JP2004055023A - Orientated magnetic field generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an orientated magnetic field generator wherein a magnetic field is formed in the radial direction of a disk substrate, the easy magnetization axis of a magnetic layer is oriented in the radial direction, and no ununiform film thickness distribution caused by an oblique shadow effect. <P>SOLUTION: This orientated magnetic field generator is provided with a first magnet 12 inserted into the center hole 10A and a second magnet 14 arranged on the outer periphery of a substrate 10 used when a magnetic layer 2 is formed on the substrate 10 having the center hole 10A by a sputtering method, and magnetic poles on the opposing sides of the first and second magnets 12, 14 are opposite. A first auxiliary magnetic pole 13 is inserted between the first magnet 12 and the inner peripheral side of the substrate 10, a second auxiliary magnetic pole 15 is inserted between the second magnet 14 and the outer peripheral side of the substrate 10, and the first and second auxiliary magnetic poles 13, 15 are equal to the substrate 10 in thickness of the sides to be brought into contact therewith. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an orientation magnetic field generator, and more particularly, to a hard magnetic pinning layer, a soft magnetic underlayer and a perpendicular magnetic recording layer, and a hard magnetic pinning layer and a soft magnetic layer on a disk substrate. The present invention relates to an orientation magnetic field generator suitable for generating a magnetic field applied radially in a radial direction of a disk substrate and applied when forming an underlayer.
[0002]
[Prior art]
In magnetic recording, perpendicular recording is attracting attention because higher density recording is possible than in-plane recording.
Examples of the medium used in the perpendicular recording method (hereinafter, also simply referred to as a perpendicular recording medium) include a single-layer perpendicular recording medium having a single perpendicular recording layer (hereinafter, also simply referred to as a single-layer film medium) and a soft magnetic recording medium. A two-layer film perpendicular recording medium in which an underlayer and a perpendicular recording layer are stacked (hereinafter, also simply referred to as a two-layer film medium) and the like have been studied.
[0003]
The two-layer film medium can perform efficient magnetic recording / reproducing by combining with a single pole type head.
However, in the two-layer film medium, there is a known inconvenience that, after a signal corresponding to information is recorded, a recording magnetic field intensity is attenuated by a stray magnetic field. This is because the domain wall in the soft magnetic underlayer is likely to move due to the stray magnetic field, and the magnetic field generated by the domain wall movement erases the recording signal in the perpendicular recording layer. Further, the magnetic field generated by the domain wall movement of the soft magnetic underlayer may cause an increase in perpendicular magnetic recording medium noise (so-called spike noise).
[0004]
In order to prevent such deterioration of the recording signal and reduce medium noise, an in-plane oriented hard magnetic pinning having a remanent magnetization radially in the radial direction of the substrate is provided between the non-magnetic disk substrate and the soft magnetic underlayer. A structure in which a layer is provided has been proposed (for example, JP-A-5-258274 and JP-A-7-129946). The perpendicular magnetic recording medium having this structure has a three-layer structure including a perpendicular recording layer, a soft magnetic underlayer, and a hard magnetic layer (hard magnetic pinning layer) that fixes the magnetization direction of the soft magnetic underlayer in one direction. .
[0005]
[Problems to be solved by the invention]
Meanwhile, in a perpendicular magnetic recording medium (disk) having a three-layer structure capable of performing such high-density recording and stable against an external magnetic field, the hard magnetic pinning layer and the soft magnetic underlayer are radially oriented in the radial direction. Need to be done. As one of the methods, there is a method of forming a magnetic film by applying a magnetic field radially in the radial direction of the disk substrate. For example, there is a method utilizing a leakage magnetic field from a magnetron sputter target (for example, JP-A-5-258274). In addition, there is a method in which a magnet is provided at the center of a disk substrate and a film is formed in a radial magnetic field in a radial direction (for example, Japanese Patent Publication No. 4-73212).
[0006]
However, since the magnetic field distribution of the magnetron magnet disposed on the magnetron sputter target is generally distorted, a uniform magnetic field cannot be applied in the radial direction of the disk substrate.
On the other hand, when a magnet is provided at the center of the disk substrate, a strong radial magnetic field is obtained in the radial direction near the center of the disk substrate, but the magnetic field becomes weaker toward the outer periphery of the substrate, and the magnetic field strength at the outer periphery is reduced. Is not sufficient for the orientation of the magnetic layer.
[0007]
In order to solve this problem, as a conventional improvement, there has been proposed a method in which ring-shaped magnets are arranged on an inner peripheral portion and an outer peripheral portion of a disk substrate, and a magnetic field is applied in a radial direction of the substrate (for example, Japanese Patent Application Laid-Open (JP-A) no. 2001-209931).
FIG. 5 is a configuration diagram illustrating a conventional improved orientation magnetic field generator. 5A is a plan view, and FIG. 5B is an exploded perspective view.
As shown in these figures, in the orientation magnetic field generator 1, a ring-shaped magnet 12 'is arranged in the center hole 10A of the disk substrate 10, and a ring-shaped magnet 14' is It is arranged.
[0008]
The polarities of the ring-shaped magnets 12 ', 14' are, for example, as shown in the drawing, the S-pole inside the ring-shaped magnets 12 ', 14', the N-pole outside (or the opposite, the N-pole inside the ring-shaped magnets 12, and the outside, respectively). (S pole). Thereby, a magnetic field in the radial direction can be applied to the disk substrate 10.
Using this alignment magnetic field generator 1, a magnetic layer is formed on the disk substrate 10 by sputtering, and a magnetic layer oriented in the radial direction is obtained.
[0009]
However, in order to apply a magnetic field of a magnitude necessary to impart anisotropy to the hard magnetic pinning layer in the radial direction of the substrate, the ring-shaped magnets 12 ′ and 14 ′ must have a certain volume. In particular, a disk having a large disk diameter inevitably increases the interval between the magnets on the outer periphery and the inner periphery. In order to secure the volume of the magnet, it is necessary to increase the thickness of the ring-shaped magnet.
[0010]
The thickness of the disk substrate 10 varies depending on the disk size and the disk drive system, but generally ranges from 0.25 mm to 1 mm. Here, when the disk substrate 10 is arranged at the center of the magnet using a magnet of 3 mm with respect to the disk substrate 10 of thickness 0.6 mm, the magnet protrudes from the disk substrate by 1.2 mm on one side. Become.
FIG. 6 shows the state of formation of the magnetic film in this case.
FIG. 6 is a diagram for explaining the oblique effect in sputtering.
[0011]
FIG. 3 shows a state of the magnetic film 2 formed by sputtering when the ring-shaped magnet 14 ′ is arranged on the outer peripheral portion of the disk substrate 10.
When the ring-shaped magnets 14 ′ and 12 ′ having a rectangular cross section are used and the ring-shaped magnets 14 ′ and 12 ′ are arranged on the outer and inner circumferences of the disk substrate 10 so as to be almost in contact with the disk substrate 10, the magnetic film 2 is formed. At this time, the magnetic film 2 is less likely to adhere to the outer peripheral portion and the innermost peripheral portion of the disk substrate 10 due to the oblique effect, the thickness of the magnetic film 2A at the outer peripheral portion and the inner peripheral portion is reduced, and the overall film thickness distribution is reduced. There is a problem that a magnetic recording medium having uniform characteristics cannot be obtained with good yield.
[0012]
Therefore, the present invention solves the above-mentioned problem, forms a stable magnetic field of a constant strength in the radial direction of the disk substrate, orients the easy axis of the magnetic layer in the radial direction well, and makes the magnetic layer nonuniform due to the oblique effect. It is an object of the present invention to provide an alignment magnetic field generator that does not generate a large film thickness distribution.
[0013]
[Means for Solving the Problems]
As a means for achieving the above object, the present invention provides a method for forming a magnetic layer (magnetic film 2) by sputtering on a nonmagnetic substrate (disk substrate 10) having a center hole 10A. The first and second permanent magnets 12 include a first permanent magnet 12 inserted into the hole 10A and a second permanent magnet 14 disposed around the non-magnetic substrate (disk substrate 10). , 14 are arranged so that the magnetic poles on opposite sides thereof have opposite polarities.
A first auxiliary magnetic pole 13 is provided between the first permanent magnet 12 and the inner peripheral side of the non-magnetic substrate (disk substrate 10), and the second permanent magnet 14 and the non-magnetic substrate (disk substrate 10). A second auxiliary magnetic pole 15 is inserted between the first and second auxiliary magnetic poles 13 and 15 so that the thickness of the first and second auxiliary magnetic poles 13 and 15 on the side in contact with the non-magnetic substrate (disk substrate 10) is This is an alignment magnetic field generation device characterized in that it has the same thickness as the substrate (disk substrate 10).
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings by way of preferred examples. For the sake of simplicity of description, the same reference numerals are given to the same components as those of the conventional example, and the description is omitted.
[0015]
<First embodiment>
FIG. 1 is a configuration diagram showing a first embodiment of an alignment magnetic field generator according to the present invention.
1A is a plan view of the alignment magnetic field generator 1A, FIG. 1B is an exploded perspective view, and FIG. 1C is a cross-sectional view.
[0016]
As shown in these figures, in the alignment magnetic field generator 1A of the first embodiment, a ring-shaped permanent magnet 12 made of, for example, an SmCo-based rare earth magnet is arranged in a center hole 10A of a disk substrate 10, and a disk is formed. A ring-shaped permanent magnet 14 made of, for example, an SmCo-based rare earth magnet is arranged along the outer peripheral edge of the substrate 10. As shown in the drawing, the polarities of these ring-shaped magnets 12 and 14 are, for example, S-pole inside and N-pole outside the ring-shaped permanent magnets 12 and 14 (or N-pole inside, and S-pole outside). ). That is, the outside of the inner ring magnet 12 and the inside of the outer ring magnet 14 have opposite polarities, so that both polarities attract each other.
[0017]
A gap is provided between the ring-shaped permanent magnet 12 and the disk substrate 10, and a gap is provided between the ring-shaped permanent magnet 14 and the disk substrate 10, and the gap is provided with an auxiliary magnetic pole 13 made of a soft magnetic material and an auxiliary magnetic pole. 15 are arranged respectively. The auxiliary poles 13 and 15 are thinner than the ring-shaped permanent magnets 12 and 14 and have a thickness approximately equal to that of the disk substrate 10.
Therefore, a magnetic field having a sufficient intensity can be applied to the disk substrate 10 radially in the radial direction. When the disk substrate 10 is incorporated in the alignment magnetic field generator 1A, and the disk substrate 10 is placed in a pallet to be described later to form a magnetic layer by sputtering, a non-uniform film thickness distribution due to the oblique effect occurs on the disk substrate 10. There is no.
[0018]
<Second embodiment>
FIG. 2 is a sectional view showing a second embodiment of the alignment magnetic field generator according to the present invention.
As shown in the drawing, the orientation magnetic field generator 1B of the second embodiment is similar to the orientation magnetic field generator 1A of the first embodiment except that the auxiliary magnetic poles 16 and 17 are used instead of the auxiliary magnetic poles 13 and 15. The configuration is the same as that of the alignment magnetic field generator 1A of the first embodiment.
[0019]
In the auxiliary magnetic poles 16 and 17 made of a soft magnetic material, the thickness in contact with the permanent magnets 12 and 14 is substantially the same as the thickness of the permanent magnets 12 and 14, and the thickness in contact with the disk substrate 10 is reduced. The thickness is substantially the same as the thickness of the disk substrate 10. That is, the sectional shapes of the auxiliary magnetic poles 16 and 17 are trapezoidal. With such a cross-sectional shape, the magnetic flux from the permanent magnets 12 and 14 can be effectively introduced into the disk substrate 10.
Therefore, a magnetic field having a sufficient intensity can be applied to the disk substrate 10 radially in the radial direction. When the disk substrate 10 is incorporated in the alignment magnetic field generator 1B, and the disk substrate 10 is placed in a pallet to be described later to form a magnetic layer by sputtering, a non-uniform film thickness distribution due to the oblique effect is generated on the disk substrate 10. There is no.
[0020]
<Third embodiment>
FIG. 3 is a sectional view showing a third embodiment of the alignment magnetic field generator according to the present invention.
As shown in the figure, the orientation magnetic field generator 1C of the third embodiment includes a permanent magnet 20, a permanent magnet 22, a yoke 24, an auxiliary magnetic pole 18, and an auxiliary magnetic pole 19.
The permanent magnet 20 is made of, for example, an SmCo-based rare earth magnet, has a cylindrical shape having a diameter smaller than the diameter of the center hole 10A of the disk substrate 10, and has an upper pole at the N pole and a lower pole at the S pole (or On the contrary, the upper end face is magnetized to the S pole and the lower end face is magnetized to the N pole.
[0021]
The permanent magnet 22 is made of, for example, an SmCo-based rare earth magnet, has a ring shape having an inner diameter larger than the outer diameter of the disk substrate 10, and has the same height as the permanent magnet 20. The upper end surface of the permanent magnet 22 is magnetized to the S pole, and the lower end surface is magnetized to the N pole (or conversely, the upper end surface is magnetized to the N pole and the lower end surface is magnetized to the S pole).
The disk-shaped yoke 24 is made of a soft magnetic material, and a permanent magnet 22 is arranged on the outer periphery thereof, and a permanent magnet 20 is arranged at the center thereof.
[0022]
On the upper end surface of the permanent magnet 20, an auxiliary magnetic pole 18 made of a soft magnetic material, having a diameter smaller than the center hole 10A of the disk substrate 10, and having a thickness approximately equal to that of the disk substrate 10 is arranged.
The upper end surface of the permanent magnet 22 is made of a soft magnetic material, has an inner diameter larger than the outer diameter of the disk substrate 10, and has an outer diameter similar to the outer diameter of the permanent magnet 22. , A disk-shaped auxiliary magnetic pole 19 is disposed.
[0023]
With such a configuration, a radial magnetic field is generated radially from the outer peripheral portion of the auxiliary magnetic pole 18 toward the inner peripheral portion of the auxiliary magnetic pole 19, and the disk substrate 10 is disposed between the auxiliary magnetic poles 18 and 19. A magnetic field having a sufficient intensity can be applied to the disk substrate 10 in a radial manner in the radial direction.
When the disk substrate 10 is incorporated in the alignment magnetic field generator 1C, and the disk substrate 10 is placed in a pallet to be described later to form a magnetic layer by sputtering, a non-uniform film thickness distribution due to the oblique effect occurs on the disk substrate 10. Nothing.
In addition, as a material of the auxiliary magnetic poles 13, 15, 16, 17, 18, 19 and the yoke 24, a soft magnetic material having a high saturation magnetic flux density such as Fe, Co, Ni and an alloy containing these as a main component is preferable. .
[0024]
Next, a structure in which these alignment magnetic field generators 1A, 1B, and 1C are incorporated into a pallet of a sputtering apparatus will be described with reference to the alignment magnetic field generator 1A as an example.
FIG. 4 is an explanatory view showing a case where the first embodiment of the alignment magnetic field generator of the present invention is incorporated in a pallet. 4A is a plan view of the pallet 30, FIG. 4B is a plan view of the alignment magnetic field generator 1A incorporated in the pallet 30, and FIG. 4C is FIG. 4B. 4D shows a cross-sectional view of the line COD, and FIG. 4D shows an enlarged view of the portion A1 shown in FIG. 4B.
[0025]
As shown in these figures, the pallet 30 is formed with a plurality of insertion holes 32 for accommodating the alignment magnetic field generator 1A to which the disk substrate 10 is attached.
The permanent magnet 14 is fixed in the insertion hole 32 of the panel 30 by a holding plate 38 and a bolt 39 at three locations on the outer peripheral portion.
The auxiliary magnetic pole 15 is fixed to the permanent magnet 14 with an adhesive.
Notches 36 are provided at three locations on the inner peripheral portion of the auxiliary magnetic pole 15, and a non-magnetic leaf spring 34 is attached to the notches 36. This is shown in section A1, but the same applies to section A2 and section A3.
[0026]
The disk substrate 10 is inserted and arranged in the inner peripheral portion of the auxiliary magnetic pole 14, and the leaf spring 34 is held in close contact with the outer peripheral portion of the disk substrate 10.
An auxiliary pole 13 is inserted and held in the inner peripheral portion (center hole) of the disk substrate 10. Although not shown, a notch similar to the notch 36 is provided at three locations on the outer peripheral portion of the auxiliary magnetic pole 13, and a leaf spring similar to the non-magnetic leaf spring 34 is attached to the notch. Have been. The auxiliary magnetic pole 13 is held in the center hole 10A of the disk substrate 10 by this leaf spring.
The permanent magnet 12 is inserted into the inner peripheral portion of the auxiliary magnetic pole 13 and adhered and fixed with an adhesive.
[0027]
In this way, the alignment magnetic field generator 1A is mounted on the pallet 30, and a radial magnetic field having a predetermined strength is applied to the disk substrate 10 in the radial direction. The pallet 30 is formed by a magnetron sputtering device or the like. It is put into a film apparatus, and a hard magnetic pinning layer, a soft magnetic underlayer, and a perpendicular recording layer are formed on the disk substrate 10. That is, each magnetic layer can be formed while applying a magnetic field in the radial direction to the disk substrate 10 by the permanent magnets 12 and 14.
[0028]
The intensity of the magnetic field applied to the disk substrate 10 is set to a value that does not adversely affect the soft magnetic underlayer and the perpendicular recording layer while favorably orienting the easy axis of magnetization of the hard magnetic pinning layer in the radial direction. Thereby, the easy axis of magnetization of the hard magnetic pinning layer is favorably oriented in the radial direction, so that a perpendicular magnetic recording medium with less spike noise and good characteristics can be obtained.
The present invention is not limited to the above-described embodiment. For example, if a required magnetic field can be applied to the disk substrate, the magnet may be located on either the inner side or the outer side of the disk substrate. May be.
[0029]
【The invention's effect】
As described above, in the orientation magnetic field generator of the present invention, the first auxiliary magnetic pole is provided between the first permanent magnet and the inner peripheral side of the non-magnetic substrate, and the outer peripheral surface of the second permanent magnet and the non-magnetic substrate. A second auxiliary magnetic pole is inserted between the first and second auxiliary magnetic poles, and the first and second auxiliary magnetic poles are configured such that the thickness of the side in contact with the nonmagnetic substrate is equal to the thickness of the nonmagnetic substrate. A magnetic field of stable and constant intensity is formed in the radial direction of the disk substrate to easily orient the axis of easy magnetization of the magnetic layer in the radial direction, and to generate an alignment magnetic field that does not cause uneven thickness distribution due to the oblique effect. There is an effect that the device can be provided.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a first embodiment of an alignment magnetic field generator according to the present invention.
FIG. 2 is a sectional view showing a second embodiment of the alignment magnetic field generator according to the present invention.
FIG. 3 is a sectional view showing a third embodiment of the alignment magnetic field generator according to the present invention.
FIG. 4 is an explanatory view showing a case where the first embodiment of the alignment magnetic field generator according to the present invention is incorporated into a pallet.
FIG. 5 is a configuration diagram showing a conventional improved orientation magnetic field generator.
FIG. 6 is a diagram for explaining an oblique effect in sputtering.
[Explanation of symbols]
1, 1A, 1B, 1C: an alignment magnetic field generator, 2: magnetic film, 2A: magnetic film on the outer periphery, 10: disk substrate, 10A: center hole, 12: (ring-shaped) permanent magnet, 13: auxiliary magnetic pole , 14 ... (ring-shaped) permanent magnet, 15 ... auxiliary magnetic pole, 16 ... auxiliary magnetic pole, 17 ... auxiliary magnetic pole, 18 ... auxiliary magnetic pole, 19 ... auxiliary magnetic pole, 20 ... permanent magnet, 22 ... (ring-shaped) permanent magnet Reference numerals 24, yoke, 30 pallet, 32 insertion hole, 34 leaf spring, 36 notch, 38 holding plate, 39 bolt.

Claims (1)

A first permanent magnet inserted into the center hole and used for forming a magnetic layer by a sputtering method on a non-magnetic substrate having a center hole, and a second permanent magnet disposed around the non-magnetic substrate. In the orientation magnetic field generator, the first and second permanent magnets are configured such that the magnetic poles of the first and second permanent magnets facing each other have opposite polarities.
A first auxiliary magnetic pole is provided between the first permanent magnet and the inner peripheral side of the non-magnetic substrate, and a second auxiliary magnetic pole is provided between the second permanent magnet and the outer peripheral side of the non-magnetic substrate. The orientation magnetic field generator, wherein the first and second auxiliary magnetic poles are inserted, and the thickness of the first and second auxiliary magnetic poles on the side in contact with the nonmagnetic substrate is equal to the thickness of the nonmagnetic substrate.

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