JP2003173522A - Magnetic transfer master carrier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve durability and to suppress transfer failures by increasing the adhesive force of a magnetic layer disposed on the pattern surface of the substrate of a master carrier and preventing the falling-off of the magnetic layer when the master carrier is tightly fixed to a slave medium and a transfer magnetic field is applied to carry out magnetic transfer. <P>SOLUTION: The master carrier 3 comprises a magnetic layer 32 on a pattern formed on a substrate 31, an adhesive force between the substrate 31 and the magnetic layer 32 is equal to/higher than 1×10<SP>9</SP>N/m<SP>2</SP>, the surface of the substrate 31 is oxidized, oxygen concentration Do on the surface of the magnetic layer side is reduced as a distance from the surface is larger and, with respect to oxygen concentration Dh on a pattern formation depth portion, a relation of Do>Dh is set. <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 carrying transfer information for magnetic transfer onto a slave medium.

[0002]

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 pattern composed of a plurality of convex portions having a magnetic layer on the surface thereof, which corresponds 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 master carrier and the slave medium in close contact with each other, a magnetic pattern corresponding to information (for example, servo signal) carried by the convex pattern of the master carrier is transferred to the slave medium. The advantages that static recording can be performed without changing the relative positions of the master carrier and the slave medium, accurate preformat recording is possible, and the time required for recording is extremely short. have.

The master carrier used for magnetic transfer is composed of a silicon substrate, a glass substrate or the like on which a concavo-convex pattern made of a magnetic material is formed by subjecting it to processes such as photofabrication, sputtering and etching.

Further, it has been considered to apply a lithography technique used for semiconductors or the like or a stamper producing technique used for producing an optical disk stamper to produce a magnetic transfer master carrier.

In order to improve the transfer quality in the above-mentioned magnetic transfer, it is an important subject to make the master carrier and the slave medium adhere to each other without any gap. That is, if there is poor adhesion, a region where magnetic transfer does not occur occurs, and if magnetic transfer does not occur, signal loss occurs in the magnetic information transferred to the slave medium and the signal quality deteriorates. In this case, there is a problem that the tracking function is not sufficiently obtained and the reliability is lowered.

[0008]

In the magnetic transfer described above, dust is removed at a high level because the flat master carrier presses the slave medium so as to sandwich it from one side or both sides. Must have been done. This is because if dust is present in the close contact portion, not only stable magnetic transfer cannot be performed, but also the master carrier or the slave medium itself may be damaged.

In magnetic transfer, a relatively strong pressure is applied to the master carrier and the slave medium to bring the entire surface into close contact, so that the magnetic transfer is repeated a large number of times and the number of close contacts increases, and this step causes the substrate to move. The magnetic layer formed above peels off, which is present in the close contact portion to lower the quality of the transfer signal and cause the durability of the master carrier to deteriorate.

The cause of peeling of the magnetic layer of the master carrier is caused by the magnetic layer, the magnetic layer of the slave medium, the protective layer,
It has a large chemical affinity with the lubricant layer and the brittleness of the magnetic layer itself against an external force. That is, after the master carrier is brought into close contact with the slave medium and magnetic transfer is performed,
At the time of peeling from the slave medium, a strong chemical affinity is exerted between the magnetic layer of the master carrier, which is the close contact portion, and the lubricant layer, the protective layer, and the magnetic layer of the slave medium. However, this may be repeated and peeling may occur, and in repeated use, the master carrier may be subjected to external force such as impact, so that the magnetic layer may be partially peeled or chipped.

As a method for reducing the peeling of the magnetic layer of the master carrier, a DLC film (diamond-like carbon film) is provided on the surface of the magnetic layer of the master carrier, or the uppermost layer to be the contact surface with the slave medium is used. Techniques for providing a lubricant layer and the like are disclosed in JP 2000-195048 A, JP 2001-14665 A, and the like. By providing the DLC film or the lubricant layer, peeling of the magnetic layer of the master carrier is reduced to some extent and the durability is improved, but this is not sufficient, and peeling of the magnetic layer is not completely eliminated. Further, in the conventional magnetic layer, the size of a peeled product or the like due to peeling or the like is often large. Therefore, once the peeling occurs, the peeled product or the like causes a transfer failure to deteriorate the transfer performance.

Further, when the magnetic layer is peeled off over a wide area, the missing amount of the transfer signal exceeds the allowable range and the master carrier becomes unusable. This master carrier is expensive, and how many slave media can be transferred by one master carrier is very important for suppressing the manufacturing cost.

On the other hand, even when the magnetic layer is peeled off, if the size of the peeled off area is small and the size of the peeled material or missing material is small, the effect on the transfer failure due to the missing transfer signal or poor adhesion is small. Therefore, it is considered that the transfer quality is not deteriorated and that the master carrier can be continuously used.

In view of the above circumstances, it is an object of the present invention to provide a magnetic transfer master carrier having improved durability and suppressing transfer defects.

[0015]

A first magnetic transfer master carrier of the present invention is a magnetic transfer master carrier having a magnetic layer on a pattern formed on a substrate, wherein the substrate and the magnetic layer are combined. The adhesive force is 1 × 10 ⁹ N / m ² or more, and the oxygen concentration Do of the magnetic layer side surface of the substrate decreases as the distance from the surface increases, resulting in an oxygen concentration Dh at the pattern formation depth portion. On the other hand, the relationship is Do> Dh.

The surface of the substrate on the magnetic layer side is subjected to an oxidation treatment, and the ratio of the oxygen concentration Do of the surface of the magnetic layer to the oxygen concentration Dh at the pattern formation depth portion, Dh / Do is 0.05 or more, It is preferably in the range of 0.8 or less. Further, the average oxygen concentration in the depth direction from the magnetic layer side surface of the substrate to the pattern formation depth portion is preferably 15 at% or less.

In the above magnetic transfer master carrier,
A ceramic layer is preferably provided between the substrate and the magnetic layer.

The adhesion between the substrate and the magnetic layer is 1 × 10 ⁹ N / m ²
With the above, the magnetic layer will not be peeled off even by repeated contact during magnetic transfer. As a result of examining various materials, it was found that the ceramic material is very effective for improving the adhesion. However, ceramic materials have very high internal stress. When the ceramic layer is provided on the substrate, adhesion between the magnetic layer and the ceramic layer is improved, but film peeling may occur between the ceramic layer and the substrate surface due to internal stress of the ceramic layer.
In order to improve the adhesion between the ceramic layer and the substrate, the substrate surface itself can be oxidized and the same crystalline oxide can be formed to significantly improve the adhesion, and the oxygen concentration on the substrate surface can be increased. The ceramic film thickness became thin, and film peeling due to internal stress did not occur.

The magnetic layer on the pattern of the substrate is
It is preferably soft magnetic or semi-hard magnetic.

A second magnetic transfer master carrier of the present invention is a magnetic transfer master carrier in which a pattern comprising a plurality of convex portions having a magnetic layer on at least the surface thereof is provided on a substrate. Layers are oxidised, nitrided and / or
Alternatively, it is characterized by having a carbonized portion on at least the surface.

"Having an oxidized, nitrided and / or carbonized portion ..." May have an oxidized portion, a nitrided portion and a carbonized portion at the same time. It means that any one of them may be included, or any two of them may be combined.

It is further preferable that the magnetic layer has not only the surface but also the entire area that is nitrided, oxidized, and / or carbonized.

The amount of oxidation, nitridation and / or carbonization on the surface side of the magnetic layer is larger than the amount of oxidation, nitridation and / or carbonization on the substrate side of the magnetic layer, that is, the surface side of the magnetic layer. It is desirable that the oxygen, nitrogen, and / or carbon concentration in the magnetic layer is higher than the oxygen, nitrogen, and / or carbon concentration on the substrate side. In this case, the amount of oxidation, nitridation, and / or carbonization on the surface side of the entire magnetic layer is large. It is desirable to be larger than the average value of the amount of oxidation, nitridation and / or carbonization.

The total amount of oxygen, nitrogen and / or carbon in the oxidized, nitrided and / or carbonized portion is 0.5 at% or more based on the total amount of elements in the magnetic layer, 40a.
It is desirable that t% or less, preferably 1 at% or more and 30 at% or less.

The magnetic layer on the surface of the convex portion is preferably soft magnetic or semi-hard magnetic.

[0026]

According to the first master carrier of the present invention,
Since the adhesion between the substrate and the magnetic layer is high and the oxygen concentration on the magnetic layer side surface of the substrate is high on the surface and low inside,
Even if the master carrier and the slave medium are repeatedly brought into close contact with each other under strong pressure according to magnetic transfer, the magnetic layer does not peel off, and the recording signal is not lost due to transfer failure due to the broken piece, and the transfer signal quality deteriorates. Can be suppressed, and the durability of the master carrier can be improved to increase the number of transfers.

Also, when the ceramic layer is interposed between the substrate and the magnetic layer to improve the adhesion, the substrate surface itself is subjected to an oxidation treatment to form the same crystalline oxide so as to reduce the oxygen concentration in the surface portion. By increasing the thickness, the ceramic film thickness can be reduced, and film peeling due to internal stress can be prevented.

In addition, the second master carrier of the present invention has at least the surface of the oxidized, nitrided and / or carbonized portion of the magnetic layer of the pattern having a plurality of convex portions having the magnetic layer on the surface. Therefore, the chemical affinity with the lubricant layer, the protective layer, and the surface of the magnetic layer of the magnetic recording medium that is the slave medium becomes smaller than that of the conventional one.

The oxidized, nitrided and / or carbonized portion becomes tougher than the non-oxidized magnetic layer, and the magnetic layer partially or wholly has the oxidized portion. Since the magnetic layer skeleton itself is tougher than the conventional one, it has high resistance to external force.

Further, even if peeling or chipping occurs in a part, the peeling or chipping from the oxidized, nitrided and / or carbonized magnetic layer has a small cohesive property and its size is small, which adversely affects the transfer quality. Don't give. That is, since the exfoliated material from the conventional magnetic layer has a large size, the transfer quality is remarkably deteriorated, but the exfoliated material from the magnetic layer of the master carrier of the present invention has a small size and thus the transfer quality is deteriorated. Can be suppressed.

By the above effects, the durability of the magnetic transfer master carrier can be improved and the life of the magnetic transfer master carrier can be extended, and as a result, the manufacturing cost of the magnetically transferred magnetic recording medium can be suppressed.

Oxidation, nitridation and //
Alternatively, if the amount of carbonization is made larger than the amount of oxidation, nitridation and / or carbonization on the substrate side of the magnetic layer, the amount of oxidation, nitridation and / or carbonization of the entire magnetic layer is suppressed, while the surface resistance is improved and the slave It is possible to effectively reduce the chemical affinity with the lubricant layer, the protective layer, and the magnetic layer of the medium.

If the total amount of oxygen, nitrogen and / or carbon in the oxidized, nitrided and / or carbonized portion is within the range of 0.5 to 40 at% with respect to the total amount of elements in the magnetic layer, A magnetic layer can be obtained in which the effect can be sufficiently obtained and which does not adversely affect the magnetic characteristics.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. FIG. 1 is a diagram showing steps of a magnetic transfer method using a master carrier according to one embodiment of the present invention. The form shown in FIG. 1 is an in-plane recording system. In addition, the drawing is a schematic view, and the dimensions of each part are shown in a ratio different from the actual ratio.

The outline of the magnetic transfer method by in-plane recording is as follows. First, as shown in FIG. 1A, an initial static magnetic field Hin is first applied in one direction of the track direction to a slave medium 2 having a substrate 2a and a magnetic layer (magnetic recording surface) 2b to perform initial magnetization in advance. . Thereafter, as shown in FIG. 1B, the magnetic recording surface of the slave medium 2 and the convex pattern 32a of the information carrying surface formed by coating the magnetic layer 32 on the fine concave-convex pattern of the substrate 31 of the master carrier 3. The top surface is brought into close contact, and a magnetic field for transfer Hdu is applied in the direction opposite to the initial magnetic field Hin in the track direction of the slave medium 2 to perform magnetic transfer. The magnetic field Hdu for transfer is the magnetic layer 3 of the convex pattern 32a.
As a result of being attracted to the magnetic recording medium 2, the magnetization of this portion is not reversed, and the magnetic field of the other portion is reversed. As a result, as shown in FIG. The magnetization pattern corresponding to the formation pattern of the contact convex portion pattern 32a and the concave portion space of the layer 32 is transferred and recorded.

The master carrier 3 is formed in a disc shape,
On one surface thereof, there is a transfer information carrying surface on which a fine concavo-convex pattern is formed by the magnetic layer 32 corresponding to the servo signal, and the opposite surface is held by a holder (not shown) and brought into close contact with the slave medium 2. In FIG. 1, one side 2 of the slave medium 2 is shown.
Although only b is shown, the slave medium 2 is a substrate 2a.
May have a magnetic layer on both sides, and in this case, one-sided sequential transfer is performed by closely contacting the master carriers one by one, and both sides of the slave medium 2 are closely contacted with the master carriers to perform double-sided simultaneous transfer. There are cases.

In the master carrier 3 as described above, the adhesive force between the substrate 31 and the magnetic layer 32 is 1 × 10 ⁹ N / m ² or more. Further, the surface portion of the substrate 31 is subjected to an oxidation treatment, and the distance from the surface to the bottom surface becomes large with respect to the oxygen concentration Do on the surface of the substrate 31 on the magnetic layer side (top surface of the convex portion of the concavo-convex pattern). Accordingly, the oxygen concentration becomes lower, and the oxygen concentration Dh at the pattern formation depth portion h (height of the recess bottom surface of the concavo-convex pattern) has a relationship of Do> Dh. At that time, the ratio of the oxygen concentration Do on the magnetic layer side surface to the oxygen concentration Dh at the pattern formation depth portion h, Dh / Do is 0.05 or more,
It is in the range of 0.8 or less. Furthermore, the average oxygen concentration in the depth direction from the surface of the substrate 31 to the pattern formation depth portion h is processed to be 15 at% or less.

As the above-mentioned oxidation treatment, an ion implantation method or another oxidation method by a dry process or a wet process can be adopted. For example, the surface of the substrate 31 is lightly reverse-sputtered and then exposed to a high-concentration ozone atmosphere for a certain period of time. , Near the surface is partially oxidized.

By increasing the oxygen concentration due to the oxidation of the surface portion of the substrate 31 of the master carrier 3, the adhesiveness with the magnetic layer 32 is enhanced, and the adhesive force between the substrate 31 and the magnetic layer 32 is reduced to 1
X 10 ⁹ N / m ² or more, the magnetic layer 32 does not drop out even after repeated magnetic transfer, does not become a factor of dust generation, the transfer signal quality is secured, and the durability of the master carrier 3 is improved. Increase.

Even when the concavo-convex pattern of the substrate 31 of the master carrier 3 is a negative pattern having a concavo-convex shape opposite to the positive pattern of FIG. 1, the direction of the initial magnetic field Hin and the direction of the transfer magnetic field Hdu are as described above. The same magnetization pattern can be transferred and recorded by reversing the direction.

A protective film such as diamond-like carbon (DLC) is preferably provided on the magnetic layer 32, and a lubricant layer may be provided. Also, as a protective film 5 to 3
It is further preferred that a 0 nm DLC film and a lubricant layer be present. Further, an adhesion enhancing layer such as Si may be provided between the magnetic layer 32 and the protective film. The lubricant improves deterioration of durability such as generation of scratches due to friction when correcting the deviation generated in the contact process with the slave medium 2.

As the substrate 31 of the master carrier 3, nickel, silicon, aluminum, alloy or the like is used. The concavo-convex pattern is formed by a stamper method or the like.

In the stamper method, a photoresist is formed on a glass plate (or a quartz plate) having a smooth surface by spin coating or the like, and a laser beam (or a laser beam) modulated in response to a servo signal while rotating the glass plate (or Electron beam) is applied to expose the entire surface of the photoresist with a predetermined pattern, for example, a pattern corresponding to a servo signal, on a portion corresponding to each frame on the circumference. Then, the photoresist is developed to remove the exposed portion, and a master having an uneven shape of the photoresist is obtained. Next, based on the concavo-convex pattern on the surface of the master, the surface is plated (electroformed) to form a Ni substrate having a positive concavo-convex pattern, and the Ni substrate is peeled off from the master. After subjecting this substrate to an oxidation treatment, a magnetic layer and a protective film are coated on the concavo-convex pattern to obtain a master carrier.

Further, the above-mentioned master is plated to form a second master, and plating is performed using this second master.
A substrate having a negative concavo-convex pattern may be prepared. Further, the second master may be plated or a resin solution may be pressed to cure it to form a third master, and the third master may be plated to form 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. Good.

The depth of the concavo-convex pattern on the substrate 31 (height of the protrusions) is preferably in the range of 80 nm to 800 nm, and more preferably 100 nm to 600 nm.

The magnetic layer 32 is formed by depositing a magnetic material by a vacuum deposition method such as a vacuum deposition method, a sputtering method, an ion plating method, or a plating method. As the magnetic material, Co, Co alloy (CoNi, CoNi
Zr, CoNbTaZr, etc., Fe, Fe alloy (FeC
o, FeCoNi, FeNiMo, FeAlSi, Fe
Al, FeTaN), Ni, Ni alloy (NiFe) can be used. FeCo and FeCo are particularly preferable.
It is Ni. The thickness of the magnetic layer 32 is 50 nm to 500 n.
The range of m is preferable, and more preferably 100 nm to 4
00 nm.

Also in the case of the vertical recording method, the master carrier 3 which is almost the same as the above-mentioned in-plane recording is used. In the case of this perpendicular recording, the magnetization of the slave medium 2 is preliminarily subjected to initial DC magnetization in one of the perpendicular directions, and is closely adhered to the master carrier 3 for transfer in the perpendicular direction substantially opposite to the initial DC magnetization direction. Magnetic transfer is performed by applying a magnetic field, and this transfer magnetic field is absorbed by the magnetic layer 32 of the convex pattern 32a of the master carrier 3, the perpendicular magnetization of the portion corresponding to the convex pattern 32a is reversed, and unevenness is generated. A magnetization pattern corresponding to the pattern can be recorded on the slave medium 2.

In the case of in-plane recording, the magnetic field generating means for applying the initial magnetic field and the transfer magnetic field is, for example, a ring type electromagnet device in which a coil is wound around a core having a gap extending in the radial direction of the slave medium 2. The transfer magnetic fields are arranged on both the upper and lower sides, and the transfer magnetic fields generated in the same direction in the upper and lower directions are parallel to the track direction. At the time of applying a magnetic field, the magnetic field for transferring is applied by the magnetic field generating means while rotating the contact body between the slave medium 2 and the master carrier 3. The magnetic field generating means may be provided so as to rotate. The magnetic field generating means may be arranged only on one side, or the permanent magnet device may be arranged on both sides or one side.

In the case of perpendicular recording, the magnetic field generating means arranges electromagnets or permanent magnets having different polarities above and below the closely attached body of the slave medium 2 and the master carrier 3, and generates and applies a magnetic field in the vertical direction. In the case of partially applying a magnetic field, the contact medium between the slave medium 2 and the master carrier 3 is moved or the magnetic field is moved to perform magnetic transfer of the entire surface.

Next, FIG. 2 is a sectional view of a master carrier according to another embodiment. In this embodiment, the substrate 41 of the master carrier 4 is formed by coating a thin ceramic layer 43 on an uneven pattern in advance, and a magnetic layer 42 is laminated thereon.

In the illustrated case, the ceramic layer 43 and the magnetic layer 42 are formed into a film with a predetermined thickness by sputtering or the like, and are laminated and formed on the convex top surface and the concave bottom surface of the concavo-convex pattern of the substrate 41. There is. The adhesive force between the ceramic layer 43 and the magnetic layer 42 is high, and the ceramic layer 43 and the substrate 41
(Base material) In order to enhance the adhesion to the surface, the substrate 41
The surface of the (base material) is subjected to the same oxidation treatment as described above to oxidize the surface portion, or the same crystalline oxide as the ceramic layer 43 is formed.

As a result, the ceramic layer 43 of the substrate 41 is formed.
And the magnetic layer 42 and the ceramic layer 43 and the substrate 41 (base material) have an adhesive force of 1 × 10 ⁹ N / m ^2.
That is all. Further, with respect to the oxygen concentration Do on the magnetic layer side surface (top surface of the convex portion) of the substrate 41 including the ceramic layer 43, the oxygen concentration decreases as the distance from the surface to the bottom direction increases, and the pattern formation depth portion The oxygen concentration Dh at h (bottom bottom height) has a relationship of Do> Dh.
At that time, the ratio of the oxygen concentration Do on the magnetic layer side surface to the oxygen concentration Dh at the pattern formation depth portion h, Dh / Do is 0.0.
The range is from 5 to 0.8. Further, the average oxygen concentration in the depth direction from the surface of the substrate 41 to the pattern formation depth portion h is set to 15 at% or less.

The ceramic layer 43 improves the adhesion to the magnetic layer 42. On the other hand, the ceramic layer 43 has a large internal stress, which causes the ceramic layer 43 and the substrate 4 to
Although film peeling may occur between No. 1 (base material), the adhesion was significantly improved by oxidizing the surface of the substrate 41 itself to form the same crystalline oxide. Further, by increasing the oxygen concentration on the surface of the substrate 41, the film thickness of the ceramic layer 43 could be reduced, and film peeling due to internal stress could be further prevented.

Next, FIG. 3 is a sectional view of a master carrier according to still another embodiment. In this embodiment,
As shown in FIG. 3A, the master carrier 10 has a substrate 11 having a convex pattern corresponding to information to be transferred (eg, a servo signal) on its surface, and a convex portion 11 of the convex pattern of the substrate 11.
The magnetic layer 12 is formed on both the upper surface of a and the upper surface of the recess 11b. By forming the magnetic layer 12 on the convex pattern of the substrate 11, as a result, the master carrier 10 has a pattern including a plurality of convex portions 15 having a magnetic layer on the surface thereof. The master carrier 10 is not limited to the configuration of this embodiment, and the magnetic layer may be formed only on the upper surface of the convex portion 11a of the convex pattern of the substrate. Furthermore, the convex portion itself, which is formed by patterning the convex portion made of the magnetic layer on the flat substrate surface, may be made of the magnetic layer.

The magnetic layer 12 is partially oxidized, nitrided, and / or carbonized, and the amount of this oxidation, nitridation, and / or carbonization is gradually reduced from the surface side toward the substrate side. Has been formed. Here, as an example, it is assumed that the magnetic layer 12 is only oxidized.

FIG. 3B shows the distribution of the amount of oxidation in the film thickness direction of the magnetic layer. In the partially enlarged view of the master carrier, the film thickness direction of the magnetic layer 12 of the master carrier 10 is the horizontal axis. As shown. As shown in the figure, the oxygen amount Ds on the surface side of the magnetic layer 12 is larger than the oxygen amount Dm on the substrate side,
The amount of oxygen gradually decreases from the surface side to the substrate side. The total amount of oxygen is 0.5 at for all elements in the magnetic layer.
% To 40 at% is preferable, and 1 at% to 30 at% is more preferable. Not only the magnetic layer 12 is oxidized,
In the case of having a nitriding or carbonized portion, the total amount of oxygen, nitrogen and carbon is set within the above range with respect to all the elements of the magnetic layer.

Magnetic layer 12 on substrate 11 having convex pattern
Is formed by vacuum deposition of a magnetic material, sputtering,
It can be performed using a vacuum film forming means such as an ion plating method. By introducing a reaction gas during the formation of the magnetic layer 12, a magnetic layer having an oxidized, nitrided, and / or carbonized portion can be obtained. For example, a magnetic layer having an oxidized portion can be formed by reactive sputtering using Ar mixed with an oxidizing gas (for example, oxygen) during sputtering film formation. Nitrogen is added to Ar for nitriding, and Ar to which a hydrocarbon such as methane is added may be used for carbonizing. By adjusting the gas flow rate during film formation, the oxygen amount can be easily distributed in the film thickness direction of the magnetic layer.

Alternatively, the magnetic layer may be formed by an ordinary method without using a reaction gas and then partially oxidized, nitrided and / or carbonized. In this case, a dry or wet oxidation, nitridation, or carbonization method as well as an ion implantation method can be used. For example, the surface of the magnetic layer after sputter deposition is lightly reverse-sputtered and cleaned, and then exposed to a high-concentration ozone atmosphere for a certain period of time to easily partially oxidize near the surface (for example, a region of 10 to 30 nm from the surface). You can Furthermore, the film formation by reactive sputtering and the oxidation, nitridation, or carbonization treatment after the film formation may be combined.

In the case of the magnetic transfer master carrier according to the present embodiment in which the magnetic layer is oxidized, nitrided and / or carbonized, the magnetic layer forming the convex portion is tougher than the conventional one, and therefore impact or the like is caused. It is strong against external force and has a small chemical affinity with the magnetic layer of the slave medium, so it is possible to suppress peeling of the magnetic layer during close contact peeling with the slave medium, and it can be used repeatedly for many magnetic recording media. be able to. Even if the magnetic layer on the surface of the convex portion is peeled off, the pieces such as peeled pieces are small and can be used without adversely affecting the transfer quality. Thus, the durability of the magnetic transfer master carrier can be improved and the life can be extended. As a result, the manufacturing cost of the magnetically transferred magnetic recording medium can be suppressed.

[0061]

EXAMPLES Next, the results of a durability test after repeating magnetic transfer using the examples of the magnetic transfer master carrier of the present invention will be described.

First, the production of the master carrier used as an example will be described.

As the substrate of the master carrier of the example, a Ni substrate manufactured by the stamper manufacturing method was used. Specifically, a Ni substrate was used in which a concavo-convex pattern signal having a bit length of 0.5 μm, a track width of 10 μm, and a track pitch of 12 μm was formed within a range of 20 to 40 mm in the radial direction from the center of the disk.

The oxidation treatment of the substrate surface was performed by exposing the Ni substrate to surface oxygen plasma. Here, a mixed gas of argon and oxygen was used, and the sputtering pressure was set to 1.16 Pa (8.7 mTorr) for both argon and oxygen.

Then, the magnetic layer Fe is formed on the substrate after the surface treatment.
A Co30 at% layer was formed at 25 ° C. The thickness of the magnetic layer is 200
nm, and the Ar sputtering pressure during formation by sputtering is
It was set to 1.44 × 10 ⁻¹ Pa (1.08 mTorr).

In each of Examples 1 to 3 and Comparative Examples 1 and 2, the oxygen concentration Do of the surface and the pattern formation depth region were changed by changing the exposure time and the like in the oxidation treatment of the substrate surface described above. Relationship with oxygen concentration Dh, and
The average oxygen concentration (at%) in the depth direction from the surface of the substrate to the pattern formation depth portion is different.

In the master carrier of Example 1, the ratio Dh / Do between the oxygen concentration on the surface and the oxygen concentration at the pattern formation site was
0.05, that is, Do> Dh, and a substrate surface-treated to have an average oxygen concentration of 3 at% have an adhesive force of 1.2 × 10 ⁹ between the substrate and a magnetic layer provided thereabove.
The magnetic layer is formed so as to have N / m ² .

The master carrier of Example 2 contained Dh / Do
0.7, that is, Do> Dh, and a substrate surface-treated so as to have an average oxygen concentration of 10 at% have an adhesive force of 1.2 × 10 ⁹ between the substrate and the magnetic layer provided thereon.
The magnetic layer is formed so as to have N / m ² .

The master carrier of Example 3 contained Dh / Do
0.7, that is, Do> Dh, and a substrate surface-treated so that the average oxygen concentration is 17 at%, the adhesive force between the substrate and the magnetic layer provided thereon is 1.2 × 10 ⁹
The magnetic layer is formed so as to have N / m ² .

As the master carrier of Comparative Example 1, the same substrate as that of the master carrier of Example 1 was used, and the adhesive force between the substrate and the magnetic layer provided thereon was 8.8 × 10 ⁸ N / m ^2. The magnetic layer is formed on the.

The master carrier of Comparative Example 2 was provided on a substrate surface-treated so that Dh / Do was 1, that is, Do = Dh, and the average oxygen concentration was 100 at%, on the substrate and its upper layer. Adhesion with the magnetic layer is 1.2 × 10 ⁹
The magnetic layer is formed so as to have N / m ² .

Further, as a slave medium, argon was decompressed to 1.33 × 10 ⁻⁵ Pa (1 × 10 ⁻⁴ mTorr) at room temperature with a vacuum film forming apparatus (Shibaura Mechatronics: S-50S sputtering apparatus). The aluminum plate is heated to 200 ° C. under the condition of 0.4 Pa (3 mTorr) after being introduced, and CrTi is added to 6
Saturation magnetization M
s: 5.7 T (4700 Gauss), coercive force Hcs: 199 kA / m
A (2500 Oe) 3.5-inch disk-shaped magnetic recording medium was prepared and used.

The peak magnetic field strength is 398 kA / m (5000 Oe:
Initial magnetic field magnetization of the slave medium is performed by using an electromagnet device so that the coercive force of the slave medium is twice (Hcs), and then the slave having the initial direct current magnetization is brought into close contact with the master carrier for magnetic transfer. 199kA / m (2500O
Magnetic transfer was performed by applying the magnetic field of e).

As a durability evaluation method, the contact pressure between the master carrier and the slave medium was 0.49 MPa (5.0 kgf / cm ² ), the contact and peeling were repeated 1000 times, and then the surface of the master carrier was examined by a differential interference microscope. Random 5 with 480x magnification
0 field of view is observed. In the 50 fields of view, if there are 2 or less places of wear and cracks in the magnetic layer, good magnetic transfer is possible (○), and if 3 to 5 places, magnetic transfer is possible (△), It was evaluated that the magnetic transfer accuracy was poor (x) when there were 5 or more locations.

Using the master carrier of each of the examples and comparative examples, magnetic transfer was performed on the above-mentioned slave medium, and durability was evaluated. The results are shown in Table 1.

[0076]

[Table 1] As shown in Table 1, as in Examples 1 to 3, Do> D
h, the one that satisfies the condition of the master carrier of the present invention that the adhesive force between the substrate and the magnetic layer is 1.0 × 10 ⁹ N / m ² or more is 10
It remains usable even after 00 magnetic transfer,
In particular, in Examples 1 and 2 in which the average oxygen concentrations were 3 at% and 10 at% respectively, it was found that the friction / cracking points of the magnetic layer were very few as 0 or 1 and maintained a good condition as a master carrier. . On the other hand, Comparative Examples 1 and 2 are master carriers that do not satisfy the conditions of the present invention, and wear and crack sites become 8 and 12 sites after 1000 times of magnetic transfer, and are compared with Examples 1 to 3.・ It became clear that many cracks had occurred.

[Brief description of drawings]

FIG. 1 is a diagram showing steps of a magnetic transfer method using a master carrier according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a master carrier according to another embodiment.

FIG. 3 is a sectional view of an essential part of a master carrier according to still another embodiment.

[Explanation of symbols]

2 Slave medium 2 Magnetic recording medium (slave medium) 2a support 2b Magnetic layer (recording / reproducing layer) 3, 4, 10 Master carrier for magnetic transfer 11 board 12 Magnetic layer 15 Convex part with magnetic layer on the surface 31, 41 substrate 32, 42 magnetic layer 43 Ceramic layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G11B 5/738 G11B 5/738 5/82 5/82

Claims (11)

[Claims] 1. A master carrier for magnetic transfer comprising a magnetic layer on a pattern formed on a substrate, wherein the adhesive force between the substrate and the magnetic layer is 1 × 10 ⁹ N / m ² or more, and The oxygen concentration Do on the magnetic layer side surface of the substrate decreases as the distance from the surface increases, and Do> D with respect to the oxygen concentration Dh at the pattern formation depth portion.
A master carrier for magnetic transfer characterized by having a relationship of h. 2. The master carrier for magnetic transfer according to claim 1, wherein the surface of the substrate on the magnetic layer side is oxidized. 3. The oxygen concentration Do of the magnetic layer side surface of the substrate
And a ratio of the oxygen concentration Dh at the pattern formation depth portion,
The master carrier for magnetic transfer according to claim 1 or 2, wherein Dh / Do is in a range of 0.05 or more and 0.8 or less. 4. The average oxygen concentration in the depth direction from the magnetic layer side surface of the substrate to the pattern formation depth portion is 15
The master carrier for magnetic transfer according to any one of claims 1 to 3, which is at% or less. 5. The ceramic layer is provided between the substrate and the magnetic layer.
The master carrier for magnetic transfer according to claim 1. 6. A master carrier for magnetic transfer, comprising a substrate and at least a pattern having a plurality of protrusions having a magnetic layer on the surface thereof, wherein the magnetic layer is oxidized, nitrided and / or carbonized. A master carrier for magnetic transfer, which has a portion at least on the surface. 7. The master carrier for magnetic transfer according to claim 6, wherein the magnetic layer has a nitrided, oxidized, and / or carbonized portion over the entire area. 8. The amount of oxidation, nitridation and / or carbonization on the surface side of the magnetic layer is larger than the amount of oxidation, nitridation and / or carbonization on the substrate side of the magnetic layer. Magnetic transfer master carrier. 9. The amount of oxidation, nitridation, and / or carbonization on the surface side of the magnetic layer is larger than the average value of the amounts of oxidation, nitridation, and / or carbonization of the entire magnetic layer. Magnetic transfer master carrier. 10. The total amount of oxygen, nitrogen and / or carbon in the oxidized, nitrided and / or carbonized portion is 0.5 at% or more and 40 at% with respect to the total amount of elements in the magnetic layer.
% Or less, The master carrier for magnetic transfer according to any one of claims 6 to 9 characterized by things. 11. The total amount of oxygen, nitrogen and / or carbon in the oxidized, nitrided and / or carbonized portion is 1 at% or more and 30 at% or less with respect to the total amount of elements in the magnetic layer. The master carrier for magnetic transfer according to claim 10.