JPH06274826A - Composite type magnetic head and manufacture of it - Google Patents

Abstract

PURPOSE:To provide a magnetic head capable of recording with high density by forming a magnetic circuit with a slider substrate incorporating a first magnetic core and a second magnetic core upward and backward the substartrate and rotating the backward magnetic core with a thin film core. CONSTITUTION:A magnetic head is constituted of a slider structure arranging a pair of side rails 3 on both sides of the slider, and the magnetic core 1 of a soft magnetic thin film is arranged backward on the side rail 3 of one side, and a magnetic gap 2 is placed on the minimum floating position backward the side rail 3. All front side of the slider is made of nonmagnetic material, and the magnetic core 1 forms the minimum magnetic circuit to be placed backward the slider. The medium opposing surface and the rear surface of an opposite side of the slider substrate are arranged so that a rear surface magnetic core 21 made of the soft magnetic thin film is in contact with the magnetic core 1 perpendicularly, and further, a thin film coil 22 is formed out of a thin film so as to rotate the rear surface magnetic core 21. The height of the first magnetic core 1 is about 0.2mm, and the coil 22 and the core 21 are formed on the top part of the core 1, and a protection film 23 is formed on the top part of the coil 22 and the core 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used in a magnetic disk device and a manufacturing method thereof.

[0002]

2. Description of the Related Art As magnetic disk devices have become smaller and have larger capacities year by year, the demand for high density recording is extremely large. Conventionally, a magnetic head used in a magnetic disk device is a monolithic head in which ferrite forms a magnetic core, or an extension of the monolithic head, and a soft magnetic thin film, generally a FeAlSi-based alloy soft magnetic thin film, is arranged near the magnetic gap. A MIG head with improved recording capability and a thin film magnetic head in which all of the magnetic core and coil are formed by a thin film forming technique are used. Each has its own characteristics, but the demands for higher density and smaller size of the magnetic disk device require the following items for the magnetic head. (1) Improvement of S / N ratio: High reproduction output per track and low impedance noise (necessarily low inductance, low resistance). (2) Broadband frequency characteristics: Low inductance and wide frequency characteristics of magnetic permeability of the material. (3) A narrow track is possible. (4) Low levitation. (5) The slider is small.

With respect to these conditions, the thin film magnetic head is promising, and in the trend of increasing the density, the proportion shown in the market is increasing. Furthermore, recently, a laminated magnetic head (H
A magnetic head for a DD (hard disk drive) has been proposed. A magnetic head for an HDD is promising as a magnetic head that satisfies the high density condition, though it can be manufactured by conventional processing techniques. Also, in response to the demand for miniaturization of magnetic disk devices and the reliability at the time of low flying, the miniaturization of sliders has progressed, and 70% and 50% of conventional sliders have been developed.
Commercialization of sliders with a similar ratio is ongoing.

Since the thin-film magnetic head uses a soft magnetic thin film, it has good high frequency characteristics of magnetic permeability and is capable of high-speed data transfer or high-density recording. In the thin film magnetic head, an electromagnetic conversion element (thin film magnetic head in a narrow sense) is formed on the rear end surface of a non-magnetic material that serves as a slider for flying. Such a conventional magnetic head has a sectional structure as shown in FIG. 4, and a magnetic gap 33 is formed on a substrate having a first insulating layer 35 made of Al ₂ O ₃ material on the surface. The lower core 31 and the upper magnetic core 32 are deposited via the above to form a magnetic circuit, and a coil layer is formed with an insulating layer in between so as to rotate the magnetic core. The inter-coil insulating layer 36 insulates the coils from each other and alleviates a step caused by manufacturing the coils. In addition, since the process is easy, organic materials
A (resist) is generally used, and is cured by heat treatment. In the case of a two-layer coil layer, the number of layers of the organic insulating layer is 3 to 6 layers.

The manufacturing process of the thin film magnetic head will be described with reference to FIG. A wafer substrate 300 made of a non-magnetic material having a large diameter is made into a mirror surface, an Al ₂ O ₃ thin film or the like is formed as an insulating layer 35 on the upper surface of the wafer substrate 300 to have a thickness of about 10 μm, and the mirror surface is smoothed again. A NiFe alloy thin film or the like is plated as the lower magnetic core 31 on the substrate thus formed and patterned into a predetermined shape. A non-magnetic material having a predetermined thickness is formed on the upper portion as a magnetic gap 33. Further, an organic film having a thickness of 2 to 3 μm is formed thereon as a second insulating layer for the core and coil layers,
Pattern to the required formation. Two coil layers are formed on these layers, and a resist made of an organic material is filled between the coils. Further, a NiFe alloy thin film or the like is formed into a predetermined shape as the upper magnetic core 32. A thick Al ₂ O ₃ thin film is formed as an upper protective layer 37 of the thin film magnetic head on the upper magnetic core 32, and the process is completed. The organic film resist used as the insulator of the thin film magnetic head is solidified at a temperature of about 250 ° C. In this example, the coil is composed of two layers, so it is cured at 250 ° C. three to six times.

On the other hand, recently, a magnetic head for HDD (hard disk drive) has been proposed, which is a laminated magnetic head, although it can be manufactured by conventional processing techniques.
It is promising as a magnetic head that satisfies the high density condition. In a laminated magnetic head, a soft magnetic thin film forming a magnetic core is sandwiched by a non-magnetic substrate and processed into a slider structure for a magnetic disk device for HDD. As shown in FIG. 6, the slider has an air bearing surface having a pair of rails 3, and a magnetic core formed of a magnetic film substantially in the center of the two side rails 3 over the entire length of the side rails. 1 exists, and the magnetic gap 2 for recording / reproducing is located behind the side rail. The slider groove rear end portion 5 located at the center between the side rails and deeper than the air bearing surface is processed from the slider rear end to a position substantially near the magnetic gap 2 (coil punching).

In the manufacturing process, as shown in FIG. 7, a soft magnetic thin film 101 of FeAlSi or the like is formed to a desired thickness on one surface of a non-magnetic substrate 100 serving as a slider material. This thickness forms the track width of this type of magnetic head and is an important parameter. After forming the soft magnetic thin film, another non-magnetic substrate is bonded. A plurality of soft magnetic thin films are collected to form one core ingot 102. Two bars adhered via the magnetic gap, a front core bar (L core bar) 106 and a rear core bar (T core bar) 1
07 is cut out from this core ingot 102, and the surface facing the magnetic gap portion is mirror-finished to form a gap. This gapped bar 109 is divided into individual sliders so that the magnetic core 1 is located on one side rail 3 of the slider, and is finally made into a slider through steps such as coil removal and mirror surface lapping of the air bearing surface. It

[0008]

In such a conventional thin film magnetic head or laminated magnetic head, there is a limit to the miniaturization of the slider due to the reduction in inductance and the reduction in flying height. That is, in the case of the laminated magnetic head, it is necessary to reduce the winding diameter of the winding for low inductance.
Therefore, the winding portion 9 of the rear magnetic core 1 to be wound is made smaller, and the width of the core portion at the rear end of the side rail is made smaller from the slider front surface to the slider back surface. A structure that does However, this structure reduces the bond area in the magnetic gap, making it impossible to maintain sufficient magnetic gap bond strength to wind the coil. Moreover, the coil wound around the core may rise to the air bearing surface, resulting in poor reliability. In any case, since a winding wire is not a thin film but a bulk wire material, the winding volume is larger than necessary compared with a conventional thin film magnetic head, and it is difficult to reduce the size and the inductance. In the case of a thin film magnetic head, it is necessary to narrow the width of the shape of the magnetic core used for low inductance. However, in order to ensure normal operation, it is necessary to increase the magnetic anisotropy, and as a result, the effective reproduction efficiency decreases, which is not desirable.

The miniaturization of the slider is to reduce the height of the slider as much as possible with the miniaturization and thinning of the device. It is being commercialized from the conventional height of about 4 mm to the current height of 2 mm. In addition, it is an indispensable condition for low flying height and high-speed access. By reducing the size of the slider, its mass is reduced, the flying height variation is small, and it is possible to achieve high reliability such as reducing the impact at the time of contact with the magnetic disk. However, the conventional magnetic head has a limit, and it is said that the limit is up to 50% of the mini slider. These problems are high density, low levitation,
This limits the reduction in inductance. The present invention solves the above problems, and an object of the present invention is to provide a composite magnetic head capable of high density recording and a method for manufacturing the same.

[0010]

In order to achieve the above object, the present invention provides a slider substrate including a first magnetic core composed of two magnetic cores adhered via a magnetic gap, and a slider substrate above the slider substrate. A magnetic circuit is formed from a rear second magnetic core that is formed substantially parallel to the medium facing surface that joins the first magnetic core, and a thin film coil rotates the rear magnetic core.

[0011]

With the above-described structure, the present invention can realize a compact magnetic head for a magnetic disk device capable of high density recording.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. As shown in FIG. 1A, the magnetic head has a slider structure in which a pair of side rails 3 are arranged on both sides of the slider, and a magnetic core 1 made of a soft magnetic thin film is arranged behind one side rail 3. Therefore, the magnetic gap 2 is located at the rear of the side rail 3 at a substantially minimum flying position. The front part of the slider is entirely made of a non-magnetic material, and the magnetic core 1 is designed to form a minimum magnetic circuit, and is placed on the rear part of the slider. As shown in FIG. 1B, on the back surface of the slider substrate thus formed opposite to the medium facing surface, the back magnetic core 21 made of a soft magnetic thin film is vertically contacted with the magnetic core 1. It is distributed. The thin-film coil 22 is formed of a thin film so as to rotate the back surface magnetic core 21. The sectional structure including the magnetic core 1 has the structure shown in FIG. The height of the first magnetic core 1 is only about 0.2 mm, the thin film coil 22 and the back magnetic core 21 are formed on the upper portion thereof, and the protective layer 23 is formed on the upper portion thereof. The thickness of the layer formed in the thin film process is at most 0.04 mm
It is very thin and the size of this slider is 1mm in length and width.
It is an ultra-compact magnetic head with a height of 0.75 mm and a height of 0.21 mm and 50% of the slider.

FIG. 2 shows the method of manufacturing this magnetic head.
Will be explained. Non-magnetic substrate for slider material
A soft magnetic thin film 101 of FeAlSi or the like is formed on one surface of 100 to a desired thickness. At this time, between the substrate and the lower surface of the soft magnetic thin film, a diamond-like carbon film having a thickness of 200 nm is formed as a base adhesion layer by the CVD method. The soft magnetic thin film is
It is formed of a two-layer film having a diamond-like carbon of 100 nm as an intermediate layer and a thickness of 7 μm. This thickness defines the track width of this type of magnetic head and is an important parameter. After forming the soft magnetic thin film,
Diamond-like carbon is deposited as the upper protective layer under the same conditions as the lower adhesive layer. After that, a low-melting-point glass thin film is formed on the upper protective layer serving as an adhesion surface, and another nonmagnetic substrate is heat-treated and adhered. At this time, a plurality of soft magnetic thin films are collected to form one core ingot 102. Two bars, a front core bar (L core bar) 106 and a rear core bar, which are bonded via a magnetic gap.
(T core bar) 107 is cut out from this core ingot 102. After that, a winding groove is formed on each bar, and a surface facing the magnetic gap portion is mirror-finished to form a gap. The thickness of the front core bar 106 is substantially equal to the thickness of the rear core bar 107, and a non-magnetic slider core bar is additionally written to form a gap between the front core bar 106 and the rear core bar 107 in order to make a predetermined slider have the same length. At the same time, it is adhered with a glass thin film.

Thereafter, the core portion at the rear of this gapped bar is removed and the magnetic circuit is opened. The back surface of the slider is mirror-finished through grinding and lapping processes. An Al ₂ O ₃ thin film is formed on the back surface thereof as an insulating layer for the first magnetic core 1 and the thin film coil 22 to a thickness of ₂ to 3 μm, and a pattern is formed into a required shape. If air bubbles are present in the glass mold portion between the magnetic cores, a resist is filled to maintain a smooth surface. Therefore, there is no problem in the subsequent steps and the yield does not deteriorate. Two coil layers are formed on the upper part, and a resist made of an organic material is filled between the coils.
The resist used as an insulator is solidified at a temperature of about 250 ° C. In this embodiment, the coil has two layers, so 2
Once solidified at 250 ° C. Since the magnetic core 1 of the embodiment uses sendust, the characteristics are not deteriorated by this heat treatment. After the coil layer is formed, the back magnetic core is
An iFe alloy thin film or the like is plated and formed into a core pattern to form a closed magnetic circuit with the first magnetic core 1. An upper protective layer is formed on the upper portion by sputtering, and the process is completed.

The gapd bar is divided into individual sliders so that the magnetic core 1 is located on one side rail 3 of the slider, and finally a slider structure is formed through processes such as mirror-wrapping of the air bearing surface. . The shape of the slider is
As shown in FIG. 1, it has an air bearing surface consisting of a pair of side rails 3, and the reproducing magnetic gap 2 is located behind the side rails 3. The slider groove located in the center between the side rails and deeper than the air bearing surface is shallowly machined to the slider rear end.
Up to the formation of the gap, a process similar to that of the rear of the conventional stacked magnetic head is performed, and only a thin film process is added to the coil and the back core. The process of manufacturing the thin film coil and the back core may be performed for each bar or for a block in which a plurality of bars are bonded. Recently, an exposure apparatus based on shape recognition has been sold, and the above process can be facilitated.

As Comparative Example 1, the conventional laminated magnetic head shown in FIG. 6 and the thin film magnetic head shown in FIG.
Used as. Table 1 shows a comparison of each performance. Each value is standardized with the value of the embodiment.
In Comparative Example 1, the winding is not a thin film and it is difficult to reduce the inductance. In Comparative Example 2, although the inductance can be reduced to some extent, the output is low. In both comparative examples, it is difficult to reduce the size of the slider as compared with the examples, and it is far from meeting the demand for the size reduction of the magnetic disk device. From these facts, the magnetic head according to the present invention is an excellent magnetic head as a whole.

[0017]

[Table 1]

In the laminated magnetic head, the winding is not a thin film, and a conductor wire of 0.02 to 0.03 mm is wound around the winding portion.
It is necessary to make the volume of the wound portion larger than a predetermined size, and the miniaturization of the slider is limited to a 50% slider with a length of 2 mm, and it is difficult to increase the number of windings. In addition, a part of the winding wire provided on the core may protrude from the air bearing surface, and the reliability between the head media may be impaired. In a general magnetic head manufacturing process, a bobbin is fixed to a core of a winding portion, and the bobbin is wound to prevent the winding from protruding from an air bearing surface. However, this method increases the winding diameter, deteriorates the inductance, and deteriorates the recording / reproducing performance.

In the case of the thin film magnetic head, a predetermined area is required because the magnetic core and the coil are formed in a flat shape on the rear end surface of the slider as shown in FIG. Generally, the winding area requires a lower area with a diameter of about 0.3 mm, and it will be difficult to support the miniaturization of sliders in the future. Therefore, a flat type thin film magnetic head shown in FIG. 8 is proposed. This magnetic head is a magnetic head in which a coil, a magnetic core, and a magnetic gap are formed on a medium facing surface of a slider by a thin film process. However, it is very difficult to form the magnetic gap perpendicularly and to eliminate the complicated step formed by the thin film process to obtain a flat air bearing surface. Although much research has been done, it has not yet been put to practical use.

Further, an embodiment of the present invention will be described in detail. A conventional magnetic core 1 of a laminated magnetic head shown in FIG.
Is arranged almost at the center of the side rail 3 and has a length substantially equal to the length of the slider. This structure is unnecessary for the magnetic circuit of the magnetic head, and has high inductance for reproduction efficiency and is unsuitable for future high density. Further, since the magnetic core 1 has a surplus portion, it may induce external noise, which is also a factor that deteriorates the recording / reproducing performance. These can be easily inferred from the difference in structure and performance between the monolithic magnetic head and the composite magnetic head. Therefore, the present invention relates to a front core having the magnetic core 1.
(L core) 6 and rear core (T core) 7 are downsized, and a slider core (S core) 8 is added in front of the slider. As can be seen from the flow of the manufacturing process in FIG. 2, this can be performed without increasing the manufacturing cost by adopting the method of simultaneously bonding the three core bars when forming the gap. The L core bar and the S core bar can be easily adhered by a method of fusion bonding using a glass thin film formed on one surface or a method of molding glass. The magnetic head having this structure has an effect of reducing the area of the recess portion of the soft magnetic thin film portion generated on the air bearing surface and improving the CSS (contact start stop) performance.

As for the miniaturization of the magnetic core 1 of the laminated magnetic head, a structure in which a core chip is glass-molded on a part of the slider can be considered as in the case of the composite magnetic head. It is also possible to construct a magnetic head in which a magnetic core bonded and reinforced with a non-magnetic material is embedded in a slider body, and then a coil and a rear core are formed on the back surface of the slider by a thin film process. Further, it is possible to easily provide a magnetic head in which an MIG type composite core chip is embedded instead of the laminated core chip. This magnetic head uses a single-crystal ferrite and a material having a high saturation magnetic flux density as a soft magnetic thin film in the gap in order to support high-density recording.

As a second embodiment of the present invention, a manufacturing process using the MIG type composite chip outlined above will be described. As shown in FIG. 3, substantially rectangular holes are periodically arranged in a large-diameter non-magnetic substrate 200. Insert the composite chip 201 into the hole and mold with glass. After that, the surface is mirror-finished, and a coil, a back magnetic core and the like are formed on the surface in the same manner as in the manufacturing process of FIG. After that, the medium facing surface on the side opposite to the back surface is mirror-finished, processed into a predetermined air bearing surface shape, and divided into each slider. This method is an effective method when the shape of the air bearing surface becomes difficult by conventional machining as the flying height decreases, and the processing can use a new method such as ion milling or powder beam.

In each of the above embodiments, an FeAlSi-based alloy thin film produced by a vacuum apparatus is used as the magnetic core. However, if the magnetic thin film has soft magnetism, the composition, the film structure, and the manufacturing method will be used. Notably, a Fe-based alloy thin film having a high magnetization density and excellent thermal stability is preferable. As the slider, there is no particular problem as long as it is nonmagnetic such as calcium titanate, forsterite, and alpha hematite.

[0024]

As can be seen from the above embodiments, the present invention has the effect that the performance of the laminated magnetic head can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view and a cross-sectional structural view of a magnetic head according to a first embodiment of the present invention as viewed from the air bearing surface and back surface.

FIG. 2 is a manufacturing process diagram of the first embodiment of the present invention.

FIG. 3 is a manufacturing process drawing of the second embodiment of the present invention.

FIG. 4 is a perspective view of a conventional thin film magnetic head (Comparative example 1).

FIG. 5 is a manufacturing process diagram of a conventional thin film magnetic head.

FIG. 6 is a perspective view of a conventional laminated magnetic head (Comparative Example 2).

FIG. 7 is a manufacturing process diagram of a conventional laminated magnetic head.

FIG. 8 is a sectional view of a planar thin-film magnetic head.

[Explanation of symbols]

1 ... Magnetic core, 2 ... Magnetic gap, 3 ... Side rail,
4 ... Slider groove, 5 ... Slider groove rear end portion, 6 ... Front core (L core), 7 ... Rear core (T core), 8 ... Slider core (S core), 9 ... Winding portion, 21 ... Rear magnetic field Core, 22, 34 ... Thin film coil, 23, 37 ... Upper protective layer,
31 ... Lower magnetic core, 32 ... Upper magnetic core, 33 ... Magnetic gap, 35 ... First insulating layer, 36 ... Inter-coil insulating layer,
100 ... Substrate, 101 ... Soft magnetic thin film, 106 ... Front core bar, 107 ... Rear core bar, 109 ... Gapped bar,
200… Non-magnetic substrate, 201… Composite chip.

Claims (6)

[Claims] 1. A rear second magnetic element for joining a first magnetic core composed of two magnetic cores adhered via a magnetic gap and the first magnetic core formed substantially parallel to a medium facing surface. A composite magnetic head, wherein a magnetic circuit is formed from the core, and the thin-film coil revolves around the rear second magnetic core. 2. The first magnetic core composed of two magnetic cores adhered via a magnetic gap is formed by adhesively reinforcing a soft magnetic thin film with a non-magnetic substrate. Composite magnetic head. 3. The composite magnetic according to claim 1, wherein the first magnetic core, which is composed of two magnetic cores bonded to each other via a magnetic gap, is formed of MIG-type single crystal ferrite. head. 4. The method of manufacturing a composite magnetic head according to claim 1, wherein the coil and the rear magnetic core are formed in a thin film process on the slider substrate having the first magnetic core. 5. A coil and a rear magnetic core are formed in a thin film process on a substrate in which the first magnetic core bonded to a non-magnetic slider substrate via a magnetic gap is embedded. The method of manufacturing the composite magnetic head according to claim 1. 6. The back substrate, on which the coil and the second magnetic core at the rear are formed in a thin film process, is bonded onto the slider substrate having the first magnetic core. Manufacturing method of composite type magnetic head.