JP2004348853A - Master carrier for magnetic transfer and magnetic transfer method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance durability of a master carrier and to suppress a transfer defect at the time of magnetic transfer by preventing lack of a magnetic layer provided on the substrate of the master carrier for magnetic transfer. <P>SOLUTION: A semi-intermediate layer 32 consisting of an oxide, a nitride and/or a carbide and an intermediate layer 33 consisting of at least one of Si, B, Al, Ti, Cr, V, Ni, Cu, Fe, Co, Gd, Sm, and Nd are provided from the side of the substrate 31 between the substrate 31 and the magnetic layer 34. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

表１に示すとおり、本発明の実施例である実施例１〜１０については、パターン破損による欠陥数および信号品位いずれについても可以上の結果が得られたが、一方、比較例１および２については、パターン破損による欠陥数もしくは信号品位の少なくともいずれかで不良の評価となった。
【図面の簡単な説明】
【図１】磁気転写用マスター担体の表面の一部斜視図
【図２】図１の磁気転写用マスター担体の断面図
【図３】マスター担体とスレーブ媒体とを示す斜視図
【図４】磁気転写装置の概略構成を示す斜視図
【図５】面内磁気記録媒体への磁気転写方法の基本工程を示す図
【図６】本発明の第２の実施形態に係る磁気転写用マスター担体の一部断面図
【図７】実施例における準中間層厚みの定め方を説明するための図
【符号の説明】
１ 磁気転写装置
２ スレーブ媒体
２ｂ，２ｃ 記録面
３，４ マスター担体
１０ 転写ホルダー
２１ スレーブ媒体の基板
２２ スレーブ媒体の磁気記録層（磁性層）
３１ 基板
３２ 準中間層
３３ 中間層
３４ 磁性層
５０ 電磁石装置
５５ 磁界印加手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic transfer master carrier having a concavo-convex pattern corresponding to information to be magnetically transferred to a slave medium, and a magnetic transfer method using the master carrier.
[0002]
[Prior art]
In general, with the increase in the amount of information, a magnetic recording medium is desired that has a large capacity for recording a large amount of information, is inexpensive, and can read out a necessary portion preferably in a short time and can perform so-called high-speed access. As an example of this, a high-density magnetic recording medium made of a flexible disk such as a hard disk or ZIP (Iomega Corporation) is known. These high-density magnetic recording media have an information recording area composed of narrow tracks. In order to reproduce a signal with a high S / N by accurately scanning a narrow track width with a magnetic head, a so-called tracking servo technique is used. It plays a big role.
[0003]
Servo information such as a track positioning servo signal, a track address signal, and a reproduction clock signal must be recorded in advance on the magnetic recording medium as a preformat when the magnetic recording medium is manufactured. As a method for accurately and efficiently performing this preformatting, for example, Patent Documents 1 and 2 propose a method of transferring a pattern carrying servo information formed on a master carrier to a magnetic recording medium by magnetic transfer. .
[0004]
Magnetic transfer corresponds to the transfer pattern of the master carrier by applying a magnetic field for transfer with the master carrier carrying the information to be transferred in close contact with a magnetic recording medium (slave medium) such as a magnetic disk medium. The magnetic pattern to be transferred is magnetically transferred to the slave medium, and can be recorded statically without changing the relative position of the master carrier and the slave medium, enabling accurate preformat recording. Moreover, there is an advantage that the time required for recording is extremely short.
[0005]
The master carrier includes a substrate on which a concavo-convex pattern corresponding to transfer information is formed and a magnetic layer provided on at least the convex portion of the substrate, or a substrate on which the concavo-convex pattern is formed and a concave portion of the substrate. A material composed of a magnetic layer embedded in the substrate has been proposed.
[0006]
Since the master carrier is very expensive, development of a highly durable master carrier capable of performing magnetic transfer to more slave media is required, and as a method for improving the durability of the master carrier, Patent Documents 3 and 4 propose a method of providing a DLC film (diamond-like carbon film) on the surface of the magnetic layer of the master carrier, or a method of providing a lubricant layer on the uppermost layer as a contact surface with the slave medium. Yes. Further, in Patent Document 5, in a Si substrate having a concavo-convex pattern and a master carrier in which a magnetic layer is embedded in a concave portion thereof so as to be flush with the surface of the Si substrate, the substrate and the magnetic layer are flush with each other. In the case of providing a protective layer, a method of providing a metal thin film under the protective layer has been proposed as a method for improving the durability by preventing peeling of the protective layer.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-40544
[Patent Document 2]
Japanese Patent Laid-Open No. 10-269566
[Patent Document 3]
Japanese Patent Laid-Open No. 2000-195048
[Patent Document 4]
Japanese Patent Laid-Open No. 2001-14665
[Patent Document 5]
Japanese Patent Laid-Open No. 2001-176067
[Problems to be solved by the invention]
The magnetic transfer process includes a process of adhering the master carrier and the slave medium uniformly over the entire surface with a relatively strong pressure, and a process of peeling both after applying a magnetic field. It is necessary to repeat this adhesion and peeling process with respect to the master carrier. On the other hand, while repeating this adhesion and peeling, the magnetic layer on the substrate of the master carrier peels from the substrate, the transfer failure occurs due to the magnetic layer peeling part and the peeled magnetic layer being interposed in the adhesion part, The problem that the surface of the master carrier and the slave medium is damaged by the peeled magnetic layer has been revealed. Therefore, it is desired to improve the durability of the master carrier by reducing the peeling of the magnetic layer from the substrate in many adhesion and peeling processes.
[0013]
However, as described in Patent Documents 3 and 4, when a protective layer or a lubricant layer is provided on the magnetic layer, an effect of preventing damage to the surface of the master carrier due to dust or the like can be obtained. Since the effect of improving the adhesion with the substrate cannot be obtained, it is impossible to suppress the peeling of the magnetic layer from the substrate due to repeated adhesion and peeling with the slave medium. Moreover, the master carrier described in Patent Document 5 is for improving the adhesion between the Si substrate and the protective layer, and suppressing the peeling of the magnetic layer embedded in the concave portion of the substrate However, a master carrier having a non-embedded magnetic layer cannot obtain the effect of suppressing the peeling of the magnetic layer from the substrate.
[0014]
In view of the above circumstances, an object of the present invention is to provide a magnetic transfer master carrier with improved durability and suppressed transfer failure, and a magnetic transfer method using the master carrier.
[0015]
[Means for Solving the Problems]
The magnetic transfer master carrier of the present invention is a magnetic transfer master carrier having a concavo-convex pattern formed on the surface according to desired information,
A ferromagnetic substrate;
A quasi-intermediate layer made of at least one of oxide, nitride and carbide formed on the surface of the substrate;
An intermediate layer made of at least one of Si, B, Al, Ti, Cr, V, Ni, Cu, Fe, Co, Gd, Sm and Nd formed on the quasi-intermediate layer;
And a magnetic layer formed on the intermediate layer.
[0016]
The intermediate layer may be a single layer or a plurality of layers, but it is desirable that the total thickness is 5 to 100 nm (including 5 nm and 100 nm, the same applies hereinafter).
[0017]
The quasi-intermediate layer may be configured by subjecting the surface of the substrate to at least one of oxidation, nitridation, and carbonization treatment, or at least one of an oxide layer, a nitride layer, and a carbide layer. May be newly laminated on the substrate.
[0018]
The quasi-intermediate layer has a thickness of 0.1 to 20 nm, a ratio of the total amount of oxygen, nitrogen and / or carbon to the total element amount of the quasi-intermediate layer is 0.5 to 30 at%, and It is desirable to have magnetism.
[0019]
The ferromagnetic substrate is preferably made of Ni or an alloy containing Ni as a main component.
[0020]
The desired information includes, for example, a servo signal, but may include other various data.
[0021]
In the magnetic transfer method of the present invention, the surface of the magnetic transfer master carrier of any one of the present invention and the magnetic layer of the recording medium having a magnetic layer are brought into close contact with the recording medium and the master carrier. The information is transferred to the recording medium by applying a magnetic field.
[0022]
【The invention's effect】
According to the magnetic transfer master carrier of the present invention, between the substrate and the magnetic layer, a quasi-intermediate layer made of at least one of oxide, nitride and carbide, and Si, B, Al, Ti, Cr, By providing an intermediate layer composed of at least one of V, Ni, Cu, Fe, Co, Gd, Sm, and Nd, the entire surface of the master carrier and the slave medium is adhered and peeled off for magnetic transfer. When the is repeated, peeling of the magnetic layer can be suppressed and durability can be improved. Since peeling of the magnetic layer can be suppressed, transfer defects caused by peeling of the magnetic layer and damage to the surface of the recording medium that is a master carrier or slave medium can also be suppressed.
[0023]
In the magnetic transfer master carrier of the present invention, the substrate is made of a ferromagnetic material, and not only the magnetic layer on the substrate but also the magnetism of the substrate contributes to signal recording during magnetic transfer. Therefore, the quasi-intermediate layer and the intermediate layer provided between the substrate and the magnetic layer need to suppress the peeling of the magnetic layer to improve durability and maintain the magnetic coupling between the substrate and the magnetic layer. There is. By making the thickness of the quasi-intermediate layer 5 to 100 nm and the thickness of the intermediate layer about 0.1 to 20 nm, the durability is improved, and even if both layers are non-magnetic, it is between the substrate and the magnetic layer. High quality transfer can be performed without breaking the magnetic coupling.
[0024]
In addition, if the quasi-intermediate layer and / or the intermediate layer has magnetism, the magnetic coupling between the substrate and the magnetic layer is not reduced, so that particularly high quality transfer is possible.
[0025]
If the total amount of oxygen, nitrogen and / or carbon in the quasi-intermediate layer is in the range of 0.5 to 30 at% with respect to the total element amount of the intermediate layer, the magnetic coupling force between the substrate and the magnetic layer It is possible to improve the adhesion without adversely affecting the adhesion.
[0026]
Since the magnetic transfer method of the present invention uses the magnetic transfer master carrier of the present invention described above, transfer failure due to peeling of the magnetic layer and the like can be suppressed, and a single master carrier is used. Since transfer to a large number of recording media can be performed, a recording medium with good transfer quality can be manufactured at low cost.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0028]
FIG. 1 is a partial perspective view of the surface of the magnetic transfer master carrier of the present embodiment, and FIG. 2 is a partial cross-sectional view of the master carrier of FIG.
[0029]
The master carrier 3 of this embodiment is formed in a disk shape as shown in FIG. 3 to be described later, and has a concavo-convex pattern corresponding to information to be transferred to a magnetic recording medium as a slave medium on its surface as a transfer pattern. Is. The information to be transferred includes, for example, a servo signal, but may include other various data. A partial pattern of the concavo-convex pattern is, for example, as shown in FIG. In FIG. 1, an arrow X indicates a circumferential direction (track direction), and an arrow Y indicates a radial direction.
[0030]
FIG. 2 is a cross-sectional view taken along the line II-II of the master carrier 3 shown in FIG.
[0031]
The master carrier 3 includes a substrate 31 having an uneven pattern on the surface, a quasi-intermediate layer 32 formed on the substrate 31, an intermediate layer 33 formed on the quasi-intermediate layer 32, and the intermediate layer 33. The magnetic layer 34 is formed.
[0032]
The substrate 31 is ferromagnetic and is particularly preferably made of Ni or an alloy containing Ni as a main component. The substrate 31 having a concavo-convex pattern on the surface can be produced using a stamper method, a photolithography method, or the like.
[0033]
An outline of a method for manufacturing the substrate 31 will be described. First, a photoresist is formed on a glass plate (or quartz plate) with a smooth surface by spin coating or the like, and laser light (or electron beam) modulated in response to a servo signal is irradiated while rotating the glass plate. Then, a predetermined pattern on the entire surface of the photoresist, for example, a pattern corresponding to a servo signal extending linearly in the radial direction from the center of rotation to each track is exposed to a portion corresponding to each frame on the circumference, and then the photoresist is applied. Development is performed to remove the exposed portion, and a master having a concavo-convex shape by a photoresist is obtained. Next, based on the concavo-convex pattern on the surface of the master, the surface is plated (electroformed) to produce a Ni substrate having a positive concavo-convex pattern and peeled off from the master.
[0034]
Alternatively, the master may be plated to produce a second master, and the second master may be used for plating to produce a substrate having a negative uneven pattern. Furthermore, plating may be performed on the second master or a resin solution may be pressed and cured to produce a third master, and the third master may be plated to produce a substrate having a positive uneven pattern. .
[0035]
As the plating, various metal film forming methods including electroless plating, 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 this uneven 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 length in the radial direction is preferably 0.05 to 20 μm, and the circumferential direction is preferably 0.05 to 5 μm. The value of the servo signal is to select a value that has a longer shape in the radial direction within this range. It is preferable as a pattern for supporting.
[0036]
The quasi-intermediate layer 32 is made of an oxide, nitride, and / or carbide, and the ratio of the total amount of oxygen, nitrogen and / or carbon in the quasi-intermediate layer 32 to the total element amount of the quasi-intermediate layer 32 is , Preferably in the range of 0.5 to 30 at%. Furthermore, it is desirable that the quasi-intermediate layer 32 is magnetic and has a thickness in the range of 0.1 to 20 nm.
[0037]
Examples of the method for producing the quasi-intermediate layer 32 include a method in which the surface layer of the substrate 31 is changed to the quasi-intermediate layer 32 by oxidizing the surface of the substrate 31. For example, the surface layer is oxidized by subjecting the surface of the substrate 31 to an ashing process using oxygen plasma, and this surface layer portion is used as a quasi-intermediate layer containing oxygen.
[0038]
The quasi-intermediate layer 32 can also be formed on the substrate by sputtering or the like. For example, a magnetic layer having an oxidized, nitrided, and / or carbonized portion can be formed as the quasi-intermediate layer 32 by introducing a reactive gas during the film formation of the magnetic material. More specifically, a magnetic layer having an oxidized portion can be formed by performing reactive sputtering using Ar added with an oxidizing gas (for example, oxygen) during sputtering film formation. For nitriding, nitrogen is added to Ar, and for carbonization, Ar added with a hydrocarbon such as methane may be used.
[0039]
The intermediate layer 33 is made of a material composed of one element or a combination of two or more elements among Si, B, Al, Ti, Cr, V, Ni, Cu, Fe, Co, Gd, Sm, and Nd. It is a thing. It should be noted that metals such as Si, B, Al... Are particularly easily compounded with Ni, and the effect of strengthening the adhesion is particularly high when the substrate 31 is Ni or a Ni alloy. The intermediate layer may be a single layer or a multilayer of two or more layers, but the total thickness is in the range of 5 to 100 nm. The intermediate layer 33 is more preferably made of a ferromagnetic metal such as Ni, Fe, or Co so as not to weaken the magnetic coupling between the substrate 31 and the magnetic layer 34.
[0040]
As the magnetic material of the magnetic layer 34, Co, Co alloy (CoNi, CoNiZr, CoNbTaZr, etc.), Fe, Fe alloy (FeCo, FeCoNi, FeNiMo, FeAlSi, FeAl, FeTaN), Ni, Ni alloy (NiFe) should be used. Particularly preferred are FeCo and FeCoNi. As the magnetic layer 34, by using a magnetic layer having a small coercive force such as soft magnetism or semi-hard magnetism, better transfer can be performed. Further, the magnetic layer 34 preferably has a saturation magnetization value higher than that of the substrate 31. The thickness of the magnetic layer (the thickness of the magnetic layer on the upper surface of the convex portion) is preferably in the range of 50 to 500 nm, more preferably 80 to 300 nm.
[0041]
The intermediate layer 33 and the magnetic layer 34 can be formed on the substrate 31 by using, for example, a vacuum deposition method such as a vacuum deposition method, a sputtering method, or an ion plating method, a plating method, or the like using a magnetic material.
[0042]
As described above, the master carrier 3 is provided with the quasi-intermediate layer 32 and the intermediate layer 33 between the substrate 31 and the magnetic layer 34, thereby improving the adhesion between the substrate 31 and the magnetic layer 34. The peeling of the magnetic layer 34 can be suppressed, and the durability of the master carrier can be improved. By improving the durability of the master carrier, magnetic transfer to a larger number of slave media becomes possible, and an overall cost reduction effect can be obtained.
[0043]
A protective film such as diamond-like carbon (DLC) of 5 to 30 nm is preferably provided on the magnetic layer 34, and a lubricant layer may be further provided. Further, an adhesion reinforcing layer such as Si may be provided between the magnetic layer and the protective film. By providing the lubricant, it is possible to suppress the occurrence of scratches due to friction when correcting the deviation generated in the contact process with the slave medium, and to further improve the durability.
[0044]
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.
[0045]
FIG. 3 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. Further, in the present embodiment, the recording surface 2b, 2c provided with the in-plane magnetic recording layer 22 on both surfaces of the disc-shaped substrate 21 is shown.
[0046]
The master carrier 3 is the same as that shown in the above embodiment, and a concavo-convex pattern corresponding to the servo signal is formed in the servo area 35 as the concavo-convex pattern for the lower recording surface 2b of the slave medium 2. Further, the master carrier 4 is formed with an uneven pattern for the upper recording surface 2 c of the slave medium 2 having the same layer structure as the master carrier 3.
[0047]
Although FIG. 3 shows a state where the magnetic recording medium 2 and the master carriers 3 and 4 are separated from each other, the actual magnetic transfer is performed by using the transfer patterns of the recording surfaces 2 b and 2 c of the magnetic recording medium 2 and the master carriers 3 and 4. This is done with the surface in close contact.
[0048]
FIG. 4 is a perspective view showing a schematic configuration of a magnetic transfer apparatus for performing magnetic transfer using the magnetic transfer master carrier of the present invention. The magnetic transfer apparatus 1 obtains an adhesive force by vacuum-sucking the air in the internal space of the transfer holder 10 that holds the master carrier 3 and 4 and the slave medium 2 in close contact with each other and the internal space of the transfer holder 10 to obtain an adhesive force (not shown) A contact pressure applying means including a vacuum suction means and a magnetic field applying means 55 for applying a transfer magnetic field while rotating the transfer holder 10 are provided.
[0049]
The magnetic field applying means 55 includes electromagnet devices 50, 50 disposed on both sides of the transfer holder 10, and a coil 53 is wound around a core 52 having a gap 51 extending in the radial direction of the transfer holder 10 of the electromagnet device 50. It will be. Both electromagnet devices 50, 50 generate magnetic fields in the same direction parallel to the track direction. Further, the magnetic field applying means 55 may be constituted by a permanent magnet device instead of the electromagnet device. The magnetic field applying means in the case of perpendicular recording can be composed of electromagnets or permanent magnets having different polarities disposed on both sides of the transfer holder 10. That is, in the case of perpendicular recording, a transfer magnetic field is generated in a direction perpendicular to the track surface.
[0050]
Further, the magnetic field applying unit 55 is configured so that the electromagnet devices 50 and 50 on both sides move toward and away from each other or the transfer holder 10 is inserted between the electromagnet devices 50 and 50 so as to allow the opening and closing operation of the transfer holder 10. The electromagnet devices 50 and 50 or the holder 10 are adapted to move.
[0051]
The transfer holder 10 includes a left-side holder 11 and a right-side other holder 12 that can be moved toward and away from each other, and the slave medium 2 and the master carrier 3 are accommodated in an internal space formed therein. The slave medium 2 and the master carrier 3 are overlapped and brought into close contact with each other in a state where the center positions are matched by the decompression of the internal space.
[0052]
One master carrier 3 and slave medium 2 for transferring information such as servo signals to one side of the slave medium 2 are held by suction or the like on the pressing surface of the one side holder 11, and The other master carrier 4 for transferring information such as servo signals to the other surface of the medium 2 is held by suction or the like.
[0053]
Support shafts project from the center positions of the back surfaces of the one-side holder 11 and the other-side holder 12, are supported by the apparatus main body, are linked to a rotation mechanism, and are rotated during magnetic transfer.
[0054]
In addition, the internal space of the transfer holder 10 is depressurized to a predetermined degree of vacuum at the time of close contact to obtain close contact between the slave medium 2 and the master carriers 3 and 4, and the close contact surface is vented to improve the close contact. In addition to increasing the pressure, compressed air is introduced when the atmosphere is released and when it is peeled off. In addition to applying vacuum suction, the transfer holder may be mechanically pressurized from the outside in order to apply adhesion.
[0055]
Next, a magnetic transfer method using the magnetic transfer apparatus 1 will be described. The transfer holder 10 of the magnetic transfer apparatus performs magnetic transfer to a plurality of slave media 2 by a set of master carriers 3 and 4. First, the master carriers 3 and 4 are respectively attached to the one-side holder 11 and the other-side holder 12. Keep the position aligned. Then, in a state where the one-side holder 11 and the other-side holder 12 are separated from each other, the slave medium 2 that has been initially magnetized in advance in one of the in-plane direction and the vertical direction is set with the center position aligned, and then the other-side holder 12 is placed on one side. The holder 11 is moved close to the closed state. The internal space of the transfer holder 10 containing the slave medium 2 and the master carriers 3 and 4 is depressurized by vacuum suction, and the slave medium 2 and the master carriers 3 and 4 are evenly adhered to each other by applying an even adhesion force. In order to apply the adhesion, in addition to vacuum suction, the transfer holder may be mechanically pressurized from the outside.
[0056]
Thereafter, the electromagnet device 50 is brought close to both sides of the transfer holder 10, and a magnetic field for transfer is applied in a direction almost opposite to the initial magnetization by the electromagnet device 50 while rotating the transfer holder 10, and magnetization according to the transfer pattern of the master carrier 3. The pattern is transferred and recorded on the magnetic recording layer of the slave medium 2.
[0057]
FIG. 5 is a diagram for explaining a basic process of magnetic transfer to the in-plane magnetic recording medium. FIG. 5A is a process of applying a magnetic field in one direction to initially DC magnetize the slave medium. ) Is a process of applying a magnetic field in a direction substantially opposite to the initial DC magnetic field by bringing the master carrier and the slave medium into close contact with each other, and FIG. In FIG. 5, only the lower recording surface 2b side of the slave medium 2 is shown.
[0058]
As shown in FIG. 5A, an initial direct current magnetic field Hin in one direction of the track is applied to the slave medium 2 in advance to cause the magnetic recording layer 22 to undergo initial direct current magnetization. Thereafter, as shown in FIG. 5 (b), the recording surface 2b of the slave medium 2 and the transfer pattern surface of the master carrier 3 are brought into close contact with each other, and in the track direction of the slave medium 2, the direction of the initial DC magnetic field Hin is opposite. A transfer magnetic field Hdu is applied. At the place where the transfer pattern of the slave medium 2 and the master carrier 3 is in close contact, the transfer magnetic field Hdu is sucked into the convex portion of the master carrier 3, and the magnetization of the slave medium 2 corresponding to this portion is not reversed and other portions The initial magnetization is reversed. As a result, as shown in FIG. 5C, information (for example, servo signals) corresponding to the uneven pattern of the master carrier 3 is magnetically transferred and recorded on the magnetic recording layer 22 of the lower recording surface 2b of the slave medium 2. Is done. Here, the magnetic transfer by the lower master carrier 3 to the lower recording surface 2b of the slave medium 2 has been described, but the upper recording surface 2c of the magnetic recording medium 2 is also brought into close contact with the upper master carrier 4 in the same manner. I do. Note that the magnetic transfer to the upper and lower recording surfaces 2b and 2c of the magnetic recording medium 2 may be performed simultaneously or sequentially one by one.
[0059]
Note that the initial DC magnetic field and the transfer magnetic field need to adopt values determined in consideration of the coercivity of the slave medium, the relative permeability of the master carrier and the slave medium, and the like.
[0060]
The basic process of magnetic transfer shown in FIG. 5 is for the case where the slave medium is an in-plane recording medium. However, when the slave medium is a perpendicular recording medium, the initial magnetization direction and the application of the transfer magnetic field are applied. The direction may be a direction perpendicular to the surface. In the case of perpendicular recording, the initial magnetization of the portion in close contact with the convex portion of the master carrier is reversed and the initial magnetization of the other portion is not reversed. As a result, the magnetization pattern corresponding to the concavo-convex pattern is transferred.
[0061]
As the slave medium 2, a disk-shaped magnetic recording medium having a coating type magnetic recording layer or a metal thin film type magnetic recording layer, such as a hard disk or a high-density flexible disk, can be used.
[0062]
In the case of a magnetic recording medium having a metal thin film type magnetic recording layer, Co, Co alloy (CoPtCr, CoCr, CoPtCrTa, CoPtCrNbTa, CoCrB, CoNi, Co / Pd, etc.), Fe, Fe alloy (FeCo) FePt, FeCoNi) can be used. The magnetic layer preferably has a high magnetic flux density, and has magnetic anisotropy in the in-plane direction for in-plane recording and in the vertical direction for perpendicular recording, because clear transfer can be achieved. The preferred magnetic layer thickness is 10 to 500 nm, more preferably 20 to 200 nm.
[0063]
In addition, a nonmagnetic underlayer is preferably provided under the magnetic layer (on the substrate side) in order to give the magnetic layer the necessary magnetic anisotropy. As the underlayer, Cr, CrTi, CoCr, CrTa, CrMo, NiAl, Ru, Pd, etc. can be used, but the crystal structure and lattice constant coincide with the crystal structure and lattice constant of the magnetic layer provided thereon. You need to choose what you want. The thickness of the preferable nonmagnetic layer is 10 to 150 nm, more preferably 20 to 80 nm.
[0064]
Further, in the case of a perpendicular magnetic recording medium, a soft magnetic backing layer may be provided under the nonmagnetic underlayer in order to stabilize the perpendicular magnetization state of the magnetic layer and improve the sensitivity during recording and reproduction. . As this backing layer, NiFe, CoCr, FeTaC, FeAlSi, or the like can be used. The thickness of the preferable backing layer is 50 to 2000 nm, more preferably 60 to 400 nm.
[0065]
Next, a partial sectional view of the magnetic transfer master carrier according to the second embodiment of the present invention will be described with reference to FIG.
[0066]
As shown in FIG. 4, the magnetic transfer master carrier 3 ′ of the second embodiment is formed on the flat substrate 41, the quasi-intermediate layer 42 formed on the substrate 41, and the quasi-intermediate layer 42. It consists of an intermediate layer 43 and a magnetic layer 44 formed on the intermediate layer 43 and having an uneven pattern on the surface. The materials constituting the substrate 41, the quasi-intermediate layer 42, the intermediate layer 43, and the magnetic layer 44, the thickness of the quasi-intermediate layer 42, the ratio of oxygen, nitrogen and / or carbon, and the thickness of the intermediate layer 43 are all the above-described first. It is the same as that of the master carrier of the embodiment.
[0067]
Thus, even in a master carrier having a magnetic layer having a concavo-convex pattern with respect to a flat substrate, peeling of the magnetic layer is suppressed by providing a quasi-intermediate layer and an intermediate layer between the substrate and the magnetic layer And the durability can be improved.
[0068]
The magnetic transfer method using the magnetic transfer master carrier of the second embodiment is the same as that of the magnetic transfer master carrier of the first embodiment, and a detailed description thereof will be omitted.
[0069]
【Example】
Next, the results of manufacturing and evaluating the magnetic transfer master carrier of the examples and comparative examples of the present invention will be described.
[0070]
First, each master carrier will be described.
[0071]
The master carrier of the magnetic transfer apparatus of Example 1 was provided with a disk-shaped Ni substrate manufactured using a stamper manufacturing method as a substrate. The Ni substrate has a track width of 0.3 μm, a track pitch of 0.32 μm, a bit length of 0.15 μm at the position of 20 mm in the radial direction, which is the innermost circumference, and a convex part height within a range of 20-40 mm in the radial direction from the center of the disk A concave / convex pattern signal having a concave groove depth of 0.1 μm was formed.
[0072]
Ashing treatment with oxygen plasma was performed on the substrate surface, and a quasi-intermediate layer was formed on the surface layer of the substrate. At this time, the oxygen concentration in the quasi-intermediate layer was 3 at%. On the quasi-intermediate layer, Cu 5 nm was laminated as an intermediate layer, and FeCo 30 at%, 100 nm was laminated as a magnetic layer on the intermediate layer. Both the intermediate layer and the magnetic layer were sequentially formed in a vacuum deposition apparatus (Shibaura Metronics: Octava sputtering apparatus) at a substrate temperature of 25 ° C. In the formation of the magnetic layer, the Ar sputtering pressure was 1.5 × 10 ⁻¹ Pa (1.08 mTorr) in a state where the atmosphere was reduced to 1.33 × 10 ⁻⁵ Pa (10 ⁻⁷ Torr), and the input power was 2.80 W. / Cm ² .
[0073]
The thickness of the quasi-intermediate layer and the oxygen concentration were defined as follows.
[0074]
A standard sample is prepared using oxygen concentration, input power, etc., as parameters when oxygen ashing is performed on the substrate surface, and the oxygen concentration of the sample and the substrate are subjected to Ar etching in the depth direction from the surface of the substrate. The Ni concentration as the material was measured with an Auger spectrometer. By this measurement, for example, as shown in FIG. 7, the oxygen concentration in the substrate depth direction from the substrate surface (FIG. 7A) and the Ni concentration distribution (FIG. 7B) based on the substrate surface before ashing. ) In the concentration distribution diagram shown in FIG. 7, the depth do, which is an intermediate concentration value Omid (= (Omax + Omin) / 2) between the maximum oxygen concentration value Omax and the minimum oxygen concentration value Omin, the maximum Ni concentration value Nmax, and the minimum Ni concentration value. A depth dn at which an intermediate concentration value Nmid (= (Nmax + Nmin) / 2) of Nmin is determined, and an intermediate point d between the depth do and the depth dn is defined as the thickness of the quasi-intermediate layer. Moreover, the average value of the oxygen concentration in the thickness range of the quasi-intermediate layer was defined as the oxygen concentration of the quasi-intermediate layer.
[0075]
A plurality of standard samples with different oxygen concentrations, input power, etc. at the time of ashing are prepared in advance, and the quasi-intermediate layer thickness and oxygen concentration are obtained by the above-described procedure, respectively. Interlayer thickness and oxygen concentration were considered.
[0076]
As a slave medium, a 3.5-inch disk-shaped magnetic recording medium having a magnetic layer with a saturation magnetization Ms: 5.7 T (4500 Gauss) and a coercive force Hc: 199 kA / m (2500 Oe) on an Al substrate is used. It was.
[0077]
Example 2 was the same master carrier for magnetic transfer as Example 1, except that B was used as the intermediate layer and that the oxygen concentration of the intermediate layer was 4 at%.
[0078]
Example 3 was the same master carrier for magnetic transfer as Example 1 except that Si was used as the intermediate layer and that the oxygen concentration of the intermediate layer was 2 at%.
[0079]
Example 4 was the same master carrier for magnetic transfer as Example 3 except that the thickness of the intermediate layer was 2 nm and the thickness of the quasi-intermediate layer was 6 nm.
[0080]
Example 5 was the same master carrier for magnetic transfer as Example 3 except that the thickness of the intermediate layer was 120 nm and the thickness of the quasi-intermediate layer was 7 nm.
[0081]
Example 6 was the same master carrier for magnetic transfer as Example 3 except that the thickness of the quasi-intermediate layer was 0.05 nm.
[0082]
Example 7 was the same master carrier for magnetic transfer as Example 3 except that the thickness of the quasi-intermediate layer was 25 nm.
[0083]
Example 8 was the same master carrier for magnetic transfer as Example 3 except that the oxygen concentration of the quasi-intermediate layer was 0.2 at%.
[0084]
Example 9 was the same master carrier for magnetic transfer as Example 3 except that the oxygen concentration of the quasi-intermediate layer was 34 at%.
[0085]
Example 10 was the same master carrier for magnetic transfer as Example 3 except that Fe was used as the intermediate layer.
[0086]
Comparative Example 1 was a master carrier for magnetic transfer similar to Example 1 except that the Ni substrate surface was not oxidized, that is, the quasi-intermediate layer was not provided.
[0087]
Comparative Example 2 was the same magnetic transfer master carrier as Example 1 except that Au was used as the intermediate layer.
[0088]
For the magnetic transfer master carriers of Examples 1 to 10 and Comparative Examples 1 and 2, magnetic transfer was performed on 10,000 slave media, and the following measurements and evaluations were performed. The contact pressure between the master carrier and the slave medium during magnetic transfer was 0.49 MPa (5.0 kgf / cm ² ).
[0089]
<Measurement and evaluation method of defective transfer location>
Measurements were made on the location of transfer failure due to pattern breakage of the master carrier.
[0090]
The first, 10, 100, 1000, and 10,000th slave media and the defect portion over the entire surface of the master carrier at each contact number were detected at a magnification of 3 times using a telecentric device. For the slave medium, a transfer defect portion was further detected from the reproduction signal of the transferred magnetization pattern. That is, in the slave medium, both the geometric defect and the defect due to transfer failure are regarded as the defects in the slave medium.
[0091]
The defect part on the master carrier and the defect part on the slave medium were compared, and the coincidence was regarded as a defect due to pattern breakage of the master carrier. When the number of defects due to this pattern breakage was less than 5, it was evaluated as good (◯), 5-9 were acceptable (Δ), and 10 or more were evaluated as defective (x). In addition, it was evaluated as defective if there were at least 10 defective portions even once up to the 10,000th sheet.
[0092]
<Signal quality evaluation method>
The transfer signal of the slave medium was evaluated using an electromagnetic conversion characteristic measuring device (SS-60 manufactured by Kyodo Electronics). As the head, a GMR head having a reproducing head gap of 0.12 μm, a reproducing track width of 0.6 μm, a recording head gap of 0.18 μm, and a recording track width of 0.75 μm was used. For the first and 10000th slave media, the read signal is frequency-resolved with a spectroanalyzer, and the difference (C / N) between the peak intensity (C) of the primary signal and the medium noise (N) obtained by extrapolation is obtained. It was measured. The C / N value of the first sheet was set to 0 dB, and the relative value ΔC / N of the first sheet and the 10,000th sheet was obtained and evaluated. When ΔC / N was less than −2.0 dB, it was evaluated as good (◯), when it was −2.0 to −3.0 dB, it was acceptable (Δ), and when it was larger than −3.0 dB, it was evaluated as defective (×).
[0093]
The measurement and evaluation results are shown in Table 1.
[0094]
[Table 1]

As shown in Table 1, for Examples 1 to 10, which are examples of the present invention, the above results were obtained for both the number of defects and signal quality due to pattern breakage, while for Comparative Examples 1 and 2 Was evaluated as defective in terms of at least one of the number of defects and signal quality due to pattern breakage.
[Brief description of the drawings]
1 is a partial perspective view of the surface of a magnetic transfer master carrier. FIG. 2 is a sectional view of the magnetic transfer master carrier of FIG. 1. FIG. 3 is a perspective view of a master carrier and a slave medium. FIG. 5 is a perspective view showing a schematic configuration of a transfer apparatus. FIG. 5 is a diagram showing basic steps of a magnetic transfer method to an in-plane magnetic recording medium. FIG. FIG. 7 is a partial cross-sectional view. FIG. 7 is a diagram for explaining how to determine the thickness of the quasi-intermediate layer in the embodiment.
DESCRIPTION OF SYMBOLS 1 Magnetic transfer apparatus 2 Slave media 2b, 2c Recording surface 3, 4 Master carrier 10 Transfer holder 21 Substrate medium substrate 22 Slave medium magnetic recording layer (magnetic layer)
31 Substrate 32 Quasi-intermediate layer 33 Intermediate layer 34 Magnetic layer 50 Electromagnet device 55 Magnetic field applying means

Claims (6)

A master carrier for magnetic transfer having a concavo-convex pattern formed on the surface according to desired information,
A ferromagnetic substrate;
A quasi-intermediate layer made of at least one of oxide, nitride and carbide formed on the surface of the substrate;
An intermediate layer made of at least one of Si, B, Al, Ti, Cr, V, Ni, Cu, Fe, Co, Gd, Sm and Nd formed on the quasi-intermediate layer;
A magnetic transfer master carrier comprising: a magnetic layer formed on the intermediate layer. 2. The magnetic transfer master carrier according to claim 1, wherein the intermediate layer has a thickness of 5 to 100 nm. 3. The magnetic transfer master carrier according to claim 1, wherein the quasi-intermediate layer has a thickness of 0.1 to 20 nm. The ratio of the total amount of oxygen, nitrogen and / or carbon in the quasi-intermediate layer to the total element amount in the quasi-intermediate layer is 0.5 to 30 at%. The master carrier for magnetic transfer as described. The magnetic transfer master carrier according to claim 1, wherein the quasi-intermediate layer is magnetic. A magnetic field is applied to the recording medium and the master carrier in a state where the surface of the magnetic transfer master carrier according to any one of claims 1 to 5 and the magnetic layer of the recording medium having a magnetic layer are in close contact with each other. And transferring the information onto the recording medium.

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