JPS6182305A - Producing for magnetic head - Google Patents

Abstract

PURPOSE:To form a high-precision gap by subjecting the second layer glass to heat treatment at a prescribed temperature for a prescribed time for the purpose of discharging Ax gotten between an SiO2 film and glass films before glass films after sputtering are joined to each other. CONSTITUTION:An SiO2 film 4 and a glass film 5 are formed successively on each of ferrite cores 11 and 12 by the magnetron sputtering method. The SiO2 film is formed with 8,000Angstrom thickness and the glass film is formed with 2,000Angstrom thickness in case of 2mu gap length. These ferrite cores 11 and 12 are butted, and a reinforcing glass 6 is set, an ferrite cores 11 and 12 are heated at 850 deg.C while being press-fitted, thereby forming the gap of a magnetic head. Thus, glasses different in viscosity are used, especially, a glass having a higher viscosity at the press-fitting heating temperature than the glass film 5 is used as he reinforcing glass 6 to suppress effectively the reaction of the glass in an apex part.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement in a method for manufacturing a magnetic head, and in particular, a method for manufacturing a magnetic head that enables gap formation with high precision and high reliability. It is related to.

[Conventional technology]

As a method of forming a gap in a magnetic head, a glass material is deposited on the front gap forming surfaces of two ferrite cores by sputtering so that the total film thickness is equal to a predetermined gear tooth width, and both cores are attached to the front gap forming surface of the two ferrite cores. A method of forming a gap within the softening temperature and melting temperature range of the glass after the constituent surfaces are brought into pressure contact with each other so as to face each other through the glass layer is disclosed in Japanese Patent Publication No. 47-26.
It is disclosed in Publication No. 336. However, in this case, all the glass between the front gap forming surfaces of the two cores is softened by the heat treatment performed within the range of the softening temperature and melting temperature of the glass, resulting in uniform adhesion over the entire surface. It has the disadvantage that it is difficult to create small gap precision variations, and when a glass layer is formed by high-speed sputtering method (magnetron sputtering method, etc.), air bubbles may be generated within or on the surface of the glass layer. However, problems have arisen, such as strength problems or fragments of the magnetic recording medium entering the bubbles during use as a magnetic head, which is considered to be the cause of characteristic deterioration.

[Problem that the invention seeks to solve]

The latter problem is particularly important when manufacturing floppy disk or hard disk heads, which have wider gap lengths than video heads, from the viewpoint of productivity, and the application of high-speed sputtering is essential. Since the number of cases where air bubbles are generated in the layer or on the surface increases rapidly, the inventors believe that this is an important problem that must be solved in practice, and after repeated studies on the amount of lead, the present invention has been developed. This is what we have come to.

The present inventors have discovered that the above air bubbles are caused by Ar occluded in the glass layer during high-speed sputtering, which forms air bubbles within or on the surface of the glass layer after bonding during heat treatment for thermocompression bonding of the glass layers. We have confirmed that this is due to the above, and have come up with the present invention.

The present invention provides a method for manufacturing a magnetic head that is free from air bubbles in the gap portion after bonding and enables gap formation with high precision and high reliability.0 [Means for Solving the Problems] In the present invention, two parts constituting the gap of the magnetic head are
As the first layer, St O
As a second layer, a glass film is first formed using a high-speed sputtering method, and then heat treatment is performed to remove Ar at a temperature between the softening temperature of the second layer glass and 950°C.
After 5 minutes to 1 hour, the gap-constituting surfaces of the assembly pieces to be combined with each other are placed on top of each other, and the second layer of the two assembly pieces is assembled by heating while applying pressure. At the same time, a reinforcing glass is bonded to the opposite side of the surface facing the magnetic recording medium in the gap portion.

The film thickness ratio of St 02 film and glass film is 10:1 to 10
:4 is appropriate.

[Effect]

According to the studies of the present inventors, Ar taken into the glass film or St Ch film during high-speed sputtering is released by heating the glass film + SI O2 film.
In order to emit light to a level that is practically acceptable for a magnetic head, it is preferable to heat the second layer between the glass softening temperature of the second layer and 950° C. after sputtering and before the step of bonding the glass films together. It has been found that heating can be carried out for 15 minutes to 1 hour at a temperature between 100°C higher than the softening temperature of glass and 870°C.

The reason why the sputtered film is a composite layer of the first layer, which is an St Ox film, and the second layer, which is a glass film, is as follows.

That is, when the sputtered film is only a glass film, 4.

The glass film softens during the Ar removal heat treatment, and the film thickness uniformity is already lost before the glass film bonding heat treatment,
Since the gap length of the actual product will vary widely with respect to the target gap length after glass film bonding, 81
This is because it is necessary to have a two-layer structure of the 02 film and the glass film. In addition, by forming such a two-layer structure, the gap length is in accordance with the target value during the bonding heat treatment between the glass films, there is little variation, and the bonding strength at the gap portion is increased.

〔Example〕

Next, examples of the present invention will be described.

As shown in FIG. 1, SiOg films 4. Then, a glass film 5 is sequentially formed by magnetron sputtering. For a gap length of 2 μm, the 5i02 film is 8000A and the glass film is 200O
It was formed to a thickness of A. These ferrite cores 11, 12
85 and set the reinforced glass 6 against each other.
The gap of the magnetic head was formed by heating the ferrite cores 11 and 12 while pressing them together at 0°C. FIG. 2 shows the viscosity characteristics of the glass of the glass film 5 used for adhesion and the reinforced glass 6. By using glasses with different viscosities as described above, in particular, by using a glass with a higher viscosity than the glass film 5 at the pressure bonding heating temperature as the reinforcing glass 6, the reaction of the glass in the apex portion can be suppressed. It was effective ○ Figure 6 shows the conventional method,
In other words, the diagram after forming the gap in the apex part when the same glass is used for the glass film 5 and the reinforcing glass 6 is shown in (
Partial schematic diagrams are shown as (b) and (a) of this embodiment.

FIG. 4 shows the ratio tglass / (tglass
s + tsio2) is a diagram showing how the ratio of defective gap lengths to the target gap length depends.

A gap can be formed with little variation when tglass/tglass + tsio2 is up to about 0.4.

Figure 5 shows tglass/1g1ass + tsio
Fig. 2 shows how the gap strength depends on Fig. 2. tglass 71g1ass +
When tsio2 is about 0.1 or more, stronger gap formation can be achieved than with conventional methods.

As you can see from the above, tglass/1g1ass +
When tsio2 is in the range of 0.1 to 0.4, it is possible to form a gap that is superior to the conventional method in both precision and strength. Table 1
This is a comparison of how the difference between the optical gap length and the effective gap length is improved compared to the conventional method.
[Effects of the Invention] As explained above, according to the present invention, there is an effect that gap formation with higher strength and higher precision can be obtained with less irregularity than the conventional method.

[Brief explanation of drawings]

FIG. 1 is a gap forming process diagram according to the present invention. Figure 2 shows the viscosity properties of bonded glass and reinforced glass at 7
. FIG. 6 is a schematic diagram of the airpex part, and FIGS. 4 and 5 show the thickness of the second glass layer and the defective rate, respectively. It is a figure showing the relationship of strength. 11, 12-: Ferrite core, 4: St 0
2 membranes. 5 Ni glass film, 6: Reinforced glass. , 8. Figure l→T

Claims (1)

[Claims] 1. A SiO_2 film as a first layer and a glass film as a second layer are sequentially formed by high-speed sputtering on each of the gap-constituting surfaces of the assembly pieces that make up the gap of the magnetic head. By stacking the gap-forming surfaces of the pieces to be assembled with each other facing each other and heating while applying pressure, the glass films that are the second layer of the two assembled pieces are joined together, and the magnetic recording in the gap portion is In the case where reinforced glass is bonded to the opposite side of the surface facing the medium,
After sputtering and before the step of bonding the glass films together, release the Ar that has entered into the SiO_2 film and the glass film by sputtering for 15 minutes to 1 hour at a temperature between the softening temperature of the second layer glass and 950°C. A method of manufacturing a magnetic head, which comprises performing heat treatment. 2. The method of manufacturing a magnetic head according to claim 1, wherein the heat treatment for releasing Ar is performed at a temperature ranging from 100°C to 870°C higher than the softening temperature of the glass film. 3. The ratio of the film thickness of the first layer and the second layer is 10:1 to 10:
4. The method of manufacturing a magnetic head according to claim 1, wherein: