JPH07235419A - Magnetic thin film and magnetic recorder using the same - Google Patents

Abstract

PURPOSE:To improve corrosion resistance while maintaining soft magnetic characteristics by controlling a film growing atmosphere and/or film growing conditions, and controlling a structure and magnetic characteristics of a crystallographic film of the thin film. CONSTITUTION:In the case of manufacturing a soft magnetic thin film, a film growing atmosphere and/or film growing conditions are controlled thereby to control a crystallographic structure and magnetic characteristics of the thin film. The control of the atmosphere uses a mixed gas atmosphere containing 0.1 to 30vol.% of at least one type of gas selected from Ar, N2, Xe, Rn, Ne, and Kr except mother gas in a gas atmosphere containing AR or N2 as a main component. On the other hand, the controlled conditions have a pressure of discharge gas, RF power to be applied, a distance between a board and a target, a board temperature, a board moving type, etc. The structure of the thin film is at least one of a bulk density, am internal stress, and a crystal grain size of the film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a magnetic thin film having soft magnetic characteristics, a magnetic thin film and a magnetic head manufactured using the same, and a magnetic recording apparatus using the same, and particularly to high reliability. And a method of manufacturing the magnetic film, and a magnetic head using the same,
The present invention relates to a magnetic recording device.

[0002]

2. Description of the Related Art With the progress of the advanced information society in recent years, there is an increasing need for a compact and high-density storage device. Among them, studies on high-density recording and downsizing of magnetic recording devices are being rapidly advanced. In order to realize high-density recording, a medium having a high coercive force and a high-performance magnetic head capable of recording on this medium are required in order to allow recorded fine magnetic domains to stably exist. In order to sufficiently magnetize the high coercive force medium to record a signal, a magnetic head material having a high saturation magnetic flux density capable of generating a strong magnetic field is required. At present, Fe-C-based materials, Fe-N-based materials, and the like are known as materials having a proposed high saturation magnetic flux density. However, when these materials are used for a magnetic head, they react with oxygen and water in the atmosphere to generate hydroxides and oxides, and magnetic properties, in particular, change in coercive force and saturation magnetic flux density, The performance of the magnetic head was sometimes degraded. Therefore, in putting a magnetic head using this material into practical use, it has been a problem to suppress variations in these magnetic characteristics. Therefore, it has been proposed to add an element for improving the corrosion resistance in addition to the magnetic element. As a known example thereof, Japanese Patent Laid-Open No. 3-20444 can be mentioned.

[0003]

In the above-mentioned known examples, it is sometimes difficult to achieve both the magnetic characteristics optimized by the addition of elements and the compositional adjustment and the added element concentration necessary for improving the corrosion resistance. That is, if corrosion resistance is secured, magnetic characteristics,
In particular, since the saturation magnetic flux density and the coercive force are deteriorated and the performance of the magnetic head is deteriorated, it may cause an error or noise when recording, which may be a limit to the improvement of corrosion resistance.

The object of the present invention is to improve the corrosion resistance of a soft magnetic thin film mainly composed of Fe having a high saturation magnetic flux density while maintaining its soft magnetic characteristics, thereby providing a magnetic material having high performance and high reliability. It is an object of the present invention to provide a manufacturing method for obtaining a thin film, a high performance magnetic head using the soft magnetic thin film, and a magnetic recording apparatus using the same.

[0005]

In order to achieve the above object, the present invention provides a magnetic thin film by controlling a film forming atmosphere and / or film forming conditions in a process of manufacturing a magnetic thin film having at least soft magnetic characteristics. It is effective to control the crystallographic film structure and magnetic properties of the. Ultimately, the crystal grain size formed after film formation is controlled. In that case, the film quality immediately after film formation is particularly important.

A magnetic head must have a magnetic film formed on a substrate having unevenness on the surface. In that case, the bulk density, crystal grain size, or internal stress of the magnetic film formed varies depending on the location of the substrate. As a result, the magnetic characteristics of the magnetic film may be deteriorated or the corrosion resistance may be deteriorated. In order to suppress this, by controlling the film forming atmosphere and / or the film forming conditions, it is possible to always form a uniform magnetic film without depending on the shape of the substrate surface, resulting in high performance and high reliability. The obtained magnetic film is obtained. By this method, the bulk density, internal stress, or crystal grain size can be controlled, and at the same time, the structure of the magnetic thin film in the film thickness direction can be controlled.

Here, the control of the film forming atmosphere means that a gas mainly containing Ar or N ₂ is used as an atmosphere gas, and is selected from Ar, He, Kr, Rn and N ₂ other than the mother gas. A gas to which at least one kind of gas described above is added may be used. On the other hand, the film forming conditions to be controlled are the discharge gas pressure,
The input RF power, the substrate-target distance, the substrate temperature, the substrate moving method, and the like. Among them, the pressure of the discharge gas and the input RF have a great influence on the quality of the formed film.
Power.

The material used for the magnetic film is at least Fe in a concentration range of 5 at% to 20 at% and C in an amount of 1 a.
Mainly composed of materials contained in the concentration range of t% to 20 at%, and at least α-Fe by a microcrystal precipitation reaction after film formation.
The magnetic thin film in which the phase and the TaC phase are precipitated is most preferable. In addition, the same effect can be obtained when N or B is used instead of C.

The crystal grain size of each phase of the film thus formed is most preferably 10 nm or more and 25 nm or less for the α-Fe phase and 10 nm or less for the TaC phase. In addition to the above magnetic elements, in order to further improve the corrosion resistance and thermal stability of the magnetic film, in addition to the magnetic elements, N,
At least one element selected from Al, C, Nb, Ti, Cr, Ru, Rh, and Zr may be contained.
In this case, the added element is a part included in the Fe phase,
Carbide represented by TaC or the like, a nitride layer, and a portion contained as a compound in the boride phase.

As the magnetic thin film having this soft magnetic characteristic,
In a magnetic thin film mainly composed of Fe, Ta, and C or N, an alloy thin film containing a plurality of elements having different free energies of reaction with carbon or nitrogen and different solid solution rates to Fe is further heated. The treatment is performed to precipitate fine crystals, and the free energy of reaction with carbon or nitrogen is large at the grain boundaries, and the element having a small solid solution rate with Fe is precipitated, and the free energy of reaction with carbon is small, and Fe
It is preferable that the element having a higher solid solution rate be present as an alloy in the Fe microcrystalline phase.

As the film forming method used for forming the thin film, the greatest effect can be obtained when the sputtering method, the ion plating method, the electron beam evaporation method, or the ion beam evaporation method is used.

The soft magnetic thin film thus manufactured is used to manufacture a magnetic head, which is preferably used in a magnetic recording apparatus for recording information on a moving information recording medium by using magnetic properties. Is. The magnetic head using this soft magnetic thin film is most preferably a metal in-gap type magnetic head. The head is not limited to this type, and a head having any structure may be configured.

In the manufacture of the magnetic head using the above soft magnetic thin film, when a substrate having unevenness on the surface is used as a substrate and the magnetic film is manufactured on the substrate using the above manufacturing process, Even if the flight angles of sputtered particles are different, it is possible to always form a soft magnetic film having a uniform structure. As a result, it is possible to obtain a magnetic film having excellent uniformity and magnetic properties. In addition, since the crystal grain size can be controlled to a certain size or less, a soft magnetic thin film having higher corrosion resistance can be obtained.

In order to further increase this effect, a layer for controlling the adhesion between the magnetic thin film and the substrate and / or the crystallographic and magnetic orientation of the thin film prior to the production of the above-mentioned soft magnetic thin film. Should be provided. As a layer provided for that, Cr, Ta, Nb, CoTaZr alloy, CoNb
It is preferable that at least one kind of thin film selected from Zr alloy, silicon oxide, silicon nitride, W, Mo, and Al is formed, and the film thickness is 100 nm or less. Such an effect is obtained when the soft magnetic thin film is formed and / or in a film forming atmosphere.
Alternatively, since the crystallographic structure and magnetic properties of the magnetic thin film can be controlled by controlling the film forming conditions, the soft magnetic thin film is chemically or electrochemically mixed with water and / or oxygen. This is because various reactivity can be controlled.
Furthermore, the cross section and the surface of the soft magnetic thin film can be made to have equal chemical or electrochemical reactivity with water and / or oxygen.

[0015]

According to the above method, the crystallographic structure and magnetic characteristics of the magnetic thin film can be controlled by controlling the atmosphere and conditions for producing the magnetic film. This is the bulk density of the membrane,
This is because the structure of the magnetic thin film can be controlled by controlling at least one of the internal stresses. Furthermore, in the production of a magnetic head using a soft magnetic thin film, when a substrate having irregularities on the surface is used as a substrate and a magnetic film is produced on the substrate using the above production process, sputtered particles are generated on the substrate surface. Even if the flight angles are different, it is possible to always form a soft magnetic film having a uniform texture independent of the location of the substrate. This is because the kinetic energy of sputtered particles can be controlled by controlling the atmosphere and conditions under which the magnetic film is produced.

In the production of the soft magnetic thin film, by controlling the film forming atmosphere and / or the film forming conditions,
The crystallographic structure and magnetic properties of the magnetic thin film can be controlled. This makes it possible to obtain a magnetic film having excellent soft magnetic characteristics. By these methods, the crystal grain size can be controlled to be a certain size or less, so that it has good soft magnetic properties and, at the same time, is effective in improving the corrosion resistance. By controlling the crystal grain size of the magnetic film, it is possible to control the chemical or electrochemical reactivity of the soft magnetic thin film with water and / or oxygen. Further, if a layer for controlling the adhesion between the magnetic thin film and the substrate and / or the crystallographic and magnetic orientation of the thin film is provided prior to the production of the magnetic film, the effect is further improved. This is because the controllability of the crystal grain size is improved.

[0017]

【Example】

(Example 1) The magnetic thin film used in this example is FeTaC.
This is an example using a CrNb alloy film. The film formation was performed using the sputtering method. A ferrite substrate having uneven grooves on its surface was used. FeTaC is used as the sputtering target.
A CrNb alloy target was used and Ar was used as the discharge gas. Discharge gas pressure: 15 mTorr, input RF power: 30
Sputtering was performed with a 0 W / 5 ″ target. The thickness of the formed magnetic film was 10 μm. The magnetic film thus produced was heat-treated at 600 ° C. for 1 hour in an Ar stream.

As a comparative example, using the same alloy target, discharge gas pressure: 6 mTorr, input RF power: 500
The same heat treatment was performed on the magnetic film sputtered with the W / 5 ″ target.

This heat treatment is performed here because the step of manufacturing the head includes a glass bonding step. The FeTaCCrNb alloy film is a microcrystalline precipitation type magnetic material in which the film which was an amorphous film immediately after being formed by annealing is changed to crystalline.

When the crystal structure of the film after the heat treatment was analyzed by an electron diffraction method, two types of α-Fe and TaC were observed from the pattern. From the transmission electron microscope observation results (bright field and dark field, and lattice image observation), the grain size after the heat treatment was 10 nm at the minimum for α-Fe and 25 nm at the maximum, and the average was 16 nm. Further, TaC was 6 nm at the minimum and 10 nm at the maximum, and the average was 8 nm.

Since the additive elements Cr and Nb have the effect of suppressing the growth of crystal grains, they are effective in improving the heat resistance of the magnetic film. In addition, these elements tend to passivate, reducing the probability of reacting with water and oxygen in the environment. Therefore, it is also effective in improving the corrosion resistance. On the other hand, in the comparative example film, the grain size after heat treatment was α-Fe.
Is from 15 nm to 35 nm, and the average is 22n
It was m. Moreover, TaC is from 10 nm to 18 at minimum.
nm and the average was 13 nm.

When the magnetic characteristics of this magnetic film were measured,
Saturation magnetic flux density is 1.6 T, coercive force is 0.10 Oe, relative permeability is 4200 (1 MHz), and magnetostriction constant is 5 × 10 ^−7.
Met. On the other hand, the magnetic characteristics of the magnetic film of the comparative example are that saturation magnetic flux density is 1.4 T, coercive force is 0.90 Oe, relative permeability is 1800 (1 MHz), and magnetostriction constant is 3 × 1.
It was 0 ^-6.

FIG. 1 shows a schematic view of the result of observing the cross section of the magnetic film produced by this example with a transmission electron microscope. From this figure, it can be seen that the magnetic film produced by using this example grows from the surface of the substrate in substantially the same size without increasing the grain size.

The magnetic film produced as described above was immersed in a 0.5N sodium chloride aqueous solution for 500 hours. As a result, no corrosion was found by visual observation. Further, the magnetic characteristics were measured after the immersion for 500 hours. As a result, no difference was observed from the characteristics immediately after the surface treatment. Further, when this magnetic film was allowed to stand in a 95% RH environment at 80 ° C. for 2000 hours or longer, no corrosion was observed and no deterioration of soft magnetic properties such as saturation magnetic flux density and coercive force was observed.

Using this film, a MIG (metal in gap) type head was manufactured. The schematic diagram is shown in FIG.
The head was formed by forming SiOx in a film thickness of 10 nm on the single crystal ferrite substrate 2 having an uneven surface by a sputtering method. The FeTaCCrNb soft magnetic thin film 1 was formed thereon to a thickness of 5 μm by the above method. The sputtering of the magnetic film at that time was performed under the condition that the good film quality was obtained.
Then, the SiOx film was formed again to a film thickness of 200 nm, and then Cr was formed to 100 nm. Since the gap is formed when the magnetic head is made of SiOx and Cr, the thickness of the magnetic head must be precisely controlled.

Next, this block was heated at 590 ° C. for 40 minutes 6
Heat treatment was performed in a magnetic field of kOe. Then, after glass bonding was performed using the low melting point glass 4, it was cut using a wire saw to manufacture a magnetic head having the shape shown in FIG. A VTR device was constructed using this magnetic head. Digital recording was performed using this apparatus, and an S / N of 40 dB was obtained. After the tape was run for 500 hours, the head was dipped in a 0.5N sodium chloride aqueous solution for 500 hours. The head was set again in the apparatus and the recording / reproducing characteristics were measured, but no difference in characteristics was observed before the immersion.

(Example 2) The magnetic thin film used in this example is an example using a FeTaCCrAl alloy film. The film formation was performed using the sputtering method. A ferrite substrate having uneven grooves on its surface was used. An FeTaCCrAl alloy target was used as the sputtering target, and Ar containing 30% Kr was used as the discharge gas. Discharge gas pressure:
Sputtering was performed with a target of 6 mTorr and an input RF power of 400 W / 5 ″. The thickness of the magnetic film thus formed was 5 μm.
It heat-processed at 00 degreeC for 1 hour.

As a comparative example, the same alloy target was used and Ar containing no Kr was used as the discharge gas. The other sputtering conditions are the same as the previous conditions. This film was also heat-treated under the same conditions.

When the crystal structure of the film after the heat treatment was analyzed by an electron diffraction method, two types of α-Fe and TaC were observed from the pattern. From the transmission electron microscope observation results (bright field and dark field, and lattice image observation), the grain size after the heat treatment was 10 nm at the minimum for α-Fe and 25 nm at the maximum, and the average was 16 nm. Further, TaC was 6 nm at the minimum and 10 nm at the maximum, and the average was 8 nm. Here, the additional elements Cr and Al
Has the effect of suppressing the growth of crystal grains, and is effective in improving the heat resistance of the magnetic film. The grain size was the same as in the previous example, despite the different sputtering conditions.

On the other hand, a magnetic film (comparative example) produced on a substrate having irregularities on the surface by using pure Ar containing no Kr as a discharge gas, particularly the sloped portions of the irregularities and other portions. The membrane structure was different. Reflecting this, in the grain size of the film of the comparative example, α-Fe had a minimum of 15 nm to a maximum of 35 nm, and the average was 22 nm. Also, T
The aC was 10 nm at the minimum and 18 nm at the maximum, and the average was 13 nm.

When the magnetic characteristics of the magnetic film produced by using this example were measured, the saturation magnetic flux density was 1.6 T, the coercive force was 0.15 Oe, the relative permeability was 4500 (1 MHz), and the magnetostriction constant was 6. It was × 10 ^-7 . On the other hand, the magnetic characteristics of the magnetic film of the comparative example are as follows: saturation magnetic flux density is 1.3 T, coercive force is 1.0 Oe, relative permeability is 2200 (1 MHz),
And the magnetostriction constant was 3 × 10 ⁻⁶ .

The magnetic film produced as described above was immersed in a 0.5N aqueous sodium chloride solution for 500 hours. As a result, no corrosion was found by visual observation. Further, the magnetic characteristics were measured after the immersion for 500 hours. As a result, no difference was observed from the characteristics immediately after the surface treatment. Further, when this magnetic film was allowed to stand in a 95% RH environment at 80 ° C. for 2000 hours or longer, no corrosion was observed and no deterioration of soft magnetic properties such as saturation magnetic flux density and coercive force was observed.

Using this film, a MIG (metal in gap) type head was produced. Its schematic diagram is similar to that of the first embodiment and is shown in FIG. The head is made of SiOx on the single crystal ferrite substrate 2 having an uneven surface by sputtering with a thickness of 10 n.
It was formed to a film thickness of m. On top of that, FeT
The aCCrAl soft magnetic thin film 1 was formed to a film thickness of 5 μm.
The sputtering of the magnetic film at that time was performed under the condition that the good film quality was obtained. Then, the SiOx film is again set to 200 nm.
Then, Cr was formed to a thickness of 100 nm. Since the gap in the case where the magnetic head is manufactured is composed of SiOx and Cr, the thickness of the magnetic head must be precisely controlled.

Next, this block is placed at 590 ° C. for 40 minutes 6
Heat treatment was performed in a magnetic field of kOe. Then, after glass bonding was performed using the low melting point glass 4, it was cut using a wire saw to manufacture a magnetic head having the shape shown in FIG. A VTR device was constructed using this magnetic head. Digital recording was performed using this apparatus, and an S / N of 39 dB was obtained. After the tape was run for 500 hours, the head was dipped in a 0.5N sodium chloride aqueous solution for 500 hours. The head was set again in the apparatus and the recording / reproducing characteristics were measured, but no difference in characteristics was observed before the immersion.

[0035]

According to the present invention, the crystallographic structure and magnetic properties of the magnetic thin film can be controlled by controlling the atmosphere and conditions under which the magnetic film is produced. As a result, a magnetic film having a uniform film quality can be produced regardless of the type, surface condition and shape of the substrate. This corresponds to good uniformity of magnetic properties. Furthermore, this film has a high corrosion resistance and a highly reliable magnetic film is obtained. By applying this film to a magnetic head and further to a magnetic recording device, a device having high performance and high reliability can be obtained. .

[Brief description of drawings]

FIG. 1 is a schematic view of a surface and a cross section of a magnetic film according to an example of the present invention.

FIG. 2 is a perspective view of a MIG type head and an enlarged view of essential parts.

[Explanation of symbols]

1 ... Soft magnetic thin film, 2 ... Ferrite substrate, 3 ... Gap part, 4 ... Low melting point glass.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigekazu Otomo 1-280, Higashi Koigokubo, Kokubunji, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd.

Claims (18)

[Claims] 1. A process for producing a magnetic thin film having soft magnetic properties, the crystallographic structure of the magnetic thin film is controlled by selecting a film forming atmosphere and / or film forming conditions, and the soft magnetic property of the magnetic film is controlled. And a method for producing a magnetic thin film, characterized in that the corrosion resistance is controlled. 2. In a process for producing a magnetic thin film having soft magnetic properties, a substrate having a non-flat surface is used as a substrate for forming the magnetic film, and a film forming atmosphere and / or film forming conditions are selected on the substrate. A method for producing a magnetic thin film, characterized in that a magnetic film having the same film structure is produced at any position independently of the shape of the surface of the substrate by performing film formation in accordance with. 3. A method of manufacturing a magnetic thin film, wherein a structure in the film thickness direction of a magnetic thin film is controlled by controlling a film forming atmosphere and / or film forming conditions in a process of manufacturing a magnetic thin film having soft magnetic characteristics. 4. The crystallographic structure of the magnetic thin film to be controlled according to claim 1, 2 or 3, has a bulk density of the film, an internal stress,
The structure of the magnetic thin film, which is at least one of the grain sizes. 5. A magnetic thin film having a saturation magnetic flux density of 1.5 T or more and a coercive force of 1 Oe or less as a result of controlling the soft magnetic characteristics according to claim 1 or 2. 6. A material mainly containing Fe and Ta in a concentration range of 5 at% to 20 at% and C in a concentration range of 1 at% to 20 at%.
-Structure of magnetic thin film in which Fe phase and TaC phase are deposited. 7. A material mainly containing Fe in a concentration range of 5 at% to 20 at% and Fe in a concentration range of 1 at% to 20 at%, and α is formed by a microcrystal precipitation reaction after film formation.
-Structure of magnetic thin film in which Fe phase and TaN phase or FeNx phase are deposited. 8. A sputtering method, an ion plating method, an electron beam evaporation method, or an ion beam evaporation method as a film forming method used for forming the thin film according to claim 1, 2, 3, 4, 5, 6 or 7. Method for producing magnetic thin film using the method. 9. When the magnetic thin film according to claim 1, 2, 3, 4, 5, 6, 7 or 8 is manufactured, the film forming conditions to be controlled are the atmospheric pressure during film forming or film forming. A method of manufacturing a magnetic thin film that is energy used. 10. A film forming atmosphere controlled at the time of forming a thin film according to claim 1, 2, 3, 4, 5, 6, 7 or 8.
A method for producing a magnetic thin film, which is an atmospheric gas used during film formation, and more advantageously, the atmospheric gas is a gas whose main component is Ar or N ₂ . 11. A gas atmosphere containing Ar or N ₂ as a main component, which is used for forming the thin film according to claim 10, is added to 0.1 vol.
%, 30 vol% or less other than mother gas, Ar, N ₂ , X
A method for producing a magnetic thin film, wherein a magnetic film is produced by forming a film in a mixed gas atmosphere containing at least one gas selected from e, Rn, Ne and Kr. 12. Claims 1, 2, 3, 4, 5, 6, 7,
8, 9, 10 or 11, a magnetic head using the soft magnetic thin film for manufacturing a magnetic head used for magnetic recording. 13. A magnetic head in which information is recorded on a moving information recording medium by using a magnetic property of the magnetic head according to claim 12 by using magnetic properties, and a magnetic recording device using the magnetic head. 14. Claims 1, 2, 3, 4, 5, 6, 7,
A magnetic head in which a metal-in-gap type magnetic head using the soft magnetic thin film described in 8, 9, 10, 11, 12 or 13 is manufactured. 15. When manufacturing a metal-in-gap type magnetic head using the soft magnetic thin film according to claim 14, a ferrite substrate having irregularities on the surface is used as a substrate, and the substrate is formed on the substrate. 3, 4, 5, 6, 7, 8, 9,
Prior to forming the soft magnetic thin film using the manufacturing method described in 10 or 11, a layer for controlling the adhesiveness between the magnetic thin film and the substrate and / or the crystallographic and magnetic orientation of the thin film is provided. A method for manufacturing a soft magnetic thin film, in which a soft magnetic thin film is produced after 16. When manufacturing a metal-in-gap type magnetic head using the soft magnetic thin film according to claim 15, the adhesion between the magnetic thin film and the substrate and / or the crystallographic and magnetic orientation of the thin film. As a layer provided to control
At least one kind of thin film selected from the group consisting of Cr, Ta, Nb, CoTaZr alloy, CoNbZr alloy, silicon oxide, silicon nitride, W, Mo and Al is formed, and the film thickness is 10
A method of manufacturing a soft magnetic thin film having a thickness of 0 nm or less, and a magnetic head manufactured using the magnetic film. 17. The method according to claim 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15 or 1
In the production of the soft magnetic thin film according to 6, the crystallographic structure and magnetic properties of the magnetic thin film are controlled by controlling the film forming atmosphere and / or the film forming conditions, whereby water and water of the soft magnetic thin film are controlled. / Or a method for producing a soft magnetic thin film whose chemical or electrochemical reactivity with oxygen is controlled. 18. Claims 1, 2, 3, 4, 5, 6, 7,
8, 9 or 10, by controlling the film forming atmosphere and / or film forming conditions to control the crystallographic structure and magnetic properties of the magnetic thin film, the cross section of the soft magnetic thin film and the water on the surface can be controlled. And / or a method of manufacturing a soft magnetic thin film manufactured so as to have the same chemical or electrochemical reactivity with oxygen.