JP2010093165A - Manufacturing method of electrode, and thin film transistor element and organic electroluminescent element using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a transparent conductive film which has a lower resistance than before and a sufficient surface smoothness in a method for forming a gate electrode by applying a fluid material containing transparent conductive particulate. <P>SOLUTION: A thin film 104" containing metal oxide particulate (indium tin oxide) and a metal oxide precursor is applied onto a glass substrate 106. By irradiating the thin film with microwaves, the precursor serves as a heating element and it is baked so that a conductive thin film is formed. This film is patterned to be a gate electrode 104. Then, a gate insulating film 105 is formed and a semiconductor precursor is applied to it and it is then dried, so that a semiconductor precursor material thin film 101' is obtained. By irradiating it with microwaves, the gate electrode generates heat and the semiconductor precursor material thin film is heated accordingly and is converted to an oxide semiconductor film, so that a semiconductor layer 101 is formed. By evaporation of gold through a mask, source/drain electrodes 102, 103 are formed and thus a thin film transistor is obtained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method of forming an electrode by forming a thin film pattern from metal oxide fine particles and a metal oxide precursor and irradiating an electromagnetic wave from the thin film pattern, and the conductive material obtained by this method. The present invention relates to a thin film transistor element formed using a conductive thin film and an organic electroluminescence element.

ITO (tin-containing indium oxide), SnO ₂ (tin oxide), IZO (zinc-containing indium oxide), and the like have good visible light transparency and visual transparency, and exhibit high conductivity, so liquid crystal displays, touch panels, sensors It is used for solar cells, organic / inorganic electroluminescence, thin film transistors, electronic paper, and the like.

These transparent conductive films can be manufactured by a physical method such as a sputtering method, but this manufacturing method has a demerit that a manufacturing apparatus and a manufacturing cost are increased. On the other hand, a method in which a fine particle dispersion in which transparent conductive fine particles such as ITO, SnO ₂ , IZO, etc. are dispersed in a solvent or the like is applied on a substrate may produce a transparent conductive film at low cost.

  However, a transparent conductive film formed by applying a dispersion on a substrate has a higher resistance than a film manufactured using a physical technique. The reason is that since the transparent conductive film is formed of fine particles, the particle interface increases. Surfactants that adhere to the particle surface for dispersion also increase resistance.

  In order to reduce the resistance of the transparent conductive film, the fine particles may be fired (sintered) at a high temperature. However, the coating film on the resin film cannot be fired at a high temperature and cannot be sufficiently sintered between the fine particles.

  In order to solve this problem, in the manufacturing technique of the transparent conductive film described in Patent Document 1, the coating of transparent conductive fine particles is irradiated with microwaves to perform sintering between particles. When microwaves are used, only the material with a large dielectric loss is not heated, so that the object to be heated itself can be directly and simultaneously heated, and it is expected that the base material has less thermal deterioration than the external heating method.

  However, the resistance of the obtained film is still larger than that obtained by a physical method. Moreover, in the case of a transparent conductive film, transparency will also become low.

  In addition, an attempt has been made to irradiate microwaves after applying pressure to the coating film of transparent conductive fine particles in order to further reduce the resistance (see, for example, Patent Document 2).

However, there is a need for a transparent conductive film with further reduced resistance, and in particular, when it is used as a gate electrode of a thin film transistor, sufficient surface smoothness cannot be obtained.
JP-A-11-242916 JP 2008-91126 A

  The object of the present invention is to produce a transparent conductive film by applying a fluid material such as a dispersion containing transparent conductive fine particles on a substrate to produce a transparent conductive film, which is lower in resistance than conventional and sufficient as a gate electrode of a thin film transistor. It is to obtain a transparent conductive film having surface smoothness, and to obtain an organic electroluminescence element using the transparent conductive film.

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

  1. A method for producing an electrode, comprising: forming a thin film containing at least metal oxide fine particles and a metal oxide precursor on a substrate; and irradiating the thin film with electromagnetic waves to form a conductive thin film.

  2. 2. The method for producing an electrode according to 1 above, wherein the metal oxide fine particles are oxide fine particles containing any of titanium, copper, nickel, zinc, tin and indium.

  3. 3. The method for producing an electrode according to 2 above, wherein the metal oxide precursor contains zinc, tin, indium inorganic acid salt, halide or hydroxide.

  4). 3. The method for producing an electrode according to 2 above, wherein the metal oxide precursor includes a nitrate of any one of zinc, tin and indium.

  5. 5. The method for manufacturing an electrode according to any one of 1 to 4, wherein the thin film is formed by coating.

  6). 6. The method for producing an electrode according to any one of 1 to 5, wherein the electromagnetic wave is a microwave (frequency: 0.3 to 30 GHz).

  7). A thin film transistor element produced by using an electronic circuit pattern formed by the method for producing an electrode according to any one of 1 to 6 above.

  8). 7. An organic electroluminescence device, wherein an anode is formed using the method for producing an electrode according to any one of 1 to 6 above.

  By the coating process, a gate electrode having high smoothness and low resistance, and an electrode useful for an electronic device such as an organic electroluminescence (EL) element can be formed.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

  First, a manufacturing process by applying an electrode according to the present invention will be described.

  Each step of manufacturing the electrode made of the conductive thin film according to the present invention by application using a fluid material will be described below in order.

(Step 1)
A flowable material including transparent conductive particles is prepared.

In the present invention, as the transparent conductive particles, for example, Sn (tin) -containing indium oxide (In ₂ O ₃ (also referred to as ITO)) is dispersed in water or an alcohol-based solvent, whereby a fluid material is used. Create a dispersion. In addition, it is preferable that the particle diameter of transparent electroconductive particle is 100 nm or less.

The metal oxide fine particles used as the transparent conductive particles are oxide particles containing at least one of titanium, copper, nickel, zinc, tin and indium oxide fine particles. For example, the Sn-containing In ₂ described above. Besides O ₃ (ITO), for example, Zn-containing In ₂ O ₃ (IZO), F-containing In ₂ O ₃ (FTO), Sb-containing SnO ₂ (ATO), ZnO, Al-containing ZnO (AZO), Ga-containing ZnO Metal oxide particles such as (GZO), CdSnO ₃ , Cd ₂ SnO ₄ , and TiO ₂ may be used. Moreover, these may be used independently and you may combine 2 or more types arbitrarily. Among these, metal oxides mainly composed of In or Sn are preferable in order to achieve both conductivity and transparency.

  When the transparent conductive fine particles are composed of In and Sn, the Sn content is preferably 20% by mass or less. This is because when the amount of Sn contained in the transparent conductive fine particles increases, carrier scattering occurs and the resistance deteriorates. More preferably, it is 5-15 mass%. This is because if the amount of Sn contained in the transparent conductive fine particles is too small, the carrier density decreases and the resistance deteriorates.

These transparent conductive fine particles are commercially available and can be obtained directly from the market. Examples thereof include NanoTek Slurry ITO, SnO _{2 and the} like manufactured by CI Kasei Co., Ltd.

  The mass ratio of the transparent conductive fine particles to the flowable material is preferably 5 to 50% by mass. More preferably, it is 10-40 mass%. This is because when the mass ratio of the transparent conductive particles to the fluid material is too small, the viscosity of the fluid material becomes too small, and the coating film thickness is applied when the fluid material is applied onto the substrate in step 2 described later. This is because there is a risk of the non-uniformity. Moreover, when the mass ratio of the transparent conductive fine particles to the flowable material becomes too large, the dispersion stability of the fine particles is deteriorated, and the film density after the coating film may be lowered.

  In the present invention, the fluid material (coating liquid) for forming the thin film contains a metal oxide precursor together with the metal oxide fine particles. These precursors preferably contain an inorganic acid salt, halide or hydroxide of zinc, tin and indium. Specific examples include nitrates, sulfates, carbonates, etc., and zinc chloride, tin chloride, indium chloride, and hydroxides thereof.

  Among these, it is preferable that the precursor of a metal oxide contains a nitrate of any metal of zinc, tin, and indium. Specifically, zinc nitrate, tin nitrate, indium nitrate, etc. are raised.

  The amount of these metal oxide precursors contained in the fluid material is in the range of 10 to 90% by mass with respect to the metal oxide fine particles, and these coexist in the coating film, or When these precursors are present on the particle surface or the particle interface, the metal oxide fine particles themselves are also fired and the fusion between the particles is promoted at the time of firing (sintering) by electromagnetic wave irradiation.

(Step 2)
The fluid material prepared in step 1 is applied to the substrate. The substrate is not limited to glass, various ceramic substrates, resin substrates (films) and the like, but resin film substrates are flexible and preferable. For example, a dispersion liquid as a fluid material is applied to a resin film as an example of a transparent substrate. As the transparent substrate, for example, cellulose triacetate, cellulose diacetate, nitrocellulose, polystyrene, polyethylene terephthalate, polyethylene naphthalate, polyimide, or the like can be used as a material. Among these, it is preferable to use polyethylene terephthalate which is excellent in transparency and inexpensive.

  In one embodiment of the present invention, for example, a coating film is formed by applying a metal oxide fine particle dispersion containing a metal oxide precursor as a flowable material on a resin film using a 3 μm applicator. To do. As a method for applying the flowable material to the substrate, besides using an applicator, known methods such as roll coating, screen printing, spray coating, dip coating, and spin coating can be used.

  Alternatively, a method of printing a conductive pattern by an ink jet method or the like may be used.

(Step 3)
In step 3, the coating film applied to the substrate is dried. The drying temperature is preferably set to be equal to or lower than the softening point of the polymer film used as the substrate. Specifically, for example, when polyethylene terephthalate (PET) is used for the film, the drying temperature is preferably set to 80 ° C. or lower.

  Further, as described in JP-A-2008-91126, after the coating film is dried, pressure may be applied to the coating film.

For example, pressure is applied to the surface of the coating film using a roll press or the like so that the density of the coating film is about 3.0 g / cm ³ or more as described in, for example, JP-A-2008-91126.

The linear pressure of the roll press may be 200 kg / cm or more, and thereby, the density of the coating film is set to 3.0 g / cm ³ or more to increase the film density and smooth the coating film surface. In addition, as a method of applying a pressure to a coating film, you may use well-known pressure means, such as a sheet press, for example.

(Step 4)
A transparent conductive film is formed by irradiating the film with electromagnetic waves and sintering transparent conductive fine particles containing a metal oxide precursor of the coating film. In the present invention, it is preferable to use, for example, microwaves (frequency 0.3 to 30 GHz) as electromagnetic waves.

  In the present invention, for example, microwaves having a frequency of 2.45 GHz are irradiated on the coating film at 1000 W for 10 minutes as electromagnetic waves. In this case, if a resin film is used as the substrate, the dielectric loss is small, so that absorption does not occur even when irradiated with microwaves, and the resin film is not heated. On the other hand, since the metal oxide coating film formed on the resin film has a large dielectric loss, heat is generated when it is irradiated with microwaves. Using this, only the coating film on the polymer film can be selectively heated. Moreover, since the oxide coating film has microwave high-speed response performance, the time required to reach the required temperature can be easily controlled by adjusting the heating time and output.

  A method of subjecting the coating film containing the metal oxide fine particles and the metal oxide precursor to microwave irradiation and firing treatment is a method of selectively fusing or advancing the reaction in a short time. It is. However, heat is transferred to the base material not only by heat conduction, so in the case of a base material with low heat resistance such as a resin substrate, the substrate can be controlled by controlling the microwave output, irradiation time, and the number of times of irradiation. It is preferable to perform the treatment so that the temperature is 50 to 200 ° C. and the surface temperature of the thin film containing the precursor is 200 to 600 ° C. The temperature of the thin film surface, the temperature of the substrate, etc. can be measured by a surface thermometer using a thermocouple or a non-contact surface thermometer.

  In the present invention, these microwaves are generally irradiated from the opposite side of the metal oxide coating through the resin substrate.

  Microwaves are generated by a microwave oscillator installed inside and irradiated to the microwave absorption source pattern through the substrate. Examples of the microwave oscillator include Hittite Microwave (2 GHz to 24.8 GHz), Tektrol Cyclotic (voltage controlled crystal oscillator, 40 MHz to 600 MHz), and Modco (voltage controlled oscillator 5 MHz to 6.4 GHz). ), Spinnaker Microwave Co. (1.0 GHz to 20 GHz), etc., and various other types are commercially available and can be used.

(Step 5)
A transparent conductive film is formed on the substrate by the steps 1 to 4 described above.

  According to the above, when manufacturing a transparent conductive film, a fluid material containing transparent conductive fine particles and a precursor of a metal oxide is applied on a substrate to form a coating film, and the coating film is irradiated with electromagnetic waves. Thus, sintering between the transparent conductive fine particles constituting the coating film can be promoted, and it is manufactured by a conventionally known transparent conductive film manufacturing technique in which a fluid material containing transparent conductive fine particles is applied onto a substrate. It becomes possible to produce a transparent conductive film having lower smoothness and better smoothness and lower visible light transparency and visual transparency. As a result, the transparent conductive film having characteristics equal to or better than those of the transparent conductive film manufactured using a physical method such as sputtering is applied to the substrate by applying a fluid material containing transparent conductive fine particles onto the substrate. It becomes possible to manufacture at low cost using the manufacturing method of a conductive film.

  In particular, when tin-containing indium oxide having a particle diameter of 100 nm or less is used as the transparent conductive fine particles, a transparent conductive film having very high visual transparency without causing light scattering in the coating film is obtained. It becomes possible to manufacture. Preferably, the particle size is in the range of 5 nm to 50 nm.

  As described above, according to the present invention, the resistance after applying the transparent conductive fine particle dispersion solvent and sintering the particles is less than 100Ω / □, the haze is less than 2%, the total light transmittance is 85% or more, and the center A transparent conductive film having a line average roughness Ra of 150 nm or less is provided.

  In the above-described embodiment, the case where the fluid material containing the transparent conductive particles is a dispersion liquid has been described. However, the fluid material containing the transparent conductive particles may be, for example, a semi-liquid, a paste, a melt, a solution, or a dispersion. It may be a liquid, suspension or granular material. In addition, as a method for forming a fluid material into a paint, a ball mill, a bead mill, a sand grinder, a paint shaker, or the like can be used. As a solvent into which the transparent conductive particles are mixed when preparing the fluid material, for example, a solvent such as water, alcohol, ketone, ether, ester or the like can be used. In some cases, a surfactant, a binder, or the like may be added.

  In the embodiment described above, the transparent substrate on which the fluid material is applied is a resin film using, for example, cellulose triacetate, cellulose diacetate, nitrocellulose, polystyrene, polyethylene terephthalate, polyethylene naphthalate, polyimide, or the like as a material. However, the transparent substrate on which the flowable material is applied may be a film made of any other material. Further, the substrate to which the fluid material is applied may not be transparent.

  In the above-described embodiment, the case where the coating film is irradiated with a microwave of 2.45 GHz at 1000 W for 10 minutes has been described as an electromagnetic wave, but the frequency of the electromagnetic wave to be irradiated may be 0.3 to 30 GHz. Further, the microwave irradiation input power may be another value such as 500 to 1000 W, for example. If the microwave irradiation time is long, heat is transferred to the substrate and causes damage, so it is preferable to set the microwave irradiation time to 1 to 10 minutes, for example.

  The microwave irradiation may be performed in another atmosphere such as an air atmosphere, a nitrogen atmosphere, an inert atmosphere, or a reducing atmosphere. In addition, when irradiating electromagnetic waves in the air atmosphere, the resistance of the metal oxide precursor of the coating film may deteriorate due to the progress of oxidation and the decrease of carriers in the coating film 2. Caution must be taken. The coating film is preferably irradiated with microwaves in an inert atmosphere or a reducing atmosphere.

  The transparent conductive film formed by the method of the present invention is low in resistance and excellent in surface smoothness, and has a center line average roughness Ra of 150 nm or less and sufficient surface smoothness to be used as a gate electrode of a thin film transistor. Have. Preferably it is the range of 0.1-10 nm.

  Since the precursor itself is also converted into a metal oxide by heat generation, it is considered that this promotes fusion between particles.

  In addition, the measurement of centerline average roughness Ra (micrometer) in this invention was measured using the non-contact three-dimensional surface analyzer (WYKO company RST / PLUS). Ra was defined according to JIS surface roughness (B0601).

  That is, the center line average roughness Ra (μm) of the layer surface was determined for an area of 1.2 mm × 0.9 mm of the formed conductive thin film.

  The transparent conductive film formed by the method of the present invention can be used as a gate electrode of a thin film transistor element or an electrode of an organic EL element or the like.

  If it can be used as a gate electrode of a thin film transistor, a transparent circuit can be assembled, and this can be used as a microwave absorption source (heat generation source) to efficiently assemble a thin film transistor manufacturing process.

  For example, using this as a heat source, the semiconductor precursor can be converted into a semiconductor as described later, used for firing of source and drain electrodes, etc., or applied to the formation of an insulating film.

  A thin film transistor element using a conductive thin film prepared by the method of the present invention as a gate electrode will be described.

  FIG. 1 shows a configuration example of a thin film transistor element.

(Element structure)
1A to 1C show examples of top gate type elements.

  In FIG. 4A, a source electrode 102 and a drain electrode 103 are formed on a support 106, and a semiconductor layer 101 is formed between both electrodes using the source electrode 102 and the drain electrode 103 as a base material (substrate). Then, a gate electrode 104 is formed thereon to form a field effect thin film transistor. FIG. 5B shows an example in which the semiconductor layer 101 formed between the electrodes in FIG. 5A is formed so as to cover the entire surface of the electrode and the support. (C) shows a structure in which the semiconductor layer 101 is first formed on the support 106, and then the source electrode 102, the drain electrode 103, the insulating layer 105, and the gate electrode 104 are formed.

  1D to 1F show an example of a top gate type, and FIG. 1D shows a case where a gate electrode 104 and an insulating layer 105 are formed on a support 106 as shown in the above example, and on that, A source electrode 102 and a drain electrode 103 are formed, and a semiconductor layer 101 is formed between the electrodes. In addition, it is also possible to adopt a configuration as shown in FIGS.

  In these element configurations, the present invention is advantageously applied to the production of a gate electrode.

  FIG. 2 is an equivalent circuit diagram showing an example of a thin film transistor (TFT) sheet in which a plurality of thin film transistors are arranged.

  FIG. 2 shows a thin film transistor sheet 10 in which a plurality of display elements (pixels) or a plurality of thin film transistor elements are arranged on, for example, a plastic sheet (film).

  The thin film transistor sheet 10 has a large number of thin film transistor elements 14 arranged in a matrix. Reference numeral 11 denotes a gate bus line of the gate electrode of each thin film transistor element 14, and reference numeral 12 denotes a source bus line of the source electrode of each thin film transistor element 14. An output element 16 is connected to the drain electrode of each thin film transistor element 14, and the output element 16 is, for example, a liquid crystal or an electrophoretic element, and constitutes a pixel in the display device. In the illustrated example, a liquid crystal is shown as an output element 16 by an equivalent circuit composed of a resistor and a capacitor. 15 is a storage capacitor, 17 is a vertical drive circuit, and 18 is a horizontal drive circuit.

  One embodiment of application of the conductive thin film of the present invention to a gate electrode of a thin film transistor element will be described with reference to FIG. This is only an example, and the present invention is not limited to this.

For example, Sn (tin) -containing indium oxide (In ₂ O ₃ (also referred to as ITO)) fine particles (particle diameter of 100 nm or less) are dispersed in an alcohol solvent, and indium nitrate and tin nitrate (each added to 10% by mass with respect to ITO) The fluid material to which the solution of (1) is added is applied onto a support (eg, a glass substrate) 106 by spin coating (104 ″ represents an application layer). This is irradiated with microwaves (2.45 GHz). Thus, these ITO precursors act as heating elements themselves and are fired catalytically to form a conductive thin film 104 '(FIG. 3 (2)).

  For the ITO thin film, the gate electrode is patterned on the substrate using a photosensitive resist or the like. In FIG. 3, reference numeral 104 denotes a gate electrode made of ITO formed on the substrate 106 (thickness 100 nm) (FIG. 3 (3)).

  Here, the patterning of the conductive thin film 104 ′ may be performed by pattern printing by directly ejecting a fluid material on the substrate in advance by an ink jet method.

  Next, a gate insulating film 105 made of, for example, silicon oxide having a thickness of 200 nm is formed by an atmospheric pressure plasma CVD method or the like (FIG. 3D).

  Next, an example in which an oxide semiconductor layer formed from a precursor is formed as a semiconductor will be described here. That is, a 10% by mass aqueous solution in which indium nitrate, zinc nitrate and gallium nitrate are mixed at a metal ratio of 1: 1: 1 (molar ratio) as a semiconductor precursor is ink-jet-coated on the channel forming portion and dried. Thus, a semiconductor precursor material thin film 101 ′ was obtained (FIG. 3 (5)).

  Thereafter, the substrate is irradiated with microwaves (2.45 GHz) at an output of 500 W, for example, under an atmospheric pressure condition in an atmosphere having a partial pressure of oxygen and nitrogen of 1: 1. Hold at 200 ° C. for 15 minutes while adjusting electromagnetic wave output.

  The semiconductor precursor thin film 101 ′ is heated to a high temperature first by the microwave irradiation, so that the semiconductor precursor thin film 101 ′ on the insulating layer adjacent to the gate electrode is equivalent to the electrode portion. It is heated to a certain degree, undergoes thermal oxidation and is converted into an oxide semiconductor film. Thus, the semiconductor layer 101 is formed (thickness 50 nm) (FIG. 3 (6)).

  Next, by depositing gold through a mask, the source electrode 102 and the drain electrode 103 are formed, whereby a thin film transistor element is formed. The electrode size is, for example, 10 μm wide, 50 μm long (channel width), and 50 nm thick, and the distance between the source electrode and the drain electrode (channel length) is about 15 μm.

  A thin film transistor using an oxide semiconductor using ITO as a gate electrode manufactured by the above method exhibits an n-type enhancement operation.

  As an example, the production of a thin film transistor using an oxide semiconductor has been described. However, the present invention can be applied to a thin film transistor using an organic semiconductor as well as an inorganic semiconductor.

  When a conductive film such as ITO is used for the gate electrode, the semiconductor or electrode precursor can be formed by utilizing the heat generated by electromagnetic wave absorption of the ITO thin film according to the pattern of the gate electrode 4 as described above.

  As with ITO electrode formation, in electromagnetic wave heating such as microwaves, electromagnetic wave (microwave) absorption concentrates on strongly absorbing substances, and the temperature can be raised to 500 to 600 ° C. in a very short time. Therefore, the substrate itself on which the electronic device is formed is hardly affected by heating due to electromagnetic waves, and can only raise the temperature of a substance having an electromagnetic wave absorption capability in a short time. For example, in transistor elements, semiconductor formation or electrode formation is possible. When used, the ITO electrode itself and the adjacent, for example, thin film metal oxide semiconductor precursor material area can be instantaneously heated, which can be quickly converted into a semiconductor or electrode. is there. Further, the heating temperature and the heating time can be controlled by the output of the microwave to be irradiated and the irradiation time, and can be adjusted according to the precursor material and the substrate material.

  In the thin film transistor element of the present invention, in addition to the oxide semiconductor, any known organic or inorganic semiconductor can be used. For example, a vapor deposition film such as pentacene, an organic semiconductor thin film such as a thiophene oligomer, etc. Can be used. In the above example, the creation of the semiconductor layer may be used instead.

  In the present invention, a metal oxide semiconductor is particularly preferable because it is obtained by film formation using a wet process (for example, coating method) of a semiconductor precursor and thermal conversion such as thermal oxidation or plasma oxidation.

  As the oxide semiconductor precursor, it is preferable to use a metal salt selected from nitrate, sulfate, phosphate, carbonate, acetate or oxalate, an organometallic complex, or the like.

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

  In the present invention, these metal salts preferably contain one or more of any of indium (In), tin (Sn), and zinc (Zn), and may be used in combination. .

  Moreover, it is preferable that the other metal contains a salt of either gallium (Ga) or aluminum (Al).

  In the present invention, a metal salt selected from nitrates, sulfates, phosphates, carbonates, acetates or oxalates of the above metals can be suitably used as a precursor, and by using these, carrier mobility can be improved. When a large TFT element is obtained, a metal oxide semiconductor exhibiting good characteristics with a large on / off ratio can be obtained.

  Among the above metal salts, nitrate of nitrate is expected to have particularly low dissociation energy, and among these, nitrate is most preferable.

  Use of these salts is also preferable because the irradiation time can be shortened when the semiconductor conversion process is performed at a substantially low temperature with electromagnetic waves (microwaves).

(Precursor thin film formation method, patterning method)
In order to form a thin film containing a metal salt that is a precursor of these metal oxide semiconductors, a known film formation method, vacuum deposition method, molecular beam epitaxial growth method, ion cluster beam method, low energy ion beam method, An ion plating method, a CVD method, a sputtering method, an atmospheric pressure plasma method and the like can be used. In the present invention, a metal salt selected from the nitrates, sulfates, phosphates, carbonates, acetates or oxalates. It is preferable to continuously coat on a substrate using a solution in which is dissolved in an appropriate solvent, which can significantly improve productivity.

  The solvent for dissolving the metal salt is not particularly limited as long as it dissolves the metal compound to be used, in addition to water, alcohols such as ethanol, propanol and ethylene glycol, ethers such as tetrahydrofuran and dioxane, Esters such as methyl acetate and ethyl acetate, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, glycol ethers such as diethylene glycol monomethyl ether, acetonitrile, and aromatic solvents such as xylene and toluene, hexane, cyclohexane, and tridecane Α-terpineol, alkyl halide solvents such as chloroform and 1,2-dichloroethane, N-methylpyrrolidone, carbon disulfide, and the like can be used. In the present invention, it is preferable to apply using an aqueous solution, that is, a solvent mainly composed of water. The main component of water is that the largest component of the solvent constituting the solution is water, and water accounts for at least 50% by mass, preferably 70% by mass or more of the total solvent. Preferably 80% by mass or more, more preferably 90% by mass is water.

  The metal salts such as nitrates according to the present invention are not decomposable with respect to water and water can be used as a solvent.

  As a method for forming a precursor thin film of a metal oxide semiconductor by applying an aqueous solution containing a metal salt on a substrate, a spray coating method, a spin coating method, a blade coating method, a dip coating method, a casting method, a roll Examples include a coating method, a bar coating method, a die coating method, a mist method, a printing method such as a relief printing plate, an intaglio plate, a lithographic printing method, a screen printing method, and an ink jet printing method in a broad sense. Etc.

  Alternatively, the coating film may be patterned by photolithography, laser ablation, or the like. Among these, the ink jet method, spray coating method, etc. which can apply | coat a thin film are preferable.

(Composition ratio of metal)
In the present invention, it is preferable that indium (In), tin (Sn), zinc (Zn), and other metals containing gallium (Ga) in their composition, and a precursor solution containing these metals as components. In the case of producing, the preferred metal composition ratio is as follows: metal contained in a salt selected from In and Sn metal salts (metal A) and metal contained in a salt selected from metal salts of Ga and Al (metal) It is preferable that the molar ratio (metal A: metal B: metal C) of B) and the metal (metal C = Zn) contained in the metal salt of Zn satisfy the following relational expression.

Metal A: Metal B: Metal C = 1: 0.2-1.5: 1-5
As the metal salt, nitrate is most preferable. Therefore, the molar ratio (A: B: C) of In, Sn (metal A), Ga, Al (metal B), and Zn (metal C) is as described above. It is preferable to form a precursor thin film containing a metal inorganic salt by coating using a coating solution in which nitrate of each metal is dissolved and formed in a solvent containing water as a main component so as to satisfy the formula.

  Moreover, the film thickness of the thin film containing the metal inorganic salt used as a precursor is 1-200 nm, More preferably, it is 5-100 nm.

(Amorphous oxide)
As the metal oxide semiconductor to be formed, any state of single crystal, polycrystal, and amorphous can be used, but an amorphous thin film is preferably used.

The electron carrier concentration of an amorphous oxide, which is a metal oxide according to the present invention, formed from a metal compound material that is a precursor of a metal oxide semiconductor only needs to be less than 10 ¹⁸ / cm ³ . The electron carrier concentration is a value when measured at room temperature. The room temperature is, for example, 25 ° C., specifically, a certain temperature appropriately selected from the range of about 0 ° C. to 40 ° C. Note that the electron carrier concentration of the amorphous oxide according to the present invention does not need to satisfy less than 10 ¹⁸ / cm ³ in the entire range of 0 ° C. to 40 ° C. For example, a carrier electron density of less than 10 ¹⁸ / cm ³ may be realized at 25 ° C. Further, when the electron carrier concentration is further reduced to 10 ¹⁷ / cm ³ or less, more preferably 10 ¹⁶ / cm ³ or less, a normally-off TFT can be obtained with a high yield.

  The electron carrier concentration can be measured by Hall effect measurement.

  The film thickness of the semiconductor that is a metal oxide is not particularly limited, but the characteristics of the obtained transistor are often greatly influenced by the film thickness of the semiconductor film, and the film thickness varies depending on the semiconductor. Generally, 1 μm or less, particularly 10 to 300 nm is preferable.

In the present invention, the precursor material (metal salt), composition ratio, production conditions, and the like are controlled so that, for example, the electron carrier concentration is 10 ¹² / cm ³ or more and less than 10 ¹⁸ / cm ³ . More preferably, it is in the range of 10 ¹³ / cm ³ or more and 10 ¹⁷ / cm ³ or less, and more preferably 10 ¹⁵ / cm ³ or more and 10 ¹⁶ / cm ³ or less.

  Examples of the semiconductor conversion treatment, that is, a method of converting a precursor thin film formed from a metal inorganic salt into a metal oxide semiconductor include oxidation treatments such as an oxygen plasma method, a thermal oxidation method, and a UV ozone method. Further, the above microwave irradiation can be used.

  As thermal oxidation, heat treatment is preferably performed in the presence of oxygen in a temperature range of 100 ° C. to 400 ° C. By using a metal salt such as nitrate, sulfate, phosphate, carbonate, acetate or oxalate which is a semiconductor precursor, the semiconductor conversion treatment can be performed at a relatively low temperature.

  Further, formation of the metal oxide by the conversion treatment can be detected by ESCA or the like, and conditions under which the conversion to the semiconductor is sufficiently performed can be selected in advance.

  Further, it is preferable to use an atmospheric pressure plasma method as the oxygen plasma method. In the oxygen plasma method and the UV ozone method, the substrate is preferably heated in the range of 50 ° C to 300 ° C.

  In the atmospheric pressure plasma method, an inert gas such as argon gas is used as a discharge gas under atmospheric pressure, and a reaction gas (a gas containing oxygen) is introduced into the discharge space, and a high frequency electric field is applied to the discharge gas. Is excited to generate plasma, and contact with a reactive gas to generate plasma containing oxygen, and the substrate surface is exposed to this to perform oxygen plasma treatment. Under atmospheric pressure represents a pressure of 20 to 110 kPa, preferably 93 to 104 kPa.

  Using an atmospheric pressure plasma method, oxygen plasma is generated as a reactive gas, oxygen plasma is generated, and the precursor thin film containing a metal salt is exposed to the plasma space, so that the precursor thin film is oxidized and decomposed by plasma oxidation. A layer made of a metal oxide is formed.

The high frequency power source is 0.5 kHz or more and 2.45 GHz or less, and the power supplied between the counter electrodes is preferably 0.1 W / cm ² or more and 50 W / cm ² or less.

  The gas used is basically a mixed gas of a discharge gas (inert gas) and a reaction gas (oxidizing gas). The reaction gas is preferably oxygen gas and is preferably contained in an amount of 0.01 to 10% by volume with respect to the mixed gas. Although it is more preferable that it is 0.1-10 volume%, More preferably, it is 0.1-5 volume%.

  Examples of the inert gas include Group 18 elements of the periodic table, specifically, helium, neon, argon, krypton, xenon, radon, nitrogen gas, and the like, in order to obtain the effects described in the present invention. For this, helium, argon, or nitrogen gas is preferably used.

  In order to introduce the reaction gas between the electrodes which are the discharge space, normal temperature and normal pressure may be used.

  The plasma method under atmospheric pressure is described in JP-A Nos. 11-61406, 11-133205, 2000-121804, 2000-147209, 2000-185362, and the like.

  The UV ozone method is a method in which an ultraviolet light is irradiated in the presence of oxygen to advance an oxidation reaction. It is preferable to irradiate so-called vacuum ultraviolet light having a wavelength of ultraviolet light of 100 nm to 450 nm, particularly preferably about 150 to 300 nm. As the light source, a low-pressure mercury lamp, a deuterium lamp, a xenon excimer lamp, a metal halide lamp, an excimer laser, or the like can be used.

The output of the lamp ^{400W~30kW, 100mW / cm 2 ~100kW /} cm 2 as illuminance, preferably 10~5000mJ / cm ² as irradiation energy, 100 to 2000 mJ / cm ² is more preferable.

The illuminance at the time of ultraviolet irradiation is preferably 1 mW to 10 W / cm ² .

  In the present invention, it is preferable to perform a heat treatment after the oxidation treatment or simultaneously with the oxidation treatment in addition to the oxidation treatment. Thereby, oxidative decomposition can be promoted.

  Moreover, after oxidizing the thin film containing a metal salt, the substrate may be heated in the range of 50 ° C. to 200 ° C., preferably in the range of 80 ° C. to 150 ° C., and the heating time in the range of 1 minute to 10 hours. preferable.

  The heat treatment may be performed at the same time as the oxidation treatment, and can be quickly converted into a metal oxide semiconductor by oxidation.

  After the conversion to a metal oxide semiconductor, the thickness of the formed semiconductor thin film is preferably 1 to 200 nm, more preferably 5 to 100 nm.

  In the present invention, as the semiconductor conversion treatment, it is preferable to use microwave (0.5 to 50 GHz) irradiation in the presence of oxygen as described above.

  When microwave irradiation is used, a semiconductor conversion process can be performed by selectively allowing an oxidation reaction to proceed in a short time in the semiconductor precursor layer containing the metal salt.

  Further, other elements constituting the thin film transistor will be described below.

(electrode)
In the present invention, the conductive material used for the electrodes such as the source electrode, the drain electrode, and the gate electrode constituting the thin film transistor element is not particularly limited as long as it has conductivity at a practical level as an electrode. Gold, silver, nickel, chromium, copper, iron, tin, antimony lead, tantalum, indium, palladium, tellurium, rhenium, iridium, aluminum, ruthenium, germanium, molybdenum, tungsten, and also, for example, antimony tin oxide, oxide Electrode materials with electromagnetic wave absorption ability such as indium tin (ITO), fluorine-doped zinc oxide, zinc, carbon, graphite, glassy carbon, silver paste and carbon paste, lithium, beryllium, sodium, magnesium, potassium, calcium, scandium, titanium Manganese, zirconium, gallium, niobium, sodium, sodium-potassium alloy, magnesium, lithium, aluminum, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide mixture, lithium / aluminum A mixture or the like is used.

  Moreover, a conductive polymer, metal microparticles, etc. can be used suitably as a conductive material.

  As a dispersion containing metal fine particles, for example, a known conductive paste may be used, but a dispersion containing metal fine particles having a particle diameter of 1 nm to 50 nm, preferably 1 nm to 10 nm is preferable. In order to form an electrode from metal fine particles, the above-described method can be used in the same manner, and the metal described above can be used as the material of the metal fine particles.

(Method for forming electrodes, etc.)
As a method of forming an electrode, when the method of the present invention is not used, the above is used as a raw material, a method of forming using a method such as vapor deposition or sputtering through a mask, or a conductivity formed by a method such as vapor deposition or sputtering. There are a method of forming an electrode using a known photolithography method and a lift-off method, and a method of forming a resist on a metal foil such as aluminum or copper by thermal transfer, ink jet or the like and etching. Alternatively, a conductive polymer solution or dispersion, a dispersion containing metal fine particles, or the like may be directly patterned by an ink jet method, or may be formed from a coating film by lithography or laser ablation. Further, a method of patterning a conductive ink or conductive paste containing a conductive polymer or metal fine particles by a printing method such as relief printing, intaglio printing, planographic printing, or screen printing can also be used.

  Further, as a method for forming a source, drain electrode, etc., and a gate bus line, a source bus line, etc. without patterning a metal thin film using a photosensitive resin such as etching or lift-off, a method by an electroless plating method is known. ing.

  Regarding the method of forming an electrode by electroless plating, as described in Japanese Patent Application Laid-Open No. 2004-158805, a liquid containing a plating catalyst that causes electroless plating by acting with a plating agent on a portion where an electrode is provided After patterning, for example, by a printing method (including inkjet printing), a plating agent is brought into contact with a portion where an electrode is provided. If it does so, electroless plating will be performed by the contact of the said catalyst and a plating agent, and an electrode pattern will be formed.

  The application of the electroless plating catalyst and the plating agent may be reversed, and the pattern formation may be performed either way, but a method of forming a plating catalyst pattern and applying the plating agent to this is preferable.

  As the printing method, for example, screen printing, planographic printing, letterpress printing, intaglio printing, printing by ink jet printing, or the like is used.

(Gate insulation film)
Various insulating films can be used as a gate insulating film of the thin film transistor. In particular, an inorganic oxide film having a high relative dielectric constant is preferable. Inorganic oxides include silicon oxide, aluminum oxide, tantalum oxide, titanium oxide, tin oxide, vanadium oxide, barium strontium titanate, barium zirconate titanate, lead zirconate titanate, lead lanthanum titanate, strontium titanate, Examples thereof include barium titanate, barium magnesium fluoride, bismuth titanate, strontium bismuth titanate, strontium bismuth tantalate, bismuth tantalate niobate, and yttrium trioxide. Of these, silicon oxide, aluminum oxide, tantalum oxide, and titanium oxide are preferable. Inorganic nitrides such as silicon nitride and aluminum nitride can also be suitably used.

  Examples of the method for forming the film include a vacuum process, a molecular beam epitaxial growth method, an ion cluster beam method, a low energy ion beam method, an ion plating method, a CVD method, a sputtering method, an atmospheric pressure plasma method, and a spray process. Examples include wet processes such as coating methods, spin coating methods, blade coating methods, dip coating methods, casting methods, roll coating methods, bar coating methods, die coating methods, and other methods such as printing and ink jet patterning. Can be used depending on the material.

  The wet process is a method of applying and drying a liquid in which fine particles of inorganic oxide are dispersed in an arbitrary organic solvent or water using a dispersion aid such as a surfactant as required, or an oxide precursor, for example, A so-called sol-gel method in which a solution of an alkoxide body is applied and dried is used.

  Among these, the atmospheric pressure plasma method is preferable.

  It is also preferable that the gate insulating film (layer) is composed of an anodized film or the anodized film and an insulating film. The anodized film is preferably sealed. The anodized film is formed by anodizing a metal that can be anodized by a known method.

  Examples of the metal that can be anodized include aluminum and tantalum, and the anodizing method is not particularly limited, and a known method can be used.

  Examples of organic compound films include polyimides, polyamides, polyesters, polyacrylates, photo-radical polymerization-type, photo-cationic polymerization-type photo-curable resins, copolymers containing acrylonitrile components, polyvinyl phenol, polyvinyl alcohol, novolac resins, etc. Can also be used.

  An inorganic oxide film and an organic oxide film can be laminated and used together. The thickness of these insulating films is generally 50 nm to 3 μm, preferably 100 nm to 1 μm.

[Protective layer]
It is also possible to provide a protective layer on the organic thin film transistor element. Examples of the protective layer include inorganic oxides or inorganic nitrides, metal thin films such as aluminum, polymer films with low gas permeability, and laminates thereof. By having such a protective layer, the durability of the organic thin film transistor is achieved. Will improve. As a method for forming these protective layers, the same method as the method for forming the gate insulating film described above can be used. Further, the protective layer may be provided by a method such as simply laminating a film in which various inorganic oxides are laminated on the polymer film.

(substrate)
Various materials can be used as the support material constituting the substrate. For example, ceramic substrates such as glass, quartz, aluminum oxide, sapphire, silicon nitride, silicon carbide, silicon, germanium, gallium arsenide, gallium phosphide. In addition, a semiconductor substrate such as gallium nitrogen, paper, and non-woven fabric can be used. In the present invention, the support (substrate) is preferably made of a resin, for example, a plastic film sheet can be used. Examples of plastic films include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide (PPS), polyarylate, polyimide (PI), and polyamide. Examples thereof include films made of imide (PAI), polycarbonate (PC), cellulose triacetate (TAC), cellulose acetate propionate (CAP), and the like.

  The conductive thin film of the present invention can be preferably used as an electrode of an organic electroluminescence (EL) element.

  Hereinafter, the organic EL element will be described.

  FIG. 4 is a schematic cross-sectional view showing an example of the layer configuration of the organic EL element. FIG. 4 is a schematic cross-sectional view showing a constituent layer of an organic EL element having a sealing film attached thereto.

  The layer structure of the organic EL element shown in FIG. 4 will be described.

  In the figure, 1b represents an organic EL element. The organic EL element 1b includes a first electrode 2, a hole transport layer 3, a light emitting layer 4, an electron injection layer 5, a second electrode 6, an adhesive layer 8, and a sealing material on a substrate 1. The film 9 is provided in this order. In the organic EL element shown in the figure, a hole injection layer (not shown) may be provided between the first electrode 2 and the hole transport layer 3. Further, an electron transport layer (not shown) may be provided between the light emitting layer 4 and the electron injection layer 5. In the organic EL element 1b shown in this figure, a gas barrier film (not shown) may be provided between the first electrode 2 and the substrate 1.

  A conductive thin film such as ITO formed by the electrode manufacturing method according to the present invention can be preferably used as the anode of the organic EL element shown in FIG. Since it can be formed by coating, it can be easily formed as compared with a manufacturing method that requires a large-scale apparatus such as sputtering.

  In addition to the above-described layer configuration, the organic EL device includes the following configuration as a typical layer configuration example.

(1) Base material / anode / light emitting layer / electron transport layer / cathode / sealing layer (2) Base material / anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode / sealing layer (3) substrate / anode / hole transport layer (hole injection layer) / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer (electron injection layer) / cathode / sealing layer (4) substrate / Anode / anode buffer layer (hole injection layer) / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer (electron injection layer) / cathode / sealing layer sandwiched between two electrodes By applying an electric field to the organic functional layer, carriers are injected, and light emission is extracted by recombination of carriers in the light emitting layer. In order to efficiently move the carrier layer or between the layers, the functional layers are arranged in a predetermined order between the two electrodes of the anode (first electrode) and the cathode (second electrode).

  Next, the material used in each of these organic functional layers constituting the organic EL element will be described.

  Among the organic functional layers, organic light emitting materials contained in the light emitting layer include aromatic heterocyclic compounds such as carbazole, carboline, diazacarbazole, triarylamine derivatives, stilbene derivatives, polyarylenes, aromatic condensed polycycles. Examples thereof include compounds, aromatic heterofused ring compounds, metal complex compounds, and the like, and single oligo compounds or composite oligo compounds thereof, but the present invention is not limited to this, and widely known materials can be used. .

  The layer (film forming material) may preferably contain about 0.1 to 20% by mass of a dopant in the light emitting material. Examples of the dopant include known fluorescent dyes such as perylene derivatives and pyrene derivatives, and in the case of phosphorescent light emitting layers, for example, tris (2-phenylpyridine) iridium, bis (2-phenylpyridine) (acetylacetonate). A complex compound such as an orthometalated iridium complex represented by iridium, bis (2,4-difluorophenylpyridine) (picolinato) iridium, and the like is similarly contained in an amount of about 0.1 to 20% by mass. The thickness of these light emitting layers ranges from 1 nm to several hundred nm.

  Examples of materials used in the hole injection / transport layer include phthalocyanine derivatives, heterocyclic azoles, aromatic tertiary amines, polyvinyl carbazole, polyethylene dioxythiophene / polystyrene sulfonic acid (PEDOT: PSS), and the like. Polymer materials such as conductive polymers are also used for the light emitting layer, for example, carbazole-based light emitting materials such as 4,4′-dicarbazolylbiphenyl, 1,3-dicarbazolylbenzene, (di ) Low molecular light emitting materials represented by pyrene-based light emitting materials such as azacarbazoles, 1,3,5-tripyrenylbenzene, polymer light emitting materials represented by polyphenylene vinylenes, polyfluorenes, polyvinyl carbazoles, etc. Etc.

  Examples of the electron injection / transport layer material include metal complex compounds such as 8-hydroxyquinolinate lithium and bis (8-hydroxyquinolinate) zinc, and nitrogen-containing five-membered ring derivatives listed below. That is, oxazole, thiazole, oxadiazole, thiadiazole or triazole derivatives are preferred. Specifically, 2,5-bis (1-phenyl) -1,3,4-oxazole, 2,5-bis (1-phenyl) -1,3,4-thiazole, 2,5-bis (1 -Phenyl) -1,3,4-oxadiazole, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) 1,3,4-oxadiazole, 2,5-bis ( 1-naphthyl) -1,3,4-oxadiazole, 1,4-bis [2- (5-phenyloxadiazolyl)] benzene, 1,4-bis [2- (5-phenyloxadiazolyl) -4-tert-butylbenzene], 2- (4'-tert-butylphenyl) -5- (4 "-biphenyl) -1,3,4-thiadiazole, 2,5-bis (1-naphthyl) -1 , 3,4-thiadiazole, 1,4-bis [2- (5-phenyl) Asiazolyl)] benzene, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-triazole, 2,5-bis (1-naphthyl) -1,3,4 -Triazole, 1,4-bis [2- (5-phenyltriazolyl)] benzene and the like.

  The film thickness of the organic EL element and each organic layer is required to be about 0.05 to 0.3 μm, and preferably about 0.1 to 0.2 μm.

  Moreover, as a formation method of each organic functional layer (organic EL each functional layer), various film-forming methods, such as a vapor deposition method and a sputtering method, can be used, Application | coating and printing etc. which are wet processes are preferable. For example, die coat method, screen printing method, flexographic printing method, ink jet method, wire bar method, cap coating method, spray coating method, casting method, roll coating method, bar coating method, gravure coating method, etc. can be used. It is. The use of these wet coating machines can be appropriately selected according to the material of the organic compound layer.

  Each organic material has its own solubility characteristics (solubility parameters, ionization potential, polarity), and there are limitations on the solvents that can be dissolved. In this case, since the solubility is different, the concentration cannot be generally determined. However, the type of the solvent used in the present invention is suitable for the above conditions depending on the organic EL material to be formed. Can be selected from known solvents, for example, halogenated hydrocarbon solvents such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride, tetrachloroethane, trichloroethane, chlorobenzene, and ether solvents such as dibutyl ether, tetrahydrofuran, and dioxane. , Methanol, ethanol, isopropanol, cyclohexanol, 2-methoxyethanol, ethylene glycol, glycerol and other alcohol solvents, benzene, toluene, xylene, ethylbenzene and other aromatic hydrocarbon solvents, hexane, octane, tetraly Paraffin solvents such as ethyl acetate, ester solvents such as ethyl acetate and butyl acetate, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methylpyrrolidone, and ketones such as acetone, methyl ethyl ketone and cyclohexanone Examples of the solvent include amine solvents such as pyridine and aniline, nitrile solvents such as acetonitrile and valeronitrile, and sulfur solvents such as thiophene and carbon disulfide.

  In addition, the solvent which can be used is not restricted to these, You may mix and use 2 or more types of these as a solvent.

  Among these, preferred examples of the organic EL material vary depending on the material of the functional layer. However, as the good solvent, for example, an aromatic solvent, a halogen solvent, an ether solvent, and the like are preferable. Family solvents and ether solvents. Examples of the poor solvent include alcohol solvents, ketone solvents, paraffin solvents, and the like. Among them, alcohol solvents and paraffin solvents are used.

  In the present invention, an organic compound having a reactive group (reactive organic compound) may be used in each functional layer. There is no restriction | limiting in particular as a layer using a reactive organic compound, It can use for each layer. An organic material having a function having a reactive group in each functional layer may be used.

  After forming the reactive organic compound coating layer, it is allowed to react on the substrate to form a network polymer of organic molecules, which can be cured. Generation | occurrence | production of a network polymer can suppress element deterioration by Tg (glass transition point) adjustment of a structure layer.

  On the other hand, on the manufacturing side, for example, in the case of a step of laminating by coating, it is preferable that the lower layer does not dissolve in the upper layer coating solution. Therefore, the upper layer can be applied by resinating the lower layer and degrading solvent solubility. be able to. For example, when the hole transport layer is resinized as an organic layer thus crosslinked, dissolution and penetration of the lower layer can be prevented when the light emitting layer is applied as the upper layer.

  Although it does not specifically limit as a reactive group which can be used, For example, a vinyl group, an ethynyl group, an isocyanate group, an epoxy group etc. are mentioned typically.

  Of the two electrodes, a conductive material used for the anode for injecting holes as the first electrode is suitable to have a work function larger than 4 eV, and is silver, gold, platinum, palladium. And their alloys, metal oxides such as tin oxide, indium oxide and ITO, and organic conductive resins such as polythiophene and polypyrrole. It is preferable to be translucent, and using a conductive thin film such as an ITO film prepared by the method of the present invention as these anodes can form a highly conductive transparent film by coating, preferable.

  As the conductive material used as the cathode as the second electrode, those having a work function smaller than 4 eV are suitable, such as magnesium and aluminum. Typical examples of the alloy include magnesium / silver and lithium / aluminum. The formation method can be mask vapor deposition, photolithography patterning, plating, printing, or the like, but is not limited thereto.

  As the support used for the organic EL device, the same glass, ceramic or transparent resin film as described above is used.

  When using a resin film, it is preferable to use a gas barrier film in which a gas barrier layer is formed on these supports. Examples of the gas barrier layer include a thin film having a low moisture permeability made of a material having a low moisture permeability such as silicon oxide, silicon nitride, silicon oxynitride having a thickness of several nanometers to several hundred nanometers.

  It is also preferable to cover and bond and seal with a sealing film. The sealing film is preferably a gas barrier resin film having a low moisture permeability. These films have a transparent thickness of several nanometers to several hundred nanometers on the film mentioned as the flexible support such as polyester such as polyethylene terephthalate, polycarbonate, polyethylene, ethylene-vinyl alcohol copolymer, and polypropylene. Examples thereof include a film in which a thin film made of a material having low moisture permeability such as silicon oxide, silicon nitride, and silicon oxynitride is formed, and a film in which an alumina vapor deposition film or the like that is a gas barrier film is formed. For example, a metal vapor-deposited film such as Toppan Printing, GX film, silica vapor-deposited film such as Tech Barrier (Mitsubishi Resin), or the above-mentioned film on which a gas barrier layer such as an alumina vapor-deposited film is formed can be used.

  As an adhesive used for sealing, a UV curable adhesive composition made of an acrylic resin, an epoxy resin, a fluorine resin, or the like can be used. For example, a UV resin XNR5516 manufactured by Nagase Chemtech Co., Ltd. UV curable adhesive (resin) can be used. Of course, a heat bonding resin may be used.

  The conductive thin film of the present invention will be specifically described below with reference to examples.

[Comparative Example 1]
7.5 g of ITO powder (BET particle size 30 nm) containing 15% by mass of SnO ₂ as transparent conductive particles was mixed with 17.5 g of an alcohol solvent and 0.225 g of an anionic surfactant, and a planetary ball mill (Fritche) was mixed. A P-5 type, a container capacity of 80 ml, and a bead PSZ of 0.3 mm) were rotated at 300 rpm for 30 minutes to prepare a dispersion as a fluid material. The ITO dispersion liquid having an ITO content of 30% by mass obtained in this manner was applied to an PET film (Toray Lumirror 100T haze 1.5% total light transmittance 89% as a substrate) using an applicator (feed rate 5 m / min). ) And dried at a temperature of 80 ° C. Thereafter, this PET film was pressed at a linear pressure of 200 kg / cm using a roll press (film feed rate of 2.5 m / min), and the density of the coating film on the PET film was adjusted to 3.0 g / cm ³ . Thereafter, the transparent conductive film was irradiated with microwaves having a frequency of 2.45 GHz at 1000 W for 10 minutes in a nitrogen atmosphere.

  Table 1 shows the surface resistance, total light transmittance, and haze of the transparent conductive film obtained by the above procedure.

[Comparative Example 2]
Comparative Example 2 was produced in the same procedure as Comparative Example 1 except that the linear pressure of the roll press was 300 kg / cm.

[Comparative Example 3]
In Comparative Example 3, a dispersion prepared in the same manner as in Comparative Example 1 was applied on a substrate with an applicator, dried at 80 ° C., and then irradiated with microwaves at 1000 W for 10 minutes without applying a roll press. Manufactured.

[Example 1]
7.5 g of ITO powder (BET particle size 30 nm) containing 15% by mass of SnO ₂ as transparent conductive particles, 0.12 g of tin nitrate, 0.63 g of indium nitrate, 17.5 g of alcohol solvent and anionic surface activity The mixture was mixed with 0.225 g of the agent, and rotated at 300 rpm for 30 minutes in a planetary ball mill (Fritche P-5 type, container capacity 80 ml, beads PSZ 0.3 mm) to prepare a dispersion as a fluid material. The ITO dispersion liquid having an ITO content of 30% by mass obtained in this manner was applied to an PET film (Toray Lumirror 100T haze 1.5% total light transmittance 89% as a substrate) using an applicator (feed rate 5 m / min). ) And dried at a temperature of 80 ° C. Thereafter, the transparent conductive film was irradiated with microwaves having a frequency of 2.45 GHz at 1000 W for 10 minutes in a nitrogen atmosphere.

[Example 2]
Example 2 was produced in the same procedure as Example 1 except that the time of microwave irradiation was 5 minutes.

[Example 3]
Example 3 was manufactured in the same procedure as Example 1 except that microwave irradiation was performed at 500W.

[Example 4]
Example 4 was produced in the same procedure as Example 1 except that the amount of tin nitrate and indium nitrate added was changed to 0.06 g of tin nitrate and 0.31 g of indium nitrate.

[Example 5]
The same procedure as in Example 1 was performed except that the added tin nitrate and indium nitrate were replaced with 0.6 g of zinc nitrate and 0.06 g of aluminum nitrate. A dispersion prepared in the same manner as in Example 1 was applied onto a substrate with an applicator, dried at 80 ° C., and then irradiated with microwaves at 1000 W for 10 minutes for production.

  The surface resistance, total light transmittance, and haze of the conductive thin film were measured by the following methods.

<BET particle size>
The BET particle size of the transparent conductive fine particles of the transparent conductive film (coating film) was calculated by the following formula.

BET particle size (nm) = 6 / (ρ × specific surface area) × 10 ⁹
However, ρ is the true specific gravity of the transparent conductive fine particles. For example, when the transparent conductive fine particles are ITO (tin-containing indium oxide), ρ = 7.13 × 10 ⁹ (g / m ³ ). . The specific surface area was determined by the BET method (one point method).

<Surface resistance>
The surface resistance of the conductive thin film was measured by a four-probe method using Loresta HP manufactured by Mitsubishi Chemical Corporation.

<Total light transmittance and haze>
The light transmittance and haze of the conductive thin film were measured using NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd. A halogen lamp was used as the light source.

  In addition, about the film thickness used for calculating the density of the coating film, it was observed and measured at a magnification of 10,000 times using a JSM-6700F scanning electron microscope manufactured by JEOL Ltd. The film density was as follows. Measured according to the procedure.

That is, a PET film serving as a substrate is cut in advance to 5 (cm) × 5 (cm) and the mass is measured. Next, the substrate (the “substrate coated with the coating film” in the following formula) that has been dried and pressed after application of the conductive fine particles is cut into 5 (cm) × 5 (cm), and the mass is measured. Subsequently, the film thickness of the coating film was measured using a scanning electron microscope, and the density of the film was determined from the following formula based on the mass and the film thickness obtained by the measurement. Note that the substrate thickness after the roll press is not changed, and the substrate mass is not changed.
(Membrane density) = {(Substrate mass coated film) − (Substrate mass)} / {(Coating film area) × (Coating film thickness)}
Table 1 below shows the surface resistance, total light transmittance, and haze of the conductive thin films prepared in Comparative Examples 1-3 and Examples 1-4.

  It can be seen that the conductive thin film according to the present invention is superior in both conductivity and transparency due to the presence of a metal oxide precursor during firing, compared to a conductive thin film manufactured using a conventionally known manufacturing method. .

[Comparative Example 4]
An aqueous dispersion containing ITO fine particles (Cii Kasei Nanotech, fine particle diameter of 10 to 100 nm, solid content concentration of 15%) is applied onto a glass substrate, and pressed with a roll press (linear pressure 200 kg / cm), then 2.45 GHz. Were irradiated at 500 W for 30 minutes.

  The resulting film had a center line average roughness Ra of 20 nm and a surface resistance of 100 (Ω / □).

  Using the transparent conductive film thus prepared as a gate electrode, a polysilazane solution (Aquamica NN110-20) was spin-coated at 1000 rpm on the upper layer, and then heated at 450 ° C. to form a gate insulating film.

  Next, an aqueous solution of 1: 1: 1 each of indium nitrate, gallium nitrate, and zinc nitrate is applied by patterning to the insulating film by an ink jet method, and then irradiated with an electromagnetic wave of 2.45 GHz at 500 W for 10 minutes in the atmosphere. A film was formed.

Next, silver nanoparticle ink was patterned and heated at both ends of the IGZO film to form a source electrode and a drain electrode so as to have a channel length of 20 μm and a channel width of 60 μm. When the Id-Vg characteristics of the TFT thus prepared were measured, the off current was 10 nA and the mobility was 0.05 cm ² / Vs.

[Example 6]
An aqueous dispersion containing ITO fine particles (diluted and redispersed with C-I Kasei Nanotech as a raw material to adjust the fine particle diameter to 10 to 100 nm and a solid content concentration of 3%), and indium nitrate and tin nitrate are each 5% by mass with respect to water. A coating solution dissolved so as to be prepared was prepared. This coating solution was applied onto glass and irradiated with an electromagnetic wave of 2.45 GHz at 500 W for 30 minutes. The resulting transparent conductive film had a center line average roughness Ra of 1 nm and a surface resistance of 100 (Ω / □).

  Using the transparent conductive film thus prepared as a gate electrode, similarly to Comparative Example 4, a gate insulating film, a semiconductor film, a source, and a drain electrode were sequentially formed to form a thin film transistor.

When the Id-Vg characteristic of this TFT was measured, the off current was 10 pA, and the mobility was 0.1 cm ² / Vs. A thin film transistor element having a lower off current, higher mobility, and higher on / off ratio than the element of Comparative Example 4 was obtained.

[Example 7]
<< Organic EL element >>
A transparent gas barrier layer and an anode were formed by a method described below using a polyethylene naphthalate film having a thickness of 100 μm (a film made by Teijin DuPont, hereinafter abbreviated as PEN).

<Formation of transparent gas barrier layer>
On the prepared PEN, a transparent gas barrier layer having a thickness of about 90 nm was formed using tetraethoxysilane (reactive gas) using an atmospheric pressure plasma discharge treatment method. As a result of measuring the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2% RH)) by a method according to JIS K-7129-1992, it was 10 ⁻³ g / (m ² · 24 h) or less. there were. Moreover, as a result of measuring oxygen permeability by the method based on JIS K-7126-1987, it was below 10 < ^-3 > cm < ³ > / (m < ² > 24h * atm).

<Formation of anode>
On the formed transparent gas barrier layer, ITO (indium tin oxide) having a thickness of 120 nm was prepared in the same manner as in Example 5.

<Formation of organic functional layer>
On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. After forming the film by spin coating, the film was dried at 200 ° C. for 1 hour to provide a 20 nm-thick hole transport layer.

  This substrate was transferred to a nitrogen atmosphere, and a solution of 50 mg of the hole transport material 1 dissolved in 10 ml of toluene was formed on the hole transport layer by spin coating at 1500 rpm for 30 seconds. In a nitrogen atmosphere, ultraviolet light was irradiated for 180 seconds to carry out photopolymerization and crosslinking to form a second hole transport layer having a thickness of about 20 nm.

  On this second hole transport layer, a solution prepared by dissolving 100 mg of compound 2 and 10 mg of compound 3 in 10 ml of toluene was formed into a film by a spin coating method at 1000 rpm for 30 seconds. It vacuum-dried at 120 degreeC for 1 hour, and was set as the light emitting layer with a film thickness of about 50 nm.

  Next, a solution obtained by dissolving 50 mg of the electron transport material 1 in 10 ml of 1-butanol was formed on this light emitting layer by spin coating under a condition of 5000 rpm for 30 seconds. It vacuum-dried at 60 degreeC for 1 hour, and was set as the electron carrying layer with a film thickness of about 15 nm.

Subsequently, this substrate is fixed to a substrate holder of a vacuum deposition apparatus, the vacuum chamber is decompressed to 4 × 10 ⁻⁴ Pa, lithium fluoride 1.0 nm is deposited as a cathode buffer layer, and aluminum 110 nm is deposited as a cathode to form a cathode. Then, an organic EL element was produced.

When a ^2.5 mA / cm ² constant current was applied to the produced organic EL element at 23 ° C. in a dry nitrogen gas atmosphere, light emission was observed from the anode side, and a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) When measured using, high external extraction quantum efficiency was exhibited. The ITO conductive thin film formed by the coating method of the present invention exhibited excellent properties as an anode of an organic EL element.

It is sectional drawing which shows the structural example of a thin-film transistor element. It is an equivalent circuit diagram showing an example of a thin film transistor (TFT) sheet in which a plurality of thin film transistors are arranged. It is a figure explaining one Embodiment of the electroconductive thin film of this invention applied to the gate electrode of a thin-film transistor element. It is a schematic sectional drawing which shows an example of the laminated constitution of an organic EL element.

Explanation of symbols

1 Base material
2 First electrode 3 Hole transport layer 4 Light emitting layer 5 Electron injection layer 6 Second electrode 8 Adhesive layer 9 Sealing film 101 Semiconductor layer 102 Source electrode 103 Drain electrode 104 Gate electrode 105 Insulating layer 10 Thin film transistor sheet 11 Gate bus line 12 Source Bus Line 14 Thin Film Transistor Element 15 Storage Capacitor 16 Output Element 17 Vertical Drive Circuit 18 Horizontal Drive Circuit

Claims (8)

A method for producing an electrode, comprising: forming a thin film containing at least metal oxide fine particles and a metal oxide precursor on a substrate; and irradiating the thin film with electromagnetic waves to form a conductive thin film. The method for producing an electrode according to claim 1, wherein the metal oxide fine particles are oxide fine particles containing any of titanium, copper, nickel, zinc, tin, and indium. The method for producing an electrode according to claim 2, wherein the metal oxide precursor contains zinc, tin, indium inorganic acid salt, halide, or hydroxide. The method for producing an electrode according to claim 2, wherein the metal oxide precursor includes a nitrate of any one of zinc, tin, and indium. The method for producing an electrode according to claim 1, wherein the thin film is formed by coating. The said electromagnetic wave is a microwave (frequency 0.3-30 GHz), The manufacturing method of the electrode of any one of Claims 1-5 characterized by the above-mentioned. A thin film transistor element produced by using an electronic circuit pattern formed by the electrode manufacturing method according to claim 1. An organic electroluminescent element, wherein an anode is formed using the method for producing an electrode according to claim 1.

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