JP5415745B2 - Magnetic storage medium manufacturing method, magnetic storage medium, and information storage device - Google Patents

Description

  The present invention relates to a manufacturing method for manufacturing a magnetic storage medium, a magnetic storage medium, and an information storage device including the magnetic storage medium.

  Hard disk drives (HDD) have become the mainstream of information storage devices as mass storage devices capable of high-speed data access and high-speed transfer. With respect to this HDD, the surface recording density has been increasing at a high annual rate so far, and further improvement in recording density is still required.

  In order to improve the recording density of the HDD, it is necessary to reduce the track width and the recording bit length. However, if the track width is reduced, so-called interference tends to occur between adjacent tracks. This interference refers to a phenomenon in which magnetic recording information is overwritten on a non-target adjacent track during recording, or a phenomenon in which crosstalk occurs due to a leakage magnetic field from a non-target adjacent track during reproduction. It is a collective term. These phenomena all cause a decrease in the S / N ratio of the reproduction signal, and cause a deterioration in error rate.

  Bit patterned magnetic storage media and discrete track magnetic storage media have been proposed as methods for avoiding this interference and realizing high track density. Here, in a discrete track type magnetic storage medium, both sides of a track formed of a magnetic material are filled with a nonmagnetic material, and adjacent tracks are magnetically separated from each other. When adjacent tracks are separated from each other, the magnetic interaction between the tracks is small, and the above-described interference is avoided.

  Here, a conventional manufacturing method proposed as a method for manufacturing a discrete track type magnetic storage medium will be described.

  FIG. 1 is a diagram showing a conventional manufacturing method of a discrete track type magnetic storage medium.

  In the conventional manufacturing method, first, the magnetic film 2 is formed on the substrate 1 in the film forming step (A).

  Next, in the nanoimprint step (B), a resist 3 made of an ultraviolet curable resin is applied on the magnetic film 2, and the mold 4 with nano-sized grooves 4 a is placed on the resist 3. As a result, the resist 3 enters the nano-sized groove 4a, and the protrusion 3a of the resist 3 is formed. Then, the resist 3 is irradiated with ultraviolet rays through the mold 4, so that the resist 3 is cured and the protrusion 3 a is printed on the magnetic film 2. Further, after the resist 3 is cured, the mold 4 is removed.

  Thereafter, etching is performed in the etching step (C), so that the magnetic film is removed leaving the track 2a protected by the protrusion 3a of the resist 3. After the etching, the protrusion 3a of the resist 3 is removed by chemical treatment, and only the track 2a remains on the substrate 1.

  In the filling step (D), the space between the tracks 2a is filled with a nonmagnetic material. Thereafter, the surface is flattened through a flattening step (E), whereby the discrete track type magnetic storage medium 6 is completed (F).

  According to such a conventional manufacturing method, high-precision flattening is required in the flattening step (E) in order to stabilize the flying characteristics of the magnetic head on the magnetic storage medium 6. Therefore, the subject that it is necessary to perform a very complicated manufacturing process and the subject that manufacturing cost increases arise.

  Here, it is known that when ions are implanted into a magnetic film, the magnetic characteristics of the magnetic film change (see, for example, Patent Documents 1 to 4). A processing method (ion doping method) has been proposed in which ions are implanted into a magnetic film to locally change the magnetic characteristics to form a track separation state.

According to this ion doping method, ions are implanted to change the magnetic characteristics, so that complicated manufacturing processes such as etching, filling, and flattening are not required, and an increase in manufacturing cost can be significantly suppressed.
Japanese Patent Laid-Open No. 07-141642 Japanese Patent Laid-Open No. 08-129738 JP 2002-288813 A JP 2006-309841 A

  However, the above-mentioned ion doping method has a problem that ions must be implanted with an implantation amount close to a practical upper limit in order to sufficiently form a separation state between tracks. The current situation is not reached.

  Heretofore, the problem that the simple manufacturing method as described above has not been put into practical use has been described by taking a discrete track type magnetic storage medium as an example. However, such a problem is not limited to a discrete track type magnetic storage medium, and is also a problem that applies to, for example, a bit patterned type magnetic storage medium. That is, such a problem is commonly applied to a magnetic storage medium of a type including a magnetic part in which information is magnetically recorded and a low magnetic part having a magnetic characteristic weaker than the magnetic characteristic of the magnetic part. It is.

  In view of the above circumstances, an object of the present invention is to provide a simple manufacturing method capable of manufacturing the above type of magnetic storage medium, and the above type of magnetic storage medium and information storage device that can be manufactured by such a simple manufacturing method. To do.

A magnetic storage medium manufacturing method of a basic form for achieving the above object is
A granular layer having a granular structure in which a plurality of magnetic particles made of a magnetic material are separated from each other by a non-magnetic material, and a soft magnetic layer made of a soft magnetic material are arranged in order of the granular layer and the soft magnetic layer from the substrate side. A magnetic film forming process for stacking and forming a magnetic film having a laminated structure;
With respect to the magnetic film, in the thickness direction of the magnetic film, the depth of the soft magnetic layer is aimed from the opposite side to the substrate side, and a predetermined protective region is excluded in the direction in which the magnetic film spreads. And an ion implantation process in which ions are locally implanted into another region.

A magnetic storage medium of a basic form that achieves the above object is
A substrate,
A granular layer having a granular structure in which a plurality of magnetic particles made of a magnetic material are separated from each other by a nonmagnetic material and a soft magnetic layer made of a soft magnetic material are arranged in the order of the granular layer and the soft magnetic layer from the substrate side. A magnetic part having a laminated structure laminated with a magnetic part on which information is magnetically recorded,
A magnetic film having a laminated structure that is continuous with the laminated structure of the magnetic part has an implanted film in which ions are implanted from the opposite side of the substrate to the depth of the soft magnetic layer. And a low magnetic part having a magnetic characteristic weaker than the magnetic characteristic of the part.

An information storage device of a basic form that achieves the above object,
A substrate,
A granular layer having a granular structure in which a plurality of magnetic particles made of a magnetic material are separated from each other by a nonmagnetic material and a soft magnetic layer made of a soft magnetic material are arranged in the order of the granular layer and the soft magnetic layer from the substrate side. A magnetic part having a laminated structure laminated with a magnetic part on which information is magnetically recorded,
A magnetic film having a laminated structure that is continuous with the laminated structure of the magnetic part has an implanted film in which ions are implanted from the opposite side of the substrate to the depth of the soft magnetic layer. A magnetic storage medium comprising a low magnetic part having a magnetic property weaker than that of the part;
A magnetic head that magnetically records and / or reproduces information to and from the magnetic part in proximity to or in contact with the magnetic storage medium; and the magnetic head is moved relative to the surface of the magnetic storage medium, A head position control mechanism for positioning the magnetic head on the magnetic part for recording and / or reproducing information by the magnetic head;
It is provided with.

  According to the magnetic storage medium manufacturing method, magnetic storage medium, and information storage device of these basic forms, a magnetic film having a laminated structure of a granular layer and a soft magnetic layer is used as a magnetic film used for magnetic information recording. A film is formed. According to this laminated structure, the magnetization reversal in the soft magnetic layer helps the magnetization reversal in the granular layer, thereby facilitating information recording without impairing the resistance to thermal fluctuation caused by the strong magnetic anisotropy of the granular layer. Will be achieved.

  By the way, in the ion implantation into the magnetic film having a laminated structure composed of the granular layer and the soft magnetic layer in the above-described ion doping method, ions are conventionally implanted aiming at the granular layer. However, in the magnetic film having this laminated structure, the ion implantation aimed at the soft magnetic layer on the upper side of the granular layer weakens the magnetic characteristics of the implantation site more efficiently than the ion implantation aimed at the granular layer. The developer found that this is possible. According to the discovery of this developer, according to the ion implantation aimed at the soft magnetic layer, it is possible to reduce the ion implantation energy and the implantation amount and to have a margin for the practical upper limit. According to each of the above basic forms, ion implantation is performed aiming at the soft magnetic layer by utilizing such properties in the laminated structure of the granular layer and the soft magnetic layer. That is, according to each of the above basic modes, a bit patterned type or discrete track type magnetic storage medium or information storage device is realized by the above-described simple manufacturing method that locally reduces the saturation magnetization of the magnetic film. Can be manufactured.

  As described above, according to the present embodiment, a simple manufacturing method capable of manufacturing a magnetic storage medium, and a magnetic storage medium and an information storage device that can be manufactured by such a simple manufacturing method can be obtained.

  Specific embodiments of the magnetic storage medium manufacturing method, the magnetic storage medium, and the information storage device described above for the basic form will be described below with reference to the drawings.

  FIG. 2 is a diagram showing an internal structure of a hard disk device (HDD) which is a specific embodiment of the information storage device.

  A hard disk device (HDD) 100 shown in this figure is incorporated in a host device such as a personal computer and is used as information storage means in the host device.

  In the hard disk device 100, a disk-shaped magnetic disk 10 is housed in a plurality of housings H so as to overlap in the depth direction of the figure. The magnetic disk 10 corresponds to a specific embodiment of the magnetic storage medium whose basic form has been described above.

Here, with respect to the basic form of the magnetic storage medium and the information storage device described above,
“The magnetic part is a strip-shaped track extending in the direction in which the magnetic film spreads,
An application mode in which the low magnetic portion is provided on both sides along the track to make the track magnetically independent is suitable.

  This application form corresponds to a discrete track type magnetic storage medium in which tracks are separated from each other by a low magnetic part. In this discrete track type magnetic storage medium, the magnetic film is continuous in the track extending direction. Here, in this application mode, since the track has the granular layer, it is possible to enjoy resistance to thermal fluctuation caused by strong magnetic anisotropy of the granular layer in the track.

  The magnetic disk 10 of FIG. 2 is a discrete track type magnetic storage medium having a plurality of concentric tracks, and corresponds to a specific embodiment of this application.

  The discrete track type magnetic storage medium is not limited to such a type having a plurality of concentric tracks, and may be, for example, one having a spiral track. good.

  The magnetic disk 10 is also a so-called perpendicular magnetic storage medium in which information is recorded in a track with a magnetic pattern by magnetization in a direction perpendicular to the front and back surfaces. The present invention is also applicable to a so-called in-plane magnetic storage medium in which information is recorded with a magnetic pattern formed by longitudinal magnetization on the front and back surfaces.

  The magnetic disk 10 rotates around the disk shaft 11 in the housing H.

  The housing H of the hard disk device 100 also houses a swing arm 20 that moves along the surface of the magnetic disk 10, an actuator 30 that is used to drive the swing arm 20, and a control circuit 50.

  The swing arm 20 holds a magnetic head 21 for writing and reading information with respect to the magnetic disk 10 at the tip. The swing arm 20 is rotatably supported by the housing H by a bearing 24. The swing arm 20 rotates within a range of a predetermined angle about the bearing 24 to move the magnetic head 21 along the surface of the magnetic disk 10. This magnetic head corresponds to an example of the magnetic head in the basic form of the information storage device described above.

  Information reading and writing by the magnetic head 21 and movement of the arm 30 are controlled by the control circuit 50, and information exchange with the host device is also performed through the control circuit 50.

  A combination of the swing arm 20, the bearing 24, the actuator 30, and the control circuit 50 corresponds to an example of the head position control mechanism in the basic form of the information storage device described above.

  FIG. 3 is a perspective view schematically showing the structure of the magnetic disk shown in FIG.

  FIG. 3 shows a part cut out from a disk-shaped magnetic disk.

  The magnetic disk 10 shown in FIG. 3 has a structure in which a plurality of tracks T are arranged concentrically around the center of the magnetic disk 10 on a substrate S, and information is magnetically recorded on each track T. Is done. The board | substrate S is corresponded to an example of the board | substrate in the above-mentioned basic form. The track T corresponds to an example of the magnetic portion in the basic form described above, and also corresponds to an example of the track in the application form described above corresponding to the discrete track type magnetic storage medium.

  Further, between the tracks T, magnetic characteristics such as saturation magnetization and coercive force are weaker than the magnetic characteristics of the tracks T, and an inter-track dividing band U that magnetically divides the tracks T from each other is obtained. The track-to-track dividing band U reduces the magnetic interaction between the tracks T. This inter-track dividing band U corresponds to an example of the low magnetic portion in the above-described basic form, and also corresponds to an example of the inter-track dividing band in the above-described applied form corresponding to the discrete track type magnetic storage medium. .

  Thus, when the magnetic interaction between the tracks T is small, there is little magnetic interference between the tracks. Therefore, according to the discrete track type magnetic disk 10 as shown in FIG. 3, the track width can be reduced and a high recording density magnetic storage medium can be realized.

  A method for manufacturing the magnetic disk 10 will be described below.

  The manufacturing method of the magnetic disk 10 corresponds to a specific embodiment of the magnetic storage medium manufacturing method described above with respect to the basic mode.

Here, for the basic form of this magnetic storage medium manufacturing method,
“The ion implantation process is a process in which a band-shaped region extending in the direction in which the magnetic film extends is used as the protective region, and ions are locally implanted into both sides along the band-shaped region”. The form is preferred.

  This application form corresponds to a magnetic storage medium manufacturing method for manufacturing a discrete track type magnetic storage medium. In the discrete track type magnetic storage medium obtained in this application mode, it is possible to enjoy the resistance to thermal fluctuation caused by the strong magnetic anisotropy of the granular layer in the track. The method of manufacturing the magnetic disk 10 described below corresponds to a specific embodiment of this application mode.

  FIG. 4 is a diagram showing a method of manufacturing the magnetic disk shown in FIGS.

  In the manufacturing method shown in FIG. 4, first, a magnetic film 62 is formed on a glass substrate 61 in the film forming step (A). This film forming step (A) corresponds to an example of a magnetic film forming process in the basic mode of the magnetic storage medium manufacturing method described above.

  In the magnetic film 62 formed in this film forming step (A), the granular layer 62a and the soft magnetic layer 62b are laminated on the substrate 61 in this order from the substrate 61 side in the order of the granular layer 62a and the soft magnetic layer 62b. Have a laminated structure.

  The granular layer 62a has a granular structure in which a plurality of columnar magnetic particles in which crystals of a magnetic material are grown in the thickness direction are separated from each other by a nonmagnetic material. In the granular layer 62a, each of the columnar magnetic particles has strong magnetic anisotropy having an easy axis of magnetization in the thickness direction of the granular layer 62a. As a result, the magnetic anisotropy of each columnar magnetic particle in the granular layer 62a allows the completed magnetic disk 10 to function as a perpendicular magnetic storage medium.

  Here, the strong magnetic anisotropy of the granular layer 62a is advantageous in that it provides a strong resistance against so-called thermal fluctuation, for example, by increasing the coercive force of the magnetic film 62. On the other hand, the strong magnetic anisotropy may cause the drawback that it is difficult to reverse the magnetization in the magnetic film 62 and information recording becomes difficult. Therefore, in this embodiment, the magnetic film 62 having a laminated structure in which the granular layer 62a and the soft magnetic layer 62b having a low coercive force are stacked is formed. According to this laminated structure, the magnetization reversal in the soft magnetic layer 62b helps the magnetization reversal in the granular layer 62a, thereby facilitating information recording without impairing the resistance to thermal fluctuation.

  Next, in the nanoimprint process (B), a resist 63 made of an ultraviolet curable resin is applied on the magnetic film 62, and a mold 64 with nano-sized grooves 64 a is placed on the resist 63. As a result, the resist 63 enters the nano-sized groove 64a, and the protrusion 63a of the resist 63 is formed. Then, the resist 63 is irradiated with ultraviolet rays through the mold 64, whereby the resist 63 is cured and the protrusions 63 a are printed on the magnetic film 62. Further, the mold 64 is removed after the resist 63 is cured.

  After the nanoimprint process (B), the process proceeds to the ion implantation process (C). In this ion implantation step (C), oxygen ions or nitrogen ions are irradiated from above the magnetic film 62 on which the protrusions 63a are printed. As a result, ions are implanted into the magnetic film 62 leaving the tracks 62c protected by the protrusions 63a of the resist 63, and the saturation magnetization and the coercive force are reduced. At this time, in this ion implantation step (C), ion implantation is performed aiming at the soft magnetic layer 62b which is the upper layer side in the laminated structure of the magnetic film 62.

  Here, in the magnetic film having a laminated structure such as the magnetic film 62 described above, the ion implantation targeting the soft magnetic layer on the upper side of the granular layer can be performed more efficiently than the ion implantation targeting the granular layer. The developer of this case has found that the magnetic properties of the part can be weakened.

  Ions implanted aiming at the soft magnetic layer reach the granular layer by diffusion. And from this developer's discovery, it was found that ion implantation into the granular layer after this diffusion has a higher effect of weakening the magnetic properties than ion implantation aimed directly at the granular layer. As a result, according to the ion implantation aimed at the soft magnetic layer, the magnetic characteristics can be efficiently reduced with a smaller implantation amount than the ion implantation aimed at the granular layer. In addition, since the soft magnetic layer is positioned above the granular layer, the ion implantation aimed at the soft magnetic layer can effectively reduce the magnetic characteristics with a small implantation energy. .

  In this ion implantation step (C), the magnetic characteristics such as saturation magnetization and coercive force are efficiently reduced by ion implantation aimed at the soft magnetic layer 62b using the discovery of the developer. This ion implantation step (C) corresponds to an example of the ion implantation step in the basic form described above.

Here, in contrast to the basic form described above,
An application form that “the ion implantation process is a process using at least one of oxygen ions and nitrogen ions as the ions” is preferable.

  This is because oxygen ions and nitrogen ions can more effectively degrade the magnetic properties of the magnetic film than when other ions are implanted. The ion implantation step (C) in FIG. 4 corresponds to an example of an ion implantation process in this application mode.

In contrast to the basic form described above,
“It further includes a mask forming process for forming a mask on the magnetic film that inhibits ion implantation into the protective region,
The ion implantation process is a process in which ions are locally implanted into other regions other than the protection region protected by the mask by applying ions from the magnetic film on which the mask is formed. Is also suitable.

  According to this application mode, a portion that does not require ion implantation is reliably protected by the mask, and the track formation accuracy is high. The nanoimprint process (B) in FIG. 4 corresponds to an example of a mask formation process in this application form, and the ion implantation process (C) corresponds to an example of an ion implantation process in this application form.

Also, for this preferred application with mask formation process,
"The mask forming process is a process of forming the mask with a resist",
An application form that “the mask forming process is a process of forming the mask with a resist by a nanoimprint process” is more preferable.

  Mask formation with a resist is technically stable and high-precision mask formation can be expected. Mask formation by a nanoimprint process is preferable because a mask pattern at a nano level can be easily created. The nanoimprint process (B) shown in FIG. 4 also corresponds to an example of a mask formation process in these more preferable applications.

  In the nanoimprint described above, the resist is not completely removed even at the location where ions are to be implanted. However, when the resist is thin, ions pass through the resist and are injected into the magnetic film 62. When the resist is thick (that is, where the protrusions 63a are formed), the ions stop at the resist and do not reach the magnetic film. . Therefore, a desired track pattern can be formed.

  The acceleration voltage corresponding to the ion implantation energy is set so that ions are implanted into the soft magnetic layer 62b of the magnetic film 62 as described above. The acceleration voltage to be set differs depending on the ion species, and this soft magnetism is set. It varies depending on the depth and material up to the layer 62b. Thus, in the magnetic film 62 at the location where ions are implanted, the ions remain inside and the crystal structure is distorted and the coercive force and saturation magnetization are lowered. After the ion implantation, the resist protrusion 63a is removed by chemical treatment.

  Through such an ion implantation step (C), an inter-track dividing band 62d that divides the magnetic interaction between the tracks 62c is formed between the tracks 62c, and a bit-patterned magnetic storage medium 10 completed (D). Since the saturation magnetization and the coercive force in the inter-track separation band 62d are sufficiently smaller than the saturation magnetization and the coercivity of the track 62c, information is recorded only in the track 62c, and no information is recorded and retained in the inter-track separation band 62d.

  In the magnetic storage medium 10 manufactured by the manufacturing method shown in FIG. 4, the smoothness of the track 62c and the inter-track dividing band 62d constituting the surface is the magnetic film 62 formed in the film forming step (A). The smoothness is maintained as it is. Therefore, the planarization step as in the prior art shown in FIG. 1 is not necessary, and the manufacturing method shown in FIG. 4 is a simple method.

  In the manufacturing method shown in FIG. 4, the track 62 c is protected by a resist protrusion 63 a printed on the magnetic film 62. Accordingly, the entire surface of the magnetic storage medium 10 can be irradiated with ions at the same time, and ion implantation to a required portion can be sufficiently realized by ion irradiation for several seconds, so that mass productivity is not impaired.

  Further, in the manufacturing method shown in FIG. 4, the magnetic characteristics of the magnetic film 62 are efficiently reduced by ion implantation aiming at the soft magnetic layer 62b with a small implantation amount and a small implantation energy. Thereby, in the manufacturing method shown in FIG. 4, it is possible to give a margin to the practical upper limit for the ion implantation energy and the implantation amount. That is, according to the manufacturing method shown in FIG. 4, the discrete track type magnetic disk 10 can be actually manufactured by a simple method using an ion doping method.

  In the examples described below, the technical effects were confirmed by applying the manufacturing method shown in FIG. 4 to specific materials and the like.

  FIG. 5 is a diagram illustrating an embodiment.

  A well-cleaned glass substrate 70 was set in a magnetron sputtering apparatus, and a soft magnetic backing layer 71 having a thickness of 50.5 nm was formed. The soft magnetic backing layer 71 functions as a magnetic path of a recording magnetic field applied during information recording, and has the following three-layer structure. In the manufacturing method shown in FIG. 4, the description of the process of forming the soft magnetic backing layer 71 is omitted.

  The soft magnetic backing layer 71 has a thickness of 25 nm and two soft magnetic layers 71a made of a Co—Fe—Zr—Ta based alloy sandwich a nonmagnetic split layer 72b made of Ru and having a thickness of 0.5 nm. It has a three-layer structure. Further, in this three-layer structure, the two soft magnetic layers 71a are antiferromagnetically coupled by the nonmagnetic dividing layer 72b. Thereby, the leakage magnetic flux from this soft magnetic backing layer 71 is suppressed.

  Subsequently, (001) crystal-oriented hcp-Ru is formed on the soft magnetic underlayer 71 as a base layer 72 for crystal orientation of the columnar magnetic particles forming the granular layer in the magnetic layer with a thickness of 20 nm. did. The process for forming the underlayer 72 is also omitted in the manufacturing method shown in FIG.

Thereafter, a magnetic film 73 having a laminated structure in which a granular layer 73a and a soft magnetic layer 73b are laminated in this order from the underlayer 71 side is formed on the underlayer 71. The granular layer 73a has a granular structure in which a plurality of columnar magnetic particles made of a Co—Cr—Pt base alloy that is a magnetic material are separated from each other by TiO ₂ that is a nonmagnetic material. The soft magnetic layer 73b is made of a Co—Cr—Pt—B base alloy, which is a soft magnetic material. Further, the granular layer 73a has a thickness of 12 nm and the soft magnetic layer 73b has a thickness of 9 nm. As a result, the entire magnetic film 73 has a thickness of 21 nm. Soft magnetic materials include Co—Cr—Pt—B based alloys, Co—Cr—Pt—Ta based alloys, Co—Cr—Pt based alloys, Ni—Fe based alloys, Co—Sm based alloys and the like. It is possible to use.

  After the magnetic film 73 was formed, 4 nm of diamond-like carbon was formed as a protective layer 74. The process of forming the protective layer 74 is not described in the manufacturing method shown in FIG.

  A resist was applied on the protective layer 74, and a resist pattern 75 composed of the above protrusions was formed using a nanoimprint process.

In this embodiment, N ²⁺ ions 76 accelerated to 9.1 keV from above the resist pattern 75 were irradiated and implanted into the magnetic film 73. The acceleration voltage of ions in this embodiment is an acceleration voltage set so that ions are implanted into the central portion of the soft magnetic layer 73b on the upper layer side in the laminated structure of the magnetic film 73. The N ²⁺ ions 76 implanted into the soft magnetic layer 73b by this acceleration voltage are diffused into the granular layer 73a, as schematically shown in FIG.

  After the ion implantation, the resist pattern 75 was removed by SCl cleaning to obtain an example.

Next, a laminate equivalent to this example was irradiated with N ²⁺ ions 76 accelerated to 17.6 keV and injected into the magnetic film 73 to obtain a comparative example for this example. The acceleration voltage of ions in this comparative example is an acceleration voltage set so that ions are implanted into the central portion of the granular layer 73a, which is the lower layer side in the laminated structure of the magnetic film 73.

  6 and 7 are graphs showing the effect of ion implantation in Examples and Comparative Examples.

  The graph G1 shown in FIG. 6 shows the effect of reducing the coercive force Hc with respect to the ion implantation amount, and the graph G2 shown in FIG. 7 shows the effect of reducing the normalized saturation magnetization Ms with respect to the ion implantation amount. Yes. In both the graph G1 of FIG. 6 and the graph G2 of FIG. 7, the horizontal axis represents the ion implantation amount, the vertical axis of the graph G1 of FIG. 6 is the coercive force Hc, and the vertical axis of the graph G2 of FIG. It represents the magnetization Ms. In the graph G2 in FIG. 7, the normalized saturation magnetization Ms is shown as a percentage of the saturation magnetization before ion implantation.

  Further, in the graph G1 shown in FIG. 6, the coercive force Hc reduction effect in the example is indicated by the first line L1 connecting the circled plot points, and the coercivity Hc reduction effect in the comparative example is plotted by the square mark. Is shown by a second line L2. In the graph G2 shown in FIG. 7, the effect of reducing the normalized saturation magnetization Ms in the example is indicated by a third line L3 connecting the plotted points with circles, and the effect of reducing the normalized saturation magnetization Ms in the comparative example is indicated by a square mark. This is indicated by a fourth line L4 connecting the plot points.

From these two graphs G1 and G2, the example in which the ion implantation energy (acceleration voltage) is smaller for both the coercive force Hc and the normalized saturation magnetization Ms than the comparative example in which the implantation energy (acceleration voltage) is large. It can be seen that the reduction effect is great. In particular, with respect to the coercive force Hc, the coercive force Hc disappears from the graph G1 shown in FIG. 6 at an injection amount 2 × 10 ¹⁶ atoms / cm ² that is approximately half of the injection amount 4 × 10 ¹⁶ atoms / cm ² in the comparative example. I can see that

  Here, the implantation energy and the amount of ions implanted in the above-described ion implantation have practical upper limits determined by demands for preventing deterioration of the surface state after implantation. In particular, the ion implantation amount has a strong influence on the surface state and is preferably suppressed as much as possible.

  According to the graphs G1 and G2 described above, according to the ion implantation (example) aiming at the soft magnetic layer 73b, the implantation energy and the ion implantation amount required for reducing the magnetic characteristics are the ion implantation aimed at the granular layer 73a ( It can be seen that it is much smaller than the comparative example). As a result, according to the ion implantation (example) aiming at the soft magnetic layer 73b, it is possible to give a margin to the practical upper limit for the implantation energy and the ion implantation amount required for reducing the magnetic characteristics. Become. Since such a margin is obtained, according to the ion implantation aiming at the soft magnetic layer 73b, the discrete track type magnetic disk 10 can be practically manufactured by a simple method using an ion doping method. It will be possible.

  In the above description, a discrete track type magnetic storage medium is illustrated as an example of the magnetic storage medium. However, the magnetic storage medium is not limited to this discrete track type, and is, for example, a bit patterned type. Also good.

  In the above description, the use of a resist pattern as a preferred mask for forming magnetic dots is exemplified. On the other hand, in the ion implantation in the basic form described above, a process in which a stencil mask is arranged on the very surface of the medium so as not to contact the medium surface may be used. According to this process, the steps of resist coating and resist removal can be omitted.

  In the above description, it is shown that the nanoimprint process is used as the best example of resist patterning. However, electron beam exposure may be used for patterning.

It is a figure which shows the conventional manufacturing method of a discrete track | truck type magnetic storage medium. It is a figure which shows the internal structure of the hard disk drive (HDD) which is one specific embodiment of an information storage device. FIG. 3 is a perspective view schematically showing the structure of the magnetic disk shown in FIG. 2. It is a figure which shows the manufacturing method of the magnetic disc shown in FIG. 2 and FIG. It is a figure which shows an Example. It is a graph which shows the effect of the ion implantation in an Example and a comparative example. It is a graph which shows the effect of the ion implantation in an Example and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Hard disk drive 10 Magnetic disk 61 Substrate 62 Magnetic film 62a Granular layer 62b Soft magnetic layer 62c Track 62d Inter-track separation zone

Claims (10)

A granular layer having a granular structure in which a plurality of magnetic particles made of a magnetic material are separated from each other by a non-magnetic material, and a soft magnetic layer made of a soft magnetic material are arranged in order of the granular layer and the soft magnetic layer from the substrate side. A magnetic film forming process for forming a magnetic film having a laminated structure by laminating so as to be in contact;
With respect to the magnetic film, in the thickness direction of the magnetic film, the depth of the soft magnetic layer is aimed from the opposite side to the substrate side, and a predetermined protective region is excluded in the direction in which the magnetic film spreads. An ion implantation process for implanting ions locally to other regions,
A method of manufacturing a magnetic storage medium, wherein ions implanted into the soft magnetic layer diffuse into the granular layer.   The ion implantation process is a process in which ions are locally implanted into both sides along the belt-shaped region using a belt-shaped region extending in a direction in which the magnetic film spreads as the protective region. The method of manufacturing a magnetic storage medium according to claim 1.   3. The method of manufacturing a magnetic storage medium according to claim 1, wherein the ion implantation step is a step of using at least one of oxygen ions and nitrogen ions as the ions. A mask forming step of forming a mask on the magnetic film that inhibits ion implantation into the protection region;
The ion implantation process is a process in which ions are locally implanted into other regions except for the protection region protected by the mask by applying ions from above the magnetic film on which the mask is formed. The method of manufacturing a magnetic storage medium according to claim 1, wherein the magnetic storage medium is a magnetic storage medium.   5. The method of manufacturing a magnetic storage medium according to claim 4, wherein the mask forming process is a process of forming the mask with a resist.   6. The method of manufacturing a magnetic storage medium according to claim 4, wherein the mask forming step is a step of forming the mask with a resist by a nanoimprint process. A substrate,
A granular layer having a granular structure in which a plurality of magnetic particles made of a magnetic material are separated from each other by a nonmagnetic material and a soft magnetic layer made of a soft magnetic material are arranged in the order of the granular layer and the soft magnetic layer from the substrate side. A magnetic part having a laminated structure laminated so as to be in contact with each other, and a magnetic part in which information is magnetically recorded,
Have a layered structure continuous with the laminated structure of the magnetic portion, ions in the soft magnetic layer of the laminated structure is injected, the granular layer of the laminated structure by the ions from the soft magnetic layer is diffused And a low magnetic part having a magnetic characteristic weaker than the magnetic characteristic of the magnetic part. The magnetic part is a strip-like track extending in a direction in which the magnetic film spreads;
8. The magnetic storage medium according to claim 7, wherein the low magnetic part is provided on both sides along the track to magnetically isolate the track. A substrate,
A granular layer having a granular structure in which a plurality of magnetic particles made of a magnetic material are separated from each other by a nonmagnetic material and a soft magnetic layer made of a soft magnetic material are arranged in the order of the granular layer and the soft magnetic layer from the substrate side. A magnetic part having a laminated structure laminated so as to be in contact with each other, and a magnetic part in which information is magnetically recorded,
Have a layered structure continuous with the laminated structure of the magnetic portion, ions in the soft magnetic layer of the laminated structure is injected, the granular layer of the laminated structure by the ions from the soft magnetic layer is diffused a magnetic storage medium having a low magnetic portion having a weak magnetic properties than the magnetic properties of the magnetic portion;
A magnetic head that magnetically records and / or reproduces information to and from the magnetic unit in proximity to or in contact with the magnetic storage medium; and moving the magnetic head relative to the surface of the magnetic storage medium, A head position control mechanism for positioning the magnetic head on a magnetic part for recording and / or reproducing information by the magnetic head;
An information storage device comprising: The magnetic part is a strip-like track extending in a direction in which the magnetic film spreads;
The information storage device according to claim 9, wherein the low magnetic portion is provided on both sides along the track to magnetically isolate the track.

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