JP2001143257A - Magnetic transfer method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transfer a transfer pattern of high quality from a master carrier to a slave medium by magnetic transfer. SOLUTION: The master carrier for magnetic transfer where a magnetic layer is formed in a part corresponding to an information signal on the surface of a substrate and a magnetic recording medium as the slave to which the pattern is to be transferred are used, and the slave medium is preliminarily initially magnetized by DC in a certain direction, and the master carrier for magnetic transfer and the slave medium initially magnetized by DC are brought into close contact with each other, and a magnetic field for transfer is applied in a certain direction opposite to the direction of initial DC magnetization on the slave surface to perform magnetic transfer. In this case, a width Wm of the magnetic layer formed on the master carrier and a width Ws of magnetization on the magnetic layer of the slave medium after magnetic transfer are within a range of 0.04< (Wm-Ws)/Wm}<=0.3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic transfer method for transferring recording information to a magnetic recording medium for a magnetic recording / reproducing apparatus having a large capacity and a high recording density in a short time.
The present invention relates to a transfer method used for recording a servo signal, an address signal, and other ordinary video signals, audio signals, data signals, and the like on a high recording density magnetic recording medium.

[0002]

2. Description of the Related Art There is a demand for a large-capacity, inexpensive medium capable of reading a required portion in a short time and having a high so-called access speed, which records a large amount of coast information with an increase in the amount of information. High-density floppy disk represented by Iomega Corporation). In order to realize a large capacity, a so-called tracking servo technique that accurately scans a narrow track width with a magnetic head and reproduces a signal with good S / N plays a large role.

In a large-capacity magnetic recording medium, a tracking servo signal, an address information signal, a reproduction clock signal, and the like are recorded at intervals within one round of the disk, that is, a so-called preformat is performed. The magnetic head can read the preformatted signal and correct its own position to accurately travel on the track.

The current preformatting is performed by recording disks one by one and one track at a time using a dedicated servo recording device. Since the servo recording device is expensive and the time required for preformatting becomes longer as the capacity becomes larger,
In the production of a large-capacity magnetic recording medium, the proportion of the pre-formatting step in the production process is large, and the proportion of the pre-formatting step in the production cost is large, and there has been a demand for providing an efficient production method.

On the other hand, there has been proposed a system in which a magnetic recording medium on which a preformat has been prepared is used as a master carrier without preformatting one track at a time, and the preformat is magnetically transferred from the master carrier. For example, JP-A-63-183623, JP-A-10-4054
No. 4, JP-A-10-269566 discloses a transfer technique.

In JP-A-63-183623 and JP-A-10-40544, an uneven shape corresponding to an information signal is formed on the surface of a substrate, and a ferromagnetic thin film is formed on at least the surface of the uneven portion. The surface of the magnetic transfer master carrier is brought into contact with the surface of a sheet-shaped or disk-shaped magnetic recording medium on which a ferromagnetic thin film or a ferromagnetic powder coating layer is formed, or is further projected by applying an AC bias magnetic field or a DC magnetic field. There has been proposed a method of recording a magnetization pattern corresponding to an uneven shape on a magnetic recording medium by exciting a ferromagnetic material constituting a part surface.

In this method, the surface of the convex portion of the master carrier is brought into close contact with the magnetic recording medium to be pre-formatted, that is, the slave medium, and at the same time, the ferromagnetic material constituting the convex portion is excited, so that the slave medium has a predetermined pre-formed surface. This is a transfer method that forms a format, and can perform static recording without changing the relative position between the magnetic transfer master carrier and the slave medium. Is also very short.

FIG. 1 is a diagram for explaining a method of transferring from a magnetic transfer master carrier to a slave medium. As shown in the cross section in FIG. 1, a ferromagnetic thin film 2 is formed on a master carrier 1 for magnetic transfer, and a convex portion 3 formed according to a preformat is formed on the surface of the ferromagnetic thin film. . When an excitation magnetic field 5 is applied by bringing the protrusion 3 of the master carrier into close contact with the surface of the slave medium 4, the protrusion 3 is magnetized in that direction, and the slave medium 4 has the magnetization of the protrusion 3 of the magnetic transfer master carrier. , A recording magnetic field 6 is formed. In such a magnetic transfer method, a magnetic film is formed on a hard substrate having a high surface flatness, a photoresist is applied, and a photomask corresponding to a preformat pattern is used to perform exposure, development, etching, and the like. The master carrier is manufactured through a lithography process.

A pattern for recording a preformat signal has a size of about several μm, and is required to collectively process a large area signal. Therefore, when a fine signal is required as the format signal,
High precision and high quality were required for the photomask, exposure, development, and etching processes, and it was difficult to prepare a master carrier.

In addition, since the master carrier and the slave medium are brought into direct contact with each other to perform magnetic transfer over the entire area of the slave, uniform transfer between the master carrier and the slave medium during transfer becomes a problem. If the degree of adhesion is deteriorated, uniform signal intensity cannot be obtained over the entire transfer area, and accurate servo cannot be performed, which causes a servo follow-up error. In addition, the signal quality after magnetic transfer deteriorates due to the decrease in adhesion, and an error in signal reading may occur.

SUMMARY OF THE INVENTION The present invention provides a magnetic recording medium to be preformatted on a convex surface of a master carrier, that is, a slave medium, and simultaneously excites a ferromagnetic material constituting the convex portion by exciting the ferromagnetic material. In a transfer method for forming a predetermined preformat on a slave medium, even if the transfer method has a fine preformat pattern for high-density recording, the signal quality after magnetic transfer due to a decrease in adhesion between the master carrier and the slave medium is reduced. It is an object to provide a transfer method that does not deteriorate.

[0011]

SUMMARY OF THE INVENTION According to the present invention, a magnetic transfer master carrier having a magnetic layer formed in a portion corresponding to an information signal on the surface of a substrate and a slave medium to be transferred are tracked in advance. After the initial DC magnetization in the direction, the master carrier for magnetic transfer and the slave medium with the initial DC magnetization are brought into close contact with each other, and a transfer magnetic field is applied in a track direction opposite to the initial DC magnetization direction on the slave surface to perform magnetic transfer. In the transfer method, the width (Wm) of the magnetic layer formed on the master carrier and the magnetization width (Ws) on the magnetic layer of the slave medium after the magnetic transfer are 0.04 <｛(Wm−Ws).
/Wm)≦0.3, the use of a certain magnetic transfer method simplifies the preparation of a master carrier having a fine structure, improves the adhesion between the master carrier and the slave medium,
It has been found that signal quality can be improved.
Further, in the above magnetic transfer method, 0.06 <{(Wm−Ws) / Wm} ≦ 0.2. 0.08 <
The above magnetic transfer method, wherein {(Wm−Ws) / Wm} ≦ 0.1. When the thickness of the magnetic layer is d in the cross-sectional shape of the magnetic layer of the master carrier when viewed from a direction perpendicular to the transfer magnetic field application direction, the curvature of the corner of the magnetic layer is 1 / (5d) to 50 / d. A magnetic transfer method as described above. The above magnetic transfer method, wherein the curvature of the corner of the magnetic layer is in the range of 1 / (2d) to 30 / d in the cross-sectional shape of the magnetic layer of the master carrier as viewed from a direction perpendicular to the direction of application of the transfer magnetic field.

A magnetic transfer master carrier having a magnetic layer formed in a portion corresponding to an information signal on the surface of the substrate and a slave medium to be transferred are subjected to initial DC magnetization of the slave medium in the track direction in advance, In the magnetic transfer method in which the magnetic transfer master carrier and the initial DC magnetized slave medium are brought into close contact with each other and a transfer magnetic field is applied in a track direction opposite to the initial DC magnetization direction of the slave surface to perform magnetic transfer, the magnetic transfer is performed on the master carrier. Magnetic layer width (Wm) and magnetization width (Ws) on the magnetic layer of the slave medium after magnetic transfer.
Is within a range of 0.08 <｛(Wm−Ws) / Wm) ≦ 0.1, and the cross-sectional shape of the magnetic layer of the master carrier when viewed from a direction perpendicular to the transfer magnetic field application direction is as follows. It has been found that the magnetic transfer method in which the curvature of the portion is in the range of 1 / (2d) to 50 / d can improve the adhesion and the signal quality.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present researcher preliminarily sets a magnetic transfer master carrier having a magnetic layer formed in a portion corresponding to an information signal on the surface of a substrate and a slave medium to be transferred in the track direction. After the initial DC magnetization, a magnetic transfer is performed by applying a transfer magnetic field in a track direction opposite to the initial DC magnetization direction of the slave surface by bringing the master carrier for magnetic transfer into close contact with the slave medium having the initial DC magnetization. In the method, the width (Wm) of the magnetic layer formed on the master carrier and the width of magnetization (Ws) on the magnetic layer of the slave medium after magnetic transfer are 0.04 <｛(Wm−Ws) / W.
m) By using a certain magnetic transfer method within the range of ≦ 0.3, the production of a slave medium having a fine structure is simplified, and the adhesion between the master carrier and the slave medium can be improved, and the signal quality can be improved. The present invention has been made in view of the above. Then, by bringing the convex surface of the master carrier into close contact with the slave medium and simultaneously exciting the ferromagnetic material constituting the convex portion, accurate preformat recording can be performed in an extremely short time. I have.

In the magnetic transfer method of the present invention, the steps of forming a magnetic film on a hard substrate having a high surface flatness, applying a photoresist, and exposing, developing, and etching using a photomask corresponding to a preformat pattern. To create a master carrier. Since it is required that the preformat signal has a length of about several μm and collective processing of a large area signal is performed, if a fine signal is required as the preformat signal, a photomask and an exposure corresponding thereto are required. In addition, high precision and high quality are required for the steps of development and etching, and it is difficult to produce a master carrier, resulting in a high production cost.

Therefore, in the present invention, if it is possible to converge the magnetic field generated from the line width of the magnetic layer of the master carrier and perform magnetic transfer so that the slave signal width after transfer is smaller than the line width of the magnetic layer, the master The carrier can be easily manufactured, which is very effective in reducing the cost of the magnetic transfer method of the present invention.
Further, since the signal width line width of the magnetic layer of the master carrier can be widened, a narrow magnetic transfer to the slave medium can be realized even if the signal width line width of the magnetic layer on the master carrier is wide.

Further, in the cross section of the master carrier magnetic layer when viewed from a direction perpendicular to the transfer magnetic field application direction,
By adjusting the curvature of the corners of the magnetic layer, the magnetic field generated from the magnetic layer on which the information of the master carrier is recorded can be more converged, the in-plane magnetic field increases, the uniformity is improved, and the transfer on the slave medium is performed. It has been found that the information recorded later is smaller than the width of the magnetic layer of the master carrier. Also, by rounding the corners of the magnetic layer on the master carrier, the effect of reducing the contact area with the slave medium and improving the adhesion can be obtained.

Then, using a magnetic transfer master carrier having a magnetic layer formed in a portion corresponding to the information signal on the surface of the substrate and a slave medium to be transferred, the magnetization of the slave medium is initially DC-magnetized in the track direction in advance. When the magnetic transfer master carrier and the initial DC magnetized slave medium are brought into close contact with each other and a transfer magnetic field is applied in a track direction opposite to the initial DC magnetization direction of the slave medium surface to perform magnetic transfer, the master carrier is formed on the master carrier. It is assumed that the magnetic layer width (Wm) and the magnetization width (Ws) on the magnetic layer of the slave medium after magnetic transfer are in the range of 0.04 <{(Wm−Ws) / Wm} ≦ 0.3. This realizes high quality magnetic transfer.

Further, in the cross-sectional shape of the master carrier magnetic layer when viewed from a direction perpendicular to the transfer magnetic field application direction,
When the thickness of the magnetic layer is d, the curvature of the corner of the magnetic layer is 1 / (5
d) is preferably in the range of 50 / d, and more preferably the curvature of the corner of the magnetic layer is in the range of 1 / (2d) to 30 / d.

FIG. 2 is a view for explaining the shape of the magnetic layer of the master carrier for magnetic transfer of the present invention. FIG. 2 is a view for explaining a cross section. The transfer information recording section 7 made of a ferromagnetic thin film formed on the magnetic transfer master carrier 1 has a magnetic layer thickness d and a magnetic layer width Wm. The magnetic layer corner 8 has a curvature of 1 / (5d) in the example shown in FIG. As a result, when a transfer excitation magnetic field is applied in a state where the magnetic transfer master carrier 1 is in close contact with the slave medium 4, transfer transfer magnetization is formed in the transfer information recording portion in the portion of the magnetization width Ws. Is transferred to the slave medium. In the present invention, the magnetization width Ws is preferably
0.7Wm <Ws <0.96Wm.

Hereinafter, a method for producing the master carrier for magnetic transfer of the present invention will be described. FIG. 3 is a diagram for explaining a manufacturing process of the magnetic transfer master carrier of the present invention. FIG. 3 (A)
As shown in (1), a magnetic material is deposited on a substrate 31 having a smooth surface to form a magnetic layer 32. As the substrate, silicon,
Quartz plate, glass, non-magnetic metal or alloy such as aluminum, ceramics, synthetic resin, etc. shall be a plate-like body with a smooth surface and have resistance to processing environment such as temperature in etching and film forming process. Can be. The magnetic material is formed by a vacuum deposition method such as a vacuum deposition method, a sputtering method, or an ion plating method, or a plating method. Next, as shown in FIG. 3B, a photoresist 3 is formed on the magnetic layer 32.
3 is applied. Any photoresist can be selected and used in accordance with a process such as etching.

As shown in FIG. 3C, the photoresist 33 applied on the substrate is subjected to batch exposure or drawing exposure using a photomask corresponding to a preformat pattern, and further developed to form a photoresist. Then, a pattern 34 corresponding to the information of the preformat is formed. Next, in the etching step as shown in FIG.
A hole 35 having a predetermined depth is formed in the magnetic layer according to the pattern by an etching means corresponding to the substrate such as reactive etching, physical etching, or etching using an etching liquid.
To form The depth of the hole is a depth corresponding to the thickness of the magnetic layer formed as the transfer information recording portion. The hole that forms
It is preferable to form a hole having a uniform depth such that the bottom surface is formed by a plane parallel to the surface of the substrate.

As shown in FIG. 3E, the photoresist is removed by a lift-off method, the surface is polished, and if there are flashes, the surface is flattened, and the transfer information recording section 36 is formed. Next, as shown in FIG. 3F, the corners 37 of the transfer information recording unit 36 are rounded at a predetermined curvature. As a method of forming the curvature at the corner, the corner can be rounded by using a low concentration etching solution. For example, it can be performed using a dilute aqueous ferric chloride solution.

In the above description, at a predetermined position on the substrate,
After forming a convex portion of the transfer information recording section by forming a magnetic material, a non-magnetic material is formed or filled between the convex sections, and the surface of the transfer information recording section and the surface of the non-magnetic material section are flush with each other. good.

Examples of the magnetic material include Co and Co alloys such as CoNi, CoNbZr, CoNbZrTa and the like. Also, Fe, Fe alloy, Ni alloy,
For example, FeCo, FeNi, FeNiCo, FeTa
N, FeAlSi, FeAl, FeNi, or the like can be used. As a magnetic material, the magnetic flux density is large,
Transfer may be performed in the same direction as that of the slave medium, that is, in the in-plane direction for in-plane recording, or in the perpendicular direction for perpendicular recording.

A non-magnetic underlayer may be provided on the lower surface side of the magnetic material, that is, on the substrate side, in order to form necessary magnetic anisotropy. Thereby, the crystal structure and lattice constant of the magnetic layer can be made desired. Cr, C
rTi, CoCr, CrTa, CrMo, NiAl, R
u and the like are used. A protective film such as diamond-like carbon may be provided on the surface of the magnetic layer, and a lubricant may be further provided. More preferably, a 5 to 30 nm diamond-like carbon film and a lubricant are present as a protective film. This is because the provision of the lubricant causes friction when correcting the displacement occurring in the process of contact between the master carrier and the slave medium, and the lack of the lubricant results in insufficient durability.

[0026]

The present invention will be described below with reference to examples. Example 1 As a master carrier, an FeCo alloy (composition ratio: 70:30)
7.96 kA / m of Hc (atomic ratio)
e) An equally spaced radial line of 10 μm width from the center of a 3.5 inch disk-shaped substrate having a 200 nm thick magnetic layer of Ms28.9T (23000 Gauss) to a position of 20 mm to 40 mm in the radial direction, The interval is formed at an innermost circumferential position of 20 mm in the radial direction at an interval of 10 μmm, and the corners of the magnetic layer are rolled with a ferric chloride solution having a concentration of 0.019% by weight to form a magnetic layer having a corner curvature of 30 / d. Formed.

Hc 198.9 kA /
m (2500 Oe) disk-shaped magnetic recording medium,
The peak magnetic field strength is 397.9 kA / m (5000O
e) That is, the initial DC magnetization of the slave medium is performed using an electromagnet device so as to be twice the coercive force Hc of the slave medium. 198.9 using the device
Magnetic transfer was performed by applying a magnetic field of kA / m (2500 Oe). Evaluation was performed by the following evaluation methods, and the results are shown in Table 1.

Examples 2 and 3 A master carrier was produced in the same manner as in Example 1 except that the curvature of the corners of the magnetic layer described in Example 1 was changed to the values shown in Table 1. Then, magnetic transfer to the slave medium was performed, and evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Example 4 A master carrier was prepared in the same manner as in Example 1 except that the curvature of the corners of the magnetic layer described in Example 1 was changed to the value shown in Table 1. Magnetic transfer was performed on the slave medium, and evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Examples 5 to 8 A master carrier was prepared in the same manner as in Example 1 except that the curvature of the corners of the magnetic layer described in Example 4 was changed to the values shown in Table 1. The magnetic transfer to the slave medium was performed in the same manner as described above, and the evaluation was performed in the same manner as in Example 1. The results were shown in Table 1.
Shown in

Embodiment 9 A disk-shaped slave medium having a thickness of 75 μm was used as the slave medium described in Embodiment 1.
On a polyimide substrate having a thickness of 60 nm, CrTi (composition ratio: 80:20 atomic ratio) was formed to a thickness of 60 nm by sputtering, and a coercive force Hc of 206.9 kA / m (2600 O
e) 30 nm of CoPtCrTa film by sputtering
A master carrier was produced in the same manner as in Example 2, except that the transfer magnetic field was 206.9 kA / m (2600 Oe) using a slave medium having a magnetic layer with a thickness of Then, magnetic transfer to the slave medium was performed, and evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Example 10 As a slave medium, a magnetic recording medium for Zip100 (H
c = 127.3 kA / m (1600 Oe))
With the transfer magnetic field intensity set to 127.3 kA / m (1600 Oe), magnetic transfer was performed in the same manner as in Example 2, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Examples 1 to 10 A master carrier was prepared in the same manner as in Example 1 except that the curvature of the corner portion of the magnetic layer described in Example 4 was changed to the value shown in Table 1. Then, magnetic transfer to the slave medium was performed, and evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 11 A master carrier was produced in the same manner as in Example 9 except that the curvature of the corner portion of the magnetic layer described in Example 9 was changed to the value shown in Table 1. Magnetic transfer was performed on the slave medium, and evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 12 A master carrier was prepared in the same manner as in Example 10 except that the curvature of the corner portion of the magnetic layer described in Example 10 was changed to the value shown in Table 1. Similarly, magnetic transfer to a slave medium was performed, and evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Evaluation Method) Adhesion Characteristics An electromagnetic conversion characteristic measuring device (SS-60, manufactured by Kyodo Electronics) was used to evaluate the adhesion between the master carrier and the slave medium.
From the slave medium after transfer, head gap: 0.35
A signal is reproduced by an inductive head having a μm and a track width of 3.1 μm. Calculate the number of signal drops or dropouts observed in the envelope curve of one round of the disk, and if it is within 5 places, it will be "excellent", if it is in the range of 5 to 15 places, it will be "good", and beyond that, it will be "Not"
The adhesiveness was evaluated.

2. Measurement of Transfer Signal Quality In order to confirm the signal quality after magnetic transfer, a reproduced signal of a measuring device used for measuring the adhesion is observed, and this reproduced signal is converted to a digital oscilloscope (LC334A manufactured by LeCroy).
Fill in M), it was evaluated by the half-value width PW ₅₀ signal.
If the half width PW ₅₀ is 300 nm or less, “excellent”, 300
If it is up to 600 nm, it was evaluated as “good”, and if it was more than 600 nm, it was evaluated as “bad”.

3. Measurement of magnetic layer width (Wm) and magnetization width (Ws) Use a differential interference microscope for the magnetic layer width (Wm) formed on the master carrier and the magnetization width (Ws) on the slave medium magnetic layer after magnetic transfer. The measurement was performed. The magnification was 450 times. In particular, in the case of the slave medium, the magnetic medium after the magnetic transfer is diluted 10 times with a magnetic developer (Sigma Marker Q manufactured by Sigma High Chemical Co., Ltd.), dropped on the slave medium, dried, and developed from the magnetic transfer signal image developed. The magnetization width (Ws) was determined.

4. Measurement of fluctuation amount of magnetic transfer signal A magnetic developer (Sigma Marker Q, manufactured by Sigma High Chemical Co., Ltd.) diluted 10 times with the slave medium after magnetic transfer, dropped on the slave medium, dried, and developed magnetic transfer signal It was determined by evaluating the amount of edge variation. Ten fields of view were observed with a differential interference microscope at a magnification of 480 times, and the value obtained by subtracting the minimum line width (Ln) from the maximum line width (Lx) observed in the field of view was evaluated. If this value was 3% or less with respect to the target line width, it was determined as "excellent" if it was 3% to 5%, and "good" if it was more than 3%.

[0040]

[Table 1] Wm Ws (Wm-Ws) / Wm Thickness d Curvature PW₅₀ (Lx-Lm) / Ws adhesion(μm) (μm) (nm) Real Example 1 10 9.5 0.05 200 30 350 (good) 3.1 (good) 6 (good) Example 2 10 9.5 0.05 200 10 290 (excellent) 1.5 (excellent) 3 (excellent) Example 2 10 8 0.2 200 1/2 290 (excellent) 1.5 (excellent) 3 (excellent) Example 3 10 9 0.1 200 1/3 285 (excellent) 2.0 (excellent) 1 (excellent) Example 4 10 7 0.3 200 1/4 280 (excellent) 2.3 (excellent) (Excellent) 3 (excellent) Example 5 5 4.7 0.06 200 30 295 (excellent) 2.2 (excellent) 7 (good) Example 6 5 4.5 0.1 200 10 289 (excellent) 1.8 (excellent) 4 (excellent) Example 7 5 4 0.2 200 1/2 284 (excellent) 2.1 (excellent) 2 (excellent) Example 8 5 3.5 0.3 200 1/3 279 (excellent) 3.3 (excellent) 2 (excellent) Example 9 10 8 0.2 200 1/3 284 (excellent) 2.5 (excellent) 1 (excellent) Example 10 10 7 0.3 200 1/3 295 (excellent) 2.6 (excellent) 5 (excellent) Comparative Example 1 10 10 0 200 100 380 (good) 4.2 (good) 25 (bad) Comparative Example 2 10 9.9 0.01 200 60 381 (good) 3.6 (good) 20 (bad) Comparative Example 3 10 9.7 0.03 200 1/10 375 (good) 3.1 (good) 22 (bad) Comparative Example 4 10 6 0.4 200 1/15 550 (good) 5.1 (bad) 25 (bad) Comparative Example 5 10 2 0.8 200 1/20 612 (bad) 6.1 ( (Not good) 16 (not good) Comparative Example 6 5 5 0 200 100 385 (good) 3.5 (good) 31 (not good) Comparative Example 7 5 4.97 0.006 200 60 390 (good) 8.1 (bad) 29 (bad) Comparative Example 8 5 4.9 0.02 200 1/10 380 (good) 4.9 (good) 25 (bad) Comparative Example 9 5 3 0.4 200 1/15 600 (bad) 3.5 (good) 15 (good) Comparative Example 10 5 1.5 0.7 200 1/20 650 (bad) 3.8 (good) 12 (good) Comparative Example 11 10 2.3 0.77 200 1/18 620 (bad) 3.1 (good) 5 (good) Comparative Example 12 10 2 0.8 200 1/20 610 (bad) 2.9 (good) (Excellent) 9 (good)

[0041]

By using the magnetic transfer master carrier of the present invention, a transfer pattern having a high signal quality after a short time transfer to a disk-shaped medium such as a hard disk, a large-capacity removable disk medium, or a large-capacity flexible medium. Can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a method of transferring a magnetic transfer master carrier to a slave medium.

FIG. 2 is a diagram illustrating the shape of a magnetic layer of a magnetic transfer master carrier of the present invention.

FIG. 3 is a diagram illustrating a production process of the magnetic transfer master carrier of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Master carrier for magnetic transfer, 2 ... Ferromagnetic thin film, 3 ... Convex part, 4 ... Slave medium, 5 ... Excitation magnetic field, 6 ... Recording magnetic field,
7 ... transfer information recording section, 31 ... substrate, 32 ... magnetic layer, 33
... photoresist, 34 ... pattern, 35 ... hole, 36 ...
Transfer information recording portion, 37: corner portion, d: magnetic layer thickness, Wm: magnetic layer width, Ws: magnetization width

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shin Nobu 2-12-1 Ogimachi, Odawara-shi, Kanagawa Prefecture Fuji Photo Film Co., Ltd.

Claims (2)

[Claims] 1. A magnetic transfer master carrier in which a magnetic layer is formed on a portion corresponding to an information signal on a surface of a substrate, and a magnetic recording medium serving as a slave to receive a transfer. When the magnetic transfer is performed by applying the transfer magnetic field in a direction substantially opposite to the initial DC magnetization direction of the slave surface by bringing the magnetic transfer master carrier and the initial DC magnetized slave medium into close contact with each other after the DC magnetization, the master carrier is used. And the magnetization width (Ws) on the slave medium magnetic layer after magnetic transfer is 0.04 <
A magnetic transfer method, wherein {(Wm−Ws) / Wm} ≦ 0.3. 2. The curvature of the corner of the magnetic layer is 1 / (5d), where d is the thickness of the magnetic layer in the cross-sectional shape of the magnetic layer of the master carrier when viewed from a direction perpendicular to the transfer magnetic field application direction.
2. The magnetic transfer method according to claim 1, wherein the magnetic transfer method is in a range of 50 to 50 / d.