JPH09147320A - Thin film magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain magnetic poles having excellent write characteristics by constituting the magnetic poles on a substrate out of a 1st magnetic layer and a 2nd magnetic layer having a higher acidproof magnetic material than the 1st magnetic layer and forming the 1st magnetic layer covered with the 2nd magnetic layer. SOLUTION: The surface of the substrate 1 is coated with an insulating film 2, on which a lower magnetic film 3 is formed. A magnetic gap film 4 is formed on the lower magnetic film 3, on which organic insulating layers 5 and 6, a conductor coil 7 and an upper magnetic film 8 are laminated, and moreover, the whole body is covered with a protective film 9. An upper electrode 10 and a lower electrode 11 are formed via the magnetic gap film 4 by tip parts of the upper and lower magnetic films 8 and 3 respectively. The upper magnetic film 8 is composed of the 1st magnetic layer 12 formed on the film 4 and the insulating layers 5 and 6 and the 2nd magnetic layer 13 formed to cover the 1st magnetic layer 12. The 1st magnetic layer 12 is formed of a magnetic material having saturation magnetic flux density higher than 1T.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductive type magnetoresistive effect (M) used in a magnetic recording device.
The present invention relates to various types of thin-film magnetic heads such as R) type, perpendicular recording type, and probe type.

[0002]

2. Description of the Related Art In recent years, in order to increase capacity and density in magnetic recording, in addition to improving magnetic characteristics, mechanical characteristics and reliability of the recording medium, a high saturation magnetic flux density capable of sufficiently magnetizing the recording medium. The thin film magnetic head using the magnetic material is widely used. In addition to the inductive head that has been widely used in the past, a thin-film magnetic head has a read-only MR head whose reproduction output is larger than that of the inductive head and does not depend on the relative speed with the recording medium, or a recording medium perpendicular to its film surface. There is a perpendicular recording type vertical thin-film magnetic head that is magnetized in various directions, and various improvements have been made as the magnetic recording apparatus becomes smaller and has a larger capacity and higher performance.

Since the magnetic pole magnetic film of the thin film magnetic head is required to have a high saturation magnetic flux density and a high magnetic permeability, it has a N ratio higher than that of the prior art.
Permalloy alloy films such as iFe are generally used.
Recently, in order to improve the recording / reproducing characteristics, in particular, to enhance the magnetic flux density at the time of writing, CoN in which Co is added to the NiFe film
Magnetic materials having a high magnetic flux saturation density such as an iFe film, a Co-based alloy film, a Fe-based alloy film, and a Fe-based multilayer film have been developed as magnetic pole materials.

[0004]

Generally, in the process of forming a thin film magnetic head on a substrate, an acid solution is used to etch or remove a resist frame or photomask used for forming a desired magnetic film. Is performed. However, since the above-described magnetic material having a high magnetic flux saturation density generally has lower acid resistance than the conventional NiFe film, there is a problem that the above-mentioned acid treatment easily corrodes and the yield decreases. Further, in general, a magnetic film having a high saturation magnetic flux density has a problem that the reproducing sensitivity is lowered because the soft magnetic property is not good.

Therefore, an object of the present invention is to provide a magnetic pole having a high saturation magnetic flux density of 1 stella or more and to have excellent acid resistance that the magnetic pole structure does not corrode by an acid treatment during film formation. (EN) A thin film magnetic head which can be easily manufactured by using, and has excellent recording / reproducing characteristics and is suitable for mass production.

[0006]

The thin film magnetic head of the present invention is intended to achieve the above-mentioned object, and the magnetic pole formed on the substrate is made of a magnetic material having a saturation magnetic flux density higher than 1 stella. It is characterized in that it comprises a magnetic layer and a second magnetic layer made of a magnetic material having a higher acid resistance than the first magnetic layer, and the second magnetic layer is formed so as to cover the first magnetic layer.

With this structure, it is possible to easily form a magnetic pole having a saturation magnetic flux density higher than 1 stella at low cost by using the conventional manufacturing technique as it is.
Moreover, since the first magnetic layer is protected by the second magnetic layer from the acid treatment performed during the film formation process on the substrate, there is no risk of corrosion. Furthermore, since the second magnetic layer is present on both sides of the first magnetic layer, the leakage magnetic flux at both ends of the magnetic gap is small, so that writing to the track end is reduced and excellent off-track characteristics are obtained. . Particularly, when the conventional NiFe film is used for the second magnetic layer, the first magnetic film having poor soft magnetic characteristics is covered with the NiFe film having excellent soft magnetic characteristics, which effectively reduces the reproduction sensitivity. It is convenient because it can be resolved.

Further, when the magnetic pole is formed in a shape in which each corner on the side opposite to the magnetic gap of the second magnetic layer is rounded and curved, the opposite side of the magnetic gap of the magnetic pole, that is, the outer edge, moves the recording medium. With respect to the direction, it has a width in the front-rear direction, which is advantageous because the magnetic flux is dispersed and the undershoot generated in the reproduction output waveform can be flattened. According to the present invention, since the first magnetic layer is covered with the second magnetic layer, the outer edge of the magnetic pole can be easily formed into a curved shape.

In one embodiment, the first magnetic layer may be formed so as to be exposed on the surface facing the recording medium, thereby increasing the saturation magnetic flux density of the magnetic pole, and particularly overwriting during writing. The light characteristics can be enhanced. In another embodiment, the first magnetic layer can be formed so as not to be exposed from the surface facing the recording medium, so that the conventional magnetic head can be used in subsequent head processing steps, environmental tests performed after head assembly, and during use. The same excellent acid resistance or corrosion resistance as that of the NiFe film can be maintained and high reliability can be obtained.

Further, according to the present invention, there is provided a pair of an upper magnetic pole and a lower magnetic pole which face each other across a magnetic gap, and at least one of the magnetic poles is made of a magnetic material having a saturation magnetic flux density higher than 1 stella. A magnetic layer and a second magnetic layer made of a magnetic material having a higher acid resistance than the first magnetic layer, and the second magnetic layer is the first magnetic layer.
There is provided an inductive thin film magnetic head characterized by being formed so as to cover a magnetic layer.

Also in such an induction type thin film magnetic head,
The upper magnetic pole can be formed by the first magnetic layer and the second magnetic layer, and each corner of the second magnetic layer on the side opposite to the magnetic gap can be rounded, whereby an undershoot of the reproduction output can be achieved. Can be reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings using embodiments. 1A, B
Shows a first embodiment of an inductive thin film magnetic head to which the present invention is applied. An insulating film 2 of alumina or the like is deposited on the surface of a substrate 1 made of an Al ₂ O ₃ —TiC ceramic material, and a lower magnetic film 3 of a permalloy alloy such as a NiFe film is formed on the substrate 2 in a predetermined size and shape. ing. A magnetic gap film 4 made of alumina or the like is formed on the lower magnetic film 3, and an organic insulating layer 5 made of novolac resin or the like is formed on the magnetic gap film 4.
6, a conductor coil 7 made of Cu, and an upper magnetic film 8 are laminated, and the whole is covered with a protective film 9 such as alumina. A pair of upper magnetic pole 10 and lower magnetic pole 11 that face each other via the magnetic gap film 4 forming a magnetic gap are formed by the respective tip portions of the upper and lower magnetic films 8 and 3.

The upper magnetic film 8 includes a first magnetic layer 12 formed on the magnetic gap film 4 and the organic insulating layers 5 and 6, and the first magnetic layer 12 as well shown in FIG. 1B. And a second magnetic layer 13 formed so as to cover The first magnetic layer 12 is formed of a magnetic material having a saturation magnetic flux density higher than 1 T, such as the above-mentioned CoNiFe film. On the other hand, the second magnetic layer 13 is formed of a permalloy alloy such as a NiFe film which has been conventionally used, like the lower magnetic film 3. Further, as shown in FIG. 1B, in the surface 14 facing the recording medium, the upper surface of the second magnetic layer 13 forming the outer edge of the upper magnetic pole 10 has rounded corners at both ends.

As described above, the upper magnetic pole 10 is made of a magnetic material having a saturation magnetic flux density higher than 1 T, so that the magnetic flux density is increased as compared with the conventional case where only the NiFe film is used. It is possible to improve the writing characteristics. Further, as shown in FIG. 1B, the NiFe film of the second magnetic layer 13 is present on both sides of the first magnetic layer 12, so otherwise, for example, when the entire top pole is formed of the first magnetic film, Compared to the case where the second magnetic layer is simply laminated on the first magnetism, the leakage magnetic flux at both ends of the magnetic gap is small, and therefore writing to the track end portion is small. Therefore, excellent off-track characteristics are obtained. can get.

Further, since a material having a high saturation magnetic flux density generally does not have a good soft magnetic property, the reproduction sensitivity is lowered when the material is used as a magnetic pole material. According to the present invention, the first magnetic layer 12
Since the second magnetic layer 13 made of a NiFe film having a better soft magnetic characteristic than that is covered with the second magnetic layer 13, excellent reproducing characteristics can be obtained as compared with the case where it is not.

Furthermore, since both side corners of the upper surface of the second magnetic layer 13 are formed to be round and the upper magnetic pole 10 is curved so as to be convex upward, the thickness of the upper magnetic pole changes along the magnetic gap. Become. Therefore, the undershoot waveform generated at the outer edge of the magnetic pole gradually changes in accordance with the change in the thickness of the magnetic pole, so that the undershoot of the reproduction output waveform can be reduced and the reproduction characteristic is improved.

2A to 2D sequentially show steps of forming the upper magnetic pole of the first embodiment described above. 2A, on the substrate 1 on which the lower magnetic pole 11 (lower magnetic film 3), the magnetic gap film 4, the organic insulating layers 5, 6 and the conductor coil 7 are formed,
A base metal film (not shown) is deposited, and the photoresist coated thereon is patterned into a desired size and shape of the first magnetic layer 12 to form a resist frame 15. Next, by electroplating, a material having a high saturation magnetic flux density, such as CoNiFe, is laminated to a thickness required for the lower magnetic pole to form the first magnetic layer 12 as shown in FIG. 2B. In addition to CoNiFe, various magnetic materials having a saturation magnetic flux density higher than 1 T can be used for the first magnetic layer 12.

After removing the resist frame 15 and the unnecessary magnetic film portion 16 by wet etching, a photoresist is applied and patterned into a desired size and shape of the lower magnetic pole to form a resist frame 17 (FIG. 2).
C). Using this, a permalloy alloy (for example, NiFe) is similarly laminated by electroplating to a thickness required for the upper magnetic pole to form the second magnetic film 13 as shown in FIG. 2D. At this time, the first magnetic film 1 is formed on the magnetic gap film 4.
Since there is a step due to 2, the second magnetic film 13 has a shape in which the corners on both sides of the upper surface thereof are rounded and curved as illustrated. Finally, the resist frame 17, the unnecessary magnetic film portion 18, and the underlying metal film below them are removed by ion milling or wet etching in the same manner as in the conventional case, so that the desired upper magnetic pole is obtained as shown in FIG. 2E. 10 is obtained.

As described above, the magnetic pole structure of the thin film magnetic head according to the present invention can be formed relatively easily by utilizing the conventional manufacturing method using the photolithography technique.
Moreover, the first magnetic film 12 is formed even if an etching solution or an organic solvent having strong acidity is used in the subsequent process.
Since it is covered with 3, there is no risk of corrosion. Therefore, the top pole 10 can be formed to have a desired track width and film thickness, and the yield does not decrease.

FIGS. 3A and 3B show a second embodiment of the inductive type thin film magnetic head according to the present invention. In the magnetic pole structure of the first embodiment, the tip of the first magnetic film 12 is exposed on the surface 14 facing the recording medium, whereas in the magnetic pole structure of the second embodiment, the tip of the first magnetic film 12 is The recording medium facing surface 14 covered with the second magnetic film 13 on the magnetic gap film 4.
It is designed so that it is not exposed at all. Further, as shown in FIG. 3B, the second magnetic film 1 on the recording medium facing surface 14 is formed.
3, the corners on both sides of the upper surface are substantially right angles, and the outer edge of the top pole 10 is formed in a straight line parallel to the magnetic gap.

As described above, the first magnetic film 12 is completely covered not only on both sides but also on the tip portion by the second magnetic film 13, so that the head element is cut out from the wafer and the thin film magnetic head is finally used as a slider. In the finishing process, or in an environmental test performed after assembling the thin film magnetic head, the first magnetic film 12 is prevented from being corroded or contaminated by an acid or the like, and the yield and reliability can be further improved.

The thickness of the second magnetic film 13 covering the tip of the first magnetic film 12, that is, the distance b from the recording medium facing surface 14 to the tip of the first magnetic film is a so-called slow height (gap depth) a. The magnetic flux from the first magnetic film 12 is relatively less disturbed by the writing because of the smaller magnetic field. Therefore, a sufficiently high saturation magnetic flux density can be secured as compared with the conventional magnetic pole structure. Usually, the first magnetic film 12 is protected from acids and the like, and a high saturation magnetic flux density is obtained.
The thickness b of 3 is preferably about 0.5 to 1 μm.

The upper magnetic pole of the second embodiment can be formed according to the process shown in FIG. 4 by the manufacturing method using the conventional photolithography technique as in the first embodiment.
First, similarly to the first embodiment, a base metal film (not shown) is formed on the substrate 1 on which the lower magnetic pole 11 (lower magnetic film 3), the magnetic gap film 4, the organic insulating layers 5 and 6 and the conductor coil 7 are formed. And the photoresist applied thereon is patterned to define the size and shape of the first magnetic layer 12, in particular the position of the tip thereof.
Are formed (FIG. 4A). Next, as shown in FIG. 4B, a material having a high saturation magnetic flux density such as CoNiFe is laminated by electroplating to a thickness required for the lower magnetic pole, and the first magnetic layer 12 is formed.
To form

After removing the resist frame 19 and the unnecessary magnetic film portion 20 by wet etching (FIG. 4C),
A resist frame that defines the size and shape of the desired bottom pole is formed, and N is electroplated as shown in FIG. 4D.
The second magnetic film 13 is formed by laminating a permalloy alloy such as an iFe film to a thickness required for the upper magnetic pole. Then, as in the conventional case, the resist frame and the unnecessary magnetic film portion 1 are formed.
8 and the underlying metal film below them by ion milling or wet etching to cover the protective film 9 and cut out at the position indicated by the imaginary line c.
A thin film magnetic head having the desired upper magnetic pole 10 shown in A and B can be obtained.

[0025]

【Example】

(Embodiment 1) In the first embodiment shown in FIG. 1, the first magnetic film 12 of the top pole 10 is made of CoN having a width of 3 μm and a film thickness of 1 μm.
The second magnetic film 13 is formed of an iFe film and has a width of 4 μm.
and a NiFe film having a thickness of 3 μm. When the head characteristics of such a thin film magnetic head were measured, it was confirmed that the write overwrite characteristic was higher than the conventional thin film magnetic head by 10 dB or more, and the undershoot of the reproduction output waveform was reduced by about 70%. . Also,
In the manufacturing process of the thin film magnetic head, the first magnetic film was not corroded by acid or the like, and it was confirmed that the first magnetic film had sufficient corrosion resistance.

(Embodiment 2) In the second embodiment shown in FIG. 3, the first magnetic film 12 of the top pole 10 has a width b of 1 μm and a width of 3 μm and a thickness C of 1 μm.
formed of an oNiFe film, and the second magnetic film 13 has a width of 4 mm.
It was formed by a NiFe film having a thickness of 3 μm and a thickness of 3 μm. When the head characteristics of such a thin film magnetic head were measured, it was confirmed that the write overwrite characteristic was higher than the conventional thin film magnetic head by 7 dB or more. In addition, it was confirmed that the first magnetic film had sufficient corrosion resistance because no corrosion due to acid or the like was observed.

[0027]

According to the thin-film magnetic head of the present invention, since the magnetic pole has a high saturation magnetic flux density of 1 stella or more, the write characteristics are greatly improved. Moreover, since the first magnetic layer is covered with the second magnetic layer, the influence of leakage magnetic flux at both ends of the magnetic gap on writing is small, and excellent off-track characteristics can be obtained. In particular, if the second magnetic film is formed of a NiFe film having excellent soft magnetic characteristics, it is possible to eliminate the decrease in reproduction sensitivity, so that a thin film magnetic head having excellent recording and reproduction characteristics can be obtained. In addition, since the first magnetic layer is protected from the acid treatment by the second magnetic layer that covers the first magnetic layer in the film forming step, it has good corrosion resistance and can be easily manufactured by a conventional manufacturing technique without lowering the yield. Therefore, it is suitable for mass production, and the manufacturing cost can be reduced.

According to the thin film magnetic head of the present invention,
Since both side corners of the upper surface of the second magnetic layer covering the first magnetic layer are formed in a rounded and curved shape, in the case of the magnetic pole in which the first magnetic layer is exposed to the recording medium facing surface, the outer edge of the magnetic pole is formed. Has a convex shape on the opposite side of the magnetic gap, and it is possible to reduce the undershoot of the reproduction output waveform.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of an inductive type thin film magnetic head according to the present invention, and FIG. 1B is an enlarged view of the magnetic pole tip portion as seen from the recording medium side.

2A to 2E are cross-sectional views showing a process of forming a magnetic pole according to the first embodiment, which are shown in FIGS.

FIG. 3A is a longitudinal sectional view showing a second embodiment of the inductive type thin film magnetic head according to the present invention, and FIG. 3B is an enlarged view of the magnetic pole tip portion viewed from the recording medium side.

FIG. 4 is a vertical cross-sectional view of FIGS. 4A to 4D showing a process of forming a magnetic pole according to a second embodiment in the order of steps.

[Explanation of symbols]

 1 substrate 2 insulating film 3 lower magnetic film 4 magnetic gap film 5, 6 organic insulating layer 7 conductor coil 8 upper magnetic film 9 protective film 10 upper magnetic pole 11 lower magnetic pole 12 first magnetic layer 13 second magnetic layer 14 recording medium facing surface 15 resist frame 16 magnetic film portion 17 resist frame 18 magnetic film portion 19 resist frame 20 magnetic film portion

Claims (6)

[Claims] 1. A magnetic pole formed on a substrate comprises a first magnetic layer made of a magnetic material having a saturation magnetic flux density higher than 1 stella (T), and a second magnetic layer made of a magnetic material having a higher acid resistance than the first magnetic layer. And a second magnetic layer formed so as to cover the first magnetic layer. 2. The thin film magnetic head according to claim 1, wherein the magnetic pole is formed in a shape in which each corner of the second magnetic layer opposite to the magnetic gap is rounded and curved. 3. The thin-film magnetic head according to claim 1, wherein the first magnetic layer is exposed on a surface facing a recording medium. 4. A first magnetic layer of a magnetic material having a pair of upper magnetic pole and lower magnetic pole facing each other with a magnetic gap interposed therebetween, wherein at least one of the magnetic poles has a saturation magnetic flux density higher than 1 stella, and A thin-film magnetic head comprising a second magnetic layer made of a magnetic material having a higher acid resistance than the first magnetic layer, the second magnetic layer being formed so as to cover the first magnetic layer. 5. The at least one magnetic pole is the upper magnetic pole, and each corner of the second magnetic layer of the upper magnetic pole on the side opposite to the magnetic gap is formed into a rounded curved shape. The thin film magnetic head according to claim 4. 6. The thin-film magnetic head according to claim 4, wherein the first magnetic layer is exposed on a surface facing a recording medium.