JPH0580724B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a magnetic head, and particularly to a so-called composite type magnetic head in which the vicinity of the magnetic gap is formed of a ferromagnetic metal thin film. This relates to a manufacturing method.

[Summary of the invention]

In the present invention, when manufacturing a composite magnetic head in which a ferromagnetic metal thin film is provided on the abutting surfaces of the magnetic core halves, the track width regulating grooves are filled with high melting point glass in advance, and the high melting point glass is adjusted in accordance with the track width. After removing the melting point glass, a ferromagnetic metal thin film is deposited and an unnecessary portion of this ferromagnetic metal thin film is removed by surface grinding to create a magnetic core block, and these magnetic core blocks are joined using low melting point glass. By carrying out this process at a low temperature, the pseudo gap between the ferromagnetic metal thin film and the ferromagnetic oxide can be made small, and the reliability of the non-magnetic material facing the magnetic tape can be ensured.

[Conventional technology]

For example, in magnetic recording and reproducing devices such as VTRs (video tape recorders), the recording signal density is increasing, and in response to this high density recording, magnetic powders such as Fe, Co, and Ni are used as magnetic recording media. So-called metal tapes using ferromagnetic metal powder, or so-called vapor-deposited tapes in which the ferromagnetic metal material is deposited on a base film by a method such as vapor deposition, have come into use. Since this type of magnetic recording medium has a high coercive force Hc,
Head materials for magnetic heads used for recording and reproduction are also required to have high saturation magnetic flux density Bs and magnetic permeability μ. However, for example, ferrite material, which has been conventionally widely used as a magnetic head material, has a low saturation magnetic flux density Bs, and permalloy has problems in wear resistance.

On the other hand, along with the above-mentioned high-density recording, the track width of the recording track recorded on the magnetic recording medium is also becoming narrower, and in response to this, the track width of the magnetic head is also required to be extremely narrow. ing.

Therefore, conventionally, for example, as shown in FIG.
A ferromagnetic metal thin film 51 made of sendust or the like is sandwiched between non-magnetic guard materials 50, 50 made of ceramics, etc., and this thin film 51 is used to form a track and a magnetic gap g.
A magnetic head has been proposed.

Although this type of magnetic head can have a narrow track, since the magnetic path is formed only of the ferromagnetic metal thin film 51, the magnetic resistance is large, which is not desirable in terms of magnetic efficiency. Further, the ferromagnetic metal thin film 51 must be formed on the non-magnetic guard material 50 to a thickness corresponding to the track width, and since this thin film 51 is formed by a vacuum thin film forming technique such as sputtering, the film is thin. The growth rate of this thin film 5 is extremely slow.
1 needs to be formed over the entire surface of the non-magnetic guard material 50 (corresponding to the area of the head chip), which requires time to prepare a thin film and requires a large amount of ferromagnetic metal material for one magnetic head. There are problems such as: Furthermore, for the reliability of the magnetic head, the non-magnetic guard materials 50, 50 have a coefficient of thermal expansion as close as possible to that of the ferromagnetic metal thin film 51, a wear resistance at least equal to or higher than that of ferrite, and micro-pores (fine holes). There is also a problem that it is difficult to select a non-magnetic guard material 50, 50 that satisfies these requirements.

Therefore, conventionally, as shown in FIG. 16, a pair of magnetic core halves 60, 60 are formed of an oxide magnetic material such as Mn-Zn ferrite, and in order to increase the strength of the magnetic field generated from the magnetic gap g. A ferromagnetic metal thin film 62, 6 such as Sendust is formed on the magnetic gap forming surfaces of these magnetic core halves 60, 60 using a vacuum thin film forming technique such as sputtering.
2, and these pair of magnetic core halves 60, 6
A magnetic head constructed by fusion-bonding 0 with high melting point glasses 63, 63 has been proposed.

In this type of magnetic head, since the magnetic gap g is composed of a ferromagnetic metal thin film 62 having a high magnetic permeability μ, it is compatible with magnetic tapes such as metal tapes having a high coercive force Hc, and has a sufficient In addition to exhibiting excellent recording and reproducing characteristics, the magnetic tape sliding surface has excellent wear resistance. Furthermore, the magnetic head described above has the advantage that the ferromagnetic metal thin film 62 only needs to be deposited on the gap forming surface to a thickness sufficient for recording and reproducing, and the time for forming the thin film 62 can be shortened.

However, in the above magnetic head,
Since the ferromagnetic metal thin film 62, which is a different material, is adhered and formed on the ferrite core material, there are problems such as generation of pseudo gaps due to heat treatment during manufacturing and deterioration of the magnetic properties of the ferromagnetic metal thin film. There is. In particular, since this magnetic head is formed by forming a ferromagnetic metal thin film 62 and then fusion-bonding a pair of magnetic core halves 60, 60 using high melting point glass 63, each of the above-mentioned magnetic materials (ferrite and sendust) is used. is exposed to high temperatures, a diffusion reaction between ferrite and sendust tends to occur at the joint boundary parts 61, 61, and the effect of a pseudo gap at the joint boundary parts 61, 61 becomes remarkable, causing noise. etc., making it difficult to support analog recording and playback. Alternatively, it has been considered to use a glass material with a lower melting point, so-called low melting point glass, to join the magnetic core halves 60, 60, but in this case, the low melting point that is largely exposed on the tape sliding contact surface Glass reliability decreases.

[Problem that the invention seeks to solve]

In this way, in a magnetic head in which a ferromagnetic metal thin film is sandwiched between non-magnetic guard materials, it takes time to form the thin film, resulting in poor productivity and reliability problems. Therefore, in a magnetic head in which a ferromagnetic metal thin film is formed on the magnetic gap forming surface of the core half made of ferromagnetic oxide, the pseudo gap effect becomes noticeable due to heat treatment during manufacturing, making it difficult to obtain sufficient recording and reproducing characteristics. The problem is that it is difficult to obtain.

Therefore, the present invention has been proposed to solve these problems, and provides a method for manufacturing a magnetic head that efficiently manufactures a highly reliable magnetic head that does not generate pseudo gaps. The purpose is to

[Means for solving problems]

In order to achieve such an object, the method for manufacturing a magnetic head of the present invention provides track width regulating grooves on the upper surface of a substrate made of ferromagnetic oxide, and fills the track width regulating grooves to cover the upper surface of the substrate. After pouring the high melting point glass as described above, the high melting point glass on the top surface of the substrate is removed in accordance with the track width, and a ferromagnetic metal thin film is deposited over the entire top surface of the substrate. Remove unnecessary parts by surface grinding to create a pair of magnetic core blocks.
The ferromagnetic metal thin films of these magnetic core blocks are butted against each other, then bonded with low melting point glass, and then cut into a plurality of head chips.

[Effect]

As described above, in the method of manufacturing a magnetic head of the present invention, first, the upper surface of the substrate in which the track width regulating groove is formed is filled with high melting point glass, then a ferromagnetic metal thin film is deposited on the surface where the magnetic gap is formed, and then a predetermined After creating a pair of magnetic core blocks through the process,
Since the ferromagnetic metal thin films of these magnetic core blocks are butt-bonded using low-melting glass, the magnetic core blocks can be manufactured without exposing them to high temperatures after the ferromagnetic metal thin films are formed, and therefore each ferromagnetic material The diffusion reaction at the bonding boundary between the tapes is suppressed, the influence of pseudo gaps is suppressed, and the reliability of the non-magnetic material exposed on the tape sliding surface is also ensured. Further, the ferromagnetic metal thin film need only have a thickness sufficient for recording and reproducing, and may be smaller than the thickness corresponding to the track width, for example, so that the time required for forming the thin film can be shortened.

〔Example〕

Hereinafter, one embodiment of the method for manufacturing a magnetic head according to the present invention will be described in detail with reference to the drawings.

First, as shown in FIG. 1, a track width regulating groove 2 for regulating the track width is provided on the upper surface 1a of a substrate 1 made of ferromagnetic oxide such as Mn-Zn ferrite, and a predetermined track width is formed. A plurality of ferromagnetic metal thin film forming surfaces 1b are formed in parallel over the entire width of the upper surface 1a of the substrate 1, and are butted against each other. A plurality of these track width regulating grooves 2 are formed using a rotating grindstone or the like so that each section has a substantially V-shape, and are formed at predetermined intervals, a predetermined width, and a predetermined depth over the entire width of the upper surface 1a. .

Next, as shown in FIG.
It is poured at ~800°C to fill the track width regulating grooves 2 and to cover the ferromagnetic metal thin film forming surface 1b. In addition, the above-mentioned high melting point glass 4
After forming the upper surface 4a, it is desirable to surface-ground the upper surface 4a to provide a smooth surface.

Next, as shown in FIG. 3, the high melting point glass 4 formed on the ferromagnetic metal thin film forming surface 1b is removed by photoring fly technique or mechanical means. Here, the notch surface 4a of the high melting point glass 4 remaining on the substrate 1 is at a predetermined angle with the ferromagnetic metal thin film forming surface 1b, for example, the angle formed by this notch surface 4a and the ferromagnetic metal thin film forming surface 1b. but
It is preferable to form a slope so as to be inclined at an angle of 90° to 110°.

Furthermore, as shown in FIG.
A Co--Zr--Nb based ferromagnetic metal thin film 5 is deposited by sputtering. In this example,
The thickness of the thin film 5 was approximately 10 μm. Here, the material of the ferromagnetic metal thin film 5 is a ferromagnetic amorphous alloy, a so-called amorphous alloy (for example, Fe,
One or more elements of Ni, Co and one of P, C, B, Si
Al, Ge, Be, Sn, In, Mo, W, Ti,
alloy containing Mn, Cr, Zr, Hf, Nb, etc.), Fe−
Sendust alloy, which is an Al-Si alloy, Fe-Al alloy, Fe-Si alloy, Permalloy, etc. can be used, and the film deposition methods include flash deposition, vapor deposition in gas, ion plating, sputtering, etc. Vacuum thin film formation techniques such as the cluster ion beam method will be used.

Further, as shown in FIG. 5, the upper surface 5a of the ferromagnetic metal thin film 5 is ground by surface grinding using a rotary grindstone or the like to produce a core block 6. This grinding is performed until the surface of the high melting point glass 5 is exposed, so that the ferromagnetic metal thin film 5 remains only on the ferromagnetic metal thin film forming surface 1b. Here, the upper surface 6 of the obtained substrate 1
a corresponds to the magnetic gap forming surface.

As shown in FIG. 6, the high melting point glass 4 is applied to one core block 6 of the pair of core blocks 6, 6 produced by the above-described process.
Then, a groove is formed in a direction perpendicular to the ferromagnetic metal thin film 5 to provide a winding groove 7 and a core block 8.

Next, the upper surfaces 6a and 8a of the pair of core blocks 6 and 8 corresponding to the magnetic gap forming surfaces are mirror-finished. In this embodiment, the thickness of the ferromagnetic metal thin film 5 of these core blocks 6 and 8 was 5 μm.

Next, the ferromagnetic metal thin film 5 is subjected to heat treatment to adjust the magnetic properties of the thin film 5. This heat treatment is performed on the upper surfaces 6a and 8a of the core blocks 6 and 8.
in a static magnetic field perpendicular to or on this upper surface 6
The experiments were carried out at 380°C in a rotating magnetic field parallel to a and 8a.

Next, a gap spacer made of a non-magnetic material such as SiO ₂ is formed on at least one of the upper surfaces 6a and 8a of the pair of core blocks 6 and 8, that is, the magnetic gap forming surface, to a thickness that provides a predetermined gap length.

Subsequently, as shown in FIG. 7, the substrates of the pair of core blocks 6 and 8 are aligned so that the ferromagnetic metal thin films 5 and 5 deposited on the ferromagnetic metal thin film forming surface 3 are aligned with each other with high precision. These core blocks 6 and 8 are made of low melting point glass.
Bonding is done at 400℃ or less. Note that when bonding is performed at 400° C. or higher, for example, when an amorphous alloy is used as the ferromagnetic metal thin film 5, there is a problem that the amorphous alloy crystallizes. In this example, water glass was used and bonding was carried out at 150°C.

Finally, slicing was performed at the positions of the X-X line and the X'-X' line in Figure 7, and after cutting out a plurality of head chips, the magnetic tape sliding contact surface was cylindrically polished, as shown in Figure 8. The magnetic head 10 shown is completed.

The magnetic head 10 manufactured in this way is
Pseudo gaps g', g' at the boundary between the substrate 1 made of ferrite or other ferromagnetic oxide and the ferromagnetic metal thin film 5 are formed parallel to the main gap g; The playback output of the main gap was suppressed to less than -50dB compared to that of the main gap.
That is, after the ferromagnetic metal thin film 5 is deposited, there is no step of exposing the thin film 5 to high temperature.
Since the diffusion reaction between the ferromagnetic materials in the vicinity of the pseudo gaps g' and g' is suppressed, the influence of the pseudo gaps g' and g' can be reduced to a negligible level, which is sufficient for analog recording and reproduction. It will be possible to respond.

According to the experiments of the present inventors, according to the above method,
A magnetic head in which an amorphous thin film was formed on Mn--Zn ferrite, heat treated at 400°C, and then gap bonded at 200°C showed extremely good reproduction characteristics.

That is, when the frequency characteristics of the reproduced output of the magnetic head were examined, as shown by curve a in FIG. 9, almost no reduction in the reproduced output due to the pseudo gap was observed in the magnetic head. On the other hand, in a magnetic head in which a sendust alloy thin film is used as the ferromagnetic metal thin film and gap welding is performed at a temperature of 600 to 650°C, as shown by curve b in Fig. 9, the effect of the pseudo gap is Fluctuations in playback output were observed.

Further, since the magnetic tape sliding contact portion is composed of high melting point glass 4 and ferromagnetic metal thin film 5, wear resistance etc. are improved and reliability is excellent.

By the way, the present invention is not limited to the above-described embodiment, and may be a magnetic head in which high-melting point glass and a ferromagnetic metal thin film are formed only on the front gear side, for example. That is, as shown in FIG. 10, an upper surface 21 corresponding to the front gap forming surface is formed on the upper surface of the substrate 21 made of ferromagnetic oxide.
a and the upper surface 21b corresponding to the back gap forming surface.
A plurality of substantially V-shaped track width regulating grooves 22 are formed to regulate the track width only on the upper surface 21a. This board 2
1 corresponds to the substrate 1 shown in FIG. 1 in the previous embodiment. Next, with respect to the upper surface 21a of the substrate 21,
Filling process of high melting point glass 25, high melting point glass 25
The process of partially removing the ferromagnetic metal thin film 26 and the process of depositing the ferromagnetic metal thin film 26 are then carried out, and the upper surface 24a of the obtained substrate is then surface ground to form the core block 24 shown in FIG.
Make a pair. Note that each of the above-mentioned steps may be performed in the same manner as in the previous embodiment. Next, in the same manner as in the previous embodiment, the core block 24 and the core block 29 provided with the winding grooves 28 are welded together using low melting point glass, a plurality of head chips are cut out, and the tape sliding surface is shaped into a cylinder. The magnetic head 27 shown in FIG. 12 may be manufactured by polishing. Although this magnetic head 27 has a high melting point glass 25 and a ferromagnetic metal thin film 26 formed only on the front gear side, it goes without saying that it has the same effect as the previous embodiment.

Furthermore, when sendust is used for a ferromagnetic metal thin film, the thin film must be heat-treated at a temperature of 500°C or higher, which makes it impossible to ignore the effects of pseudo-gaps. In such a case, in the previous embodiment, after the step of partially removing the high melting point glass shown in FIG. 3, as shown in FIG. The kerf 31 may be formed by notching the surface in a substantially V-shape, and the ferromagnetic metal thin film 32 may be deposited on the upper surface of the substrate 30 including the inside of the kerf 31. After forming such a groove 31, the magnetic head 33 shown in FIG. 14 is manufactured through the same steps as in the previous embodiment. Magnetic head 33 thus obtained
As in the previous embodiment, no high temperature is applied during bonding, and since there is no boundary plane parallel to the main gap g, the influence of the pseudo gaps g' and g' on the reproduction output can be ignored.

〔Effect of the invention〕

As is clear from the above description, according to the method of manufacturing a magnetic head of the present invention, first, the upper surface of the substrate on which the track width regulating groove is formed is filled with high melting point glass, and then a ferromagnetic metal thin film is formed on the surface where the magnetic gap is formed. After the two magnetic core blocks are deposited and further subjected to a predetermined process to produce a pair of magnetic core blocks, the ferromagnetic metal thin films of these magnetic core blocks are butted and bonded together using low-melting glass, thereby forming a ferromagnetic metal thin film. Thereafter, there is no step of exposing the magnetic core block to high temperatures, and therefore the diffusion reaction between the ferromagnetic materials can be suppressed, and the influence of pseudo gaps can be ignored, so that a magnetic head suitable for analog recording and reproduction can be obtained.

Further, even if an amorphous alloy having excellent magnetic properties is used as the ferromagnetic metal thin film, its properties can be fully exhibited.

Furthermore, since the magnetic tape sliding contact portion is composed of a ferromagnetic metal thin film and high melting point glass, a highly reliable magnetic head with excellent wear resistance can be obtained.

On the other hand, the above-mentioned ferromagnetic metal thin film only needs to have a thickness sufficient for recording and reproduction, and for example, the thickness can be smaller than the thickness corresponding to the track width, so the formation time of this thin film can be significantly shortened. , productivity can be improved.

[Brief explanation of drawings]

1 to 8 are schematic perspective views showing the method of manufacturing a magnetic head according to the present invention in the order of steps, in which FIG. 1 shows the step of forming track width regulating grooves in a ferromagnetic oxide substrate; Figure 2 shows the high melting point glass filling process, Figure 3 shows the high melting point glass removal process,
Figure 4 shows the ferromagnetic metal thin film deposition process, Figure 5 shows the core block surface grinding process, Figure 6 shows the winding groove formation process, Figure 7 shows the core block bonding process, and Figure 8 shows the core block bonding process.
The figures each show the cylindrical polishing process. FIG. 9 is a characteristic diagram showing the frequency characteristics of the reproduced output of a magnetic head manufactured according to the manufacturing method of the present invention in comparison with that of a magnetic head manufactured using a conventional manufacturing method. 10 to 12 are schematic perspective views showing other embodiments of the present invention, in which FIG. 10 shows a track width regulating groove machining process for a ferromagnetic oxide substrate, and FIG. 11 shows a plane view of a core block. The grinding process and FIG. 12 respectively show the cylindrical polishing process. 13 and 14 are schematic perspective views showing still another embodiment of the present invention, in which FIG. 13 is a kerf (ferromagnetic metal thin film forming surface) processing step, and FIG. 14 is a cylindrical polishing step. It is. FIG. 15 is a schematic perspective view showing an example of a composite magnetic head, and FIG. 16 is a schematic perspective view showing another example of a composite magnetic head. 1... Board, 2... Track width regulating groove, 4...
High melting point glass, 5...Ferromagnetic metal thin film, 6,8...
core block.

Claims (1)

[Scope of Claims] 1. Track width regulating grooves are provided on the upper surface of a substrate made of ferromagnetic oxide, and after pouring high melting point glass to fill the track width regulating grooves and covering the upper surface of the substrate, a track width regulating groove is formed that corresponds to the track width. Then, the high melting point glass on the upper surface of the substrate is removed, a ferromagnetic metal thin film is deposited over the entire upper surface of the substrate, and unnecessary portions of the ferromagnetic metal thin film are removed by surface grinding to form a pair of magnetic core blocks. 1. A method for manufacturing a magnetic head, characterized in that the ferromagnetic metal thin films of these magnetic core blocks are butted together, then bonded with low melting point glass, and then cut into a plurality of head chips.