JPH09219009A - Magnetic head and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic head having high gap accuracy and high joint strength. SOLUTION: The thicknesses at the time of forming glass layer materials are specified to >=2.5% of a desired gap length A or >=10nm at the time of joining the two magnetic cores 1a, 1b obtd. by forming ground surface films 2a, 2b consisting of silica or alumina on the one surface of respective magnetic cores and further forming the glass layer materials on these ground surface layers 2a, 2b by diffusion of the glass layer materials at the time of joining the two magnetic cores via the gap material. The glass layer materials softened or fused at the time of joining the cores by softening or melting are partly extruded from joint surfaces, by which the thickness of the glass layers 3 in the gap material is made smaller than the total of the thicknesses at the time of forming the glass layer materials.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head and its manufacturing method. More specifically, the present invention relates to a magnetic head that can be preferably used in a magnetic recording / reproducing apparatus such as a VTR (video tape recorder), an FDD (floppy disk drive), and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as a method of manufacturing a magnetic head, for example, a layer having a bonding force is provided on the surface of a magnetic core, and two such magnetic cores are bonded through the layer to reduce the number of steps. In addition, there is a method for producing an inexpensive magnetic head having a desired gap length accuracy, which is described in, for example, Japanese Patent Publication No. 2-58684.

FIG. 5 is a schematic view for explaining the side surface of the magnetic head described in the above publication. In FIG. 5, 8 is a magnetic core made of a magnetizable material such as ferrite, 9 is a non-magnetizable metal, metal oxide, boride, nitride,
A layer made of at least one selected from the group consisting of silicon oxide and ferrite that is non-magnetizable at ambient temperature (hereinafter, also referred to as "underlayer"), 10 is 95 to 100% by weight.
Of the above glass and a mixture of 0 to 5% by weight of other components (hereinafter, also referred to as “glass layer”).
l ₂ O ₃ 16% by weight, B ₂ O ₃ 44% by weight, BaO
Non-magnetizable material glass consisting of 40% by weight, 11 is a back gap material, but the layer structure of the gap material is not described in detail.

As a conventional magnetic head, the magnetic head as shown in FIG. 5 has the underlayer 9 formed by sputtering on the surface of the magnetic core 8 on which the gap material is provided. A glass layer material is deposited on at least one of the underlayers of the magnetic cores (that is, they become a glass layer after bonding), and these two magnetic cores are contacted with each other, and the glass layer is heated in a heating furnace. It is obtained by heating to a temperature sufficient to soften the material, welding and joining.

Thus, the conventional magnetic head manufacturing method is as follows.
By using the glass of the specific composition as the gap material, there is no difference in the composition between the glass target material and the glass layer even by sputtering, and the viscosity of the glass layer material in the heating furnace changes every time it is manufactured. The purpose is to be constant. Further, in the bonding method, by providing the underlayer as an intermediate layer between the glass layer and the magnetic core (ferrite), it is possible to prevent the glass from eroding the ferrite 8 by sputtering, and the gap length is reduced. I'm trying to prevent it from growing.

However, in the above manufacturing method, the amount of deformation of the softened glass layer must be controlled by always maintaining the surface pressure constant during the welding and joining, and the gap length is controlled. There is a problem that it is difficult.

Even if an underlayer is provided as the intermediate layer, the glass layer material as well as the underlayer is softened at the time of the welding and joining due to the diffusion of the glass layer material into the underlayer. There is a problem that it is difficult to increase the long precision.

Further, if the thickness of the glass layer material is too thin, the bonding strength is lowered and, for example, breakage occurs in the manufacturing process of the magnetic head.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic head having a high gap length accuracy and a high bonding strength, and a method for manufacturing the same.

[0010]

DISCLOSURE OF THE INVENTION The present invention comprises two magnetic cores and a gap material provided between the two magnetic cores, and the two gap layers made of silica or alumina. A magnetic head comprising a glass layer provided between the two magnetic cores, the two magnetic cores provided with the underlayer being bonded by diffusion of the glass layer material, and having a thickness of the two underlayers. The present invention relates to a magnetic head having a total thickness greater than the thickness of a glass layer and a glass layer and an underlayer being substantially separated.

The present invention is also a manufacturing method for obtaining the above-mentioned magnetic head, wherein the thickness when forming the glass layer material on the underlayer is 2.5 to 10% of the desired gap length. The present invention relates to a characteristic magnetic head manufacturing method.

The present invention is also a method for manufacturing the above magnetic head, wherein the ratio of the thickness of the underlayer to the thickness when the glass layer material is deposited on the underlayer is 2.7 or more. Relates to a method of manufacturing a magnetic head.

Further, in the present invention, in the above-mentioned manufacturing method, it is preferable that the surface pressure when the glass layer material is softened or melted and bonded is set to 1.3 to 2.2 kgf / cm ² .

Further, the present invention is a method of manufacturing a magnetic head in which two magnetic cores are joined via a gap material, wherein an underlayer made of silica or alumina is formed on one surface of each magnetic core, and each of them is further formed. After depositing a glass layer material on the underlayer of the above, when joining these two magnetic cores by diffusion of the glass layer material, the thickness when depositing the glass layer material is set to a desired gap length of 2.5.
% Or 10 nm or more and when the glass layer material in the gap material is formed into a film by extruding a part of the glass layer material softened when welding and joining the glass layer material. The present invention relates to a method of manufacturing a magnetic head, which is characterized in that it is smaller than the total thickness of

The present invention also provides the above magnetic head,
Between the underlayer and the glass layer, Cr, Al, Cu, Ti,
It is preferable to provide a non-magnetic intermediate layer made of at least one selected from the group consisting of Au, Pt, SiN and TiN.

In the present invention, it is preferable that the nonmagnetic intermediate layer is formed by oxidizing Cr and Cu while forming a film in an inert gas atmosphere containing oxygen.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In the magnetic head of the present invention, the gap material is formed in a three-layer structure of underlayer / glass layer / underlayer, and the total thickness of the two underlayers is less than the thickness of the glass layer. The largest feature is that these underlayer and glass layer are substantially separated.

In the present specification, the diffusion of the glass layer material means, for example, when the glass layer material is formed on each underlayer and then the films are brought into contact with each other and heated, the glass layer material is softened or melted. However, the glass components existing in the vicinity of the bonding surface are mixed together. Further, the erosion by the glass layer material includes that the glass component reaches the ferrite material due to such diffusion, and as a result, the magnetic characteristics of the ferrite material are deteriorated.
As a specific means for the diffusion, for example, welding can be cited. The term “substantially separate the glass layer and the underlayer” means, for example, a portion rich in the glass layer material and a portion rich in the material forming the underlayer, and the interface between these two layers is not always clear. Of course, this includes mixing these two materials near the interface.

FIG. 1 is a schematic cross-sectional view for explaining a gap portion of a magnetic head obtained in an embodiment of the present invention. In FIG. 1, 1a and 1b are magnetic cores made of ferrite, 2a and 2b are base layers, and 3 is a glass layer.

As shown in FIG. 1, the magnetic head of the present invention has a magnetic core 1a having an underlayer 2a formed on one magnetic core 1a, and a magnetic layer 1b having another underlayer 2b with a glass layer 3 interposed therebetween. It has a structure that is joined with.

The underlayer 2a or 2b is formed by depositing a glass layer material on the underlayer 2a or 2b before bonding or both of them, so that the magnetic core 1a is formed by the glass layer material.
Alternatively, it is possible to prevent 1b from being eroded, which makes it easy to increase the accuracy of the gap length (that is, the length indicated by A in FIG. 1) after joining.

Since the glass layer 3 is provided for joining the two magnetic cores and is separated from the underlayers 2a and 2b, it is easy to improve the accuracy of the gap length, and the joining is facilitated. Great strength.

The gap composed of these underlayers 2a and 2b and the glass layer 3 has non-magnetization property, and as shown in FIG. 1, it is protruded from the gap by sliding a tape for VTR, for example. The magnetic flux can record information on the tape, and conversely, the magnetic flux from the tape can be captured by the gap to reproduce the information on the tape.

The gap length varies depending on the model of the magnetic recording / reproducing apparatus, but is, for example, 370-43.
0 nm can be mentioned. The glass layer has a thickness of 10 to 10 when the gap length is 380 to 420 nm.
The thickness of the underlayer is preferably 40 nm, and the thickness of each of the underlayers is preferably 100 to 210 nm.

Examples of the glass layer material include Pb
O, SiO ₂ , ZnO, Na ₂ O, K ₂ O, BaO, B ₂ O
Examples of the glass include ₃ , Al ₂ O ₃ , ZrO _{2 and} glasses made of two or more of these. It is preferable that the gap length accuracy is high, the bonding strength is high, and the reliability is excellent.

The softening point of the glass layer material is 300 to 7
It is preferably 50 ° C. Further, as the glass layer material, for example, PbO 56.7% (weight%, the same applies hereinafter), SiO ₂ , 33.6%, ZnO 4.5%, Na ₂ O
455 of glass consisting of 4.2% and K ₂ O 1.0%
The viscosity at 0 ° C. is preferably 10 ¹¹ to 10 ¹² poise.

As a material for forming the underlayer, silica has a high bonding strength with the magnetic core, is free from erosion by the glass, has a high gap length accuracy, and is a highly reliable magnetic head. Alternatively, alumina is preferable, and alumina is more preferable.

The silica is preferably ordinary silica.

As the alumina, ordinary ones are preferable.

As a material for forming the magnetic core, a commonly used material such as ferrite, a metal magnetic material having a high saturation magnetic flux density and a high initial magnetic permeability is preferable.

Further, in the magnetic head of the present invention, since there is no diffusion of the glass layer material into the underlayer between the glass layer and the underlayer, the accuracy of the gap length is improved, so that Cr, Al, Cu, Ti, Au, Pt, SiN, T
It is preferable that iN or a nonmagnetic intermediate layer composed of two or more of these is provided, and among these, Cr,
Cu, SiN, TiN or two or more of these are more preferable.

Further, since the non-magnetic intermediate layer obtained by using Cr or Cu is oxidized, the wettability by the glass layer material is improved, and the magnetic head having more excellent bonding strength can be obtained.

The thickness of the non-magnetic intermediate layer may be such that the diffusion can be prevented, but is, for example, 5 to 30.
It is preferably about nm.

Next, a method of manufacturing the magnetic head of the present invention will be described.

First, a block made of ferrite, for example, is processed into a predetermined size and shape to obtain two magnetic core blocks.

Next, an underlayer is formed on one surface of each core by, for example, sputtering or vapor deposition.

Next, a glass layer material is deposited on the surface of each underlayer by, for example, sputtering or vapor deposition to obtain two magnetic cores.

These two magnetic core blocks were superposed so that the films of the glass layer material were in contact with each other, and then 30 at a temperature of 400 to 700 ° C. in a heating furnace.
The magnetic head of the present invention is obtained by softening or melting the glass to bond it to form a glass layer for ˜180 minutes, and then slicing the block to an appropriate thickness.

The underlayer and glass layer materials used in this manufacturing method are preferably those listed above as the underlayer and glass layer materials.

In the above-mentioned manufacturing method, the thickness when the glass layer material is formed is 2.5 to 10 times the gap length.
%, Preferably by setting the thickness to be in the range of 2.5 to 5%, the softening region when softening or melting the glass layer material is reduced and the gap length accuracy is further improved. It becomes easy to increase the height, and the joint strength can be increased.

In the above manufacturing method, the glass layer material is set by setting the ratio of the thickness of the underlayer to the thickness when the glass layer material is deposited to 2.7 or more, preferably 15 to 20. A region to be softened or melted when softening or melting is joined is limited, and it becomes easier to increase the accuracy of the gap length, and the joining strength can be increased.

Further, in the above-mentioned manufacturing method, the surface pressure at the time of welding the glass layer material is set to 1.3 to 2.2 kgf / cm ² , preferably 1.5 to 2.0 kgf / mm ² , so that the joining surface is A sufficient contact area can be obtained, sufficient bonding strength can be secured without chip cracking, and the gap length accuracy can be improved.

In the above manufacturing method, the thickness of the glass layer material formed is 2.5% of the gap length.
Or more, preferably 2.5 to 5%, or when the glass layer material is formed into a film having a thickness of 10 nm or more,
The gap material is preferably set to 10 to 50 nm, and when the glass layer material is softened or melted to be joined, a part of the softened or melted glass layer material is extruded from the joining surface. By setting the thickness of the glass layer to be formed to be less than the sum of the film thicknesses of the glass layer materials of the two magnetic cores before joining, when softening or melting the glass layer material and joining Excessive softened or melted glass layer material is extruded from the joint surface, and the gap length is determined only by the thickness of the underlayer, so that the gap length accuracy is increased.

In the above manufacturing method, Cr, Al, Cu, Ti, Au, P are provided between the underlayer and the glass layer material film.
t, SiN, TiN or two or more thereof, preferably Cr, Cu, SiN, TiN or a non-magnetic intermediate layer consisting of two or more thereof is formed by, for example, sputtering or vapor deposition, whereby the glass layer material is As in the case of forming a film on the underlayer, it is possible to prevent diffusion into the underlayer, and when the glass layer material is softened or melted and bonded, the softened or melted region forms the glass layer. Since it is limited only to the thickness at that time, the gap length accuracy can be increased.

Further, in the above-mentioned manufacturing method, the glass layer material is formed by forming a nonmagnetic intermediate layer by oxidizing Cr or Cu, preferably Cr while forming a film in an inert gas atmosphere containing oxygen. At this time, the wettability of the glass is improved and the bonding strength is increased. The oxygen concentration at this time is preferably 5 to 20% by volume, and the inert gas is preferably, for example, argon or nitrogen. Also,
In this manufacturing method, after the Cr or Cu film is formed, annealing can be performed in an inert gas atmosphere containing oxygen at the above concentration. The annealing temperature at this time is preferably about 300 to 700 ° C., and nitrogen is preferable as the inert gas. The non-magnetic intermediate layer is not shown in FIG.

In the magnetic head obtained by the above manufacturing method, the total thickness of the two underlayers is larger than the thickness of the glass layer, and the glass layer and the underlayer are substantially separated from each other. The long accuracy is the target value ± 15 nm, the bonding strength is 60 to 70 gf, and the normally required gap length accuracy (target value ± 30 nm) and the bonding strength (5
0 gf)) can be sufficiently satisfied.

As the conditions in the method of manufacturing the magnetic head of the present invention, for example, the following combinations are preferable.

(A) Thickness of base layer made of silica or alumina 100 to 180 nm (B) Thickness when forming glass layer material 10 to 40 nm (C) Cr, Al, Cu, Ti, Au, Pt , SiN and TiN, non-magnetic intermediate layer consisting of at least one selected from the group consisting of SiN and TiN (D) Surface pressure during welding 1.3 to 2.2 kgf / cm ² (E) Glass layer material during welding Temperature 550-750 ° C

This condition is advantageous in that the gap length accuracy and the bonding strength can be easily controlled, and the obtained magnetic head has a high gap length accuracy and a large bonding strength.

More preferably, the thickness of the underlayer made of (A1) alumina is 100 to 150 nm. (B1) PbO, SiO ₂ , ZnO, Na ₂ O, K ₂ O, BaO, B ₂ O ₃ , Al ₂ O ₃ , ZrO ₂ or _two or more kinds of these glass layer materials when formed into a film thickness of 10 to 20 nm (C1) Cr non-magnetic intermediate layer (D1) surface pressure at the time of welding 1.5 to 2. 0 kgf / cm ² (E) Temperature of glass layer material during welding 650 to 700 ° C.

This condition is excellent in that it is easy to control the gap length accuracy and the bonding strength, and the obtained magnetic head has a higher gap length accuracy and a larger bonding strength.

[0052]

EXAMPLES Next, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

FIG. 1 is a schematic cross-sectional view for explaining a gap portion of a magnetic head obtained in the following examples, showing a basic structure.

[Example 1] 2.0 cm x 0.2 cm x
Magnetic core 1a made of ferrite with a size of 0.1 cm
One surface (2.0 cm x 0.2 cm) of the underlayer 2 having a thickness of 140 nm containing silica as a main component by sputtering.
a was formed.

Next, a glass layer material having the following composition (not shown in the figure, but to be the glass layer 3 after bonding, which will be described later) is further formed on the underlayer 2a by sputtering.

(Composition of glass layer material) PbO 56.7% SiO ₂ 33.6% ZnO 4.5% Na ₂ O 4.2% K ₂ O 1.0%

On the other hand, one surface (2.0 cm × 0.2 cm) of the magnetic core 1b having the same size as the magnetic core 1a.
Then, the base layer 2b was formed in the same manner as described above, and the glass layer material was further deposited.

Next, these two magnetic cores were superposed so that the glass layer materials were in contact with each other, and they were placed in a heating furnace for 7 hours.
Surface pressure during welding at 00 ° C for 1 hour is 1.6 kgf / cm ²
Then, the glass layer 3 having a thickness of 10 nm was formed under the conditions described above to obtain the magnetic head of the present invention.

In the present embodiment, magnetic heads having a thickness of 20 nm and a thickness of 40 nm when forming the glass layer were also obtained by changing the thickness when forming the glass layer material.

The following measurements were performed on these magnetic heads.

Effective gap length: When the gap length is an integral multiple of the recording wavelength, no magnetic flux flows in the head core, so at the frequency f (= v / λ: v is the relative speed between the head and the medium) corresponding to the recording wavelength λ. The reproduction output becomes 0. FIG. 3 is a graph showing the relationship between the frequency and the reproduction output of the magnetic head obtained in Examples 1 to 5 of the present invention. In FIG. 3, G1 indicates the gap length of the magnetic head.
Therefore, the frequency at which the reproduction output has a minimum value was measured, the wavelength at this time was calculated from the value by the following equation, and this was taken as the effective gap length. λ = v / f

Thickness of formed glass layer: Measured using a stylus type film thickness meter.

Thickness of glass layer in magnetic head: SEM
It was measured using a (scanning electron microscope).

Bonding strength: It is very important to secure the strength of a chip that has been subjected to gap bonding. Ultimately, it is required that the gap does not break or open. FIG. 4 is a diagram for explaining a method of measuring the bonding strength of the magnetic heads obtained in Examples 1 to 5 of the present invention. In FIG. 4, 4 is a base, 5 is a tip, 6 is a point of action when pushing the tip of the tip with a needle with a load cell,
7 indicates a gap. As shown in Fig. 4, when the chip without the narrow track processing is rotated 90 ° on the base and pasted with the instant adhesive, the tip of the chip is pushed by the needle with the load cell, and the chip is cracked. Measure the load of. About 20 chips were measured for each bonding condition and an average value was obtained.

The results are shown in FIG. FIG. 2 is a graph showing the bonding strength when the thickness of the glass layer is changed.

As is clear from FIG. 2, when the thickness of the glass layer is 10 nm, sufficient bonding strength cannot be obtained. That is, when the thickness of the glass layer is less than 10 nm, the bonding is not sufficiently performed, and chip cracks occur due to insufficient bonding strength.

On the other hand, the thickness of the glass layer is 10 nm, 20 n
The effective gap length at m and 40 nm is 0.43 to
The ratio of the number of magnetic heads within the range of 0.47 μm (the number of magnetic heads used for measurement) is 38, respectively.
%, 100%, and 0%, and if the glass layer is thicker than necessary, the region that softens during welding increases and the gap length varies.

As is clear from these results, when the thickness of the glass layer is 20 nm, a magnetic head having the most stable gap length and sufficient bonding strength can be obtained.

[Embodiment 2] In Embodiment 1, the thickness of the underlayer is set to 95 nm or 125 nm, and the thickness of the glass layer is set to 35 nm (thickness 35 when the glass layer material is formed).
nm) was obtained in the same manner as in Example 1 except that the effective gap length was measured.

The ratio of the number of magnetic heads having the effective gap length within the range of 0.38 to 0.42 μm (same as above) when the thickness of the underlayer is 95 nm is 18%. When the thickness is 125 nm, the effective gap length is 0.
The ratio of the number of magnetic heads within the range of 44 to 0.48 μm (as described above) was 55%.

As is apparent from the above, when the ratio of the thickness of the underlayer to the thickness when the glass layer material is formed is small, the glass layer material easily diffuses in the entire gap material,
Moreover, since the weight ratio of the glass layer material in the gap material is high, the viscosity of the entire gap material is lowered, which leads to variations in the effective gap length. That is, the gap length can be easily controlled by making the thickness of the glass layer material thin and increasing the thickness of the underlayer within the range where the bonding strength can be secured.

[Third Embodiment] In the first embodiment, the thickness of the underlayer is 125 nm and the thickness of the glass layer is 35 nm (thickness of 35 nm when the glass layer material is formed), and the thickness of the glass layer at the time of welding is set. Surface pressure of 1.3, 1.6 and 2.2 kgf
/ Cm ² and then, except that the in the same manner to give a magnetic head of the present invention, was measured effective gap length in the same manner as in Example 1.

The surface pressure during welding is 1.3, 1.6 and 2.
The effective gap length at ² kgf / cm ² is 0.44 ~
The ratio of the number of magnetic heads within the range of 0.48 μm (as described above) is 27%, 55% and 50%, respectively.
%Met.

As is apparent from the above, when the surface pressure during welding is low, sufficient contact cannot be obtained at the joint surface, and variations in the effective gap length occur. Further, if the surface pressure at the time of welding is too high, ferrite and the gap material adhered before the welding will have microcracks, and chip cracks will occur, so that sufficient bonding strength cannot be obtained. That is, by setting the surface pressure during welding to 1.3 to 2.2 kgf / cm ² , a stable effective gap length and strong joining can be obtained.

[Embodiment 4] In Embodiment 1, the thickness of the underlayer is 120 nm and the thickness of the glass layer is 30 nm (thickness when forming the glass layer material is 30 nm). An effective gap length was measured in the same manner as in Example 1 except that silica or alumina was used as the material for forming the magnetic head of the present invention.

When the material forming the underlayer is silica or alumina, the ratio of the number of magnetic heads having the effective gap length within the range of 0.39 to 0.43 μm (as described above) is:
It was 69% and 90%, respectively.

As is clear from this, the variation of the effective gap length is reduced by changing the material forming the underlayer from silica to alumina. This is because alumina is less likely to be diffused by the glass layer material than silica, the region that softens during welding is reduced, and a stable effective gap length is obtained. Further, by providing a non-magnetic intermediate layer between the glass layer material film and the underlayer to prevent the diffusion of Cr and the like, the diffusion of the glass layer material into the underlayer is further suppressed, and a stable effective gap is obtained. You can get long. In addition, by oxidizing the film forming step such as Cr forming the non-magnetic intermediate layer,
The wettability with the glass layer material is improved, the adhesion of the glass layer is increased, and a strong bond is obtained.

[Embodiment 5] In Embodiment 4, the thickness of the glass layer is set to 20 nm (the thickness when forming the glass layer material is 20 nm), and alumina is used as the material for forming the underlayer to reduce the thickness. The thickness is set to 170 nm, and after forming the underlayer, Cr is formed by vapor deposition in an argon gas atmosphere containing 10% by volume of oxygen, and a thickness of 10 nm made of chromium oxide is formed.
A magnetic head of the present invention was obtained in the same manner except that the glass layer material was deposited after forming the non-magnetic intermediate layer.

As shown in Example 4, when alumina is used as the material for forming the underlayer, diffusion from the glass layer material is suppressed, and a nonmagnetic intermediate layer made of chromium oxide is inserted to make the alumina underlayer from the glass. The heat diffusion to Further, the surface pressure during welding is increased within a range where microcracks do not enter the ferrite and the gap material, and the welding temperature is set to a temperature at which the viscosity of the glass layer material is sufficiently lowered. As a result, only the formed glass layer material is softened, and the surplus glass layer material is extruded out of the joint surface, and the gap material is the underlayer made of alumina,
It is composed of a non-magnetic intermediate layer made of chromium oxide and an extremely thin glass layer material having almost no thickness, and the gap length is determined by the thickness of the underlayer made of alumina and the thickness of the non-magnetic intermediate layer made of chromium oxide. Therefore, a stable gap length can be obtained and a strong joint can be realized.

[0080]

As is clear from the above results, in the magnetic head of the present invention, in the gap material, the total thickness of the two underlayers is larger than the thickness of the glass layer, and the underlayer and the glass layer are separated. Therefore, the gap length accuracy is high,
Further, the magnetic head has a high bonding strength.

Further, according to the manufacturing method of the present invention, the thickness when the glass layer material is deposited to a desired gap length is 2.5 to.
Since it is set to 10%, the region that softens with respect to the entire gap material is limited, so that there is an effect that a magnetic head with high gap length accuracy and high bonding strength can be obtained.

Further, in the manufacturing method of the present invention, the ratio of the thickness of the underlayer to the thickness at which the glass layer material is deposited is set to 2.7 or more, and a proper bonding temperature is selected to achieve sufficient bonding. Even if the strength is secured, it is possible to obtain an underlayer that is not diffused from the glass, and it is possible to obtain an accurate gap length.

Further, according to the manufacturing method of the present invention, the surface pressure when the glass layer material is softened or melted and bonded is 1.3 to 2.
By setting the pressure to ² kgf / cm ^2, it is possible to secure the contact area of the joint surface without causing chip cracking, and there is an effect that a sufficiently strong joint can be obtained.

Further, in the production method of the present invention, by selecting an appropriate welding temperature, only the glass is softened at the time of welding, and the surplus softened at the time of welding is selected by appropriately selecting the surface pressure at the time of joining. Since the glass layer material of is extruded from the bonding surface and the gap material after welding is composed of the underlayer and the ultrathin glass layer, the gap length is uniquely determined only by the thickness of the underlayer. The effect is that a good and stable magnetic head can be obtained.

Further, in the magnetic head of the present invention, since the non-magnetic intermediate layer is provided between the underlayer and the glass layer,
Since the diffusion of the glass layer material to the underlayer is completely blocked and the softening region during welding is determined only by the thickness when forming the glass layer material, the gap length accuracy is high and the bonding strength is high. It is a magnetic head.

Further, in the manufacturing method of the present invention, the wettability of the glass layer material is improved by oxidizing the non-magnetic intermediate layer from its formation stage, and the adhesion between the glass layer and the non-magnetic intermediate layer is strengthened. Therefore, there is an effect that a magnetic head having high bonding strength can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view for explaining a gap portion of a magnetic head obtained in Examples 1 to 5 of the present invention.

FIG. 2 is a graph showing the bonding strength when the thickness of the glass layer in the gap of the magnetic head obtained in Example 1 of the present invention is changed.

FIG. 3 is a graph showing the relationship between the frequency and the reproduction output of the magnetic head obtained in Examples 1 to 5 of the present invention.

FIG. 4 is a diagram for explaining a method for measuring the bonding strength of the magnetic heads obtained in Examples 1 to 5 of the present invention.

FIG. 5 is a schematic diagram for explaining a side surface of a magnetic head obtained by performing conventional gap bonding.

[Explanation of symbols]

A gap length, 1a, 1b ferrite magnetic core, 2a, 2b underlayer, 3 glass layer, 4 base, 5 chips, 6 working point, 7 gap, 8 magnetic core, 9 underlayer, 10 glass layer, 11 back Gap material

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hiroki Nakajima 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Sanryo Electric Co., Ltd.

Claims (7)

[Claims] 1. A glass layer provided between two magnetic cores and a gap material provided between the two magnetic cores, wherein the gap material is made of silica or alumina, and a glass layer provided between the two underlayers. And a magnetic head in which two magnetic cores provided with the underlayer are joined by diffusion of a glass layer material, and the total thickness of the two underlayers is greater than the thickness of the glass layer. A magnetic head having a large size in which a glass layer and an underlayer are substantially separated. 2. A manufacturing method for obtaining the magnetic head according to claim 1, wherein the thickness when forming the glass layer material on the underlayer is 2.5 to 10% of the desired gap length. A method of manufacturing a magnetic head characterized by. 3. A method for producing the magnetic head according to claim 1, wherein the ratio of the thickness of the underlayer to the thickness when the glass layer material is formed on the underlayer is 2.7 or more. A method of manufacturing a magnetic head, which is characterized in that 4. The manufacturing method for obtaining the magnetic head according to claim 1 or the manufacturing method according to claim 2 or 3, wherein the surface pressure when the glass layer material is softened or melted and bonded is 1.3 to A method of manufacturing a magnetic head, characterized in that the magnetic head is 2.2 kgf / cm ² . 5. A method of manufacturing a magnetic head in which two magnetic cores are joined via a gap material, wherein an underlayer made of silica or alumina is formed on one surface of each magnetic core, and each underlayer is further formed. After depositing the glass layer material on the substrate, when joining these two magnetic cores by diffusion of the glass layer material, the thickness when depositing the glass layer material is 2.5% or more of the desired gap length or The thickness of the glass layer in the gap material when the glass layer material is formed by extruding a part of the glass layer material having a thickness of 10 nm or more and softened at the time of welding and joining from the joining surface. A method of manufacturing a magnetic head, which is smaller than the total of 6. A magnetic head according to claim 1 or a magnetic head obtained by the manufacturing method according to claim 2, wherein Cr, Al,
A magnetic head comprising a non-magnetic intermediate layer made of at least one selected from the group consisting of Cu, Ti, Au, Pt, SiN and TiN. 7. A manufacturing method for obtaining a magnetic head according to claim 6, wherein Cr or Cu is formed in an inert gas atmosphere containing oxygen while being oxidized to form a non-magnetic intermediate layer. A method of manufacturing a magnetic head characterized by.