JP5119990B2 - Coating composition for forming high dielectric thin film and method for producing the same - Google Patents

Description

  The present invention relates to a coating composition for forming a high dielectric thin film and a method for producing the same. More specifically, the present invention comprises a perovskite type dielectric material obtained by an organic acid salt pyrolysis method (hereinafter sometimes referred to as MOD method). In the formation of a high dielectric thin film, the improvement in productivity due to the uniformity of the coating film, the handling property by an appropriate drying speed, and the thick film formation by an appropriate viscosity is achieved, and there is no generation of cracks. The present invention relates to a coating composition for forming a high dielectric thin film capable of forming a dielectric thin film having excellent dielectric properties and an efficient manufacturing method thereof.

In recent years, with the miniaturization of capacitor elements and the high integration of semiconductor integrated circuits, capacitor insulating films used for capacitor insulating films of thin film capacitors and semiconductor integrated circuit devices, capacitor materials of DRAMs, etc. have a high dielectric constant. Substances are sought. As such a material having a high dielectric constant, a composite oxide having a perovskite crystal structure is known. For example, barium titanate-based dielectric materials such as barium titanate (BaTiO ₃ ), strontium titanate (SrTiO ₃ ), calcium titanate (CaTiO ₃ ), barium strontium titanate ((Ba, Sr) TiO ₃ ) have attracted attention. ing.

  Further, as a method for forming a thin film of a substance having such a high dielectric constant, a sputtering method, a sol-gel method, a MOD method, a CVD method or the like is performed. However, both the sputtering method and the CVD method have a complicated apparatus and have a drawback that the film formation speed is slow, and the area on which the film can be formed is small, so that a film with a large area can be obtained. There is a problem that it is not possible. On the other hand, in the sol-gel method or the MOD method, a relatively simple process of applying a liquid material containing a compound that forms a perovskite-type composite oxide by thermal decomposition on a substrate and baking the substrate is large in an inexpensive facility. There is an advantage that a thin film having an area can be obtained, and this is a promising method that is industrially excellent in mass productivity.

Conventionally, for example, the following (a) to (c) have been proposed for coating compositions for forming a high dielectric thin film used in coating methods such as sol-gel method and MOD method.
(A) Barium and titanium metal soap is used (for example, refer to Patent Document 1).
(B) A barium carboxylate salt such as barium acetate and a raw material of titanium isopropoxide are dissolved in an organic solvent containing ethylene glycol monomethyl ether and hydrolyzed to obtain a composition for forming a barium titanate thin film (for example, , See Patent Document 2).
(C) Barium strontium carboxylate, strontium carboxylate, and titanium isopropoxide are dissolved in an organic solvent as an ester to form a composition for forming a barium strontium titanate thin film (see, for example, Patent Document 3). .

  However, these proposals have many technical problems and practical problems. For example, in (i), barium and strontium carbonates are not generated during the thermal decomposition of metal soap during firing, but the mass change due to the volatilization of organic components is large, so cracks occur in the formed thin film, There arises a problem that the shrinkage of the material increases. In (b), since a carboxylate is used as a raw material, a high temperature exceeding 800 ° C. is required for crystallization during firing. As a result, deterioration of insulation is unavoidable, and since leakage current is large, it has not been put into practical use. The cause of this deterioration is considered to be that micro cracks or voids are generated in the thin film due to rapid shrinkage of the film due to high-temperature firing or reaction with the base electrode. In (c), by using an ester as the solvent, the mass change due to the volatilization of the organic component is small, and the occurrence of cracks and the shrinkage of the film hardly occur. However, expensive barium carboxylate and strontium carboxylate must be used, when a metal film is used for the base electrode, the wettability is poor and it is difficult to obtain a uniform coating film, and the solvent is only an ester. When it is, there existed problems, such as that the preservability by external air will deteriorate.

As described above, in the coating liquid used for forming a high dielectric thin film made of a perovskite type dielectric material, the storage stability of the liquid, the occurrence of cracks in the formed film, the shrinkage of the film, the uniformity of the coating film, etc. It has been desired to solve the problems, and therefore, an organic solvent has been selected and used on the basis of effectively acting on them.
By the way, these coating liquids tend to dilute the liquid concentration in order to suppress the generation of cracks in the film as much as possible. On the other hand, the high dielectric thin film is formed by dropping a coating solution and then spin-coating in order to improve uniformity. At this time, if the liquid concentration is diluted, the thickness of the coating film obtained at one time is thin, and a coating film of 5 to 6 times is required to obtain a desired film thickness. For this reason, since it takes time to form a film, there has been a problem in productivity. In addition, when the coating solution is applied to an uneven surface such as an oxide substrate, depending on the viscosity, the uniformity of the coating due to the repelling of the solution or the flatness of the film surface due to the occurrence of defects such as holes is reduced. Has occurred. In order to improve these problems, when a highly viscous organic solvent is used as a component of the coating liquid, there is a problem that a needle tip nozzle used in coating is clogged.

That is, in a coating solution used for forming a high dielectric thin film made of a perovskite type dielectric material, the storage stability of the solution, the occurrence of cracks in the formed film, the contraction of the film, the uniformity of the coating film, the flatness of the film surface It was difficult to satisfy all the performance problems such as sex.
From the above situation, solution stability, generation of cracks in the formed film, solution of the shrinkage of the film, etc., as well as uniformity of the coating film, handling properties at an appropriate drying speed, and moderate There has been a demand for a method of producing a coating solution that can improve productivity for thickening due to viscosity. In addition, the said handling property represents the use characteristic at the time of a coating film. Usually, since the substrate used in production is large, if the drying speed is too high, a difference in drying occurs immediately after the start of coating and at the end, resulting in uneven coating.

  For this reason, general high-viscosity agents such as ethylene glycol and carbitol are also added, but this may cause residues after baking of the coating film and cause many voids in the thin film, resulting in a decrease in dielectric constant. To do. In addition, since these solvents are highly miscible with water, the long-term storage stability of the coating solution is deteriorated. Moreover, in order to raise not only a viscosity but adhesiveness, addition of a resin binder is mentioned. For example, polyvinyl butyral is soluble in alcohol, but when it is added to the precursor, it becomes highly viscous or gelled, which causes a problem in storage stability and stability of the liquid. Polyvinylpyrrolidinone has a high water absorption and has a problem in storage stability and stability of the liquid after addition.

JP-A-1-308801 (first page) Japanese Patent Laid-Open No. 1-100024 (first page) JP-A-8-337421 (first page, second page)

  In view of the above-mentioned problems of the prior art, the object of the present invention is to form a high dielectric thin film made of a perovskite type dielectric material by the MOD method. A coating composition for forming a high dielectric thin film capable of forming a dielectric thin film that is capable of forming a dielectric thin film that is excellent in dielectric properties and that is improved in productivity due to thickening due to viscosity, and It is to provide an efficient manufacturing method.

  In order to achieve the above object, the present inventors have conducted extensive research on a coating composition for forming a high dielectric thin film used for forming a high dielectric thin film made of a perovskite dielectric material and a method for producing the same. As a result, in the formation of a high dielectric thin film made of a perovskite type dielectric material by the MOD method, a specific resin component is specified in a precursor solution containing a specific organic acid salt in a specific ratio in a specific mixed solvent. When the coating composition contained at an addition ratio is used, the uniformity of the coating film, the handling property by an appropriate drying speed, and the improvement of the productivity for increasing the film thickness by an appropriate viscosity are achieved, and cracks are not generated. It is possible to form a dielectric thin film having no dielectric properties and excellent dielectric properties, and as a method for producing the coating composition, a specific metal alkoxide is specified in a specific mixed solvent. When the specific resin component is added at a specific addition ratio to the precursor solution contained at a ratio, and then stirred under specific conditions, it is found that the coating composition for forming a high dielectric thin film is obtained. The present invention has been completed.

That is, according to the first invention of the present invention, a resin component that satisfies the following requirement (B) is added to the precursor solution that satisfies the following requirement (A) by 0. There is provided a coating composition for forming a high dielectric thin film , containing 2 to 2% by mass and having a viscosity of 4 to 15 mPa · s at 25 ° C.
(A) The precursor solution is selected from the group consisting of 1-butanol, 1-pentanol, 3methyl-1 butanol, 2methyl-1 butanol, 2-methyl-2-butanol, and 2-methyl-1-propanol. In a mixed solvent consisting of at least one alcohol selected from the group consisting of butyl acetate, propyl acetate, isopentyl acetate and butyl butyrate, and 2-ethylhexanoic acid, barium, strontium, It contains an organic acid salt containing at least one metal element selected from the group consisting of magnesium and calcium and at least one metal element selected from the group consisting of titanium, tin and zirconium, and the metal element concentration is 0 .4 to 1.2 mol / L.
(B) The resin component comprises at least one selected from diethyl maleate, dibutyl maleate, methacrylic acid amide, methyl methacrylate, butyl methacrylate, butyl acrylate, and copolymers thereof.

According to the second invention of the present invention, in the first invention, when used as a coating solution, it is applied once on a silicon substrate on which a platinum film is formed on an intermediate film made of oxide, and then spinned. Coating for forming a high dielectric thin film, characterized in that the thickness of the high dielectric thin film obtained by coating with a coating at a rotation of 1500 rpm for 20 seconds and then firing at a temperature of 800 ° C. is 120 to 350 nm. A composition is provided.

Further, according to the third invention of the present invention, in the first invention, when used as a coating solution, it is formed by spin coating on a silicon substrate in which a platinum film is formed on an oxide intermediate film, and thereafter A coating composition for forming a high dielectric thin film, wherein the relative dielectric constant is 600 or more when the thickness of the high dielectric thin film obtained by baking at a temperature of 800 ° C. is 200 to 300 nm. Is provided.

Further, according to the fourth invention of the present invention, a resin component that satisfies the following requirement (b) is added to the precursor solution that satisfies the following requirement (a) by 0.2% with respect to the precursor solution. The coating composition for forming a high dielectric thin film according to any one of the first to third aspects, wherein the coating composition is added at ˜2% by mass and then stirred at a temperature of 100 ° C. to 130 ° C. in air or an inert gas atmosphere. A method of manufacturing an article is provided.
(A) The precursor solution is from the group consisting of 1-butanol, 1-pentanol, 3methyl-1 butanol, 2methyl-1 butanol, 2-methyl-2-butanol, and 2-methyl-1-propanol. In a mixed solvent consisting of at least one alcohol selected from the group consisting of butyl acetate, propyl acetate, isopentyl acetate and butyl butyrate, and 2-ethylhexanoic acid, barium, strontium, It contains an organic acid salt containing at least one metal element selected from the group consisting of magnesium and calcium and at least one metal element selected from the group consisting of titanium, tin and zirconium, and the metal element concentration is 0 .4 to 1.2 mol / L.
(B) The resin component is composed of at least one selected from diethyl maleate, dibutyl maleate, methacrylamide, methyl methacrylate, butyl methacrylate, butyl acrylate, and copolymers thereof.

According to a fifth aspect of the present invention, in the fourth aspect , the resin component may be added by changing the resin component to 1-butanol, 1-pentanol, 3methyl-1-butanol, or 2methyl-1. Performed with a solution of a resin component dissolved in at least one solvent selected from the group consisting of butanol, 2-methyl-2-butanol, 2-methyl-1-propanol, butyl acetate, propyl acetate, isopentyl acetate and butyl butyrate A method of producing a coating composition for forming a high dielectric thin film is provided.

According to a sixth aspect of the present invention, in the fourth aspect , the precursor solution is obtained by a manufacturing method including the following steps (1) to (3): A method for producing a coating composition for film formation is provided.
Step (1): at least one selected from the group consisting of 1-butanol, 1-pentanol, 3methyl-1-butanol, 2methyl-1-butanol, 2-methyl-2-butanol, and 2-methyl-1-propanol At least one ester selected from the group consisting of various alcohols, butyl acetate, propyl acetate, isopentyl acetate and butyl butyrate, and a mixed solvent consisting of 2-ethylhexanoic acid are mixed, and 100 under an inert gas atmosphere. While refluxing at a temperature of ˜110 ° C., a metal of at least one alkaline earth metal element selected from the group consisting of barium, strontium, magnesium and calcium, an alkoxide or a carboxylate thereof, is added, stirred, and metal An organic acid salt solution (A) having an element concentration of 0.4 to 1.2 mol / L is prepared.
Step (2): An alkoxide of at least one element selected from the group consisting of titanium, tin and zirconium is converted into 1-butanol, 1-pentanol, 3methyl-1-butanol, 2methyl-1butanol, 2-methyl- At least one alcohol selected from the group consisting of 2-butanol and 2-methyl-1-propanol, or at least one ester selected from the group consisting of butyl acetate, propyl acetate, isopentyl acetate and butyl butyrate It adds in the solvent which consists of one, and stirs at the temperature of 20-60 degreeC under air | atmosphere, and prepares the alkoxide liquid (B) whose metal element density | concentration is 0.4-1.2 mol / L.
Step (3): The organic acid salt solution (A) and the alkoxide solution (B) are cooled, and then both are combined with the total amount of metal elements contained in the former and the total amount of metal elements contained in the latter. Are mixed at a blending ratio such that and are equal in molar ratio, and then stirred at a temperature of 100 to 110 ° C. in an inert gas atmosphere to synthesize a precursor solution.

According to the seventh invention of the present invention, in the sixth invention, the mixing ratio of the mixed solvent used in the step (1) is 50 to 200 parts by volume of the ester with respect to 100 parts by volume of the alcohol. A method for producing a coating composition for forming a high dielectric thin film is provided, wherein 2-ethylhexanoic acid is 50 to 100 parts by volume.

  The coating composition for forming a high dielectric thin film according to the present invention and a method for producing the same are as follows. In the formation of a high dielectric thin film composed of a perovskite type dielectric material by the MOD method, the uniformity of the coating film, the handling property by an appropriate drying speed, Application for forming a high dielectric thin film capable of forming a dielectric thin film that is capable of forming a dielectric thin film that is excellent in dielectric properties, and that is capable of forming a thick film with an appropriate viscosity and is free from cracks. A composition and a method capable of efficiently producing the composition, and using the coating composition as a coating liquid, in a thin film capacitor, a capacitor insulating film of a semiconductor integrated circuit device, a capacitor material of a DRAM, and the like in an electronic device Since a high dielectric film useful for capacitor materials for various applications can be obtained, its industrial value is extremely large.

Hereinafter, the coating composition for forming a high dielectric thin film of the present invention and a method for producing the same will be described in detail.
1. Coating composition for forming a high dielectric thin film The coating composition for forming a high dielectric thin film of the present invention satisfies the following requirement (B) in a precursor solution that satisfies the following requirement (A). The resin component is contained in an amount of 0.2 to 2% by mass with respect to the precursor solution , and the viscosity is 4 to 15 mPa · s at 25 ° C.
(A) The precursor solution is selected from the group consisting of 1-butanol, 1-pentanol, 3methyl-1 butanol, 2methyl-1 butanol, 2-methyl-2-butanol, and 2-methyl-1-propanol. In a mixed solvent consisting of at least one alcohol selected from the group consisting of butyl acetate, propyl acetate, isopentyl acetate and butyl butyrate, and 2-ethylhexanoic acid, barium, strontium, An organic acid salt containing at least one metal element selected from the group consisting of magnesium and calcium and at least one metal element selected from the group consisting of titanium, tin and zirconium (hereinafter referred to as complex organic acid salt) And the metal element concentration is 0.4 to 1.2 mol / L.
(B) The resin component comprises at least one selected from diethyl maleate, dibutyl maleate, methacrylic acid amide, methyl methacrylate, butyl methacrylate, butyl acrylate, and copolymers thereof.

The coating composition for forming a high dielectric thin film of the present invention can satisfy the solubility, coating property, storage stability, etc. of the complex organic acid salt, and can be applied in forming a dielectric thin film by the MOD method. Improvement in productivity due to film uniformity, handling at an appropriate drying speed, and increased productivity due to an appropriate viscosity, and the generation of a dielectric thin film with excellent dielectric properties without cracks. It can be formed.
That is, when the coating composition is used as a coating solution, it is applied once on a silicon substrate in which a platinum film is formed on an oxide intermediate film, and then processed by spin coating at 1500 rpm for 20 seconds, and thereafter A high dielectric thin film obtained by firing at a temperature of 800 ° C. at a temperature of 120 to 350 nm is obtained. Moreover, in a high dielectric thin film obtained by spin coating on a silicon substrate having a platinum film formed on an oxide intermediate film and then firing at a temperature of 800 ° C., the film thickness is 200 to 300 nm. In some cases, the relative dielectric constant is 600 or more.

  In the coating composition, at least selected from the group consisting of 1-butanol, 1-pentanol, 3methyl-1-butanol, 2methyl-1-butanol, 2-methyl-2-butanol, and 2-methyl-1-propanol. In addition to a precursor solution containing at least one ester selected from the group consisting of one alcohol, butyl acetate, propyl acetate, isopentyl acetate and butyl butyrate, and a mixed solvent consisting of 2-ethylhexanoic acid, a resin It is important to include ingredients. As a result, suitable wettability and viscosity can be obtained, and problems such as uniformity of the coating film, flatness of the film surface, thickening, and high handling properties with an appropriate drying speed can be achieved. At the same time, the long-term stability, applicability at the time of film formation, decomposability at the time of film heat treatment, denseness of the film, and the like are good as compared with the conventional coating liquid containing no resin component.

  That is, by appropriately selecting the organic solvent used for the precursor solution, the solubility, coating properties, storage stability, film crystallinity, and production stability of the complex organic acid salt can be satisfied. Here, when a carboxylic acid, an ester, or an alcohol is used singly or in only one or two kinds, problems such as deterioration of the coating composition and deterioration of electrical characteristics occur. And since the organic solvent with low water miscibility is selected for the said mixed solvent, the coating composition of the preservability superior to the past is obtained.

That is, in general, in a precursor solution mainly composed of alcohol or the like, drying of a coating film starts immediately after spin coating, and uneven drying or repelling tends to occur depending on the location. In particular, when a large substrate is used, pinhole-shaped hole defects are also observed visually. These problems can be solved by preparing a working environment, but the workability is inferior. For this reason, to improve liquid stabilization, diketones such as acetylacetone and ethyl acetoacetate are added in an equimolar amount or more to the alkoxide for chelation treatment, or methyl cellosolve is used as the solvent alcohol and dissolved. In order to improve the liquid storage stability after synthesis, a method of distilling at 115 ° C. or higher and removing the low boiling point material having a boiling point of less than 115 ° C. produced by the reaction is employed.
On the other hand, in the precursor solution, since a highly water-resistant solvent is used, the generated complex organic acid salt has high water resistance, and is not affected by the low boiling point material generated during the reaction. Can keep stability.

On the other hand, the mixing of the low boiling point material produced affects the water resistance of the liquid, but the product has high thermal decomposability. Therefore, there is an effect that it becomes easy to crystallize even at a low temperature during coating. In particular, a low boiling point material having a boiling point of less than 115 ° C. is highly effective. For this reason, in the above precursor solution, the temperature at the time of heat synthesis is set to 110 ° C. or lower so that the low-boiling material having a boiling point of less than 115 ° C. produced by reaction is included in the liquid without distilling off. It is.
Here, the low boiling point material having a boiling point of less than 115 ° C. contained in the precursor is 1% by volume or more, preferably 2 to 60% by volume. The content of these low-boiling materials is calculated from the intensity of the detection spectrum obtained by the GCMS analysis method.

In addition, by selecting the resin component appropriately, the viscosity of the coating composition is raised to an appropriate range, and the number of coatings to obtain the desired film thickness of the high dielectric thin film is increased due to the increase in viscosity. Can be greatly reduced.
For example, in the case of using a conventional coating solution that does not contain the resin component, the film thickness of the high dielectric thin film obtained by a single coating is about 60 to 80 nm after baking at 800 ° C. In addition, when using for a general thin film capacitor etc., as a film thickness, 200 nm or more is required. Therefore, in order to obtain a desired film thickness, the coating film operation must be repeated 3 to 4 times. As an improvement measure, a method of increasing the concentration of the metal element constituting the high dielectric in the coating composition is conceivable. However, if the coating thickness is increased once by this method, film cracking occurs after firing. For example, when the metal element concentration is applied at 1.4 mol / L, the film thickness of the high dielectric thin film obtained by a single coating can greatly exceed 100 nm after baking at 800 ° C. However, cracks occur on the film surface during firing, and even the dielectric properties cannot be measured.

  As the resin component, diethyl maleate, dibutyl maleate, methacrylic acid amide, methyl methacrylate, butyl methacrylate, butyl acrylate or a copolymer thereof is used. In addition, when the average molecular weight of a polymer and a copolymer becomes 200,000 or more, it becomes impossible to dissolve in the mixed solvent. By containing the above resin component, the film thickness of the high dielectric thin film obtained by coating once is about 120 to 350 nm after baking at 800 ° C., and the number of coatings for obtaining a desired film thickness. Can be greatly reduced.

  As a content rate in the coating composition of the said resin component, it is 0.2-2 mass% with respect to a precursor solution. That is, when the content ratio of the resin component is less than 0.2% by mass, the wettability and the viscosity are low, and the effect of increasing the thickness is reduced. On the other hand, when the addition ratio exceeds 2% by mass, the film surface becomes uneven when the coating film is baked.

The complex organic acid salt used for the precursor solution is at least one metal element selected from the group consisting of barium, strontium, magnesium and calcium, and at least one metal selected from the group consisting of titanium, tin and zirconium An organic acid salt containing an element, and barium titanate (BaTiO ₃ ), strontium titanate (SrTiO ₃ ), calcium titanate (CaTiO ₃ ), barium strontium titanate ((Ba, Sr) TiO ₃ ) ) And the like, and a perovskite type complex oxide having high dielectric properties.

  The metal element concentration in the precursor solution is 0.4 to 1.2 mol / L. That is, when the metal element concentration is less than 0.4 mol / L, the concentration of the resulting coating composition is dilute, and thus the thickness of the high dielectric thin film formed by one coating is thin. Increases and productivity decreases. On the other hand, if the metal element concentration exceeds 1.2 mol / L, the concentration of the resulting coating composition becomes high, and film cracking occurs during baking of the coating film.

The viscosity of the said coating composition uses the thing of 4-15 mPa * s by the evaluation method (25 degreeC ) described in an Example, for example. That is, when the viscosity is less than 4 mPa · s, the thickness of the coating film is not improved. On the other hand, when the viscosity exceeds 15 mPa · s, the film thickness distribution is uneven when spin coating is performed. Furthermore, the resin component not only makes it less susceptible to the influence of outside air during drying, but does not cause problems such as cracks and voids. In addition, since a resin component having excellent thermal decomposability is selected, no residue is formed during firing, and no deterioration is observed in the dielectric properties of the high dielectric thin film.

Furthermore, the coating composition further coats a highly uneven surface even when the conventional coating liquid not containing the resin component is used on an oxide substrate or the like that is unsuitable due to its low viscosity and poor wettability. However, there is a great advantage that the flatness of the film surface can be improved.
That is, for example, in the production of an EL element, an electrode and a dielectric paste are applied on a glass substrate and heated to form a dielectric layer of several microns. Usually, large holes and cracks are caused by the volatilization of resin and paste components. Arise. If there are defects on the surface of the dielectric layer, porous film quality, uneven shape, etc., the light-emitting layer formed by vapor deposition such as evaporation or sputtering follows the surface shape and is smooth. Can not be formed. Since an electric field cannot be effectively applied to the light emitting layer portion formed on such a non-flat portion of the substrate, the effective light emitting area is reduced or the light emitting layer is formed due to local nonuniformity in film thickness. There is a problem that dielectric breakdown partially occurs, resulting in a decrease in light emission luminance. For this reason, the vehicle component (glass etc.) of the dielectric paste has been devised, but it has not been solved. In addition, when the conventional coating solution is used, the solution is repelled in a so-called eyeball shape so that the bottom of the hole is widened. On the other hand, if the coating composition for forming a high dielectric thin film of the present invention is used, the surface of the hole can be smoothly coated without deteriorating characteristics by using a dielectric material having the same composition. Can be repaired.

2. Method for producing coating composition for forming high dielectric thin film A method for producing a coating composition for forming a high dielectric thin film according to the present invention is a method for producing the coating composition for forming a high dielectric thin film. To the precursor solution that satisfies the following requirement (a), 0.2 to 2% by mass of a resin component that satisfies the following requirement (b) is added to the precursor solution, and then air or inert Stirring is performed at a temperature of 100 to 130 ° C. in a gas atmosphere.
(A) The precursor solution is from the group consisting of 1-butanol, 1-pentanol, 3methyl-1 butanol, 2methyl-1 butanol, 2-methyl-2-butanol, and 2-methyl-1-propanol. In a mixed solvent consisting of at least one alcohol selected from the group consisting of butyl acetate, propyl acetate, isopentyl acetate and butyl butyrate, and 2-ethylhexanoic acid, barium, strontium, It contains an organic acid salt containing at least one metal element selected from the group consisting of magnesium and calcium and at least one metal element selected from the group consisting of titanium, tin and zirconium, and the metal element concentration is 0 .4 to 1.2 mol / L.
(B) The resin component is composed of at least one selected from diethyl maleate, dibutyl maleate, methacrylamide, methyl methacrylate, butyl methacrylate, butyl acrylate, and copolymers thereof.

Although it does not specifically limit as a manufacturing method of the precursor solution used for the manufacturing method of the said coating composition, The thing containing following process (1)-(3) is preferable.
Step (1): at least one selected from the group consisting of 1-butanol, 1-pentanol, 3methyl-1-butanol, 2methyl-1-butanol, 2-methyl-2-butanol, and 2-methyl-1-propanol At least one ester selected from the group consisting of various alcohols, butyl acetate, propyl acetate, isopentyl acetate and butyl butyrate, and a mixed solvent consisting of 2-ethylhexanoic acid are mixed, and 100 under an inert gas atmosphere. While refluxing at a temperature of ˜110 ° C., a metal of at least one alkaline earth metal element selected from the group consisting of barium, strontium, magnesium and calcium, an alkoxide or a carboxylate thereof, is added, stirred, and metal An organic acid salt solution (A) having an element concentration of 0.4 to 1.2 mol / L is prepared.
Step (2): An alkoxide of at least one element selected from the group consisting of titanium, tin and zirconium is converted into 1-butanol, 1-pentanol, 3methyl-1-butanol, 2methyl-1butanol, 2-methyl- At least one alcohol selected from the group consisting of 2-butanol and 2-methyl-1-propanol, or at least one ester selected from the group consisting of butyl acetate, propyl acetate, isopentyl acetate and butyl butyrate It adds in the solvent which consists of one, and stirs at the temperature of 20-60 degreeC under air | atmosphere, and prepares the alkoxide liquid (B) whose metal element density | concentration is 0.4-1.2 mol / L.
Step (3): The organic acid salt solution (A) and the alkoxide solution (B) are cooled, and then both are combined with the total amount of metal elements contained in the former and the total amount of metal elements contained in the latter. Are mixed at a blending ratio such that and are equal in molar ratio, and then stirred at a temperature of 100 to 110 ° C. in an inert gas atmosphere to synthesize a precursor solution.

In the step (1), a mixed solvent composed of the alcohols, the esters, and 2-ethylhexanoic acid is mixed in a desired composition and heated while refluxing at a temperature of 100 to 110 ° C. in an inert gas atmosphere. Keep it. In this mixed solvent, at least one kind of alkaline earth metal element metal, alkoxide or carboxylate thereof is added, and preferably dissolved by stirring for 1 to 3 hours.
Depending on the form of the alkaline earth metal element used, care must be taken because the temperature rises significantly due to the heat of dissolution as the dissolution proceeds. Thereby, an organic acid salt solution (A) having a metal element concentration of 0.4 to 1.2 mol / L is prepared.

The carboxylate is not particularly limited, but carboxylates such as barium acetate, calcium acetate and calcium ethylhexanoate are preferable.
The alkoxide is not particularly limited, and examples thereof include at least one alkaline earth metal element methoxide, ethoxide, isopropoxide, butoxide selected from the group consisting of barium, strontium, magnesium and calcium. However, it is particularly preferable to use isopropoxide or butoxide because of an appropriate reaction rate.

  The mixing ratio of the mixed solvent is not particularly limited, but the ester is preferably 50 to 200 parts by volume, more preferably 50 to 140 parts by volume, or 100 parts by volume of the alcohols. 2-ethylhexanoic acid is preferably 50 to 100 parts by volume, more preferably 50 to 70 parts by volume. That is, when the blending ratio is out of this range, dissolution becomes insufficient, undissolved substances are easily generated, precipitates are generated, and the liquid becomes unstable. Moreover, since liquid stability increases by this, even if it does not mix with an alkoxide liquid (B) and synthesize | combine immediately, if it puts in an airtight container, what will not change at all for three months will be obtained.

  On the other hand, when the organic solvents such as ethers, alcohols, carboxylic acids or esters are used alone or in any combination other than the conditions of the present invention, the above effects cannot be obtained. For example, when a metal is used as a raw material for an alkaline earth metal element, it easily dissolves in alcohols or ethers, but the resulting organic acid salt solution lacks stability to water and cannot be exposed to the outside air. In addition, there is a problem that storage stability is bad. Further, when a lower carboxylate is used as a raw material, many of them are difficult to dissolve in a lower alcohol, and therefore, generally dissolved using esters or carboxylic acids. However, when only esters are used, particles are precipitated during storage because the solubility of the carboxylate is low. Furthermore, there is a problem that the wettability with the metal film which is the base electrode of the dielectric thin film is poor and a uniform film cannot be obtained. On the other hand, carboxylic acids are useful organic solvents that have high solubility and low water miscibility, and thus stabilize storage stability, but are difficult to be volatilized and removed by heating. Therefore, when a large amount of carboxylic acid is used, an organic component remains during film formation. The same applies to a mixed solution of esters and carboxylic acids.

  The heating and melting conditions used in the step (1) are 100 to 110 ° C. That is, when the heating temperature is less than 100 ° C., the formation of the organic acid salt is insufficient. On the other hand, when the heating temperature exceeds 110 ° C., volatilization of the organic solvent becomes active. Moreover, it does not specifically limit as stirring time, 1-3 hours are preferable.

  The metal element concentration of the organic acid salt solution (A) obtained in the step (1) is 0.4 to 1.2 mol / L. That is, when the metal element concentration is less than 0.4 mol / L, the productivity is reduced because the concentration is dilute. On the other hand, when the metal element concentration exceeds 1.2 mol / L, the solution becomes insufficient and the solution is not stable. There is.

In the step (2), an alkoxide of at least one element selected from the group consisting of titanium, tin, and zirconium is added to the solvent of any of the alcohols or esters, and the atmosphere is 20-60. Stir at a temperature of ° C to dissolve. Thereby, an alkoxide liquid (B) having a metal element concentration of 0.4 to 1.2 mol / L is prepared.
In the above step (2), by selecting the raw material form, the organic solvent and the blending ratio thereof, an alkoxide liquid (B) excellent in safety at the time of production is obtained, and the dissolution of the metal in the alkoxide liquid (B) is obtained. The effect of satisfying the property and storage stability, the coating property of the coating composition for forming a high dielectric thin film, and volatilization or decomposability causing film defects can be obtained.

  The alkoxide used in the above step (2) is not particularly limited, and examples thereof include methoxide, ethoxide, isopropoxide, butoxide, and the like. Particularly, since the reaction rate is appropriate, isopropoxide or butoxide. Is preferably used.

  Although it does not specifically limit as heat dissolution conditions used at the said process (2), The temperature of 20-60 degreeC is preferable. That is, when the heating temperature is less than 20 ° C., the formation of the metal alkoxide is insufficient. On the other hand, when heating temperature exceeds 60 degreeC, volatilization of the organic solvent will become active. Moreover, it does not specifically limit as heating time, 0.2-2 hours are preferable, and the time when formation of metal alkoxide is fully performed is selected.

  The metal element concentration of the alkoxide liquid (B) obtained in the step (2) is 0.4 to 1.2 mol / L. That is, when the metal element concentration is less than 0.4 mol / L, the productivity decreases when the concentration is dilute. On the other hand, when the metal element concentration exceeds 1.2 mol / L, dissolution is insufficient and the liquid is not stable.

In the step (3), the organic acid salt solution (A) and the alkoxide solution (B) are cooled, and then both of the total amount of metal elements contained in the former and the amount of metal elements contained in the latter After mixing at a blending ratio such that the total amount is equal in molar ratio, the precursor solution is synthesized by stirring in an inert gas atmosphere at a temperature of 100 to 110 ° C., preferably for 2 to 10 hours.
In the step (3), by selecting the compounding ratio of the organic acid salt solution (A) and the alkoxide solution (B) under the above conditions, the solubility and storage property of the metal in the precursor solution, and the high dielectric thin film The effect which satisfies the coating-film property of the coating composition for formation, volatilization or decomposability which causes a film defect, etc. is acquired.

As heating conditions used at the said process (3), temperature is 100-110 degreeC. That is, when the heating temperature is less than 100 ° C., the synthesis reaction is insufficient, the formation of the complex organic acid salt does not proceed, and the constituent elements are present alone, resulting in a difference in hydrolysis rate and the uniformity of the film composition Is inferior. On the other hand, when the temperature exceeds 110 ° C., not only the volatilization of the solvent is activated, but the contents are also volatilized at the same time, resulting in a composition shift. Moreover, it does not specifically limit as heating time, 2-10 hours are preferable and the time for which synthesis | combination is fully performed is selected.
In the above precursor solution manufacturing method, step (1) and step (3) are carried out under reflux during heating, so there is no component that volatilizes from the solvent and there is no change in the liquid composition.

The manufacturing method of the said coating composition is the manufacturing method of the said precursor solution. After cooling the obtained precursor solution, the said resin component is 0.2 with respect to this precursor solution in this precursor solution. Add ~ 2 wt%, then heat to 100-130 ° C under air or inert gas atmosphere.
Here, the resin component is synthesized by a heating reaction with the precursor solution, and a coating composition containing the resin is formed. This increases the viscosity of the coating composition. Moreover, since the high water-resistant characteristic of resin is provided to a coating composition, long-term stability increases.

As a method for adding the resin component, the resin component can be directly added to the precursor solution. For example, the resin component can be added to 1-butanol, 1-pentanol, 3methyl-1butanol, 2methyl-1 Dissolution of a resin component obtained by dissolving in at least one solvent selected from the group consisting of butanol, 2-methyl-2-butanol, 2-methyl-1-propanol, butyl acetate, propyl acetate, isopentyl acetate and butyl butyrate It can also be performed in liquid.
The method for preparing the resin component solution is not particularly limited. For example, after blending the resin component in the solvent, the mixture is heated at a temperature of 60 ° C. or more for 1 hour or more and then allowed to cool overnight. By doing so, it is preferable to dissolve completely.

  The synthesis temperature of the coating composition is 100 to 130 ° C. That is, when the temperature is less than 100 ° C., the synthesis is insufficient, and the effect on the wettability of the liquid becomes dilute. On the other hand, when temperature exceeds 130 degreeC, volatilization of a dilution liquid will become active and control of a liquid composition will become difficult. In addition, the heating time is not particularly limited, and is preferably 1 hour or longer, and more preferably 1 to 3 hours in order to sufficiently promote heat synthesis.

  The metal element concentration of the coating composition is, for example, 0.2 to 0.8 mol / L. That is, when the metal element concentration is less than 0.2 mol / L, the concentration is dilute and the productivity is lowered. On the other hand, when the metal element concentration exceeds 0.8 mol / L, film cracking occurs during the film heat treatment. In addition, adjustment of the metal element density | concentration of the said coating composition is performed by adding the solution containing the said resin component to the said precursor solution. For example, an appropriate amount of a resin is added to a solvent mixed with 1-butanol and butyl acetate and dissolved, and this is used as a diluent to mix with the precursor solution to obtain a coating composition whose concentration is adjusted.

By using the coating composition for forming a high dielectric thin film as a coating liquid, it is possible to obtain a high dielectric film with no cracks and excellent dielectric characteristics. For example, when the thickness of a high dielectric thin film obtained by spin coating on a silicon substrate on which a platinum film is formed and then firing at a temperature of 800 ° C. is 200 to 300 nm, the relative dielectric constant is 600. That's it.
As a method for forming the high dielectric film, first, a coating solution is dropped on a substrate, and then applied by spin coating, dip coating or the like and dried. Next, temporary baking is performed at a temperature of 400 to 600 ° C. for about 10 minutes to 1 hour. Here, in order to obtain a desired film thickness, the multilayer dielectric thin film obtained by repeatedly applying, drying, and pre-baking several times is subjected to main baking at a temperature of 700 to 900 ° C. for about 20 minutes to 2 hours. A dielectric film is obtained.
Examples of the substrate include a silicon substrate in which a platinum film is formed on an oxide intermediate film, such as Ru / RuO ₂ / SiO ₂ / Si, RuO ₂ / Si, Ir / IrO ₂ / Si, and Pt / Ir / IrO. ₂ / Si, Pt / IrO ₂ / Si, Pt / TiO ₂ / Si, Pt / TiO ₂ / SiO ₂ / Si, and the like.

Hereinafter, the present invention will be described in more detail by way of examples and comparative examples of the present invention, but the present invention is not limited to these examples. In addition, the evaluation method of the coating composition and the formation method and evaluation method of a thin film which were used by the Example and the comparative example are as follows.
(1) Metal analysis: ICP emission analysis was performed.
(2) Evaluation method of coating composition: The following (i) to (d) were measured.
(A) Viscosity measurement of the coating composition: The room temperature was kept at 25 ° C. and measured for 5 minutes using a B-type rotary viscometer.
(B) Drying speed measurement of coating composition: The coating solution is applied onto a Pt / TiO ₂ / SiO ₂ / Si substrate by spin coating, dried at 120 ° C. for 10 minutes, and the rate of decrease is determined from the change in mass before and after drying. Calculated. When this reduction rate is large, the drying speed is fast.
(C) Evaluation of coating film uniformity: The coating solution is applied onto a Pt / TiO ₂ / SiO ₂ / Si substrate by spin coating, and a 2 mm square field of view is observed with a stereomicroscope to evaluate the occurrence of pinholes. did.
(D) Preservability of coating composition: The coating composition was allowed to stand at 30 ° C. × 60% RH for 10 days, and then the state of the liquid was visually observed.
(3) Thin film formation method and evaluation method: The coating solution was applied on a Pt / TiO ₂ / SiO ₂ / Si substrate by spin coating at a rotation speed of 1500 rpm for 20 seconds, dried at 150 ° C., and then in air 600 Pre-baking was performed at 30 ° C. for 30 minutes. Coating, drying, and pre-baking were repeated a predetermined number of times, followed by main baking at 800 ° C. for 30 minutes in an oxygen gas stream to form a thin film. Meanwhile, the film thickness and crack generation of the thin film were evaluated by the following methods (e) and (f).
(E) Measurement of the film thickness of the thin film: Measured with a step gauge to determine the film thickness per application.
(F) Crack generation state of thin film: Cracks on the film surface were observed by AFM observation.
Further, a platinum upper electrode of φ0.4 mm was provided thereon, and the relative dielectric constant and dielectric loss were calculated by obtaining the electrostatic capacity at an AC voltage of 1.0 V and a frequency of 1 MHz.

Example 1
First, barium metal is added to a mixed solvent containing 2-methyl-1-butanol: 2-ethylhexanoic acid: butyl acetate = 2: 1: 1 by volume ratio, and stirred and mixed at 110 ° C. for 2 hours in a nitrogen stream. Then, a barium organic acid salt solution (A) having a Ba concentration of 1.0 mol / L was prepared. Further, titanium tetraisopropoxide was added to butyl acetate, and the mixture was stirred and mixed in the atmosphere at 25 ° C. for 0.4 hours to prepare a titanium alkoxide liquid (B) having a Ti concentration of 1.0 mol / L.
Next, the titanium alkoxide liquid (B) is dropped into the barium organic acid salt liquid (A) so that the molar ratio is barium: titanium = 1: 1, and the mixture is stirred and mixed at 110 ° C. for 2 hours in a nitrogen stream. A precursor solution having a metal element concentration of 1.0 mol / L was obtained.
Subsequently, after adding 1.0 mass% of diethyl maleate as a resin component to the precursor solution with respect to the precursor solution, the mixture was stirred and mixed in nitrogen at 110 ° C. for 2 hours to obtain a coating composition. The resulting coating composition was measured for viscosity, drying speed, storage stability, and pinhole occurrence of the coating film according to the method for evaluating the coating composition.
Thereafter, in accordance with the thin film formation method and the evaluation method, coating, drying, and pre-baking are repeated twice to form a BaTiO ₃ thin film, and the thin film thickness and crack generation are evaluated, and the relative dielectric constant and dielectric loss are evaluated. It was. The results are shown in Tables 1-3.

(Example 2)
Except for adding 2.0% by mass of dibutyl maleate as a resin component to the precursor solution, the viscosity of the coating composition obtained, the drying rate, Preservability, the state of occurrence of pinholes in the coating film, the film thickness and crack generation of the obtained BaTiO ₃ thin film, and the relative dielectric constant and dielectric loss were evaluated. The results are shown in Tables 1-3. In addition, the wettability of the coating composition was good.

(Example 3)
Instead of the resin component, the following resin component solution (C) was added to the precursor solution so that the resin component was 0.2% by mass with respect to the precursor solution, and the temperature at this time was 100. The viscosity, drying speed, and storage stability of the coating composition obtained were the same as in Example 1 except that the coating temperature was 1 ° C. and that the coating method was performed once in the thin film formation method and evaluation method. , And the state of occurrence of pinholes in the coating film, the film thickness and crack generation of the obtained BaTiO ₃ thin film, and the relative dielectric constant and dielectric loss were evaluated. The results are shown in Tables 1-3. In addition, the wettability of the coating composition was good.
[Resolution of resin component (C)]
A copolymer of butyl methacrylate and butyl acrylate blended at a volume ratio of 1: 1 (average molecular weight 150,000) was added to a mixed solvent blended at a volume ratio of 1-butanol: butyl acetate = 3: 1. I got it. Concentration 50% by mass.

Example 4
Instead of the resin component, the following resin component solution (C) was added to the precursor solution so that the resin component was 0.5% by mass with respect to the precursor solution, and the temperature at this time was 100. The viscosity, drying speed, and storage stability of the coating composition obtained were the same as in Example 1 except that the coating temperature was 1 ° C. and that the coating method was performed once in the thin film formation method and evaluation method. , And the state of occurrence of pinholes in the coating film, the film thickness and crack generation of the obtained BaTiO ₃ thin film, and the relative dielectric constant and dielectric loss were evaluated. The results are shown in Tables 1-3. In addition, the wettability of the coating composition was good.
[Resolution of resin component (C)]
A copolymer of butyl methacrylate and butyl acrylate blended at a volume ratio of 1: 1 (average molecular weight 150,000) was added to a mixed solvent blended at a volume ratio of 1-butanol: butyl acetate = 3: 1. I got it. Concentration 50% by mass.

(Example 5)
Instead of the resin component, the following resin component solution (D) was added to the precursor solution so that the resin component was 1% by mass with respect to the precursor solution, and the temperature at this time was 125 ° C. Except that the stirring time was 1 hour, and in the thin film formation method and the evaluation method described above, the coating composition was obtained in the same manner as in Example 1 except that the coating was performed once. Evaluation was made on speed, storage stability, pinhole occurrence of the coating film, film thickness and crack generation of the obtained BaTiO ₃ thin film, and dielectric constant and dielectric loss. The results are shown in Tables 1-3. In addition, the wettability of the coating composition was good.
[Resolution of resin component (D)]
It was obtained by adding methyl methacrylate (average molecular weight 10,000) and dibutyl maleate blended at a volume ratio of 1: 2 into 2-methyl-1-propanol. Concentration 20% by mass.

(Example 6)
Instead of the resin component, the following resin component solution (E) was added to the precursor solution so that the resin component was 1% by mass with respect to the precursor solution, and the temperature at this time was 125 ° C. Except that the stirring time was 1 hour, and in the thin film formation method and the evaluation method described above, the coating composition was obtained in the same manner as in Example 1 except that the coating was performed once. Evaluation was made on speed, storage stability, pinhole occurrence of the coating film, film thickness and crack generation of the obtained BaTiO ₃ thin film, and dielectric constant and dielectric loss. The results are shown in Tables 1-3. In addition, the wettability of the coating composition was good.
[Resolution of resin component (E)]
Methacrylic acid amide was obtained by adding it in 3-methyl-1-butanol. Concentration 20% by mass.

(Example 7)
First, metal barium and metal calcium having a molar ratio of 9: 1 were added to a mixed solvent containing 2-methyl-1-butanol: 2-ethylhexanoic acid: butyl acetate = 2: 1: 1 by volume ratio. Then, the mixture was stirred and mixed in a nitrogen stream at 110 ° C. for 5 hours to prepare a barium calcium organic acid salt solution (A) having a metal element concentration of 0.4 mol / L. Further, titanium tetraisopropoxide and zirconium tetrabutoxide blended so that the molar ratio of titanium: zirconium = 8: 2 is added to 2-methyl-1-propanol and stirred at 25 ° C. in the atmosphere for 0.4 hours. By mixing, a titanium zirconium alkoxide liquid (B) having a Ti concentration of 0.4 mol / L was prepared.
Next, the titanium zirconium alkoxide solution (B) is dropped into the barium calcium organic acid salt solution (A) so that the total amount of barium and calcium: the total amount of titanium and zirconium = 1: 1 by molar ratio, The mixture was stirred and mixed at 110 ° C. for 4 hours in a nitrogen stream to obtain a precursor solution having a metal element concentration of 0.4 mol / L.
Next, the resin component solution (C) was added to the precursor solution so that the resin component was 2% by mass with respect to the precursor solution, and then the mixture was stirred and mixed at 100 ° C. for 1 hour in the atmosphere. Obtained. The resulting coating composition was measured for viscosity, drying speed, storage stability, and pinhole occurrence of the coating film according to the method for evaluating the coating composition.
Then, according to the thin film formation method and the evaluation method, a (Ba _0.9 Ca _0.1 ) (Ti _0.8 Zr _0.2 ) O ₃ thin film is formed by a single coating, and the film thickness and cracks of the thin film Evaluation of generation and evaluation of relative permittivity and dielectric loss were performed. The results are shown in Tables 1-3. In addition, the wettability of the coating composition was good.
[Resolution of resin component (C)]
A copolymer of butyl methacrylate and butyl acrylate blended at a volume ratio of 1: 1 (average molecular weight 150,000) was added to a mixed solvent blended at a volume ratio of 1-butanol: butyl acetate = 3: 1. I got it. Concentration 50% by mass.

(Example 8)
The following resin component solution (F) was added to the precursor solution so that the resin component was 1.0 mass% with respect to the precursor solution, and the stirring time was 2 hours. In the thin film forming method and the evaluation method, except that coating, drying, and pre-baking were repeated twice, the same procedure as in Example 7 was performed, and the viscosity, drying rate, storage stability, And the state of occurrence of pinholes in the coating film, the film thickness of the obtained (Ba _0.9 Ca _0.1 ) (Ti _0.8 Zr _0.2 ) O ₃ thin film, evaluation of crack generation, and relative dielectric constant Dielectric loss was evaluated. The results are shown in Tables 1-3. In addition, the wettability of the coating composition was good.
[Resolution of resin component (F)]
It was obtained by adding methyl methacrylate (average molecular weight 10,000) into a mixed solvent blended in a volume ratio of 2-methyl-1-propanol: isopentyl acetate = 4: 1. Concentration 20% by mass.

Example 9
The following resin component solution (G) was added to the precursor solution so that the resin component was 0.5% by mass with respect to the precursor solution, and the stirring time was 2 hours. In the thin film forming method and the evaluation method, except that coating, drying, and pre-baking were repeated twice, the same procedure as in Example 7 was performed, and the viscosity, drying rate, storage stability, In addition, the state of occurrence of pinholes in the coating film, the film thickness and crack generation of the obtained BaTiO ₃ thin film, and the relative dielectric constant and dielectric loss were evaluated. The results are shown in Tables 1-3. In addition, the wettability of the coating composition was good.
[Resolution of resin component (G)]
It was obtained by adding butyl acrylate (average molecular weight 8000) in a mixed solvent blended with 1-butanol: butyl acetate = 3: 1 by volume ratio. Concentration 20% by mass.

(Comparative Example 1)
Same as Example 1 except that the precursor solution was used as it was without adding a resin component, and the coating method, the drying method, and the preliminary firing were repeated three times in the thin film formation method and the evaluation method. The viscosity, drying speed, storage stability, and pinhole occurrence of the coating film, evaluation of film thickness and crack generation of the obtained BaTiO ₃ thin film, relative dielectric constant and dielectric loss Was evaluated. The results are shown in Tables 1-3.

(Comparative Example 2)
In the unsealed state, the precursor solution was heated to 135 ° C. and concentrated to a concentration of 1.4 mol / L, and the coating solution was used as it was without adding the resin component. The coating composition was obtained in the same manner as in Example 1 except that the viscosity of the coating composition, the drying speed, the storage stability, the pinhole occurrence of the coating film, and the resulting BaTiO ₃ thin film were obtained. The film thickness and crack generation were evaluated, and the relative dielectric constant and dielectric loss were evaluated. The results are shown in Tables 1-3.

(Comparative Example 3)
Instead of the resin component, the same solution (H) of the following resin component was added to the precursor solution as in Example 1 except that the resin component was 1% by mass with respect to the precursor solution. As a result, the obtained coating composition gelled. The results are shown in Tables 1-3.
[Resolution of resin component (H)]
Polyvinyl butyral (average molecular weight 1500) was obtained by adding into 1-butanol. Concentration 5% by mass.

(Comparative Example 4)
Example 1 except that 5.0% by mass of propylene glycol as a resin component was added to the precursor solution with respect to the precursor solution and that the temperature was 100 ° C. and the stirring time was 1 hour. In the same manner as above, the viscosity, drying speed, storage stability, and pinhole occurrence of the coating film, evaluation of the film thickness and crack generation of the obtained BaTiO ₃ thin film, and the relative dielectric constant Dielectric loss was evaluated. The results are shown in Tables 1-3.

(Comparative Example 5)
Same as Example 7 except that the precursor solution was used as a coating solution without adding a resin component, and that the coating, drying, and pre-baking were repeated four times in the thin film formation method and the evaluation method. The viscosity of the (Ba _0.9 Ca _0.1 ) (Ti _0.8 Zr _0.2 ) O ₃ coating composition obtained, the drying speed, the storage stability, and the occurrence of pinholes in the coating film The film thickness and crack generation of the obtained thin film were evaluated, and the relative dielectric constant and dielectric loss were evaluated. The results are shown in Tables 1-3.

(Comparative Example 6)
Other than that the solution (I) of the next resin component was added to the precursor solution so that the resin component was 5% by mass with respect to the precursor solution, and the stirring time at this time was 2 hours Was carried out in the same manner as in Example 7, and the viscosity, drying speed, storage stability, and pinhole occurrence of the coating film were obtained and the obtained (Ba _0.9 Ca _0.1 ) ( The film thickness and crack generation of the Ti _0.8 Zr _0.2 ) O ₃ thin film were evaluated, and the relative dielectric constant and dielectric loss were evaluated. The results are shown in Tables 1-3. [Resolution of resin component (I)]
Methyl methacrylate (average molecular weight 10,000) was obtained by adding it to a mixed solvent blended with ethanol: toluene = 3: 1 by volume ratio. Concentration 20% by mass.

(Comparative Example 7)
Other than that the solution (J) of the next resin component was added to the precursor solution so that the resin component was 7% by mass with respect to the precursor solution, and the stirring time at this time was 2 hours Was carried out in the same manner as in Example 7. As a result, the obtained coating composition gelled. The results are shown in Tables 1-3.
[Resolution of resin component (J)]
Polyvinyl butyral (average molecular weight 1500) was obtained by adding it to a mixed solvent blended in a volume ratio of ethanol: terpineol = 3: 1. Concentration 20% by mass.

(Comparative Example 8)
In the precursor solution, the following resin component solution (K) was added so that the resin component was 1.0% by mass with respect to the precursor solution, and the thin film formation method and evaluation method were applied. Except that the drying and pre-baking were repeated three times, it was carried out in the same manner as in Example 7, and the viscosity, drying speed, storage stability, and pinhole occurrence of the coating film obtained and obtained. Further, the thickness of the (Ba _0.9 Ca _0.1 ) (Ti _0.8 Zr _0.2 ) O ₃ thin film, evaluation of occurrence of cracks, and evaluation of relative permittivity and dielectric loss were performed. The results are shown in Tables 1-3.
[Resolution of resin component (K)]
A copolymer of styrene and maleic acid blended at a volume ratio of 1: 3 (average molecular weight 5000) was added to a mixed solvent blended at a volume ratio of 1-butanol: butyl acetate = 3: 1. Concentration 20% by mass.

  From Tables 1-3, in Examples 1-9, the coating composition which contains a specific resin component in a specific addition ratio in the precursor solution which contains a specific organic acid salt in a specific ratio in a specific mixed solvent. Since it was carried out according to the present invention using a product, the uniformity of the coating film due to the increase in wettability, the handling property due to an appropriate drying speed, and the improvement in productivity for increasing the film thickness due to appropriate wettability and viscosity It can be seen that a dielectric thin film with no cracks and excellent dielectric properties can be formed.

  On the other hand, in Comparative Examples 1 to 8, since the resin component or the addition ratio thereof does not meet the conditions of the present invention, an appropriate viscosity cannot be obtained in the obtained coating composition, or the drying speed is high. It can be seen that cracks occur in the dielectric thin film and the dielectric properties are low, so that satisfactory results cannot be obtained. In Comparative Example 3 or 7, there is a problem that the coating composition cannot be applied due to gelation, and satisfactory results cannot be obtained.

  As is apparent from the above, the coating composition for forming a high dielectric thin film and the method for producing the same according to the present invention are used in various applications in electronic devices such as thin film capacitors, capacitive insulating films of semiconductor integrated circuit devices, and capacitor materials of DRAMs. It is suitable as a coating composition for forming a high dielectric thin film used for a high dielectric film such as a capacitor material and a method for producing the same.

Claims (7)

In the precursor solution that satisfies the following requirement (A), the resin component that satisfies the following requirement (B) is contained in an amount of 0.2 to 2% by mass with respect to the precursor solution , and the viscosity is 25 ° C. 4. A coating composition for forming a high dielectric thin film, wherein the coating composition is 4 to 15 mPa · s .
(A) The precursor solution is selected from the group consisting of 1-butanol, 1-pentanol, 3methyl-1 butanol, 2methyl-1 butanol, 2-methyl-2-butanol, and 2-methyl-1-propanol. In a mixed solvent consisting of at least one alcohol selected from the group consisting of butyl acetate, propyl acetate, isopentyl acetate and butyl butyrate, and 2-ethylhexanoic acid, barium, strontium, It contains an organic acid salt containing at least one metal element selected from the group consisting of magnesium and calcium and at least one metal element selected from the group consisting of titanium, tin and zirconium, and the metal element concentration is 0 .4 to 1.2 mol / L.
(B) The resin component comprises at least one selected from diethyl maleate, dibutyl maleate, methacrylic acid amide, methyl methacrylate, butyl methacrylate, butyl acrylate, and copolymers thereof.   When used as a coating solution, it is applied once on a silicon substrate in which a platinum film is formed on an oxide intermediate film, then processed by spin coating at 1500 rpm for 20 seconds, and then baked at a temperature of 800 ° C. The coating composition for forming a high dielectric thin film according to claim 1, wherein the thickness of the high dielectric thin film obtained is 120 to 350 nm.   When used as a coating solution, the film thickness of a high dielectric thin film obtained by spin coating on a silicon substrate having a platinum film formed on an oxide intermediate film and then firing at a temperature of 800 ° C. 2. The coating composition for forming a high dielectric thin film according to claim 1, wherein the dielectric constant is 600 or more when the thickness is 200 to 300 nm. To the precursor solution that satisfies the following requirement (a), 0.2 to 2% by mass of a resin component that satisfies the following requirement (b) is added to the precursor solution, and then air or inert The method for producing a coating composition for forming a high dielectric thin film according to any one of claims 1 to 3 , wherein stirring is performed at a temperature of 100 to 130 ° C in a gas atmosphere.
(A) The precursor solution is from the group consisting of 1-butanol, 1-pentanol, 3methyl-1 butanol, 2methyl-1 butanol, 2-methyl-2-butanol, and 2-methyl-1-propanol. In a mixed solvent consisting of at least one alcohol selected from the group consisting of butyl acetate, propyl acetate, isopentyl acetate and butyl butyrate, and 2-ethylhexanoic acid, barium, strontium, It contains an organic acid salt containing at least one metal element selected from the group consisting of magnesium and calcium and at least one metal element selected from the group consisting of titanium, tin and zirconium, and the metal element concentration is 0 .4 to 1.2 mol / L.
(B) The resin component is composed of at least one selected from diethyl maleate, dibutyl maleate, methacrylamide, methyl methacrylate, butyl methacrylate, butyl acrylate, and copolymers thereof. The resin component may be added by adding the resin component to 1-butanol, 1-pentanol, 3methyl-1-butanol, 2methyl-1butanol, 2-methyl-2-butanol, 2-methyl-1-propanol, acetic acid. 5. The coating composition for forming a high dielectric thin film according to claim 4 , wherein the coating composition is a solution of a resin component dissolved in at least one solvent selected from the group consisting of butyl, propyl acetate, isopentyl acetate and butyl butyrate. Manufacturing method. The method for producing a coating composition for forming a high dielectric film according to claim 4 , wherein the precursor solution is obtained by a production method including the following steps (1) to (3).
Step (1): at least one selected from the group consisting of 1-butanol, 1-pentanol, 3methyl-1-butanol, 2methyl-1-butanol, 2-methyl-2-butanol, and 2-methyl-1-propanol At least one ester selected from the group consisting of various alcohols, butyl acetate, propyl acetate, isopentyl acetate and butyl butyrate, and a mixed solvent consisting of 2-ethylhexanoic acid are mixed, and 100 under an inert gas atmosphere. While refluxing at a temperature of ˜110 ° C., a metal of at least one alkaline earth metal element selected from the group consisting of barium, strontium, magnesium and calcium, an alkoxide or a carboxylate thereof, is added, stirred, and metal An organic acid salt solution (A) having an element concentration of 0.4 to 1.2 mol / L is prepared.
Step (2): An alkoxide of at least one element selected from the group consisting of titanium, tin and zirconium is converted into 1-butanol, 1-pentanol, 3methyl-1-butanol, 2methyl-1butanol, 2-methyl- At least one alcohol selected from the group consisting of 2-butanol and 2-methyl-1-propanol, or at least one ester selected from the group consisting of butyl acetate, propyl acetate, isopentyl acetate and butyl butyrate It adds in the solvent which consists of one, and stirs at the temperature of 20-60 degreeC under air | atmosphere, and prepares the alkoxide liquid (B) whose metal element density | concentration is 0.4-1.2 mol / L.
Step (3): The organic acid salt solution (A) and the alkoxide solution (B) are cooled, and then both are combined with the total amount of metal elements contained in the former and the total amount of metal elements contained in the latter. Are mixed at a blending ratio such that and are equal in molar ratio, and then stirred at a temperature of 100 to 110 ° C. in an inert gas atmosphere to synthesize a precursor solution. The mixing ratio of the mixed solvent used in the step (1) is characterized in that the ester is 50 to 200 parts by volume and the 2-ethylhexanoic acid is 50 to 100 parts by volume with respect to 100 parts by volume of the alcohol. A method for producing a coating composition for forming a high dielectric thin film according to claim 6 .