JPS6025016A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To reduce the resistance of a coil circuit and perform excellent recording and reproduction by forming the coil circuit of a thin film made of copper or its alloy, and forming a thin film of aluminum or its alloy on its one surface. CONSTITUTION:The coil circuit 3 made of copper or its alloy is laminated spirally on a lower magnetic body layer 1, and a quartz glass layer 2 constituting a magnetic gap 2 is laminated thereupon. Further, an upper magnetic body layer 5 is laminated and a low-fusion-point glass layer 7 is laminated thereupon. Then, a thin film 4 made of Al or its alloy is formed on one or both surfaces of the thin-film coil 3 to a thickness <=1/2 as large as that of the copper film. This constitution never causes layer separation, etc., due to high temperature for the annealing of magnetic poles or for depositing a protection plate on a head substrate. Further, a chemical reaction is caused on the interface between the surface oxidized layer of the Al layer and insulating layer to form a stabilized layer. Furthermore, an interlayer insulation defect due to the diffusion of copper ions on the interface between the Al layer and copper alloy layer is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a thin film magnetic head, and more particularly to a thin film magnetic head formed by laminating a thin film loop circuit and a magnetic thin film on a substrate.

Prior art Thin-film magnetic heads like this can have a high driving frequency, and because they are composed of thin films, they can be made smaller and more dense than bulk-type magnetic heads, and they can be easily installed in multi-I racks. In recent years, there has been much research into practical application. Thin-film magnetic heads are also effective for multi-track magnetic heads in perpendicular magnetic recording systems, and this multi-track system allows many pieces of information to be recorded and reproduced at the same time.

Such thin-film magnetic heads are usually made by forming a wire loop circuit for passing a recording current on a substrate such as ferrite by vacuum thin film deposition or plating, an insulating thin film to insulate the wire loop circuit, a magnetic layer, etc. A magnetic head is configured.

In this type of thin-film magnetic head, aluminum alloys have been widely used for the wire circuit as in general bond circuits, but in recent years, the processing temperature in the post-process of thin-film magnetic heads has increased from 4.50°C to 650°C. Since the temperature is as high as ℃, there is a drawback that oxidation of the aluminum alloy and diffusion phenomenon to adjacent layers progresses. Furthermore, processing temperatures above the transformation point of aluminum cause recrystallization of aluminum, which causes deformation and stacking of microcrystals on the surface, resulting in peeling at the interface. .

Accordingly, it is an object of the present invention to provide a thin film magnetic head which eliminates such conventional drawbacks, reduces the resistance of the coil circuit, and enables good recording and reproduction.

An embodiment of the present invention is illustrated in FIG. 1, and what is indicated by the reference numeral 1 in the figure is a lower magnetic layer made of a soft magnetic material such as ferrite, which becomes the lower magnetic pole. A coil circuit 3 made of copper or a copper alloy is spirally laminated on the body layer 1, and a quartz glass layer 2 which insulates the coil circuit and forms a magnetic gap 2 is further laminated thereon. Further, an upper magnetic layer 5 serving as an upper magnetic pole is formed across the wire circuit 3.
A protective plate 6 and a low melting point glass layer 7 for welding the protective plate 6 to the head are laminated thereon to form a thin film magnetic head.

In the above configuration, a thin film layer 4 made of aluminum or an aluminum alloy is formed on one or both surfaces of the thin film coil 3. Further, the lower magnetic material 51 and the upper magnetic material layer 5 may be made of permalloy, sendust, super sendust, amorphous magnetic material, or the like.

In such a configuration, by flowing a recording current through the coil circuit 3.4, magnetic flux flows back to the upper magnetic material M5 and the lower magnetic material layer 1, and a magnetic field is generated in front of the head (on the right side in the drawing) from the magnetic gap 2. and magnetizes the recording medium. Further, during reproduction, the magnetic flux flowing into the gap 2 from the recording medium circulates through the upper magnetic layer 5 and the lower magnetic layer 1, induces a current in the wire loop circuit 3, and reproduces a signal.

Conventionally, in such a configuration, the aluminum coil was heated adjacent to the aluminum coil due to the high temperature (670°C) during annealing of the magnetic pole after the completion of film formation and the high temperature of 490°C to 540°C for welding the protective plate to the head substrate. However, since the wire of the present invention is made of copper or copper alloy, it has higher heat resistance than aluminum wire and does not cause phenomena such as layer peeling. . In this case, since the diffusion coefficient of copper ions in the medium is large, there is a risk that the interlayer insulation will be poor and the yield will be reduced. By providing this, a chemical reaction occurs at the interface between the surface oxidized layer of the aluminum layer and the insulating layer, and a stabilizing layer can be formed. Furthermore, since an alloy reaction layer was formed at the interface between the aluminum layer and the copper alloy layer, there was no defect in interlayer insulation due to diffusion of copper ions.

Furthermore, since the bond between the aluminum layer and the insulating layer is stronger than the bond between the copper alloy and the insulating layer, the present invention can solve the problem of poor interface bonding. Moreover, the aluminum layer 4 in the present invention has a conventional thickness of 1 μm.
Unlike aluminum wire wiring with a thickness of 5μ, the film thickness is 100μ
Since it is between 0 and 3000, it combines on the surface of the copper alloy layer and becomes a stable substance that will not generate abnormal crystals or change in volume even during the hot process during the head manufacturing process, and will not diffuse into the copper wire ring. This makes it possible to minimize the wiring resistance, prevent an increase in wiring resistance, and make copper alloy wire wire wiring more effective.

Other Embodiments FIG. 2 shows another embodiment of the present invention.
In the figure, the same parts as in the first embodiment are designated by the same reference numerals, and the explanation thereof will be omitted.

In this embodiment, an aluminum or aluminum alloy layer 8 is provided only on the lower or upper portion of the copper alloy wire ring 3 to provide interlayer insulation and interlayer bonding on each surface. In the embodiment shown in FIG. 2, a thin film layer 8 of aluminum or aluminum alloy is formed on both sides of the wire ring 3 and alternately in two or lower layers. In this case, the copper alloy wire ring 3 is processed by photolithographic micromachining or the like, and after it is formed, an aluminum thin film is formed on the entire surface, and only the aluminum thin film 8 is oxidized by a surface oxidation method.

It has been found that the same effect as shown in FIG. 1 can be obtained in this embodiment as well.

In the above two embodiments, it is preferable that the thickness of the aluminum or aluminum alloy thin film is less than or equal to the thickness of the copper or copper alloy thin film.

Effects As explained above, according to the present invention, a thin film of copper or a copper alloy is used as the metal forming the ring circuit of a thin film magnetic head, and a thin film of aluminum or an aluminum alloy is formed on at least one surface of the thin film. As a result, diffusion of copper ions can be prevented, and the bonding between the insulating layer and the quartz glass can be improved, and the yield of thin-film magnetic heads equipped with copper alloy wire wheels has been significantly improved.

Furthermore, by using copper alloy wiring, etching accuracy was improved compared to conventional aluminum wiring, wire mounting density was increased, and the number of windings could be increased, thereby increasing the reproduction output of the magnetic head.

Furthermore, by using copper alloy wiring, wiring resistance can be reduced, which reduces circuit loss and improves recording and reproducing efficiency.

An example of wiring resistance is 2.7Ω for aluminum wiring.
, thickness 3.9#=-'13μm1 length 4100'p-
In the case of copper alloy wiring, the resistance is 1.82Ω, the thickness is 4.1cm, and the width is 15mm. um, and the length was 4100 μm.

[Brief explanation of the drawing]

Each figure shows an embodiment of the present invention; FIG. 1 is a sectional view showing the structure of the first embodiment, and FIG. 2 is a sectional view showing another embodiment.

Claims (1)

[Scope of Claims] l) A thin film magnetic head comprising a thin film wire loop circuit and a magnetic thin film laminated on a substrate, wherein the wire loop circuit is a thin film made of copper or a copper alloy, and at least one surface of the thin film is coated with aluminum or A thin film magnetic head characterized by forming a thin film made of an aluminum alloy. 2) The thickness of the above 7 aluminum or aluminum alloy thin film is the same as that of copper or copper alloy thin j1! ! 2. The thin film magnetic head according to claim 1, wherein the thin film magnetic head has a thickness of less than or equal to .