JPH0298112A - Manufacture of soft magnetic thin film - Google Patents

Abstract

PURPOSE:To restrain the growth of crystal grains and realize low coercive force and high permeability easily by a method wherein, when a soft magnetic thin film is formed by a sputtering process, 2-30% of oxygen is periodically led in the sputtering atmosphere. CONSTITUTION:The oxygen partial pressure led in sputtering atmosphere is specified to be 3-20% of the whole atmospheric gas. That is, if the oxygen partial pressure does not exceed 3%, the magnetic characteristics can not be enhanced due to the less led-in amount of oxygen but if the oxygen partial pressure exceeds 20%, the effective permeability of soft magnetic thin film declines notably. Since the oxygen is only to be led periodically in the sputtering atmosphere, a laminated soft magnetic thin film formed in an atmosphere comprising either argon only or oxygen and argon suffices. Through these procedures, the constitution of device can be simplified by the restraint of crystal grain deposition, the enhancement of permeability and the formation of the soft magnetic thin film by the simple modulation of sputtering atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a soft magnetic thin film useful as a core material of a magnetic head.

[Summary of the Invention] The present invention provides a method for forming a soft magnetic g thin film by sputtering in a sputtering atmosphere at appropriate intervals. Increasing the density and frequency of signals is progressing, and in response to this increase in recording density, Fe is used in magnetic powder as a magnetic recording medium.

Powders of ferromagnetic metals such as Co and Ni were used. A so-called metal tape or a ferromagnetic metal material was directly deposited on the base film by a method such as vapor deposition. So-called vapor deposition tapes and the like are being put into practical use.

Since this type of magnetic recording medium has a high coercive force, the core material of the magnetic head used for recording and reproducing is required to have a high saturation magnetic flux density. For example, ferrite materials, which have conventionally been widely used as core materials for magnetic heads, lack saturation magnetic flux density and are difficult to cope with increasing coercive force.

For this reason, conventionally, in order to support these high coercive force magnetic recording media, soft magnetic films with high saturation magnetic flux density are deposited on non-magnetic substrates such as ceramics or magnetic substrates such as ferrite, and these soft magnetic films are bonded together. A so-called metal-in-gap type magnetic head in which magnetic heads are butted together to form a magnetic gap, and a 111g magnetic head in which a soft magnetic film or a conductive thin film has a multilayer structure with an insulating film interposed therebetween have been proposed.

The soft magnetic films used in the above-mentioned metal-in-gap magnetic heads and thin-film magnetic heads include Fc-Al-3i alloy magnetic films that are thermally stable and have a high saturation magnetic flux density, and even better. Fe-Ga- exhibits soft magnetic properties.
3i alloy magnetic films are known.

However, these soft magnetic radiators require a certain film thickness in order to obtain magnetic flux compatible with high coercive force magnetic recording media, but as the film thickness increases, eddy current (1) loss increases and crystal grain growth occurs. etc. will also become large. As a result, the magnetic properties (eg, magnetic permeability) of the soft magnetic film deteriorate, resulting in a reduction in the reproduction output of the magnetic head, making it impossible to achieve high-density recording, that is, short-wavelength recording.

Generally, it is known that one method of improving magnetic properties by preventing eddy current loss and crystal grain growth is to form a soft magnetic film into a multilayer structure with an insulating film or a metal film interposed therebetween.

However, although the permeability of the laminate is restored by decreasing the thickness of each layer of the soft magnetic film, the appearance of the laminate as a whole is The saturation magnetization of decreases. Furthermore, when the non-magnetic materials are located parallel to the magnetic gap, these non-magnetic materials act as a spurious gap, causing undulations in the frequency characteristics.

Therefore, as previously disclosed in Japanese Patent Application No. 63-99507, etc., the applicant of the present invention secured high magnetic permeability while laminating an oxide magnetic thin film as a magnetic material and a soft magnetic film 11. proposed a soft magnetic thin film that also improves the saturation magnetic flux density of the entire laminated film.

[Problem to be solved by the invention]

However, in order to form a soft magnetic thin film with a laminated structure of the above-mentioned soft Ml thin film and oxide thin film, an alloy target for sputtering the soft magnetic thin film and an oxide magnetic thin film are sputtered in the same chamber. Both alloy targets must be installed, which complicates the equipment configuration. Also,
Since both the soft magnetic thin film and the oxide magnetic thin film are sputtered, the process becomes complicated and productivity cannot be improved.

Therefore, the present invention has been proposed in consideration of the conventional situation, and makes it possible to achieve low coercive force and high magnetic permeability while ensuring high saturation magnetic flux density, and has a simple device configuration. The object of the present invention is to provide a method for manufacturing a soft magnetic thin film with excellent productivity.

[Means for Solving the Problem] As a result of extensive research over a long period of time in order to achieve the above-mentioned object, the present inventor discovered that oxygen is added at appropriate intervals to the sputtering atmosphere when laminating soft magnetic thin films. The present invention was completed based on the discovery that the introduction of the above is extremely effective in improving magnetic properties.

That is, the method for producing a soft magnetic thin film of the present invention is characterized by periodically introducing 3 to 20% oxygen into the sputtering atmosphere when forming the soft magnetic thin film by sputtering.

As the target soft magnetic mH, for example, FeGa-3i
Examples include soft magnetic thin films. The composition range of Fe and GaSi contained in this FeGa-3i soft magnetic thin film is as follows:
Ga content is 1-23% by weight, Si content is 9-31%
It is preferable that the balance by weight is Fe. That is,
When the above-mentioned Fe-Ga-3i-based soft magnetic thin film is Fe, Ga, SIc (a, b, c represent the weight ratio of each component), the composition range is 68≦a≦84 1≦ b≦23 9≦C≦31 a+b+c=Io.

It is desirable that If the amount of Ga or Si is too little, or too much, the magnetic properties will deteriorate.

Further, it is also possible to replace a part of the above Fe with Co. By replacing a portion of the Fe with Co, the saturation magnetic flux density can be increased.

The IAffi of this Co is 0 to 2 for Fe.
It is preferably within the range of 0% by weight.

Furthermore, various elements may be added as additives to the above-mentioned Fe-Ga-3i-based soft magnetic thin film in order to further improve wear resistance and soft magnetic properties. Elements used as the additives include Ti CrMn, Zr, Nb, Mo,
'a, W, Ru, 0sIr, Re, Ni, Pd, PL
, Hr, V or a combination of two or more 0
．． It is added in a range of 5 to 6.0% by weight. That is, the above additive is M, and the Fe-C; a-5i soft magnetic thin film is expressed by the formula %.
When expressed in formula % (a, b, c, d, e represent the weight ratio of each component), the composition range is 6 days≦a≦84 0≦b≦15 1≦C≦23 6≦ It is desirable to satisfy d≦31 0.5≦e≦6.0. If the amount of the additive added exceeds a predetermined range, the magnetic properties will deteriorate.

In addition, in each composition formula mentioned above, a part of Ga is AIV.

Alternatively, a part of Si may be substituted with Ge.

In addition to the Fe-Ga-3i soft magnetic thin film described above, it is also possible to use, for example, a crystalline ferromagnetic material L14 containing Fe as a main component. Specifically, Fe-Af-3
i-based soft magnetic 7 thin film, Fe-Δβ-based soft magnetic thin film, Fe-3
i-based soft magnetic thin film, Fe-Aj! Examples of the Ge-based soft magnetic film include soft 651+'1 thin film in which a part of Fe in the soft stone film 119 is replaced with Co.

On the other hand, the oxygen partial pressure introduced into the sputtering atmosphere is set to 3 to 20% of the total atmospheric gas. That is, if the oxygen partial pressure is 3% or less, the amount of oxygen introduced is too small to improve the magnetic properties.

Furthermore, if the oxygen partial pressure exceeds 20%, the effective magnetic permeability of the soft magnetic thin film will drop significantly. Note that the oxygen partial pressure is more preferably 5 to 10% in order to improve magnetic properties.

For example, argon gas can be used as the sputtering atmosphere.

Further, as for the cycle of introducing oxygen, for example, the thickness of a film sputtered in an argon atmosphere is about 100 to 1 μm, and the thickness of a film sputtered in an atmosphere consisting of argon and oxygen is about 50 to 1 μm. This is desirable. Furthermore, the number of laminated layers sputtered in these atmospheres is preferably 4 to 20 layers.

Since the oxygen introduced into the sputtering atmosphere can be introduced periodically, the laminated soft magnetic thin films can be formed in a sputtering atmosphere consisting only of argon or in a sputtering atmosphere consisting of oxygen and argon. Not only a soft magnetic thin film, but also a laminated soft magnetic 7iJII film always formed in a sputtering atmosphere consisting only of oxygen and argon! It may be 2. For example, a sputtering atmosphere consisting of argon and 3% oxygen.

An example is a sputtering atmosphere consisting of argon and 15% oxygen.

In this case, the oxygen partial pressures are 3-15% and 8-2, respectively.
It is preferable to set it to 0%, and moreover, it is desirable that the difference in oxygen partial pressure is set to 5%.

The soft magnetic thin film manufactured by the method of the present invention can be applied to a so-called metal-in-gear type magnetic head in which the soft magnetic thin film is interposed on the abutting surfaces of the head cores. For example, a magnetic head where the abutting surface is formed parallel to the magnetic gap, or the abutting surface is cut out diagonally, a soft magnetic thin film is deposited on this slope, and a magnetic gap is formed at the abutting surface between these diagonal films. Examples include magnetic heads made of

[Effect]

In the present invention, when a soft magnetic thin film is formed by sputtering or taring, a predetermined amount of oxygen is periodically introduced into the sputtering atmosphere, which suppresses the growth of crystal grains and improves magnetic permeability. do.

In addition, in the present invention, since the composition modulation is between soft magnetic thin films and does not include a non-magnetic part, there is no leakage of magnetic flux from the magnetic film even if the composition is modulated in the direction perpendicular to the magnetic gap. The occurrence of is suppressed.

Furthermore, in the present invention, since the soft magnetic thin film is formed simply by modulating the sputtering atmosphere, there is no need to increase the number of targets, which simplifies the device configuration and also simplifies the manufacturing process. .

[Example] Specific examples to which the present invention is applied will be described below.
It goes without saying that the present invention is not limited to these examples.

First, Fe, Gab Sic Run alloy (&[l composition is atomic %: a = 62.5.b = 10.5.c = 19.d-
8) as a target, and 4) as a reaction prevention film in advance.
After forming a 0.5 μm film of an alloy having the above composition in an argon atmosphere on a ferrite core block on which 5 and 4 pts were formed, 10% oxygen was introduced into the argon atmosphere to form a film consisting of argon and 10% oxygen. An alloy having the above composition was also formed into a film in a sputtering atmosphere to a thickness of 500. Then, these steps were repeated to form a film in an argon atmosphere.
Eight layers of 5μIn thick films were stacked so that between each layer of the 0.5μm Ti film there was a 500mm thick film formed in a sputtering atmosphere consisting of argon and 10% oxygen. Sputtering was performed so that the thickness was 4 μm.

Next, the resulting laminated film was annealed at 550°C in vacuum, and its magnetic properties were measured, and the coercive force was 0.080e (Oersted).

Effective magnetic permeability is 4000-5000 (value at 5Mllz)
.

The saturation magnetic flux density was IIKG.

Incidentally, the temperature of the above-mentioned annealing treatment is a value that allows glass fusing using normal magnetic bonding.

Furthermore, when the above soft magnetic thin film was actually used as the core material of a magnetic head and the reproducing output of the iNiff magnetic head was measured, it was found that magnetic ld compared to the playback output of the head.
An improvement of B or higher was observed.

Using the same target as in Example 1, a ferrite core block on which 45% of PT was deposited in advance as a reaction prevention film was coated with the above composition in a sputtering atmosphere consisting of argon and 10% oxygen. A single-layer soft magnetic thin film was formed to have a thickness of 4 μm.

Then, after annealing under the same conditions as in Example 1, the magnetic properties were measured, and the coercive force was approximately 0.
．． 70 e, the effective permeability was about 1200 (value at 5 MIIz), and the saturated 6d flux density was about 10.2 K G.

Using the same target as in Example 1, an alloy having the above composition was applied to a ferrite core block on which a PT of 45% was deposited in advance as a reaction prevention film in a sputtering atmosphere consisting only of argon. A single-layer soft magnetic thin film was also formed to have a thickness of 4 μm.

Similarly, after annealing the obtained soft magnetic thin film, the magnetic properties were measured, and the coercive force was 1. O
Oe, effective magnetic permeability is approximately 800 (value at 5 MIIz),
The saturation magnetic flux density was IIKG.

Said Example 1. Comparative example 1. The magnetic properties of Comparative Example 2 are summarized in Table 1.

As can be seen from Table 1 above, the single layer film formed in an argon atmosphere is significantly inferior in terms of coercive force 5 effective permeability,
Furthermore, in a single layer film sputtered in an argon atmosphere containing 10% oxygen, a slight decrease in coercive force and improvement in effective magnetic permeability were observed, but a decrease in saturation magnetic flux density was observed.

On the other hand, when oxygen is introduced into an argon atmosphere one by one, and a +12 411-layer structure is formed in an argon atmosphere and an argon atmosphere containing oxygen, the saturation magnetic flux density does not decrease. Therefore, an extremely low coercive force can be obtained without any problems, and an extremely high effective magnetic permeability can be obtained.

Therefore, by periodically introducing oxygen into an argon atmosphere to form a laminated film structure, a low coercive force and high magnetic permeability can be achieved, and a soft magnetic thin film with extremely excellent soft magnetic properties can be obtained.

Therefore, if the soft magnetic thin film to which the method of the present invention is applied is used as the core material of a magnetic head, the output can be improved, the output decreases less even in high frequency bands, and it can be used with higher coercive force magnetic recording media. .

Furthermore, according to the soft magnetic thin film, since the composition is modulated between soft (R) thin films, it does not contain any non-magnetic elements, and even if the composition is modulated in the direction perpendicular to the magnetic gap, magnetic flux leaks from within the metal film. There is no pseudo gear, and it does not operate as a gear.

Furthermore, even if the thickness of the soft magnetic thin film is increased to ensure sufficient magnetic flux, the growth of crystal grains is suppressed because oxygen is introduced into the sputtering atmosphere. Magnetic properties of il film (
In particular, the magnetic permeability does not deteriorate.

(Effects of the Invention) As is clear from the above explanation, according to the method of the present invention, oxygen is introduced circumferentially into the sputtering atmosphere when forming a soft magnetic thin film. Growth can be suppressed, and low coercive force and high i3 magnetic rate can be easily achieved.

In addition, since the soft magnetic thin film obtained by applying the method of the present invention is different in texture from the soft magnetic thin film that has a non-magnetic film interposed therebetween, it is possible to ensure a high saturation magnetic flux density, and the magnetic properties remain unchanged even when the film thickness is increased. No deterioration. In addition, even if the composition is modulated in the direction perpendicular to the 651 air gap, there is no leakage of magnetic flux from within the metal film.
It does not operate as a pseudo gap.

Further, according to the method of the present invention, since film formation is performed only by modulating the sputtering atmosphere, conventional sputtering equipment can be used, and the manufacturing process is simplified, leading to improved productivity.

Therefore, when a soft magnetic thin film obtained by applying the method of the present invention is used as a core material of a magnetic head, it exhibits high output up to a high frequency band and exhibits good recording characteristics for a high coercive force magnetic recording medium.

Claims (1)

[Scope of Claim] A method for producing a soft magnetic thin film, which comprises periodically introducing 3 to 20% oxygen into the sputtering atmosphere when forming the soft magnetic thin film by sputtering.