JPH07211573A - Manufacture of soft magnetic thin film - Google Patents

Abstract

PURPOSE:To stably obtain a good soft magnetic characteristic by a method wherein, when a soft magnetic thin film is formed on a substrate by sputtering a target in a gas atmosphere, an inert gas and an unsaturated hydrocarbon-based gas are used as gases. CONSTITUTION:An Fe-C thin film is manufactured under a gas atmosphere by argon gas and ethylene gas by using a DC magnetron sputtering apparatus. As an inert gas to be used, helium or neon is enumerated in addition to argon. In addition, as an unsaturated hydrocarbon-based gas, acethylene, allene, isobuthylene, 1,3 butadiene, 1 butene, propylene, methyl acethylene or the like is enumerated in addition to ethylene. Thereby, it is possible to stably obtain a thin film whose soft magnetic characteristic is good.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a soft magnetic thin film.

[0002]

2. Description of the Related Art Permalloy and amorphous alloys have been known as soft magnetic thin film materials mainly for magnetic heads. As the thin film material, of course, the same composition as that of the bulk material is used, but various compositions containing various gas elements, which are difficult to produce with the bulk material, have been extensively studied. Nitrogen, oxygen, carbon, etc. are known as gas elements, but especially in the case of a thin film containing carbon in Fe, it is possible to amorphize relatively easily and obtain good soft magnetic characteristics. be able to.

As a method of manufacturing the above-mentioned carbon-containing thin film, for example, Journal Applied Physics 61
(12), 5480 to 5483 (1987), a method of performing sputtering by disposing a carbon tip on a Fe target to form a composite target is shown. However, this method has a problem that the carbon concentration in the thin film must be adjusted by the number of carbon chips, and the film characteristics vary depending on the arrangement state of the carbon chips. Further, according to the description of JP-A-4-139805, using a target containing no carbon, a reactive sputtering method is shown in which sputtering is performed in a gas atmosphere in which methane gas is mixed in an inert gas, and in particular, According to this method, it is easy to control the carbon concentration in the film, and there is an advantage that a thin film having a desired carbon concentration can be obtained.

[0004]

However, in order to obtain excellent soft magnetic characteristics in the above method, a large amount of methane gas must be introduced. When such a large amount of methane gas is introduced, the target surface Therefore, it was difficult to stably obtain good soft magnetic characteristics because the contamination of (1) progresses rapidly. In other words, in the production method in which carbon is contained in the thin film, the soft magnetic properties are not sufficient in the conventionally used saturated hydrocarbon gas, and it is difficult to stably produce the thin film. Met. It is an object of the present invention to provide a method for manufacturing a soft magnetic thin film that can stably obtain good soft magnetic characteristics.

[0005]

Means for Solving the Problems As a result of intensive studies to solve such problems, the present inventors have found that film formation is carried out in a gas atmosphere of an inert gas and an unsaturated hydrocarbon-based gas. The inventors have found the fact that good soft magnetic characteristics can be stably obtained, and arrived at the present invention. That is, the present invention is characterized in that when forming a soft magnetic thin film on a substrate by sputtering a target in a gas atmosphere, an inert gas and an unsaturated hydrocarbon-based gas are used as gases. The manufacturing method is as a gist.

The present invention will be described in detail below. As the inert gas used in the present invention, argon, helium,
Neon is given. Further, as the unsaturated hydrocarbon-based gas, a gas which is usually commercially available may be used. Specific examples thereof include acetylene, allene, isobutylene, ethylene, 1.3 butadiene, 1-butene, propylene and methylacetylene. Furthermore, in the above unsaturated hydrocarbon-based gas used in the present invention,
It may be one in which hydrogen is replaced by a halogen element such as chlorine, fluorine or bromine. Examples of the target used in the present invention include pure Fe or Fe-X (X = Si, B, P).
10 to 30 atomic% of at least one element),
Fe-Y (Y = Zr, Hf, V, Nb, Ta consisting of at least one element of 5 to 30 atom%), Co-Fe-X (X = Si, at least one element of B, P) Of 10 to 30 atomic%). Further, the substrate used in the present invention includes, for example, glass, organic polymer film, and the like, and particularly, as the organic polymer,
Examples thereof include polyethylene terephthalate, polyamide, polyimide, polyphenylene sulfide, polysulfone, polyarylate, polyether sulfone, polypropylene and liquid crystal polymer.

As the sputtering apparatus used in the present invention, it is possible to use an existing one such as RF bipolar sputtering, DC sputtering, magnetron sputtering, tripolar sputtering, ion beam sputtering, and facing target type sputtering. Among these, the magnetron sputtering apparatus is advantageous when using an organic polymer film or the like having a relatively low heat resistance, because the deposition rate of the thin film is improved and the temperature rise of the substrate can be suppressed to a relatively low level. In the magnetron sputtering method, a magnetic field is applied in the direction perpendicular to the electric field applied to the target to improve the sputtering efficiency by moving the charged particles in the plasma by cyclotron motion and depositing the sputtered particles on the substrate installed in advance. Is the way to do it.

As the magnetic field for the cyclotron motion of the charged particles, a wetting magnetic field of a permanent magnet or an electromagnet arranged directly under the target is used, or a yoke is used from these permanent magnets or magnetic poles of the electromagnet. Further, there is a method of directly inducing a magnetic flux to increase the wetting magnetic field. Further, when an organic polymer material is used as a substrate for continuously producing a thin film, a roll-to-roll method is used in which an organic polymer film wound on a feed roll is deposited at a can portion. Can be used.

The production conditions for producing the soft magnetic thin film in the gas atmosphere of the above-mentioned inert gas and unsaturated hydrocarbon-based gas vary depending on the size of the chamber and the exhaust capacity of the vacuum pump. The ultimate pressure in the chamber during production is, for example, preferably 5 × 10 ⁻⁶ Torr or less, and more preferably 1 × 10 ⁻⁶ Torr or less. In addition, the flow rate of the inert gas is 20 to 20
0 CCM is suitable, 40-170 CCM is preferred, especially 60-15
0 CCM is more preferred. Further, the flow rate of the unsaturated hydrocarbon gas is preferably 0.5 to 30 CCM, and 2 to 25 CCCM.
M is preferable, and 5 to 20 CCM is particularly preferable.

[0010]

EXAMPLES Next, the present invention will be specifically described with reference to Examples and Comparative Examples. Example 1 and Comparative Example 1 A Fe-C thin film was prepared using a DC magnetron sputtering device (manufactured by Nichiden Anelva Co., Ltd.) under a gas atmosphere of argon gas and ethylene gas (manufactured by Steel Chemical Co., Ltd.). The manufacturing conditions at that time are shown below. Target: Pure Fe Substrate: Borosilicate glass (Substrate is water cooled) Ultimate pressure: 8 × 10 ^-7 Torr Argon gas flow rate: 100 CCM Ethylene gas flow rate: 0 to 20 CCM Film thickness: 5000 angstrom A thin film was prepared under the above manufacturing conditions The relationship between the flow rate of introduced ethylene gas and the coercive force at this time is shown in FIG. For comparison,
Fe-C thin films were similarly prepared using methane gas and ethane gas, which are saturated hydrocarbon gases. The manufacturing conditions are
The same conditions as above were used except that methane gas and ethane gas were used instead of ethylene gas. FIG. 1 shows the relationship between the coercive force and the flow rate of the introduced gas at that time.

FIG. 1 shows the coercive force (Oe) on the vertical axis and the introduced gas flow rate (CCM) on the horizontal axis. As is clear from this figure, when ethylene gas in the present invention is used, In addition, a remarkable effect appears in improving the soft magnetic characteristics, and further, the soft magnetic characteristics are excellent over a wide range of ethylene gas flow rates. On the other hand, when methane gas and ethane gas, which are saturated hydrocarbon gases, are used, the coercive force is reduced and the soft magnetic properties are improved. The magnetic properties did not improve.

Example 2 An Fe-C thin film was prepared in a gas atmosphere of helium gas and methylacetylene gas (manufactured by Iron Manufacturing Chemical Co., Ltd.) using a DC magnetron sputtering device (manufactured by Nichiden Anelva Co.). The manufacturing conditions at that time are shown below. Target: Pure Fe Substrate: Borosilicate glass (Substrate is water cooled) Ultimate pressure: 9 × 10 ^-7 Torr Helium gas flow rate: 80CCM Methylacetylene gas flow rate: 10CCM Film thickness: 0.3 μm Thin film obtained under the above conditions The coercive force was 0.4 Oe, indicating good soft magnetic properties.

Example 3 Using a DC magnetron sputtering apparatus (manufactured by Nichiden Anelva Co.), a roll-to-roll method was applied on a polyester film substrate in a gas atmosphere of argon gas and ethylene gas (manufactured by Steel Chemical Co., Ltd.). Fe-S with a thickness of about 0.6 μm
An iBC thin film was prepared. The roll-to-roll method is a method in which an organic polymer material such as a plastic film wound on a feed roll is deposited on a can while it is wound on a take-up roll via a cylindrical can. In this case, the polyester film wound on the feed roll was continuously produced through a cylindrical can having a diameter of 40 cm and a width of 60 cm at a speed of 0.25 m / min while being wound on a take-up roll to continuously produce 10 m. The manufacturing conditions at that time are shown below. Target: Fe ₇₅ Si ₁₀ B ₁₅ (Numbers indicate atomic%) Substrate: 125 μm thick, 300 mm wide polyester film Ultimate pressure: 8 × 10 ^-7 Torr Argon gas flow rate: 100 CCM Ethylene gas flow rate: 15 CCM

When the structure of the thin film produced under the above conditions was examined by an X-ray diffractometer (manufactured by Rigaku Denki Co., Ltd.), it was an amorphous single phase and had a coercive force of 0.3 Oe and showed good soft magnetic characteristics. It was Furthermore, no great variation in coercive force was observed in the length direction and width direction of the film. Here, the length direction of the film means a direction in which the film substrate is fed out and wound up, and the width direction means a direction perpendicular to the length direction.

Example 4 Using a DC magnetron sputtering device (manufactured by Nichiden Anelva) in a gas atmosphere of argon gas and acetylene gas (manufactured by Iron and Steel Chemical Co., Ltd.), the same rolls as in Example 3 were used.
By the tow roll method, while winding the polyester film substrate at a speed of 0.5 m / min, the thickness of about 0.3 μm
A Co-Fe-Si-BC thin film was continuously formed for 10 m. The manufacturing conditions at that time are shown below. Target: Co ₇₀ Fe ₅ Si ₁₀ B ₁₅ (Numbers indicate atomic%.) Substrate: Polyester film with thickness of 100 μm and width of 500 mm Ultimate pressure: 9 × 10 ^-7 Torr Argon gas flow rate: 100 CCM Ethylene gas flow rate: 15 CCM The coercive force of the thin film produced under the above conditions was 0.1 Oe, which was a very good soft magnetic property, and there was almost no variation in the coercive force in the length and width directions of the film.

Example 5 Using a DC magnetron sputtering device (manufactured by Nichiden Anelva Co.) in a gas atmosphere of argon gas and allene gas (manufactured by Steel Manufacturing Co., Ltd.), the same roll-to-roll method as in Example 3 was used. , While winding the polyester film substrate at a speed of 0.3 m / min, Co with a thickness of about 0.5 μm
-Fe-Si-BC thin film was continuously produced for 10 m. The manufacturing conditions at that time are shown below. Target: Co ₇₀ Fe ₅ Si ₁₀ B ₁₅ (Numbers indicate atomic%) Substrate: Polyester film with thickness of 75 μm and width of 300 mm Ultimate pressure: 8 × 10 ^-7 Torr Argon gas flow rate: 100 CCM Allen gas flow rate: 10 CCM The coercive force of the thin film produced under the above conditions showed a very good soft magnetic property at 0.2 Oe, and there was almost no variation in the coercive force in the length direction and the width direction of the film.

Example 6 A roll-to-roll method similar to that of Example 3 was performed in a gas atmosphere of argon gas and propylene gas (manufactured by Nippon Oxygen Co.) using a DC magnetron sputtering apparatus (manufactured by Nichiden Anelva Co.). The thickness is about 0.5 μm while winding the polyester film substrate at a speed of 0.4 m / min.
Fe-C thin film of 50 m was continuously produced. The manufacturing conditions at that time are shown below. Target: Pure Fe Substrate: Polyester film with a thickness of 75 μm and width of 300 mm Ultimate pressure: 7 × 10 ^-7 Torr Argon gas flow rate: 100 CCM Propylene gas flow rate: 10 CCM Coercive force of the thin film produced under the above conditions every 5 m When examined at 10 points, coercive force was 0.2 to 0 at all points.
It was within the range of 25 Oe, and it was confirmed that good soft magnetic characteristics were stably obtained.

Example 7 Using a DC magnetron sputtering apparatus (manufactured by Nichiden Anelva), in a gas atmosphere of argon gas and 1.3 butadiene gas (manufactured by Iron and Steel Chemical Co., Ltd.), the same roll-to-roll method as in Example 3 was used. According to the method, the thickness is about 0.4 while winding the polyester film substrate at a speed of 0.3 m / min.
A 50 μm Fe-Si-BC thin film was continuously formed. The manufacturing conditions at that time are shown below. Target: Fe ₇₅ Si ₁₀ B ₁₅ (Numbers indicate atomic%.) Substrate: Thickness 75 μm: Polyester film with width 300 mm Ultimate pressure: 8 × 10 ^-7 Torr Argon gas flow rate: 90 CCM 1.3 Butadiene gas: 7 CCM Above When the coercive force of the thin film prepared under the condition of was examined at 10 locations every 5 m, the coercive force was 0.3 to 0 at all points.
It was within the range of 4 Oe, and it was confirmed that good soft magnetic characteristics could be stably obtained.

[0019]

According to the present invention, a thin film having good soft magnetic characteristics can be stably obtained by performing sputtering using an inert gas and an unsaturated hydrocarbon gas. The soft magnetic thin film thus obtained is
It can be used for magnetic shields, anti-theft signs, magnetic sensors, rotation sensors, etc.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a flow rate of an introduced gas and a coercive force in Example 1 which is the present invention and Comparative Example 1 which is a conventional technique.

Claims (1)

[Claims] 1. When forming a soft magnetic thin film on a substrate by sputtering a target in a gas atmosphere, an inert gas and an unsaturated hydrocarbon-based gas are used as the gas. Production method.