molded product are filled with the metal film, the surface is smoothed as much as possible and the surface property is excellent. A molding die is obtained.

Further, the recording medium according to the present invention has at least a recording film on a substrate, and the substrate is filled with a metal film to cover a dent present on a surface in contact with a molded product. It is characterized by being molded using a molding die made of:

As described above, in the recording medium according to the present invention, the substrate is formed by using a molding die whose surface is made as smooth as possible by filling the depressions present on the surface in contact with the molded product with the metal film. Since the substrate is molded, the substrate has good surface properties with the projections suppressed as much as possible, and as a result, a recording medium having good surface properties is obtained.

Further, according to the method of manufacturing a recording medium of the present invention, a substrate is formed by using a molding die that is filled with a metal film to cover a depression existing on a surface in contact with a molded product. And at least a recording film is formed on the substrate.

As described above, the method for manufacturing a recording medium according to the present invention uses a molding die whose surface is made as smooth as possible by filling the pits existing on the surface in contact with the molded product with the metal film. Since the substrate is formed by molding, the substrate has good surface properties with the projections suppressed as much as possible, and as a result, a recording medium having good surface properties can be obtained.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

In the present invention, as a method of molding a substrate, a resin is directly molded using a molding die to which the present invention is applied without using a thin plate-shaped stamper that causes large undulation of the substrate. The method used is used. Hereinafter, a molding die used for injection molding will be described as a molding die to which the present invention is applied, but the molding die to which the present invention is applied is not limited to injection molding. FIG. 1 is a perspective view showing an example of a molding die to which the present invention is applied.

A molding die 1 is provided on a disk-shaped mold substrate 2 attached to an injection molding apparatus, in a disk-shaped mold having an outer diameter slightly larger than the outer diameter of a disk substrate to be molded. The mold base material 3 is provided. The molding die 1 is made of, for example, a stainless metal. The surface 3a of the disk-shaped mold base material 3 is a molding surface that forms the disk substrate surface. The surface 3a of the mold base material 3 is mirror-polished, and a center hole 3b is provided at the center. Specifically, the mold base material 3 has a diameter of about 10 cm and a thickness of about 2 cm. In addition, as the molding die 1, the entire surface 3a of the mirror-polished die base material 3
After the metal film is deposited by sputtering, the metal film may be polished again.

By the way, as described above, a conventional molding die is one obtained by mirror-polishing the surface of a die base material, or a metal film is deposited on the entire surface of the die base material by sputtering. Those polished later are used. Such conventional molding dies cause protrusions on the molded substrate as confirmed from the results of precise inspection of the molding dies and surface analysis of the molded disk substrate. The depression was present on the molding surface. Therefore, a substrate molded using a conventional molding die having a depression on such a molding surface has an undesirable surface property with projections formed on the surface.

Therefore, in particular, the molding die 1 to which the present invention is applied has a concave portion existing on the surface 3 a of the die base material 3.
The hole is filled by applying a metal film. In addition, the material of the metal film that fills the dents existing on the surface 3a of the mold base material 3 is not particularly limited,
Ti is suitable because of its low stress. Also, in FIG.
The metal film is omitted and not shown.

As described above, in the molding die 1 to which the present invention is applied, since the recess existing in the surface 3a of the molding base material 3 serving as the molding surface is filled, the surface 3a of the molding base material 3 is filled. Is smoothed as much as possible to improve the surface properties. As a result, according to the molding die 1 to which the present invention is applied, the occurrence of projections is suppressed as much as possible, and a disk substrate having excellent surface properties is molded.

The projections described here are defined as follows. On a normal smooth surface, the maximum height Rmax is about 10 times the center line average roughness Ra. Therefore, a convex portion having about 20 times the center line average roughness Ra can be clearly judged as a protrusion. Therefore, a protrusion that is about 20 times the center line average roughness Ra is defined as a protrusion.

A method of manufacturing the molding die 1 to which the present invention having the above structure is applied will be described below. More specifically, referring to FIGS. 2 to 7, a method of filling a hollow portion present on the molding surface of molding die 1 with a metal film when producing molding die 1 to which the present invention is applied. Will be described in detail.

First, the mold base material 3 whose surface 3a is mirror-polished
Is prepared on the mold substrate 2. Then, with respect to the mold base material 3, all of the depressions 3 c as shown in FIG. 2 existing on the surface 3 a of the mold base material 3 are replaced with, for example, an optical microscope or an atomic force microscope (Atomic Force Microscope).
And record the position and depth.

Next, for example, the mold base material 3 is washed with a neutral detergent and pure water, and thereafter, as shown in FIG. 3, a positive photoresist is applied on the surface 3a of the mold base material 3. Then, a photoresist film 4 having the same thickness as the maximum depth is formed among the above-listed depressions.

Next, the concave portion 3c in which the position and the depth are recorded in advance is searched from the photoresist film 4 by an optical microscope. At this time, a filter that cuts short-wavelength light that is exposed to the resist by the light source of the optical microscope is provided so that the photoresist film 4 applied on the surface 3a of the mold base material 3 is not exposed to the illumination light of the optical microscope. Mount and use only light that has passed through this filter.

Here, the molding die is positioned with respect to the optical microscope so that one of the depressions 3c to be filled with a metal film to fill the hole is located at the center of the visual field, and the magnification of the objective lens is increased. The maximum magnification is set within a range in which the entire recess 3c can be seen.

Then, stop down the field stop of the optical microscope,
The field of view of the optical microscope and the size of one dent 3c are adjusted to be the same.

Next, the visual field of the optical microscope is changed to one of the concave portions 3c.
In this state, the filter attached to the light source of the optical microscope is removed, and as shown in FIG. 4, the photoresist film 4 on the depression 3c is irradiated with white light 5 for exposure. By this operation, it is possible to expose only the portion that was visible through the eyepiece of the optical microscope.

Then, the exposure operation of the photoresist film 4 formed on the recess 3c is performed on each recess existing on the surface 3a of the mold base material 3.

Next, the photoresist film 4 thus exposed is developed with a developing solution. Then, the exposed portion of the photoresist film 4 is dissolved, and as shown in FIG.
The depression 3c, which was a defect of the molding die 1, is exposed. After that, if necessary, the temperature of the patterned photoresist film 4 is increased to promote the polymerization reaction, thereby increasing the strength.

Next, as shown in FIG. 6, using the photoresist film 4 patterned so that the recess 3c is exposed as a mask, a metal film 6 is deposited on the recess 3c by sputtering. At this time, the metal film 6 is applied to a thickness equal to or slightly larger than the depth of the recess 3c measured in advance. As a method for forming the metal film 6, a conventionally known thin film forming method such as a vapor deposition method can be used in addition to sputtering.

Finally, as shown in FIG. 7, the present invention is applied in a state in which the metal film 6 is applied only to the exposed portion which is the concave portion 3c by filling and filling the photoresist by dissolving and peeling the photoresist. A molding die 1 is obtained.

Here, for example, when the thickness of the metal film 6 is slightly larger than the depth of the recess 3c, the molding die 1
As shown in FIG. 5, the peripheral portion of the metal film 6 that fills the recess 3c forms a convex portion 6a. As a result, the disk substrate 20 molded using the molding die 1 has a slight recess 20a as shown in FIG. 8, but no projection which has conventionally caused contact with the head is not formed.

As described above, according to the method of manufacturing a molding die to which the present invention is applied, when the molding die 1 is manufactured, the molding surface is formed on the surface 3a of the mold base material 3 which is the molding surface. Since the existing depression 3c is filled with the metal film 6, the molding die 1 having a smooth surface as much as possible and having good surface properties can be obtained.

Next, a method of manufacturing a disk substrate using the molding die 1 thus manufactured will be described in detail below. FIG. 9 is a sectional view showing a main part of an injection molding apparatus 10 provided with a molding die 1 to which the present invention is applied.

First, the injection molding apparatus 10 comprises: a fixed mold 7 for forming one main surface of a disk substrate;
And a peripheral mold 12 that forms the other main surface of the disk substrate and forms an outer peripheral side surface of the disk substrate. Here, the fixed mold 7 and the movable mold 8 are the molding dies 1 to which the present invention shown in FIGS. 1 and 7 is applied.

The movable mold 8 moves toward and away from the fixed mold 7 by a drive mechanism (not shown). The outer peripheral mold 12 is
The injection molding apparatus 10 includes a fixed outer mold 12a and a movable outer mold 12b that fix the fixed mold 7 and the movable mold 8 in the injection molding apparatus 10, respectively. The outer peripheral mold 12 forms the outer peripheral side surface of the molded product. The fixed mold 7 and the movable mold 8
The outer mold 12 forms a cavity 11 that cooperates with the mold in a clamped state to form a disk substrate.

In particular, the fixed mold 7 and the movable mold 8 are shown in FIG.
And a molding die to which the present invention shown in FIG. 7 is applied. That is, the fixed mold 7 and the movable mold 8 are filled with the metal film 6 to cover the dents 3c which are defects existing on the surfaces 7a and 8a of the mold base material as the respective molding surfaces. It is made.

As described above, in the fixed mold 7 and the movable mold 8 using the molding die 1 to which the present invention is applied, since the recess 3c existing in the molding surface is filled with the metal film 6, The surface is smoothed as much as possible, and the surface properties are improved.

On the side of the fixed mold 1a, a molten synthetic resin material
1 is provided with a sprue bush 15 having a nozzle 14 for injection filling. On the movable mold 1b side, a first cylindrical shape having an outer diameter corresponding to a region where an information signal is not recorded on the inner peripheral side of the disk substrate to be molded is provided at a position corresponding to the center of the cavity 11. Eject member 1
6 is provided movably in the axial direction. The first ejecting member 16 releases the molded disk substrate from the movable mold 1b by projecting into the cavity 11 by a driving means (not shown) during the releasing operation of the disk substrate.

The first eject member 16 is provided with a punch 17 for forming a center hole of a disk substrate formed on the inner peripheral side thereof. A second ejection member 18 is attached to the inner peripheral side of the punch 17 so as to be able to advance and retreat in the axial direction. The second eject member 18 releases the synthetic resin material of the cut portion from the movable mold 12b after the center hole of the disk substrate is formed by the punch 17.

The injection molding apparatus 10 configured as described above
First, by operating a drive mechanism (not shown), the movable mold 8 is moved closer to the fixed mold 7 to be in a mold-clamped state, thereby forming a cavity 11 whose periphery is closed.

Next, the synthetic resin material melted from the nozzle 14 of the sprue bush 15 is injected and filled into the cavity 11 in a mold clamping state. Then, the synthetic resin material is cooled to a semi-molten state by a temperature control mechanism (not shown) provided in the injection molding apparatus 10, and the punch 17 is moved from the center hole of the first eject member 16 toward the fixed mold 7. A center hole of the disk substrate to be formed by the protruding operation is formed, and this cut portion is connected to the second ejection member 18.
Release from the movable mold 8.

Thereafter, in the injection molding apparatus 10, the injection-filled synthetic resin material is cooled and hardened by a temperature control mechanism (not shown).

In the injection molding apparatus 10, a driving mechanism (not shown) operates to separate the movable mold 8 from the fixed mold 7, thereby performing a mold opening operation. Finally, the disk substrate molded in the cavity 11 is protruded from the movable mold 8 side by the first ejecting member 16 and is removed by a disk substrate removal mechanism (not shown).

In the injection molding apparatus 10, the molding die 1 to which the present invention is applied may be used for either the fixed die 7 or the movable die 8.

As described above, the disk substrate formed by using the molding die 1 to which the present invention is applied is formed by depositing the concave portion on the molding surface of the molding die 1 with a metal film. As a result, the molding surface of the molding die 1 is smoothed as much as possible. As a result, a disk substrate having a good surface property is obtained, in which the occurrence of projections is minimized and the surface is smoothed.

Next, the configuration of a recording medium to which the present invention is applied using the disk substrate formed as described above will be described below. FIG. 10 is a sectional view showing a main part of a magnetic disk to which the present invention is applied. FIG. 11 is a sectional view showing a main part of another magnetic disk to which the present invention is applied. FIG. 12 is a perspective view showing a main part of another magnetic disk to which the present invention shown in FIG. 11 is applied.

In the following, a magnetic disk and a magneto-optical disk will be described as recording media to which the present invention is applied, but the recording medium to which the present invention is applied is formed on a substrate formed by using a molding die 1. The recording medium is not limited to these as long as it has a recording film.

The recording medium to which the present invention is applied records on a disk-shaped substrate (hereinafter, referred to as a disk substrate) formed by using the molding die 1 to which the present invention is applied as described above. A functional film such as a film is formed. That is, the recording medium according to the present invention includes at least a recording film on a resin disk substrate, and the disk substrate fills in the depressions 3c present on the surface in contact with the molded product by applying the metal film 6. It is formed by using the formed molding die 1.

More specifically, the magnetic disk 40
As shown in (1), a magnetic film 42 is formed on a disk substrate 41 formed by using a molding die 1 to which the present invention is applied.

As described above, in the magnetic disk 40 to which the present invention is applied, the disk substrate 41 is molded by the molding die 1 whose surface is made as smooth as possible and has good surface properties. Is as good as possible, with the surface properties suppressed as much as possible.
Since the recording / reproducing characteristics are excellent and the flying height of the flying head can be reduced as much as possible, the magnetic disk 40 with high reliability that can sufficiently cope with higher density recording can be obtained.

As shown in FIG. 11, a magnetic disk 50 is formed on a disk substrate 51 on which a concave portion 50a and a convex portion 50b of a predetermined pattern are formed.
2 are formed. In the magnetic disk 50, as shown in FIG. 11, the concave portions 50a and the convex portions 50b between the concave portions 50a are magnetized to have opposite polarities.

More specifically, the concave portion 50a having the predetermined pattern
The projection 50b is a concavo-convex pattern corresponding to a guard band, a servo signal, or a read-only signal. For example, as shown in FIG. 12, a magnetic disk 50 has an information recording area 55 in which a concave portion 53 along a recording track is formed as a guard band and an information signal is recorded, and a concave portion corresponding to at least a control signal including a servo signal. A control signal recording area 56 in which the control signal is recorded by forming the protrusions between the recesses 54 and magnetizing the recesses 54 with the polarities opposite to each other is provided in the disk surface. Although not shown, the magnetic disk 50 shown in FIG. 12 may have an uneven pattern corresponding to the read-only signal formed in the information recording area 55. In FIG. 12, the track pitch is indicated by Tp, and the radial direction is indicated by R.

As described above, in the magnetic disk 50 to which the present invention is applied, the surface of the molding die 1 to which the present invention is applied is smoothened as much as possible. An uneven pattern is formed, and a predetermined pattern of unevenness is formed on the disk substrate 51 using the molding die. Thereby, the disk substrate 51 has a good surface property in which the projections and depressions of the predetermined pattern are formed with high precision and the projections are suppressed as much as possible. As a result, this disk substrate 5
The magnetic disk 50 using No. 1 has good surface properties, excellent recording / reproducing characteristics, and the flying height of the flying head can be reduced as much as possible. The magnetic disk 50 is obtained.

The magnetic disk 40 to which the present invention having the above structure is applied is manufactured as described below.

First, the disk substrate 41 is connected to the above-described FIG.
It is molded by an injection molding method by an injection molding apparatus 10 provided with a molding die 1 to which the present invention is applied, which is manufactured as shown in FIG.

In other words, in manufacturing the disk substrate 41 of the magnetic disk 40, the metal mold 6 is used to cover the depression 3c existing on the surface in contact with the molded product with the metal mold 6 and to fill the hole. Then, the disk substrate 41 is formed by injection molding. In addition, as a molding method of the disk substrate, injection molding is preferable.

As described above, according to the method of manufacturing the magnetic disk 40 to which the present invention is applied, the concave portion 3 c existing on the surface in contact with the molded product is filled with the metal film 6 so that the surface is made as smooth as possible. Since the disk substrate 41 is formed using the mold 1, the disk substrate 41 having excellent surface properties with the projections suppressed as much as possible can be obtained.

Next, the disk substrate 4 thus obtained is
For example, as shown in FIG. 10, a magnetic film 42 made of a CoCrTa alloy is formed on the substrate 1 by sputtering, and finally a magnetic disk 40 is obtained.

On the other hand, the magnetic disk 50 to which the present invention is applied
Is manufactured as described below.

First, the disk substrate 51 is formed as shown in FIG.
16 through a process as shown in FIG. 16 by a photolithography technique.

First, in order to manufacture a disk substrate 51 on which a concavo-convex pattern corresponding to a signal is formed, a photolithography technique is used to mount a disk on a molding surface of a molding die 1 to which the present invention is applied. A concavo-convex pattern that is opposite to the concavo-convex pattern to be formed is formed.

That is, first, using the molding die 1 to which the present invention is applied, in which the recess 3c existing on the molding surface is filled with the metal film 6 as shown in FIGS. Surface 3a of mold base material 3, which is the molding surface of molding die 1.
As shown in FIG. 13, a positive photoresist is uniformly applied thereon to form a photoresist film 20.

Then, as shown in FIG. 14, a concave / convex pattern opposite to the pattern corresponding to the servo signal or the read-only signal is exposed on the photoresist film 20 using the master exposure apparatus. At this time, the unexposed portion becomes a concave portion on the formed disk substrate as a result.

Next, as shown in FIG. 15, by developing the photoresist film 20, the exposed portion of the photoresist is dissolved, and the concave portion 21 having a predetermined pattern on the molding die 1 is exposed.

Next, as shown in FIG. 16, the exposed concave portion 21 of the predetermined pattern on the molding die 1 is etched by an etching method such as ion milling. A concave portion 22 having a depth of about 100 nm is formed on the surface 3a of the material 3.

Then, by peeling and washing the photoresist film 20, a molding die as shown in FIG. 17 in which a predetermined concavo-convex pattern corresponding to a signal is formed can be produced.

Finally, a molten resin is filled in an injection molding apparatus provided with the molding die, and a disk substrate 51 having a predetermined uneven pattern as shown in FIG. 11 is formed by the injection molding method. Molded.

As described above, in the method of manufacturing the magnetic disk 50 to which the present invention is applied, when the disk substrate 51 is manufactured, the surface of the molding die 1 to which the present invention is applied is smoothened as much as possible. Then, a concavo-convex pattern opposite to the concavo-convex pattern corresponding to various signals is formed, and a predetermined pattern of concavities and convexities is formed on the disk substrate 51 using the molding die. As a result, according to the method of manufacturing the magnetic disk 50 to which the present invention is applied, the disk substrate 51 having a good surface property in which projections and depressions of a predetermined pattern are formed with high precision while suppressing projections as much as possible.

As described above, the magnetic film 52 is formed on the disk substrate 51 on which the predetermined concavo-convex pattern corresponding to the signal is formed, thereby forming the concavo-convex pattern corresponding to the information signal, the servo signal, and the like. The magnetic disk 50 shown in FIGS. 11 and 12 can be obtained.
The magnetic disk 50 has, as shown in FIG.
By magnetizing Ob and the concave portion 50a with opposite polarities, a reproduced signal can be obtained in the concave portion 50a.

Here, in order to magnetize the convex portion 50b and the concave portion 50a of the magnetic disk 50 with respective opposite polarities, the magnetic disk 50 is set in a magnetizing device (not shown).
As shown by an arrow a in FIG. 18, the magnetic disk 50 is rotated. Then, as shown in FIG. 18, while supplying the first DC current to the magnetizing magnetic head 48 provided in the magnetizing device, the magnetizing magnetic head 48 is moved to the magnetic disk 50.
The magnetic disk 52 is moved at a predetermined track pitch in the radial direction, and the entire surface of the magnetic film 52 of the convex portion 50b and the concave portion 50a of the magnetic disk 50 is magnetized in the same direction.

Thereafter, as shown in FIG. 19, a second DC current having a polarity opposite to that of the first DC current and having a smaller current value than the first DC current is supplied to the magnetizing magnetic head 48. While moving the magnetizing magnetic head 48 at a predetermined track pitch in the radial direction of the magnetic disk 50, only the magnetic film 42 of the convex portion 50a of the magnetic disk 50 is magnetized in the opposite direction, so that the servo signal and the like are generated. Write.

On the other hand, the magneto-optical disk 6 to which the present invention is applied
Reference numeral 0 denotes a first dielectric film 62, a recording film 63, and a second dielectric film 62 on a disk substrate 61 formed by using a molding die 1 to which the present invention is applied, as shown in FIG. Membrane 64,
The light reflection film 65 and the protection film 66 are sequentially laminated.
The disk substrate 61 of the magneto-optical disk 60 has a predetermined pattern of irregularities. The unevenness of the predetermined pattern is an unevenness pattern corresponding to a guard band, a servo signal, or a read-only signal. In FIG. 20, the concavo-convex pattern formed on the disk substrate 61 is omitted.

As described above, in the magneto-optical disk 60 to which the present invention is applied, the molding surface of the molding die 1 to which the present invention is applied, whose surface is as smooth as possible, is opposite to the concavo-convex pattern corresponding to various signals. Is formed, and a predetermined pattern of concavities and convexities is formed on the disk substrate 61 using the molding die. Accordingly, the disk substrate 61 has a good surface property in which projections and depressions of a predetermined pattern are formed with high precision by minimizing protrusions. As a result, the magneto-optical disk 60 using the disk substrate 61 has good surface properties,
Since the recording / reproducing characteristics are excellent and the flying height of the flying head can be reduced as much as possible, the magneto-optical disk 60 with high reliability that can sufficiently cope with higher density recording can be obtained.

The magneto-optical disk 60 configured as described above is manufactured as follows using the disk substrate 61 manufactured by the molding die 1 to which the present invention is applied.

First, in the disk substrate 61, using the molding die 1 to which the present invention is applied, a concave portion along the recording track is formed by the same photolithography technique as in the process shown in FIGS. Disk substrate 61 formed
Is injection molded.

As described above, according to the method of manufacturing the magneto-optical disk 60 to which the present invention is applied, the surface of the molding die 1 to which the present invention is applied is smoothened as much as possible, and the uneven pattern corresponding to various signals is formed on the molding surface. A concavo-convex pattern reverse to that described above is formed, and a predetermined pattern of concavities and convexities is formed on the disk substrate 61 using the molding die. As a result, according to the method of manufacturing the magneto-optical disk 60 to which the present invention is applied, the disk substrate 61 having a good surface property on which the protrusions and depressions of the predetermined pattern are formed with high accuracy and the projections are suppressed as much as possible.

Then, the first dielectric film 6 made of, for example, SiN is formed on the disk substrate 61 thus manufactured.
2. A recording film 63 made of a TbFeCo alloy, a second dielectric film 64 made of SiN, and a light reflection film 65 made of Al are sequentially formed by sputtering, and an ultraviolet curing resin is spin-coated on the light reflection film 65. A protective film 66 is formed by coating by a method, and finally a magneto-optical disk 60 as shown in FIG. 20 is obtained. In FIG. 20, a predetermined concavo-convex pattern formed on the disk substrate 61 is not shown. In such a magneto-optical disk 60, the amount of reflected light is reduced at the concave portion. Therefore, by forming the concave and convex shape, a servo signal and a read-only signal can be written in advance.

As described above, according to the method of manufacturing a recording medium to which the present invention is applied, the concave portion 3c existing on the surface in contact with the molded product is filled with the metal film 6 so that the surface is made as smooth as possible. In order to form the disk substrates 41, 51, 61 using the mold 1, the disk substrate 41,
As a result, the surface properties of the projections 51 and 61 were suppressed as much as possible, and as a result, the surface properties were good, the recording / reproducing characteristics were excellent, and the high reliability that could sufficiently cope with further high-density recording was obtained. The recording media 40, 50, and 60 can be obtained.

[0084]

As described above in detail, in the molding die according to the present invention, since the dents existing on the surface in contact with the molded product are filled, the surface in contact with the molded product is smoothed as much as possible. The surface properties are improved. As a result, according to the molding die according to the present invention, it is possible to mold a substrate having excellent surface properties, in which the generation of projections is suppressed as much as possible.

Further, in the method of manufacturing a molding die according to the present invention, since the depression existing on the surface in contact with the molded product is filled with a metal film, the surface is smoothed as much as possible to obtain a molding with good surface properties. A mold can be obtained.

Further, in the recording medium according to the present invention, the substrate is formed by using a molding die whose surface is made as smooth as possible by filling the recesses present on the surface in contact with the molded product with the metal film. As a result, the substrate has good surface properties with the projections suppressed as much as possible. As a result, it is possible to obtain high reliability with good surface properties, excellent recording / reproducing characteristics, and sufficient support for further high-density recording. Recording medium.

Further, the method of manufacturing a recording medium according to the present invention is directed to a method of manufacturing a recording medium using a molding die whose surface is made as smooth as possible by filling a hollow portion present on a surface in contact with a molded product with a metal film. As a result, the substrate has good surface properties with the projections suppressed as much as possible, resulting in good surface properties, excellent recording / reproducing characteristics, and high reliability that can sufficiently cope with further high-density recording. The obtained recording medium can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a molding die to which the present invention is applied.

FIG. 2 is a cross-sectional view showing a recess present on a molding surface of a molding die.

FIG. 3 is a sectional view showing one step of a method for manufacturing a molding die to which the present invention is applied.

FIG. 4 is a cross-sectional view showing another step of the method for manufacturing a molding die to which the present invention is applied.

FIG. 5 is a cross-sectional view showing another step of the method for manufacturing a molding die to which the present invention is applied.

FIG. 6 is a cross-sectional view showing another step of the method for manufacturing a molding die to which the present invention is applied.

FIG. 7 is a cross-sectional view showing a main part of a molding die obtained by a method of manufacturing a molding die to which the present invention is applied.

8 is a cross-sectional view showing a main part of a disk substrate formed by using a molding die to which the present invention is applied, which is manufactured by the process of FIG. 7;

FIG. 9 is a sectional view of a main part of an injection molding apparatus provided with a molding die to which the present invention is applied.

FIG. 10 is a sectional view showing a magnetic disk as an example of a recording medium to which the present invention is applied.

FIG. 11 is a sectional view showing a magnetic disk as another example of the recording medium to which the present invention is applied.

FIG. 12 is a perspective view showing the magnetic disk shown in FIG. 11;

13 is a cross-sectional view showing one step of a manufacturing process of a molding die for molding the disk substrate of the magnetic disk shown in FIG.

14 is a cross-sectional view showing another step of the manufacturing process of the molding die for molding the disk substrate of the magnetic disk shown in FIG.

15 is a cross-sectional view showing another step of the manufacturing process of the molding die for molding the disk substrate of the magnetic disk shown in FIG.

16 is a cross-sectional view showing another step of the manufacturing process of the molding die for molding the disk substrate of the magnetic disk shown in FIG.

17 is a cross-sectional view showing a main part of a molding die for molding the disk substrate of the magnetic disk shown in FIG.

18 is a fragmentary cross-sectional view showing one step of magnetizing protrusions and recesses of the magnetic film of the magnetic disk shown in FIG.

19 is a fragmentary cross-sectional view showing another step of magnetizing the protrusions and recesses of the magnetic film of the magnetic disk shown in FIG. 11;

FIG. 20 is a sectional view showing a magneto-optical disk as another example of the recording medium to which the present invention is applied.

[Explanation of symbols]

1 Mold for molding, 2 Mold substrate, 3 Mold base material,
3c recess, 6 metal film

Claims (10)

[Claims] 1. A molding die, characterized in that a dent present on a surface in contact with a molded product is filled with a metal film so as to be filled. 2. The molding die according to claim 1, wherein the resin substrate is molded by injection molding. 3. A method for manufacturing a molding die, comprising: filling a dent present on a surface in contact with a molded product by applying a metal film when manufacturing the molding die. 4. The method according to claim 3, wherein the molding die is for molding a resin substrate by injection molding. 5. A recording medium in which at least a recording film is formed on a substrate, wherein the substrate has a molding metal formed by filling a hollow portion present on a surface in contact with a molded product by applying a metal film. A recording medium characterized by being formed using a mold. 6. The substrate according to claim 5, wherein the substrate is formed by injection molding using the molding die.
The recording medium according to the above. 7. The recording medium according to claim 5, wherein the substrate has a predetermined pattern of irregularities. 8. A substrate is formed using a molding die in which a hollow portion present on a surface in contact with a molded product is filled with a metal film, and at least a recording film is formed on the substrate. A method for manufacturing a recording medium, comprising: 9. The method for manufacturing a recording medium according to claim 8, wherein the substrate is formed by injection molding using the molding die. 10. The method according to claim 1, wherein a predetermined pattern of irregularities is formed on a surface of the molding die in contact with the molded product, and a substrate on which the predetermined pattern of irregularities is transferred is molded using the molding die. The method for manufacturing a recording medium according to claim 8, wherein