JP3204252B2 - Thin film magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head suitable for high-density magnetic recording, and more particularly to a thin film magnetic head using a material having a high saturation magnetic flux density and having excellent write performance.

[0002]

2. Description of the Related Art In recent years, progress in increasing the density and performance of magnetic recording has been remarkable. In particular, in the field of magnetic disk drives for large computers, a large increase in capacity has been achieved by a significant improvement in recording density. In a magnetic disk device, a thin film magnetic head that has a smaller inductance, a higher high-frequency magnetic permeability, and a smaller track width than a conventional ferrite type head has been partially put to practical use. Conventionally, as seen in JP-A-55-87323, a thin-film magnetic head has been manufactured using a Ni-Fe (permalloy) alloy having a saturation magnetic flux density of 1T. FIG. 4 is a sectional view of a magnetic pole portion of a thin-film magnetic head formed using a Ni—Fe alloy. In FIG. 4, Al ₂ O ₃ —TiC ceramic, Al ₂ O ₃ −
TiO ₂ ceramics, SiC, Zn ferrite, Ni
A sputtered Al ₂ O ₃ film 12 is formed on an insulating substrate 1 made of -Zn ferrite, Mn-Zn ferrite, or the like.
Next, the lower magnetic pole 2 is formed by a Ni-Fe alloy sputtering method. The film thickness was 1.5 μm. Next, a magnetic gap 3 is formed by sputtering Al ₂ O ₃ .

As the insulating layer 5 of the coil conductor 4, a heat-resistant polyimide resin or resist is used. The coil conductor 4 is formed by sputtering using Cu. Next, the upper magnetic pole 10 is formed in the same manner as the lower magnetic pole 2 by a Ni-Fe alloy sputtering method. The film thickness is 2.
It was set to 0 μm. A typical composition of the Ni—Fe alloy is 19 wt% -81 wt% Fe at which the magnetostriction becomes zero. Further, it is made of a protective film 7 of Al ₂ O ₃ of about 20 μm. Lower magnetic pole 2, magnetic gap 3, coil conductor 4,
The upper magnetic pole 10 is formed by ion milling. By the way, in order to improve the recording density, it is necessary to increase the coercive force of the medium. In order to cope with this, it is necessary to increase the thickness of the magnetic pole so that a large magnetic field is emitted from the tip of the head magnetic pole. However, when the thickness of the magnetic pole is increased, there is a problem that the reproduction resolution is reduced. In order to cope with both the problem of increasing the coercive force of the medium and the reduction of the reproduction resolution accompanying the improvement of the recording density, the conventional saturation magnetic flux density of 1
It is said that the Ni-Fe alloy of T is insufficient, and it is necessary to use a high saturation magnetic flux density magnetic material for the magnetic pole magnetic film.

In recent years, an amorphous sputtered film has been developed as a high-performance magnetic film having a high saturation magnetic flux density. Among them, an amorphous alloy in which the vitrifying element is made of Zr or Hf is particularly excellent in corrosion resistance and abrasion resistance, and has excellent characteristics as a magnetic film for a magnetic head. Specifically, MaTb
It can be represented by the composition formula of Ac. Here, M is at least one of Co, Fe, Ni, etc. having a magnetic moment,
A is at least one of Zr and Hf. T is a transition metal other than M and A. In particular, JP-A-58-9882
4, JP-A-60-21504, JP-A-62-28285
0, a CoTaZr-based amorphous alloy such as Co
TaHf-based amorphous alloys and CoTaPd-based amorphous alloys are considered to be promising as magnetic films for thin-film magnetic heads because a saturated magnetic flux density of 1.3 T can be obtained at zero magnetostriction. Japanese Patent Application Laid-Open No. S59-130408 discloses a crystalline alloy film.
As described in U.S. Pat. No. 5,838,898, a multilayer film of an Fe--C alloy and a Ni--Fe alloy and a multilayer film of an FeSiRu alloy and a Ni--Fe alloy have been developed as high-performance magnetic films with high saturation magnetic flux density.

[0005]

However, all of the high saturation magnetic flux density materials described above are thermally metastable materials, and are extremely thermally stable as compared with conventionally used Ni-Fe alloys. There is a problem that it is inferior. For example, a thin film magnetic head having a structure similar to that shown in FIGS. 3 and 4 was formed by using the CoTaZr amorphous alloy film for the upper magnetic pole and the lower magnetic pole. However, due to the thermal history during the thin-film head manufacturing process, the magnetic properties of the CoTaZr amorphous magnetic film of the lower magnetic pole deteriorate, and only a head having a lower reproducing efficiency than the thin-film magnetic head having the structure shown in FIGS. 3 and 4 can be obtained. Was.

An object of the present invention is to solve the above-mentioned problems and to obtain a thin-film magnetic head having excellent recording capability and excellent reproduction efficiency.

[0007]

In order to achieve the above object, according to the present invention, a thermally metastable high saturation magnetic flux density magnetic material having a saturation magnetic flux density of 1.3 T or more is provided on at least a part of an upper magnetic pole. Apply, the lower pole is the conventional saturation magnetic flux density 1T
Therefore, a Ni—Fe alloy (permalloy) having excellent thermal stability was applied.

With this structure, even if a thermally metastable high-saturation magnetic flux density material is used, a magnetic head is not deteriorated by the thermal history of the thin-film head process, and a thin-film head having excellent reproduction efficiency can be obtained. Is now available. In addition, by using a high saturation magnetic flux density material for the upper part, the recording ability was improved as compared with the conventional head using only permalloy for the magnetic pole.

According to the present invention, by employing a structure in which a thermally metastable high saturation magnetic flux density material is used for the upper magnetic pole,
Since the soft magnetic characteristics of the high saturation magnetic flux density material are not deteriorated due to the heat history of the thin film magnetic head manufacturing process, a thin film magnetic head having excellent writing performance and excellent reproduction efficiency can be obtained.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to examples.

Embodiment 1 FIGS. 1 and 3 are a sectional view and a perspective view, respectively, of a thin-film magnetic head according to an embodiment of the present invention. In FIG. 1, Al ₂
O ₃ -TiC ceramic, Al ₂ O ₃ -TiO ₂ ceramics, SiC, Zn ferrite, Ni- Zn ferrite, on an insulating substrate 1 made from Mn-Zn ferrite or the like, to form a sputtering an Al ₂ O ₃ film 12. Next, a Ni-Fe alloy is formed as the lower magnetic pole 2 by a sputtering method. The film thickness was 1.5 μm. Next, the magnetic gap 3 is set to Al ₂
O ₃ is formed by a sputtering method. Insulating layer 5 of coil conductor 4
, A heat-resistant polyimide resin or a resist is used. The coil 4 is formed by sputtering using Cu. Next, the upper magnetic pole 6 has a saturation magnetic flux density of 1.3.
A T Co92Ta5Zr3 amorphous alloy film is formed by a sputtering method.
The film thickness was 2.0 μm. Furthermore, about 20 μm Al ₂
It is made of a protective film 7 of O ₃ . Patterning of the lower magnetic pole 2, the magnetic gap 3, the coil conductor 4, and the upper magnetic pole 6,
It is formed by an ion milling method.

Since the Co92Ta5Zr3 amorphous alloy sputtered film has a large anisotropic magnetic field immediately after sputtering, it is necessary to perform heat treatment in a magnetic field. The heat treatment in a magnetic field was performed after forming the Al ₂ O ₃ protective film. When a heat-resistant polyimide resin is used for the insulating layer 5, heat treatment can be performed in a high-temperature magnetic field. First, a magnetic field of 8 kOe is applied in parallel to the track width direction of the magnetic pole, and the magnetic field treatment is performed at 380 ° C. for 1 hour. After that, a magnetic field of 8 kOe was applied perpendicularly to the track width direction to
Heat treatment in a magnetic field for 1 hour was performed. When a resist is used for the insulating layer 5, the heat treatment temperature in a magnetic field needs to be lower than the heat resistant temperature of the resist. At this time, first, an 8 kOe magnetic field is applied in parallel to the track width direction of the magnetic pole to obtain
After performing the heat treatment in a magnetic field at 1 ° C. for 1 hour, a magnetic field of 8 kOe was applied perpendicularly to the track width direction to perform the heat treatment in a magnetic field at 230 ° C. for 1 hour. For comparison, heads having the same head structure and using a Co92Ta5Zr3 amorphous alloy sputtered film for both the lower magnetic pole 2 and the upper magnetic pole 6 were also manufactured. When manufacturing this head, after forming the lower magnetic pole, heat treatment in a magnetic field was performed to reduce the anisotropic magnetic field. At this time, first, an 8 kOe magnetic field is applied in the easy axis direction of the film to perform heat treatment in a magnetic field at 380 ° C. for 1 hour, and then 8 kOe in the hard axis direction of the film.
A magnetic field was applied to perform a heat treatment in a magnetic field at 330 ° C. for 1 hour. By this heat treatment, the anisotropic magnetic field of the Co92Ta5Zr3 amorphous alloy sputtered film could be reduced from 16 Oe to about 5 Oe, and the magnetic permeability could be improved from 700 to 2500.
However, when flowing through the subsequent process, the anisotropic magnetic field increased, and the magnetic permeability decreased. Specifically, for example, when a heat-resistant polyimide resin is used for the insulating layer 5, about 35
After passing through a heat history of 0 ° C for 1 hour, the anisotropic magnetic field
e, and the magnetic permeability decreases to 700. When a resist is used for the insulating layer 5, about 2
Due to the thermal history of 75 ° C for 5 hours, the anisotropic magnetic field is 10
Oe increased and permeability decreased to 1200. However, the magnetic properties of the permalloy film did not deteriorate.

Using the γ-Fe ₂ O ₃ coating medium having a coercive force of 400 Oe and a film thickness of 0.4 μm, the reproduction output and overwrite characteristics of the thin film head manufactured as described above are obtained at a spacing of 0.25 μm. evaluated. Table 1 shows the recording / reproducing characteristics obtained with each head.

[0014]

[Table 1]

The thin film head according to the present invention can provide a reproduction output comparable to that of a conventional permalloy head, and has an overwrite characteristic of about 10 dB as compared with a permalloy head.
Has also improved. In the head using only the Co ₉₂ Ta ₅ Zr ₃ amorphous magnetic pole, the overwrite characteristics were improved by about 12 dB as compared with the permalloy head, but the reproduction output reached only about 70% of the permalloy head. The same results were obtained for amorphous alloys having a large saturation magnetic flux density, such as a CoTaHf-based amorphous alloy and a CoTaHfPd-based amorphous alloy. Similar results were obtained for thermally metastable crystalline materials such as a multilayer film of an FeSiRu alloy and a permalloy alloy, or a multilayer film of an FeC alloy and a permalloy alloy.

Embodiment 2 FIG. 2 shows a cross section of a thin-film magnetic head according to another embodiment of the present invention. In FIG. 2, a sputtered Al ₂ O _{3 is} formed on an insulating substrate 1 made of Al ₂ O ₃ —TiC ceramic, Al ₂ O ₃ —TiO ₂ ceramic, SiC, Zn ferrite, Ni—Zn ferrite, Mn—Zn ferrite, or the like. Membrane 1
Form 2 Next, Ni—Fe is used as the lower magnetic pole 18.
It is formed by an alloy sputtering method. The film thickness was 1 μm. Further, similarly, a Ni-Fe alloy is formed as the lower magnetic pole 29 by a sputtering method. The film thickness was 1.5 μm. Next, the magnetic gap 3 is formed by sputtering Al ₂ O ₃ . As the insulating layer 5 of the coil conductor 4, a heat-resistant polyimide resin,
Alternatively, a resist is used. The coil 4 is made of Cu
And formed by a sputtering method. Next, the upper magnetic pole 110
Then, a Co ₉₂ Ta ₅ Zr ₃ amorphous alloy film having a saturation magnetic flux density of 1.3 T is formed by a sputtering method. The film thickness was 2.0 μm. The upper magnetic pole 211 is formed of permalloy. The film thickness is 1.0
μm. Finally, it is made of a protective film 7 of Al ₂ O ₃ of about 20 μm. The patterning 10, 11 of the lower magnetic poles 8, 9, the magnetic gap 3, the coil conductor 4, and the upper magnetic pole is formed by an ion milling method. Since the Co ₉₂ Ta ₅ Zr ₃ amorphous alloy sputtered film has a large anisotropic magnetic field immediately after sputtering, it is necessary to perform heat treatment in a magnetic field in Example 1.
The same heat treatment in a magnetic field as in Example 1 was performed. When the same recording / reproduction characteristics were evaluated as in Example 1, the overwrite characteristics were almost the same and the reproduction output was improved by 20% as compared with Example 1. It is considered that the reason why the reproduction output was improved was that the volume of the magnetic pole was increased.

[0017]

As described above, only the upper magnetic pole according to the present invention is made of a high-saturation magnetic flux density material having a saturation metastable magnetic flux density of 1.3 T or more such as an amorphous film or a multilayer film. A thin-film magnetic head using a Ni—Fe (permalloy) alloy film having excellent thermal stability for the lower magnetic pole does not deteriorate the soft magnetic characteristics of the high saturation magnetic flux density material due to the thermal history of the thin-film magnetic head process. A thin-film magnetic head having excellent reproduction characteristics as well as characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a thin-film magnetic head using a high saturation magnetic flux density material and permalloy for a magnetic pole.

FIG. 2 is a cross-sectional view of a thin film magnetic head using a high saturation magnetic flux density material and permalloy for a magnetic pole.

FIG. 3 is a perspective view of a thin-film magnetic head.

FIG. 4 is a sectional view of a magnetic pole portion of a thin-film magnetic head using only permalloy as a polarity.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Lower magnetic pole, 3 ... Magnetic gap, 4 ... Coil, 5 ... Insulating layer, 6 ... Upper magnetic pole, 7 ... Protective film, 8 ... Lower magnetic pole 1, 9 ... Lower magnetic pole 2, 10 ... Upper magnetic pole 1 , 11: Upper magnetic pole 2, 12: Al ₂ O ₃ .

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hidetoshi Moriwaki 1-280 Higashi Koikekubo, Kokubunji-shi, Tokyo Inside Hitachi, Ltd. Central Research Laboratory (72) Inventor Kazuo Shiiki 1-280 Higashi Koikekubo, Kokubunji-shi, Tokyo Hitachi, Ltd. Central Research Laboratory (56) References JP-A-60-35315 (JP, A) JP-A-64-42012 (JP, A) JP-A-58-68211 (JP, A) JP-A-1-102712 (JP, A A) JP-A-60-151814 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 5/31

Claims (2)

(57) [Claims] A magnetic material is sputtered and then patterned to form a lower magnetic pole made of a Ni-Fe alloy, and an insulating material is sputtered on the lower magnetic pole and then patterned to form a gap film. Magnetic material with saturation magnetic flux density of 1.3T or more, Ni-
A method of manufacturing a thin-film magnetic head, comprising forming an upper magnetic pole by sequentially sputtering and patterning an Fe alloy. 2. The thin film magnetic material according to claim 1, wherein said magnetic material having a saturation magnetic flux density of 1.3 T or more is a material containing any one of CoTaZr, CoTaHf, and CoTaHfPd-based amorphous alloy. Head manufacturing method.