JP2002203316A - Magnetic transfer medium, and magnetic transferring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic transfer medium capable of achieving both high magnetic transfer efficiency and high durability, and a magnetic transferring method. SOLUTION: The magnetic transfer medium 1 is provided with a nonmagnetic substrate 2, and a ferromagnetic layer 3 formed on the nonmagnetic substrate 2, and used as a master medium 1 when information is magnetically transferred from the master medium 1 to a slave medium 5. The surface of the ferromagnetic layer 3 is composed of a plurality of concave parts 3b, and at least one convex part 3a adjacent to the concave parts 3b. The concave parts 3b surround the at least one convex part 3a without isolation, and provided as information to be magnetically transferred.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic transfer medium and a magnetic transfer method.

[0002]

2. Description of the Related Art Hard disk drives (HDDs)
Is a fixed recording device in which a magnetic disk is irremovably mounted inside the housing. In the manufacturing process of the HDD, preformat information is written on the magnetic disk, and the HDD controls the position of the magnetic head with respect to the magnetic disk, the rotation speed of the magnetic disk, and the like using the preformat information.

For example, a ferromagnetic layer, which is a recording film of a magnetic disk, has a plurality of servo areas (servo sectors) provided so as to cross each track from the center of the disk to the periphery. Tracking servo signals are written in those servo areas. HDD
Utilizes a tracking servo signal recorded in a servo area to position a magnetic head with respect to a target position (target track) on a magnetic disk.

Conventionally, recording of a tracking servo signal on a magnetic disk has been performed using a servo signal writing device called a servo writer after a magnetic head and a magnetic disk are incorporated in the housing of an HDD. In particular,
By moving the magnetic head in the radial direction while rotating the magnetic disk, tracking servo information is sequentially written in the servo area of each track.

However, in such a method, it takes a long time to write the tracking servo information. Then, instead of using the above-mentioned method,
No. 37, JP-A-10-269566, and U.S. Pat. No. 3,869,711 have proposed using a magnetic transfer method for writing tracking servo information.

FIGS. 10A and 10B are cross-sectional views schematically showing a conventional magnetic transfer method. In the traditional way,
First, a master disk 101 shown in FIG. 10A is prepared as a magnetic transfer medium. Master disk 101
Has a structure in which a ferromagnetic layer is formed on a nonmagnetic substrate, and the ferromagnetic layer is patterned to form a convex portion on the surface of the nonmagnetic substrate. In the master disk 101 shown in FIG. 10A, these projections correspond to tracking servo information.

Next, the master disk 101 and the slave disk 105 which is a magnetic recording medium are overlapped.
The slave disk 105 is a magnetic disk mounted on the HDD, and has a structure in which a ferromagnetic layer 107 is formed on a non-magnetic substrate 106. Master disk 101
And the slave disk 105 are overlapped with each other.
Perform so that it contacts. The direction of magnetization of the ferromagnetic layer 107 is aligned in advance in the direction indicated by the arrow 111.

Thereafter, when a bias magnetic field is applied to the disks 101 and 105 in the direction indicated by the arrow 112,
Leakage magnetic field 115 is generated due to a difference in magnetic resistance between the convex portion and the concave portion of master disk 101. This leakage magnetic field 115 is transmitted to the ferromagnetic layer 107 of the slave disk 105.
, A magnetization is induced in the direction indicated by the arrow 113. As a result, the magnetization in the ferromagnetic layer 107 of the slave disk 105 becomes downward at a position corresponding to the convex portion of the master disk 101. That is, as shown in FIG.
Tracking servo information is magnetically transferred from the master disk 101 to the slave disk 105.

When the above-described magnetic transfer method is used, the time required for recording preformat information such as tracking servo information can be significantly reduced as compared with the case where a magnetic head is used. Further, preformat information can be recorded without using an expensive device such as a servo signal writing device. Further, in the servo signal writing device, it is extremely difficult to control the position of the magnetic head with high accuracy, so that the recording density is 100 Gbpsi.
It is considered impossible to write a preformat signal on a super-class magnetic disk, but it is extremely easy to manufacture a master disk with high precision compared to such control.

As described above, writing of preformat information using the magnetic transfer method is advantageous in various points as compared with the case where a servo signal writing device is used. However, there are still problems to be solved in writing preformat information using the magnetic transfer method, as described below.

In order to achieve a higher recording density in an HDD, it is essential to reduce the distance (spacing) between the magnetic head and the magnetic disk. For this purpose, it is necessary to smooth the surface of the magnetic disk by mirror finishing, for example, to achieve a surface roughness of 20 nm or less (less than the height of the glide).

However, when preformat information is recorded on a slave disk using a magnetic transfer method,
It is necessary to make all of the protrusions of the master disk completely contact the ferromagnetic layer of the slave disk. That is, the master disk and the slave disk must be brought into close contact by applying a high voltage. Therefore, in the related art, when magnetic transfer is repeatedly performed, the master disk is deteriorated, and both the master disk and the slave disk are damaged. Naturally, such a scratch is fatal to a magnetic disk that requires high smoothness as described above.

To solve such a problem, Japanese Patent Application Laid-Open No. 11-27
Japanese Patent No. 3070 describes that a hard film having a thickness of 20 nm or less is formed on a surface of a master disk provided with a convex portion. However, according to a simulation using a computer, when the magnetic pattern to be transferred becomes a micron size or less, the magnetic transfer efficiency is increased only by increasing the distance between the convex portion of the master disk and the ferromagnetic layer of the slave disk by 10 nm. Notably reduced. Therefore, in the above method of forming a hard film, although the durability of the master disk is improved, the magnetic transfer efficiency is sacrificed. in this way,
With the conventional magnetic transfer technology, it has been difficult to improve the durability of a master disk as a magnetic transfer medium while maintaining high magnetic transfer efficiency.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a magnetic transfer medium and a magnetic transfer method capable of realizing both high magnetic transfer efficiency and high durability. With the goal.

[0015]

In order to solve the above-mentioned problems, the present invention comprises a non-magnetic substrate and a ferromagnetic layer formed on the non-magnetic substrate, from a master medium to a slave medium. A magnetic transfer medium used as the master medium when magnetically transferring information, wherein the surface of the ferromagnetic layer is constituted by a plurality of concave portions and at least one convex portion adjacent to the plurality of concave portions, A magnetic transfer medium is provided, wherein a plurality of recesses are provided as the information to be magnetically transferred without enclosing each of the at least one protrusion and without isolation.

Further, according to the present invention, a magnetic field is applied to a slave medium having a first non-magnetic substrate and a first ferromagnetic layer formed on the first non-magnetic substrate to cause a magnetic field to act on the slave medium. A step of aligning the direction of magnetization of one ferromagnetic layer; a second nonmagnetic substrate; and a second ferromagnetic layer formed on the second nonmagnetic substrate. Magnetically transferring information from the master medium to the slave medium using a magnetic transfer medium in which the surface of the ferromagnetic layer includes a plurality of recesses and at least one protrusion adjacent to the plurality of recesses as a master medium; Wherein the plurality of recesses are provided as the information to be magnetically transferred without surrounding and isolating each of the at least one projection, thereby providing a magnetic transfer method.

One of the reasons that the present inventors cannot simultaneously obtain both high durability and high transfer efficiency with a conventional magnetic transfer medium is that information is recorded as convex portions on the magnetic transfer medium. I thought it was. When information is recorded as a convex portion, an extremely large pressure is applied to the convex portion because the contact area between the magnetic transfer medium and the magnetic recording medium is small. In addition, when information is recorded as protrusions, a gap is likely to occur between the magnetic transfer medium and the magnetic recording medium when they are overlaid. For this reason, it is probable that in the prior art, the protrusions of the magnetic transfer medium were easily peeled or damaged, and high durability was not obtained.

Therefore, the present inventors have found that if information is recorded as concave portions, the contact area between the magnetic transfer medium and the magnetic recording medium increases, so that the pressure applied to the convex portions can be reduced. Considering that it is possible to prevent the medium from shifting in the in-plane direction with respect to the magnetic recording medium,
Information was actually recorded as recesses on the magnetic transfer medium. As a result, when the concave portions are provided so that the island-shaped convex portions are not formed, in other words, the convex portions are not surrounded by the concave portions, the individual convex portions have a sufficiently large size. The present inventors have found that the projections can be prevented from being peeled or deteriorated remarkably, and that extremely high durability can be realized thereby, and the present invention has been accomplished.

In the present invention, the bottom surface of the above-mentioned concave portion may be formed of a ferromagnetic layer, or may be formed of a non-magnetic substrate. That is, the recesses may be depressions provided only in the surface region of the ferromagnetic layer, or may be holes penetrating the ferromagnetic layer. In the present invention, the recesses may be separated from each other, or at least some of the recesses may be connected to each other.

In the present invention, the slave medium is usually
This is a magnetic recording medium mounted on a magnetic recording device. In this case, the information is preferably preformat information used by the magnetic recording device to control at least one of a relative position and a relative speed of the magnetic head with respect to the magnetic recording medium. In an ordinary magnetic recording medium, the area occupied by the preformat information is much smaller than the area in which information is written by the user using the magnetic recording apparatus. Therefore, in this case, the contact area between the magnetic recording medium and the magnetic transfer medium can be further increased by setting the ratio of the area of the bottom surface of the concave portion to the area of the top surface of the convex portion to a smaller value, for example, 1/10 or less. .

When the ratio of the area of the upper surface of the convex portion to the area of the bottom surface of the concave portion is small, the convex portion acts like a claw. The magnetic transfer medium and the magnetic recording medium may be damaged when the medium and the magnetic recording medium are brought into close contact with each other under pressure and when the magnetic transfer medium and the magnetic recording medium are separated from each other. On the other hand, when the ratio of the area of the bottom surface of the concave portion to the area of the top surface of the convex portion is sufficiently small, the convex portion does not act like a claw, so that when aligning the magnetic transfer medium and the magnetic recording medium, It is possible to prevent the magnetic transfer medium and the magnetic recording medium from being damaged at the time of close contact under pressure and at the time of peeling.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings. In each figure,
The same or similar components are denoted by the same reference numerals, and redundant description will be omitted.

FIG. 1 is a sectional view schematically showing a magnetic transfer method according to one embodiment of the present invention. FIG. 1 illustrates a master disk 1 as a magnetic transfer medium and a slave disk 5 as a magnetic recording medium.

The master disk 1 has a structure in which a ferromagnetic layer 3 is formed on one main surface of a nonmagnetic substrate 2. The ferromagnetic layer 3 is patterned, thereby forming a convex portion 3a and a concave portion 3b. In the master disk 1, preformat information used by a magnetic recording device such as an HDD to control the relative position and relative speed of the magnetic head with respect to the slave disk 5, such as a tracking servo signal, an address information signal, and reproduction. Clock signals and the like are recorded as the concave portions 3b.

On the other hand, the slave disk 5 also has a structure in which the ferromagnetic layer 7 is formed on one main surface of the non-magnetic substrate 6. However, unlike the master disk 1, the ferromagnetic layer 7 of the slave disk 5 is not patterned and has a smooth surface.

The magnetic transfer of the preformat information from the master disk 1 to the slave disk 5 shown in FIG.
For example, the following method is used. First, slave disk 5
The direction of magnetization of the ferromagnetic layer 7 is aligned in a direction perpendicular to the substrate surface or in a direction parallel to the substrate surface. Here, assuming perpendicular recording, the direction of magnetization of the ferromagnetic layer 7 is aligned in one direction perpendicular to the substrate surface by applying a DC bias magnetic field in the direction indicated by arrow 11 to the ferromagnetic layer 7. .

Next, the slave disk 5 and the master disk 1 are overlapped so that their ferromagnetic layers 3 and 7 are in close contact with each other. As described above, the magnetic transfer efficiency is
It is greatly affected by the contact state between the protrusion 3a of the master disk 1 and the ferromagnetic layer 7 of the slave disk 5. Therefore, it is preferable that the disks 1 and 5 are superposed under a reduced pressure atmosphere, for example, under vacuum while applying a high pressure to them. At this time, the directions of magnetization of the ferromagnetic layers 3 do not have to be aligned.

Next, a bias magnetic field in a direction opposite to the direction of magnetization of the ferromagnetic layer 7, that is, in the direction shown by the arrow 12, is applied to the master disk 1 and the slave disk 5 in a state where they are superimposed. When such a bias magnetic field is applied, the convex portions 3a and the concave portions 3 of the ferromagnetic layer 3 are formed.
A leakage magnetic field is generated due to a difference in magnetic resistance between the ferromagnetic layer b and the magnetic field. on the other hand,
In a portion of the ferromagnetic layer 7 that is not in contact with the convex portion 3a, that is, in a portion corresponding to the concave portion 3b of the ferromagnetic layer 7, the magnetization is maintained downward without being reversed. As described above, the preformat information is magnetically transferred from the master disk 1 to the slave disk 5. If the slave disk is heated to an appropriate temperature when applying a bias magnetic field in the direction indicated by arrow 12, magnetic transfer can be performed more efficiently.

Now, in the master disk 1 according to the present embodiment, in addition to the preformat information being recorded as the concave portions 3b, the convex portions 3a are not surrounded by the concave portions 3b. The ferromagnetic layer 3 is formed so that does not become an island. FIG. 2 shows an example of a concavo-convex pattern formed by the convex portions 3a and the concave portions 3b.

FIG. 2A is a plan view showing an example of an uneven pattern formed by the convex portions 3a and the concave portions 3b of the master disk 1 shown in FIG. 1, and FIG. 2B is a plan view showing the master disk 1 shown in FIG. FIG. 6 is a plan view showing another example of the concavo-convex pattern formed by the convex portions 3a and the concave portions 3b. In the concavo-convex pattern shown in FIG. 2A, the plurality of recesses 3b are arranged apart from each other. Therefore, the convex portion 3a is not divided into a plurality of regions by the concave portion 3b.
Is continuous throughout. That is, FIG.
The number of the convex portions 3a forming the concave / convex pattern shown in FIG.

As described above, when the preformat information is recorded as the concave portion 3b and the size of one convex portion 3a is large, the area where the convex portion 3a is in contact with the ferromagnetic layer 7 and the one convex portion 3a is a non-magnetic material Since both areas in contact with the substrate 2 are sufficiently large, it is possible to prevent the protrusions 3a from peeling off from the non-magnetic substrate 2 during magnetic transfer. Therefore, by employing the concavo-convex pattern shown in FIG. 2A, high durability can be realized without providing a hard film on the ferromagnetic layer 3, that is, both high magnetic transfer efficiency and high durability can be achieved. It can be realized.

On the other hand, in the concavo-convex pattern shown in FIG. 2B, unlike the concavo-convex pattern shown in FIG. 2A, some of the plurality of recesses 3b are connected in series, and a pair of substantially parallel Are formed. Therefore, the protrusion 3
a is divided into three regions by a pair of linear regions formed by the concave portions 3b. That is, in the concavo-convex pattern shown in FIG. 2B, unlike the concavo-convex pattern shown in FIG. 2A, the protrusions 3 a are not continuous over the entire nonmagnetic substrate 2.

However, also in the concavo-convex pattern shown in FIG. 2B, none of the three regions formed by the convex portions 3a is surrounded by the pair of linear regions formed by the concave portions 3b (the islands). Is not formed in a shape),
It has a sufficiently large size. Therefore, FIG.
Even when the uneven pattern shown in (b) is adopted,
As in the case of employing the concavo-convex pattern shown in FIG. 2A, achieving high durability without providing a hard film on the ferromagnetic layer 3, that is, achieving both high magnetic transfer efficiency and high durability It can be realized.

In the magnetic transfer method described above, the coercive force of the ferromagnetic layer 3 must be as small as possible, for example, several hundred Oe [several hundreds × (１ ／ π) × 10 ³ A /
m] or less, and its saturation magnetization is preferably sufficiently large. It is preferable that the coercive force of the ferromagnetic layer 7 is sufficiently large.

The recess 3 b may be a depression provided only in the surface region of the ferromagnetic layer 3, or may be a hole penetrating the ferromagnetic layer 3. However, in any case, the vicinity of the opening of the recess 3b preferably has a rectangular cross section. In this case, the recording mark corresponding to the preformat information can be clearly transferred to the ferromagnetic layer 7 of the slave disk 5.

Further, the minimum value of the interval between the concave portions 3b, that is, the minimum value of the width of the convex portions 3a, is set to be equal to the opening width of the concave portion 3b.
/ 2 or more. In this case, peeling of the projection 3a can be prevented more favorably.

In the master disk 1, as the nonmagnetic substrate 2, a substrate similar to that used in a general master disk, such as a Si substrate, can be used.

The magnetic material used for the ferromagnetic layer 3 is N
Crystal materials such as i-Fe and Fe-Al-Si, Co-
Co-based amorphous materials such as Zr-Nb, Fe-based microcrystalline materials such as Fe-Ta-N, and F
Examples of the ferromagnetic material include e, Co, Fe, Fe-Co, Co-Cr, Ba, and ferrite. In addition, ordered alloy materials such as CoPt, FeCo, and FePd, which have large perpendicular magnetic anisotropy, can also be suitably used. The ferromagnetic layer 3 can be formed using a vacuum evaporation method, an ion beam sputtering method, a facing target sputtering method, or the like.

The above-mentioned master disk 1 is disclosed in
It can be manufactured by the method disclosed in Japanese Patent Application Laid-Open No. 1-273070. Hereinafter, a typical method for manufacturing the master disk 1 will be described.

In manufacturing the master disk 1,
First, a ferromagnetic layer 3 made of a ferromagnetic material is formed on a nonmagnetic substrate 2 such as a Si substrate by a sputtering method or the like. The thickness of the ferromagnetic layer 3 is, for example, about 200 nm. Next, a photosensitive resist film having a thickness of, for example, 1 μm was formed on the ferromagnetic layer 3 by using a spin coat method or the like, and the resist film was provided with openings corresponding to the convex portions 3a or the concave portions 3b. Exposure is performed using a photomask. In addition,
For the exposure of the resist film, electron beams, X-rays, near-field light, and the like can be used in addition to commonly used light such as ultraviolet light. Next, a resist pattern corresponding to the protrusions 3a is formed by developing the exposed resist film. Then, using the resist pattern as a mask, the ferromagnetic layer 3 is formed by ion milling or the like.
Is patterned. Further, the master disk 1 is obtained by removing the resist pattern.

The master disk 1 can be manufactured by a lift-off method. That is, first, a photosensitive resist film is formed to a thickness of, for example, 1.5 μm on a non-magnetic substrate 2 such as a Si substrate by a spin coating method or the like, and the resist film is formed on the convex portions 3a or the concave portions 3b. Exposure is performed using a photomask provided with a corresponding opening.
Next, a resist pattern corresponding to the concave portion 3b is formed by developing the exposed resist film. Then
The ferromagnetic layer 3 is formed on the surface of the non-magnetic substrate 2 on which the resist pattern is formed by a sputtering method or the like. Thereafter, the surface of the non-magnetic substrate 2 on which the ferromagnetic layer 3 is formed is ultrasonically cleaned in an organic solvent such as acetone to remove the resist pattern and the portion formed on the resist pattern of the ferromagnetic layer 3. Remove. As described above,
A master disk 1 can be obtained.

The master disk 1 can be manufactured by other methods. For example, nano-imprinting
The master disk 1 is obtained by forming a concave portion corresponding to information to be recorded on the non-magnetic substrate 2 by a process and forming the ferromagnetic layer 3 on the surface of the non-magnetic substrate 2 where the concave portion is formed. be able to. This method is excellent in that the concave portion 3b can be formed uniformly over a wide area.
Alternatively, the concave portion may be formed directly on the non-magnetic substrate 2 using an electron beam, X-rays, near-field light, or the like. According to this method, it takes a long time to manufacture the master disk 1. However, the time required to manufacture the master disk 1 is much less important than the time required to write the preformat information on the slave disk 5, so that a problem is caused. Will not occur.

In order to carry out the above-described magnetic transfer method,
An apparatus having the structure shown in FIGS. 3 to 5 as a main part can be used. FIG. 3 is a cross-sectional view schematically illustrating a disk holder of a magnetic transfer apparatus that can be used to perform a magnetic transfer method according to an embodiment of the present invention. FIG.
Has a support structure 32. The support structure 32 has a mounting portion 33 on which the master disk 1 is mounted such that the ferromagnetic layer 3 faces upward. Master disk 1
Above, the slave disk 5 is arranged so that its ferromagnetic layer 7 and the ferromagnetic layer 3 of the master disk 1 face each other. The positions of the master disk 1 and the slave disk 5 are fixed to the support structure 32 by being sandwiched between the mounting portion 33 and the pressing member 34.

The holding member 34 includes an elastic member 35 and the motor 3.
6 can be translated with respect to the mounting portion 33 by an actuator 37 driven by 6. The holding member 34 is provided with a window 38. The relative position of the slave disk 5 with respect to the master disk 1 can be determined with high precision by driving the actuator 37 while observing the alignment mark (not shown) formed on the back surface of the slave disk 5 with the CCD 39 through the window 38. Can be adjusted.

Note that an elastic body 40 is disposed between the mounting portion 33 and the holding member 34. The mounting portion 33 and the holding member 34 have a cooling water passage 41 for cooling the master disk 1 and the slave disk 5, and a heating wire 42 for heating the disks 1 and 5. Heating and cooling of the disks 1 and 5 are performed as necessary at the time of magnetic transfer in a magnetic field application unit described later.

FIG. 4 is a cross-sectional view schematically showing a pressing unit of a magnetic transfer apparatus that can be used to carry out a magnetic transfer method according to one embodiment of the present invention. Pressing unit 45 shown in FIG.
Has a vacuum chamber 46 for accommodating the disk holder 41 described above. The vacuum chamber 46 has a supply / exhaust port 4
7, the inside of the vacuum chamber 46 can be reduced to a desired pressure. The vacuum chamber 46
Is provided with a vertically movable arm 48 in the figure. The arm 48 increases the adhesion between the master disk 1 and the slave disk 5 by applying pressure to the pressing member 34 of the disk holder 41 housed in the vacuum chamber 46.

FIG. 5 is a view schematically showing a magnetic field applying unit of a magnetic transfer apparatus that can be used to carry out a magnetic transfer method according to one embodiment of the present invention. The magnetic field applying unit 50 has a pair of magnets 51 having different polarities.
The master disk 1 and the slave disk 5 are
After increasing the adhesion between the magnets 51, the disk holder 41 is taken out of the vacuum chamber 46 and placed between the magnets 51. Thereby, the preformat information is magnetically transferred from the master disk 1 to the slave disk 5 as described above.

As described above, the case where the vertical recording system is adopted for the slave disk 5 has been described. However, the master disk 1 can be used even when the longitudinal recording system is adopted for the slave disk 5. However, when the longitudinal recording method is adopted for the slave disk 5, an AC bias magnetic field is used for magnetic transfer instead of a DC bias magnetic field.

As described above, when magnetic transfer is performed using an AC bias magnetic field, the ferromagnetic layer 3 of the master disk 1
Usually needs to have a coercive force 2.5 to 3.0 times that of the ferromagnetic layer 7 of the slave disk 5.
Therefore, when a magnetic material having a high coercive force is used for the ferromagnetic layer 7 of the slave disk 5 to realize a storage capacity of gigabit or terabit, a magnetic material having an extremely high coercive force is used for the ferromagnetic layer 3 of the master disk 1. Must be used.

On the other hand, when the perpendicular recording method is used for the slave disk 5, that is, when magnetic transfer is performed using a DC bias magnetic field, there is no limitation as described in the case where an AC bias magnetic field is used. Therefore, in this case, a magnetic material having a low coercive force can be used for the ferromagnetic layer 7 of the slave disk 5, and accordingly,
A large storage capacity can be easily realized.

[0051]

Next, an embodiment of the present invention will be described. (Embodiment 1) FIG. 6 is a cutaway perspective view schematically showing a master disk 1 according to Embodiment 1 of the present invention. In this embodiment, as described below, a master disk 1 shown in FIG. 6 is manufactured, and its magnetic transfer efficiency and durability are examined.

First, a ferromagnetic layer 3 made of FePt and having a thickness of 0.2 μm was formed on one main surface of the nonmagnetic substrate 2 made of Si by sputtering. Next, using a photolithography technique and an etching technique, the ferromagnetic layer 3 has a circular opening and a depth of 0.2 μm.
Was formed. That is, the concave portion 3b and the convex portion 3a
And a concavo-convex pattern consisting of The recess 3b
Were formed such that openings having a diameter of 2 μm and openings having a diameter of 3 μm were spaced apart from each other and arranged alternately. Also,
The recesses 3b correspond to information to be recorded on the slave disk 5. As described above, the master disk 1 shown in FIG. 6 was manufactured.

Next, the master disk 1 manufactured by the above-described method and the separately prepared slave disk 5 are arranged in the disk holder 31 shown in FIG. 3 so that the ferromagnetic layers 3 and 7 are in contact with each other. Positioning of 1,5 was performed. The disks 1 and 5 are sandwiched between the holding member 34 and the support structure 32, and they do not shift in the in-plane direction.

Next, a pressure of 20 kg / cm ² is applied to the master disk 1 and the slave disk 5 housed in the disk holder 31 under reduced pressure for 2 seconds by the pressing unit 45 shown in FIG. Increased sex.
After that, the disk holder 31 is taken out of the vacuum chamber 46 of the pressurizing section 45, and the magnetic field applying section 50 shown in FIG.
Applied a DC magnetic field. As described above, information was magnetically transferred from the master disk 1 to the slave disk 5.

When the slave disk 5 was observed with a magnetic force microscope (MFM), a magnetic pattern corresponding to the concave portion 3b formed in the master disk 1 was well transferred to the ferromagnetic layer 7. That is, it was confirmed that the master disk 1 according to the present embodiment achieved high magnetic transfer efficiency.

The above-described magnetic transfer was performed on 20 slave disks 5 using one master disk 1. Thereafter, the ferromagnetic layer 3 of the master disk 1 was observed with a scanning electron microscope (SEM).

FIG. 7 is an SEM photograph showing a state after the magnetic transfer of the master disk 1 according to the first embodiment of the present invention has been repeated 20 times. As shown in FIG. 7, in the master disk 1 according to the present example, even after the magnetic transfer was repeated 20 times, no scratches, peeling of the projections 3a, and the like occurred.

(Comparative Example 1) The convex portion 3a and the concave portion 3 shown in FIG.
A master disk was produced in the same manner as described in Example 1, except that the relationship with b was reversed. That is, in this comparative example, not the concave portion but the convex portion was formed corresponding to the information to be recorded on the slave disk. In this comparative example, the diameter of all the convex portions was set to 2 μm.

Information was magnetically transferred from the master disk to the slave disk in the same manner as described in Example 1 except that this master disk was used, and the slave disk was observed by MFM. As a result, the magnetic pattern corresponding to the above-mentioned convex portion was not satisfactorily transferred to the ferromagnetic layer of the slave disk.

Also, using one master disk,
The magnetic transfer described above was performed on several slave disks. Thereafter, the ferromagnetic layer of the master disk was observed by SEM.

FIG. 11 is an SEM photograph showing the state after the magnetic transfer of the master disk according to Comparative Example 1 was repeated several times. In FIG. 11, a circular portion that looks dark is a portion where the convex portion has peeled off. As described above, in the master disk according to this comparative example, scratches, peeling of the convex portions, and the like were generated only by repeating magnetic transfer several times. This is because the master disk according to the present comparative example has a structure in which the individual protrusions are formed in an island shape and has a small size, so that the protrusions are easily peeled off, and the protrusions occupy more than the recesses. It is considered that this is because, when the master disk and the slave disk are brought into close contact with each other, a high pressure is applied to the convex portions and a deviation between the disks easily occurs because the area is excessively small.

When the peeling occurs at a certain convex portion as described above, the height of the convex portion is lower than the heights of the other convex portions even if the missing portion is only the upper surface of the convex portion. Become.
Therefore, in this case, it is extremely difficult to bring the upper surfaces of all the protrusions into contact with the ferromagnetic layer of the slave disk.
That is, even if the protrusion of the master disk is slightly peeled off, high magnetic transfer efficiency can no longer be realized.

(Embodiment 2) FIG. 8 is a plan view schematically showing a concavo-convex pattern formed on a master disk 1 according to Embodiment 2 of the present invention. In the present embodiment, the master disk 1 was manufactured by the same method as that described in Embodiment 1, except that the concavo-convex pattern shown in FIG. 8 was formed. In this embodiment, the concave portions 3b also correspond to information to be recorded on the slave disk 5.

Information was magnetically transferred from the master disk 1 to the slave disk 5 by the same method as that described in Embodiment 1 except that the master disk 1 was used, and the slave disk 5 was observed by MFM. . As a result, the ferromagnetic layer 7 of the slave disk 5 has the recess 3
The magnetic pattern corresponding to b was satisfactorily transferred.

Next, the durability of the master disk 1 was examined. As a result, it was possible to transfer a magnetic pattern very well until the number of repetitions of magnetic transfer was about 30 times. Further, the contour of the magnetic pattern of the slave disk 5 became slightly unclear when the number of repetitions of magnetic transfer was about 50, but good transfer could be performed up to about 300 times.

(Embodiment 3) FIG. 9 is a perspective view schematically showing a master disk 1 according to Embodiment 3 of the present invention.
The ferromagnetic layer 3 of the master disk 1 shown in FIG.
5 and a region 16. The area 15 corresponds to a preformat area in which preformat information is recorded, and includes a convex portion 3a and a concave portion 3b. On the other hand, the area 16 corresponds to a user area where information is written by the user using the magnetic recording device,
It is composed of only the projection 3a.

In this embodiment, the master disk 1 was manufactured in the same manner as described in the first embodiment, except that the concavo-convex pattern shown in FIG.
In this embodiment, the concave portions 3b also correspond to information to be recorded on the slave disk 5. Further, in the present embodiment, the concave portion 3b with respect to the total area of the upper surface of the convex portion 3a.
The ratio of the total area of the bottom surface is 1/10.

Information was magnetically transferred from the master disk 1 to the slave disk 5 in the same manner as described in Example 1 except that the master disk 1 was used, and the slave disk 5 was observed by MFM. . As a result, the ferromagnetic layer 7 of the slave disk 5 has the recess 3
The magnetic pattern corresponding to b was satisfactorily transferred.

Next, the durability of the master disk 1 was examined. As a result, the number of repetitions of magnetic transfer is 1000
Even if the number of times exceeds 3, the peeling of the projections 3a did not occur, and the magnetic pattern could be transferred very well.

Comparative Example 2 FIG. 12 is a plan view schematically showing a concavo-convex pattern formed on a master disk according to Comparative Example 2. In the concavo-convex pattern shown in FIG. 12, the convex portions 103a and the concave portions 103b are arranged in a checkered pattern. That is, in the concavo-convex pattern shown in FIG. 12, the concave portion 103b is provided so that the island-shaped convex portion 103a is formed.

In this comparative example, a master disk was manufactured in the same manner as described in Example 3 except that the concavo-convex pattern shown in FIG. 12 was formed only in the preformat area. Note that also in this comparative example, the concave portion 103b
Corresponds to information to be recorded on the slave disk. In this comparative example, the ratio of the total area of the bottom surface of the concave portion 103b to the total area of the upper surface of the convex portion 103a is 1/1.
Greater than zero.

When the durability of the master disk was examined, good transfer could not be achieved only by repeating magnetic transfer several times. Then, when the master disk after the magnetic transfer was repeated several times was observed with an SEM, many places where the protruding portions 103a were peeled off were found in the preformat region.

[0073]

As described above, according to the present invention, in a magnetic transfer medium used as a master medium when magnetically transferring information to a magnetic recording medium, in addition to providing information to be magnetically transferred as recesses, These recesses are arranged so that island-shaped protrusions are not formed. Therefore, in the present invention, the contact area between the magnetic transfer medium and the magnetic recording medium can be made sufficiently large, and the size of each projection can be made sufficiently large. Therefore, sufficient durability can be realized without protecting the surface of the projection with a hard film or the like. That is, according to the present invention, a magnetic transfer medium and a magnetic transfer method that can realize both high magnetic transfer efficiency and high durability are provided.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a magnetic transfer method according to an embodiment of the present invention.

2A is a plan view showing an example of a concavo-convex pattern formed by convex portions and concave portions of the magnetic transfer medium shown in FIG. 1, and FIG.
FIG. 3 is a plan view showing another example of the concavo-convex pattern formed by the protrusions and recesses of the magnetic transfer medium shown in FIG.

FIG. 3 is a sectional view schematically showing a disk holder of a magnetic transfer device that can be used to carry out a magnetic transfer method according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view schematically showing a pressing unit of a magnetic transfer apparatus that can be used to perform a magnetic transfer method according to one embodiment of the present invention.

FIG. 5 is a diagram schematically showing a magnetic field applying unit of a magnetic transfer device that can be used to perform a magnetic transfer method according to one embodiment of the present invention.

FIG. 6 is a cutaway perspective view schematically showing a magnetic transfer medium according to an embodiment of the present invention.

FIG. 7 is an SEM photograph showing a state after the magnetic transfer of the magnetic transfer medium according to the first embodiment of the present invention is repeated 20 times.

FIG. 8 is a plan view schematically showing a concavo-convex pattern formed on a magnetic transfer medium according to a second embodiment of the present invention.

FIG. 9 is a perspective view schematically showing a magnetic transfer medium according to a third embodiment of the present invention.

10A and 10B are cross-sectional views schematically showing a conventional magnetic transfer method.

FIG. 11 is an SEM photograph showing a state after magnetic transfer of the magnetic transfer medium according to Comparative Example 1 is repeated several times.

FIG. 12 is a plan view schematically showing a concavo-convex pattern formed on a magnetic transfer medium according to Comparative Example 2.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic transfer medium; 2 ... Nonmagnetic substrate; 3 ... Ferromagnetic layer; 3a ... Convex part; 3b ... Concave part; 5 ... Magnetic recording medium;
6: non-magnetic substrate; 7: ferromagnetic layer; 11: arrow;
12 arrow; 15 area; 16 area; 31 disk holder; 32 support structure; 33 mounting portion;
... holding member; 35 ... elastic member; 36 ... motor;
... actuator; 38 ... window; 39 ... CCD; 4
0: elastic body; 41: cooling water channel; 42: heat wire; 45
... Pressure section; 46 ... Vacuum chamber; 47 ... Supply / exhaust port;
48: arm; 50: magnetic field applying unit; 51: magnet; 101: master disk; 113: arrow;
03a: convex portion; 103b: concave portion 105: slave disk; 106: non-magnetic substrate; 107: ferromagnetic layer;
111 arrow; 112 arrow; 115 leakage magnetic field;

Claims (5)

[Claims] 1. A magnetic transfer device comprising a non-magnetic substrate and a ferromagnetic layer formed on the non-magnetic substrate, wherein the magnetic transfer is used as the master medium when magnetically transferring information from a master medium to a slave medium. A medium, wherein a surface of the ferromagnetic layer includes a plurality of recesses and at least one protrusion adjacent to the plurality of recesses, and the plurality of recesses surround each of the at least one protrusion and are isolated. A magnetic transfer medium provided as the information to be magnetically transferred without being converted. 2. The magnetic transfer medium according to claim 1, wherein the plurality of recesses are separated from each other. 3. The magnetic transfer medium according to claim 1, wherein at least some of the plurality of recesses are connected to each other. 4. The information recording medium according to claim 1, wherein the slave medium is a magnetic recording medium mounted on a magnetic recording apparatus, and the information controls at least one of a relative position and a relative speed of the magnetic head of the magnetic recording apparatus with respect to the magnetic recording medium. The magnetic transfer medium according to any one of claims 1 to 3, wherein the magnetic transfer medium is preformat information to be used for: 5. A method for applying a magnetic field to a slave medium comprising a first non-magnetic substrate and a first ferromagnetic layer formed on the first non-magnetic substrate, wherein the first ferromagnetic layer Aligning the magnetization directions of the layers, comprising: a second non-magnetic substrate; and a second ferromagnetic layer formed on the second non-magnetic substrate. Magnetically transferring information from the master medium to the slave medium using a magnetic transfer medium having a surface having a plurality of recesses and at least one protrusion adjacent to the plurality of recesses as a master medium, A magnetic transfer method, wherein a plurality of concave portions are provided as the information to be magnetically transferred without surrounding and isolating each of the at least one convex portion.