JPH056513A - Thin film magnetic head and method of manufacturing the same - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the electromagnetic conversion characteristics of a thin film magnetic head for constituting a hard disk of a high density storage device, and at the same time prevent generation of wiggle or popcon noise. The magnetic layers 8, 9/3, and 4 above and / or below the thin-film magnetic head are made of Fe-Ni-based alloy containing 82.5 to 83.7 wt% Ni, and the substrate bias potential is -25 to -250V. It is formed by a bias sputtering method in a gas in which 0.5 to 10.0% of N ² gas is added to Ar gas.

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 used for a hard disk (hereinafter referred to as HD) which is a high density storage device and a method for manufacturing the same.

[0002]

2. Description of the Related Art A thin film magnetic head used for HD is formed by a thin film technique in order to increase the magnetic recording density of a magnetic disk. Usually, a magnetic gap is formed between a lower magnetic layer and an upper magnetic layer on a ceramic substrate. And a copper film forming a coil of a predetermined number of turns that crosses the magnetic circuit through the upper and lower magnetic layers and both magnetic layers, and between the coils,
It is composed by stacking an insulating layer that electrically insulates the coil from the upper and lower magnetic layers.

FIG. 3 shows a conventional HD in which a transducer element 11 is formed by the thin film magnetic head having the above-mentioned structure.
FIG. 3 is a perspective view showing the outer appearance of a thin-film magnetic head for a magnetic disk. In addition,
12 is a slider surface.

The electromagnetic conversion characteristics of the thin film magnetic head greatly depend on the magnetic characteristics of the magnetic film forming the head core, and the thin film magnetic head is generally used in a high frequency range of several MHz to several tens of MHz. The magnetic characteristics in this frequency region become important. In particular, the magnetic permeability of the head core in the magnetic path direction greatly affects the electromagnetic conversion characteristics of the thin film magnetic head.

Therefore, in the thin film magnetic head, uniaxial magnetic anisotropy is imparted to the magnetic film so that the easy axis of magnetization is in the track width direction. Therefore, the track direction becomes the hard axis of magnetization, and the magnetization reversal at the time of excitation is performed by the magnetization rotation, which is faster than the magnetization reversal performed by the domain wall movement.

Further, as a major problem of the thin film magnetic head, there are problems such as "wiggle" and "popcon noise".

Uighur is a phenomenon in which waveform distortion occurs in a reproduced waveform, and was first reported by Jones of IBM in 1979. This wiggle phenomenon causes a signal reading error in the fixed magnetic disk device.
This is due to the fact that the output at the time of reading is accompanied by a time delay component and fluctuations.

It is considered that the cause of the time delay component is that the magnetization reversal at the time of high frequency driving is not entirely performed by the magnetization rotation, but there is a component caused by the domain wall movement. In order to avoid this, all the magnetization reversal components are performed only by the magnetization rotation, it is necessary to fix the domain wall so as not to easily move by high frequency excitation.

In order to fix the domain wall so as not to move easily by high-frequency excitation, a wedge-shaped cut is formed in the edge of the core of the magnetic layer, or a groove is formed on the surface of the core parallel to the easy axis of magnetization. Attempts have been made to make the core shape like a baseball home base.

However, even if these methods are used, it is difficult to completely fix the movement of the domain wall, and the wedge-shaped notch or the groove on the core surface causes a decrease in the effective magnetic permeability of the magnetic layer. .

When the magnetostriction of the magnetic film is large, the magnetization is changed by the stress applied to the magnetic film itself or the magnetic film, the domain wall becomes unstable, and wiggle occurs. In order to prevent this, attempts have been made to make the magnetostriction of the magnetic film negative or to reduce the absolute value of the magnetostriction. To control the value of magnetostriction, there are a method of controlling the composition of the magnetic film and a method of controlling the crystal structure of the magnetic film.

In order to control the magnetostriction to 1 × 10 ⁶ or less, in the case of permalloy (Fe-Ni), the composition must be controlled to ± 0.2% by weight. Further, the composition in which the magnetostriction falls within 1 × 10 ⁶ or less changes depending on the crystal structure, so it is necessary to control both the composition and the crystal structure. However, even with these methods, it is difficult to completely eliminate wiggle.

Popcon noise is spike-like noise that occurs when data is written and data is immediately read. This may cause a read error in a sector servo type fixed disk device. This is considered to be noise observed when the domain wall excited by the write current is pinned for some reason during the relaxation process and then returns to the relaxation state after a delay.

As a cause of pinning the domain wall, when the magnetic layer has a large magnetostriction, an external stress is applied to the magnetic layer due to expansion of the insulating layer due to a magnetic field generated during writing or heat generation of the coil, and the domain wall is restricted. Can be considered.

As a countermeasure against popcon noise, the method of setting the magnetostriction of the magnetic layer to an insulation value of 5 × 10 to ⁷ or less or 1 × 10 to ⁶ or less of negative magnetostriction, or reducing the specific resistance of the coil is used. Alternatively, a method of suppressing heat generation by reducing the resistance of the coil by increasing the cross-sectional area has been attempted.

However, as described above, in order to control the magnetostriction of the magnetic layer to 1 × 10 to ⁶ or less, permalloy (Fe-
In the case of Ni), the composition must be controlled to ± 0.2% by weight. There is also a technical limit to reducing the specific resistance of the coil and increasing the cross-sectional area.

[0017]

SUMMARY OF THE INVENTION The present invention solves the problems described above in a thin film magnetic head used for HD which is a high-density storage device, has excellent electromagnetic conversion characteristics, and eliminates noise such as wiggle and popcon noise. It is an object of the present invention to provide a thin film magnetic head that has been lost and a method for manufacturing the same.

[0018]

According to the present invention, in a thin film magnetic head, at least 82.5 to 83.7 are provided as magnetic layers.
Fe-Ni alloy containing Ni by weight is used, Hk is between 4 and 8 Oe, internal stress is tensile stress, and stress magnitude is 5 × 10 ⁸ to 1 × 10 ¹⁰ dyn / cm ² The effective anisotropy is controlled using a material that is

[0019]

According to the present invention, a Fe-Ni alloy containing 82.5 to 83.7 wt% Ni is used for at least the magnetic layer, and H
k is between 4 and 8 Oe, the internal stress is tensile stress, and the magnitude of stress is 5 × 10 ⁸ to 1 × 10 ¹⁰ dyn / cm ²
By controlling the effective anisotropy by using the material, a thin film magnetic head used for a hard disk that does not generate noise such as Uighur and Popcon noise can be created.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of a thin film magnetic head for explaining an embodiment of the present invention. Hereinafter, the details of the thin film magnetic head of the present invention and the manufacturing method thereof will be described with reference to this drawing.

In [0021] First Al ₂ O ₃ -TiC (AlTiC) on the material of the ceramic substrate 1 created by such as 10 to a base insulating layer 2 of Al ₂ O ₃ by high-frequency sputtering 2
Then, the lower magnetic layers 3 and 4 were formed thereon by a bias sputtering method.

The sputtering conditions are the target composition Fe1.
7.5 wt% to Ni82.5 wt%, the substrate temperature was 100 ° C., and the sputtering gas at the time of sputtering was Ar gas added with 5% of N ² gas so that the total gas pressure was 4 × 10 ³ Torr. The substrate bias voltage was −100 V, and the film formation rate was 780 Å / min.

The composition of the thus formed film was analyzed by a multi-attribute utility analyzer (EPMAU) and the result was 16.8 wt% Fe to 83.2 wt% Ni.

FIG. 2 is a diagram showing a BH curve of the magnetic thin film manufactured as described above. As a result of measurement, Hc is 0.8
Oe and Hk were 7.5 Oe. When Hk of a general magnetic thin film is 4 Oe or less, it causes the anisotropy to collapse due to stress of the protective film, and when it is 8 Oe or more, the effective magnetic permeability is lowered and the output of the head is lowered. Therefore, H
Suitably k is between 4 and 8 Oe. As a result of measuring the magnetostriction of this film, the Ni composition was 0 to −1 × 10 ⁶ when the Ni composition was between 82.5 wt% and 83.7 wt%.

If the magnetostriction exceeds -1 × 10 to ⁶ , it may cause wiggle or popcon noise. Therefore, the Ni composition should be 82.5 to 83.7% by weight. As a result of measuring the internal stress of this film, the tensile stress was 4 × 10 ⁹ dyn / cm ² .

Further, when the stress is 1 × 10 ¹⁰ dyn / cm ² or more, the adhesion to the substrate is lowered and 5 × 10 ⁸ d which causes peeling.
If it is less than yn / cm ² , the effective anisotropy becomes small, which causes noise.

Returning to FIG. 1, after forming the lower magnetic layers 3 and 4,
An insulating layer 5 made of a resist is formed to electrically insulate between the magnetic layer and the coil and between the coil 6 and the coil 7. At this time, the resist is baked in vacuum at 250 ° C. for 2 hours to be completely cured.

Next, the coil 6 of the first layer is laminated by the required number of turns by electroplating, and a copper thin film formed by sputtering is used as an electrode film for electroplating. As the plating bath, a copper sulfate bath, a copper pyrophosphate bath or the like can be used, but in the present invention, the coil was formed by the copper sulfate bath.

Next, an insulating layer 5 made of a resist is formed for electrical insulation between the coils 6 and 7, and vacuum baking is performed. The second layer coil 7 is formed thereon by the same method as the first layer. Further, an insulating layer 5 made of a resist is formed to electrically insulate the coil 7 from the upper magnetic layers 8 and 9, and vacuum baking is performed.

Next, the upper magnetic layers 8 and 9 are connected to the lower magnetic layers 3 and 3, respectively.
A magnetic circuit was formed in the same manner as in No. 4, and finally a protective layer 10 of Al ₂ O ₃ was formed by 40 to 70 μm by a high frequency bias sputtering method. Then, the surface of the protective layer 10 is flattened and shaped into a slider chip as shown in FIG.

[0031]

As described above, according to the present invention, in the thin film magnetic head used for a hard disk which is a high-density storage device, the electromagnetic conversion characteristics are excellent, and noises such as wiggle and popcon noise are eliminated. In the information field which is developing more and more, a great effect can be obtained by using the thin film magnetic head of the present invention as a memory device.

[Brief description of drawings]

FIG. 1 is a sectional view showing a laminated structure of a thin film magnetic head for explaining an embodiment of the invention.

FIG. 2 is a diagram showing a BH curve of the magnetic film of the present invention.

FIG. 3 is a perspective view showing a slider chip of a thin film magnetic head.

[Explanation of Codes] 1 ... Ceramic substrate, 2 ... Base insulating layer, 3, 4 ... Lower magnetic layer, 5 ... Insulating layer, 6, 7 ... Coil, 8, 9
… Upper magnetic layer, 10… Protective layer, 11… Transducer element, 12… Flying slider surface.

Claims (3)

[Claims] 1. A ceramic film having a magnetic gap on a ceramic substrate, an upper magnetic layer and a lower magnetic layer, a copper film forming a coil of a predetermined winding that intersects a magnetic circuit passing through the upper and lower magnetic layers and both magnetic layers, and a coil. In a thin film magnetic head constituted by laminating insulating films electrically insulating between each other and between a coil and upper and lower magnetic layers,
Alternatively, the lower magnetic layer is made of Fe-Ni alloy containing 82.5 to 83.7 wt% Ni, Hk is in the range of 4 to 8 Oe, internal stress is tensile stress, and the magnitude of stress is 5 × 10 ⁸ to 1 A thin-film magnetic head formed of a material having a density of × 10 ¹⁰ dyn / cm ² . 2. The method of manufacturing a thin film head according to claim 1, wherein the upper and / or lower magnetic layers are formed by a bias sputtering method with a substrate bias potential of −25 to −250V. 3. An upper magnetic layer and / or a lower magnetic layer are formed by a bias sputtering method, and N ² gas in Ar gas is 0.5 to 10.0% as a sputtering gas.
The method of manufacturing a thin film head according to claim 1, wherein the thin film head is added.