JP2007182605A - Method for forming thin film, and thin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a thin film, by which a uniform thin film having high performance can be efficiently formed even at ordinary temperature, and to provide the thin film obtained by the same. <P>SOLUTION: The method for forming the thin film comprises imparting nanoparticle on a base material and subjecting the nanoparticle imparted on the base material to an atmospheric pressure plasma treatment. The atmospheric pressure plasma treatment is characterized by supplying a gas between opposing electrodes under atmospheric pressure or a pressure close to the atmospheric pressure, converting the gas into an excited gas by generating a high frequency electric field between the electrodes, and then exposing the nanoparticle imparted on the base material to the excited gas. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a novel thin film forming method and a thin film obtained thereby.

  Functional thin films, such as electrode films, dielectric protective films, semiconductor films, transparent conductive films, electrochromic films, fluorescent films, superconducting films, dielectric films, solar cell films, antireflection films, wear resistant films, optics Interference film, reflection film, antistatic film, conductive film, antifouling film, hard coat film, undercoat film, barrier film, electromagnetic wave shielding film, infrared shielding film, ultraviolet absorbing film, lubricating film, shape memory film, magnetic recording film There is a need for a method for producing a light-emitting element film, a biocompatible film, a corrosion-resistant film, a catalyst film, a gas sensor film, a decorative film, and the like with high performance and low cost.

  Conventionally, as a method for forming such a high-functional thin film, for example, it is formed by a wet film forming method typified by a coating method, or a vacuum film forming method such as a sputtering method, a vacuum evaporation method, or an ion plating method. However, it was difficult to achieve both the performance obtained and the cost of equipment. In contrast to the above method, it has been proposed by WO 02/48428, JP-A-2004-68143, etc. that these can be achieved by a thin film forming method using an atmospheric pressure plasma method.

On the other hand, a method of forming a high-performance transparent conductive film by applying a colloidal dispersant containing metal nanoparticles to a base material and baking it is disclosed (see Patent Document 1). In order to obtain a high-performance transparent conductive film, a high firing temperature of about 500 ° C. is required, and there is a problem that applicable substrates are limited to heat resistant materials. Also disclosed is a method of forming a high-performance transparent conductive film without applying a colloidal dispersant containing metal nanoparticles to a base material, drying, and baking by laser irradiation to warm the base material ( Patent Document 2). However, in this method, since it is necessary to scan the laser beam, it takes time for the laser irradiation, the production efficiency is poor, and the uniformity of the formed thin film is inferior.
JP 2003-249131 A JP 2003-249123 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a thin film forming method capable of forming a high performance and uniform thin film efficiently and at room temperature, and a thin film obtained thereby. is there.

  The above object of the present invention is achieved by the following configurations.

  1. A method of forming a thin film by applying nanoparticles to a substrate and subjecting the nanoparticles applied on the substrate to an atmospheric pressure plasma treatment, wherein the atmospheric pressure plasma treatment is performed at atmospheric pressure or atmospheric pressure. Under a pressure close to atmospheric pressure, a gas is supplied between opposing electrodes, and a high-frequency electric field is generated between the electrodes to make the gas an excitation gas, and the nanoparticles applied on the substrate to the excitation gas A method for forming a thin film, characterized by being a treatment for exposure.

  2. 2. The method for forming a thin film as described in 1 above, wherein the gas contains nitrogen.

  3. 3. The method for forming a thin film according to 1 or 2, wherein the average particle diameter of the nanoparticles is 1 nm or more and 20 nm or less.

  4). 4. The method for forming a thin film according to any one of 1 to 3, wherein the nanoparticles are metal atom-containing compounds.

  5. 5. The method for forming a thin film as described in 4 above, wherein the metal atom of the metal atom-containing compound is at least one selected from the group consisting of In, Ga, Al, Sn, Ge, Sb, Bi and Zn.

  6). The thin film forming method according to any one of 1 to 5, wherein the base material is a resin film.

  7). 7. The method for forming a thin film according to any one of 1 to 6, wherein the substrate is subjected to atmospheric pressure plasma treatment by being disposed between electrodes.

  8). A method of forming a thin film by subjecting nanoparticles to atmospheric pressure plasma treatment and applying the atmospheric pressure plasma treated nanoparticles onto a substrate, wherein the atmospheric pressure plasma treatment is performed at or near atmospheric pressure. The gas is supplied between opposing electrodes under the pressure of the gas, and a high-frequency electric field is generated between the electrodes to make the gas an excitation gas, and the nanoparticle is exposed to the excitation gas. Thin film forming method.

  9. 9. The method for forming a thin film as described in 8 above, wherein the gas contains nitrogen.

  10. 10. The method for forming a thin film as described in 8 or 9, wherein an average particle size of the nanoparticles is 1 nm or more and 20 nm or less.

  11. 11. The method for forming a thin film according to any one of 8 to 10, wherein the nanoparticles are a metal atom-containing compound.

  12 12. The method of forming a thin film as described in 11 above, wherein the metal atom of the metal atom-containing compound is at least one selected from the group consisting of In, Ga, Al, Sn, Ge, Sb, Bi and Zn.

  13. The thin film forming method according to any one of 8 to 12, wherein the base material is a resin film.

  14 14. The method for forming a thin film according to any one of 8 to 13, wherein the substrate is subjected to atmospheric pressure plasma treatment by being disposed between electrodes.

  15. A thin film formed by the thin film forming method according to any one of 1 to 14 above.

  ADVANTAGE OF THE INVENTION According to this invention, the thin film formation method which can form a highly efficient and uniform thin film efficiently also at normal temperature can be provided.

  As a result of intensive studies, the present inventor has provided a nanoparticle on a base material, and a thin film forming method in which the nanoparticle is subjected to atmospheric pressure plasma treatment by a specific method, whereby a high-performance and uniform thin film can be efficiently and It has been found that a thin film forming method can be obtained that can be formed even near room temperature.

  In addition, a high-performance, uniform thin film can be efficiently and even near room temperature by a thin film formation method in which nanoparticles are subjected to atmospheric pressure plasma treatment by a specific method, and nanoparticles subjected to atmospheric pressure plasma treatment are applied onto a substrate. It has been found that a thin film forming method that can be formed is obtained.

  Hereinafter, the present invention will be described in detail.

[Atmospheric pressure plasma treatment]
In the present invention, atmospheric pressure plasma treatment means that gas is supplied as an excitation gas by supplying a gas between opposing electrodes under a pressure at or near atmospheric pressure and generating a high-frequency electric field between the electrodes. This is a treatment of exposing nanoparticles to the excitation gas. This activates the nanoparticles and forms a thin film on the substrate.

  For the electrode used for atmospheric pressure plasma treatment, the gas supplied between the electrodes, the method for generating a high-frequency electric field, etc., the methods described in WO 02/48428 pamphlet and JP-A-2004-68143 can be applied. .

  The atmospheric pressure or the pressure under the pressure in the vicinity of the present invention is about 20 to 110 kPa, and preferably 93 to 104 kPa.

  The electrode is preferably a metal base material coated with a dielectric. It is preferable to coat a dielectric on at least one side of the opposed application electrode and the ground electrode, and more preferably coat both of the opposed application electrode and the ground electrode with a dielectric. The dielectric is preferably an inorganic substance having a relative dielectric constant of 6 to 45. Examples of such a dielectric include ceramics such as alumina and silicon nitride, silicate glass, and borate. Examples thereof include glass lining materials such as glass.

  In the present invention, the gas supplied between the electrodes contains at least a discharge gas. The discharge gas is a gas that can cause discharge by applying a voltage. Examples of the discharge gas include nitrogen, rare gas, air, hydrogen gas, oxygen, and the like. These may be used alone as a discharge gas or may be mixed. In the present invention, nitrogen is preferable as the discharge gas, and 50 to 100% by volume of the discharge gas is preferably nitrogen gas. At this time, as the discharge gas other than nitrogen, it is preferable to contain a rare gas of less than 50% by volume. Moreover, it is preferable to contain 90-99.9 volume% of quantity of discharge gas with respect to the total gas quantity supplied to discharge space.

  In addition to the discharge gas, the gas supplied between the electrodes may contain an additive gas that promotes the reaction for forming a thin film. Examples of the additive gas include oxygen, ozone, hydrogen peroxide, carbon dioxide, carbon monoxide, hydrogen, ammonia and the like, but oxygen, carbon monoxide and hydrogen are preferable, and components selected from these are mixed. It is preferable to do so. The content is preferably 0.01 to 5% by volume based on the total amount of gas, whereby the reaction is promoted and a dense and high-quality thin film can be formed.

  The gas supplied between the electrodes is activated by itself as a excitation gas when a voltage is applied thereto. And when the nanoparticle comprised from the metal atom containing compound which concerns on this invention is exposed to the said excitation gas, it will be estimated that the said gas changes to the state which can form a thin film on a base material.

  The high-frequency electric field generated between the electrodes may be an intermittent pulse wave or a continuous sine wave. However, in order to obtain a high effect of the present invention, it may be a continuous sine wave. preferable.

The frequency of the high frequency electric field is preferably 100 to 150 MHz. The power density supplied to the electrodes is preferably 1.0 W / cm ² or more, the upper limit is preferably 50 W / cm ² or less, more preferably 20W / cm ² or less.

  In addition, when the gas supplied between electrodes contains nitrogen as discharge gas, since a big electric field intensity | strength of a discharge start is required, it is preferable to superimpose two types of high frequency electric fields. In this way, even if the discharge gas is nitrogen, high-density plasma can be generated, a high-quality thin film can be formed at high speed, and it can be operated inexpensively and safely, and the environmental load is reduced. Reduction can also be achieved. The two kinds of high-frequency electric fields can maintain a stable discharge state by satisfying the following relationship.

That is, the first than the frequency omega ₁ of the high frequency electric field of the second high-frequency electric field frequency omega ₂ is high and the first strength V ₁ of the high-frequency electric field, strength V ₂ and the second high-frequency electric field The relationship with the intensity IV of the discharge start electric field is that V ₁ ≧ IV> V ₂ or V ₁ > IV ≧ V ₂ is satisfied. Here, the frequency of the first high-frequency electric field is preferably 200 kHz or less. The lower limit is preferably about 1 kHz. On the other hand, the frequency of the second high frequency electric field is preferably 800 kHz or more. The higher the frequency of the second high-frequency electric field, the higher the plasma density, and a dense and high-quality thin film can be obtained. The upper limit is preferably about 200 MHz.

  In this way, in the electric field generated between the electrodes, the nanoparticles composed of the metal atom-containing compound applied to the substrate or the nanoparticles before being applied to the substrate are exposed and activated, Reduce the film thickness.

[Nanoparticles]
In the thin film forming method of the present invention, nanoparticles are used as a thin film forming material. The nanoparticle is a metal nanoparticle containing one or more kinds of metal elements. A metal nanoparticle containing one type of metal element is a metal nanoparticle containing a single element metal containing one type of metal element and a metal element-containing compound containing one type of metal element in one particle. The nanoparticle containing two or more kinds of metal elements is a composite metal nanoparticle containing all of the metal elements in one particle, or a mixture of metal nanoparticles containing part or all of two or more kinds of metals in different particles. Or a mixture of the composite metal nanoparticles and the metal nanoparticles containing the one kind of metal element (hereinafter referred to as “nanoparticles” is used in the concept including all the above-mentioned embodiments). Among these, it is preferable to use composite metal nanoparticles.

  In the present invention, the composite metal nanoparticles include any form in which a plurality of metal species constitute the particles. A plurality of metal species may exist in an interaction with each other or may exist independently. Specifically, a solid solution, a eutectic, a compound or a state in which they coexist, a core A shell structure, just a heterogeneous mixture aspect is included. In addition, the nanoparticles need only have a portion where the metal is exposed on the surface. For example, even if a portion of the surface is oxidized or hydroxylated, the effect can be obtained if the metal portion remains. is there.

  In the present invention, the average particle diameter of the nanoparticles is preferably 1 nm or more and 20 nm. If the average particle diameter of the nanoparticles exceeds 20 nm, a large amount of energy is required to crystallize the particles, and if it is less than 1 nm, the particles tend to be unstable. The average particle diameter of the nanoparticles used in the present invention is more preferably 1 nm or more and 10 nm or less. In addition, so-called monodispersed particles are preferable because they utilize the expression of various particle size effects. In the present invention, the monodisperse particles have a coefficient of variation of preferably 30% or less, more preferably 20% or less, and still more preferably 10% or less.

(Metal atom-containing compound)
As a structure of the nanoparticle which concerns on this invention, a metal atom containing compound is preferable. As a metal atom containing compound which comprises the nanoparticle which concerns on this invention, a metal salt, a metal oxide, an organometallic compound, a halogen metal compound, a metal hydrogen compound etc. can be mentioned. The metal salt is preferably nitrate. Two or more kinds of metal element-containing compounds may be used. Specific examples include InSn, InZn, ZnSn, SbSn, and ZnInSn.

  Metals of metal salts, metal oxides, organometallic compounds, halogen metal compounds, metal hydrides include Li, Be, B, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn Fe, Co, Ni, Cu, Zn, Ga, Ge, Rb, Sr, Y, Zr, Nb, Mo, Cd, In, Ir, Sn, Sb, Cs, Ba, La, Hf, Ta, W, Tl , Pb, Bi, Ce, Pr, Nd, Pm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and the like.

  Examples of the organometallic compound include those represented by the following general formula (I).

Formula (I)
R _1x MR _2y R _3z
In the above general formula (I), M is a metal, R ₁ is an alkyl group, R ₂ is an alkoxy group, R ₃ is a β-diketone complex group, a β-ketocarboxylic acid ester complex group, a β-ketocarboxylic acid complex group, and a ketooxy group. It is a group selected from (ketooxy complex group), and when the valence of the metal M is m, x + y + z = m, x = 0 to m, or x = 0 to m−1, and y = 0 to 0. m and z = 0 to m, each of which is 0 or a positive integer. Examples of the alkyl group for R ₁ include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the alkoxy group for R ₂ include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a 3,3,3-trifluoropropoxy group. Further, a hydrogen atom in the alkyl group may be substituted with a fluorine atom. Examples of the group selected from the β-diketone complex group, β-ketocarboxylic acid ester complex group, β-ketocarboxylic acid complex group and ketooxy group (ketooxy complex group) of R ₃ include, for example, 2,4 -Pentanedione (also called acetylacetone or acetoacetone), 1,1,1,5,5,5-hexamethyl-2,4-pentanedione, 2,2,6,6-tetramethyl-3,5-heptanedione , 1,1,1-trifluoro-2,4-pentanedione, and the β-ketocarboxylic acid ester complex group includes, for example, acetoacetic acid methyl ester, acetoacetic acid ethyl ester, acetoacetic acid propyl ester, trimethyl Examples thereof include ethyl acetoacetate and methyl trifluoroacetoacetate. Eg to acetoacetate, there may be mentioned trimethyl acetoacetate, and as Ketookishi, for example, can be exemplified acetoxy group (or an acetoxy group), a propionyloxy group, Buchirirokishi group, acryloyloxy group, a methacryloyloxy group. These groups preferably have 18 or less carbon atoms. Further, it may be linear or branched, or a hydrogen atom substituted with a fluorine atom. Among the organometallic compounds, those having at least one oxygen in the molecule are preferable. As such, an organometallic compound containing at least one alkoxy group of R ₂ , a β-diketone complex group, a β-ketocarboxylic acid ester complex group, a β-ketocarboxylic acid complex group and a ketooxy group (ketooxy group) of R ₃ A metal compound having at least one group selected from (complex group) is preferred.

(Thin film formed)
The metal atom containing compound which comprises the nanoparticle which concerns on this invention can be suitably selected according to the kind of thin film to form. Although the example of the thin film formed below is shown, it is not restricted to this.

Electrode film: Au, Al, Ag, Ti, Ti, Pt, Mo, Mo-Si
Dielectric protective film: SiO ₂ , SiO, Si ₃ N ₄ , Al ₂ O ₃ , Al ₂ O ₃ , Y ₂ O ₃
Transparent conductive film: In ₂ O ₃ , SnO ₂
Electrochromic film: WO ₃ , IrO ₂ , MoO ₃ , V ₂ O ₅
Fluorescent film: ZnS, ZnS + ZnSe, ZnS + CdS
Magnetic recording film: Fe—Ni, Fe—Si—Al, γ-Fe ₂ O ₃ , Co, Fe ₃ O ₄ , Cr, SiO ₂ , AlO ₃
Super conductive film: Nb, Nb-Ge, NbN
Solar cell film: a-Si, Si
Reflective film: Ag, Al, Au, Cu
Selective absorption membrane: ZrC-Zr
Selective permeable membrane: In ₂ O ₃ , SnO ₂
Antireflection film: SiO ₂ , TiO ₂ , SnO ₂
Shadow mask: Cr
Abrasion resistant film: Cr, Ta, Pt, TiC, TiN
Corrosion resistant film: Al, Zn, Cd, Ta, Ti, Cr
Heat-resistant film: W, Ta, Ti
Lubricating film: MoS ₂
Decorative film: Cr, Al, Ag, Au, TiC, Cu
The nitridation degree of the nitride, the oxidation degree of the oxide, the sulfide degree of the sulfide, and the carbonization degree of the carbide are merely examples, and the composition ratio with the metal may be changed as appropriate. In addition to the metal compound, the thin film may contain impurities such as a carbon compound, a nitrogen compound, and a hydrogen compound.

(Nanoparticle application method)
In the present invention, the nanoparticles are applied on the substrate or directly supplied into the electric field between the electrodes.

  The method of applying nanoparticles on a substrate is a method of applying a dispersion containing nanoparticles as a coating film by coating such as dipping, spin coating, bar coating, roll coating, or applying as a droplet by spraying or the like. There is. Moreover, you may provide a nanoparticle as a powder to a base material. It is preferable to apply the droplets by spraying or the like. It is more preferable that the spray device has smaller droplets. Moreover, when supplying directly in an electric field, it supplies as a droplet.

<Preparation method of nanoparticle-containing coating solution>
A method for preparing nanoparticles and a method for preparing a dispersion containing nanoparticles are shown below.

  Nanoparticles can be synthesized by a liquid phase method or a gas phase method, and examples of synthesis of the liquid phase method are shown below. Metal hydroxide nanoparticles and metal carbonate nanoparticles can be used for inorganic salts such as halides, sulfates and nitrates of the metals, or organic acid salts such as acetates, oxalates, and tartrate salts. Dissolved in hydrophilic solvent, such as lithium hydroxide, sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, guanidine carbonate, aqueous ammonia, etc. It can be obtained by the action of alkali. The synthesis conditions vary depending on the compound type and can be set widely, but the temperature is preferably -20 to 95 ° C, the reaction time is 10 seconds to 3 hours, and the pH is preferably 3 to 11. The metal oxide nanoparticles can be obtained by heating and dehydrating the metal hydroxide nanoparticles or metal carbonate nanoparticles.

  Zero-valent nanoparticles can be obtained by reducing the soluble metal salt using an inorganic reducing agent such as tetrahydroborate, dimethylamine borane, hydrazine, or phosphinate, or an organic reducing agent such as an amine or diol compound. Can be obtained.

  As an example of the gas phase method, a raw material solid is put in a crucible, heated by a high frequency induction heating method to generate metal vapor, and rapidly cooled by collision with gas molecules such as He, Ar, etc., and vaporized in gas. Alternatively, metal oxide nanoparticles can be obtained using a microwave plasma CVD method. It can also be synthesized by spray pyrolysis. The yield of the reaction can be confirmed by chemical analysis such as ICP, and the composition ratio of each particle can be confirmed by high-resolution TEM such as FE-TEM. The crystals of the nanoparticles can be confirmed by X-ray diffraction (XD) or electron diffraction (ED).

  Nanoparticles synthesized by the vapor phase method or spray pyrolysis method can be dispersed in an appropriate dispersion medium to obtain a nanoparticle-containing dispersion. Nanoparticles synthesized by the liquid phase method are already in a nanoparticle-containing dispersion, so they can be used as they are, or concentrated, purified, to remove unreacted products and by-products, and adjust the concentration. Various treatments such as dilution and desalting may be performed. Examples of the dispersion medium include water, alcohols, glycols and the like. Among alcohols, ethanol, methanol, isopropanol, butanol, and n-hexane are preferable, and a mixed solution with water is also used.

The nanoparticle-containing dispersion preferably contains an organic compound such as an adsorptive compound (dispersant) or a surfactant. The adsorptive compound and the surfactant are adsorbed on the surface of the nanoparticles in the liquid and contribute to improving the stability of the nanoparticle-containing dispersion by modifying the surface of the nanoparticles. The nanoparticles can be hydrophilic or hydrophobic. As the adsorptive compound, a compound containing —SH, —CN, —NH 2, —SO ₂ OH, —SOOH, —OPO (OH) ₂ , —COOH, or the like is effective, and among these, —SH or — COOH-containing compounds are preferred. In the case of a hydrophilic colloid, it is preferable to use an adsorptive compound having a hydrophilic group (for example, —SO ₃ M or —COOM (M represents a hydrogen atom, an alkali metal atom or an ammonium molecule)). In addition, anionic surfactants (for example, bis (2-ethylhexyl) sulfosuccinic acid and sodium dodecylbenzenesulfonate), nonionic surfactants (for example, polyalkyl glycol alkyl esters and alkylphenyl ethers), fluorine-based surfactants It is also preferable to contain a surfactant and a hydrophilic polymer (for example, hydroxyethyl cellulose, polyvinyl pyrrolidone, polyvinyl alcohol, polyethylene glycol, gelatin, etc.) in the nanoparticle-containing dispersion.

"Base material"
The base material applicable to the thin film formation method of this invention is demonstrated.

  The substrate used in the present invention is particularly limited as long as a thin film such as a plate-like, sheet-like or film-like planar shape or a three-dimensional shape such as a lens or other molded product can be formed on the surface thereof. There is no. There is no limitation on the form or material of the substrate as long as the substrate is exposed to a mixed gas in a plasma state regardless of whether it is in a stationary state or in a transferred state, and a uniform thin film is formed. The shape may be a planar shape or a three-dimensional shape, and examples of the planar shape include a glass plate and a resin film. Various materials such as glass, resin, earthenware, metal, and non-metal can be used. Specifically, examples of the glass include a glass plate and a lens, and examples of the resin include a resin lens, a resin film, a resin sheet, and a resin plate. In the present invention, it is preferable to use a resin film.

  Since the resin film can form a transparent conductive film by continuously transferring between or in the vicinity of the electrodes of the atmospheric pressure plasma processing apparatus according to the present invention, it is not a batch type like a vacuum system such as sputtering. Suitable for mass production, suitable as a continuous and highly productive production method.

  The material of the molded product such as resin film, resin sheet, resin lens, resin molded product is cellulose ester such as cellulose triacetate, cellulose diacetate, cellulose acetate propionate or cellulose acetate butyrate, polyethylene terephthalate or polyethylene naphthalate. Polyester, Polyolefin such as polyethylene and polypropylene, Polyvinylidene chloride, Polyvinyl chloride, Polyvinyl alcohol, Ethylene vinyl alcohol copolymer, Syndiotactic polystyrene, Polycarbonate, Norbornene resin, Polymethylpentene, Polyetherketone, Polyimide, Polyether Sulfone, polysulfone, polyetherimide, polyamide, fluororesin, polymethylacrylate , Mention may be made of acrylate copolymers and the like.

  These materials can be used alone or in combination as appropriate. Above all, ZEONEX and ZEONOR (manufactured by ZEON CORPORATION), amorphous cyclopolyolefin resin film ARTON (manufactured by JSR Corporation), polycarbonate film Pure Ace (manufactured by Teijin Limited), Konicatac of cellulose triacetate film Commercially available products such as KC4UX and KC8UX (manufactured by Konica Minolta Opto Co., Ltd.) can be preferably used. Furthermore, even for materials with a large intrinsic birefringence such as polycarbonate, polyarylate, polysulfone and polyethersulfone, conditions such as solution casting film formation, melt extrusion film formation, and further stretching conditions in the vertical and horizontal directions What can be used can be obtained by setting etc. suitably.

  Among these, a cellulose ester film that is optically isotropic is preferably used for the optical element. As the cellulose ester film, a cellulose triacetate film and cellulose acetate propionate are preferably used as described above. As the cellulose triacetate film, a commercially available product, Konica Katak KC4UX (manufactured by Konica Minolta Opto) or the like is useful.

  Those obtained by coating gelatin, polyvinyl alcohol, acrylic resin, polyester resin, cellulose ester resin or the like on the surface of these resins can also be used. Further, an antiglare layer, a clear hard coat layer, a barrier layer, an antifouling layer and the like may be provided on the thin film side of these resin films. Moreover, you may provide an adhesive layer, an alkali barrier coat layer, a gas barrier layer, a solvent resistant layer, etc. as needed.

  Moreover, the base material used for this invention is not limited to said description. The film thickness is preferably 10 to 1000 μm, more preferably 40 to 200 μm.

《Nanoparticle applying device and atmospheric pressure plasma processing device》
Next, the nanoparticle application | coating apparatus and atmospheric pressure plasma processing apparatus which are used for the thin film formation method of this invention are demonstrated using FIGS. The embodiment of the present invention is not limited to these.

  FIG. 1 is a schematic view of an ultrasonic sprayer used when a dispersion containing nanoparticles containing a metal atom-containing compound is applied on a substrate or supplied between electrodes. Thereby, a nanoparticle can be supplied on a base material and between electrodes.

  In FIG. 1, 1 is an ultrasonic atomizer, 11 is an introduction tube for introducing nitrogen gas, 12 is a raw material reservoir for storing a dispersion L of nanoparticles containing a metal atom-containing compound, and 13 is an ultrasonic wave. A generation unit 14 is a power source connected to the ultrasonic generation unit 13, and 15 is a discharge tube that discharges the generated droplets. When nitrogen gas is introduced from the introduction pipe 11 into the raw material storage unit 12 and the power source 14 is turned on to generate ultrasonic waves from the ultrasonic wave generation unit 13, droplets are generated. The droplets generated in this way are discharged out of the ultrasonic sprayer 1 through the discharge tube 15, and the droplets are sprayed at an appropriate place in an atmospheric pressure plasma apparatus (not shown). The atomizer is not limited to the ultrasonic atomizer, and is selected according to the type of film to be formed and the nature of the atomizing liquid, such as an atomizer that atomizes using gas or an atomizer that atomizes the liquid by applying pressure to the atomizing liquid. The

  FIG. 2 is a schematic view of a single-wafer atmospheric pressure plasma processing apparatus equipped with an ultrasonic atomizer. In FIG. 2, 1 is a sprayer similar to FIG. The droplets M sprayed downward from the ultrasonic sprayer 1 are applied onto the substrate S in the spray space A. There is no need to use one ultrasonic atomizer depending on the size of the base material and the area to be formed at a time, and a wide base material can be sprayed side by side according to the base material. Reference numeral 21 denotes a fixed first electrode, and reference numeral 22 denotes a second electrode that supports the substrate S and can repeatedly move in the direction of white arrows in the figure. The first electrode 21 and the second electrode 22 are provided to face each other with a predetermined gap, and this gap constitutes the discharge space D. The first electrode 21 and the second electrode 22 are connected to a filter 27A or 27B, which is a load, a matching box 26A or 26B, and a high-frequency power source 25A or 25B, respectively, and are grounded. The filter is inserted in order to superimpose two different types of high-frequency electric fields in the discharge space so that the high-frequency waves do not affect each other's power supply. The matching box is inserted to cancel the reactance component of the load and correct the impedance in order to effectively use the energy of the high-frequency power source.

The first high-frequency electric field generated by the high-frequency power supply 25A and the second high-frequency electric field generated by the high-frequency power supply 25B satisfy the following relationship. First than the frequency omega ₁ of the high frequency electric field of the second high-frequency electric field frequency omega ₂ is high and the strength V ₁ of the first high frequency electric field, strength V ₂ and the discharge start of the second high-frequency electric field The relationship with the electric field strength IV satisfies V ₁ ≧ IV> V ₂ or V ₁ > IV ≧ V ₂ . As described above, by superimposing two types of high-frequency electric fields satisfying this relationship, a stable and high-density discharge state can be achieved even when a gas such as nitrogen having a high discharge starting electric field strength is used. High-quality film formation can be performed.

  For example, a high frequency with a frequency of 100 kHz is used as the first high frequency electric field, and a high frequency with a frequency of 13.56 MHz is used as the second high frequency electric field facing the first high frequency electric field. Between the electrodes, a mixed gas of 0.1% by volume of oxygen gas and 1% by volume of hydrogen gas with respect to nitrogen gas is introduced to form a discharge space.

  The substrate S such as a resin film is placed on the second electrode 22 and repeatedly moves between the spray space A and the discharge space D. In the spray space A, dispersion droplets containing nanoparticles are applied onto the substrate S. In the discharge space D, a discharge gas such as nitrogen is supplied, two kinds of high-frequency electric fields are superimposed, and high-density plasma is generated, and the substrate S to which nanoparticles are applied is exposed. By repeating this, a thin film is formed.

  FIG. 3 is a schematic view of a roll-type atmospheric pressure plasma processing apparatus equipped with an ultrasonic atomizer. In FIG. 3, the same reference numerals as those in FIG. 2 are the same as the members described in FIG. In FIG. 3, S is a long base material such as a resin film. The base material S is wound around the roll electrode 22R that is the second electrode, and is conveyed in the direction of the arrow in the drawing. The droplet M of the dispersion containing nanoparticles sprayed from the ultrasonic sprayer 1 is applied on the substrate S in the spray space A. Thereafter, when the substrate S to which the droplet M is applied passes through the discharge space D formed between the first electrode 21 and the second electrode 22R, a thin film is formed.

  FIG. 4 is a schematic view of another type of atmospheric pressure plasma processing apparatus that can be used in the present invention. In FIG. 4, an atmospheric pressure plasma processing apparatus 30 is an apparatus having an electric field applying means 40 having two power sources, a gas / droplet supplying means 50, and an electrode temperature adjusting means 60.

  Dispersion containing nanoparticles supplied from the gas / droplet supply means 50 between the counter electrodes (discharge space) 32 of the roll electrode (first electrode) 35 and the plurality of rectangular tube electrodes (second electrodes) 36 A mixture MG of nitrogen, whose body is a microdroplet (droplet) and a discharge gas, is supplied and activated here to deposit on the substrate F to form a thin film.

A discharge space (between the counter electrodes) 32 between the roll rotating electrode (first electrode) 35 and the square tube electrode (second electrode) 36 is connected to the roll rotating electrode (first electrode) 35 from the first power source 41. frequency omega _1, electric field intensity V _1, the frequency omega ₂ of the second power source 42 to the first high-frequency electric field, also prismatic electrode (second electrode) 36 of the current I _1, the electric field intensity V _2, the current I ₂ The second high-frequency electric field is applied.

A first filter 43 is installed between the roll rotation electrode (first electrode) 35 and the first power supply 41, and the first filter 43 easily passes a current from the first power supply 41 to the first electrode. The current from the second power supply 42 is grounded so that the current from the second power supply 42 to the first power supply is difficult to pass. Further, a second filter 44 is installed between the square tube electrode (second electrode) 36 and the second power source 42, and the second filter 44 has a current flowing from the second power source 42 to the second electrode. It is designed to make it difficult to pass the current from the first power supply 41 to the second power supply by grounding the current from the first power supply 41.

In the present invention, the roll rotation electrode 35 may be the second electrode, and the rectangular tube electrode 36 may be the first electrode. In any case, the first power source is connected to the first electrode, and the second power source is connected to the second electrode. The first power supply preferably applies a higher frequency electric field strength (V ₁ > V ₂ ) than the second power supply. Further, the frequency has the ability to satisfy ω ₁ <ω ₂ .

The current is preferably I ₁ <I ₂ . The current I ₁ of the first high-frequency electric field is preferably 0.3 to 20 mA / cm ² , more preferably 1.0 to 20 mA / cm ² . The current I ₂ of the second high-frequency electric field is preferably 10 to 100 mA / cm ² , more preferably 20 to 100 mA / cm ² .

  In the gas / droplet supply means 50, the gas / droplet MG generated by the gas / droplet generator 51 is introduced into the atmospheric pressure plasma processing container 31 from the air supply port 52 while controlling the flow rate.

  The base material F is unwound from the original winding (not shown) and conveyed, or is conveyed from the previous process, and the air entrained by the base material by the nip roll 65 via the guide roll 64 is blocked. While being in contact with the roll rotation electrode 35, it is transferred between the roll tube electrode 36 and the square tube electrode 36, and an electric field is generated from both the roll rotation electrode (first electrode) 35 and the square tube electrode (second electrode) 36. Then, discharge plasma is generated between the counter electrodes (discharge space) 32. The base material F forms a thin film with a gas in a plasma state while being wound while being in contact with the roll rotating electrode 35. The base material F passes through the nip roll 66 and the guide roll 67 and is wound up by a winder (not shown) or transferred to the next process.

  The discharged process waste liquid droplet G ′ is discharged from the exhaust port 53.

  In order to heat or cool the roll rotating electrode (first electrode) 35 and the rectangular tube electrode (second electrode) 36 during the formation of the thin film, the medium whose temperature is adjusted by the electrode temperature adjusting means 60 is fed by the liquid feed pump P. It sends to both electrodes through the piping 61, and temperature is adjusted from the inside of an electrode. Reference numerals 68 and 69 denote partition plates that partition the atmospheric pressure plasma processing vessel 31 from the outside.

  Each square tube electrode 36 shown in FIG. 4 may be a cylindrical electrode, but the square tube electrode has an effect of widening the discharge range (discharge area) as compared with the cylindrical electrode, and thus is preferably used in the present invention. It is done.

  The distance between the opposing first electrode and second electrode is the shortest distance between the surface of the dielectric and the surface of the conductive metallic base material of the other electrode when a dielectric is provided on one of the electrodes. Say that. When a dielectric is provided on both electrodes, it means the shortest distance between the dielectric surfaces. The distance between the electrodes is determined in consideration of the thickness of the dielectric provided on the conductive metallic base material, the magnitude of the applied electric field strength, the purpose of using the plasma, etc. From the viewpoint of performing 0.15 mm, 0.1 to 20 mm is preferable, and 0.5 to 2 mm is particularly preferable.

  As the atmospheric pressure plasma processing container 31, a processing container made of Pyrex (registered trademark) glass or the like is preferably used, but it is also possible to use a metal as long as insulation from the electrode can be obtained. For example, polyimide resin or the like may be attached to the inner surface of an aluminum or stainless steel frame, and the metal frame may be thermally sprayed to obtain insulation.

As the first power supply (high frequency power supply) installed in the atmospheric pressure plasma processing apparatus,
Applied power symbol Manufacturer Frequency Product name A1 Shinko Electric 3kHz SPG3-4500
A2 Shinko Electric 5kHz SPG5-4500
A3 Kasuga Electric 15kHz AGI-023
A4 Shinko Electric 50kHz SPG50-4500
A5 HEIDEN Research Laboratories 100kHz * PHF-6k
A6 Pearl Industry 200kHz CF-2000-200k
A7 Pearl Industry 400kHz CF-2000-400k
And the like, and any of them can be used.

As the second power source (high frequency power source),
Applied power supply symbol Manufacturer Frequency Product name B1 Pearl Industry 800kHz CF-2000-800k
B2 Pearl Industry 2MHz CF-2000-2M
B3 Pearl Industry 13.56MHz CF-5000-13M
B4 Pearl Industry 27MHz CF-2000-27M
B5 Pearl Industry 150MHz CF-2000-150M
And the like, and any of them can be preferably used.

  Of the above power supplies, * indicates a HEIDEN Laboratory impulse high-frequency power supply (100 kHz in continuous mode). Other than that, it is a high-frequency power source that can apply only a continuous sine wave.

  In the present invention, it is preferable to employ an electrode capable of maintaining a uniform and stable discharge state by applying such an electric field in an atmospheric pressure plasma processing apparatus.

In the present invention, the electric power applied between the electrodes facing each other supplies power (power density) of 1 W / cm ² or more to the second electrode (second high-frequency electric field) to excite the discharge gas to generate plasma. Apply energy to the nanoparticles to form a thin film. The upper limit value of the power supplied to the second electrode is preferably 50 W / cm ² , more preferably 20 W / cm ² . The lower limit is preferably 1.2 W / cm ² . The discharge area (cm ² ) refers to an area in a range where discharge occurs in the electrode.

Further, by supplying power (output density) of 1 W / cm ² or more to the first electrode (first high frequency electric field), the output density is improved while maintaining the uniformity of the second high frequency electric field. be able to. Thereby, a further uniform high-density plasma can be generated, and a further improvement in film forming speed and an improvement in film quality can be achieved. Preferably it is 5 W / cm ² or more. The upper limit value of the power supplied to the first electrode is preferably 50 W / cm ² .

  Here, the waveform of the high-frequency electric field is not particularly limited. There are a continuous sine wave continuous oscillation mode called a continuous mode, an intermittent oscillation mode called ON / OFF intermittently called a pulse mode, and either of them may be adopted, but at least the second electrode side (second The high-frequency electric field is preferably a continuous sine wave because a denser and better quality film can be obtained.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these. Unless otherwise specified, “%” in the examples represents “mass%”.

<< Production of thin film >>
[Preparation of thin film 1]
(Synthesis of Sn / In composite nanoparticles)
2.00 g of indium (III) chloride and 4.05 g of L-tartaric acid were dissolved in 100 ml of deoxygenated water and sufficiently stirred to prepare solution A-1. Further, 5.3 g of potassium hydroxide was dissolved in 100 ml of deoxygenated water to prepare a solution B-1. Furthermore, C-1 solution was prepared by dissolving 2.88 g of sodium tetrahydroborate in 20 ml of deoxygenated water.

  In a room temperature argon box, the A-1 solution and the B-1 solution were placed in a 300 ml three-necked flask and mixed. At this time, the pH of the mixed solution was 8.5. After adding C-1 liquid which is a reducing agent to this mixed solution, when the three-necked flask was transferred to a thermostat and heated to 60 ° C., the reduction began and the solution changed from transparent to brown. The reaction was performed at 60 ° C. for 60 minutes, and then cooled to room temperature by natural cooling. Subsequently, centrifugation and washing with water were repeated until the electric conductivity reached 50 μS / cm or less. The precipitate was redispersed in 20 ml of 0.5% hydroxyethylcellulose aqueous solution to prepare a dispersion containing Sn / In composite nanoparticles. When observed by TEM, the average particle diameter of the nanoparticles was 4.5 nm.

(Application of metal nanoparticles to the substrate, formation of plasma)
Using the atmospheric pressure plasma processing apparatus shown in FIG. 3, a DC electric field of +1 kV was applied to the supply port, and the dispersion liquid containing the Sn / In composite nanoparticles was sprayed onto the substrate 7 (polyether sulfone film). In the atmospheric pressure plasma processing apparatus of FIG. 3, a high frequency power source with a frequency of 100 kHz is connected to the electrode 22R holding the base material S, a high frequency power source with a frequency of 13.56 MHz is connected to the rod-shaped electrode 21 facing the electrode 22R, and between the power source body and the electrode. Is connected to a matching box for impedance matching. In addition, a filter is installed between the matching box and the electrode so that no mutual current flows. A discharge gas was formed in the discharge space D by introducing a mixed gas of 0.1% by volume of oxygen gas and 1% by volume of hydrogen gas with respect to nitrogen gas. Since the portion exposed to the plasma gas is located downstream of the spray space A, the Sn / In composite nanoparticles are exposed to the plasma gas immediately after spraying.

The output density of the high-frequency power source with a frequency of 100 kHz was 3 W / cm ² and the output density of the high-frequency power source with 13.56 MHz was 5 W / cm ² .

This thin film forming method is a thin film forming method in which a dispersion containing nanoparticles is applied to the aforementioned base material, and the nanoparticles are subjected to atmospheric pressure plasma treatment. Note that the electrode that holds the base material S during film formation 22R was maintained at 150 ° C. and kept warm.

[Preparation of thin film 2]
In the production of the thin film 1, the generation of droplets is performed by replacing the ultrasonic atomizer shown in FIG. 1 with an atomizing device portion of a premax (a liquid phase droplet deposition device, LSMCD). A thin film 2 was prepared in the same manner except that the droplet outlet of the apparatus was connected to an outlet (not shown) to which the ultrasonic sprayer was connected.

  This thin film forming method is a thin film forming method in which a dispersion containing nanoparticles is applied on a substrate, and the nanoparticles are subjected to an atmospheric pressure plasma treatment.

[Preparation of thin film 3]
In the production of the thin film 1, the thin film 3 was produced in the same manner except that the atmospheric pressure plasma processing apparatus 30 shown in FIG. 4 was used instead of the atmospheric pressure plasma processing apparatus of FIG.

  A matching box for connecting a high frequency power source having a frequency of 100 kHz to the roll electrode 35 and connecting a high frequency power source having a frequency of 13.56 MHz to each cylindrical electrode 36 facing the roll electrode 35 and for impedance matching between the power source body and the electrode. Is connected. In addition, a filter is installed between the matching box and the electrode so that no mutual current flows. Then, a mixed gas of 0.1% by volume of oxygen gas and 1% by volume of hydrogen gas was introduced between the electrodes to form a discharge. In this processing apparatus, the nanoparticles 3 are subjected to atmospheric pressure plasma processing to become plasma gas 32, which is applied onto the substrate to form the thin film 3.

The output density of the 100 kHz high frequency power source was 3 W / cm ² and the output density of the 13.56 MHz high frequency power source was 5 W / cm ² .

  This thin film forming method is a thin film forming method in which a dispersion containing nanoparticles is subjected to atmospheric pressure plasma treatment, and nanoparticles subjected to atmospheric pressure plasma treatment are applied onto a substrate.

  Here again, the electrode 35 holding the substrate S during film formation was maintained at 150 ° C. and kept warm.

[Preparation of thin film 4]
In the production of the thin film 1, the method for applying the nanoparticles to the substrate was applied by spin coating instead of the spray method. In addition, Corning # 7059 glass substrate was used as the substrate, and as a pretreatment, the glass substrate was ultrasonically cleaned in a cleaning solution (Furuuchi Chemical Co., Ltd. Semico Clean 56) for 10 minutes and then washed several times with ion-exchanged water. Then, it was held for 10 minutes in boiling acetone, pulled up, and naturally dried. After the nanoparticles were applied to the substrate by spin coating, the coated surface was treated with a single wafer atmospheric pressure plasma apparatus shown in FIG. 2 before drying. Here, a droplet is not sprayed on the substrate, a mixed gas of 0.1% by volume of oxygen gas and 1% by volume of hydrogen gas is introduced between the electrodes, and a high-frequency power source with a frequency of 100 kHz is supplied to the stage electrode 22. Is connected to the cylindrical electrode 21 facing it, and a matching box for impedance matching is connected between the power source body and the electrode. In addition, a filter was installed between the matching box and the electrode to prevent mutual currents from flowing into each other, and an electric field was applied between the electrodes to form a discharge.

The output density of the 100 kHz high frequency power source was 3 W / cm ² and the output density of the 13.56 MHz high frequency power source was 5 W / cm ² .

  The thin film 4 was produced in a series of steps of coating → drying → atmospheric pressure plasma treatment with the above contents.

  This thin film forming method is a thin film forming method in which a dispersion containing nanoparticles is applied on a substrate, and the nanoparticles are subjected to an atmospheric pressure plasma treatment.

[Preparation of thin film 5]
In the production of the thin film 1, the prepared dispersion liquid containing Sn / In composite nanoparticles was discharged onto a substrate using an ink jet printer, and then irradiated with a laser to produce the thin film 5. The laser irradiation was performed in the atmosphere at a linear velocity of 5 m / s using a semiconductor laser device having an oscillation wavelength of 803 nm, an output of 6 mW, and a spot diameter of 10 μm.

[Preparation of thin film 6]
In the production of the thin film 1, the prepared dispersion containing Sn / In composite nanoparticles is placed on a pretreated glass substrate in the same manner as the method for forming the thin film 4, and is rotated at 500 to 2000 rpm. The coating was applied by spin coating for 20 seconds, followed by drying at 80 ° C. for 2 hours. The thin film after drying was baked at 500 ° C. for 30 minutes in an air atmosphere using an electric furnace, and then further baked at 500 ° C. for 30 minutes in an argon atmosphere to prepare the thin film 6.

<< Evaluation of thin film >>
The following evaluation was performed about each produced said thin film.

(Measurement of surface resistivity)
In accordance with JIS R 1637, the surface resistivity (Ω · cm) was determined by the four probe method. In addition, Mitsubishi Chemical Loresta-GP and MCP-T600 were used for the measurement.

(Measurement of transmittance)
According to JIS R 1635, transmittance (%) at a wavelength of 550 nm was measured using a spectrophotometer 1U-4000 type manufactured by Hitachi, Ltd.

(Measurement of surface roughness)
The centerline average surface roughness (nm) defined by JIS B 0601 was measured.

(Evaluation of adhesion)
A cross-cut test based on JIS K 5400 was performed. On the surface of the formed thin film, using a single-edged razor, eleven cuts were made vertically and horizontally at intervals of 1 mm at 90 degrees with respect to the surface to make 100 1 mm square grids. A commercially available cellophane tape is affixed on top of this, and one end of the tape is peeled off vertically by hand, and the ratio (%) of the area where the thin film has not been peeled off to the tape area affixed from the score line is measured and adhered. A measure of gender.

  Table 1 shows the measurement and evaluation results obtained as described above.

  As is clear from the results shown in Table 1, the thin film produced by the thin film forming method of the present invention has excellent surface resistance characteristics and high transmittance with respect to the comparative example, high surface uniformity, and It turns out that it is excellent in adhesiveness with a base material.

It is the schematic which shows an example of an ultrasonic atomizer. It is the schematic which shows an example of a single wafer type atmospheric pressure plasma processing apparatus. It is the schematic which shows an example of a roll-type atmospheric pressure plasma processing apparatus. It is the schematic which shows another example of a roll-type atmospheric pressure plasma processing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ultrasonic sprayer 11 Introducing pipe 12 Raw material storage part 13 Ultrasonic wave generation part 14 Power supply 15 Release pipe 21 1st electrode 22, 32 2nd electrode 22R, 35 Roll rotating electrode 23A, 23B Filter 25A, 25B High frequency power supply 24A, 24B Matching Box 30 Atmospheric pressure plasma processing apparatus 31 Atmospheric pressure plasma processing vessel 32, D Discharge space 36 Rectangular tube electrode 40 Electric field applying means 41 First power supply 42 Second power supply 43 First filter 44 Second filter 50 Gas / droplet supply means 51 Gas / Droplet Generator 52 Air Supply Port 53 Exhaust Port 60 Electrode Temperature Control Means 64, 67 Guide Roll 65, 66 Nip Roll 68, 69 Partition A A Spray Space M Gas / Droplet F, S Substrate G ′ Process Waste Droplet

Claims (15)

A method of forming a thin film by applying nanoparticles to a substrate and subjecting the nanoparticles applied on the substrate to an atmospheric pressure plasma treatment, wherein the atmospheric pressure plasma treatment is performed at atmospheric pressure or atmospheric pressure. Under a pressure close to atmospheric pressure, a gas is supplied between opposing electrodes, and a high-frequency electric field is generated between the electrodes to make the gas an excitation gas, and the nanoparticles applied on the substrate to the excitation gas A method for forming a thin film, characterized by being a treatment for exposure. The thin film forming method according to claim 1, wherein the gas contains nitrogen. The thin film forming method according to claim 1 or 2, wherein an average particle diameter of the nanoparticles is 1 nm or more and 20 nm or less. The said nanoparticle is a metal atom containing compound, The thin film formation method of any one of Claims 1-3 characterized by the above-mentioned. 5. The thin film forming method according to claim 4, wherein the metal atom of the metal atom-containing compound is at least one selected from the group consisting of In, Ga, Al, Sn, Ge, Sb, Bi, and Zn. . The thin film forming method according to claim 1, wherein the base material is a resin film. The thin film forming method according to claim 1, wherein an atmospheric pressure plasma treatment is performed by disposing the base material between electrodes. A method of forming a thin film by subjecting nanoparticles to atmospheric pressure plasma treatment and applying the atmospheric pressure plasma treated nanoparticles onto a substrate, wherein the atmospheric pressure plasma treatment is performed at or near atmospheric pressure. The gas is supplied between opposing electrodes under the pressure of the gas, and a high-frequency electric field is generated between the electrodes to make the gas an excitation gas, and the nanoparticle is exposed to the excitation gas. Thin film forming method. The method for forming a thin film according to claim 8, wherein the gas contains nitrogen. The thin film forming method according to claim 8 or 9, wherein an average particle size of the nanoparticles is 1 nm or more and 20 nm or less. The said nanoparticle is a metal atom containing compound, The thin film formation method of any one of Claims 8-10 characterized by the above-mentioned. 12. The method of forming a thin film according to claim 11, wherein the metal atom of the metal atom-containing compound is at least one selected from the group consisting of In, Ga, Al, Sn, Ge, Sb, Bi, and Zn. . The thin film forming method according to claim 8, wherein the base material is a resin film. The thin film forming method according to any one of claims 8 to 13, wherein an atmospheric pressure plasma treatment is performed by disposing the base material between electrodes. A thin film formed by the thin film forming method according to claim 1.

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