JPH0536558A - Method for forming magnetic thin film - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a method for forming a magnetic thin film used for a magnetic pole or the like of a thin film magnetic head for a magnetic disk device, and has a smooth surface and a good magnetic permeability by a sputtering method under a high sputtering gas pressure. The purpose is to form a magnetic thin film having the same. [Structure] When a magnetic thin film containing iron as a main component is formed on a base material film 22 facing the Fe target 4 by a sputtering method, the sputtering gas pressure during the film formation is set to 5 mTorr or more, and the base material is formed. A bias voltage is applied to the substrate supporting electrode 6 on the film 22 side. Further, the inclination angle θ of the surface of the base material film 22 facing the Fe target 4 is set to 30 degrees or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a magnetic thin film used for a magnetic pole of a thin film magnetic head for a magnetic disk device.

When a thin film is formed by a sputtering method, a thin film having a smooth surface is formed by forming the thin film under the condition that the pressure of the sputtering gas is sufficiently low so that the surface of the formed thin film does not become uneven. It is generally done.

However, when a magnetic thin film or the like is formed by the same sputtering method, the magnetic properties of the magnetic thin film to be formed change depending on the pressure of the sputtering gas. Therefore, in order to improve the magnetic properties of the magnetic thin film. Requires that the pressure of the sputtering gas be increased. Therefore, there is a demand for a method of forming a magnetic thin film having a smooth surface and good magnetic characteristics.

[0004]

2. Description of the Related Art Conventionally, a magnetic thin film for forming a magnetic pole of a thin film magnetic head has a substrate arranged on a substrate supporting electrode facing a Fe target in a sputtering apparatus, and has a gas pressure of 12 mTorr.
In a sputtering gas prepared by adding N ₂ gas having a gas pressure of 0.4 mTorr in an Ar gas atmosphere, high-frequency sputtering power of 600 w is supplied between the two to obtain a predetermined film thickness by the sputtering method.
A magnetic thin film made of FeN is formed.

And, such FeN magnetic thin film is shown in FIG.
3A is a plan view of FIG. 3A and FIG.
In a thin film magnetic head as shown in the cross-sectional view of the main part of (b), the lower magnetic pole layer 12 disposed on the nonmagnetic substrate 11 made of, for example, ceramics, and the nonmagnetic substrate 11 including the lower magnetic pole layer 12. A spiral thin film coil 15 sandwiched by a gap layer 13 and an interlayer insulating layer 14 made of a thermosetting resin on the surface of the
And the upper magnetic pole layer 16 arranged so as to be directly connected to the lower magnetic pole layer 12 at the other end. It is used to form layers. A thick inorganic protective film 17 made of Al ₂ O ₃ covers these surfaces.

[0006]

By the way, when the FeN magnetic thin film forming the lower magnetic pole layer 12 and the upper magnetic pole layer 16 is formed by the sputtering method, the FeN formed is formed.
If the pressure of the sputter gas is increased to about 12 mTorr to reduce the compressive stress (strain in the compressive direction) generated in the magnetic thin film, the growth of crystal grains during film formation becomes remarkable and the surface of the FeN magnetic thin film becomes uneven. Therefore, the phenomenon that the magnetic permeability decreases due to this occurs. In particular, when the FeN magnetic thin film forming the upper magnetic pole layer 16 is formed, the growth of crystal grains in the step portion D becomes remarkable, and the magnetic permeability of the step portion D is significantly reduced as compared with the other portions. Bottom pole layer
There is a problem that the reproducing characteristics of the thin film magnetic head having the 12 and the top pole layer 16 are deteriorated.

In view of the above-mentioned conventional problems, it is an object of the present invention to provide a novel method for forming a magnetic thin film having a smooth surface and good magnetic characteristics by a sputtering method in which the pressure of a sputtering gas is increased. It is a thing.

[0008]

In order to achieve the above-mentioned object, the present invention provides a method of forming a magnetic thin film containing iron as a main component on a base material facing a target by a sputtering method. The sputtering gas pressure is set to 5 mTorr or more, and a bias voltage is applied to the supporting electrode on the base material side to form a film.

Further, the inclination angle of the surface of the base material facing the target is set to 30 degrees or less.

[0010]

[Function] When a FeN magnetic thin film containing iron as a main component is formed on a substrate by a sputtering method in which a trace amount of N ₂ gas is added to Ar gas and the sputtering gas pressure is 5 mTorr or more, the substrate side is supported. By applying a negative bias voltage to the electrode, Ar gas ionized Ar ions are attracted to and impact the area of the film surface where the sputtered material is deposited and the crystal grains grow significantly. The film formation is performed while suppressing the rapid growth of the crystal grains. As a result, it is possible to obtain a FeN magnetic thin film having a smooth film surface and good magnetic characteristics (permeability and the like).

Further, by the action of the above-mentioned sputtering conditions and the inclination angle of the substrate surface with respect to the target being 30 degrees or less, the film surface is smooth even on the substrate surface inclined to the 30 degrees or less, In addition, it is possible to obtain a FeN magnetic thin film having excellent magnetic properties (permeability, etc.).

[0012]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of a sputtering apparatus used in the method for forming a magnetic thin film according to the present invention.

As shown in the drawing, a vacuum exhaust system 2 and a sputtering gas introducing pipe 3 in a parallel plate bipolar high frequency sputtering apparatus.
The target electrode 5 supporting the Fe target 4 and the cured resin film used for covering and insulating the coil of the thin film magnetic head are applied in advance in the sputtering chamber 1 provided with
A water-cooled substrate supporting electrode 6 supporting a glass substrate 21 on which a base film 22 having a stepped portion 22a having an inclined surface of 30 ° is disposed is arranged to face.

Next, the inside of the sputtering chamber 1 is evacuated to a vacuum exhaust system 2.
After evacuating to a high vacuum of at least 10 ^-6 Torr by
Nitrogen (N ₂ ) gas was supplied at 3 atm% from the sputter gas inlet pipe 3.
The added argon (Ar) gas was introduced so that the gas pressure of the argon (Ar) gas was 12 mTorr and the gas pressure of the nitrogen (N ₂ ) gas was 0.4 mTorr, and the bias DC was applied to the substrate supporting electrode 6. With a bias voltage of −50 V applied from the power supply 7, a high frequency power supply 8 is applied between the substrate supporting electrode 6 and the target electrode 5.
Sputtering is performed by supplying high-frequency power of 600 W to generate plasma discharge.

As shown in the cross-sectional view of the main part of FIG. 2, a cured resin film used for coating and insulating the coil of the thin film magnetic head is previously applied by such sputtering, and has an inclined surface of θ = 30 °. The FeN sputtered material is deposited on the entire surface of the glass substrate 21 including the base material film 22 in which the step portion 22a is partially formed, and at the same time, a portion where the FeN sputtered substance is projected to the film surface due to the remarkable growth of crystal grains The Ar gas is attracted and bombarded by the negative bias voltage to which the ionized Ar ions are applied, so that the rapid crystal growth of the protruding crystal grains is suppressed and the film formation is performed.

Therefore, it becomes possible to easily form the FeN magnetic thin film 23 having a predetermined film thickness, in which the entire film surface including the film surface on the step portion is smooth and has uniform magnetic characteristics (permeability and the like). .

Incidentally, it is formed by the method of this embodiment.
Table 1 shows the results of measuring various characteristics of the FeN magnetic thin film and the FeN magnetic thin film formed by the conventional method.

[0018]

[Table 1]

As is clear from Table 1, the surface roughness and magnetic permeability of the FeN magnetic thin film formed by the method of this embodiment are almost the same even when the film forming surface inclinations θ = 0 ° and θ = 30. It was found that it did not change, and the results were superior to the surface roughness and magnetic permeability of the FeN magnetic thin film formed by the conventional method.

In the above embodiments, the magnetic thin film containing iron as the main component for forming the lower magnetic pole layer and the upper magnetic pole layer was used as F
Although the example using the eN magnetic thin film has been described, the present invention is not limited to this example.
The same effect can be obtained when a magnetic thin film containing Ta or the like is applied.

[0021]

As is apparent from the above description, according to the method of forming a magnetic thin film of the present invention, when the magnetic thin film containing iron as a main component is formed by the sputtering method, the bias electrode is formed on the substrate supporting electrode. By applying the magnetic field, even if the film-forming surface is partially inclined from the target surface by 0 ° to 30 °, the entire surface of the magnetic thin film formed is smooth and the magnetic characteristics (permeability Etc.) has the excellent advantage of being able to easily obtain a magnetic thin film.

Therefore, when applied to the formation of a magnetic pole having a step portion in the manufacturing process of various thin film magnetic heads, a remarkable effect is exerted, and it greatly contributes to the performance improvement of various thin film magnetic heads.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a sputtering apparatus used in a method for forming a magnetic thin film according to the present invention.

FIG. 2 is a cross-sectional view of an essential part for explaining an embodiment of a method for forming a magnetic thin film according to the present invention.

FIG. 3 is a diagram showing a thin film magnetic head for explaining a conventional method of forming a magnetic thin film.

[Explanation of symbols]

1 Sputtering room 2 vacuum exhaust system 3 Sputter gas introduction tube 4 Fe target 5 Target electrode 6 Substrate support electrode 7 DC power supply for bias 8 high frequency power supply 21 glass substrate 22 Base film 22a Step portion 23 FeN magnetic thin film

Claims (2)

[Claims] 1. A target (4) prepared by a sputtering method.
When a magnetic thin film containing iron as a main component is formed on the base material (22) facing the base material (22), the sputtering gas pressure during the film formation is set to 5 mTorr or more, and the support electrode (on the base material (22) side ( A method for forming a magnetic thin film, which comprises applying a bias voltage to 6). 2. A substrate (22) facing the target (4)
The method for forming a magnetic thin film according to claim 1, wherein the inclination angle of the surface is 30 degrees or less.