JPH02247808A - Thin film magnetic head and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thin film magnetic head and a method for manufacturing the same, and more particularly to a thin film magnetic head having a track width formed with high precision and a method for manufacturing the same.

[Conventional technology]

As the recording density of magnetic disk devices increases, the track width of thin film magnetic heads is also becoming finer. FIG. 2 is a side sectional view showing an example of the structure of a thin film magnetic head.

A lower magnetic film 22 is formed on the substrate 21, and forms a magnetic circuit together with an upper magnetic film 23 that will be formed later. At the tip 24, the gap material 25 is connected to the magnetic film 22.
．． and 23 to form a magnetic gap, and this gap is used to read out the recording medium, and
Write. On the other hand, at the center of the magnetic core, a conductor coil 26 is provided to intersect with the magnetic circuit, and this conductor coil 26 is insulated from the magnetic films 22 and 23 by a resin insulating film 27.

The track width, which determines the recording density of a thin film magnetic head, is usually determined by the width of the upper magnetic film 23 at the head tip 24. Therefore, in order to realize a highly accurate track width dimension, it is necessary to pattern the magnetic film 23 with high accuracy of ±0.5 μm or less below the step of the resin insulating WA 27 with a height of about 10 μm. For this reason, a dry etching method is often used because the amount of etching can be easily controlled and high accuracy can be expected.In particular, an ion milling method using accelerated ions is often used6. Publication No. 37130 cites an example of a method of patterning a thin film at a stepped portion using an ion milling method using a photosensitive resin as a mask material.
This is shown in FIG. 3. As shown in FIG. 3(a), a step 32 is formed on the top of a substrate 31, and a thin film 33 to be patterned is formed on top of the step 32. Next, Figure 3 (
As shown in b), after coating the photosensitive resin film 34 and forming a pattern, the thin film 33 is etched using the ion milling method to form the desired pattern shape, as shown in FIG. I am getting .

Furthermore, Japanese Patent Application Laid-Open No. 60-37130 discloses a method for realizing patterning with higher precision than the process shown in FIG. 3, which is shown in FIG. Figure 4 (a
), after forming a structure similar to that shown in FIG. 3 (Ca), an alumina film 45 is formed on top of it. Next, as shown in FIG. 4(b), after forming a photosensitive resin film 44, as shown in FIG. 4(Q), alumina II! 6. Then, as shown in FIG. 4(d), after removing the photosensitive resin film 44, the thin film 43 is patterned by ion milling using the alumina film 45 as a mask material to form the desired shape. I am getting .

[Problem to be solved by the invention]

Among the above conventional techniques, the method shown in FIG.

The thickness of the photosensitive resin film that serves as the mask material is approximately 1 mm at the bottom of the step.
Since the thickness becomes 0 to 15 μm, a redeposition layer 35 as shown in FIG. 5 is generated during ion milling, which deteriorates the dimensional accuracy of the thin film 33 in the lower pond with a one-step difference, and makes it difficult to obtain the desired pattern shape. I couldn't get it. In addition,
FIG. 5 is a front sectional view of the thin film pattern at the bottom of the step obtained in FIG. 3(c).

In addition, in the method shown in Figure 4, the thickness of the alumina film serving as the mask material can be made as thin as approximately 2 μm, so no redeposition layer occurs, but after the width of the photosensitive resin film is transferred to the alumina film, This requires a double process of transferring a thin film and forming a pattern, resulting in a problem of poor dimensional accuracy. Specifically, in the method shown in Figure 4, the pattern accuracy is ±0.8μ.
m is the limit, and it has been difficult to obtain a highly accurate pattern of ±0.5 μm or less.

An object of the present invention is to provide a thin film magnetic head with highly accurate track width dimensions and a method for manufacturing the same.

[Means to solve the problem]

The above purpose is a process of forming a mask material for etching the upper magnetic film into a predetermined shape after depositing the upper magnetic film on a substrate with an insulating film step. The upper part of the step difference is patterned in a separate process, and the upper part of the step is made of a thin film mask material that has been patterned in advance into a predetermined shape, and the lower part of the step difference is achieved by using a thin photosensitive resin film as the mask material. Ru. That is, by reducing the thickness of the photosensitive resin film below the step, re-adhesion during etching can be prevented and high dimensional accuracy can be achieved.

First, an upper magnetic film is deposited on a substrate with an insulating film step, and then a mask thin film is deposited. Next.

After applying a photosensitive resin and forming a pattern so that the resin remains mainly at the bottom of the step, the thin masking film is etched using the photosensitive resin film pattern as a masking material. Next, after removing the photosensitive resin film, a second photosensitive resin film is carefully applied to the entire substrate, and a pattern is formed so that the resin is magnetically present mainly only at the bottom of the step. Then, the upper magnetic film is etched using both the mask thin film pattern and the second photosensitive resin film pattern thus formed as mask materials to obtain a desired pattern shape.

The mask thin film used in this process is an inorganic insulating film.

A metal film, an organic insulating film, etc. are used. Specifically, alumina, silicon dioxide, silicon nitride, aluminum nitride,
Examples include titanium oxide, titanium nitride, tantalum pentoxide, aluminum, copper, silicon, carbon, and polyimide resin. However, in order to improve the track width accuracy at the bottom of the step, which is the objective of the present invention, it is necessary to form this mask thin film pattern with high precision, so it is desirable to use a material that is easily etched under certain conditions. . That is, for example, silicon dioxide, alumina, titanium oxide, or the like, which are easily etched by fluorine plasma.

It is desirable to use carbon, polyimide resin, etc., which are easily etched by oxidizing plasma.

Also, after etching the upper magnetic film, there are two possible methods: removing the masking thin film and not removing it, but in order to shorten the manufacturing process, it is preferable not to remove the masking thin film. It is desirable that the thin film for the mask be made of a material that is stable and has excellent adhesion to the protective film formed on top6.For example, alumina is often used for the protective film of thin-film magnetic heads, so If the protective thin film is made of alumina, a magnetic head that is stable and has excellent adhesion to the protective film can be obtained.

On the other hand, the thickness of the second photosensitive resin film formed mainly at the bottom of the step is determined by ensuring the minimum thickness required as a mask material during etching in order to improve the precision of the track width.
It is desirable that it be as thin as possible. That is, in order to prevent redeposition during etching of the upper magnetic film, it is desirable that the thickness of the second photosensitive resin film is smaller than its width. Further, the second photosensitive resin film is subjected to heat treatment at 90 to 150°C.
Alternatively, stabilizing the photosensitive resin film pattern shape by curing the resin by irradiating it with deep ultraviolet light is effective for improving track width accuracy.

Another possible method is to apply the same photosensitive resin as that used for the lower part of the step as the thin film for the mask formed mainly on the upper part of the step, but in this case, in order to improve the reliability of the magnetic head, the photosensitive resin is removed after etching the upper magnetic film. The resin film must be removed, which may complicate the process and damage the insulating film of the magnetic head. Therefore, it is desirable to use a stable material such as alumina for the mask thin film.

On the other hand, if a multilayer magnetic film, which is a laminate of one or more magnetic material films and one or more non-magnetic material films, is used as the magnetic film, a magnetic coil with high high-frequency magnetic permeability can be obtained, and therefore, even higher signal output can be obtained. A thin film magnetic head can be realized 8 [Operation] By applying the above method, the upper magnetic film can be etched even under the step using a thin photosensitive resin as a mask material, thereby eliminating the generation of a re-deposition layer. .

Furthermore, since the width of the thin photosensitive resin film pattern can be directly transferred to the upper magnetic film, high dimensional accuracy can be achieved even under the step of the insulating film, and track width accuracy is improved.

On the other hand, even at the top of the step, a thin film pattern for a mask can be obtained that is thick enough to be used as a mask material during etching.
A highly accurate upper magnetic film pattern without film thinning or pattern chipping can be obtained.

Furthermore, when considering the influence that the present invention has on the magnetic characteristics of the thin film magnetic head, there is a first-order effect. That is,
In the upper magnetic film of a thin-film magnetic head, the part from the first step silver surface to the bottom of the step is an important part that affects the magnetic properties, and it is necessary to prevent complex stress from acting on this part as much as possible. . However, JP-A-60-3
Among the methods disclosed in Publication No. 7130, when the method shown in FIG. 4 is used, the alumina film for the etching mask remains on the magnetic film below the step, so complex stress is applied to the magnetic film. This may cause signal waveform distortion.

However, if the method of the present invention is used, no masking thin film will remain on the magnetic film from the first level difference silver surface to the bottom of the level difference, so no complicated stress will be applied to the magnetic film, and the above-mentioned drawbacks can be overcome. I can do it. Further, although the thin film for the mask remains on the upper part of the step, there is no problem because the stress applied to this part has little effect on the magnetic properties.

(Embodiment) An embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a side sectional view showing a method of manufacturing a thin film magnetic head to which the present invention is applied.

First, as shown in FIG. 1(a), a ceramic substrate 1
1, a lower magnetic film 12, a gap film 13, an insulating film 14
, and after forming the conductor coil 15, the upper magnetic film 16
, and an alumina film 17 was sputtered. Next, as shown in FIG. 1(b), a positive type photoresist was applied and a pattern was formed so that the photoresist 18 remained mainly only on the top of the step. Using this photoresist 18 as a mask material, the alumina film 17 was etched by ion milling using CHFa gas, and then the photoresist 18 was removed to obtain the structure shown in FIG. 1(Q). After applying the mold photoresist, Figure 1(d)
As shown in Figure 1, photoresist 1 is mainly applied only to the bottom of the step.
A pattern was formed so that No. 9 remained. At this time, for a track width of 10 μm, the thickness of the photoresist 19 at the bottom of the step was approximately 5 μm. Then, as shown in FIG. 1(e), the alumina film 17. Then, after etching the lower magnetic film 16 by ion milling using Ar gas using the photoresist 19 as a mask material, the photoresist 19 is removed using a solvent as shown in FIG. 1(f). An upper magnetic film pattern 16 having the shape was obtained. At this time,
Since the photoresist 19 used as a mask material was thin, redeposition due to ion milling did not occur. Also.

On the right side of the step in FIG. 1, that is, at the connection part between the upper magnetic film 16 and the lower magnetic film 12, the alumina film 17 is also used as a mask material at the bottom of the step, but this part does not require high dimensional accuracy. no problem.

FIG. 6 shows a track width of 10 μm using the method of the present invention.
This figure shows the variation in track width when manufacturing a thin-film magnetic head using the conventional method.

It has been found that according to the present invention, accuracy within ±0.5 μrn can be achieved.

FIG. 7 shows an example of the structure of a thin film magnetic head according to the present invention. FIG. 7 shows a side sectional view of the thin film magnetic head. In FIG. 7(a), since the masking thin film 77 does not remain on the upper magnetic film 76 at the bottom of the step of the insulating film 74, the stress applied to this part is only due to the protective film 78. There is no deterioration of magnetic properties due to complicated stress effects.

Further, FIG. 7(b) shows an example in which the upper magnetic film portion has a three-layer structure of an upper first magnetic film 70, an alumina film 71, and an upper second magnetic film 72.

In this case as well, by applying the present invention, the masking thin film 77 remains only at the top of the step, and the alumina film 71 remaining on the upper first magnetic film 70 at the bottom of the step is thin and has low stress. The same effect as in the case of FIG. 7(a) can be obtained.

Next, another embodiment representing a method of manufacturing a thin film magnetic head to which the present invention is applied will be described with reference to FIG. First, as shown in FIG. 8(a), a ceramic substrate 81
Above, a lower magnetic film 82, a gap film 83, an insulating film 84,
After forming the conductor coil 85, the upper first magnetic film 8
61, alumina film 862, and upper second magnetic film 863
was sputtered to pattern the upper second magnetic film 863. Next, as shown in FIG. 8(b), after sputtering an etching stopper film 871 and an alumina film 872, a photoresist 88 was formed mainly only on the top of the step. Next, as shown in FIG. 8(c), using the photoresist 88 as a mask material, the alumina film 872 is etched by ion milling using CHF5 gas, and then the etching stopper film is etched by ion milling using Ar gas. 871 was etched and the photoresist 88 was removed. Next, as shown in FIG. 8(d), after forming a photoresist 89 mainly only at the bottom of the step, using the alumina film 872 and the photoresist 89 as mask materials, as shown in FIG. 8(e), Alumina membrane 86
2, and the upper first magnetic film 861 was etched and the photoresist 89 was removed to obtain an upper magnetic film pattern 861 having the desired shape.

〔Effect of the invention〕

According to the present invention, when patterning the upper magnetic film of a thin-film magnetic head, a thinner photosensitive resin film than before can be applied as a mask material even under the step of the insulating film. A pattern without adhesion can be formed.

Furthermore, since it is possible to eliminate a film that applies complex stress to the upper magnetic film at the bottom of the step, an excellent thin film magnetic head with less signal waveform distortion can be obtained.

[Brief explanation of drawings]

1 and 8 are side sectional views showing a manufacturing method according to an embodiment of the present invention, FIGS. 2 and 7 are side sectional views showing the structure of a thin film magnetic head, and FIGS. 5 is a sectional side view showing the conventional manufacturing method, FIG. 5 is a sectional view showing the drawbacks of the conventional method, and FIG. 6 is a histogram comparing the effects of the present invention and the conventional method. 11... Ceramic substrate, 12... Lower magnetic film, 1
3... Gap film, 14... Insulating film, 15... Conductor coil, 16... Upper magnetic film, 17... Alumina film, 18... Photoresist, 19... Photoresist. Keisha collection 3 drawings and illustrations (b) '5' attached to Futogojiki (P''TI) Kei Muzu rate S section

Claims (1)

[Claims] 1. At least a step portion formed on a substrate, a magnetic film formed over the top, slope portion, and bottom of the step portion, and the step portion on the surface of the magnetic film. and a thin film mask material present only on the upper part of the step part and a part of the slope part of the step part. 2. The thin film magnetic head according to claim 1, wherein the magnetic film is a part of a magnetic core of an inductive magnetic head. 3. The thin film magnetic head according to claim 1 or 2, wherein the thin film mask material is silicon dioxide, alumina, titanium oxide, carbon, or polyimide resin. 4. The thin film magnetic head according to claim 2 or 3, wherein the thin film mask material is the same material as a protective film formed on its surface. 5. The thin film magnetic head according to claim 1, 2, 3 or 4, wherein the magnetic film has a laminated structure of one or more magnetic material films and one or more nonmagnetic material films. 6. A first step of forming a magnetic film on the step portion formed on the substrate; a second step of forming a thin film mask material on a portion of the step portion and the step slope portion of the surface of the magnetic film; a third step of forming a photosensitive resin pattern on a part of the lower part of the step and the slope part of the step on the surface of the magnetic film;
A method for manufacturing a thin film magnetic head, comprising a fourth step of etching the magnetic film using the thin film mask material and the photosensitive resin pattern as a mask. 7. A method of manufacturing a thin film magnetic head according to claim 6, wherein the magnetic film is a part of a magnetic core of an inductive magnetic head. 8. Claim 6 or 7, wherein the thin film mask material comprises:
A method for producing a thin film magnetic head characterized in that it is made of silicon dioxide, alumina, titanium oxide, carbon, or polyimide resin. 9. A method of manufacturing a thin film magnetic head according to claim 6, 7 or 8, comprising a fifth step of forming a protective film made of the same material as the thin film mask material on the surface of the thin film mask material. . 10. Manufacturing a thin film magnetic head according to claim 6, 7, 8 or 9, wherein the magnetic film has a laminated structure of at least one layer of the magnetic material film and at least one layer of the non-magnetic material film. Method. 11. The method of manufacturing a thin film magnetic head according to claim 6, 7, 8, 9 or 10, wherein the thickness of the photosensitive resin pattern formed in the third step is smaller than the width thereof.