JP3783750B2 - Method for producing sputtered film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a sputtered film at a high film formation rate.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, various metals and metal compounds have been widely produced by sputtering, and various sputtering methods and sputtering apparatuses have been proposed.
[0003]
For example, Japanese Patent Publication No. 62-56575, Japanese Patent Publication No. 63-20304, and Japanese Patent Publication No. 3-1810 propose a facing target type sputtering method, which produces a perpendicular magnetic film with good crystallinity. It is disclosed.
[0004]
However, the conventional facing target sputtering method has a problem that the film forming speed is low, and a solution to this problem has been desired.
[0005]
Means for Solving the Problem and Embodiment of the Invention
As a result of diligent investigations in order to meet the above demand, the present inventor has arranged a substrate on the side of the sputtering space between the targets facing each other and formed a sputtered film on the substrate by sputtering using a counter target sputtering method. It has been found that when a film is produced, a film can be formed at a high speed by applying an alternating voltage 180 degrees out of phase to both the targets.
[0006]
That is, in the facing target type sputtering method, there are two cathodes (targets) facing each other. In the conventional method, a direct current or an alternating voltage is applied to these cathodes in the same phase. The film speed is slow. In particular, when reactive gas is introduced and reactive sputtering is performed, the deposition rate is extremely reduced in terms of reaction with the reactive gas. However, in the facing target sputtering method, by applying an alternating voltage 180 degrees out of phase to two targets facing each other, particularly in the case of the reactive sputtering method, a metal compound having excellent crystallinity can be formed at high speed. For example, when titanium metal is used as a target and a titanium oxide thin film is produced by introducing an inert gas and a gas having oxygen molecules into the sputtering space, anatase-type crystal rich having high photocatalytic activity at high speed. It has been found that a thin film can be formed.
[0007]
In this case, an AC sputtering method in which the phase is shifted by 180 degrees is proposed in Japanese Patent Laid-Open Nos. H5-222531 and H6-212421. However, this type of conventional AC sputtering method is a method in which two targets are arranged in parallel without facing each other, and a substrate on which a sputtered film is to be formed is disposed facing these targets and sputtering is performed. In this method, the substrate is exposed to plasma discharge, and particularly when a titanium oxide photocatalyst film is formed, the resulting film has an amorphous structure, so that there is almost no catalytic activity. By applying an alternating voltage shifted by 180 degrees, a photocatalytic film having an anatase structure can be obtained at high speed.
[0008]
In addition, when applying AC voltages that are 180 degrees out of phase with each other, the apparatus used in this conventional AC sputtering method generates an AC signal having a frequency that is 180 degrees out of phase based on the signal output from the signal generator. Although a high voltage and a high current are obtained by amplification, a complicated circuit is required to create a signal, and the apparatus is expensive, and thus the production cost of the sputtered film is also expensive. However, by using the single-phase compound winding step-up transformer, the commercial 50 Hz or 60 Hz single-phase alternating current can be used as they are, and alternating current signals that are 180 degrees out of phase with each other can be provided. The present inventors have found that a sputtered film can be produced at a low cost and have made the present invention.
[0009]
Therefore, the present invention
Claim 1:
When a sputtered film is formed by the facing target sputtering method in which a substrate is placed beside the sputtering space between the titanium targets facing each other and a sputtered film is formed on the substrate, a single-phase alternating current is boosted to a single-phase alternating current. While boosting with a transformer, AC signals that are 180 degrees out of phase with each other are formed, AC voltages that are 180 degrees out of phase with each other are applied to the two titanium targets, and inert gas and oxygen molecules are introduced into the sputtering space. There is provided a method for producing a sputtered film, which comprises introducing a gas having an anatase-structured titanium oxide photocatalytic film on a substrate.
[0010]
Hereinafter, the present invention will be described in more detail. The method for producing a sputtered film of the present invention is to form a film using an opposed target type sputtering apparatus. In this case, two targets arranged opposite to each other are used. Sputtering is performed by applying an AC voltage that is 180 degrees out of phase.
[0011]
Here, as this counter target type sputtering apparatus, it can be set as a well-known apparatus aspect except a power supply, for example, the apparatus shown in FIG. 1 can be used. That is, in FIG. 1, reference numeral 1 denotes an apparatus main body capable of degassing the inside, and a pair of metal targets 2 and 2 are disposed in the apparatus main body 1 so as to face each other with a predetermined distance therebetween. These targets 2 and 2 are held by holds 3 and 3 having support portions 3a and 3a, respectively, and are connected to a sputtering power source (AC power source) 4 through these holds 3 and 3, and the targets 2 and 2 are also connected. Are arranged so that different magnetic poles face each other, and a magnetic field perpendicular to the targets 2 and 2 is generated in the sputtering space 6 between the targets 2 and 2. . A substrate 7 on which a sputtered film is to be formed is disposed on the side of the sputter space 6. Reference numeral 8 denotes a support member that supports the substrate 7 so as to be movable in a predetermined direction.
[0012]
Here, in the sputter power supply 4, 4 a is a 200 V commercial power supply of 50 Hz or 60 Hz, 4 b is a single-phase compound winding step-up transformer, and this transformer 4 b allows the single-phase AC signals from the commercial power supply to be in phase with each other. Two single-phase alternating currents differing by 180 degrees are connected, and the hold 3 of one target 2 is connected to one terminal of the transformer 4b, and the hold 3 of the other target 2 is connected to the other terminal. An alternating voltage that is 180 degrees out of phase is applied to the targets 2 and 2 that face each other.
[0013]
When sputtering is performed using the apparatus as described above to form a sputtered film on the substrate, the conditions are not particularly limited, and the reactive gas introduced into the type of metal target or target space using normal conditions A sputtered film can be formed according to the kind of the film, but the present invention is particularly suitable when a photocatalytic film is formed on a substrate.
[0014]
Here, when the photocatalytic film is formed on the substrate, the metal target to be used is a metal oxide MeO _x having a photocatalytic action (Me is Al, Co, Cu, Fe, In, Mg, Sn, Ti, Zn, etc.) X is a positive number in the range of 0 to 10, preferably 0 to 5, and x does not necessarily correspond to the valence of the metal. A metal corresponding to the metal oxide is selected, and titanium that forms a titanium oxide film is particularly preferable.
[0015]
After exhausting the inside of the vacuum chamber sufficiently, a gas containing an inert gas and oxygen molecules is introduced, and then the pressure in the chamber is kept at 0.1 to 100 mTorr, particularly 0.3 to 30 mTorr, and film formation is performed. Here, as the gas having an oxygen molecule (oxidizing gas) supplied to the sputtering space, a known gas can be used. Specifically, oxygen, ozone, air, water, and the like can be given. Usually oxygen is used. Moreover, helium, argon, etc. can be used as an inert gas, and especially industrially cheap argon can be used conveniently.
[0016]
【The invention's effect】
According to the present invention, a sputtering apparatus can be manufactured at a low cost, and thus a sputtered film can be manufactured at a low cost and at a high film formation rate.
[0017]
【Example】
EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.
[0018]
〔Example〕
Two titanium targets having a diameter of 100 mm were placed on each cathode using the facing target sputtering apparatus shown in FIG. A 0.1 mm-thick stainless steel plate (SUS304) was used as a substrate, degreased with acetone in advance, and then set in a vacuum apparatus. After evacuating the vacuum chamber, first, only argon gas is allowed to flow, high-frequency plasma treatment (100 W × 10 minutes) is performed in the chamber, argon gas is then flowed at a flow rate of 10 cc / min, and oxygen gas is flowed at a flow rate of 10 cc / min. An alternating voltage with a phase shift of 180 degrees at a film pressure of 5 mTorr was applied to each of the opposing targets, and a film was formed at an applied power of 1200 W for 60 minutes.
[0019]
In this case, a commercial 50 Hz, 200 V single-phase alternating current was boosted to 600 V by a single-phase compound winding step-up transformer, and two single-phase alternating current signals that were 180 degrees out of phase were obtained.
[0020]
As a result, the film formation rate was 300 mm / min when the film thickness was measured with a film thickness meter manufactured by Taylor Hobson, and the photocatalytic effect was about 0.1 mg / cm ² of machine oil on the film formed. After coating, a test piece was placed at a position of 15 cm under a 400 W low-pressure mercury lamp, and the oil decomposition rate was 95% as determined from the weight loss after irradiation for 3 hours.
[Brief description of the drawings]
FIG. 1 is a schematic view showing one embodiment of an opposed target sputtering apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Metal target 3 Hold 3a Support part 4 Sputtering power supply 4a Commercial power supply 4b Single phase compound winding step-up transformer 5 Magnet 6 Sputter space 7 Substrate 8 Support member

Claims (1)

  When a sputter film is formed by a counter-target sputtering method in which a substrate is disposed on the side of a sputter space between opposed titanium targets and a sputter film is formed on the substrate, a single-phase alternating current is boosted by a single-phase alternating current. While boosting with a transformer, AC signals that are 180 degrees out of phase with each other are formed, the AC voltages that are 180 degrees out of phase with each other are applied to the two titanium targets, and inert gas and oxygen molecules are introduced into the sputtering space. A method for producing a sputtered film, comprising introducing a gas having an anatase structure titanium oxide photocatalyst film on a substrate.

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