JPH06282821A - Composite type thin-film magnetic head and manufacture thereof - Google Patents

Abstract

PURPOSE:To eliminate a leakage of a magnetic flux from a lower yoke of a head and thereby to keep a recording characteristic sufficient by method wherein the lateral side part of a non-magnetic layer is made vertical to the main surface of a ferrite base and, while the depth of the nonmagnetic layer is specified, the position of a gap depth is made fixed irrespective of the depth of this later. CONSTITUTION:An SiO2 insulation film 3 to be a first gap G1 is formed on a magnetic ferrite base 1 and a second yoke 4 formed of Ni-Fe, etc., is provided thereon and covered with a trapezoidal insulation layer 5. Inside the layer 5, a bias lead wire 6 and an MR element 8 are formed, a second gap G2 is formed in the front of the layer 5 and a third yoke 11a is provided thereon. In the rear of the yoke 4, an insulation layer 25 in the same shape is formed, a coil 7 is provided inside this layer and a first yoke 11b of Ni-Fe being connected magnetically with the yoke 4 is formed thereon. Between the yoke 4 and the base 1, besides, a nonmagnetic layer 3 of which a depth (h) from the main surface of the base 1 is 15 to 50mum and which is constituted of glass or the like is formed and thereby a leakage of a magnetic flux is checked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head, and more particularly to a composite thin film magnetic head having thin film magnetic heads for reproducing and recording, reproducing and reproducing and recording and recording formed on the same substrate. It is about structure.

[0002]

2. Description of the Related Art Conventionally, with the advancement of magnetic recording, a thin film magnetic head for forming a magnetic head on a substrate has been widely used. Further, in recent years, development of a thin film magnetic head for reproduction and a thin film magnetic head for recording, a thin film magnetic head for reproduction or a composite thin film magnetic head in which thin film magnetic heads for recording are formed on the same substrate has been developed. It is being advanced.

Here, an example of a conventional composite type thin film magnetic head will be described with reference to FIG. FIG. 11 is a sectional view showing the structure of a conventional composite type thin film magnetic head.

FIG. 11 shows a composite type thin film magnetic head in which a thin film magnetic head for reproduction and a thin film magnetic head for recording are formed on the same substrate.

Referring to FIG. 11, a reproducing thin film magnetic head 100 is provided on a magnetic ferrite substrate 1 made of Mn-Zn ferrite, Ni-Zn ferrite, etc., and a recording thin film is provided behind the reproducing thin film magnetic head 100. The magnetic head 200 is formed.

An insulating film 3 made of SiO ₂ or the like is formed on the magnetic ferrite substrate 1 to form the first gap G1. Ni-F is formed on the insulating film 3.
A second yoke 4 made of e, FeAlSi, amorphous (Co-Zr) or the like is formed. An insulating layer 5 having a substantially trapezoidal cross section is formed on the upper surface of the second yoke 4. A bias lead wire 6 and an MR element 8 are formed inside the insulating layer 5. The insulating layer 5 is
A second gap G2 is formed in the front, and a third yoke 11a having a predetermined gap is formed on the upper surface of the second gap G2 substantially above the MR element 18.

The above-mentioned third yoke 11a, second yoke 4, insulating layer 5, bias lead wire 6 and MR element 8 constitute a reproducing thin film magnetic head 100. In addition, a closed magnetic circuit of the third yoke 11a → the second yoke 4 is formed.

Next, behind the second yoke 4, the insulating layer 2 having a substantially trapezoidal cross section is formed on the magnetic ferrite substrate 1.
5 is formed. The coil 7 is provided inside the insulating layer 25. On the upper surface of the insulating layer 25, Ni—Fe, FeAlS magnetically connected to the second yoke 4 is formed.
A first yoke 11b made of i, amorphous (Co-Zr) or the like is provided. Furthermore, this first yoke 1
A permalloy plating film 12 is formed on the upper surface of 1b. As described above, the second yoke 4 and the first yoke 11 described above
b, magnetic ferrite substrate 1, insulating layer 25 and coil 7
Thus, the recording thin film magnetic head 200 is configured.

A closed magnetic circuit is formed by the above-mentioned second yoke 4 → first yoke 11b and the magnetic ferrite substrate 1.

The magnetic ferrite substrate 1 is made of non-magnetic material filled with a non-magnetic material such as glass in order to prevent magnetic flux leakage between the second yoke 4 and the magnetic ferrite substrate 1 and to prevent deterioration of magnetic efficiency. It has a layer 2.

On the other hand, a passivation film 13 is formed on the upper surfaces of the third yoke 3 and the permalloy plating film 12, the passivation film 13 is planarized, and a protective film 14 is adhered by an epoxy adhesive or the like. ing.

With the structure described above, a thin film magnetic head having the reproducing thin film magnetic head 100 and the recording thin film magnetic head 200 is formed.

[0013]

However, the composite type thin film magnetic head according to the above-mentioned prior art has the following problems.

12 to 14 are sectional views showing the problems of the composite type thin film magnetic head, and are enlarged sectional views of the area within the circle indicated by H in FIG.

First, referring to FIG. 12, the nonmagnetic layer 2 is not sufficiently filled in the groove 1a provided in the ferrite substrate 1, and the nonmagnetic layer 2 is formed at a position lower than the main surface of the ferrite substrate 1. When the main surface is filled, the second yoke 4 is formed along each main surface, so that a disconnection portion occurs in the second yoke 4 at the step portion D. Therefore, there is a problem that the magnetic efficiency is reduced.

Next, referring to FIG. 13, even if the step between the main surface of ferrite substrate 1 and the main surface of non-magnetic layer 2 is relatively gentle, step portion D causes insulation film 3 to be formed. Since the film thickness of is smaller than the normal film thickness (L2) (L1), there is a problem that the magnetic efficiency due to magnetic flux leakage in this portion is reduced, as in the above. .
Next, with reference to FIG. 14, there is shown a case where the main surface of the non-magnetic layer 2 filled in the groove 1a is higher than the main surface of the ferrite substrate 1. In this case, the position of the gap depth “0” varies due to the distance L3 of the portion where the non-magnetic layer 2 is raised on the main surface of the ferrite substrate 1.
There was a problem that the output of magnetic characteristics was not constant.

The present invention has been made to solve the above problems, and eliminates the decrease in magnetic efficiency of the composite thin film magnetic head, and further provides a composite thin film magnetic head having a predetermined recording / reproducing output and its manufacture. The purpose is to provide a method.

[0018]

In a composite type thin film magnetic head according to the present invention, a ferrite substrate is provided with a gap from the ferrite substrate so as to form a first gap with the ferrite substrate. First stacked
Composite type in which a first thin film magnetic head having a yoke and a second thin film magnetic head having a second yoke and a third yoke that are laminated with a gap so as to form a second gap are laminated In the thin-film magnetic head, the first yoke and the second yoke share at least a part of the same layer, and the ferrite substrate has an inner surface on the main surface from the main surface to a predetermined depth. A non-magnetic layer is provided inside the groove which is perpendicular to the main surface and parallel to the main surface.

In the composite thin film magnetic head according to the present invention, more preferably, the depth of the groove from the main surface is in the range of 15 μm to 50 μm, and the inner side surface and the bottom surface have a radius. It is continuously connected by an arc of 10 μm or less.

Next, the method of manufacturing a composite type thin film magnetic head according to the present invention includes the following steps.

First, 50μ from the main surface of the ferrite substrate
Grooves are formed having a depth of more than m, the inner surface being perpendicular to the main surface and the bottom surface being parallel to the main surface. Then, a nonmagnetic material is deposited inside the groove so that the height of the groove from the bottom surface exceeds 50 μm.

Next, the height from the bottom surface of the groove to the main surface and the height to the main surface of the nonmagnetic material are 15 μm.
Each main surface is simultaneously processed so as to have a thickness of ˜50 μm. Then, a first yoke having a first yoke that is laminated with a gap on the ferrite substrate so as to form a first gap on the main surface of the ferrite substrate and the main surface of the non-magnetic body. Thin film magnetic head is formed.

Next, a second yoke having the above-mentioned first yoke and a second yoke having the same layer at least partially as the second yoke, which are laminated with a gap so as to form a second gap, and a third yoke. Thin film magnetic head is formed.

[0024]

According to the composite type thin film magnetic head and the method of manufacturing the same according to the present invention, the side surface of the non-magnetic layer is formed so as to be perpendicular to the main surface of the ferrite substrate. The position of the gap depth “0” is constant regardless of the depth from. In addition, the depth of the non-magnetic layer is 1
By setting the thickness in the range of 5 μm to 50 μm, leakage of magnetic flux from the lower yoke of the thin film magnetic head is prevented, sufficient recording characteristics are maintained, and cracks are generated in the ferrite substrate during the manufacturing process. It becomes possible to prevent it.

Further, by simultaneously processing the ferrite substrate and the non-magnetic material, the main surfaces of the ferrite substrate and the non-magnetic layer can be made to coincide with each other, which adversely affects the thin film magnetic head formed on the main surface of the ferrite substrate. A thin film magnetic head can be formed without applying Also,
By continuously connecting the inner side surface and the bottom surface of the groove portion with an arc having a radius of 10 μm or less, the gap depth can be reduced even when the ferrite substrate and the non-magnetic body are simultaneously processed during mass production, even if the variation is within 15 to 50 μm. The position of "0" becomes constant, and it is possible to improve the yield in the manufacturing process.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the composite type thin film magnetic head according to the present invention will be described below. FIG. 1 is a plan view of a composite type thin film magnetic head in this embodiment. Figure 2
FIG. 2 is a sectional view taken along the line AA in FIG. Referring to both figures, a reproducing thin film magnetic head 100 is provided on a magnetic ferrite substrate 1 made of Mn—Zn ferrite, Ni—Zn ferrite, etc., and a recording thin film magnetic head 200 is provided behind the reproducing thin film magnetic head 100. And are formed.

On the magnetic ferrite substrate 1, an insulating film 3 made of SiO ₂ or the like for forming the first gap G1 is formed. Ni-Fe, F is formed on the insulating film 3.
A second yoke 4 made of eAlSi, amorphous (Co-Zr) or the like is formed. An insulating layer 5 having a substantially trapezoidal cross section is formed on the second yoke 4. A bias lead wire 6 and an MR element 8 are formed inside the insulating layer 5. The insulating layer 5 forms a second gap G2 at the front, and the MR layer is formed on the upper surface of the second gap G2.
A third yoke 11a having a predetermined gap is formed substantially above the element 8.

The above-mentioned third yoke 11a, second yoke 4, insulating layer 5, bias lead wire 6 and MR element 8 constitute a reproducing thin film magnetic head 100. In addition, a closed magnetic circuit of the third yoke 11a → the second yoke 4 is formed.

Next, behind the second yoke 4, an insulating layer 25 having a substantially trapezoidal cross section is formed on the magnetic ferrite substrate 1.
Are formed. The coil 7 is provided inside the insulating layer 25. On the upper surface of the insulating layer 25, Ni-Fe, FeAlSi, magnetically connected to the second yoke 4,
First yoke 1 made of amorphous (Co-Zr) or the like
1b is provided. Furthermore, this first yoke 11b
A permalloy plating film 12 is formed on the upper surface of the. As described above, the second yoke 4, the first yoke 11b, the magnetic ferrite substrate 1 insulating layer 25, and the coil 7 constitute the thin film magnetic head 200 for recording. Further, the closed magnetic circuit of the above-mentioned second yoke 4 → first yoke 11b and the magnetic ferrite substrate 1 is formed.

The magnetic ferrite substrate 1 is filled with a non-magnetic material such as glass to prevent magnetic flux leakage between the second yoke 4 and the magnetic ferrite substrate 1 and to prevent deterioration of magnetic efficiency. It has a magnetic layer 2. The non-magnetic layer 2 is filled with a non-magnetic material inside a groove 1a whose inner surface is perpendicular to the main surface of the ferrite substrate 1 and whose bottom surface is parallel to the main surface of the ferrite substrate 1. .

The depth h of the nonmagnetic layer 2 from the main surface of the ferrite substrate 1 is set within the range of 15 μm to 50 μm, and the inner side surface and the bottom surface of the groove 1a have a radius of 10 μm ( They are continuously connected by the following arcs R in the figure.

On the other hand, a passivation film 13 is formed on the upper surfaces of the third yoke 3 and the permalloy plating film 12, and a protective plate 14 is adhered on the passivation film 12 with an epoxy adhesive. There is. With the above configuration, a thin film magnetic head having the reproducing thin film magnetic head 100 and the recording thin film magnetic head 200 is constituted.

Next, a manufacturing process of the composite type thin film magnetic head having the above structure will be described with reference to FIGS. 3 to 5 are sectional views corresponding to the section of FIG.

First, on the ferrite substrate 1, the width (W) is 1
A groove 1a having a depth (h) of 40 μm and a range of 95 to 130 μm is formed. At this time, the inner surface of the groove 1a is formed so as to be perpendicular to the main surface of the ferrite substrate 1, and a blade is selected such that the angle between the inner surface and the bottom surface is 10 μm or less.

Next, referring to FIG. 4, inside the groove 1a,
Insert the non-magnetic material 2 such as glass from the bottom of the groove 1a by 80 to 11
Fill up to a height of about 5 μm.

Next, referring to FIG. 5, thereafter, the ferrite substrate 1 and the non-magnetic material 2 filled in the groove 1a are simultaneously polished by about 80 μm so that the depth of the groove becomes 15 to 50 μm. Do.

After that, on the main surface of the ferrite substrate 1, Al which will be the gap of the recording thin-film magnetic head 200 is formed.
An insulating film 3 made of ₂ O ₃ or SiO ₂ and having a predetermined shape is formed. Next, a magnetic material such as FeAlSi is formed in a predetermined shape on the insulating film 3 to form the second yoke 4 of the reproducing thin film magnetic head 100. After that, SiO
_{For the} head of the thin film magnetic head 200 for recording and the bias lead 6 of the thin film magnetic head for reproduction made of Al, Al-Cu, Al-Si, etc., in which a plurality of insulating layers 5 and 25 composed of ₂ or the like are formed. The coil 7 is formed. After that, several hundred liters of permalloy or the like is formed and patterned to form the MR element 8 of the reproducing thin-film magnetic head 100.

Next, a magnetic material such as permalloy is formed on the upper surfaces of the insulating layers 5 and 25 to a thickness of about several thousand Å,
The third yoke 11a and the first yoke 11b are formed simultaneously. Then, the permalloy film 12 is formed on the upper surface of the first yoke 11b by selective plating of several μm. After that, the third yoke 11a of the reproducing thin-film magnetic head and the first underlayer 11b of the recording thin-film magnetic head that also serves as the plating base film are processed.

Next, the passivation film 13 is formed on the entire surface of the substrate so as to have a thickness of 10 to 30 μm by hiding the bonding pad portion with a metal mask or the like. After that, flattening is performed, and the protective plate 14 is bonded with an adhesive 15. After that, a plurality of heads arranged in a row in the track direction are integrally cut out from the dicing line, and cylindrical polishing and tape polishing are performed. After that, chip division is performed for each head, and a composite type thin film magnetic head including analog and digital thin film magnetic heads for recording and reproducing is completed.

The width W of the groove 1a is set to 140 μm because of the structure of the composite type thin film magnetic head, the reproducing thin film magnetic head is located in the front part and the digital part is located in the rear part of the magnetic tape as the magnetic recording medium. This is because the thin film magnetic head for recording is provided and the width of the non-magnetic portion is necessary for forming the magnetic circuit of the thin film magnetic head for recording. Next, increase the depth of the groove 1a to 15
The reason for forming within the range of up to 50 μm will be described below.

First, referring to FIG. 6, the depth of the groove 1a and
It is a figure which shows the relationship between reproduction output (V) / recording current (I). From this figure, it is understood that when the depth of the groove 1a is 15 μm or less, the value of V / I becomes small and the DCC head cannot function. Further, it is understood that when the depth of the groove 1a is 15 μm or more, V / I becomes constant and the function as a DCC head can be sufficiently fulfilled. Next, the finite element method is used by computer simulation to find out how the stress generated at the time of filling the groove 1a with the non-magnetic material acts on the ferrite substrate.
Considering the depth of a as a parameter, the result is as follows.

First, referring to FIG. 7, the depth of the groove 1a is 3
When the inside of the groove 1a is filled with a non-magnetic material with a thickness of 0 μm,
At the interface X between the cellite substrate and the non-magnetic material 2, 5.2 ×
10 ⁷The stress of Pa will be concentrated.

When the depth of the groove 1a is 50 μm, the stress concentration range X extends to the contact sliding surface 1c with the magnetic recording medium at the interface between the non-magnetic body 2 and the ferrite substrate 1, The stress value at this time is 5.3 × 10 ⁷ Pa.

Considering the results of FIGS. 7 and 8 and the transverse rupture force of the ferrite substrate of 12 × 10 ⁷ Pa, the stress generated in the ferrite substrate is about ½.
Ferrite substrates can withstand well. However, as the depth of the groove 1a becomes deeper, the stress value tends to increase and further spread to the contact sliding surface 1c.
In addition, when the composite type thin film magnetic head is actually manufactured using a substrate having a groove 1a deeper than 50 μm, as shown in FIG.
When the cylindrical grinding of c is performed, a problem that a crack C occurs on the contact sliding surface 1c occurs.

It is considered that this is because the stress generated during the filling of the non-magnetic material is added with the force during the cylindrical polishing, and therefore exceeds the transverse rupture force of the ferrite substrate. As a result, the stress at the time of filling with the non-magnetic material does not exceed the transverse rupture force of the ferrite substrate even when the stress at the time of cylindrical polishing is applied, and the stress concentration range needs to be in the contact sliding surface 1c. There is. Therefore, the depth of the groove 1c is preferably 50 μm or less. Therefore, by setting the depth of the groove 1c to 15 to 50 μm, it is possible to provide a composite type thin film magnetic head capable of stably performing cylindrical polishing or the like without lowering the magnetic efficiency and without causing cracks or the like. It will be possible. Also, FIG.
As shown in 0, since the inner surface of the groove 1c is formed perpendicularly to the main surface of the ferrite substrate 1, it is possible to process the ferrite substrate 1 and the nonmagnetic layer 2 at the same time. Even if the amounts are A, B, and C as shown in the figure, the positions of the gap depth "0", A ', B', and C ', do not change, so that the magnetic characteristic output varies. It becomes possible to provide a high performance composite type thin film magnetic head.

[0046]

According to the composite type thin film magnetic head and the method for manufacturing the same of the present invention, the side surface of the non-magnetic layer is formed so as to be perpendicular to the main surface of the ferrite substrate. Since the position of the gap depth “0” is constant regardless of the depth from the surface, it is possible to stabilize the output of magnetic characteristics.

The depth of the non-magnetic layer is 15 μm to 50 μm.
By setting m, it is possible to prevent leakage of magnetic flux from the lower yoke of the thin-film magnetic head, maintain sufficient recording characteristics, and prevent occurrence of cracks in the ferrite substrate during the manufacturing process. Therefore, it is possible to improve the yield of the composite type thin film magnetic head during the manufacturing process.

Further, by simultaneously processing the ferrite substrate and the nonmagnetic material, the main surfaces of the ferrite substrate and the nonmagnetic material layer are always aligned with each other, which adversely affects the thin film magnetic head formed on the main surface of the ferrite substrate. It is possible to form a thin-film magnetic head without using the magnetic head. Further, by continuously connecting the inner side surface and the bottom surface of the groove portion with an arc having a radius of 10 μm or less, even if there is a variation within 15 to 50 μm when the ferrite substrate and the non-magnetic material are simultaneously processed during mass production, The position of the gap depth “0” becomes constant, and it is possible to improve the yield in the manufacturing process.

[Brief description of drawings]

FIG. 1 is a plan view of a composite type thin film magnetic head according to the present invention.

FIG. 2 is a sectional structural view of a thin film magnetic head based on the present invention.

FIG. 3 is a first manufacturing process diagram of a composite type thin film magnetic head according to the present invention.

FIG. 4 is a second manufacturing process drawing of the composite thin-film magnetic head according to the present invention.

FIG. 5 is a third manufacturing process drawing of the composite type thin film magnetic head according to the present invention.

FIG. 6 is a diagram showing the relationship between the groove depth and the reproducing voltage / recording current of the composite type thin film magnetic head according to the present invention.

FIG. 7 is a first diagram showing a state of stress concentration generated in a groove portion.

FIG. 8 is a second diagram showing a state of stress concentration generated in the groove portion.

FIG. 9 is a diagram showing a state of cracks generated on a contact sliding surface.

FIG. 10 is a diagram showing a position of a gap depth “0” with respect to a polishing amount of a ferrite substrate and a non-magnetic layer.

FIG. 11 is a cross-sectional view showing the structure of a composite type thin film magnetic head in the prior art.

FIG. 12 is a first diagram showing a problem of the composite type thin film magnetic head in the prior art.

FIG. 13 is a second diagram showing a problem of the composite type thin film magnetic head in the prior art.

FIG. 14 is a third diagram showing a problem of the composite type thin film magnetic head in the prior art.

[Explanation of Codes] 1 Ferrite substrate 2 Non-magnetic layer 3 Insulating layer 4 Second yoke 5,25 Insulating layer 6 Bias lead wire 7 Head coil 8 MR element 11a Third yoke 11b First yoke 12 Permalloy plating film 13 Passivation film 14 Protective plate 100 Thin film magnetic head for reproduction 200 Thin film magnetic head for recording In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (3)

[Claims] 1. A first thin-film magnetic head having a ferrite substrate, and a first yoke which is laminated at a distance from the ferrite substrate so as to form a first gap with the ferrite substrate, A composite thin-film magnetic head in which a second thin-film magnetic head having a second yoke and a third yoke, which are stacked at a distance to form a second gap, is stacked, and the first yoke and The second yoke has at least partially the same layer, and the ferrite substrate has an inner side surface perpendicular to the main surface and a bottom surface on the main surface over a predetermined depth from the main surface. A composite thin-film magnetic head having a non-magnetic layer inside grooves that are parallel to each other. 2. The depth from the main surface of the groove is 15 μm
Is in the range of 50 μm, and the inner side surface and the bottom surface are
The composite thin film magnetic head according to claim 1, wherein the composite thin film magnetic heads are continuously connected by arcs having a radius of 10 μm or less. 3. A step of forming a groove having a depth of more than 50 μm from a main surface of a ferrite substrate, an inner side surface of which is perpendicular to the main surface, and a bottom surface of which is parallel to the main surface. And the height of the groove from the bottom surface is 50 μm inside the groove.
a step of depositing a non-magnetic material so as to exceed m, and a height from the bottom surface of the groove to the main surface of the ferrite substrate and a height to the main surface of the non-magnetic material are 15 μm to 5 μm.
0 μm, each main surface is processed at the same time, and a gap is formed between the ferrite substrate and the main surface of the ferrite substrate and the main surface of the non-magnetic material so as to form a first gap. A step of forming a first thin film magnetic head having a first yoke that is laminated with an opening, a second yoke that is laminated at an interval so as to form a second gap, and the first yoke A method of manufacturing a composite thin-film magnetic head, comprising: forming a second thin-film magnetic head having a second yoke and a third yoke that at least partially share the same layer.