JPH0782612B2 - Thin film magnetic head and method of manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thin film magnetic head used in a magnetic disk device, a magnetic tape device or the like and manufactured by using an integrated thin film technology.

(Prior Art) In the field of magnetic recording in recent years, higher recording densities have been increasingly developed, and there is a strong demand for the magnetic recording heads that support magnetic recording together with recording media to meet the aforementioned high recording densities. The thin-film magnetic head manufactured by using the integrated thin-film technology has been put into practical use instead of the ferrite head.

The schematic structure of such a thin film magnetic head is shown in FIG. In FIG. ₂ , a soft magnetic thin film such as a NiFe alloy or a NiFe alloy is formed on a substrate (not shown) made of ceramics such as Al ₂ O ₃ —TiC.
A lower magnetic layer 1 made of a Co-metal type amorphous film is formed, and then a nonmagnetic layer (not shown) made of silicon oxide or the like having a film thickness corresponding to a predetermined gap length (GL) is formed by a sputtering method or the like. It is formed by. After that, the coil 13 made of a conductive material such as Cu or Au, and the organic material layer 11 having the functions of both the insulating layer and the step eliminating layer are formed. Further, the upper magnetic layer 12 is formed by using the same soft magnetic material as the lower magnetic layer 1 so as to sandwich the coil 13 and the organic layer 11, and
A thin film magnetic head is constructed by forming terminals 6 for connecting 13 and the circuit system.

In the thin film magnetic head as described above, the inductance of the coil is smaller than that of the conventional ferrite head, so that the resonance frequency becomes high and it is suitable for high recording density. Further, since the thin film magnetic head is manufactured by using the integrated thin film technology, each part of the thin film magnetic head including the lower magnetic layer 1 can be processed with high accuracy, and the mass productivity is excellent, which is advantageous for cost reduction. It has many advantages. Further, the soft magnetic thin film forming the upper magnetic layer 12 or the lower magnetic layer 1 is usually formed of NiFe alloy, sendust, Co-metal type amorphous film, or the like. In comparison, since the saturation magnetization is large and the magnetic permeability at high frequency is also high, it can be said that the magnetic head is suitable for high recording density in terms of material.

(Problems to be Solved by the Invention) However, the thin-film magnetic head as shown in FIG. 2 has a serious problem in achieving high recording density, particularly high track density, as described below. .

That is, in the conventional thin film magnetic head shown in FIG. 2, the track width is set to the lower magnetic layer 1 and the upper magnetic layer 12.
It is defined by the pattern width TW of the soft magnetic material pattern that forms.
Therefore, the increase in track density is realized by narrowing the pattern width TW of the lower magnetic layer 1 and the upper magnetic layer 12 by ion etching in an Ar gas atmosphere, for example. However, if the pattern width TW is processed to 10 μm or less, the magnetic domain structure of the soft magnetic thin film pattern forming the upper magnetic layer 12 and the lower magnetic layer 1 is disturbed, and the electromagnetic conversion rate of the head is lowered or the reproduced waveform is fluctuated or distorted. There was a major drawback that That is, when the pattern width TW is large, the magnetic domain structure of the soft magnetic thin film pattern 10 to be the upper magnetic layer 12 or the lower magnetic layer 1 is as shown in FIG.
The magnetization direction 8 substantially coincides with the direction of the magnetic anisotropy given to the soft magnetic thin film during film formation (left-right direction in FIG. 3A), and the magnetization reversal is Mainly performed in the magnetization rotation mode, the high frequency characteristics show good electromagnetic conversion characteristics with little extension noise. However, on the other hand, when the track width is narrowed to achieve higher track density (3rd
In the figure (b)), the magnetic domain structure of the soft magnetic thin film pattern 10 is disturbed, and especially at the tip of the pattern, the magnetization direction 8 is substantially parallel to the pattern direction (upper and lower in FIG. 3B) due to the shape effect of the pattern. Direction). Therefore, the reversal of magnetization is mainly in the domain wall motion mode, and the magnetic permeability, particularly in the high frequency region, is drastically reduced, and the electromagnetic conversion efficiency is reduced. Furthermore, since the domain wall 9 moves irregularly due to the magnetization reversal, the reproduced waveform fluctuates and is distorted, which is also a serious problem. Further, since the conventional head shown in FIG. 2 is of an electromagnetic induction type, there is a problem that the reproduction output remarkably decreases as the track width becomes smaller. Further, the photoresist pattern for forming the upper magnetic layer 12 has a height of about 10 μm due to the organic layer 11.
There is also a process problem that it is difficult to form a PR pattern, especially a pattern having a width of 10 μm or less, during exposure because the step is formed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a new thin film magnetic head having high electromagnetic conversion efficiency and high track density by eliminating the drawbacks of the conventional thin film magnetic head described above.

(Means for Solving the Problems) According to the present invention, a pair of yokes having a film thickness equal to a predetermined track width and formed on the same plane and formed of a soft magnetic thin film pattern, and each of the yokes. A pair of magnetoresistive elements arranged at the ends without impairing magnetic continuity,
A return path formed of a soft magnetic thin film pattern which is arranged at the end of the magnetoresistive effect element on the side opposite to the yoke without impairing magnetic continuity and magnetically couples the magnetoresistive effect elements to each other. A thin film magnetic head characterized in that the magnetic anisotropy of the yoke and the magnetic anisotropy of the return path are different, and a film thickness equal to a predetermined track width and on the same plane A pair of yokes made of a soft magnetic thin film pattern, and a return path made of a soft magnetic thin film pattern arranged at each end of the yoke without impairing magnetic continuity and magnetically coupling the yokes to each other. A thin film magnetic head in which a coil is formed in either or both of the yoke and the return path, the direction of magnetic anisotropy of the yoke and A thin film magnetic head characterized in that the return path has different magnetic anisotropy directions, and the direction of magnetic anisotropy of the yoke and the direction of magnetic anisotropy of the litter path are different from each other. A method of manufacturing a thin film magnetic head controlled in the direction is obtained.

(Operation) With the magnetic thin film head according to the present invention, it is possible to provide a thin film magnetic head that solves the conventional problems by adopting the above-mentioned configuration. That is, in the thin film magnetic head according to the present invention, the track width is defined by the film thickness of the soft magnetic thin film which is a pair of yokes formed on the same plane. That is,
Higher track density is realized by reducing the film thickness of the soft magnetic thin film, and it is theoretically unnecessary to narrow the thin film pattern forming the upper or lower magnetic layer by etching. Therefore, it is possible to avoid the deterioration of the electromagnetic conversion efficiency and the fluctuation / distortion of the reproduced waveform due to the disturbance of the magnetic domain structure of the thin film pattern forming the upper or lower magnetic layer.

Further, structurally, it is not necessary to form the upper magnetic layer, so that the above-mentioned process problems can be solved.

Further, if the direction of the magnetic anisotropy of the yoke and the direction of the magnetic anisotropy of the return path are different from each other so as to be substantially perpendicular to the signal magnetic flux flowing from the magnetic recording medium, the yoke and the return path may be made different from each other. The magnetization reversal of the path is mainly performed by the magnetization rotation mode. Therefore, it is possible to obtain a thin film head which is excellent in high frequency characteristics and operates with less noise.

As a method of giving magnetic anisotropy to the yoke and the return path, there are a method of forming a film in a magnetic field and a method of annealing in a magnetic field using a cobalt-based amorphous metal alloy. When annealing in a magnetic field, it is necessary to consider that the annealing performed for one of the yoke and the return path does not affect the magnetic anisotropy of the other. It is known that the other annealing temperature should be kept low.

(Embodiment) FIG. 1A shows a first embodiment of the thin film magnetic head according to the present invention.

In FIG. 1 (a), a silicon oxide film of about 10 μm is first formed on an Al ₂ O ₃ —TiC substrate (not shown) by a sputtering method, and then a yoke 2 of Co ₉₀ Zr ₁₀ (weight) is formed. A (ratio) film was formed on the silicon oxide film by a sputtering method. that time,
The CoZr film was formed in a magnetic field in one direction so that the magnetic anisotropy was substantially perpendicular to the x direction in the figure, that is, the direction of the signal magnetic flux flowing from the magnetic recording medium. The track width of the thin film magnetic head of this embodiment is 2 μm because it corresponds to the film thickness of the CoZr film.

Then, the CoZr film is etched by ion milling,
A pair of yokes 2 was formed. Here, the pair of yokes 2 is formed so as to have a gap equal to a predetermined gap length on the medium facing surface side. In this embodiment, this gap is 0.5 μm.

After that, a silicon oxide film was formed on the entire surface of the substrate by a sputtering method to fill the gap and the space between the yoke 2 and the return path 3. Then, the silicon oxide film was flattened by etching back in an Ar gas atmosphere.

After this flattening step, the MR element 4 made of a Ni ₈₁ Fe ₁₉ alloy was formed on each end of the yoke 2 opposite to the medium facing surface.
The film thickness of the MR element was 300 Å, and a vapor deposition device was used for film formation. A Co ₇₀ Pt ₃₀ (atomic ratio) film was similarly formed as a hard magnetic film for applying a bias to the MR element 4. The film thickness is 450 angstrom. Although this CoPt film is formed by stacking on the MR element, it is not shown in order to avoid complexity of the drawing. With this CoPt film
The MR element 4 was biased so that its magnetization direction had a predetermined angle (45 ° in this embodiment) in the same direction as the sense current flowing through the MR element 4.

After that, the terminal 6 made of a conductive thin film pattern for connecting the MR element and the circuit system was formed. The conductor used is Au and its film thickness is 3000 angstroms. here,
An intermediate terminal 5 made of a gold thin film was connected to the conductive thin film pattern for electrically connecting the MR elements to each other.

Further, after forming a silicon oxide film as an insulating film at 3000 angstrom, as a return path 3, a Co ₉₀ Zr film having a film thickness of 2 μm is formed.
_{A 10} (weight ratio) film was formed by the sputtering method. At that time, CoZr
The film was formed in a magnetic field in one direction such that the magnetic anisotropy of the film was perpendicular to the y direction of the figure, that is, the passing direction of the signal magnetic flux flowing from the magnetic recording medium. The transducer of the thin film magnetic head was manufactured as described above.

In the thin film magnetic head according to the first embodiment of the present invention, the track density can be easily increased in terms of process by reducing the thickness of the yoke. In addition, various problems that occur when the track density is increased in the conventional thin film magnetic head, that is, the deterioration of the electromagnetic conversion efficiency and the fluctuation / distortion of the reproduced waveform due to the disorder of the magnetic domain structure are not observed at all.

FIG. 1 (b) shows a second embodiment of the thin film magnetic head according to the present invention. In FIG. 1 (b), a silicon oxide film of about 10 μm is first sputtered on an Al ₂ O ₃ —TiC substrate (not shown).
After forming a film, a lower coil (not shown) made of a Cu-plated film having a film thickness of 1 μm was formed by using a plating method.

Then, an insulating layer of silicon oxide is formed to a thickness of 2000 angstrom by a sputtering method, and first, as a return path 3, Co
_{A 90} Zr ₁₀ film was formed by sputtering to a thickness of 2 μm. After that, the magnetic anisotropy direction of the CoZr film is perpendicular to the passing direction of the signal magnetic flux in the Y direction magnetic field at a temperature of 300.
Annealed in degrees. Next, the upper coil 7 having a film thickness of 1 μm is formed through the insulating layer so as not to impair the electrical continuity with the lower coil.
Was formed, and the terminal 6 for the coil was also connected together. Here, the method of forming the upper coil was exactly the same as that of the lower coil.

Further, as the yoke 2, a Co ₉₀ Zr ₁₀ film having a thickness of 2 μm was formed by a sputtering method. After that, the CoZr film was annealed at a temperature of 250 degrees in a magnetic field in the x direction so that the direction of magnetic anisotropy was substantially perpendicular to the direction of the signal magnetic flux flowing from the magnetic recording medium. We have made a prototype thin film magnetic head transducer.

Even in the thin film magnetic head of the second embodiment according to the present invention,
Although it was a narrow track, recording and reproduction could be performed stably at high frequency, and no noise due to domain wall motion was observed.

In addition, as another embodiment, a thin film magnetic head in which the coil is formed on one yoke instead of the return path and a thin film magnetic head formed on both yokes were also manufactured. It is needless to say that in the latter case, the winding directions of the coils should be taken into consideration so that the magnetic fluxes generated by the coils formed in the respective yokes do not cancel each other out.

(Effects of the Invention) As described above, in the thin-film magnetic head according to the present invention, the track width is defined by the film thickness of the pair of yokes formed on the same plane. It's easy. Further, it is possible to avoid the problems of deterioration of the electromagnetic conversion efficiency and fluctuation / distortion of the reproduced waveform due to the disorder of the magnetic domain structure, which occurs when the track density is increased in the conventional thin film magnetic head. Furthermore, by using an MR element having high reproduction efficiency, extremely high reproduction output can be obtained. Moreover,
Since this MR element is in contact with the recording medium via the yoke, there is also an advantage that noise generation of the MR element due to contact / sliding with the medium is suppressed. Also, by winding a coil around the return path or the yoke, a recording head can be easily realized.

As described above, according to the present invention, a thin film magnetic head having a high reproduction output and a high track density can be easily realized, and it can be said that the present invention has a high industrial value.

[Brief description of drawings]

1 (a) and 1 (b) are perspective views showing an example of a schematic structure of a thin film magnetic head according to the present invention, FIG. 2 is a perspective view showing a conventional example, and FIGS. 3 (a) and 3 (b) are conventional examples. FIG. 6 is a plan view for explaining the problem of FIG. In the figure, 1 ... Lower magnetic layer, 2 ... Yoke, 3 ... Return path, 4 ... MR element, 5 ... Intermediate terminal, 6 ... Terminal, 7 ...
... upper coil, 8 ... magnetization direction, 9 ... domain wall, 10 ... soft magnetic thin film pattern, 11 ... organic material layer, 12 ... upper magnetic layer, 13 ... coil.

Claims (6)

[Claims] 1. A pair of yokes having a film thickness equal to a predetermined track width and formed of a soft magnetic thin film pattern formed on the same plane, and magnetic continuity is not impaired at each end of the yokes. A pair of magnetoresistive effect elements arranged and a soft magnetic element arranged at the end of the magnetoresistive effect element opposite to the yoke without impairing magnetic continuity and magnetically coupling the magnetoresistive effect elements to each other. A thin film magnetic head comprising a return path formed of a thin film pattern, wherein the direction of magnetic anisotropy of the yoke and the direction of magnetic anisotropy of the return path are different. 2. A pair of yokes having a film thickness equal to a predetermined track width and formed of a soft magnetic thin film pattern formed on the same plane, and magnetic continuity is not impaired at each end of the yokes. And a return path formed of a soft magnetic thin film pattern for magnetically coupling the yokes to each other.
A thin-film magnetic head in which a coil is formed on either or both of the yoke and the return path, the direction of magnetic anisotropy of the yoke and the return path.
A thin film magnetic head characterized in that the directions of magnetic anisotropy of paths are different. 3. A pair of yokes each having a film thickness equal to a predetermined track width and formed of a soft magnetic thin film pattern formed on the same plane, and magnetic continuity is not impaired at each end of the yokes. A pair of magnetoresistive effect elements arranged and a soft magnetic element arranged at the end of the magnetoresistive effect element opposite to the yoke without impairing magnetic continuity and magnetically coupling the magnetoresistive effect elements to each other. A method of manufacturing a thin film magnetic head comprising a return path formed of a thin film pattern, wherein the yoke and the soft magnetic thin film pattern used as the return path are formed in magnetic fields in different directions, respectively. And a method of manufacturing a thin film magnetic head, wherein magnetic anisotropy in different directions is applied to the return path. 4. A pair of yokes having a film thickness equal to a predetermined track width and formed of a soft magnetic thin film pattern formed on the same plane, and magnetic continuity is not impaired at each end of the yokes. And a return path formed of a soft magnetic thin film pattern for magnetically coupling the yokes to each other.
A method of manufacturing a thin film magnetic head in which a coil is formed on either or both of the yoke and the return path, wherein soft magnetic thin film patterns used as the yoke and the return path are magnetic fields in different directions. A method of manufacturing a thin film magnetic head, characterized in that magnetic anisotropy in different directions is imparted to the yoke and the return path by forming a film inside. 5. A soft magnetic thin film pattern of cobalt-based amorphous metal is used as a yoke and a return path, and when the soft magnetic thin film pattern is formed and annealed in a magnetic field, the soft magnetic thin film previously formed. The annealing temperature applied to the pattern is higher than the annealing temperature applied to the soft magnetic thin film pattern formed later, and the magnetic field application directions to the respective soft magnetic thin film patterns are different. 4. A method of manufacturing a thin film magnetic head as set forth in claim 3, wherein: 6. A soft magnetic thin film formed by using a cobalt-based amorphous metal soft magnetic thin film pattern as a yoke and a return path, and performing annealing in a magnetic field after forming each soft magnetic thin film pattern. The annealing temperature applied to the pattern is higher than the annealing temperature applied to the soft magnetic thin film pattern formed later, and the magnetic field application directions to the respective soft magnetic thin film patterns are different. 5. A method of manufacturing a thin film magnetic head as set forth in claim 4 above.