JP2020035506A - Master for transferring magnetic pattern and manufacturing method thereof, and magnetic pattern transferring method - Google Patents

Abstract

To provide a master for transferring a magnetic pattern and a manufacturing method thereof, and a magnetic pattern transferring method, capable of sufficiently making writing efficiency high when transferring a magnetic pattern to a magnetic recording medium.SOLUTION: As shown in FIG. 4(a), a slave 10 fixed uniform magnetization and a master 20 fixed magnetization in a uniform direction are prepared. Next, as shown in FIG. 4(b), the master 20 in this state is brought into close contact with a magnetic recording layer 12 of the slave 10. When a bias magnetic field B3 is applied to the master 20 in this state as described above, the magnetization of a first magnetic body layer 22 is not inverted, and only the magnetization of a second magnetic body layer 23 is inverted, thereby, as shown in FIG. 4(c), a recording magnetic field B4 is generated. Therefore, after the bias magnetic field B3 and the master 20 are removed, as shown in FIG. 4(d), the magnetization in a non-inversion region 12B can be set to an initial magnetization M0, and the magnetization in an inversion region 12A can be set to a rewritten magnetization M1 in an opposite direction thereto.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a magnetic pattern transfer master used for recording a fixed pattern on a magnetic recording medium, a method for manufacturing the same, and a magnetic pattern transfer method using the magnetic pattern transfer master.

  When recording or reading data on a high-density magnetic recording medium such as a hard disk, it is necessary to control the magnetic head by bringing the magnetic head close to the magnetic recording medium. As the recording density increases, high precision is required for controlling the positional relationship between the magnetic recording medium and the magnetic head at this time. For this reason, a part of the magnetic recording medium is provided with a dedicated signal used for appropriately guiding the magnetic head to improve the position accuracy, separately from data to be recorded when the magnetic recording medium is originally used. Are recorded. Although it is not impossible to record this servo signal on a magnetic recording medium in the same manner as ordinary data, especially when a large amount of magnetic recording medium is produced, this method uses the servo signal on each magnetic recording medium. Since it takes a long time to record the data, the production efficiency is significantly reduced.

  In the case of mass-producing magnetic recording media, since a servo signal to be recorded is common, a master (a master for magnetic pattern transfer) corresponding to the servo signal is manufactured in advance, and a newly manufactured magnetic recording medium ( By transferring the recording pattern corresponding to the servo signal in the master to the slave, the working time for recording the servo signal can be greatly reduced. FIG. 8 shows an example of the slave (a), the servo signal (b), and the master (c) in this case. In FIG. 8A, a slave 10, which is a magnetic recording medium, has a flat plate shape in which a magnetic recording layer 12 made of a ferromagnetic material is formed on a slave substrate 11. When a uniform magnetic field in the normal direction (slave initialization magnetic field B0) is applied to the slave 10, the magnetic recording layer 12 is uniformly formed by the initial magnetization M0 in the same direction as the slave initialization magnetic field B0. Magnetizes. Here, the arrow indicates the direction of magnetization. In FIG. 8A, the magnetic recording layer 12 is shown divided in the in-plane direction for convenience, but this division is a virtual one corresponding to the following description. Further, since the slave 10 is used later as a hard disk, the surface of the magnetic recording layer 12 has high flatness so as not to come into contact with the magnetic head.

  FIG. 8B shows an example of a servo signal to be recorded on the slave 10 here, which corresponds to a two-dimensional magnetic recording pattern to be formed on the surface of the slave 10 (magnetic recording layer 12). In FIG. 8B, the direction of magnetization on the surface of the magnetic recording layer 12 is set to be reversed between the hatched area and the non-hatched area. That is, for example, the magnetization of the hatched area in FIG. 8B is directed toward the front of the paper, and the magnetization of the unhatched area is directed toward the rear of the paper (or vice versa).

  FIG. 8C is a perspective view showing a structure of the master 90 formed corresponding to a part of the servo signal. The master 90 is made of a magnetic material, and has irregularities formed on the surface thereof corresponding to the magnetic recording pattern of the servo signal. In particular, the projections serve as magnetic paths. Note that the master 90 may also include the same substrate as the slave 10, but the description is omitted here. Here, for example, in the range of X in FIG. 8B, this magnetic recording pattern is a simple line and space pattern in the horizontal direction (one-dimensional) in the figure. Hereinafter, a portion corresponding to the range of X in the master 90 and the slave 10 will be described. In FIG. 8C, the irregularities formed on the master 90 are formed so as to correspond to the line & space pattern. The convex portion 90A of the master 90 corresponds to a hatched region in the range of X in FIG. 8B, and the concave portion 90B corresponds to a non-hatched region.

  FIG. 9 schematically illustrates a situation where writing is performed on the slave 10 of FIG. 8A by the master 90 of FIG. 8C along a vertical cross section. As shown in FIG. 9A, the surface of the slave 10 to which the initial magnetization M0 is uniformly applied as shown in FIG. The master 90 contacts the magnetic recording layer 12 so that the projection 90A of the master 90 contacts the magnetic recording layer 12. In this state, as shown in FIG. 9B, when a transfer magnetic field B1 that is opposite to the initialization magnetic field B0 as viewed from the slave 10 is applied, the transfer magnetic field B1 causes the protrusion 90A to move into the slave 10 from the convex portion 90A. A magnetic field (recording magnetic field B5) is generated, and the direction of the recording magnetic field B5 is opposite to the initial magnetization M0. For this reason, after the master 90 is removed, the magnetization of the rewrite magnetization M1 in the region (reversal region 12A) on the side of the magnetic recording layer 12 in contact with the protrusion 90A of the master 90 is opposite to the initial magnetization M0. Becomes If the magnetic field heading toward the slave 10 via the recess 90B can be neglected, in the region (non-inversion region 12B) on the side of the magnetic recording layer 12 corresponding to the recess 90B, no reversal of magnetization occurs, and the magnetization remains at the initial magnetization M0. Becomes Therefore, a magnetic recording pattern corresponding to the range of X in FIG. 8B is formed on the magnetic recording layer 12.

  In the above example, the pattern corresponding to the servo signal is described as a simple line & space pattern. However, the convex portion is formed as a two-dimensional pattern so as to correspond to the hatched area in FIG. 8B. By using the formed master, the pattern of FIG. 8B can be directly transferred to the slave by the above method.

  When a servo signal is transferred to the slave 10 using such a master 90, a simple process of applying the transfer magnetic field B1 by bringing the master 90 into contact with the slave 10 as described above is used. The time required for the process is short. For this reason, a magnetic recording medium (slave 10) on which servo signals have been recorded can be obtained with high productivity. Further, if the servo signals are common, the common master 90 corresponding to the servo signals can be repeatedly used for a large number of magnetic recording media, so that the increase in the manufacturing cost due to manufacturing the master is slight. It is necessary to make the concavo-convex pattern formed on the master finer with the increase in recording density, but this pattern can be easily formed using, for example, electron beam lithography.

  Patent Documents 1 and 2 disclose that in a master having such a concavo-convex structure, the absolute value of the initial magnetization M0 or the rewriting magnetization M1 after transfer is adjusted by adjusting the structure of the magnetic material particularly on the surface of the projection. Is described that can keep the magnetization large (increase the contrast of magnetization). As a result, write errors can be reduced, and the magnetic recording medium can be made particularly inexpensive.

JP 2009-259372 A JP 2009-295250 A

  However, in the state of FIG. 9B, the non-inversion region 12B (the region adjacent to the inversion region 12A) in the magnetic recording layer 12 of the slave 10 is actually affected by the transfer magnetic field B1. Originally, the magnetization in the non-inversion region 12B should be the initial magnetization M0 as described above, but this may affect the magnetization in the non-inversion region 12B. Alternatively, since the magnetic field leaks to the non-inversion region 12B, it is difficult to sufficiently increase the recording magnetic field B5 in the inversion region 12A, and it is difficult to sufficiently increase the writing efficiency. That is, it has been required to sufficiently increase the writing efficiency when a magnetic pattern is transferred to a magnetic recording medium (slave) using a master.

  The present invention has been made in view of the above problems, and has as its object to provide an invention that solves the above problems.

The present invention has the following configurations in order to solve the above problems.
The master for transferring a magnetic pattern of the present invention is a master for transferring a magnetic pattern, which serves as a master for transferring a preset magnetic pattern onto the surface of a magnetic recording medium, and includes a flat substrate and a first ferromagnetic material. A first magnetic layer partially formed on the surface of the substrate in a plan view, and a second ferromagnetic material different from the first ferromagnetic material and formed on a surface of the substrate in a plan view. A second magnetic layer formed in a region other than the region where the first magnetic layer is formed, and having a different coercive force from the first magnetic layer. The height difference between the surface of the second magnetic layer and the height of the second magnetic layer is less than １ ／ of the minimum pattern width of the first magnetic layer and the second magnetic layer in plan view.
The master for magnetic pattern transfer according to the present invention, wherein one of the one magnetic layer and the second magnetic layer is formed adjacently on the surface of the substrate, the one magnetic layer and the It is characterized in that the other of the two magnetic layers is formed so as to be filled.
In the magnetic pattern transfer master according to the present invention, the surface of the first magnetic layer and the surface of the second magnetic layer exist on a common plane.
In the magnetic pattern transfer master according to the present invention, the first ferromagnetic material and the second ferromagnetic material are alloys containing Fe or Co, respectively.
The method for manufacturing a master for magnetic pattern transfer according to the present invention is the method for manufacturing a master for magnetic pattern transfer, wherein a first magnetic layer forming step of forming the first magnetic layer on the substrate; The second magnetic layer is formed such that the region where the first magnetic layer is not formed is embedded in the region where the first magnetic layer is formed and the region where the first magnetic layer is not formed in plan view. A second film forming step of forming a magnetic material, and removing the second ferromagnetic material on the first magnetic layer to expose the first magnetic layer when viewed from above, A flattening step of forming the second magnetic layer in a region where the first magnetic layer is not formed.
In the method of manufacturing a master for magnetic pattern transfer according to the present invention, the flattening step is performed by chemical mechanical polishing.
In the method for manufacturing a master for magnetic pattern transfer according to the present invention, in the first magnetic layer forming step, the first ferromagnetic material formed after the first ferromagnetic material is formed on the substrate. It is characterized in that the material is partially removed.
The magnetic pattern transfer method of the present invention is a magnetic pattern transfer method using the magnetic pattern transfer master, wherein the magnetization of the surface of the slave as the magnetic recording medium is uniformly distributed along the normal direction of the slave. Sliding magnetization in one direction, and applying a master initialization magnetic field in the normal direction of the magnetic pattern transfer master to uniformly magnetize the surface of the magnetic pattern transfer master. A master magnetization step in one direction along the normal direction, and the surface of the magnetic pattern transfer master after the master magnetization step is brought into contact with or close to the surface of the slave after the slave magnetization step, The coercive force of one of the first magnetic layer and the second magnetic layer is larger than that of one of the first magnetic layer and the second magnetic layer. Smaller than the other coercivity, and characterized by comprising a transfer step of applying a bias magnetic field of the master initialization magnetic field and opposite to the magnetic pattern transfer master.

  Since the present invention is configured as described above, it is possible to sufficiently increase the writing efficiency when the magnetic pattern is transferred to the magnetic recording medium.

FIG. 1 is a cross-sectional view illustrating a configuration of a magnetic pattern transfer master according to an embodiment of the present invention. FIG. 4 is a diagram illustrating magnetic hysteresis characteristics of two types of magnetic materials used in the magnetic pattern transfer master according to the embodiment of the present invention. FIG. 3 is a diagram illustrating a state of magnetization before and after application of a bias magnetic field in a magnetic pattern transfer master according to an embodiment of the present invention. FIG. 4 is a diagram illustrating a method of transferring a magnetic pattern to a slave (particularly, a transfer step) using the magnetic pattern transfer master according to the embodiment of the present invention. FIG. 9 shows calculation results obtained by comparing the recording magnetic field when the magnetic pattern transfer master according to the embodiment of the present invention is used (Example) and when the conventional master is used (Comparative Example). It is a process sectional view showing a manufacturing method of a magnetic pattern transfer master concerning an embodiment of the invention. FIG. 3 is a diagram showing an embodiment in a flattening step used in the method for manufacturing a magnetic pattern transfer master according to the embodiment of the present invention. FIG. 9 is a diagram illustrating a structure of a slave (a), an example of a magnetic pattern to be transferred (b), and a structure of a master for magnetic pattern transfer (c) when a conventional magnetic pattern transfer method is performed. FIG. 4 is a diagram illustrating a magnetic pattern transfer method using a conventional magnetic pattern transfer master.

  A magnetic pattern transfer master according to an embodiment of the present invention will be described. FIG. 1 is a cross-sectional view of the magnetic pattern transfer master (master) 20, which corresponds to a state in which the master 90 in FIGS. 9A and 9B is turned upside down. 8 also shows a portion of the master 20 corresponding to the range of X in FIG. 8B, that is, a portion where the magnetic pattern to be recorded is a simple line and space. The magnetic recording medium (slave 10) onto which the magnetic pattern is transferred using the master 20 is a hard disk on which servo signals corresponding to the magnetic pattern are written, as in the above-described case. However, as will be described later, the slave 10 can be any device other than a hard disk as long as it can write a magnetic pattern, and the device on which the magnetic pattern is recorded is called a magnetic recording medium.

  In this master 20, first magnetic layers 22 and second magnetic layers 23 are alternately formed on a substrate 21, and the surface of the first magnetic layer 22 and the surface of the second magnetic layer 23 are common. Constitute a plane. Since the region where the first magnetic layer 22 (the second magnetic layer 23) is not formed is filled with the second magnetic layer 23 (the first magnetic layer 22), the surface of the master 20 is flat. You. The substrate 21 can secure a sufficient area to function as the master 20, and the first magnetic layer 22 and the second magnetic layer 23 can be formed thereon, and sufficient mechanical A non-magnetic material having strength is used, for example, a glass substrate is used.

  The first magnetic layer 22 is made of a first ferromagnetic material, and the second magnetic layer 23 is made of a second ferromagnetic material different from the first ferromagnetic material. Both have different magnetic properties. FIG. 2 is a diagram showing these magnetic hysteresis characteristics (horizontal axis: applied magnetic field, vertical axis: magnetization). Here, the magnetic hysteresis characteristic of the first magnetic layer 22 is indicated by a solid line, and the magnetic hysteresis characteristic of the second magnetic layer 23 is indicated by a dotted line. As shown here, the coercive force differs greatly between the two, and the coercive force of the first magnetic layer 22 is set to be larger than the coercive force of the second magnetic layer 23.

  Specifically, an Fe—Pt alloy or a Co—Pt alloy can be used as the first ferromagnetic material, and another Fe alloy or Co alloy can be used as the second ferromagnetic material. . These alloy compositions are appropriately set according to the coercive force, the saturation magnetization, and the like as described above.

  In the normal direction (the vertical direction in FIG. 1) in the state of FIG. 1, a magnetic field (master initialization magnetic field B2 in FIG. 2) that saturates the magnetizations of the first magnetic layer 22 and the second magnetic layer 23 together. When applied, the magnetization of the first magnetic layer 22 is M21 and the magnetization of the second magnetic layer 23 is M22. Even if the absolute values of M21 and M22 are different, their directions are equal, and they are on the negative side in FIG. The state of the magnetization of the master 20 in this case is as shown in FIG.

  Thereafter, a magnetic field (bias) having a direction opposite to the master initialization magnetic field B2 and having a strength that saturates the magnetization of the second magnetic layer 23 but does not saturate the magnetization of the first magnetic layer 22 as shown in FIG. When a magnetic field B3, | B2 |> | B3 |) is applied, the magnetization of the first magnetic layer 22 is M31 and the magnetization of the second magnetic layer 23 is M32, and from FIG. 2, M31 ≒ M21, M32 ≒ -M22. That is, by applying the bias magnetic field B3, the magnetization of the first magnetic layer 22 and the magnetization of the second magnetic layer 23 can be reversed as shown in FIG. 3B. Thus, the recording magnetic field B4 shown in FIG. 3B can be generated.

  A method of transferring a magnetic pattern when transferring a magnetic recording pattern to the slave 10 using the master 20 will be described. FIG. 4 is a diagram showing this magnetic pattern transfer method. Here, as shown in FIG. 4 (a), first, as shown in FIG. 9, the slave 10 provided with uniform magnetization and the master 20 provided with uniform magnetization as described above. Is prepared. In FIG. 4, the master 20 is shown upside down as in FIG.

  In order to obtain the slave 10 (magnetic recording layer 12) to which the initial magnetization M0 is uniformly applied, a slave initialization magnetic field B0 is applied to the slave 10 as shown in FIG. Magnetization step). Further, in order to obtain the master 20 magnetized in a uniform direction as shown in FIG. 3A, the master initialization magnetic field B2 is applied to the master 20 as described above. Thus, a master 20 is prepared in which the magnetization of the first magnetic layer 22 is M21 and the magnetization of the second magnetic layer 23 is M22 in the same direction as M21 (master magnetization step). 3A and 4A, the magnetizations M21 and M22 are similarly illustrated, but the absolute values of the magnetizations M21 and M22 do not need to be equal.

  Next, as shown in FIG. 4B, the master 20 in this state is brought into close contact with the magnetic recording layer 12 of the slave 10. As described above, since the surfaces of the slave 10 and the master 20 are flat, the surfaces can be closely adhered or the distance between these surfaces can be extremely reduced. When the bias magnetic field B3 is applied to the master 20 in this state as described above, the magnetization of the first magnetic layer 22 does not reverse as shown in FIG. Since only the magnetization is reversed, the recording magnetic field B4 is generated as shown in FIG. 4C (transfer step). The direction of the recording magnetic field B4 is opposite to the initial magnetization M0 in the reversal region 12A where the magnetization should be reversed in the magnetic recording layer 12 of the slave 10, and the same direction as the initial magnetization M0 in the non-reversal region 12B where the magnetization is not reversed. Becomes

  For this reason, after removing the bias magnetic field B3 and the master 20, as shown in FIG. 4D, the magnetization in the non-inversion region 12B is set to the initial magnetization M0 and the inversion region 12A as shown in FIG. 9C. Can be changed to the rewrite magnetization M1 in the opposite direction. However, since the recording magnetic field B4 acts in the opposite direction in the non-inversion region 12B and the inversion region 12A, the writing efficiency can be increased as compared with the case of FIG.

  FIG. 5 shows the results of calculation of the intensity distribution of the magnetic field (recording magnetic field) on the surface of the slave 10 in the cases of FIGS. 4C (Example) and 9B (Comparative Example). Here, the results are shown for a range (width 50 nm) where one set of the inversion region 12A and the non-inversion region 12B are adjacent, and the bias magnetic field B3 in the example (FIG. 4C) and the comparative example (FIG. 9). The transfer magnetic field B1 in (b) is 5 kOe. As a result, even in the range of the width of 50 nm, in the embodiment, the difference (contrast) between the recording magnetic field B3 in the inversion region 12A and the non-inversion region 12B can be increased. Thereby, the writing efficiency of the magnetic pattern can be improved.

  Next, a method of manufacturing the master 20 will be described. 6A to 6G are process cross-sectional views illustrating this manufacturing method. Here, first, as shown in FIG. 6A, a first ferromagnetic material 41 forming the first magnetic layer 22 is uniformly formed on the entire surface of the substrate 21 by a sputtering method or the like. (First film forming step). The film thickness at this time is set to the thickness of the first magnetic layer 22 in the final slave 20 (FIG. 1 and the like), and can be, for example, 10 nm. Thereafter, as shown in FIG. 6B, a photoresist layer 100 is formed using electron beam lithography. The width and interval of the photoresist layer 100 correspond to the width of the first magnetic layer 22 and the width of the second magnetic layer 23 in FIG. 1, respectively, and may be, for example, 10 nm to 15 nm. The photoresist layer 100 having such a width and an interval can be formed particularly by electron beam lithography.

  After that, as shown in FIG. 6C, the first ferromagnetic material 41 is dry-etched using the photoresist layer 100 as a mask, and then, as shown in FIG. Is removed, a patterned first magnetic layer 22 is obtained (patterning step). That is, as a first magnetic layer forming step for obtaining the first magnetic layer 22, a first film forming step (FIG. 6A) and a patterning step (FIGS. 6B and 6C) are performed. .

  Thereafter, as shown in FIG. 6E, a second ferromagnetic material 42 forming the second magnetic layer 23 is formed on the entire surface (second film forming step). The film formation method in this case can use a sputtering method or the like as in the case of FIG. 6A, and the thickness to be formed is such that the space between the adjacent first magnetic layers 22 is sufficiently filled. To a degree. The surface of the structure formed in this case is made of the second ferromagnetic material 42, and the unevenness is such that a certain portion of the first magnetic layer 22 becomes a convex portion and a portion without the first magnetic layer 22 becomes a concave portion. Is formed.

  Thereafter, a flattening process is performed on the surface in the state of FIG. 6E (flattening step). This flattening process is performed by removing the second ferromagnetic material 42 on the first magnetic layer 22 with the second ferromagnetic material 42 between the first magnetic layers 22 remaining. This is performed to obtain the magnetic layer 23. Specifically, CMP (chemical mechanical polishing) can be performed as the flattening process. FIG. 7 is a perspective view schematically showing a form when performing CMP. Here, the wafer (substrate 21) in the state shown in FIG. 6E is mounted on the lower surface of the rotating polishing jig 110 in a manner inverted from that shown in FIG. It comes into contact with the polishing board 120. At this time, the slurry is dropped on the polishing board 120. The polishing disk 120 and the slurry are set so that the polishing rate for the second ferromagnetic material 42 is high and the polishing rate for the first ferromagnetic material 41 (the first magnetic layer 22) is low. Since the first ferromagnetic material 41 and the second ferromagnetic material 42 are different, such setting can be performed.

  Therefore, as shown in FIG. 6F, the surface formed by the second magnetic layer 23 in the state of FIG. 6E is flattened, and finally, as shown in FIG. Then, the surface of the first magnetic layer 22 can be exposed, and the second magnetic layer 23 can be formed between the first magnetic layers 22. At this time, the master 20 in which the surface of the first magnetic material layer 22 and the surface of the second magnetic material layer 23 form the same plane, that is, the master 20 made of these materials has a flat surface.

  In the above manufacturing method, the first magnetic layer 22 is formed first (first film forming step: FIG. 6A), and then the first magnetic layer 22 is patterned (patterning step). 6B and FIG. 6C), the second magnetic layer 23 was formed later (second film forming step: FIG. 6E). However, the first magnetic layer 22 (the first ferromagnetic material 41) and the second magnetic layer 23 (the second ferromagnetic material 42) can be replaced with this example, and the above-described manufacturing method can be similarly performed. . The conditions for the flattening (FIGS. 6F and 6G) can be set accordingly. At this time, one of the first ferromagnetic material 41 and the second ferromagnetic material 42 which is easy to perform the above-described flattening treatment (FIGS. 6F and 6G) is formed later. (FIG. 6E), the other can be formed first and patterned (FIG. 6C). Alternatively, one of the first ferromagnetic material 41 and the second ferromagnetic material 42, which facilitates patterning (FIG. 6C), is first formed into a film and patterned (FIGS. 6A to 6C). (C)), and then the other can be formed into a film (FIG. 6E) and flattened (FIGS. 6F and 6G). That is, the order of film formation and the like can be appropriately set according to the types of the first ferromagnetic material 41 and the second ferromagnetic material 42.

  In the above manufacturing method, the patterns of the first magnetic layer 22 and the second magnetic layer 23 in FIG. 1 are determined by the photoresist layer 100 in FIG. The pattern of the first magnetic layer 22 having the width and the interval of 10 nm as described above can be easily realized by using the electron beam lithography. No subsequent lithography is required. Therefore, the master 20 can be manufactured at low cost by the above-described manufacturing method.

  Also, FIG. 6 shows a portion of the master 20 corresponding to the range of X in FIG. 8B, but the hatched area (or the unhatched area) in FIG. If the pattern of the photoresist layer 100 is formed in FIG. 8B, the master 20 corresponding to the entire pattern of FIG. 8B can be manufactured by the manufacturing method of FIG. That is, the master 20 corresponding to an arbitrary magnetic pattern can be manufactured by the above manufacturing method.

  In the state shown in FIG. 6 (g), the surface of the first magnetic layer 22 and the surface of the second magnetic layer 23 form the same plane, that is, the surface composed of these is completely flat. It was taken. In practice, it is difficult to make the surface composed of these completely flat, and it is not necessary that this surface be completely flat to obtain the above-mentioned effects. However, it is clear that the surface is preferably nearly flat. The required flatness depends on the minimum pattern width, and the smaller the minimum pattern width, the higher the required flatness. Here, the minimum pattern width means the minimum width of the pattern of the first magnetic layer 22 and the pattern of the second magnetic layer 23 in plan view. Specifically, the difference in height between the surface of the first magnetic layer 22 and the surface of the second magnetic layer 23 may be less than の of the minimum pattern width. For example, if the minimum pattern width is 10 nm, the height difference may be less than 5 nm. Such flatness can be realized by CMP. Even in such a case, it is possible to realize a state in which the master 20 and the slave 10 (the magnetic recording layer 12) are sufficiently close so that the state of FIG. 4C can be realized. Further, a technique other than CMP may be used for planarization.

  In the above example, it is assumed that the master 20 transfers the pattern of the servo signal to the slave 10. However, the master 20 transfers the magnetic pattern to any pattern to be recorded on the slave (magnetic recording medium). It is clear that a magnetic master and a magnetic pattern transfer method can be used in the same manner, whereby a magnetic recording medium on which this pattern (signal) has been transferred can be obtained at low cost. Further, it is clear that the above-described master for transferring a magnetic pattern and the method for transferring a magnetic pattern are also effective in manufacturing a magnetic encoder or the like using a predetermined magnetic pattern. That is, the magnetic recording medium used as the slave 10 is not limited to a magnetic recording medium used as a hard disk, and any medium on which a magnetic pattern is recorded can be used as the slave 10.

10 Slave (magnetic recording medium)
Reference Signs List 11 slave substrate 12 magnetic recording layer 12A inversion area 12B non-inversion area 20, 90 master (master for magnetic pattern transfer)
21 Substrate 22 First magnetic layer 23 Second magnetic layer 41 First ferromagnetic material 42 Second ferromagnetic material 90A Convex portion 90B Concave portion 100 Photoresist layer 110 Polishing jig 120 Polishing machine B0 Slave initialization magnetic field B1 Transfer magnetic field B2 Master initializing magnetic field B3 Bias magnetic fields B4, B5 Recording magnetic field M0 Initial magnetization M1 Rewriting magnetization M21, M22, M31, M32 Magnetization

Claims (8)

A magnetic pattern transfer master serving as a master for transferring a preset magnetic pattern to the surface of a magnetic recording medium,
A flat substrate,
A first magnetic layer made of a first ferromagnetic material and partially formed on the surface of the substrate in plan view;
A first ferromagnetic material which is formed of a second ferromagnetic material different from the first ferromagnetic material and is formed in a region other than a region where the first magnetic layer is formed on the surface of the substrate in plan view; A second magnetic layer having a different coercive force from the layer;
With
The difference in height between the surface of the first magnetic layer and the surface of the second magnetic layer is less than の of the minimum pattern width of the first magnetic layer and the second magnetic layer in plan view. A master for magnetic pattern transfer, characterized in that:   On the surface of the substrate, the other of the one magnetic layer and the second magnetic layer fills a space between one of the one magnetic layer and the second magnetic layer formed adjacent to the other. The magnetic pattern transfer master according to claim 1, wherein the master is formed so as to perform the following.   3. The magnetic pattern transfer master according to claim 2, wherein the surface of the first magnetic layer and the surface of the second magnetic layer exist on a common plane.   The magnetic pattern transfer according to any one of claims 1 to 3, wherein the first ferromagnetic material and the second ferromagnetic material are alloys containing Fe or Co, respectively. For master. A method for manufacturing a magnetic pattern transfer master according to claim 1, wherein:
A first magnetic layer forming step of forming the first magnetic layer on the substrate;
The second magnetic layer is formed such that a region where the first magnetic layer is not formed is buried in a region where the first magnetic layer is formed and a region where the first magnetic layer is not formed in plan view on the substrate. A second film forming step of forming a film of the ferromagnetic material;
The second ferromagnetic material on the first magnetic layer is removed to expose the first magnetic layer when viewed from above, and the second ferromagnetic material is removed to a region where the first magnetic layer is not formed. A planarization step of forming a magnetic layer,
A method for producing a magnetic pattern transfer master, comprising:   The method according to claim 5, wherein the flattening step is performed by chemical mechanical polishing. In the first magnetic layer forming step,
7. The magnetic pattern transfer according to claim 5, wherein after forming the first ferromagnetic material on the substrate, the formed first ferromagnetic material is partially removed. Method for manufacturing masters. A magnetic pattern transfer method using the magnetic pattern transfer master according to claim 1, wherein:
A slave magnetization step of uniformly magnetizing the surface of the slave as the magnetic recording medium in one direction along the normal direction of the slave,
By applying a master initialization magnetic field in the normal direction of the magnetic pattern transfer master, the magnetization of the surface of the magnetic pattern transfer master is uniformly applied in one direction along the normal direction of the magnetic pattern transfer master. A master magnetization step to
The surface of the master for magnetic pattern transfer after the master magnetization step is brought into contact with or close to the surface of the slave after the slave magnetization step, and one of the first magnetic layer and the second magnetic layer And a bias magnetic field which is smaller than the coercive force of the other of the first magnetic layer and the second magnetic layer and opposite to the master initializing magnetic field. A transfer process applied to the master,
A magnetic pattern transfer method, comprising:

Images