Water soluble composition, method for producing same, conductive composition, and method for producing same

Abstract

The present invention addresses the problem of providing: a conductive composition which has good coating properties and in which foreign matter is unlikely to occur when the conductive composition is made into a coating film; a method for producing the conductive composition; a water soluble composition which is used in the conductive composition; and a method for producing the water soluble composition. Provided is a water soluble composition that includes a water soluble polymer, said water soluble composition satisfying conditions (A1) and (A2). Also provided is a method for producing a water soluble composition, said method comprising a reprecipitation step for mixing a good solvent solution, which contains a water soluble composition and a good solvent of the water soluble composition, and a poor solvent of the water soluble composition, said poor solvent containing an ether.　The condition (A1) is that the water soluble polymer contains a nitrogen-containing functional group.　The condition (A2) is that surface tension of a 1.0 mass% aqueous solution of the water soluble composition at 25°C is 34.0-50.0.

Description

Water-soluble composition and method for producing the same, and conductive composition and method for producing the same

[0001] The present invention relates to a water-soluble composition and a method for producing the same, and a conductive composition and a method for producing the same. This application claims priority based on Japanese Patent Application No. 2023-097824, filed on June 14, 2023, the contents of which are incorporated herein by reference.

[0002] Pattern formation technology using charged particle beams, such as electron beams and ion beams, is expected to be the next-generation technology of optical lithography. When using charged particle beams, improving the sensitivity of the resist layer is important for improving productivity. Therefore, the use of highly sensitive chemically amplified resists, which generate acid in exposed areas or areas irradiated with the charged particle beam, followed by a heating process called post-exposure bake (PEB) treatment to promote crosslinking or decomposition reactions, has become mainstream. Furthermore, with the recent trend toward miniaturization of semiconductor devices, there has been an increasing demand for control of resist shape on the order of several nanometers.

[0003] However, in a pattern formation method using a charged particle beam, there is a problem that, particularly when the substrate is insulating, the trajectory of the charged particle beam is bent due to an electric field generated by charging (charging up) of the substrate, making it difficult to obtain a desired pattern. As a means for solving this problem, a technique has already been known to be effective in which a conductive composition containing a conductive polymer is applied to the surface of a resist layer to form a coating film, and the surface of the resist layer is covered with the coating film to impart antistatic properties to the resist layer.

[0004] In general, a surfactant is added to a conductive composition for the purpose of improving coatability, etc. For example, Patent Document 1 discloses a conductive composition that contains, in addition to a conductive polymer, a water-soluble polymer having a nitrogen-containing functional group and a terminal hydrophobic group, as a conductive composition that has excellent coatability, etc.

[0005] Japanese Patent Application Laid-Open No. 2002-226721

[0006] However, if a conductive composition contains a component that causes defects (defect-causing component), the component may aggregate during film formation and appear as foreign matter in the coating film. A coating film containing the foreign matter can cause problems such as line breakage after electron beam drawing. The conductive composition described in Patent Document 1 still has room for improvement in terms of reducing the defect-causing component.

[0007] The present invention aims to provide a conductive composition that has good coatability and is less likely to produce foreign matter when formed into a coating film, a method for producing the same, and a water-soluble composition used in the conductive composition and a method for producing the same.

[0008] The present invention has the following aspects. [1] A water-soluble composition comprising a water-soluble polymer and satisfying the following conditions (A1) and (A2): (A1) The water-soluble polymer comprises a nitrogen-containing functional group; (A2) A 1.0% by mass aqueous solution of the water-soluble composition has a surface tension of 34.0 to 50.0 at 25°C; [2] The water-soluble composition according to [1] above, further satisfying the following condition (A3): (A3) The water-soluble composition contains a component, as quantified by the following measurement method, in an amount greater than 0 ppm by mass and not more than 1.3 ppm by mass. <Measurement Method> A sample (S1) is prepared by mixing a solution (I) obtained by dissolving ethyl n-caproate in methanol to a concentration of 5 mg / L with a solution (II) obtained by dissolving the water-soluble composition in a mixed solvent having a volume ratio of water to methanol (water / methanol) of 2 / 8 to a concentration of 0.2% by mass, in a volume ratio (solution (I) / solution (II)) of 1 / 10, and the mixture is subjected to gas chromatography analysis. After injecting the sample (S1) into a gas chromatograph, the time when the column oven is heated to 50°C is set as time 0, and the temperature is raised to 300°C at a rate of 10°C / min and held at 300°C for 10 minutes. In this 35-minute analysis, the peak area obtained between 25 and 35 minutes is quantified by comparing it with a calibration curve previously prepared using n-dodecyl mercaptan. [3] The water-soluble composition according to [1] or [2] above, further satisfying the following condition (A4): (A4) The water-soluble composition contains more than 0 ppm by mass and less than 1.0 ppm by mass of a component quantified by the following measurement method: <Measurement Method> A sample (S1) is prepared by mixing a solution (I) prepared by dissolving n-ethyl caproate in methanol to a concentration of 5 mg / L with a solution (II) prepared by dissolving the water-soluble composition in a mixed solvent having a volume ratio of water to methanol (water / methanol) of 2 / 8 to a concentration of 0.2 mass % at a volume ratio (solution (I) / solution (II)) of 1 / 10, and is subjected to gas chromatography analysis. After injecting the sample (S1) into a gas chromatograph, the column oven is heated to 50°C, and the time point is set as time 0. The temperature is then increased to 300°C at a rate of 10°C / min, and the sample is held at 300°C for 10 minutes. The peak area obtained between 25 and 35 minutes is quantified against a calibration curve previously prepared using n-dodecyl mercaptan. [4] A water-soluble composition comprising a water-soluble polymer and satisfying the following conditions (B1) to (B3):(B1) The water-soluble polymer contains a nitrogen-containing functional group. (B2) A 1.0% by mass aqueous solution of the water-soluble composition has a surface tension of 10.0 to 50.0 at 25°C. (B3) The water-soluble composition contains a component, as quantified by the following measurement method, in an amount greater than 0 ppm by mass and not more than 1.3 ppm by mass. <Measurement Method> A solution (I) obtained by dissolving ethyl n-caproate in methanol to a concentration of 5 mg / L and a solution (II) obtained by dissolving the water-soluble composition in a mixed solvent having a volume ratio of water to methanol (water / methanol) of 2 / 8 to a concentration of 0.2% by mass are mixed together in a volume ratio (solution (I) / solution (II)) of 1 / 10, and a gas chromatography analysis is performed on a sample (S1). After injecting the sample (S1) into a gas chromatograph, the time when the column oven is heated to 50°C is set as time 0, and the temperature is raised to 300°C at a rate of 10°C / min and held at 300°C for 10 minutes. In this 35-minute analysis, the peak area obtained between 25 and 35 minutes is quantified by comparing it with a calibration curve previously prepared using n-dodecyl mercaptan. [5] The water-soluble composition according to [4] above, further satisfying the following condition (B4): (B4) The water-soluble composition contains more than 0 ppm by mass and less than 1.0 ppm by mass of a component quantified by the following measurement method: <Measurement Method> A sample (S1) is prepared by mixing a solution (I) prepared by dissolving n-ethyl caproate in methanol to a concentration of 5 mg / L with a solution (II) prepared by dissolving the water-soluble composition in a mixed solvent having a volume ratio of water to methanol (water / methanol) of 2 / 8 to a concentration of 0.2 mass % at a volume ratio (solution (I) / solution (II)) of 1 / 10, and then analyzing the mixture by gas chromatography. After injecting the sample (S1) into a gas chromatograph, the column oven is heated to 50°C, and the time point is set as time 0. The temperature is then increased to 300°C at a rate of 10°C / min, and the sample is held at 300°C for 10 minutes. The peak area obtained between 25 and 35 minutes is quantified by comparing it with a calibration curve prepared in advance using n-dodecyl mercaptan. [6] The water-soluble composition according to any one of [4] and [5] above, wherein the water-soluble polymer has a mass-average molecular weight of 600 to 20,000. [7] The water-soluble composition according to any one of [1] to [6], wherein the water-soluble polymer has a nitrogen-containing functional group.[8] The water-soluble composition of any one of [1] to [7] above, wherein the water-soluble polymer contains a pyrrolidone structure. [9] A conductive composition comprising the water-soluble composition of any one of [1] to [8] above and a conductive polymer.

[10] The conductive composition of [9] above, wherein the conductive polymer contains a conductive polymer having at least one unit selected from units represented by the following general formulas (1) to (4):

[0009]

[0010]

[0011]

[0012]

[0013] In the general formulas (1) to (4), X represents a sulfur atom or a nitrogen atom, and R １ ~R １５ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group or a salt thereof, a hydroxy group, a nitro group, a halogen atom, -N(R １６ ) ２ , -NHCOR １６ , -SR １６ , -OCOR １６ , -COOR １６ , -COR １６ , —CHO, or —CN. １６ represents an alkyl group having 1 to 24 carbon atoms, an aryl group having 6 to 24 carbon atoms, or an aralkyl group having 7 to 24 carbon atoms. １ , R ２ At least one of R in general formula (2) ３ ~R ６ At least one of R in general formula (3) ７ ~R １０ At least one of R in general formula (4) １１ ~R １５

[11] The conductive composition according to [9] or

[10] , wherein the conductive polymer comprises a conductive polymer having a unit represented by the following general formula (4):

[0014]

[0015] In general formula (4), R １１ ~R １５ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group or a salt thereof, a hydroxy group, a nitro group, a halogen atom, -N(R １６ ) ２ , -NHCOR １６ , -SR １６ , -OCOR １６ , -COOR １６ , -COR １６ , —CHO, or —CN. １６represents an alkyl group having 1 to 24 carbon atoms, an aryl group having 6 to 24 carbon atoms, or an aralkyl group having 7 to 24 carbon atoms.

[12] The conductive composition according to any one of [9] to

[11] above, further comprising a basic compound.

[13] The conductive composition according to

[12] above, wherein the basic compound comprises a quaternary ammonium compound.

[14] The method for producing the water-soluble composition according to any one of [1] to [8] above, comprising a reprecipitation step of mixing a good solvent solution containing the water-soluble polymer and a good solvent for the water-soluble polymer with a poor solvent for the water-soluble polymer, wherein the poor solvent comprises an ether.

[15] The method for producing the water-soluble composition according to

[14] above, further comprising a synthesis step of the water-soluble polymer, wherein the reprecipitation step is performed after the synthesis step, and wherein the reaction solution from the synthesis step is used as the good solvent solution for the reprecipitation step.

[16] The method for producing the water-soluble composition according to

[14] or

[15] above, wherein the amount of the poor solvent mixed is 100 parts by mass or more per 100 parts by mass of the good solvent solution.

[17] The method for producing a water-soluble composition according to any one of

[14] to

[16] above, wherein the poor solvent further contains an alkane.

[18] The method for producing a water-soluble composition according to

[17] above, wherein the mass ratio of the alkane to the ether (alkane / ether) is 0.5 to 2.0.

[19] A method for producing a conductive composition, comprising: producing a water-soluble composition by the method for producing a water-soluble composition according to any one of

[14] to

[18] above, and mixing the water-soluble composition obtained in the step of producing the water-soluble composition with a conductive polymer.

[0016] According to the present invention, it is possible to provide a conductive composition that has good coatability and is less likely to generate foreign matter when formed into a coating film, a method for producing the same, and a water-soluble composition used in the conductive composition and a method for producing the same.

[0017] The present invention will be described in detail below. The following embodiments are merely examples for explaining the present invention, and are not intended to limit the present invention to these embodiments. The present invention can be implemented in various forms without departing from the spirit of the present invention.

[0018] In the present invention, "conductivity" means a value of 1×10 １１The surface resistivity is determined by the surface area (1 cm) of the test object. ２ ) is the surface resistance value per unit area. The surface resistance value is determined from the potential difference between the electrodes when a constant current is passed through them. In this specification, "solubility" means that 0.1 g or more of the compound dissolves uniformly in 10 g (liquid temperature 25°C) of one or more of the following solvents: simple water, water containing at least one of a base and a basic salt, water containing an acid, and a mixture of water and a water-soluble organic solvent. Furthermore, "water solubility" refers to solubility in water with respect to the solubility. In this specification, the "terminal" of "terminal hydrophobic group" refers to a portion other than the repeating units constituting the polymer. In this specification, the "mass average molecular weight" refers to the mass average molecular weight (in terms of sodium polystyrene sulfonate or polyethylene glycol) measured by gel permeation chromatography (GPC). In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0019] [Water-soluble composition containing a water-soluble polymer] One embodiment of the present invention is a water-soluble composition (hereinafter also referred to as "water-soluble composition (i)") that contains a water-soluble polymer and satisfies the following conditions (A1) and (A2): (A1) The water-soluble polymer contains a nitrogen-containing functional group. (A2) The surface tension of a 1.0% by mass aqueous solution of the water-soluble composition (i) at 25°C is 34.0 to 50.0.

[0020] The surface tension under condition (A2) is measured by the following method. The surface tension of the 1.0% by mass aqueous solution is a value measured by dissolving the water-soluble composition in water to a concentration of 1.0% by mass, adjusting the temperature of the resulting aqueous solution (1.0% by mass aqueous solution) to 25°C, and using an automatic surface tensiometer to measure the value by the plate method (Wilhelmy method). Specifically, a measuring probe (platinum plate) is immersed in the 1.0% by mass aqueous solution adjusted to 25°C, and the surface tension is calculated from the displacement of the measuring probe sunk into the 1.0% by mass aqueous solution when the force (surface tension) pulling the measuring probe by the 1.0% by mass aqueous solution is balanced with the force of the spring fixing the measuring probe.

[0021] The water-soluble composition (i) may be either Aspect 1 or Aspect 2 below. Aspect 1: A water-soluble composition containing a water-soluble polymer having surface activity, which satisfies the conditions (A1) and (A2). Aspect 2: A water-soluble composition containing a water-soluble polymer which satisfies the condition (A1) and a surfactant which satisfies the condition (A2).

[0022] The water-soluble composition (i) of this embodiment preferably further satisfies condition (A3), and more preferably further satisfies condition (A4). (A3) The water-soluble composition contains more than 0 ppm by mass and not more than 1.3 ppm by mass of a component (hereinafter also referred to as "component (X)") as determined by the measurement method below. (A4) The water-soluble composition contains more than 0 ppm by mass and not more than 1.0 ppm by mass of a component as determined by the measurement method below. That is, the content of component (X) in the water-soluble composition (i), as determined by the measurement method below, is preferably more than 0 ppm by mass and not more than 1.3 ppm by mass, and more preferably more than 0 ppm by mass and less than 1.0 ppm by mass, relative to the total mass of the water-soluble composition (i). <Measurement Method> A solution (I) in which n-ethyl caproate is dissolved in methanol to a concentration of 5 mg / L and a solution (II) in which water-soluble composition (i) is dissolved in a mixed solvent having a volume ratio of water to methanol (water / methanol) of 2 / 8 to a concentration of 0.2 mass% are mixed so that the volume ratio (solution (I) / solution (II)) is 1 / 10, and a gas chromatography analysis is performed on a sample (S1). After the sample (S1) is injected into a gas chromatograph, the column oven is heated to 50°C, and the time point is set as 0 minute. The temperature is then increased to 300°C at a rate of 10°C / min, and the sample is held at 300°C for 10 minutes. In a 35-minute analysis, the peak area obtained between 25 and 35 minutes is quantified by comparing it with a calibration curve previously prepared using n-dodecyl mercaptan. That is, the area of ​​the peak detected while the column oven is maintained at 300°C for 10 minutes after reaching 300°C is quantified by the internal standard method using n-dodecyl mercaptan as a standard sample and n-ethyl caproate as an internal standard substance, and the resulting value is regarded as the content (concentration) of component (X) in the surfactant. The peak area refers to the area enclosed by the baseline, which is a straight line connecting the point where the peak rises (the start point of the peak) and the point where the peak ends (the end point of the peak).

[0023] The calibration curve is prepared as follows. First, n-dodecyl mercaptan is dissolved in a mixed solvent of water and methanol in a volume ratio (water / methanol) of 2 / 8 to prepare solutions (III-1) to (III-4) (hereinafter, these may be collectively referred to as "solution (III)"). Each of solutions (III-1) to (III-4) is mixed with solution (I) in a volume ratio (solution (I) / solution (III)) of 1 / 10, and samples (S2) to (S5) are analyzed by gas chromatography. After each of the samples (S2) to (S5) is injected into a gas chromatograph, the time when the column oven is heated to 50°C is set as 0 minute, and the temperature is raised to 300°C at a rate of 10°C / min. The temperature is then maintained at 300°C for 10 minutes in a 35-minute analysis. The areas of the peaks obtained between 25 and 35 minutes are determined, and a calibration curve showing the relationship between the concentration ratio of n-dodecyl mercaptan to the internal standard substance ethyl n-caproate and the peak area ratio is prepared.

[0024] Component (X) is a defect-causing component, and is thought to be primarily a chain transfer agent remaining in the water-soluble polymer used in producing the water-soluble polymer. When the content of component (X) is equal to or less than the upper limit, the proportion of defect-causing components contained in the water-soluble composition (i) is low, and thus foreign matter is less likely to occur in a coating film formed from a conductive composition containing the water-soluble composition (i) of this embodiment. The lower the content of component (X), the lower the proportion of defect-causing components contained in the water-soluble composition (i). Therefore, the smaller the content of component (X), the better. Specifically, the content is preferably greater than 0 ppm by mass and less than 1.3 ppm by mass, more preferably greater than 0 ppm by mass and less than 1.2 ppm by mass, more preferably greater than 0 ppm by mass and less than 1.0 ppm by mass, and even more preferably greater than 0 ppm by mass and less than 0.8 ppm by mass, relative to the total mass of the water-soluble composition (i).

[0025] Another embodiment of the present invention is a water-soluble composition (hereinafter also referred to as "water-soluble composition (ii)") that contains a water-soluble polymer and satisfies the following (B1) to (B3): (B1) The water-soluble polymer contains a nitrogen-containing functional group. (B2) A 1.0 mass% aqueous solution of the water-soluble composition (ii) has a surface tension of 10.0 to 50.0 at 25°C. (B3) The water-soluble composition (ii) contains component (X) in an amount of more than 0 ppm by mass and not more than 1.3 ppm by mass. The method for measuring the surface tension in the condition (B2) and the method for measuring the content of the quantitative component in the condition (B3) are the same as the method for measuring the surface tension in the condition (A2) and the method for measuring the content of the component (X) in the condition (A3), except that the object of measurement is the water-soluble composition (ii).

[0026] The water-soluble composition (ii) may be either Aspect 1 or Aspect 2 below. Aspect 1: A water-soluble composition containing a water-soluble polymer having surface activity, which satisfies the conditions (B1) and (B2). Aspect 2: A water-soluble composition containing a water-soluble polymer which satisfies the condition (B1) and a surfactant which satisfies the condition (B2).

[0027] The component (X) in the condition (B3) is a defect-causing component, and is thought to be primarily a chain transfer agent remaining in the water-soluble polymer used in producing the water-soluble polymer. When the content of component (X) is equal to or less than the upper limit, the proportion of defect-causing components contained in the water-soluble composition (ii) is low, and therefore foreign matter is less likely to occur in a coating film formed from a conductive composition containing the water-soluble composition (ii) of this embodiment. The lower the content of component (X), the lower the proportion of defect-causing components contained in the water-soluble composition. Therefore, the smaller the content of component (X), the better. Specifically, the content is preferably greater than 0 ppm by mass and not more than 1.3 ppm by mass, more preferably greater than 0 ppm by mass and not more than 1.2 ppm by mass, more preferably greater than 0 ppm by mass and not more than 1.0 ppm by mass, and even more preferably greater than 0 ppm by mass and not more than 0.8 ppm by mass, relative to the total mass of the water-soluble composition (ii).

[0028] As the water-soluble polymer, a compound having a main chain structure of a homopolymer of a vinyl monomer having a nitrogen-containing functional group, or a copolymer of a vinyl monomer having a nitrogen-containing functional group and a vinyl monomer (other vinyl monomer) not having a nitrogen-containing functional group, and having a hydrophobic group at a site other than the repeating units constituting the polymer, is preferred. Among them, a compound containing a pyrrolidone structure, i.e., a compound containing a unit derived from pyrrolidone, is particularly preferred. Examples of the nitrogen-containing functional group include an amide group, an imide group, an amino group, a group derived from an aromatic heterocyclic structure, a group derived from a non-aromatic heterocyclic structure, and a cyano group. Among these, an amide group is preferred from the viewpoint of solubility. The amide group may be cyclic.

[0029] Examples of vinyl monomers having a nitrogen-containing functional group include acrylamide and its derivatives, heterocyclic monomers having a nitrogen-containing functional group, and the like, with those having an amide bond being preferred. Specific examples include acrylamide, N,N-dimethylacrylamide, N-isopropylacrylamide, N,N-diethylacrylamide, N,N-dimethylaminopropylacrylamide, t-butylacrylamide, diacetoneacrylamide, N,N'-methylenebisacrylamide, N-vinyl-N-methylacrylamide, N-vinylpyrrolidone, N-vinylcaprolactam, and the like. Among these, from the viewpoint of solubility, acrylamide, N-vinylpyrrolidone, N-vinylcaprolactam, and the like are preferred, with N-vinylpyrrolidone being particularly preferred. Other vinyl monomers are not particularly limited as long as they are copolymerizable with a vinyl monomer having a nitrogen-containing functional group, and examples include styrene, acrylic acid, vinyl acetate, and long-chain α-olefins. These water-soluble polymers may be used alone or in combination of two or more in any desired ratio.

[0030] The main chain portion of the water-soluble polymer is water-soluble and has a nitrogen-containing functional group. The number of units (degree of polymerization) in the main chain portion per molecule is preferably 2 to 1,000, more preferably 2 to 100, and particularly preferably 2 to 50. By setting the number of units in the main chain portion having a nitrogen-containing functional group within this range, it becomes easier to control the surface activity.

[0031] The weight average molecular weight of the water-soluble polymer, as calculated by GPC equivalent polyethylene glycol, is preferably 600 or more, more preferably 1,000 or more, even more preferably 1,500 or more, and preferably 1,000,000 or less, more preferably 100,000 or less, even more preferably 20,000 or less, particularly preferably 10,000 or less, particularly preferably less than 2,000, and most preferably 1,800 or less. The lower and upper limits of the weight average molecular weight of the water-soluble polymer can be arbitrarily combined; for example, 600 to 1,000,000 is preferred, 600 to 100,000 is more preferred, 600 to 20,000 is even more preferred, 600 to 10,000 or less is particularly preferred, 600 to 2,000 is particularly preferred, and 600 to 1,800 is most preferred. If the weight average molecular weight of the water-soluble polymer is equal to or greater than the lower limit, the coatability of the conductive composition is improved. On the other hand, if the weight average molecular weight of the water-soluble polymer is equal to or less than the upper limit, the water solubility of the conductive composition is improved. In particular, when the mass average molecular weight of the water-soluble polymer is 600 or more and 10,000 or less, a good balance between practical solubility in water and coatability is achieved.

[0032] The surfactant is not particularly limited as long as the content of component (X) in the water-soluble composition is within the above-mentioned range, and examples thereof include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. The molecular weight of the surfactant is preferably 2000 or less, more preferably 1000 or less, and even more preferably less than 600. The molecular weight of the surfactant is preferably 50 or more, and more preferably 100 or more. The lower and upper limits of the molecular weight of the surfactant can be arbitrarily combined, and for example, are preferably 50 or more and 2000 or less, more preferably 50 or more and 1000 or less, and even more preferably 100 or more and less than 600. The surface tension of a 1.0% by mass aqueous solution of the surfactant at 25°C is preferably 10 or more, more preferably 20 or more, even more preferably 30 or more, and particularly preferably 35 or more. The surface tension of a 1.0% by mass aqueous solution of the surfactant at 25°C is preferably 50 or less, more preferably 45 or less, and even more preferably 40 or less. The surface tension of the surfactants can be arbitrarily combined, and is, for example, preferably 10 to 50, more preferably 20 to 50, even more preferably 30 to 45, and particularly preferably 35 to 40. Any one of these surfactants may be used alone, or two or more types may be mixed in any ratio.

[0033] Examples of anionic surfactants include sodium dialkyl sulfosuccinate, sodium octanoate, sodium decanoate, sodium laurate, sodium myristate, sodium palmitate, sodium stearate, perfluorononanoic acid, sodium N-lauroyl sarcosinate, sodium cocoyl glutamate, alpha sulfo fatty acid methyl ester salts, sodium lauryl sulfate, sodium myristyl sulfate, sodium laureth sulfate, sodium polyoxyethylene alkylphenol sulfonate, ammonium lauryl sulfate, lauryl phosphoric acid, sodium lauryl phosphate, and potassium lauryl phosphate.

[0034] Examples of cationic surfactants include tetramethylammonium chloride, tetramethylammonium hydroxide, tetrabutylammonium chloride, dodecyldimethylbenzylammonium chloride, alkyltrimethylammonium chloride, octyltrimethylammonium chloride, decyltrimethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, alkyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzalkonium chloride, benzalkonium bromide, benzethonium chloride, dialkyldimethylammonium chloride, didecyldimethylammonium chloride, distearyldimethylammonium chloride, monomethylamine hydrochloride, dimethylamine hydrochloride, trimethylamine hydrochloride, butylpyridinium chloride, dodecylpyridinium chloride, and cetylpyridinium chloride.

[0035] Examples of amphoteric surfactants include lauryl dimethylamino acetic acid betaine, stearyl dimethylamino acetic acid betaine, dodecyl aminomethyl dimethyl sulfopropyl betaine, octadecyl aminomethyl dimethyl sulfopropyl betaine, cocamidopropyl betaine, cocamidopropyl hydroxysultaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, sodium lauroyl glutamate, potassium lauroyl glutamate, lauroyl methyl-β-alanine, lauryl dimethylamine-N-oxide, and oleyl dimethylamine N-oxide.

[0036] Examples of nonionic surfactants include glyceryl laurate, glyceryl monostearate, sorbitan fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkyl ethers, pentaethylene glycol monododecyl ether, octaethylene glycol monododecyl ether, polyoxyethylene alkylphenyl ethers, octylphenol ethoxylate, nonylphenol ethoxylate, polyoxyethylene polyoxypropylene glycol, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene hexitane fatty acid esters, sorbitan fatty acid ester polyethylene glycol, lauric acid diethanolamide, oleic acid diethanolamide, stearic acid diethanolamide, octyl glucoside, decyl glucoside, lauryl glucoside, cetanol, stearyl alcohol, and oleyl alcohol.

[0037] In addition to the above, a water-soluble polymer having surface activity may also be used as the nonionic surfactant. As in Aspect 1, from the viewpoint of improving coatability, the water-soluble polymer having surface activity preferably has a nitrogen-containing functional group and further has a terminal hydrophobic group. Unlike conventional surfactants, a water-soluble polymer having a nitrogen-containing functional group and a terminal hydrophobic group can have surface activity due to the main chain portion (hydrophilic portion) having the nitrogen-containing functional group and the terminal hydrophobic group portion, and is particularly effective in improving coatability.

[0038] Examples of terminal hydrophobic groups include alkyl groups, aralkyl groups, aryl groups, alkoxy groups, aralkyloxy groups, aryloxy groups, alkylthio groups, aralkylthio groups, arylthio groups, primary or secondary alkylamino groups, aralkylamino groups, and arylamino groups. Among these, alkylthio groups, aralkylthio groups, and arylthio groups are preferred. The number of carbon atoms in the terminal hydrophobic group is preferably 7 to 100, more preferably 7 to 50, and particularly preferably 10 to 30. The number of terminal hydrophobic groups in the water-soluble polymer is not particularly limited. Furthermore, when two or more terminal hydrophobic groups are present in the same molecule, the terminal hydrophobic groups may be the same or different types.

[0039] The method for introducing a terminal hydrophobic group into a water-soluble polymer is not particularly limited, but is typically preferred as it is simple and easy to introduce by selecting a chain transfer agent during vinyl polymerization. In this case, the chain transfer agent is not particularly limited as long as it introduces a group containing a hydrophobic group, such as an alkyl group, an aralkyl group, an aryl group, an alkylthio group, an aralkylthio group, or an arylthio group, into the terminal of the resulting polymer. For example, when obtaining a water-soluble polymer having an alkylthio group, an aralkylthio group, or an arylthio group as the terminal hydrophobic group, it is preferable to carry out vinyl polymerization using a chain transfer agent having a hydrophobic group corresponding to the terminal hydrophobic group, specifically a thiol, a disulfide, a thioether, or the like. Examples of such chain transfer agents include n-dodecyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan, 2-ethylhexyl mercaptan, and n-octadecyl mercaptan. These may be used alone or in combination of two or more.

[0040] The polymerization initiator used in vinyl polymerization may be azobismethylbutyronitrile or a polymerization initiator having a terminal hydrophobic group. Examples of the polymerization initiator having a terminal hydrophobic group include those having a linear or branched alkyl group having 6 to 20 carbon atoms and not having a cyano group or a hydroxy group, and specific examples include dilauroyl peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-hexyl peroxide, di(2-ethylhexyl)peroxydicarbonate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, and di(3,5,5-trimethylhexanoyl)peroxide. These may be used alone or in combination of two or more.

[0041] The molecular weight ratio (weight average molecular weight of main chain portion / weight average molecular weight of terminal hydrophobic group portion) of the water-soluble polymer to the main chain portion (e.g., alkyl group, aralkyl group, aryl group, alkylthio group, aralkylthio group, arylthio group, etc.) is preferably 0.3 to 170.

[0042] The surface tension of a 1.0 mass % aqueous solution of the water-soluble composition containing the water-soluble polymer having surfactant properties in Aspect 1 and the water-soluble composition containing the water-soluble polymer and surfactant in Aspect 2 at 25°C is preferably 10 or more, more preferably 20 or more, even more preferably 30 or more, and particularly preferably 35 or more. The surface tension of a 1.0 mass % aqueous solution of the water-soluble polymer having surfactant properties at 25°C is preferably 50 or less, more preferably 45 or less, and even more preferably 40 or less. The lower and upper limits of the surface tension can be arbitrarily combined; for example, 10 to 50 is preferred, 20 to 50 is more preferred, 30 to 45 is even more preferred, and 35 to 40 is particularly preferred.

[0043] When a water-soluble polymer and a surfactant are used in combination as in Aspect 2, the water-soluble polymer may be a water-soluble polymer having the above-mentioned surface activity, or a water-soluble polymer having a surface tension of more than 50 in a 1.0% by mass aqueous solution at 25°C. Examples of water-soluble polymers having a surface tension of more than 50 in a 1.0% by mass aqueous solution at 25°C include water-soluble polymers having a nitrogen-containing functional group and no terminal hydrophobic group.

[0044] Among the surfactants mentioned above, nonionic surfactants are preferred because they have little effect on the resist layer, and among these, water-soluble polymers having a nitrogen-containing functional group are particularly preferred, with water-soluble polymers having a nitrogen-containing functional group and a terminal hydrophobic group being more preferred. Among the water-soluble polymers, compounds represented by the following general formula (7) (hereinafter also referred to as "compound (7)") and compounds represented by the following general formula (8) (hereinafter also referred to as "compound (8)") are particularly preferred. Any one of these compounds may be used alone, or two or more may be mixed in any ratio.

[0045]

[0046] In formula (7), R ３８ represents a hydrogen atom, a linear or branched alkyl group, an aralkyl group, or an aryl group; R ３９ represents a hydrogen atom, an alkylthio group, an aralkylthio group, an arylthio group, or a hydrocarbon group; R ４０represents a hydrophilic group, R ４１ represents a hydrogen atom or a methyl group, Z1 represents a single bond, -S-, -S(=O)-, -C(=O)-O- or -O-, and p is a number from 1 to 50. ３８ and R ３９ are never simultaneously hydrogen atoms.

[0047]

[0048] In formula (8), R ４２ and R ４３ each independently represents a methyl group or an ethyl group, R ４４ represents a hydrogen atom, an alkylthio group, an aralkylthio group, an arylthio group, or a hydrocarbon group; R ４５ represents a hydrophilic group, R ４６ represents a hydrogen atom or a methyl group, Z ２ represents a cyano group or a hydroxy group, and q is a number from 1 to 50.

[0049] R ３８ The alkyl group in R preferably has 6 to 20 carbon atoms. ３８ The aralkyl group in R preferably has 7 to 20 carbon atoms. ３８ The number of carbon atoms of the aryl group in R is preferably 6 to 20. ３９ , R ４４ The alkylthio group in R may be a group in which a sulfur atom is bonded to a linear or branched alkyl group having 1 to 20 carbon atoms. ３９ , R ４４ The aralkylthio group in the formula (R) includes a group in which a sulfur atom is bonded to a linear or branched aralkyl group having 7 to 20 carbon atoms. ３９ , R ４４ The aryl group in R may be a straight or branched chain aryl group having 6 to 20 carbon atoms to which a sulfur atom is bonded. ３９ , R ４４ Examples of the hydrocarbon group in R include a linear or branched alkyl group having 1 to 20 carbon atoms, a linear or branched alkenyl group having 1 to 20 carbon atoms, and a linear or branched alkynyl group having 1 to 20 carbon atoms. ４０ , R ４５The hydrophilic group in the above is derived from a water-soluble vinyl monomer, which is a raw material monomer for the water-soluble polymer. Here, the water-soluble vinyl monomer refers to a vinyl monomer that can be mixed with water in any ratio. Examples of such water-soluble vinyl monomers include N-vinylpyrrolidone, 2-hydroxyethyl (meth)acrylate, (meth)acrylamide, N,N-dimethylacrylamide, acryloylmorpholine, and N-vinylformamide.

[0050] Examples of compound (7) include a compound represented by the following general formula (71) (hereinafter also referred to as "compound (71)").

[0051]

[0052] In formula (71), R ３８ represents a hydrogen atom, a linear or branched alkyl group, an aralkyl group, or an aryl group; R ３９ represents a hydrogen atom, an alkylthio group, an aralkylthio group, an arylthio group or a hydrocarbon group; Z １ represents a single bond, -S-, -S(=O)-, -C(=O)-O- or -O-, p is a number from 1 to 50, and r is a number from 1 to 5. ３８ and R ３９ are never simultaneously hydrogen atoms.

[0053] Examples of compound (8) include a compound represented by the following general formula (81) (hereinafter also referred to as "compound (81)").

[0054]

[0055] In formula (81), R ４２ and R ４３ each independently represents a methyl group or an ethyl group, R ４４ represents a hydrogen atom, an alkylthio group, an aralkylthio group, an arylthio group or a hydrocarbon group; Z ２ represents a cyano group or a hydroxy group, q is a number from 1 to 50, and s is a number from 1 to 5.

[0056] <Method for Producing a Water-Soluble Composition> One embodiment of the present invention is a method for producing a water-soluble composition. The production method described below is preferably used for producing a water-soluble composition containing a water-soluble polymer having a nitrogen-containing functional group. A water-soluble composition having a content of component (X) within the above range can be obtained by purifying a water-soluble polymer. Methods for purifying water-soluble polymers include reprecipitation, membrane filtration using a filter, ion exchange, washing with a solvent, recrystallization, and liquid-liquid separation and extraction. Among these, reprecipitation is particularly preferred for purifying surfactants. The reprecipitation method involves dissolving the target to be purified in a good solvent in which the target has high solubility to prepare a good solvent solution, and then mixing this good solvent solution with a poor solvent in which the target has low solubility to purify the target to be purified. Two or more of these methods may also be combined to purify the water-soluble polymer. An example of a method for producing a water-soluble polymer using the reprecipitation method is described below.

[0057] The method for producing a water-soluble composition according to this embodiment includes a reprecipitation step in which a good solvent solution containing a water-soluble polymer is mixed with an ether. Specifically, a good solvent solution is prepared by dissolving the water-soluble polymer in a good solvent, and the good solvent solution is mixed with a poor solvent to purify the water-soluble polymer. The good solvent used in the good solvent solution is not particularly limited as long as it is a solvent that highly dissolves the water-soluble polymer. Examples of good solvents for water-soluble polymers include alcohols such as methanol, ethanol, isopropyl alcohol, propyl alcohol, and butanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and propylene glycol monomethyl ether acetate; esters such as ethyl acetate and butyl acetate; nitriles such as acetonitrile; alkyl halides such as chloroform and dichloromethane; aromatics such as toluene and benzene; nitrogen-containing solvents such as dimethylformamide and N-methyl-2-pyrrolidone; and sulfur-containing solvents such as dimethyl sulfoxide. Among these, alcohols are preferred in terms of their high polarity and ease of removal due to their low boiling point. These good solvents may be used alone or in combination of two or more in any proportion. The phrase "high solubility of a water-soluble polymer" means that 0.1 g or more of the water-soluble polymer is uniformly dissolved in 10 g of the solvent (liquid temperature: 25° C.).

[0058] The poor solvent is not particularly limited as long as it is a solvent that has low solubility for the water-soluble polymer. As the poor solvent for the water-soluble polymer, ether is preferred from the viewpoint of increasing purification efficiency, and it is more preferred to use an ether and an alkane in combination. That is, in the reprecipitation step, it is preferred to mix a good solvent solution with an ether, and it is more preferred to mix a good solvent solution with an ether and an alkane. Note that "low solubility for the water-soluble polymer" means that the amount dissolved in 10 g of solvent (liquid temperature 25°C) is less than 0.1 g.

[0059] Ethers are solvents in which two carbon atoms are bonded to one oxygen atom. Examples of ethers include diethyl ether, diisopropyl ether, t-butyl methyl ether, methoxycyclopentaene, and dibutyl ether. Among these, diethyl ether, diisopropyl ether, and t-butyl methyl ether are preferred from the viewpoints of low polarity and ease of removal due to their low boiling points. Any one of these ethers may be used alone, or two or more may be mixed in any ratio.

[0060] Alkanes are solvents made of linear or branched saturated hydrocarbons. Examples of alkanes include pentane, hexane, heptane, cyclopentane, methylcyclohexane, octane, nonane, decane, undecane, and dodecane. Among these, alkanes having 1 to 20 carbon atoms are preferred from the viewpoint of improving purification efficiency, and among these, alkanes having 5 to 10 carbon atoms are more preferred, and hexane is even more preferred, from the viewpoint of ease of removal due to low polarity and low boiling point. Any one of these alkanes may be used alone, or two or more may be mixed in any ratio.

[0061] The content of the water-soluble polymer relative to the total mass of the good solvent solution is preferably 40 to 80% by mass, more preferably 50 to 75% by mass, and even more preferably 55 to 70% by mass. The amount of the poor solvent mixed is preferably 100 parts by mass or more, more preferably 500 parts by mass or more, and even more preferably 1,000 parts by mass or more, and is preferably 10,000 parts by mass or less, more preferably 8,000 parts by mass or less, and even more preferably 7,000 parts by mass or less, relative to 100 parts by mass of the good solvent solution. The lower and upper limits of the amount of the poor solvent mixed can be arbitrarily combined; for example, 100 to 10,000 parts by mass is more preferable, 500 to 8,000 parts by mass is more preferable, and 1,000 to 7,000 parts by mass is most preferable. When the amount of the poor solvent mixed is equal to or greater than the lower limit, the yield of the water-soluble polymer is increased. When the amount of the poor solvent mixed is equal to or less than the upper limit, the purification efficiency is further increased.

[0062] When an ether and an alkane are used in combination as a poor solvent, the mass ratio of the alkane to the ether (alkane / ether) is preferably 0.5 or more, more preferably 0.7 or more, even more preferably 0.8 or more, and preferably 2.0 or less, more preferably 1.6 or less, and even more preferably 1.4 or less. The lower and upper limits of the alkane / ether ratio can be arbitrarily combined, and for example, a range of 0.5 to 2.0 is preferred, 0.7 to 1.6 is more preferred, and 0.8 to 1.4 is more preferred. When the alkane / ether ratio is equal to or greater than the lower limit, the yield is easily improved. When the alkane / ether ratio is equal to or less than the upper limit, defect-causing components are easily removed.

[0063] By mixing the good solvent solution with the poor solvent, the water-soluble polymer in the good solvent solution precipitates. By filtering off the precipitate, the surfactant is obtained in the form of a wet powder. By drying the wet powder, a dry powder of the water-soluble polymer is obtained. In this way, a water-soluble polymer is obtained from which impurities such as component (X) have been sufficiently removed.

[0064] The reprecipitation step may be carried out once or twice or more times. In particular, when component (X) cannot be sufficiently removed by a single reprecipitation step, the reprecipitation step is repeated until the content of component (X) in the water-soluble polymer falls within the above-mentioned range. When the reprecipitation step is carried out twice or more times, the wet powder obtained in the immediately preceding reprecipitation step is dissolved again in a good solvent to prepare a good solvent solution, this good solvent solution is mixed with a poor solvent, and the obtained precipitate is separated by filtration, and this procedure is repeated.

[0065] The method for producing the water-soluble composition of this embodiment may further include a step of synthesizing a water-soluble polymer before the reprecipitation step, and the reaction solution obtained in the synthesis step may be used as a good solvent solution in the reprecipitation step. That is, the water-soluble polymer may be synthesized by polymerization using a solvent exemplified above as the good solvent, and in the reprecipitation step, the reaction solution after the synthesis of the water-soluble polymer may be mixed with a poor solvent to perform reprecipitation purification.

[0066] <Effects> The water-soluble composition containing the water-soluble polymer of the present embodiment described above satisfies the conditions (A1) and (A2) or satisfies the conditions (B1) to (B3), and therefore the defect-causing components are sufficiently reduced. Therefore, by using the water-soluble composition of the present embodiment, a conductive composition can be obtained that has good coatability and is less likely to generate foreign matter when formed into a coating film.

[0067] [Conductive Composition] One embodiment of the present invention is a conductive composition. The conductive composition of this embodiment is a composition containing a conductive polymer (A) shown below and the water-soluble composition of the present invention described above (hereinafter also referred to as "water-soluble composition (C)"). In addition to the conductive polymer (A) and the water-soluble composition (C), the conductive composition may further contain at least one selected from a basic compound (B) and a solvent (D) shown below. The conductive composition may also contain components (optional components) other than the conductive polymer (A), the basic compound (B), the water-soluble composition (C), and the solvent (D). In this embodiment, the surface tension of a 1.0 mass% aqueous solution at 25°C, which is the condition (A2) and (B2) satisfied by the water-soluble composition, is applied as the condition satisfied by the conductive composition. In this embodiment, the contents of specific components, which are the conditions (A3), (A4), (B3), and (B4) satisfied by the water-soluble composition, are applied as the condition satisfied by the conductive composition.

[0068] <Conductive Polymer (A)> Known conductive polymers can be used as the conductive polymer (A), and examples thereof include polythiophene, polythiophene vinylene, poly(3-alkylthiophene), poly(3,4-ethylenedioxy)thiophene (PEDOT), poly3,4ethylenedioxythiophene-polystyrene sulfonic acid (PEDOT-PSS), polyaniline, polypyrrole, polytellurophene, polyparaphenylene, polyparaphenylene vinylene, polyacene, and polyacetylene.

[0069] The conductive polymer (A) is preferably water-soluble or water-dispersible. When the conductive polymer (A) is water-soluble or water-dispersible, the coating property of the conductive composition is improved, and a conductive film of uniform thickness is easily obtained. The conductive polymer (A) preferably has an acidic group or a salt thereof. When the conductive polymer (A) has an acidic group or a salt thereof, the water solubility of the conductive polymer (A) is increased. The conductive polymer (A) may have two types of acidic groups in one molecule. Some or all of the acidic groups may form salts.

[0070] Examples of the conductive polymer (A) having an acidic group or a salt thereof include those described in JP-A-61-197633, JP-A-63-39916, JP-A-1-301714, JP-A-5-504153, JP-A-5-503953, JP-A-4-32848, JP-A-4-328181, JP-A-6-145386, JP-A-6-56987, and JP-A-5-226238. Conductive polymers such as those disclosed in JP-A-5-178989, JP-A-6-293828, JP-A-7-118524, JP-A-6-32845, JP-A-6-87949, JP-A-6-256516, JP-A-7-41756, JP-A-7-48436, JP-A-4-268331, and JP-A-2014-65898 are preferred from the viewpoint of solubility.

[0071] Specific examples of the conductive polymer (A) include π-conjugated conductive polymers containing, as a repeating unit, at least one selected from the group consisting of phenylenevinylene, vinylene, thienylene, pyrrolylene, phenylene, iminophenylene, isothianaphthene, furylene, and carbazolylene, substituted at the α- or β-position with at least one group selected from the group consisting of a sulfonic acid group and a carboxy group. When the π-conjugated conductive polymer contains at least one repeating unit selected from the group consisting of iminophenylene and carbazolylene, examples of the conductive polymer include a conductive polymer having an acidic group or a salt thereof on the nitrogen atom of the repeating unit, or a conductive polymer having an alkyl group substituted with an acidic group or a salt thereof or an alkyl group containing an ether bond on the nitrogen atom. Among these, from the viewpoint of conductivity and solubility, a conductive polymer having, as a monomer unit, at least one selected from the group consisting of thienylene, pyrrolylene, iminophenylene, phenylenevinylene, carbazolylene, and isothianaphthene, each of which has an acidic group or a salt thereof substituted at the β-position, is preferably used.

[0072] Among the above, polyaniline having an acidic group or a salt thereof, PEDOT, PEDOT-PSS, polypyrrole, and polythiophene are preferred as the conductive polymer (A) from the viewpoint of excellent conductivity. Among these, polyaniline having an acidic group or a salt thereof is particularly suitable as the conductive polymer because it is a compound with excellent solubility in water.

[0073] Examples of polyanilines having an acidic group or a salt thereof include unsubstituted or substituted polyanilines, and polymers having an acidic group or a salt thereof on the backbone of a π-conjugated polymer or on a nitrogen atom in the π-conjugated polymer, such as polydiaminoanthraquinone. Among these, from the viewpoint of exhibiting high conductivity and solubility, conductive polymers having at least one unit selected from units represented by the following general formulas (1) to (4) are preferred, and conductive polymers containing 20 to 100 mol % of this unit based on all units (100 mol %) constituting the conductive polymer are more preferred.

[0074]

[0075]

[0076]

[0077]

[0078] In the general formulas (1) to (4), X represents a sulfur atom or a nitrogen atom, and R １ ~R １５ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group or a salt thereof, a hydroxy group, a nitro group, a halogen atom (-F, -Cl, -Br or -I), -N(R １６ ) ２ , -NHCOR １６ , -SR １６ , -OCOR １６ , -COOR １６ , —COR16, —CHO, or —CN. １６ represents an alkyl group having 1 to 24 carbon atoms, an aryl group having 6 to 24 carbon atoms, or an aralkyl group having 7 to 24 carbon atoms. １ , R ２ At least one of R in general formula (2) ３ ~R ６ At least one of R in general formula (3) ７ ~R １０ At least one of R in general formula (4) １１ ~R １５ At least one of the groups is preferably an acidic group or a salt thereof.

[0079] Here, the term "acidic group" refers to a sulfonic acid group (sulfo group) or a carboxylic acid group (carboxy group). A sulfonic acid group is a group in an acid state (-SO ３ H), and may be contained in an ionic state (-SO ３ Furthermore, the sulfonic acid group may be contained in a substituent (-R １７ SO ３On the other hand, the carboxylic acid group may be contained in an acid state (-COOH) or an ionic state (-COO-). Furthermore, the carboxylic acid group may contain a substituent (-R １７ COOH). １７ represents a linear or branched alkylene group having 1 to 24 carbon atoms, a linear or branched arylene group having 6 to 24 carbon atoms, or a linear or branched aralkylene group having 7 to 24 carbon atoms. The acidic group is preferably a sulfonic acid group.

[0080] Salts of acidic groups include alkali metal salts, alkaline earth metal salts, ammonium salts, and substituted ammonium salts of sulfonic acid or carboxylic acid groups. Examples of alkali metal salts include lithium sulfate, lithium carbonate, lithium hydroxide, sodium sulfate, sodium carbonate, sodium hydroxide, potassium sulfate, potassium carbonate, potassium hydroxide, and derivatives having these skeletons. Examples of alkaline earth metal salts include magnesium salts and calcium salts. Examples of substituted ammonium salts include aliphatic ammonium salts, saturated alicyclic ammonium salts, and unsaturated alicyclic ammonium salts. Examples of aliphatic ammonium salts include methylammonium, dimethylammonium, trimethylammonium, ethylammonium, diethylammonium, triethylammonium, methylethylammonium, diethylmethylammonium, dimethylethylammonium, propylammonium, dipropylammonium, isopropylammonium, diisopropylammonium, butylammonium, dibutylammonium, methylpropylammonium, ethylpropylammonium, methylisopropylammonium, ethylisopropylammonium, methylbutylammonium, ethylbutylammonium, tetramethylammonium, tetramethylolammonium, tetraethylammonium, tetra-n-butylammonium, tetra-sec-butylammonium, and tetra-t-butylammonium. Examples of saturated alicyclic ammonium salts include piperidinium, pyrrolidinium, morpholinium, piperazinium, and derivatives having these skeletons. Examples of unsaturated alicyclic ammonium salts include pyridinium, α-picolinium, β-picolinium, γ-picolinium, quinolinium, isoquinolinium, pyrrolinium, and derivatives having these skeletons.

[0081] The conductive polymer (A) preferably has a unit represented by the general formula (4) from the viewpoint of being able to exhibit high conductivity, and more preferably has a unit represented by the following general formula (5) from the viewpoint of being particularly excellent in solubility.

[0082]

[0083] In general formula (5), R １８ ~R ２１ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group or a salt thereof, a hydroxy group, a nitro group, or a halogen atom (-F, -Cl, -Br, or -I). １８ ~R ２１ At least one of the groups is an acidic group or a salt thereof.

[0084] As the unit represented by the general formula (5), R １８ ~R ２１ Among these, it is preferable that one of them is a linear or branched alkoxy group having 1 to 4 carbon atoms, the other is a sulfonic acid group or a salt thereof, and the remaining is a hydrogen atom.

[0085] From the viewpoint of excellent solubility in water and organic solvents regardless of pH, the conductive polymer (A) preferably contains 10 to 100 mol %, more preferably 50 to 100 mol %, and particularly preferably 100 mol % of units represented by general formula (5) of all units (100 mol %) constituting the conductive polymer (A). Furthermore, from the viewpoint of excellent conductivity, the conductive polymer (A) preferably contains 10 or more units represented by general formula (5) per molecule.

[0086] From the viewpoint of further improving the solubility of the conductive polymer (A), the number of aromatic rings to which an acidic group or a salt thereof is bonded relative to the total number of aromatic rings in the polymer is preferably 50% or more, more preferably 70% or more, even more preferably 80% or more, particularly preferably 90% or more, and most preferably 100%. The number of aromatic rings to which an acidic group or a salt thereof is bonded relative to the total number of aromatic rings in the polymer refers to a value calculated from the monomer charging ratio during the production of the conductive polymer (A).

[0087] In the conductive polymer (A), the substituent other than the acidic group or a salt thereof on the aromatic ring of the monomer unit is preferably an electron-donating group from the viewpoint of imparting reactivity to the monomer. Specifically, an alkyl group having 1 to 24 carbon atoms, an alkoxy group having 1 to 24 carbon atoms, a halogen group (-F, -Cl, -Br, or -I), or the like is preferred, and among these, an alkoxy group having 1 to 24 carbon atoms is most preferred from the viewpoint of electron-donating properties.

[0088] Furthermore, the conductive polymer (A) may contain, as a structural unit other than the unit represented by the general formula (5), one or more units selected from the group consisting of substituted or unsubstituted aniline, thiophene, pyrrole, phenylene, vinylene, divalent unsaturated groups, and divalent saturated groups, as long as the solubility, conductivity, and properties are not affected.

[0089] As the conductive polymer (A), from the viewpoint of being able to exhibit high conductivity and solubility, a compound having a structure represented by the following general formula (6) is preferred, and among the compounds having a structure represented by the following general formula (6), poly(2-sulfo-5-methoxy-1,4-iminophenylene) and poly(2-methoxyaniline-5-sulfonic acid) are particularly preferred from the viewpoint of being particularly excellent in solubility.

[0090]

[0091] In general formula (6), R ２２ ~R ３７ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, a linear or branched alkoxy group having 1 to 4 carbon atoms, an acidic group or a salt thereof, a hydroxy group, a nitro group, or a halogen atom (-F, -Cl, -Br, or -I). ２２ ~R ３７ At least one of the groups is an acidic group or a salt thereof. Furthermore, n represents the degree of polymerization. In the present invention, n is preferably an integer of 5 to 2,500.

[0092] As the unit represented by the general formula (6), R ２２ ~R ２５one of which is a linear or branched alkoxy group having 1 to 4 carbon atoms, one of which is a sulfonic acid group or a salt thereof, and the remaining are hydrogen atoms; ２６ ~R ２９ one of which is a linear or branched alkoxy group having 1 to 4 carbon atoms, one of which is a sulfonic acid group or a salt thereof, and the remaining are hydrogen atoms; ３０ ~R ３３ one of which is a linear or branched alkoxy group having 1 to 4 carbon atoms, one of which is a sulfonic acid group or a salt thereof, and the remaining are hydrogen atoms; ３４ ~R ３７ Among these, it is preferable that one of them is a linear or branched alkoxy group having 1 to 4 carbon atoms, the other is a sulfonic acid group or a salt thereof, and the remaining is a hydrogen atom.

[0093] From the viewpoint of improving the conductivity, it is desirable that at least a part of the acidic groups contained in the conductive polymer (A) be in the free acid form.

[0094] The weight average molecular weight of the conductive polymer (A), as calculated by GPC equivalent of sodium polystyrene sulfonate, is preferably 1,000 or more, more preferably 1,500 or more, even more preferably 2,000 or more, and is preferably 1,000,000 or less, more preferably 800,000 or less, even more preferably 500,000 or less, and particularly preferably 100,000 or less. The lower and upper limits of the weight average molecular weight of the conductive polymer (A) can be arbitrarily combined, for example, preferably 1,000 to 1,000,000, more preferably 1,500 to 800,000, even more preferably 2,000 to 500,000, and particularly preferably 2,000 to 100,000. When the weight average molecular weight of the conductive polymer (A) is less than 1,000, the solubility is excellent, but the conductivity and film-forming properties may be insufficient. On the other hand, when the weight average molecular weight exceeds 1,000,000, the conductivity is excellent, but the solubility may be insufficient. Here, "film-forming properties" refers to the property of forming a uniform film without repelling or the like, and can be evaluated by a method such as spin coating on glass.

[0095] (Method for producing conductive polymer (A)) The conductive polymer (A) can be obtained, for example, by polymerizing raw material monomers for the conductive polymer (A) in the presence of a polymerization solvent and an oxidizing agent. An example of a method for producing the conductive polymer (A) will be described below. The method for producing the conductive polymer (A) of this embodiment includes a step of polymerizing raw material monomers for the conductive polymer (A) in the presence of a polymerization solvent and an oxidizing agent (polymerization step). The method for producing the conductive polymer (A) of this embodiment may also include a step of purifying the reaction product obtained in the polymerization step (purification step).

[0096] <<Polymerization Step>> The polymerization step is a step of polymerizing raw material monomers for the conductive polymer (A) in the presence of a polymerization solvent and an oxidizing agent. Specific examples of the raw material monomers include polymerizable monomers from which the above-mentioned monomer units are derived, specifically at least one selected from the group consisting of acidic group-substituted anilines, and their alkali metal salts, alkaline earth metal salts, ammonium salts, and substituted ammonium salts. Examples of acidic group-substituted anilines include sulfonic acid group-substituted anilines having a sulfonic acid group as the acidic group. Representative examples of sulfonic acid group-substituted anilines include aminobenzenesulfonic acids, specifically o-, m-, and p-aminobenzenesulfonic acid, aniline-2,6-disulfonic acid, aniline-2,5-disulfonic acid, aniline-3,5-disulfonic acid, aniline-2,4-disulfonic acid, and aniline-3,4-disulfonic acid are preferably used.

[0097] Examples of the sulfonic acid group-substituted aniline other than aminobenzenesulfonic acids include alkyl group-substituted aminobenzenesulfonic acids such as methylaminobenzenesulfonic acid, ethylaminobenzenesulfonic acid, n-propylaminobenzenesulfonic acid, iso-propylaminobenzenesulfonic acid, n-butylaminobenzenesulfonic acid, sec-butylaminobenzenesulfonic acid, and t-butylaminobenzenesulfonic acid; alkoxy group-substituted aminobenzenesulfonic acids such as methoxyaminobenzenesulfonic acid, ethoxyaminobenzenesulfonic acid, and propoxyaminobenzenesulfonic acid; hydroxy group-substituted aminobenzenesulfonic acids; nitro group-substituted aminobenzenesulfonic acids; and halogen-substituted aminobenzenesulfonic acids such as fluoroaminobenzenesulfonic acid, chloroaminobenzenesulfonic acid, and bromoaminobenzenesulfonic acid. Among these, alkyl group-substituted aminobenzenesulfonic acids, alkoxy group-substituted aminobenzenesulfonic acids, hydroxy group-substituted aminobenzenesulfonic acids, and halogen-substituted aminobenzenesulfonic acids are preferred in that they can produce a conductive polymer (A) that is particularly excellent in conductivity and solubility, and alkoxy group-substituted aminobenzenesulfonic acids, their alkali metal salts, ammonium salts, and substituted ammonium salts are particularly preferred in that they are easy to produce. Any one of these sulfonate group-substituted anilines may be used alone, or two or more may be mixed in any ratio.

[0098] Examples of polymerization solvents include water, organic solvents, and mixed solvents of water and organic solvents. Examples of water include tap water, ion-exchanged water, pure water, and distilled water. Examples of organic solvents include alcohols such as methanol, ethanol, isopropyl alcohol, propyl alcohol, and butanol; ketones such as acetone and ethyl isobutyl ketone; ethylene glycols such as ethylene glycol and ethylene glycol methyl ether; propylene glycols such as propylene glycol, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, and propylene glycol propyl ether; amides such as N,N-dimethylformamide and N,N-dimethylacetamide; and pyrrolidones such as N-methylpyrrolidone and N-ethylpyrrolidone. Water or a mixed solvent of water and an organic solvent is preferred as the polymerization solvent. When a mixed solvent of water and an organic solvent is used as the polymerization solvent, the mass ratio (water / organic solvent) between them is preferably 1 / 100 to 100 / 1, and more preferably 2 / 100 to 100 / 2.

[0099] The oxidizing agent is not limited as long as it has a standard electrode potential of 0.6 V or more, and examples thereof include peroxodisulfuric acid compounds such as peroxodisulfuric acid, ammonium peroxodisulfate, sodium peroxodisulfate, and potassium peroxodisulfate; hydrogen peroxide, etc. Any one of these oxidizing agents may be used alone, or two or more may be mixed in any desired ratio.

[0100] In the polymerization step, raw material monomers may be polymerized in the presence of a basic reaction aid in addition to a polymerization solvent and an oxidizing agent. Examples of basic reaction aids include inorganic bases such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; ammonia; alicyclic amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylmethylamine, ethyldimethylamine, and diethylmethylamine; cyclic saturated amines; and cyclic unsaturated amines such as pyridine, α-picoline, β-picoline, γ-picoline, and quinoline. Among these, inorganic bases, alicyclic amines, and cyclic unsaturated amines are preferred, and cyclic unsaturated amines are more preferred. These basic reaction aids may be used alone or in combination of two or more in any desired ratio.

[0101] Examples of polymerization methods include a method of dropping a raw material monomer solution into an oxidizing agent solution, a method of dropping an oxidizing agent solution into a raw material monomer solution, and a method of simultaneously dropping the raw material monomer solution and the oxidizing agent solution into a reaction vessel or the like. The raw material monomer solution may contain a basic reaction aid as necessary. The above-mentioned polymerization solvents can be used as solvents for the oxidizing agent solution and the raw material monomer solution.

[0102] The reaction temperature of the polymerization reaction is preferably 50° C. or lower, more preferably −15 to 30° C., and even more preferably −10 to 20° C. If the reaction temperature of the polymerization reaction is 50° C. or lower, particularly 30° C. or lower, it is possible to prevent the progression of side reactions and a decrease in conductivity due to changes in the redox structure of the main chain of the resulting conductive polymer (A). If the reaction temperature of the polymerization reaction is −15° C. or higher, it is possible to maintain a sufficient reaction rate and shorten the reaction time.

[0103] The polymerization step yields the conductive polymer (A) as a reaction product in a dissolved or precipitated state in the polymerization solvent. When the reaction product is dissolved in the polymerization solvent, the polymerization solvent is distilled off to obtain the reaction product. When the reaction product is precipitated in the polymerization solvent, the polymerization solvent is filtered off using a filter such as a centrifugal separator to obtain the reaction product.

[0104] The reaction product may contain low-molecular-weight components such as unreacted raw material monomers, oligomers resulting from side reactions, acidic substances (such as free acidic groups released from the conductive polymer (A) and sulfate ions which are decomposition products of the oxidizing agent), and basic substances (such as basic reaction aids and ammonium ions which are decomposition products of the oxidizing agent). These low-molecular-weight components are impurities that can inhibit conductivity. Therefore, it is preferable to purify the reaction product to remove the low-molecular-weight components.

[0105] <<Purification Step>> The purification step is a step of purifying the reaction product obtained in the polymerization step. Methods for purifying the reaction product include any method, such as washing using a washing solvent, membrane filtration, ion exchange, removal of impurities by heat treatment, and neutralization precipitation. Among these, washing and ion exchange are effective from the viewpoint of easily obtaining a highly pure conductive polymer (A). In particular, washing is preferred from the viewpoint of efficiently removing raw material monomers, oligomers, acidic substances, and the like. Ion exchange is preferred from the viewpoint of efficiently removing basic substances that exist in the form of salts with the acidic groups of the conductive polymer (A). In the purification step, washing and ion exchange may be used in combination.

[0106] Examples of the cleaning solvent include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-butanol, 3-butanol, t-butanol, 1-pentanol, 3-methyl-1-butanol, 2-pentanol, n-hexanol, 4-methyl-2-pentanol, 2-ethylbutynol, benzyl alcohol, furfuryl alcohol, and tetrahydrofurfuryl alcohol; polyhydric alcohol derivatives such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methoxymethoxyethanol, propylene glycol monoethyl ether, and glyceryl monoacetate; acetone; acetonitrile; N,N-dimethylformamide; N-methylpyrrolidone; and dimethyl sulfoxide. Among these, methanol, ethanol, isopropanol, acetone, and acetonitrile are effective.

[0107] The reaction product after washing, that is, the conductive polymer (A) after washing, is dried to obtain a solid conductive polymer (A).

[0108] Examples of ion exchange methods include column-type and batch-type treatments using ion exchange resins such as cation exchange resins and anion exchange resins; and electrodialysis. When the reaction product is dissolved in the polymerization solvent, it can be contacted with the ion exchange resin while still dissolved. When the reaction product is highly concentrated, it can be diluted with an aqueous medium. When the reaction product is precipitated in the polymerization solvent, it is preferable to filter the polymerization solvent, then dissolve the reaction product in an aqueous medium to a desired solids concentration, prepare a polymer solution, and then contact the ion exchange resin. When the washed reaction product is subjected to ion exchange treatment, it is preferable to dissolve the washed reaction product in an aqueous medium to a desired solids concentration, prepare a polymer solution, and then contact the ion exchange resin. Examples of aqueous media include those similar to the solvent (D) described below. From the viewpoints of industrial feasibility and purification efficiency, the concentration of the conductive polymer (A) in the polymer solution is preferably 0.1 to 20% by mass, more preferably 0.1 to 10% by mass.

[0109] In the case of an ion exchange method using an ion exchange resin, the amount of sample solution relative to the ion exchange resin is preferably up to 10 times, and more preferably up to 5 times, the volume of the ion exchange resin in the case of a polymer solution with a solids concentration of 5% by mass. Examples of cation exchange resins include "Amberlite IR-120B" manufactured by Organo Corporation. Examples of anion exchange resins include "Amberlite IRA410" manufactured by Organo Corporation.

[0110] The conductive polymer (A) after the ion exchange treatment is in a state of being dissolved in the polymerization solvent or aqueous medium. Therefore, a solid conductive polymer (A) can be obtained by completely removing the polymerization solvent or aqueous medium using an evaporator or the like, but the conductive polymer (A) may be used in the state of being dissolved in the polymerization solvent or aqueous medium for producing a conductive composition.

[0111] <Basic Compound (B)> In one embodiment, the conductive composition preferably contains a basic compound (B). When the conductive polymer (A) has acidic groups, if the conductive composition contains a basic compound (B), it is believed that the basic compound (B) efficiently acts on the acidic groups in the conductive polymer (A), thereby improving the stability of the conductive polymer (A). Here, "efficiently acting on the acidic groups in the conductive polymer (A)" means that stable neutralization of the conductive polymer (A) is possible, and a stable salt is formed between the acidic groups of the conductive polymer (A) and the basic compound (B). In other words, the conductive polymer (A) is neutralized with the basic compound (B). As a result, destabilization of the acidic groups of the conductive polymer (A) due to hydrolysis in the conductive composition can be suppressed, and the acidic groups are less likely to be released. In addition, the formation of a stable salt between the acidic groups of the conductive polymer (A) and the basic compound (B) can also suppress decomposition of the conductive polymer (A) itself. Furthermore, the basic compound (B) also forms a stable salt with decomposition products (e.g., sulfate ions) of the oxidizing agent used in the production of the conductive polymer (A). This can suppress the generation of acidic groups derived from the conductive polymer (A) and sulfate ions derived from the oxidizing agent in the conductive composition. This can also reduce the content of decomposition products of the conductive polymer (A) in the conductive composition. This can suppress the migration of acidic substances and the like from the conductive film to the resist layer, particularly in a pattern formation method using ionizing radiation that employs a chemically amplified resist, thereby suppressing the effects of film loss and the like of the resist layer.

[0112] The basic compound (B) is not particularly limited as long as it is a compound having basicity, and examples thereof include the following quaternary ammonium compound (b-1), basic compound (b-2), basic compound (b-3), and basic compound (b-4). Quaternary ammonium compound (b-1): A quaternary ammonium compound in which at least one of four substituents bonded to the nitrogen atom is a hydrocarbon group having one or more carbon atoms. Basic compound (b-2): A basic compound having one or more nitrogen atoms (excluding quaternary ammonium compound (b-1) and basic compound (b-3)). Basic compound (b-3): A basic compound having a basic group and two or more hydroxy groups in the same molecule and having a melting point of 30°C or higher. Basic compound (b-4): An inorganic base.

[0113] In the quaternary ammonium compound (b-1), the nitrogen atom to which the four substituents are bonded is the nitrogen atom of a quaternary ammonium ion. In the quaternary ammonium compound (b-1), examples of the hydrocarbon group bonded to the nitrogen atom of the quaternary ammonium ion include an alkyl group, an aralkyl group, and an aryl group. Examples of the quaternary ammonium compound (b-1) include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, tetrahexylammonium hydroxide, and benzyltrimethylammonium hydroxide.

[0114] Examples of the basic compound (b-2) include ammonia, pyridine, 4-dimethylaminopyridine, 4-dimethylaminomethylpyridine, 3,4-bis(dimethylamino)pyridine, picoline, triethylamine, 4-dimethylaminopyridine, 4-dimethylaminomethylpyridine, 3,4-bis(dimethylamino)pyridine, 1,5-diazabicyclo[4.3.0]-5-nonene (DBN), 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 1-(3-aminopropyl)-2-pyrrolidone, N-(3-aminopropyl)-ε-caprolactam, and derivatives thereof.

[0115] In the basic compound (b-3), examples of the basic group include basic groups defined as Arrhenius bases, Bronsted bases, Lewis bases, etc. Specific examples include ammonia, etc. The hydroxy group may be in the -OH state or may be protected with a protecting group. Examples of the protecting group include an acetyl group; silyl groups such as a trimethylsilyl group and a t-butyldimethylsilyl group; acetal-type protecting groups such as a methoxymethyl group, an ethoxymethyl group, and a methoxyethoxymethyl group; a benzoyl group; and an alkoxide group. Examples of the basic compound (b-3) include 2-amino-1,3-propanediol, tris(hydroxymethyl)aminomethane, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, 3-[N-tris(hydroxymethyl)methylamino]-2-hydroxypropanesulfonic acid, and N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid.

[0116] Examples of the basic compound (b-4) include sodium hydroxide, potassium hydroxide, and lithium hydroxide.

[0117] These basic compounds (B) may be used singly or in combination of two or more in any proportion. In one embodiment, from the viewpoint of interaction with the conductive polymer (A), the conductive composition preferably contains a quaternary ammonium compound (b-1). That is, the basic compound (B) preferably contains a quaternary ammonium compound (b-1).

[0118] <Solvent (D)> The solvent (D) is not particularly limited as long as it can dissolve at least the conductive polymer (A) and the surfactant (C), as long as it has the effects of the present invention. Examples of the solvent (D) include water, organic solvents, and mixed solvents of water and organic solvents. Examples of water include water from among the polymerization solvents exemplified above in the description of the method for producing the conductive polymer (A). Examples of the organic solvent include organic solvents from among the polymerization solvents exemplified above in the description of the method for producing the conductive polymer (A), and good solvents exemplified above in the description of the surfactant (C). When a mixed solvent of water and an organic solvent is used as the solvent (D), the mass ratio thereof (water / organic solvent) is preferably 1 / 100 to 100 / 1, and more preferably 2 / 100 to 100 / 2.

[0119] (Optional Components) Examples of optional components include polymer compounds (excluding the conductive polymer (A), basic compound (B), and surfactant (C)), additives, etc. Examples of polymer compounds include polyvinyl alcohol derivatives such as polyvinyl formal and polyvinyl butyral, and modified products thereof, starch and modified products thereof (oxidized starch, phosphated starch, cationized starch, etc.), cellulose derivatives (carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, and salts thereof, etc.), polyacrylamides such as poly(N-t-butylacrylamide) and polyacrylamidomethylpropanesulfonic acid, polyvinylpyrrolidone, polyacrylic acid (salts), polyethylene glycol, water-soluble alkyd resins, water-soluble melamine resins, water-soluble urea resins, water-soluble phenolic resins, water-soluble epoxy resins, water-soluble polybutadiene resins, water-soluble acrylic resins, water-soluble urethane resins, water-soluble acrylic-styrene copolymer resins, water-soluble vinyl acetate acrylic copolymer resins, water-soluble polyester resins, water-soluble styrene-maleic acid copolymer resins, water-soluble fluororesins, and copolymers thereof. Examples of additives include pigments, antifoaming agents, ultraviolet absorbers, antioxidants, heat resistance improvers, leveling agents, anti-sagging agents, matting agents, and preservatives.

[0120] (Content) The content of the conductive polymer (A) is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.5% by mass or more, and preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass or less, relative to the total mass of the conductive composition. The lower and upper limits of the content of the conductive polymer (A) can be arbitrarily combined, and for example, are preferably 0.1 to 5% by mass, more preferably 0.2 to 3% by mass, and even more preferably 0.5 to 2% by mass. The content of the conductive polymer (A) is preferably 50 to 99.9% by mass, more preferably 80 to 99.9% by mass, and even more preferably 95 to 99.9% by mass, relative to the total mass of the solid content of the conductive composition. The solid content of the conductive composition is the residue after removing the solvent (D) from the conductive composition. When the content of the conductive polymer (A) is within the above range, an excellent balance between the coatability of the conductive composition and the conductivity of the conductive film formed from the conductive composition is achieved.

[0121] The content of the basic compound (B) is preferably 5 to 80 parts by mass, more preferably 5 to 50 parts by mass, and even more preferably 5 to 30 parts by mass, per 100 parts by mass of the conductive polymer (A). When the content of the basic compound (B) is equal to or greater than the lower limit, even if the conductive polymer (A) contains acidic groups, the basic compound (B) can sufficiently form salts with the acidic groups of the conductive polymer (A) and the oxidizing agent, making it difficult for the acidic groups to be released. Furthermore, the basic compound (B) also sufficiently forms salts with the decomposition products of the oxidizing agent. Therefore, migration of the acidic groups and the decomposition products of the oxidizing agent to the resist layer is suppressed, thereby suppressing film loss of the resist layer. When the content of the basic compound (B) is equal to or less than the upper limit, the content of the conductive polymer (A) in the conductive composition can be sufficiently ensured, thereby enabling the formation of a conductive film with good conductivity. Furthermore, when the conductive polymer (A) contains acidic groups, these acidic groups exist in an appropriate free state in the conductive film without forming salts with the basic compound (B), thereby maintaining good conductivity. In particular, when the conductive polymer (A) has an acidic group or a salt thereof, the content of the basic compound (B) is preferably 0.1 to 1 mol equivalent, more preferably 0.1 to 0.9 mol equivalent, relative to 1 mol of units having an acidic group among the units constituting the conductive polymer (A), from the viewpoint of further improving the coatability of the conductive composition. Furthermore, from the viewpoint of excellent performance retention as a conductive film and further stabilizing the acidic group in the conductive polymer (A), 0.25 to 0.85 mol equivalent is particularly preferred.

[0122] The content of the surfactant (C) is preferably 5 to 200 parts by mass, and more preferably 10 to 100 parts by mass, relative to 100 parts by mass of the conductive polymer (A). When the content of the surfactant (C) is within the above range, the coatability of the conductive composition onto the resist layer is further improved.

[0123] The content of the solvent (D) is preferably 1 to 99% by mass, more preferably 10 to 99% by mass, and even more preferably 50 to 99% by mass, relative to the total mass of the conductive composition. When the content of the solvent (D) is within the above range, the coatability is further improved. When the conductive polymer (A) is used in a state where it is dispersed or dissolved in an aqueous medium after purification or the like (hereinafter, the conductive polymer (A) in this state is also referred to as a "conductive polymer solution"), the aqueous medium derived from the conductive polymer solution is also included in the content of the solvent (D) in the conductive composition. Furthermore, the total amount of all components constituting the conductive composition does not exceed 100% by mass.

[0124] <Method for producing conductive composition> One embodiment of the present invention is a method for producing a conductive composition. The method for producing a conductive composition of this embodiment includes a step of producing a water-soluble composition (C) by the above-mentioned method for producing a surfactant of the present invention (hereinafter also referred to as a "water-soluble composition production step"), and a step of mixing the water-soluble composition obtained in the water-soluble composition production step with a conductive polymer (A) (hereinafter also referred to as a "mixing step").

[0125] In the water-soluble composition production step, for example, when the water-soluble composition (C) is purified by a reprecipitation method, the water-soluble composition (C) is obtained in the form of a wet powder as described above. The wet powder may be subjected to the mixing step after being dried, or may be subjected to the mixing step as the wet powder.

[0126] In the mixing step, the conductive polymer (A) and the water-soluble composition (C) are mixed. In the mixing step, the conductive polymer (A) and the water-soluble composition (C) are preferably mixed with one or more of a basic compound (B), a solvent (D), and optional components, as needed. For example, since the conductive polymer (A) produced by the above-described method for producing the conductive polymer (A) after washing is solid, the solid conductive polymer (A) and the water-soluble composition (C) can be mixed with one or more of a basic compound (B), a solvent (D), and optional components, as needed, to form a conductive composition. When using a conductive polymer (A) that has been further purified by ion exchange after washing, the conductive polymer (A) after the ion exchange treatment is obtained in the form of a conductive polymer solution, as described above. Therefore, the conductive polymer solution may be mixed with the water-soluble composition (C) to form a conductive composition, or one or more of a basic compound (B) and optional components may be further added as needed, or the resultant may be further diluted with a solvent (D).

[0127] <Effects> The conductive composition of the present embodiment described above contains the water-soluble composition of the present invention, and therefore has good applicability and is less likely to produce foreign matter when formed into a coating film.

[0128] <Uses> The conductive composition of this embodiment is suitable for use in preventing static electricity during charged particle beam writing. Specifically, the conductive composition of this embodiment is applied to the surface of a resist layer in a charged particle beam pattern formation method using a chemically amplified resist or a non-chemically amplified resist to form a conductive film. The conductive film thus formed serves as an antistatic film for the resist layer. In addition to the above, the conductive composition of this embodiment can also be used as a material for, for example, capacitors, transparent electrodes, semiconductors, etc.

[0129] [Conductive film and manufacturing method thereof] One embodiment of a conductive film formed from the conductive composition of the present invention and a manufacturing method thereof will be described. The conductive film of this embodiment is a film formed from the conductive composition of the present invention described above, and contains the conductive polymer (A) described above and the water-soluble composition (C) of the present invention. In addition to the conductive polymer (A) and the water-soluble composition (C), the conductive film may further contain the basic compound (B) described above. Furthermore, in addition to the conductive polymer (A), the basic compound (B), and the water-soluble composition (C), the conductive film may further contain the optional components described above.

[0130] The method for producing a conductive film of this embodiment includes the following film formation step. The method for producing a conductive film of this embodiment may further include the following substrate preparation step and resist layer formation step before the film formation step.

[0131] <Substrate Preparation Step> Examples of the substrate include molded products of various polymer compounds such as polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polyolefin resins such as polyethylene and polypropylene, vinyl chloride, nylon, polystyrene, polycarbonate, epoxy resins, fluororesins, polysulfone, polyimide, polyurethane, phenolic resins, silicone resins, and synthetic paper, as well as films, paper, iron, glass, quartz glass, various wafers, various mask blanks, aluminum, copper, zinc, nickel, stainless steel, and the like, as well as substrates whose surfaces are coated with various paints, photosensitive resins, etc. The shape of the substrate is not particularly limited, and may be plate-like or may have a shape other than a plate-like shape.

[0132] <Resist Layer Forming Step> The resist layer forming step is a step of forming a resist layer on a substrate. In this specification, the substrate on which the resist layer is formed is also referred to as a "substrate with a resist layer."

[0133] The resist layer is obtained by applying a resist to a substrate. Examples of resists include positive resists and negative resists. The positive resist is not particularly limited as long as it is sensitive to ionizing radiation, and known resists can be used. A typical example is a chemically amplified resist containing an acid generator that generates acid upon irradiation with ionizing radiation and a polymer containing a structural unit having an acid-decomposable group. The negative resist is not particularly limited as long as it is sensitive to ionizing radiation, and known resists can be used. A typical example is a chemically amplified resist containing an acid generator that generates acid upon irradiation with ionizing radiation, a polymer soluble in a developer, and a crosslinking agent.

[0134] The resist layer can be formed by a known method. For example, a solution of a positive or negative resist in an organic solvent is applied to one surface of a substrate, and heated (prebaked) as necessary to form a positive or negative resist layer. The resist application method is the same as the application method of the conductive composition described below. The film thickness of the resist layer is not particularly limited, but is preferably 50 to 200 nm, and more preferably 70 to 150 nm.

[0135] <Film Forming Step> The film forming step is a step of forming a conductive film on a substrate. The film forming step is a step of forming a conductive film. The conductive film is obtained by applying a conductive composition to a substrate and drying it. If necessary, a heat treatment may be performed after drying. When a resist layer is formed on the substrate, the conductive film is formed on the resist layer of the substrate with the resist layer. When a resist layer is not formed on the substrate, the conductive film is formed directly on the surface of the substrate. The conductive film is preferably a conductive film formed on a substrate, or a conductive film formed on the resist layer of a substrate with a resist layer.

[0136] Examples of methods for applying the conductive composition include spin coating, spray coating, dip coating, roll coating, gravure coating, reverse coating, roll brushing, air knife coating, and curtain coating. The drying temperature is preferably less than 40°C. The drying time is preferably within one hour. From the viewpoint of conductivity, the heat treatment temperature is preferably in the range of 40°C to 250°C, and more preferably in the range of 60°C to 200°C. From the viewpoint of stability, the treatment time is preferably within one hour, and more preferably within 30 minutes. The film thickness of the conductive film is preferably 1 to 100 nm, more preferably 5 to 50 nm, and even more preferably 5 to 30 nm.

[0137] <Operation and Effect> The conductive film of the present embodiment described above is formed from the conductive composition of the present invention, and therefore the generation of foreign matter is suppressed.

[0138] <Applications> The method for manufacturing a conductive film according to this embodiment can be applied to, for example, a method for manufacturing a mask blank with a conductive film, a method for manufacturing a mask, and a method for manufacturing a semiconductor device.

[0139] [Method for manufacturing mask blanks with conductive film] One embodiment of a method for manufacturing a mask blank with a conductive film will be described. The method for manufacturing a mask blank with a conductive film of this embodiment includes a step of forming a conductive film on a mask blank using the method for manufacturing a conductive film of the present invention described above. Specifically, it is as follows.

[0140] A mask blank is used as the substrate, and a conductive film is formed on the mask blank to obtain a mask blank with a conductive film. The method for forming the conductive film is the same as the film forming process described above. It is preferable to form a resist layer on the mask blank before forming the conductive film on the mask blank. In other words, it is preferable to form a conductive film on the resist layer of the mask blank on which the resist layer has been formed. The method for forming the resist layer is the same as the resist layer forming process described above.

[0141] Known mask blanks can be used, and those suited to the configuration of the desired mask may be used. Specific examples of mask blanks include those comprising a light-transmitting substrate and a thin film provided on the light-transmitting substrate. Examples of the light-transmitting substrate include soda-lime glass, low-expansion glass, and quartz glass. Examples of the thin film include a light-shielding film, an anti-reflection film, a phase shift film, and an anti-oxidation film. The thin film may have a single-layer structure or a multi-layer structure.

[0142] [Mask Manufacturing Method] One embodiment of a mask manufacturing method will be described. The mask manufacturing method of this embodiment includes a step of manufacturing a mask blank with a conductive film, and a step of manufacturing a mask using the obtained mask blank with a conductive film. Specifically, it is as follows.

[0143] First, a mask blank with a conductive film is manufactured. For example, a mask blank with a conductive film may be manufactured by forming a conductive film on a mask blank using the above-described method for manufacturing a conductive film, or a mask blank with a conductive film may be manufactured using the above-described method for manufacturing a mask blank with a conductive film. Note that, before forming a conductive film on the mask blank, it is preferable to form a resist layer on the mask blank. In other words, it is preferable to manufacture a mask using a mask blank with a conductive film in which a resist layer and a conductive film are formed in this order on the mask blank.

[0144] Next, a mask is manufactured using the mask blank with a conductive film. The mask manufacturing process includes, for example, the following steps: an ionizing radiation irradiation step, a water washing and development step, an etching step, and a resist layer removal step.

[0145] The ionizing radiation irradiation process is a process of irradiating the resist layer of a mask blank with a conductive film with ionizing radiation in a pattern. Specifically, the mask blank with a conductive film is irradiated with ionizing radiation from the conductive film side. Examples of ionizing radiation include charged particle beams such as electron beams and ion beams; and electromagnetic waves such as X-rays and gamma rays. The ionizing radiation irradiation process forms a latent image in the resist layer between the mask blank and the conductive film. When the resist layer is made of a chemically amplified resist, acid is generated from an acid generator in the area exposed to ionizing radiation. At this time, since a conductive film is provided on the surface of the resist layer, the conductive film can be grounded, preventing charging of the entire mask blank with a conductive film. This prevents shifting of the position of electrons incident on the resist layer due to the influence of charging, allowing a latent image corresponding to the desired resist pattern to be formed with high accuracy.

[0146] The water washing and development process is a process in which the conductive film is removed by washing with water and the resist layer is developed to form a resist pattern. Since the conductive film is water-soluble, washing with water dissolves and removes the conductive film. Water washing refers to contacting with an aqueous liquid. Examples of aqueous liquids include simple water, water containing at least one of a base and a basic salt, water containing an acid, and a mixture of water and a water-soluble organic solvent.

[0147] When a positive resist layer is developed, the portions of the positive resist layer that have been irradiated with ionizing radiation are dissolved and removed, forming a resist pattern consisting of the portions of the positive resist layer that have not been irradiated with ionizing radiation.On the other hand, when a negative resist layer is developed, the portions that have not been irradiated with ionizing radiation are dissolved and removed, forming a resist pattern consisting of the portions of the negative resist layer that have been irradiated with ionizing radiation, in contrast to the case of a positive resist layer.

[0148] The water washing and development step can be carried out by, for example, the following method (α) or (β). Method (α): An alkaline developer is used for water washing to remove the conductive film and develop the resist layer at the same time. Method (β): Only the conductive film is removed by water washing, and then the resist layer is developed with a developer.

[0149] The alkaline developer (alkaline aqueous solution) used in method (α) is not particularly limited, and known ones can be used. For example, an aqueous solution of tetramethylammonium hydroxide can be used. The water washing in method (β) can be carried out using an aqueous liquid that does not fall under the category of a developer, such as water. Development can be carried out using an alkaline developer, as in method (α).

[0150] After the water-washing and development step, the substrate may be rinsed with pure water, etc., if necessary. After the water-washing and development step or the rinsing step, the substrate on which the resist pattern has been formed may be heated (post-baked), if necessary.

[0151] The etching process is a process of etching the thin film of the mask blank using a resist pattern as a mask. By etching, the thin film in the portions not masked by the resist pattern (i.e., the exposed portions) is removed. As the etching method, a method known per se can be used, such as dry etching or wet etching.

[0152] The resist removal process is a process of removing the resist pattern remaining on the mask blank after etching. By removing the resist pattern, a mask (photomask) on which a pattern is formed can be obtained. A known stripping agent can be used to remove the resist pattern.

[0153] [Method for Manufacturing a Semiconductor Device] One embodiment of a method for manufacturing a semiconductor device will be described. The method for manufacturing a semiconductor device of this embodiment includes a step of forming a conductive film on a substrate using the above-mentioned method for manufacturing a conductive film to obtain a laminate, and a step of manufacturing a semiconductor device using the laminate. Specifically, the method is as follows.

[0154] First, a conductive film is formed on a substrate to obtain a laminate. The method for forming the conductive film is the same as in the film formation process described above. It is preferable to form a resist layer on the substrate before forming the conductive film on the substrate. That is, it is preferable to use a substrate with a resist layer, form a conductive film on the resist layer of the substrate with a resist layer, and manufacture a semiconductor device using a laminate in which the resist layer and the conductive film are formed in this order on the substrate. The method for forming the resist layer is the same as in the resist layer formation process described above. As the substrate, a known material used as a substrate for semiconductor devices can be used. For example, a silicon wafer can be used.

[0155] Next, a semiconductor device is manufactured using the laminate. The manufacturing process for the semiconductor device includes, for example, the ionizing radiation irradiation step described below. If necessary, the manufacturing process may further include the water washing step, the development step, the etching step, and the resist layer removal step described below.

[0156] The ionizing radiation irradiation process is a process in which ionizing radiation such as electron beams or ion beams is irradiated onto the laminate to form a wiring pattern. Since a conductive film is provided on the surface of the substrate or resist layer, the conductive film can be grounded, preventing the entire laminate from becoming charged. This prevents the position of electrons incident on the substrate or resist layer from shifting due to the influence of charging, allowing a latent image corresponding to the transferred pattern to be formed with high precision.

[0157] The water washing step and the developing step are the same as the water washing / developing step in the above-mentioned method for producing a mask. The water washing step and the developing step may be performed simultaneously (method (α)), or the developing step may be performed after the water washing step (method (β)). The etching step is the same as the etching step in the above-mentioned method for producing a mask. The resist layer removing step is the same as the resist layer removing step in the above-mentioned method for producing a mask.

[0158] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these.

[0159] [Production of Conductive Polymer (A)] 100 mmol of pyridine and 100 mL of water were added to 100 mmol of 2-aminoanisole-4-sulfonic acid to obtain a monomer solution. An aqueous solution of 100 mmol of ammonium peroxodisulfate (oxidant solution) was added dropwise to the obtained monomer solution at 10°C. After the dropwise addition, the mixture was further stirred at 25°C for 15 hours, then heated to 35°C and stirred for an additional 2 hours to obtain a reaction solution in which the reaction product had precipitated (polymerization step). The obtained reaction solution was filtered using a centrifugal filter, and the precipitate (reaction product) was recovered. The reaction product was washed with 1 L of methanol and then dried. 20 g of the dried reaction product was dissolved in 980 g of pure water to obtain 1,000 g of a conductive polymer solution (A1-1) with a solids concentration of 2% by mass. 500 mL of a cation exchange resin ("Amberlite IR-120B" manufactured by Organo Corporation) washed with ultrapure water was packed into a column. 1000 g of the conductive polymer solution (A1-1) was passed through this column at a rate of 50 mL / min (SV=6) to obtain 900 g of a conductive polymer solution (A1-2) from which basic substances and the like had been removed. Next, 500 mL of anion exchange resin ("Amberlite IRA410" manufactured by Organo Corporation) washed with ultrapure water was packed into the column. 900 g of the conductive polymer solution (A1-2) was passed through this column at a rate of 50 mL / min (SV=6) to obtain 800 g of a conductive polymer solution (A1-3) from which basic substances and the like had been removed. The heating residue of this conductive polymer solution (A1-3) was measured and found to be 2.0% by mass. In other words, the solids concentration of the conductive polymer solution (A1-3) was 2.0% by mass. Note that 1 sverdrup (SV) is 1 x 10 ６ m ３ / s (1 GL / s).

[0160] [Measurement and Evaluation Methods] <Quantitative Analysis of Component (X)> The content of component (X) in water-soluble composition (C) was quantified by the following measurement method. (Measurement Method) <Creation of Calibration Curve> n-Dodecyl mercaptan, the chain transfer agent used in producing water-soluble composition (C), was dissolved in a mixed solvent containing water and methanol at a volume ratio (water / methanol) of 2 / 8 to give concentrations of 500 mg / L, 100 mg / L, 50 mg / L, and 10 mg / L, respectively, to prepare solutions (III-1) to (III-4). Separately, n-Ethyl caproate was dissolved in methanol to give a concentration of 5 mg / L to prepare solution (I). Solutions (III-1) to (III-4) were mixed with solution (I) at a volume ratio (solution (I) / solution (III)) of 1 / 10 to prepare samples (S2) to (S5), which were then analyzed by gas chromatography under the conditions shown below. Each of the samples (S2) to (S5) was injected into a gas chromatograph, and the time when the column oven was heated to 50°C was set as time 0. The temperature was then raised to 300°C at a rate of 10°C / min, and the sample was held at 300°C for 10 minutes. In a 35-minute analysis, the areas of the peaks obtained between 25 and 35 minutes were determined, and a calibration curve was created showing the relationship between the concentration ratio of n-dodecyl mercaptan and ethyl n-caproate, which is an internal standard, and the peak area ratio.

[0161] Quantitative Analysis of Component (X) Ethyl n-caproate was dissolved in methanol to a concentration of 5 mg / L to prepare solution (I). Separately, solution (II) was prepared by dissolving water-soluble composition (C) in a mixed solvent containing water and methanol at a volume ratio (water / methanol) of 2 / 8 to a concentration of 0.2 mass%. Solution (I) and solution (II) were mixed at a volume ratio (solution (I) / solution (II)) of 1 / 10 to prepare sample (S1), which was then analyzed by gas chromatography under the conditions shown below. Sample (S1) was injected into a gas chromatograph, and the time point at which the column oven was heated to 50°C was designated as time 0. The temperature was then increased to 300°C at a rate of 10°C / min, and the sample was held at 300°C for 10 minutes. The peak area obtained between 25 and 35 minutes was quantified against a previously prepared calibration curve, and this value was taken as the content (concentration) of component (X) in water-soluble composition (C). Here, the quantitative determination was carried out by converting the relative value with respect to the internal standard substance, ethyl n-caproate, into an absolute value.

[0162] <Gas Chromatography Analysis Conditions> Apparatus: 7890 Gas Chromatograph (Agilent Technologies). Column: DB-5 (30 m x 0.53 mmφ x 1.5 μm) Column No. E11 (Agilent Technologies). Injection port temperature: 200°C. Detector: FID. Detector temperature: 300°C. Injection method: splitless. Carrier gas: He. Pressure: 35 kPa (constant pressure). Initial column flow rate: 7 mL / min. Injection volume: 1 μL.

[0163] <Measurement of Molecular Weight of Water-Soluble Polymer (B)> A 0.1% by mass aqueous solution of the water-soluble polymer (B) was filtered through a 0.45 μm membrane filter to prepare a sample. GPC measurement of the sample was carried out under the following conditions to measure the mass average molecular weight of the water-soluble polymer (B). <GPC Measurement Conditions> Measuring instrument: TOSOH GPC-8020 (manufactured by Tosoh Corporation) Eluent: 0.2 M NaNO ３DIW / acetonitrile = 80 / 20 (v / v) Column temperature: 30°C Calibration curve: Prepared using EasiVial™ polyethylene glycol / oxide (PolymerLab)

[0164] <Appearance Evaluation> The appearance of aqueous solutions prepared by dissolving the water-soluble composition (C) in water to a concentration of 1.0% by mass or 0.5% by mass was visually observed, and the appearance was evaluated according to the following evaluation criteria. A is considered to be pass. A: No turbidity is observed even in an aqueous solution with a concentration of 1.0% by mass. B: Turbidity occurs in an aqueous solution with a concentration of 1.0% by mass, but no turbidity is observed in an aqueous solution with a concentration of 0.5% by mass. C: Turbidity occurs in an aqueous solution with a concentration of 0.5% by mass.

[0165] <Evaluation of Conductivity> The conductive composition was spin-coated (1000 rpm x 180 sec) onto an 8-inch silicon wafer substrate, and heated on a hot plate at 80°C for 2 minutes to obtain a test piece with a conductive film (film thickness 20 nm) formed on the substrate. The surface resistivity [Ω / □] of the conductive film was measured by the two-terminal method (electrode distance 20 mm) using a Hiresta UX-MCP-HT800 (manufactured by Nitto Seiko Analytech Co., Ltd.).

[0166] <Measurement of pH> The pH of the conductive composition at 25° C. was measured using a pH meter (manufactured by Horiba Ltd., product name "F-55").

[0167] <Evaluation of Coatability> 1 mL of the conductive composition was dropped onto an 8-inch silicon wafer as a substrate and coated with a spin coater. The coated state was visually observed, and the coatability was evaluated according to the following evaluation criteria. A is considered to be acceptable. A: The wafer was evenly coated. B: The wafer was coated, but there was unevenness.

[0168] <Evaluation of foreign matter generation> A conductive composition was spin-coated (1000 rpm x 180 sec) onto an 8-inch silicon wafer as a substrate, and heated on a hot plate at 80°C for 2 minutes to obtain a test piece having a conductive film (film thickness 20 nm) formed on the substrate. The obtained test piece was observed under a microscope (magnification: 1000x) using an SEM linked to an optical wafer visual inspection device (manufactured by Hitachi High-Tech Corporation, product name "SR-7300") to determine whether the conductive film was 1 mm thick or not.２ The number of foreign particles (α) generated per 1 mm of substrate was counted. Note that the foreign particles counted were those with a maximum diameter of 0.3 μm or more. Similarly, for an 8-inch silicon wafer before the conductive composition was applied, ２ The number (β) of foreign matter with a longest diameter of 0.3 μm or more present per unit area was measured, and the number of foreign matter originating from the conductive composition (α-β) was calculated. The occurrence of foreign matter was evaluated according to the following evaluation criteria. A is considered to be pass. AA: The number of foreign matter originating from the conductive composition is 30 or less. A: The number of foreign matter originating from the conductive composition is 31 to 50. B: The number of foreign matter originating from the conductive composition is 51 to 100. C: The number of foreign matter originating from the conductive composition is 101 or more.

[0169] [Example 1] <Production of Water-Soluble Composition (C)> 55 g (0.49 mol) of N-vinylpyrrolidone, 3 g (15.60 mmol) of azobismethylbutyronitrile as a polymerization initiator, and 1 g (4.94 mmol) of n-dodecyl mercaptan as a chain transfer agent were dissolved in 100 mL of isopropyl alcohol with stirring to obtain a reaction solution. Thereafter, the reaction solution was added dropwise at a rate of 1 mL / min to 100 mL of isopropyl alcohol that had been preheated to 80°C, and dropwise polymerization was carried out. The dropwise polymerization was carried out while maintaining the temperature of the isopropyl alcohol at 80°C. After completion of the dropwise addition, the mixture was further aged at 80°C for 2 hours to complete the polymerization (polymerization step). The mixture was then allowed to cool and further concentrated under reduced pressure to obtain a water-soluble polymer solution. The heating residue of this water-soluble polymer solution was measured and found to be 60.0% by mass. In other words, the solids concentration of the water-soluble polymer solution was 60.0% by mass. Next, 10 g of the water-soluble polymer solution was added dropwise to 50 g of diethyl ether and 50 g of hexane as poor solvents while stirring them. After the entire amount of the water-soluble polymer solution was added dropwise, the mixture was stirred for 30 minutes (reprecipitation step). The "amount of poor solvent" in Table 1 refers to the amount (mixed amount) (parts by mass) of the poor solvent used in the reprecipitation step relative to 100 parts by mass of the water-soluble polymer solution, which is a good solvent solution. The precipitate formed in the poor solvent was then recovered by decantation and dried under reduced pressure at 70°C for 3 hours to obtain a powder of water-soluble composition (C1) containing a water-soluble polymer with surfactant properties. The component (X) in the resulting water-soluble composition (C1) was quantified, and the appearance of the aqueous solution was evaluated. The results are shown in Table 1. The mass-average molecular weight of the water-soluble polymer was 1,200. The surface tension of a 1.0% aqueous solution of the water-soluble composition (C1) was 35.3.

[0170] <Preparation of Conductive Composition> A conductive composition was obtained by mixing 30 parts by mass of the conductive polymer solution (A1-3) (0.6 parts by mass in terms of solids), 0.3 parts by mass of tetrabutylammonium hydroxide as the basic compound (B), 0.1 parts by mass of the water-soluble composition (C1), and 5 parts by mass of isopropyl alcohol and 64.6 parts by mass of water as the solvent (D). Table 2 shows the contents of the conductive polymer (A), basic compound (B), water-soluble composition (C), and solvent (D) relative to the total mass of the conductive composition. The content of the conductive polymer (A) in Table 2 is the amount converted to solids (net amount). The water content also includes the amount of water (29.4 parts by mass) derived from the conductive polymer solution (A1-3). The pH of the obtained conductive composition was measured, and the conductivity, coatability, and generation of foreign matter were evaluated. The results are shown in Table 2.

[0171] [Examples 2 and 3] Water-soluble compositions (C2) and (C3) were produced in the same manner as in Example 1, except that the types of poor solvents shown in Table 1 were used. The component (X) in the resulting water-soluble compositions (C2) and (C3) was quantified, and the appearance of the aqueous solution was evaluated. The results are shown in Table 1. Furthermore, conductive compositions were produced in the same manner as in Example 1, except that the resulting water-soluble compositions (C2) and (C3) were used. The pH of the resulting conductive compositions was measured, and the conductivity, coatability, and generation of foreign matter were evaluated. The results are shown in Table 2. The surface tension of a 1.0% aqueous solution of the water-soluble composition (C2) was 35.1.

[0172] Example 4 A water-soluble polymer solution having a solids concentration of 60.0% by mass was prepared in the same manner as in Example 1, except that 3 g of dilauroyl peroxide was used instead of 3 g of azobismethylbutyronitrile as the polymerization initiator and the same amount of ethyl acetate was used instead of isopropyl alcohol as the solvent. Next, a reprecipitation step was carried out in the same manner as in Example 1, except that the poor solvent shown in Table 1 was used, to prepare a water-soluble composition (C4). The component (X) in the obtained water-soluble composition (C4) was quantified, and the appearance of the aqueous solution was evaluated. The results are shown in Table 1. Furthermore, a conductive composition was prepared in the same manner as in Example 1, except that the obtained water-soluble composition (C4) was used. The pH of the obtained conductive composition was measured, and the conductivity, coatability, and generation of foreign matter were evaluated. The results are shown in Table 2. The surface tension of a 1.0% aqueous solution of the water-soluble composition (C4) was 34.3.

[0173] Comparative Example 1 A water-soluble polymer solution having a solids concentration of 60.0% by mass was prepared in the same manner as in Example 1. The obtained water-soluble polymer solution was dried under reduced pressure at 70°C for 3 hours to obtain a powder of a water-soluble polymer, water-soluble composition (C5). The component (X) in the obtained water-soluble composition (C5) was quantified, and the appearance of the aqueous solution was evaluated. The results are shown in Table 1. A conductive composition was also prepared in the same manner as in Example 1, except that the obtained water-soluble composition (C5) was used. The pH of the obtained conductive composition was measured, and the conductivity, coatability, and generation of foreign matter were evaluated. The results are shown in Table 2.

[0174] Comparative Example 2 A water-soluble composition (C6) was produced in the same manner as in Example 1, except that the type of poor solvent shown in Table 1 was used. The component (X) in the obtained water-soluble composition (C6) was quantified, and the appearance of the aqueous solution was evaluated. The results are shown in Table 1. Furthermore, a conductive composition was produced in the same manner as in Example 1, except that the obtained water-soluble composition (C6) was used. The pH of the obtained conductive composition was measured, and the conductivity, coatability, and generation of foreign matter were evaluated. The results are shown in Table 2. The surface tension of a 1.0% aqueous solution of the water-soluble composition (C6) was 33.3.

[0175] Comparative Examples 3 to 5 A water-soluble polymer solution having a solids concentration of 60.0% by mass was prepared in the same manner as in Example 1, except that 3 g of dilauroyl peroxide was used instead of 3 g of azobismethylbutyronitrile as the polymerization initiator and the same amount of ethyl acetate was used instead of isopropyl alcohol as the solvent. Next, a reprecipitation step was carried out in the same manner as in Example 1, except that the poor solvents shown in Table 1 were used, to prepare water-soluble compositions (C7) to (C9). The component (X) content of the resulting water-soluble compositions (C7) to (C9) was quantified, and the appearance of the aqueous solutions was evaluated. The results are shown in Table 1. The water-soluble polymer had a mass-average molecular weight of 2,200. Furthermore, conductive compositions were prepared in the same manner as in Example 1, except that the resulting water-soluble compositions (C7) to (C9) were used. The pH of the resulting conductive compositions was measured, and the conductivity, coatability, and generation of foreign matter were evaluated. The results are shown in Table 2. The surface tension of a 1.0% aqueous solution of the water-soluble composition (C7) was 32.8. The surface tension of a 1.0% aqueous solution of the water-soluble composition (C8) was 33.5.

[0176]

[0177]

[0178] The abbreviations in Tables 1 and 2 mean the following: NVP: N-vinylpyrrolidone. nDM: n-dodecyl mercaptan. AMBN: azobismethylbutyronitrile. LPO: dilauroyl peroxide. IPA: isopropyl alcohol. EtOAc: ethyl acetate. DEE: diethyl ether. DIPE: diisopropyl ether. TMPE: t-butyl methyl ether. HEX: hexane. TBAH: tetrabutylammonium hydroxide.

[0179] As is clear from Table 1, it was shown that the impurity, i.e., component (X), in the water-soluble polymer as determined by GC-FID can be controlled to a predetermined concentration by reprecipitation using a poor solvent containing an ether or a poor solvent containing an ether and an alkane. Furthermore, as is clear from Table 2, it was shown that the use of a conductive composition containing a water-soluble composition in which the impurity concentration is controlled to a predetermined concentration can reduce foreign matter (defects) in the conductive film while maintaining conductivity and coatability.

Claims

1. A water-soluble composition comprising a water-soluble polymer and satisfying the following conditions (A1) and (A2): (A1) the water-soluble polymer comprises a nitrogen-containing functional group, (A2) a 1.0% by mass aqueous solution of the water-soluble composition has a surface tension of 34.0 to 50.0 at 25°C.

2. The water-soluble composition according to claim 1, further satisfying the following condition (A3): (A3) The water-soluble composition contains a component, as quantified by the following measurement method, in an amount of more than 0 ppm by mass and not more than 1.3 ppm by mass: <Measurement method> A solution (I) in which ethyl n-caproate is dissolved in methanol to a concentration of 5 mg / L, and a solution (II) in which the water-soluble composition is dissolved in a mixed solvent having a volume ratio of water to methanol (water / methanol) of 2 / 8 to a concentration of 0.2% by mass are mixed in a volume ratio (solution (I) / solution (II)) of 1 / 10 to obtain a sample (S1), which is analyzed by gas chromatography. After injecting the sample (S1) into a gas chromatograph, the time when the column oven is heated to 50° C. is set as 0 min, and the temperature is raised to 300° C. at a rate of 10° C. / min. and held at 300° C. for 10 min in a 35-min analysis. The peak area obtained during the period from 25 to 35 min is quantified by checking against a calibration curve prepared in advance using n-dodecyl mercaptan.

3. The water-soluble composition according to claim 1, further satisfying the following condition (A4): (A4) The water-soluble composition contains a component, as quantified by the following measurement method, in an amount of more than 0 ppm by mass and less than 1.0 ppm by mass. <Measurement method> A solution (I) in which ethyl n-caproate is dissolved in methanol to a concentration of 5 mg / L, and a solution (II) in which the water-soluble composition is dissolved in a mixed solvent having a volume ratio of water to methanol (water / methanol) of 2 / 8 to a concentration of 0.2% by mass are mixed together in a volume ratio (solution (I) / solution (II)) of 1 / 10 to obtain a sample (S1), which is analyzed by gas chromatography. After injecting the sample (S1) into a gas chromatograph, the time when the column oven is heated to 50° C. is set as 0 min, and the temperature is raised to 300° C. at a rate of 10° C. / min. and held at 300° C. for 10 min in a 35-min analysis. The peak area obtained during the period from 25 to 35 min is quantified by checking against a calibration curve prepared in advance using n-dodecyl mercaptan.

4. A water-soluble composition comprising a water-soluble polymer and satisfying the following conditions (B1) to (B3): (B1) the water-soluble polymer comprises a nitrogen-containing functional group; (B2) a 1.0% by mass aqueous solution of the water-soluble composition has a surface tension of 10.0 to 50.0 at 25°C; (B3) the water-soluble composition comprises a component quantified by the following measurement method in an amount of more than 0 ppm by mass and not more than 1.3 ppm by mass; <Measurement method> A solution (I) in which n-ethyl caproate is dissolved in methanol to a concentration of 5 mg / L, and a solution (II) in which the water-soluble composition is dissolved in a mixed solvent having a volume ratio of water to methanol (water / methanol) of 2 / 8 to a concentration of 0.2% by mass are mixed together in a volume ratio (solution (I) / solution (II)) of 1 / 10 to obtain a sample (S1) which is subjected to gas chromatography analysis. After injecting the sample (S1) into a gas chromatograph, the time when the column oven is heated to 50° C. is set as 0 min, and the temperature is raised to 300° C. at a rate of 10° C. / min. and held at 300° C. for 10 min in a 35-min analysis. The peak area obtained during the period from 25 to 35 min is quantified by checking against a calibration curve prepared in advance using n-dodecyl mercaptan.

5. The water-soluble composition according to claim 4, further satisfying the following condition (B4): (B4) The water-soluble composition contains a component, as quantified by the following measurement method, in an amount of more than 0 ppm by mass and less than 1.0 ppm by mass. <Measurement method> A solution (I) in which ethyl n-caproate is dissolved in methanol to a concentration of 5 mg / L, and a solution (II) in which the water-soluble composition is dissolved in a mixed solvent having a volume ratio of water to methanol (water / methanol) of 2 / 8 to a concentration of 0.2% by mass are mixed together in a volume ratio (solution (I) / solution (II)) of 1 / 10 to obtain a sample (S1), which is analyzed by gas chromatography. After injecting the sample (S1) into a gas chromatograph, the time when the column oven is heated to 50° C. is set as 0 min, and the temperature is raised to 300° C. at a rate of 10° C. / min. and held at 300° C. for 10 min in a 35-min analysis. The peak area obtained during the period from 25 to 35 min is quantified by checking against a calibration curve prepared in advance using n-dodecyl mercaptan.

6. The water-soluble composition according to claim 1 or 4, wherein the water-soluble polymer has a weight average molecular weight of 600 to 20,000.

7. The water-soluble composition according to claim 1 or 4, wherein the water-soluble polymer has a nitrogen-containing functional group.

8. The water-soluble composition according to claim 1 or 4, wherein the water-soluble polymer contains a pyrrolidone structure.

9. A conductive composition comprising the water-soluble composition according to claim 1 or 4 and a conductive polymer.

10. The conductive composition according to claim 9, wherein the conductive polymer comprises a conductive polymer having at least one unit selected from units represented by the following general formulas (1) to (4): In the general formulas (1) to (4), X represents a sulfur atom or a nitrogen atom; １ ~R １５ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group or a salt thereof, a hydroxyl group, a nitro group, a halogen atom, -N(R １６ ) ２ , -NHCOR １６ , -SR １６ , -OCOR １６ , -COOR １６ , -COR １６ , —CHO, or —CN. １６ represents an alkyl group having 1 to 24 carbon atoms, an aryl group having 6 to 24 carbon atoms, or an aralkyl group having 7 to 24 carbon atoms. １ , R ２ At least one of R in the general formula (2) ３ ~R ６ At least one of R in the general formula (3) ７ ~R １０ At least one of R in the general formula (4) １１ ~R １５ At least one of each is an acidic group or a salt thereof.

11. The conductive composition according to claim 9, wherein the conductive polymer comprises a conductive polymer having a unit represented by the following general formula (4): In general formula (4), R １１ ~R １５ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, an acidic group or a salt thereof, a hydroxyl group, a nitro group, a halogen atom, -N(R １６ ) ２ , -NHCOR １６ , -SR １６ , -OCOR １６ , -COOR １６ , -COR １６ , —CHO, or —CN. １６ represents an alkyl group having 1 to 24 carbon atoms, an aryl group having 6 to 24 carbon atoms, or an aralkyl group having 7 to 24 carbon atoms.

12. The conductive composition of claim 9, further comprising a basic compound.

13. The conductive composition of claim 12, wherein the basic compound comprises a quaternary ammonium compound.

14. A method for producing a water-soluble composition according to claim 1 or 4, comprising a reprecipitation step of mixing a good solvent solution containing the water-soluble polymer and a good solvent for the water-soluble polymer with a poor solvent for the water-soluble polymer, wherein the poor solvent contains an ether.

15. The method for producing a water-soluble composition according to claim 14, further comprising a step of synthesizing the water-soluble polymer, the step of reprecipitation being carried out after the step of synthesis, and the reaction solution in the step of synthesis being used as a good solvent solution in the step of reprecipitation.

16. The method for producing a water-soluble composition according to claim 14, wherein the amount of the poor solvent mixed is 100 parts by mass or more per 100 parts by mass of the good solvent solution.

17. The method of producing the water-soluble composition of claim 14, wherein the antisolvent further comprises an alkane.

18. The method for producing a water-soluble composition according to claim 17, wherein the mass ratio of the alkane to the ether (alkane / ether) is 0.5 to 2.

0.

19. A method for producing a conductive composition, comprising: a step of producing a water-soluble composition by the method for producing a water-soluble composition according to claim 14; and a step of mixing the water-soluble composition obtained in the step of producing a water-soluble composition with a conductive polymer.