JP5026673B2 - Method for producing metal oxide film - Google Patents

Description

  The present invention relates to a method for producing a metal oxide film capable of obtaining a metal oxide film excellent in transparency, denseness, adhesion and the like.

  Conventionally, compound semiconductors, particularly metal oxide films, have been widely used as materials for photoelectric conversion elements and display elements. Many of these metal oxide films have been manufactured by sputtering, vapor deposition, CVD, ion plating, printing, etc., but these methods require expensive equipment or are separately fired. There was a problem such as being necessary. In order to solve such a problem, a method for producing a metal oxide film by a spray pyrolysis method that does not require a vacuum apparatus has been proposed.

  As a method for producing a metal oxide film by a spray pyrolysis method, for example, in Patent Document 1, a solution having a component of a metal compound is atomized by an ultrasonic vibrator to form droplets, and a carrier such as dry air A method is disclosed in which a metal compound film is formed by spraying on a film-forming substrate heated in advance together with a gas. However, since this method uses dry air to transport the atomized droplets and is performed at a higher temperature, the droplets are oxidized before reaching the base material to form metal oxide fine particles. In addition, there is a problem that it is difficult to produce a metal oxide film excellent in transparency, denseness, adhesion, and the like.

  Patent Document 2 discloses a method for obtaining a tin oxide film by spraying an organic solvent liquid of dibutyltin diacetate onto a heated glass substrate. However, also in this method, a carrier gas is used during spraying, and the same problem as described above has occurred.

JP 2004-259494 A JP-A-8-225830

  The present invention has been made in view of the above problems, and mainly provides a method for producing a metal oxide film capable of obtaining a metal oxide film having excellent transparency, denseness, adhesion, and the like. It is the purpose.

  In the present invention, the metal oxide film forming solution in which the metal salt or the metal complex is dissolved as a metal source is atomized by a spray device, and the atomized solution for forming the metal oxide film and the metal oxide film forming are formed. A method for producing a metal oxide film, wherein a metal oxide film is obtained on the substrate by contacting the substrate heated to a temperature equal to or higher than the temperature, wherein the spray device is used for forming the metal oxide film. Provided is a method for producing a metal oxide film, which is an apparatus that does not use air to atomize a solution.

  According to the present invention, since the spray device is a device that does not use air to atomize the metal oxide film forming solution, the atomized metal oxide film forming solution is It is possible to prevent the metal oxide fine particles from being oxidized before reaching the base material, and to obtain a metal oxide film excellent in transparency, denseness, adhesion and the like.

  Moreover, in the said invention, it is preferable that the said spray apparatus is an airless spray or a rotary atomization spray. This is because a metal oxide film having excellent transparency, denseness, adhesion, and the like can be obtained.

  In the present invention, a stage for holding the substrate, a heating device for heating the substrate, a spray device for atomizing a solution for forming a metal oxide film in which a metal salt or metal complex is dissolved as a metal source, and A metal oxide film forming solution supply device for supplying the metal oxide film forming solution to the spray device, wherein the spray device is the metal oxide film An apparatus for producing a metal oxide film, characterized in that it is an apparatus that does not use air to atomize a film-forming solution.

  According to the present invention, a metal oxide film excellent in transparency, denseness, adhesion, and the like can be obtained by using the spray device. Furthermore, a uniform and dense metal oxide film can be manufactured at low cost without requiring expensive equipment such as a vacuum apparatus and complicated processes.

  Moreover, in the said invention, it is preferable that the said spray apparatus is an airless spray or a rotary atomization spray. This is because a metal oxide film having excellent transparency, denseness, adhesion, and the like can be obtained.

  Moreover, in the said invention, it is preferable that a heating apparatus is a hot plate. This is because the substrate temperature can be stably maintained.

  In this invention, there exists an effect that the metal oxide film excellent in transparency, denseness, adhesiveness, etc. can be obtained by using a specific spray apparatus.

  Hereinafter, the metal oxide film manufacturing method and the metal oxide film manufacturing apparatus of the present invention will be described in detail.

A. Method for Producing Metal Oxide Film In the method for producing a metal oxide film of the present invention, the solution for forming a metal oxide film in which a metal salt or a metal complex is dissolved as a metal source is atomized and atomized by a spray device. A method for producing a metal oxide film in which a metal oxide film is obtained on a substrate by bringing the metal oxide film forming solution into contact with a substrate heated to a temperature equal to or higher than the metal oxide film formation temperature. The spray device is a device that does not use air to atomize the metal oxide film forming solution.

According to the present invention, since the spray device is a device that does not use air to atomize the metal oxide film forming solution, the atomized metal oxide film forming solution is It is possible to prevent the metal oxide fine particles from being oxidized before reaching the base material, and to obtain a metal oxide film excellent in transparency, denseness, adhesion and the like.
In particular, in the present invention, a highly transparent metal oxide film can be obtained. For example, when the metal oxide film obtained by the present invention is used as a transparent electrode of a solar cell member, a solar cell The performance of can be greatly improved. In addition, according to the present invention, a uniform and dense metal oxide film can be manufactured at low cost without requiring expensive equipment such as a vacuum apparatus or complicated processes.

  Next, the manufacturing method of the metal oxide film of this invention is demonstrated using drawing. FIG. 1 is a process diagram showing an example of a method for producing a metal oxide film of the present invention. In the method for producing a metal oxide film of the present invention, the atomized metal oxide film forming solution 2 in which a metal salt or a metal complex is dissolved as a metal source is atomized by the spray device 1 to form the atomized metal oxide film. This is a method for obtaining a metal oxide film 4 on the base material 3 by bringing the solution 2 into contact with the base material 3 heated to a temperature equal to or higher than the metal oxide film formation temperature (FIG. 1 (a)). FIG. 1 (b)).

  Next, the “metal oxide film forming temperature” used in the present invention will be described. In the present invention, the “metal oxide film formation temperature” refers to a temperature at which a metal element contained in a metal source combines with oxygen and can form a metal oxide film on a substrate, a metal salt, It differs greatly depending on the type of metal source such as a metal complex and the composition of a solution for forming a metal oxide film such as a solvent. In the present invention, such “metal oxide film formation temperature” can be measured by the following method. That is, the lowest base material on which a metal oxide film can be formed by preparing a solution for forming a metal oxide film that actually contains a desired metal source and changing the heating temperature of the base material to make contact Measure the heating temperature. This minimum substrate heating temperature can be set as the “metal oxide film forming temperature” in the present invention. At this time, whether or not the metal oxide film is formed is usually judged from the result obtained from an X-ray diffraction apparatus (Rigaku, RINT-1500). In the case of an amorphous film having no crystallinity, photoelectron spectroscopy is performed. It shall judge from the result obtained from the analyzer (the product made by VG Scientific, ESCALAB 200i-XL).

Next, the change in the valence of the metal source in the method for producing a metal oxide film of the present invention will be described. The change in the valence of the metal source will be described using, for example, a case where a cerium oxide (CeO ₂ ) film is obtained from a metal oxide film forming solution containing cerium ions Ce ³⁺ as a metal source. FIG. 2 is a Pourbaix diagram of cerium. In the present invention, cerium existing as Ce ³⁺ (corresponding to the Ce ³⁺ region in the figure) in the metal oxide film forming solution is a heated substrate. By contacting with the material, the valence is changed to become a CeO ₂ film (corresponding to the CeO ₂ region in the figure). That is, it can be considered that the substrate has moved from the Ce ³⁺ region to the CeO ₂ region by applying thermal energy to the substrate.

The metal oxide film-forming solution contains at least a metal source and a solvent. In the present invention, the metal oxide film-forming solution contains an oxidizing agent, a reducing agent, and the like. It is preferable. This is because the metal oxide film can be formed even at a lower substrate heating temperature. Regarding the mechanism in this case, cerium nitrate (Ce (NO ₃ ) ₃ ) as a metal source, borane-dimethylamine complex (also known as dimethylamine borane, DMAB) as a reducing agent, water as a solvent, cerium oxide (CeO ₂ ) Description will be made using the case of forming a film.

The cerium oxide film is not yet clear, but is considered to be formed by the following six equations.
(I) Ce (NO ₃ ) ₃ → Ce ³⁺ + 3NO ₃ ⁻
(Ii) (CH ₃ ) ₂ NHBH ₃ + 2H ₂ O → BO ₂ ⁻ + (CH ₃ ) ₂ NH + 7H ⁺ + 6e ⁻
(Iii) 2H ₂ O + 2e ⁻ → 2OH ⁻ + H ₂
(Iv) Ce ³⁺ → Ce ⁴⁺ + e ⁻
(V) Ce ⁴⁺ + 2OH ⁻ → Ce (OH) ₂ ²⁺
(Vi) Ce (OH) ₂ ²⁺ → CeO ₂ + H ₂

At this time, cerium nitrate becomes cerium ions in the aqueous solution (formula (i)), and then the reducing agent DMAB is decomposed by heating (formula (ii)), thereby releasing electrons. Thereafter, the emitted electrons induce water electrolysis (formula (iii)) to generate hydroxide ions and raise the pH of the metal oxide film forming solution. As a result, the cerium ion changes the valence (formula (iv)) and further reacts with the generated hydroxide ion (formula (v)) to produce Ce (OH) ₂ ²⁺ . Thereafter, Ce (OH) ₂ ^{2+ in the} vicinity of the base material becomes CeO _{2 as the} pH increases (formula (vi)). That is, by adding the reducing agent, the pH of the metal oxide film forming solution is increased, and an environment in which a metal oxide film (CeO ₂ ) is likely to be generated is obtained, and a metal oxide film can be obtained at a lower heating temperature. It is thought that you can. Even when alcohol, an organic solvent, or the like is used as a solvent instead of water, a metal oxide film is obtained at a lower heating temperature due to a reaction similar to the above reaction or a small amount of water contained in the solvent. It is considered possible.
Hereafter, the manufacturing method of the metal oxide film of this invention is demonstrated in detail for every structure.

1. Spray Device First, the spray device used in the present invention will be described. The spray apparatus used in the present invention is an apparatus that does not use air to atomize the metal oxide film forming solution. In the present invention, the “method not using air to atomize the metal oxide film forming solution” refers to a method in which the metal oxide film forming solution is atomized using means other than air. In such a spray apparatus, air is not normally discharged from the nozzle.

  In addition, the normal air spray employs a method of atomizing the metal oxide film forming solution by colliding the metal oxide film forming solution and the air flow. It does not fall under “method that does not use air to atomize the solution”.

  In addition, the nozzle diameter of the spray device used in the present invention is not particularly limited as long as a desired metal oxide film can be obtained. Specifically, the nozzle diameter is within a range of 10 to 1000 μm, particularly 50 to 50 μm. It is preferable to be in the range of 500 μm, particularly in the range of 100 to 300 μm.

  In addition, the discharge amount for discharging the metal oxide film forming solution described later by the spray device used in the present invention is not particularly limited as long as a desired metal oxide film can be obtained. Is preferably in the range of 0.001 to 1 liter / min, more preferably in the range of 0.001 to 0.05 liter / min, and particularly preferably in the range of 0.01 to 0.05 liter / min.

  The spray device used in the present invention is not particularly limited as long as it is a device that does not use air in order to atomize the metal oxide film forming solution. Specifically, an airless spray, Examples thereof include a rotary atomizing spray.

The airless spray supplies the raw material solution to the vicinity of the inside of the discharge port having a special shape,
It is a spray that atomizes by being extruded with the pressure of a gas such as air. At this time, a gas such as air is used to extrude the raw material solution, and is different from an air spray that atomizes the air flow by directly colliding with the raw material solution.

  As such an airless spray, a commercially available airless spray can be used, and is not particularly limited, and examples thereof include those described in JP-A-8-24716. Specifically, A7A airless auto gun (manufactured by Nordson) AG4 airless auto gun (manufactured by Asahi Sunac Co., Ltd.) and the like can be mentioned.

  Moreover, the said rotary atomization spray is a spray of the system which atomizes a raw material solution with the energy of rotation. As such a rotary atomizing spray, a commercially available rotary atomizing spray can be used, and is not particularly limited. Can be mentioned. Specifically, RA-20 rotary atomizer (manufactured by Nordson), PCS0806 (manufactured by Asahi Sunac Co., Ltd.) and the like can be mentioned.

2. Next, the metal oxide film forming solution used in the method for producing a metal oxide film of the present invention will be described. The metal oxide film forming solution used in the present invention contains at least a metal source and a solvent described later. In the present invention, it is particularly preferable that the metal oxide film forming solution contains an oxidizing agent and / or a reducing agent. By adding an oxidizing agent and a reducing agent, a metal oxide film can be formed at a lower temperature, and since the temperature is lower, the atomized metal oxide film forming solution reaches the substrate. This is because it can be prevented from being oxidized to become metal oxide fine particles before forming, and a metal oxide film having high transparency can be formed.

(1) Metal source The metal source used for this invention comprises the metal oxide film formed on a base material. The metal source used in the present invention may be a metal salt or a metal complex as long as it dissolves in a solvent described later. The “metal complex” in the present invention includes a metal ion coordinated with an inorganic substance or an organic substance, or a so-called organometallic compound having a metal-carbon bond in the molecule.

  The concentration of the metal source in the metal oxide film-forming solution is usually 0.001 to 10 mol / l, preferably 0.01 to 1 mol / l when the metal source is a metal salt, When the metal source is a metal complex, it is usually 0.001 to 10 mol / l, and preferably 0.01 to 1 mol / l. When the concentration is below the above range, it takes time to form the metal oxide film, which may not be industrially suitable. When the concentration is above the above range, a metal oxide film having a uniform thickness is obtained. This is because it may not be possible.

  The metal element constituting such a metal source is not particularly limited as long as a desired metal oxide film can be obtained. For example, Mg, Al, Si, Ti, V, Mn, Fe, and Co Ni, Cu, Zn, Y, Zr, Ag, In, Sn, Ce, Sm, Pb, La, Hf, Sc, Gd, and Ta are preferably selected.

  Specific examples of the metal salt include chlorides, nitrates, sulfates, perchlorates, acetates, phosphates, bromates and the like containing the metal elements. Among these, in the present invention, it is preferable to use chloride, nitrate, and acetate. This is because these compounds are easily available as general-purpose products.

Specific examples of the metal complex include magnesium diethoxide, aluminum acetylacetonate, calcium acetylacetonate dihydrate, calcium di (methoxyethoxide), calcium gluconate monohydrate, citric acid Calcium tetrahydrate, calcium salicylate dihydrate, titanium lactate, titanium acetylacetonate, tetraisopropyl titanate, tetranormal butyl titanate, tetra (2-ethylhexyl) titanate, butyl titanate dimer, titanium bis (ethylhexoxy) bis (2 -Ethyl-3-hydroxyhexoxide), diisopropoxytitanium bis (triethanolaminate), dihydroxybis (ammonium lactate) titanium, diisopropoxytitanium bis (ethylacetate) Toacetate), titanium peroxo ammonium citrate tetrahydrate, dicyclopentadienyl iron (II), iron lactate (II) trihydrate, iron (III) acetylacetonate, cobalt (II) acetylacetonate , Nickel (II) acetylacetonate dihydrate, copper (II) acetylacetonate, copper (II) dipivaloylmethanate, copper (II) ethylacetoacetate, zinc acetylacetonate, zinc lactate trihydrate , Zinc salicylate trihydrate, zinc stearate, strontium dipivaloylmethanate, yttrium dipivaloylmethanate, zirconium tetra-n-butoxide, zirconium (IV) ethoxide, zirconium normal propyrate, zirconium normal butyrate , Zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zir Nitroacetylacetonate bisethylacetoacetate, zirconium acetate, zirconium monostearate, penta-n-butoxyniobium, pentaethoxyniobium, pentaisopropoxyniobium, tris (acetylacetonato) indium (III), indium 2-ethylhexanoate (III), tetraethyltin, dibutyltin oxide (IV), tricyclohexyltin (IV) hydroxide, lanthanum acetylacetonate dihydrate, tri (methoxyethoxy) lanthanum, pentaisopropoxytantalum, pentaethoxytantalum, tantalum ( V) Ethoxide, cerium (III) acetylacetonate n-hydrate, lead (II) citrate trihydrate, lead cyclohexanebutyrate and the like. Among them, in the present invention, magnesium diethoxide, aluminum acetylacetonate, calcium acetylacetonate dihydrate, titanium lactate, titanium acetylacetonate, tetraisopropyl titanate, tetranormal butyl titanate, tetra (2-ethylhexyl) titanate , Butyl titanate dimer, diisopropoxy titanium bis (ethylacetoacetate), iron (II) lactate trihydrate, iron (III) acetylacetonate, zinc acetylacetonate, zinc lactate trihydrate, strontium dipivaloyl Methanate, pentaethoxyniobium, tris (acetylacetonato) indium (III), indium (III) 2-ethylhexanoate, tetraethyltin, dibutyltin oxide (IV), lanthanum acetylacetonate dihydrate , It is preferable to use tri (methoxyethoxy) lanthanum, cerium (III) acetylacetonate n-hydrate.
In the present invention, the metal oxide film forming solution may contain two or more kinds of the above metal elements. By using a plurality of kinds of metal elements, for example, ITO, Gd—CeO ₂ , Sm A composite metal oxide film such as —CeO ₂ or Ni—Fe ₂ O ₃ can be obtained.

(2) Oxidizing agent The oxidizing agent used in the present invention has a function of accelerating oxidation of metal ions or the like formed by dissolving the above-described metal source. By changing the valence of metal ions or the like, an environment in which metal oxides are likely to be generated can be obtained, and a metal oxide film can be obtained at a lower substrate heating temperature compared to conventional methods.

  The concentration of the oxidizing agent in the metal oxide film-forming solution is usually 0.001 to 1 mol / l, particularly 0.01 to 0.1 mol / l, although it varies depending on the type of oxidizing agent. It is preferable that If the concentration is below the above range, the effect of lowering the substrate heating temperature may not be sufficiently exhibited. If the concentration is above the above range, there will be no significant difference in the obtained effect, and the cost This is because it is not preferable.

  Such an oxidizing agent is not particularly limited as long as it can be dissolved in a solvent described later and promote the oxidation of metal ions and the like. For example, hydrogen peroxide, sodium nitrite, Examples thereof include potassium nitrate, sodium bromate, potassium bromate, silver oxide, dichromic acid, and potassium permanganate. Among them, hydrogen peroxide and sodium nitrite are preferably used.

(3) Reducing agent The reducing agent used in the present invention has a function of releasing electrons by a decomposition reaction, generating hydroxide ions by water electrolysis, and raising the pH of the metal oxide film forming solution. It is. By increasing the pH of the metal oxide film forming solution, it can be led to a metal oxide region or a metal hydroxide region in the Pourbaix diagram, and an environment in which a metal oxide film is easily generated can be obtained. Compared with the method, a metal oxide film can be obtained at a lower substrate heating temperature.

  The concentration of the reducing agent in the metal oxide film forming solution varies depending on the type of the reducing agent, but is usually 0.001 to 1 mol / l, particularly 0.01 to 0.1 mol / l. It is preferable that If the concentration is below the above range, the effect of lowering the substrate heating temperature may not be sufficiently exhibited. If the concentration is above the above range, there will be no significant difference in the obtained effect, and the cost This is because it is not preferable.

  Such a reducing agent is not particularly limited as long as it can be dissolved in a solvent described later and can release electrons by a decomposition reaction. For example, borane-tert-butylamine complex, borane- Examples thereof include borane complexes such as N, N diethylaniline complex, borane-dimethylamine complex, borane-trimethylamine complex, sodium cyanoborohydride, and sodium borohydride. Among these, borane complex is preferably used.

  Moreover, in this invention, even if it uses combining a reducing agent and the oxidizing agent mentioned above, a metal oxide film can be obtained with a lower base-material heating temperature compared with the conventional method. Such a combination of a reducing agent and an oxidizing agent is not particularly limited as long as it is a combination capable of lowering the substrate heating temperature. For example, hydrogen peroxide or sodium nitrite and any reducing agent can be used. And a combination of an arbitrary oxidizing agent and a borane complex. Among them, a combination of hydrogen peroxide and a borane complex is preferable.

(4) Solvent The solvent used in the present invention is not particularly limited as long as it can dissolve the reducing agent and the metal source described above. For example, when the metal source is a metal salt, Examples thereof include water, methanol, ethanol, isopropyl alcohol, propanol, butanol and the like, lower alcohols having a total carbon number of 5 or less, toluene, and mixed solvents thereof. When the metal source is a metal complex, water, the above-mentioned And lower alcohols, toluene, and mixed solvents thereof. In the present invention, the above solvents may be used in combination. For example, a metal complex having low solubility in water but high solubility in an organic solvent, and low solubility in an organic solvent. In the case of using a reducing agent having high solubility in water, water and an organic solvent are mixed to dissolve both of them, and a uniform metal oxide film forming solution can be obtained.

(5) Additive The metal oxide film forming solution used in the present invention may contain additives such as ceramic fine particles, an auxiliary ion source, and a surfactant.

  When the ceramic fine particles are contained in the metal oxide film forming solution, a metal oxide film is formed so as to surround the ceramic fine particles, thereby obtaining a mixed film of different ceramics or increasing the volume of the metal oxide film. Can be achieved. Moreover, it is preferable that the content of the ceramic fine particles is appropriately selected according to the characteristics of the member to be used.

  Such ceramic fine particles are not particularly limited as long as the above object can be achieved. For example, ITO, aluminum oxide, zirconium oxide, silicon oxide, titanium oxide, tin oxide , Cerium oxide, calcium oxide, manganese oxide, magnesium oxide, barium titanate and the like.

  The auxiliary ion source generates hydroxide ions by reacting with electrons generated by thermal decomposition of the reducing agent, etc., and raises the pH of the metal oxide film forming solution. It leads to a physical region or a metal hydroxide region and becomes an environment where a metal oxide film is likely to be generated, and a metal oxide film can be obtained at a lower substrate heating temperature compared to conventional methods. The amount of the auxiliary ion source used is preferably appropriately selected according to the metal source and the reducing agent to be used.

Specific examples of such auxiliary ion sources include chlorate ions, perchlorate ions, chlorite ions, hypochlorite ions, bromate ions, hypobromate ions, nitrate ions, and nitrite ions. An ionic species selected from the group consisting of These auxiliary ion sources are believed to cause the following reactions in solution.
^{_{ClO 4 - + H 2 O +}} 2e - ⇔ ClO 3 - + 2OH -
^{_{ClO 3 - + H 2 O +}} 2e - ⇔ ClO 2 - + 2OH -
^{_{ClO 2 - + H 2 O +}} 2e - ⇔ ClO - + 2OH -
_{^{2ClO - + 2H 2 O + 2e}} - ⇔ Cl 2 (g) + 4OH -
^{_{BrO 3 - + 2H 2 O +}} 4e - ⇔ BrO - + 4OH -
_{^{2BrO - + 2H 2 O + 2e}} - ⇔ Br 2 + 4OH -
^{_{NO 3 - + H 2 O +}} 2e - ⇔ NO 2 - + 2OH -
NO ₂ ⁻ + 3H ₂ O + 3e ⁻ ＮＨ NH ₃ + 3OH ⁻

  The surfactant acts on the interface between the metal oxide film forming solution and the substrate surface, and can improve the contact area between the metal oxide film forming solution and the substrate surface. And a uniform metal oxide film can be obtained. The amount of the surfactant used is preferably selected and used according to the metal source and the reducing agent to be used.

  Such surfactants are specifically Surfinol 485, Surfinol SE, Surfinol SE-F, Surfinol 504, Surfinol GA, Surfinol 104A, Surfinol 104BC, Surfinol 104PPM, Surfinol 104E, Surfynol series such as Surfinol 104PA (all manufactured by Nissin Chemical Industry Co., Ltd.), NIKKOL AM301, NIKKOL AM313ON (all manufactured by Nikko Chemical Co., Ltd.) and the like can be mentioned.

3. Next, the base material used in the method for producing a metal oxide film of the present invention will be described. The material of the base material used in the present invention is not particularly limited as long as it has heat resistance against the above heating temperature. For example, glass, SUS, metal plate, ceramic substrate, heat resistant plastic, etc. Among them, glass, SUS, a metal plate, and a ceramic substrate are preferably used. This is because it is versatile and has sufficient heat resistance.

  The substrate used in the present invention is not particularly limited. For example, a substrate having a smooth surface, a microstructure, a hole, or a groove is engraved. It may be porous or provided with a porous film. Of these, those having a smooth surface, those having a fine structure, those having grooves, those which are porous, and those having a porous film are preferably used.

4). Contact Method Next, a contact method between the metal oxide film forming solution atomized by the spray device and the substrate heated to a temperature equal to or higher than the metal oxide film forming temperature will be described.

  The contact method in the present invention is not particularly limited as long as it is a method of bringing the atomized metal oxide film forming solution into contact with the heated base material. , A method of spraying the atomized metal oxide film forming solution onto the substrate, a method of passing the substrate through the mist-like space of the atomized metal oxide film forming solution, etc. .

  In the method of spraying the atomized metal oxide film forming solution onto the substrate, the diameter of the droplets of the atomized metal oxide film forming solution is not particularly limited. Specifically, it is preferably 0.1 to 1000 μm, and more preferably 0.5 to 300 μm. This is because when the droplet diameter is within the above range, the substrate temperature does not decrease when the droplet contacts the substrate, and a uniform metal oxide film can be obtained.

  Further, in the method of spraying the atomized metal oxide film forming solution onto the substrate, the discharge amount of the atomized metal oxide film forming solution is not particularly limited. Specifically, it is preferably within a range of 0.001 to 1 liter / min, more preferably within a range of 0.001 to 0.05 liter / min, and particularly preferably within a range of 0.01 to 0.05 liter / min. . If the above range is exceeded, the substrate temperature may be lowered, and if it is less than the above range, it takes time to form the metal oxide film, which is not preferable in terms of cost.

  The method for spraying the atomized metal oxide film forming solution onto the substrate is not particularly limited as long as it is a method capable of forming a desired metal oxide film. Examples thereof include a method of spraying on a coated substrate, a method of spraying on a moving substrate, and the like.

  As a method of spraying on the fixed base material, for example, as shown in FIG. 3, the fixed base material 3 is heated to a temperature equal to or higher than the metal oxide film formation temperature, The method of spraying the metal oxide film formation solution 2 atomized using the spray apparatus 1 etc. are mentioned. On the other hand, as a method of spraying on the moving base material, for example, as shown in FIG. 4, the base material 3 is continuously used with rollers 5 to 7 heated to a temperature equal to or higher than the metal oxide film forming temperature. The method of spraying the metal oxide film formation solution 2 atomized using the spray apparatus 3 with respect to this base material 3 etc. is mentioned. This method has an advantage that a metal oxide film can be continuously formed.

  Moreover, in the method of spraying the atomized metal oxide film forming solution onto the substrate, the shape of the substrate used is not particularly limited as long as it can be sprayed by a spray device. For example, a plate-like or cylindrical substrate can be used. When the cylindrical base material is used, a metal oxide film can be formed on the inner surface of the cylinder if the spray device can enter the cylinder.

  On the other hand, in the method of allowing the substrate to pass through a space in which the atomized metal oxide film forming solution is made into a mist, the diameter of the droplets of the atomized metal oxide film forming solution is: Although not particularly limited, specifically, it is preferably 0.1 to 300 μm, and more preferably 1 to 100 μm. This is because if the droplet diameter is within the above range, the substrate temperature can be prevented from decreasing, and a uniform metal oxide film can be obtained.

  The method for allowing the substrate to pass through the mist-like space of the atomized metal oxide film forming solution is not particularly limited. For example, as shown in FIG. And the like. The substrate 3 heated to a temperature equal to or higher than the metal oxide film forming temperature can be passed through the space in which the metal oxide film forming solution 2 is made into a mist using 1.

  In the present invention, the metal oxide film forming solution and the heated base material are brought into contact with each other. At that time, the base material is heated to a temperature equal to or higher than the above-mentioned “metal oxide film forming temperature”. Is done. Such “metal oxide film formation temperature” varies depending on the type of metal source such as metal salt and metal complex, and the composition of the metal oxide film formation solution such as a solvent. When an oxidizing agent and / or a reducing agent is not added to the catalyst, the temperature can usually be in the range of 400 to 600 ° C, and it is preferably in the range of 450 to 550 ° C. On the other hand, when an oxidizing agent and / or a reducing agent is added to the metal oxide film forming solution, it can usually be in the range of 150 to 400 ° C, and preferably in the range of 300 to 400 ° C. In particular, in the present invention, when an ITO film is formed on a substrate, it is preferably in the range of 300 to 500 ° C., more preferably in the range of 350 to 450 ° C. Moreover, when forming an alumina on a base material, it is preferable to exist in the range of 400-600 degreeC, especially within the range of 450-550 degreeC. In addition, when gadolinium-doped ceria is formed on the substrate, it is preferably in the range of 300 to 600 ° C, and more preferably in the range of 350 to 500 ° C.

  In the present invention, the method for heating the substrate is not particularly limited as long as the substrate can be heated to a desired temperature. For example, the atomized metal oxide film is formed. A method of heating the base material while bringing the solution into contact with the base material, or a method of heating the base material in advance before bringing the atomized metal oxide film forming solution into contact with the base material, etc. In the present invention, the former method is particularly preferable. This is because the substrate temperature can be stably maintained. As the former heating method, for example, a method using a hot plate, an infrared lamp or the like can be mentioned, and among them, a method using a hot plate is preferable. Further, the shape of the hot plate can be arbitrarily selected according to the shape of the base material, and specific examples thereof include a flat plate type and a cylindrical type. As a method for producing the metal oxide film using the hot plate, specifically, the base material was placed on the hot plate and heated, and when heated to a desired temperature, the base material was atomized. Examples thereof include a method of bringing a metal oxide film into contact with a solution for forming a metal oxide film and subsequently forming the metal oxide film while heating the substrate.

  Examples of the latter heating method include a method using a hot air blower, an oven, a baking furnace, and the like. For example, as a method for producing a metal oxide film using the hot air blower, specifically, the base material is heated by the hot air blower, and the hot air blower is stopped when heated to a desired temperature. Examples include a method of forming a metal oxide film by bringing a heated base material into contact with an atomized metal oxide film forming solution.

5. In addition, in the method for producing a metal oxide film of the present invention, the metal oxide film obtained by the above-described contact method or the like may be washed. The cleaning of the metal oxide film is performed to remove impurities present on the surface of the metal oxide film, for example, a method of cleaning using a solvent used in the metal oxide film forming solution. Etc.

B. Metal Oxide Film Manufacturing Apparatus Next, the metal oxide film manufacturing apparatus of the present invention will be described. The apparatus for producing a metal oxide film of the present invention includes a stage for holding a substrate, a heating device for heating the substrate, and a metal oxide film forming solution in which a metal salt or a metal complex is dissolved as a metal source. An apparatus for producing a metal oxide film, comprising: a spraying device that converts the metal oxide film forming solution to the spraying device, wherein the spraying device comprises: The apparatus is a system that does not use air in order to atomize the metal oxide film forming solution.

  According to the present invention, a metal oxide film excellent in transparency, denseness, adhesion, and the like can be obtained by using the spray device. Furthermore, a uniform and dense metal oxide film can be manufactured at low cost without requiring expensive equipment such as a vacuum apparatus and complicated processes.

  As a metal oxide film manufacturing apparatus of the present invention, for example, as shown in FIG. 6, a stage 12 that holds a base material 11, a heating device 13 that heats the base material 11, and a metal salt or metal as a metal source. A spray device 15 for atomizing the metal oxide film forming solution 14 in which the complex is dissolved; a metal oxide film forming solution supply device 16 for supplying the metal oxide film forming solution 14 to the spray device 15; An apparatus for producing a metal oxide film comprising: In the present invention, the spray device 15 is a device that does not use air in order to atomize the metal oxide film forming solution. In the present invention, in order to spray the metal oxide film forming solution to a target position, the stage 12 may be moved, or the spray device 15 may be moved. Both the stage 12 and the spray device 15 may move. Furthermore, the stage 12 may not only move in the X and Y directions shown in FIG. 6 but also be inclined at a predetermined angle from the horizontal plane.

Further, the base material, the solution for forming the metal oxide film, and the heating temperature of the base material used in the present invention are the same as those described in the above-mentioned “A. Method for producing metal oxide film”. Explanation here is omitted.
Hereinafter, the metal oxide film manufacturing apparatus of the present invention will be described for each configuration.

1. Spray Device The spray device used in the present invention is a device that does not use air to atomize the metal oxide film forming solution. Examples of such a spray device include those similar to the spray device described in “A. Method for Producing Metal Oxide Film”, and the description thereof is omitted here.

2. Stage The stage used in the present invention is used for holding a substrate. The stage used in the present invention is not particularly limited as long as it has sufficient heat resistance with respect to the heating temperature of the substrate described above. In addition, the stage used in the present invention may be provided with a cooling mechanism in order to cool the substrate and the stage heated by the heating device described later.

3. Heating device The heating device used in the present invention is a device that heats the base material to a temperature equal to or higher than the metal oxide film forming temperature. Such a heating device is not particularly limited as long as it can heat the substrate to a desired temperature. For example, the atomized metal oxide film forming solution and the substrate An apparatus for heating the substrate while contacting the substrate, or an apparatus for heating the substrate in advance before bringing the atomized metal oxide film forming solution into contact with the substrate. In particular, the former heating device is preferable. This is because the substrate temperature can be stably maintained. Examples of the former heating device include a hot plate and an infrared lamp, and among these, a hot plate is preferable. The shape of the hot plate can be arbitrarily selected according to the shape of the base material, and specific examples thereof include a flat plate type and a cylindrical type. Examples of the latter heating device include a hot air blower, an oven, and a firing furnace. As a method of using the heating apparatus used in the present invention, for example, the same method as that described in “A. Method for producing metal oxide film 4. Contact method” can be given. Description is omitted.

  Moreover, in this invention, the said heating apparatus may be provided with the function of the said stage. For example, when a hot plate is used as a heating device, the substrate can be heated and provided with a stage function for holding the substrate.

4). Metal Oxide Film Forming Solution Supply Device The metal oxide film forming solution supply device used in the present invention is a device for supplying a metal oxide film forming solution to the spray device. The metal oxide film forming solution supply device used in the present invention is particularly suitable if it is filled with the metal oxide film forming solution and can supply the metal oxide film forming solution to the spray device in a desired amount. It is not limited.

  Further, the metal oxide film forming solution supply apparatus used in the present invention has a stirring function for keeping the metal oxide film forming solution uniform and a temperature adjusting function for adjusting the liquid temperature of the metal oxide film forming solution. Etc. may be included.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be specifically described with reference to examples.

[Example 1]
In this example, an experiment for applying an ITO transparent electrode film was performed.
First, 10 g of hydrogen peroxide solution was added to 1000 g of an ethanol-water mixed solution (ethanol: water = 1: 1) of indium chloride 0.1 mol / l and tin chloride 0.05 mol / l to obtain a metal oxide. A film forming solution was obtained.
Next, the glass substrate is heated to 350 ° C. with a hot plate (manufactured by AS ONE), and the metal oxide film forming solution is airless sprayed onto the substrate (A7A airless auto gun, cross-cut nozzle 1/12, nozzle diameter). The metal oxide film was formed by spraying using 114 μm (manufactured by Nordson), and an ITO film was obtained on the substrate.
When the metal oxide film obtained by the above method was measured using an X-ray diffractometer (Rigaku, RINT-1500), it was confirmed that an ITO film was formed. Furthermore, when the surface resistance of the ITO film provided on the glass substrate was measured using Loresta (manufactured by Mitsubishi Chemical Corporation), it was 1Ω / □. Furthermore, when HAZE (turbidity) was determined by a color computer & haze meter (manufactured by Suga Test Instruments Co., Ltd.), it was 3% and the total light transmittance was 90%. When the cross section was measured with a scanning electron microscope (SEM), the film thickness was 520 nm.

[Example 2]
In this example, instead of the airless spray used in Example 1, an ITO film was formed in the same manner as in Example 1 except that a rotary atomizing spray (RA-20 rotary atomizer, manufactured by Nordson) was used. Obtained. When the metal oxide film obtained by the above method was measured using an X-ray diffractometer (Rigaku, RINT-1500), it was confirmed that an ITO film was formed. Furthermore, when the surface resistance of the ITO film provided on the glass substrate was measured using Loresta (manufactured by Mitsubishi Chemical Corporation), it was 1Ω / □. Furthermore, when HAZE was calculated | required with the color computer & haze meter (made by Suga Test Instruments Co., Ltd.), it was 4% and the total light transmittance was 90%. When the cross section was measured with a scanning electron microscope (SEM), the film thickness was 550 nm.

[Comparative Example 1]
In this comparative example, an ITO film was obtained in the same manner as in Example 1 except that air spray (A7A type 2 fluid spray gun, manufactured by Nordson) was used instead of the airless spray used in Example 1. It was. When the metal oxide film obtained by the above method was measured using an X-ray diffractometer (Rigaku, RINT-1500), it was confirmed that an ITO film was formed. Furthermore, when the surface resistance of the ITO film provided on the glass substrate was measured using Loresta (manufactured by Mitsubishi Chemical Corporation), it was 20Ω / □. Furthermore, when HAZE was calculated | required with the color computer & haze meter (made by Suga Test Instruments Co., Ltd.), it was 35%, and HAZE was a high value compared with Example 1 and Example 2. The total light transmittance was 85%. When the cross section was measured with a scanning electron microscope (SEM), the film thickness was 530 nm.

It is explanatory drawing which shows an example of the manufacturing method of the metal oxide film of this invention. It is a relationship figure (Pourbaix diagram) which shows the relationship between pH and electric potential with respect to cerium. It is explanatory drawing which shows the other example of the manufacturing method of the metal oxide film of this invention. It is explanatory drawing which shows the other example of the manufacturing method of the metal oxide film of this invention. It is explanatory drawing which shows the other example of the manufacturing method of the metal oxide film of this invention. It is explanatory drawing which shows an example of the manufacturing apparatus of the metal oxide film of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Spray apparatus 2 ... Metal oxide film formation solution 3 ... Base material 4 ... Metal oxide film 5-7 ... Roller

Claims (3)

Using a spray device, the metal oxide film forming solution in which a metal salt or metal complex is dissolved as a metal source is atomized, and the atomized solution for forming the metal oxide film and a temperature equal to or higher than the metal oxide film forming temperature A method for producing a metal oxide film, wherein a metal oxide film is obtained on the substrate by contacting the heated substrate,
Said spray device, Ri apparatus der method that does not use air for atomizing the metal oxide film-forming solution,
The metal oxide film forming solution contains at least one of an oxidizing agent and a reducing agent,
The metal oxide film-forming temperature, method for producing a metal oxide film, characterized in der Rukoto the range of 300 to 400 ° C..   The method for producing a metal oxide film according to claim 1, wherein the spray device is an airless spray or a rotary atomizing spray.   The method for producing a metal oxide film according to claim 1, wherein the metal oxide is indium tin oxide.

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