JPH02122409A - Thin-film magnetic head - Google Patents

Abstract

PURPOSE:To improve the patterning accuracy of a polyimide layer and to prevent the degradation in the yield of production by forming an alkaline metal diffusion preventive layer which prevents the diffusion of the alkaline metal in a glass layer between the glass layer and the polyimide layer. CONSTITUTION:The glass layer 12 is formed in the groove formed at the prescribed point on a substrate 11 consisting of a magnetic material and the alkaline metal diffusion preventive layer 13 formed by sputtering of, for example, SiO2, is formed on the substrate 11 contg. the glass layer 12. A spiral coil 14 is formed on the alkaline metal diffusion preventive layer 13 and the polyimide layer 15 which is an insulating layer is formed on the coil 14. The etching rate of the polyimide on the substrate 11 having magnetism and the glass layer 12 is, therefore, uniformized. The patterning accuracy of the polyimide layer 15 is improved in this way and the decrease in the yield in the production of the thin-film magnetic head is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a thin film magnetic head used for magnetic recording.

(Prior Art) Magnetic heads that record and reproduce information on magnetic recording media are used in magnetic recording and reproducing devices such as magnetic disk drives, floppy disk drives, and tape recorder devices. 2. Description of the Related Art As the recording density of media increases, thin film magnetic heads based on thin film formation technology are being used, for example, as magnetic heads for perpendicular magnetic recording.

Examples of such thin film magnetic heads include the following.

FIG. 3 is a side sectional view showing a conventional thin film magnetic head.

In the figure, 1 indicates a magnetic substrate.

A groove is formed at a predetermined location on the magnetic substrate 1, and a glass layer 2 is formed in this groove. Further, a spiral coil 3 is disposed on the magnetic substrate 1 including the glass layer 2.
The coil 3 is formed with a polyimide layer 4 which is an insulating layer. Further, on the magnetic substrate 1 including the polyimide layer 4 and the glass layer 2, a magnetic layer 5 serving as a magnetic core is formed. A protective layer 6 is formed on the magnetic substrate 1 including the magnetic layer 5.

Next, a method for manufacturing the thin film magnetic head constructed as described above will be explained with reference to FIGS. 4(a) to 4(d).

First, grooves are formed at predetermined locations on the magnetic substrate 1, and after forming the glass layer 2 in these grooves, the magnetic substrate 1 including the glass layer 2 is polished (FIG. 4(a)). . Next, the fourth
As shown in Figure (b), a spiral coil 3 is formed on a magnetic substrate 1. Thereafter, as shown in FIG. 4(C), a polyimide layer 4 for insulating the coil 3 is formed.

Then, a fourth layer is placed on the magnetic substrate 1 including the polyimide layer 4.
As shown in Figure (d), after forming the magnetic layer 5 serving as the core, the protective layer 6 is formed.

Next, the procedure for forming the above-mentioned polyimide layer 4 will be explained in detail.

First, with the coil 3 formed on the magnetic substrate 1 including the glass layer 2 shown in FIG. 4(b), photosensitive or non-photosensitive polyimide is coated on the magnetic substrate 1. . Next, this polyimide is semi-cured at a temperature of about 90° C. in the case of photosensitive polyimide and about 150° C. in the case of non-photosensitive polyimide. In the case of photosensitive polyimide, after exposure, etching is performed using an alkaline developer. In the case of non-photosensitive polyimide, a photoresist is patterned on the polyimide, and then the polyimide is etched with an alkaline developer and then the photoresist is removed. After performing these treatments, the polyimide is cured at a temperature of about 350°C.

By the way, in the above-mentioned thin film magnetic head, when forming a pattern of the polyimide layer, the alkali metal in the glass diffuses into the portion of the polyimide located on the glass layer. Since alkali metals usually have the effect of promoting imidization of polyimide, the etching rate of the polyimide located on the glass layer is slower than that of the other parts. Therefore, as shown in the plan view of Figure 5,
A bend (step) B occurs at the edge of the polyimide pattern at the boundary A between the magnetic substrate 1 and the glass layer 2 due to the non-uniform etching rate, reducing the patterning accuracy of the polyimide layer 4 and reducing the thickness of the thin film. There is a problem in that the yield in manufacturing magnetic heads decreases.

(Problems to be Solved by the Invention) As mentioned above, conventional thin-film magnetic heads have a problem in that the patterning accuracy of the polyimide layer for insulating the coil decreases, and the yield in manufacturing the thin-film magnetic head decreases. be.

The present invention is intended to solve the above-mentioned conventional problems,
It is an object of the present invention to provide a thin film magnetic head that can improve the patterning accuracy of a polyimide layer for insulating a coil and effectively prevent a decrease in yield in manufacturing the thin film magnetic head.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a magnetic substrate, a glass layer formed on a part of the substrate, a coil formed on the substrate, and a coil formed on the substrate. In a thin film magnetic head, the thin film magnetic head has a polyimide layer insulating the substrate, a magnetic layer forming a magnetic core formed through a glass layer on the substrate, and a protective layer formed on the substrate including the magnetic layer. , an alkali metal diffusion prevention layer is formed between the glass layer and the polyimide layer to prevent diffusion of alkali metal in the glass layer.

The alkali metal diffusion prevention layer in the thin film magnetic head of the present invention is formed of at least one selected from 8102, Z"02, and AJ2203.

(Function) In the present invention, an alkali metal diffusion prevention layer is formed between the glass layer and the polyimide layer to prevent diffusion of alkali metal in the glass layer. The etching rate becomes uniform.

Therefore, the patterning accuracy of the polyimide layer is improved, and a decrease in yield in manufacturing the thin film magnetic head can be effectively prevented.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a side sectional view showing a thin film magnetic head according to an embodiment of the present invention.

In the figure, 11 indicates a magnetic substrate.

A groove is formed at a predetermined location on the magnetic substrate 11, and a glass layer 12 is formed in this groove.

On the magnetic substrate 11 including the glass layer 12, for example, 5
An alkali metal diffusion prevention layer 13 is formed by sputtering i02. A spiral coil 14 is formed on this alkali metal diffusion prevention layer 13, and a polyimide layer 15, which is an insulating layer, is formed on the coil 14. Further, on the magnetic substrate 11 including the polyimide layer 15 and the glass layer 12, a magnetic layer 16 serving as a magnetic core is formed. A protective layer 17 is formed on the magnetic substrate 11 including the magnetic layer 16. Note that the alkali metal diffusion prevention layer 13 may be formed of ZrO2, AJ2zOx, etc. in addition to Si20.

FIG. 2 is a plan view for explaining the action of the alkali metal diffusion prevention layer 13 described above.

As shown in the figure, on the magnetic substrate 21 and on the glass layer 2
2, an alkali metal diffusion prevention layer 23 is formed by sputtering 5i02 by about 0.1 .mu.I. A polyimide layer 24 is formed on this alkali metal diffusion prevention layer 23.

In this case, since the alkali metal diffusion prevention layer 23 prevents the alkali metal from diffusing in the glass layer 22, the polyimide etching rate can be made uniform, thereby improving the patterning accuracy of the polyimide layer. Can be done. Therefore, the yield in manufacturing the thin film magnetic head can be improved.

[Effects of the Invention] As explained above, the thin film magnetic head of the present invention has an alkali metal diffusion prevention layer formed between the glass layer and the polyimide layer to prevent the diffusion of alkali metal in the glass layer. The etching rate of the polyimide on the substrate and the glass layer becomes uniform.

Therefore, the patterning accuracy of the polyimide layer is improved, and a decrease in yield in manufacturing the thin film magnetic head can be effectively prevented.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view for explaining a thin film magnetic head according to an embodiment of the present invention, FIG. 2 is a plan view for explaining the operation of the thin film magnetic head of the present invention, and FIG. 3 is a conventional thin film magnetic head. 4(a) to 4(d) are views for explaining the manufacturing method of the thin film magnetic head of FIG. 3, and FIG. 5 is a side sectional view showing the magnetic head, and FIG. 5 is for explaining the operation of the conventional thin film magnetic head. FIG. 11... Magnetic substrate, 12... Glass layer, 13.2
3... Alkali metal diffusion prevention layer, 4... Coil, 5.24... Polyimide layer, 16... Magnetic layer, 1
7...Protective layer.

Claims (2)

[Claims] (1) A magnetic substrate, a glass layer formed on a part of this substrate, a coil formed on the substrate, a polyimide layer insulating this coil, and a glass layer on the substrate. In the thin film magnetic head, the glass layer is disposed between the glass layer and the polyimide layer. A thin film magnetic head characterized in that an alkali metal diffusion prevention layer is formed to prevent diffusion of alkali metal therein. (2) The alkali metal diffusion prevention layer is SiO_2, ZrO
2. The thin film magnetic head according to claim 1, wherein the thin film magnetic head is formed of at least one selected from the group consisting of Al_2O_3 and Al_2O_3.