JPH03276405A - Production of magnetic head - Google Patents

Abstract

PURPOSE:To freshly obtain a surface layer part where internal stresses are not generated and to restore the magnetic characteristics of head chips by cutting a head block to obtain the chips, then subjecting the region inclusive of at least the cutting surface of the chips to etching of a nearly uniform depth to relieve the work strains generated with the cutting. CONSTITUTION:After the surface 10 of a ferrite wafer 11 is polished to a specu lar surface, a ferromagnetic thin film 2 consisting of 'SENDUST(R)', etc., is deposited thereon and is bored with plural grooves 21 by ion beam etching, by which the thin films 2 are formed as projecting patterns. Track width regulat ing grooves 11 are hollowed in the positions overlapping on the grooves 21 and further, coil grooves 12 and glass grooves 13 are hollowed in the direction intersecting therewith. A laminate 56 obtd. in such a manner and another lami nate 57 are superposed on each other via a gap spacer 3 and low melting glass 4 is packed into the grooves 13. Both laminates are fixed to each other to form a joint body 5. The block 51 consisting of a pair of half bodies 55 inter posed with spacers 3 is formed by machining to form a curved surface 52 to serve as a tape connecting surface thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a magnetic head installed in a rotating head cylinder of a VTR or the like.

(Prior art) In recent years, recording media with high coercive force, such as metal tapes, which are capable of recording high-density signals, have become widespread.They are suitable for recording signals on such recording media, and are also suitable for narrowing tracks. As a possible magnetic head, as shown in FIG. 11, a pair of ferromagnetic metal cores (8) and (81) made of ferromagnetic oxide are placed at the abutting part with a magnetic gap part (80) in between. A composite magnetic head in which thin films (82) and (83) are formed is known.

In manufacturing the above magnetic head, as shown in FIG. 7, a head block (51) is provided with a pair of block halves (55) (55) made of a magnetic material such as ferrite on both sides with a gap spacer (3) in between. After manufacturing, the head block (51) is cut to manufacture a head chip (53) in which the magnetic gap portion (80) is exposed on the tape contacting surface (86) as shown in FIG. The pair of head block halves (55) (55) are made of low melting point glass (4).
are fixed to each other by.

Thereafter, the head chip (53) in FIG.
A heat treatment is applied to the head block (51) at a temperature of about 10.degree.

(Problem to be Solved) However, with the cutting of the head block (51), a large processing strain is also generated in the ferrite portion, and due to this processing strain, the magnetic core portion (8) ( There was a problem in that the magnetic permeability of 81) decreased, leading to a decrease in head output.

Removal of processing strain in the ferrite portion requires heat treatment at a high temperature of 400'C or higher, for example about 600C.

However, the magnetic properties of sendust and amorphous alloys, which are the materials for the ferromagnetic metal thin film of composite magnetic heads, deteriorate when the temperature is raised to about 600°C. As mentioned above, a glass with a low softening point had to be used for joining the halves together. Therefore, the heat treatment temperature for alleviating processing strain is 400°C, which is the softening point of the bonding glass.
There was a problem in that it was not possible to raise the temperature above 30°F (about 30°F), and it was not possible to sufficiently remove machining strain, especially in the ferrite part.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a magnetic head that can sufficiently remove processing strain without using conventional heat treatment.

(Means for Solving the Problems) In the method for manufacturing a magnetic head according to the present invention, after a head block (51) is cut to produce a head chip (53), at least the cut surface A of the head chip (53) is It is characterized by etching the area including the area to a substantially uniform depth to remove processing distortion caused by cutting.

In addition to chemical etching in which the head chip (53) is immersed in a phosphoric acid solution, ion beam etching can be used for the etching.

(Functions and Effects) The processing strain that occurs when cutting the head block (51) is an internal strain that occurs at the very surface layer of the cut surface (for example, at a depth of several μm), so it can be removed by etching. By removing the surface layer, a new surface layer in which no internal stress is generated is generated, and the magnetic properties of the head chip (53) are restored.

Therefore, a magnetic head with good magnetic properties can be obtained without going through the process of removing machining strain by heat treatment as in the prior art.

(Examples) Examples are provided to explain the present invention, and should not be construed as limiting the invention described in the claims or reducing its scope.

An example in which the present invention is implemented in a method for manufacturing a composite magnetic head will be described with reference to FIGS. 1 to 11.

First, as shown in Figure 1, the surface (10
), a ferromagnetic metal thin film (2) is formed on the surface as shown in FIG. The ferromagnetic metal thin film (2) has a thickness of 50 angstroms on the wafer surface (10).
In2 film is formed, a sendust thin film with a thickness of 5 μm is formed on the surface, and a Si film with a thickness of 0.27 μm is further formed on the surface.
It has a laminated structure (not shown) in which an O2 film is formed.

As shown in FIG. 3, the ferromagnetic metal thin film (2) is grooved (21) by ion beam etching to form a protrusion pattern with a predetermined track width Tw (for example, 27 μll1).

Next, as shown in FIG. 4, a track width regulating groove (11) is formed in the wafer (1) at a position overlapping with the grooved portion (21), and further, as shown in FIG. 11)
Coil groove (12) and glass groove (1
3) (13) is recessed.

Laminated body (56) obtained through the steps shown in Figures 1 to 4
and the laminate (57) shown in FIG. 5 are stacked together with the gap spacer (3) in between as shown in FIG.
3) is filled with low melting point glass (4) and both laminates are fixed to each other to produce a bonded body (5). In this process, the track width regulating groove (11) is also filled with glass (4).

Thereafter, the joined body (5) is machined to form a herald block (51) consisting of a pair of head block halves (55) (55) with a gap spacer (3) interposed therebetween as shown in FIG. Create. The head block (51) is formed with a curved surface (52) that will eventually come into contact with the magnetic tape.

As shown in FIG. 8, a coating film (6) made of SiO2 with a thickness of about 1 μm is formed on the curved surface (52) of the head block (51) by a well-known thin film forming technique. ) to the track width regulating groove (
11) along the glass portion to obtain a plurality of head chips (53) shown in FIG. At this time, since the coating film (6) is transparent, the cutting position will not be unclear. Incidentally, grooves (54) (54) for defining the width of the tape-contacting surface are machined on the curved surface on which the coating film (6) is formed, if necessary, as shown in the figure.

A plurality of head chips (53) obtained through the above steps are passed through a wire (7) through a coil groove (12) as shown in Figure 10.
2), and to these Sodochi Tsubu (53
) is immersed in a phosphoric acid solution tank (71), and the outer surface of each RAD tip (53) is treated with the phosphoric acid solution (7). The phosphoric acid solution (7) has a concentration of about 80%, a temperature of about 40° C., and an immersion time of 10 to 30 minutes. As a result, the surface layer of the head chip (53) excluding the area where the coating film (6) is formed reacts with the phosphoric acid solution (7) and is eluted, and is removed at a depth of about 1 to 5 μm. .

Newly generated be-rad chips by etching (
53), no machining distortion occurs on the surface as in machining.

The coating film (6) is formed to prevent the glass portion and ferromagnetic metal thin film appearing on the tape contacting surface (86) of the head chip (53) from being corroded by the phosphoric acid solution (7). It's for a reason. Therefore, it is not necessarily necessary to form a coating film in a single-type magnetic head or the like in which the magnetic core is only made of ferrite.

After the above etching, the head chip (53) is thoroughly washed with water.

Finally, the surface on which the coating film (6) is formed is polished with a lapping tape or the like to remove the coating film (6) as shown in FIG. Form.

As a result, a composite magnetic head having desired magnetic properties is completed.

As the etching solution, various acids such as hydrochloric acid can be used in addition to phosphoric acid solution. Furthermore, not only chemical etching but also ion beam etching can be employed.

FIG. 12 compares the frequency characteristics of recording and reproducing outputs of a composite magnetic head manufactured by a conventional manufacturing method and a composite magnetic head manufactured by a manufacturing method according to the present invention, and shows the characteristic curve ( 9) is approximately 1 dB better than the conventional characteristic curve (91) in the high frequency range of 5 MHz or higher.

A composite magnetic head that can obtain the effects of the manufacturing method according to the present invention is shown in FIG. 11, or as shown in FIG.
8) In addition to the one in which the ferromagnetic metal thin film (82) is formed over the entire width in the thickness direction of the magnetic gap part (81), the one in which the ferromagnetic metal thin film (82) is formed only on one side of the magnetic gap part (80) as shown in FIG. As shown in Figure 14, the boundary line between the ferromagnetic metal thin film (82) (83) and the magnetic core portion (8) (81) forms the magnetic gap portion (80).
), as well as both sides of the magnetic core parts (8) and (81) as shown in Fig. 15.
82) and covered by (83).

The above description of the embodiments is for illustrating the present invention, and should not be construed to limit or reduce the scope of the invention described in the claims.

Further, it goes without saying that the configuration of each part of the present invention is not limited to the above-mentioned embodiments, and various modifications can be made within the technical scope of the claims.

For example, the method for manufacturing a magnetic head according to the present invention is effective not only for manufacturing a composite magnetic head but also for manufacturing a single magnetic head consisting only of a ferrite core. It is also possible to use heat treatment in combination.

[Brief explanation of drawings]

1 to 11 show a series of steps for manufacturing a magnetic head, FIGS. 1 to 7 are a series of steps for manufacturing a head block, and FIG. 8 is a diagram for forming a coating film. Fig. 9 is a process diagram for cutting the head block into head chips, Fig. 10 is an etching process diagram, Fig. 11 is a process diagram for forming the tape contact surface, Fig. 12 is a graph showing the head output characteristic curve, and Fig. 13 is a diagram showing the process of forming the tape contact surface. 1 to 16 are enlarged plan views showing essential parts of various composite magnetic heads. (51)...Head block (6)...Coating film (53)...Head chip (7)...Phosphoric acid solution (86)...Tape contact surface (80)...Magnetic Gap part (82) (83)...Ferromagnetic metal thin film (8) (8
0)...Magnetic core part

Claims (1)

[Claims] [1] A pair of head block halves (5
5) After producing a head block (51) by bonding and fixing (55) to each other with a non-magnetic gap spacer (3) in between, The head block (51) is cut along the cut plane A, and the surface facing the recording medium (
86) and a magnetic head manufacturing method for manufacturing a head chip (53) having a magnetic gap portion (80),
A region including at least the cut surface A of the head chip (53) is etched to a substantially uniform depth to remove processing distortion caused by cutting the head chip (53). A method of manufacturing a magnetic head.