JPH10326718A - Paralleled magnetic field application structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized paralleled magnetic field application structure, with which the direction of the magnetic field of substrate surface can be made uniform in parallel in a highly precise manner. SOLUTION: A magnet 11, which generates a magnetic field in parallel with the magnetic thin film, is provided on the end of a substrate in this structure. The substrate 10 is arranged in parallel with the surface of the source of a magnetic material right above or right under the source of the magnetic material in this magnetic field application structure, and a pole piece 12 consisting of a ferromagnetic material is provided on the side facing to the substrate end of the magnet 11. The pole piece 12 is formed in such a manner that the thickness A of its center part is thinner than the thickness (B) of the other part. The form of the above-mentioned magnet 11 may be used in the same manner as in the case of the pole piece 12 instead of providing the pole piece 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a parallel magnetic field applying mechanism for forming a magnetic thin film.

[0002]

2. Description of the Related Art In recent years, in the field of magnetic recording, high-density recording has been progressing, and a magnetic head utilizing a magnetoresistive effect (hereinafter referred to as a magnetoresistive head) has been adopted for reproduction. Was.

As a method of forming the magnetic thin film for the magnetoresistive head, a vacuum film forming method such as a sputtering method or a vacuum evaporation method is used. For example, the sputtering device
As described in JP-A-62-109309, a ferromagnetic plate is arranged on the substrate surface and in the vicinity thereof, and a uniform magnetic field is passed through the substrate surface to make the film thickness distribution uniform. It is intended to form a magnetic thin film having a small variation in the direction of the axis of easy magnetization. That is, in the apparatus for forming such a magnetic thin film for a magnetoresistive head, as shown in FIG. 1 of the above-mentioned publication, the sputtering chamber includes a ferromagnetic target 1, a magnetron magnet 2, a leakage magnetic field of the magnetron magnet, and an applied external magnetic field. A ferromagnetic plate 4 for preventing a plasma state from being disturbed on a target surface by a magnetic field and for applying a magnetic field uniformly to the substrate 3 surface, and a Helmholtz coil for applying a uniform magnetic field to the substrate surface 5. FIG. 5 on page 58 of Electronic Materials, November 1994, also describes a magnetic thin film sputtering apparatus provided with a magnetic field applying mechanism that enables a uniform magnetic field to be applied using such a Helmholtz coil.

In a vacuum deposition apparatus, for example,
As described in Japanese Patent Application Laid-Open No. 5-339711, a magnet is arranged in close proximity to a substrate, and a magnetic field is generated along the deposition surface by the magnet so as to always face a fixed direction with respect to the deposition surface of the substrate. For this purpose, there is known a magnetic field application mechanism in which two rod-shaped magnets are mounted on a support plate on which the substrate is mounted at a position symmetrical with respect to a radial straight line passing through the center of the substrate and close to the substrate. I have.

[0005]

On the other hand, in order to increase the productivity of the magnetic head, the size of the substrate has been increased. As a result, not only the film thickness becomes uniform, but also the direction of the axis of easy magnetization of the formed magnetic thin film has to be changed. It is demanded that the same direction is directed at any position in the plane of the substrate.

However, in the sputtering apparatus, the size of the Helmholtz coil, which is a magnetic field generator for applying a magnetic field, increases with the increase in the size of the substrate, thereby increasing the size of the sputtering chamber and increasing the cost. is there.

Further, only two rod-shaped magnets are mounted at positions symmetrical with respect to a radial straight line passing through the center of the substrate and close to the substrate as in the above-mentioned vacuum vapor deposition apparatus.
A parallel magnetic field with a uniform direction cannot be obtained in the substrate plane,
There is a problem that variation in the direction of the easy axis of magnetization of the formed magnetic thin film cannot be sufficiently reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to reduce the size of a parallel magnetic field for forming a magnetic thin film as a magnetic field applying means capable of precisely aligning the direction of a magnetic field in a substrate surface in parallel. It is to provide a mechanism.

[0009]

A parallel magnetic field applying mechanism according to the present invention is a parallel magnetic field applying mechanism in which a magnet that generates a parallel magnetic field along a surface on which a magnetic thin film is formed on a substrate is disposed at an end of the substrate. Disposing the substrate directly above or below the magnetic material source in parallel with the surface of the magnetic material source, providing a pole piece made of a ferromagnetic material on the side of the magnet facing the end of the substrate, In the length direction perpendicular to the magnetic field direction, the thickness of the central portion is formed to be smaller than the thickness of other portions.

In the above-mentioned parallel magnetic field applying mechanism, instead of providing a pole piece, the magnet itself is formed such that the thickness of the center portion in the length direction perpendicular to the magnetic field direction is smaller than the thickness of the other portions. May be formed.

It is preferable that the magnet is a permanent magnet or an electromagnet, and the relative positional relationship between the substrate and the magnetic field does not change during the formation of the magnetic thin film. Further, it is desirable that the substrate is arranged in a plane at a position half the height of the magnet or the pole piece during the formation of the magnetic thin film.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings, but this is merely for explanation and does not limit the present invention in any way.

The two rod-shaped magnets are positioned symmetrically with respect to a radial straight line passing through the center of the substrate and close to the substrate so that the magnets facing the substrate end have different polarities. With only the arrangement, the magnetic field distribution on the film formation surface of the substrate has poor parallelism of the lines of magnetic force as shown in FIG. In this case, in order to generate a magnetic field with good parallelism, it is necessary that the length (L) of the magnet 1 is considerably larger than the diameter (D) of the substrate 2, for example, L / D is twice or more. is there. In FIG. 1, θ
Indicates an angle representing a position on the circumference. FIG. 2 shows the distribution of skew angles on the circumference of the circular substrate of FIG. As is clear from FIG. 2, the skew angle on the substrate circumference varies over a wide range, the maximum value also takes a large value, and the parallelism of the magnetic force lines on the deposition surface of the circular substrate becomes extremely poor depending on the position. You can see that it is.

On the other hand, the parallel magnetic field applying mechanism of the present invention, as shown in FIG. 3, generates a parallel magnetic field along the magnetic thin film forming surface of the substrate when depositing the magnetic material on the substrate 10. The magnets 11 are arranged at both ends of the substrate at positions symmetrical with respect to a radial straight line passing through the center of the substrate and close to the substrate, and the substrate is provided with a magnetic material source (not shown). And a pole piece 12 made of a ferromagnetic material disposed directly above or directly below the surface of the magnetic material source on the side of the magnet facing the substrate end. In the vertical length direction, it is formed so that the thickness (A) of the central portion is smaller than the thickness (B) of the other portions. Thus, as shown in FIG. 4, the parallelism of the lines of magnetic force on the deposition surface of the circular substrate is extremely good. In FIG. 4, θ indicates an angle representing a position on the circumference. FIG. 5 showing the distribution of skew angles on the circumference of the circular substrate (diameter D) of FIG.
As is clear from the figure, the magnetic field angle distribution is within the range of ± 1.00 °, and it is understood that the parallelism is good.

As the magnetic material source, targets or evaporation sources made of various materials used in a vacuum film forming method can be used.

As described above, the pole piece is formed so that the thickness at the center thereof is smaller than the thickness at other portions in the length direction perpendicular to the magnetic field direction, but this shape is particularly limited. However, the shape may be any shape as long as parallel lines of magnetic force can be formed. For example, the pole piece is formed so that the side facing the substrate end is stepped or inclined so that the thickness of the center portion is smaller than the thickness of the other portions, and the pole piece faces the substrate end. The surface on the side opposite to the side may be formed so as to be parallel to the surface of the facing magnet.

Instead of providing the pole piece, the magnet itself may be formed such that the thickness of the center portion thereof in the length direction perpendicular to the magnetic field direction is smaller than the thickness of other portions. In this case, the shape of the magnet is the same as that of the pole piece.

It is desirable that the substrate is disposed in the xz plane so as to be at a position half the height of the magnet or the pole piece during the formation of the magnetic thin film. FIG. 6 shows a case where the substrate is arranged in the xz plane at half the height of the magnet or pole piece (substrate X in the figure) and in the xz plane at the position of the end of the magnet or pole piece in the height direction. The positional relationship between the surface on which the magnetic thin film is formed and the lines of magnetic force is shown when a substrate is arranged (substrate Y in the figure). As is clear from the graph (FIG. 7) showing the relationship between Z / R and ATAN Bx / Bz for the substrates (X and Y) shown in FIG. 6, the height of the magnet or the pole piece is half the height. By arranging the substrate in the xz plane, the intended purpose is achieved.

The parallel magnetic field applying mechanism of the present invention can be applied to a known magnetic thin film forming apparatus, for example, a magnetic thin film forming apparatus used in a vacuum film forming method such as a sputtering method or a vacuum evaporation method.

[0020]

The parallel magnetic field applying mechanism according to the present invention is useful as a miniaturized magnetic field applying means capable of accurately aligning the directions of magnetic fields in a substrate plane in parallel.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing the direction of lines of magnetic force on a substrate by a conventional magnetic field generating means.

FIG. 2 is a graph showing a distribution state of a skew angle on a circumference of the circular substrate of FIG. 1;

FIG. 3 is a perspective view showing an embodiment of a parallel magnetic field applying mechanism of the present invention.

FIG. 4 is a plan view schematically showing directions of lines of magnetic force on a substrate by a parallel magnetic field applying mechanism of the present invention.

FIG. 5 is a graph showing a distribution state of a skew angle on a circumference of the circular substrate of FIG. 4;

FIG. 6 is a cross-sectional view schematically showing the relationship between the thin film formation surface and the magnetic field lines depending on the arrangement position of the substrate.

FIG. 7 shows Z / R and ATA for the substrate shown in FIG.
9 is a graph showing a relationship with NBx / Bz.

[Explanation of symbols]

1 magnet 2 substrate 10 substrate
11 Magnet 12 Polepiece A Thickness of the center of the polepiece B Thickness other than the center of the polepiece D Board diameter L Magnet length X Board
Y substrate

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Michi Kitahama, 2500 Hagizono, Chigasaki-shi, Kanagawa Japan Nippon Vacuum Engineering Co., Ltd.

Claims (5)

[Claims] 1. A parallel magnetic field applying mechanism in which a magnet that generates a parallel magnetic field along a magnetic thin film forming surface of a substrate is provided at an end of the substrate, wherein the substrate is located directly above or below a magnetic material source. A pole piece made of a ferromagnetic material is provided on the side of the magnet facing the substrate end, the pole piece being disposed parallel to the plane of the magnetic material source, and the pole piece is arranged in a length direction perpendicular to the magnetic field direction. A parallel magnetic field applying mechanism wherein a thickness of a central portion is formed smaller than thicknesses of other portions. 2. A parallel magnetic field applying mechanism in which a magnet for generating a parallel magnetic field along a surface of a substrate on which a magnetic thin film is formed is disposed at an end of the substrate, wherein the substrate is located directly above or below a magnetic material source. The magnet is disposed parallel to the plane of the magnetic material source, and the magnet is formed such that a thickness of a central portion thereof is smaller than a thickness of other portions in a length direction perpendicular to a magnetic field direction. Magnetic field application mechanism. 3. The parallel magnetic field applying mechanism according to claim 1, wherein the magnet is a permanent magnet or an electromagnet. 4. The parallel magnetic field applying mechanism according to claim 1, wherein a relative positional relationship between the substrate and the magnetic field does not change during the formation of the magnetic thin film. 5. The parallel magnetic field applying mechanism according to claim 1, wherein the substrate is disposed in a plane at a position half the height of the magnet or the pole piece during the formation of the magnetic thin film.