JPH08203025A - Magnetic head and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] When manufacturing a magnetic head half, even if the groove is filled with glass, bubbles are not generated much in the glass,
A magnetic head having a good yield and a method for manufacturing the same are provided. In a magnetic head formed by joining a pair of magnetic head halves, the magnetic head halves are composed of a non-magnetic substrate, a magnetic layer disposed on the substrate to form a magnetic core, and the substrate and the magnetic layer. It is composed of a non-magnetic thin film formed above, glass filled on the non-magnetic thin film, and a thin-film coil formed on the glass portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head suitable for a video tape recorder, a video cassette recorder, a magnetic disk device and the like and a method for manufacturing the same, and more particularly, a magnetic head having a coil formed by a thin film process and a method for manufacturing the same. Regarding

[0002]

2. Description of the Related Art In recent years, high density recording of information signals has been advanced in the field of magnetic recording such as video tape recorders, video cassette recorders, magnetic disk devices, etc. Therefore, for a magnetic head that is responsible for recording and reproduction, high efficiency is achieved by downsizing the magnetic core,
Low inductance is required by thinning the coil,
Along with this, processing of the magnetic head has become complicated and precise.

In manufacturing a small magnetic head using such a thin film coil, for example, first, a groove (hereinafter referred to as a magnetic core groove) along the shape of a magnetic core is formed on a substrate made of a non-magnetic material. Is ground with a grindstone or the like to form a magnetic core forming surface. Next, a magnetic layer to be a magnetic core is formed by sputtering or the like on the substrate having the magnetic core groove formed therein. Here, the magnetic layer is not limited to a single magnetic film, and may have a laminated structure in which a plurality of metal magnetic films are laminated with an insulating film interposed therebetween in order to reduce eddy current loss. . Next, a groove for forming a thin film coil (hereinafter referred to as a winding groove) and a groove for separating the magnetic layer for each magnetic core (hereinafter referred to as a separation groove) are formed on the substrate on which the magnetic layer is formed. And) are formed by a grindstone or the like. Next, the magnetic core groove,
A low melting point glass is melt-filled in the winding groove and the separation groove to smooth the surface, and a thin film coil is formed in the glass portion so as to pass through the winding groove. As described above, a magnetic head half body having a plurality of magnetic cores and thin film coils formed on a substrate is manufactured. Then, after the pair of magnetic head halves thus manufactured are joined via a magnetic gap so that the magnetic cores face each other, the magnetic heads are cut by cutting each magnetic core into a predetermined shape. It is made.

[0004]

In the magnetic head as described above, the winding groove and the separation groove are formed by a grindstone or the like. However, in machining with the grindstone or the like, the machined surface should be sufficiently smooth. Is difficult and the machined surface becomes rough. Therefore, it is preferable to perform mirror finishing on the machined surface after machining with a grindstone or the like. However, it is very difficult to mirror-finish the processed surface of the groove, and at present, after forming these grooves, only cleaning with an organic solvent or the like is performed. Therefore, the machined surface of these grooves is
It's not smooth, but it's still rough. If such roughness remains, bubbles are generated in the glass when the glass is filled in these grooves, which is induced by the roughness.

In addition, an inert gas or the like may be incorporated in the magnetic layer formed by sputtering or the like. Then, if an inert gas or the like is taken into the magnetic layer, when the glass is filled in the magnetic core groove, the winding groove and the separation groove, the inert gas or the like taken into the magnetic layer comes out, Bubbles are generated on the glass.

Further, various solvents such as a grinding liquid used for forming the groove and wax used for fixing the substrate when forming the groove may adhere to the substrate and the magnetic layer. Then, when the glass is filled in the magnetic core groove, the winding groove and the separation groove while the various solvents or waxes are attached to the substrate or the magnetic layer, the various solvents or waxes are vaporized by the heat accompanying the filling. As a result, bubbles are generated in the glass.

The bubbles generated on the glass in this way are
This is a major factor in determining the yield of the magnetic head, which causes a short circuit or disconnection during formation of the thin film coil, roughness of the sliding surface when the magnetic head is formed, deterioration of durability, and the like.

Specifically, the cause and the ratio of defects of the magnetic head are shown in the pie chart of FIG.
Here, in FIG. 13, "short-circuit between coils due to bubbles" means that when the thin-film coil is short-circuited due to bubbles generated on the glass, "coil disconnection due to bubbles" means that the thin-film coil is disconnected due to bubbles generated on the glass. If you do, "damage due to lapping after coil formation" is
This is a case where a defect occurs due to a grinding process or the like performed after the thin film coil is formed, and “other” is, for example, a defect caused by dust mixed in during a thin film forming process for forming the thin film coil. As shown in FIG. 13, of the causes of defective magnetic heads, more than half of them are caused by bubbles generated in glass.

Therefore, the present invention has been proposed in view of such a conventional situation, and when the magnetic head half body is produced, even if the groove is filled with glass, bubbles are generated in the glass too much. It is an object of the present invention to provide a magnetic head having a good yield and a manufacturing method thereof.

[0010]

In order to achieve the above object, a magnetic head of the present invention is a magnetic head comprising a pair of magnetic head halves joined together, wherein the magnetic head halves are non-magnetic. A substrate made of a body, a magnetic layer disposed on the substrate to form a magnetic core, a non-magnetic thin film formed on the substrate and the magnetic layer, glass filled on the non-magnetic thin film, and And a thin film coil formed on the glass portion.

In the above magnetic head, alumina is suitable as the material of the non-magnetic thin film. Further, in the above magnetic head, the magnetic layer is formed to reduce eddy current loss.
It is preferable that a plurality of metal magnetic films are laminated via an insulating film.

On the other hand, the method of manufacturing the magnetic head of the present invention is
In a method of manufacturing a magnetic head formed by joining a pair of magnetic head halves, a magnetic core groove is formed by cutting a magnetic core groove on a substrate made of a non-magnetic material to form the magnetic core groove. A magnetic layer serving as a magnetic core is formed on the substrate, and a winding groove for arranging the thin film coil on the substrate on which the magnetic layer is formed, and a separation groove for separating the magnetic layer for each magnetic core. And forming a non-magnetic thin film on the substrate and the magnetic layer on which the winding groove and the separation groove are formed, filling the magnetic core groove, the winding groove and the separation groove with glass, and A thin film coil is formed in the portion so as to pass through the winding groove to fabricate a magnetic head half body.

In the above method of manufacturing a magnetic head, alumina is suitable as the material of the non-magnetic thin film. Also,
In the method of manufacturing a magnetic head, the magnetic layer is preferably formed by laminating a plurality of metal magnetic films with an insulating film interposed therebetween in order to reduce eddy current loss.

[0014]

In the present invention, since the non-magnetic thin film is formed on the substrate and the magnetic layer after the winding groove and the separation groove are formed by machining, the processed surface of these grooves can be smoothed.
Therefore, the generation of bubbles generated when filling these grooves with glass is suppressed.

Even if an inert gas or the like is taken into the magnetic layer formed by sputtering or the like, a nonmagnetic thin film is formed on the substrate and the magnetic layer, and then the magnetic core groove,
Since the winding groove and the separation groove are filled with glass, the inert gas or the like taken into the magnetic layer does not float out in the glass.

Even if various solvents or waxes adhere to the substrate or the magnetic layer, a non-magnetic thin film is formed on the substrate and the magnetic layer, and then a glass is formed in the magnetic core groove, the winding groove and the separation groove. Since these are filled, these various solvents and waxes do not vaporize and float up in the glass.

Further, in the present invention, since the substrate and the magnetic layer are covered with the non-magnetic thin film, the magnetic layer is less likely to be peeled off from the substrate, and the magnetic layer is peeled off from the substrate in the process of manufacturing the magnetic head. Without losing
Defects due to peeling of the magnetic layer are also prevented.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings.

The magnetic head manufactured in this embodiment is a magnetic head used in a video tape recorder, a video cassette recorder, etc., and as shown in FIGS. 1 and 2, a pair of magnetic head halves 10a and 10b are used. , Magnetic gap g
They are joined and integrated so as to abut each other.

Here, the magnetic head halves 10a, 10b
Is a substrate 1, a magnetic layer 2 formed on the substrate 1 and functioning as a magnetic core, a non-magnetic thin film (not shown) formed on the substrate 1 and the magnetic layer 2, and a non-magnetic thin film on the non-magnetic thin film. It has a filled glass 3 and a thin film coil 4 formed on the glass 3 portion by a thin film forming process. Then, the pair of magnetic head halves 10a and 10b are provided in the respective magnetic layers
Are abutted against each other and are joined via a non-magnetic material so that a front gap fg and a back gap bg are formed between the respective magnetic layers 2.

The magnetic head will be described in detail below through its manufacturing method.

First, as shown in FIG. 3, MnO--NiO.
A substrate 1 made of a non-magnetic material such as a system is prepared. Here, the size of the substrate 1 is, for example, about 30 mm in length and about 30 m in width.
m and the thickness is about 2 mm.

Next, as shown in FIG. 4, in order to form an inclined surface on which a magnetic core is formed, that is, a magnetic core forming surface, a plurality of magnetic core grooves 1a are formed on the substrate 1. It is formed in parallel and at equal intervals so that one of the inner surfaces becomes an inclined surface. The magnetic core groove 1a has a depth of about 130, for example, using a grinding wheel having one surface molded at about 45 degrees.
Dozens of them are formed so that the width is about 150 μm, the inclination of the inclined surface is about 45 degrees. Here, the inclination of the inclined surface is
The angle need not be 45 degrees, but is preferably about 45 degrees in consideration of the pseudo gap and the track width accuracy.

Next, the substrate 1 on which the magnetic core groove 1a is formed
As shown in FIG. 5, the magnetic layer 2 is formed thereon. Here, the magnetic layer 2 may be composed of a single magnetic film, but in order to have high sensitivity in a high frequency region, a plurality of metal magnetic films are laminated by interposing an insulating film. You had better. However, in the case where the magnetic layer 2 has a laminated structure as described above, the thickness of the insulating film needs to be such that a sufficient insulating effect can be obtained, and is made as thin as possible so that the insulating film does not act as a pseudo gap. There is a need.

Therefore, in this embodiment, the magnetic layer 2 is made of sendust (Fe-Al-Si alloy) and has a thickness of about 5 μm.
Made of alumina and a metal magnetic film of about 0.15 μm thick
And the insulating film of No. 1 were alternately laminated so that the metal magnetic film had three layers. As described above, by forming the magnetic layer 2 into a laminated structure, eddy current loss is reduced, and higher sensitivity can be obtained especially in a high frequency region.

Here, although sputtering is preferable as a method for forming the magnetic layer 2, a physical film forming method (PVD) other than sputtering, such as vapor deposition or molecular beam epitaxy (MBE), or a chemical method. Film forming method (CVD) or the like may be used.

The material of the metal magnetic film is preferably sendust, but other metal magnetic materials such as an alloy similar to sendust, a nitriding type soft magnetic alloy, and a carbonizing type soft magnetic alloy can also be used. . Also, the insulating film is not limited to alumina, and SiO ₂ , SiO, or a mixture thereof can be used.

Next, as shown in FIG. 6, the magnetic core groove 1a is formed.
Winding groove 1 for arranging thin film coil 4 at right angles to
b and a separation groove 1c for separating the magnetic layer 3 for each magnetic core are formed.

Here, as shown in FIG. 2, the winding groove 1b has a shape in which the magnetic layer 2 on the front gap side is slanted toward the front gap fg.
For example, the front gap side of the winding groove 1b is formed by a grindstone having a slope of about 45 degrees. As described above, when the magnetic layer 2 on the front gap side is narrowed toward the front gap fg, the magnetic flux is concentrated and high recording sensitivity is obtained. However, if the shape of the winding groove 1b is such that the magnetic layer 2 on the front gap side is narrowed toward the front gap fg, the angle of the slope on the front gap side of the winding groove 1b is not 45 degrees. Further, the shape of the winding groove 1b on the front gap side may be an arc shape or a polygonal shape. Further, the depth of the winding groove 1b may be a depth that does not divide the magnetic layer 2,
If it is too deep, the magnetic path length increases and the magnetic flux transmission efficiency decreases. Therefore, in this embodiment, the winding groove 1b is formed to a depth of about 20 μm from the apex of the slope of the magnetic core groove 1a. The width of the winding groove 1b is determined by the width of the thin-film coil 4 and the number of windings to be formed in a later step, and in this embodiment, it is set to about 140 μm.

On the other hand, the separation groove 1c may have any shape as long as the magnetic layer 2 is divided, and has, for example, a rectangular shape that can be easily processed. The depth of the separation groove 1c needs to be such that the magnetic layer 2 is completely divided. In the present embodiment, the separation groove 1c extends from the bottom of the magnetic core groove 1a to a depth of about 150 μm.
c was formed. The width of the separation groove 1c is determined by the desired balance between the length of the front gap fg and the length of the back gap bg of the magnetic head. However, the length of the magnetic layer 2 on the front gap side is longer than the finally desired length of the front gap fg because the medium sliding surface is lapped when the magnetic head is finally processed into a predetermined shape. And the separation groove 1c is formed. Therefore, in this example, the separation groove 1c is formed so that the length of the magnetic layer 2 on the front gap side is about 300 μm and the length of the magnetic layer 2 on the back gap side is about 85 μm.

Since the winding groove 1b and the separation groove 1c thus formed are formed by a grinding wheel or the like, for example, as shown in an enlarged view of the separation groove 1c portion, the processed surface is in a rough state. Has become. If such roughness exists, bubbles tend to be generated in the glass when the glass 3 is filled in the subsequent step, so that the processed surfaces of the winding groove 1b and the separation groove 1c can be smoothed. preferable. However, the substrate 1 on which the winding groove 1b and the separation groove 1c are formed is
Since it has a complicated shape, it is very difficult to smooth the processed surface of the winding groove 1b and the separation groove 1c by a normal mirror surface treatment.

Therefore, in this embodiment, as shown in FIG. 8, a nonmagnetic thin film 2a is formed so as to cover the substrate 1 and the magnetic layer 2 on which the winding groove 1b and the separation groove 1c are formed. By thus forming the non-magnetic thin film 2a on the substrate 1 and the magnetic layer 2, for example, the separation groove 1c is enlarged.
As shown in, the surfaces of the substrate 1 and the magnetic layer 2 are smoothed.

Here, as the material of the non-magnetic thin film 2a,
For example, alumina (Al ₂ O ₃ ), SiO ₂ , Ti, etc. may be mentioned, but alumina is most suitable in consideration of the effect of suppressing the generation of gas and the compatibility with the glass to be filled in the subsequent step. Further, sputtering is suitable as a method for forming the non-magnetic thin film 2a, but vapor deposition or molecular beam epitaxy (MB
A physical film forming method (PVD) other than sputtering such as E) or a chemical film forming method (CVD) may be used. The thickness of the non-magnetic thin film 2a is not particularly limited, but it is desirable to uniformly cover the surfaces of the substrate 1 and the magnetic layer 2 including the processed surfaces of the winding groove 1b and the separation groove 1c. A thickness of about 0.5 μm is suitable.

Next, as shown in FIG. 10, the magnetic core groove 1
a, the winding groove 1b, and the separation groove 1c are melt-filled with the glass 3 having a low melting point. At this time, the nonmagnetic thin film 2a is formed on the substrate 1 and the magnetic layer 2, and the surface thereof is flat. Therefore, bubbles are hardly generated on the glass 3.

Moreover, since the surfaces of the substrate 1 and the magnetic layer 2 are covered with the non-magnetic thin film 2a, even if an inert gas or the like is taken into the magnetic layer 2 formed by sputtering or the like, the magnetic layer 2 is formed. The inert gas and the like taken into the glass 3 does not float up in the glass 3 when filling the glass 3. Therefore, in this example, the generation of bubbles due to the inert gas or the like taken into the magnetic layer 2 is suppressed.

Further, since the surfaces of the substrate 1 and the magnetic layer 2 are covered with the non-magnetic thin film 2a, various solvents such as a grinding liquid used for forming the groove and the substrate are fixed for forming the groove. Even if the wax or the like used for this purpose adheres to the substrate 1 or the magnetic layer 2, these various solvents or waxes do not vaporize and float up in the glass 3. Therefore, in the present embodiment, generation of bubbles due to various solvents and waxes attached to the substrate 1 and the magnetic layer 2 is suppressed.

Furthermore, since the substrate 1 and the magnetic layer 2 are covered with the non-magnetic thin film 2a, the magnetic layer 2 is hard to peel off from the substrate 1. Therefore, the magnetic layer 2 does not peel off from the substrate 1 when the thin film coil 4 is formed in a later step, or when a predetermined shape is ground for each magnetic core, and the magnetic layer 2 is peeled off. This prevents defects due to

Next, the surface of the glass 3 is mirror-finished to be smoothed, and as shown in FIG. 11, a thin film is formed on the glass 3 so as to pass through the winding groove 1b by a thin film forming process. The coil 4 is formed. At this time, as described above, the nonmagnetic thin film 2a covering the substrate 1 and the magnetic layer 2 prevents the magnetic layer 2 from peeling off from the substrate 1.

Next, as shown in FIG. 12, the magnetic head half blocks 11a and 11 are cut by cutting one row for each magnetic core.
b is produced, and the pair of magnetic head half blocks 11a and 11b produced in this way are joined by gold joining so that the magnetic layers 2 are butted. However, the magnetic head half blocks 11a and 11b may be joined by a chemical joining method using an adhesive or the like.

Finally, the magnetic cores are cut one by one and ground into a predetermined shape to join the pair of magnetic head halves 10a and 10b as shown in FIG. A magnetic head is manufactured. At this time, as described above, the peeling of the magnetic layer 2 due to the grinding process is prevented by the nonmagnetic thin film 2a covering the substrate 1 and the magnetic layer 2.

In the above embodiment, the thin film coil is formed on both of the pair of magnetic head halves, but the thin film coil may be formed on only one of the magnetic head halves.

Further, in the above-mentioned embodiment, the magnetic head half block is prepared by cutting the substrate on which the magnetic layer, the thin film coil and the like are formed one by one for each magnetic core. After joining, the magnetic cores were cut one by one, but the magnetic layer, the thin-film coil, and other substrates were previously cut one by one for each magnetic core to create a magnetic head half. The magnetic head halves may be bonded to each other, or the substrates on which the magnetic layers and the thin-film coils are formed may be bonded as they are, and the magnetic cores may be cut one by one afterwards.

[0043]

As is apparent from the above description, according to the present invention, since the non-magnetic thin film is formed on the substrate and the magnetic layer after the winding groove and the separation groove are formed, these grooves are not formed. The processed surface is smoothed. Therefore, the generation of bubbles generated when filling these grooves with glass is suppressed.

Further, due to the non-magnetic thin film formed on the substrate and the magnetic layer, the inert gas or the like taken in the magnetic layer is floated out into the glass or various solvents attached to the substrate or the magnetic layer are removed. Since the wax and the like are prevented from vaporizing and floating out in the glass, the generation of bubbles when filling the glass is suppressed.

As described above, according to the present invention, the generation of bubbles generated when the glass is filled is suppressed, so that a short circuit or disconnection hardly occurs during the formation of the thin film coil, and the yield of the magnetic head is greatly improved. Moreover, bubbles generated when the glass is filled are suppressed, so that the sliding surface of the magnetic head becomes smooth and its durability is improved.

Further, in the present invention, since the substrate and the magnetic layer are covered with the non-magnetic thin film, the magnetic layer is less likely to be peeled off from the substrate, and the magnetic layer is peeled off from the substrate in the process of manufacturing the magnetic head. Without losing
Defects due to peeling of the magnetic layer are also prevented, and the yield is improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration example of a magnetic head manufactured by applying the present invention.

FIG. 2 is an enlarged perspective view of an essential part showing an enlarged vicinity of a magnetic gap of the magnetic head shown in FIG.

FIG. 3 is a perspective view showing an example of a substrate.

FIG. 4 is a perspective view showing an example of a state in which a magnetic core groove is formed on a substrate.

FIG. 5 is a perspective view showing an example of a state in which a magnetic layer is formed on a substrate.

FIG. 6 is a perspective view showing an example of a state where winding grooves and separation grooves are formed on a substrate and a magnetic layer.

FIG. 7 is an enlarged perspective view of an essential part schematically showing a state of a processed surface of a separation groove formed by a grinding wheel.

FIG. 8 is a perspective view showing an example of a state in which a nonmagnetic thin film is formed on a substrate and a magnetic layer.

FIG. 9 is an enlarged perspective view of an essential part schematically showing a state of a processed surface of a separation groove after a nonmagnetic thin film is formed on a substrate and a magnetic layer.

FIG. 10 is a perspective view showing an example of a state where glass is filled in the magnetic core groove, the winding groove, and the separation groove.

FIG. 11 is a perspective view showing an example of a state in which a thin film coil is formed.

FIG. 12 is a perspective view showing an example of a state in which a pair of magnetic head half blocks are joined.

FIG. 13 is a diagram showing a ratio of causes of defects in a conventional magnetic head.

[Explanation of symbols]

 1 Substrate 1a Magnetic Core Groove 1b Winding Groove 1c Separation Groove 2 Magnetic Layer 2a Non-Magnetic Thin Film 3 Glass 4 Thin Film Coil 10a, 10b Magnetic Head Half 11a, 11b Magnetic Head Half Block g Magnetic Gap fg Front Gap bg Back Gap

Claims (6)

[Claims] 1. A magnetic head formed by joining a pair of magnetic head halves, wherein the magnetic head halves are made of a non-magnetic substrate, and a magnetic layer is formed on the substrate to form a magnetic core. A magnetic head comprising a non-magnetic thin film formed on the substrate and the magnetic layer, glass filled on the non-magnetic thin film, and a thin-film coil formed on the glass portion. 2. The magnetic head according to claim 1, wherein the non-magnetic thin film is made of alumina. 3. The magnetic head according to claim 1, wherein the magnetic layer is formed by laminating a plurality of metal magnetic films with an insulating film interposed therebetween. 4. A method of manufacturing a magnetic head comprising a pair of magnetic head halves joined together, wherein a magnetic core groove is formed by cutting a magnetic core groove on a substrate made of a non-magnetic material to form a magnetic core forming surface. A magnetic layer to be a magnetic core is formed on a substrate on which a core groove is formed, and a winding groove for arranging a thin-film coil and a magnetic layer are provided for each magnetic core on the substrate on which the magnetic layer is formed. A separation groove for separation is formed, a non-magnetic thin film is formed on the substrate and the magnetic layer on which the winding groove and the separation groove are formed, and glass is formed on the magnetic core groove, the winding groove, and the separation groove. A method of manufacturing a magnetic head, which comprises filling and forming a thin film coil in the glass portion so as to pass through a winding groove to produce a magnetic head half. 5. The method of manufacturing a magnetic head according to claim 4, wherein the non-magnetic thin film is made of alumina. 6. The magnetic layer is formed by laminating a plurality of metal magnetic films with an insulating film interposed therebetween.
Alternatively, the method of manufacturing the magnetic head according to the above item 5.