JP2011219680A - Method for producing conductive resin composition and conductive resin composition obtained by the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a conductive resin composition having little fluctuation in sensitivity and enabling formation of a preferable pattern feature, and to provide a conductive resin composition obtained by the method.SOLUTION: The method for producing a conductive resin composition includes: a first step of polymerizing an acidic group-substituted aniline with an oxidizing agent in the presence of a basic reaction aid to obtain a conductive resin; a second step of removing a basic substance from the reaction mixture containing the obtained conductive resin; and a third step of further adding a basic additive to the reaction mixture. The conductive resin composition is obtained by the method.

Description

  The present invention relates to a method for producing a conductive resin composition, and a conductive resin composition obtained therefrom.

A pattern forming technique using charged particle beams such as an electron beam and an ion beam is expected as a next generation technique of optical lithography.
In the method using charged particle beams, improving the sensitivity of the resist is a useful technique for improving productivity. Therefore, a highly sensitive chemically amplified resist that generates an acid in an exposed portion or a portion irradiated with a charged particle beam and subsequently promotes a crosslinking reaction or a decomposition reaction by a heat treatment called post-exposure baking (PEB) treatment. Use has become mainstream.
In recent years, with the trend toward miniaturization of semiconductor devices, management of resist shapes on the order of several nanometers has been required.

By the way, in the method using a charged particle beam, especially when the substrate is insulative, the substrate is charged (charged up), and the trajectory of the charged particle beam is bent by the electric field generated by the charged charge, and a desired pattern is obtained. There was a problem that it was difficult to obtain.
Thus, as a means for solving this problem, it is already known that a technique of coating a resist surface with a water-soluble conductive resin is effective.

  On the other hand, as a water-soluble conductive resin, self-doping acidic group-substituted polyaniline capable of developing conductivity without adding a dopant has been proposed. As a synthesis method thereof, a method is proposed in which an acidic group-substituted aniline such as a sulfonic acid group-substituted aniline or a carboxy group-substituted aniline is polymerized with an oxidizing agent in the presence of a basic reaction aid (see Patent Document 1). ). According to Patent Document 1, the reaction product after polymerization is purified by acid treatment or the like to increase the purity of the conductive resin.

JP 2000-219739 A

However, the method described in Patent Document 1 has not sufficiently purified the conductive resin. Oxidizing agents used for polymerization decompose to produce sulfates and ammonia. In particular, acidic substances such as sulfates and basic substances such as ammonia and basic reaction aids can be sufficiently removed. There wasn't.
Therefore, when this conductive resin is applied to a chemically amplified resist, a small amount of acidic substance or basic substance is transferred to the resist side during exposure, PEB treatment and development with the conductive film formed on the resist. There is a problem that the pattern shape changes or the sensitivity fluctuates. Specifically, when the resist is a positive type, if the acidic substance moves to the resist side, the resist in the unexposed area is dissolved during development, so the resist film is reduced, the pattern is thinned, and the sensitivity toward the high sensitivity side is reduced. Variations occur. On the other hand, when the basic substance moves to the resist side, the acid in the exposed portion is deactivated, resulting in a change in pattern shape, a sensitivity fluctuation toward the low sensitivity side, and the like. Further, when the resist is a negative type, the transfer of the acidic substance and the basic substance to the resist causes the opposite phenomenon.

  The present invention has been made in view of the above circumstances, and provides a method for producing a conductive resin composition capable of forming a good pattern shape with little fluctuation in sensitivity, and a conductive resin composition obtained therefrom. Objective.

  As a result of intensive studies, the present inventors have polymerized acidic group-substituted aniline in the presence of a basic reaction aid, and then removed the basic substance and added a basic additive to reduce sensitivity fluctuations. The inventors have found that a conductive resin composition capable of forming a good pattern shape is obtained, and have completed the present invention.

That is, the method for producing a conductive resin composition of the present invention includes a first step of obtaining a conductive resin by polymerizing an acidic group-substituted aniline with an oxidizing agent in the presence of a basic reaction aid, and the obtained conductive property. A second step of removing the basic substance from the reaction mixture containing the functional resin, and a third step of further adding a basic additive to the reaction mixture.
Here, it is preferable that the basic substance is removed by an ion exchange method.
Further, the basic additive is preferably a quaternary ammonium salt.
In addition, the conductive resin composition of the present invention is obtained by the method for producing the conductive resin composition.
Here, the pH at 25 ° C. is preferably 2.5 to 6.0.

According to the method for producing a conductive resin composition of the present invention, a conductive resin composition that can form a good pattern shape with less sensitivity fluctuation is obtained.
Moreover, the conductive resin composition of the present invention has a small sensitivity variation and can form a good pattern shape.

Hereinafter, the present invention will be described in detail.
The manufacturing method of the conductive resin composition of this invention includes the 1st process mentioned later, the 2nd process, and the 3rd process.
Here, in the present invention, “conductive” means having a volume resistivity of 10 ⁹ Ω · cm or less.

<First step>
The first step is a step of obtaining a conductive resin by polymerizing acidic group-substituted aniline with an oxidizing agent in the presence of a basic reaction aid.
Typical examples of the acidic group-substituted aniline are sulfone group-substituted anilines or carboxyl group-substituted anilines. Sulfone group-substituted aniline is preferred, and tends to exhibit higher conductivity than carboxyl group-substituted aniline.

Representative examples of the sulfone group-substituted anilines are aminobenzene sulfonic acids, specifically, alkyl group-substituted aminobenzene sulfonic acids, alkoxy-substituted aminobenzene sulfonic acids, hydroxy group-substituted aminobenzene sulfonic acids, nitro group-substituted amino. Examples include halogen-substituted aminobenzene sulfonic acids such as benzene sulfonic acids, fluoroaminobenzene sulfonic acid, chloroaminobenzene sulfonic acid, and bromoaminobenzene sulfonic acid.
Among these, alkoxy-substituted aminobenzenesulfonic acid is preferable from the viewpoint of improving the polymerization rate.

  Examples of the alkoxy-substituted aminobenzenesulfonic acid include 2-aminoanisole-3-sulfonic acid, 2-aminoanisole-4-sulfonic acid, 2-aminoanisole-6-sulfonic acid, 3-aminoanisole-2-sulfonic acid, Examples include 3-aminoanisole-4-sulfonic acid and 3-aminoanisole-5-sulfonic acid.

  Although it does not specifically limit as a basic reaction auxiliary agent, Ammonia, an aliphatic amine, cyclic saturated amines, cyclic unsaturated amines, etc. are used preferably. Among these, aliphatic amines, cyclic saturated amines, and cyclic unsaturated amines are preferable.

  Examples of the fatty amines include a compound represented by the following general formula (1), a quaternary ammonium salt represented by the following general formula (2), and the like.

In formula (1), R ^{1 to} R ³ are each independently a group selected from the group consisting of an alkyl group having 1 to 3 carbon atoms, —CH ₂ OH and —CH ₂ CH ₂ OH.

In formula (2), R ^{4 to} R ⁷ are each independently a group selected from the group consisting of hydrogen, an alkyl group having 1 to 3 carbon atoms, —CH ₂ OH and —CH ₂ CH ₂ OH.

Examples of the cyclic saturated amines include piperidine, pyrrolidine, morpholine, piperazine and derivatives having these skeletons, and ammonium hydroxide compounds thereof.
Examples of the cyclic unsaturated amines include pyridine, α-picoline, β-picoline, γ-picoline, quinoline, isoquinoline, pyrroline and derivatives having these skeletons, and ammonium hydroxide compounds thereof.

Among the basic reaction aids mentioned above, especially methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylmethylamine, ethyldimethylamine, diethylmethylamine, pyridine, α-picoline, β-picoline, γ-picoline Is preferably used.
If these are used as basic reaction aids, the conductive resin is likely to precipitate as the polymerization proceeds, which is advantageous from the viewpoint of solid recovery and washing.
Each of the basic reaction auxiliaries may be used alone, or two or more basic reaction auxiliaries may be mixed and used in an arbitrary ratio.

  The concentration of the basic reaction aid is preferably 0.1 mol / L or more, more preferably 0.1 to 10.0 mol / L, and particularly preferably 0.2 to 8.0 mol / L. When the concentration of the basic reaction aid is 0.1 mol / L or more, the conductive resin composition can be obtained in high yield. On the other hand, if the concentration of the basic reaction aid is 10.0 mol / L or less, the conductivity of the resulting conductive resin composition tends to be improved.

  The molar ratio of acidic group-substituted aniline and basic reaction assistant is preferably acidic group-substituted aniline: basic reaction assistant = 1: 100 to 100: 1, more preferably 10:90 to 90:10, 50:50 to 90:10 is particularly preferred. Here, when the ratio of the basic reaction aid is low, the reactivity may decrease, or the conductivity of the obtained conductive resin composition may decrease. On the other hand, when the ratio of the basic reaction assistant is high, the ratio of the acidic group of the conductive resin and the basic reaction assistant forming a salt may be high, and the conductivity of the conductive resin composition may be lowered.

The oxidizing agent is not particularly limited as long as the standard electrode potential is 0.6 V or more. For example, peroxodisulfuric acids such as peroxodisulfuric acid, ammonium peroxodisulfate, sodium peroxodisulfate, and potassium peroxodisulfate; It is preferable to use hydrogen peroxide or the like.
These oxidizing agents may be used alone or in a combination of two or more at any ratio.

1-5 mol is preferable with respect to 1 mol of acidic group substituted anilines, and, as for the usage-amount of an oxidizing agent, 1-3 mol is more preferable.
In the present invention, it is important to carry out the polymerization in a system in which the oxidizing agent is present in an equimolar amount or more with respect to the acidic group-substituted aniline. It is also effective to use a transition metal compound such as iron or copper in combination with an oxidizing agent as a catalyst.

  As a polymerization method, for example, a method in which a mixed solution of an acidic group-substituted aniline and a basic reaction assistant is dropped in an oxidizing agent solution, or an oxidizing agent solution is dropped in a mixed solution of an acidic group-substituted aniline and basic reaction assistant. Examples thereof include a reaction method in which a mixed solution of an acidic group-substituted aniline and a basic reaction auxiliary and an oxidizing agent solution are dropped simultaneously in a method, a reaction vessel or the like.

  The polymerization is preferably performed while stirring the inside of the polymerization system. The reaction temperature during polymerization is preferably 50 ° C. or lower, more preferably −15 to 50 ° C., and particularly preferably −10 to 40 ° C. If reaction temperature is 50 degrees C or less, it will become difficult to produce a side reaction and the change of the oxidation-reduction structure of a principal chain, and it can suppress that the electroconductivity of the obtained conductive resin composition falls. In addition, if reaction temperature is -15 degreeC or more, reaction will be completed in a short time.

Examples of the solvent used for the polymerization include water or a mixed solvent of water and an organic solvent. Examples of the organic solvent include methanol, ethanol, 2-propanol, acetone, acetonitrile, dimethylformamide, dimethylacetamide and the like.
In addition, when using a mixed solvent as a solvent used for superposition | polymerization, although the mixing ratio of water and an organic solvent is arbitrary, water: organic solvent = 1: 100-100: 1 is preferable.

  Unreacted monomer (acid group-substituted aniline) is dissolved in the reaction solution after polymerization. Therefore, it is preferable to perform an operation of separating the reaction mixture containing the conductive resin from the reaction solution. As the separation device used at this time, vacuum filtration, pressure filtration, centrifugal separation, centrifugal filtration or the like is used. In particular, it is preferable to use a separation device such as centrifugal separation or centrifugal filtration because it is easy to obtain a high-purity one.

  After separating the reaction mixture containing the conductive resin from the reaction solution, the reaction mixture may be purified. Purification can be carried out using a washing solvent, which includes alcohols such as methanol, ethanol, 2-propanol, 1-propanol and t-butanol, acetone, acetonitrile, N, N-dimethylformamide, N-methyl. Pyrrolidone, dimethyl sulfoxide, and the like are preferable because high purity products can be obtained. In particular, methanol, ethanol, 2-propanol, acetone, and acetonitrile are effective.

<Second step>
The second step is a step of removing the basic substance from the reaction mixture containing the conductive resin obtained in the first step.
The basic substance removed in the second step is mainly a residue of the basic reaction aid used in the first step or a decomposition product of the oxidizing agent.

  As described above, when the conductive material is formed on the resist and the basic substance that is a decomposition product of the basic reaction aid or the oxidizing agent moves to the resist side, if the resist is a positive type, The acid was deactivated, and the pattern shape was likely to change and the sensitivity fluctuation to the low sensitivity side was likely to occur. On the contrary, when the resist is a negative type, the pattern is thinned, the film is reduced, and the sensitivity fluctuation toward the high sensitivity side is likely to occur.

  However, according to the present invention, when the conductive material is formed on the resist using the conductive resin composition of the present invention by removing the basic substance from the reaction mixture in the second step, the conductive material is heated by heating. It is possible to suppress the volatilization of the basic substance from the membrane. Therefore, in particular, in a pattern formation method using a charged particle beam using a chemically amplified resist, transfer of a basic substance to the resist side is suppressed, and a change in pattern shape and a sensitivity variation can be suppressed.

The transfer of the basic substance to the resist side can be confirmed by a volatile component analysis of the conductive resin composition using an EGA-MS (Evolved Gas Analysis-Mass Spectrometry) method.
Normally, considering that the PEB treatment temperature of the resist is around 120 ° C., when the volatilization start temperature of the basic substance from the conductive resin composition is less than 120 ° C., the transition to the resist side is severe, When volatilization starts in the range of from ℃ .degree. C. to less than 130.degree. Accordingly, the volatilization start temperature is preferably 130 ° C. or higher, and particularly preferably 140 ° C. or higher.

  The method for removing the basic substance is not particularly limited, column-type treatment using an ion exchange resin, batch-type treatment, treatment using an ion-exchange membrane, electrodialysis, and further acid washing in a protonic acid solution, Although any method such as removal by heat treatment or neutralization precipitation can be used, the ion exchange method is particularly effective. By using the ion exchange method, it is possible to effectively remove the basic substance present in the state of forming a salt with an acidic group of the conductive resin, and to obtain a highly pure conductive resin composition.

Examples of the ion exchange method include an ion exchange method using a cation exchange resin and an electrodialysis method.
When the basic substance is removed by the ion exchange method, the basic substance is removed after dissolving the reaction mixture in an aqueous medium so as to have a desired solid content concentration to obtain a reaction mixture solution.
Examples of the aqueous medium include water, a water-soluble organic solvent, and a mixed solvent of water and a water-soluble organic solvent.
The water-soluble organic solvent is an organic solvent soluble in water, for example, alcohols such as methanol, ethanol, 2-propanol, 1-propanol, and 1-butanol; acetone, methyl ethyl ketone, ethyl isobutyl ketone, methyl isobutyl ketone, and the like. Ketones; ethylene glycols such as ethylene glycol, ethylene glycol methyl ether, ethylene glycol mono-n-propyl ether; propylene glycols such as propylene glycol, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, propylene glycol propyl ether Amides such as dimethylformamide and dimethylacetamide; pyrrolidones such as N-methylpyrrolidone and N-ethylpyrrolidone; Methyl acid, ethyl lactate, beta-methoxyisobutyrate methyl butyrate, hydroxypropyl esters such as α- hydroxy methyl isobutyrate and the like.

In the case of an ion exchange method using a cation exchange resin, the amount of the sample liquid with respect to the cation exchange resin is, for example, up to 10 times the volume of the cation exchange resin in the case of a reaction mixture solution having a solid content concentration of 5% by mass. Is preferred, and up to 5 times the volume is more preferred.
Examples of the cation exchange resin include “Amberlite IR-120H” manufactured by Organo Corporation.

In the case of the electrodialysis method, the ion exchange membrane of the electrodialysis method is not particularly limited, but is an ion exchange membrane that has been subjected to a monovalent ion selective permeation treatment in order to further suppress permeation due to diffusion of impurities. It is preferable to use a molecular weight of 300 or less. As such an ion exchange membrane, for example, “Neocepta CMK (cation exchange membrane, fractional molecular weight 300)”, “Neoceptor AMX (anion exchange membrane, fractional molecular weight 300)” manufactured by Astom Co., Ltd. and the like are suitable.
In addition, as an ion exchange membrane used in the electrodialysis method, a bipolar membrane which is an ion exchange membrane having a structure in which an anion exchange layer and a cation exchange layer are bonded together may be used. As such a bipolar film, for example, “PB-1E / CMB” manufactured by Astom Co., Ltd. is suitable.
The current density in electrodialysis is preferably less than the limit current density. The applied voltage in the bipolar film is preferably 10 to 50V, and more preferably 25 to 35V.

When the basic substance is removed by a method other than the ion exchange method described above, for example, by acid washing in a proton acid solution, the basic substance can be removed by stirring the reaction mixture in the proton acid solution. . After stirring, the proton acid solution may be removed by filtration.
Examples of the proton acid solution include mineral acids such as hydrochloric acid, nitric acid, sulfuric acid and borofluoric acid, super strong acids such as trifluoromethanesulfonic acid, methanesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfonic acid, camphorsulfonic acid. Organic sulfonic acids such as polystyrene sulfonic acid, polyacrylic acid, polyvinyl sulfonic acid, poly-2-methylpropane-2-acrylamide sulfonic acid and the like. Among these, hydrochloric acid, nitric acid, sulfuric acid, and p-toluenesulfonic acid are preferable.

<Third step>
The third step is a step of further adding a basic additive to the reaction mixture after the second step.
As described above, when an acidic substance such as a decomposition product of an oxidant moves to the resist side when a conductive film is formed on the resist, if the resist is a positive type, the pattern is thinned, the film is reduced, and the high sensitivity side. Sensitivity fluctuations were likely to occur. On the other hand, when the resist is a negative type, a change in the pattern shape and a sensitivity fluctuation toward the low sensitivity side tend to occur.

  However, if it is this invention, an acidic substance will form a salt with a basic additive easily by adding a basic additive to a reaction mixture in a 3rd process. As a result, when the conductive film is formed on the resist using the conductive resin composition of the present invention, it is possible to suppress volatilization of the acidic substance from the conductive film by heating. Therefore, in particular, in a pattern formation method using a charged particle beam using a chemically amplified resist, the migration of an acidic substance to the resist side is suppressed, and a change in pattern shape and sensitivity fluctuation can be suppressed. In addition, by removing basic substances in the second step and adding basic additives in the third step, the amount of basic substances present in the system can be controlled, and fluctuations in sensitivity are suppressed. can do.

The transfer of the acidic substance to the resist side can be confirmed by volatile component analysis of the conductive resin composition using the EGA-MS method.
Normally, considering that the PEB treatment temperature of the resist is around 120 ° C., when the volatilization start temperature of the acidic substance from the conductive resin composition is less than 120 ° C., the transition to the resist side is severe, When volatilization starts in the range of 130 ° C. or lower, there is a possibility of shifting to the resist side depending on the PEB processing temperature. Accordingly, the volatilization start temperature is preferably 130 ° C. or higher, and particularly preferably 140 ° C. or higher.

Although it does not specifically limit as a basic additive used at a 3rd process, For example, what was illustrated in description of the basic reaction adjuvant used at a 1st process is mentioned. Among them, a strong base is preferable from the viewpoint that the volatilization temperature of the salt formed with the acidic substance becomes high and volatilization of the acidic substance can be suppressed. A quaternary ammonium salt is preferable, specifically, ammonium hydroxide such as tetramethylammonium hydride, tetramethylol ammonium hydride, tetraethylammonium hydride, tetra n-butylammonium hydride, tetrasec-butylammonium hydride, tetra-t-butylammonium hydride, etc. Compounds.
The basic additive may be the same as or different from the basic reaction aid. Moreover, you may use individually by 1 type and may mix and use 2 or more types by arbitrary ratios.

When adding the basic additive, if the basic substance is removed by the ion exchange method in the second step, the subsequent reaction mixture solution can be used as it is.
When the reaction mixture after the second step is solid, it is preferable to dissolve the reaction mixture in the above-described aqueous medium so as to have a desired solid content concentration and use it as a reaction mixture solution.

The method for adding the basic additive is not particularly limited, and can be added to the reaction mixture at an arbitrary temperature and addition rate. Usually, the basic additive is added while stirring the reaction mixture solution at room temperature. It is preferable to add.
In the present invention, “room temperature” means 25 ° C.

  Although the amount of the basic additive added will be described later in detail, it may be adjusted so that the pH of the obtained conductive resin composition becomes a desired value. 1-50 mass parts is preferable, 0.3-10 mass parts is more preferable, 0.3-0.9 mass part is especially preferable. If the addition amount of the basic additive is 0.1 parts by mass or more, it is sufficient that an acidic substance is generated from the conductive film by heating when the conductive film is formed on the resist using the conductive resin composition. Can be suppressed. On the other hand, if the addition amount of the basic additive is 50 parts by mass or less, generation of a basic substance from the conductive film by heating can be sufficiently suppressed.

The reaction mixture after the third step is in a state dissolved in an aqueous medium (reaction mixture solution), but this reaction mixture solution can be used as it is as a conductive resin composition.
Further, the reaction mixture obtained by removing the aqueous medium from the reaction mixture solution with an evaporator or the like may be used as the conductive resin composition, and further, the reaction mixture is dissolved in the above-mentioned aqueous medium to form the conductive resin composition. Also good. Since the reaction mixture is soluble, it is readily soluble in aqueous media. However, among the water-soluble organic solvents exemplified above in the description of the aqueous medium, there are those in which the reaction mixture is difficult to dissolve when used alone (for example, methanol). In such a case, the reaction mixture may be dissolved in a mixed solvent with water.

  The conductive resin composition thus obtained preferably has a pH of 2.5 to 6.0 at 25 ° C. If pH is 2.5 or more, when a conductive film is formed on a resist using a conductive resin composition, generation of an acidic substance from the conductive film by heating can be sufficiently suppressed. On the other hand, if pH is 6.0 or less, it can fully suppress that a basic substance generate | occur | produces from a electrically conductive film by heating.

The pH of the conductive resin composition can be adjusted by the amount of basic additive added to the reaction mixture in the third step. Specifically, when the amount of the basic additive added increases, the pH of the conductive resin composition tends to increase.
The pH of the conductive resin composition is a value obtained by measuring a conductive resin composition containing an aqueous medium as a solvent and having a solid content concentration of 2% by mass with a pH meter at a liquid temperature of 25 ° C.

The conductive resin composition of the present invention is applied to the surface of a substrate by a method used for general paints.
Examples of the coating method for the conductive resin composition include a gravure coater, roll coater, curtain flow coater, spin coater, bar coater, reverse coater, kiss coater, phantom coater, rod coater, air doctor coater, knife coater, blade coater. Application methods such as cast coater and screen coater, spraying methods such as spray coating, dipping methods such as dip, etc., are usually applied onto a resist coated on a silicon wafer, quartz mask substrate, etc. using a spin coater. Apply.
In addition, you may add alcohol, surfactant, etc. to a conductive resin composition in order to improve applicability | paintability.

  As described above, according to the present invention, it is possible to obtain a conductive resin composition that generates less acidic substances and basic substances by heating. In the conductive resin composition, particularly in a pattern formation method using a charged particle beam using a chemically amplified resist, transfer of an acidic substance and a basic substance to the resist is suppressed. Pattern shapes can be formed.

Applications of the conductive resin composition obtained by the present invention include an antistatic film, a capacitor, a transparent electrode, and a semiconductor material used on the resist surface of a pattern forming method using a charged particle beam using a chemically amplified resist. .
Among these, when used as an antistatic film used on a resist surface in a pattern formation method by a charged particle beam using a chemically amplified resist, the conductive resin composition of the present invention is applied to the resist surface by various coating methods. After that, pattern formation with a charged particle beam is performed, whereby a pattern shape with high resolution can be obtained.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.
The various measurement / evaluation methods in Examples and Comparative Examples are as follows.

<Measurement and evaluation method>
(Measurement of pH)
Using a pH meter (model F-55S) manufactured by HORIBA, Ltd. and a glass electrode for ultraprecision (model 6367-10D), the pH of the conductive resin composition was measured at a liquid temperature of 25 ° C.

<Analysis of volatile components>
(Evaluation of basic substances)
The basic substance was analyzed using the EGA-MS method.
Specifically, 1 mg of a sample was collected from a solid material obtained by drying the conductive resin composition at 40 ° C. for 2 hours with a vacuum dryer, and placed in a sample cup. Subsequently, it was introduced into a thermal decomposition apparatus (frontier lab, “PY-2010D”) in a helium atmosphere at a flow rate of 50 mL / min, and the temperature was increased from 50 ° C. to 200 ° C. at a temperature increase rate of 5 ° C./min. . The pyrolysis gas generated at this time was collected in an amount of 1/50 of the total amount. Then, the pyrolysis gas collected into a column of a 300 ° C. gas chromatograph (manufactured by Agilent, “6890 type GC”) using 1 mL / min of helium as a carrier gas is fed into a mass spectrometer (manufactured by Agilent, “ 5997N ")).
As the column, a column having a length of 2.5 m and a diameter of 0.15 mm (Ultra Alloy DTM) without a liquid phase was used. Mass spectrometry set the mass range (m / Z) = 17 to 500 as the detection range. Characteristic ions (pyridine: m / Z = 79, triethylamine: m / Z = 86, tetramethylammonium hydride (TMAH) -derived components: m / Z = 85, tetraethylammonium hydride (TEAH) in the mass spectrum of each basic substance ) Origin component: m / Z = 86) The generation (volatilization) start temperature was confirmed, and the occurrence of basic substances was evaluated according to the following evaluation criteria.
A: At 140 ° C., no volatilization of any ions is confirmed.
○: Volatilization of any ions was confirmed between 130 ° C. and 140 ° C.
(Triangle | delta): Volatilization of either ion was confirmed between 120 degreeC or more and less than 130 degreeC.
X: Volatilization of any ion was confirmed at less than 120 ° C.

(Evaluation of acidic substances)
In the same manner as the evaluation of basic substances, acidic substances were analyzed with a mass spectrometer using the EGA-MS method.
Mass spectrometry set the mass range (m / Z) = 17 to 500 as the detection range. Generation (volatilization) start temperature of characteristic ions (sulfonic acid-derived component: m / Z = 64) was confirmed in the mass spectrum of the acidic substance, and the generation of the acidic substance was evaluated according to the following evaluation criteria.
A: Volatilization is not confirmed at 140 ° C.
○: Volatilization was confirmed between 130 ° C. and less than 140 ° C.
(Triangle | delta): Volatilization was confirmed between 120 degreeC or more and less than 130 degreeC.
X: Volatilization was confirmed at less than 120 ° C.

[Example 1]
<First step>
1 mol of 2-aminoanisole-4-sulfonic acid was dissolved in 300 mL of pyridine in water / acetonitrile = 3: 7 at a concentration of 4 mol / L (0.36 mol of pyridine) at 0 ° C. to obtain a monomer solution.
Separately, 1 mol of ammonium peroxodisulfate was dissolved in 1 L of a solution of water / acetonitrile = 3: 7 to obtain an oxidant solution.
Subsequently, the monomer solution was dropped while the oxidant solution was cooled to 5 ° C. After completion of dropping, the mixture was further stirred at 25 ° C. for 12 hours to obtain a conductive resin. Thereafter, the obtained reaction mixture containing the conductive resin was separated by a centrifugal filter. Furthermore, it was made to dry after wash | cleaning with methanol, and 185g of powdery reaction mixture (a-0) was obtained.
20 g of the obtained reaction mixture (a-0) was dissolved in a mixed solvent of 940 g of pure water and 40 g of 2-propanol to obtain 1000 g of a reaction mixture solution (a-1) having a solid content concentration of 2% by mass.

<Second step>
500 mL of a cation exchange resin (manufactured by Organo Corporation, “Amberlite IR-120H”) washed with ultrapure water was packed in a column. 800 g of the reaction mixture solution (a-1) was passed through this column at a rate of 50 mL / min (SV = 6) to obtain 700 g of the reaction mixture solution (a-2) from which the basic substance was removed.
One swedl lap (SV) is defined as 1 × 10 ⁶ m ³ / s (1GL / s).

<Third step>
While maintaining 100 g of the reaction mixture solution (a-2) at room temperature, 3.6 g of a 10% by mass aqueous solution of TMAH was added with stirring to obtain a conductive resin composition (A-1).

Table 1 shows types of the reaction mixture, reaction mixture solution, and conductive resin composition obtained in each step.
Moreover, various measurement and evaluation were performed about the obtained conductive resin composition (A-1). The results are shown in Table 2.

[Example 2]
In the third step, a conductive resin composition (A-2) was prepared in the same manner as in Example 1 except that the amount of the 10% by mass aqueous solution of TMAH was changed to 5.4 g, and various measurements and evaluations were made. Went. Table 1 shows types of the reaction mixture, reaction mixture solution, and conductive resin composition obtained in each step. Various measurements and evaluation results are shown in Table 2.

[Example 3]
In the third step, a conductive resin composition (A-3) was prepared in the same manner as in Example 1, except that 5.8 g of a 10% by weight aqueous solution of TEAH was added instead of the 10% by weight aqueous solution of TMAH. Various measurements and evaluations were performed. Table 1 shows types of the reaction mixture, reaction mixture solution, and conductive resin composition obtained in each step. Various measurements and evaluation results are shown in Table 2.

[Example 4]
In the third step, a conductive resin composition (A-4) was prepared in the same manner as in Example 1 except that 8.7 g of a 10% by mass aqueous solution of TEAH was added instead of the 10% by mass aqueous solution of TMAH. Various measurements and evaluations were performed. Table 1 shows types of the reaction mixture, reaction mixture solution, and conductive resin composition obtained in each step. Various measurements and evaluation results are shown in Table 2.

[Example 5]
In the third step, a conductive resin composition (A-5) was prepared in the same manner as in Example 1 except that 9.0 g of a 10% by mass aqueous solution of TEAH was added instead of the 10% by mass aqueous solution of TMAH. Various measurements and evaluations were performed. Table 1 shows types of the reaction mixture, reaction mixture solution, and conductive resin composition obtained in each step. Various measurements and evaluation results are shown in Table 2.

[Example 6]
In the third step, a conductive resin composition (A-6) was prepared in the same manner as in Example 1 except that 9.7 g of a 10% by mass aqueous solution of TEAH was added instead of the 10% by mass aqueous solution of TMAH. Various measurements and evaluations were performed. Table 1 shows types of the reaction mixture, reaction mixture solution, and conductive resin composition obtained in each step. Various measurements and evaluation results are shown in Table 2.

[Example 7]
<First step>
A powdery reaction mixture (b-0) was prepared in the same manner as in the first step of Example 1, except that 4 mol / L concentration of triethylamine was used as a basic reaction aid instead of 4 mol / L concentration of pyridine. ) Was obtained.
20 g of the obtained reaction mixture (b-0) was dissolved in a mixed solvent of 940 g of pure water and 40 g of 2-propanol to obtain 1000 g of a reaction mixture solution (b-1) having a solid content concentration of 2% by mass.

<Second step>
Instead of the reaction mixture solution (a-1), except that 800 g of the reaction mixture solution (b-1) was used, the reaction mixture solution (in which the basic substance was removed in the same manner as in the second step of Example 1) ( 700 g of b-2) was obtained.

<Third step>
Instead of the reaction mixture solution (a-2), 100 g of the reaction mixture solution (b-2) was used, and the addition amount of the 10% by mass aqueous solution of TMAH was changed to 5.4 g. A conductive resin composition (B-1) was prepared in the same manner as in the steps, and various measurements and evaluations were performed. Table 1 shows types of the reaction mixture, reaction mixture solution, and conductive resin composition obtained in each step. Various measurements and evaluation results are shown in Table 2.

[Example 8]
In the same manner as in the first step of Example 7, 185 g of a reaction mixture (b-0) was obtained.
Subsequently, in the second step, 15 g of the reaction mixture (b-0) was stirred in an acetone solution of 1 mol / L p-toluenesulfonic acid for 1 hour and then filtered off. Furthermore, it was made to dry after wash | cleaning with methanol, and 14g of powdery reaction mixtures (b-2-1) from which the basic substance was removed were obtained.
2 g of the obtained reaction mixture (b-2-1) was dissolved in 98 g of pure water at room temperature to obtain 100 g of a reaction mixture solution (b-2-2) having a solid content concentration of 2% by mass.
Next, in the third step, 100 g of the reaction mixture solution (b-2-2) was used instead of the reaction mixture solution (a-2), and the addition amount of the 10% by mass aqueous solution of TMAH was changed to 5.4 g. Except for the above, a conductive resin composition (B-2) was prepared in the same manner as in the third step of Example 1, and various measurements and evaluations were performed. Table 1 shows types of the reaction mixture, reaction mixture solution, and conductive resin composition obtained in each step. Various measurements and evaluation results are shown in Table 2.

[Comparative Example 1]
Various measurements and evaluations were performed using the reaction mixture solution (a-1) obtained in Example 1 as a conductive resin composition. Table 1 shows types of the reaction mixture, reaction mixture solution, and conductive resin composition obtained in each step. Various measurements and evaluation results are shown in Table 2.

[Comparative Example 2]
Various measurements and evaluations were performed using the reaction mixture solution (b-1) obtained in Example 7 as a conductive resin composition. Table 1 shows types of the reaction mixture, reaction mixture solution, and conductive resin composition obtained in each step. Various measurements and evaluation results are shown in Table 2.

[Comparative Example 3]
Various measurements and evaluations were performed using the reaction mixture solution (a-2) obtained in Example 1 as a conductive resin composition. Table 1 shows types of the reaction mixture, reaction mixture solution, and conductive resin composition obtained in each step. Various measurements and evaluation results are shown in Table 2.

[Comparative Example 4]
Various measurements and evaluations were performed using the reaction mixture solution (b-2) obtained in Example 7 as a conductive resin composition. Table 1 shows types of the reaction mixture, reaction mixture solution, and conductive resin composition obtained in each step. Various measurements and evaluation results are shown in Table 2.

[Comparative Example 5]
Various measurements and evaluations were performed using the reaction mixture solution (b-2-2) obtained in Example 8 as a conductive resin composition. Table 1 shows types of the reaction mixture, reaction mixture solution, and conductive resin composition obtained in each step. Various measurements and evaluation results are shown in Table 2.

[Comparative Example 6]
In the same manner as in the first step of Example 7, 1000 g of a reaction mixture solution (b-1) was obtained.
Next, the second step is not carried out. In the third step, 100 g of the reaction mixture solution (b-1) is used instead of the reaction mixture solution (a-2), and the addition amount of a 10% by mass aqueous solution of TMAH. The conductive resin composition (B-3) was prepared in the same manner as in the third step of Example 1 except that the value was changed to 5.4 g, and various measurements and evaluations were performed. Table 1 shows types of the reaction mixture, reaction mixture solution, and conductive resin composition obtained in each step. Various measurements and evaluation results are shown in Table 2.

As is clear from Table 2, the conductive resin composition of each Example obtained through the first step, the second step, and the third step was a base at around 120 ° C. when heated. Volatilization of acidic substances and acidic substances was suppressed. In particular, in Examples 1 to 7 using the ion exchange method as the method for removing the basic substance in the second step, the basic substance was not volatilized at a temperature lower than 130 ° C.
Therefore, the conductive resin composition obtained in each example is applied to the resist side of a very small amount of acidic substance or basic substance during PEB treatment, particularly in the case of a pattern formation method using a charged particle beam using a chemically amplified resist. From this, it was shown that a good pattern shape can be formed with little sensitivity fluctuation. From the results of each Example, it can be said that a conductive resin composition having a pH of 2.5 to 6.0 is particularly suitable.
In addition, the conductive resin composition can be applied to various other electronic device applications.

On the other hand, in the conductive resin compositions of Comparative Examples 1 and 2 obtained without performing the second step and the third step, the basic substance and the acidic substance were volatilized at a temperature lower than 120 ° C. when heated.
In the conductive resin compositions of Comparative Examples 3 to 5 obtained without performing the third step, the basic material was removed in the second step. Therefore, the basic material volatilized at around 120 ° C. when heated. Was suppressed, but the acidic substance volatilized below 120 ° C.
In the conductive resin composition of Comparative Example 6 obtained without performing the second step, the basic additive was added in the third step, so that the volatilization of the acidic substance at 140 ° C. was suppressed when heated. Although it was made, the basic substance volatilized below 120 ° C.
Therefore, the conductive resin compositions obtained in the respective comparative examples are such that, in the case of a pattern formation method using a charged particle beam using a chemically amplified resist, a small amount of acidic substance or basic substance is transferred to the resist side during PEB treatment. It was shown that it was easy to shift, the sensitivity was likely to change, and the pattern shape was likely to change.

Claims (5)

  A first step of polymerizing acidic group-substituted aniline with an oxidizing agent in the presence of a basic reaction aid to obtain a conductive resin, and a second step of removing the basic substance from the reaction mixture containing the obtained conductive resin. And a third step of adding a basic additive to the reaction mixture, and a method for producing a conductive resin composition.   The method for producing a conductive resin composition according to claim 1, wherein the basic substance is removed by an ion exchange method.   The method for producing a conductive resin composition according to claim 1, wherein the basic additive is a quaternary ammonium salt.   The conductive resin composition obtained from the manufacturing method of the conductive resin composition as described in any one of Claims 1-3.   The conductive resin composition according to claim 4, which has a pH at 2.5 ° C. of 2.5 to 6.0.