JP2000030963A - Magnetic circuit for sputtering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic circuit for sputtering which can economically and easily be manufactured and makes it easy to adjust magnetic field parallelism after assembly. SOLUTION: This circuit consists of columnar magnets 1 which have positioning grooves on their outer peripheries along the length and are magnetized radially, a frame 3 which has storage holes for storing the columnar magnets 1 and positioning grooves provided adjacently to the storage holes, and positioning pins which are inserted into gaps formed of both grooves to position the columnar magnets 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an MR or GMR (Giant Magneto-Resi) for a hard disk.
The present invention relates to a sputter magnetic circuit used for imparting uniaxial magnetic anisotropy to a magnetoresistive element in a step of forming a magnetoresistive element such as a permalloy film of a magnetic recording head using a magnetic field (stand).

[0002]

2. Description of the Related Art When a magnetoresistive element is formed on a substrate by a sputtering method, it is necessary to apply a uniform magnetic field in a certain direction to the entire substrate in order to impart uniaxial magnetic anisotropy to the formed magnetoresistive element. . In this case, a conventional U-shaped or U-shaped permanent magnet 12 as shown in FIG.
A magnet-facing magnetic circuit supported by the above has been used. In this magnet-facing magnetic circuit, a uniform magnetic field in a certain direction is formed by combining a plurality of permanent magnets 12 having different shapes with slightly different magnetization directions (arrow directions in each magnet in FIG. 4).

[0003]

However, since such a magnet-facing magnetic circuit uses permanent magnets having different shapes, it is not easy to combine them so as to form a uniform magnetic field in a certain direction. It was not good in terms of cost. Moreover, partial disturbance in the direction of the magnetic field from the central axis, which may occur after assembly (magnetic field parallelism)
It was also difficult to adjust. SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic circuit for sputtering that can be manufactured economically and easily, and that can easily adjust the magnetic field parallelism after assembly.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventor has found that the above problem can be solved by using a dipole ring type magnet provided with a groove, and has completed the present invention. . That is, in the present invention, a plurality of radially magnetized cylindrical magnets having positioning grooves on the outer circumference along the longitudinal direction, a storage hole for storing the cylindrical magnet, and a storage hole provided adjacent to the storage hole are provided. A dipole ring type sputtering magnetic circuit, comprising: a frame having a plurality of alignment grooves; and a positioning pin for positioning a cylindrical magnet by being inserted into a gap formed by the two grooves. . In the present invention, it is preferable to dispose a yoke made of a magnetic material on the entire outer periphery of the frame or partially.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view showing an example of a magnetic circuit for sputtering according to the present invention, and FIG. 2 is an enlarged view of a part thereof. As shown in FIG. 1, the magnetic circuit of the present invention
A plurality of columnar magnets 1 whose magnetization directions are gradually changed are arranged to face each other symmetrically with respect to the central axis, and constitute a dipole ring type magnetic circuit. The dipole ring type magnetic circuit is a magnetic circuit in which the magnetization direction of the magnet gradually changes along the circumferential direction of the ring, and the magnetization direction rotates twice while making one rotation on the ring circumference. The number of the columnar magnets 1 may be determined according to the size of the magnetic circuit and the magnetic field specifications.
Often two rings constitute one ring. Thus, a magnetic field of N pole and S pole is generated in the internal space of the magnetic circuit, and a uniform in-plane magnetic field is generated in the radial direction.

As the cylindrical magnet 1 used in the present invention, only one type having the same shape may be used. Therefore, it is easy to manufacture the magnetic circuit of the present invention, and it is more cost effective than the conventional one. The shape of the cylindrical magnet 1 includes not only a cylindrical shape but also a disk shape and a cylindrical shape. However, in order to obtain a uniform magnetic field distribution directed in the radial direction inside the ring, a certain length in the longitudinal direction is required. On the outer periphery of the cylindrical magnet 1,
A positioning groove having a semicircular cross section is provided along the longitudinal direction. Similarly, a plurality of alignment grooves 4 having a semicircular cross section are provided adjacent to the storage holes of the frame 3. And
By positioning the positioning groove with the desired groove among the positioning grooves 4 with the cylindrical magnet 1 provided in the frame 3 and inserting the positioning pin 2 into a gap formed by both grooves, the cylindrical magnet 1 Can be fixed and positioned. For example, in FIG. 2, five positioning grooves 4 are provided, and the positioning grooves 4 are positioned in the second positioning groove 4 from the right. According to the present invention, by providing these grooves, it is possible to easily adjust the magnetic field parallelism, and as a result, a uniform magnetic field in a certain direction can be applied to the entire substrate. In particular, by making the diameters of both grooves as small as possible and providing a large number of positioning grooves 4, fine adjustment of the magnetic field parallelism becomes possible. It should be noted that a rare earth sintered magnet is used as the cylindrical magnet 1, and a samarium magnet having a good temperature characteristic or a heat-resistant neodymium magnet is preferable because of its heat resistance (about 200 ° C.).

The frame 3 is made of a non-magnetic material, and has a plurality of storage holes in which the columnar magnets 1 can be stored and grooves 4 for positioning the columnar magnets. It is preferable that the storage hole of the frame 3 be large enough to be able to rotate by inserting the columnar magnet 1 and to have as little air gap as possible. This is because if there is a gap, the magnetic flux leaks to the outside. However, it is acceptable to provide a gap due to the requirements of magnetic field adjustment and magnetic field distribution specifications.

The positioning pin 2 for fixing the cylindrical magnet by being inserted into the gap formed by the positioning groove and the positioning groove 4 may be made of a non-magnetic material such as aluminum. Further, the size of the positioning pin 2 is set to a size obtained by combining the positioning groove and the positioning groove 4.

The magnetic circuit of the present invention, as shown in FIG.
It is preferable to reduce the leakage magnetic flux by fixing and arranging the yoke 5 made of a magnetic material on the entire outer periphery of the frame 3 or partially (not shown). The yoke 5 is made of a magnetic material from the viewpoint of the saturation magnetization, the magnitude of the coercive force, the mechanical strength, the workability, and the cost, and examples thereof include materials such as sintered iron and low carbon steel. The yoke 5 can be fixed to the frame 3 by a method such as bonding.

[0010]

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

(Embodiment) As shown in FIG.
m, 16 cylindrical magnets having a length of 100 mm are inserted into the accommodating holes of the frame made of aluminum, and are arranged symmetrically with respect to the central axis.
A dipole magnetic circuit was constructed. As the cylindrical magnet, a sintered samarium magnet, R26HS (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) having a magnetic property of Br = 10.7 (kG) was used. And the positioning groove provided on the outer circumference of the cylindrical magnet,
The column was aligned with the positioning groove, and a positioning pin was inserted and fitted to fix the columnar magnet. A ring-shaped yoke having a width of 5 mm was fixed to the entire outer periphery of the frame using an iron-based SS400 material. A 6-inch substrate is arranged on the obtained dipole type magnetic circuit of the present invention, and the magnetic field intensity distribution on the circumference of the substrate at a position at a predetermined angle with respect to the central axis of the circuit and the deviation of the magnetic field direction from the central axis. The angle (magnetic field parallelism) was measured, and the results are shown in FIGS.

Comparative Example For comparison, see Japanese Patent Application Laid-Open No. 10-2
The same measurement as in the example was performed using a conventional magnet-facing magnetic circuit as shown in FIG. 4 described in US Pat. No. 7313, and the results are shown in FIGS.

(Evaluation) As can be seen from FIGS. 5 and 6, the magnetic circuit of the present invention has a magnetic field intensity distribution of about 5
0%, the magnetic field parallelism was improved from about 2.5 ° to within 1.0 °.

[0014]

The magnetic circuit of the present invention can be manufactured economically and easily, and the adjustment of the magnetic field parallelism after assembly is easy.
Suitable for applying a uniform magnetic field to the substrate.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a magnetic circuit for sputtering according to the present invention.

FIG. 2 is an enlarged view of a part of a magnetic circuit for sputtering according to the present invention;

FIG. 3 is a cross-sectional view showing an example of a magnetic circuit for sputtering according to the present invention in which a yoke is provided on the outer periphery of a frame.

FIG. 4 is a cross-sectional view of a conventional magnet-facing magnetic circuit.

FIG. 5 is a diagram illustrating magnetic field strengths of an example and a comparative example.

FIG. 6 is a diagram illustrating the magnetic field parallelism of an example and a comparative example.

[Explanation of symbols]

 Reference Signs List 1 cylindrical magnet 2 positioning pin 3 frame 4 positioning groove 5, 11 yoke 12 permanent magnet

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[Procedure amendment]

[Submission date] July 21, 1998 (7.27.2
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

(Evaluation) As can be seen from FIGS. 5 and 6, the magnetic circuit of the present invention has a magnetic field intensity distribution of about 5
0%, the magnetic field parallelism was improved from about 2.5 ° to within 1.0 ° .

Claims (4)

[Claims] 1. A plurality of radially magnetized cylindrical magnets having positioning grooves on the outer circumference along a longitudinal direction, a plurality of storage holes for storing the cylindrical magnets, and a plurality of storage holes provided adjacent to the storage holes. A dipole ring-type magnetic circuit for sputtering, comprising: a frame having the positioning grooves described above; and a positioning pin for positioning the cylindrical magnet by being inserted into a gap formed by the two grooves. 2. The sputter magnetic circuit according to claim 1, wherein a yoke made of a magnetic material is provided on an outer periphery of the frame. 3. The magnetic circuit for sputtering according to claim 2, wherein the yoke is disposed on the entire outer periphery of the frame. 4. The magnetic circuit for sputtering according to claim 2, wherein the yoke is partially disposed on the outer periphery of the frame.