JP2003173513A - Magnetic transfer master carrier and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To carry out good magnetic transfer on a perpendicular magnetic recording medium. <P>SOLUTION: A master carrier 3 comprises a soft magnetic layer having a height (d) and a track direction width (w) on the projected surface of a substrate 3a having a pattern projected part in accordance with information to be transferred, and a soft magnetic layer formed in a recess between the projected parts of the substrate 3a to be magnetically coupled with the soft magnetic layer on the projected surface. By using the master carrier 3, in a state where a projected part constituted of the soft magnetic layer 3b of the master carrier 3 is bonded to the magnetic recording surface 2b of the magnetic recording medium 2, a transfer magnetic field Hdu directed from the substrate 3a side of the master carrier 3 to the soft magnetic layer 3b side is applied to execute magnetic transfer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic transfer master carrier provided with a pattern of convex portions for transferring information to a magnetic recording medium, and more particularly to transferring information to a perpendicular magnetic recording medium. The present invention relates to a magnetic transfer master carrier.

The present invention also relates to a method for producing a master carrier for magnetic transfer for transferring information to the perpendicular magnetic recording medium of the present invention.

[0003]

2. Description of the Related Art In general, a magnetic recording medium has a so-called high-speed access, which is a large capacity for recording a large amount of information with a large amount of information, is inexpensive, and can read a necessary portion preferably in a short time. A possible medium is desired. A high-density magnetic recording medium (magnetic disk medium) used in a hard disk device or a flexible disk device is known as an example thereof, and in order to realize a large capacity, a magnetic head accurately scans a narrow track width,
A so-called tracking servo technique, which reproduces a signal with a high S / N ratio, plays a major role. In order to perform this tracking servo, a servo signal for tracking, an address information signal, a reproduction clock signal, etc. are recorded at a certain interval in the disc as a so-called preformat.

As a method of accurately and efficiently performing this pre-formatting, a magnetic transfer method of magnetically transferring information such as a servo signal carried by a master carrier to a magnetic recording medium is disclosed in Japanese Patent Laid-Open No. 63-183623. Kaihei 10-4
It is disclosed in Japanese Patent Laid-Open No. 0544 and Japanese Patent Laid-Open No. 10-269566.

In this magnetic transfer, a master carrier having a concavo-convex pattern (patterned convex portion) corresponding to information to be transferred to a magnetic recording medium (slave medium) such as a magnetic disk medium is prepared. By applying a transfer magnetic field with the medium in close contact, a magnetic pattern corresponding to information (for example, servo signal) carried by the concavo-convex pattern of the master carrier is transferred to the slave medium. You can record statically without changing the relative position with
It has the advantage that accurate preformat recording is possible and the time required for recording is extremely short.

[0006]

By the way, as a magnetic recording medium, an in-plane magnetic recording medium having an easy axis of magnetization in the plane of its magnetic layer and an easy axis of magnetization in the direction perpendicular to the plane of the magnetic layer are provided. Although a perpendicular magnetic recording medium having the same can be considered, an in-plane magnetic recording medium has been generally used in the past, and the development of the above-mentioned magnetic transfer technique has been advanced mainly for magnetic transfer to the in-plane magnetic recording medium. On the other hand, if the perpendicular magnetic recording medium is used, it is expected that the capacity will be further increased as compared with the in-plane magnetic recording medium.

When performing magnetic transfer to a perpendicular magnetic recording medium, it is necessary to apply a magnetic field in a direction perpendicular to the surface of the magnetic layer, and it is considered that there are optimum conditions different from those of the in-plane magnetic recording medium. .

For example, during magnetic transfer onto a perpendicular magnetic recording medium, there is a problem that the magnetic disorder is large at the boundary between the magnetization reversal portion and the non-reversal portion, and the signal quality is not good. The analysis by the inventors of the present invention has revealed that this is a problem caused by insufficient convergence of the magnetic flux to the magnetization reversal part, and is a cause of deterioration in signal quality.

Further, in the perpendicular magnetic transfer, the thickness of the convex portion pattern formed by the magnetic layer of the master carrier is thin, the magnetic pole distance generated by a magnetic field passing vertically through this is short (diamagnetic field), and the adjacent convex It is difficult to realize sufficient signal quality only by forming a magnetic layer having a simple form, because there is no assist that acts to converge the magnetic flux to the convex portion between the portions.

In view of the above circumstances, it is an object of the present invention to provide a magnetic transfer master carrier capable of excellent magnetic transfer to a perpendicular magnetic recording medium, and a method for producing the magnetic transfer master carrier. .

[0011]

The master carrier for magnetic transfer of the present invention comprises a convex portion having a magnetic layer on the surface, which is formed for transferring information to the magnetic layer of a perpendicular magnetic recording medium. A master carrier for magnetic transfer, wherein a magnetic layer is also formed in a concave portion between the convex portions, and the magnetic layer formed in the concave portion and the magnetic layer of the convex portion are magnetically coupled to each other. The ratio of the thickness of the magnetic layer to the track-direction width of the magnetic layer is 0.8 or more and 3 or less.

As used herein, the term "convex portion having a magnetic layer on the surface" means a portion protruding with reference to the bottom of the concave portion before the magnetic layer is formed between the concave portions, and at least the convex portion. The tip portion may be formed of a magnetic layer, and the protrusion itself may be formed of a magnetic layer.

The term "magnetically coupled" means that, when a transfer magnetic field is applied in the thickness direction of the convex portion, most of the magnetic flux passing through the magnetic layer formed in the concave portion is the convex magnetic layer. Means that the magnetic layer is continuously formed, and does not matter whether or not the magnetic layer is continuously formed.

The "track direction" corresponds to the direction along the track formed on the slave medium by magnetic transfer.

The ratio of the thickness of the magnetic layer to the width of the magnetic layer of the convex portion in the track direction is more preferably 0.9 or more and 2.5 or less.

In the magnetic transfer master carrier of the present invention, the magnetic layer of the convex portion of the magnetic transfer master carrier and the magnetic layer of the perpendicular magnetic recording medium are brought into close contact with each other, with respect to the magnetic layers. The magnetic transfer method is suitable for applying a transfer magnetic field in a direction perpendicular to the magnetic layer of the perpendicular magnetic recording medium to transfer the information to the magnetic layer of the perpendicular magnetic recording medium. Here, "close contact" includes not only a state in which the two are completely in close contact, but also a state in which they are closely arranged at a uniform interval. Specific examples of the perpendicular magnetic recording medium include disk-shaped magnetic recording media such as hard disks and flexible disks.

Further, another magnetic transfer master carrier of the present invention is provided with a pattern-shaped convex portion having a magnetic layer on the surface, which is formed for transferring information to the recording layer of the perpendicular magnetic recording medium. In the magnetic transfer master carrier, the magnetic layer is formed while applying a magnetic field in a direction perpendicular to the substrate surface.

At this time, it is desirable that the direction of applying the magnetic field at the time of forming the magnetic layer is substantially parallel to the direction of applying the magnetic field for transfer at the time of magnetic transfer, and the direction may be the same direction or the opposite direction.

In this magnetic transfer master carrier, perpendicular magnetic anisotropy is imparted by applying a magnetic field during formation so that the easy axis of magnetization of the magnetic layer is substantially perpendicular to the surface of the master carrier. Is desirable.

Still another magnetic transfer master carrier of the present invention has a pattern-shaped convex portion having a magnetic layer on the surface, which is formed for transferring information to the magnetic layer of the perpendicular magnetic recording medium. A magnetic transfer master carrier provided with the second magnetic material having an easy axis of magnetization parallel to the easy axis of the magnetic layer between the protrusions and having a coercive force larger than the coercive force of the magnetic layer. It is characterized in that layers are arranged.

At this time, the second magnetic layer has only to be provided between the convex portions, and may be arranged so as to fill the entire concave portion between the convex portions, or the concave portion between the convex portions. It may be provided only in part.

It is desirable that the second magnetic layer be magnetized in the vertical direction and in the direction opposite to the transfer magnetic field in advance. Here, the vertical direction means that it is perpendicular to the surface of the master carrier. That is, the easy axes of magnetization of the magnetic layer and the second magnetic layer are substantially perpendicular to the plane of the master carrier, which means that the second magnetic layer is magnetized in advance in that direction.

The coercive force of the second magnetic layer is preferably about twice the coercive force of the magnetic layer of the perpendicular magnetic recording medium.

In each of the magnetic transfer master carriers of the present invention, the magnetic layer on the surface of the convex portion is preferably soft magnetic or semi-hard magnetic.

Alternatively, in each of the magnetic transfer master carriers of the present invention, the magnetic layer on the surface of the convex portion has a coercive force of 1/3 or less of the coercive force of the magnetic layer of the perpendicular magnetic recording medium. Is desirable.

Further, as the information, for example, a servo signal is suitable.

The method for producing a master carrier for magnetic transfer of the present invention is for magnetic transfer having a patterned convex portion having a magnetic layer on the surface for transferring information to the magnetic layer of a perpendicular magnetic recording medium. A method for producing a master carrier, characterized in that the magnetic layer is formed while applying a magnetic field in a direction perpendicular to the surface.

In the method for producing a magnetic transfer master carrier of the present invention, it is desirable that the magnetic field application direction during the magnetic layer formation be substantially parallel to the transfer magnetic field application direction during the magnetic transfer.

[0029]

According to the master carrier of the present invention, the ratio R of the sectional height of the magnetic layer of the convex portion (that is, the thickness of the magnetic layer) to the width of the convex portion in the track direction is set to 0.8 or more and 3 or less. It is possible to improve the signal quality by enhancing the effect of absorbing magnetic flux into the magnetic layer on the surface of the convex portion, prevent signal omission, and perform good magnetic transfer to the perpendicular magnetic recording medium. When the ratio R is smaller than 0.8, the demagnetizing field generated in the magnetic layer when a transfer magnetic field in the height direction of the cross section is applied becomes large, and the magnetic flux is not sufficiently absorbed in the magnetic layer to deteriorate the signal quality. On the other hand, when the ratio R is larger than 3, the magnetic layer on the surface of the convex portion is significantly damaged, and further, the defective pieces cause poor adhesion and magnetic transfer failure due to signal loss due to the damage.

By forming a magnetic layer that is magnetically coupled to the magnetic layer on the surface of the protrusions not only on the surface of the protrusions but also in the recesses between the protrusions, the surface of the protrusions when a magnetic field for transfer is applied. The magnetic flux can be easily absorbed into the magnetic layer, and good magnetic transfer can be performed.

If the magnetic transfer master carrier is one in which the magnetic layer in the patterned convex portion having the magnetic layer on the surface is formed by applying a magnetic field in the direction perpendicular to the substrate surface, this magnetic field Since the perpendicular magnetic anisotropy is imparted to the magnetic layer itself by the application, the effective magnetization amount of the magnetic layer due to the demagnetizing field at the time of applying the transfer magnetic field at the time of magnetic transfer in close contact with the slave medium becomes large. The magnetic flux on the surface of the magnetic layer can be more effectively absorbed to improve the magnetic flux converging effect, and the disturbance of the magnetization at the boundary between the magnetization reversal and non-reversal can be suppressed to improve the signal quality. Good magnetic transfer can be performed on the recording medium.

Further, the magnetic transfer master carrier has an easy axis of magnetization parallel to the easy axis of the magnetic layer between the convex portions having the magnetic layer on the surface, and a coercive force larger than the coercive force of the magnetic layer. As long as it is provided with the second magnetic layer having, when used for magnetic transfer, the second magnetic layer having a large coercive force can be used by previously magnetizing it in the opposite direction to the transfer magnetic field.
By magnetizing in this way, it is possible to enhance the effect of absorbing magnetic flux into the magnetic layer on the surface of the convex portion and improve the signal quality, and suppress the disorder of the magnetization at the boundary portion between the magnetization reversal and the non-reversal, Good magnetic transfer can be performed on the perpendicular magnetic recording medium.

If the information carried by the magnetic transfer master carrier of the present invention is used as a servo signal, the servo signal can be easily and satisfactorily transferred to the perpendicular magnetic recording medium, and the preformatted perpendicular magnetic recording medium can be efficiently used. Various manufacturing becomes possible.

While the magnetic transfer master carrier of the present invention and the perpendicular magnetic recording medium are in close contact with each other, a transfer magnetic field is applied to the perpendicular magnetic recording medium in a direction perpendicular to the track surface of the perpendicular magnetic recording medium. According to the magnetic transfer method for transferring the information, as described above, good magnetic flux is absorbed into the magnetic layer on the convex surface of the master carrier, and thus good magnetic transfer can be performed.

The perpendicular magnetic recording medium magnetically transferred by the above-mentioned magnetic transfer method using the magnetic transfer master carrier of the present invention is a medium having a good information signal, and the information signal is a servo signal. In some cases, recording and reproduction can be performed with high accuracy, especially when positioning the magnetic head.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. 1 to 4 are partial sectional views of a magnetic transfer master carrier according to an embodiment of the present invention.

FIG. 1 is a partial sectional view of a magnetic transfer master carrier according to the first embodiment. The master carrier 3 is formed in a disk shape as shown in FIG. 5 described later, and a pattern-shaped convex portion for transferring information to a slave medium is formed in a donut-shaped area surrounded by a dotted line in the figure. There is.

FIG. 1 is a partial sectional view in the circumferential direction of the disc-shaped magnetic transfer master carrier 3 shown in FIG. The master carrier 3 shown in FIG. 1 comprises a substrate 3a having a patterned convex portion on its surface, and a soft magnetic layer 3b formed on the convex portion and in the concave portion between the convex portions. The circumferential width (track-direction width) of the convex portion formed on the substrate 3a is w. The soft magnetic layer 3b formed on the surface of the convex portion of the substrate 3a has a height (thickness) d and a circumferential width w corresponding to the circumferential width of the concavo-convex pattern of the substrate 3a. here,
The ratio R of the height d and the width w of the soft magnetic layer on the surface of the convex portion of the substrate 3a
(= D / w) is 0.8 or more and 3 or less.

The soft magnetic layer formed on the convex surface of the substrate and the soft magnetic layer formed on the concave portion are magnetically coupled to each other. For example, when a magnetic field in the direction from the substrate side to the magnetic layer is applied. , The magnetic flux continuously enters the soft magnetic layer of the convex portion from the soft magnetic layer of the concave portion, so compared with the case where there is no magnetic coupling with the soft magnetic layer in the concave portion, or when there is no soft magnetic layer in the concave portion. The magnetic flux absorption effect at this convex portion is high.

As the substrate 3a of the master carrier 3, nickel, silicon, quartz plate, glass, aluminum, ceramics, synthetic resin or the like is used. Also,
As the magnetic material of the soft magnetic layer 3b, Co, Co alloy (C
oNi, CoNiZr, CoNbTaZr, etc.), Fe,
Fe alloy (FeCo, FeCoNi, FeNiMo, F
eAlSi, FeAl, FeTaN), Ni, Ni alloy (NiFe) can be used, and F is particularly preferable.
eCo and FeCoNi.

The pattern-shaped convex portions (concavo-convex pattern) of the master carrier 3 can be formed by using a stamper method used as a method for manufacturing an optical disk master, a photolithography method used in semiconductor manufacturing, or the like. The production of the master carrier will be briefly described below.

First, a photoresist is formed on a glass plate (or quartz plate) having a smooth surface by spin coating or the like,
While rotating this glass plate, a laser beam (or an electron beam) modulated in accordance with the servo signal is irradiated, and a predetermined pattern on the entire surface of the photoresist, for example, a servo signal linearly extending in a radial direction from the center of rotation to each track. The pattern corresponding to (1) is exposed on the portion corresponding to each frame on the circumference, and then the photoresist is developed to remove the exposed portion to obtain a master having an uneven shape of the photoresist. Next, based on the concavo-convex pattern on the surface of the master, plating (electroforming) is performed on this surface to produce a Ni substrate having a positive concavo-convex pattern, which is peeled from the master. This substrate is used as a master carrier as it is, or a rugged pattern is coated with a soft magnetic layer and a protective film as needed to prepare a master carrier.

Further, the above-mentioned master is plated to produce a second master, and plating is performed using this second master.
You may produce the board | substrate which has a negative uneven | corrugated pattern. Further, the second master may be plated or a resin solution may be pressed to cure it to prepare a third master, and the third master may be plated to manufacture a substrate having a positive uneven pattern. .

On the other hand, after forming a pattern of photoresist on the glass plate, etching is performed to form holes in the glass plate to obtain a master plate from which the photoresist has been removed, and the substrate is formed in the same manner as described above. May be.

As the material of the substrate made of metal, Ni, Ni alloy or the like can be used as described above, and the plating for producing this substrate is electroless plating,
Various metal film forming methods including electroforming, sputtering, and ion plating can be applied. The height of the convex portion of the substrate (depth of the concave-convex pattern) is preferably in the range of 50 to 800 nm, more preferably 80 to 600 nm. When the concavo-convex pattern is a sample servo signal, a rectangular convex portion that is longer in the radial direction than in the circumferential direction is formed. Specifically, the radial length is 0.05 to 20 μm, and the circumferential length is 0.05 to 5 μm.
Is preferable, and it is preferable to select a value in which the shape is longer in the radial direction in this range as the pattern for carrying the information of the servo signal.

The soft magnetic layer 3b is formed on the concavo-convex pattern of the substrate by using a vacuum evaporation method, a sputtering method, a vacuum film forming method such as an ion plating method, a plating method or the like. The thickness of the soft magnetic layer is preferably in the range of 50 to 500 nm, more preferably 80 to 300 nm. As described above, the ratio R of the thickness d and the width w of the soft magnetic layer on the surface of the convex portion of the substrate is set to 0.8 to 3, preferably 0.9 to 2.5.

On the soft magnetic layer on the surface of the convex portion, 5 to 5
It is preferable to provide a protective film such as diamond-like carbon (DLC) having a thickness of 30 nm, and a lubricant layer may be further provided. Further, an adhesion enhancing layer such as Si may be provided between the soft magnetic layer and the protective film. By providing a lubricant, when correcting the deviation that occurs in the contact process with the slave medium,
The deterioration of durability such as the generation of scratches due to friction is improved.

FIGS. 2, 3 and 4 are partial sectional views of magnetic transfer master carriers according to second to fourth embodiments of the present invention. The master carriers 13 and 23 shown in FIGS. 2 and 3 are the same as those of the master carrier 3 of the above-described first embodiment. Soft magnetic layer formed in the recess
It consists of 13b and 23b. In the master carrier 13 of the second embodiment shown in FIG. 2, the soft magnetic layer of the concave portion and the soft magnetic layer of the convex portion are separated from each other. Even if they are separated as described above, the same effect as in the above case can be obtained as long as the distance is such that they can be magnetically coupled.

Further, the master carrier 23 of the third embodiment shown in FIG. 3 is one in which the soft magnetic layers of the concave portion and the convex portion are formed completely continuously, contrary to the case of FIG. Of course, also in this case, the magnetic flux can be effectively absorbed into the soft magnetic layer on the surface of the convex portion.

The master carriers of the second and third embodiments can be manufactured by the same method as the master carrier of the first embodiment described above, and the thickness of the soft magnetic layer formed on the substrate at the time of manufacture is changed. You can do it.

The master carrier 33 shown in FIG. 4 comprises a flat plate-shaped substrate 33a and a soft magnetic layer 33b formed on the substrate 33a in a concavo-convex pattern. As described above, the flat substrate 33a may be used, and the same effect as in the case of the soft magnetic layer provided along the unevenness of the substrate described in FIGS. 1 to 3 by the convex portion and the concave portion of the soft magnetic layer 33b. Can be obtained. In such a master carrier 33, the soft magnetic layer 33b having the thickness d is uniformly formed on the substrate 33a, and then the soft magnetic layer 33b may be formed with irregularities by using a photolithography method or the like. Here, the thickness d of the soft magnetic layer 33b on the surface of the convex portion corresponds to the thickness from the substrate surface.

In the master carrier of each of the embodiments, the soft magnetic layers 13b and 23 on the convex portions or constituting the convex portions are formed.
The ratio R of the thickness d of b and 33b and the width w in the circumferential direction thereof is 0.8 or more and 3 or less.

Next, an embodiment of a magnetic transfer method for transferring information to a slave medium using the magnetic transfer master carrier of the present invention will be described.

FIG. 5 is a perspective view showing the slave medium 2 and the master carriers 3 and 4. The slave medium is, for example, a disk-shaped magnetic recording medium such as a hard disk or a flexible disk having a magnetic recording layer formed on both sides or one side, and particularly, the easy magnetization direction of the magnetic recording layer is perpendicular to the recording surface. It is a formed perpendicular magnetic recording medium. Further, in this embodiment, the magnetic recording layers 2b and 2c are formed on both surfaces of the disk-shaped substrate 2a, respectively.

Further, the master carrier 3 is the one shown in the first embodiment, and the pattern-shaped convex portion for the lower recording layer 2b of the slave medium 2 is formed. The master carrier 4 has a layered structure similar to that of the master carrier 3, and is formed with a pattern-shaped convex portion for the upper recording layer 2c of the slave medium 2. Taking the master carrier 3 as an example, the pattern-shaped convex portion is formed in a donut-shaped region surrounded by a dotted line in the drawing.

FIG. 6 is a diagram for explaining the basic steps of this magnetic transfer. FIG. 6 (a) is a step of applying a magnetic field in one direction to initially dc magnetize a slave medium, and FIG. 6 (b) is a master. FIG. 3C is a diagram showing a state in which the carrier and the slave medium are brought into close contact with each other and a magnetic field is applied in a direction opposite to the initial DC magnetic field, and FIG. In FIG. 6, only the lower recording layer 2b side of the slave medium 2 is shown.

As shown in FIG. 6A, an initial DC magnetic field Hin is applied to the slave medium 2 in one direction perpendicular to the track surface in advance to magnetize the magnetic recording layer 2b to the initial DC magnetization. Thereafter, as shown in FIG. 6B, the surface of the slave medium 2 on the recording layer 2b side and the surface of the convex surface of the master carrier 3 on the soft magnetic layer 3b side are brought into close contact with each other, and the track surface of the slave medium 2 is Magnetic transfer is performed by applying a transfer magnetic field Hdu in a direction perpendicular to the initial DC magnetic field Hin in a direction perpendicular to the direction. As a result, as shown in FIG. 6C, information (for example, a servo signal) according to the convex pattern of the master carrier 3 is magnetically transferred and recorded on the magnetic recording layer 2b of the slave medium 2. Although the magnetic transfer by the lower master carrier 3 to the lower recording layer 2b of the slave medium 2 has been described here, as shown in FIG. 5, the upper recording layer 2c of the slave medium 2 is also in close contact with the upper master carrier 4. Then, similarly to the lower recording layer, magnetic transfer is performed simultaneously with the lower recording layer.

Even if the concavo-convex pattern of the master carrier 3 is a negative pattern having a concavo-convex shape opposite to the positive pattern of FIG. 6, the direction of the initial magnetic field Hin and the transfer magnetic field Hdu.
Similar information can be magnetically transferred and recorded by reversing the direction of the above. It should be noted that the initial DC magnetic field and the transfer magnetic field need to adopt values determined in consideration of the coercive force of the slave medium, the relative magnetic permeability of the master carrier and the slave medium, and the like.

A disk-shaped magnetic recording medium such as a hard disk or a high-density flexible disk is used as the slave medium 2, and a coating type magnetic recording layer or a metal thin film type magnetic recording layer is formed as the magnetic recording layer thereof. . Here, a magnetic recording layer having magnetic anisotropy having an easy axis of magnetization in a direction perpendicular to the track surface is used. The magnetic material of the metal thin film magnetic recording layer is Co, Co alloy (CoPtCr, CoC).
r, CoPtCrTa, CoPtCrNbTa, CoC
rB, CoNi, etc., Fe, Fe alloys (FeCo, Fe
Pt, FeCoNi) can be used. In order to give the magnetic recording layer the necessary magnetic anisotropy, it is preferable to provide a non-magnetic underlayer under the magnetic recording layer. This non-magnetic underlayer needs to have a crystal structure and a lattice constant that match those of the magnetic recording layer.
Cr, CrTi, CoCr, CrTa, CrMo, Ni
Examples include Al, Ru, Pd, and the like. Further, in order to stabilize the perpendicular magnetization state of the magnetic layer and to improve the sensitivity at the time of recording / reproducing, it is preferable to further provide a backing layer made of a soft magnetic layer under the nonmagnetic underlayer.

The magnetic recording layer thickness is 10 nm or more and 500 nm.
It is preferably not more than 20 nm, more preferably not less than 20 nm and not more than 200 nm. The thickness of the nonmagnetic layer is preferably 10 nm or more and 150 nm or less, more preferably 20 nm or more and 80 nm or less. The backing layer thickness is 50 nm or more 20
00 nm or less is preferable, more preferably 80 nm or more 40
It is 0 nm or less.

Next, the results of a transfer accuracy experiment in magnetic transfer carried out using the above-mentioned magnetic transfer master carrier will be described.

In the following experiment, as a slave medium,
The pressure was reduced to 1.33 × 10 ^-5 Pa (10 ^-7 Torr) at room temperature using a vacuum film deposition system (Shibaura Mechatronics: S-50S Sputtering System), and then argon was introduced to 0.4 Pa (3 × 10 ^-3 T).
orr), the glass plate is heated to 200 ° C., NiFe is 300 nm as the soft magnetic backing layer, Ti is 30 nm as the non-magnetic underlayer, and CoCrP is the magnetic recording layer.
Sequentially stacked 30 nm thick with saturation magnetization Ms: 5.7T (4700Gaus
s), a 3.5-inch disk-shaped magnetic recording medium having a coercive force Hcs: 199 kA / m (2500 Oe) was prepared and used.

As the signal quality evaluation, the transfer signal of the slave medium was evaluated by an electromagnetic conversion characteristic measuring device (SS-60 manufactured by Kyodo Denshi). The head has a playback head gap of 0.
An MR head with 19 μm, reproduction track width: 2.0 μm, recording head gap: 0.4 μm, recording track width: 2.6 μm was used. The read signal was subjected to frequency decomposition with a spectrum analyzer, and the ratio C / N between the peak intensity (C) of the primary signal and the extrapolated medium noise (N) was measured. The C / N value calculated by recording / reproducing with the same head is set to 0 dB, and the relative value Δ
C / N was determined, and if this ΔC / N was −2.0 dB or more, it was evaluated as good (∘), and if less than −2.0 dB, it was evaluated as bad (×).

As a signal missing / adhesion degree evaluation, a magnetic developer solution (Sigma Marker Q manufactured by Sigma High Chemical Co.) diluted 10 times was dropped on a slave medium on which magnetic transfer was performed, and dried to develop a magnetic transfer signal pattern. Then, the evaluation was performed based on the variation amount of the signal pattern edge. Specifically, a differential interference microscope is used to randomly scale 100 on the slave medium at a magnification of 50 times.
The field of view was observed, and if signal loss was less than 5 points in 100 fields of view, it was evaluated as good (∘) and if 5 or more points were evaluated as bad (x).

The master carrier of Example 1 was subjected to lithography to have a track width of 2.5 μm, a track pitch of 3.0 μm, and a bit length of 0.5 within a range of 20 to 40 mm in the radial direction from the center of the disk.
A disk-shaped quartz substrate with a convex pattern of μm and a height of 2.5 μm is used. FeCo30at% is used as a material on the quartz substrate with a convex pattern formed by a sputtering method, and a soft magnetic layer with a thickness of 0.5 μm is formed. A layer is formed.
The sputtering conditions for forming the soft magnetic layer are 25 ° C. and Ar.
Sputtering pressure is 1.5 × 10 ^-1 Pa (1.08mTorr), input power is
It was set to 2.80 W / cm ² . The bit length of 0.5 μm corresponds to the circumferential width w of the convex portion. That is, in the master carrier of Example 1, the soft magnetic layer formed on the surface of the convex portion of the substrate had a height (thickness) d = 0.5 μm and a circumferential width w = 0.5 μm.
m, and the ratio R of both is R = 1.

The master carrier of Example 2 has the thickness of the soft magnetic layer of 1.0 μm as in Example 1, and has a height d = 1.0 μm, a circumferential width w = 0.5 μm, and a cross section of R = 2. Is to have.

The master carrier of Example 3 has the thickness of the soft magnetic layer of 1.4 μm as in Example 1, and has a height d = 1.4 μm, a circumferential width w = 0.5 μm, and a cross section of R = 2.8. Is to have.

The master carrier of Comparative Example 1 was obtained by forming a soft magnetic layer having a thickness of 0.5 μm on a flat quartz substrate and then patterning the soft magnetic layer by a lithographic technique.
Since the soft magnetic layer is formed only on the convex portion and the soft magnetic layer is not formed on the concave portion, the concave portion and the convex portion are not magnetically coupled. This master carrier has a height d = 0.5μ
m, a circumferential width w = 0.5 μm, and a cross section of R = 1.

The master carrier of Comparative Example 2 has a soft magnetic layer formed on a quartz substrate on which a convex pattern is formed as in Example 1, but has a soft magnetic layer of 0.35 μm. Height d = 0.35 μm, circumferential width w = 0.5 μm,
It has a cross section of R = 0.7.

The master carrier of Comparative Example 3 has a soft magnetic layer formed on a quartz substrate on which a concavo-convex pattern is formed in the same manner as in Example 1, but has a soft magnetic layer of 2.0 μm. D = 2.0 μm, circumferential width w = 0.5 μm, R
= 4 cross section.

Magnetic transfer was performed on the above-mentioned slave medium by using the master carriers of Examples and Comparative Examples, and the signal quality and the signal dropout / adhesion degree were evaluated, respectively.
The results are shown in Table 1.

[0072]

[Table 1] As shown in Table 1, as in Examples 1 to 3, the cross-sectional height of the magnetic layer on the convex portion of the master carrier (that is, the thickness of the magnetic layer).
And a track direction width ratio R of the convex portions is 0.8 or more and 3 or less, and a soft magnetic layer magnetically coupled to the soft magnetic layer on the convex surface is provided in the concave portion between the convex portions, the signal quality is Good results were obtained in terms of signal loss and adhesion. On the other hand, as in Comparative Examples 1 to 3, when there is no magnetic coupling between the surface of the concave portion and the convex portion, or when the ratio R is not in the range of 0.8 or more and 3 or less, the signal quality, signal dropout / adhesion degree Either one was defective.

Next, a magnetic transfer master carrier according to another embodiment of the present invention will be described with reference to the schematic sectional view of FIG.

The master carrier 53 shown in FIG. 7 comprises a substrate 51 having a patterned uneven portion on its surface, and a soft magnetic layer 52 formed on the surface of the uneven portion. And a soft magnetic layer 52b formed in the concave portion between the convex portions, and is formed while applying a magnetic field Hpr in the direction perpendicular to the surface of the substrate 51. It is a thing.

The soft magnetic layer 52 is formed by sputtering or the like while applying a magnetic field Hpr in the direction perpendicular to the surface of the substrate 51. By applying the magnetic field Hpr during the film formation, the formed soft magnetic layer 52 is oriented in the magnetic field direction and perpendicular magnetic anisotropy is imparted. That is, the easy magnetization axis of the soft magnetic layer 52 is substantially perpendicular to the surface of the master carrier 53. The application direction of the magnetic field Hpr is substantially parallel to the application direction of the transfer magnetic field Hdu (see FIG. 6) at the time of magnetic transfer, and the direction may be the same direction or the opposite direction.

By thus setting the axis of easy magnetization of the soft magnetic layer 52 substantially perpendicular to the surface of the master carrier 53, it is possible to improve the effect of absorbing the magnetic flux when the transfer magnetic field is applied.

Next, a magnetic transfer master carrier according to still another embodiment of the present invention will be described.

The master carrier 63 shown in FIG. 8 is provided with a substrate 61 having a patterned convex portion on the surface and a soft magnetic layer 62 formed on the convex portion and in the concave portion between the convex portions, and further,
The magnetic layer 65 is embedded in the concave region between the soft magnetic layers on the convex surface. Incidentally, here, the soft magnetic layer is not provided in the recess,
The magnetic layer 65 may be provided directly.

The magnetic layer 65 has an easy axis of magnetization parallel to the easy axis of the soft magnetic layer 62. This magnetic layer 65
Is previously magnetized in one direction of the easy axis of magnetization, and when a magnetic field is applied in the direction opposite to this magnetization direction, the magnetic flux is generated by the magnetic layer 65.
Of the soft magnetic layer 62b of the convex portion due to the repulsion caused by the magnetization of the
Therefore, the effect of absorbing magnetic flux to the soft magnetic layer 62b of the convex portion is high. Here, the easy magnetization directions of the soft magnetic layer 62 and the magnetic layer 65 are substantially perpendicular to the surface of the master carrier.

The material of the magnetic layer 65 is a soft magnetic layer.
It is preferable that the coercive force is larger than the coercive force of 62 and the magnetization is not reversed by the applied magnetic field during magnetic transfer,
Coercive force Hcs of magnetic layer of magnetic recording medium which is slave medium
It is suitable to have a coercive force about twice the above.

Next, a magnetic transfer method for transferring information to the slave medium 2 using the magnetic transfer master carrier 63 of this embodiment will be described.

Similar to the above-mentioned magnetic transfer method, it is carried out in a state in which the master carrier is closely contacted with or close to the upper and lower sides of the slave medium 2 to face each other.

FIG. 9 is a diagram for explaining the basic steps of this magnetic transfer, and FIG. 9A is a step of applying a magnetic field in one direction to initially dc magnetize the slave medium, FIG. 9B. Is a step of bringing the master carrier and the slave medium into close contact with each other and applying a magnetic field in a direction opposite to the initial DC magnetic field, and FIG. 7C is a diagram showing a state after magnetic transfer. In FIG. 9, only the lower recording layer 2b side of the slave medium 2 is shown.

As shown in FIG. 9A, the initial direct-current magnetic field Hin is applied to the slave medium 2 in one direction perpendicular to the track surface so as to pre-magnetize the magnetic recording layer 2b. Then, as shown in FIG. 9B, the surface of the slave medium 2 on the side of the recording layer 2b and the surface of the master carrier 63 having the magnetic layer 65 magnetized in one direction perpendicular to the surface are closely attached. Then, the transfer magnetic field Hdu is applied in the direction perpendicular to the track surface of the slave medium 2 in the direction opposite to the initial DC magnetic field Hin (this is also the direction opposite to the magnetization direction of the magnetic layer 65 of the master carrier 63). Then, magnetic transfer is performed. As a result, as shown in FIG. 9C, information (for example, servo signal) corresponding to the convex pattern of the master carrier 63 is magnetically transferred and recorded on the magnetic recording layer 2b of the slave medium 2. Here, the magnetic transfer by the lower master carrier 63 to the lower recording layer 2b of the slave medium 2 has been described, but the upper recording layer 2c of the slave medium 2 is also in close contact with the upper master carrier and is similar to the lower recording layer. Then, magnetic transfer is performed simultaneously with the lower recording layer.

As described above, by previously magnetizing the magnetic layer 65 provided in the concave portion between the convex portions of the master carrier in the direction opposite to the direction of applying the transfer magnetic field, the magnetic flux is convex when the transfer magnetic field is applied. The effect of converging to the soft magnetic layer 62 on the portion can be improved, and good magnetic transfer can be performed.

The initial DC magnetic field and the transfer magnetic field are
It is necessary to adopt a value determined in consideration of the coercive force of the slave medium, the relative magnetic permeability of the master carrier and the slave medium.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a magnetic transfer master carrier according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a magnetic transfer master carrier according to a second embodiment of the present invention.

FIG. 3 is a partial cross-sectional view of a magnetic transfer master carrier according to a third embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of a magnetic transfer master carrier according to a fourth embodiment of the present invention.

FIG. 5 is a perspective view showing a slave medium and a master carrier.

FIG. 6 is a diagram showing basic steps of a magnetic transfer method.

FIG. 7 is a partial cross-sectional view of a magnetic transfer master carrier according to another embodiment of the present invention.

FIG. 8 is a partial cross-sectional view of a magnetic transfer master carrier according to still another embodiment of the present invention.

9 is a diagram showing the basic steps of a magnetic transfer method using the magnetic transfer master carrier shown in FIG.

[Explanation of symbols]

2 Slave medium 2a substrate 2b, 2c Magnetic layer (magnetic recording layer) 3,4 Master carrier 3a, 4a substrate 3b, 4b soft magnetic layer 51 circuit board 52 Soft magnetic layer 53 master carrier 61 circuit board 62 Soft magnetic layer 63 master carrier 65 Magnetic layer

   ─────────────────────────────────────────────────── ─── Continued front page    (31) Priority claim number Japanese Patent Application No. 2001-302234 (P2001-302234) (32) Priority date September 28, 2001 (September 28, 2001) (33) Priority claiming country Japan (JP) F-term (reference) 5D006 BB07 BB08 DA02 DA03 DA04                       DA08 EA05                 5D112 AA20 DD03

Claims (11)

[Claims] 1. A master carrier for magnetic transfer, comprising a convex portion having a magnetic layer on its surface, formed for transferring information to a magnetic layer of a perpendicular magnetic recording medium, wherein the magnetic layer is the convex portion. The magnetic layer formed in the concave portion between the parts is magnetically coupled to the magnetic layer of the convex portion, and the thickness of the magnetic layer with respect to the track direction width of the magnetic layer of the convex portion. Ratio of 0.8 or more and 3 or less. 2. The master carrier for magnetic transfer according to claim 1, wherein the ratio of the thickness of the magnetic layer to the track-direction width of the magnetic layer of the convex portion is 0.9 or more and 2.5 or less. 3. A master carrier for magnetic transfer, comprising a pattern-shaped convex portion having a magnetic layer on the surface thereof, which is formed to transfer information to a magnetic layer of a perpendicular magnetic recording medium. A magnetic transfer master carrier, wherein the layer is formed while applying a magnetic field in a direction perpendicular to the surface. 4. The magnetic field application direction when the magnetic layer is formed is
4. The magnetic transfer master carrier according to claim 3, wherein the magnetic transfer master carrier is substantially parallel to a transfer magnetic field application direction during magnetic transfer. 5. The magnetic easy axis of the magnetic layer is substantially perpendicular to the surface.
The magnetic transfer master carrier described. 6. A master carrier for magnetic transfer, comprising a pattern-shaped convex portion having a magnetic layer on the surface thereof, which is formed for transferring information to a magnetic layer of a perpendicular magnetic recording medium. A magnetic transfer characterized in that a second magnetic layer having an easy axis of magnetization parallel to the easy axis of the magnetic layer and having a coercive force larger than that of the magnetic layer is disposed between the portions. Master carrier for. 7. The master carrier for magnetic transfer according to claim 6, wherein the second magnetic layer is magnetized in a direction perpendicular to the surface. 8. The magnetic transfer master according to claim 6, wherein the coercive force of the second magnetic layer is about twice the coercive force of the magnetic layer of the perpendicular magnetic recording medium. Carrier. 9. The magnetic transfer master carrier according to claim 1, wherein the information is a servo signal. 10. A method for producing a master carrier for magnetic transfer, comprising a pattern of convex portions having a magnetic layer on the surface thereof for transferring information to a magnetic layer of a perpendicular magnetic recording medium, comprising: A method for producing a master carrier for magnetic transfer, comprising forming a layer while applying a magnetic field in a direction perpendicular to the surface. 11. The method for producing a magnetic transfer master carrier according to claim 10, wherein a magnetic field application direction at the time of forming the magnetic layer is substantially parallel to a transfer magnetic field application direction at the time of magnetic transfer. .