JP2004079098A - Recording medium, method for manufacturing recording medium, imprint original plate and method for manufacturing imprint original plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a patterned recording medium that can be manufactured by a simple and inexpensive method and that information can be stably written/read. <P>SOLUTION: This recording medium comprises a medium substrate (11), a buffer layer (12) formed on the medium substrate (11) and a recording layer (14) including recording material grains (13) formed on the buffer layer (12). The recording material grains (13) are formed into hexagonal lattices and arranged forming the surface of the recording layer (14) in practically parallel with the surface of the medium substrate (11). A part where two or more layers of the recording material grains (13) are layered from the surface toward the depth direction of the buffer layer (12) is provided. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a recording medium having a patterned recording layer, a method for manufacturing the same, an imprint master having a patterned metal layer, a method for manufacturing the same, and a recording layer patterned using the imprint master. The present invention relates to a method for manufacturing a recording medium having the same.
[0002]
[Prior art]
2. Description of the Related Art Due to the dramatic improvement in functions of information devices such as personal computers, the amount of information handled by users has been significantly increased. Under such circumstances, expectations for magnetic recording media and optical recording media having significantly higher recording densities than ever, and for semiconductor devices having a high degree of integration are only increasing.
[0003]
For example, in order to improve the recording density of a magnetic recording medium, it is desirable to form so-called patterned media in which magnetic fine particles included in a magnetic recording layer are finely divided and magnetically separated from each other. In order to form a magnetic recording layer containing such fine magnetic particles separated from each other, finer processing techniques are required.
[0004]
That is, the conventional photolithography technology using an exposure process can perform fine processing of a large area at once, but does not have a resolution equal to or less than the wavelength of light, so that it is difficult to manufacture a fine structure of about 100 nm or less. . On the other hand, as a processing technique at a level of 100 nm or less, techniques such as electron beam lithography and focused ion beam lithography exist, but the problem of poor throughput is a problem. Therefore, there is a demand for a method that can more easily manufacture a patterned medium having a fine pattern.
[0005]
Also, as a method for producing a fine structure having a wavelength equal to or less than the wavelength of light at high throughput, S.S. Y. Chou et al., Appl. Phys. Lett. , Vol. 76 (1995) p. There is “Nanoimprint Lithography (NIL) technology” proposed in 3114. Nanoimprint lithography technology is to prepare an imprint master having a predetermined fine uneven pattern in advance by electron beam lithography and the like, press the imprint master against the substrate to which the resist has been applied, and remove the unevenness of the master on the target substrate. This is a method of transferring to a resist film. The time required for one processing in this method can be very short in a region of, for example, 1 square inch or more, as compared with electron beam lithography or focused ion beam lithography.
[0006]
Conventionally, a nanoimprint master has been manufactured using photolithography, electron beam lithography, or focused ion beam lithography. However, when producing a nanoimprint master, the same problem as in the production of patterned media described above occurs, and it is difficult to obtain a resolution of 100 nm or less by optical lithography. Is a problem. For this reason, there is a demand for a method that can more easily manufacture an imprint master having a fine pattern.
[0007]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a patterned recording medium that can be manufactured by a simple and inexpensive method and that can write and read information stably, and a method that can easily and inexpensively manufacture such a recording medium. Is to provide.
[0008]
Another object of the present invention is an imprint master that can be manufactured by a simple and inexpensive method, a method that can easily and inexpensively manufacture such an imprint master, and a pattern formed by using the imprint master. An object of the present invention is to provide a method for manufacturing a recording medium.
[0009]
[Means for Solving the Problems]
A recording medium according to one embodiment of the present invention includes a medium substrate, a buffer layer formed on the medium substrate, and a recording layer containing recording material fine particles formed on the buffer layer, wherein the recording material The fine particles are arranged in a hexagonal lattice to form a surface of the recording layer substantially parallel to the medium substrate surface, and two or more layers of the recording material fine particles extend from the surface in the depth direction of the buffer layer. It is characterized by having a laminated portion.
[0010]
The method for manufacturing a recording medium according to one embodiment of the present invention includes a step of forming a resist layer on a replica substrate, spraying recording material fine particles on the resist layer, and stacking two or more layers of recording material fine particles. Forming a recording layer, applying a buffer material on the recording layer, curing the buffer material in a state where a medium substrate is pressed on the buffer material to form a buffer layer, the replica substrate and the resist layer, The method is characterized in that the medium substrate, the buffer layer and the recording layer are separated.
[0011]
An imprint master according to another aspect of the present invention includes an imprint substrate, a buffer layer formed on the imprint substrate, and a fine particle layer formed on the buffer layer, wherein the fine particle layer is The fine particles are arranged in a hexagonal lattice to form a surface substantially parallel to the imprint surface, and have a portion where two or more layers of fine particles are stacked from the surface in the depth direction of the buffer layer. It is characterized by.
[0012]
The method of manufacturing an imprint master according to another aspect of the present invention includes forming a resist layer on a replica substrate, forming a fine particle layer having a portion where two or more fine particles are stacked on the resist layer, A buffer material is applied on the fine particle layer, and the buffer material is cured while the imprint substrate is pressed on the buffer material to form a buffer layer.The replica substrate and the resist layer, the imprint substrate, the buffer The layer and the fine particle layer are separated.
[0013]
A method of manufacturing a recording medium according to still another aspect of the present invention includes forming a recording material layer on a medium substrate, forming a resist layer on the recording material layer, and pressing the imprint master on the resist layer. Transferring the concavo-convex shape of the fine particle layer on the surface of the imprint master to the resist layer, forming particles of a mask material in recesses formed in the resist layer, and using the particles of the mask material as a mask to form the resist layer and the recording layer. The method is characterized in that the material layer is patterned to form a patterned recording layer.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
In the recording medium according to the embodiment of the present invention, the recording material is not particularly limited, and for example, a magnetic recording material or an optical recording material that causes a phase change is used.
[0015]
FIG. 1 is a sectional view of a magnetic recording medium as an example of a recording medium according to an embodiment of the present invention. As shown in FIG. 1, the magnetic recording medium 10 has a structure in which a buffer layer 12 is formed on a medium substrate 11, and a magnetic recording layer 14 in which magnetic fine particles 13 are arranged is formed on the buffer layer 12. The magnetic recording layer 14 forms a surface substantially parallel to the surface of the medium substrate 11 on the surface, and has a portion where two or more layers of magnetic fine particles 13 are stacked from the surface in the depth direction of the buffer layer 12.
[0016]
On the surface of the magnetic recording layer 14, magnetic fine particles 13 having a two-dimensionally isotropic shape form a hexagonal lattice structure. Since the magnetic fine particles 13 have a dense structure with the highest density on the surface, a magnetic recording medium with a high recording density can be provided. As described later, the magnetic fine particles 13 arranged on the surface of the magnetic recording layer 14 may form a pattern corresponding to a track. In this magnetic recording medium 10, one-bit information may be recorded using a region including a plurality of magnetic fine particles as a recording cell, or information of one bit may be recorded using individual magnetic fine particles 13 as a recording cell. .
[0017]
The magnetic recording layer 14 includes a portion where two or more magnetic fine particles 13 are stacked in the depth direction of the buffer layer 12. The number of layers of the magnetic fine particles 13 in the layered portion of the magnetic fine particles 13 may be two, three, or more. The number of layers of the magnetic fine particles 13 does not need to be uniform, and the thickness of the magnetic recording layer 14 is not uniform. That is, the lower surface of the magnetic recording layer 14 (the interface with the buffer layer 12) has an irregular uneven structure. In the laminated portion, the magnetic fine particles 13 having a three-dimensionally isotropic shape are densely packed to form a face-centered cubic lattice structure or a hexagonal close-packed structure. When the magnetic recording layer 14 has a face-centered cubic lattice structure, a hexagonal lattice corresponding to the (111) plane in the face-centered cubic lattice structure appears on the surface of the magnetic recording layer 14.
[0018]
The buffer layer 12 below the magnetic recording layer 14 has a function of stably fixing the magnetic recording layer 14 on the medium substrate 11 having a flat surface. The magnetic recording layer 14 is fixed such that each of the magnetic fine particles 13 in contact with the buffer layer 12 is cut into the buffer layer 12. That is, the buffer layer 12 has a function of fixing the magnetic recording layer 14 having the lower surface of the irregular uneven structure to the medium substrate 11 having the flat surface.
[0019]
In the magnetic recording medium 10 according to one embodiment of the present invention, since the magnetic recording layer 14 is formed by arranging not the single layer but the multilayer magnetic fine particles 13 in a close-packed structure, the lower magnetic fine particles 13 By interacting with the magnetic fine particles on the surface, the recording magnetic field strength and storage stability of the magnetization information recorded on the magnetic fine particles on the surface can be changed. That is, by adjusting the thickness of the fine particle layer at the time of forming the fine particle layer, an ideal recording magnetic field strength can be given to the obtained medium.
[0020]
An example of a method for manufacturing a magnetic recording medium according to an embodiment of the present invention will be specifically described with reference to cross-sectional views shown in FIGS.
[0021]
First, as shown in FIG. 2A, a resist 22 is prepared by applying a resist 22 on a flat replica substrate 21 and forming grooves 23 corresponding to tracks on the surface of the resist 22. The groove 23 on the surface of the resist 22 can be formed by a method using an imprint master having projections corresponding to the groove or a lithography method.
[0022]
In FIG. 2A, the grooves 23 are formed to control the arrangement of the magnetic fine particles formed on the resist 22 in the next step. However, instead of the grooves 23, a chemically modified pattern corresponding to the track is formed. May be. When the magnetic fine particles are formed on the entire surface of the medium, it is not necessary to form the groove 23 or the chemical modification pattern.
[0023]
As shown in FIG. 2B, a magnetic recording layer 14 having a multilayer structure having a portion where two or more magnetic fine particles 13 are laminated is formed on the resist 22. Since the grooves corresponding to the tracks are formed on the surface of the replica substrate 21, the magnetic fine particles 13 are arranged with the axes of the hexagonal lattice aligned with the grooves to form a flat structure in the grooves. On the surface of the portion where two or more layers are stacked, a flat structure is not obtained due to the variation in thickness.
[0024]
This step is performed by, for example, a wet process in which a solvent in which magnetic fine particles are dispersed is applied on the replica and then the solvent is volatilized, or a dry process in which the magnetic fine particles themselves are sprayed on the replica surface together with a carrier gas. At this time, the conditions are adjusted so that two or more layers of the magnetic fine particles 13 are stacked, but it is not necessary to control the layer thickness. By using such a method, the magnetic recording layer 14 can be formed more quickly and easily than a method of reliably forming a single-layer film such as an LB method or an epitaxy method under ultrahigh vacuum. In addition, it is very difficult to cover the surface of the replica by densely arranging only one layer of magnetic fine particles because of the problem of aggregation of the magnetic fine particles 13. Even if the fine particles 13 aggregate, the magnetic fine particles 13 can be densely arranged on the surface of the replica. For this reason, a structure in which defects and depletion of the magnetic fine particles 13 hardly exist on the surface of the magnetic recording layer 14 is obtained.
[0025]
As shown in FIG. 2 (C), a liquid buffer material 12a is applied on the magnetic recording layer 14 and penetrates into the gaps between the magnetic fine particles 13 constituting the magnetic recording layer 14. The buffer material has a property of being solidified by heat or light irradiation.
[0026]
As shown in FIG. 2D, the medium substrate 11 is placed on the buffer material 12a, and the buffer material 12a is solidified by heating or light irradiation to form the buffer layer 12, and the magnetic recording layer 14 is fixed.
[0027]
The medium substrate 11 is not particularly limited as long as it has a thickness capable of holding the buffer layer 12 and the magnetic recording layer 14. In the above-described process, the medium substrate 11 is placed on the buffer material 12a, and the medium substrate 11 and the replica substrate 21 are pressed in parallel using, for example, a hydraulic press, and the buffer material 12a is solidified by heating to form a buffer. This is performed by forming the layer 12. As a result, the medium substrate 11 and the surface of the magnetic recording layer 14 are kept parallel.
[0028]
Thereafter, when the medium substrate 11 is separated from the replica substrate 21, the magnetic recording layer 14 is fixed to the buffer layer 12. As a result, the magnetic recording medium 10 in which the buffer layer 12 and the magnetic recording layer 14 are formed on the medium substrate 11 is obtained (FIG. 2E). Although the interface between the magnetic recording layer 14 and the buffer layer 12 is not flat, the surface of the magnetic recording layer 14 is flat and parallel to the medium substrate 11, and the magnetic fine particles 13 form a pattern corresponding to the track. ing. Therefore, information can be written and read stably on the surface of the magnetic recording layer 14.
[0029]
Further, the obtained interface between the magnetic recording layer 14 and the buffer layer 12 is not flat, and has an uneven structure reflecting the variation in the number of magnetic recording layers. This concavo-convex structure has the feature of increasing the adhesion between the magnetic recording layer 14 and the buffer layer 12, and can prevent the magnetic recording layer 14 from peeling off from the buffer layer 12.
[0030]
As described above, a magnetic recording layer having a multilayer structure can be formed by a simple process without the need to adjust the thickness of the magnetic fine particles, so that a magnetic recording medium (patterned medium) having a magnetic recording layer in which magnetic fine particles are arranged can be manufactured at low cost. can do.
[0031]
Next, an imprint master according to another embodiment of the present invention includes an imprint substrate, a buffer layer formed on the imprint substrate, and fine particles formed on the buffer layer arranged in a hexagonal lattice. Forming a surface substantially parallel to the imprint surface, and a fine particle layer having a portion where two or more fine particles are stacked from the surface in the depth direction of the buffer layer.
[0032]
This imprint master has the same structure as that of FIG. 1 except that a material suitable for the imprint master is used as the material of the imprint substrate and the material of the fine particles. Therefore, the surface of the fine particle layer formed on the imprint master via the buffer layer is flat with a structure in which the fine particles are arranged with almost no defects or depletion. The fine particle layer on the imprint master has a multilayer structure of fine particle layers. The multilayer structure of the fine particle layer has a structure in which the strength is increased in the thickness direction as compared with the single layer structure of the fine particle layer. Therefore, even if pressure is applied to the fine particles on the surface during imprinting, the multilayer structure of the fine particles is not deformed, and the fine particles can be used stably as an imprint master.
[0033]
Further, the interface between the obtained imprint master and the buffer layer is not flat, and has an uneven structure reflecting the variation in the number of fine particle layers. This uneven structure has a feature of increasing the adhesion between the imprint master and the buffer layer, and can prevent the fine particle layer from peeling off from the buffer layer.
[0034]
The fine particle layer is for changing the surface shape of the resist layer by pressing its surface structure against the resist layer surface. That is, the fine particles forming the fine particle layer need to be formed of a hard material harder than the resist material forming the resist layer. Specifically, the material of the hard fine particles forming the hard fine particle layer is preferably a metal, an alloy, a metal oxide, an inorganic material, a ceramic material, a semiconductor, a glass, or a compound or mixture thereof.
[0035]
The method for manufacturing an imprint master according to another embodiment of the present invention includes forming a resist layer on a replica substrate, dispersing fine particles on the resist layer, and forming a fine particle layer having a portion where two or more fine particles are stacked. Forming a buffer layer by applying a buffer material on the fine particle layer, curing the buffer material while pressing the imprint substrate on the buffer material, forming a buffer layer, the replica substrate and the resist layer, and the imprint substrate. , The buffer layer and the fine particle layer.
[0036]
Such a method can be carried out in the same manner as in FIGS. 2A to 2E, except that a material suitable for the imprint master is used as the material of the imprint substrate and the material of the fine particles. Therefore, a fine particle layer having a multilayer structure can be formed by a simple process that does not require uniform thickness of the fine particles, and an imprint master having a fine particle layer in which the fine particles are arranged can be manufactured at low cost.
[0037]
A method of manufacturing a recording medium according to still another embodiment of the present invention includes forming a recording material layer on a medium substrate, forming a resist layer on the recording material layer, and pressing the imprint master on the resist layer. The concave and convex shape of the fine particle layer on the surface of the imprint master is transferred to the resist layer, the particles of the mask material are formed in the concave portions formed in the resist layer, and the resist layer and the recording material layer are patterned using the particles of the mask material as a mask. To form a patterned recording layer.
[0038]
In order to form particles of the mask material in the concave portions formed in the resist layer, a method of applying a mask material typified by, for example, spin-on glass (SOG) and then performing a heat treatment can be used.
[0039]
SOG is a Si-containing polymer such as polysilane or polysiloxane. After being formed into a film by spin casting or the like in a state of being dissolved in a solution, SiOG is formed by annealing or the like. ₂ It is a material that changes to
[0040]
When this mask material is dissolved in an appropriate solvent and spin-coated on a patterned resist substrate, the dissolved solution of the mask material is planarized so as to selectively fill the concave portions on the resist substrate by surface tension. Thereafter, by performing an annealing process, the solvent can be volatilized from the mask material solution, and the mask material can be selectively deposited in the concave portions of the resist substrate.
[0041]
By using such an imprint method, a recording medium can be manufactured simply and inexpensively.
[0042]
In the method described above, a replica substrate for manufacturing an imprint master may be a medium substrate on which a recording material layer and a resist layer are formed. In this case, fine particles are sprayed on the resist layer formed on the medium substrate to form a fine particle layer having a portion where two or more fine particles are laminated, a buffer material is applied on the fine particle layer, and the buffer material is coated on the fine particle layer. When the buffer material is cured while the imprint substrate is pressed to form a buffer layer, the surface shape of the fine particle layer is transferred to the surface of the resist layer formed on the medium substrate. Thereafter, when the imprint master having the structure of imprint substrate / buffer layer / fine particle layer is peeled off, the structure of medium substrate / recording material layer / resist layer remains, and a concave portion corresponding to the surface shape of the fine particle layer is formed on the resist layer surface. Is done. Therefore, by forming particles of a mask material in the recesses formed in the resist layer, patterning the resist layer and the recording material layer using the particles of the mask material as a mask, and forming a patterned recording layer, a recording medium can be obtained. Can be manufactured.
[0043]
By using such a method, an imprint master and a medium substrate having a resist layer in which a concave portion corresponding to the surface shape of the fine particle layer on the surface of the imprint master can be simultaneously manufactured in a single procedure. , One recording medium can be manufactured. Therefore, the number of imprints can be reduced by one when manufacturing a recording medium using the obtained imprint master.
[0044]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
[0045]
Example 1
An embodiment of the present invention will be described with reference to FIGS. 3 (A) to 3 (D) and FIGS. 4 (E) to 4 (H).
[0046]
A resist 32 was spin-coated on a glass imprint master 31 (FIG. 3A). A resist pattern 33 having a spiral convex (peak) structure with a pitch of about 300 nm and a width of about 200 nm was formed by optical lithography (FIG. 3B). Using the resist pattern 33 as a mask, the imprint master 31 was etched by RIE to form a spiral convex structure 34 having a pitch of about 300 nm and a width of about 200 nm on the surface thereof. After that, the remaining resist pattern 33 was removed. Further, the surface of the imprint master 31 having the convex structure 34 was subjected to a hydrophobic treatment with hexamethyldisilazane (FIG. 3C).
[0047]
Next, a resist 22 was spin-coated on the glass replica substrate 21. After the convex structure 34 of the imprint master 31 was pressed against the surface of the resist 22 and pressed at a pressure of 1000 bar, the imprint substrate 31 was peeled off. The resist 22 on the replica substrate 21 was irradiated with UV light and annealed in a nitrogen atmosphere at 200 ° C. for 30 minutes to cure the resist 22. When the surface of the resist 22 on the replica substrate 21 was observed with an atomic force microscope (AFM), the convex structure 34 of the imprint master 31 was transferred, and a spiral having a pitch of about 300 nm and a depth of about 20 nm having a width of about 200 nm was formed. It was confirmed that the groove 23 was formed (FIG. 3D).
[0048]
In this embodiment, FePt fine particles obtained by the following method are used as the magnetic particles, but the material and the manufacturing method are not limited thereto.
[0049]
1,2-hexadecanediol powder as a reducing agent, platinum bisacetylacetonate Pt (acac) in 20 ml of octyl ether ₂ Oleic acid, oleylamine, Fe (CO) ₅ Was added. The temperature was raised to 280 ° C. where the solution boils and refluxed for 30 minutes. After the obtained solution was centrifuged and observed by TEM, FePt fine particles having a diameter of about 10 nm were observed. The FePt fine particles were dispersed in a 1-dodecanethiol ethanol solution, and the surfaces of the FePt fine particles were coated with 1-dodecanethiol. The FePt fine particles were collected by a centrifugal separator and dispersed in toluene to obtain a fine particle dispersion.
[0050]
As shown in FIG. 4 (E), the fine particle dispersion was sprayed on a resist 22 having a groove 23 on the replica substrate 21, and toluene was gradually evaporated. A cross section of the replica substrate 21 was observed with a cross section TEM. As a result, it was confirmed that the magnetic recording layer 14 was filled with the FePt fine particles 13 in the groove 23 of the resist 22 and further had a portion where two or more layers of FePt fine particles 13 were stacked on the entire surface. The thickness of the magnetic recording layer 14 (the thickness from the deepest part of the groove 23 to the surface) was about 40 nm, and it was confirmed that four layers of FePt fine particles 13 were stacked on average. However, the FePt fine particles 13 were partially formed into five or three layers, and variations in the layer thickness were observed.
[0051]
As shown in FIG. 4F, a resist 12a was spin-coated on the magnetic recording layer 14 as a buffer material. Observation of the cross section of the resist 12 a with a cross-sectional TEM confirmed that the resist 12 a penetrated into the gaps between the FePt fine particles 13 constituting the magnetic recording layer 14 and covered the entire surface of the replica substrate 21.
[0052]
As shown in FIG. 4 (G), the medium substrate 11 is placed on the resist 12a, and the medium substrate 11 and the replica substrate 21 are pressed using a hydraulic press at a pressure of 1000 bar and 200 ° C. for 1 minute to cure the resist. Thus, a buffer layer 12 was formed.
[0053]
Thereafter, the magnetic recording layer 14 on the surface of the replica substrate 21 is separated to the buffer layer 12 by peeling the medium substrate 11 from the replica substrate 21. As a result, the magnetic recording medium 10 in which the buffer layer 12 and the magnetic recording layer 14 are formed on the medium substrate 11 is obtained (FIG. 4H).
[0054]
A spiral convex structure having a pitch of about 300 nm and a width of about 200 nm was observed on the surface of the magnetic recording medium 10. On the outermost surface of the convex structure having a width of about 200 nm, it was confirmed that the FePt fine particles 13 were arranged in a hexagonal lattice with a lattice spacing of about 10 nm with the crystal axes aligned in the spiral track direction. The thickness of the magnetic recording layer 14 was equivalent to the average of four layers of FePt fine particles 13, but the FePt fine particles 13 were partially three or five layers, and variation in the layer thickness was confirmed. Was. It was confirmed that the magnetic recording layer 14 and the buffer layer 12 were in contact with each other in an uneven shape corresponding to the unevenness of the FePt fine particles 13 at the interface between them.
[0055]
In the obtained magnetic recording medium 10, since the magnetic recording layer 14 is formed by arranging the magnetic fine particles 13 not in a single layer but in multiple layers in a close-packed structure, the magnetic fine particles in the lower layer are different from the magnetic fine particles on the surface. Due to the interaction, the magnetic stability of the medium could be increased as compared to a recording medium in which the surface magnetic fine particles consisted of a monomolecular layer. Further, no peeling of the magnetic fine particle layer was confirmed.
[0056]
Further, by using the above-described method, the magnetic recording layer 14 having a multilayer structure can be formed by a simple process without having to make the thickness of the magnetic fine particles 13 uniform. Media can be manufactured at low cost.
[0057]
Example 2
Another embodiment of the present invention will be described with reference to FIGS.
Instead of the FePt fine particles used in Example 1, TiO having a particle size of about 10 nm was prepared as hard fine particles as follows. ₂ Fine particles were prepared. TiCl in ethanol ₄ Was dissolved at 2 mol / l, and then methanol was added to obtain a titanium alkoxide containing 50 mg / ml titanium. After hydrolysis, the aqueous solution was centrifuged and observed by TEM. ₂ Fine particles were observed. TiO ₂ A buffer layer 52 made of resist and a TiO 2 layer were formed on an imprint substrate 51 made of glass by the same method as in Example 1 except that fine particles were used. ₂ An imprint master 50 having a structure in which a fine particle layer 54 having a multilayer structure in which the fine particles 53 are arranged was formed (FIG. 5A). On the surface of the imprint master 50, a spiral convex structure having a width of about 200 nm is formed at a pitch of about 300 nm, and TiO is formed on the outermost surface of the convex structure having a width of about 200 nm. ₂ The fine particles 53 are arranged in a hexagonal lattice with a lattice spacing of about 10 nm with the crystal axes aligned in the spiral track direction.
[0058]
On the other hand, a CoCrPt layer 62 having a thickness of about 50 nm is formed as a perpendicular magnetic recording material on a medium substrate 61, and an SiO film having a thickness of about 50 nm is formed thereon. ₂ The layer 63 was formed. A resist 64 was spin-coated thereon (FIG. 5B).
[0059]
The fine particle layer 54 of the imprint master 50 shown in FIG. 5A was pressed against the surface of the resist 64 and pressed at a pressure of 1000 bar, and then the imprint master 50 was peeled off. When the surface of the resist 64 was observed by AFM, it was confirmed that the convex shape of the surface of the fine particle layer 54 of the imprint master 50 was transferred and a concave portion was formed (FIG. 5C). No film peeling of the fine particle layer was confirmed during imprinting.
[0060]
When spin-on glass (SOG) was applied on the resist 64 and heat-treated at 200 ° C. for 30 minutes, SOG dots 65 were formed corresponding to the concave portions of the resist 64 (FIG. 5D).
[0061]
Using the SOG dots 65 as a mask, resist 64, SiO ₂ The layer 63 and the CoCrPt layer 62 were etched to form a magnetic recording layer 66 composed of patterned CoCrPt particles (FIG. 5E).
[0062]
Next, an SiO film having a thickness of about 50 nm ₂ Is formed and then polished by chemical mechanical polishing (CMP), so that SiO is formed in the gaps between the CoCrPt particles constituting the magnetic recording layer 66. ₂ Was embedded to form a matrix 67, and the magnetic recording medium 60 was manufactured (FIG. 5F).
[0063]
Observation of the surface of the magnetic recording medium 60 thus manufactured by a magnetic force microscope confirmed that CoCrPt particles were arranged in a hexagonal lattice structure within a range of about 200 nm in width corresponding to a track. Was.
[0064]
In this embodiment, a magnetic recording medium (patterned medium) in which the magnetic recording layer is patterned by the imprint method can be manufactured using an imprint master manufactured by a simpler and less expensive method than before. In addition, the manufacturing cost of patterned media can be significantly reduced.
[0065]
Example 3
A further embodiment of the present invention will be described with reference to FIGS.
On a medium substrate 61, a CoCrPt layer 62 having a thickness of about 50 nm is formed as a perpendicular magnetic recording material. ₂ The layer 63 was formed. A resist 64 was spin-coated thereon (FIG. 6A). In this embodiment, the medium substrate 61 is also used as a replica substrate for producing an imprint master.
[0066]
On the other hand, TiO having a particle size of about 10 nm ₂ Fine particles are dispersed and TiO ₂ The surface of the fine particles was coated with 1-dodecanethiol. TiO in the centrifuge ₂ The fine particles were collected and dispersed in toluene to obtain a fine particle dispersion.
[0067]
The fine particle dispersion was sprayed on the resist 64 formed on the medium substrate 61, and toluene was gradually evaporated. Observation of the cross section of the medium substrate 61 with a cross section TEM revealed that two or more layers of TiO ₂ A fine particle layer 54 having a portion where the fine particles 53 were laminated was confirmed. The thickness of the fine particle layer 54 is about 40 nm, and four layers of TiO ₂ It was confirmed that the fine particles 53 were stacked. However, in part, TiO ₂ The fine particles 53 have five layers or three layers, and a variation in the layer thickness was observed (FIG. 6B).
[0068]
A resist 52a was spin-coated as a buffer material on the fine particle layer 54. Observation of the cross section of the resist 52a with a cross-sectional TEM showed that the resist 52a ₂ It was confirmed that it penetrated into the gaps between the fine particles 53 and covered the entire surface of the medium substrate 11 (FIG. 6C).
[0069]
The imprint substrate 51 is placed on the resist 52a, and the imprint substrate 51 and the medium substrate 61 are pressed using a hydraulic press at a pressing pressure of 1000 bar and 200 ° C. for 1 minute to cure the resist 52a to form the buffer layer 52. (FIG. 6D). At this time, the lower surface of the fine particle layer 54 is pressed against the surface of the resist 64 formed on the medium substrate 61, and the surface shape of the fine particle layer 54 is transferred to the surface of the resist 64. No peeling of the fine particle layer from the imprint substrate during imprinting was confirmed.
[0070]
Next, when the imprint substrate 51 is peeled from the medium substrate 61, the fine particle layer 54 is fixed to the buffer layer 52, and an imprint master 50 having a structure of imprint substrate 51 / buffer layer 52 / fine particle layer 54 is obtained. On the other hand, the medium substrate 61 / CoCrPt layer 62 / SiO ₂ The layer 63 / resist 64 remained, and a concave portion corresponding to the surface shape of the metal layer 54 was formed on the surface of the resist 64 (FIG. 6E).
[0071]
On this medium substrate 61, the SOG dots are formed in the resist concave portions and the SiOG using the SOG dots as a mask is formed in accordance with the same steps as in FIG. ₂ A magnetic recording medium (patterned medium) was manufactured by forming a magnetic recording layer by etching the layer 63 / CoCrPt layer 62, forming a matrix material, and planarizing by CMP. Further, using the imprint master 50, a new magnetic recording medium (patterned medium) could be manufactured according to the same steps as in FIGS. 5A to 5F of Example 2.
[0072]
【The invention's effect】
As described in detail above, according to the present invention, a patterned recording medium that can be manufactured by a simple and inexpensive method and that can write and read information stably, And a method that can be manufactured at low cost. Further, according to the present invention, an imprint master that can be manufactured by a simple and inexpensive method, a method by which such an imprint master can be easily and inexpensively manufactured, and a pattern formed by using the imprint master A method for manufacturing a recording medium can be provided.
[Brief description of the drawings]
FIG. 1 is a sectional view of a magnetic recording medium according to an embodiment of the present invention.
FIG. 2 is a sectional view showing the method of manufacturing the magnetic recording medium according to one embodiment of the present invention.
FIG. 3 is a sectional view showing the method for manufacturing the magnetic recording medium in the first embodiment.
FIG. 4 is a sectional view showing the method for manufacturing the magnetic recording medium in the first embodiment.
FIG. 5 is a sectional view showing the method for manufacturing the magnetic recording medium in the second embodiment.
FIG. 6 is a cross-sectional view illustrating a method for manufacturing an imprint master and a magnetic recording medium according to a third embodiment.
[Explanation of symbols]
10. Magnetic recording medium
11 Medium substrate
12a: buffer material
12 ... buffer layer
13: Magnetic fine particles
14 ... magnetic recording layer
21 ... Replica board
22 ... Resist
23 ... groove
31 ... Imprint master
32 ... Resist
33 ... Resist pattern
34 ... convex structure
50 ... Imprint master
51 ... imprint board
52 ... buffer layer
53 ... TiO ₂ Fine particles
54: Fine particle layer
60 ... magnetic recording medium
61 ... Media substrate
62 CoCrPt layer
63 ... SiO ₂ layer
64 ... Resist
65 ... SOG dots
66 ... magnetic recording layer
67 ... Matrix

Claims (5)

A medium substrate, a buffer layer formed on the medium substrate, and a recording layer containing recording material fine particles formed on the buffer layer, wherein the recording material fine particles are arranged in a hexagonal lattice and arranged. Forming a surface of the recording layer substantially parallel to a medium substrate surface, and having a portion in which two or more layers of the recording material fine particles are stacked from the surface in a depth direction of the buffer layer; recoding media. Form a resist layer on the replica substrate,
Spraying the recording material fine particles on the resist layer to form a recording layer having a portion where two or more recording material fine particles are laminated;
Applying a buffer material on the recording layer,
Forming a buffer layer by curing the buffer material while pressing a medium substrate on the buffer material,
2. The method according to claim 1, wherein the replica substrate and the resist layer are separated from the medium substrate, the buffer layer and the recording layer. An imprint substrate, a buffer layer formed on the imprint substrate, and a fine particle layer formed on the buffer layer, wherein the fine particle layer is formed by arranging fine particles in a hexagonal lattice and forming the imprint substrate. An imprint master, comprising: a surface substantially parallel to a print surface; and a portion in which two or more fine particles are stacked from the surface in a depth direction of the buffer layer. Form a resist layer on the replica substrate,
Forming a fine particle layer having a portion where two or more fine particles are laminated on the resist layer,
Applying a buffer material on the fine particle layer,
Forming a buffer layer by curing the buffer material while pressing the imprint substrate on the buffer material,
4. The method according to claim 3, wherein the replica substrate and the resist layer are separated from the imprint substrate, the buffer layer and the fine particle layer. Forming a recording material layer on a medium substrate,
Forming a resist layer on the recording material layer,
Pressing the imprint master according to claim 3 to the resist layer, and transferring the uneven shape of the fine particle layer on the surface of the imprint master to the resist layer,
Form particles of a mask material in the recesses formed in the resist layer,
A method for manufacturing a recording medium, comprising patterning the resist layer and the recording material layer using the particles of the mask material as a mask to form a patterned recording layer.

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