JP3766360B2 - Recording medium, method for manufacturing recording medium, imprint master, and method for manufacturing imprint master - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recording medium having a patterned recording layer, a manufacturing method thereof, an imprint master having a patterned metal layer, a manufacturing method thereof, 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]
With the dramatic improvement in functions of information devices such as personal computers, the amount of information handled by users has increased significantly. Under such circumstances, expectations for a magnetic recording medium and an optical recording medium having a recording density dramatically higher than before and a semiconductor device having a high degree of integration are 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 contained in a magnetic recording layer are made fine and magnetically separated from each other. In order to form such a magnetic recording layer containing fine magnetic particles separated from each other, a finer processing technique is required.
[0004]
That is, the conventional photolithography technique using the exposure process can perform microfabrication of a large area at a time, but does not have a resolution below the wavelength of light, and thus it is difficult to produce a microstructure with a thickness of about 100 nm or less. . On the other hand, there are techniques such as electron beam lithography and focused ion beam lithography as processing techniques at a level of 100 nm or less, but the problem is poor throughput. For this reason, there is a demand for a method capable of more easily producing patterned media having a fine pattern.
[0005]
As a technique for producing a fine structure with a wavelength equal to or less than the wavelength of light with high throughput, S. Y. Chou et al., Appl. Phys. Lett. , Vol. 76 (1995) p. There is a “nanoimprint lithography (NIL) technology” proposed in 3114. In the nanoimprint lithography technology, an imprint master having a predetermined fine concavo-convex pattern is prepared in advance by electron beam lithography or the like, and the imprint master is pressed against the substrate to which the resist is applied. This is a method of transferring to a resist film. In this method, the time required for one process can be very short as compared with electron beam lithography or focused ion beam lithography, for example, in an area of 1 square inch or more.
[0006]
Conventionally, the nanoimprint master is produced by using optical lithography, electron beam lithography, or focused ion beam lithography. However, when producing a nanoimprint master, problems similar to those of the above-mentioned patterned media are produced, and it is difficult to obtain a resolution of 100 nm or less by optical lithography. Throughput by electron beam lithography or focused ion beam lithography is difficult. The problem is the 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]
An object of the present invention is to provide a patterned recording medium that can be manufactured by a simple and inexpensive method, capable of stably writing and reading information, and a method that can manufacture such a recording medium simply and inexpensively. 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 using the imprint master. It is to provide a method for manufacturing a recording medium.
[0009]
[Means for Solving the Problems]
A recording medium according to an aspect 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, and the recording material Fine particles are arranged in a hexagonal lattice to form the surface of the recording layer substantially parallel to the surface of the medium substrate, and two or more recording material fine particles are formed from the surface toward the depth of the buffer layer. It has a laminated portion.
[0010]
The method for manufacturing a recording medium according to one aspect of the present invention includes a portion in which a resist layer is formed on a replica substrate, and recording material fine particles are dispersed on the resist layer so that two or more recording material fine particles are stacked. Forming a recording layer, applying a buffer material on the recording layer, forming a buffer layer by curing the buffer material in a state where a medium substrate is pressed on the buffer material, the replica substrate and a resist layer; The medium substrate, the buffer layer, and the recording layer are peeled off.
[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. The fine particles are arranged in a hexagonal lattice to form a surface substantially parallel to the imprint surface, and a portion in which two or more fine particles are laminated from the surface toward the depth of the buffer layer. It is characterized by.
[0012]
In the method for manufacturing an imprint master according to another aspect of the present invention, a resist layer is formed on a replica substrate, and a fine particle layer having a portion in which two or more fine particles are stacked is formed on the resist layer, A buffer material is applied on the fine particle layer, and the buffer material is cured by pressing the imprint substrate on the buffer material to form a buffer layer. The replica substrate, the resist layer, the imprint substrate, and the buffer The layer and the fine particle layer are peeled off.
[0013]
According to still another aspect of the present invention, there is provided a recording medium manufacturing method, comprising: 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. Then, the uneven shape of the fine particle layer on the surface of the imprint master is transferred to the resist layer, and the mask material particles are formed in the recesses formed in the resist layer. The resist layer and the recording are recorded using the mask material particles as a mask. The material layer is patterned to form a patterned recording layer.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
In the recording medium according to the embodiment of the present invention, the recording material is not particularly limited. For example, a magnetic recording material or an optical recording material that causes a phase change is used.
[0015]
FIG. 1 shows a cross-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 in which two or more magnetic fine particles 13 are laminated from the surface toward 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-dimensional 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 having a high recording density can be provided. As will be described later, the magnetic fine particles 13 arranged on the surface of the magnetic recording layer 14 may form a pattern corresponding to the track. In this magnetic recording medium 10, 1-bit information may be recorded using a region including a plurality of magnetic fine particles as a recording cell, or 1-bit information may be recorded using each magnetic fine particle 13 as a recording cell. .
[0017]
The magnetic recording layer 14 includes a portion in which two or more magnetic fine particles 13 are stacked in the depth direction of the buffer layer 12. The number of the magnetic fine particles 13 in the laminated portion of the magnetic fine particles 13 may be two, three, or more layers. The number of laminated 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 (interface with the buffer layer 12) has an irregular concavo-convex structure. In the laminated portion, magnetic fine particles 13 having a three-dimensional 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 in a state in which each of the magnetic fine particles 13 in contact with the buffer layer 12 is embedded in 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 concavo-convex structure to the medium substrate 11 having a flat surface.
[0019]
In the magnetic recording medium 10 according to an embodiment of the present invention, the magnetic recording layer 14 is formed by arranging not only a single layer but multiple layers of magnetic fine particles 13 in a close-packed structure. By interacting with the magnetic fine particles on the surface, the recording magnetic field strength and the storage stability of the magnetization information recorded on the magnetic fine particles on the surface can be changed. That is, by adjusting the film thickness of the fine particle layer when 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 applied on a flat replica substrate 21, and a groove 23 corresponding to a track is formed on the resist 22 surface. The groove 23 on the surface of the resist 22 can be formed by a method using an imprint master having a convex portion corresponding to the groove or a lithography method.
[0022]
In FIG. 2A, the grooves 23 are formed in order to control the arrangement of the magnetic fine particles formed on the resist 22 in the next step, but instead of the grooves 23, chemical modification patterns corresponding to the tracks are formed. May be. When magnetic fine particles are formed on the entire surface of the medium, it is not necessary to form grooves 23 or chemical modification patterns.
[0023]
As shown in FIG. 2B, a magnetic recording layer 14 having a multilayer structure having a portion in which two or more magnetic fine particles 13 are laminated is formed on a resist 22. Since the grooves corresponding to the tracks are formed on the surface of the replica substrate 21, the magnetic fine particles 13 form a flat structure in the grooves by arranging the hexagonal lattice axes in alignment with the grooves. The surface of the portion where two or more layers are stacked does not have a flat structure due to thickness variations.
[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 are sprayed onto the replica surface together with a carrier gas. At this time, the conditions are adjusted so that two or more magnetic fine particles 13 are laminated, but it is not necessary to control the layer thickness. If such a method is used, the magnetic recording layer 14 can be formed at a higher speed and more easily than a method of reliably producing a single layer film, such as an LB method or an epitaxy method under an ultrahigh vacuum. In addition, it is very difficult to cover the surface of the replica with only one layer of magnetic fine particles densely arranged due to the problem of aggregation of the magnetic fine particles 13. Even if the fine particles 13 are aggregated, the magnetic fine particles 13 can be densely arranged on the surface of the replica. Therefore, a structure in which defects and depletions of the magnetic fine particles 13 hardly exist on the surface of the magnetic recording layer 14 is obtained.
[0025]
As shown in FIG. 2C, a liquid buffer material 12 a is applied on the magnetic recording layer 14 and penetrates into the gaps of the magnetic fine particles 13 constituting the magnetic recording layer 14. The buffer material has a property of solidifying by heat or light irradiation.
[0026]
As shown in FIG. 2D, the medium substrate 11 is placed on the buffer material 12a, the buffer material 12a is solidified by heating or light irradiation, the buffer layer 12 is formed, 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 process, the medium substrate 11 is placed on the buffer material 12a, pressed using, for example, a hydraulic press machine so that the medium substrate 11 and the replica substrate 21 are parallel, and the buffer material 12a is solidified by heating to be buffered. This is done by forming 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 peeled 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 having the buffer layer 12 and the magnetic recording layer 14 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 stably written and read on the surface of the magnetic recording layer 14.
[0029]
Further, the interface between the obtained magnetic recording layer 14 and the buffer layer 12 is not flat, and has a concavo-convex structure reflecting the variation in the number of magnetic recording layers. This concavo-convex structure has a feature of improving the adhesion between the magnetic recording layer 14 and the buffer layer 12 and can suppress peeling of the magnetic recording layer 14 from the buffer layer 12.
[0030]
As described above, a magnetic recording layer with a multilayer structure can be formed by a simple process that does not require the thickness of the magnetic fine particles to be uniform. 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. And a fine particle layer having a portion in which two or more fine particles are laminated from the surface toward the depth of the buffer layer.
[0032]
This imprint master has the same structure as that shown in FIG. 1 except that a material suitable for the imprint master is used as the material for the imprint substrate and the material for the fine particles. Therefore, the surface of the fine particle layer formed on the imprint master through the buffer layer is flat with a structure in which the fine particles are arranged in a state where there are almost no defects or depletions. Further, the fine particle layer on the imprint master has a multilayer structure of fine particle layers. The multilayer structure of the fine particle layer is a structure in which the strength is increased in the film thickness direction as compared with the single layer structure of the fine particle layer. For this reason, even when the fine particles on the surface are subjected to pressure during imprinting, the multilayer structure of the fine particles is not deformed and can be used stably as an imprint master.
[0033]
Furthermore, the interface between the obtained imprint master and the buffer layer is not flat, and has a concavo-convex structure reflecting the variation in the number of fine particle layers. This concavo-convex structure has the characteristic of improving the adhesion between the imprint master and the buffer layer, and can prevent film peeling of the fine particle layer from the buffer layer.
[0034]
The fine particle layer is for changing the surface shape of the resist layer by pressing the surface structure against the surface of the resist layer. That is, the fine particles forming the fine particle layer must 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, glass, or a compound or a mixture thereof.
[0035]
The method for manufacturing an imprint master according to another embodiment of the present invention includes: a fine particle layer having a portion in which a resist layer is formed on a replica substrate, and fine particles are dispersed on the resist layer to laminate two or more fine particles. The buffer material is applied onto the fine particle layer, and the buffer material is cured by pressing the imprint substrate on the buffer material to form the buffer layer, and the replica substrate, the resist layer, and the imprint substrate The buffer layer and the fine particle layer are peeled off.
[0036]
Such a method can be carried out in the same manner as in FIGS. 2A to 2E except that an appropriate material for the imprint master is used as the material for the imprint substrate and the material for 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 fine particles are arranged can be manufactured at low cost.
[0037]
A method for 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 disc on the resist layer. The uneven shape of the fine particle layer on the surface of the imprint master is transferred to the resist layer, the mask material particles are formed in the recesses formed in the resist layer, and the resist layer and the recording material layer are patterned using the mask material particles as a mask. A patterned recording layer is formed.
[0038]
In order to form the particles of the mask material in the recesses formed in the resist layer, for example, a method of performing a heat treatment after applying a mask material typified by spin-on glass (SOG) or the like can be used.
[0039]
SOG is a Si-containing polymer such as polysilane or polysiloxane. After being formed on a substrate by a method such as spin casting in a state dissolved in a solution, SiOG is annealed or the like. ₂ It is a material that changes.
[0040]
When this mask material is dissolved in an appropriate solvent and spin-coated on a patterned resist substrate, the solution in which the mask material is dissolved is planarized so as to selectively fill the recesses on the resist substrate by surface tension. By performing an annealing process thereafter, the solvent can be volatilized from the mask material solution, and the mask material can be selectively deposited on the recesses of the resist substrate.
[0041]
By using such an imprint method, a recording medium can be manufactured easily and inexpensively.
[0042]
In the above-described method, a replica substrate for manufacturing an imprint master may be one in which a recording material layer and a resist layer are formed on a medium substrate. In this case, fine particles are dispersed on the resist layer formed on the medium substrate to form a fine particle layer having a portion in which 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 buffer material. When the buffer material is cured by pressing the imprint substrate and the buffer layer is formed, the surface shape of the fine particle layer is transferred to the surface of the resist layer formed on the medium substrate. After that, 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 recess corresponding to the surface shape of the fine particle layer is formed on the resist layer surface. Is done. Therefore, if the mask material particles are formed in the recesses formed in the resist layer, the resist layer and the recording material layer are patterned using the mask material particles as a mask, and the patterned recording layer is formed, the recording medium is obtained. Can be manufactured.
[0043]
By using such a method, it is possible to simultaneously produce an imprint master and a medium substrate having a resist layer in which a recess corresponding to the surface shape of the fine particle layer on the surface of the imprint master is formed in one procedure. By processing this, one recording medium can be manufactured. Therefore, the number of imprints can be saved once when a recording medium is manufactured 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 (D) and FIGS. 4 (E) to (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 photolithography (FIG. 3B). The imprint master 31 was etched by RIE using the resist pattern 33 as a mask, and a spiral convex structure 34 with a width of about 200 nm was formed on the surface thereof at a pitch of about 300 nm. Thereafter, the remaining resist pattern 33 was removed. Further, the surface of the imprint master 31 having the convex structure 34 was hydrophobized with hexamethyldisilazane (FIG. 3C).
[0047]
Next, a resist 22 was spin-coated on the glass replica substrate 21. The convex structure 34 of the imprint master 31 was pressed against the surface of the resist 22 and pressed with a pressure of 1000 bar, and then the imprint substrate 31 was peeled off. The resist 22 on the replica substrate 21 was irradiated with UV light and annealed at 200 ° C. for 30 minutes in a nitrogen atmosphere 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 depth of about 20 nm forming a spiral shape with a width of about 200 nm at a pitch of about 300 nm. It was confirmed that the groove 23 was formed (FIG. 3D).
[0048]
In this example, FePt fine particles obtained by the following method are used as the magnetic particles, but the material and manufacturing method are not limited thereto.
[0049]
20 ml of octyl ether, 1,2-hexadecanediol powder as a reducing agent, platinum bisacetylacetonate Pt (acac) ₂ And heated to 80 ° C., then oleic acid, oleylamine, Fe (CO) _Five Was added. The temperature was raised to 280 ° C. where the solution boiled, and refluxed for 30 minutes. When 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 an ethanol solution of 1-dodecanethiol, and the surface of the FePt fine particles was coated with 1-dodecanethiol. FePt fine particles were collected with a centrifuge and dispersed in toluene to obtain a fine particle dispersion.
[0050]
As shown in FIG. 4E, this fine particle dispersion was sprayed on the resist 22 having the grooves 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, the magnetic recording layer 14 having a portion in which the FePt fine particles 13 were filled in the grooves 23 of the resist 22 and two or more FePt fine particles 13 were laminated on the entire surface was confirmed. The thickness of the magnetic recording layer 14 (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 laminated on average. However, the FePt fine particles 13 were partially composed of five layers or three layers, and variations in layer thickness were observed.
[0051]
As shown in FIG. 4F, a resist 12a as a buffer material was spin coated on the magnetic recording layer. When the cross section of the resist 12a was observed with the cross section TEM, it was confirmed that the resist 12a penetrated into the gaps of 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. 4G, 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 machine at a pressure of 1000 bar and 200 ° C. for 1 minute to cure the resist. Thus, the buffer layer 12 was formed.
[0053]
Thereafter, by peeling the medium substrate 11 from the replica substrate 21, the magnetic recording layer 14 on the surface of the replica substrate 21 is separated toward the buffer layer 12. As a result, the magnetic recording medium 10 having the buffer layer 12 and the magnetic recording layer 14 formed on the medium substrate 11 is obtained (FIG. 4H).
[0054]
On the surface of the magnetic recording medium 10, a spiral convex structure having a pitch of about 300 nm and a width of about 200 nm was observed. On the outermost surface of the convex structure with 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 axis aligned in the spiral track direction. The thickness of the magnetic recording layer 14 was an average thickness corresponding to the four layers of FePt fine particles 13, but the FePt fine particles 13 were partially formed into three or five layers, and variations in the layer thickness were confirmed. It 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, the magnetic recording layer 14 is formed by arranging a plurality of magnetic fine particles 13 instead of a single layer in a close-packed structure. By having the interaction, the magnetization stability of the medium can be increased as compared with the recording medium in which the surface magnetic fine particles are composed of a monomolecular layer. Further, no peeling of the magnetic fine particle layer was confirmed.
[0056]
Further, if the method as described above is used, the magnetic recording layer 14 having a multilayer structure can be formed by a simple process that does not require the thickness of the magnetic fine particles 13 to be 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 diameter of about 10 nm prepared as hard fine particles as follows. ₂ Fine particles were prepared. TiCl in ethanol _Four Was dissolved in 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 TiO are 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 disc 50 having a structure in which a fine particle layer 54 having a multilayer structure in which fine particles 53 are arranged was produced (FIG. 5A). On the surface of the imprint master 50, a spiral convex structure having a pitch of about 300 nm and a width of about 200 nm is formed. On the outermost surface of the convex structure having a width of about 200 nm, TiO 2 is formed. ₂ The fine particles 53 are arranged in a hexagonal lattice with a lattice interval of about 10 nm with the crystal axis aligned in the spiral track direction.
[0058]
On the other hand, a CoCrPt layer 62 having a film thickness of about 50 nm is formed on the medium substrate 61 as a perpendicular magnetic recording material, and an SiO film having a film thickness of about 50 nm is formed thereon. ₂ 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 on the surface of the fine particle layer 54 of the imprint master 50 was transferred to form a concave portion (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 dot 65 as a mask, resist 64, SiO by Ar ion milling 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, a SiO film with a thickness of about 50 nm is formed on the entire surface. ₂ Is then polished by chemical mechanical polishing (CMP) to form SiO in the gaps between CoCrPt particles constituting the magnetic recording layer 66. ₂ Was embedded to form the matrix 67, and the magnetic recording medium 60 was manufactured (FIG. 5F).
[0063]
When the surface of the magnetic recording medium 60 thus manufactured was observed with a magnetic force microscope, it was confirmed that CoCrPt particles were arranged in a hexagonal lattice structure within a range of about 200 nm in width corresponding to the track. It was.
[0064]
In this embodiment, a magnetic recording medium (patterned media) in which a magnetic recording layer is patterned by an imprinting method can be produced using an imprinting master produced by a simpler and cheaper method than before. The manufacturing cost of patterned media can be greatly reduced.
[0065]
Example 3
Still another embodiment of the present invention will be described with reference to FIGS.
A CoCrPt layer 62 having a film thickness of about 50 nm is formed on the medium substrate 61 as a perpendicular magnetic recording material, and an SiO film having a film thickness of about 50 nm is formed thereon. ₂ 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 in an ethanol solution of 1-dodecanethiol. ₂ Fine particles are dispersed and TiO ₂ The surface of the fine particles was coated with 1-dodecanethiol. TiO in 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. When the cross section of the medium substrate 61 was observed with a cross section TEM, two or more layers of TiO 2 were formed on the entire surface of the resist 64. ₂ A fine particle layer 54 having a portion where the fine particles 53 were laminated was confirmed. The fine particle layer 54 has a thickness of about 40 nm, and an average of four TiO layers. ₂ It was confirmed that the fine particles 53 were laminated. However, in part TiO ₂ The fine particles 53 consist of five layers or three layers, and variation in the layer thickness was observed (FIG. 6B).
[0068]
On the fine particle layer 54, a resist 52a was spin coated as a buffer material. When the cross section of the resist 52a is observed with a cross section TEM, the resist 52a forms the fine particle layer 54 with TiO. ₂ It was confirmed that the fine particles 53 penetrated into the gaps 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 machine at a pressure of 1000 bar and 200 ° C. for 1 minute to cure the resist 52a, thereby forming 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 film 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 the imprint master disk 50 having the structure of the 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]
For this medium substrate 61, SOG dots are formed in the resist recesses and SiO is formed using the SOG dots as a mask according to the same steps as those 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 performing planarization by CMP. In addition, a new magnetic recording medium (patterned medium) could be manufactured by using the imprint master 50 according to the same steps as those 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 stably write and read information, and such a recording medium can be easily used. 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 that can easily and inexpensively manufacture such an imprint master, and a pattern using the imprint master A method for manufacturing a recording medium can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a magnetic recording medium according to an embodiment of the invention.
FIG. 2 is a cross-sectional view showing a method for manufacturing a magnetic recording medium according to an embodiment of the present invention.
3 is a cross-sectional view showing a method of manufacturing a magnetic recording medium in Example 1. FIG.
4 is a cross-sectional view showing a method of manufacturing a magnetic recording medium in Example 1. FIG.
5 is a cross-sectional view showing a method for manufacturing a magnetic recording medium in Example 2. FIG.
6 is a cross-sectional view showing a method for manufacturing an imprint master and a magnetic recording medium in Embodiment 3. FIG.
[Explanation of symbols]
10. Magnetic recording medium
11 ... Media 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 substrate
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 dot
66 ... Magnetic recording layer
67 ... Matrix

Claims (5)

A medium substrate; a buffer layer formed on the medium substrate; and a recording layer including recording material fine particles formed on the buffer layer, wherein the recording material fine particles are arranged in a hexagonal lattice, and A surface of the recording layer that is substantially parallel to the surface of the medium substrate is formed, and a portion in which two or more recording material fine particles are stacked from the surface in the depth direction of the buffer layer is provided. recoding media. Forming a resist layer on the replica substrate;
The recording material fine particles are dispersed on the resist layer to form a recording layer having a portion in which two or more recording material fine particles are laminated,
Applying a buffer material on the recording layer,
A buffer layer is formed by curing the buffer material in a state where a medium substrate is pressed on the buffer material;
The method for manufacturing a recording medium 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 includes fine particles arranged in a hexagonal lattice to form the imprint substrate. An imprinting master having a surface that forms a surface substantially parallel to the printed surface and in which two or more fine particles are laminated from the surface toward the depth of the buffer layer. Forming a resist layer on the replica substrate;
Forming a fine particle layer having a portion in which two or more fine particles are laminated on the resist layer;
Applying a buffer material on the fine particle layer;
A buffer layer is formed by curing the buffer material in a state where an imprint substrate is pressed on the buffer material;
4. The method for producing an imprint master according to claim 3, wherein the replica substrate and the resist layer are peeled from the imprint substrate, the buffer layer, and the fine particle layer. Forming a recording material layer on the medium substrate;
Forming a resist layer on the recording material layer;
The imprint master according to claim 3 is pressed on the resist layer to transfer the irregular shape of the fine particle layer on the surface of the imprint master to the resist layer,
Forming particles of mask material in the recesses formed in the resist layer;
A method of manufacturing a recording medium, wherein 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.

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