JP2016149181A - Magnetic recording medium and magnetic recording/reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording medium which has good flying characteristics of a head, good in-plane uniformity of a pattern, and only small size variations.SOLUTION: A magnetic recording medium includes a base, a magnetic recording layer comprising a plurality of convex magnetic layers and formed on the base, and a protective film formed on the magnetic recording layer. There are gaps in regions surrounded by the protective film, a surface of the base, and corresponding side walls of the magnetic layers.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a magnetic recording medium and a method for manufacturing the same.

  As the amount of information increases significantly, realization of a large-capacity information recording apparatus is eagerly desired. In order to achieve high recording density in hard disk drive (HDD) technology, various technological developments centered on perpendicular magnetic recording have been promoted, and patterned media that can achieve both improved recording density and resistance to thermal fluctuations have been developed. Media has been proposed, and development of its manufacturing technology has become active.

  A patterned medium records one or more magnetic areas as one cell. In order to record 1-bit information in one cell, the recording cells must be magnetically separated from each other. good. Therefore, it is only necessary to form the magnetic dot part and the non-magnetism in the same plane using a microfabrication technique, and by applying a semiconductor manufacturing technique, a fine uneven pattern is formed on the magnetic recording layer provided on the substrate. There is a method of obtaining a magnetically independent pattern by physically dividing the pattern.

  In order to provide the magnetic dot pattern, a mask is formed on the magnetic film in advance and the uneven pattern may be transferred. Alternatively, after providing a concavo-convex pattern on the mask material, the pattern can be selectively deactivated by implanting ions irradiated with high energy into the magnetic region, or the concavo-convex pattern can be formed by pressing the concavo-convex mold on the resist material. There is also a method of transferring.

  A protective film is usually formed on the magnetic film provided with the concavo-convex pattern in order to prevent wear on the surface of the medium accompanying scanning of the magnetic head and corrosion when exposed to the external environment. The protective film must be thin in order to narrow the magnetic spacing for obtaining the magnetic field signal from the magnetic recording layer with high efficiency, but it is also necessary to secure a thickness for preventing the corrosion.

  When forming a protective film against the irregularities of the magnetic recording layer provided on the substrate as described above, if the pattern pitch is sufficiently wide, the protective film uniformly covers the upper and side surfaces of the pattern, so that the flatness is flat. There is no loss of sex. However, in a patterned medium aiming at higher recording density, the interval between the irregularities becomes remarkably narrow, so that the protective film is not uniformly formed, and the position dependency of the irregularities increases. Therefore, the flying stability of the magnetic head is deteriorated, and the signal S / N is inevitably lowered. In the case where a data area in which a pattern for identifying 1 and 0 of a digital signal is arranged and a servo area that carries head positioning information are mixed, the pattern is so dense that the protective film is uniform. Not covered. Therefore, the coverage of the protective film in the narrow pitch uneven pattern is an important item directly linked to improvement of the flying stability of the head and improvement of the signal S / N by reducing the magnetic spacing.

  For example, in a technique for obtaining a magnetic recording uneven pattern by depositing a magnetic film using an uneven pattern provided on a substrate as a base, the pattern after the formation of a protective film has a large unevenness and deteriorates flying stability. Thus, there is a problem that the signal S / N decreases.

  In addition, for example, with the technique of selectively removing the grain boundary portion of the magnetic recording layer formed on the substrate by etching to obtain the magnetic recording uneven pattern, it is difficult to solve the same problem as in Patent Document 1. It was.

JP 2010-192016 A JP 2007-26558 A

  An object of an embodiment of the present invention is to provide a magnetic recording medium having good head flying characteristics and in-plane uniformity of a convex pattern.

According to an embodiment, the substrate,
A magnetic recording layer comprising a plurality of convex magnetic layers formed on the substrate;
A magnetic recording medium comprising: a protective film formed on the magnetic recording layer; and a gap provided in a region surrounded by the protective film, the substrate surface, and a side wall of each magnetic layer. Provided.

It is sectional drawing which represents typically the structure of the magnetic recording medium concerning embodiment. It is a schematic diagram showing the example of the periodic pattern of the magnetic-recording layer used for embodiment. It is a schematic diagram showing the example of the periodic pattern of the magnetic-recording layer used for embodiment. It is a schematic diagram showing the example of the periodic pattern of the magnetic-recording layer used for embodiment. It is a schematic diagram showing the example of the periodic pattern of the magnetic-recording layer used for embodiment. It is a schematic diagram showing the relationship of the dimension of a magnetic layer and a protective layer. It is process drawing of the manufacturing method of the magnetic-recording medium concerning 1st Embodiment. It is process drawing of the manufacturing method of the magnetic-recording medium concerning 2nd Embodiment. It is process drawing of the manufacturing method of the magnetic-recording medium concerning 3rd Embodiment. It is process drawing of the manufacturing method of the magnetic-recording medium concerning 4th Embodiment. It is process drawing of the manufacturing method of the magnetic recording medium concerning 5th Embodiment. It is process drawing of the manufacturing method of the magnetic-recording medium concerning 6th Embodiment. It is a figure showing a nanoimprint stamper preparation process. It is a figure showing the modification of a nanoimprint stamper preparation process. It is a figure for demonstrating another example of the manufacturing method of the magnetic-recording medium based on 1st Embodiment. It is a figure showing an example of the manufacturing method of the magnetic-recording medium by self-organizing lithography. It is a figure showing an example of the manufacturing process of the magnetic-recording medium using a metal microparticle. It is a figure showing another example of the manufacturing process of the magnetic-recording medium using a metal microparticle. It is a figure showing an example of the recording bit pattern with respect to the circumferential direction of a magnetic recording medium. 1 is a partially exploded perspective view of an example of a magnetic recording / reproducing apparatus to which a magnetic recording medium according to an embodiment can be applied. It is a graph showing the relationship between the irradiation angle of the film-forming material at the time of oblique film formation of a protective film, and the film thickness of the formed protective film. It is a graph showing the relationship between the convex part height of a magnetic-recording layer, and a protective layer material density | concentration. Upper surface SEM photograph of one example of magnetic recording medium according to embodiment Sectional TEM photograph of one example of magnetic recording medium according to embodiment

  The magnetic recording medium according to the embodiment includes a substrate, a magnetic recording layer formed on the substrate, which is composed of a plurality of convex magnetic layers, and a protective film formed on the magnetic recording layer. It includes a gap provided in a region surrounded by the substrate surface and the side wall of each magnetic layer.

  A magnetic recording / reproducing apparatus according to an embodiment includes a substrate, a magnetic recording layer formed on the substrate, which includes a plurality of convex magnetic layers, and a protective film formed on the magnetic recording layer. And a recording / reproducing head, and further includes a gap provided in a region surrounded by the protective film, the substrate surface, and the side wall of each magnetic layer.

Furthermore, the manufacturing method of the magnetic recording medium according to the embodiment includes:
Forming a magnetic recording layer on the substrate;
Magnetic recording layer is formed by obliquely depositing a protective film material on the magnetic recording layer by patterning the magnetic recording layer to form a magnetic recording layer composed of a plurality of convex magnetic layers. Forming a protective film on the layer, and providing a void in a region surrounded by the protective film, the substrate surface, and the side wall of each magnetic layer.

  According to the embodiment, the gap is provided in the region surrounded by the protective film, the substrate surface, and the side wall of each magnetic layer, so that the protective film connects the convex magnetic layers, The dent of the protective film provided on the medium is reduced, and the in-plane uniformity on the medium surface is excellent. Thereby, the flying stability at the time of operating the head is improved, and since the air flow generated in the concave portion is small, the head is difficult to drop, and the frequency of head crash due to this can be extremely reduced. In addition, a good signal S / N value can be obtained by levitation stability and reduction of magnetic spacing.

  Here, the oblique film forming means that the film forming material is formed by being incident on the surface of the base material to be formed from an oblique direction. As the film forming technique, for example, a method such as vacuum evaporation, sputtering, or ion beam evaporation can be applied.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing the configuration of the magnetic recording medium according to the embodiment.

  As shown in FIG. 1, a magnetic recording medium 100 according to an embodiment is a magnetic recording medium having a magnetic recording layer 2 having a plurality of convex magnetic layers 26 having a periodic pattern formed on a substrate 1. A magnetic recording layer 2 having magnetism formed on a continuous nonmagnetic layer (not shown) formed on the substrate 1 and having a convex pattern; and a nonmagnetic region having a concave pattern And a magnetic recording layer 2 formed in a convex pattern, and a convex pattern adjacent to the magnetic recording layer 2 and a void 18 provided in a region surrounded by a protective film 9 formed thereon.

  Here, the pattern of the convex magnetic layer 26 constituting the magnetic recording layer 2 is periodic in the surface of the substrate 1. The pattern pitch can be 20 nm or less. When the thickness exceeds 20 nm, the upper and side surfaces of the convex magnetic recording layer are uniformly covered with a protective film, and the flying height of the head tends to deteriorate due to an increase in the unevenness difference.

  In practice, the pattern pitch can be 2 nm or more. When the thickness is less than 2 nm, the pattern separability deteriorates and the transferability of the concavo-convex pattern tends to deteriorate.

  FIGS. 2 to 5 are schematic views showing examples of the periodic pattern of the magnetic recording layer of the magnetic recording medium according to the embodiment.

  The upper surface shape of this periodic pattern is a circle 301 as shown in FIG. 2A, an ellipse 303 as shown in FIG. 3A, a square 305, a rectangle as shown in FIG. It has various structures such as a polygon 307 as shown in a) and is mixed on the substrate regardless of the type and number thereof. The three-dimensional shape is a cylinder 304 as shown in FIG. 2 (b), a cone 306 as shown in FIG. 3 (b), a prism 308 and a pyramid as shown in FIG. 4 (b), and as shown in FIG. 5 (b). Such a structure such as a polygonal column 309 is provided. That is, the value of the taper angle with respect to the substrate surface can be freely set.

  In addition, the pitch of the periodic pattern referred to here indicates a distance from the center of gravity of the pattern of the convex magnetic layer to the center of gravity of the adjacent convex pattern, that is, a state where the pitch is continuous twice or more. This periodic pattern is preferably arranged uniformly in the plane. Even if the pitch is not periodic due to a pattern deficiency or the like, and it is interrupted with a discontinuous value at a certain position, the pitch may be periodic again.

  The thickness of the protective film can have a value lower than the height of the convex pattern of the magnetic recording layer. Further, the protective film concentration distribution in the side wall portion of the convex magnetic recording layer may have an inclination. The protective film concentration distribution can be high on the medium surface side and low on the substrate side. This protective film concentration is the concentration of the main component element of the protective film material with respect to the side surface of the material constituting the magnetic recording layer. The main component element mentioned here means an element containing an amount of 50% or more by atomic weight composition among various elements constituting the protective film material. That is, on the exposed side surface of the convex magnetic recording layer, the surface of the substrate is more adhered to the main component of the protective film material.

  The material of the protective film is selected from various materials, and for example, compounds such as metals, non-metals, alloys, oxides, and nitrides can be used.

  Further, the protective film material is thickest on the convex magnetic recording layer and has a thin structure between the convex and convex portions.

  In the concave pattern portion surrounded by the convex magnetic recording layer and the protective film material, there is a void area where the magnetic recording layer material and the protective film material do not exist. The void region can be composed of an air atmosphere, a vacuum atmosphere, or an inert gas atmosphere.

  A protective film is disposed on the upper portion of the gap region, and connects the convex and convex patterns in a bridge shape. Therefore, since the concave pattern is not exposed on the substrate surface, the vortex of the airflow generated when the head floats is not generated, and the drop of the head with respect to the substrate surface is suppressed, so that the flying stability during head scanning is improved.

  FIG. 6 is a schematic diagram showing the dimensional relationship between the magnetic layer and the protective layer.

  FIG. 6A shows the arrangement of the magnetic layer and the protective layer as viewed from above the magnetic recording medium.

  FIG. 6B is a sectional view taken along the line X-X ′.

  FIG. 6C shows a Y-Y ′ sectional view thereof.

  As shown in FIGS. 6B and 6C, the protective layer 9 has a different thickness depending on the position of the periodic pattern. Specifically, the thickness of the protective layer 9 at the top of the dot is t1 and the thickness of the protective layer 9 between the dots of the magnetic layer 26 is t2 between XX ′ where the pattern is closest, and the pattern is the remotest Y When the protective layer 9 thickness between dots is t3 between −Y ′, the condition is t1 ≦ t2 ≦ t3.

  According to the magnetic recording medium according to the embodiment, the position dependency of the unevenness difference on the surface of the medium can be reduced, the in-plane uniformity is excellent, and the flying characteristics (glide characteristics) of the magnetic head are good, and the magnetic spacing is reduced. A magnetic recording medium having a good signal S / N can be obtained. The magnetic recording medium is capable of reducing the airflow generated in the concave portion, extremely reducing the frequency of head crashes due to the head drop, and achieving both signal S / N due to flying stability.

  In addition, the method of manufacturing a magnetic recording medium according to the embodiment can be divided into, for example, the following seven embodiments.

  FIG. 7A to FIG. 7E are process diagrams of the method for manufacturing the magnetic recording medium according to the first embodiment.

  In the first embodiment, as shown in FIG. 7A, a step of forming a magnetic recording layer 2 on the substrate 1, a step of forming a mask layer 3 on the magnetic recording layer 2, and a step on the mask layer 3 The step of forming the resist layer 19 on the substrate, the step of patterning the resist layer 19 to provide a convex pattern as shown in FIG. 7B, and the step of forming the convex pattern on the mask layer 3 as shown in FIG. As shown in FIG. 7D, the step of transferring from the mask layer 3 to the magnetic recording layer 2, the step of removing the mask layer 3 from the magnetic recording layer 2, and the step of FIG. And forming a magnetic recording medium 101 by obliquely forming a protective film material on the convex pattern of the magnetic recording layer 2 and forming a protective film 9 on the magnetic recording layer 2. . The obtained magnetic recording medium 101 is in a region surrounded by the protective film 9 formed on the magnetic recording layer 2, the protective film 9, the surface of the substrate 1, and the side walls of each magnetic layer of the magnetic recording layer 2. It includes a void 18 provided.

  FIG. 8A to FIG. 8F show process diagrams of a method for manufacturing a magnetic recording medium according to the second embodiment.

  The second embodiment is a modification of the first embodiment. Here, as shown in FIG. 8F, the angle of oblique film formation of the protective film material is changed to an angle different from that in FIG. Magnetic recording is performed in the same manner as in the first embodiment except that a protective film is further deposited on the protective film 9 formed in FIG. 8E and a protective film 9 ′ is formed. A magnetic recording medium 102 having a configuration similar to that of the medium 101 can be formed.

  FIG. 9A to FIG. 9F show process diagrams of a method for manufacturing a magnetic recording medium according to the third embodiment.

  9 (a) through 9 (f) are similar to FIGS. 7 (a) through 7 (f) except that FIG. 9 (e) and FIG. 9 (f) are used instead of FIG. 7 (e). Same as e).

  In the third embodiment, as shown in FIGS. 9 (e) and 9 (f), the thickness of the protective film 9 shown in FIG. After forming the protective film 9b having a thickness, a magnetic recording medium 103 having the same configuration as the magnetic recording medium 101 is formed in the same manner as in the first embodiment except that the film thickness is reduced by etching. be able to.

  FIG. 10A to FIG. 10G are process diagrams of a method for manufacturing a magnetic recording medium according to the fourth embodiment.

  FIGS. 10A to 10G have the same steps as FIGS. 7A to 7E except that FIG. 10F and FIG. 10G are further included.

  In the fourth embodiment, after forming the first protective film 21 by oblique film formation using a protective film material as shown in FIG. 10E, the protective film material as shown in FIG. Except for applying the coating liquid 20 containing, and forming a protective film 9 by further laminating a second protective film 22 on the obliquely formed first protective film 21, the same as in the first embodiment. Thus, the magnetic recording medium 104 having the same configuration as the magnetic recording medium 101 can be formed.

  FIG. 11A to FIG. 11H show process diagrams of a magnetic recording medium manufacturing method according to the fifth embodiment.

  According to the fifth embodiment, as shown in FIG. 11A, the method further includes the step of providing the transfer layer 11 between the mask layer 3 and the resist layer 19, as shown in FIG. The magnetic recording medium 105 can be obtained in the same manner as in the first embodiment except that the method further includes the step of transferring the convex pattern to the transfer layer 11 before the step of transferring the convex pattern to the mask layer. 11B is a step of patterning the resist layer to form a convex pattern, FIG. 11D is a step of transferring the convex pattern to the mask layer, and FIG. 11E is a magnetic recording of the convex pattern. FIG. 11 (f) shows a step of correcting the magnetic recording medium 2 composed of a plurality of convex magnetic layers by removing the mask layer, and FIG. 11 (g) shows an oblique process. In this method, a process of applying a protective film material in an oblique direction is shown, and as a result, a magnetic recording medium 105 having the same configuration as that of the magnetic recording medium 101 can be formed as shown in FIG. .

  FIG. 12A to FIG. 12H show process drawings of a method for manufacturing a magnetic recording medium according to the sixth embodiment.

  In the sixth embodiment, as shown in FIG. 12A, the method further includes a step of providing a release layer 12 between the magnetic recording layer 2 and the mask layer 3, and as shown in FIG. The magnetic recording medium 106 can be obtained in the same manner as in the first embodiment except that the method further includes the step of transferring the convex pattern to the release layer 12 before the step of transferring the pattern to the magnetic recording layer 2. 12B is a step of patterning the resist layer to form a convex pattern, FIG. 12C is a step of transferring the convex pattern to the mask layer, and FIG. 12E is a step of transferring the convex pattern to the magnetic recording layer. FIG. 12F shows the step of forming the magnetic recording medium 2 composed of a plurality of convex magnetic layers by removing the release layer, and FIG. This represents a step of applying the protective film material in the oblique direction in the film formation, and as a result, a magnetic recording medium 106 having the same configuration as the magnetic recording medium 101 can be formed as shown in FIG.

  In the seventh embodiment, as shown in FIGS. 13 to 15, a nanoimprint stamper is produced using a convex pattern provided on a substrate as a template, a convex pattern is provided on the resist layer using the nanoimprint stamper, and the convex pattern is masked. Transfer to the layer to obtain a magnetic recording medium.

  FIG. 13 is a diagram illustrating a nanoimprint stamper manufacturing process.

  First, as shown in FIG. 13A, a resist layer 19 is formed on the substrate 1.

  Next, as shown in FIG. 13B, the resist layer 19 is patterned to obtain a resist layer 19 having a convex pattern.

  Subsequently, as illustrated in FIG. 13C, the conductive film 13 is formed on the convex resist layer 19. In electroforming, which will be described later, if conductive failure occurs, plating growth is hindered and leads to pattern defects. Therefore, the conductive film 13 is preferably formed uniformly on the surface and side surfaces of the convex pattern. However, this is not the case when a conductive material is applied to the metal fine particles and the substrate, and the convex pattern only needs to be electrically conductive. In this case, the conductive film 13 may be formed only on the upper part, the side surface, and the groove part of the metal fine particles.

  The conductive film 13 can be selected from various materials. Examples of the material of the conductive film 13 include Ni, Al, Ti, C, Au, Ag, Cr, and Cu. Here, an example using Ni will be described.

  Subsequently, as shown in FIG. 13 (d), the master master is immersed in a sulfamic acid Ni or NiP bath and energized to perform electroforming, thereby forming an electroformed layer 14 serving as a stamper on the conductive film 13. The film thickness after plating, that is, the thickness of the stamper can be adjusted by changing the current value, plating time, etc., in addition to the hydrogen ion concentration, temperature and viscosity of the plating bath. This electroforming can be performed by electrolytic plating or electroless plating.

  The stamper 201 obtained in this way is released from the substrate 1 as shown in FIG. Finally, unnecessary portions other than the convex pattern surface are mechanically removed and further processed into a desired shape such as a circle or a rectangle, whereby the stamper can be completed.

  FIG. 14A to FIG. 14I are diagrams showing modifications of the nanoimprint stamper manufacturing process.

  As shown in FIG. 14A, a mask layer 3, a transfer layer 11, and a resist layer 19 are formed on the substrate 1.

  Next, as shown in FIG. 14B, the resist layer 19 is patterned to obtain a resist layer 19 having a convex pattern.

  Subsequently, as shown in FIG. 14C, the convex pattern is transferred to the transfer layer 11.

  Thereafter, the convex pattern is transferred to the mask layer 3 as shown in FIG.

  Further, as shown in FIG. 14E, the convex pattern is transferred to the substrate 1.

  Then, as shown in FIG.14 (f), a mask layer is peeled and the board | substrate 1 with which the convex-shaped pattern was formed is obtained.

  Subsequently, as shown in FIG. 14G, a conductive film 13 is formed on the substrate 1.

  Subsequently, as shown in FIG. 14 (h), the master master is immersed in a sulfamic acid Ni or NiP bath and energized to perform electroforming to form an electroformed layer 14 serving as a stamper on the conductive film 13.

  The stamper 202 obtained in this way is released from the substrate 1 as shown in FIG.

  Further, after the step of FIG. 14 (g), it is possible to transfer a convex pattern to the substrate 1 through the mask layer 3, and to produce a stamper using a master master having the convex pattern transferred to a substrate (not shown). It is.

  A replica stamper can be produced by replacing the stamper as a master master. In this case, a method of obtaining a Ni stamper from a Ni stamper, a method of obtaining a resin stamper from a Ni stamper, and the like can be mentioned.

  FIGS. 15A to 15J are views for explaining yet another example of the method for manufacturing the magnetic recording medium according to the first embodiment.

  As shown in FIG. 15A, these resist materials are applied onto a sample having a magnetic recording layer 2 and a mask layer 3 on a substrate 1 to form a resist layer 15. Next, as shown in FIG. 15B, a resin stamper 202 having a convex pattern is imprinted on the resist layer 15. At the time of imprinting, when the resin stamper 202 is pressed by the resist, the resist is fluidized and a convex pattern is formed. Here, by applying energy such as ultraviolet rays to the resist layer 15, the resist layer 15 forming the convex pattern is cured, and then the resin stamper 202 is released to obtain the convex pattern of the resist layer 15. It is done. In order to easily release the resin stamper 202, the surface of the resin stamper 202 may be previously subjected to release treatment with a silane coupling agent or the like.

Next, as shown in FIG. 15C, the resin stamper 202 having pressed the imprint resist is released. Here, since the resist material remains as a residue in the concave portion of the resist layer 15 after the mold release of the resin stamper 202, the mask layer 3 is removed by etching as shown in FIG. Expose the surface. Since polymer-based resist materials generally have low etching resistance against O ₂ etchants, residues can be easily removed by dry etching using O ₂ gas. When an inorganic material is included, the etching gas can be changed as appropriate so that the resist pattern remains. Thereafter, the convex pattern is transferred to the mask layer 3 and the magnetic recording layer 2 as shown in FIGS. 15 (d), (f), (g), and (h).

  Thereafter, as shown in FIG. 15 (i), a protective film material is obliquely formed on the convex pattern of the magnetic recording layer 2, and a protective film 9 is formed on the magnetic recording layer 2, thereby forming the protective film 9 in FIG. As shown in j), the magnetic recording medium 107 is formed. The obtained magnetic recording medium 107 is in a region surrounded by the protective film 9 formed on the magnetic recording layer 2, the protective film 9, the surface of the substrate 1, and the side walls of each magnetic layer of the magnetic recording layer 2. It includes a void 18 provided.

  In this way, the magnetic recording medium 107 having a convex pattern can be manufactured by nanoimprinting.

  In the first to seventh embodiments, as a method of providing a convex pattern on the resist layer, as shown in FIGS. 16 to 18, for example, lithography using energy rays, nanoimprint, block copolymer having at least two kinds of polymer chains And a patterning method using a metal fine particle as a mask. When a self-assembled film is used, a convex pattern can be transferred by forming a microphase separation structure in the film and then selectively removing one polymer phase and using the remaining polymer phase as a mask. it can. Moreover, when using a metal fine particle mask, a convex pattern can be transcribe | transferred by using the metal fine particle distribute | arranged on the same plane as an independent mask layer. Further, using the convex pattern as a convex template, a nanoimprint stamper may be produced from the template, and the convex pattern may be transferred using the nanoimprint stamper.

  FIG. 16 is a diagram showing an example of a method for manufacturing a magnetic recording medium by self-organized lithography.

  First, as shown in FIG. 16A, a magnetic recording medium in which a magnetic recording layer 2 and a mask layer 3 are formed on a substrate 1 is prepared.

  In the case of using a self-assembled film, the magnetic recording layer 2, the mask layer 3, and the resist layer 19 are formed on the substrate 1 as shown in FIG. 7A, and as shown in FIG. Instead of transferring the convex pattern by photolithography, a self-assembled layer 24 made of a block copolymer having two or more types of polymer chains shown in FIG. 16B is formed on the mask layer 3 shown in FIG. As shown in FIG. 16C, the microphase separation structures 25 and 26 are formed in the self-assembled layer 24 by, for example, thermal annealing, and then, as shown in FIG. The seed polymer phase 25 is selectively removed, and the remaining polymer 26 is used as a mask to transfer the convex pattern. Subsequently, as shown in FIG. 16 (e), the step of transferring the convex pattern to the mask layer 3, as shown in FIG. 16 (f), the step of transferring the convex pattern to the magnetic recording layer 2, and the mask layer 3 A step of peeling and obtaining a patterned magnetic recording medium as shown in FIG.

  Further, as shown in FIG. 16H, a protective film material is obliquely formed on the convex pattern of the magnetic recording layer 2, and a protective film 9 is formed on the magnetic recording layer 2, thereby forming the protective film 9 in FIG. As shown in i), the magnetic recording medium 108 is formed. The obtained magnetic recording medium 108 is in a region surrounded by the protective film 9 formed on the magnetic recording layer 2, the protective film 9, the surface of the substrate 1, and the side wall of each magnetic layer of the magnetic recording layer 2. It includes a void 18 provided.

  FIGS. 17A to 17H show an example of a manufacturing process of a magnetic recording medium using metal fine particles.

  First, as shown in FIG. 17A, a mask layer 3 is formed on a magnetic recording medium 2 provided on a substrate 1.

  Next, as shown in FIG. 17B, a metal fine particle coating solution 6 containing the metal fine particles 4 and the first solvent 5 is dropped and applied to the mask layer 3, and as shown in FIG. A metal fine particle film 8 in which a plurality of metal fine particles 4 are arranged is obtained on the mask layer 3.

  Subsequently, as shown in FIG. 17D, the convex pattern constituted by the metal fine particle film 8 is transferred to the mask layer 3.

  Next, as shown in FIG. 17E, the convex pattern is transferred to the magnetic recording layer 2 through the metal fine particle film 8 and the patterned mask layer 3.

  Subsequently, as shown in FIG. 17 (f), the mask layer 3 and the single-layer metal fine particle film 8 on the magnetic recording layer 2 are removed, whereby the patterned magnetic recording provided on the substrate 1 is provided. Layer 2 is obtained.

  Thereafter, as shown in FIG. 17G, a protective film material is obliquely formed on the convex pattern of the magnetic recording layer 2 to form a protective film 9 on the magnetic recording layer 2, thereby forming the protective film 9 in FIG. As shown in j), the magnetic recording medium 109 is formed. The obtained magnetic recording medium 109 is in a region surrounded by the protective film 9 formed on the magnetic recording layer 2, the protective film 9, the surface of the substrate 1, and the side walls of each magnetic layer of the magnetic recording layer 2. It includes a void 18 provided.

  FIG. 18 is a diagram showing another example of the manufacturing process of the magnetic recording medium using metal fine particles.

  First, a magnetic recording medium having a magnetic recording layer formed on a substrate is prepared.

  As shown in FIG. 18A, a mask layer 3 is formed on a magnetic recording medium 2 provided on a substrate 1.

  Next, as shown in FIG. 18 (b), a metal fine particle coating solution 6 containing metal fine particles 4 and a solvent 5 covered with a protective material (not shown) is dropped and applied to the mask layer 3, and FIG. 18 (c) is applied. As shown, a metal fine particle film 8 in which a plurality of metal fine particles are regularly arranged is obtained.

  Subsequently, as shown in FIG. 18D, an overcoat layer 16 covering the surface of the metal fine particle film 8 and the surface of the mask layer 3 on which the metal fine particle film 8 is formed is formed.

  Thereafter, as shown in FIG. 18 (e), the protective material on the surface of the metal fine particles 4 is deactivated by irradiating the metal fine particle film 8 with energy rays through the overcoat layer 16.

  Further, as shown in FIG. 18 (f), the overcoat layer 16 is etched using the metal fine particle layer 8 as a mask to form a convex pattern made of the metal fine particle film 8 on the surface of the mask layer 3.

  Subsequently, as shown in FIG. 18G, the convex pattern constituted by the single-layer metal fine-particle film 8 is transferred to the mask layer 3.

  Next, as shown in FIG. 18H, the convex pattern is transferred to the magnetic recording layer 2 through the single-layer metal fine particle film 8 and the patterned mask layer 3.

  Subsequently, as shown in FIG. 18 (i), by removing the mask layer 3 and the single-layer metal fine particle film 8 on the magnetic recording layer 2, the substrate 1 and the patterned magnetic layer provided thereon are obtained. Recording layer 2 is obtained.

  Further, as shown in FIG. 18 (j), a protective film material is obliquely formed on the convex pattern of the magnetic recording layer 2, and a protective film 9 is formed on the magnetic recording layer 2, thereby forming a protective film 9 in FIG. As shown in k), the magnetic recording medium 110 is formed. The obtained magnetic recording medium 110 is in a region surrounded by the protective film 9 formed on the magnetic recording layer 2, the protective film 9, the surface of the substrate 1, and the side wall of each magnetic layer of the magnetic recording layer 2. It includes a void 18 provided.

  In forming the protective film, the protective film is formed on the magnetic recording layer by irradiating the protective film material obliquely with respect to the substrate surface. At this time, the angle at which the protective film material is used for oblique film formation may be appropriately changed during the formation of the protective film, and the protective film can be formed by setting a plurality of irradiation angles.

  Here, the irradiation angle refers to an angle measured when the vertical direction with respect to the substrate surface is 0 ° and the horizontal direction is 90 °. That is, the case where the substrate surface and the protective layer material face each other is 0 °, and the case where the substrate uneven surface faces the protective layer material is 90 °.

  When the protective film material is formed obliquely, the sample jig is inclined with respect to the fixed protective film material source, the sample substrate loaded on the jig is inclined, or fixed. There is a method such as disposing the protective film material source at an angle with respect to the substrate material.

  The protective film material can be selected from various materials, but a nonmagnetic material is preferably used. For example, it can be selected from Al, Si, Ti, V, Cr, Mn, Cu, Zn, Ge, Y, Zr, Mo, Pd, Ag, xHf, W, Pt, Au, and the like.

  The thickness of the protective film material is preferably 5 nm or less in order to improve the signal S / N by reducing the magnetic spacing. Moreover, in order to make the coverage with respect to a convex pattern favorable, it is desirable to make it thicker than 0.1 nm.

The void area surrounded by the magnetic recording layer and the protective film can be replaced with the atmosphere during the formation of the protective film. For example, when the protective film is formed in an inert gas atmosphere such as He, N ₂ , and Ar, the void is filled with the inert gas.

  In the second embodiment, the irradiation angles for forming the protective film material obliquely may be set as appropriate, such as θ1, θ2, θ3,... Θn (n is an integer).

  In the third embodiment, after forming a thick film by forming the protective film material obliquely, the film thickness can be reduced by wet etching or dry etching, and the surface roughness can be reduced. Further, in combination with the second embodiment, the protective film thickness reduction process by etching may be repeated after oblique film formation at different irradiation angles.

  In the fourth embodiment, a surface roughness can be reduced by applying a solution containing a protective film material to the surface of the protective film material formed by oblique incidence. The protective film material is applied by various methods. For example, a spin coating method, a dip coating method, a spin casting method, a Langmuir Blodget method, an ink jet method, or the like can be applied.

  In the fifth embodiment, the transfer layer provided on the mask layer is made of various materials. In addition, methods such as wet etching and dry etching can be applied during the processing. By using the transfer layer, the transfer accuracy of the convex pattern can be improved.

  In the sixth embodiment, the release layer provided on the magnetic recording layer can be composed of various materials such as metals, alloys, compounds, and organic substances. After transferring the convex pattern to the magnetic recording layer, the mask layer and the particles existing on the mask layer can be removed from the medium surface by dissolving the release layer. Therefore, the surface of the medium can be cleaned and the surface properties can be improved.

  In the seventh embodiment, an imprint stamper is produced from a convex pattern of a resist layer provided on a substrate, and the convex pattern is transferred to the magnetic recording layer by nanoimprint lithography using the imprint stamper. By applying nanoimprinting, a pattern can be collectively transferred over a large area of the substrate, and manufacturing throughput can be improved.

Note that the first to seventh embodiments of the manufacturing method according to the above may be combined with each other.

  According to the method for manufacturing a magnetic recording medium according to the above-described embodiment, the difference in unevenness on the magnetic recording medium is reduced, the flying characteristics of the head are good, and the signal S / N is excellent due to the reduction in magnetic spacing. Media can be manufactured. Further, it is possible to easily form a protective film on the surface of the medium with good head flying characteristics, thereby simplifying the manufacturing process.

Magnetic recording layer forming step First, a magnetic recording layer is formed on a substrate to obtain a magnetic recording medium.

  Although there is no limitation on the shape of the substrate, it is usually circular and hard. For example, a glass substrate, a metal-containing substrate, a carbon substrate, a ceramic substrate, or the like is used. In order to improve the in-plane uniformity of the pattern, it is desirable to make the convex pattern on the substrate surface small. In addition, a protective film such as an oxide film can be formed on the substrate surface as necessary.

  As the glass substrate, amorphous glass typified by soda lime glass or aluminosilicate glass, or crystallized glass typified by lithium glass can be used. In addition, a sintered body substrate mainly composed of alumina, aluminum nitride, or silicon nitride can be used as the ceramic substrate.

  A magnetic recording layer having a perpendicular magnetic recording layer mainly composed of cobalt is formed on the substrate.

  Here, a soft magnetic under layer (SUL) having a high magnetic permeability can be formed between the substrate and the perpendicular magnetic recording layer. The soft magnetic underlayer bears a part of the magnetic head function of circulating the recording magnetic field from the magnetic head for magnetizing the perpendicular magnetic recording layer, and applies a steep and sufficient perpendicular magnetic field to the recording layer of the magnetic field, Recording / reproduction efficiency can be improved.

  For the soft underlayer, for example, a material containing Fe, Ni, Co can be used. Of these materials, amorphous materials exhibiting excellent soft magnetism without crystal magnetic anisotropy, crystal defects and grain boundaries can be preferably used. By using a soft magnetic amorphous material, the noise of the recording medium can be reduced. As the soft magnetic amorphous material, for example, a Co alloy containing Co as a main component and containing at least one of Zr, Nb, Hf, Ti, and Ta, such as CoZr, CoZrNb, and CoZrTa can be selected.

  In addition, an underlayer can be provided between the soft magnetic backing layer and the substrate in order to improve the adhesion of the soft magnetic backing layer. As the underlayer material, Ni, Ti, Ta, W, Cr, Pt, an alloy thereof, an oxide thereof, a nitride thereof, or the like can be used. For example, NiTa, NiCr, or the like can be used. These layers may be composed of a plurality.

  Furthermore, an intermediate layer made of a nonmagnetic metal material can be provided between the soft magnetic underlayer and the perpendicular magnetic recording layer. The role of the intermediate layer is to block the exchange coupling interaction between the soft magnetic underlayer and the perpendicular magnetic recording layer and to control the crystallinity of the perpendicular magnetic recording layer. The intermediate layer material can be selected from Ru, Pt, Pd, W, Ti, Ta, Cr, Si, or alloys thereof, oxides thereof, and nitrides thereof.

The perpendicular magnetic recording layer can contain Co as a main component, at least Pt, and further contain a metal oxide. In addition to Co and Pt, one or more elements selected from B, Ta, Mo, Cu, Nd, W, Nb, Sm, Tb, and Ru can be included. By containing the above elements, it is possible to promote the micronization of the magnetic particles and improve the crystallinity and orientation, thereby obtaining recording / reproducing characteristics and thermal fluctuation characteristics suitable for high recording density. . Specifically, an alloy such as a CoPt alloy, a CoCr alloy, a CoCrPt alloy, CoPtO, CoPtCrO, CoPtSi, CoPtCrSi, or CoCrSiO ₂ can be used for the perpendicular magnetic recording layer.

  The thickness of the perpendicular magnetic recording layer is preferably 1.0 nm or more in order to measure the reproduction output signal with high accuracy, and 40 nm or less in order to suppress distortion of the signal intensity. If it is thinner than 1.0 nm, the reproduction output is extremely small and the noise component tends to be dominant. Conversely, if it is thicker than 40 nm, the reproduction output becomes excessive and the signal waveform tends to be distorted.

A protective layer can be provided on the perpendicular magnetic recording layer. The protective layer has the effects of preventing corrosion and deterioration of the perpendicular magnetic recording layer and preventing damage to the medium surface that occurs when the magnetic head comes into contact with the recording medium. Examples of the protective layer material include those containing C, Pd, SiO ₂ , and ZrO ₂ . Carbon can be classified into sp ² bonded carbon (graphite) and sp ³ bonded carbon (diamond). Durability and corrosion resistance are superior to sp ³ bonded carbon, and conversely flatness is superior to sp ² bonded carbon. Usually, the deposition of carbon is performed by sputtering using a graphite target, although amorphous carbon sp ² -bonded carbon and sp ³ -bonded carbon are mixed is deposited, in which the ratio of sp ³ -bonded carbon is larger diamond It is called like carbon (DLC) and is excellent in durability, corrosion resistance and flatness, and is more suitable as a protective layer for a magnetic recording layer.

  A lubricating layer can be further provided on the protective layer. Examples of the lubricant used in the lubricating layer include perfluoropolyether, fluorinated alcohol, and fluorinated carboxylic acid. Thus, a perpendicular magnetic recording medium is formed on the substrate.

Mask layer forming step A mask layer for transferring a convex pattern is formed on the magnetic recording layer.

  When a protective layer is provided on the magnetic recording layer, the mask layer can be provided on the protective layer.

  Since this mask layer serves as a main mask in the processing of the magnetic recording layer, it is preferable to use a material that can maintain an etching selectivity with respect to the magnetic recording layer and the metal fine particle material described later. Specific materials include, for example, Al, C, Si, Ti, V, Cr, Mn, Co, Ni, Cu, Fe, Zn, Ga, Zr, Nb, Mo, Ru, Pd, Ag, Au, and Hf. It is also possible to apply to the mask layer a material selected from the group consisting of Ta, W, and Pt and consisting of these compounds or alloys. Here, the compound is selected from oxides, nitrides, borides, carbides, and the like, and the alloy is composed of two or more materials selected from the above group. In this case, it is possible to select a mask layer material that can ensure an etching selectivity with respect to the material of the metal fine particle film formed on the mask layer and the convex pattern dimension, and to determine the film thickness appropriately. .

  These mask layers are formed by physical vapor deposition (PVD: Physical Vapor Deposition) represented by vacuum deposition, electron beam deposition, molecular beam deposition, ion beam deposition, ion plating, and sputtering. In addition, it can be formed by chemical vapor deposition (CVD) using heat, light, or plasma.

  The thickness of the mask layer can be changed by appropriately changing parameters such as process gas pressure, gas flow rate, substrate temperature, input power, ultimate vacuum, chamber atmosphere, and film formation time in physical and chemical vapor deposition. Adjustment is possible. The alignment accuracy of the metal fine particle layer formed on the mask layer and the transfer accuracy of the convex pattern strongly depend on the surface roughness of the mask layer. Therefore, it is preferable to reduce the surface roughness of the mask layer, and this can be realized by variously adjusting the film forming conditions. In order to pattern a narrow pitch pattern with high definition, it is particularly preferable that the period of the surface roughness is small with respect to a desired pattern pitch. The average surface roughness value is preferably 0.6 nm or less. If it is larger than 0.6 nm, the alignment accuracy of metal fine particles, which will be described later, deteriorates and the signal S / N of the magnetic recording medium tends to deteriorate.

  In order to reduce the surface roughness, this can be realized by changing the film forming conditions variously and changing the mask layer material from crystalline to amorphous.

The thickness of the mask layer can be determined in consideration of the etching selectivity with respect to the release layer and the magnetic recording layer and the convex pattern dimension. The mask layer can be formed by adjusting parameters such as process gas pressure, gas flow rate, substrate temperature, input power, ultimate vacuum, chamber atmosphere, and film formation time. The sputtering gas used in the film formation can be mainly a rare gas such as Ar, and a desired alloy can be obtained by mixing a reactive gas such as O ₂ or N _{2 with} a mask material to be formed. A film can also be formed.

  The thickness of the mask layer is preferably 1 nm or more and 50 nm or less in order to transfer a fine pattern with high definition. If it is thinner than 1 nm, the mask layer is not uniformly formed, and if it is thicker than 50 nm, the transfer accuracy of the convex pattern in the depth direction tends to deteriorate.

  As will be described later, after forming the convex pattern on the magnetic recording layer via the mask layer, the magnetic recording layer having the convex pattern can be obtained by removing the mask layer. Here, when removing the mask layer, a method such as dry etching or wet etching is applied. However, a peeling layer is formed between the mask layer and the magnetic recording layer in advance, and the magnetic recording is performed by removing this. The mask layer can also be peeled from the layer. In the case where a protective layer is provided on the magnetic recording layer, the release layer can be provided on the protective layer.

  The release layer is peeled off by dry etching and wet etching, and finally plays a role of removing the mask material from the magnetic recording layer.

  The release layer can be selected from various inorganic materials and polymer materials, and an etching solution capable of dissolving them can be appropriately selected.

As the inorganic materials usable in the peeling layer, for example, C, Mo, W, Zn , Co, Ge, Al, Cu, Au, Ag, Ni, Si, metals such as SiO ₂ and Cr, compounds, and two or more An alloy made of any of these metals can be used. These inorganic materials can be peeled off by dry etching using an etching gas such as O ₂ , CF ₄ , Cl ₂ , H ₂ , N ₂ , and Ar.

  For each material, acid such as hydrochloric acid, phosphoric acid, nitric acid, boric acid, acetic acid, hydrofluoric acid, ammonium fluoride, perchloric acid, hydrobromic acid, carboxylic acid, sulfonic acid, hydrogen peroxide water, etc. Or aqueous sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, magnesium hydroxide, ammonium hydroxide, tetramethylammonium hydroxide, tetrapropylammonium hydroxide, phenyltrimethylammonium hydroxide, etc. An alkaline solution can be applied.

Moreover, you may add suitably the buffer solution for adjusting the pH of a solution.

  A polymer material can also be applied to the release layer. Examples thereof include novolak resins represented by general-purpose resist materials, polystyrene, polymethyl methacrylate, methyl styrene, polyethylene terephthalate, polyhydroxy styrene, polyvinyl pyrrolidone, and polymethyl cellulose. These resist materials can be removed using an organic solvent or water. In addition, in order to improve etching resistance, it is also possible to use a composite material containing a polymer material and a metal.

  When the release layer is dissolved by wet etching using the above acid, alkali, or organic solvent, it is desirable that the dissolution rate with respect to the magnetic recording layer and the substrate is sufficiently lower than the dissolution rate of the release layer.

  One or two or more mask layers can be formed. The magnetic recording layer and the mask layer on the release layer as described above may be a laminate including, for example, a first mask layer and a second mask layer. For example, by configuring the first mask layer and the second mask layer from different materials, it is possible to increase the etching selectivity and improve the transfer accuracy. Here, for convenience, the second mask layer is referred to as a transfer layer for the first mask layer, and is expressed as magnetic recording layer / mask layer / transfer layer from the substrate side.

This transfer layer can be appropriately selected from various materials in consideration of the etching selectivity with the metal fine particle material and the mask layer material. When determining a combination of mask materials, a metal material corresponding to an etching solution or an etching gas can be selected. When combining the materials assuming dry etching, for example, C / Si, Si / Al, Si / Ni, Si / Cu, Si / Mo, Si / MoSi ₂ , Si in the order of the mask layer / transfer layer from the substrate side In addition to / Ta, Si / Cr, Si / W, Si / Ti, Si / Ru, Si / Hf, etc., Si can be replaced with SiO ₂ , Si ₃ N ₄ , SiC, or the like. Al / Ni, Al / Ti, Al / TiO ₂ , Al / TiN, Cr / Al ₂ O ₃ , Cr / Ni, Cr / MoSi ₂ , Cr / W, GaN / Ni, GaN / NiTa, GaN / NiV , Ta / Ni, Ta / Cu, Ta / Al, Ta / Cr, etc. can be selected. Note that the stacking order of these various mask materials may be changed depending on the etching gas used in the mask processing.

  The combination and stacking order of the mask materials are not limited to those described above, and can be appropriately selected from the viewpoints of pattern dimensions and etching selectivity. In addition, patterning by wet etching as well as dry etching is possible, so that each mask material can be selected in consideration of this.

  When patterning the mask layer by wet etching, side etching in the width direction of the convex pattern is suppressed. This case can be realized by setting various parameters including the composition of the mask material, the concentration of the etching solution, and the etching time.

Next, a resist layer for forming a convex pattern is formed on the mask layer.

  In order to form a fine convex pattern on the resist layer, for example, a resist for ultraviolet / electron beam exposure typified by a novolac resin, a nanoimprint resist having a curing action by heat or ultraviolet irradiation, a polymer self-assembled film It is possible to apply metal fine particles and the like.

  The resist layer used for exposure or nanoimprinting can be formed by applying a precursor solution of a resist material. In this case, the thickness of the resist layer can be determined in consideration of the pattern pitch and the etching selectivity to the underlying mask layer.

  Application of the solution can be performed on the substrate by various methods such as spin coating, spray coating, spin casting, dip coating, and ink jet. Since the resist layer immediately after coating contains a large amount of solvent, pre-baking can be performed to lower the fluidity of the resist material. When the adhesion of the resist layer to the mask layer is poor, the mask layer surface can be pretreated. Specific examples include baking for removing moisture from the mask layer and hydrophobic treatment by application of a hexamethyldisilazane solution.

  The resist layer is not a single layer, and a resist layer having a different exposure sensitivity can have a multilayer structure, for example, in accordance with the transfer process.

  There is no limitation on the type of resist material, and various resist materials such as a main chain cutting type, a chemical amplification type, and a crosslinking type can be used.

  It is also possible to form a self-assembled layer for forming a convex pattern on the mask layer and transfer it to the convex pattern. The self-assembled film is typified by a diblock copolymer having at least two different polymer chains, and the basic structure of the self-assembled film is covalently bonded to the ends of polymers having different chemical properties such as (Block A)-(Block B). It is what you are doing. The self-assembled film is not limited to a diblock copolymer, and other triblock copolymers and random copolymers may be used depending on the combination of materials.

  Examples of the material that forms the polymer block include polyethylene, polystyrene, polyisoprene, polybutadiene, polypropylene, polydimethylsiloxane, polyvinylpyridine, polymethyl methacrylate, polybutyl acrylate, polybutyl methacrylate, polydimethylacrylamide, polyethylene oxide, and polypropylene oxide. , Polyacrylic acid, polyethylacrylic acid, polypropylacrylic acid, polymethacrylic acid, polylactide, polyvinyl carbazole, polyethylene glycol, polycaprolactone, polyvinylidene fluoride, and polyacrylamide. A block copolymer can be constituted by using the following polymer.

  A self-assembled film using a block copolymer can be formed on the mask layer by a spin coating method or the like. In this case, a solvent in which the polymers constituting each phase are compatible with each other can be selected, and a solution in which the solvent is dissolved can be used as the coating solution.

  Specific solvents include, for example, toluene, xylene, hexane, heptane, octane, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, ethylene glycol trimethyl ether, ethyl lactate, Examples include ethyl pyruvate, cyclohexanone, dimethylformamide, dimethylacetamide, tetrahydrofuran, anisole, and diethylene glycol triethyl ether.

  The film thickness of the self-assembled film can be changed using the concentration of the coating liquid when these solvents are used and various parameters set during film formation.

  In the self-assembled film, polymers such as heat are phase-separated by applying energy such as heat, and a microphase-separated structure is formed inside the film. The microphase-separated structure exhibits different aspects depending on the molecular weight of the polymer constituting the self-assembled film. For example, in the case of a diblock copolymer, an island-like dot or cylinder structure of polymer B is formed in the sea-like (matrix) pattern of polymer A. In addition, a lamella structure in which the polymers A and B are laminated on the same plane or a sphere structure in which the sea-island pattern is reversed can be formed. By selectively removing one polymer phase in this pattern, a convex pattern of the self-assembled film can be formed.

  Energy is applied from the outside when the microphase separation structure of the self-assembled film is formed. The energy can be applied by annealing using heat, or so-called solvent annealing in which a sample is exposed to a solvent atmosphere. When performing thermal annealing, a temperature that does not deteriorate the alignment accuracy of the self-assembled film is set.

  Note that the upper portion of the mask layer may be chemically modified in order to improve the alignment accuracy of the self-assembled pattern. Specifically, the arrangement of the block copolymer can be improved by modifying one of the polymer phases constituting the block copolymer on the mask surface. In this case, surface modification at the molecular level can be performed by polymer application, annealing, and rinsing. By applying the above-mentioned block copolymer solution on this, it is possible to obtain a pattern with good in-plane uniformity.

  In addition, metal fine particles having a desired pattern pitch can be used as a mask. When metal fine particles are used as a mask layer, since the fine particles themselves correspond to the convex portions of the mask layer, the pattern can be transferred to the lower portion as long as this can be maintained. By using the metal fine particle material, it is possible to perform patterning for a large area, and the process time can be greatly reduced as compared with conventional convex pattern forming methods such as electron beam exposure. Moreover, it is possible to perform patterning on a large area at low cost by applying to the nanoimprint method described later.

  When metal fine particles are used as the convex pattern mask, it is preferable that the metal fine particles are arranged in a single layer over a wide area on the substrate, which can reduce the signal intensity positional variation in the magnetic recording medium, and abnormalities after pattern transfer Good glide characteristics can be obtained as the protrusions are reduced.

  As the metal fine particle mask, a single layer array on the substrate is used.

  When the metal fine particles to be the convex pattern mask are arranged on the substrate, a coating solution in which the metal fine particles are dispersed in a solvent, that is, a so-called dispersion liquid is used. Hereinafter, it is referred to as a coating solution. In this coating solution, at least one type of metal fine particles are monodispersed while maintaining a certain distance from each other. The term “monodispersed” as used herein means a state in which metal fine particles exist independently in a solution without agglomeration and fusion.

  In order for the metal fine particles to be stably dispersed in the solvent, the surface of the metal fine particles is preferably coated with a protective material. The definition of this protective material is that it contains a surfactant and covers the surface of the metal fine particles. Furthermore, it is desirable that the affinity for the metal fine particle material is high.

  This protective material is preferably applied before the metal fine particles refined by various methods are dispersed in the dispersion medium, but depending on the production method, the fine particles are re-dispersed by adding to the dispersion medium. It doesn't matter how.

  This protective material plays the role which suppresses aggregation of metal microparticles by the physical effect | action accompanying the steric hindrance of a polymer chain other than the chemical effect | action which reduces van der Waals attraction between metal microparticles.

  Specific examples of the protective material include thiol groups, amino groups, ketone groups, carboxyl groups, ether groups, and hydroxyl groups. Specifically, alkanethiol, dodecanethiol, polyvinylpyrrolidone, oleylamine, and the like are preferable. In addition, polymer materials such as sodium polycarboxylate and ammonium polycarboxylate can be used.

  The metal fine particle material is at least one selected from the group consisting of C, Pt, Ni, Pd, Co, Al, Ti, Ce, Si, Fe, Au, Ag, Cu, Ta, Zr, Zn, Mo, W, and Ru. A material composed of an alloy, a mixture, or an oxide composed of two or more selected from the above group can be used.

  Further, it is desirable to use a metal fine particle having an average particle diameter of 2 nm to 50 nm. This is because fine particles smaller than 2 nm are more difficult to produce, and when larger than 50 nm, the fine particle mask having a multilayer structure is insufficiently peeled and flatness is impaired.

The solvent in which the metal fine particles are dispersed can be selected from various organic solvents. Specifically, for example, toluene, xylene, hexane, heptane, octane, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, ethylene glycol trimethyl ether, ethyl lactate, pyruvic acid Examples include ethyl, tetradecane, cyclohexanone, dimethylformamide, dimethylacetamide, tetrahydrofuran, anisole, and diethylene glycol triethyl ether, ethanol, methanol, isopropanol, water, and the like.

  A metal fine particle coating solution is obtained by mixing the metal fine particles and the solvent as described above. In addition, when aggregation of microparticles | fine-particles arises, it is possible to re-disperse metal microparticles by using methods, such as ultrasonic dispersion, after mixing.

  Moreover, you may add the dispersing agent for promoting the monodispersion of a metal microparticle with respect to a metal microparticle coating liquid. The dispersant can be appropriately selected for the combination with the protective material and the solvent, and can be selected from, for example, sodium polycarboxylate, ammonium polycarboxylate, amine polycarboxylate, polyalkylamine, polyamine and the like. In the fine particle preparation process, secondary particles generated by aggregation have a relatively large particle size, which leads to a loss of pattern uniformity. Therefore, it is desirable to appropriately filter the dispersion with a membrane filter or the like.

  The solvent of the dispersion can be changed to correspond to the surface property of the mask layer. In addition, in order to reduce the macro unevenness of coating, that is, the area where the metal fine particles are not uniformly applied, it is possible to improve the coating property by adding a binder made of a polymer material to the dispersion. A dispersion can be prepared by selecting a polymer material that is soluble in a solvent.

  Furthermore, various polymer materials can be added as a binder to the metal fine particle coating solution, thereby improving the coating property on the mask layer and enhancing the adhesion of the pattern to the base.

  The polymer material used for the binder may be any material that can be dissolved in the solvent of the coating solution. For example, polystyrene, polymethyl methacrylate, polyvinyl alcohol, polyvinyl pyrrolidone, or the like can be used.

  A metal fine particle coating solution in which metal fine particles are monodispersed in these solvents is dropped and applied onto the mask layer.

  Similarly to the resist solution and the polymer solution of the self-assembled film, the metal fine particle dispersion can be applied onto the substrate by various methods such as a spin coating method. At this time, if the metal fine particles have a localized multi-layer structure, transfer uniformity is impaired. Therefore, it is preferable to adjust the coating conditions so that a single-layer structure is formed over a wide range on the substrate.

  What is necessary is just to set the quantity of the coating liquid dripped on a mask layer to the quantity which can be fully coat | covered with respect to a desired application area. Further, when the metal fine particle layer is formed in multiple layers, various adjustments may be made to the solution concentration, the solution viscosity, and the coating conditions. For example, since the spin coating method forms a multilayer structure over a large area, it is desirable to set the coating rotation speed to 10,000 rotations or less. When the rotation speed is 10,000 rotations or more, the defect region of the metal fine particles is enlarged and it becomes difficult to form a single layer. When the metal fine particles are applied by spin coating, the defect region of the metal fine particles can be reduced on the middle and outer peripheral sides as compared with the inner periphery. For this reason, the signal S / N shows a better value in the middle and outer circumferences than in the inner circumference.

  Further, by pre-treating the surface of the mask layer, the affinity for the metal fine particle coating solution is increased, and the coating property of the metal fine particle coating solution, that is, in-plane uniformity can be improved. For example, a method of heating the substrate or applying a silane coupling agent may be mentioned, or a method of providing a high molecular material with high affinity for the solvent on the mask layer may be used.

  By performing an appropriate post-treatment on the substrate coated with metal fine particles, it is possible to enhance the adhesion of the fine particles. Specifically, a method of removing the solvent in the coating solution by heating the substrate can be mentioned. In this case, it is preferable to set a temperature at which the protective material around the fine particles is not thermally decomposed.

  As will be described later, when metal fine particles are used as a convex pattern, there is a problem that transfer accuracy of the pattern is remarkably deteriorated due to aggregation of fine particles generated during processing such as etching. Therefore, the following process can be introduced to reduce aggregation.

Specifically, the process of forming a convex pattern mask of metal fine particles that can alleviate agglomeration includes (2) the step of arranging the metal fine particles on the substrate, and (2) physically metal fine particles. A step of forming an overcoat film to be fixed; and (3) a step of irradiating energy rays to deactivate the protective material for fine particles.

  After the metal fine particles are arranged in a single layer on the substrate, an overcoat film covering the metal fine particles is formed. As described above, this overcoat film is a thin film covering the surface of the metal fine particles and the protective material.

  The overcoat film is a film that uniformly fixes the metal fine particles arranged in the same plane. When the protective material and the lower mask layer are etched, the fine particles are aggregated as the protective material is deactivated by plasma exposure or heating. On the other hand, it is possible to suppress agglomeration due to energy application required for deactivating the protective group by fixing the metal fine particles in advance with the overcoat film. In addition, since the material of the overcoat film is also formed in the gap between the protective material and the protective material, it adheres to the surface of the metal fine particles. For this reason, it has the effect | action which suppresses aggregation by reducing the chemical activity of a metal microparticle.

  The overcoat film can be selected from various materials. For example, similar to the metal fine particle material as described above, C, Pt, Ni, Pd, Co, Al, Ti, Ce, Si, Fe, Au, Ag, Cu, Ta, Zr, Zn, Mo, W, Ru, It can be selected from the group such as Ge, and further may be selected from compounds such as alloys, oxides and nitrides thereof.

  In addition, since the overcoat film has a role of deactivating the protective group by transmitting energy rays to be described later, it is desirable to make the thickness less than the thickness that blocks the energy rays, and it is preferable that the thickness be 10 nm or less. More preferable in terms of process. When it is difficult to form an overcoat film as a thin film, a thick film may be formed in advance and the film may be thinned by any etching method later.

  Subsequently, the metal particulate protective material is deactivated. Specifically, energy rays are irradiated from the outside to cut the polymer chain that is a protective material.

  When the metal fine particles lose the protective material due to the irradiation of energy rays, they immediately aggregate when the gap between the adjacent fine particles is free space. However, as described above, the protective material is physically fixed by the overcoat film. Aggregation is suppressed even if is deactivated. Furthermore, since the overcoat film formed on the protective material gap, that is, on the surface of the metal fine particles lowers the chemical activity of the metal fine particles, the metal fine particles are in a state where their aggregation is suppressed.

  The energy beam can be selected from various types, and for example, ultraviolet rays, electron beams, X-rays, and the like can be used. Moreover, when irradiating energy rays, in addition to the vacuum, an inert gas atmosphere such as He or Ar may be used. From the viewpoint of tact time, it is preferable to use ultraviolet rays as energy rays that can be irradiated more easily.

  Moreover, the energy irradiated by the energy beam can be appropriately set by various parameters such as wavelength and applied voltage.

  The overcoat film is etched and removed to provide a convex pattern made of metal fine particles on the mask.

  As described above, the overcoat film made of various materials can be easily removed by selecting an appropriate etching gas. Further, as will be described later, the convex mask pattern may be provided by processing the mask layer as a lower layer at once.

  A series of steps of overcoat film formation, energy beam irradiation, and overcoat film processing may be repeated a plurality of times, or may be performed until aggregation of metal fine particles can be suppressed.

Mask Layer Patterning Step Next, the metal fine particles are transferred as a convex pattern to the mask layer.

  In the processing of the mask layer, various layer configurations and processing methods can be realized by combining the mask layer material and the etching gas.

  When performing microfabrication, it is preferable to apply dry etching so that etching in the thickness direction is significant with respect to etching in the width direction of the convex pattern. The plasma used in dry etching can be generated by various methods such as capacitive coupling, inductive coupling, electron cyclotron resonance, and multifrequency superposition coupling. In addition, parameters such as process gas pressure, gas flow rate, plasma input power, bias power, substrate temperature, chamber atmosphere, and ultimate vacuum can be set to adjust the pattern size of the convex pattern.

When the mask material is laminated in order to increase the etching selectivity, the etching gas can be selected appropriately. Etching gas includes CF ₄ , C ₂ F ₆ , C ₃ F ₆ , C ₃ F ₈ , C ₅ F ₈ , C ₄ F ₈ , ClF ₃ , CCl ₃ F ₅ , C ₂ ClF ₅ , CCBrF ₃ , CHF ₃ Fluorine gases such as NF ₃ and CH ₂ F ₂ and chlorine gases such as Cl ₂ , BCl ₃ , CCl ₄ , and SiCl ₄ . In addition, various gases such as H ₂ , N ₂ , O ₂ , Br ₂ , HBr, NH ₃ , CO, C ₂ H ₄ , He, Ne, Ar, Kr, and Xe can be applied. It is also possible to use a mixed gas obtained by mixing two or more of these gases in order to adjust the etching rate and the etching selectivity. Patterning by wet etching is also possible, and in this case, it is preferable to select an etching solution that can secure an etching selectivity and can suppress etching in the width direction. Similarly, physical etching such as ion milling may be performed.

  As described above, one transfer layer can be provided between the mask layer and the resist layer in order to improve the pattern transfer accuracy. Furthermore, after transferring the convex pattern of the resist layer to the transfer layer, the convex pattern may be transferred to the mask layer after removing the resist layer.

  In order to remove the resist layer from the transfer layer, wet etching or dry etching can be applied. For example, an organic resist material or the like can be easily removed from the transfer layer by performing wet etching with an organic solvent. When a mask containing metal is used, wet etching can be performed by appropriately selecting a solution capable of dissolving the metal. As a result, for example, aggregation during processing such as metal fine particles can be suppressed, and clogging of the concave portion accompanying transfer of by-products due to etching and transfer accuracy deterioration can be minimized. Note that dry etching may be performed as long as the resist material can be selectively removed.

  The transfer layer layer can have various configurations in consideration of the etching selection ratio with the resist layer. As described above, for example, the transfer layer layer has a configuration such as C / Si, Ta / Al, Al / Ni, or Si / Cr from the substrate side. can do.

  When the interval between the resist convex patterns is extremely narrow, the fine particle interval may be adjusted by intentionally etching the convex portions of the resist. Specific examples include a method of increasing side etching in dry etching and a method of slimming metal fine particles in the width direction by adjusting the incident angle of ion species in ion milling. As described above, the convex pattern of the resist layer can be transferred to the mask layer.

  In addition to the method of providing a convex pattern on the resist layer as described above, there is a method of applying nanoimprint lithography. Specifically, a nanoimprint stamper is produced using a substrate or a mask pattern on the substrate as a template, and a convex pattern is transferred to a resist layer on the magnetic recording medium using the nanoimprint stamper. Although various patterns can be used for the convex pattern of the resist layer used as a template, here, a method using metal fine particles that can be manufactured at a low cost by a simpler manufacturing method will be described.

The manufacturing method of the stamper according to the embodiment is as follows:
A step of forming metal fine particles on the substrate, a step of forming an overcoat film covering the metal fine particles, a step of inactivating a protective material around the metal fine particles by irradiating energy rays, and using the metal fine particles as a mask. A step of forming a pattern, a step of forming a conductive layer having a convex pattern on a convex pattern composed of metal fine particles, a step of forming an electroformed layer using the conductive layer as an electrode, and peeling the conductive layer The method further comprises a step of forming a stamper made of an electroformed layer to which the convex pattern is transferred, and a method of manufacturing a magnetic recording medium using the same includes a step of forming a magnetic recording layer on a substrate
Forming a mask layer on the magnetic recording layer;
Forming an imprint resist layer on the mask layer;
Using a stamper to transfer a convex pattern on the imprint resist layer;
Transferring the convex pattern to the mask layer;
Transferring the convex pattern to the magnetic recording layer;
Removing the mask layer from the magnetic recording layer;
It comprises.

  Nanoimprint lithography performs pattern transfer by pressing a nanoimprint stamper (hereinafter referred to as a stamper) with a micro-convex pattern formed on its surface onto a transfer resist layer. Step-and-repeat UV exposure and electron beam exposure are used. Compared with such techniques, the resist pattern can be collectively transferred to a large area of the sample. Therefore, since the manufacturing throughput is increased, the manufacturing time can be reduced and the cost can be reduced.

The stamper can be obtained from a substrate having a fine convex pattern, that is, a so-called master master (mold, master), and is often produced by electroforming the fine pattern of the master master. As a substrate for the master master, a semiconductor substrate doped with impurities such as B, Ga, In, and P in addition to Si, SiO ₂ , SiC, SiOC, Si ₃ N ₄ , C, and the like can be used. . In addition, a substrate made of a conductive material can be used. Moreover, there is no limitation regarding the three-dimensional shape of a board | substrate, A circular, rectangular, and donut shape thing can be used.

  As described above, the master master pattern may be a metal fine particle convex pattern, or a metal fine particle pattern transferred to a mask layer can be applied as a pattern for electroforming. After transferring, this can be used as an electroforming pattern.

  Subsequently, electroforming is performed on the convex pattern of the master master to produce a stamper. Various materials can be used for electroforming, that is, plated metal. Here, as an example, a method for producing a stamper made of Ni will be described.

  In order to impart conductivity to the convex pattern of the master master, a conductive film is formed on the surface of the single layer metal fine particles. In electroforming, which will be described later, if a conductive failure occurs, plating growth is hindered and leads to pattern defects. Therefore, the conductive film is preferably formed uniformly on the surface and side surfaces of the convex pattern. However, this is not the case when a conductive material is applied to the metal fine particles and the substrate, and the convex pattern only needs to be electrically conductive. In this case, the conductive film may be formed only on the upper part, the side surface, and the groove part of the metal fine particles.

  The conductive film can be selected from various materials. Examples of the conductive film material include Ni, Al, Ti, C, Au, and Ag. Here, an example using Ni will be described.

  The conductive film formed on the metal fine particles may be integrated with the metal fine particle pattern.

  Subsequently, the master master is immersed in a sulfamic acid Ni or NiP bath and energized, and electroforming is performed to form an electroformed layer serving as a stamper on the conductive film. The film thickness after plating, that is, the thickness of the stamper can be adjusted by changing the current value, plating time, etc., in addition to the hydrogen ion concentration, temperature and viscosity of the plating bath. This electroforming can be performed by electrolytic plating or electroless plating.

  The stamper thus obtained is released from the substrate. When the metal fine particle layer remains on the convex pattern surface of the stamper, the metal fine particles remaining as a residue can be removed by etching the convex pattern surface, and the convex pattern can be exposed. Alternatively, a stripping solution in which the stamper is hardly soluble and the metal fine particles are easily soluble may be selected, and wet etching using this may be performed. Finally, unnecessary portions other than the convex pattern surface are mechanically removed and further processed into a desired shape such as a circle or a rectangle, whereby the stamper can be completed.

  As a modification of the nanoimprint stamper manufacturing process, a mask layer can be provided on the substrate, and a convex pattern can be transferred to the mask layer. As described above, the mask layer used here may be any material that can ensure an etching selectivity with the metal fine particles, and the mask layer may have a multilayer structure of two or more layers. Furthermore, it is also possible to produce a stamper by using a master master plate on which a convex pattern is transferred to a substrate via a mask layer and the convex pattern is also transferred to the substrate.

  A replica stamper can be produced by replacing the stamper as a master master. In this case, a method of obtaining a Ni stamper from a Ni stamper, a method of obtaining a resin stamper from a Ni stamper, and the like can be mentioned. Here, a method for producing a resin stamper having relatively high cost performance and easy production will be described.

  The resin stamper is manufactured by injection molding. First, a Ni stamper is loaded into an injection molding apparatus, and a resin solution material is introduced into the convex pattern of the stamper to perform injection molding. As the resin solution material, a cycloolefin polymer, polycarbonate, polymethylmethacrylate, or the like can be applied, and a material having good releasability from an imprint resist described later can be selected. After injection molding, the sample is peeled off from the Ni stamper to obtain a resin stamper having a convex pattern.

  The convex pattern can be transferred using a resin stamper. Here, as described above, a sample in which a magnetic recording layer and a mask layer are provided from the substrate side is used, and a sample in which an imprint resist layer is further formed on the mask layer is used. As the imprint resist, various resist materials including a thermosetting resin and a photocurable resin can be used. For example, isobornyl acrylate, allyl methacrylate, dipropylene glycol diacrylate, and the like can be applied.

  These resist materials are applied on a sample having a magnetic recording layer and a mask layer on a substrate to form a resist layer. Next, a resin stamper having a convex pattern is imprinted on the resist layer. At the time of imprinting, when the resin stamper is pressed onto the resist, the resist fluidizes and a convex pattern is formed. Here, by applying energy such as ultraviolet rays to the resist layer, the resist layer forming the convex pattern is cured, and then the resin stamper is released to obtain the convex pattern of the resist layer. In order to easily release the resin stamper, the surface of the resin stamper may be previously subjected to a release treatment with a silane coupling agent or the like.

Next, the resin stamper in which the imprint resist is pressed is released. Here, since the resist material remains as a residue in the recess of the resist layer after the release of the resin stamper, the surface of the mask layer is exposed by removing the resist material by etching. Since polymer-based resist materials generally have low etching resistance against O ₂ etchants, residues can be easily removed by dry etching using O ₂ gas. When an inorganic material is included, the etching gas can be changed as appropriate so that the resist pattern remains. Thereafter, after transferring the convex pattern to the mask layer and the magnetic recording layer, a magnetic recording medium having the convex pattern can be produced by nanoimprinting through a step of forming a protective film.

Magnetic Recording Layer Patterning Step Next, the convex pattern is transferred to the magnetic recording layer below the alloy release layer.

  As a typical method for forming a magnetic isolated dot, the above-described reactive ion etching, milling method and the like can be cited. Specifically, patterning can be performed by reactive ion etching using CO or NH3 as an etching gas, or ion milling using an inert gas such as He, Ne, Ar, Xe, or Kr.

  When patterning the magnetic recording layer, it is desirable that the relationship of the etching rate ERmag of the magnetic recording layer to the etching rate ERmask of the mask layer satisfies ERmask ≦ ERmag. In other words, in order to obtain a desired magnetic recording layer thickness, the smaller the mask layer receding with etching, the better.

  When a convex pattern is transferred to the magnetic recording layer by ion milling, it is necessary to suppress a so-called redepo component, which is a byproduct that scatters toward the mask side wall during processing. Since this redeposit component adheres to the periphery of the convex pattern mask, the size of the convex pattern is enlarged and the groove portion is buried, so that the redepo component is possible to obtain a divided magnetic recording layer pattern. It is desirable to reduce it. In addition, if the redeposit component generated during the etching of the magnetic recording layer below the release layer covers the side surface of the release layer, the release layer will not be exposed to the release solution, and the peelability will deteriorate. It is desirable that there are few components.

  In ion milling on the magnetic recording layer, the redeposit component on the side wall can be reduced by changing the incident angle of ions. In this case, although the optimum incident angle differs depending on the mask height, it is possible to suppress redeposition within a range of 20 ° to 70 °. Further, the incident angle of ions may be appropriately changed during milling. For example, after the magnetic recording layer is milled at an ion incident angle of 0 °, the ion incident angle is changed to selectively remove the redeposited portion of the convex pattern.

Mask Layer Removal and Stripping Step After the convex pattern is transferred to the magnetic recording layer, the mask layer existing on the magnetic recording layer is removed. If the mask layer remains on the surface of the medium without being removed, an abnormal projection pattern is formed, and the head to be scanned will crash. Therefore, it is preferably removed as much as possible.

  The mask layer can be removed by dry etching and wet etching. When dry etching is applied, an etching gas species that can remove the mask layer material is appropriately selected.

  Further, as described above, a release layer may be provided between the magnetic recording layer and the mask layer, and the release layer may be dissolved and removed to lift off the mask layer. When the peeling layer is chemically removed by dry etching, the particles adhering to the mask layer remain as a pattern, and finally the surface property of the medium is deteriorated. When the peeling layer is dissolved by wet etching, the mask layer and particles are lifted off, and are completely removed from the surface of the medium. Therefore, deterioration of the surface property of the medium can be minimized. Therefore, wet etching is more preferable for removing the mask on the magnetic recording layer.

  As described above, since the release layer contains a metal material that is soluble by an acid or alkali solution, an etching solution that can dissolve the metal material can be appropriately selected. Examples of the acid stripping solution include hydrochloric acid, phosphoric acid, nitric acid, boric acid, perchloric acid, hydrobromic acid, carboxylic acid, sulfonic acid, and hydrogen peroxide solution.

  In the alkaline stripping solution, for example, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, potassium hydroxide aqueous solution, calcium hydroxide aqueous solution, barium hydroxide aqueous solution, magnesium hydroxide aqueous solution, ammonium hydroxide aqueous solution, hydrazine, tetramethylammonium hydroxide, Examples thereof include tetrapropylammonium hydroxide and phenyltrimethylammonium hydroxide. A buffer solution for adjusting the pH of the solution may be added as appropriate.

  When the release layer is dissolved by wet etching, it is desirable that the dissolution rate with respect to the magnetic recording layer and the substrate is sufficiently smaller than the dissolution rate of the release layer.

Step of forming protective layer After removing the mask layer on the magnetic recording layer, a protective layer is formed on the convex pattern. This protective film plays a role of preventing corrosion of the convex patterned magnetic recording layer and preventing abrasion of the medium surface that occurs during head scanning.

  When a protective film is formed on a narrow pitch pattern, if the film is simply formed, a difference in film thickness occurs between the protective film on the convex pattern and the protective film on the concave pattern portion, and the flying characteristics of the head deteriorate. There's a problem. Further, when flattening is performed by embedding only the concave pattern with a protective film material, it is difficult to flatten in a later process, and the location dependence of the unevenness difference becomes significant, and there is a problem that the flatness of the medium deteriorates. . Therefore, it is difficult to completely fill a convex pattern with a narrow pitch pattern with a protective film material, and at the same time, there is a problem that flatness after embedding is deteriorated.

  On the other hand, by forming the protective film on the convex pattern by oblique film formation as in the manufacturing method described above, the protective film is uniformly formed on the pattern without impairing the flatness of the medium surface. be able to.

  The pattern of the magnetic recording layer is a periodic convex shape as described above, and can take various structures. For example, a cylinder, a cone, a prism, a pyramid, a polygonal column, a polygonal pyramid, and the like. It is not necessary that all dot patterns on the substrate have a single shape, and the dots having the shape may be mixed on the substrate regardless of the number and types thereof.

  The pattern pitch with which the protective film can be satisfactorily formed is 20 nm or less. This is because if the pitch is wider than this, the protective film is uniformly coated on the side surface and the bottom surface of the dots, so that the convex pattern cannot be embedded. Here, the pitch is a distance from the center of gravity of a certain convex dot pattern on the substrate to the center of gravity of an adjacent convex pattern. That is, the term “periodic” refers to a state in which the pitch is continuous twice or more with a certain dot as a reference. The dot pattern on the medium is preferably arranged uniformly in the plane, but the pitch and the dot size have variations, that is, dispersion. This dispersion is preferably 20% or less in order to make the signal S / N from the medium highly sensitive.

  Further, the pitch is not necessarily periodic due to a pattern defect or the like, and it is only necessary that the pitch is periodic again even if the pitch is interrupted at a discontinuous value at a certain location. This discontinuous point is caused by, for example, a defect in the resist convex pattern. Specifically, in the electron beam resist pattern described above, there is a pattern defect due to electron beam drawing failure or development failure, and in the self-assembled diblock copolymer material, this is a so-called domain region in which the self-assembled pattern is macroscopically discontinuous. It corresponds to. Further, in the metal fine particle pattern, it is a defect region of fine particles that are not arranged on the mask, and in nanoimprint, a defect due to imprint transfer failure corresponds to this. In any case, even if a discontinuous region once occurs, there is no problem in terms of the medium configuration as long as a periodic pattern is arranged again.

  The protective film material can be selected from various materials, but is preferably a nonmagnetic material. Specifically, selected from Al, Si, C, Ti, V, Cr, Mn, Cu, Zn, Ge, Y, Zr, Mo, Pd, Ag, Hf, W, Pt, Au, alloys thereof, Alternatively, it may be composed of a compound such as an oxide or a nitride. Further, when a carbon material is used, a DLC film containing a large amount of sp3 bonded carbon is preferable.

  The thickness of the protective film material is preferably 5 nm or less in order to improve the signal S / N by reducing the magnetic spacing. This is because when the thickness is greater than 5 nm, it becomes difficult to convert an electric-magnetic signal. Moreover, in order to make the coverage with respect to a convex pattern favorable, it is desirable to make it thicker than 0.1 nm. This is because if it is thinner than 0.1 nm, the covering property is deteriorated.

  The protective film is obtained by forming a protective film material obliquely on the magnetic recording layer convex pattern. When the protective film material is obliquely formed on the substrate surface, the sample jig is inclined with respect to the fixed protective film material source, the sample substrate loaded on the jig is inclined, or For example, the protective film material source may be inclined with respect to the fixed substrate material. At this time, the angle of oblique film formation may be appropriately changed during the formation of the protective film, and a plurality of irradiation angles can be set. For example, the irradiation angle may be changed to θ1, θ2, θ3,.

  As a film formation method by oblique incidence, for example, a method such as vacuum vapor deposition, sputtering, or ion beam vapor deposition may be applied. During film formation, it is possible to improve the film formation uniformity of the irradiated protective film material by rotating the substrate loaded with the sample or revolving the sample jig with respect to the material source. is there.

  Further, after forming the protective film material as a thick film by oblique incidence, a film thickness reduction process by etching may be performed to reduce the surface roughness. Specifically, wet etching or dry etching can be applied. However, in order to ensure in-plane uniformity and a processing margin for a thin film, it is preferable to apply dry etching. This film thickness reduction process can be variously combined with the film formation process by oblique incidence. For example, after forming a protective film material by oblique incidence at a certain angle θ1, the film thickness is reduced by dry etching, and then oblique incidence at an angle θ2 for reducing the convex pattern is performed. For example, the film thickness is reduced again by dry etching.

  Further, the protective film material can be formed by another method with respect to the protective film material formed by oblique incidence. For example, it is possible to form a single-layer protective film on a flat protective film obtained by applying a solution containing a protective film material and obliquely incident. Thereby, the unevenness difference caused by oblique incidence can be reduced. After the coating and film formation, the thickness of the protective film may be adjusted to a desired value by performing the dry etching described above.

  The solution containing the protective film material can be applied by various methods. For example, methods such as a spin coating method, a dip coating method, a spin casting method, a Langmuir Blodget method, and an ink jet method can be applied.

  The protective film formed on the magnetic recording layer connects the convex-convex patterns of the magnetic recording layer in a bridge shape. Accordingly, a portion surrounded by the magnetic recording layer and the upper protective film becomes a void region.

  Since this gap area reduces the unevenness of the surface of the medium, the vortex of the air current at the time of flying the head does not occur in the concave pattern. Accordingly, since the turbulence of the air current on the medium surface, that is, the turbulence is reduced, the head stagnation to the substrate surface due to the vortex and the pressure difference is suppressed. Therefore, the vibration during head scanning is reduced, the flying stability is improved, the frequency with which the head contacts the surface of the medium is reduced, and a crash can be avoided.

The air gap may be constituted by an air atmosphere, a vacuum atmosphere, or an inert gas atmosphere. For example, it is possible to replace the void region as it is in a gas atmosphere required during film formation, and specific gases include He, N ₂ , Ar, Ne, and the like.

  The protective layer has a different thickness depending on the position of the periodic pattern of the magnetic recording layer. Specifically, between XX ′ where the pattern is closest, the protective layer thickness at the top of the dot is t1, the protective layer thickness between the dots is t2, and between YY ′ where the pattern is remotest, When the protective layer thickness between dots is t3, the condition is t1 ≦ t2 ≦ t3.

  Finally, by forming a fluorine-based lubricating film (not shown) on the protective film, it is possible to obtain a magnetic recording medium constituted by the convex pattern magnetic recording layer and a protective film connecting them at the upper part. As the lubricant, perfluoropolyether, fluorinated alcohol, fluorinated carboxylic acid, or the like can be used.

  FIG. 19 shows an example of a recording bit pattern with respect to the circumferential direction of the magnetic recording medium.

In FIG. 19, the data area on the magnetic recording medium and the servo area that is the positioning information of the magnetic head are all configured by a periodic pattern. At this time, the number of dots for recording / reproducing one bit can be composed of one or more.

  FIG. 20 is a partially exploded perspective view showing an example of a magnetic recording / reproducing apparatus to which the magnetic recording medium according to the embodiment can be applied.

  This figure shows the internal structure of the hard disk drive according to the embodiment with the top cover removed as a disk device. As shown in the figure, the HDD includes a housing 210. The housing 210 includes a rectangular box-shaped base 211 having an open top surface and a rectangular plate-shaped top cover (not shown). The top cover is screwed to the base with a plurality of screws, and closes the upper end opening of the base. As a result, the inside of the casing 210 is kept airtight and can be ventilated to the outside only through the breathing filter 226.

  On the base 211, a magnetic disk 212 as a recording medium and a drive unit are provided. The drive unit includes a spindle motor 213 that supports and rotates the magnetic disk 212, a plurality of, for example, two magnetic heads 233 that record and reproduce information on the magnetic disk, and these magnetic heads 233 on the surface of the magnetic disk 212. A head actuator 214 movably supported on the head and a voice coil motor (hereinafter referred to as VCM) 216 for rotating and positioning the head actuator are provided. On the base 211, when the magnetic head 233 moves to the outermost periphery of the magnetic disk 212, an impact or the like acts on the ramp load mechanism 218 that holds the magnetic head 233 at a position separated from the magnetic disk 212, or the HDD. In addition, an inertia latch 220 that holds the head actuator 214 in the retracted position, and a substrate unit 217 on which electronic components such as a preamplifier and a head IC are mounted are provided.

  A control circuit board 225 is screwed to the outer surface of the base 211 and is positioned to face the bottom wall of the base 211. The control circuit board 225 controls operations of the spindle motor 213, the VCM 216, and the magnetic head 233 via the board unit 217.

  In FIG. 20, a magnetic disk 212 is configured as a perpendicular magnetic recording medium having a convex pattern formed by the above-described processing method. Further, as described above, the magnetic disk 212 includes the substrate 219 made of a nonmagnetic material and formed in a disk shape having a diameter of about 2.5 inches, for example. On each surface of the substrate 219, a soft magnetic layer 223 as an underlayer, and a perpendicular magnetic recording layer 222 having magnetic anisotropy in a direction perpendicular to the disk surface are sequentially laminated on the upper layer, and further A protective film 224 is formed thereon.

  The magnetic disk 212 is clamped by a clamp spring 221 that is coaxially fitted to the hub of the spindle motor 213 and screwed to the upper end of the hub, and is fixed to the hub. The magnetic disk 212 is rotated in the arrow B direction at a predetermined speed by a spindle motor 213 as a drive motor.

  The head actuator 214 includes a bearing portion 215 fixed on the bottom wall of the base 211 and a plurality of arms 227 extending from the bearing portion. These arms 227 are located in parallel to the surface of the magnetic disk 212 and at a predetermined interval from each other, and extend from the bearing portion 215 in the same direction. The head actuator 214 includes an elongated plate-like suspension 230 that can be elastically deformed. The suspension 230 is configured by a leaf spring, and the base end thereof is fixed to the distal end of the arm 227 by spot welding or adhesion, and extends from the arm. A magnetic head 233 is supported on the extended end of each suspension 230 via a gimbal spring 241. The suspension 230, the gimbal spring 241 and the magnetic head 233 constitute a head gimbal assembly. The head actuator 214 may include a so-called E block in which a sleeve of the bearing portion 215 and a plurality of arms are integrally formed.

  Hereinafter, an example is shown and an embodiment is described concretely.

(C protective layer, EB lithography)
First, a manufacturing method characterized by forming a convex pattern on a resist layer by electron beam lithography and then transferring it to a magnetic recording layer will be described.

  A 2.5-inch diameter donut substrate was used as the substrate, and a magnetic recording layer was formed thereon by DC sputtering. The process gas is Ar, the gas pressure is set to 0.7 Pa, the gas flow rate is set to 35 sccm, and the input power is set to 500 W. From the substrate side, a 10 nm thick NiTa underlayer / 4 nm thick Pd underlayer / 20 nm thick Ru underlayer / 5 nm thick CoPt recording layer A magnetic recording layer was obtained by sequentially forming films and finally forming a 3 nm thick Pd protective layer.

  Subsequently, an underlayer for reducing the roughness of the release layer was formed on the magnetic recording layer. Here, a Pd film was selected, and the film was formed by DC sputtering so as to have a thickness of 1.5 nm. Further, here, in order to intentionally increase the roughness, the film was formed by increasing the process gas pressure to 4.0 Pa to obtain a Pd film having a surface roughness of 0.32 nm. Subsequently, a metal release layer was formed on the base layer. In this example, Mo soluble in acid was selected as the release layer, and the film was formed to a thickness of 5 nm by DC sputtering.

  Subsequently, a mask layer was formed on the release layer. Here, a two-layer mask is used to transfer the convex pattern of the resist layer with high definition, and 30 nm thickness C is applied as the first mask layer from the substrate side, and 5 nm thickness Si is applied as the upper transfer layer. Each mask layer was formed by sputtering using an opposed target type DC sputtering apparatus with an Ar gas flow rate of 35 sccm, an Ar gas pressure of 0.7 Pa, and an input power of 500 W.

  Next, a main chain cutting type electron beam positive resist for patterning was formed. ZEP-520A manufactured by Nippon Zeon Co., Ltd. was used as the electron beam resist, and the solution was diluted to a weight ratio of ZEP-520A: anisole = 1: 3 using anisole as a solvent. It spin-coated so that it might become 30 nm thickness at 2500 rpm. The sample was held on a vacuum hot plate heated to 180 ° C. for 150 seconds and pre-baked to cure the electron beam resist.

  Next, a pattern was drawn on the electron beam resist using an electron beam drawing apparatus having a ZrO thermal field emission electron source and having a beam with an acceleration voltage of 100 kV and a beam diameter of 2 nm. The electron beam drawing apparatus is a so-called x-θ type drawing apparatus including a signal for forming a drawing pattern, a one-way moving mechanism of a sample stage, and a concentric rotating mechanism. In drawing the sample, the signal for deflecting the electron beam is synchronized and the stage is moved in the radial direction. Here, the drawing linear velocity was 0.15 m / sec, the beam current value was 13 nA, the feed amount in the radial direction was 5 nm, and a dot / space pattern and a line / space pattern latent image having a pitch of 20 nm were formed on the electron beam resist. .

  By developing this, a convex pattern of 10 nm diameter dots / 5 nm space, 10 nm width line / 10 nm width space can be resolved. An organic developer containing 100% normal amyl acetate as a developer was used as the developer, and the electron beam resist was developed by immersing the sample in the solution for 20 seconds.

Subsequently, the sample was immersed in isopropyl alcohol for 20 seconds for rinsing, and the sample surface was dried by direct blowing of N ₂ .

The convex pattern was transferred to the mask layer by dry etching. In dry etching, inductively coupled plasma etching using CF ₄ gas and O ₂ gas was applied. First, in order to transfer the convex pattern to the Si transfer layer below the resist, CF ₄ gas pressure was 0.1 Pa, gas flow rate was 20 sccm, input power was 100 W, bias power was 10 W, and the resist convex pattern was transferred by etching for 40 seconds. Subsequently, O ₂ gas was used to etch the C mask layer, the gas pressure was 0.1 Pa, the gas flow rate was 20 sccm, the input power was 100 W, and the bias power was 20 W, and the convex pattern was transferred by etching for 65 seconds.

  Next, the convex pattern was transferred to the release layer and the magnetic recording layer. As described above, in transferring the convex pattern to the release layer and the magnetic recording layer, each layer may be separately patterned through different etching processes, but the same process may be used. Here, a milling method using Ar ions was applied. Milling was performed for 110 seconds at an Ar ion acceleration voltage of 300 V, a gas flow rate of 3 sccm, a process pressure of 0.1 Pa, and an incident angle of 90 ° (normal incidence) of ion species with respect to the substrate surface, and a 6 nm thick Pd / W alloy release layer and a 5 nm thick CoPt The convex pattern was transferred to the recording layer.

  Subsequently, wet stripping was performed to strip the mask pattern. As described above, since the W alloy layer that enables acid peeling is used as the peeling layer, wet peeling was performed using hydrogen peroxide. The hydrogen peroxide solution was prepared to have a weight percent concentration of 1%, and the sample was immersed for 3 minutes. Subsequently, the sample was washed with pure water for 5 minutes to clean the medium surface. Thereby, the mask layer and the release layer were removed from the magnetic recording layer.

  Next, a protective layer was formed. As described above, this protective layer is formed on the top of the convex-convex pattern of the magnetic recording layer by oblique incidence. Here, C was selected as the protective layer material, and the film was formed by DC sputtering so that the gas pressure was 2 Pa, the input power was 200 W, the irradiation angle was 72 °, and the film thickness was 2 nm.

  Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

  First, when an upper surface SEM observation was performed in order to confirm the cross-sectional shape of the obtained magnetic recording medium, a polygonal periodic pattern could be clearly confirmed. Further, when a cross-sectional TEM image was taken, it was found that there was a trapezoidal magnetic recording layer pattern having a 5 nm convex pattern. Furthermore, EELS analysis was performed to confirm the protective layer region. Here, when the region without the protective layer material is 0 and the region filled with the protective layer material is 1, the element concentration is identified by obtaining the relative value of the detected intensity. As a result, it was found that the magnetic recording layer convex-convex pattern and the C protective layer existed on the convex pattern, and that a gap was generated between the recording layers. At this time, the result of the detected amount of the protective layer element confirmed that the protective layer material concentration on the side surface of the magnetic recording layer was 98 atomic% on the substrate surface, which was a high concentration.

  The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed.

  Finally, the recording / reproduction characteristics of these media were evaluated by measuring the electromagnetic conversion characteristics using a read / write analyzer RWA1632 manufactured by GUZIK, USA and a spin stand S1701MP. For evaluation of recording / reproducing characteristics, a shielded pole magnetic pole, which is a single pole magnetic pole with a shield for writing (the shield has a function of converging the magnetic flux emitted from the magnetic head), and a head using a TMR element for the reproducing portion are used. The signal-to-noise ratio (SNR) was measured with the recording frequency condition set to a linear recording density of 1200 kBPI. As a result, a value of 12.3 dB could be obtained as the SNR value of the medium.

  Thereby, it was found that the flying characteristics of the head and the in-plane uniformity of the convex pattern were good.

(C protective layer, self-organized lithography)
In Example 2, a microphase separation structure was formed using a self-assembled film instead of using ZEP-520A for the resist layer, and etching was performed based on the microphase separation pattern, and the self-assembled film and the mask layer were separated. In order to improve the pattern transfer, it is the same as Example 1 except that a Si / C film is further inserted between the mask layer.

  First, a carbon film for self-organized pattern transfer was formed with a thickness of 3 nm on the Si transfer layer. Here, the film was formed by DC sputtering with an Ar gas pressure of 0.7 Pa and an input power of 500 W.

  Subsequently, a block copolymer solution was applied onto the carbon film. As the block copolymer solution, a solution obtained by dissolving a block copolymer composed of polystyrene and polydimethylsiloxane in a coating solvent was used. The molecular weights of polystyrene and polydimethylsiloxane are 11700 and 2900, respectively. From this composition, a microphase separation structure with a pattern pitch of 20 nm is obtained. Propylene glycol monomethyl ether acetate was used as a solvent, and a polymer solution was prepared so as to have a weight percent concentration of 1.5%.

  This solution was dropped on a carbon film mask and spin-coated at a rotational speed of 5000 rpm to form a self-assembled film having a thickness of 18 nm to be a single-layer self-assembled film. A single-layer self-assembled film means that the microphase separation pattern of sea-like polystyrene and island-like polydimethylsiloxane does not have a hierarchical structure with respect to the same plane of the medium. The spin-coated self-assembled film is less dependent on the outer peripheral side than the inner peripheral side due to the location-dependent wettability of the coating liquid on the mask layer surface during application. . This is strongly related to the radial dependency of the signal S / N described later.

  Furthermore, thermal annealing was performed to microphase-separate the sea-like polystyrene and island-like polydimethylsiloxane dot patterns inside the self-assembled film. In thermal annealing, a vacuum heating furnace was used, and annealing was performed at 170 ° C. for 12 hours in a reduced pressure atmosphere with a furnace pressure of 0.2 Pa to form a microphase separation structure composed of 20 nm pitch dots inside the self-assembled film.

  Subsequently, a convex pattern was formed by etching based on the phase separation pattern. Etching was performed by inductively coupled plasma type reactive ion etching. The process gas pressure was 0.1 Pa and the gas flow rate was 5 sccm.

First, in order to remove polydimethylsiloxane on the surface layer of the self-assembled film, etching was performed for 7 seconds with an antenna power of 50 W and a bias power of 5 W using CF ₄ gas as an etchant. Next, in order to transfer the convex pattern to sea polystyrene and C film below the self-assembled film, etching was performed for 110 seconds with an antenna power of 100 W and a bias power of 5 W using O ₂ gas as an etchant. Since the O ₂ etchant used for removing the polystyrene also etches the underlying C film, the Si transfer layer becomes a stopper layer and the etching stops. Furthermore, the convex pattern of the self-assembled film is transferred to the mask layer by performing etching on the lower Si transfer layer and C mask layer by plasma etching using CF ₄ etchant and O ₂ etchant as in Example 1. did.

Thereafter, a magnetic recording medium having a convex pattern was obtained through a pattern transfer and peeling process in the same manner as in Example 1.

  FIG. 23 shows a top SEM photographic image of the obtained magnetic recording medium.

  As shown in the figure, it can be seen that polygonal magnetic recording dots are closely packed on the substrate surface. The pitch of the magnetic recording dots is about 20 nm. Although a dot defect is recognized locally, it does not appear that the pitch around the defect area is affected.

  FIG. 24 shows a cross-sectional TEM photographic image of the magnetic recording medium obtained.

  The irregularities in the figure are the produced CoPt dot pattern, and the upper part thereof is covered with a C protective layer formed by oblique irradiation. The C protective layer covers the upper part of the dot and the concave part in a bridge shape, and it can be confirmed that there is a gap region without the protective layer material between the convex patterns.

  The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 12.1 dB could be obtained as the SNR value of the medium. Further, it was found that the signal SNR on the outer circumference was better than that on the inner circumference and the middle circumference and was 12.8 dB.

(C protective layer, metal fine particle lithography)
In Example 3, a magnetic recording layer, a mask layer, and a metal fine particle layer are formed on a substrate, and then a convex pattern is transferred to the magnetic recording layer. As will be described later, Examples 1 to 4 are examples in which the type of energy beam to be irradiated and the irradiation atmosphere are changed in order to remove and deactivate the protective material around the metal fine particle layer.

  A 2.5-inch diameter donut substrate was used as the substrate, and a magnetic recording layer was formed thereon by DC sputtering. The process gas is Ar, the gas pressure is set to 0.7 Pa, the gas flow rate is set to 35 sccm, and the input power is set to 500 W. From the substrate side, a 10 nm thick NiTa underlayer / 4 nm thick Pd underlayer / 20 nm thick Ru underlayer / 5 nm thick CoPt recording layer A magnetic recording layer was obtained by sequentially forming films and finally forming a 3 nm thick Pd protective layer.

  Subsequently, a mask layer was formed on the Pd protective layer. Here, a three-layer mask is used to transfer the convex pattern of the metal fine particle layer with high definition. From the substrate side, the first mask layer is 30 nm thick C, the upper transfer layer is 5 nm thick Si, A 3 nm thickness C was applied as the third mask layer. Each mask layer was formed by sputtering using an opposed target type DC sputtering apparatus with an Ar gas flow rate of 35 sccm, an Ar gas pressure of 0.7 Pa, and an input power of 500 W.

  Next, a coating solution for forming a metal fine particle mask was prepared. The coating solution used was a mixed solution of a dispersion of metal fine particles and a polymer binder.

  Au having an average particle diameter of 8 nm whose surface is coated with alkanethiol groups was used as the metal fine particles. Polystyrene having an average molecular weight of 2800 was used as the polymer binder, and the metal fine particles were mixed so that the weight ratio was Au: polystyrene = 2: 3. Further, the solvent was toluene, and the solution was prepared by diluting to a weight percent concentration of 3.5%. Finally, a coating solution was prepared by dispersing the metal fine particle solution using an ultrasonic disperser and promoting monodispersion of each fine particle. When monodispersing metal fine particles, a fine particle dispersant, that is, a surfactant may be added.

  Next, a metal fine particle resist layer was formed on the C film. An appropriate amount of the prepared metal fine particle coating solution was dropped onto the C film and spin coated at a rotational speed of 4500 rpm to obtain a metal fine particle layer on the substrate. Similarly to the self-assembled film of Example 2, the metal fine particle layer also has fewer macro defects on the outer peripheral side than on the inner peripheral side after spin coating. Furthermore, the dispersion medium of the metal fine particle layer was removed by baking the substrate, and the adhesion to the substrate was strengthened. Baking was performed on a hot plate at a temperature of 140 ° C. and a holding time of 5 minutes.

  Next, an overcoat film was formed on the metal fine particle layer. This overcoat film plays a role of fixing fine particles by uniformly covering the metal fine particle layer from the upper surface. A C film was used as the overcoat film.

The C film was formed by DC sputtering, with a gas pressure of 0.7 Pa, a gas flow rate of 35 sccm, and an input power of 500 W so that the thickness was 3 nm from the surface of the metal fine particles.

  Subsequently, energy rays were irradiated from above the overcoat film. When the energy beam is irradiated, the energy beam transmitted through the overcoat film is irradiated to the protective material around the metal fine particle, the polymer chain constituting the protective material is cut, and the activity of the metal fine particle is lowered. In addition, since the material of the overcoat film adheres to the surface of the metal fine particles so as to fill the protective material gap, aggregation after processing is less likely to occur.

Here, energy rays were irradiated as ultraviolet rays in a vacuum atmosphere. In the irradiation process, after loading a sample in a vacuum vessel, the inside of the vessel was evacuated and irradiated with ultraviolet rays for 30 seconds when it reached the 10 ⁻² Pa level. Thereafter, the container was vented with N ₂ gas to collect the sample. Although the wavelength of the irradiated ultraviolet light is 365 nm, the value is not limited to this example, and ultraviolet light having various wavelengths may be irradiated.

Subsequently, the overcoat film above the metal fine particle layer and the C film below the metal fine particle layer are collectively removed by dry etching using an O ₂ etchant. In dry etching, inductively coupled plasma etching was applied, the pressure was set to 0.1 Pa, the gas flow rate was 20 sccm, the input power was 40 W, and the bias power was 40 W. The pattern was transferred to the C mask by etching for 8 seconds. The time required for transferring the metal fine particle pattern from the application of the metal fine particles, that is, the tact time is about 38 minutes. This example is an example in which the tact time can be significantly shortened compared to the comparative example described later, and the manufacturing throughput can be improved.

  After transferring the convex pattern to the C film, it is possible to transfer the pattern to the lower layer using the upper metal fine particles as a mask. In order to completely suppress the aggregation of the fine particles generated during processing, the fine particles are removed from the substrate. It may be removed. Here, the metal fine particles were dissolved and removed after the convex pattern was transferred to the C mask.

  An aqueous solution composed of iodine / potassium iodide / water was used for dissolution of the Au fine particles, and the solutions were prepared so that the respective weight ratios were 1: 2: 3. Subsequently, the sample was immersed in the mixed solution for 10 seconds and then washed with running ultrapure water for 60 seconds to dissolve and remove the metal fine particle layer from the substrate.

  In the following examples, unless otherwise specified, a step of removing the metal fine particles from the substrate after transferring the convex pattern under the metal fine particle layer is included.

Subsequently, the pattern was transferred to the underlying Si and C masks. The transfer of this pattern was performed by the above-described inductively coupled plasma etching. In the convex pattern transfer to the Si film, etching was performed for 5 seconds using CF ₄ gas as an etchant, gas pressure of 0.1 Pa, gas flow rate of 20 sccm, input power of 100 W, and bias power of 30 W.

Further, the pattern was transferred to the lower C mask. In the pattern transfer to the C film, an O ₂ etchant was used, the gas pressure was 0.1 Pa, the gas flow rate was 20 sccm, the input power was 40 W, the bias power was 40 W, and the convex pattern was transferred to the mask layer by etching for 28 seconds.

  Next, the convex pattern was transferred to the magnetic recording layer. Here, a milling method using Ar ions was applied. Milling is performed for 65 seconds at an Ar ion acceleration voltage of 300 V, a gas flow rate of 3 sccm, a process pressure of 0.1 Pa, and an incident angle of 90 ° (perpendicular incidence) of ion species with respect to the substrate surface, and convex to a 5 nm thick CoPt recording layer / 3 nm thick Pd layer The pattern was transcribed. Further, in order to remove the remaining mask layer, by milling for 5 seconds at an Ar ion acceleration voltage of 100 V, a gas flow rate of 3 sccm, a process pressure of 0.1 Pa, and an incident angle of 90 ° (normal incidence) of ion species with respect to the substrate surface, The mask layer was removed from the magnetic recording layer.

  Thereafter, a protective layer was formed in the same manner as in Example 1, and finally a perfluoropolyether lubricant film was formed with a thickness of 1.5 nm to obtain a magnetic recording medium having a convex pattern.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, it was possible to obtain a value of 12.8 dB as the SNR value of the medium. Further, it was found that the signal SNR on the outer periphery was better than that on the inner periphery and the intermediate periphery and was 13 dB.

(C protective layer, metal fine particle lithography)
Example 4 is the same as Example 3 except that one more Si layer is added as a transfer layer on the mask layer.

The Si transfer layer was formed by DC sputtering so as to have a thickness of 3 nm with a gas pressure of 0.7 Pa and an input power of 500 W. The Si transfer layer is processed by inductively coupled plasma etching using CF ₄ as an etchant, and a convex pattern is formed by etching for 7 seconds at a gas pressure of 0.1 Pa, a gas flow rate of 20 sccm, an input power of 100 W, and a bias power of 30 W. Transcribed.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 12.4 dB could be obtained as the SNR value of the medium.

(Al protective layer, metal fine particle lithography)
Example 5 is the same as Example 4 except that the protective layer material formed by oblique film formation is Al.

The Al protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 11 dB could be obtained as the SNR value of the medium.

(Si protective layer, metal fine particle lithography)
Example 6 is the same as Example 4 except that the protective layer material formed by oblique film formation is Si.

The Si protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 12.1 dB could be obtained as the SNR value of the medium.

(Ti protective layer, metal fine particle lithography)
Example 7 is the same as Example 4 except that the protective layer material formed by oblique film formation is Ti.

The Ti protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 10.8 dB could be obtained as the SNR value of the medium.

(V protective layer, metal fine particle lithography)
Example 8 is the same as Example 4 except that the protective layer material formed by oblique film formation is V.

The V protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 11.1 dB could be obtained as the SNR value of the medium.

(Cr protective layer, metal fine particle lithography)
Example 9 is the same as Example 4 except that the protective layer material formed by oblique film formation is Cr.

The Cr protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 12 dB could be obtained as the SNR value of the medium.

(Mn protective layer, metal fine particle lithography)
Example 10 is the same as Example 4 except that the protective layer material formed by oblique film formation is Mn.

The Mn protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 10.8 dB could be obtained as the SNR value of the medium.

(Cu protective layer, metal fine particle lithography)
Example 11 is the same as Example 4 except that the protective layer material formed by oblique film formation is Cu.

The Cu protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 11.2 dB could be obtained as the SNR value of the medium.

(Zn protective layer, metal fine particle lithography)
Example 12 is the same as Example 4 except that the protective layer material formed by oblique film formation is Zn.

The Zn protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 12.5 dB could be obtained as the SNR value of the medium.

(Ge protective layer, metal fine particle lithography)
Example 13 is the same as Example 4 except that the protective layer material formed by oblique film formation is Ge.

The Ge protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 10.9 dB could be obtained as the SNR value of the medium.

(Y protective layer, metal fine particle lithography)
Example 14 is the same as Example 4 except that the protective layer material formed by oblique film formation is Y.

The Y protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 11.8 dB could be obtained as the SNR value of the medium.

(Zr protective layer, metal fine particle lithography)
Example 15 is the same as Example 4 except that the protective layer material formed by oblique film formation is Zr.

The Zr protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 12.2 dB could be obtained as the SNR value of the medium.

(Mo protective layer, metal fine particle lithography)
Example 16 is the same as Example 4 except that the protective layer material formed by oblique film formation is Mo.

The Mo protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 11.6 dB could be obtained as the SNR value of the medium.

(Pd protective layer, metal fine particle lithography)
Example 17 is the same as Example 4 except that the protective layer material formed by oblique film formation is Pd.

The Pd protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, it was possible to obtain a value of 12.8 dB as the SNR value of the medium.

(Ag protective layer, metal fine particle lithography)
Example 18 is the same as Example 4 except that the protective layer material formed by oblique film formation is Ag.

The Ag protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 10.3 dB could be obtained as the SNR value of the medium.

(Hf protective layer, metal fine particle lithography)
Example 19 is the same as Example 4 except that the protective layer material formed by oblique film formation is Hf.

The Hf protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 11.2 dB could be obtained as the SNR value of the medium.

(W protective layer, metal fine particle lithography)
Example 20 is the same as Example 4 except that the protective layer material formed by oblique film formation is W.

The W protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 11.5 dB could be obtained as the SNR value of the medium.

(Pt protective layer, metal fine particle lithography)
Example 21 is the same as Example 4 except that the protective layer material formed by oblique film formation is Pt.

The Pt protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 12 dB could be obtained as the SNR value of the medium.

(Au protective layer, metal fine particle lithography)
Example 22 is the same as Example 4 except that the protective layer material formed by oblique film formation is Au.

The Au protective layer was formed obliquely by a DC sputtering method to a thickness of 2 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 10.9 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, film thickness 3nm)
Example 23 is the same as Example 3 except that the protective layer material formed by oblique film formation is C and the thickness is 3 nm.

  As in Example 3, the C protective layer was formed by DC sputtering so that the gas pressure was 2 Pa, the input power was 200 W, the C irradiation angle with respect to the pattern surface was 72 °, and the film thickness was 3 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, a protective layer material was formed by oblique film formation. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 10.7 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, film thickness 3nm)
Example 24 is the same as Example 23 except that the protective layer material formed by oblique film formation is C and the thickness is 3 nm.

  As in Example 23, the C protective layer was formed by DC sputtering so that the gas pressure was 2 Pa, the input power was 200 W, the C irradiation angle with respect to the pattern surface was 72 °, and the film thickness was 4 nm.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 9.8 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, irradiation angle 40 °)
Example 25 is the same as Example 3 except that the oblique film formation angle of the protective layer formed on the medium is changed to 40 °.

  Similar to Example 3, the sample was loaded on a disk jig having a rotation mechanism facing the protective layer material irradiation source, and the sample was arranged so that the irradiation angle was 40 °.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, a protective layer material was formed by oblique film formation. The obtained C protective film had a thickness of nm. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 11.5 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, irradiation angle 50 °)
Example 26 is the same as Example 3 except that the oblique film formation angle of the protective layer formed on the medium is changed to 50 °.

  In the same manner as in Example 3, the sample was loaded on a disk jig having a rotation mechanism facing the protective layer material irradiation source, and the sample was arranged so that the irradiation angle was 50 °.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, a protective layer material was formed by oblique film formation. The obtained C protective film had a thickness of nm. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 12.2 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, irradiation angle 60 °)
Example 27 is the same as Example 3 except that the oblique film formation angle of the protective layer formed on the medium is changed to 60 °.

  Similar to Example 3, the sample was loaded on a disk jig having a rotation mechanism facing the protective layer material irradiation source, and the sample was arranged so that the irradiation angle was 60 °.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. The obtained C protective film had a thickness of nm. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 12 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, irradiation angle 70 °)
Example 28 is the same as Example 3 except that the oblique deposition angle of the protective layer formed on the medium is changed to 70 °.

  As in Example 3, the sample was loaded on a disk jig having a rotation mechanism facing the protective layer material irradiation source, and the sample was placed so that the irradiation angle was 70 °.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. The obtained C protective film had a thickness of nm. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 12.4 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, irradiation angle 80 °)
Example 29 is the same as Example 3 except that the oblique deposition angle of the protective layer formed on the medium is changed to 80 °.

  Similar to Example 3, the sample was loaded on a disk jig having a rotation mechanism facing the protective layer material irradiation source, and the sample was arranged so that the irradiation angle was 80 °.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. The obtained C protective film had a thickness of nm. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 11.4 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, pitch 18 nm)
Example 30 is the same as Example 30 except that a convex pattern is transferred to the magnetic recording layer using a metal fine particle layer having an average particle diameter of 12 nm and a pitch of 18 nm.

  In this example, Au was used for the metal fine particles. Au was prepared and applied in the same manner as in Example 3 to form a fine particle layer on the substrate. Further, a protective layer was formed, irradiated with energy rays, and the convex pattern was transferred to the magnetic recording layer.

  The protective layer material was C, and the film was formed to a thickness of 2 nm with an irradiation angle of 80.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 7.2 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, pitch 13 nm)
Example 31 is the same as Example 30 except that a convex pattern is transferred to the magnetic recording layer using a metal fine particle layer having an average particle diameter of 9 nm and a pitch of 13 nm.

  In this example, Au was used for the metal fine particles. Au was prepared and applied in the same manner as in Example 3 to form a fine particle layer on the substrate. Further, a protective layer was formed, irradiated with energy rays, and the convex pattern was transferred to the magnetic recording layer.

  The protective layer material was C, and the film was formed to a thickness of 2 nm with an irradiation angle of 80.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 11.6 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, pitch 8nm)
Example 32 is the same as Example 30 except that the convex pattern is transferred to the magnetic recording layer using a metal fine particle layer having an average particle size of 5.5 nm and a pitch of 8 nm.

  In this example, Au was used for the metal fine particles. Au was prepared and applied in the same manner as in Example 3 to form a fine particle layer on the substrate. Further, a protective layer was formed, irradiated with energy rays, and the convex pattern was transferred to the magnetic recording layer.

  The protective layer material was C, and the film was formed to a thickness of 2 nm with an irradiation angle of 80.

  Thereafter, the convex pattern was transferred to the mask layer and the magnetic recording layer in the same manner as in Example 3, and after removing the mask layer with a solution, the protective layer material was formed obliquely. Finally, a magnetic recording medium having a convex pattern was obtained by forming a perfluoropolyether lubricant film with a thickness of 1.5 nm.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, it was possible to obtain a value of 12.8 dB as the SNR value of the medium.

(C protective layer, metal fine particle lithography, irradiation angle 60 ° → 0 °)
Example 33 is the same as Example 3 except that the angle of oblique film formation of the protective layer material is changed stepwise. In this example, the oblique film forming angle is changed from 60 degrees to 0 degrees.

  In the oblique film formation of the protective layer, first, a 1.3 nm thickness C film is formed at an irradiation angle of 60 degrees, and then an irradiation angle of 0 degrees, that is, a 0.7 nm thickness C film is formed by facing irradiation. A C protective layer having a thickness of 2 nm was formed.

  Thereafter, a perfluoropolyether lubricant film having a thickness of 1.5 nm was formed in the same manner as in Example 3 to obtain a magnetic recording medium having a convex pattern.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. The surface roughness of the medium was smaller than that obtained by forming the protective layer at a single irradiation angle, and the hit of the magnetic head against the medium surface could be reduced. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 10.5 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, irradiation angle 70 ° → 0 °)
Example 34 is the same as Example 3 except that the angle of oblique film formation of the protective layer material is changed stepwise. This example shows an example in which the angle of oblique film formation is changed from 70 degrees to 0 degrees.

In the oblique film formation of the protective layer, first, a 0.9 nm thickness C film is formed at an irradiation angle of 70 degrees, and then an irradiation angle of 0 degrees, that is, a 1.1 nm thickness C film is formed by facing irradiation. A C protective layer having a thickness of 2 nm was formed.

  Thereafter, a perfluoropolyether lubricant film having a thickness of 1.5 nm was formed in the same manner as in Example 3 to obtain a magnetic recording medium having a convex pattern.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. The surface roughness of the medium was smaller than that obtained by forming the protective layer at a single irradiation angle, and the hit of the magnetic head against the medium surface could be reduced. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 10.7 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, irradiation angle 80 ° → 0 °)
Example 35 is the same as Example 3 except that the angle of oblique film formation of the protective layer material is changed stepwise. This example shows an example in which the angle of oblique film formation is changed from 80 degrees to 0 degrees.

  In the oblique film formation of the protective layer, first, a 0.9 nm thickness C film is formed at an irradiation angle of 80 degrees, and then an irradiation angle of 0 degrees, that is, a 1.1 nm thickness C film is formed by facing irradiation. A C protective layer having a thickness of 2 nm was formed.

  Thereafter, a perfluoropolyether lubricant film having a thickness of 1.5 nm was formed in the same manner as in Example 3 to obtain a magnetic recording medium having a convex pattern.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. The surface roughness of the medium was smaller than that obtained by forming the protective layer at a single irradiation angle, and the hit of the magnetic head against the medium surface could be reduced. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 11 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, thin film to thin film)
Examples 36 to 37 are examples in which a protective layer material is previously formed as a thick film by oblique film formation, and a desired protective layer thickness is obtained by performing thinning by etching. The mask layer, the metal fine particle layer, the convex pattern transfer from the metal fine particle layer to the magnetic recording layer, and the mask peeling step are the same as in the third embodiment.

The protective layer material was C, and the film was formed to a thickness of 40 nm by DC sputtering with an irradiation angle of 70 degrees. Subsequently, the C film was thinned by etching. Here, inductively coupled plasma etching with an etchant of O ₂ is applied, the gas pressure is set to 0.1 Pa, the antenna power is set to 40 W, the bias power is set to 40 W, the etching is performed for 47 seconds, and the 2 nm thick C protective layer is formed. Obtained.

  Thereafter, a perfluoropolyether lubricant film having a thickness of 1.5 nm was formed in the same manner as in Example 3 to obtain a magnetic recording medium having a convex pattern.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. At this time, the location dependence of the protective layer material on the medium surface was smaller than the medium obtained by irradiation of the protective layer at a single angle, and a medium having a low convex pattern difference was obtained.

  The surface roughness of the medium was smaller than that obtained by forming the protective layer at a single irradiation angle, and the hit of the magnetic head against the medium surface could be reduced. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 12 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, thin film to thin film)
Example 37 is the same as Example 36 except that the protective layer material formed obliquely is thinned by ion milling.

  The protective layer material was C, and the film was formed to a thickness of 10 nm by DC sputtering using an irradiation angle of 70 degrees. Subsequently, the C film was thinned by etching. Here, an ion milling method using Ar ions was applied. Ion milling was performed at a gas pressure of 0.1 Pa, a gas flow rate of 8 sccm, and an acceleration voltage of 300 V to obtain a 2 nm thick C protective layer.

  Thereafter, a perfluoropolyether lubricant film having a thickness of 1.5 nm was formed in the same manner as in Example 3 to obtain a magnetic recording medium having a convex pattern.

  The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. At this time, the location dependence of the protective layer material on the medium surface was smaller than the medium obtained by irradiation of the protective layer at a single angle, and a medium having a low convex pattern difference was obtained.

  The surface roughness of the medium was smaller than that obtained by forming the protective layer at a single irradiation angle, and the hit of the magnetic head against the medium surface could be reduced. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 11.6 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, SOC film formation after film formation)
In Example 38, a C protective layer was formed by oblique film formation, and a spin-on carbon film was further formed on the C protective layer. The convex pattern formation and the protective layer formation by sputtering in this example are the same as in Example 3.

  First, a C protective layer having a thickness of 1 nm was formed by oblique film formation. Subsequently, a spin-on carbon solution was spin-coated on the medium, and a uniform film was formed to a thickness of 2 nm. In order to remove the solvent in the spin-on carbon film, baking was carried out at 140 ° C. for 5 minutes on a hot plate, and post-treatment was performed.

  Thereafter, a perfluoropolyether lubricant film having a thickness of 1.5 nm was formed in the same manner as in Example 3 to obtain a magnetic recording medium having a convex pattern.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. At this time, since the concave portion of the protective layer material on the medium surface was filled with spin-on carbon, a medium having a lower roughness and a lower convex pattern difference was obtained than the medium obtained by single-angle protective layer irradiation.

The surface roughness of the medium was smaller than that obtained by forming the protective layer at a single irradiation angle, and the hit of the magnetic head against the medium surface could be reduced. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 11 dB could be obtained as the SNR value of the medium.

(C protective layer, metal fine particle lithography, SOC film formation after film formation → thinning)
In Example 38, a C protective layer is formed by oblique film formation, and after a spin-on carbon film is formed on the C protective layer, the film is further thinned by etching. The convex pattern formation and the protective layer formation by sputtering in this example are the same as in Example 3.

First, a C protective layer having a thickness of 2 nm was formed by oblique film formation. Subsequently, a spin-on carbon solution was spin-coated on the medium, and a uniform film was formed to a thickness of 20 nm. In order to remove the solvent in the spin-on carbon film, baking was carried out at 140 ° C. for 5 minutes on a hot plate, and post-treatment was performed. Subsequently, in order to make the thickened spin-on carbon into a thin film, etching using O ₂ gas as an etchant was performed. Etching is inductively coupled plasma reactive ion etching, gas pressure is 0.1 Pa, antenna power is 40 W, bias power is 40 W, and the spin-on carbon film is thinned by performing etching for 15 seconds, and a medium having a total protective layer thickness of 3 nm is formed. Obtained.

  Thereafter, a perfluoropolyether lubricant film having a thickness of 1.5 nm was formed in the same manner as in Example 3 to obtain a magnetic recording medium having a convex pattern.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the flying height of 10 nm, which is a standard necessary for performing the read / write evaluation of the medium, could be passed. At this time, since the concave portion of the protective layer material on the medium surface was filled with spin-on carbon, a medium having a lower roughness and a lower convex pattern difference was obtained than the medium obtained by single-angle protective layer irradiation.

The surface roughness of the medium was smaller than that obtained by forming the protective layer at a single irradiation angle, and the hit of the magnetic head against the medium surface could be reduced. Further, the signal-to-noise ratio of the medium was measured using a spin stand. As a result, a value of 10.8 dB could be obtained as the SNR value of the medium.

Comparative Example 1

(C protective layer, metal fine particle lithography, protective layer thickness 6 nm)
Comparative Example 1 is an example in which oblique film formation is performed to form a 6 nm thick protective layer. The magnetic recording layer, the mask layer, the metal fine particle layer, and the convex pattern transfer and peeling process on them are the same as in Example 3.

  The protective layer was C, and the film was deposited with a thickness of 6 nm by DC sputtering with an irradiation angle of 70 degrees.

  Thereafter, a perfluoropolyether lubricant film having a thickness of 1.5 nm was formed in the same manner as in Example 3 to obtain a magnetic recording medium having a convex pattern.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, as the thickness of the protective layer increases, the hitting of the convex pattern on the medium surface with respect to the magnetic head increases remarkably, and the 10 nm flying height, which is a standard necessary for performing the read / write evaluation of the medium, is passed. could not.

Comparative Example 2

(C protective layer, metal fine particle lithography, protective layer thickness 2 nm, irradiation angle 0 degree)
Comparative Example 2 is an example in which a protective layer having a thickness of 2 nm is formed by performing film formation with an irradiation angle of 0 degree, that is, perpendicular incidence. The magnetic recording layer, the mask layer, the metal fine particle layer, and the convex pattern transfer and peeling process on them are the same as in Example 3.

  The protective layer was C, and the film was deposited with a thickness of 2 nm by DC sputtering with an irradiation angle of 0 degree.

  Thereafter, a perfluoropolyether lubricant film having a thickness of 1.5 nm was formed in the same manner as in Example 3 to obtain a magnetic recording medium having a convex pattern.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, as the convex pattern of the protective layer is enhanced, the hit of the convex pattern on the medium surface with respect to the magnetic head increases remarkably, and the 10 nm flying height, which is a standard necessary for performing the read / write evaluation of the medium, is passed. I couldn't.

Comparative Example 3

(C protective layer, metal fine particle lithography, protective layer thickness 2 nm, irradiation angle 20 degrees)
Comparative Example 3 is an example in which an oblique film formation with an irradiation angle of 20 degrees is performed to form a protective layer having a thickness of 2 nm. The magnetic recording layer, the mask layer, the metal fine particle layer, and the convex pattern transfer and peeling process on them are the same as in Example 3.

  The protective layer was C, and the film was deposited with a thickness of 6 nm by DC sputtering with an irradiation angle of 70 degrees.

  Thereafter, a perfluoropolyether lubricant film having a thickness of 1.5 nm was formed in the same manner as in Example 3 to obtain a magnetic recording medium having a convex pattern.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, as the convex pattern of the protective layer is enhanced, the hit of the convex pattern on the medium surface with respect to the magnetic head increases remarkably, and the 10 nm flying height, which is a standard necessary for performing the read / write evaluation of the medium, is passed. I couldn't.

Comparative Example 4

(C protective layer, metal fine particle lithography, protective layer thickness 2 nm, irradiation angle 85 degrees)
Comparative Example 4 is an example in which a 2 nm thick protective layer is formed by performing oblique film formation with an irradiation angle of 85 degrees. The magnetic recording layer, the mask layer, the metal fine particle layer, and the convex pattern transfer and peeling process on them are the same as in Example 3.

  The protective layer was C, and the film was deposited with a thickness of 6 nm by DC sputtering with an irradiation angle of 85 degrees.

  Thereafter, a perfluoropolyether lubricant film having a thickness of 1.5 nm was formed in the same manner as in Example 3 to obtain a magnetic recording medium having a convex pattern.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, as the convex pattern of the protective layer is enhanced, the hit of the convex pattern on the medium surface with respect to the magnetic head increases remarkably, and the 10 nm flying height, which is a standard necessary for performing the read / write evaluation of the medium, is passed. I couldn't.

Comparative Example 5

(C protective layer, metal fine particle lithography, protective layer thickness 2 nm, irradiation angle 0 ° → 70 °)
Comparative Example 5 is a case where the oblique film formation angle in the protective layer film formation is changed stepwise, but is an example in which the order of the irradiation angles set in Examples 33 to 35 is changed. The magnetic recording layer, the mask layer, the metal fine particle layer, and the convex pattern transfer and peeling process on them are the same as in Example 3.

  The protective layer was C. First, a film was formed with an irradiation angle of 0 degree, that is, with a thickness of 2 nm by normal incidence, and then an oblique film formation with an irradiation angle of 70 degrees was performed to obtain a protective layer with a total thickness of 3 nm. .

  Thereafter, a perfluoropolyether lubricant film having a thickness of 1.5 nm was formed in the same manner as in Example 3 to obtain a magnetic recording medium having a convex pattern.

The flying height of the head with respect to the obtained magnetic recording medium was measured with a glide height tester, and the flying characteristics were evaluated. As a result, the convex pattern of the protective layer generated by the first perpendicular incidence is enhanced by oblique film formation, and the hit of the convex pattern on the medium surface with respect to the magnetic head is markedly increased, and the read / write evaluation of the medium is performed. Therefore, it was not possible to pass the flying height of 10 nm which is a necessary standard.

The results of the above Examples and Comparative Examples are shown in Table 1 and Table 2 below.

  FIG. 21 shows the irradiation angle of the film forming material and the film thickness of the formed protective film in the oblique film formation of the protective film for Examples 1, 25, 26, 27, and 30 and Comparative Examples 2, 3, and 4. The graph showing the relationship with is shown.

Table 3 below shows the measurement results.

  As shown in the graph 401 and Table 1, the irradiation angle is preferably 40 to 80 °. When the irradiation angle is 40 to 80 °, the thickness of the protective film is 2 to 3 nm. In this case, the protective layer material between the dots is formed in a bridge shape, and a gap is generated between the convex and convex patterns. Therefore, it was found that if the protective film is formed in this irradiation range, the flatness of the uneven pattern can be improved and the flying characteristics of the head can be improved.

  FIG. 22 shows an example of a graph showing the relationship between the convex portion height of the magnetic recording layer and the protective layer material concentration in Examples 1, 2, 3, 4 and Comparative Examples 2, 3, 4, 5.

Table 4 below shows the measurement results.

  As shown in the graph 402 and Table 2, the height of the convex portion of the magnetic recording layer is preferably 1 nm to 10 nm. This is because if the thickness is less than 1 nm, in addition to the deterioration of the thermal fluctuation resistance of the magnetic recording layer, there is almost no flattening effect even if a protective film is formed by oblique irradiation. Moreover, it turned out that it is because manufacture becomes difficult when it exceeds 10 nm. Since the main component concentration of the protective layer material on the surface of the magnetic recording layer increases sharply when the unevenness difference is 1 nm or more, in order to form a flat protective layer with a space between the protrusions and protrusions, the unevenness of the magnetic recording layer Is more preferably 1 nm or more. Furthermore, it was found that the inclination of the change in the main component concentration of the protective layer material with respect to the height of the convex portion tends to increase as the pattern pitch decreases.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Magnetic recording layer, 3 ... Mask layer, 4 ... Metal fine particle, 5 ... 1st solvent, 6 ... Metal fine particle coating layer, 7 ... 2nd solvent, 8 ... Metal fine particle film, 9 ... Protection Layer, 18 ... gap, 26 ... magnetic layer, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110 ... magnetic recording medium, 200, 201, 202 ... stamper

Embodiments described herein relate generally to a magnetic recording medium and a magnetic recording / reproducing apparatus .

According to an embodiment, the substrate,
A magnetic recording layer comprising a plurality of convex magnetic layers formed on the substrate;
Magnetic recording layer formed on the protective film, and viewed including the said protective film, and the substrate surface, a gap provided in the region surrounded by the side walls of the magnetic layers,
The height of the magnetic layer is larger than the thickness of the protective film when the distance between the adjacent magnetic layers is the longest,
The thickness of the protective film is t3 when the distance between the adjacent magnetic layers is the longest, t2 when the distance between the adjacent magnetic layers is the shortest, and the magnetic film Provided is a magnetic recording medium characterized by satisfying t1 ≦ t2 ≦ t3, where t1 is the thickness of the protective film on the layer .

Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.
Hereinafter, the invention described in the scope of claims of the present application will be appended.
[1] substrate,
A magnetic recording layer comprising a plurality of convex magnetic layers formed on the substrate;
A protective film formed on the magnetic recording layer; and
A magnetic recording medium comprising a gap provided in a region surrounded by the protective film, the substrate surface, and a side wall of each magnetic layer.
[2] The magnetic recording medium according to [1], wherein the pitch between the centers of adjacent magnetic layers is 20 nm or less.
[3] The magnetic recording medium according to [1] or 2, wherein a height of the magnetic layer is higher than a height of the protective film.
[4] The protective film and the gap are each formed by obliquely forming a protective film material on the convex magnetic layer, according to any one of [1] to [3] The magnetic recording medium described.
[5] The oblique film formation is performed at an angle of 40 ° to 80 °, where the direction perpendicular to the substrate is 0 °, according to any one of [1] to [4]. Magnetic recording medium.
[6] The thickness of the protective film is t3 when the distance between adjacent magnetic layers is the longest, and t2 when the distance between adjacent magnetic layers is the longest. The magnetic recording medium according to any one of [1] to [5], wherein t3 ≦ t2 ≦ t1 is satisfied, where t1 is a thickness of the protective film on the magnetic layer.
[7] The magnetic recording medium according to any one of [1] to [6], wherein each of the magnetic layers has a shape of a cylinder, a prism, a cone, or a pyramid.
[8] The main component of the protective film provided between the magnetic layers has a concentration distribution in the thickness direction, and the protective film provided on the magnetic layer is more than the protective film provided between the magnetic layers. The magnetic recording medium according to any one of [1] to [7], wherein the main component is a high concentration.
[9] The magnetic recording medium according to any one of [1] to [8], wherein the protective film material is made of a nonmagnetic material.
[10] A magnetic recording / reproducing apparatus comprising the magnetic recording medium according to any one of [1] to [9] and a recording / reproducing head.
[11] forming a magnetic recording layer on the substrate;
Patterning the magnetic recording layer to form a magnetic recording layer comprising a plurality of convex magnetic layers;
By forming a protective film material obliquely on the convex pattern of the magnetic recording layer, a protective film is formed on the magnetic recording layer, and the protective film, the substrate surface, and the side walls of each magnetic layer And a step of providing a gap in a region surrounded by the magnetic recording medium.
[12] The step of patterning the magnetic recording layer includes:
Forming a mask layer on the magnetic recording layer;
Forming a resist layer on the mask layer;
Providing a convex pattern by patterning the resist layer;
Transferring the convex pattern to the mask layer;
Transferring the convex pattern to the magnetic recording layer and forming a magnetic recording layer comprising a plurality of convex magnetic layers;
The method according to [11], further comprising a step of removing the mask layer from the magnetic recording layer.
[13] The step of patterning the magnetic recording layer includes:
Forming a mask layer on the magnetic recording layer;
Forming a metal fine particle layer comprising a plurality of metal fine particles on the mask layer;
Transferring a convex pattern constituted by the metal fine particle layer to the mask layer;
Transferring the convex pattern to the magnetic recording layer and forming a magnetic recording layer comprising a plurality of convex magnetic layers;
The method according to [11], further comprising a step of removing the mask layer from the magnetic recording layer.
[14] The plurality of metal fine particles are covered with a protective material,
A step of forming an overcoat layer on the surface of the metal fine particle layer before the step of transferring the convex pattern constituted by the metal fine particle layer to the mask layer;
The method according to [13], further comprising a step of deactivating the protective material by irradiating the metal fine particle layer with energy rays through the overcoat layer.
[15] The oblique film formation is performed at an angle of 40 ° to 80 ° when the direction perpendicular to the substrate is 0 ° with respect to the substrate. 2. The method according to item 1.

Claims (15)

substrate,
A magnetic recording layer comprising a plurality of convex magnetic layers formed on the substrate;
A magnetic recording medium comprising: a protective film formed on the magnetic recording layer; and a void provided in a region surrounded by the protective film, the substrate surface, and a side wall of each magnetic layer.   The magnetic recording medium according to claim 1, wherein the pitch between the centers of adjacent magnetic layers is 20 nm or less.   The magnetic recording medium according to claim 1, wherein a height of the magnetic layer is higher than a height of the protective film.   4. The magnetic recording medium according to claim 1, wherein the protective film and the gap are each formed by forming a protective film material obliquely on the convex magnetic layer. 5. .   5. The magnetic recording medium according to claim 1, wherein the oblique film formation is performed at an angle of 40 ° to 80 ° when a direction perpendicular to the substrate is set to 0 °.   The thickness of the protective film is t3 when the distance between the adjacent magnetic layers is the longest, t2 when the distance between the adjacent magnetic layers is the longest, and the thickness of the protective film 6. The magnetic recording medium according to claim 1, wherein t3 ≦ t2 ≦ t1 is satisfied, where t1 is a thickness of the protective film on the layer.   The magnetic recording medium according to claim 1, wherein each of the magnetic layers has a shape of a cylinder, a prism, a cone, or a pyramid.   The main component of the protective film provided between the magnetic layers has a concentration distribution in the thickness direction, and the protective film provided on the magnetic layer is more than the protective film provided between the magnetic layers. The magnetic recording medium according to claim 1, wherein the main component is a high concentration.   The magnetic recording medium according to claim 1, wherein the protective film material is made of a nonmagnetic material.   A magnetic recording / reproducing apparatus comprising the magnetic recording medium according to claim 1 and a recording / reproducing head. Forming a magnetic recording layer on the substrate;
By patterning the magnetic recording layer to form a magnetic recording layer composed of a plurality of convex magnetic layers, and forming a protective film material obliquely on the convex pattern of the magnetic recording layer, A step of forming a protective film on the recording layer, and providing a gap in a region surrounded by the protective film, the substrate surface, and the side wall of each magnetic layer. Production method. The step of patterning the magnetic recording layer includes:
Forming a mask layer on the magnetic recording layer;
Forming a resist layer on the mask layer;
Providing a convex pattern by patterning the resist layer;
Transferring the convex pattern to the mask layer;
Transferring the convex pattern to the magnetic recording layer and forming a magnetic recording layer comprising a plurality of convex magnetic layers;
The method according to claim 11, further comprising the step of removing the mask layer from the magnetic recording layer. The step of patterning the magnetic recording layer includes:
Forming a mask layer on the magnetic recording layer;
Forming a metal fine particle layer comprising a plurality of metal fine particles on the mask layer;
Transferring a convex pattern constituted by the metal fine particle layer to the mask layer;
Transferring the convex pattern to the magnetic recording layer and forming a magnetic recording layer comprising a plurality of convex magnetic layers;
The method of claim 11, comprising removing the mask layer from the magnetic recording layer. The plurality of metal fine particles are covered with a protective material,
A step of forming an overcoat layer on the surface of the metal fine particle layer before the step of transferring the convex pattern constituted by the metal fine particle layer to the mask layer;
The method according to claim 13, further comprising a step of deactivating the protective material by irradiating the metal fine particle layer with energy rays through the overcoat layer.   The oblique film formation is performed at an angle of 40 ° to 80 °, where the direction perpendicular to the substrate is 0 ° with respect to the substrate. Method.

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