JP2003331406A - Recording and reproducing separation type magnetic head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable magnetic head capable of preventing the abrasion of the magnetic head caused by contact by avoiding contact between the head and a recording medium with respect to the reduced floating amount of the magnetic head which accompanies an increase in the capacity of a magnetic disk drive. <P>SOLUTION: Contact between the head and the recording medium is prevented by forming the two layers of protective films, and forming a step retreated to a contact area with the recording medium by head deformation, and the abrasion of the magnetic head is prevented. Thus, the reliability of the magnetic head is improved. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing separated type magnetic head used in a magnetic disk device.

[0002]

2. Description of the Related Art With the demand for larger capacity and smaller size of magnetic disk devices, the recording density thereof is rapidly increasing year by year. In order to meet these requirements, for example, in the present magnetic disk device, a recording / reproducing separated type magnetic head is used, and the reproducing head is a magnetoresistive head GMR.
A (Giant Magnetoresistive) head is used. Further, the track width in the same device is about 0.4 μm, and the gap between the magnetic head and the recording medium (hereinafter, abbreviated as flying height) has been narrowed to about 15 nm.

FIG. 3 schematically shows a cross section of a recording / reproducing separated type magnetic head which employs a GMR head. FIG. 4 is a perspective view of the recording / reproducing separated type magnetic head. The recording / reproducing separated type magnetic head has a structure in which a recording induction type magnetic head, that is, an induction type thin film recording head is laminated on a reproduction-only GMR head. The reproducing GMR head, which is a magnetoresistive reproducing head, is composed of a lower shield film 2, an upper shield film 3, a GMR film 7 for detecting a signal, an electrode film 8 for supplying a current to the GMR film 7, and the like. On the other hand, the inductive thin film recording head has a lower magnetic pole film 3, a recording gap film 9 and an upper magnetic pole film 1 which also serve as an upper shield film of the reproducing head.
2, the coil 10, the insulating layer 11 and the like.

As described above, the gap between the head and the recording medium becomes narrower as the recording density becomes higher. To achieve high-density recording, it is essential to reduce the flying height, that is, to reduce the flying height. However, head deformation is becoming a major problem as the flying height decreases. That is, due to the deformation of the head, the distance between the head and the recording medium is locally narrowed, so that the head and the recording medium collide with each other, and in the worst case, the recording medium is damaged and the recorded data disappears and slides. For a discussion on this issue, see, for example, IEEE.Trans.Magn., V
ol.38,2002, page1 (IAE Transaction on Magnetics Volume 38, 2002
There is a report posted on page 1) for the year. That is, the head is deformed by heating. For example, as shown in FIG. 5, the portion immediately above the top pole film 12 is most deformed. As a result, this area is likely to come into contact with the recording medium and, in the worst case, is worn (wear area 20).

In connection with this problem, Japanese Patent Laid-Open No. 04-366408 discloses a technique of forming a recess in an inorganic insulating protective film of a magnetic induction type recording head, that is, a thin film magnetic head. However, this publication does not disclose the technology of the recording / reproducing separated type magnetic head which is the subject of the present invention. Further, as to the recording / reproducing separated type magnetic head, Japanese Patent Application Laid-Open No. 10-289546 discloses a technique of providing irregularities on a single-layer protective film. However, the countermeasure using a single-layer film has a problem that there is a limitation in the step of forming the concave-convex portion, and there is no disclosure about the countermeasure utilizing the characteristics of the protective film composed of a laminated film of a plurality of layers.

The head deformation will be further described below in relation to the problems of the present invention. The cause of the deformation of the head is the difference in the coefficient of thermal expansion due to the heating of the head. The heating of the head is caused by (1) the environmental temperature in which the head is placed, and (2) the heat generated by the head itself.

(1) The environmental temperature is dominated by the temperature inside the magnetic disk device, and many magnetic disk devices guarantee about 60 ° C. (2) The heat generation of the head itself is due to the coil heat generation at the time of writing, the heat generation due to the eddy current heat generation in the high frequency region and the resistance increase due to the iron loss skin effect. To reduce the deformation, the head temperature may be lowered. Of these, (1) the environmental temperature is a customer specification and the manufacturing side must have a structure that satisfies the requirements. On the other hand, in order to reduce heat generation of the head itself, for example, reduction of coil resistance, narrowing of magnetic pole shape, application of high resistance magnetic pole material, etc. are effective. It is also effective to reduce the volume ratio of materials having a large difference in thermal expansion coefficient. Specifically, it is preferable to make the metal film having a large thermal expansion, for example, the upper and lower shield films small. Further, it is also effective to increase heat dissipation. For this, a heat sink may be provided near the heat source. However, these items are effective means for suppressing the deformation of the head, but it is impossible to completely eliminate the deformation because of the difference in the coefficient of thermal expansion, and the measures against the deformation of the head due to heat generation are improved. Is important.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to avoid contact between the head and the recording medium due to head deformation due to heat generation, which is a problem with the low flying height, which is essential for high density recording, and to improve reliability. It is to provide a high head.

[0009]

In order to solve the above problems, the present invention comprises an upper shield film, a lower shield film, a magnetoresistive effect film, and an electrode film electrically connected to the magnetoresistive effect film. An inductive thin film recording head including a magnetoresistive effect reproducing head, a lower magnetic pole film, a recording gap film, an upper magnetic pole film and a coil formed adjacent to the magnetoresistive effect reproducing head, and the inductive thin film recording head. In a recording / reproducing separated type magnetic head composed of a protective film formed on the head, the protective film is a laminated film composed of an upper protective film and a lower protective film having chemical or physical processability differences. In addition, the upper protective film forms a recessed step on the air bearing surface facing the recording medium with respect to the lower protective film.

Further, Al ₂ O ₃ the upper protective layer is formed by a film from and so as to form a lower protective layer with a film made of a composite composed mainly of Al ₂ O _3.

Further, the lower protective film is formed by a film made of at least one of Al ₂ O ₃ SiO ₂ , Al ₂ O ₃ Zr ₂ O ₃ and Al ₂ O ₃ Y ₂ O ₃ .

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the outline of an embodiment of the present invention will be described with reference to FIGS. First, the thermal deformation of the head, which is a problem in the present invention, will be described with reference to FIG. In the recording / reproducing separated type magnetic head having the conventional structure, due to the influence of heat generated by the coil, the head corner is deformed so as to project forward from the substrate 1 as a base point. As a result, in the recording / reproducing separated type magnetic head having the conventional structure, the wear area 20 shown in FIG. 5 is worn due to contact with the recording medium. The amount of wear is the width w,
It is defined by height h and depth d. In the sample evaluation with the flying height almost zero, the recording frequency was 300MHz and the write current was 50m.
A, environmental temperature is 45 ° C, wear depth d is 20 nm, w
Was 40 μm and h was 22 μm.

On the other hand, in the embodiment of the present invention, the protective film formed in the two-layer structure is processed as shown in FIG. 1 to form the recessed step on the air bearing surface facing the medium with respect to the upper protective film 13b. Avoid contact with the head, prevent wear of the head,
It is possible to provide a highly reliable head.
Here, fine processing accuracy is required for forming the step in the protective film, and the laminated protective film configuration of the present invention, which is composed of a plurality of layers having different processability, is effective.

FIG. 1 is a diagram schematically showing the cross-sectional structure of the head before heating according to the present invention. Here, a part of the upper protective film 13b of the laminated protective film that protects the head element is processed to form a concave step (formation of the preceding processed portion 14, that is, a step that is partially receded on the air bearing surface facing the medium). As is apparent from the deformation caused by heating shown in FIG. 2, by optimizing the depth d of the recess according to the head use condition, the protrusion amount of the head corner can be suppressed and the contact with the recording medium can be prevented.

Several methods can be used to form the concave step (formation of the receding step step). (1) 1
One method is to remove a part of the upper protective film 13b by a physical processing method such as an ion milling method in the head processing step. In this case, it is necessary to protect the upper magnetic pole film 12 and the GMR film 7 exposed on the air bearing surface with a resist or the like. (2) Another method is processing by a wet etching method. Also in this case, damage to the upper magnetic pole film 12 and the GMR film 7 may be suppressed by selecting an appropriate etchant, but since the entire protective film is processed, the upper magnetic pole film 12 and the GMR film 7 are In this case also, it is necessary to protect the upper magnetic pole portion 12 and the GMR film 7 exposed on the air bearing surface with a resist or the like because the convex shape is not preferable. (3) Further, as another method, there is a method of utilizing the difference in processability of the laminated protective film, which is the most effective method of the present invention. Here, since the wet etching method is used, the processing speed, that is, the etching speed is different.
Two-layer protective film, that is, an upper protective film 13b having high processability
A protective film composed of a two-layer laminated film of the lower protective film 13a having low workability was used. Immersing in an optimized etchant by improving the workability of the upper protective film 13b laminated on the lower protective film 13a formed on the side closer to the upper magnetic pole film 12 compared to the processability of the lower protective film 13a. Then, the upper protective film 13b is largely processed, and the head having the desired shape shown in FIG. 1 and having high reliability can be manufactured.

This method also has the following merits. First, in the above methods (1) and (2), an error in the step size is likely to occur due to the deviation of the resist to be protected,
In the worst case, the upper magnetic pole film 12 may fall into the step processing range. On the other hand, in the method (3), the size of the step can be easily controlled by controlling the thickness of the lower protective film 13b formed on the side closer to the upper magnetic pole film 12, so that an error in forming the step is extremely reduced. It can be made smaller.

Further, the electric resistance of the protective film formed on the upper magnetic pole film 12 is preferably as high as possible. This is because eddy current heat generation in the high frequency region of the upper magnetic pole film 12 is suppressed to be lower as the electric resistance of the adjacent insulating film is higher. In the method (3), for example, by stacking Al ₂ O ₃ SiO ₂ having a higher electric resistance than Al ₂ O ₃ as the material of the protective film as the lower protective film 13a, the above effect can be obtained.

Embodiments of the present invention will be described in more detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a view showing a cross section of the recording / reproducing separated type magnetic head of the present invention as described above. The details of the structure and manufacturing method of the recording / reproducing separated type magnetic head of the present invention will be further described with reference to this drawing. The lower shield film 2 is formed on the substrate 1 on which the base alumina film is laminated. The substrate 1 is Al ₂ O ₃ .TiC (alumina titanium carbide). The lower shield film 2 is a NiFe alloy film formed by a plating method. The film thickness is 2 μm. (2) The lower gap film 4 is formed. The material is alumina and the film thickness is 0.05 μm. The film was formed by the sputtering method. Then, it was processed into a desired shape by a photolithography method and an ion milling method. (3) The GMR film 7 was formed and processed into a desired shape by the photolithography method and the ion milling method. The GMR film 7 is a spin valve film having CoFe as a free layer. (4) The magnetic domain control film 6 and the electrode film 8 are formed. The patterning was performed by the lift-off method. The magnetic domain control film 6 is a CoPt film. The electrode film 8 is a stack of Ta and its alloy thin film. (5) The upper gap film 5 is formed. The material is alumina and the film thickness is 0.05 μm. The film was formed by the sputtering method. Then, it was processed into a desired shape by a photolithography method and an ion milling method. (6) Finally, the upper shield film 3 is formed. This upper shield film 3, which also serves as the lower magnetic pole of the inductive thin film magnetic head for recording, is formed of a NiFe alloy film by a plating method. The film thickness is 2μ
m. As described above, the reproducing GMR head element was formed. Next, the inductive thin film magnetic head for recording is laminated. (7) The recording gap film 9 is formed. The material is alumina and the film thickness is 0.2 μm. (8) The coil 10 is formed. The coil 10 was formed by plating with 9 turns. The material is Cu. (9) A photoresist is applied and heat treatment is performed to form the insulating layer 11. The film thickness is 10 μm. (10) The upper magnetic pole film 12 is formed. Material is NiFeC
O, it was formed by a plating method. (11) The lower terminal 15 is formed by plating. Material is C
u. (12) First, as the lower protective film 13b, Al ₂ O ₃ · SiO _{2 is used.}
Is formed to a thickness of 3 μm, and then a normal Al ₂ O ₃ film is continuously laminated in a thickness of 57 μm as the upper protective film 13b. Al ₂ O ₃ · S
iO ₂ is chemically stable and less likely to be etched than Al ₂ O ₃ alone. (13) Lower terminal 15 after polishing the upper protective film with lap
Is exposed, and the upper terminal 16 is formed thereon by a plating method. The material is Au and the film thickness is 6 μm. Thus, the recording head element and the reproducing head element were formed. With respect to this element, (14) the step according to the present invention is formed in the next processing step. At this stage, the process of forming the GMR film 7 into a predetermined shape has already been completed. (15) In step processing step, the etching solution 19 to the etching rate ratio of the Al ₂ O ₃ forming the upper protective layer 13a against Al ₂ O ₃ · SiO ₂ forming the lower protective layer 13b becomes 50 or more The element was dipped for a predetermined time to form a step with a receding amount of 20 nm on the air bearing surface. (16) Thereafter, a C, Si laminated film (not shown) having a thickness of 5 nm is formed on the entire air bearing surface to form an air bearing surface protective film. Subsequently, rails for floating were formed by photolithography and ion milling. (17) The head slider of the recording / reproducing separated type magnetic head is completed by performing the above steps on a bar block on which a plurality of head elements are mounted and then cutting the chip into chips.

In the present embodiment, since the laminated protective film of the present invention having different workability was formed on the upper magnetic pole 12 and the step processing was performed on it, the process is omitted because there is no coating process with the laminated resist. There is an advantage that it can be reduced, and further, since the ion milling method is not used, damage to the head is small.

As a result of measuring the amount of wear of the head slider of this recording / reproducing separated type magnetic head, the flying height was 8 nm and the frequency was 4 nm.
No wear was observed even under the conditions of 00 MHz, Iw 40 mA, and environmental temperature of 60 degrees. The wear depth of the slider before the countermeasure was 15 nm or more under the same condition.

(Example 2) Al ₂ O ₃ .SiO in Example 1
_{Even when} Al ₂ O ₃ .Zr ₂ O ₃ O or Al ₂ O ₃ .Y2O3 was used instead of ₂ , the same abrasion resistance effect as in (Example 1) was obtained.

[0023]

With the aim of avoiding contact with the recording medium due to head deformation due to head heat generation, a film having different workability is laminated on the upper magnetic pole of the head to form a protective film. Was used to form a step. By forming this step, it is possible to avoid contact of the recording / reproducing separated type magnetic head with the recording medium in low flying and to prevent head wear.

[Brief description of drawings]

FIG. 1 is a sectional view of a recording / reproducing separated type magnetic head according to the present invention.

FIG. 2 is a cross-sectional view showing the deformation of the head when the head is heated according to the present invention in comparison with the case of a conventional structure head.

FIG. 3 is a sectional view of a conventional recording / reproducing separated type head.

FIG. 4 is a perspective view of a conventional recording / reproducing separated type head.

FIG. 5 is a schematic view showing head wear due to conventional head deformation.

[Explanation of reference numerals] 1 ... Substrate, 2 ... Lower shield film, 3 ... Upper shield film that also serves as lower magnetic pole, 4 ... Lower jacket film, 5 ... Upper jacket film,
6 ... Domain control film, 7 ... GMR film, 8 ... Electrode film, 9 ... Recording jacket film, 10 ... Coil, 11 ... Insulating layer, 12 ... Upper magnetic pole film, 13 ... Protective film, 13a ... Lower protective film, 13b ... Upper protective film, 14 ...: Preliminarily processed portion for forming air bearing surface facing recording medium, 15 ... Lower terminal, 16 ... Upper terminal, 17 ... Deformation position in conventional structure, 18 ... Bar block, 19 ... Etching solution, 20 ... Wear area.

Continued front page    (72) Inventor Nao Yonekawa             2880 Kozu, Odawara City, Kanagawa Stock Association             Company Hitachi Ltd. Storage Division (72) Inventor Saiki Nobuyuki             2880 Kozu, Odawara City, Kanagawa Stock Association             Company Hitachi Ltd. Storage Division (72) Inventor Mitsuo Suda             2880 Kozu, Odawara City, Kanagawa Stock Association             Company Hitachi Ltd. Storage Division (72) Inventor Yuu Yuto             2880 Kozu, Odawara City, Kanagawa Stock Association             Company Hitachi Ltd. Storage Division F-term (reference) 5D033 BA61 BB43 CA03 CA07                 5D034 BA17 BB12 CA01 CA02

Claims (3)

[Claims] 1. A magnetoresistive effect reproducing head comprising an upper shield film, a lower shield film, a magnetoresistive effect film, and an electrode film electrically connected to the magnetoresistive effect film, and a magnetoresistive effect reproducing head. Recording / reproducing separation including an inductive thin film recording head including a lower magnetic pole film, a recording gap film, an upper magnetic pole film, and a coil formed adjacent to each other, and a protective film formed on the inductive thin film recording head. Type magnetic head, the protective film is a laminated film composed of an upper protective film and a lower protective film having a difference in chemical or physical processability, and the upper protective film is recorded on the lower protective film. A recording / reproducing separated type magnetic head having a recessed step formed on the air bearing surface facing the medium. 2. The recording / reproducing separated type magnetic head according to claim 1.
The upper protective film is Al₂O ₃Is a film made of
The lower protective film is made of Al₂O₃From a compound whose main component is
Recording / reproducing separated type magnetic head.
De. 3. The recording / reproducing separated type magnetic head according to claim 2.
In the above, the lower protective film is Al ₂O₃SiO₂, Al₂O₃Zr₂O
₃, Or Al₂O₃Y₂O₃From at least one of
Recording / reproducing separated type magnetic head.
De.