JPH06236515A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To inhibit the occurrence of difference in the level of an insulator layer at the time of patterning a magnetic substance layer formed on the insulator layer and to avoid the breaking of a coil formed on the insulator layer. CONSTITUTION:A 1st insulator layer formed on a substrate 1 has a two-layered structure consisting of an upper layer 13 and a lower layer 12. A 1st magnetic substance layer, a 2nd insulator layer and a conductor layer are successively formed on the 1st insulator layer. A 3rd insulator layer consisting of an upper layer and a lower layer is then formed on the conductor layer and a 2nd magnetic substance layer is further formed on the 3rd insulator layer. The upper layer 13 is a tantalum pentoxide film and the lower layer 12 is a silicon oxide film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head for recording and reproducing a signal on a magnetic recording medium, and more particularly to a thin film magnetic head manufactured by a thin film forming technique.

[0002]

2. Description of the Related Art FIG. 2 is a vertical sectional view showing the structure of a conventional thin film magnetic head.

An insulating layer 2 is formed on a substrate 1, and a magnetic layer 3 is formed on the insulating layer 2 in a predetermined pattern. An insulator layer 4 is formed on the magnetic layer 3, and a conductive layer 5 is spirally formed on the insulator layer 4. The conductive layer 5 forms a coil. There is.

The conductive layer 5 is covered with an insulating layer 6, and a magnetic layer 7 is selectively formed on the insulating layer 6. A part of the magnetic layer 7 is in contact with the magnetic layer 3, and is separated from the magnetic layer 3 by a predetermined distance via the insulating layer 4 at the head tip portion. Further, the region on the substrate 1 including the regions on the magnetic layer 7 and the conductive layer 5 is covered with the insulating layer 8.

Fe (iron) -MN having a large saturation magnetic flux density
When a (nitrogen) alloy film is used for a magnetic layer of a thin film magnetic head, recording on a magnetic medium having a high coercive force becomes possible, and it is considered as a promising head for high density recording. However, M is at least one element selected from the group consisting of Ta (tantalum), Nb (niobium), Zr (zirconium), and Hf (hafnium).

In the thin-film magnetic head having the above structure, when a signal is supplied to the coil (conductive layer 5) while moving the magnetic recording medium (for example, a magnetic disk) relative to the head, the magnetic property is generated at the head tip. A magnetic field corresponding to the signal is generated between the body layers 3 and 7, and data is recorded on the magnetic recording medium.

Further, when the magnetic recording medium on which data is recorded is moved relative to the tip of the head, a magnetic field from this magnetic recording medium causes a current corresponding to the data to be generated in the coil. Data can be reproduced by electrically processing this current.

In this conventional thin film magnetic head, as shown in FIG. 2, a first insulator layer 2 and a third insulator layer 6 are provided.
Is composed of a single-layer silicon oxide film. in this way,
The reason why the insulator layers 2 and 6 are formed of silicon oxide films is as follows. Generally, in the thin film magnetic head, the second
It is preferable in terms of reproducing characteristics that the surface of the magnetic layer 7 is as flat as possible. However, the upper surface of the third insulator layer 6 has an uneven shape due to the conductor layer 5 existing therebelow. The uneven shape of the surface of the insulator layer 6 is shown in FIG.

Since the insulating layer 6 has irregularities, it is generally flattened by utilizing the constant rate etching of the resist and the insulating layer in the steps shown in FIGS. 4 (b) to 4 (d). Apply processing. In this flattening process, first, as shown in FIG.
As shown in (b), a resist 9 is applied on the insulating layer 6 having an uneven shape. The surface of the resist 9 has a flat shape due to surface tension.

FIG. 3 is a graph showing the relationship between the beam incident angle of the resist, the silicon oxide film, and the tantalum pentoxide film and the etching rate, with the horizontal axis representing the beam incident angle θ and the vertical axis representing the etching rate. is there. The resist and the silicon oxide film shown in FIG. 3 are etched at the same beam incidence angle so that the resist and the silicon oxide film are etched at a constant rate. As a result, as shown in FIG. 4C, the resist 9 and the third insulator layer 6 made of silicon oxide are etched while holding the flat surface.

When etching is continued until the resist 9 disappears, the surface of the third insulator layer 6 made of silicon oxide is flattened, as shown in FIG. 4 (d). In this way, the flatness of the surface of the resist 9 is transferred to the silicon oxide film, and the flattening of the insulator layer 6 is completed. In this case, in order to carry out the flattening process from the mechanism described above,
It is necessary that there is a condition that the resist 9 and the insulator layer 6 are etched at a constant rate. From FIG. 3, there is a silicon oxide film as an optimum insulator layer that satisfies this condition, and for this reason, a silicon oxide film is used as an insulator layer.

Thus, in the thin film magnetic head, the magnetic layers 3 and 7 are formed on the silicon oxide films forming the insulating layers 2, 4 and 6, and the magnetic layers are patterned into a core shape. It At this time, since it is necessary to pattern the cross-sectional shape of the core into a rectangular shape, it is necessary to overetch the magnetic layer. Then, in the over-etching of the magnetic layer, the silicon oxide film below the magnetic layer is also etched, and a step having a thickness greater than the film thickness of the magnetic layer is formed.

In FIG. 5A, a lower magnetic layer 3 having a thickness of 3 μm is formed on a first insulating layer 2 made of a silicon oxide film,
A state in which a resist pattern 10 having a core shape is formed by photolithography in order to pattern the lower magnetic layer 3 into a core shape is shown.

Next, as shown in FIG. 5B, for example,
Etching is performed for 45 minutes with a beam incident angle of 45 ° and an etching rate α of the magnetic layer of 660 Å / min. As a result, the portion of the magnetic layer 3 not covered with the resist pattern 10 disappears, and the first insulating layer 2 made of silicon oxide is exposed.

However, in order to obtain a core having a rectangular cross section, it is necessary to continue overetching for 40 minutes, and then, as shown in FIG.
As shown in (c), the already exposed silicon oxide film is etched to form a step 11 in the insulator layer 2. Normally, this step reaches about 3 μm.

[0016]

As described above, in the thin film magnetic head using the conventional silicon oxide film as the insulating layer, an unnecessarily large step 11 is formed when the core pattern of the magnetic layer is formed by etching. There is a problem that it is formed. The step is preferably as small as possible. If the step is large, the coil (conductor layer 5) formed on the magnetic layer 3 via the insulating layer will be broken.

The present invention has been made in view of the above problems, and suppresses the step of the insulating layer that occurs during patterning of the magnetic layer formed on the insulating layer as much as possible.
An object of the present invention is to provide a thin film magnetic head capable of avoiding the occurrence of disconnection of a coil formed on this.

[0018]

A thin film magnetic head according to the present invention includes a substrate, a first insulator layer, a first magnetic layer, a second insulator layer, a conductor layer, which are sequentially formed on the substrate. In a thin film magnetic head having a third insulating layer and a second magnetic layer, each of the first insulating layer and the third insulating layer has a two-layer structure of an upper layer and a lower layer. The upper layer can be formed of, for example, a tantalum pentoxide film, and the lower layer can be formed of, for example, a silicon oxide film. However, the constituent material of the upper layer and the lower layer is not limited to this, and the upper layer may have a slow etching rate, and the lower layer may have a material capable of matching the etching rate with the resist.

[0019]

In the present invention, the first and third insulator layers have a two-layer structure of an upper layer and a lower layer. Therefore, materials having different etching rates can be used for the upper and lower insulating layers. Therefore, as the upper insulator layer, a tantalum pentoxide film having a small etching rate is used. As the lower insulating layer, there is a silicon oxide film having the same etching rate as that of the resist.
As a result, when the magnetic layer is etched, the upper layer of the insulating layer having a slow etching rate is exposed, so that the excessive etching amount can be reduced and the step can be reduced. When the second magnetic layer is formed, the surface of the lower layer of the insulating layer is not flat. Therefore, the upper layer of the insulating layer is formed after the lower layer is flattened by a known method to flatten the upper layer surface. can do.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1A to 1C are sectional views showing a method of manufacturing a thin film magnetic head according to an embodiment of the present invention in the order of steps. As shown in FIG. 1A, an insulator layer lower layer 12 made of, for example, a silicon oxide film having a film thickness of 18 μm is formed on a non-magnetic substrate 1, and a film having a film thickness of, for example, 18 is formed on the lower layer 12. Upper layer 1 of insulator layer consisting of 2 μm tantalum pentoxide film
3 is sequentially formed by sputtering. After that, the first magnetic layer 3 made of permalloy and having a thickness of 3 μm, for example, is formed on the upper layer 13 by sputtering. Next, a resist pattern 10 corresponding to the shape of the lower core is formed on the first magnetic layer 3 by photolithography.

Next, as shown in FIG. 1B, the beam incident angle θ is set to 45 °, and the first magnetic layer 3 is etched by ion etching for 85 minutes, for example. In this case, the etching rates of the permalloy film and the tantalum pentoxide film are 660 Å / min and 400 Å / min, respectively.

As a result, as shown in FIG. 1 (c), the first
The magnetic layer 3 is etched into a rectangular cross section, and the upper layer 13 of the insulating layer is slightly overetched, resulting in a step 1
4 is formed. However, since the upper layer 13 is formed of a tantalum pentoxide film having an etching rate slower than that of the resist 10, the etching amount of the upper layer 13 is small, and therefore the step 14 of the upper layer 13 is small.

In practice, as a result of etching the first magnetic layer 3 into a rectangular cross section under the above-mentioned conditions, the resulting step difference is 1.6 μm.
Met. This was about half that in the case where a conventional single layer of silicon oxide film was used as an insulator layer.

Further, in the case of patterning the second magnetic layer 7 (see FIG. 2), as the third insulating film, instead of the conventional insulating layer 6, first, the insulating layer lower layer is oxidized, for example. It is formed of a silicon film, and its surface is flattened in the step shown in FIG. An upper layer made of a tantalum pentoxide film is formed with a film thickness of 2 μm, for example, on the lower layer made of the silicon oxide film after the planarization process.

Then, similarly to the embodiment shown in FIG.
After forming the second magnetic layer (magnetic layer 7), this is patterned by etching. Then, when the second magnetic layer is over-etched until the cross-sectional shape becomes rectangular, the upper layer made of the tantalum pentoxide film is slightly etched to cause a step, which is the same as in the embodiment shown in FIG. It was 0.6 μm, which was remarkably reduced as compared with the conventional one.

[0027]

As described above, according to the present invention,
Since the insulator layer has a two-layer structure of an upper layer and a lower layer, the upper layer and the lower layer can be formed of materials having mutually different etching rates, and the step difference of the insulator layer generated when patterning the magnetic layer is higher than in the conventional case. It can be reduced. Therefore, inconvenience such as disconnection of the coil formed on it can be suppressed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a process of manufacturing a thin film magnetic head according to an embodiment of the invention.

FIG. 2 is a cross-sectional view showing a schematic structure of a thin film magnetic head.

FIG. 3 is a graph diagram comparing etching rates of various materials.

FIG. 4 is a cross-sectional view showing a step of flattening an insulating layer.

FIG. 5 is a cross-sectional view showing a patterning step of a magnetic layer.

[Explanation of symbols]

 1: substrate 2, 4, 6, 8; insulator layer 3, 7; magnetic layer 5; conductor layer (coil) 12: lower layer 13: upper layer 10: resist 11, 14: step

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masato Otsu Inventor Masato Otsu 1-5-5 Takatsukadai, Nishi-ku, Kobe-shi, Hyogo Inside Kobe Research Institute, Kobe Steel, Ltd. (72) Takayuki Hirano Takatsuka, Nishi-ku, Kobe-shi, Hyogo 1-5-5 stand, Kobe Steel, Ltd. Kobe Research Institute

Claims (3)

[Claims] 1. A substrate and a first insulator layer, a first magnetic layer, a second insulator layer, a conductor layer, a third insulator layer and a second magnetic layer which are sequentially formed on the substrate. A thin-film magnetic head having the above-mentioned first insulating layer and third insulating layer each having a two-layer structure of an upper layer and a lower layer. 2. The thin film magnetic head according to claim 1, wherein the upper layer is a tantalum pentoxide film. 3. The thin film magnetic head according to claim 1, wherein the lower layer is a silicon oxide film.