JPH1049827A - Manufacture of magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a flat surface with good accuracy for the junction surface of magnetic head half bodres and enhance the junction strength of a couple of magnetic heads, by polishing the junction surface of a couple of magnetic head half bodies with a polisher having a predetermined hardness. SOLUTION: This magnetic head is formed by connecting a couple of magnetic head half bodies, each of which is formed by forming a metal magnetic layer which will become a magnetic core and a thin film coil wound around the metal magnetic layer on a non-magnetic substrate, via a magnetic gap. The junction surface of a couple of magnetic head half bodies is polished using a polisher where a ratio of the hardness of polisher and hardness of thin film coil formed at the magnetic head half body is set in the range of 0.15-0.6. Thereafter, a couple of magnetic head half bodies are joined. Thereby, junction strength of the magnetic head half bodies can be improved and the manufacturing yield of the magnetic head can be improved without isolation of a couple of magnetic head half bodies by the process conducted after joining of the magnetic head half bodies.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magnetic head in which a pair of magnetic head halves is joined.
The present invention relates to a novel method of manufacturing a magnetic head in which the joining strength between a pair of magnetic head halves is improved.

[0002]

2. Description of the Related Art In recent years, in the field of magnetic recording for data storage, such as a video cassette recorder and a hard disk device, high-density recording of information signals has been progressing.
Therefore, a magnetic head that performs recording and reproduction is required to have higher efficiency by downsizing the magnetic core and lower inductance by thinning the coil so as to achieve higher density recording.

As a magnetic head meeting such a demand, for example, as described in Japanese Patent Application Laid-Open No. 63-231713, a magnetic path composed of a metal magnetic layer is reduced and a magnetic head for driving a magnetic head is provided. A magnetic head of a type in which the above-described coil is formed using a thin film process has been proposed.

In this magnetic head, a pair of magnetic head halves each having a metal magnetic layer serving as a magnetic core and a thin-film coil wound around the metal magnetic layer formed on a non-magnetic substrate,
They are butted and joined via a magnetic gap.

At this time, if there is a step in the joining surface of the magnetic head halves, the joining strength of the pair of magnetic head halves will be weakened. Therefore, it is desired that the joining surface of the magnetic head half be sufficiently flattened.

Therefore, conventionally, before joining a pair of magnetic head halves, their joining surfaces are ground on a tin platen using a slurry in which an abrasive is dispersed in an alkaline water-soluble solvent. By doing so, mirror finishing was performed.
In this mirror finishing, the bonding surface of the magnetic head half is flattened by both the action of chemical dissolution with an alkaline water-soluble solvent and the action of physical grinding with an abrasive.

[0007]

By the way, the bonding surface of the above-mentioned half of the magnetic head is provided with a metal magnetic layer serving as a magnetic core, terminals of a thin film coil, and a low melting point filled on a non-magnetic substrate. A plurality of members such as glass are exposed.

Since these members usually have different grinding rates, it is difficult to completely flatten the entire joining surface of the magnetic head half. For example, when the above-described mirror finishing is performed, the grinding rate of the low-melting glass is extremely fast as compared with the grinding rate of the metal magnetic layer portion serving as the magnetic core and the terminal portion of the thin film coil.
A large step has occurred on the surface of the joint surface.

As described above, it is difficult to completely flatten the joint surface of the magnetic head half. Conventionally, a pair of magnetic head halves is left with a slight step remaining on the joint surface of the magnetic head half. The body was joined. For this reason, in the conventional manufacturing method, the joining strength of the pair of magnetic head halves is weak, and sufficient durability to withstand processing after joining the pair of magnetic head halves cannot be obtained. The so-called chip cracking, which caused the halves to separate, had occurred. And
At present, no specific measures have been taken against such problems.

The present invention has been proposed in view of such a conventional situation, and aims to more precisely flatten the joining surface of a magnetic head half and improve the joining strength of a pair of magnetic head halves. With the goal.

[0011]

SUMMARY OF THE INVENTION A method of manufacturing a magnetic head according to the present invention, which has been completed to achieve the above object, comprises:
A magnetic head is manufactured by joining a pair of magnetic head halves each having a metal magnetic layer serving as a magnetic core and a thin film coil wound around the metal magnetic layer formed on a non-magnetic substrate via a magnetic gap. In this case, the joining surface of the pair of magnetic head halves is ground using a polisher having a ratio of polisher hardness to the thin film coil hardness of 0.15 or more and 0.6 or less. is there.

As described above, the joining surface of the magnetic head half is ground by using a polisher having a ratio of the polisher hardness to the thin film coil hardness of 0.15 or more and 0.6 or less. It is possible to reduce the step of the joint surface and to perform flattening with high accuracy.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the following embodiments, and it goes without saying that shapes, materials, and the like can be arbitrarily changed without departing from the gist of the present invention.

First, a magnetic head manufactured by the method of manufacturing a magnetic head according to the present embodiment will be described with reference to FIGS.
This will be described with reference to FIGS. FIG. 1 is a perspective view showing the entire magnetic head 1 manufactured by the magnetic head manufacturing method according to the present embodiment, and FIG. 2 is a portion of a region C in FIG. 3 is a plan view of a portion near the magnetic gap g as viewed from the magnetic gap g side. FIG. 3 is a partial view of a portion of a region C in FIG. 1, that is, a portion of the magnetic head 1 near the magnetic gap g. It is a perspective view shown transparently.

This magnetic head 1 is a magnetic head used for a video cassette recorder or the like. As shown in FIGS. 1 to 3, a metal magnetic layer 3a serving as a magnetic core is formed on a part of a non-magnetic substrate 2a. A magnetic head half 4a in which low-melting glass 5a is filled around the metal magnetic layer 3a, and a metal magnetic layer 3b serving as a magnetic core are formed on a part of the nonmagnetic substrate 2b in the same manner. A magnetic head half 4b filled with a low melting point glass 5b around the layer 3b.

Then, the pair of magnetic head halves is arranged such that the metal magnetic layer 3a of the one magnetic head half 4a and the metal magnetic layer 3b of the other magnetic head half 4b face each other via the magnetic gap g. The bodies 4a and 4b are abutted and joined, and a magnetic core is formed by these metal magnetic layers 3a and 3b.

In the magnetic gap formed between the metal magnetic layers 3a and 3b, the metal magnetic layers 3a and 3b
The magnetic gap formed on the butting surface at the end of the recording medium sliding surface 3b, that is, the magnetic gap functioning as a recording / reproducing gap is referred to as a front gap fg. On the other hand, the magnetic gap formed on the butted surfaces at the other ends of the metal magnetic layers 3a and 3b is called a back gap bg.

As shown in FIG. 3, the magnetic head half 4a is provided with a thin-film coil 6a formed in a spiral shape so as to wind the metal magnetic layer 3a. On the half 4b, a thin-film coil 6b formed in a spiral shape so as to wind the metal magnetic layer 3b is formed. Here, the thin film coil 6a formed on one magnetic head half 6a is formed on the low melting point glass 5a filled on the non-magnetic substrate 2a, and similarly, the thin film coil 6a is formed on one magnetic head half 6b. The formed thin film coil 6b is formed on the low melting point glass 5b filled on the non-magnetic substrate 2b.

The center end of the thin film coil 6a formed on one magnetic head half 4a and the center end of the thin film coil 6b formed on the other magnetic head half 4b are: They are connected to each other when the pair of magnetic head halves 4a and 4b are abutted and joined. That is, in the magnetic head 1, the pair of magnetic head halves 4a, 4b
Is connected so that one end of a thin-film coil 6a formed on one magnetic head half 4a and one end of a thin-film coil 6b formed on the other magnetic head half 4b are connected.

The outer peripheral end of the thin-film coil 6a formed on one magnetic head half 4a and the outer peripheral end of the thin-film coil 6b formed on the other magnetic head half 4b are: As shown in FIG. 1, external connection terminals 7a and 7b are led out. These external connection terminals 7 a and 7 b are provided so as to be exposed on the side surface of the magnetic head 1. When the magnetic head 1 is used, the external connection terminals 7a and 7b are connected to an external circuit, and a recording signal is supplied to the thin film coils 6a and 6b via the external connection terminals 7a and 7b. Or a reproduction signal is extracted from the thin film coils 6a and 6b.

In this embodiment, both the thin film coils 6a, 6a are mounted on both of the pair of magnetic head halves 4a, 4b.
Although the magnetic head 1 formed with the b is taken as an example, the thin film coil may be formed on only one of the pair of magnetic head halves 4a and 4b.

Hereinafter, a method for manufacturing the magnetic head 1 having the above configuration will be described.

When manufacturing the magnetic head 1, first,
As shown in FIG. 4, a flat substrate 21 made of a nonmagnetic material such as a MnO—NiO mixed sintered material is prepared. In this embodiment, the size of the substrate 21 is about 30 m in length.
m, width about 30 mm, and thickness about 2 mm.

The material of the substrate 21 is MnO--NiO
Not limited to this, various non-magnetic materials can be used. For example, potassium titanate, calcium titanate, barium titanate, zirconium oxide, alumina, alumina titanium carbide, SiO ₂ , Zn ferrite, crystallized glass, high hardness glass and the like can be given.

Next, as shown in FIG.
In order to form an inclined surface on which a metal magnetic layer serving as a magnetic core is formed, that is, a magnetic core forming surface, a plurality of magnetic core grooves 22 are formed such that one surface in the magnetic core groove 22 becomes an inclined surface 22a. Are formed in parallel and at equal intervals.

Here, the inclination of the inclined surface 22a is 25 to 6
The angle may be about 0 degrees, but is more preferably about 35 to 50 degrees in consideration of a pseudo gap, track width accuracy, and the like.
Therefore, in the present embodiment, the magnetic core groove 22 is formed on the inclined surface 22 by using a grinding wheel having one surface formed at about 45 degrees.
a was formed to have an inclination of about 45 degrees. The magnetic core groove 22 had a depth of about 130 μm and a width of about 150 μm.

Next, the substrate 2 on which the magnetic core groove 22 is formed
6, a metal magnetic layer 23 is formed as shown in FIG.

Here, the metal magnetic layer 23 may be composed of a single metal magnetic film. However, in order to provide high sensitivity in a high-frequency region, a plurality of metal magnetic films are interposed via an insulating film. It is better to laminate them. With such a structure, the metal magnetic layer 23 is divided into a plurality of layers, so that eddy current loss is reduced, and characteristics particularly in a high frequency region are improved.

However, when the metal magnetic layer 23 has a laminated structure as described above, the thickness of the insulating film must be large enough to obtain a sufficient insulating effect, and the insulating film must not act as a pseudo gap. It needs to be as thin as possible.

Therefore, in the present embodiment, the metal magnetic layer 23 is made of a Fe—Al—Si alloy (Sendust) having a thickness of about 5 μm and an alumina insulating film having a thickness of about 0.15 μm. And were alternately laminated so that the metal magnetic films had three layers.

Here, the material of the metal magnetic film is Fe-Al
The material is not limited to the -Si alloy, but may be any material having a high saturation magnetic flux density and soft magnetic characteristics. For example, Fe-Al alloy, Fe-Ga-Si alloy,
An Fe—Si—Co alloy, a nitride-based or carbide-based soft magnetic alloy, and the like can be given. Further, the material of the insulating film is not limited to alumina, but may be, for example, SiO ₂ , SiO,
Alternatively, a mixture of these can be used.

The metal magnetic layer 23 is preferably formed by sputtering, but may be formed by a physical film forming method such as evaporation or molecular beam epitaxy (MBE).
D) is widely applicable, and furthermore, a chemical film forming method such as vapor phase growth (CVD) involving a chemical reaction can be applied.

Next, as shown in FIG.
A winding groove 24 for forming a thin-film coil so as to wind a magnetic core in a direction perpendicular to the longitudinal direction of the magnetic core groove 22 on the main surface of the substrate 21 on which the metal magnetic layer 23 is formed.
Is formed for each magnetic core. Although FIG. 7 illustrates an example in which two winding grooves 24 and two separation grooves 25 are formed, it is necessary to provide the winding grooves 24 and the separation grooves 25 by the number of thin film coil rows to be formed. When three or more thin-film coil rows are formed, the winding grooves 24 and the separation grooves 25 are formed by the number thereof.

Here, the winding groove 24 is formed by forming a slope on the front gap fg side with a grindstone having a slope of about 45 degrees.
The metal magnetic layer 23 on the front gap fg side is obliquely narrowed down toward the front gap fg. As described above, when the metal magnetic layer 23 on the front gap fg side is narrowed down toward the front gap fg, the magnetic flux is concentrated at the front gap fg, and higher recording sensitivity can be obtained. However, the shape of the winding groove 24 may be such that the metal magnetic layer 23 on the front gap fg side is narrowed down toward the front gap fg, and the angle of the slope of the winding groove 24 on the front gap fg side is The angle may not be 45 degrees, and the shape of the winding groove 24 on the front gap fg side may be an arc or a polygon.

The depth of the winding groove 24 depends on the metal magnetic layer 23.
However, if it is too deep, the magnetic path length increases, and the magnetic flux transmission efficiency decreases. Therefore, in the present embodiment, the winding groove 24 is formed to have a depth of about 20 μm from the vertex of the slope of the magnetic core groove 22. The width of the winding groove 24 is defined by the line width and the number of turns of the thin film coil because the thin film coil is formed so as to pass through the winding groove 24 in a later step. In the present embodiment, the width of the winding groove 24 is about 140 μm.

On the other hand, the separation groove 25 may have any shape as long as it is a groove having a depth enough to completely separate the metal magnetic layer 23. Therefore, in the present embodiment, the separation groove 25 is a rectangular groove that is easy to process, and is formed to a depth of about 150 μm from the bottom surface of the magnetic core groove 22. Further, the width of the separation groove 25 is determined by a balance between the desired length of the front gap fg and the length of the back gap bg of the magnetic head. However, the length of the front gap fg is determined by the step of forming the separation groove 25 in order to finally wrap the sliding surface of the recording medium when the magnetic head is processed into a predetermined shape. It is necessary to set it longer than the length of fg. In this embodiment, the length of the metal magnetic layer 23 on the front gap fg side at the stage when the separation groove 25 is formed is about 300 μm,
The separation groove 25 was formed such that the length on the back gap bg side was about 85 μm.

Next, as shown in FIG.
2. Fill the winding groove 24 and the separation groove 25 with the molten low-melting glass 26, and then flatten the surface.

Subsequently, a thin-film coil is formed for each magnetic core on the low-melting glass 26 so as to pass through the winding groove 24, ie, to wind the metal magnetic layer 23, by a thin-film forming process.

As shown in FIG. 9, the thin-film coils 27a, 27
7b is a front gap fg of the metal magnetic layer 23.
Are formed spirally around the portion 23bg corresponding to the back gap bg so as to pass between the portion 23fg corresponding to the back gap bg and the portion 23bg corresponding to the back gap bg. Although FIG. 9 shows a pair of thin-film coils 27a and 27b corresponding to a pair of magnetic core halves to be joined, actually, the magnetic core is placed on the low melting point glass 26 filled on the substrate 21. Many thin film coils are formed each time.

Here, the thin film coils 27a and 27b are configured such that when a pair of magnetic core halves are joined to form a magnetic head, the external connection terminals derived from the thin film coils 27a and 27b are exposed to the outside. Then, the pattern of the terminal portion 28a of the thin-film coil 27a corresponding to one magnetic core half and the pattern of the terminal portion 28b of the thin-film coil 27b corresponding to the other magnetic core half are changed.

In forming such a thin-film coil, first, a portion where the thin-film coil is to be formed is etched on the low-melting glass 26 to form a recess having a depth of about 4 μm. At this time, the portion where the terminal of the thin-film coil is formed and the portion where the metal magnetic layer 23 is exposed are left without being etched and have a convex shape.

Next, a conductive base film made of Cu is formed on the entire surface, and then a photoresist is patterned on the conductive base film into a predetermined thin film coil shape. Then, after patterning the photoresist, Cu plating is grown on the conductive base film by using an electrolytic plating apparatus to form a thin film coil having a thickness of about 3 μm. Thereafter, the conductive base film remaining between the coils and excess Cu plating grown on portions other than the predetermined thin-film coil portions are removed by a technique such as ion etching. In the present embodiment,
Although the thin film coil is formed by the electrolytic plating method, it is needless to say that the thin film coil may be formed by using a technique such as sputtering or vapor deposition.

Next, when a pair of magnetic core halves are joined to form a magnetic head, the pair of magnetic core halves are joined so that external connection terminals derived from the thin film coil are exposed to the outside. Then, a part of the low-melting glass 26 facing the external connection terminal is removed.

Next, as shown in FIGS. 10, 11 and 12, a thin film coil 27 formed on a low melting glass 26 is formed.
Protective film 29 made of Al ₂ O ₃
Is formed by sputtering or the like.

Here, FIG. 10 shows one thin film coil 27.
FIG. 4 is a plan view of a portion where is formed, showing a state where a protective film 29 is formed on the entire surface. Also, FIG.
0, that is, the cross section along the line A1-A2, that is, the metal magnetic layer 2
3 is a diagram showing a cross section of a portion where a portion 23bg corresponding to the back gap bg of FIG. 3 is formed, and FIG.
0, that is, the cross section along the line A3-A4, that is, the thin film coil 2
FIG. 7 is a diagram showing a cross section of a portion where a terminal on the center side of No. 7 is formed.

Next, the surface on which the protective film 29 is formed is mirror-finished to remove the extra protective film 29 and flatten the surface as shown in FIGS. 13, 14 and 15. . Here, FIG. 13 shows one thin film coil 27.
13 is a plan view of a portion where the protective film 29 is formed, and a hatched portion in FIG. Also, FIG.
FIG. 15 is a diagram showing a cross section taken along line A5-A6 in FIG. 13, that is, a cross section of a portion where a portion 23bg corresponding to the back gap bg of the metal magnetic layer 23 is formed.
FIG. 14 is a diagram illustrating a cross section taken along line A7-A8 of FIG. 13, that is, a cross section of a portion where a terminal on the center side of the thin-film coil 27 is formed.

Here, since the surface to be mirror-finished is a joining surface of a pair of magnetic head halves, it is necessary to flatten it with sufficient precision. Specifically, in the magnetic head as in the present embodiment, if the step on this surface exceeds 35 nm, the joining strength when joining a pair of magnetic head halves becomes extremely weak, and Chip cracking is likely to occur in the post-processing.

Therefore, in this 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 protective film 29 was formed. Since Brinell hardness H _B of the metal magnetic layer 23 and the thin film coil 27 is about 80, the hardness ratio of the polisher against the hardness of the metal magnetic layer 23 and the thin film coil 27 as a workpiece is approximately 0.25 It is.

[0049] Polishing is a process in which 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 in which the surface of the workpiece is ground by rotating while being pressed 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 metal magnetic layer 2 which is the workpiece
3 and the ratio of the hardness to the hardness of the thin film coil 27 is about 0.2.
By performing mirror finishing using the polisher No. 5, the level difference of the mirror-finished surface was 25 nm or less at the maximum, and a sufficiently smooth plane was obtained. Moreover, when the polishing is performed with the ratio of the hardness of the polisher to the hardness of the metal magnetic layer 23 and the thin-film coil 27 as the workpiece being about 0.25, a sufficient grinding rate can be obtained, and mirror polishing can be performed in a short time. did it.

In the polishing, the polisher side is also ground to some extent by the abrasive.
Polishers also have a life span. However, in the present embodiment, there was no possibility that the polisher was immediately ground and became unusable, and the polisher could be used repeatedly.

By the above steps, as shown in FIG.
A plurality of thin-film coils 27 corresponding to the respective metal magnetic layers 23 separated by the separation grooves 25 are formed on the low-melting glass 26, and the magnetic head block substrate 40 whose surface is sufficiently flattened is completed.

Next, an Au thin film is formed on the surface of the magnetic head block substrate 40, and thereafter, a portion which becomes the front gap fg on the metal magnetic layer 23 and a portion which becomes the back gap bg on the metal magnetic layer 23. Then, a resist mask is formed on the center end of the thin film coil 27 and on the outside of the thin film coil 27, and the Au thin film is etched using the resist mask as a mask by a method such as ion milling.

As a result, the front gap fg on the metal magnetic layer 23, the back gap gb on the metal magnetic layer 23, the center end of the thin-film coil 27, An Au thin film is formed on the outside.

These Au thin films are for joining a pair of magnetic head block halves obtained by cutting the magnetic head block substrate 40 in a later step by Au diffusion bonding. Also, the thin film coil 27
When the pair of magnetic head block halves is joined, the Au thin film formed on the central end of the thin film coil 27 formed on one of the magnetic head block halves, It also functions as a connection conductor for electrically connecting the thin-film coil 27 formed on the other half of the magnetic head block to the end on the center side. Further, the metal magnetic layer 23
The Au thin film formed in the upper part to be the front gap fg and the part to be the back gap gb is composed of the metal magnetic layer 23 of one half of the magnetic head block and the metal magnetic layer 23 of the other half of the magnetic head block. It also functions as a gap material for forming a magnetic gap between them.

Next, as shown in FIG. 17, the magnetic head block substrate 40 is cut into a pair of magnetic head block halves 41 and 42. At this time, a thin-film coil row, that is, a plurality of thin-film coils 27 arranged in a line in the longitudinal direction is embedded in one magnetic head block half 41,
Similarly, a thin film coil array, that is, a plurality of thin film coils 27 arranged in a line in the longitudinal direction are embedded in the other magnetic head block half 42.

Next, as shown in FIG. 18, the pair of magnetic head block halves 41 and 42 are pressed against each other, and the temperature is raised.
The magnetic head block 43 is joined by diffusion bonding using an Au thin film. The temperature at which the diffusion bonding is performed is set to a temperature at which the low-melting glass 26 does not melt.

Here, a pair of magnetic head block halves 4
1, 42 are a pair of magnetic head block halves 41, 42.
Are bonded so that the respective metal magnetic layers 23 formed on each other face each other via the Au thin film. Thus, a front gap fg and a back gap bg are formed between the metal magnetic layer 23 of one magnetic head block half 41 and the metal magnetic layer 23 of the other magnetic head block half 42.

A pair of magnetic head block halves 4
Reference numerals 1 and 42 denote A formed on the center-side end of the thin-film coil 27 formed on one magnetic head block half 41.
u thin film and Au formed on the center-side end of the thin film coil 27 formed on the other magnetic head block half 42.
Join so that the thin film contacts. Thereby, the thin film coil 2 formed on one magnetic head block half 41 is formed.
7 and the thin-film coil 27 formed on the other magnetic head block half 41 are electrically connected.

In the present embodiment, the pair of magnetic head block halves 41 and 42 are joined by diffusion joining using an Au thin film, but this joining is carried out by a chemical joining method using an adhesive or the like. May be used.

Finally, a pair of magnetic head block halves 4
The magnetic head block 43 to which the magnetic heads 1 and 42 have been joined is subjected to slicing and cutting for each magnetic core, and then ground to a predetermined shape, whereby the magnetic head block 43 shown in FIG. The head is completed. Here, the pair of magnetic head block halves 41 and 42 are joined after their joining surfaces are sufficiently flattened by the above-described polishing, so that the pair of magnetic head block halves 41 and 42 are joined. Even if the magnetic head block 43 subjected to slicing is cut for each magnetic core, or if each of the cut chips is subjected to grinding processing, the processing can be performed favorably without chip breakage. It can be carried out.

In the above-described method of manufacturing a magnetic head,
The magnetic head block substrate 40 is cut for each thin-film coil row to form a pair of magnetic head block halves 41 and 42, and after joining the pair of magnetic head block halves 41 and 42, one for each magnetic core. Although the individual magnetic heads were cut one by one, the order of these cutting and joining steps can be changed. That is, for example, the magnetic head block substrate 40 may be cut in advance one by one for each magnetic core to form a magnetic head half, and the magnetic head halves may be joined to form individual magnetic heads. Good. Alternatively, for example, two magnetic head block substrates 40 may be prepared, joined together, and then cut one by one for each magnetic core to form individual magnetic heads.

Next, the relationship between the hardness of the polisher when performing mirror finishing by polishing and the hardness of the workpiece will be described.

Here, the workpiece is a magnetic head block substrate as described above. The surface to be mirror-finished is a surface to be a joining surface of a pair of magnetic head halves, a metal magnetic layer to be a magnetic core, a terminal portion of a thin film coil,
Low melting glass filled on a non-magnetic substrate is exposed.

In such a workpiece, the low-melting glass portion is easily ground, and the metal magnetic layer and the terminal portion of the thin-film coil are hard to be ground. A step is generated between the glass part and the terminal part of the metal magnetic layer or the thin film coil.
As described above, this step is required to be about 35 n in order to sufficiently secure the bonding strength between the pair of magnetic head halves.
m or less.

The size of the step changes depending on the ratio of the polisher hardness to the workpiece hardness as shown in FIG. Here, FIG. 19 shows the relationship between the ratio of the polisher hardness to the workpiece hardness and the step generated on the processed surface after polishing. Also,
FIG. 19 also shows the relationship between the ratio of the polisher hardness to the workpiece hardness and the grinding rate during polishing.

As can be seen from FIG. 19, when the ratio of the polisher hardness to the workpiece hardness increases, that is, when a hard polisher is used,
Although the grinding rate is increased and the grinding can be performed at high speed, the step generated on the processed surface after polishing becomes large. This is because if the hardness of the polisher is too high, the erosion of the abrasive into the polisher is reduced, and the flattening effect by the polishing is reduced.

This step is, as described above, 35 degrees.
It is preferable to suppress the thickness to about nm or less. Therefore, as can be seen from FIG. 19, the ratio of the polisher hardness to the workpiece hardness is preferably about 0.6 or less.

Conversely, if the ratio of the polisher hardness to the workpiece hardness is less than 0.15, the roles of the polisher and the workpiece are reversed, and the polisher side is mainly ground. . This happens when,
The grinding of the workpiece does not proceed, and the grinding rate of the workpiece is extremely reduced. In addition, since the side of the polisher is mainly ground, there is also a problem that the life of the polisher becomes extremely short. Furthermore, the scraps of the surface plate material generated by grinding the polisher adhere to the surface of the workpiece and serve as spacers, making it impossible to eliminate a step on the surface of the workpiece. Therefore, the ratio of the polisher hardness to the workpiece hardness needs to be about 0.15 or more.

As described above, when the joint surface of the pair of magnetic head halves is mirror-finished, the ratio of the hardness of the polisher to the hardness of the thin film coil is set to 0.15 or more and 0.6 or less. It is preferable to use a suitable polisher, and if it is out of this range, it becomes impossible to flatten the joint surface sufficiently accurately.

Specifically, for example, when a tin platen is used for polishing, the tin plate has a Brinell hardness H _B of 10
Or less, because Brinell hardness of the workpiece is H _B is about 80, the ratio of the polisher hardness relative to the workpiece hardness is about 0.1. Then, when the workpiece was actually ground using such a tin surface plate, the role of the surface plate and the workpiece was reversed, and good grinding could not be performed.

[0072] In contrast, for example, as in the embodiments described above, when using a polisher Brinell hardness H _B consists of about 20 Sn-Sb, the ratio of polisher hardness relative to the workpiece hardness It is about 0.25. Then, when the workpiece is actually ground using such a Sn-Sb surface plate, the surface can be satisfactorily ground without occurrence of a role reversal phenomenon between the surface plate and the workpiece, and the step difference can be obtained. And a sufficiently smooth flat surface with few defects was able to be formed.

[0073]

As is apparent from the above description, according to the present invention, the step of the joining surface of the magnetic head halves can be reduced and flattened with high precision. Strength can be improved. Therefore,
By processing after joining a pair of magnetic head halves,
The pair of magnetic head halves does not separate from each other, and the yield in manufacturing the magnetic head can be improved.

Further, in the present invention, it is possible to obtain a sufficient grinding rate at the time of grinding the joining surface of the magnetic head half and extend the life of the polisher used for grinding the joining surface of the magnetic head half. Can also.

[Brief description of the drawings]

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

FIG. 2 is an enlarged plan view showing the vicinity of a magnetic gap of the magnetic head shown in FIG. 1;

FIG. 3 is an enlarged perspective view showing the vicinity of a magnetic gap of the magnetic head shown in FIG. 1;

FIG. 4 is a perspective view schematically showing a flat substrate made of a nonmagnetic material.

FIG. 5 is a perspective view schematically showing a state where a magnetic core groove is formed in a substrate.

FIG. 6 is a perspective view schematically showing a state in which a metal magnetic layer is formed on a substrate.

FIG. 7 is a perspective view schematically showing a state in which a winding groove and a separation groove are formed on a substrate on which a metal magnetic layer is formed.

FIG. 8 is a perspective view schematically showing a state in which a low melting point glass is filled in a magnetic core groove, a winding groove, and a separation groove.

FIG. 9 is a plan view schematically showing a thin film coil formed on a low melting point glass.

FIG. 10 is a plan view schematically showing a state in which a protective film is formed on a thin film coil.

11 is a cross-sectional view schematically showing a cross section taken along line A1-A2 in FIG.

12 is a cross-sectional view schematically showing a cross section taken along line A3-A4 in FIG.

FIG. 13 is a plan view schematically showing a state where mirror protection has been applied after forming a protective film on the thin film coil.

14 is a cross-sectional view schematically showing a cross section taken along line A5-A6 of FIG.

FIG. 15 is a cross-sectional view schematically showing a cross section taken along line A7-A8 of FIG.

FIG. 16 is a perspective view schematically showing a magnetic head block substrate on which a plurality of thin film coils are formed.

FIG. 17 is a perspective view schematically showing a pair of magnetic head block halves obtained by cutting the magnetic head block substrate.

FIG. 18 is a perspective view schematically showing a magnetic head block to which a pair of magnetic head block halves are joined.

FIG. 19 is a diagram showing the relationship between the ratio of the polisher hardness to the workpiece hardness, the step after polishing, and the grinding rate during polishing.

[Explanation of symbols]

1 magnetic head, 2a, 2b non-magnetic substrate, 3a,
3b metal magnetic layer, 4a, 4b magnetic head half, 5
a, 5b low melting point glass, 6a, 6b thin film coil,
7a, 7b External connection terminal, g Magnetic gap

Claims (3)

[Claims] 1. A pair of magnetic head halves each having a metal magnetic layer serving as a magnetic core and a thin-film coil wound on the metal magnetic layer formed on a non-magnetic substrate are joined via a magnetic gap. When the magnetic head is manufactured by using a polisher having a ratio of the polisher hardness to the thin film coil hardness of 0.15 or more and 0.6 or less, the joining surface of the pair of magnetic head halves is ground. A method for manufacturing a magnetic head. 2. The pair of magnetic head halves are connected such that one end of a thin film coil formed on one magnetic head half is connected to one end of a thin film coil formed on the other magnetic head half. 2. The method for manufacturing a magnetic head according to claim 1, wherein the magnetic head is joined. 3. The magnetic head according to claim 1, wherein a low-melting glass is filled on a nonmagnetic substrate before the thin-film coil is formed, and the thin-film coil is formed on the low-melting glass. Manufacturing method.