JPH07138761A - Method and apparatus for producing thin film - Google Patents

Abstract

PURPOSE:To form thin films of various kinds of multicomponent metal compds. on a substrate at a low cost by introducing raw materials for forming the thin films in the form of a soln. mist by a discharge gas consisting essentially of a rare gas into an atm. pressure glow discharge area and generating a plasma discharge. CONSTITUTION:A soln. 7 prepd. by dissolving compds. of various kinds of inorg. metals and org. metals into a solvent, such as water or alcohol, is supplied from a supply port 6 into a vessel 1 of a mist generating section (a) and inert gases, such as He, or reactive gases, of O2, etc., are introduced as a carrier gas from a gas introducing pipe 4. The soln. of a metallic compd. is misted by an ultrasonic vibrator, etc. The soln. is supplied together with the carrier gas from a connecting port 5 into a pipeline (b). The rare gas, such as He, is then incorporated from a supply port 15 into the mist-contg. gas in such a manner that the volume % thereof attains >=90%. The gaseous mixture is supplied as a discharge gas into a discharge pipe 17 and the glow discharge is generated under atm. pressure by impressing a voltage to an electrode 18 to generate plasma. The cap 22 of the discharge pipe 17 is removed and the high- quality thin films consisting of various kinds of the metal compds. are formed on the surface of the substrate 23 facing the discharge tube.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film manufacturing method and apparatus. More particularly, the present invention relates to a new thin film manufacturing method by atmospheric pressure glow discharge plasma and a device therefor, which is useful for forming a high quality, highly efficient, multi-component thin film.

[0002]

2. Description of the Related Art Conventionally, as a method for forming thin films of various metals, alloys, and compounds such as oxides, carbides, and nitrides, vacuum vapor deposition and sputtering for vapor phase vapor deposition in a vacuum system. , CVD, ion plating, plasma CVD and the like, plasma spraying and the like are known.

Of these, the method utilizing the vacuum and low pressure conditions,
Particularly, in the case of ion plating or plasma CVD, it is effective as a method capable of forming a high quality thin film, and is utilized in the manufacture of precision instruments, optical instruments, electronic devices, semiconductors and the like. However, in the conventional thin film formation by this vacuum low pressure method, equipment and maintenance for the vacuum system are required, and precision control is also required for the condition control for the thin film formation, and it is difficult to improve the efficiency. There was a drawback. Therefore, the cost was inevitably high.

On the other hand, since plasma spraying is carried out under atmospheric pressure conditions, the cost for a vacuum system is not required, but since it is spraying at an extremely high temperature, the target substance is naturally limited, and However, there is a drawback that it is difficult to precisely control the structure and composition of the thin film. Furthermore,
It is difficult to form a multi-component thin film such as a complex oxide in both the low pressure method and the thermal spraying method, and there is a drawback in this respect as well.

The present invention has been made in view of the above-mentioned circumstances, solves the drawbacks of the conventional method, enables the formation of a high quality and highly efficient thin film, and is capable of forming a multi-component thin film. It is an object of the present invention to provide a new thin film manufacturing method which can be easily formed and an apparatus therefor.

[0006]

In order to solve the above problems, the present invention provides a solution mist of an inorganic metal compound, an organic metal compound, or a mixture thereof with a rare gas, or a rare gas and an inert gas or a reaction. Disclosed is a method for producing a thin film by atmospheric pressure glow discharge, which comprises introducing a thin film containing a metal or a metal compound into a substrate surface by introducing the mixed gas with a reactive gas into an atmospheric pressure glow discharge region.

As a device therefor, the present invention provides a conduit for floating and carrying a solution mist of an inorganic metal compound, an organometallic compound or a mixture thereof, a cooler for collecting and collecting a solvent contained in the mist, and this pipe. A thin film forming apparatus by discharge having an electrode arranged in a path and a gas introduction portion and an open end portion facing the substrate, wherein a rare gas or a rare gas and an inert gas or a reactive gas is introduced from the gas introduction portion. An apparatus for producing a thin film by atmospheric pressure glow discharge, characterized in that a mixed gas is introduced, an atmospheric pressure glow discharge is generated by applying a voltage to an electrode, and a thin film is formed on a substrate surface facing an open end of a conduit. Will also be provided.

[0008]

That is, the present invention is an application of the glow discharge plasma technology under atmospheric pressure or higher pressure which the inventor has already proposed as opening up a new area of plasma technology. This atmospheric pressure plasma technology is based on the finding that glow discharge plasma is stably generated under conditions of atmospheric pressure or higher, which could not have been predicted from conventional technical common sense. The finding that glow discharge plasma can be stably generated without using low-pressure vacuum conditions and that it can be applied as an industrial technology has opened up a new dimension of plasma reaction technology.

It is also already proposed that there is thin film formation as one application of this new plasma technology. However, regarding the measures for maximizing the characteristics of utilizing the atmospheric pressure condition in its application aspect, the study is just under way.

The method of forming a thin film using the solution mist of the present invention was created from such a study process. In the method of the present invention, the raw material for forming a thin film is introduced into the atmospheric pressure glow discharge region as a solution mist. As the raw material at this time, various inorganic metal compounds and organometallic compounds are used. To be done. For example, various metals, metalloid halides, nitrates, sulfates, phosphates, carbonates, organic acid salts, metal chelate compounds, complex salts, alcoholates, and other appropriate inorganic or organic metal compounds are exemplified. .

These raw materials can be used by dissolving them in various solvents as long as they do not inhibit thin film formation. As the solvent in that case, water, alcohol, ether, ketone, and others are appropriately used. The solution mist can be formed, for example, by a means known as a nebulizer using ultrasonic waves or the like, and these mists are gas, more preferably a rare gas, or a mixed gas of a rare gas and an inert gas, or a reactive gas. To the discharge area.

Before introduction into the discharge region, it may be heated in advance. Further, as rare gas, He, N
Although e and the like are used, He is most preferably used. Of course, it may be a mixed rare gas. For example H
e + Ne, He + Ar and the like. It may be mixed with carbon dioxide gas or nitrogen gas as an inert gas, or further with a reactive gas. These are selected according to a predetermined thin film composition and its physical properties. For example, oxygen, hydrogen,
Nitrogen, hydrocarbons, ammonia, amines, fluorohydrocarbons,
Halogen etc. are illustrated. Generally, when using these inert and / or reactive gases,
It is preferable that the ratio of the rare gas is 90% by volume or more. Therefore, the ratio of the inert gas or the reactive gas is 10% or less. The pressure of the gas during film formation is
The pressure under the atmospheric pressure near the atmospheric pressure can be set to the atmospheric pressure or higher. This pressure and the flow rate of gas are sufficient to carry the solution mist in suspension, and
It may be appropriately selected so that stable discharge for thin film formation is performed.

Various conditions such as applied voltage for discharge, concentration of solution mist, residence time in discharge region, etc. are appropriately selected in accordance with known knowledge and target thin film. In any case, according to the present invention, it is possible to manufacture a thin film with high efficiency without requiring a vacuum system unlike the conventional vapor deposition, sputtering, plasma CVD, laser CVD and the like. It is easy to control the composition of the thin film. Since it is easy to prepare a highly pure raw material, it is also effective for forming a multi-component thin film.

According to the present invention, Al₂O₃, Si
O₂, ZnO, SnO₂, Fe₂O₃, AlN, Ti
Including N, SiC, ITO, etc.
BaTiO ₃, PbZr for optoelectronic materials
_xTi_1-xO₃, Piezoelectric material LiNbO₃Of pyroelectric materials
PbTiO₃, Varistor, ferrite, and various other things
A high quality thin film can be formed.

The present invention will be described in more detail below with reference to examples.

[0016]

1 is a block diagram showing an example of an apparatus for carrying out the present invention. The raw material is an aqueous solution, which is made into a mist by a nebulizer. This mist is introduced into the discharge area by a helium (He) gas through a conduit. The ribbon heater and the cooling pipe are for minimizing water content which is a solvent component of the raw material mist.

The atmospheric pressure glow discharge is generated by introducing helium (He) gas. And as the substrate, S
A ZnO thin film was formed using an aqueous mist of Zn (NO ₃ ) ₂ using i and glass, respectively. Table 1 shows the conditions for this.

[0018]

[Table 1]

As a result, the maximum film formation rate was obtained when the solution concentration was 0.01M. A ZnO thin film was selectively formed at a substrate temperature of 500 ° C. or higher. Powder formation was also observed at lower temperatures. The thin film formed at 600 ° C. or lower is a non-oriented ZnO film, and a C-axis oriented ZnO film.
Thin films were formed at higher substrate temperature conditions.

FIG. 2 shows the relationship between the substrate temperature and the film formation rate. Similarly, Fe ₂ O ₃ and Sn
It is also possible to form various thin films such as O ₂ and BaTiO ₃ .

[0021]

As described in detail above, according to the present invention, it is possible to easily prepare a high-purity raw material and form a thin film of high quality and high efficiency. In addition, it is easy to form a multi-component thin film.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of an apparatus of the present invention.

FIG. 2 is a relationship diagram between a substrate temperature and a ZnO film forming rate as an example.

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[Procedure amendment]

[Submission date] February 25, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Method and apparatus for manufacturing thin film

[Claims]

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film manufacturing method and apparatus. More particularly, the present invention relates to a new thin film manufacturing method by atmospheric pressure glow discharge plasma and a device therefor, which is useful for forming a high quality, highly efficient, multi-component thin film.

2. Description of the Related Art Conventionally, as a method for forming thin films of various metals, alloys, and compounds such as oxides, carbides, and nitrides, vacuum vapor deposition and sputtering for vapor phase vapor deposition in a vacuum system. , CVD, ion plating, plasma CVD and the like, plasma spraying and the like are known. Of these, the method utilizing the vacuum and low pressure conditions, especially ion plating and plasma C
In the case of VD, it is effective as a method capable of forming a high quality thin film, and is utilized in the manufacture of precision instruments, optical instruments, electronic devices, semiconductors and the like. However, in the conventional thin film formation by this vacuum low pressure method, equipment and maintenance for the vacuum system are required,
In addition, precision is required for the condition control for thin film formation,
Moreover, there is a drawback that it is difficult to improve efficiency. Therefore, the cost was inevitably high. On the other hand, plasma spraying is performed under atmospheric pressure conditions, so the cost for a vacuum system is not required, but since it is spraying at extremely high temperatures, the target substance is naturally limited, and the thin film There is a drawback that it is difficult to precisely control the structure and composition. Furthermore, it is difficult to form a multi-component thin film such as a complex oxide in both the low pressure method and the thermal spraying method, and there is a drawback in this respect as well. The present invention has been made in view of the above circumstances, eliminates the drawbacks of the conventional method, enables high-quality, highly-efficient thin film formation, and also enables formation of a multi-component thin film. It is an object of the present invention to provide a new thin film manufacturing method that can be easily performed and an apparatus therefor.

In order to solve the above problems, the present invention provides a solution mist of an inorganic metal compound, an organic metal compound or a mixture thereof with a rare gas or an inert gas or a reactive gas. Of at least one of the mixed gas is introduced into an atmospheric pressure glow discharge region by a discharge gas to form a metal or metal compound-containing thin film on the surface of the substrate, thereby producing a thin film by atmospheric pressure glow discharge. Provide a way. Further, the present invention, as a device therefor, a mist generating part for generating a mist of a solution of an inorganic metal compound, an organic metal compound or a mixture thereof, and a solution mist generated in the mist generating part, which is connected to the mist generating part. It has a pipeline for floating transportation and a main body having one end connected to this pipeline and an open end formed at the other end, and an electrode connected to a power source is wound around the outer periphery thereof, and At the end on the road side, a plasma is connected to a gas introduction part for introducing a discharge gas, which is a rare gas or a mixed gas of a rare gas and at least one of an inert gas and a reactive gas, into the main body. A thin film formed by atmospheric pressure glow discharge, characterized in that it comprises a generating part and a substrate supporting part having a substrate holder for disposing the substrate facing the open end of the plasma generating part main body. Also it provides a concrete apparatus.

[Operation] In other words, this invention is
We are proposing to open up new areas of Zuma technology.
Glow discharge plastic under atmospheric pressure or higher
It is an application of Zuma technology. This atmospheric plasma technique
The art is a big thing that couldn't have been predicted from the conventional technical common sense.
Glow discharge plasma is generated stably under atmospheric pressure
It was made based on the knowledge that. Low pressure vacuum strip
Stable generation of glow discharge plasma without adopting conditions
However, the knowledge that it can be applied as an industrial technology
Is a new genre of plasma reaction technology.
It was One application of this new plasma technology is thin film
That there is success is what we have already proposed. Was
However, the feature of using atmospheric pressure conditions is its application aspect.
For the measures to make the most of
The study is just under way. This invention
The method of thin film formation using the solution mist of
It was created from the process of discussion. In the method of this invention
In addition, the raw material for thin film formation is solution mist.
Are introduced into the atmospheric pressure glow discharge region, but the raw materials at this time
As an inorganic metal compound or an organic metal compound
Seeds are used. For example, various metals and metalloids
Rogenide, nitrate, sulfate, phosphate, carbonate, organic
Acid salts, metal chelate compounds, complex salts, alcoholates, etc.
Suitable examples of other inorganic or organic metal compounds
To be done. These can also be used as a mixture
It In addition, these raw materials do not hinder thin film formation.
If it is one, it can be dissolved in various solvents before use.
it can. The solvent used in this case is water, alcohol,
Tellers, ketones and others are used as appropriate. solution
The mist is, for example, a nebulizer using ultrasonic waves.
Can be formed as. This solution mist discharges
You may preheat it before introducing it into the area.
Yes. Noble gas or inert to noble gas as discharge gas
Mixture of at least one of gas and reactive gas
The mixed gas can be used. That is, rare
Simplex or mixture of gases, mixture of rare gas and inert gas
Substances, mixtures of rare gases and reactive gases, and
A mixture of an active gas and a reactive gas is exemplified. Rare
He, Ne, etc. are most preferably used as the gas.
Is used He. As a mixture of noble gases,
For example, He + Ne, He + Ar, etc. are illustrated. Inert gas
Examples of carbon dioxide, nitrogen gas, etc.
Examples of the gas include oxygen, hydrogen, nitrogen, hydrocarbons,
Examples include ammonia, amines, fluorohydrocarbons, halogens, etc.
Shown. These depend on the specified thin film composition and its physical properties.
Selected. Regarding gas components introduced into the discharge area
In general, considering the raw material mist,
It is preferable to make the ratio of 90% by volume or more
Good That is, the raw material mist or the inert gas and
Gas and / or reactive gas if these gases are used.
The total amount of the gas component and the raw material mist is 10% by volume or less.
It The gas pressure during film formation is the atmospheric pressure near atmospheric pressure.
To atmospheric pressure or higher. this
The pressure, and the flow rate of the gas, are guided to the discharge area of the solution mist.
Of stable glow discharge for injection and thin film formation
It may be selected as appropriate. Application for discharge
Various conditions such as voltage, concentration of solution mist and residence time in discharge area
The case corresponds to the known knowledge and the target thin film.
Is appropriately selected. In any case, according to this invention
Conventional evaporation, sputtering, plasma CVD,
Without the need for a vacuum system such as laser CVD
Thin film production with high efficiency is possible. Control of thin film composition
It's easy. Is it easy to prepare highly pure raw materials?
It is also effective for forming a multi-component thin film. According to this invention
Al₂O₃, SiO₂, ZnO, SnO₂, Fe
₂O₃, AlN, TiN, SiC, ITO, etc.,
For example, ferroelectric BaTiO 3 ₃, Optoelectro
Nix material PbZr_xTi_1-xO₃, Piezoelectric material Li
NbO₃, Non-electric material PbTiO₃, Barista, blow job
It is possible to form thin films of iron and other various substances. Since
Hereinafter, examples will be shown to explain the present invention in more detail.
To do.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram conceptually illustrating one embodiment of the thin film manufacturing apparatus of the present invention. As illustrated in FIG. 1, the thin film manufacturing apparatus is roughly divided into four parts, that is, a mist generating part (a), a conduit (a), a plasma generating part (c) and a substrate supporting part (d). It has the following configuration. In the mist generating section (a), a mist of a raw material solution of an inorganic metal compound, an organic metal compound or a mixture thereof is generated. The pipeline (a) is for transporting the raw material mist generated in the mist generating section (a) to the plasma generating section (c) in a floating state, and the pipeline (a) is for the mist generating section (a). A) and the plasma generator (c), respectively. A discharge gas composed of a rare gas or a mixed gas of at least one of an inert gas and a reactive gas is introduced into the plasma generation section (c),
These gases are excited to generate glow discharge at about atmospheric pressure. Then, the above-mentioned raw material mist is conveyed to this atmospheric pressure glow discharge region and is chemically activated. A substrate to be processed is placed on the substrate supporting portion (d), and the activated raw material mist from the plasma generating portion (c) is sprayed on the surface of the substrate to form a thin film. FIG. 2 is a perspective view showing an example of the mist generator (a) illustrated in FIG. In the example of FIG. 2, the ultrasonic vibrator (2) is provided at the bottom of the hollow spherical container (1).
A DC power source (3) is electrically connected to the ultrasonic transducer (2). At the upper part of the container (1), a carrier gas inlet (4) for introducing a carrier gas such as He, is shown in FIG.
A connection port (5) connected to the pipe (a) exemplified in 1. and a supply port (6) for a raw material solution of an inorganic metal compound, an organic metal compound or a mixture thereof are provided. The raw material solution (7) is introduced into the container (1) through the raw material supply port (6). In such a mist generating section (a), after the raw material solution (7) is introduced into the container (1) through the raw material supply port (6), the DC power source (3) is turned on and the ultrasonic transducer (2) is turned on. While operating, the carrier gas such as He is introduced into the container (1) through the carrier gas inlet (4) to generate a fine mist of the raw material solution (7), which is accompanied by the flow of the carrier gas. While the mist floats, it flows out from the connection port (5) toward the conduit (a) illustrated in FIG. As the carrier gas for transporting the raw material mist while suspending it, the same gas component as that of the discharge gas can be used. That is, it can be a rare gas or a mixed gas of a rare gas and at least one of an inert gas and a reactive gas. These gas components are also appropriately selected according to a predetermined thin film composition and its physical properties. As illustrated in FIG. 1, the carrier gas inlet (4)
Can be equipped with a flow meter (8) for controlling the flow rate of the carrier gas. Further, a ribbon heater (9) can be provided at the introduction portion from the connection port (5) to the conduit (a). The ribbon heater (9) is for heating the raw material mist carried by the carrier gas. In the apparatus for producing a thin film of the present invention, in addition to the mist generating section illustrated in FIG. 2 as the mist generating section (a), an appropriate one such as a compressed gas or a rotating disk may be used. It is also possible to adopt. Further, as illustrated in FIG. 1, a cooling pipe (10) is connected to the pipe line (a). This cooling pipe (10)
Together with the ribbon heater (9) described above, it is for reducing the amount of water content in the raw material mist. When the water content increases, the atmospheric pressure glow discharge plasma in the plasma generating part (c) is likely to become unstable. A container (11) for receiving the removed excess water and the like is connected to the end of the conduit (a) on the side opposite to the plasma generating part (c), and the trap ( 12) is connected via a cock (13). Excessive gas components and the like can be exhausted to the outside via this trap (12). On the other hand, another cock (14) is connected between the conduit (a) and the plasma generation part (c), and the gas introduction part (1) for introducing the discharge gas is introduced.
5) is provided. From this gas introduction part (15),
Discharge gas can be introduced into the plasma generating part (c). The gas introduction part (15) can be provided with a flow meter (16) for controlling the gas flow rate. FIG. 3 shows FIG.
It is a perspective view showing an example of a plasma generation part (c) and a substrate support part (d) illustrated in FIG. In the example of FIG. 3, the plasma generator (c) includes a cylindrical discharge tube (17) as a main body. The lower end of the discharge tube (17) is connected to the conduit (a) illustrated in FIG. 1, and the upper end has an open end that opens upward. Further, two copper plate electrodes (18) as electrodes are wound around the outer circumference of the discharge tube (17), and these copper plate electrodes (18) are electrically connected to an RF power source of 13.56 MHz and maximum output of 500 W, for example. You can The type of electrode is not limited to the copper plate, and any other appropriate type can be adopted. Inside such a discharge tube (17),
The discharge gas is introduced from the gas introduction part (15).
A quartz tube, for example, can be used as the discharge tube (17). The discharge tube (17) may be integrated with the conduit (a). Further, the plasma generating part (c) is provided with a hollow electrode protection tube (19) outside the discharge tube (17), and the discharge tube (1) is provided inside the electrode protection tube (19).
7) is stored. The electrode protection tube (19) has an opening for inserting the discharge tube (17) into the lower end surface thereof,
The lower side surface also has a gas introduction port (20) and an exhaust port (21) facing it. A hollow cap (22) is provided at the upper end. From the gas inlet (20) of the electrode protection tube (19), the discharge tube (17)
Electrodes such as copper plate electrodes (18) wrapped around the outer periphery of
It is possible to introduce a gas component for preventing oxidation due to heating accompanying generation of atmospheric pressure glow discharge plasma. Electrodes such as the copper plate electrode (18) are heated by the generation of atmospheric pressure glow discharge plasma, and are easily oxidized.
When the electrode oxidation occurs in this way, the atmospheric pressure glow discharge plasma becomes unstable. In order to prevent this, a gas that suppresses oxidation is introduced from the gas introduction port (20) of the electrode protection tube (19). The gas component is not particularly limited as long as it has the property of suppressing electrode oxidation, and N ₂ can be exemplified. The gas component introduced into the electrode protection tube (19) is supplied from the exhaust port (21) to the electrode protection tube (19).
Is discharged to the outside. As such an electrode protection tube (19), for example, a glass tube can be used. In order to prevent the copper plate electrode (18) and other electrodes from being oxidized, the entire electrode is wrapped with, for example, glass tape,
And you may make it accommodate in the said electrode protection tube (19). In such a plasma generation unit (c), a discharge gas is introduced from the gas introduction unit (15) and RF power is applied to the copper plate electrode (18), so that stable glow discharge plasma can be generated at about atmospheric pressure. To generate. Further, in the example of FIG. 3, the discharge tube (17) of the plasma generator (c) is used.
The substrate supporting part (d) is provided with a hollow substrate holder (24) so that the substrate (23) can be arranged so as to face the upper open end of the substrate. The substrate (23) is arranged on the upper surface of the substrate holder (24) and faces the open end of the discharge tube (17) through the opening of the substrate holder (24). The substrate holder (24) may be provided with a reaction gas introduction tube so that the reactive gas can be directly sprayed onto the substrate (23), if necessary. In addition, a heating plate (25) for uniformly heating the substrate (23) is provided on the substrate (23). Inside the heating plate (25), the substrate (2
A thermocouple (26) for temperature measurement of 3) is provided,
It is electrically connected to the temperature measuring device (27). The material of the heating plate (25) is not particularly limited, and may be, for example, a quartz plate or the like. An IR heater (2) is provided on the heating plate (25) as a means for heating the substrate (23).
8) is provided. Further, in the example of FIG. 3, the plasma generating section (c) and the IR heater (2
The substrate supporting part (d) excluding 8) is also housed in the case body (29). The hinge (3
0) is provided with a door (31) which is connected to the side surface and is rotatable. The discharge tube (17) is arranged and fixed inside the case body (29) by the fixing arm (32) together with the electrode protection tube (19). An opening (33) that allows the substrate holder (24) to move up and down is formed on the back surface of the case body (29) facing the door (31). A fixed arm (34) is connected to the rear of the substrate holder (24), and the fixed arm (3
4) is inserted into the opening (33) provided on the back surface of the case body (29), the substrate holder (24) can be moved up and down within a predetermined height range, and the substrate can be fixed at an appropriate position. I am trying. A lid (36) having a heating plate (35) such as a quartz plate at the center is provided on the upper surface of the case body (29). The above-mentioned IR heater (28) is arranged above the heating plate (35) of the lid (36). That is, the heating of the substrate (23) is performed by the infrared rays emitted from the IR heater (23).
5) (25). on the other hand,
An exhaust port (37) is formed on the lower surface of the case body (29) so that it can be connected to a drafter or the like for forced exhaust. A gas component such as N ₂ exhausted from the exhaust port (21) of the electrode protection tube (19) can be exhausted to the outside from the case body (29). Preparation of Thin Film For example, using an apparatus as shown in FIGS. 1, 2 and 3, an aqueous solution of zinc nitrate [Zn (NO ₃ ) ₂ ] was used as a raw material solution, and the conditions as shown in Table 1 below were used. Plate electrode (18) wrapped around the outer circumference of the discharge tube (17) in
RF power was applied to the inside of the discharge tube (17) to generate atmospheric pressure glow discharge plasma, and the Zn (NO ₃ ) ₂ aqueous solution mist generated in the mist generating section (a) was introduced into this plasma region. . Then, an attempt was made to form a thin film on each of the glass slide, the quartz plate, and the silicon wafer.

[Table 1] He gas was used as the carrier gas and the discharge gas when the mist of the Zn (NO ₃ ) ₂ aqueous solution was generated and the atmospheric pressure glow discharge plasma was generated. Further, in order to improve the stability of the atmospheric pressure glow discharge plasma,
The flow rate ratio (Fc / Fd) of carrier gas and discharge gas was set to 0.1 or less. As a result, a thin film was selectively formed at a substrate temperature of 500 ° C or higher, and a mixture of the thin film and powder was formed at a substrate temperature of lower than 500 ° C. 4 a, b and c
Are set to a substrate temperature of 250 ± 10 ° C., a Zn (NO ₃ ) ₂ aqueous solution concentration (C) of 0.01 M, and a flow rate ratio (Fc / Fd) of 0.1 / 1.0, respectively, and the distance between the discharge tube opening end and the substrate (D ) 2 each
It is a scanning electron microscope (SEM) photograph of the substrate surface obtained at 0 mm, 10 mm and 5 mm. Further, a, b, c and d in FIG. 5 are C = 0.01M and Fc / Fd = 0.1, respectively.
Set the substrate temperature to 720, 680, 63 by setting /1.0 and D = 5mm.
SE of the substrate surface of the sample obtained at 0 and 550 ° C
It is an M photograph. As is apparent from FIGS. 4 and 5, the substrate has a substantially uniform surface, and
The particle size of the powder and the particles adhered in the form of a film was about 1 μm. Further, the formed thin film was identified by using an X-ray diffractometer (XRD). FIG. 6 shows an example of the result. As is clear from FIG. 6, it was confirmed that the film attached to the substrate surface was zinc oxide (ZnO). It was also confirmed that the peak of the (002) plane became stronger as the substrate temperature increased. FIG. 7 is a correlation diagram in which the ratio of the peak intensity of the obtained ZnO film is plotted against the substrate temperature. The ZnO film is
It is known to be oriented in the (002) plane direction. As is clear from FIG. 7, the obtained ZnO film has
It was found that the orientation gradually increased from the substrate temperature around 630 ° C, reached the maximum at about 680 ° C, and then decreased. Furthermore, a rocking curve was measured for the orientation of this ZnO film. Examples of the results are shown in FIGS. 8A and 8B. As is clear from FIGS. 8A and 8B, it was confirmed that the half-width (σ) becomes smaller as the substrate temperature becomes higher, and the C-axis orientation becomes higher. It was also confirmed that the deviation (m) from the center line to the rocking curve peak was almost constant regardless of the substrate temperature, and was oriented perpendicular to the substrate. Furthermore, the obtained ZnO film was measured for UV-visible absorption spectrum to calculate the optical band gap. FIG. 9 shows the result. For this measurement, a ZnO film (substrate temperature 550 ° C) formed on a quartz substrate was used.
And 630 ° C.) were used. As is clear from FIG. 9, the optical bandgap is 3.30 eV and the bulk bandgap is 3.20 eV. Therefore, it was confirmed that the ZnO film containing almost no impurities was formed. . 10 and 11 show Fc / Fd = 0.1 /, respectively.
FIG. 3 is a correlation diagram showing the relationship between the film formation rate of a ZnO film formed by using an aqueous Zn (NO ₃ ) ₂ solution prepared to each concentration (C) with 1.0 and D = 5 mm and the substrate temperature. For the samples of C = 0.1 and 1.0M, a curve that substantially matches the curve shown in FIG.
The film formation rate became maximum at around ℃. On the other hand, for the sample of C = 0.01 M, as shown in FIG. 11, the film formation rate increased as compared with the case of other concentrations. Further, as illustrated in FIG. 10, the thin film was not formed at the substrate temperature of 300 ° C. This is because the ZnO powder causes desorption of oxygen at about 300 ° C., and the thermal energy of the substrate causes this reaction. It can be considered that the etching rate of the plasma used or the rate of heterogeneous nucleation on the substrate became almost the same. In the same manner as above, Fe ₂ O ₃ , SnO ₂ , Ba
It is possible to form various thin films such as TiO ₃ . Of course, the present invention is not limited to the above examples. Needless to say, various modes are possible for the detailed structure of the device, the reaction conditions, and the like.

As described in detail above, according to the present invention, it is possible to easily prepare a high-purity raw material and form a thin film of high quality and high efficiency. In addition, it is easy to form a multi-component thin film.

[Brief description of drawings]

FIG. 1 is a configuration diagram conceptually illustrating an embodiment of a thin film manufacturing apparatus of the present invention.

FIG. 2 is a perspective view showing an example of the mist generating section illustrated in FIG.

FIG. 3 is a perspective view showing an example of a plasma generation unit and a substrate support unit illustrated in FIG.

FIG. 4 a, b and c are each a substrate temperature of 250 ± 10.
℃, Zn (NO ₃ ) ₂ aqueous solution concentration (C) 0.01M and flow rate ratio (Fc / Fd) 0.1 / 1.0 were set, and the distance (D) between the discharge tube opening end and the substrate was set to 20 mm, 10 mm and 5 mm, respectively. It is a scanning electron micrograph of the substrate surface obtained at the time of doing as a drawing substitute.

FIG. 5 a, b, c and d are C = 0.01M and Fc, respectively.
/Fd=0.1/1.0 and D = 5mm, and the substrate temperature is 72
It is a scanning electron microscope photograph as a drawing substitute of the substrate surface obtained at 0, 680, 630 and 550 ° C.

FIG. 6 is a diffraction peak diagram showing an example of diffraction peaks obtained by an X-ray diffractometer.

FIG. 7 is a correlation diagram in which the ratio of the peak intensity of the ZnO film is plotted against the substrate temperature.

8A and 8B are distribution charts each showing an example of a rocking curve for a ZnO film.

FIG. 9 is a correlation diagram showing the relationship between the photon energy and the square of the extinction coefficient for a ZnO film.

FIG. 10 is a correlation diagram showing the relationship between the deposition rate of a ZnO film and the substrate temperature.

FIG. 11 is a correlation diagram showing the relationship between the deposition rate of a ZnO film and the substrate temperature.

[Explanation of symbols] Amist generation part a Pipe line c Plasma generation part d Substrate support part 1 Container 2 Ultrasonic vibrator 3 DC power supply 4 Carrier gas inlet port 5 Connection port 6 Raw material solution supply port 7 Raw material solution 8 Flowmeter 9 Ribbon heater 10 Cooling tube 11 Container 12 Trap 13 Cock 14 Cock 15 Gas introduction part 16 Flowmeter 17 Discharge tube 18 Copper plate electrode 19 Electrode protection tube 20 Gas introduction port 21 Exhaust port 22 Cap 23 Substrate 24 Substrate holder 25 Heating plate 26 Thermocouple 27 Temperature Measuring Instrument 28 IR Heater 29 Case Body 30 Hinge 31 Door 32 Fixed Arm 33 Opening 34 Fixed Arm 35 Heating Plate 36 Lid 37 Exhaust Port

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Claims (3)

[Claims] 1. A substrate surface is prepared by introducing a solution mist of an inorganic metal compound, an organic metal compound or a mixture thereof into an atmospheric pressure glow discharge region of a rare gas or a mixed gas of a rare gas and an inert gas or a reactive gas. A method of manufacturing a thin film by atmospheric pressure glow discharge, which comprises forming a thin film containing a metal or a metal compound on the substrate. 2. The surface treatment method according to claim 1, wherein the rare gas concentration is 90% or more of the mixed gas. 3. A discharge having a conduit for floating and carrying a solution mist of an inorganic metal compound, an organometallic compound or a mixture thereof, an electrode and a gas introduction portion arranged in this conduit, and an open end facing the substrate. A thin film manufacturing apparatus, in which a rare gas or a mixed gas of a rare gas and a reactive gas is introduced from a gas introduction part, and an atmospheric pressure glow discharge is generated by applying a voltage to an electrode, and an open end part of a pipeline is formed. An apparatus for producing a thin film by atmospheric pressure glow discharge, which comprises forming a thin film on the surface of a substrate facing the substrate.