JP5345562B2 - Method for manufacturing magnetic recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a magnetic recording medium at a high yield while precisely forming a pattern shape of a magnetic layer. <P>SOLUTION: The method for manufacturing a magnetic recording medium forms a magnetic layer 2 on a nonmagnetic substrate 1, and thereafter partially injects ion into the magnetic layer 2 so as to reform the magnetic properties of the ion-injected place 8 of the magnetic layer 2 to form magnetically separated magnetic recording patterns. A reusable mask material 10 is disposed over the magnetic layer 2 with a gap from the magnetic layer 2, the mask material 10 is irradiated with ion from the top thereof. Through the concaves 10a of a concave/convex pattern corresponding to the magnetic patterns MP formed on the surface of the mask material 10, the ion is partially injected to the magnetic layer 2 located below. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

The present invention relates to the production how the magnetic recording medium used in a hard disk drive (HDD) or the like.

  In recent years, the application range of magnetic recording devices such as magnetic disk devices, flexible disk devices, and magnetic tape devices has been remarkably increased, and the importance has increased, and the recording density of magnetic recording media used in these devices has been significantly improved. Is being planned. In particular, since the introduction of MR heads and PRML technology, the increase in surface recording density has become even more intense. In recent years, GMR heads, TMR heads, etc. have been introduced and have continued to increase at a rate of about 1.5 times a year. ing.

  These magnetic recording media are required to achieve higher recording densities in the future. For this reason, it is required to achieve a high coercivity of the magnetic layer, a high signal-to-noise ratio (SNR), and high resolution. In recent years, efforts have been made to increase the surface recording density by increasing the track density as well as improving the linear recording density.

  In the latest magnetic recording apparatus, the track density has reached 110 kTPI. However, as the track density is increased, magnetic recording information between adjacent tracks interferes with each other, so that a problem occurs that the magnetization transition region in the boundary region becomes a noise source and the SNR is impaired. This directly leads to a deterioration of the bit error rate, which is an obstacle to improving the recording density.

  In order to increase the surface recording density, it is necessary to make the size of each recording bit on the magnetic recording medium finer and ensure as much saturation magnetization and magnetic film thickness as possible for each recording bit. On the other hand, however, when the recording bit is miniaturized, the minimum magnetization volume per bit is reduced, so that there is a problem that the recording data is lost due to magnetization reversal due to thermal fluctuation.

  Further, as the track density is increased, the distance between tracks approaches each other. For this reason, a magnetic recording apparatus requires a highly accurate track servo technique, and at the same time, a method is generally used in which recording is performed widely and reproduction is performed narrower than during recording. This makes it possible to minimize the influence from adjacent tracks, but on the other hand, it becomes difficult to obtain a sufficient reproduction output. Therefore, there is a problem that it is difficult to ensure a sufficient SNR.

  As one of the methods for achieving such problems of thermal fluctuation, ensuring SNR, and ensuring sufficient output, by forming irregularities along the tracks on the recording medium surface and physically separating the recording tracks from each other Attempts have been made to increase track density. Such a technique is generally called a discrete track method, and a magnetic recording medium manufactured by the technique is called a discrete track medium. There is also an attempt to manufacture a so-called patterned medium in which the data area in the same track is further divided.

As an example of a discrete track medium, a magnetic recording medium is known in which a magnetic layer is formed on a nonmagnetic substrate having a concavo-convex pattern formed on the surface, and a physically separated magnetic recording track and a servo signal pattern are formed. . As a method for manufacturing such a discrete track type magnetic recording medium, a method of processing a continuous magnetic layer formed on a substrate into a magnetic recording track pattern or a bit pattern using a nanoimprint method has been proposed. .
The nanoimprint method is a method of transferring a concavo-convex pattern to a material to be transferred by pressing the mold on which the concavo-convex pattern to be transferred is pressed against the material to be transferred and curing the material to be transferred while irradiating light or applying heat. Yes (see Patent Document 1).

  A method for manufacturing a discrete track medium includes a method of forming a track by forming a magnetic recording medium consisting of several continuous thin films, and forming a track on the substrate surface in advance, or a thin film layer for forming a track. There is a method of forming a thin film of a magnetic recording medium after forming a concavo-convex pattern (see Patent Documents 2 and 3).

  Of these, the former method is called a magnetic layer processing type. However, in the case of this method, since the surface is physically processed after the medium is formed, there is a drawback that the medium is easily contaminated in the manufacturing process and the manufacturing process becomes very complicated. On the other hand, the latter method is called an embossing mold. In this method, although the medium is hardly contaminated during the manufacturing process, the uneven shape formed on the substrate is formed on the film formed thereon. Will be taken over. Therefore, there is a problem that the flying posture and the flying height of the recording / reproducing head that performs recording / reproducing while flying on the medium are not stable.

  Also, the magnetic track area of the discrete track medium is formed by injecting ions such as nitrogen and oxygen into a previously formed magnetic layer or by irradiating a laser to change the magnetic characteristics of the portion. A method is disclosed (see Patent Documents 4 to 6).

JP 2004-164692 JP JP 2004-178793 JP JP 2004-178794 A JP-A-5-205257 JP 2006-209952 A JP 2006-309841 A

  Incidentally, high smoothness on the surface of the magnetic recording medium is required for the magnetic head to fly and run in a stable state on the surface of the magnetic recording medium. For example, in the so-called discrete track media and patterned media having magnetically separated magnetic recording patterns, the following manufacturing processes are employed. A mask layer is provided on the surface of the magnetic layer, and the mask layer is patterned according to the magnetic recording pattern. A method of forming a magnetic recording pattern on the magnetic layer by physically processing the magnetic layer using the mask layer or performing ion implantation is known. This manufacturing method will be described below with reference to FIGS.

  The specific steps of such a manufacturing method are, for example, a step (step a) of forming the magnetic layer 102 on the nonmagnetic substrate 101 shown in FIG. 1A and a step on the magnetic layer 102 shown in FIG. The step of forming the mask layer 103 (step b), the step of forming the resist layer 104 on the mask layer 103 shown in FIG. 1C (step c), and the stamp 105 shown in FIG. Forming a resist recess 108 in the layer 104, patterning the resist layer 104 into a shape corresponding to the magnetic recording pattern (step d), a resist layer 104 in a region corresponding to the magnetic recording pattern shown in FIG. A step of removing the mask layer 103 to expose the magnetic layer 102 (step e), and ion implantation is performed on the exposed region 107 of the magnetic layer 102 shown in FIG. Magnetism And step (step f) of forming a discrete magnetic recording pattern, a step of removing the resist layer 104 and mask layer 103 shown in FIG. 1 (g) (step g), is schematically composed.

  The reason why the mask layer 103 is provided in the above step c is that when ion implantation is performed in the step f, the resist layer 104 alone has a poor shielding property against implanted ions. Further, in the step d, photolithography may be used. Further, the processing and removal of the resist layer 104 and the mask layer 103 in the steps e and g may be performed by dry etching.

As described above, the production of patterned media is performed by many processes. For this reason, there has been a problem that as the processes become more complicated, the pattern tends to become unclear.
That is, in the above process, the pattern of the master used for photolithography and nanoimprint is the clearest, and the pattern of the process d to which the pattern is transferred is less sharp than the pattern of the master. Further, in the next step e, when the mask layer 103 is removed, the edge portion of the pattern becomes round, so that the sharpness of the pattern is lowered. Then, by patterning the magnetic layer 102 in step F using the pattern, the sharpness of the pattern is further reduced.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method of manufacturing a magnetic recording medium that can form a clear magnetic recording pattern on the magnetic layer 102 by a simple method.

In order to solve the above-mentioned problems, the inventors of the present application have intensively studied to arrive at the present invention. That is, the present invention relates to the following.
[1] After a magnetic layer is formed on a nonmagnetic substrate, ions are partially implanted into the magnetic layer, thereby modifying the magnetic properties of the magnetic layer where the ions are implanted to magnetically A method of manufacturing a magnetic recording medium for forming separated magnetic recording patterns, wherein a mask material that can be used repeatedly is disposed on the magnetic layer while maintaining a gap from the magnetic layer, and Ion irradiation is performed, and ions are partially implanted into the magnetic layer below the concave portion of the concave / convex pattern corresponding to the magnetic recording pattern formed on the surface of the mask material. from it, a thickness ranging 20nm~50nm in the recess of the uneven pattern, Turkey used as thickness at the convex portion of the concavo-convex pattern in the range of 80nm~500nm A method of manufacturing a magnetic recording medium characterized by the above .
[2 ] The method for manufacturing a magnetic recording medium according to [1 ], wherein, in the ion irradiation step, an interval between the magnetic layer and the mask material is 1 μm or less.
[ 3 ] The method for producing a magnetic recording medium according to [1] or [2] , wherein the ions include one or more selected from the group consisting of nitrogen, oxygen, helium, and neon.
[ 4 ] The method for manufacturing a magnetic recording medium according to any one of [1] to [ 3 ], further comprising a step of forming a protective layer on the magnetic layer after removing the mask material. .

According to the present invention, the magnetic layer is directly patterned by the mask material that becomes the master disk of the magnetic recording pattern. Therefore, a magnetic recording medium having a clear magnetic recording pattern can be manufactured. This makes it possible to increase the density of the magnetic recording pattern and provide a magnetic recording / reproducing apparatus with a high recording density.
Further, according to the present invention, the manufacturing process does not involve a mask layer or resist layer forming process or a processing process, and therefore, the manufacturing process can be significantly simplified as compared with the conventional manufacturing method. Further, the mask material of the present invention can be used repeatedly for the production of a plurality of magnetic recording media. Therefore, the manufacturing cost of the magnetic recording medium can be significantly reduced.

It is a schematic diagram which shows the manufacturing method of the conventional magnetic recording medium. It is a schematic diagram which shows the manufacturing method of the magnetic recording medium of this invention. 1 is a schematic perspective view showing a hard disk drive as an example of a magnetic recording / reproducing apparatus of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. . In addition, the materials, dimensions, and the like exemplified in the following description are examples, and the present invention is not limited to them, and can be appropriately changed and implemented without changing the gist thereof.

First, a method for manufacturing a magnetic recording medium to which the present invention is applied will be described with reference to FIG.
The present invention relates to a method of manufacturing a magnetic recording medium having magnetically separated magnetic recording patterns. For example, as shown in FIGS. 2 (a) to 2 (d), a magnetic layer is formed on a nonmagnetic substrate 1. And a mask material 10 patterned in a shape corresponding to the magnetic recording pattern MP on the magnetic layer 2, and disposed on the magnetic layer 2 while maintaining a distance from the magnetic layer 2. A step (step b), a step of irradiating ions from above the mask material 10 to form the magnetic recording pattern MP on the magnetic layer 2 (step c), and a step of forming the protective layer 9 on the magnetic layer 2 (step) d) and a step (step e) (not shown) for forming a lubricant layer (not shown) on the protective layer 9. Hereinafter, each step will be described in detail with reference to FIGS. 2 (a) to 2 (d).

<Step a>
First, as shown in FIG. 2A, a magnetic layer 2 is formed on a nonmagnetic substrate 1.
First, the nonmagnetic substrate 1 is prepared. In the present embodiment, as the nonmagnetic substrate 1, an Al alloy substrate such as an Al-Mg alloy, which is mainly composed of Al, ordinary soda glass, aluminosilicate glass, crystallized glass, silicon, titanium, ceramics, Any nonmagnetic substrate such as a substrate made of various resins can be used. Among them, it is preferable to use a glass substrate such as an Al alloy substrate or crystallized glass, or a silicon substrate. Moreover, the average surface roughness (Ra) of these substrates is preferably 1 nm or less, more preferably 0.5 nm or less, and particularly preferably 0.1 nm or less.

Next, the magnetic layer 2 made of a thin film of an alloy containing Co as a main component is formed by using, for example, a sputtering method so as to cover the nonmagnetic substrate 1.
At this time, the thickness of the magnetic layer 2 is preferably 3 nm or more and 20 nm or less, and more preferably 5 nm or more and 15 nm or less.
The magnetic layer 2 needs to have a certain film thickness in order to obtain a certain output during reproduction. Also, various parameters representing the recording / reproducing characteristics are usually deteriorated as the output increases. Therefore, it is necessary to form the magnetic layer 2 with an optimum film thickness so that sufficient head input / output can be obtained in accordance with the type of magnetic alloy used and the laminated structure.

  The magnetic layer 2 may be formed by either an in-plane magnetic layer or a perpendicular magnetic layer, but a perpendicular magnetic layer is preferable to achieve a higher recording density. When the magnetic recording medium is used for an in-plane magnetic recording medium, the magnetic layer 2 may be formed with a laminated structure including a nonmagnetic CrMo underlayer and a ferromagnetic CoCrPtTa magnetic layer.

When the magnetic recording medium is used for a perpendicular magnetic recording medium, for example, soft magnetic FeCo alloys (FeCoB, FeCoSiB, FeCoZr, FeCoZrB, FeCoZrBCu, etc.), FeTa alloys (FeTaN, FeTaC, etc.), Co alloys (CoTaZr, CoZrNB) , CoB, etc.), an orientation control film such as Pt, Pd, NiCr, NiFeCr, an intermediate film such as Ru, and a 60Co-15Cr-15Pt alloy or 70Co-5Cr-15Pt-10SiO ₂ alloy. Can be used as the magnetic layer 2.

<Process b>
The step b further includes a mask material 10 preparation step and a step of arranging the mask material 10 on the magnetic layer 2 while maintaining a distance from the magnetic layer 2. The mask material 10 is repeatedly used for manufacturing a plurality of magnetic recording media.

(Mask material 10 preparation process)
First, as shown in FIG. 2B, a mask material 10 made of, for example, quartz is prepared. Other materials such as Ni, Ti, V, Nb, Mo, Ta, and W can be used as the material of the mask material 10, but it is particularly desirable to use quartz. This is because, in an ion implantation step (step c), which will be described later, when the mask material 10 is irradiated with ions, the ions need to pass through the recess 10a.

In addition, as a material of the mask material 10, a metal may be inappropriate due to insufficient ion permeability. Further, when a metal is used as the material of the mask material 10, it is necessary to reduce the thickness of the recess 10a in order to transmit ions. For this reason, the durability of the mask material 10 is lowered, which may be inappropriate for repeated use.
On the other hand, the thinned quartz can transmit ions and has high permeability. In addition, since fine processing can be performed by wet etching or dry etching, the magnetic recording pattern MP is easily formed as a concavo-convex pattern (concave portion 10a and convex portion 10b). Therefore, quartz is particularly suitable as a material for the mask material 10.

  On the surface of the mask material 10, the magnetic recording pattern MP is configured as an uneven pattern (concave portion 10 a and convex portion 10 b). It is actually difficult to configure the magnetic recording pattern MP of the mask material 10 only by the hole portion, and it is necessary to configure it by an uneven pattern.

  That is, the magnetic recording pattern MP of the present embodiment is a so-called bit patterned medium in which the magnetic recording pattern is arranged with a certain regularity for each bit, a discrete track medium in which the magnetic recording pattern is arranged in a track shape, In addition, servo signal patterns and the like are included. For this reason, the magnetic recording pattern MP is fine and complicated, and it is difficult to form the magnetic recording pattern MP only by the holes. Therefore, the mask material 10 of the present embodiment does not have a hole portion, and the magnetic recording pattern MP is configured by the uneven pattern formed on the surface thereof.

The thickness d of the concave portion 10a of the mask material 10 is preferably in the range of 20 to 50 nm, and the thickness e of the convex portion 10b is preferably in the range of 80 to 500 nm.
By setting the thickness d of the concave portion 10a within the range of 20 to 50 nm, ions can permeate the concave portion 10a in an ion implantation step (step c) described later. Therefore, ions can be implanted into the magnetic layer 2 through the recess 10 a of the mask material 10.

  In particular, in a later-described ion implantation step (step c), when a substance having a small atomic radius such as nitrogen, oxygen, helium, or neon is used as the implanted ions, the thickness d of the recess 10a is set within a range of 20 to 50 nm. It is particularly preferred. By setting the thickness d of the recess 10a within this range, these ions permeate the recess 10a with high efficiency. Therefore, ion implantation can be effectively performed on the magnetic layer 2 and a clear magnetic recording pattern MP can be formed.

On the other hand, when the thickness d of the concave portion 10a is thinner than 20 nm, the concave portion 10a is easily broken due to damage caused by ion implantation. Moreover, since the durability of the mask material 10 is reduced, the number of times the mask material 10 is repeatedly used is reduced.
In addition, when the thickness d of the recess 10a is greater than 50 nm, the ion permeability in the recess 10a is reduced, so that the patterning of the magnetic layer 2 becomes difficult. Further, since ions are easily scattered in the recess 10a, the magnetic recording pattern MP transferred to the magnetic layer 2 becomes unclear.

  Further, the thickness e of the convex portion 10b of the mask material 10 is preferably as thick as possible from the viewpoint of durability, but in reality, it is preferably within the range of 80 nm to 500 nm because of its workability. When the convex part 10b becomes thicker than 500 nm, the processing time of the concave part 10a becomes long. As a result, the uneven pattern of the mask material 10 tends to be unclear and the productivity is lowered.

(Process of disposing the mask material 10 on the magnetic layer 2)
Next, as shown in FIG. 2B, the mask material 10 with the concavo-convex pattern facing upward is disposed on the magnetic layer 2 while maintaining a gap from the magnetic layer 2.
At this time, the magnetic layer 2 and the mask material 10 are preferably kept at a distance so as not to contact each other, and the distance is preferably 1 μm or less. Further, it is preferable that this interval is as small as possible. At this time, if the distance between the magnetic layer 2 and the mask material 10 is greater than 1 μm, the transfer pattern to the magnetic layer 2 becomes unclear. Further, when the magnetic layer 2 and the mask material 10 come into contact with each other, the magnetic layer 2 and the mask material 10 are damaged, and the magnetic film 2 and the like adhere to the mask material 10. Therefore, the mask material 10 cannot be repeatedly used, which is not preferable.

<Process c>
Next, as shown in FIG. 2C, ion irradiation is performed from above the mask material 10 while the mask material 10 is disposed on the magnetic layer 2. As a result, ions pass through the recess 10a and are injected into the portion of the magnetic layer 2 below the recess 10a. As a result, the demagnetized region 8 is formed in the portion of the magnetic layer 2 below the recess 10a. At this time, since the convex portion 10b is formed with a thickness that does not allow ions to pass therethrough, the portion of the magnetic layer 2 below the convex portion 10b is not modified.
The modification of the magnetic layer 2 in the present embodiment is not limited to the method of demagnetizing a part of the magnetic layer 2 and magnetically separating the magnetic layer 2, but a method of partially reducing the coercive force, the residual magnetization, etc. Alternatively, the crystal structure of the magnetic layer 2 may be modified. For example, by partially amorphizing the magnetic layer 2, it is possible to form a location where the magnetic recording track and the servo signal pattern portion are magnetically separated.

  Amorphization of the magnetic layer 2 is performed by making the atomic arrangement of the magnetic layer 2 an irregular atomic arrangement having no long-range order. Specifically, the irregular atomic arrangement having no long-range order indicates a state in which microcrystal grains of less than 2 nm are randomly arranged. Such an irregular atomic arrangement can be confirmed by an analytical method such as X-ray diffraction or electron beam diffraction. According to such analysis, when a peak representing a crystal plane is not recognized and only a halo is recognized, the atomic arrangement is in an irregular state.

  In the modification of the magnetic layer 2 of this embodiment, the magnetization amount of the non-magnetized region 8 is preferably 75% or less of the magnetic layer 2 and more preferably 50% or less. The coercive force is preferably 50% or less of the magnetic layer 2 and more preferably 20% or less.

As a result, the non-magnetized region 8 is formed on the surface of the magnetic layer 2 below the recess 10a, and the surface of the magnetic layer 2 is magnetically separated by the non-magnetized region 8.
As described above, the magnetic recording pattern MP corresponding to the concave / convex pattern (the concave portion 10a and the convex portion 10b) of the mask material 10 is formed on the magnetic layer 2. Thereafter, the mask material 10 is removed from the magnetic layer 2.

Here, the magnetic recording pattern MP indicates a state in which the magnetic layer 2 is magnetically separated by the non-magnetized region 8 when the magnetic recording medium is viewed from the surface side. That is, if the magnetic layer 2 is separated by the magnetized region 8 when viewed from the surface side, the object of the present invention can be achieved even if it is not separated at the bottom of the magnetic layer 2. Therefore, in the present embodiment, the magnetic recording pattern MP is that in which the surface of the magnetic layer 2 is divided by the non-magnetized region 8.
Thereby, the magnetic layer 2 has a configuration in which the magnetic recording pattern MP, the intermediate layer and the soft magnetic layer (not shown) are formed from above.

<Process d>
Next, as shown in FIG. 2D, a protective layer 9 is formed so as to cover the magnetic layer 2. The protective layer 9 is generally formed by forming a thin film of Diamond Like Carbon using P-CVD or the like, but the method is not limited to this and is not particularly limited.
Examples of the protective layer 9 include carbonaceous layers such as carbon (C), hydrogenated carbon (H _x C), nitrogenated carbon (CN), amorphous carbon, silicon carbide (SiC), SiO ₂ , Zr ₂ O ₃ , A commonly used protective layer material such as TiN can be used. The protective layer 9 may be composed of two or more layers.

  The protective layer 9 needs to be formed with a film thickness of less than 10 nm. This is because if the thickness of the protective layer 9 exceeds 10 nm, the distance between the head of the magnetic recording / reproducing apparatus, which will be described later, and the magnetic layer 2 increases, and the input / output signal cannot be obtained with sufficient strength.

  In the present embodiment, the protective layer 9 is preferably formed after the non-magnetized region 8 is formed. Although ion implantation into the magnetic layer 2 can be performed from above the protective layer 9, in this case, since the implanted ions are scattered by the protective layer 9, the definition of the magnetic recording pattern MP is lowered. Further, the protective layer 9 may be damaged by the ion implantation, and the function as the protective layer 9 of the magnetic recording medium may not be performed.

<Process e>
After that, it is preferable to form a lubricating layer (not shown) with a thickness of 1 to 4 nm so as to cover the protective layer 9. Examples of the lubricant used for the lubricating layer include a fluorine-based lubricant, a hydrocarbon-based lubricant, and a mixture thereof.

  According to the manufacturing method of the present embodiment, since the magnetic layer 2 is directly patterned by the mask material 10, a clear magnetic recording pattern MP can be formed. As a result, it is possible to increase the density of the magnetic recording pattern MP, and it is possible to prevent writing blur when performing magnetic recording on a discrete track type magnetic recording medium. Therefore, it is possible to provide a magnetic recording medium having a high surface recording density.

  In addition, the manufacturing method according to the present embodiment does not involve a mask layer or resist layer forming process or a processing process unlike the conventional manufacturing method. Therefore, the manufacturing process can be greatly simplified as compared with the conventional manufacturing method. Further, the mask material 10 of the present invention can be used repeatedly for the production of a plurality of magnetic recording media. Therefore, the manufacturing cost of the magnetic recording medium can be significantly reduced.

  Next, the configuration of the magnetic recording / reproducing apparatus of the present invention is shown in FIG. The magnetic recording / reproducing apparatus of the present invention includes the above-described magnetic recording medium 30 of the present invention, a rotational drive unit 31 that rotationally drives the magnetic recording medium in the recording direction, and recording and reproducing operations on the magnetic recording medium 30. A magnetic head 32 to be performed, a head drive unit 33 for moving the magnetic head 32 in the radial direction of the magnetic recording medium 30, and a recording / reproducing signal for performing signal input to the magnetic head 32 and output signal reproduction from the magnetic head 32 And a recording / reproducing signal system 34 for performing processing means.

  In this magnetic recording / reproducing apparatus, by using the discrete track type magnetic recording medium 30, it is possible to eliminate writing blur when performing magnetic recording on the magnetic recording medium 30 and to obtain a high surface recording density. That is, by using the magnetic recording medium 30, a magnetic recording / reproducing apparatus having a high recording density can be configured. In addition, by processing the recording track of the magnetic recording medium 30 magnetically discontinuously, conventionally, the reproducing head width is made narrower than the recording head width in order to eliminate the influence of the magnetization transition region at the track edge portion. What was supported can be operated with both of them approximately the same width. As a result, sufficient reproduction output and high SNR can be obtained.

  Furthermore, by configuring the reproducing unit of the magnetic head 32 as a GMR head or TuMR head, a sufficient signal intensity can be obtained even at a high recording density, and a magnetic recording apparatus having a high recording density can be realized. it can. Further, when the flying height of the magnetic head 32 is set to 0.005 μm to 0.020 μm, which is lower than the conventional one, the output is improved and a high device SNR can be obtained, and a large capacity and highly reliable magnetism is obtained. A recording apparatus can be provided.

  Further, when the signal processing circuit based on the maximum likelihood decoding method is combined, the recording density can be further improved. For example, the track density is 100 k tracks / inch or more, the linear recording density is 1000 k bits / inch or more, and the recording density is 100 G bits or more per square inch. A sufficient SNR can also be obtained when recording / reproducing.

  Hereinafter, the effects of the present invention will be made clearer by examples. In addition, this invention is not limited to a following example, In the range which does not change the summary, it can change suitably and can implement.

(Example)
First, the vacuum chamber in which the HD glass substrate (nonmagnetic substrate 1) was set was evacuated to 1.0 × 10 ⁻⁵ Pa or less in advance. The glass substrate used here is composed of Li ₂ Si ₂ O ₅ , Al ₂ O ₃ —K ₂ O, Al ₂ O ₃ —K ₂ O, MgO—P ₂ O ₅ , Sb ₂ O ₃ —ZnO. It is made of crystallized glass and has an outer diameter of 65 mm, an inner diameter of 20 mm, and an average surface roughness (Ra) of 2 angstroms (unit: Å, 0.2 nm).

Next, this glass substrate was DC-sputtered using FeCoB having a thickness of 600 mm as a soft magnetic layer, Ru having a thickness of 100 mm as an intermediate layer, and 70Co-5Cr-15Pt-10SiO ₂ alloy having a thickness of 150 mm as a magnetic layer 2. The thin films were sequentially laminated. This state is shown in FIG.

  Next, as shown in FIG. 2B, the mask material 10 made of quartz was held from the magnetic layer 2 while maintaining an interval of about 80 nm. A convex pattern having a track pitch of 100 nm and a track width of 50 nm is formed on the surface of the mask material 10, and the thickness e of the convex portion 10b is 120 nm and the thickness of the concave portion 10a is 40 nm.

Next, as shown in FIG. 2C, ion implantation was performed on the surface of the magnetic layer 2 through the mask material 10. The ions at this time were generated using a mixed gas of nitrogen gas 40 sccm, hydrogen gas 20 sccm, and neon 20 sccm. The amount of ions was 5.5 × 10 ¹⁵ atoms / cm ² , the ion extrusion voltage was +1500 V, the acceleration voltage was −1500 V, the implantation time was 60 seconds, and the implantation depth was 80 μm. Thereafter, the mask material 10 was removed from the magnetic layer 2.

  Next, as shown in FIG. 2D, a protective layer 9 made of C (carbon) and having an average layer thickness of 4 nm was formed on the surface of the magnetic layer 2 by P-CVD. Next, a lubricant (not shown) was applied on the protective layer 9 to produce a laminated structure of the magnetic recording medium.

  With respect to the magnetic recording medium manufactured by the above method, the magnetization amount, the coercive force amount, the electromagnetic conversion characteristics (SNR and 3T-squash), and the head flying height (glide avalanche) were measured. Here, the electromagnetic conversion characteristics were evaluated by a spin stand. Further, as an evaluation head, a perpendicular recording head was used for recording and a TuMR head was used for reading, and an SNR value and 3T-squash when a 750 kFCI signal was recorded were measured.

As a result of this measurement, the SNR of the magnetic recording medium was 14.2 dB, and 3T-squash was 93%, and the RW characteristics were excellent, and the head flying characteristics were stable. That is, it was confirmed that the smoothness of the surface of the magnetic recording medium was high, and that the separation characteristics by the nonmagnetic portion between the tracks of the magnetic layer 2 were excellent.
In addition, the above magnetic recording medium was manufactured for 8000 sheets using the same quartz mask material. The SNR of the 8000th magnetic recording medium was 14.0 dB, and 3T-squash was 89%, which was within the allowable range. It was.

  Since the magnetic recording medium of the present invention has a clear magnetic recording pattern, it has excellent magnetic recording pattern separation performance. Therefore, it is not affected by signal interference between adjacent patterns and has excellent high recording density characteristics. In addition, since the magnetic recording medium can be manufactured with a small number of processes, its productivity is high. Therefore, industrial applicability is high.

DESCRIPTION OF SYMBOLS 1 ... Nonmagnetic board | substrate, 2 ... Magnetic layer, 8 ... Non-magnetization area | region, 9 ... Protective layer, 10 ... Mask material, 10a ... Concave part, 10b ... Convex part, 31 ... Rotation drive part, 32 ... Magnetic head, 33 ... Head drive unit 34... Recording / reproducing signal system 30... Magnetic recording medium, d... Concave portion thickness, convex portion thickness... E, MP ... magnetic recording pattern, 101. ... Mask layer, 104 ... Resist layer, 105 ... Stamp, 108 ... Resist recess

Claims (4)

After the magnetic layer was formed on the nonmagnetic substrate, ions were partially implanted into the magnetic layer, so that the magnetic properties of the magnetic layer where the ions were implanted were modified and magnetically separated. A method of manufacturing a magnetic recording medium for forming a magnetic recording pattern,
The magnetic recording pattern formed on the surface of the mask material by irradiating ions from above the mask material after arranging a mask material that can be used repeatedly on the magnetic layer while maintaining a gap from the magnetic layer Through the concave portion of the concave-convex pattern corresponding to, ions are partially implanted into the magnetic layer underneath ,
As the mask material made of silica, the thickness in the recess of the uneven pattern is in the range of 20 nm to 50 nm, thickness at the convex portion of the concavo-convex pattern is characterized Rukoto used as is in the range of 80nm~500nm A method of manufacturing a magnetic recording medium. 2. The method of manufacturing a magnetic recording medium according to claim 1, wherein in the ion irradiation step, an interval between the magnetic layer and the mask material is set to 1 μm or less. Method for producing the ions, nitrogen, oxygen, helium, magnetic recording medium according to claim 1 or 2, characterized in that it comprises any one or more selected from the group consisting of neon. After removing the mask material, manufacturing method of a magnetic recording medium according to any one of claims 1 to 3, characterized in that a step of forming a protective layer on the magnetic layer.

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