JP4770239B2 - Method for producing metal oxide film - Google Patents

Description

  The present invention relates to a method for manufacturing a metal oxide film in which a metal oxide film is formed while mixing an oxidizing gas.

  Conventionally, it has been known that metal oxide films exhibit various excellent physical properties. Taking advantage of these properties, metal oxide films have been used in a wide range of fields such as transparent conductive films, optical thin films, and fuel cell electrolytes. Examples of the method for producing such a metal oxide film include a sol-gel method, a sputtering method, a CVD method, a PVD method, and a printing method, and these methods all require firing and a high vacuum state. Therefore, there is a problem that the apparatus becomes large, and the cost is high and the operability is complicated.

  Another problem in the method for producing a metal oxide film is that it is difficult to provide a uniform metal oxide film on a substrate having a structure. For example, in the sputtering method, shape followability is poor due to its principle, and in the printing method, it is difficult to form a film on a structure portion smaller than the ceramic fine particles contained in the ink. In addition, the CVD method, which is considered to be relatively excellent in shape followability, is effective for simple and shallow grooves, but a uniform metal oxide film is used for complicated structures. It was difficult to provide.

  In order to solve such a problem, a soft solution process in which a metal oxide film is directly formed on a substrate from a solution has been proposed (Non-patent Document 1). Such a soft solution process normally does not require firing or a high vacuum state, and thus can solve the problems such as the enlargement of the apparatus described above. Further, since the base material is brought into contact with the metal oxide film forming solution, even if the base material has a complicated structure portion, the solution can easily enter the structure portion, and a uniform metal oxide can be obtained. A membrane is obtained.

  As an attempt to use such a soft solution process, for example, in Patent Document 1, a reaction solution containing a constituent element of a thin film to be formed between an anode electrode and a cathode electrode to which a predetermined voltage is applied is specified. A method of forming a thin film by flowing at a flow rate is disclosed. However, in Patent Document 1, the substrate is limited to the conductor, and the film quality of the obtained thin film is coarse in particle nature.

  For example, Patent Document 2 and Patent Document 3 disclose a method of immersing a substrate treated with an Ag catalyst or a Pd catalyst in a zinc oxide deposition solution to form a zinc oxide film by an electric field-free method. ing. In these patent documents, a reducing agent such as dimethylamine borane is used. However, such a reducing agent has high reactivity, and it may be difficult to control the reaction.

Resources and materials Vol. 116 p. 649-655 (2000) Japanese Patent No. 3353070 JP 2000-8180 A JP 2000-336486 A

  The present invention has been made in view of the above problems, and is a method for producing a metal oxide film that forms a metal oxide film on the surface of a substrate, where the substrate has a complicated structure. Another object of the present invention is to provide a method for producing a metal oxide film capable of obtaining a uniform metal oxide film by a simple process.

  In order to solve the above-mentioned problems, the present invention provides a metal oxide film obtained by bringing a metal oxide film forming solution in which a metal salt or a metal complex is dissolved as a metal source into contact with a substrate surface. The method for producing a metal oxide film is characterized in that the substrate surface and the metal oxide film forming solution are contacted in the presence of an oxidizing gas.

  According to the present invention, by using an oxidizing gas, the oxidizing gas directly oxidizes metal ions in the metal oxide film forming solution to increase the valence of the metal ions, thereby forming the metal oxide film. It can be an easy environment In addition, according to the present invention, since the metal oxide film is obtained directly from the solution by bringing the base material and the metal oxide film forming solution into contact with each other, treatment such as firing or high vacuum is performed. The process is simple and the cost can be reduced. Furthermore, even when the substrate has a complicated structure portion, the solution can easily penetrate into the structure portion, so that there is an advantage that a uniform metal oxide film can be obtained.

  Moreover, in the said invention, it is preferable that the said oxidizing gas is oxygen or ozone. This is because it is easy to obtain industrially and can reduce the cost.

  Moreover, in the said invention, before making the said base material surface and the said solution for metal oxide film formation contact, the catalyst process which provides the catalyst layer which accelerates | stimulates the production | generation of a metal oxide film on the said base material surface is performed. Is preferred. This is because the metal oxide film can be efficiently formed in a short time by providing the catalyst layer.

In the above invention, the catalyst layer is, Sn metal, Pd metal, Ag metal, preferably contains at least one selected from the group consisting of TiO ₂ and carbon. This is because by providing the catalyst layer containing the above compound, the metal oxide film can be efficiently formed particularly in a short time.

  Moreover, in the said invention, the metal source used for the said solution for metal oxide film formation is Ca, Sr, Ba, Sn, Pb, Bi, Ti, V, Cr, Mn, Fe, Cu, Ni, Mo, It is preferable to contain at least one metal element selected from the group consisting of Rh, Pd, Ag, Ce, Pr, and Pu. The metal element has a metal oxide region in the Pourbaix diagram, and the valence of the metal in the metal oxide state is higher than the valence of the metal ions present in the metal oxide film forming solution. Therefore, it is suitable as a main constituent element of the metal oxide film obtained by the present invention.

  Moreover, in the said invention, it is preferable that the said solution for metal oxide film formation contains at least one of an oxidizing agent and a reducing agent. This is because the deposition rate of the metal oxide film can be improved by using the oxidizing agent and the reducing agent.

  Moreover, in the said invention, the said oxidizing agent consists of chlorate ion, perchlorate ion, chlorite ion, hypochlorite ion, bromate ion, hypobromate ion, nitrate ion, and nitrite ion. It preferably contains at least one ionic species selected from the group. This is because the ionic species can increase the valence of metal ions and provide an environment in which a metal oxide film can be easily formed as in the equilibrium reaction described later.

  The present invention has an effect that a metal oxide film can be formed on the surface of a substrate, and a uniform metal oxide film can be obtained by a simple process even when the substrate has a complicated structure. It is what you play.

  Hereinafter, the manufacturing method of the metal oxide film of this invention is demonstrated in detail.

  The method for producing a metal oxide film of the present invention comprises a metal oxide film obtained by bringing a metal oxide film-forming solution in which a metal salt or a metal complex is dissolved as a metal source into contact with a substrate surface. The method is characterized in that the substrate surface and the metal oxide film forming solution are contacted in the presence of an oxidizing gas. In addition, when the base material used for this invention is a porous base material, a metal oxide film is formed in the outer surface and inside of a porous base material.

In the present invention, for example, a non-metallic property can be imparted to a metal substrate that has been finely processed. Specifically, it is possible to provide insulation, and it can be used at a higher temperature than the conventional resin insulation method. Furthermore, since the metal oxide film manufactured by such a method has excellent adhesion to the metal substrate and is dense, the conventional insulation method using a resin requires a film thickness of about 10 μm. Even a metal oxide film having a thickness of about 1 μm can provide the same insulating property.
Moreover, in this invention, corrosion resistance can be provided with respect to the metal base material which gave the microfabrication, for example. Specifically, by forming a metal oxide film that is resistant to acids and alkalis and that has electrical conductivity, it is possible to obtain a usable member even in an environment that cannot be used only with metal. it can. Furthermore, in the present invention, since the colored metal oxide film having the above corrosion resistance can be obtained, it can be used for a member requiring design properties, specifically, a member for measures against acid rain in a building or a plant. it can.
The present invention can also be applied to a resin base material or the like that has been subjected to fine processing. By using the present invention, an inexpensive and easy-to-process resin can be finely processed to impart organic solvent resistance, hydrophilicity, and biocompatibility, so that an organic solvent plant, organic solvent container, biochip, physics and chemistry equipment Can be used in general.
In addition, since the present invention makes it possible to obtain a metal oxide film at a low temperature as compared with a conventional method for producing a metal oxide film, a non-heat-resistant substrate such as resin or paper can be used. For example, a wide range of application capabilities can be demonstrated for electronic devices that are becoming smaller, energy-related devices that are integrated, and bio fields that are diversifying.

Next, the mechanism of the method for producing a metal oxide film of the present invention will be described using a case where a cerium oxide (CeO ₂ ) film is formed using cerium chloride (CeCl ₃ ) as a metal source and oxygen as an oxidizing gas. To do.
The cerium oxide film is not yet clear, but is considered to be formed by the following five equations.
(I) CeCl ₃ → Ce ³⁺ + 3Cl ⁻
(Ii) 2H ₂ O + O ₂ + 4e ^{− ４} 4OH ⁻
(Iii) Ce ³⁺ → Ce ⁴⁺ + e ⁻
(Iv) Ce ⁴⁺ + 2OH ⁻ → CeO ₂ + 2H ⁺
(V) 2H ⁺ + 2OH ⁻ → 2H ₂ O

  Such a mechanism will be specifically described with reference to the drawings. First, as shown in FIG. 1 (a), cerium chloride is dissolved in water as a solvent to prepare a metal oxide film forming solution 1, and oxygen, which is an oxidizing gas, is bubbled into this solution. The base material 2 is immersed. At this time, cerium chloride becomes cerium ion in the aqueous solution (formula (i)). Subsequently, as shown in FIG. 1B, oxygen, which is an oxidizing gas, acquires electrons by an equilibrium reaction to generate hydroxide ions (formula (ii)). At that time, as shown in FIG. 1C, electrons supplied to oxygen are provided by changing trivalent cerium ions into tetravalent cerium ions (formula (iii)). Since tetravalent cerium ions can exist only as cerium oxide as can be seen from the Pourbaix diagram, as shown in FIG. 1 (d), they react immediately with the hydroxide ions in the above solution and cerium oxide. (Equation (iv)). Hydrogen ions generated at this time react with hydroxide ions in the solution to form water (formula (v)). As a result of these reactions, the metal oxide film forming solution continues to be deficient in hydroxide ions. In the equilibrium reaction of formula (ii), a rightward driving force always acts, and FIG. As shown in e), the cerium oxide film 3 is formed by a chain reaction in which electrons are supplied from trivalent cerium ions.

Moreover, FIG. 2 is a pool diagram of cerium. When the above reaction is oxidized with Ce ^{3+ and} Ce ⁴⁺ , tetravalent cerium can exist only as CeO ₂ . Can think. From this, it is considered that a metal oxide film can be similarly manufactured by the manufacturing method of the present invention as long as it is a metal element having a similar metal oxide region. Moreover, even if it is a metal element which has a metal hydroxide area | region, a metal oxide film is obtained by heating a metal hydroxide film | membrane. In the present invention, even when an alcohol, an organic solvent, or the like is used as a solvent instead of water, a metal oxide film is formed by a reaction similar to the above reaction or a trace amount of water contained in the solvent. I think that.
Hereafter, the manufacturing method of the metal oxide film of this invention is demonstrated in detail for every structure.

1. Metal Oxide Film Forming Solution First, 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 salt or metal complex as a metal source and a solvent. In the present invention, the metal oxide film forming solution preferably contains at least one of an oxidizing agent and a reducing agent. This is because the deposition rate of the metal oxide film can be improved. In addition, 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.

(1) Metal source First, the metal source used in the present invention will be described. The metal source used in the present invention is dissolved in a metal oxide film forming solution to give a metal oxide film on the substrate surface. 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 concentration of the metal source in the metal oxide film forming solution used in the present invention is usually 0.001 to 1 mol / l, particularly 0.01 to 0.1 mol / l when the metal source is a metal salt. When the metal source is a metal complex, it is usually 0.001 to 1 mol / l, and particularly preferably 0.01 to 0.1 mol / l. If the concentration is below the above range, the metal oxide film formation reaction is difficult to occur, and a desired metal oxide film may not be obtained. If the concentration is above the above range, a precipitate is formed. Because there is a possibility.

  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, Ca, Sr, Ba, Sn, Pb, Bi, Ti, V And at least one metal element selected from the group consisting of Cr, Mn, Fe, Cu, Ni, Mo, Rh, Pd, Ag, Ce, Pr, and Pu, among which, Ca, Sr, Sn At least one metal element selected from the group consisting of Pb, Ti, V, Cr, Fe, Cu, Ni, Mo, Pd and Ce is preferable. The above-mentioned metal element has been confirmed by the Pourbaix diagram that the valence when present as a metal oxide is larger than the valence when present as a metal ion, and the main constituent element of the metal oxide film Because it is suitable as.

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 chlorides, nitrates, acetates and the like. This is because these compounds are easily available as general-purpose products.
Specific examples of the metal complex include calcium acetylacetonate dihydrate, calcium di (methoxyethoxide), calcium gluconate monohydrate, calcium citrate tetrahydrate, and calcium salicylate dihydrate. Japanese products, 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 (triethanolamate), dihydroxybis (ammonium lactate) titanium, diisopropoxytitanium bis (ethylacetoacetate), ammonium peroxosocitrate tetrahydrate Dicyclopentadienyl iron (II), iron (II) lactate trihydrate, iron (III) acetylacetonate, nickel (II) acetylacetonate dihydrate, copper (II) acetylacetonate, copper ( II) Dipivaloylmethanate, copper ethylacetoacetate (II), strontium dipivaloylmethanate, tetraethyltin, dibutyltin oxide (IV), tricyclohexyltin (IV) hydroxide, cerium (III) acetylacetonate n-hydrate, lead (II) citrate trihydrate, lead cyclohexanebutyrate, barium lactate, barium stearate, bismuth tris (2,2,6,6-tetramethyl-3,5-heptanedionate), Vanadium oxide acetylacetonate, chromium (III) acetylacetonate, manganese (II) salicylate, tris (acetonitrile) molybdenum tricarbonyl, etc. Can be mentioned. In the present invention, the metal oxide film forming solution may contain two or more of the above metal sources.

(2) Oxidizing agent The metal oxide film forming solution used in the present invention may contain an oxidizing agent. The oxidizing agent used in the present invention has a function of oxidizing metal ions. For example, when a metal ion having a certain valence exists in the solution for forming a metal oxide film and the valence cannot take a form other than the metal ion, the oxidant is used to obtain the valence. The number can be changed to a valence that can exist as a metal oxide film.

  The concentration of the oxidizing agent in the metal oxide film forming solution used in the present invention varies depending on the type of the oxidizing agent, but is usually 0.001 to 1 mol / l, particularly 0.01 to It is preferably 0.1 mol / l.

  The oxidizing agent used in the present invention is not particularly limited as long as it can be dissolved in a solvent described later and promote the formation of a metal oxide film. It preferably contains at least one ionic species selected from the group consisting of chlorate ion, chlorite ion, hypochlorite ion, bromate ion, hypobromate ion, nitrate ion, and nitrite ion, Among these, it is preferable to contain at least one ionic species selected from the group consisting of chlorite ions, hypochlorite ions, and nitrite ions.

The ionic species are considered to cause the following reaction 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 ⁻

  In addition, the oxidizing agent used in the present invention is not particularly limited as long as it can be dissolved in a solvent described later and promote the formation of a metal oxide film. Examples thereof include sodium salts and potassium salts of ionic species, hydrogen peroxide, silver oxide, dichromic acid, and potassium permanganate.

  In the present invention, it is particularly preferable to use sodium chlorite, potassium nitrite, sodium hypochlorite, potassium hypochlorite or sodium nitrite as the oxidizing agent. Moreover, the metal oxide film forming solution used in the present invention may contain two or more kinds of the oxidizing agents.

(3) Reducing agent The metal oxide film forming solution used in the present invention may contain a reducing agent. Although the reason for the reducing agent used in the present invention is not clear, it is considered that an environment in which a metal oxide film is easily generated can be obtained from experimental results and the like.

  The concentration of the reducing agent in the metal oxide film forming solution used in the present invention varies depending on the type of the reducing agent, but is usually 0.001 to 1 mol / l, particularly 0.01 to It is preferably 0.1 mol / l.

  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, sodium borohydride, etc. Among them, it is preferable to use borane complex. .

  Further, the metal oxide film forming solution used in the present invention may contain a reducing agent and an oxidizing agent. Such a combination of a reducing agent and an oxidizing agent is not particularly limited. For example, a combination of hydrogen peroxide or sodium nitrite and an arbitrary reducing agent, or an arbitrary oxidizing agent and a borane complex. The combination etc. are mentioned, Especially, the combination of hydrogen peroxide and a borane-type complex is preferable.

(4) Solvent The solvent used in the present invention is not particularly limited as long as it can dissolve the above-described oxidizing agent and metal source without oxidizing metal ions. When the source is a metal salt, examples thereof include water, methanol, ethanol, isopropyl alcohol, propanol, butanol and other lower alcohols having a total carbon number of 5 or less, and mixed solvents thereof. In the case, water, the lower alcohol mentioned above, and these mixed solvents can be mentioned. 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, but water In the case of using an oxidizing 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 an additive such as a surfactant. The surfactant acts on the interface between the metal oxide film forming solution and the substrate surface, and has a function of facilitating the formation of the metal oxide film. The amount of the surfactant used is preferably selected and used in accordance with the type of metal source 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.

2. 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, and for example, glass, plastic, resin, metal, alloy, semiconductor, ceramics, paper, cloth, etc. can be used. The material of the base material is preferably selected as appropriate in consideration of functions such as corrosion resistance, insulation and hydrophilicity imparted by the metal oxide film, usage of the member, and the like.

  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. Those having a flow path, porous, and having a porous film may be used. Among them, in the present invention, it is preferable that the substrate has a fine structure, is porous, and is provided with a porous film. This is because the solution for forming a metal oxide film can penetrate into the inside of the base material, and a metal oxide film having good shape following ability can be obtained.

  Moreover, it is preferable that the base material used for this invention has the catalyst layer which accelerates | stimulates the production | generation of a metal oxide film on the surface. By providing the catalyst layer, the surface of the substrate can be activated, and as a result, the generated metal oxide nuclei can be easily adsorbed. The catalyst treatment for providing the catalyst layer on the substrate surface is usually performed before the substrate surface and the metal oxide film forming solution are brought into contact with each other.

The material constituting the catalyst layer is not particularly limited as long as it can promote the formation of a metal oxide film. Specifically, Sn metal, Pd metal, Ag metal, TiO are used. _And at least one selected from the group consisting of ₂ and carbon. The carbon used in the present invention is not particularly limited as long as it can promote the formation of a metal oxide film, and specific examples include carbon fine particles, carbon nanotubes, fullerenes and the like. Among these, carbon fine particles are preferable.

  Further, the film thickness of the catalyst layer is not particularly limited as long as the generation of the metal oxide film can be promoted, but specifically, it is 100 nm or less, particularly in the range of 1 to 50 nm, It is preferable to be in the range of 1 to 10 nm.

  Further, the catalyst layer may completely cover the substrate surface, or may partially cover the substrate surface. Examples of the catalyst layer partially covering the substrate surface include a catalyst layer present in a pattern on the substrate surface.

  The method for forming the catalyst layer is not particularly limited as long as it can provide a catalyst layer that can promote the formation of a metal oxide film. Examples thereof include an electroplating method, an electroplating method, a coating method, and an immersion method.

  Specifically, the electroless plating methods include Melplate ITO process, Melplate G-Si process (Meltex Co., Ltd.), MOON process (Okuno Pharmaceutical Co., Ltd.), Black Hole Process (Nippon McDermid). And the like). Specific examples of the electroplating method include a method using a Pt ion solution, a Sn ion solution, a Pd ion solution, an Ag ion solution, and the like.

  Specific examples of the coating method or the dipping method include PM-A200, PM-20os (manufactured by Nikko Materials Co., Ltd.), MK-2605 (Muromachi Chemical Co., Ltd.), P-25 (Nippon Aerosil). And the like using a solution in which fine particles such as) are dispersed in a solvent.

3. Next, a contact method between the substrate and the metal oxide film forming solution in the method for producing a metal oxide film of the present invention will be described. The method for producing a metal oxide film of the present invention is characterized in that the substrate surface and the metal oxide film forming solution are brought into contact in the presence of an oxidizing gas.

  First, the oxidizing gas used in the present invention will be described. The oxidizing gas used in the present invention is not particularly limited as long as it has an oxidizing ability, and examples thereof include oxygen, ozone, nitrous acid gas, nitrogen dioxide, chlorine dioxide, and halogen gas. Of these, oxygen and ozone are preferably used, and ozone is particularly preferably used. This is because it is easy to obtain industrially and can reduce the cost. In the present invention, the oxidizing gas may be diluted with an inert gas such as nitrogen or a rare gas in order to adjust the reactivity or the like of the oxidizing gas. At this time, the concentration of the oxidizing gas varies greatly depending on the kind of the oxidizing gas, but specifically, it is preferably in the range of 10 to 100%, more preferably in the range of 20 to 50%. .

  In the present invention, “in the presence of oxidizing gas” means a state in which the oxidizing gas can act on the contact portion between the substrate surface and the metal oxide film forming solution. is there. Specifically, a method of bringing an oxidizing gas into a space at a constant concentration and bringing the base material and the metal oxide film forming solution into contact with each other in an oxidizing gas atmosphere, and jetting the oxidizing gas And a method of bringing an oxidizing gas, a base material and a metal oxide film forming solution into contact with each other.

  A method for bringing the oxidizing gas, the base material and the metal oxide film forming solution into contact with each other by injecting the oxidizing gas is not particularly limited. For example, the oxidizing gas is injected from the gas phase. Examples thereof include a method of contacting, a method of injecting an oxidizing gas into the liquid phase, and contacting as bubbles of the oxidizing gas. The method of injecting and contacting the oxidizing gas from the gas phase is a method of injecting the oxidizing gas from the gas phase to the contact portion between the substrate surface and the metal oxide film forming solution using a gas injection device or the like. It is. At this time, the liquid film of the metal oxide film forming solution on the substrate surface is preferably thin. Although it does not specifically limit as a gas-injection apparatus used for the said method, For example, a blower knife (made by Spraying Systems Japan Co., Ltd.) etc. can be mentioned.

  The method of injecting and contacting the oxidizing gas from the gas phase can be used, for example, when a metal oxide film is formed by a roll coating method. Specifically, for example, as shown in FIG. 3, by passing the base material 1 between the roll 4 and the roll 5 and further injecting the oxidizing gas 8 from the gas phase using the gas injection device 7, A method of forming a metal oxide film on the surface of the substrate is mentioned, which is suitable for the production of a continuous metal oxide film.

  On the other hand, the method of injecting the oxidizing gas into the liquid phase and bringing it into contact with bubbles uses a gas injection device, injecting the oxidizing gas into the metal oxide film forming solution, and forming the bubbles of the oxidizing gas into the base material. In this method, the surface is brought into contact with the contact portion between the metal oxide film forming solution. At this time, the bubbles of the oxidizing gas are preferably small. This is because the surface area of the bubbles is increased, and the metal oxide film is formed efficiently. Although it does not specifically limit as a gas injection apparatus used for the said method, For example, a bubbler etc. can be mentioned. Examples of such a bubbler include Naflon bubbler (manufactured by ASONE), microbubble generator BT-50 (manufactured by Bubble Tank), and the like. In the above method, some of the bubbles of the oxidizing gas may be dissolved in the metal oxide film forming solution.

  The method of injecting the oxidizing gas into the liquid phase and bringing it into contact as bubbles can be used, for example, when a metal oxide film is formed by a dipping method or a single-wafer method. As a specific example of the dipping method, for example, as shown in FIG. 4A, the entire base material 2 is immersed in the metal oxide film forming solution 1, and the oxidizing gas 8 is oxidized using the gas injection device 7. Examples thereof include a method of spraying into the material film forming solution 1 to form a metal oxide film on the entire surface of the substrate 2. Although not shown in FIG. 4A, a patterned metal oxide film can be provided on the surface of the substrate 2 by providing a shielding portion on the surface of the substrate 2. Further, for example, as shown in FIG. 4B, a gas injection device 7 is used to inject an oxidizing gas 8 into the metal oxide film forming solution 1 to form a metal oxide film containing the oxidizing gas 8. By flowing the solution 1 at a constant flow rate, a method of forming a metal oxide film on the inner peripheral surface of the substrate 2 can be exemplified.

  Further, as a specific example of the single-wafer method, for example, as shown in FIG. 5, a gas injection device 7 is used to inject an oxidizing gas 8 into the metal oxide film forming solution 1 to generate an oxidizing gas. The metal oxide film forming solution 1 containing 8 is circulated by the pump 6 and only the base material 2 is heated, thereby promoting the film forming reaction of the metal oxide film in the vicinity of the base material on the surface of the base material. Examples thereof include a method for forming a metal oxide film.

  In the method for producing a metal oxide film of the present invention, when the substrate surface and the metal oxide film forming solution are brought into contact with each other, irradiation with ultraviolet rays, heating, or a combination thereof, The deposition rate of the oxide film can be improved. Hereinafter, these methods will be described.

(1) Improvement of film forming speed by irradiation with ultraviolet rays In the present invention, it is preferable to irradiate ultraviolet rays when the substrate surface and the metal oxide film forming solution are brought into contact with each other. This is because, by irradiating with ultraviolet rays, for example, nitrate ions can be reduced to nitrite ions or perchlorate ions can be reduced to chlorate ions, so that the oxidation of metal ions can be promoted. Furthermore, the crystallinity of the resulting metal oxide film can be improved by irradiation with ultraviolet rays.

The ultraviolet irradiation method is not particularly limited as long as it is a method of irradiating the contact portion between the substrate surface and the metal oxide film forming solution, but for example, when using the above-described immersion method, As shown in FIG. 6, a method of immersing the base material 2 in the metal oxide film forming solution 1 and irradiating ultraviolet rays 9 from the solution side can be mentioned. In this case, from the viewpoint of accurately irradiating ultraviolet rays to the contact portion between the substrate surface and the metal oxide film forming solution, the metal oxide film forming solution existing on the substrate surface irradiated with the ultraviolet rays Is preferably thin.
Moreover, as a wavelength of the said ultraviolet-ray, it is 185-470 nm normally, and it is preferable that it is 185-260 nm especially. Moreover, as an intensity | strength of the ultraviolet-ray used for this aspect, it is 1-20 mW / cm < ² > normally, and it is preferable that it is 5-15 mW / cm < ² > especially.
As an ultraviolet irradiation apparatus that performs such ultraviolet irradiation, a commercially available UV light irradiation apparatus, laser oscillation apparatus, or the like can be used, and examples thereof include HB400X-21 manufactured by SEN Special Light Source Co., Ltd. Can do.

(2) Improvement of film formation rate by heating Moreover, in this invention, when making the base-material surface and the solution for metal oxide film formation contact, it is preferable to heat. This is because the film formation rate can be improved by heating. The method for heating is not particularly limited as long as it can improve the deposition rate of the metal oxide film, but heating the substrate is particularly preferable, and the substrate and the metal oxide are particularly preferable. It is preferable to heat the physical film forming solution.
Such a heating temperature is preferably appropriately selected according to the characteristics of the metal source and the substrate to be used, and specifically, is preferably in the range of 50 to 150 ° C, particularly 70 to 100 ° C. It is more preferable to be within the range.

(3) Combination of means for improving film formation rate As described above, in the present invention, when the substrate surface and the metal oxide film forming solution are brought into contact with each other, irradiation with ultraviolet rays and heating are performed. The deposition rate of the metal oxide film can be improved. In the present invention, it is also possible to combine these two methods. Specifically, when contacting the substrate surface and the metal oxide film forming solution, there is a method of mixing an oxidizing gas, and further irradiating with ultraviolet rays and heating. In the present invention, ultraviolet light irradiation and heating may be performed at the same time in the above combination, and either ultraviolet light irradiation or heating may be performed first, and the other may be performed later.

4). Next, a metal oxide film obtained by the method for producing a metal oxide film of the present invention will be described. Since the method for producing a metal oxide film of the present invention is a wet coating using a metal oxide film forming solution, for example, even when the substrate is a porous substrate or a substrate having a porous body, etc. The metal oxide film forming solution can easily penetrate into the porous body and the like, and a uniform metal oxide film can be obtained.
Further, the metal oxide film obtained by the method for producing a metal oxide film of the present invention has a porous base material, a base layer for a base material having a porous body and the like, which is usually difficult to obtain a dense metal oxide. By using the metal oxide formed as the base layer as a crystal nucleus and then growing the crystal nucleus using a method for producing an arbitrary metal oxide film, A dense metal oxide film having a sufficient thickness can be provided. As a method for growing such crystal nuclei, a general method for producing a metal oxide film can be used. For example, a vacuum deposition method, a sputtering method, a PVD method such as an ion plating method, plasma CVD, thermal CVD methods such as CVD and atmospheric pressure CVD can be used.

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 and dried.
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.
The metal oxide film may be dried by leaving it at room temperature, or may be dried in an oven or the like.

  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]
<Cerium oxide film formation on porous alumina particle layer>
A glass substrate on which a porous alumina particle layer is provided by applying a 20 wt% solution of alumina fine particles (manufactured by Micron, particle size 30 μm) on a glass substrate by a bar coating method and firing at 500 ° C. for 2 hours. Got.
Next, it was dissolved in 1000 g of an aqueous solution of 0.03 mol / l cerium chloride to obtain a metal oxide film forming solution.
Next, the substrate was immersed in the metal oxide film forming solution at a constant temperature of 70 ° C. At this time, the metal oxide film forming solution was circulated and passed through a filter to eliminate precipitates and contaminated dust. Furthermore, oxygen gas was supplied at 10 ml / min as an oxidizing gas to such a base material, and a reaction was performed for 10 hours to obtain a metal oxide film on the base material. Thereafter, it was washed with pure water and dried at 100 ° C. for 1 hour.
When the metal oxide film obtained by the above method was measured using an X-ray diffractometer (Rigaku, RINT-1500), it was confirmed that a CeO ₂ film was formed. Further, when the CeO ₂ film was measured using an electron beam microanalyzer (JXA-8900R, manufactured by JEOL), CeO ₂ was found not only on the surface of the porous alumina particle layer but also inside (glass substrate contact portion). It was confirmed that it reached. At this time, a larger amount of cerium element was detected on the surface of the porous alumina particle layer than on the inside, and therefore the cerium abundance was different between the inside and the surface portion. It was also confirmed that the porous alumina particle layer was completely covered with the CeO ₂ film.

[Comparative Example 1]
<Silicon oxide film formation on porous alumina particle layer by CVD method>
Using the glass substrate provided with the porous alumina particle layer used in Example 1, a metal oxide film was obtained on the porous alumina particle layer using the CVD method. The conditions of the CVD method were an applied power of 1.0 kW, a film forming pressure of 40 Pa, a hexamethyldisilazane flow rate of 40 sccm, an oxygen gas flow rate of 0.5 slm, and a film forming substrate surface temperature (film forming temperature) of 30 ° C.
When the metal oxide film obtained by the above method was measured using the X-ray diffractometer, it was confirmed that a silicon oxide film was formed. However, when the silicon oxide film was measured using the electron beam microanalyzer, silicon oxide was present on the surface of the porous alumina particle layer, but was present inside the porous alumina particle layer. And did not show sufficient shape following ability. Further, the porous alumina particle layer was not completely covered with the silicon oxide film.

[Example 2]
<Nickel oxide film formation on acrylic substrate with fine processing>
In this example, the object was to impart hydrophilicity by forming a nickel oxide film on an acrylic base material subjected to fine processing.
First, in this example, an acrylic base material (thickness 5 mm) subjected to mechanically provided fine processing (groove: width 500 μm, length 100 mm, depth 50 μm) was used as the base material.
Next, nickel nitrate (manufactured by Kanto Chemical Co., Inc.) is dissolved in 1000 g of a mixed solvent prepared so that water and methanol have a ratio of 1: 1 so that the concentration is 0.01 mol / l. Obtained.
Next, the substrate was immersed in the metal oxide film forming solution at a constant temperature of 80 ° C. At this time, the metal oxide film forming solution was circulated and passed through a filter to eliminate precipitates and contaminated dust. At this time, ozone gas as an oxidizing gas was mixed at 10 ml / min using a Naflon bubbler (manufactured by ASONE). Furthermore, by irradiating such a base material with an ultraviolet intensity of 80 mW / cm ² using an ultraviolet irradiation device (HB400X-21, manufactured by SEN Special Light Source Co., Ltd.), a metal oxide film is formed on the base material. Got. Thereafter, it was washed with pure water and dried at 100 ° C. for 1 hour.
When the metal oxide film was measured using the X-ray diffractometer, it was confirmed that a nickel oxide film was formed. Further, when the water contact angle of the nickel oxide film was measured, it was 25 °, and hydrophilicity was confirmed. The water contact angle of the titanium oxide film was measured using a contact angle measuring device (CA-Z type manufactured by Kyowa Interface Science Co., Ltd.) (30 seconds after dropping a droplet from a microsyringe). It is obtained from.

[Example 4]
<Formation of lead oxide film on glass substrate>
In this example, the object was to impart hydrophilicity by forming a lead oxide film on a glass substrate subjected to a catalyst treatment.
First, a Pd catalyst layer was formed on the surface of the glass substrate. For the formation of the catalyst layer, Melplate ITO process manufactured by Meltex Co., Ltd. was used. First, Mel Cleaner ITO 170 was dissolved in pure water (15 g / L), and the glass substrate was immersed for 10 minutes at a constant temperature of 60 ° C. Next, 20 g of Melplate ITO Conditioner 480A and 200 ml of Melplate ITO Conditioner 480B were added to 1 L of pure water, and the glass substrate was immersed for 5 minutes at a constant temperature of 30 ° C. Subsequently, 30 ml of Melplate Activator 7331 and 1.5 ml of 0.1 mol / L potassium hydroxide solution were added to 1 L of pure water, and the glass substrate was immersed for 5 minutes at a constant temperature of 20 ° C. Thereafter, 10 ml of Melplate PA-7340 was added to 1 L of pure water and immersed for 30 seconds at a constant temperature of 20 ° C. In this way, a glass substrate with Pd catalyst was obtained.
Next, the process of providing a lead oxide film on such a glass substrate with Pd catalyst will be described below. In 1000 g of a mixed solvent prepared so that water and methanol are 1: 1, lead nitrate (II) (manufactured by Kanto Chemical Co., Inc.) is dissolved to 0.01 mol / l, and a metal oxide film forming solution is prepared. Obtained.
Next, the glass substrate with Pd catalyst was immersed in the metal oxide film forming solution at a constant temperature of 80 ° C. At this time, the metal oxide film forming solution was circulated and passed through a filter to eliminate precipitates and contaminated dust. Further, ozone gas as an oxidizing gas was mixed at 10 ml / min using a Naflon bubbler (manufactured by ASONE). In this state, the reaction was carried out for 5 hours, and a metal oxide film was obtained on the glass substrate with Pd catalyst. Thereafter, it was washed with pure water and dried at 100 ° C. for 1 hour.
When the metal oxide film was measured using the X-ray diffractometer, it was confirmed that a lead oxide film was formed. Moreover, when the contact angle of water of the lead oxide film was measured, it was 10 °, and hydrophilicity was confirmed. The water contact angle of the titanium oxide film was measured using a contact angle measuring device (CA-Z type manufactured by Kyowa Interface Science Co., Ltd.) (30 seconds after dropping a droplet from a microsyringe). It is obtained from.

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

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Metal oxide film formation solution 2 ... Base material 3 ... Cerium oxide film 4, 5 ... Roller 6 ... Pump 7 ... Gas injection apparatus 8 ... Oxidizing gas 9 ... Ultraviolet

Claims (7)

A metal oxide film that obtains a metal oxide film without irradiating a laser beam having a wavelength of 400 nm or less by bringing a metal oxide film-forming solution in which a metal salt or metal complex is dissolved as a metal source into contact with the substrate surface A manufacturing method of
The substrate surface and the metal oxide film forming solution are contacted in the presence of an oxidizing gas, and the oxidizing gas directly oxidizes metal ions in the metal oxide film forming solution. all SANYO obtain a metal oxide film,
The metal source used for the said metal oxide film formation solution does not contain Fe , The manufacturing method of the metal oxide film characterized by the above-mentioned.   The method for producing a metal oxide film according to claim 1, wherein the oxidizing gas is oxygen or ozone.   The catalyst treatment for providing a catalyst layer for promoting the formation of a metal oxide film on the surface of the substrate is performed before bringing the substrate surface and the metal oxide film forming solution into contact with each other. Or the manufacturing method of the metal oxide film of Claim 2. 4. The method for producing a metal oxide film according to claim 3, wherein the catalyst layer contains at least one selected from the group consisting of Sn metal, Pd metal, Ag metal, TiO ₂ and carbon. Metal sources used in the metal oxide film forming solution are Ca, Sr, Ba, Sn, Pb, Bi, Ti, V, Cr, Mn, Cu , Ni, Mo, Rh, Pd, Ag, Ce, and Pr. 5. The method for producing a metal oxide film according to claim 1, further comprising at least one metal element selected from the group consisting of Pu and Pu.   The method for producing a metal oxide film according to any one of claims 1 to 5, wherein the metal oxide film forming solution contains at least one of an oxidizing agent and a reducing agent.   The oxidizing agent is at least one selected from the group consisting of chlorate ions, perchlorate ions, chlorite ions, hypochlorite ions, bromate ions, hypobromate ions, nitrate ions, and nitrite ions. The method for producing a metal oxide film according to any one of claims 1 to 6, comprising one ionic species.

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