JPS62222416A - Member for thin film magnetic film - Google Patents

Abstract

PURPOSE:To admit the dissidence of the thermal expansion between substrates consisting of ferrite, etc. and soft magnetic alloy film by interposing a stress relieving material consisting of the low melting glass film between the substrate an the alloy film at the time of sandwiching the soft magnetic alloy film between the 1st and 2nd substrates and forming a member for a thin film magnetic film. CONSTITUTION:The low melting glass film 6 which is the stress relieving material is interposed by a sputtering method to about 3,000Angstrom thickness between the 1st substrate 1 consisting of the ferrite or nonmagnetic material and the soft magnetic alloy film 3 consisting of 'Sendust(R)', etc., and having about 9mum film thickness at the time of depositing said alloy film on the substrate. The similar 2nd substrate 2 is provided via a protective film 4 consisting of Al2O3, etc. on the film 6 and a low melting glass film 5 similar to the film 6 is also interposed between the film 4 and the substrate 2 in this stage. The dissidence of the coefft. of thermal expansion between the substrate and the soft magnetic film is then not so much of a problem, the deterioration in magnetic characteristics is obviated and the magnetic head having high productivity and yield is obtd.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is directed to a method comprising a soft magnetic alloy film sandwiched between two substrates.
The present invention relates to a member for a thin film magnetic head.

<Prior Art> In recent years, with the diversification of information in the field of magnetic recording technology, there has been an increasing demand for increased recording density. As a method for increasing the density of magnetic recording, metal tapes with high magnetic energy or vapor-deposited tapes with low self-demagnetization are being used as magnetic tapes, and magnetic helad core materials with high saturation magnetic flux are being used. Materials with high density and high magnetic permeability are being developed. Magnetic heads that use ferrite as the magnetic head core material have been in practical use for some time, but since ferrite has a limit in saturation magnetic flux density, crystalline alloy materials or amorphous alloy materials are suitable, and these alloy films The development of thin-film magnetic heads using the core material is progressing. Thin-film magnetic heads are basically constructed by sandwiching a soft magnetic alloy film between two nonmagnetic substrates or ferrite substrates, and the thickness of the soft magnetic alloy film determines the trunk width. Therefore, the thickness of the soft magnetic alloy film must be made relatively large.

FIG. 3 schematically shows the structure of a conventional thin film magnetic head member. In the figure, 1 and 2 are nonmagnetic substrates or ferrite substrates, 3 is a soft magnetic alloy film, 4 is a protective film, and 5 is a low melting point glass film as a bonding material. Figure 4 (al, (b)
) is a process diagram showing the conventional manufacturing method of a thin film magnetic head member. First, substrates 1 and 2 with flat surfaces are prepared, and as shown in FIG. 4(a), one of the substrates 1 is Then, a soft magnetic alloy film 3 such as sendust is formed by a vapor deposition method, a spackling method, or the like. Next, as shown in Figure 4 (bl),
A protective film 4 made of SiO2 or A2203 is formed on the soft magnetic alloy film 3 by a vapor deposition method, a sputtering method, or the like.

Then, a low melting point glass film 5 is formed on the protective film 4 and the substrate 2.
These low melting point glass films are abutted against each other, and the protective film 4 and the substrate 2 are bonded together by thermocompression bonding. As a result,
A thin film magnetic head member shown in FIG. 3 in which the soft magnetic alloy film 3 is sandwiched between the substrates 1.2 is obtained.

<Problems to be Solved by the Invention> Generally, when a thin film is formed on a substrate by a vapor deposition method, a sputtering method, etc., internal stress is generated in the thin film due to the difference in thermal expansion coefficient between the substrate and the thin film. If it becomes large, the total stress of the thin film becomes large, and the amount of deflection of the phosphorus substrate on which the film is formed becomes large, or if the substrate material is a brittle material, there arises a problem that the stress concentration causes destruction of the substrate.

FIG. 5 shows the internal stress σ of the film and the total stress S of the crotch with respect to the film thickness of the soft magnetic alloy film 3 in the state shown in FIG. This is a graph showing the relationship, and shows measurement results when a soft magnetic sendust film was formed on a substrate by electron beam evaporation and then heat-treated at 600° C. in vacuum. As is clear from this graph, the internal stress σ of the film shows a constant value regardless of the film thickness, and the total stress S increases linearly with the film thickness. As already mentioned, in a thin-film magnetic head member, the thickness of the soft magnetic alloy film 3, that is, the sendust film, determines the track width, so it is necessary to increase the thickness of the sendust film to some extent. The total stress S of the film increases with the increase in the above-mentioned relationship, and the amount of deflection of the film-forming phosphorus substrate increases (as a result, the amount of deflection in the next manufacturing process, i.e., the fourth
Thermocompression bonding in the process shown in Figure (b) becomes difficult. Furthermore, when the substrate for forming the sendust film is made of a brittle material such as ferrite, the increase in total stress S causes destruction of the substrate, resulting in disadvantages such as poor productivity.

Furthermore, if strain occurs in the soft magnetic alloy film 3, there is a problem in that when it acts as a magnetic head, the magnetic properties are deteriorated due to the reverse magnetostriction effect.

The present invention aims to solve all the problems of the conventional thin film magnetic head members mentioned above at once.

<Means for Solving the Problems> The structure of the present invention will be explained with reference to FIG. 1 corresponding to the drawings of the embodiment. (For example, sendust film) On the top side of 3,
The magnetic head member provided with the second substrate 2 is characterized by interposing a low melting point glass film 6 as a stress relaxation material between the first substrate 1 and the soft magnetic alloy film 3. It will be done.

<Function> By forming the low melting point glass film 6 on the substrate 1 before forming the soft magnetic alloy film 3 on the substrate l, it is possible to form the soft magnetic alloy film 3 by vapor deposition or sputtering. The resulting internal stress in the film 3 is relaxed, and the values of the internal stress σ and the total stress S of the film 3 in the manufacturing process shown in FIG.

<Example> Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a diagram schematically showing the structure of an embodiment of the present invention.

A low melting point glass film 6 as a stress relaxation material is inserted between the first substrate 1 and the Sendust film 3, and a second low melting point glass film 5 is formed on the upper surface of the Sendust film 3 via a protective film 4. The substrate 2 is crimped.

FIGS. 2(a) and 2(b) are explanatory diagrams of the manufacturing process of this embodiment of the present invention, and an example of the manufacturing method will be described below with reference to these figures.

First, flat first and second substrates 1 and 2 made of ferrite or nonmagnetic material are prepared. Next, on the first substrate 1, a low melting point glass film 6 is formed as a stress relaxation material by sputtering, and on this low melting point glass film 6, a sendust film 3 is formed with a thickness of 9 μm by electron beam evaporation. 60 minutes in vacuum.
Heat treatment at 0°C. This state is shown in FIG. 2(a).

Here, the thickness of the low melting point glass film should be selected based on the thickness of the soft magnetic film formed thereon and the condition that foaming from the low melting point glass layer is suppressed to below a certain standard during post-process heat treatment.

Next, similar to the conventional manufacturing process, a protective film 4 such as 5i02 or /1203 is formed on the upper surface of the sendust film 3 by vapor deposition or sputtering. This state is shown in FIG. 2(b). Then, a low melting point glass film 5 is deposited on the protective film 4 and the second substrate 2 by vapor deposition or sputtering, and the low melting point glass films 5 are butted against each other and protected by thermocompression bonding. The film 4 and the second substrate 2 are bonded together to obtain the thin film magnetic head member shown in FIG.

In the above manufacturing process, the inside of the sendust film 3 is formed in the state shown in FIG. As a result of measuring the stress σ and the total stress S, they were 8.0 x 10' dyne/cIJ and 7.0, respectively.
0X10 was also dyne/cm. These values are the values during the conventional manufacturing process shown in FIG. 5, 2. I Xl09d
dyne/cnl and 1.8X10 dyne/cm
This has decreased to about 173 compared to 2017.

Due to this fact, the distortion of the member in the state shown in FIG. 2(a) is significantly reduced, and the subsequent crimping process is facilitated. In addition, when a sendust film is formed on a brittle material substrate such as ferrite, the film thickness that reaches the threshold total stress that causes substrate destruction shifts to the higher film thickness side, so the track width that can be formed is increased. It becomes possible to

<Effects of the Invention> As explained above, according to the present invention, a low melting point glass film is interposed as a stress relaxation material between a soft magnetic alloy film and a base substrate on which this film is attached. During vapor deposition or sputtering of a magnetic alloy film, the internal stress of the film is significantly relaxed, and the mismatch in thermal expansion coefficient between the substrate and the magnetic film becomes less of a problem, expanding the range of substrate selection and reducing thermal stress. Deterioration of the magnetic properties due to the inverse magnetostrictive effect is suppressed, preventing deterioration of the magnetic properties of the core, and thus improving the efficiency of the magnetic head. In addition, since the internal stress and total stress of the soft magnetic alloy film are reduced, distortion in the manufacturing process is reduced, making the subsequent manufacturing process easier, improving the productivity and yield of the magnetic head. , it becomes possible to increase the track width.

[Brief Description of the Drawings] Figure 1 is a diagram schematically showing the structure of an embodiment of the present invention, Figure 2 is an explanatory diagram of its manufacturing process, and Figure 3 is a diagram schematically showing the structure of a conventional thin film magnetic head member. FIG. 4 is an explanatory diagram of the manufacturing process, and FIG. 5 is a graph showing the correlation between the internal stress σ and total stress of the soft magnetic alloy film and the film thickness during the conventional manufacturing process. 1-First substrate 2-Second substrate 3-Sendust film 4...Protective film 5-Low melting point glass film (adhesive)

Claims (1)

[Claims] In a magnetic head member in which a second substrate is disposed on the upper surface side of a soft magnetic alloy film formed on a first substrate,
A member for a thin film magnetic head, characterized in that a low melting point glass film is interposed between the first substrate and the soft magnetic alloy film as a stress relaxation material.