JPH05128424A - Production of laminated magnetic head - Google Patents

Abstract

PURPOSE:To prevent the reaction of bonding glass and magnetic metallic film and to obviate the degradation in the efficiency of a magnetic core by forming a protective film on the surface of a coil winding groove. CONSTITUTION:The magnetic core 2 is formed on a nonmagnetic substrate Ia by forming the films of a 1st layer 3a consisting of the magnetic metallic material,' such as Fe-Al-Si alloy and a 1st layer 4a consisting of an insulator, such as SiO2, and respectively having 3mum, 0.2 to 0.5mum thicknesses on this substrate and repetitively forming the films of a 2nd layer 3b consisting of the magnetic metallic material, the 2nd layer 4b consisting of the insulator, the 3rd layer 3c consisting of the magnetic metallic material and the 3rd layer 4c consisting of the insulator. The nonmagnetic substrate 1b which serves as a reinforcing material is then adhered by adhesive glass 5 to the 3rd layer 4c, by which a magnetic core block 6 is formed. The block 6 is then so cut as to intersect orthogonally with the laminated films. The coil winding groove 7 is formed on the one side of the substrate 1b and the protective film 8 is formed of SiO2, etc., at 1mum thickness on the groove 7. The opposite surface is worked to a specular surface and the protective film 8 is removed from the opposite surface. The SiO2, etc., is then formed on the opposite surface as a gap material 9 and is welded by bonding glass 10; thereafter, the cut block is regulated to the shape meeting applications. The laminated magnetic head is thus formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a laminated magnetic head which can be used in various magnetic recording / reproducing devices.

[0002]

2. Description of the Related Art In a conventional magnetic head, a magnetic core such as a magnetic material such as ferrite or a magnetic metal material is manufactured by grinding, lapping or other mechanical processing, and the magnetic core is adhered while forming a magnetic gap and wound. The line was applied to form a magnetic head. However, with the recent trend toward smaller size and larger capacity in external storage devices for computers and VTRs, there is a demand for improvement in linear recording density and areal recording density. In order to achieve this, the recording medium has a high coercive force, which makes it possible to improve the output of recording and reproducing signals at short wavelengths. On the other hand, a technique has been proposed for forming a magnetic core of a magnetic head with a metal magnetic material having a high saturation magnetic flux density in order to sufficiently perform saturation recording on a high coercive force medium. For example, a magnetic metal block having a sufficiently high saturation magnetic flux density and an insulator such as SiO ₂ are formed into thin films by a method such as sputtering or vapor deposition and alternately laminated, and both surfaces thereof are sandwiched by nonmagnetic substrates to form a magnetic core block. An example is a laminated magnetic head in which a magnetic core is manufactured from a magnetic core block. A conventional example of the laminated magnetic head will be described below with reference to FIG.

FIG. 4 (a) shows a magnetic core 2 on a non-magnetic substrate 1a, which is a metal magnetic material such as Fe-Al-Si alloy, amorphous magnetic alloy or Fe-Ni alloy having a high saturation magnetic flux density and a high magnetic permeability. The first layer 3a and the insulator first layer 4a such as SiO ₂ and Al ₂ O ₃ are sequentially deposited by a sputtering method, and thereafter, the metal magnetic second layer 3b, the insulator second layer 4b, and the metal magnetic first layer are formed. 3 layers 3c,
The magnetic core 2 is formed by repeatedly film-coating with the third insulator layer 4c. Next, the non-magnetic substrate 1b serving as a reinforcing material is attached to the insulating third layer.
The magnetic core block 6 is manufactured by adhering it to the layer 4c with the adhesive glass 5 (FIG. 4B). Next, the magnetic core block 6 is cut and separated so as to be orthogonal to the laminated film, and the coil wire wound groove 7 is formed on at least one of the one non-magnetic substrates by a grinding process (FIG. 4C). After that, the opposite surface is mirror-finished by the Lap method or the like, and the Gap material 9 such as SiO _{2 is} formed thereon by the sputtering method (FIG. 4D). In this case, a layer having a film thickness equal to or smaller than that of the facing surface is also formed in the coil winding groove 7. After that, the bonding glass 10 was welded and adhered to the magnetic head as shown in FIG. 4 (e), and the shape and the gap depth were regulated according to the application to obtain a magnetic head. FIG. 4 (f) showing a floating head used in a hard disk as an example.
Since the magnetic core 2 of the laminated magnetic head is composed of the metal magnetic film 3 having a high saturation magnetic flux density and a high magnetic permeability, the magnetic permeability is less deteriorated in the high frequency band and the inductance can be reduced as compared with the conventional magnetic head. .. Further, by increasing the saturation magnetic flux density of the metal magnetic film 3, it is possible to cope with recording of a high coercive force medium, and by utilizing the excellent characteristics of the metal magnetic film, many advantages can be expected as compared with the conventional magnetic head.

[0004]

However, the above-mentioned conventional laminated magnetic head has been reduced in size and increased in capacity in recent years, and has a relationship such as a coercive force of the magnetic recording medium and a spacing between the magnetic head and the magnetic recording medium. Therefore, the Gap depth tends to be small. Especially in hard disk drives, the Gap depth of the magnetic head is around 5 μm. Gap depth is 20μm to 30 like conventional VTR head
Unlike stacked magnetic heads with μm, the recent Ga
In a stacked magnetic head having a small p-depth, as shown in FIG. 5, in a region having a small Gap depth, recording / reproducing characteristics are significantly deteriorated as compared with a conventional ferrite-based head, and the output of the stacked magnetic head is a ferrite-based head. There is a problem in that the noise becomes smaller than the output of the signal, the noise of the baseline of the isolated waveform increases, and the S / N ratio remarkably decreases. In a laminated magnetic head that needs to have a small Gap depth, it is important to control the characteristics in the region of a small gap depth, so it is necessary to solve the above problems. The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a method of manufacturing a laminated magnetic head that exhibits good characteristics without variations even with a small Gap depth.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention uses SiO ₂ as a protective film on the surface of a coil winding groove,
Insulating oxides such as ZrO ₂ and Al ₂ O ₃ and nitrides such as SiN have sufficient performance to prevent them from reacting with the bonding glass.
This is a structure of a laminated magnetic head including a protective film having a film thickness.

[0006]

Therefore, according to the present invention, in the conventional method of manufacturing a laminated magnetic head, when the gap is formed, as shown in the cross-sectional view of the magnetic core of FIG. 2 reacts with the metal magnetic film 3 forming 2 to form a reaction layer 11 that does not exhibit the original soft magnetic characteristics,
It was found that, unlike the conventional ferrite head, the laminated magnetic head in which the magnetic core is composed of only the metal magnetic film has a bad effect on the reproduction efficiency of the magnetic core and the generation of noise. Further, when processing the magnetic head, the gap is applied from the side surface of the magnetic core block.
Although the depth value is read and processed, the Gap depth 12 on the non-magnetic substrate when reading from the side is an apparent value, and the Gap depth of the metal magnetic film forming the magnetic circuit is as shown in FIG. In the cross-sectional view of the magnetic core, when the predetermined gap depth value is regulated from the side due to the presence of the reaction layer 11, the value is different from the substantial gap depth of the metal magnetic film, and the dimensional variation also occurs. It was happening. With the above configuration, the reaction between the bonding glass and the metal magnetic film is prevented by forming the protective layer on the surface of the coil winding groove,
Accurate Ga with excellent electromagnetic conversion characteristics without variation
It is possible to manufacture a laminated magnetic head capable of controlling the p depth.

[0007]

FIG. 1 shows a method of manufacturing a laminated magnetic head according to an embodiment of the present invention. FIG. 1A shows a magnetic core 2 on a non-magnetic substrate 1a, a Fe-Al-Si alloy having a high saturation magnetic flux density and a high magnetic permeability, an amorphous magnetic alloy,
First layer 3a of metallic magnetic material such as Fe-Ni alloy and SiO ₂ , Al ₂
An insulating first layer 4a such as O _{3 is} deposited by a sputtering method to a thickness of 3 μm and 0.2 to 0.5 μm, respectively, and thereafter, a metal magnetic second layer 3b, an insulating second layer 4b, and a metal magnetic third layer. The magnetic core 2 is formed by repeatedly forming a film with 3c and the third insulating layer 4c. Next, the non-magnetic substrate 1b serving as a reinforcing material is adhered to the third insulator layer 4c by the adhesive glass 5 to bond the magnetic core block 6
Figure 1 (b). Next, the magnetic core block 6 is cut and separated so as to be orthogonal to the laminated film, and the coil wire wound groove 7 is formed on at least one of the pair of non-magnetic substrates by grinding, as shown in FIG. 1 (c). These are the same as the conventional configuration. afterwards,
In the present invention, a protective film 8 serving as a protective layer is formed on the coil winding groove 7 by sputtering to a thickness of about 1 μm.
(d). As the material, an insulating oxide such as SiO ₂ , ZrO ₂ , Al ₂ O ₃ or a nitride such as SiN is used. The optimum material and film thickness are selected according to the type of bonding glass to be welded during Gap formation. Bonding glass used for Gap formation with a low melting point in recent years contains a large amount of metal elements such as Pb and easily reacts with a metal magnetic film, so that the thickness of the protective film needs to be sufficiently large. Further, depending on the type of metal magnetic film used, it is necessary to select the material to be used in consideration of matching with the material forming the protective layer.
After that, the opposite surface is mirror-finished by the Lap method or the like.
(e). At this time, the protective film 8 applied in the previous step is completely removed from the facing surface so that the protective film 8 remains only in the coil winding groove. After that, as the Gap material 9, SiO ₂ , Al ₂
O ₃ or the like is formed on the opposite surface by a sputtering method to a gap length of about 0.3 μm to 1.0 μm, as shown in FIG. At this time, the coil winding groove is formed with a protective layer having a film thickness larger than that of the Gap material 9. After that, when the bonding glass 10 is welded, the reaction between the metal magnetic film 3 and the bonding glass 10 is prevented. Then G
Adhesion is performed while forming a magnetic gap so as to sandwich the ap material.
(g), FIG. 1 (h) in which the laminated magnetic head is formed by controlling the shape and gap depth according to the application. In the conventional technique, there is no protective film and only the Gap material 9 functions as a protective material. However, since the Gap material is thin, the reaction layer 11 of the metal magnetic film 3 and the bonding glass 10 is formed, and the electromagnetic conversion characteristics are deteriorated. However, there is a problem that the actual value of the gap depth cannot be grasped, but in this embodiment, the gap layer can be accurately controlled because the reaction layer is not formed. Further, it is possible to prevent the efficiency from decreasing due to the reaction layer. As an example, an Al ₂ O ₃ protective film of 1 μm is formed in the coil winding window, and a Gap material of SiO ₂ is 0.3 μm after lapping the facing surface.
When the laminated magnetic head was formed at the gap formation temperature of 550 ° C. after the film was formed by the sputtering method, the laminated magnetic head in which the bonding glass and the metal magnetic film did not react could be formed. FIG. 2 shows the correlation between the Gap depth value and the normalized output value of the laminated magnetic head and the ferrite type head manufactured in this embodiment. The multi-layer magnetic head manufactured according to the example is a multi-layer magnetic head having a small recording efficiency and a good recording / reproducing characteristic because it is composed of a magnetic core made of a metal magnetic film having no reaction layer. Therefore, the output of the conventional ferrite-based head does not become lower than the output even in the region where the Gap depth is small.

[0008]

As is apparent from the above embodiments, the present invention serves as a protective film on the surface of the coil winding groove of the laminated magnetic head as an insulating oxide such as SiO ₂ , ZrO ₂ , Al ₂ O ₃ or SiN. By forming a protective layer with sufficient performance so that it will not react with the bonding glass by the nitride, the reaction between the bonding glass and the metal magnetic film is prevented, and the original magnetic circuit of the metal magnetic film without the reaction layer is formed. Since it is possible to manufacture the laminated magnetic head having the structure, the Gap depth can be accurately controlled, and the magnetic head having excellent characteristics can be provided without the efficiency of the magnetic core being lowered by the reaction layer.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a method of manufacturing a laminated magnetic head according to an embodiment of the invention.

FIG. 2 is a diagram showing a relationship between Gap depth and standardized output of a laminated magnetic head and a ferrite head according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view of the configuration of a conventional laminated magnetic head.

FIG. 4 is a diagram illustrating a method of manufacturing a conventional laminated magnetic head.

FIG. 5 is a relational diagram of Gap depth and standardized output of a conventional laminated magnetic head and a ferrite-based head.

[Explanation of reference numerals] 1a, 1b ... Non-magnetic substrate, 2 ... Magnetic core, 3a, 3b,
3c ... Metallic film, 4a, 4b, 4c ... Insulating film, 5 ... Adhesive glass, 6 ... Magnetic core block, 7 ... Coil winding groove, 8 ... Protective film, 9 ... Gap material, 10 ... Bonding glass, 11 ... Reaction layer, 12 ... Gap depth.

Claims (2)

[Claims] 1. A laminated film in which a metal magnetic film and an insulating film are alternately laminated on a pair of non-magnetic substrates to form a laminated film, and a coil winding groove is formed on at least one of the pair of non-magnetic substrates. A method of manufacturing a laminated magnetic head, wherein a protective film is formed on a surface of the coil winding groove in the laminated magnetic head that is adhered while forming a magnetic gap so as to be sandwiched by. 2. An insulating oxide such as SiO ₂ , ZrO ₂ , Al ₂ O ₃ or a nitride such as SiN is used as a material for the protective film formed on the surface of the coil winding groove. The method of manufacturing a laminated magnetic head according to claim 1.