JP2708622B2 - Thin film magnetic head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin-film magnetic head used for a magnetic recording device, and more particularly to a thin-film magnetic head suitable for stabilizing magnetic conversion characteristics.

[Conventional technology]

FIG. 5 is a cross-sectional view showing a schematic configuration of a front portion of a conventional thin-film magnetic head. The prior art will be described with reference to FIG. As shown in FIG. 5, the conventional thin-film magnetic head comprises a lower magnetic body 2 and an upper magnetic body 7 provided on a substrate 1.
The gap layer 3 and at least one conductor coil 5
And the first insulating layer 4 and the second insulating layer 6 are interposed therebetween. Although this example shows a case where the conductor coil 5 has a single layer, there is a case where the conductor coil 5 is formed in a plurality of layers.

In the thin-film magnetic head shown in FIG.
It is necessary to form the inclined region a where the second magnetic layer 6 and the second insulating layer 6 overlap with each other, thereby forming the pattern of the upper magnetic body 7 more accurately.

This is because when the inclined region a is not formed smoothly, the etching rate of the upper magnetic body 7 becomes uneven, and the upper magnetic body 7 is apt to be left unetched.
If the etching residue remains in the upper magnetic body 7, the magnetic domain structure of the upper magnetic body 7 is disturbed, and the read / write characteristics are deteriorated.

For example, Japanese Patent Publication No. 2-767 discloses the following invention as a method of forming the inclined region a gently. That is, when forming the insulating layer with a thermoset photoresist, first apply a photoresist,
After the exposure and the development, before the thermosetting, the entire surface is re-exposed.
Next, after the re-exposure, the film is cured by heating at a predetermined temperature to obtain a more gentle photoresist film (insulating layer). In Japanese Patent Publication No. 2-767, a positive type novolak resin photoresist is used. In this regard, IBM Technical Disclosure Breten Vol. 23, 2584-
2585 pages (1980) (IBM.Technical Disclosure Bul
letin Vol.23 p.2584 ^- 2585, it is described in detail in the (1980)).

[Problems to be solved by the invention]

In the above-mentioned prior art, no consideration is given to the variation in the exposure amount due to the uneven coating of the photoresist.
Therefore, since the thickness of the photoresist layer changes due to uneven coating, a relative change in the light exposure occurs in the film after exposure, and as a result, the taper angle of the insulating layer at the tip of the thin-film magnetic head is stabilized. There was a problem that it could not be controlled.

Therefore, when the upper magnetic material is formed on the insulating layer by sputtering or the like, there is a problem that the thickness of the slope portion varies, and the electromagnetic conversion characteristics of the thin-film magnetic head also vary.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems of the related art, and has as its object to provide a thin-film magnetic head that has a small variation in taper angle and has stable electromagnetic conversion characteristics.

[Means for solving the problem]

The first thin-film magnetic head of the present invention is applied to a thin-film magnetic head having a structure in which at least one conductor coil, a plurality of insulating layers, and a gap layer are sandwiched between a lower magnetic body and an upper magnetic body. In particular, at least one of the insulating layers is formed by laminating a photoresist having a different photosensitive agent concentration as compared with the other insulating layers.

Further, the second thin-film magnetic head of the present invention is applied to a thin-film magnetic head having a structure in which at least one conductor coil, a plurality of insulating layers and a gap layer are sandwiched between a lower magnetic body and an upper magnetic body. In particular, at least one of the insulating layers is formed by laminating a photoresist having a resin having a different molecular weight from other insulating layers.

[Action]

Next, the principle of the present invention will be described with reference to FIGS.

FIG. 2 shows the relationship between the concentration of the photosensitive agent in the photoresist film and the taper angle θ at the tip of the photoresist after thermal curing. Here, the taper angle θ is indicated by the angle θ in the photoresist 20 shown in FIG. As is apparent from FIG. 2, when a photoresist having a photosensitive agent concentration of 1.0 (hereinafter referred to as a relative value) is used and thermally cured at 250 ° C., the taper angle shows about 40 °. In contrast, the photosensitizer concentration was 0.8
Decreases, the taper angle decreases to about 36 °, and when the photosensitive agent concentration increases to 1.2, the taper angle θ increases to about 45 °.

As is apparent from FIG. 2, when the thermosetting temperature is kept constant, the taper angle θ of the photocured photoresist can be controlled by setting the photosensitizer concentration in the photoresist to an appropriate value.

Also, when using a photoresist having the same photosensitizer concentration and changing the thermosetting temperature, the taper θ angle after thermosetting increases as the curing temperature decreases, and the photoresist after thermosetting increases as the thermosetting temperature increases. It can be seen that the taper angle θ becomes smaller.

Accordingly, it can be seen that the taper angle of the photoresist tip after thermal curing can be controlled by the concentration of the photosensitive agent in the photoresist and the thermal curing temperature.

FIG. 4 shows the relationship between the molecular weight of the resin in the photoresist film and the taper angle at the tip of the photoresist after heat curing. As is clear from FIG. 4, when a photoresist having a molecular weight of 1.0 (hereinafter referred to as a relative value) is used and the same thermosetting temperature is used, if the molecular weight is reduced to, for example, 0.8, the taper angle becomes small. For example, when it is increased to 1.2, the taper angle is increased.

That is, when the thermosetting temperature is fixed, by selecting the molecular weight of the resin in the photoresist to an appropriate value,
This shows that the taper angle θ of the photoresist after heat curing can be controlled. In addition, as shown in FIG. 5, in the case of a photoresist using a resin having the same molecular weight, it can be seen that the taper angle decreases as the curing temperature increases, and the taper angle increases as the curing temperature decreases.

Therefore, it can be seen that the taper angle θ at the tip of the photoresist film after thermal curing can be controlled by the molecular weight of the resin in the photoresist and the thermal curing temperature.

As is clear from the principle of the present invention described above,
According to the present invention, a thin-film magnetic head whose taper angle is appropriately controlled can be obtained by thermally curing a photoresist in which the concentration of the photosensitive agent or the molecular weight of the resin is changed and using the photoresist as an insulating layer. Therefore, variation in the taper angle due to the difference in the re-exposure amount caused by the difference in film thickness can be prevented, and variation in the electromagnetic conversion characteristics of the thin-film magnetic head can be made smaller than before.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to examples shown in the accompanying drawings.

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

Example 1 First, a lower magnetic body 11 such as permalloy is formed on a substrate 10 by sputtering or plating. Then
The gap layer 12 is formed on the lower magnetic body 11. afterwards,
A photoresist is applied by spin coating or the like, and after exposure and development, it is thermally cured at a predetermined temperature (for example, 260 ° C.), thereby forming the first insulating layer 13. Here, as the photoresist, a photoresist having a photosensitive agent concentration of 1.0 shown in FIG. 3 is used. Thereafter, a first layer coil 14 is formed by forming a film of copper using a sputtering or plating method and etching the film into a predetermined shape.

Next, the step of the first layer coil 14 is eliminated, and the first layer coil is removed.
In order to maintain insulation between the layers 14, a photoresist is applied by spin coating or the like, exposed and developed, formed into a predetermined shape, and thermally cured (for example, at 260 ° C.) to form the second insulating layer 15. Here, a photoresist having a photosensitive agent concentration of 1.0 shown in FIG. 2 is used.

After that, the second coil 16 and the third insulating layer 17 are formed in the same manner as the first coil 14 and the second insulating layer 15.

Further, in order to eliminate a step between the first insulating layer 13 and the second and third insulating layers 15, 17, the first, second, and third insulating layers 13, 15,
A photoresist adjusted to have a lower concentration of the photosensitive agent than the photoresist constituting the photoresist 17 is applied by spin coating or the like, exposed and developed, formed into a predetermined shape, and then heat-cured (for example, 26
(0 ° C.) to form the fourth insulating layer 18. Here, as the photoresist for forming the fourth insulating layer, for example, a photoresist having a photosensitive agent concentration of 0.8 shown in FIG. 2 is used.

Thereafter, the upper magnetic body 19 is formed by sputtering or plating, and the thin-film magnetic head is completed.

The thin-film magnetic head formed as described above is provided with a second insulating layer by changing the photosensitizer concentration of the photoresist.
15 and the third insulating layer 17 have a large taper angle and the fourth insulating layer has a small taper angle. Therefore, a magnetically stable tapered shape can be obtained, and a thin film magnetic head having excellent electromagnetic conversion characteristics can be manufactured with a high yield.

In the above-described embodiment, the first insulating layer 13, the second insulating layer 15, and the third insulating layer 17 are formed by using a photoresist having a photosensitizer concentration of 1.0 shown in FIG. And
Further, the fourth insulating layer 18 was formed by thermosetting at 260 ° C. using a photoresist having a photosensitive agent concentration of 0.8 shown in FIG. 3, but the present invention is not limited to this. Changes are possible.

Embodiment 2 In the thin-film magnetic head shown in FIG.
The second insulating layer 15 and the third insulating layer 17 are formed of a photoresist thermally cured at a photosensitive agent concentration of 1.2 and a temperature of 250 ° C., and the fourth insulating layer is formed of a photoresist thermally cured at a photosensitive agent concentration of 1.0 and a temperature of 260 ° C. The layer 18 is formed of a photoresist which is thermoset at a photosensitizer concentration of 0.8 and a temperature of 250 ° C.

According to the second embodiment, since the fourth insulating layer 18 is formed of a photoresist having a low photosensitizer concentration, the first insulating layer
The step between the third and third and third and third insulating layers 15 and 17 can be eliminated.

According to Embodiments 1 and 2 described above, by setting the photosensitive agent concentration and the curing temperature from the relationship between the photosensitive agent concentration and the curing temperature of the photoresist and the taper angle θ shown in FIG. (Usually 30 to 50 °).

Example 3 In the thin-film magnetic head shown in FIG.
4, the second insulating layer 15 and the third insulating layer 17 have a molecular weight of 1.
The fourth insulating layer 18 is formed by thermally curing a photoresist having a molecular weight of 0.8 shown in FIG. 4 at a temperature of 260 ° C.

According to the third embodiment, since the fourth insulating layer 18 is formed of a photoresist having a small molecular weight, the first insulating layer 13 is formed.
And the step between the second and third insulating layers 15 and 17 can be eliminated.

Example 4 In the thin-film magnetic head shown in FIG.
Is formed by thermally curing a photoresist having a molecular weight of 1.0 shown in FIG. 4 at a temperature of 260 ° C., and the second insulating layer 15 and the third
The insulating layer 17 is formed by thermally curing a photoresist having a molecular weight of 1.2 shown in FIG. 4 at a temperature of 250 ° C., and the fourth insulating layer 18 is formed by coating a photoresist having a molecular weight of 0.8 shown in FIG.
It is formed by thermosetting at ℃.

According to the fourth embodiment, since the fourth insulating layer 18 is formed of a photoresist having a small molecular weight, the first insulating layer 13 is formed.
And the step between the second and third insulating layers 15 and 17 can be eliminated.

According to Examples 3 and 4, by changing the molecular weight and curing temperature of the photoresist resin, a stable tapered shape can be obtained, and a thin film magnetic head having excellent electromagnetic conversion characteristics can be manufactured at a high yield. Can be.

Further, according to Examples 3 and 4 described above, by setting the molecular weight and the curing temperature from the relationship between the molecular weight of the photoresist and the curing temperature and the taper angle θ shown in FIG. 30 to 50 °) can be formed.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, the desired taper angle can be obtained as a physical property by changing the photosensitizer density | concentration, molecular weight, and curing temperature of a photoresist, respectively, and the thin-film magnetic head of the stable shape with small variation of a taper angle is provided. can do. Thus, a thin film magnetic head having excellent electromagnetic conversion characteristics can be manufactured with a high yield.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of a front portion of a thin film magnetic head according to an embodiment of the present invention, and FIG. 2 is a graph showing a relationship between a photosensitive agent concentration in a photoresist film and a taper angle θ of a photoresist tip after thermal curing. FIG. 3 is a cross-sectional explanatory view showing the taper angle of the photoresist tip, FIG. 4 is a view showing the relationship between the molecular weight of the resin in the photoresist film and the taper angle of the photoresist tip after heat curing, and FIG. FIG. 2 is a sectional view showing a schematic configuration of a front portion of the thin film magnetic head of FIG. 10 ... substrate, 11 ... lower magnetic material, 12 ... gap layer, 13
... first insulating layer, 14 ... first layer coil, 15 ... second insulating layer, 16 ... second layer coil, 17 ... third insulating layer, 18 ... fourth insulating layer, 19 ... Upper magnetic material, 20 ... Photoresist, θ
…… Taper angle.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Eiji Ashida 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (56) References JP-A-61-246908 (JP, A) JP-A-1-251410 (JP, A) JP-A-3-156714 (JP, A)

Claims (2)

(57) [Claims] 1. A thin-film magnetic head having a structure in which at least one conductor coil, a plurality of insulating layers and a gap layer are sandwiched between a lower magnetic body and an upper magnetic body, wherein at least one of the insulating layers is A thin-film magnetic head formed by laminating a photoresist having a different photosensitizer concentration as compared with other insulating layers. 2. A thin-film magnetic head having a structure in which at least one conductor coil, a plurality of insulating layers and a gap layer are sandwiched between a lower magnetic body and an upper magnetic body, wherein at least one of the insulating layers is A thin film magnetic head formed by laminating a photoresist having a resin having a molecular weight different from that of another insulating layer.