JP2020132667A - Conductive polymer and conductive composition - Google Patents

Abstract

To provide a conductive polymer that has excellent surface smoothness.SOLUTION: Provided is a conductive polymer having a constitutional unit based on a compound (1) represented by the following formula (1), in which, in a chromatogram obtained by GPC, a ratio (X/Y) of an area (X) of a region having a molecular weight (M) of 1,000 or less to an area (Y) of the whole region derived from the conductive polymer is 0.05 to 0.3. In the formula, Rto Rare 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, a hydroxy group, a nitro group, or a halogen atom (-F, -Cl, -Br or I), and at least one of Rto Ris a hydrogen atom, at least one is an alkoxy group, and at least one is an acidic group.SELECTED DRAWING: None

Description

The present invention relates to conductive polymers and conductive compositions.

Pattern formation technology using charged particle beams such as electron beams and ion beams is expected as a next-generation technology for optical lithography. When a charged particle beam is used, it is important to improve the sensitivity of the resist layer in order to improve productivity.
Therefore, a highly sensitive chemically amplified resist that generates acid in the exposed part or the part irradiated with charged particle beams and then promotes the cross-linking reaction or decomposition reaction by heat treatment called post-exposure baking (PEB) treatment. Use is the mainstream.
Further, in recent years, with the trend of miniaturization of semiconductor devices, management of resist shapes on the order of several nm has been required.

By the way, in the pattern forming method using a charged particle beam, especially when the substrate is insulating, the trajectory of the charged particle beam is bent due to the electric field generated by the charge-up of the substrate, and a desired pattern is obtained. There is a problem that it is difficult to be charged.
As a means for solving this problem, a conductive composition containing a conductive polymer is applied to the surface of the resist layer to form a coating film, and the surface of the resist layer is coated with the coating film to prevent the resist layer from being charged. It is already known that the technique of granting is effective.

As a conductive polymer, polyaniline having an acidic group is known. Polyaniline having an acidic group can exhibit conductivity without adding a doping agent.
For example, Patent Document 1 describes an example in which a conductive composition containing a conductive polymer having an acidic group and a water-soluble polymer exhibiting surface-active ability is applied to the surface of a resist layer to form a conductive film. ing.

JP-A-2002-226721

In recent years, with the trend toward miniaturization of semiconductor devices, management of resist shapes on the order of several nm has been required. Therefore, the antistatic film formed on the resist layer is required to have surface smoothness.
However, the coating film of the conductive composition described in Patent Document 1 does not necessarily have sufficient surface smoothness.
An object of the present invention is to provide a conductive polymer and a conductive composition having excellent surface smoothness when formed into a coating film.

The present invention has the following aspects.
[1] It has a structural unit based on the compound (1) represented by the following formula (1), and the area ratio (X / Y) calculated by the evaluation method including the following steps (I) to (VI) is 0. .05-0.3, conductive polymer.
(I) A step of preparing a test solution by dissolving the conductive polymer in an eluent having a pH of 10 or more so that the solid content concentration of the conductive polymer is 0.1% by mass.
(II) A step of measuring the molecular weight distribution of the test solution using a polymer material evaluation device equipped with a gel permeation chromatograph to obtain a chromatogram.
(III) A step of converting the retention time of the chromatogram obtained in the step (II) into a molecular weight (M) in terms of sodium polystyrene sulfonate.
(IV) A step of determining the area (X) of a region having a molecular weight (M) of 1000 or less in the chromatogram obtained in the step (III).
(V) A step of determining the area (Y) of the entire region derived from the conductive polymer in the chromatogram obtained in the step (III).
(VI) A step of obtaining an area ratio (X / Y) of the area (X) and the area (Y).

(In the formula, R ^{1 to} R ⁵ are independently hydrogen atoms, linear or branched alkyl groups having 1 to 24 carbon atoms, linear or branched alkoxy groups having 1 to 24 carbon atoms, acidic groups, and the like. It is a hydroxy group, a nitro group, or a halogen atom (-F, -Cl, -Br or I), and at least one of R ^{1 to} R ⁵ is a hydrogen atom, at least one is an alkoxy group, and at least one. Is an acidic group.)
[2] The conductive polymer according to [1], wherein at least one of R ^{1 to} R ⁵ is a methoxy group.
[3] The conductive polymer of [1] or [2] for preventing static electricity when drawing a charged particle beam.
[4] A conductive composition containing the conductive polymer according to any one of [1] to [3] and a solvent.

According to the present invention, it is possible to provide a conductive polymer and a conductive composition having excellent surface smoothness when formed into a coating film.

This is an example of a chromatogram obtained by gel permeation chromatography in step (II) of the evaluation method.

Hereinafter, the present invention will be described in detail. The following embodiments are merely exemplary to illustrate the invention and are not intended to limit the invention to this embodiment alone. The present invention can be implemented in various aspects as long as it does not deviate from the gist thereof.

In the present invention, "conductive" means having a surface resistance value of 1 × 10 ¹¹ Ω / □ or less. The surface resistance value is obtained from the potential difference between the electrodes when a constant current is applied.
Further, in the present specification, "soluble" means simply water, water containing at least one of a base and a basic salt, water containing an acid, and 10 g of a mixture of water and a water-soluble organic solvent (liquid temperature 25). It means that it is uniformly dissolved in 0.1 g or more at ° C.). Further, "water-soluble" means the solubility in water with respect to the solubility.
Further, in the present specification, the "terminal" of the "terminal hydrophobic group" means a site other than the repeating unit constituting the polymer.
Further, in the present specification, the "mass average molecular weight" is a mass average molecular weight (in terms of sodium polystyrene sulfonate) measured by gel permeation chromatography (GPC).
In the present specification, the compound represented by the formula (1) is referred to as "compound (1)". Compounds represented by other formulas are also described in the same manner.
In the present specification, the structural unit based on compound (1) is referred to as “constituent unit (1)”. Other structural units are described in the same manner.

<Conductive polymer>
The conductive polymer (A) of the present invention has a structural unit (1) based on the compound (1) represented by the following formula (1).
The structural unit (1) is obtained by removing one or two hydrogen atoms bonded to the nitrogen atom of the compound (1) and one hydrogen atom bonded to the benzene ring.
The conductive polymer (A) of the present invention has an acidic group. If the conductive polymer (A) has an acidic group, the water solubility is enhanced. As a result, the coatability of the conductive composition containing the conductive polymer (A) is enhanced, and it becomes easy to obtain a coating film having a uniform thickness.

[Compound (1)]
In the formula (1), R ^{1 to} R ⁵ are independently hydrogen atoms, linear or branched alkyl groups having 1 to 24 carbon atoms, linear or branched alkoxy groups having 1 to 24 carbon atoms, and acidic groups. A group, a hydroxy group, a nitro group, or a halogen atom (-F, -Cl, -Br or I), at least one of R ^{1 to} R ⁵ is a hydrogen atom, at least one is an alkoxy group, and at least. One is an acidic group.
In the compound (1), the substituent other than the acidic group on the aromatic ring is preferably an electron donating group from the viewpoint of imparting reactivity to the compound (1). 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) and the like are preferable, and among these, from the viewpoint of electron donating property. , Alkoxy groups having 1 to 24 carbon atoms are most preferable.

The alkoxy group in the formula (1) is preferably a linear or branched alkoxy group having 1 to 4 carbon atoms, and more preferably a methoxy group. It is preferable that at least one of the R ^{1 to} R ⁵ is a methoxy group.

The acidic group in the formula (1) is preferably a sulfonic acid group (sulfo group) or a carboxylic acid group (carboxy group). The acidic group may form a salt.
The sulfonic acid group may be contained in the acid state (-SO ₃ H) or in the ionic state (-SO ₃ ⁻ ). Further, the sulfonic acid group also includes a substituent having a sulfonic acid group (-R ¹¹ SO ₃ H).
On the other hand, carboxylic acid groups, may be included in the form of an acid (-COOH), an ionic state ^- may be included in (-COO). Further, the carboxylic acid group also includes a substituent having a carboxylic acid group (-R ¹¹ COOH).
The R ¹¹ contains a linear or branched alkylene group having 1 to 24 carbon atoms, an arylene group having a linear or branched chain having 1 to 24 carbon atoms, or an aralkylene group having a linear or branched chain having 1 to 24 carbon atoms. Represent.

Examples of the salt of the acidic group include an alkali metal salt of a sulfonic acid group or a carboxylic acid group, an alkaline earth metal salt, an ammonium salt, a substituted ammonium salt and the like.
Examples of the alkali metal salt include lithium sulfate, lithium carbonate, lithium hydroxide, sodium sulfate, sodium carbonate, sodium hydroxide, potassium sulfate, potassium carbonate, potassium hydroxide and derivatives having a skeleton thereof.
Examples of the alkaline earth metal salt include magnesium salt and calcium salt.
Examples of the substituted ammonium salt include an aliphatic ammonium salt, a saturated alicyclic ammonium salt, and an unsaturated alicyclic ammonium salt.
Examples of the aliphatic ammonium salt include methylammonium, dimethylammonium, trimethylammonium, ethylammonium, diethylammonium, triethylammonium, methylethylammonium, diethylmethylammonium, dimethylethylammonium, propylammonium, dipropylammonium, isopropylammonium, and diisopropyl. Ammonium, butylammonium, dibutylammonium, methylpropylammonium, ethylpropylammonium, methylisopropylammonium, ethylisopropylammonium, methylbutylammonium, ethylbutylammonium, tetramethylammonium, tetramethylolammonium, tetraethylammonium, tetran-butylammonium, tetra Examples thereof include sec-butylammonium and tetrat-butylammonium.
Examples of the saturated alicyclic ammonium salt include piperidinium, pyrrolidinium, morpholinium, piperadinium, and derivatives having a skeleton thereof.
Examples of the unsaturated alicyclic ammonium salt include pyridinium, α-picolinium, β-picolinium, γ-picolinium, quinolinium, isoquinolinium, pyrrolinium, and derivatives having a skeleton thereof.

In the formula (1), one of R ^{1 to} R ⁵ is a linear or branched alkoxy group having 1 to 4 carbon atoms, and the other one is an acidic group because it is easy to produce. It is preferable that the rest is a hydrogen atom.
From the viewpoint of easy production, it is more preferable that either one of R ¹ and R ² is an acidic group and one of R ⁴ and R ⁵ is an alkoxy group.
The acidic group is more preferably a sulfonic acid group.

Compound (1) is a compound (2-aminoanisole-4) in which R ¹ , R ³ , and R ⁴ are hydrogen atoms, R ² is a sulfonic acid group, and R ⁵ is a methoxy group in the formula (1). -Sulfonic acid), or a salt thereof.

The conductive polymer (A) may contain a structural unit based on a compound other than the compound (1) as long as it does not affect the solubility, conductivity and properties.
The other compound may be a monomer copolymerizable with the compound (1), and examples thereof include substituted or unsubstituted aniline (excluding the compound (1)), thiophene, pyrrole, phenylene, vinylene and the like.

From the viewpoint of excellent solubility in water and organic solvents regardless of pH, the conductive polymer (A) has a constituent unit (1) with respect to all the constituent units (100 mol%) of the conductive polymer (A). The content is preferably 10 to 100 mol%, more preferably 50 to 100 mol%, and particularly preferably 100 mol%.
Further, the conductive polymer (A) preferably contains 10 or more structural units (1) in one molecule from the viewpoint of excellent conductivity.

The conductive polymer (A) is preferably a compound having a structure represented by the following general formula (2), and is represented by the following general formula (2), from the viewpoint of exhibiting high conductivity and solubility. Among the compounds having such a structure, poly (2-sulfo-5-methoxy-1,4-iminophenylene) is particularly preferable.

In formula (2), R ^{12 to} R ²⁷ are independently hydrogen atoms, linear or branched alkyl groups having 1 to 4 carbon atoms, and linear or branched alkoxy groups having 1 to 4 carbon atoms. Represents an acidic group, a hydroxy group, a nitro group, or a halogen atom (-F, -Cl, -Br or I). Further, at least one of R ^{12 to} R ²⁷ is an acidic group or a salt thereof. Further, n indicates the degree of polymerization. n is preferably an integer of 5 to 2500.

It is desirable that at least a part of the acidic group contained in the conductive polymer (A) is a free acid type from the viewpoint of improving conductivity.

The mass average molecular weight of the conductive polymer (A) is preferably 10 to 1,000,000, more preferably 1,500 to 800,000, and more preferably 2,000, in terms of sodium polystyrene sulfonate of GPC, from the viewpoint of conductivity, solubility and film forming property. ~ 500,000 is more preferable, and 20 to 100,000 is particularly preferable. When the mass average molecular weight of the conductive polymer (A) is less than 1000, the solubility is excellent, but the conductivity and the film-forming property may be insufficient. On the other hand, when the mass average molecular weight exceeds 1 million, the conductivity may be excellent, but the solubility may be insufficient.
Here, the "film-forming property" refers to the property of forming a uniform film without repellency and the like, and can be evaluated by a method such as spin coating on glass.

(Physical properties)
The conductive polymer (A) of the present embodiment satisfies the following condition 1.
Condition 1: The area ratio (X / Y) calculated by the evaluation method including the following steps (I) to (VI) is 0.05 to 0.3.
(I) A step of preparing a test solution by dissolving the conductive polymer (A) in an eluent having a pH of 10 or more so that the solid content concentration of the conductive polymer (A) is 0.1% by mass.
(II) A step of measuring the molecular weight distribution of a test solution using a polymer material evaluation device equipped with a gel permeation chromatograph to obtain a chromatogram.
(III) A step of converting the retention time of the chromatogram obtained in step (II) into the molecular weight (M) in terms of sodium polystyrene sulfonate.
(IV) A step of determining the area (X) of a region having a molecular weight (M) of 1000 or less in the chromatogram obtained in step (III).
(V) A step of determining the area (Y) of the entire region derived from the conductive polymer (A) in the chromatogram obtained in the step (III).
(VI) A step of obtaining an area ratio (X / Y) of an area (X) and an area (Y).

The step (I) is a step of preparing a test solution by dissolving the conductive polymer (A) in an eluent so that the solid content concentration of the conductive polymer (A) is 0.1% by mass.
The eluent is a solution in which a solute is dissolved in a solvent. Examples of the solvent include water, acetonitrile, alcohol (methanol, ethanol, etc.), dimethylformamide, dimethyl sulfoxide, and a mixed solvent thereof.
Examples of the solute include sodium carbonate, sodium hydrogen carbonate, sodium dihydrogen phosphate, trisodium phosphate, disodium hydrogen phosphate, glycine, sodium hydroxide, potassium chloride, boric acid and the like.

The pH of the eluent used in step (I) is 10 or more. If the pH is less than 10, the quantitative value may fluctuate. Stable measurement results can be obtained by using an eluent having a pH of 10 or more.
An eluent having a pH of 10 or higher can be prepared, for example, as follows.
First, water (ultrapure water) and methanol are mixed so that the volume ratio is water: methanol = 8: 2 to obtain a mixed solvent. Then, sodium carbonate and sodium hydrogen carbonate are added to the obtained mixed solvent so that the solid content concentrations are 20 mmol / L and 30 mmol / L, respectively, to obtain an eluent.
The eluent thus obtained has a pH of 10.8 at 25 ° C.
The pH of the eluent is a value measured using a pH meter while the temperature of the eluent is maintained at 25 ° C.

The method for preparing an eluent having a pH of 10 or more is not limited to the above method, and for example, a mixed solvent of water and methanol (water: methanol = 8: 2) is used to prepare an eluent having a solid content concentration of 20 mmol / L with sodium carbonate. , Sodium hydrogen carbonate having a solid content concentration of 30 mmol / L may be prepared separately and mixed to prepare an eluent.

Step (II) is a step of measuring the molecular weight distribution of the test solution by gel permeation chromatography (GPC) using a polymer material evaluation device.
The polymer material evaluation device is equipped with a gel permeation chromatograph, and can separate and analyze compounds (polymers, oligomers, monomers) according to the size of the molecular weight.
Detectors such as a photodiode array detector and a UV detector are connected to the gel permeation chromatograph.
In step (II), GPC gives, for example, a chromatogram as shown in FIG.
In the chromatogram shown in FIG. 1, the vertical axis represents the absorbance and the horizontal axis represents the retention time, the high molecular weight component is detected with a relatively short retention time, and the low molecular weight component is detected with a relatively long retention time.

The step (III) is a step of converting the retention time of the chromatogram obtained in the step (II) into the molecular weight (M) in terms of sodium polystyrene sulfonate.
Specifically, sodium polystyrene sulfonate having a peak top molecular weight of 206, 1030, 4210, 13500, 33500, 78400, 158000, 2350,000 was used as a standard sample, and each standard sample had a solid content concentration in the same manner as the test solution. A standard solution is prepared by dissolving only a standard sample having a peak top molecular weight of 206 by 0.05% by mass in an eluent so that the solid content concentration is 0.0025% by mass. Then, the relationship between the retention time and the molecular weight is obtained by GPC for each standard solution, and a calibration curve is prepared. From the prepared calibration curve, the retention time of the chromatogram obtained in step (II) is converted to the molecular weight (M) in terms of sodium polystyrene sulfonate.
For example, in the example of FIG. 1, the molecular weight (M) corresponding to the holding time of 27.1 minutes is 10000, and the molecular weight corresponding to the holding time of 31.0 minutes is 1000.

The step (IV) is a step of determining the area (X) of the region having a molecular weight (M) of 1000 or less in the chromatogram.
Further, the step (V) is a step of determining the area (Y) of the entire region derived from the conductive polymer (A) in the chromatogram.
The step (VI) is a step of obtaining an area ratio (X / Y) of an area (X) and an area (Y).

The conductive polymer (A) of the present embodiment has a molecular weight (M) with respect to the area ratio (X / Y) calculated by the above-mentioned evaluation method, that is, the area (Y) of the entire region derived from the conductive polymer (A). ) Is 1000 or less, and the ratio of the area (X) is 0.05 to 0.3. The area ratio (X / Y) is an index of the content ratio of molecules having a molecular weight (M) of 1000 or less with respect to the total amount of the conductive polymer (A).
When the area ratio (X / Y) is 0.3 or less, the surface smoothness when the coating film is formed is excellent, and when it is 0.05 or more, the conductivity of the conductive film is excellent. The area ratio (X / Y) is preferably 0.06 to 0.2.

The area (X) is the area of a region having a molecular weight (M) of 1000 or less, and it is considered that the low molecular weight component existing in this region contributes to the improvement of surface smoothness. On the other hand, such low molecular weight components include oligomers, acidic substances, basic substances (such as basic reaction aids and ammonium ions which are decomposition products of oxidizing agents) that accompany the occurrence of side reactions during the production of conductive polymers. Are included, and these components are factors that inhibit conductivity.

In order to obtain a conductive polymer having an area ratio (X / Y) of 0.05 to 0.3, for example, in the production of the conductive polymer, a step of purifying the reaction product is provided, and a low molecular weight component is appropriately added. It is preferable to remove it.

<Manufacturing method of conductive polymer (A)>
The method for producing the conductive polymer (A) of the present embodiment includes a step (polymerization step) of polymerizing a raw material monomer containing the compound (1) in the presence of a polymerization solvent and an oxidizing agent, and a reaction generation obtained in the polymerization step. Includes a step of refining a product (purification step).
In addition to the compound (1), the raw material monomer may contain one or more other compounds copolymerizable with the compound (1).

Examples of the polymerization solvent include water, an organic solvent, and a mixed solvent of water and an organic solvent. Examples of the organic solvent 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 glycol and propylene glycol. Propropylene glycols such as 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; N-methylpyrrolidone, N-ethylpyrrolidone and the like. Pyrrolidones and the like.
As the polymerization solvent, water or a mixed solvent of water and an organic solvent is preferable.

The oxidizing agent is not limited as long as it has a standard electrode potential of 0.6 V or more, but peroxodisulfates such as peroxodisulfuric acid, ammonium peroxodisulfate, sodium peroxodisulfate, and potassium peroxodisulfate; Examples include hydrogen peroxide.
Any one of these oxidizing agents may be used alone, or two or more thereof may be mixed and used at an arbitrary ratio.

In the polymerization step, the raw material monomer may be polymerized in the presence of a basic reaction aid in addition to the polymerization solvent and the oxidizing agent.
Examples of the basic reaction aid include inorganic bases such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; ammonia; methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylmethylamine, ethyldimethylamine, diethyl. Fatty amines such as methylamine; cyclic saturated amines; cyclic unsaturated amines such as pyridine, α-picoline, β-picoline, γ-picoline and quinoline can be mentioned.
Among these, inorganic bases, aliphatic amines and cyclic unsaturated amines are preferable, and cyclic unsaturated amines are more preferable.
Any one of these basic reaction aids may be used alone, or two or more thereof may be mixed and used in an arbitrary ratio.

Examples of the polymerization method include a method of dropping the raw material monomer solution into the oxidizing agent solution, a method of dropping the oxidizing agent solution into the raw material monomer solution, and a method of dropping the raw material monomer solution and the oxidizing agent solution into a reaction vessel or the like at the same time. And so on. The raw material monomer solution may contain a basic reaction aid, if necessary.
As the solvent of the oxidizing agent solution and the raw material monomer solution, the above-mentioned polymerization solvent can be used.

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. When the reaction temperature of the polymerization reaction is 50 ° C. or lower, particularly 30 ° C. or lower, it is possible to suppress a decrease in conductivity due to the progress of side reactions and changes in the redox structure of the main chain of the conductive polymer (A) to be produced. When the reaction temperature of the polymerization reaction is −15 ° C. or higher, a sufficient reaction rate can be maintained and the reaction time can be shortened.

By the polymerization step, the conductive polymer (A) which is a reaction product is obtained in a state of being dissolved or precipitated in a 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 by a filter such as a centrifuge to obtain a reaction product.

(Refining process)
The reaction product obtained in the polymerization step is purified so that the area ratio (X / Y) is 0.05 to 0.3 to obtain a refined product.
As a method for purifying the reaction product, known methods such as a washing method using a washing solvent, a membrane filtration method, an ion exchange method, removal of impurities by heat treatment, and neutralization precipitation can be used. Two or more purification methods may be combined.

As a method for purifying the reaction product, for example, the following methods (1) to (3) can be used.
Method (1): A method of washing the reaction product with a washing solvent to remove low molecular weight components.
Examples of the washing solvent include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-butanol, 3-butanol, t-butanol, 1-pentanol, 3-methyl-1-butanol, 2-. Alcohols such as pentanol, n-hexanol, 4-methyl-2-pentanol, 2-ethylbutinol, benzyl alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methoxy Polyhydric alcohol derivatives such as methoxyethanol, propylene glycol monoethyl ether and glyceryl monoacetate; acetone; acetonitrile; N, N-dimethylformamide; N-methylpyrrolidone; dimethylsulfoxide and a mixed solvent thereof with water and the like can be mentioned. Among these, a mixed solvent of methanol, ethanol, isopropanol, acetone, acetonitrile and water thereof is effective.

Method (2): A method in which a reaction product is dissolved in water and then filtered to remove water-insoluble low molecular weight components. The aqueous solution of the refined product (conductive polymer (A)) obtained as the filtrate can be used as it is as the conductive composition. Alternatively, it may be dried to obtain a solid conductive polymer (A).
As the filtration membrane, a permeable membrane is preferable, and a microfiltration membrane and an ultrafiltration membrane are particularly preferable.

Examples of the material of the microfiltration membrane include polyethylene (PE), ethylene tetrafluoride (PTFE), polypropylene (PP), cellulose acetate (CA), polyacrylonitrile (PAN), polyimide (PI), polysulfone (PS), and the like. Examples thereof include organic films such as polyethersulfone (PES) and nylon (Ny). Nylon and polyethylene are particularly preferable from the viewpoint of excellent solvent resistance.
The filter structure of the microfiltration membrane is not particularly limited as long as it is used as a material for a normal microfiltration membrane, and examples thereof include a flat membrane pleated type and a hollow fiber type.

The material of the ultrafiltration membrane is not particularly limited as long as it is used as the material of an ordinary ultrafiltration membrane, but for example, cellulose, cellulose acetate, polysulfone, polypropylene, polyester, polyethersulfone, and polyvinylidene fluoride. Examples thereof include an organic membrane such as vinylidene, an inorganic membrane such as ceramics, and an organic-inorganic hybrid membrane. In particular, a ceramic film is preferable from the viewpoint of excellent solvent resistance and easy maintenance such as chemical cleaning.
The larger the value of the fractionated molecular weight of the ultrafiltration membrane, the higher the critical permeation flux, and the more conductive the conductive composition obtained after purification tends to be, but the yield tends to decrease. ..
Similarly, as the value of the pore size of the ultrafiltration membrane increases, the critical permeation flux increases, and the conductivity of the conductive composition obtained after purification tends to increase, but the yield tends to decrease.

When the unpurified mixed solution is purified by the membrane filtration method, the filtration pressure is preferably about 0.01 to 1.0 MPa in consideration of productivity, although it depends on the ultrafiltration membrane and the filtration device.
The filtration time is not particularly limited, but if other conditions are the same, the longer the time, the higher the degree of purification.

Method (3): A method of removing low molecular weight components in the reaction product by dissolving the reaction product in a good solvent and then recrystallizing by adding a poor solvent.
Examples of a good solvent include a polymerization solvent described later.
Examples of the poor solvent include ketones, alcohols, acetonitrile and the like.

<Action effect>
Since the conductive polymer (A) of the present invention contains a low molecular weight component having a molecular weight (M) of 1000 or less in a specific ratio, it is excellent in surface smoothness when forming a conductive film and is good in the conductive film. Conductivity is also obtained.

[Conductive composition]
The conductive composition contains the above-mentioned conductive polymer (A) of the present invention and a solvent (B). The conductive composition may contain a basic compound (C), a surfactant (D) and the like, if necessary.

<Conductive polymer (A)>
The conductive polymer (A) is the conductive polymer (A) of the present invention described above, and the description thereof will be omitted.
The content of the conductive polymer (A) is preferably 0.1 to 5% by mass, more preferably 0.2 to 3% by mass, and 0.5 to 2% by mass with respect to the total mass of the conductive composition. Is even more preferable.
The content of the conductive polymer (A) is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, and 95 to 100% by mass with respect to the total mass of the solid content of the conductive composition. More preferred. The solid content of the conductive composition is the residue obtained by removing the solvent (B) from the conductive composition.
When the content of the conductive polymer (A) is within the above range, the balance between the coatability of the conductive composition and the conductivity of the coating film formed from the conductive composition is excellent.

<Solvent (B)>
The solvent (B) is particularly limited as long as it has the effect of the present invention as long as it is a solvent capable of dissolving the conductive polymer (A) and the basic compound (C) and the surfactant (D) described later. Although not removed, water, organic solvents, and mixed solvents of water and organic solvents can be mentioned.
Examples of water include tap water, ion-exchanged water, pure water, distilled water and the like.
Examples of the organic solvent include organic solvents among the polymerization solvents exemplified above in the description of the method for producing the conductive polymer (A).
When a mixed solvent of water and an organic solvent is used as the solvent (B), the mass ratio (water / organic solvent) of these is preferably 1/100 to 100/1, and 2/100 to 100/2. More preferably.

The content of the solvent (B) is preferably 1 to 99.9% by mass, more preferably 10 to 98% by mass, still more preferably 50 to 98% by mass, based on the total mass of the conductive composition. When the content of the solvent (B) is within the above range, the coatability is further improved.
When the conductive polymer (A) is used in a state of being dissolved in an aqueous medium by purification or the like (hereinafter, the conductive polymer (A) in this state is also referred to as a "conductive polymer solution"), the conductive polymer An aqueous medium derived from the solution is also included in the content of the solvent (B) in the conductive composition.

<Basic compound (C)>
The conductive composition may contain the basic compound (C).
When the conductive composition contains the basic compound (C), the basic compound (C) efficiently acts on the acidic groups in the conductive polymer (A) to form a salt, thereby forming the conductive polymer. It is considered that the stability of (A) can be improved. As a result, a network structure is likely to be formed, a current is likely to flow uniformly through the conductive film, and the conductivity becomes more uniform.

The basic compound (C) is not particularly limited as long as it is a compound having basicity, and for example, the following quaternary ammonium salt (c-1), basic compound (c-2), and basic compound (c) are used. -3) and the like.
Quadruple ammonium salt (c-1): A quaternary ammonium compound in which at least one of the four substituents bonded to the nitrogen atom is a hydrocarbon group having 3 or more carbon atoms.
Basic compound (c-2): A basic compound having one or more nitrogen atoms (excluding the quaternary ammonium salt (c-1) and the basic compound (c-3)).
Basic compound (c-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.

In the quaternary ammonium compound (c-1), the nitrogen atom to which the four substituents are bonded is the nitrogen atom of the quaternary ammonium ion.
In the quaternary ammonium compound (c-1), examples of the hydrocarbon group bonded to the nitrogen atom of the quaternary ammonium ion include an alkyl group, an aralkyl group, an aryl group and the like.
Examples of the quaternary ammonium compound (c-1) include tetrapropyl ammonium hydroxide, tetrabutyl ammonium hydroxide, tetrapentyl ammonium hydroxide, tetrahexyl ammonium hydroxide, and benzyl trimethyl ammonium hydroxide.

Examples of the basic compound (c-2) include ammonia, pyridine, triethylamine, 4-dimethylaminopyridine, 4-dimethylaminomethylpyridine, 3,4-bis (dimethylamino) pyridine, and 1,5-diazabicyclo [4]. .3.0] -5-nonen (DBN), 1,8-diazabicyclo [5.4.0] -7-undecene (DBU), and derivatives thereof.

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

Any one of these basic compounds may be used alone, or two or more thereof may be mixed and used in an arbitrary ratio.
Among these, at least one selected from the group consisting of a quaternary ammonium salt (c-1) and a basic compound (c-2) because it easily forms a salt with an acidic group of the conductive polymer (A). Is preferably included.

From the viewpoint of further improving the coatability of the conductive composition, the content of the basic compound (C) is set to 0, with respect to 1 mol of the unit having an acidic group among the units constituting the conductive polymer (A). The equivalent of 1 to 1 mol is preferable, and the equivalent of 0.1 to 0.9 mol is more preferable. Further, 0.25 to 0.85 mol equivalent is particularly preferable from the viewpoint of excellent retention of performance as a conductive film and more stable acidic groups in the conductive polymer (A).

<Surfactant (D)>
The conductive composition may contain a surfactant (D).
When the conductive composition contains the surfactant (D), the coatability when the conductive composition is applied to the surface of the base material or the resist layer is improved.
Examples of the surfactant include anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants and the like. Any one of these surfactants may be used alone, or two or more of these surfactants may be mixed and used in an arbitrary ratio.

Examples of anionic surfactants include sodium octanate, sodium decanoate, sodium laurate, sodium myristate, sodium palmitate, sodium stearate, perfluorononanoic acid, sodium N-lauroyl sarcosinate, sodium cocoyl glutamate, and alpha. Examples thereof include sulfo fatty acid methyl ester salt, sodium lauryl sulfate, sodium myristyl sulfate, sodium laureth sulfate, sodium polyoxyethylene alkylphenol sulfonate, ammonium lauryl sulfate, lauryl phosphate, sodium lauryl phosphate, and potassium lauryl phosphate.

Examples of cationic surfactants include tetramethylammonium chloride, tetramethylammonium hydroxide, tetrabutylammonium chloride, dodecyldimethylbenzylammonium chloride, alkyltrimethylammonium chloride, octyltrimethylammonium chloride, decyltrimethylammonium chloride, and dodecyl chloride. Trimethylammonium, tetradecyltrimethylammonium chloride, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, alkyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzalkonium chloride, benzal bromide Luconium, benzethonium chloride, dialkyldimethylammonium chloride, didecyldimethylammonium chloride, distearyldimethylammonium chloride, monomethylamine hydrochloride, dimethylamine hydrochloride, trimethylamine hydrochloride, butylpyridinium chloride, dodecylpyridinium chloride, cetylpyridinium chloride, etc. Can be mentioned.

Examples of the amphoteric surfactant include lauryldimethylaminoacetic acid betaine, stearyldimethylaminoacetic acid betaine, dodecylaminomethyldimethylsulfopropyl betaine, octadecylaminomethyldimethylsulfopropyl betaine, cocamidopropyl betaine, cocamidopropyl hydroxysultaine, 2 Examples thereof include -alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, sodium lauroyl glutamate, potassium lauroyl glutamate, lauroylmethyl-β-alanine, lauryldimethylamine-N-oxide, and oleyldimethylamine N-oxide. ..

Examples of the nonionic surfactant include glycerin laurate, glycerin monostearate, sorbitan fatty acid ester, sucrose fatty acid ester, polyoxyethylene alkyl ether, pentaethylene glycol monododecyl ether, octaethylene glycol monododecyl ether, and poly. Oxyethylene alkylphenyl ether, octylphenol ethoxylate, nonylphenol ethoxylate, polyoxyethylene polyoxypropylene glycol, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene hexitan fatty acid ester, sorbitan fatty acid ester polyethylene glycol, laurate diethanolamide, oleic acid Examples thereof include diethanolamide, stearic acid diethanolamide, octyl glucoside, decyl glucoside, lauryl glucoside, cetanol, stearyl alcohol and oleyl alcohol.

In addition to the above, a water-soluble polymer having a nitrogen-containing functional group and a terminal hydrophobic group may be used as the nonionic surfactant. Unlike conventional surfactants, this water-soluble polymer has a surface-active ability due to a main chain portion (hydrophilic portion) having a nitrogen-containing functional group and a hydrophobic group portion at the end, and has an effect of improving coatability. Is high. Therefore, excellent coatability can be imparted to the conductive composition without using other surfactants in combination. Moreover, since this water-soluble polymer does not contain acids and bases and is unlikely to generate by-products due to hydrolysis, it has little adverse effect on the resist layer and the like.

As the nitrogen-containing functional group, an amide group is preferable from the viewpoint of solubility.
Examples of the terminal hydrophobic group include an alkyl group, an aralkyl group, an aryl group, an alkoxy group, an aralkyloxy group, an aryloxy group, an alkylthio group, an aralkylthio group, an arylthio group, a primary or secondary alkylamino group, and an aralkylamino group. , Arylamino group and the like. Among these, an alkylthio group, an aralkylthio group and an arylthio group are preferable.
The number of carbon atoms of the terminal hydrophobic group is preferably 3 to 100, more preferably 5 to 50, and particularly preferably 7 to 30.
The number of terminal hydrophobic groups in the water-soluble polymer is not particularly limited. Further, when two or more terminal hydrophobic groups are contained in the same molecule, the terminal hydrophobic groups may be of the same type or different types.

The water-soluble polymer is mainly 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 having no nitrogen-containing functional group (other vinyl monomers). A compound having a chain structure and having a hydrophobic group at a site other than the repeating unit constituting the polymer is preferable.
Examples of the vinyl monomer having a nitrogen-containing functional group include acrylamide and its derivatives, a heterocyclic monomer having a nitrogen-containing functional group, and the like, and among them, those having an amide bond are preferable. Specifically, acrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, N, N-diethylacrylamide, N, N-dimethylaminopropylacrylamide, t-butylacrylamide, diacetoneacrylamide, N, N'-methylene Examples thereof include bisacrylamide, N-vinyl-N-methylacrylamide, N-vinylpyrrolidone, and N-vinylcaprolactam. Among these, acrylamide, N-vinylpyrrolidone, N-vinylcaprolactam and the like are particularly preferable from the viewpoint of solubility.
The other vinyl monomer is not particularly limited as long as it can copolymerize a vinyl monomer having a nitrogen-containing functional group, and examples thereof include styrene, acrylic acid, vinyl acetate, and long-chain α-olefins.

The method for introducing the terminal hydrophobic group into the water-soluble polymer is not particularly limited, but it is usually convenient and preferable to introduce it by selecting a chain transfer agent at the time of vinyl polymerization. In this case, as the chain transfer agent, if 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 is introduced into the terminal of the obtained polymer. There is no particular limitation. For example, when a water-soluble polymer having an alkylthio group, an aralkylthio group, or an arylthio group is obtained as a terminal hydrophobic group, a chain transfer agent having a hydrophobic group corresponding to these terminal hydrophobic groups, specifically, a thiol , Disulfide, thioether and the like are preferably used for vinyl polymerization.

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) of the main chain portion is preferably 2 to 1000, more preferably 3 to 1000, and particularly preferably 5 to 10 in one molecule. If the number of units of the main chain portion having a nitrogen-containing functional group is too large, the surface activity tends to decrease.
Molecular weight ratio (mass average of main chain portion) of main chain moiety in water-soluble polymer to terminal hydrophobic group moiety (for example, alkyl group, aralkyl group, aryl group, alkylthio group, aralkylthio group, arylthio group, etc.) The molecular weight / mass average molecular weight of the terminal hydrophobic group portion) is preferably 0.3 to 170.

As the surfactant (D), a nonionic surfactant is preferable because it has little effect on the resist layer among the above-mentioned ones.

The content of the surfactant (D) is preferably 5 to 80 parts by mass when the total of the conductive polymer (A), the basic compound (C) and the surfactant (D) is 100 parts by mass. 10 to 70 parts by mass is more preferable, and 10 to 60 parts by mass is further preferable. When the content of the surfactant (D) is within the above range, the applicability of the conductive composition to the resist layer is further improved.

<Arbitrary ingredient>
The conductive composition may contain components (arbitrary components) other than the conductive polymer (A), the solvent (B), the basic compound (C) and the surfactant (D), if necessary.
Examples of the optional component include a polymer compound (excluding the conductive polymer (A), the basic compound (C) and the surfactant (D)), an additive and the like.

Examples of the polymer compound include polyvinyl alcohol derivatives such as polyvinyl formal and polyvinyl butyral, polyacrylamides such as polyacrylamide, poly (Nt-butylacrylamide), and polyacrylamide methylpropanesulfonic acid, polyvinylpyrrolidone, and poly. Acrylic acids, water-soluble alkyd resin, water-soluble melamine resin, water-soluble urea resin, water-soluble phenol resin, water-soluble epoxy resin, water-soluble polybutadiene resin, water-soluble acrylic resin, water-soluble urethane resin, water-soluble acrylic styrene copolymer Examples thereof include 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 the additive include pigments, antifoaming agents, ultraviolet absorbers, antioxidants, heat resistance improvers, leveling agents, anti-dripping agents, matting agents, preservatives and the like.

<Method for producing conductive composition>
The conductive composition is a mixture of the conductive polymer (A) of the present invention, a solvent (B), and if necessary, a basic compound (C), a surfactant (D), and one or more of optional components. Obtained by doing.
The conductive polymer (A) obtained in a solid state and the solvent (B) may be mixed to prepare a conductive polymer solution, and the obtained conductive polymer solution may be used as the conductive composition. Further, if necessary, one or more of the basic compound (C), the surfactant (D) and an optional component may be added to the conductive polymer solution to obtain a conductive composition.
The conductive polymer solution obtained in the form of a solution may be used as it is as a conductive composition, or may be further diluted with a solvent (B). Further, if necessary, one or more of the basic compound (C), the surfactant (D) and an optional component may be added to the conductive polymer solution to obtain a conductive composition.

<Action effect>
Since the conductive composition of the present invention contains the conductive polymer (A) containing a low molecular weight component having a molecular weight (M) of 1000 or less in a specific ratio, it is excellent in surface smoothness when forming a conductive film. , Good conductivity in conductive film can also be obtained.

<Use>
The conductive composition of the present invention is suitable for antistatic use when drawing a charged particle beam. Specifically, the conductive composition of the present invention is applied to the surface of a resist layer of a pattern forming method using a charged particle beam using a 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 the present invention can also be used as a material for, for example, a capacitor, a transparent electrode, a semiconductor, or the like.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples do not limit the scope of the present invention.
The various measurement / evaluation methods in Examples and Comparative Examples are as follows.

[Measurement / evaluation method]
<Calculation of area ratio (X / Y)>
First, sodium carbonate and sodium hydrogen carbonate are mixed in a mixed solvent in which water (ultrapure water) and methanol are mixed so that the volume ratio is water: methanol = 8: 2, and the solid content concentration of each is 20 mmol / L. An eluent was prepared by adding to 30 mmol / L. The resulting eluent had a pH of 10.8 at 25 ° C.
A test solution was prepared by dissolving the conductive polymer (A) in this eluent so that the solid content concentration of the conductive polymer (A) was 0.1% by mass (step (I)).
For the obtained test solution, a polymer material evaluation device (Waters, "Waters Alliance 2695, 2414 (refractive index meter)), 2996 (manufactured by Waters), equipped with a gel permeation chromatograph to which a photodiode array (PDA) detector is connected. The molecular weight distribution was measured using PDA) ”) to obtain a chromatogram (step (II)).
Then, with respect to the obtained chromatogram, the retention time was converted into the molecular weight (M) in terms of sodium polystyrene sulfonate (step (III)). Specifically, sodium polystyrene sulfonate having a peak top molecular weight of 206, 4300, 6800, 17000, 32000, 77000, 15000, 2600000 was used as a standard sample, and each standard sample had a solid content concentration in the same manner as the test solution. A standard solution was prepared by dissolving the standard sample having a peak top molecular weight of 206 so as to have a solid content concentration of 0.0025% by mass so as to be 0.05% by mass. Then, the relationship between the retention time and the molecular weight was determined by GPC for each standard solution, and a calibration curve was prepared. From the prepared calibration curve, the retention time of the chromatogram obtained in step (II) was converted to the molecular weight (M) in terms of sodium polystyrene sulfonate.
Then, the area (X) of the region having a molecular weight (M) of 1000 or less and the area (Y) of the entire region derived from the conductive polymer (A) were determined (steps (IV) and (V)).
The area ratio (X / Y) of these areas (X) to the area (Y) was determined (step (VI)).

<Evaluation of conductivity>
2.0 mL of the conductive composition was dropped onto a glass base material as a base material, and the coating film was formed by rotating and coating with a spin coater under the conditions of 2000 rpm × 60 seconds so as to cover the entire surface of the base material. Heat treatment was performed at 80 ° C. for 2 minutes on a hot plate to form a conductive film having a film thickness of about 30 nm on the substrate to obtain a conductor.
The surface resistance value [Ω / □] of the conductive film was measured by the two-terminal method (distance between electrodes 20 mm) using Hiresta UX-MCP-HT800 (manufactured by Mitsubishi Chemical Analytech Co., Ltd.).

<Evaluation of surface smoothness>
The arithmetic mean roughness (Ra) of the coating film (conductive film) was measured using a scanning probe microscope (“SPI4000 / SPA400” manufactured by Seiko Instruments Inc.) under the following measurement conditions.
<< Measurement conditions >>
・ Cantilever: SI-DF20
-Measurement mode: Tapping mode-Scanning range: 1 μm x 1 μm
・ Scanning speed: 0.6Hz

<Example 1>
[Manufacturing of conductive polymer (A)]
To 100 mmol of 2-aminoanisole-4-sulfonic acid, 100 mmol of pyridine and 100 mL of water were added to obtain a monomer solution.
An aqueous solution of 100 mmol of ammonium peroxodisulfate (oxidizing agent solution) was added dropwise to the obtained monomer solution at 10 ° C. After completion of the dropping, the mixture was further stirred at 25 ° C. for 15 hours, then heated to 35 ° C. and further stirred for 2 hours to obtain a reaction solution in which the reaction product was precipitated (polymerization step).
The obtained reaction solution is filtered through a centrifugal filter, the precipitate (reaction product) is collected, the reaction product is washed with 1 L of methanol, and then dried to obtain a powdery conductive polymer (A1). Was obtained (purification step).
The amount of methanol used in the purification step corresponds to 5000 parts by mass with respect to 100 parts by mass of the conductive polymer (A1).
The area ratio (X / Y) of the conductive polymer (A1) in the chromatogram was measured by the above method. Table 1 shows the measurement results of the mass average molecular weight and the area ratio (X / Y) of the conductive polymer (A1) (the same applies hereinafter).

[Preparation of conductive composition]
2 parts by mass of the conductive polymer (A1), 93.1 parts by mass of water, and 4.9 parts by mass of isopropyl alcohol (IPA) were mixed to obtain a conductive composition.
With respect to the obtained conductive composition, a conductive film was formed by the above method, and the conductivity and surface smoothness were evaluated. The results are shown in Table 1 (the same applies hereinafter).

<Example 2>
In Example 1, a powdery conductive polymer (A2) was obtained in the same manner as in Example 1 except that 1 L of ethanol was used instead of 1 L of methanol as a washing solvent.

<Comparative example 1>
In Example 1, the reaction product was not washed. Other than that, a powdery conductive polymer (A3) was obtained in the same manner as in Example 1.

<Comparative example 2>
The conductive polymer obtained in Example 1 was used as a 1% aqueous solution and purified by limit filtration having a molecular weight cut off of 50,000 daltons to obtain an aqueous conductive polymer (A4).

As shown in Table 1, the conductive polymers of Examples 1 and 2 in which the reaction products were appropriately washed had an area ratio (X / Y) in the range of 0.05 to 0.3 and a molecular weight (molecular weight). M) contains a small amount of low molecular weight components of 1000 or less. The conductive film formed by using the conductive polymers of Examples 1 and 2 had a small arithmetic mean roughness (Ra) of the conductive film, excellent surface smoothness, a small surface resistance value, and good conductivity. ..
The conductive polymer of Comparative Example 1 in which the reaction product was not washed contains a large amount of low molecular weight components having an area ratio (X / Y) of more than 0.3 and a molecular weight (M) of 1000 or less. Compared with Examples 1 and 2, the surface resistance value was large and the conductivity was inferior.
The conductive polymer of Comparative Example 2 in which the washing conditions of the reaction product were changed has an area ratio (X / Y) smaller than 0.05 and extremely few low molecular weight components having a molecular weight (M) of 1000 or less. The surface smoothness was inferior to that of Examples 1 and 2.

The conductive polymer of the present invention is excellent in surface smoothness and conductivity when formed into a coating film (conductive film), and is useful for antistatic use when drawing charged particle beams.

Claims (4)

It has a structural unit based on the compound (1) represented by the following formula (1).
A conductive polymer having an area ratio (X / Y) of 0.05 to 0.3 calculated by an evaluation method including the following steps (I) to (VI).
(I) A step of preparing a test solution by dissolving the conductive polymer in an eluent having a pH of 10 or more so that the solid content concentration of the conductive polymer is 0.1% by mass.
(II) A step of measuring the molecular weight distribution of the test solution using a polymer material evaluation device equipped with a gel permeation chromatograph to obtain a chromatogram.
(III) A step of converting the retention time of the chromatogram obtained in the step (II) into a molecular weight (M) in terms of sodium polystyrene sulfonate.
(IV) A step of determining the area (X) of a region having a molecular weight (M) of 1000 or less in the chromatogram obtained in the step (III).
(V) A step of determining the area (Y) of the entire region derived from the conductive polymer in the chromatogram obtained in the step (III).
(VI) A step of obtaining an area ratio (X / Y) of the area (X) and the area (Y).

(In the formula, R ^{1 to} R ⁵ are independently hydrogen atoms, linear or branched alkyl groups having 1 to 24 carbon atoms, linear or branched alkoxy groups having 1 to 24 carbon atoms, acidic groups, and the like. It is a hydroxy group, a nitro group, or a halogen atom (-F, -Cl, -Br or I), and at least one of R ^{1 to} R ⁵ is a hydrogen atom, at least one is an alkoxy group, and at least one. Is an acidic group.) The conductive polymer according to claim 1, wherein at least one of R ^{1 to} R ⁵ is a methoxy group. The conductive polymer according to claim 1 or 2, which is used for preventing static electricity when drawing a charged particle beam. A conductive composition containing the conductive polymer according to any one of claims 1 to 3 and a solvent.

Images