JP2000105903A - Magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the abutting parts of a pair of magnetic core halves adhere closely to each other without a space by forming a magnetic gap with the end faces of a metallic magnetic thin film abutted on each other through a nonmagnetic film, and forming this nonmagnetic film over the total width on the sliding face of a magnetic recording medium. SOLUTION: With a pair of magnetic core halves joined through a nonmagnetic film 8, a metallic magnetic thin film 5 forms a magnetic core 9. In this case, the nonmagnetic film 8 serves a function of jointly incorporating the pair of magnetic core halves. On the sliding face 10, the nonmagnetic film 8 is formed over the total width of this sliding face 10 as well as the front gap 14; hence, the magnetic head is formed in the shape of a smooth circular arc, with the sliding face 10 having no difference in level. In addition, the magnetic head, having a large area with the nonmagnetic film 8 formed, is strong in the joining strength through the metallic diffusion welding of this nonmagnetic film 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head having a magnetic path formed by a metal magnetic thin film, and more particularly, to a magnetic head in which a pair of magnetic core halves are joined and integrated by metal diffusion bonding.

[0002]

2. Description of the Related Art A magnetic head is mounted on a magnetic recording / reproducing device such as a video tape recorder (VTR), and records and / or reproduces information signals on a magnetic recording medium (hereinafter referred to as recording / reproducing). Is what you do.

In a magnetic head, a metal magnetic thin film is formed on each magnetic gap forming surface of a pair of magnetic core halves made of single crystal ferrite or the like, and the pair of magnetic core halves are joined to the magnetic gap forming surfaces. A so-called metal-in-gap (MIG) type magnetic head, which is integrated by bonding together, and a so-called laminated type magnetic head in which a metal magnetic thin film is sandwiched between nonmagnetic ceramic substrates have been proposed and put into practical use.

[0004] In order to cope with higher density and digitization of a recording signal in the field of magnetic recording, a magnetic head that can exhibit good electromagnetic conversion characteristics in a higher frequency band is desired. Further, it is desired that a magnetic head for a VTR be miniaturized in order to cope with miniaturization and high performance of the apparatus by mounting a plurality of magnetic heads on a small drum.

The above-described MIG type magnetic head has a large impedance and is not suitable for use in a high frequency band. Also,
The stacked magnetic head requires a reduction in the thickness of the metal magnetic thin film forming the magnetic path with a decrease in the track width due to an increase in the density of the recording signal. There is a limit to miniaturization.

Therefore, as a magnetic head capable of exhibiting good electromagnetic conversion characteristics in a high frequency band, for example, as described in JP-A-6-259717, "Magnetic head and its manufacturing method". A so-called bulk thin-film magnetic head has been proposed in which the impedance is reduced by shortening the magnetic path of a magnetic core manufactured by a thin-film forming process.

In this bulk thin film type magnetic head, a pair of magnetic core halves each having a metal magnetic thin film formed as a magnetic core on a nonmagnetic substrate are joined and integrated with each other via the nonmagnetic film. A magnetic gap is formed between these metal magnetic thin films. In this bulk thin-film magnetic head, a coil-forming recess is formed on a joining surface of at least one of the pair of magnetic core halves, and a thin-film coil is formed in the coil-forming recess. .

In a bulk thin film type magnetic head, a nonmagnetic substrate such as glass is filled in a nonmagnetic substrate on which a metal magnetic thin film forming a magnetic core is formed obliquely, and a concave portion formed in the nonmagnetic material is formed. A pair of magnetic core halves is formed, for example, by forming a thin film coil. After a pair of magnetic core halves are subjected to a flattening process with respect to each other,
A non-magnetic film as a magnetic gap is formed. And
The pair of magnetic core halves constitute a bulk thin-film magnetic head by metal-diffusion bonding of a non-magnetic film formed on each abutting surface.

[0009]

However, in a conventional bulk thin-film magnetic head, when a flattening process is performed on the abutting surfaces of a pair of magnetic core halves, a non-magnetic material such as a filled glass is used. Because the material and the grinding rate of the joint between the thin-film coils are different, 100 nm
A level difference occurs.

For this reason, in the conventional bulk thin film magnetic head, the portions to be substantially joined in the joining step of the magnetic gap are only the joints between the end faces of the opposed metal magnetic thin films and the thin film coils. .

Therefore, in the conventional bulk thin film magnetic head, a nonmagnetic film as a magnetic gap is formed only at the end faces of the metal magnetic thin films facing each other and only at the junction between the thin film coils. The conventional bulk thin-film magnetic head uses a magnetic field corresponding to the back gap side of the magnetic core to compensate for the insufficient bonding strength of the pair of magnetic core halves due to the small area where the non-magnetic film is subjected to metal diffusion bonding. An adhesive or the like was applied to the periphery of the butted surface of the core halves to be joined and reinforced.

However, the conventional bulk thin-film magnetic head manufactured as described above has a structure as shown in FIG.
When the sliding surface of the magnetic recording medium is viewed, the magnetic gap, that is, the butting portion of the pair of magnetic core halves 102 and 103 where the nonmagnetic film 101 is formed,
In other words, the air gap 105 is provided at a position deviating from the position 4. Therefore, the conventional bulk thin film magnetic head is
When a magnetic recording medium is slid on a sliding surface to record and reproduce a recording signal, abrasion powder or the like of the magnetic recording medium is accumulated in the gap, and the abrasion powder or the like damages the magnetic recording medium. There was a problem.

The present invention has been made to solve the above-mentioned problem, and to provide a magnetic head which does not damage the magnetic recording medium when recording and reproducing a recording signal on the magnetic recording medium. Aim.

[0014]

In order to achieve the above-mentioned object, a magnetic head according to the present invention comprises a metal magnetic thin film formed obliquely on a substrate and a concave portion formed with a thin-film coil. The magnetic magnetic thin film includes a pair of magnetic core halves each having a flat butted surface made of a nonmagnetic material, and a magnetic gap formed by abutting the metal magnetic thin films so that the end surfaces thereof face each other via the nonmagnetic film. The non-magnetic film is formed over the entire width of the sliding surface of the magnetic recording medium.

In the magnetic head according to the present invention configured as described above, the butted portions of the pair of magnetic core halves are brought into close contact with each other on the sliding surface of the magnetic recording medium without forming a gap. Therefore, the magnetic head does not accumulate abrasion powder or the like of the magnetic recording medium in the butted portion of the pair of magnetic core halves, and when recording and reproducing a recording signal on the magnetic recording medium, No damage to the media.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. Hereinafter, the magnetic head 1 as shown in FIGS. 1 and 2 will be described.

The magnetic head 1 according to the present invention comprises a pair of magnetic core halves 2 and 3 joined by metal diffusion bonding. The pair of magnetic core halves 2 and 3 are made of MnO—N
a non-magnetic substrate 4 made of an iO-based non-magnetic material, and a metal magnetic thin film 5 formed on an inclined surface 4a of the non-magnetic substrate 4
And a low melting point glass 6 formed on the non-magnetic substrate 4 so as to cover the metal magnetic thin film 5. Further, at least one of the pair of magnetic core halves 2 and 3 is formed with a thin-film coil 7 for excitation and / or detection of an induced electromotive force.

In the magnetic head 1, in a state where the pair of magnetic core halves 2 and 3 are joined via the non-magnetic film 8, the metal magnetic thin film 5 is formed as shown in FIG. The magnetic core 9 is formed as shown in FIG. In the magnetic head 1, when the magnetic recording medium slides in a direction indicated by an arrow A in FIG. 2, the magnetic core 9 reproduces the signal magnetic field recorded on the magnetic recording medium, or the magnetic core 9 generates the signal magnetic field. It operates by recording on a recording medium.

In order to adjust the contact state of the magnetic head 1 with the magnetic recording medium, the sliding surface 10 of the magnetic recording medium is moved in the direction of sliding of the magnetic recording medium indicated by an arrow A in FIG. It is formed in an arc shape in parallel. The magnetic head 1 is used to adjust the contact area with the magnetic recording medium.
A contact width regulating groove 11 is formed. The contact width regulating grooves 11 are formed on both side surfaces of the magnetic head 1 in parallel with the sliding direction A of the magnetic recording medium.

In the magnetic head 1, the metal magnetic thin film 5 is formed of a material exhibiting soft magnetism such as sendust (Fe-Al-Si alloy). The metal magnetic thin film 5 is formed on an inclined surface 4 a formed obliquely at a predetermined angle on the non-magnetic substrate 4. Therefore, when the pair of magnetic core halves 2 and 3 on which the metal magnetic thin film 5 is formed are joined via the non-magnetic film 8, the magnetic core 9 becomes as shown in FIG.
It is arranged obliquely to the sliding direction A of the magnetic recording medium.

The metal magnetic thin film 5 is configured so that its cross section has a substantially U-shape. That is, the metal magnetic thin film 5 is formed on the joining surface 2 of the magnetic core halves 2 and 3.
A substantially central portion of the end surfaces on the sides a and 3a is formed as a concave portion 5a.

For this reason, the metal magnetic thin film 5 is divided by the joining surfaces 2 a and 3 a of the magnetic core halves 2 and 3 in the front-rear direction and is exposed from the low melting point glass 6. And has the following. The front butting surface 12 of one magnetic core half 2 and the front butting surface 12 of the other magnetic core half 3 are butted with the nonmagnetic film 8 interposed therebetween to form a front gap 14. Also, the rear butting surface 13 of one magnetic core half 2 and the rear butting surface 13 of the other magnetic core half 3 are butted via the nonmagnetic film 8 to form a back gap 15.

The metal magnetic thin film 5 has a bonding surface 2a,
3a, the thin film coil 7 having the rear butting surface 13 substantially at the center.
Has a coil forming recess 16 formed therein. A coil connection terminal 17 is formed in the coil forming recess 16 near the rear butting surface 13. The thin-film coil 7 is formed in the coil-forming recess 16, and the end on the center side is connected to the coil connection terminal 17.

The coil connection terminals 17 are formed with their heights adjusted so as to form the same surfaces as the joining surfaces 2a, 3a of the pair of magnetic core halves 2, 3. In the magnetic head 1, when the pair of magnetic core halves 2 and 3 are joined, the pair of coil connecting terminals 17 are also joined. Thus, in the magnetic head 1, when the pair of magnetic core halves 2 and 3 are joined, the pair of thin-film coils 7 are electrically connected.

The outer peripheral end of the thin-film coil 7 is led out to the side opposite to the sliding surface 10 of the recording medium. External connection terminals 18 are formed on the pair of magnetic core halves 2 and 3 on the side opposite to the sliding surface 10 of the recording medium. The outer peripheral end of the thin-film coil 7 is connected to the external connection terminal 18.

The external connection terminals 18 are exposed to the side surface of the magnetic head 1 so that they can be connected to the outside by the thin film coil 7.
And can be electrically connected. The pair of external connection terminals 18 are formed at positions where the heights of the pair of magnetic core halves 2 and 3 are different so that a short circuit does not occur when the pair of magnetic core halves 2 and 3 are joined. Have been.

The nonmagnetic film 8 is formed between the front butting surfaces 12 and the rear butting surfaces 13 of the pair of magnetic core halves 2 and 3 in the magnetic head 1 as described above. Thereby, the magnetic core 9 functions as the front gap 14 and the back gap 15. The non-magnetic film 8 is formed on the bonding surfaces 2a and 3a of the pair of magnetic core halves 2 and 3, respectively, and is subjected to metal diffusion bonding, as described later, to thereby form the pair of magnetic core halves. It has the function of joining and integrating the two and three.

By the way, in the magnetic head 1, FIG.
As shown in FIG. 2, the non-magnetic film 8 is formed on the sliding surface 10 over the entire width of the sliding surface 10 as well as the front gap 14. Therefore, the magnetic head 1 is formed in a smooth circular arc shape without the sliding surface 10 having a step.

Therefore, in the magnetic head 1, when the magnetic recording medium slides on the sliding surface 10, wear particles of the magnetic recording medium do not accumulate on the sliding surface 10. Therefore, the magnetic head 1 does not damage the magnetic recording medium due to the abrasion powder or the like.

Further, since the magnetic head 1 has a larger area in which the non-magnetic film 8 is formed as compared with the conventional bulk thin-film type magnetic head, the bonding strength of the non-magnetic film 8 by metal diffusion bonding is higher. .

Therefore, the magnetic head 1 can prevent the pair of magnetic core halves 2 and 3 from being separated after joining, that is, so-called chip cracking. Therefore, the yield of the magnetic head 1 can be improved when it is manufactured.

In the magnetic head 1, the non-magnetic substrate 4 is made of a MnO-NiO-based non-magnetic material, but the present invention is not limited to this configuration. The nonmagnetic substrate 4 may be made of calcium titanate, barium titanate, zirconium oxide (zirconia), alumina, alumina titanium carbide, SiO ₂ , Zn ferrite, crystallized glass, high hardness glass, or the like.

In the magnetic head 1, the non-magnetic substrate 4 has the inclined surface 4a formed obliquely at a predetermined angle. However, the inclined surface 4a is formed in a circular or polygonal shape, for example. You may. However, the slope 4a is 45
It is desirable to form at an angle of about degrees. Thereby, the track width accuracy of the magnetic head 1 is improved.

Further, in the magnetic head 1, the metal magnetic thin film 5 is formed of a material exhibiting soft magnetism such as Sendust (Fe-Al-Si alloy), but the present invention is not limited to such a structure. Absent. The metal magnetic thin film 5 is made of, for example, Fe-Ta-N alloy, Fe-Al alloy, Fe-Si
-Co alloy, Fe-Ga-Si alloy, Fe-Ga-Si
-Ru alloy, Fe-Al-Ge alloy, Fe-Ga-Ge
Alloy, Fe-Si-Ge alloy, Fe-Co-Si-Al
An alloy or a crystalline alloy such as an Fe—Ni alloy may be used. Alternatively, the metal magnetic thin film 5 is made of Fe, Co,
An alloy composed of one or more elements of Ni and one or more elements of P, C, B, Si, or
1, Ge, Be, Sn, In, Mo, W, Ti, Mn,
Metal-metalloid amorphous alloys typified by alloys containing Cr, Zr, Hf, Nb, etc .;
It may be made of an amorphous alloy such as a metal-metal amorphous alloy containing a transition metal such as f or Zr and a rare earth element as main components. Further, the metal magnetic thin film 5
May be a nitrided soft magnetic alloy or a carbonized soft magnetic alloy.

The metal magnetic thin film 5 may be constituted by a metal magnetic thin film composed of a single layer. However, it is preferable that the metal magnetic thin film 5b and the magnetic thin film layer 5c are alternately laminated. Thus, the magnetic head 1 can have high sensitivity in a higher frequency range. In the example of FIG. 3, the magnetic head 1 having three magnetic thin film layers 5c is shown.

Further, in the above-described embodiment, the nonmagnetic film 8 is formed of Au.
It may be formed of at least one selected from noble metals suitable for metal diffusion bonding such as g, Pd, and Pt.

The magnetic head 1 configured as described above is
When reproducing a magnetic signal recorded on the magnetic recording medium, a signal magnetic field from the magnetic recording medium is applied around the front gap 14. When the direction of the applied signal magnetic field changes, the direction of the magnetic flux flowing through the magnetic core 9 changes. As a result, in the magnetic head 1, electromagnetic induction occurs, and a predetermined current flows through the thin-film coil 7.

When a magnetic signal is recorded on a magnetic recording medium using the magnetic head 1, a predetermined current is supplied to the thin-film coil 7. And this magnetic head 1
Then, the magnetic core 9 is generated by the magnetic field generated from the thin film coil 7.
A predetermined magnetic flux flows through the. Thereby, this magnetic head 1
Then, a leakage magnetic field is generated across the front gap 14. The magnetic head 1 records a magnetic signal by applying the leakage magnetic field to a magnetic recording medium.

Next, a method of manufacturing the above-described magnetic head 1 will be described.

The magnetic head 1 is formed on the same substrate with the magnetic core halves 2 and 3 connected in a plurality of rows. The substrate is provided with a plurality of magnetic core halves 2, 3
Are separated for each row in which is formed, to form a magnetic core half block. The magnetic core half blocks are joined and integrated by metal diffusion bonding to form a magnetic head block. The magnetic head 1 is completed by separating the magnetic head block into individual magnetic heads 1.

First, to manufacture the magnetic head 1,
As shown in FIG. 4, a substantially flat substrate 21 is prepared. This substrate 21 is to be the non-magnetic substrate 4 of the magnetic head 1, and is made of a non-magnetic material such as MnO-NiO. The substrate 21 has a thickness of about 2 mm, for example.
The length and width are set to about 30 mm.

Next, as shown in FIG.
For example, a plurality of magnetic core forming grooves 24 are formed with a grindstone or the like so as to have an angle of about 45 degrees with respect to one main surface 21a.
Are formed in parallel. Then, a plurality of inclined surfaces 21b are formed in the substrate 21 by the magnetic core forming grooves 24 formed in the first groove processing. Inclined surface 21b
Are the inclined surfaces 4a in the magnetic head 1.

The inclined surface 21b formed here is
It may be circular or polygonal. Also, the inclined surface 21b
Is preferably about 25 to 60 degrees with respect to the plane of the substrate 21, but is more preferably about 35 to 50 degrees in consideration of prevention of pseudo gap and track width accuracy.
The magnetic core forming groove 24 formed by the first groove processing had a depth of 130 μm and a width of 150 μm.

Next, as shown in FIG. 6, a metal magnetic thin film 27 is formed on the entire surface of the substrate 21 on which the inclined surface 21b is formed. In this film forming step, the metal magnetic thin film 27
Is formed so that three metallic magnetic materials are laminated via a nonmagnetic layer. This metal magnetic thin film 27 is formed, for example, by a PVD method such as a magnetron sputtering method or the like.
The film is formed by a VD method or the like.

Further, the metal magnetic thin film 27 is not limited to the one having a plurality of metal magnetic layers, and may be configured to have a single metal magnetic layer. In order to obtain, it is desirable that the metal magnetic layer has a laminated structure in which the metal magnetic layer is divided into a plurality. Thereby, the metal magnetic thin film 27 can reduce the eddy current loss and obtain high sensitivity in a higher frequency band.

In this embodiment, the metal magnetic thin film 27
For example, a Fe-based microcrystalline film of Bs = 1.5T of 4 μm and alumina of 0.15 μm are alternately laminated, and three layers of Fe
A structure having a system microcrystalline film layer was adopted. When the metal magnetic thin film 27 is formed in a plurality of layers, materials such as alumina, SiO ₂ and SiO are used alone or in combination as the non-magnetic layer. The thickness of the non-magnetic layer is set to such an extent that insulation between adjacent metal magnetic layers can be obtained.

Next, as shown in FIG.
A second groove is formed on the surface on which the groove 7 is formed in a direction substantially orthogonal to the magnetic core forming groove 24. In the second groove processing, a separation groove 28 formed for separating the magnetic core 9 into a predetermined size, and a winding for forming a magnetic gap in each magnetic core 9 separated by the separation groove 28. Wire groove 29
And are formed.

At this time, portions other than the metal magnetic thin film 27 formed on the inclined surface 21b, that is, the metal magnetic thin film 27 formed at the bottom of the magnetic core forming groove 24 are removed by grinding.

Here, the separation groove 28 is a groove for forming each magnetic core 9 by magnetically separating the magnetic core 9 in the front-back direction on the substrate 21 and forming a closed magnetic path in each magnetic core 9. is there. Although two separation grooves 28 are formed in the example of FIG. 7, the separation grooves 28 need to be provided by the number of rows of the magnetic core halves 2 and 3 to be formed. In addition, the separation groove 28 must be formed to have a depth that can completely cut the metal magnetic thin film 27 in order to magnetically separate the magnetic cores 9 arranged in the front-rear direction. is there. Specifically, the separation groove 28 has a depth of 150 μm from the bottom of the magnetic core formation groove 24, that is, 280 μm from the main surface 21 a of the substrate 21.
And the depth.

On the other hand, the winding groove 29 forms a recess 5 a formed in the metal magnetic thin film 27 in the magnetic head 1 described above. Therefore, the winding groove 29 is formed on the magnetic core 9 having the front butting surface 12 and the rear butting surface 13.
In order to form the recess 16 for forming the coil, it is necessary to form the metal magnetic thin film 27 at a depth that does not cut it. Therefore, the cross section of the metal magnetic thin film 27 is exposed on the surface of the winding groove 29.

The shape of the winding groove 29 is determined according to the lengths of the front butting surface 12 and the rear butting surface 13. Here, the width is set to about 140 μm, and And the length of the rear abutting surface 13 was 85 μm. The winding groove 29 may have such a depth that the metal magnetic thin film 27 is not cut. However, if the winding groove 29 is too deep, the magnetic path length becomes longer and the efficiency of magnetic flux transmission may be reduced. The depth of the winding groove 29 depends on the thickness of the thin-film coil 7 formed in a step described later, but is 20 μm here.

Further, the shape of the winding groove 29 is not limited, but here, the front abutting surface 12
The side surface was a 45-degree inclined surface 29a. This allows
The magnetic core 9 has a structure in which the magnetic flux is concentrated on the sliding surface 10 so that the sensitivity is improved.

Next, as shown in FIG. 8, a low-melting glass melted on one main surface 21a of the substrate 21 on which the magnetic core forming groove 24, the separation groove 28 and the winding groove 29 are formed as described above. Fill 30.

In this filling step, the metal magnetic thin film 5
Is filled with the low melting point glass 30 at such a temperature as to obtain good soft magnetic properties. Thereby, before this filling process,
The heat treatment step for the metal magnetic thin film 5 to obtain good soft magnetic properties can be omitted. In other words, in the present embodiment, in the filling step, the low-melting glass 30 is heated and melted, but when the low-melting glass 30 is filled, the low-melting glass 30 is melted.
Is transmitted to the metal magnetic thin film 5, the metal magnetic thin film 5 is heat-treated, and good soft magnetic characteristics are obtained.

Therefore, according to the method of manufacturing a magnetic head according to the present invention, this filling step also serves as a heat treatment step of the metal magnetic thin film 5, thereby simplifying the manufacturing step of the magnetic head and improving the production efficiency. Can be.

In this filling step, a nonmagnetic material having a viscosity of 10 ² to 10 ⁶ Pa · s at the heat treatment temperature of the metal magnetic thin film 5 as described above is selected as the low-melting glass 30. The substrate 21 is filled. As a result, the low-melting glass is completely filled over the entire surface of the substrate 21 on which the magnetic core forming groove 24, the separation groove 28, and the winding groove 29 are formed. Can be.

When the viscosity of the low-melting glass 30 at the above-mentioned heat treatment temperature is less than 10 ² Pa · s, the reaction with the metal magnetic thin film 5 becomes significant in this filling step, and the magnetic properties of the metal magnetic thin film 5 Will deteriorate. The low-melting glass 30 has a viscosity of 10 at the heat treatment temperature described above.
If it exceeds ⁶ Pa · s, it will be difficult to completely fill the substrate 21 at every corner. Therefore, as the low-melting glass 30, it is important to select a nonmagnetic material having a viscosity of 10 ² to 10 ⁶ Pa · s at the above-described heat treatment temperature.

It is more desirable that the low-melting glass 30 has a viscosity at the above-mentioned heat treatment temperature of 10 ³ to 10 ⁵ Pa · s. As a result, the low-melting glass 30 is more completely filled completely into the corners of the substrate 21.

In this embodiment, the metal magnetic thin film 5
Obtains a soft magnetic property of Hc ≦ 30 A / m by heat treatment at 520 ° C., so that the low-melting glass 30 is SiO ₂ ,
A glass material containing PbO, B ₂ O ₃ , and Bi ₂ O ₃ as main components and having a viscosity at 520 ° C. of about 10 ^4.5 Pa · s was used.

Thereafter, the low-melting glass 30 is cooled and solidified, and the surface of the solidified low-melting glass 30 is ground to perform a flattening process.

At this time, if the amount of grinding of the low-melting glass 30 is too large, the exposed width of the substrate 21 becomes large.
Since the substrate 21 and the low-melting glass 30 have different etching rates, if the width of the substrate 21 exposed from the low-melting glass 30 is too large, the substrate 21 and the low-melting glass 30 will be formed in a later-described thin film coil forming step. There is a possibility that a step may be generated between the first and the second. Therefore, in this flattening process, it is desirable to grind the low-melting glass 30 so that the substrate 21 is exposed with a width smaller than the width of the innermost peripheral portion of the thin-film coil 7.

Next, as shown in FIG.
By performing grinding on 0 using a grindstone, etc.,
The terminal groove 31 is formed. The terminal groove 31 was formed so as to be located immediately above the above-described separation groove 28. Terminal groove 31
Is not limited in its shape, width and depth,
Here, the width and the depth were set to 100 μm. Then, a good conductor such as Cu is filled in the terminal groove 31 by plating or the like. After that, the flattening process is performed again. The good conductor such as Cu filled in the terminal groove 31 serves as the external connection terminal 18 in the magnetic head 1 described above.

Next, as shown in FIG. 10, the low-melting glass 30 is subjected to an etching process to form a coil-forming recess 16 and a thin-film coil 7 is formed in the coil-forming recess 16. I do.

The coil forming concave portion 16 is formed in a substantially rectangular shape with the rear abutting surface 13 being substantially at the center, and the rear abutting surface 1 is formed.
It is formed by performing an etching process on a portion excluding 3 and the coil connection terminal 17. The coil forming recess 16 has a groove 16a extending from one end to the terminal groove 31.

Then, a thin film coil 7 is formed in the coil forming recess 16. The thin-film coil 7 has one end 7a disposed on a coil connection terminal 17 and a rear abutting surface 1a.
It has a shape wound many times so as to draw a circle centered at 3. The thin-film coil 7 is drawn out into a groove 16 a formed at one end of the coil forming recess 16, and the other end 7 b is electrically connected to an external connection terminal 18 made of a good conductor filled in a terminal groove 31. Connecting.

When the thin film coil 7 is formed, first, the above-described coil shape is patterned by a photoresist. Next, Cu is formed in the coil forming recess 16.
Is formed into a thin film to a thickness of about 3 μm by a technique such as electrolytic plating. Then, by removing the photoresist, the thin film coil 7 having a patterned coil shape can be formed. In forming the thin-film coil 7, not only the above-described electrolytic plating method but also a sputtering method or a vapor deposition method can be used.

Next, a protective layer (not shown) for protecting the thin-film coil 7 from contact with the outside air is formed. This protective layer is formed so as to bury the coil forming recess 16 in which the above-described thin film coil 7 is formed. The protective layer is preferably formed of a non-magnetic insulating material that is not removed by the oxygen ashing.

Specifically, as the non-magnetic insulating material, Al
Examples thereof include oxides such as ₂ O ₃ , Ta ₂ O ₅ , SiO ₂ , ZrO ₂ , and TiO ₂ and inorganic substances such as glass. Here, as the protective film, Al ₂ O ₃ was sputtered to a thickness of 0.4 μm.
m was formed over the entire surface of the substrate 21. At this time, the protective film also covers the front butting surface 12 and the rear butting surface 13 which are exposed on one main surface of the substrate 21, but the portions covering these portions are removed in a step described later. Note that this protective film can be formed only in a predetermined region by using a so-called mask sputtering method or a lift-off method. Examples of the method for forming the protective film include, besides the sputtering method, an evaporation method and spin coating of coating type SiO ₂ .

Next, as shown in FIG. 11, the nonmagnetic film 8 is applied to the main surface of the low-melting glass 30 filled in the substrate 21.
Is formed. The non-magnetic film 8 serves as a gap material for the magnetic core 9 and as an adhesive for metal diffusion bonding. In this film forming process, before forming the nonmagnetic film 8, the main surface of the low-melting glass 30 is subjected to mirror finishing.

In this mirror finishing process, the surface to be mirror-finished is the bonding surface 2 of the pair of magnetic head halves 2 and 3.
a, 3a, it is necessary to perform the process with sufficient accuracy.
Specifically, in the magnetic head 1 according to the present embodiment,
If the level difference between the joining surfaces 2a and 3a exceeds 35 nm, the joining strength when joining the pair of magnetic head halves 2 and 3 becomes extremely weak, and chip cracks occur in the processing after joining. It is easy to occur.

Therefore, in the present embodiment, a polisher made of Sn—Sb having a Brinell hardness H _B of about 20 is used, and a slurry in which diamond abrasive grains having an average grain size of about 0.25 μm are dispersed as an abrasive is used. Then, mirror polishing was performed by polishing the surface on which the above-mentioned protective layer was formed. Since Brinell hardness H _B of the metallic magnetic film 5 and the thin film coil 7 is about 80, the hardness ratio of the polisher against the hardness of the metallic magnetic film 5 and the thin film coil 7 as a workpiece is approximately 0.25 It is.

The polishing means that a slurry in which an abrasive for polishing is dispersed in water or oil or the like is supplied between a polisher having a sufficiently flat surface and a workpiece while the polisher is processed. This is a method of searching for the surface of a workpiece by rotating the workpiece while pressing it against the surface of the workpiece. Then, in the polishing, the protrusions on the surface of the workpiece are ground and removed by the abrasive, and the flatness of the polisher is transferred to the workpiece.

As described above, the ratio of the hardness to the hardness of the metal magnetic thin film 5 or the thin film coil 7 as the workpiece is about 0.25.
By surface processing using a polisher that is
The step on the mirror-finished surface is at most 25 nm or less, and a sufficiently smooth plane can be obtained. In addition, when the polishing is performed with the ratio of the hardness of the polisher to the hardness of the metal magnetic thin film 5 and the thin film coil 7 to be processed being about 0.25, a sufficient grinding rate can be obtained, and mirror finishing can be performed in a short time. it can.

In this mirror finishing step, the ratio of the hardness of the polisher to the metal magnetic thin film 5 or the thin film coil 7 to be processed is desirably 0.15 to 0.6. Thus, the production efficiency is not sacrificed due to the low grinding rate, and the step on the mirror-finished surface does not exceed 25 nm.

As described above, the surface on which the non-magnetic film 8 is formed is mirror-finished so that when the non-magnetic film 8 is formed on this surface, the entire surface of the non-magnetic film 8 is formed. To perform metal diffusion bonding. Therefore, on the sliding surface 10 side of the joining surfaces 2a and 3a of the pair of magnetic core halves 2 and 3,
The nonmagnetic film 8 can be formed over the entire width of the sliding surface 10.

Next, a non-magnetic film 8 is formed. Non-magnetic film 8
Specifically, a noble metal such as Au is formed to a thickness of about 100 nm by, for example, a sputtering method. At this time, the non-magnetic film 8 is connected to the front butting surface 12 and the rear butting surface 13 of the metal magnetic thin film 5 by the coil connecting terminal 1.
7 and the main surface of the low-melting glass 30, it has sufficient bonding strength when the pair of magnetic core halves 2 and 3 are metal diffusion-bonded.

The non-magnetic film 8 is not limited to Au, but is suitable for low-temperature metal diffusion bonding.
What is necessary is just to form from the metal whose diffusion coefficient is large and the oxide layer is hard to be formed on the surface. Specifically, for example, A
It may be formed of at least one selected from noble metals such as g, Pd, and Pt. The method of forming the nonmagnetic film 8 is not limited to the sputtering method, but may be formed by, for example, an electrolytic plating method, a vapor deposition method, or the like. Further, the thickness of the non-magnetic film 8 is not limited, and may be formed with a thickness sufficient for metal-diffusion bonding of the pair of magnetic core half-blocks 33 and in consideration of the gap length.

As will be described later, the thickness of the nonmagnetic film 8 as a whole when the magnetic core half-block 33 is joined is the gap length of the magnetic core 9 formed by the metal magnetic thin film 5.

Next, as shown in FIG. 12, a side groove 32 which is a square groove is formed so as to cross the front butting surface 12 facing the one main surface in parallel. Then, the magnetic core half 2,
The magnetic core half block 33 is formed by cutting the substrate 21 in which a plurality of rows 3 are formed in parallel so that one magnetic core half 2 and the other magnetic core half 3 are arranged in each row.

The side grooves 32 are formed by grinding, and have, for example, a depth of 50 μm and a width of 400 μm. When the side grooves 32 are formed, the side grooves 32
One end of the front abutting surface 12 is exposed on the side surface of. The side grooves 32 are formed to expose the upper end of the front butting surface 12 as a positioning index when the pair of magnetic core half blocks 33 are butted, as described later.

Next, as shown in FIG. 13, metal diffusion bonding is performed by accurately positioning the pair of magnetic core half blocks 33.

At this time, the upper ends of the front butting surfaces 12 facing the side grooves 32 are opposed to each other, so that accurate positioning is achieved. In this way, by correctly opposing the upper end of the front butting surface 12 facing the side groove 32, the rear butting surface 13 and the coil connection terminal 17 can be accurately faced.

Then, by applying a predetermined temperature and pressure to the pair of magnetic core half-blocks 33, the non-magnetic films 8 are diffused, and the pair of magnetic core half-blocks 33 are joined and integrated. The manufactured magnetic head block 38 is manufactured. In the present embodiment, 35
At a temperature of 0 ° C., a pair of magnetic core half blocks 33
Was subjected to metal diffusion bonding.

Next, as shown in FIG. 14, the magnetic head block 38 is separated into individual magnetic heads 1.

At this time, first, the magnetic head block 38
Is cut in the longitudinal direction in order to expose a surface serving as a sliding surface 10 on which the magnetic recording medium slides. Then, the exposed surface of the magnetic head block 38 is subjected to cylindrical cutting so as to have a cylindrical shape. As a result, this surface becomes the sliding surface 10 of the magnetic head 1. Thereafter, the contact width regulating groove 11 is ground on the magnetic head block 38. The contact width regulating grooves 11 are formed at portions corresponding to both side surfaces of the sliding surface 10 of each magnetic head 1 separated from the magnetic head block 38.

The magnetic head block 38 corresponds to FIG.
4 are separated into individual magnetic heads 1 by cutting at the portion indicated by the line BB in FIG.

In this embodiment, the sliding surface 10 is polished so that the front gap 14 of the magnetic head 1 has an azimuth angle of 20 degrees, and the contact width regulating groove 11 is ground. It is assumed that the cut surface of the magnetic head block 38 is inclined and separated. The magnetic head block 38 performs the above-described polishing of the sliding surface 10, grinding of the contact width regulating groove 11, and cutting of the individual magnetic heads 1 so that the front gap 14 has a predetermined azimuth angle. The azimuth angle is not limited to 20 degrees.

In this embodiment, the pair of magnetic core half blocks 33 are joined and integrated to form a magnetic head block 38 and then separated into individual magnetic heads 1. After the block 33 is separated into individual magnetic core halves, the magnetic head 1 may be formed by joining and integrating a pair of magnetic core halves.

In the following, a gap is formed between the first magnetic head manufactured according to the present embodiment and the butting portion of the pair of magnetic core halves on the sliding surface of the magnetic recording medium as shown in FIG. A description will be given of a case in which a second magnetic head having the same is manufactured and a measurement test of the accumulation amount of abrasion powder and the like is performed.

In this measurement test, the first magnetic head and the second magnetic head were bonded to a DVC head base, and the external connection terminals and the external terminal plate of the head base were connected by wire bonding. Then, a measurement test of the accumulated amount of wear powder and the like was performed under the following conditions.

Measurement test of accumulated amount of wear powder etc. Magnetic recording medium: ME tape for DVC Recording / reproducing device: Digital VTR for consumer use (DVC) As a result of the measurement test of the accumulation amount of wear powder, the second magnetic head After about 30 runs, accumulation of wear powder and the like was observed in the gaps on the sliding surface. However, since the first magnetic head has no air gap, accumulation of abrasion powder and the like was naturally not observed.

From the results of this measurement test, the first magnetic head according to the present embodiment can prevent accumulation of abrasion powder and the like on the sliding surface that may damage the sliding magnetic recording medium. You can see that you can do it.

[0093]

As described above, in the magnetic head according to the present invention, the nonmagnetic film that forms the magnetic gap is formed over the entire width of the sliding surface of the magnetic recording medium. Therefore, in such a magnetic head, the pair of magnetic core halves adhere to each other without forming a gap on the sliding surface, and the joining strength of the pair of magnetic core halves improves. Further, in such a magnetic head, abrasion powder or the like of the magnetic recording medium is not accumulated in the butted portion of the pair of magnetic core halves, and the sliding magnetic recording medium is not damaged.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a magnetic head according to the present invention.

FIG. 2 is a perspective view of a main part showing a sliding surface of the magnetic head.

FIG. 3 is an enlarged view of a main part showing a sliding surface of the magnetic head.

FIG. 4 is a view for explaining the method for manufacturing the magnetic head according to the present invention, and is a perspective view showing a substrate.

FIG. 5 is a view for explaining the same method, and is a perspective view showing a substrate on which first groove processing has been performed.

FIG. 6 is a diagram for explaining the same method, and is a perspective view showing a substrate on which a metal magnetic thin film is formed.

FIG. 7 is a view for explaining the same method, and is a perspective view showing a substrate on which a second groove processing has been performed.

FIG. 8 is a diagram for explaining the same method, and is a perspective view showing the substrate in a state where each groove is filled with low-melting glass.

FIG. 9 is a diagram for explaining the same method, and is a perspective view showing a substrate in which terminal grooves are formed in low-melting glass.

FIG. 10 is a view for explaining the same method, and is a perspective view of a principal part showing a substrate on which a concave portion for forming a coil is formed.

FIG. 11 is a diagram for explaining the same method, and is a perspective view of a main part showing a substrate on which a nonmagnetic film is formed.

FIG. 12 is a diagram for explaining the same method, and is a perspective view showing a magnetic core half block.

FIG. 13 is a view for explaining the same method, and is a perspective view showing a state where a pair of magnetic core half blocks are butted.

FIG. 14 is a diagram for explaining the same method, and is a perspective view showing a magnetic head block.

FIG. 15 is an enlarged view of a main part showing a sliding surface of a conventional magnetic head.

[Explanation of symbols]

Reference Signs List 1 magnetic head, 2, 3 magnetic core half, 4 non-magnetic substrate, 4a inclined surface, 5 metal magnetic thin film, 5a concave portion, 6
Low-melting glass, 8 non-magnetic film, 9 magnetic core, 10 sliding surface, 11 width control groove, 12 front butting surface, 1
3 Rear abutment surface, 14 Front gap, 15 Back gap, 16 Coil forming recess, 18 Terminal groove

Claims (1)

[Claims] 1. A pair of magnetic core halves having a metal magnetic thin film formed obliquely on a substrate, having a concave portion in which a thin film coil is formed, and having a butted surface made flat by a nonmagnetic material. A magnetic gap is formed by abutting the end faces of the metal magnetic thin film so as to face each other with a non-magnetic film therebetween, and the non-magnetic film is formed over the entire width of the sliding surface of the magnetic recording medium. A magnetic head, comprising: