JP2004062995A - Substrate for vertical magnetic recording medium and its manufacturing method, and vertical magnetic recording medium and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for a vertical magnetic recording medium being superior in flatness, patterning accuracy, and mechanical strength, and its manufacturing method, and a vertical magnetic recording medium using the substrate and its manufacturing method. <P>SOLUTION: Surface layers of thermoplastic resin such as polycarbonate, polymethylmethacrylate, or the like are laminated, this surface layer is heated, a stamper in which a desired uneven pattern is formed is pressed, the pattern is transferred, and a substrate for vertical magnetic recording medium is made. Also, after a magnetic layer is formed on a whole surface of the surface layer of this substrate, a magnetic layer on the projecting part of the surface layer is removed, a base layer consisting of metal of hexagonal fine packing structure or its alloy or metal of face-centered cubic lattice structure or its alloy and a CoCrPt group magnetic recording layer, a granular magnetic recording layer, an RE-TM group alloy layer or a magnetic recording layer of a lamination film of Co/P or Co/Pd or the like are formed on only on the recessed part of the surface layer, and the vertical magnetic recording medium is made. <P>COPYRIGHT: (C)2004,JPO

Description

【００４５】
ここで、平坦度は、基板中心から半径方向へ１１ｍｍから３０ｍｍまでの直線領域に関して基板表面形状の変位量を非接触光学式表面粗さ計にて真直度を求めた。具体的には、各基板について、円周方向に９０°おきに４箇所の測定を行い、その中で最大の真直度をその基板面の平坦度とした。
【００４６】
また、転写率は、パターンの設計値φ１００ｎｍ×深さ５０ｎｍに対して、±５％以内の誤差を合格その他を不合格とし、評価したパターン１００個のうち合格したパターンの割合を転写率とした。なお、この評価にはＡＦＭ（原子間力顕微鏡）を用いた。
【００４７】
平坦度に関しては、実施例１の垂直磁気記録媒体用基板は、支持基体として用いたガラスディスクの平坦性をそのまま反映して１μｍであった。比較例１の射出成型で作製したプラスチック基板は、板厚を厚くすると平坦度が小さくなる傾向が認められるものの、最も平坦性に優れる板厚１．２ｍｍのものでも実施例１の垂直磁気記録媒体用基板に比べると非常に大きい。
【００４８】
また、転写率に関しては、実施例１では１００％の確率が得られたのに対し、比較例１では全ての板厚で８０〜８４％に留まっており、本発明の優位性が確認された。
【００４９】
このように、本発明によれば、平坦性に優れ、かつ、パターンの転写性にも優れた垂直磁気記録媒体用基板が作製できることがわかる。また、射出成型により作製される熱可塑性樹脂基板では困難な薄型化が可能であることもわかる。
【００５０】
実施例２及び比較例２〜４については、垂直磁気記録媒体の保磁力と、磁気ヘッドのＧｌｉｄｅ　Ｈｉｇｈｔ特性（Ｇ．Ｈ．特性）について評価した。その結果を表２に示す。
【００５１】
【表２】

【００５２】
ここで、保磁力はＶＳＭで得られたＭ‐Ｈループより求めた。Ｇ．Ｈ．特性試験は、回転させた媒体の上に試験用のへッドを飛ばし、媒体表面の突起、パーティクル、うねり等を検知するもので、試験条件は、周速７ｍ／ｓｅｃ、Ｇ．Ｈ．１２．５ｎｍとし、各々１００枚ずつ評価を行って合格率を求めた。
【００５３】
まず、保磁力の評価結果について説明する。磁気記録層が連続膜になっている比較例４の垂直磁気記録媒体の保磁力は４１０Ｏｅと小さく、磁性粒間の相互作用が非常に大きくなっていることがわかる。これに比ベ、磁気記録層がパターニングされている実施例２、比較例２及び３の垂直磁気記録媒体の各々は大きな保磁力を示している。このことから、実施例２、比較例２及び３の垂直磁気記録媒体の磁性粒間の相互作用が小さいこと、すなわちｂｉｔが物理的に分離していることが確認できる。
【００５４】
ただし、比較例２と３の垂直磁気記録媒体の保磁力は、実施例２の垂直磁気記録媒体の保磁力に比ベて小さい。また、比較例２と３の垂直磁気記録媒体を比較すると、基板厚さの薄い比較例２の方が保磁力が小さい。
【００５５】
この結果と上述の比較例２及び３の平坦性及びパターン転写率が低いことを併せて考えると、実施例１に比べ比較例２及び３では基板表面の平坦性が低いために研磨の正確度が低下して磁気的に繋がったビットが存在することや、パターンの転写率が低く形状にばらつきが多く存在することがわかる。
【００５６】
Ｇ．Ｈ．試験特性の評価結果をみると、実施例１の垂直磁気記録媒体では、パターニングを施さない比較例４の垂直磁気記録媒体とほぼ同等の合格率であり、研磨等の工程を経た後でも優れた基板表面特性を示すことが分かる。これに対して、既に説明したように、基板作製後に平坦性の低い比較例２及び３の垂直磁気記録媒体は、この試験をほとんど合格することができないことから、パターンド記録媒体とした後もそれを反映した結果となることがわかる。
【００５７】
【発明の効果】
以上述べたように、本発明によれば、アルミまたはガラス等の支持基板（支持層）上に、ポリカーボネートまたはポリメタクリル酸メチル等の熱可塑性樹脂の表面層を積層し、この表面層を加熱して所望のパターンが形成されているスタンパを押し付けて凹凸パターンを転写することとしたので、基板にとって重要な平滑性を確保しつつ表面に凹凸パターンを備えた垂直磁気記録媒体用基板を提供することができ、かつ、基板の薄型化も可能となる。
【００５８】
また、本発明の垂直磁気記録媒体用基板を用いることにより、優れた表面形状のパターンド垂直磁気記録媒体を提供することが可能となる。
【図面の簡単な説明】
【図１】本発明の垂直磁気記録媒体用基板の構成を説明するための図である。
【図２】本発明の垂直磁気記録媒体用基板の製造方法を説明するための図である。
【図３】本発明の垂直磁気記録媒体の構造を説明するための図である。
【符号の説明】
１１　支持基体
１２　表面層
１３　スタンパ
１４　下地層
１５　磁気記録層
１６　保護膜
１７　液体潤滑層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a substrate for a perpendicular magnetic recording medium and a method for manufacturing the same, and a perpendicular magnetic recording medium and a method for manufacturing the same. More specifically, the present invention relates to a substrate for a perpendicular magnetic recording medium having excellent flatness, patterning accuracy and mechanical strength, and a method for manufacturing the same. The present invention relates to a manufacturing method, a perpendicular magnetic recording medium using the substrate, and a manufacturing method thereof.
[0002]
[Prior art]
As is well known, a magnetic recording medium is provided with address information by a servo signal written by a servo writer. Therefore, when narrowing the recording track width for the purpose of increasing the recording density, it is necessary to increase the accuracy of servo signals and tracks. For this purpose, a high positional accuracy between the servo writer and the medium driving device is required, so that the device becomes expensive, and writing of a servo signal by the servo writer requires several minutes per medium. These restrictions are an obstacle to improving the mass productivity of magnetic disks.
[0003]
In order to overcome such a problem, it has been proposed to provide a servo signal and a track on a medium in advance. For example, in Japanese Patent Application Laid-Open No. 5-6535, a servo pattern of a mold is formed by an injection molding method. There has been proposed a recording medium using a plastic substrate onto which is transferred.
[0004]
On the other hand, with respect to increasing the recording density, for example, Japanese Patent Application Laid-Open No. H11-185291 discloses the invention of a high-density recording medium in which a recording layer is formed on a sheet-like substrate having an uneven pattern formed on the surface. In order to further increase the recording density, a patterned recording medium in which recording bits are physically separated has been proposed in place of the conventional continuous film type magnetic recording layer.
[0005]
A typical method for producing a patterned medium is as follows.
[0006]
First, a continuous magnetic recording layer is formed on a substrate, a resist is applied thereon, and a pattern is drawn by electron beam lithography. Next, after forming a mask film, the resist is removed, and the unmasked portion is removed by RIE (Reactive Ion Etching), and then the mask film is removed. Through these steps, a patterned magnetic recording layer is obtained.
[0007]
Although the patterned recording medium manufactured by such a method achieves a high recording density, it has a problem that productivity is low because the above-described complicated steps are required.
[0008]
On the other hand, as a method of manufacturing a recording medium with higher productivity, there is a method of embedding a magnetic material in a pattern of a substrate which has been previously patterned into a patterned recording medium. As such a substrate, there is a plastic substrate patterned by injection molding, and a servo pattern or a bit pattern can be formed easily and inexpensively by injection molding.
[0009]
[Problems to be solved by the invention]
However, the method of patterning a plastic substrate by injection molding has the following two major problems.
[0010]
One of them is that when transferring high-precision patterns, it is necessary to set the mold temperature and the mold clamping pressure high. When the mold temperature is increased, the substrate is taken out of the mold and cooled to room temperature. There is a problem that a temperature difference at the time of performing the heat treatment becomes large, and thermal stress remains on the substrate, thereby reducing the flatness of the substrate. This is the same when the mold clamping pressure is increased. That is, improving the flatness of the substrate and transferring a fine pattern to the substrate are not compatible.
[0011]
On the other hand, a plastic material is easier to form a concavo-convex pattern than aluminum or glass, which is generally used as a substrate for a magnetic recording medium, but has a low mechanical strength and a thin substrate. This is a problem that is difficult to achieve.
[0012]
The present invention has been made in view of such a problem, and its object is to provide a substrate for an uneven patterned perpendicular magnetic recording medium excellent in flatness, patterning accuracy and mechanical strength, and a method for manufacturing the same, and And a method of manufacturing the perpendicular magnetic recording medium using the substrate.
[0013]
[Means for Solving the Problems]
In order to achieve such an object, the present invention provides a substrate for a perpendicular magnetic recording medium, which has a laminated structure in which at least a support layer and a surface layer are sequentially laminated. The surface layer is made of a thermoplastic resin having a concavo-convex pattern, and the support layer is made of a material having a higher melting point, glass transition point, and mechanical strength than the surface layer.
[0014]
According to a second aspect of the present invention, in the substrate for a perpendicular magnetic recording medium according to the first aspect, the thermoplastic resin is polycarbonate or polymethyl methacrylate.
[0015]
According to a third aspect of the present invention, in the perpendicular magnetic recording medium substrate according to the first or second aspect, the support layer is made of aluminum or glass.
[0016]
Further, the invention according to claim 4 is a method for manufacturing a substrate for a perpendicular magnetic recording medium, comprising the steps of: laminating a surface layer of a thermoplastic resin on a support layer; and heating the surface layer to obtain a desired pattern. Transferring a concave and convex pattern by pressing a stamper on which the pattern is formed.
[0017]
The invention according to claim 5 is a perpendicular magnetic recording medium, wherein a surface layer of a thermoplastic resin having a concavo-convex pattern, and a support layer made of a material having a higher melting point, glass transition point, and mechanical strength than the surface layer. Are laminated, and the underlayer and the magnetic recording layer are sequentially laminated only in the concave portions of the concavo-convex pattern of the surface layer.
[0018]
According to a sixth aspect of the present invention, in the perpendicular magnetic recording medium according to the fifth aspect, the underlayer is a metal having a hexagonal close-packed structure or an alloy thereof, or a metal having a face-centered cubic lattice structure or an alloy thereof. It is characterized by comprising.
[0019]
According to a seventh aspect of the present invention, in the perpendicular magnetic recording medium according to the fifth or sixth aspect, the magnetic recording layer is a CoCrPt-based magnetic recording layer, a granular magnetic recording layer, a RE-TM-based alloy layer, or , Co / Pt or Co / Pd laminated film.
[0020]
Further, according to an eighth aspect of the present invention, in the method for manufacturing a perpendicular magnetic recording medium, the first and second surfaces are provided on the entire surface layer of the substrate for a perpendicular magnetic recording medium according to any one of the first to third aspects. Forming a magnetic layer in order, removing the first and second magnetic layers on the protrusions of the surface layer and removing the underlayer consisting of the first magnetic layer only in the recesses and the second magnetic layer. Forming a magnetic recording layer composed of a layer.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0022]
FIG. 1 is a view for explaining the structure of a substrate for a perpendicular magnetic recording medium according to the present invention. This substrate has a laminated structure of at least two layers, and FIG. 1 shows a support base (support layer). 1 shows an example of a two-layer laminated structure including a surface layer 11 and a surface layer 12.
[0023]
The support base 11 is preferably made of a material having high mechanical strength, for example, aluminum or glass. Further, the surface of the support base 11 is preferably excellent in flatness, and the flatness is generally set to 10 μm or less.
[0024]
The surface layer 12 on which the uneven pattern is formed is made of a thermoplastic resin. Examples of the thermoplastic resin include, for example, polycarbonate (PC) and polymethyl methacrylate (PMMA), as well as polyester and polyolefin materials. Can be used.
[0025]
FIG. 2 is a view for explaining a method for manufacturing a substrate for a perpendicular magnetic recording medium according to the present invention. A surface layer 12 is formed on the entire surface of a support base 11, and the stamper 13 is pressed against the surface layer 12. Is transferred. In addition, as a method of forming the surface layer 12 on the entire surface of the support base 11, for example, a spin coating method or a dipping method can be used, and the uneven shape of the pattern is arbitrarily set by the uneven shape applied to the stamper 13. be able to.
[0026]
FIG. 3 is a diagram for explaining the structure of the perpendicular magnetic recording medium of the present invention. This perpendicular magnetic recording medium has a concave portion of the concave / convex pattern of the perpendicular magnetic recording medium substrate having the structure shown in FIG. The underlayer 14 and the magnetic recording layer 15 are sequentially laminated, and the protective film 16 and the liquid lubrication layer 17 are laminated so as to cover the entire surface of the substrate.
[0027]
As the underlayer 14, for example, a metal having a hexagonal close-packed structure or an alloy thereof, or a metal having a face-centered cubic lattice structure or an alloy thereof is preferable. Such metals having a hexagonal close-packed structure include, for example, Ti, Zr, Ru, Zn, Tc, and Re, and metals having a face-centered cubic lattice structure include, for example, Cu, Rh, Pd, Ag, Ir, Pt, and Au. , Ni, Co and the like. The thickness of the underlayer 14 is preferably thin, but is preferably 3 nm or more for sufficient crystal growth. The underlayer 14 may be formed by laminating a plurality of different materials.
[0028]
Examples of the magnetic recording layer 15 include a generally used CoCrPt-based magnetic recording layer, a granular magnetic recording layer having ferromagnetic crystal grains and a non-magnetic, non-metallic grain boundary surrounding the crystal grains, and a TbCo. Or a laminated film of Co / Pt or Co / Pd. For use as a perpendicular magnetic recording medium, ferromagnetic crystal grains need to have perpendicular anisotropy with respect to the film surface.
[0029]
For example, a thin film mainly composed of carbon is used for the protective film 16, and a perfluoropolyether-based lubricant can be used for the liquid lubricant layer 17, for example.
[0030]
For formation of the underlayer 14, the magnetic recording layer 15, and the protective film 16, a film forming technique such as a vacuum evaporation method, a DC sputtering method, and an RF sputtering method, which is generally used for manufacturing a magnetic recording medium, can be used. The liquid lubricant layer 17 can be formed by, for example, a dipping method or a spin coating method.
[0031]
Hereinafter, Examples and Comparative Examples of the present invention will be described.
(Example and Comparative Example of Substrate for Perpendicular Magnetic Recording Medium)
[Example 1]
A disc-shaped glass disk having an outer diameter of 65 mm, an inner diameter of 20 mm, and a thickness of 0.6 mm was used as a non-magnetic support base, and after washing, a 50 nm PMMA dissolved in hexane was formed on the glass disk by spin coating. To form a surface layer. At this time, the flatness of the glass disk was 1 μm, and the concentration of PMMA was 0.5 wt%.
[0032]
Thereafter, the substrate was introduced into a vacuum pressurizing apparatus, the support base and the stamper were heated until the temperature reached 180 ° C., and the stamper was embossed on the surface layer at a pressure of 12 MPa to transfer the pattern of the stamper. After cooling to 100 ° C. in that state, the surface layer and the stamper were released from the mold and taken out of the vacuum pressurizing device.
[0033]
The stamper used in this embodiment has a cylindrical concavo-convex pattern having a diameter of 100 nm and a height of 50 nm formed by electron beam lithography.
[0034]
[Comparative Example 1]
As a comparative example, a disc-shaped thermoplastic resin disk (substrate) having an outer diameter of 65 mm and an inner diameter of 20 mm was formed by injection molding using the same PMMA as in Example 1 as the thermoplastic resin material. In this injection molding, a mold having a pattern similar to that of the first embodiment is used. In addition, the resin temperature at the time of injection molding was set to 300 ° C., and the thickness of the substrate was changed from 0.6 to 1.2 mm.
[0035]
(Example and Comparative Example of Perpendicular Magnetic Recording Medium)
[Example 2]
A non-magnetic substrate exactly the same as that prepared in Example 1 was used, washed, introduced into a sputtering apparatus, and a NiFeCr layer was formed to a thickness of 15 nm under an Ar gas pressure of 5 mTorr using a Ni15Fe27Cr target. Subsequently, a Ru layer was formed to a thickness of 15 nm under an Ar gas pressure of 30 mTorr using a Ru target to form a NiFeCr / Ru laminated underlayer. Thereafter, using a Co20Cr10Pt target, a CoCrPt magnetic recording layer was formed to a thickness of 25 nm under an Ar gas pressure of 5 mTorr and then taken out of the sputtering apparatus.
[0036]
Next, all the NiFeCr / Ru / CoCrPt layers on the projection were removed by polishing the surface of the surface layer provided on the substrate to the outermost surface of the projection using a diamond slurry. The amount of polishing was monitored with a laser displacement meter, and the point at which the change in the amount of displacement sharply dropped was taken as the end point.
[0037]
After washing, it was introduced into a sputtering apparatus, and a protective layer made of carbon having a thickness of 6 nm was formed under a Ar gas pressure of 8 mTorr using a carbon target, and then taken out of the vacuum apparatus. Thereafter, a 2 nm liquid lubricant layer made of perfluoropolyether was formed by dipping to obtain a patterned perpendicular magnetic recording medium. The formation of the underlayer, the magnetic recording layer, and the protective layer was performed by a DC magnetron sputtering method.
[0038]
[Comparative Example 2]
A patterned perpendicular magnetic recording medium was manufactured under the same conditions as in Example 2 except that the substrate used in Example 2 was exactly the same as that having a thickness of 0.6 mm.
[0039]
[Comparative Example 3]
A patterned perpendicular magnetic recording medium was manufactured under the same conditions as in Example 2 except that the substrate used in Example 2 was exactly the same as that having a thickness of 1.2 mm.
[0040]
[Comparative Example 4]
As a non-magnetic substrate, a chemically strengthened glass substrate (for example, N-5 glass substrate manufactured by HOYA) having a smooth surface is used, washed, introduced into a sputtering apparatus, and a Ni15Fe27Cr target is used under an Ar gas pressure of 5 mTorr. A 15 nm NiFeCr layer was formed. Subsequently, a Ru layer was formed to a thickness of 15 nm under an Ar gas pressure of 30 mTorr using a Ru target to form a NiFeCr / Ru laminated underlayer.
[0041]
Furthermore, a CoCrPt magnetic recording layer was formed to a thickness of 20 nm under an Ar gas pressure of 5 mTorr using a Co20Cr10Pt target, and subsequently a protective layer made of carbon was formed to a thickness of 6 nm under an Ar gas pressure of 8 mTorr using a carbon target. Removed from Thereafter, a 2 nm liquid lubricant layer made of perfluoropolyether was formed by dipping to obtain a perpendicular magnetic recording medium. The formation of the underlayer, the magnetic recording layer, and the protective layer was performed by a DC magnetron sputtering method.
[0042]
Hereinafter, evaluation results of each of these examples and comparative examples will be described.
[0043]
The substrates for perpendicular magnetic recording media obtained in Example 1 and Comparative Example 1 were evaluated for flatness and pattern transfer rate of these substrates. Table 1 shows the results.
[0044]
[Table 1]

[0045]
Here, as for the flatness, the straightness of the displacement of the substrate surface shape in a linear region from 11 mm to 30 mm in the radial direction from the substrate center was obtained by a non-contact optical surface roughness meter. Specifically, for each substrate, four measurements were made at 90 ° intervals in the circumferential direction, and the maximum straightness was defined as the flatness of the substrate surface.
[0046]
Regarding the transfer rate, an error within ± 5% with respect to the design value of the pattern φ100 nm × depth 50 nm was accepted as pass or unacceptable, and the ratio of the passed pattern out of 100 evaluated patterns was taken as the transfer rate. . In addition, AFM (atomic force microscope) was used for this evaluation.
[0047]
The flatness of the substrate for a perpendicular magnetic recording medium of Example 1 was 1 μm, reflecting the flatness of the glass disk used as the supporting base. In the plastic substrate manufactured by injection molding of Comparative Example 1, although the flatness tends to decrease as the plate thickness increases, the perpendicular magnetic recording medium of Example 1 has a flatness of 1.2 mm which is the most excellent in flatness. It is very large compared to the substrate for use.
[0048]
Regarding the transfer rate, in Example 1, a probability of 100% was obtained, while in Comparative Example 1, the thickness remained at 80 to 84% at all plate thicknesses, confirming the superiority of the present invention. .
[0049]
Thus, according to the present invention, it can be seen that a substrate for a perpendicular magnetic recording medium having excellent flatness and excellent pattern transferability can be manufactured. Further, it can be seen that it is possible to reduce the thickness of the thermoplastic resin substrate manufactured by injection molding, which is difficult.
[0050]
In Example 2 and Comparative Examples 2 to 4, the coercive force of the perpendicular magnetic recording medium and the Glide High characteristics (GH characteristics) of the magnetic head were evaluated. Table 2 shows the results.
[0051]
[Table 2]

[0052]
Here, the coercive force was obtained from the MH loop obtained by the VSM. G. FIG. H. The characteristic test is to fly a test head over a rotated medium to detect protrusions, particles, undulations, and the like on the medium surface. The test conditions are a peripheral speed of 7 m / sec, G. H. 12.5 nm was set, and 100 sheets were evaluated for each to obtain a pass rate.
[0053]
First, the evaluation results of the coercive force will be described. It can be seen that the coercive force of the perpendicular magnetic recording medium of Comparative Example 4 in which the magnetic recording layer is a continuous film is as small as 410 Oe, and the interaction between the magnetic grains is very large. By contrast, each of the perpendicular magnetic recording media of Example 2, Comparative Examples 2 and 3, in which the magnetic recording layer is patterned, has a large coercive force. From this, it can be confirmed that the interaction between the magnetic grains of the perpendicular magnetic recording media of Example 2 and Comparative Examples 2 and 3 is small, that is, that the bits are physically separated.
[0054]
However, the coercive force of the perpendicular magnetic recording media of Comparative Examples 2 and 3 is smaller than the coercive force of the perpendicular magnetic recording medium of Example 2. When the perpendicular magnetic recording media of Comparative Examples 2 and 3 are compared, the coercive force of Comparative Example 2 having a smaller substrate thickness is smaller.
[0055]
Considering this result and the fact that the flatness and the pattern transfer rate of Comparative Examples 2 and 3 are low, the accuracy of polishing is lower in Comparative Examples 2 and 3 than in Example 1 because the flatness of the substrate surface is lower. It can be seen that there is a bit that is magnetically connected due to a decrease in the pattern transfer rate, and that the pattern transfer rate is low and there are many variations in the shape.
[0056]
G. FIG. H. According to the evaluation results of the test characteristics, the pass rate of the perpendicular magnetic recording medium of Example 1 was almost the same as that of the perpendicular magnetic recording medium of Comparative Example 4 not subjected to patterning, and was excellent even after a process such as polishing. It can be seen that it shows substrate surface characteristics. On the other hand, as already described, the perpendicular magnetic recording media of Comparative Examples 2 and 3 having low flatness after the production of the substrate hardly pass this test, so that the perpendicular magnetic recording media can be used even after being patterned. It turns out that the result reflects that.
[0057]
【The invention's effect】
As described above, according to the present invention, a surface layer of a thermoplastic resin such as polycarbonate or polymethyl methacrylate is laminated on a support substrate (support layer) such as aluminum or glass, and the surface layer is heated. It is intended to provide a substrate for a perpendicular magnetic recording medium having an uneven pattern on the surface while securing an important smoothness for the substrate because the uneven pattern is transferred by pressing a stamper on which a desired pattern is formed. And the thickness of the substrate can be reduced.
[0058]
In addition, by using the substrate for a perpendicular magnetic recording medium of the present invention, it is possible to provide a patterned perpendicular magnetic recording medium having an excellent surface shape.
[Brief description of the drawings]
FIG. 1 is a view for explaining a configuration of a substrate for a perpendicular magnetic recording medium of the present invention.
FIG. 2 is a diagram illustrating a method of manufacturing a substrate for a perpendicular magnetic recording medium according to the present invention.
FIG. 3 is a diagram for explaining the structure of a perpendicular magnetic recording medium of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Support base 12 Surface layer 13 Stamper 14 Underlayer 15 Magnetic recording layer 16 Protective film 17 Liquid lubrication layer

Claims (8)

Has a laminated structure in which at least the support layer and the surface layer are sequentially laminated,
The surface layer is made of a thermoplastic resin having an uneven pattern formed thereon,
The substrate for a perpendicular magnetic recording medium, wherein the support layer is made of a material having a higher melting point, glass transition point, and mechanical strength than the surface layer. The substrate for a perpendicular magnetic recording medium according to claim 1, wherein the thermoplastic resin is polycarbonate or polymethyl methacrylate. 3. The substrate for a perpendicular magnetic recording medium according to claim 1, wherein the support layer is made of aluminum or glass. Laminating a surface layer of a thermoplastic resin on the support layer,
Transferring the concavo-convex pattern by heating the surface layer and pressing a stamper having a desired pattern formed thereon. A surface layer of a thermoplastic resin having a concavo-convex pattern and a support layer made of a material having a higher melting point, glass transition point, and mechanical strength than the surface layer are laminated,
A perpendicular magnetic recording medium, wherein an underlayer and a magnetic recording layer are sequentially laminated only in the concave portions of the concavo-convex pattern of the surface layer. 6. The perpendicular magnetic recording medium according to claim 5, wherein the underlayer is made of a metal having a hexagonal close-packed structure or an alloy thereof, or a metal having a face-centered cubic lattice structure or an alloy thereof. 6. The magnetic recording layer according to claim 5, wherein the magnetic recording layer is one of a CoCrPt-based magnetic recording layer, a granular magnetic recording layer, a RE-TM-based alloy layer, and a laminated film of Co / Pt or Co / Pd. 7. The perpendicular magnetic recording medium according to item 6. A step of sequentially forming a first and a second magnetic layer on the entire surface of a surface layer provided in the substrate for a perpendicular magnetic recording medium according to claim 1,
The first and second magnetic layers on the convex portions of the surface layer are removed to form an underlayer composed of the first magnetic layer and a magnetic recording layer composed of the second magnetic layer only in the concave portions. And a method for manufacturing a perpendicular magnetic recording medium.

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