JP2751696B2 - Method for manufacturing thin-film magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the manufacture of an inductive thin-film magnetic head used for a magnetic disk drive, a magnetic tape drive and the like.
The present invention relates to a method , and particularly to a material forming a magnetic gap usually called a magnetic gap.

[0002]

2. Description of the Related Art In the field of magnetic recording in recent years, as the recording density has increased and the magnetic head supporting the magnetic recording technology together with the recording medium has been increased, a thin film magnetic head using an integrated thin film technology has replaced the conventional ferrite head. Has been put to practical use. This thin-film magnetic head has excellent frequency characteristics, and a manufacturing process based on semiconductor technology is applied, making it possible to manufacture a high-precision magnetic head for high recording density at a low price. It is becoming.

FIG. 3 is a schematic sectional view showing the structure of the above-mentioned thin film magnetic head. In FIG. 3, an insulating layer 12 is formed on a substrate 10 made of alumina-titanium carbide or the like by using a known thin film forming method (for example, a sputtering method). Next, the lower magnetic layer 13 made of a soft magnetic material is used.
Are formed using integrated thin film technology. Thereafter, a magnetic gap layer 14 having a thickness equal to a predetermined gap length is formed. Then, the step eliminating layer 15 of the lower magnetic layer 13 is formed.
Is formed, and the coil 16 made of a conductive material is formed. After that, the step eliminating layer 17 of the coil 16 is formed. Next, the upper magnetic layer 18 is formed in the same manner as the lower magnetic layer 13, and a protective layer (not shown) is formed to complete the transducer of the thin-film magnetic head.

By the way, as a method of processing the upper and lower magnetic layers 18 and 13 respectively, and in particular, a method of processing the upper and lower magnetic layers 18 and 13 using an iron-based high saturation magnetization material, the 14th Japan Society of Applied Magnetic Science. Summary of Academic Lectures 165
A page (hereinafter referred to as Reference 1) discloses a reactive ion etching method using a chlorine-based gas. This method uses an inert gas (for example, A) which has been generally used as a method of processing the upper magnetic layer 18 or the lower magnetic layer 13.
This is a processing method capable of realizing a rectangular cross-section pattern at a higher etching rate than the ion milling method using r gas). In the future, an iron-based high saturation magnetization material will be used as a material for forming the upper or lower magnetic layers 18 and 13. It is expected that it will be adopted as a new processing method for the upper or lower magnetic layer as it is used.

[0005]

However, the above-described reactive ion etching method using a chlorine-based gas is employed in the pole machining step of the thin-film magnetic head, and the lower magnetic layer 13 and the upper magnetic layer 18 are collectively formed. In the case where a thin film magnetic head having a predetermined track width is manufactured by processing, there are problems as described below.

That is, a magnetic gap layer 14 serving as a magnetic gap is inserted between the lower magnetic layer 13 and the upper magnetic layer 18. Usually, the material of the magnetic gap layer 14 is
Although an alumina film having a thickness of about 0.2 to 0.3 μm is used, the magnetic gap layer is processed continuously with the magnetic layer using the magnetic layer processing method disclosed in Reference 1. In this case, there is a problem that the etching rate of the alumina film forming the magnetic gap layer 14 is extremely slow, the magnetic pole processing time is abnormally long, and the throughput in manufacturing the head is poor. For example, when the material forming the magnetic layer is an FeSiAl alloy, as already described in Reference 1,
The selectivity of the alumina film to the film is as large as about 20. Therefore, when the thickness of the magnetic gap layer 14 is 0.3 μm, the time required to process the alumina film of only 0.3 μm is approximately equal to the sum of the thicknesses of the upper and lower magnetic layers 13 and 18. It can be estimated to be equivalent to the time required to process a 6 μm FeSiAl film, and the calculation is such that half of the magnetic pole processing time of the thin-film magnetic head is spent processing the magnetic gap layer 14.

An object of the present invention is to provide a novel thin-film magnetic head manufacturing method which solves the above-mentioned problems in the magnetic pole machining step of the thin-film magnetic head .

[0008]

According to the present invention, there is provided a magnetic circuit comprising a magnetic layer, a magnetic gap layer (magnetic gap) comprising a nonmagnetic material formed in the magnetic circuit, and the magnetic circuit. production side of the inductive thin-film magnetic head having a coil made of a conductor film formed to Mata交in
In the method, processing of the magnetic layer is performed in a chlorine-based gas.
The magnetic gap layer mainly contains oxygen
Using reactive ion etching in gas
Process. In particular, when the magnetic gap layer is a carbon film,
Is valid.

[0009]

[0010]

As has been pointed out in Reference 1, alumina, which is generally used as a magnetic gap material, is extremely stable even with a very active substance such as a chlorine-based gas, and is etched very little. Although various studies were conducted, it was extremely difficult to process alumina at high speed within the range studied by the present inventors, and it was judged that further improvement in throughput could not be expected as long as the material forming the magnetic gap was alumina. Was. Therefore, the inventor once again examined the material of the magnetic gap layer capable of high-speed processing and the processing method. As a result, the material forming the magnetic gap layer is made of a carbon film, and the processing of this carbon film is performed using a reactive ion etching method in a gas containing oxygen gas as a main component. And a method for manufacturing a thin-film magnetic head with good throughput can be realized. Hereinafter, the processing speed of the carbon film when etched by several processing methods will be described.

For the study of the processing method, the following three methods were examined using a commercially available parallel plate type ion etching apparatus. Method 1: Reactive ion etching in a chlorine-based gas disclosed in Document 1.

Gas type: carbon tetrachloride, gas pressure: 3.5P
a, input power: 150 W Method 2: Ion etching method in Ar gas.

Gas type: Ar, gas pressure: 3.5 Pa, input power: 150 W Method 3: Reactive ion etching in oxygen gas.

Gas type: oxygen, gas pressure: 3.5 Pa, input power: 150 W The processing speed was measured by measuring the time required to remove a 1 μm-thick carbon film by etching, and the film thickness was measured by this etching. The processing speed per unit time was determined by dividing by time.

The processing speed of the carbon film obtained by the above three methods is 15 nm / min in method 1 and 14 nm in method 2
nm / min, and 150 nm / min in Method 3. Therefore, when the thickness of the magnetic gap layer is, for example, 0.3 μm,
The time required to process the magnetic gap layer is about 20 minutes in the methods 1 and 2, while the method 3 allows
It became clear that the magnetic gap layer could be processed in only 2 minutes. Therefore, by using the magnetic gap layer as a carbon film and using method 3 as a processing method thereof, the throughput of the magnetic pole processing step can be much improved as compared with the case where conventional alumina is used as the magnetic gap layer.

[0016]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view of a thin-film magnetic head used in the present invention. In FIG. 1, an insulating layer 12 made of alumina or the like is formed on a substrate 10 of Al ₂ O ₃ —TiC or the like. Next, the lower magnetic layer 13 was formed by using a known integrated thin film technique. The material of the lower magnetic layer 13 is FeSiA
1 (Si: 9.6 wt%, Al: 5.4 wt%), and the film thickness is 3 μm. The lower magnetic layer 13 was formed such that its track width was larger than a predetermined track width by about 5 μm on each side.

Next, a carbon film 19 (thickness: 0.3 μm) to be a magnetic gap (magnetic gap layer) was formed by sputtering. The film forming conditions are as follows: Ar gas pressure: 5 mTorr, input power: 400 W. Thereafter, the step eliminating layers 15 and 17 and the coil 16 were formed. A copper plating film was used for the coil as a conductor thin film, and the plating thickness was 3 μm. In addition, a silicon oxide film was used for the step eliminating layers 15 and 17. The coil 16 was completely embedded and flattened by using a bias sputtering method for film formation. After forming the step difference eliminating layers 15 and 17, each was chemically etched in a solution containing hydrofluoric acid so that the front gap portion and the rear gap portion were tapered as indicated by arrows in FIG.

Then, similarly to the lower magnetic layer 13,
An FeSiAl film to be the upper magnetic layer 18 was formed. Thereafter, a magnetic pole processing step was performed to obtain a predetermined track width W. This step will be described with reference to FIG. FIG.
Corresponds to the AA cross section in FIG.

As shown in FIG. 2A, the upper magnetic layer 1
8, a mask pattern having a width substantially equal to the predetermined track width W was formed. The material of the mask pattern was silicon oxide, and the film thickness was 1.5 μm.

Then, as shown in FIG. 2B, the upper magnetic layer 18 is formed by a reactive ion etching method in a chlorine-based gas.
Was patterned. The etching conditions are as follows: gas type: carbon tetrachloride, gas pressure: 3.5 Pa, and input power: 150 W.

Subsequently, as shown in FIG. 2C, the gas type was changed to oxygen, and the carbon film 19 was etched. The etching conditions were as follows: gas pressure: 3.5 Pa, input power: 150 W
It is.

Thereafter, as shown in FIG. 2D, the etching gas was changed again to carbon tetrachloride, and the lower magnetic layer 15 was processed in exactly the same manner as the processing of the upper magnetic layer 18. Next, the mask pattern was removed (not shown) to complete a thin-film magnetic head having a predetermined track width W.

In the above-described thin-film magnetic head, it takes only two minutes to process the carbon film serving as a magnetic gap in the magnetic pole processing step, which is about a minute compared to a conventional thin-film magnetic head using an alumina film. The processing time was 1/10.

In the above embodiment, only the case where pure oxygen gas is used is shown. However, the present invention is intended to be applied to other gases as long as the processing speed of the carbon film is not significantly reduced. Of course, it is not damaged.

[0026]

As described above, in the method of manufacturing a thin-film magnetic head according to the present invention, the carbon film is used as the material of the magnetic gap layer, and the carbon film is processed in a gas containing oxygen as a main component. By performing the ion etching method, the throughput in the magnetic pole processing step can be drastically increased, and it can be said that it has great industrial significance.
Further, the carbon film has a lubricating effect, has an advantage that it contributes to the reliability between head media from the viewpoint of tribology, and has an effect that the reliability of the head can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a thin-film magnetic head used in the present invention.

FIG. 2 is a diagram illustrating a method of manufacturing a thin-film magnetic head according to the present invention.

FIG. 3 is a view for explaining a conventional thin-film magnetic head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Substrate 12 Insulating layer 13 Lower magnetic layer 14 Magnetic gap layer 15, 17 Step cancellation layer 16 Coil 18 Upper magnetic layer 19 Carbon film (magnetic gap layer)

Claims (2)

(57) [Claims] In a method of manufacturing a thin film magnetic head, a magnetic pole processing step includes a step of processing a magnetic layer using a reactive ion etching method in a chlorine-based gas, and a step of processing a magnetic layer in a gas containing oxygen as a main component. Processing the magnetic gap layer by the reactive ion etching method of (1). 2. The method according to claim 1, wherein said magnetic gap layer comprises a carbon film.