Conductive polymer composition, coated article, and pattern forming method

Abstract

To provide a conductive polymer composition excellent in filterability and deposition property of a flat film on an electron beam resist, showing excellent antistatic property also in electron beam lithography, and minimizing an influence of an acid that diffuses by the film, and capable of suitably using in an electron beam resist lithography antistatic film excellent also in peelability.SOLUTION: (A) A conductive polymer composition comprises a polyaniline-based conductive polymer having a repeating unit represented by the following general formula (1) and a specific polymer having a pyrrolidinium salt structure moiety. (In the formula, R1 to R4 represent a hydrogen atom, an acidic group, a hydroxy group, an alkoxy group, a carboxyl group, a nitro group, a halogen atom, or a hydrocarbon group.)SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a conductive polymer composition containing a polyaniline-based conductive polymer, a coated article using the same, and a pattern forming method. [Background technology]

[0002] In the manufacturing process of semiconductor devices such as ICs and LSIs, microfabrication has traditionally been performed using lithography with photoresist. This method involves inducing crosslinking or decomposition reactions in a thin film by irradiating it with light, significantly changing the solubility of the thin film, and then using the resist pattern obtained as a result of a development process using a solvent or other material as a mask to etch the substrate. In recent years, with the increasing integration of semiconductor devices, there has been a demand for high-precision microfabrication using short-wavelength light. Electron-beam lithography, with its short wavelength characteristics, is being developed as a next-generation technology.

[0003] A problem specific to electron beam lithography is the charging phenomenon (charge-up) that occurs during exposure. This occurs when an insulating resist film is coated on the substrate used for electron beam exposure, causing charges to accumulate on or within the resist film. This charging bends the trajectory of the incident electron beam, significantly reducing the accuracy of imaging. For this reason, peelable antistatic films that can be applied to the electron beam resist are being investigated.

[0004] As electron beam lithography mentioned above continues to scale down to the <5 nm generation, the positional accuracy of electron beam writing on electron beam resists is becoming increasingly important. With regard to writing technology, advances are being made in conventional techniques, such as increasing the current and MBMW (multi-beam mask writing), and it is expected that the charging state on the resist will become even greater. Therefore, conductive polymers with lower resistivity and higher charge dissipation capacity are desired as a means of improving the antistatic properties of antistatic films to accommodate future developments in writing technology.

[0005] Patent Document 1 discloses that in order to reduce the decrease in drawing accuracy due to charging on the resist, a π-conjugated conductive polymer with an acidic substituent introduced into its structure is coated on the resist, and the formed conductive polymer film exhibits an antistatic effect during electron beam writing, thereby eliminating various problems due to charging phenomena, such as the electrostatic adverse effects on lithography positional accuracy during electron beam irradiation and distortion of the resist pattern. It also clearly states that the conductive polymer film remains water-soluble even after electron beam writing at a high dose, and can therefore be removed by rinsing with water.

[0006] Patent Document 2 discloses a composition comprising a polyaniline-based conductive polymer, a polyacid, and HO, and clearly discloses that a composite comprising a polyaniline-based conductive polymer and a polyacid can be used at a concentration of 5 to 10 mass % to form a satisfactory spin-coating film, and that an antistatic effect is observed at a film thickness of 150 nm, forming an antistatic film that can be peeled off and cleaned with HO.

[0007] Patent Document 3 discloses a technology for using polythiophene-based conductive polymers as antistatic films for electron beam lithography, and demonstrates the antistatic film function of a complex of polythiophene-based conductive polymers and polyanions due to the effect of adding a gemini surfactant, etc.

[0008] Patent Document 4 proposes a new compound in which at least one H atom in the benzene ring skeleton of aniline, the repeating unit of polyaniline-based conductive polymers, is replaced with an acidic group, resulting in self-doping within the polyaniline molecule. In Patent Documents 2 and 3, the polyaniline-based conductive polymer is a composite of aniline oligomer, a π-conjugated polymer responsible for carrier transport, and a sulfonic acid-terminated monomer or polymer, commonly referred to as a dopant. Because the polyaniline exhibits particulate behavior and disperses in HO, homogenization of the material requires processing with a high-power homogenizer or high-pressure disperser. Furthermore, the removal of particle aggregates, which can cause pattern defects after application to electron beam resist, is complicated. In contrast, the compound described in Patent Document 4 solvates in HO and exhibits molecular behavior, dramatically reducing the aforementioned defect factors with simple filtration.

[0009] In paragraphs

[0045] to

[0048] , Patent Document 5 proposes adding a basic compound to a composition containing a compound that self-dopes within a polyaniline molecule to neutralize the acid present in the film when the film is formed on an electron beam resist, preventing the acid from adversely affecting the resist pattern due to interlayer diffusion. Examples of basic compounds listed include ammonium salts of hydroxides such as tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, tetrahexylammonium hydroxide, and benzyltrimethylammonium hydroxide, as well as 1,5-diazabicyclo[4.3.0]-5-nonene (DBN), 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), and their derivatives. However, while hydroxides have strong basicity and neutralize the acid derived from polyaniline, they also have strong nucleophilicity, which can cause side reactions. For example, acid generators contained in EB resists often contain ester bonds as linkers. These ester bonds are subject to nucleophilic attack by hydroxide ions, resulting in the elimination of functional groups that provide diffusion control and solubility. Consequently, the resulting small-molecule sulfonate ions diffuse more readily after electron beam irradiation, resulting in sensitivity fluctuations and pattern defects during lithography. On the other hand, 1,5-diazabicyclo[4.3.0]-5-nonene (DBN) and 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) are strong bases but have weak nucleophilicity, making them less susceptible to nucleophilic attack on the ester bonds. However, due to their small molecular weight, when a conductive composition is deposited on top of an EB resist, they diffuse from the interface into the resist layer, quenching the acid generated from the acid generator after electron beam writing, resulting in sensitivity fluctuations and pattern defects during lithography. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Patent Publication No. 2902727 [Patent Document 2] U.S. Patent No. 5,370,825 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-009342 [Patent Document 4] Patent Publication No. 3631910 [Patent Document 5] Japanese Patent Application Publication No. 2017-39927 [Patent Document 6] Japanese Patent Publication No. 2020-147630 [Patent Document 7] Patent Publication No. 2021-21020 Summary of the Invention [Problem to be solved by the invention]

[0011] The polyaniline compounds disclosed in Patent Documents 1, 4, and 5 use acidic substituents introduced into the π-conjugated conductive polymer monomer unit structure, which self-dops into the π-conjugated conductive polymer chain. However, not all of the acidic substituents present in the π-conjugated conductive polymer after polymerization dope into the π-conjugated system; rather, they exist within the polymer as acids or their salts. When the polyaniline is formed as an antistatic film on an electron beam resist during electron beam irradiation, the acid diffuses into the resist layer, adversely affecting lithography. Furthermore, adding a strong base such as hydroxide as a neutralizing agent to suppress the acid diffusion not only makes neutralization difficult, but also causes unreacted strong bases in the film to penetrate the resist layer and undergo side reactions with nucleophilic attack sites, such as ester bonds, in the resist composition, ultimately adversely affecting sensitivity and lithography. The term "salt state" refers to a state in which the acidic groups contained in the monomer units are neutralized with a strong base such as an amine before polymerization, the resulting monomer is polymerized, and the product is not treated with a cation exchange resin or the like. It is believed that some of the sulfonate salts on the polymer are converted to an acidic state by sulfuric acid, a by-product of the peroxodisulfate used in the polymerization reagent. Even after removal of monomolecular impurities by purification such as ultrafiltration, the acid derived from the polyaniline chains diffuses from the formed film. Therefore, to use this conductive polymer as an antistatic film for electron beam resists, the diffusion of the acid generated from the acid terminals in the polyaniline must be controlled by an additive other than a strong base.

[0012] The effects of strong bases on resists are evident in a post-coating delay (PCD) test, which examines the storage stability of resists coated with an antistatic film but not irradiated with electron beams. During storage without irradiation, the strong bases present in the antistatic film gradually penetrate and diffuse into the resist film, attacking the resist polymer and acid generator with nucleophilic activity, severing the resist linker bonds and cleaving the acid terminals of the electron beam acid generator. During subsequent electron beam lithography, the resist reaction outside the lithography region has progressed, and small-molecule acids are generated that diffuse faster than the original acid generator and react with the resist polymer, resulting in significant sensitivity changes, film loss, and pattern degradation.

[0013] While polyaniline composites using unsubstituted aniline as a raw material generally exhibit high conductivity, they have poor hydrophilicity and dispersibility in HO, resulting in extremely poor film-forming properties on substrates. In contrast, the composition described in Patent Document 2, a composite consisting of a polyaniline-based conductive polymer and polyacid as the base polymer, incorporates various substituents into the aniline skeleton to improve the polyaniline composite's dispersibility in HO and film-forming properties on substrates. Even in the aforementioned electron beam lithography antistatic film application, the composite exhibits rapid response during the stripping and cleaning process with HO. However, introducing substituents other than hydrogen atoms into the aniline skeleton makes it difficult to impart high conductivity. This makes it difficult to improve resistivity, a physical property indicator of antistatic performance, and prevents sufficient dissipation of the charge in future lithography processes that are expected to generate the aforementioned strong electrostatic charge in the resist layer.

[0014] In addition to the aforementioned polyaniline-based conductive polymers, polythiophene-based conductive polymers are also used as π-conjugated conductive polymers for antistatic film applications in the electron beam lithography drawing process. Polythiophene-based conductive polymers generally exhibit higher conductivity than polyaniline-based conductive polymers, but their affinity for HO is lower than that of polyaniline-based conductive polymers. Even if they are HO-dispersible materials, once formed into a film, they are difficult to remove during the HO stripping and cleaning process. Even if they are stripped, they do not completely dissolve or redisperse in HO but instead flow in a solid state such as flakes, which can cause serious pattern defects in lithography.

[0015] Patent Document 3 discloses a technology for using polythiophene-based conductive polymers as antistatic films for electron beam lithography, demonstrating the antistatic film function and good removability against HO of a composite of a polythiophene-based conductive polymer and a polyanion due to the effects of adding a gemini surfactant, etc. Furthermore, the composition described in Patent Document 3 uses a composite of a polythiophene-based conductive polymer and a polyacid as the base polymer, and therefore, like the composite of a polyaniline-based conductive polymer and a polyacid described in Patent Document 2, there is a possibility that the acid derived from the polyacid may affect the resist film, whereas the acidity is alleviated by using a neutralizing agent such as an amine, thereby minimizing the aforementioned effect on lithography. However, when gemini surfactants were added to impart good coating and stripping properties, and amines were added to reduce acidity, side reactions with the resist film by the amines occurred, affecting lithography, and the surface resistivity (Ω / □), an indicator of antistatic performance, showed a high value that did not produce sufficient antistatic performance. In conclusion, the inherent low resistivity of polythiophene-based conductive polymers is not being expressed as a function. Therefore, there is concern that in future imaging processes that require high antistatic performance, the charge will not be able to be sufficiently dissipated.

[0016] In view of the above, there has been a demand for the development of an antistatic film for electron beam resist writing that has good filterability, good film-forming properties for forming a flat film on an electron beam resist, and exhibits excellent antistatic properties even in the electron beam writing process due to its low resistivity, and that controls the acid diffusion rate by salt exchange of the acid through the addition of a carboxylic acid salt as an additive in order to minimize the effects of acid diffusing from the film, without using neutralization with strong bases that have an adverse effect on lithography, and that further has good removability with HO or an alkaline developer after writing.

[0017] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a conductive polymer composition that can be suitably used for antistatic films for electron beam resist writing, which have good filterability and good film-forming properties for forming flat films on electron beam resists, exhibit excellent antistatic properties even in electron beam writing processes due to their low volume resistivity (Ω·cm), minimize the effects of acid diffusing from the film, thereby reducing the impact on lithography, and further have excellent removability with HO or an alkaline developer after writing. [Means for solving the problem]

[0018] In order to solve the above problems, the present invention provides: (A) a polyaniline-based conductive polymer having at least one repeating unit represented by the following general formula (1), and (B) a polymer containing at least one addition salt structure represented by the following general formula (2): The present invention provides a conductive polymer composition comprising: [ka] (In the formula, R 1 ~R 4 each independently represents a hydrogen atom, an acidic group, a hydroxy group, an alkoxy group, a carboxyl group, a nitro group, a halogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear, branched or cyclic hydrocarbon group having 1 to 24 carbon atoms and containing a hetero atom, or a linear, branched or cyclic hydrocarbon group having 1 to 24 carbon atoms and partially substituted with a halogen atom. [ka] (In the formula, R 5 , R 6 each independently represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or a linear, branched or cyclic hydrocarbon group containing a hetero atom and having 1 to 24 carbon atoms; X a- is an anion and a indicates the valence.)

[0019] Such a conductive polymer composition can be suitably applied to an antistatic film that exhibits highly efficient charge dissipation in a charged state during electron beam resist writing, thereby improving the positional accuracy of electron beam writing. Furthermore, the conductive polymer composition of the present invention can be suitably used in lithography using an electron beam or the like, thereby enabling the formation of a resist pattern that has high sensitivity, high resolution, and a good pattern shape.

[0020] In addition, the acidic group in the general formula (1) is preferably a sulfo group.

[0021] When the repeating unit represented by the general formula (1) contains an acidic group and the acidic group is a sulfo group, the polyaniline main chain can be efficiently doped with the acidic group to exhibit high electrical conductivity. With such a component (A), the effects of the present invention can be more fully achieved.

[0022] In the structure represented by the general formula (2), X a- It is preferable that the anion represented by the formula (I) is a carboxylate ion.

[0023] As the component (B), in the structure represented by the general formula (2), X a- contains a carboxylate ion, it is possible to reduce the acidity of the polyaniline-based conductive polymer (A) having at least one kind of repeating unit represented by the above general formula (1), and to control the diffusion of acid into an adjacent layer.

[0024] The content of the component (B) is preferably 1 to 200 parts by mass per 100 parts by mass of the component (A).

[0025] By setting the content of the component (B) within this range, it is possible to further reduce acid diffusion from the conductive film formed from the conductive polymer composition to an adjacent layer in contact with it.

[0026] It is also preferable that the conductive polymer composition further contains (C) a nonionic surfactant.

[0027] Such a material can improve the wettability of the conductive polymer composition to a workpiece such as a substrate.

[0028] The content of the component (C) is preferably 0.1 to 10 parts by mass per 100 parts by mass of the component (A).

[0029] Such a material will have better wettability to the surface of the workpiece, and the conductive film will have sufficient conductivity.

[0030] It is also preferable that the conductive polymer composition further contains (D) a water-soluble polymer.

[0031] Such a material can improve the uniformity of the film formed when the conductive polymer composition is formed on a workpiece such as a substrate.

[0032] The content of the component (D) is preferably 30 to 150 parts by mass per 100 parts by mass of the component (A).

[0033] Such a content of component (D) ensures that sufficient antistatic properties are obtained while improving the uniformity of the film.

[0034] The present invention also provides a coated article in which the conductive polymer composition described above is formed as a film on a workpiece.

[0035] The conductive film formed from the conductive polymer composition of the present invention has excellent antistatic properties, and therefore, by coating such an antistatic film on various workpieces, high-quality coated products can be obtained.

[0036] Furthermore, the workpiece is preferably a substrate provided with a chemically amplified resist film.

[0037] The workpiece is preferably a substrate for obtaining a resist pattern by pattern-irradiating it with an electron beam.

[0038] Furthermore, the workpiece is 20 μC / cm 2 It is preferable that the substrate is provided with a chemically amplified electron beam resist film having the above sensitivity.

[0039] Such a workpiece can be preferably used in the present invention.

[0040] In addition, in the present invention, (1) forming an antistatic film on a substrate having a chemically amplified resist film using the conductive polymer composition; (2) pattern-irradiating with electron beams; and (3) A step of developing the resist pattern using H2O or an alkaline developer. The present invention provides a pattern formation method comprising the steps of:

[0041] According to this pattern formation method, it is possible to prevent the electron beam distortion phenomenon caused by charging of the resist surface during electron beam writing, and to obtain a resist pattern with high sensitivity, high resolution, and a good pattern shape. [Effects of the Invention]

[0042] Such a conductive polymer composition can be suitably applied to an antistatic film that exhibits highly efficient charge dissipation in a charged state during electron beam resist writing, thereby improving the positional accuracy of electron beam writing.

[0043] Furthermore, compositions containing component (A) containing a repeating unit represented by general formula (1) and component (B) represented by general formula (2) exhibit high conductivity after film formation on a substrate, have high affinity for HO, good filterability, and good ability to form a flat film on an electron beam resist. They also facilitate stripping with HO or an alkaline aqueous solution after film formation. Such compositions containing components (A) and (B) form conductive films that exhibit good film-forming properties and strippability with HO or an alkaline aqueous solution, as well as high conductivity, i.e., low surface resistivity (Ω / □). These compositions provide high positional accuracy and good resist pattern shape in electron beam writing on resists, and antistatic films that are free of peeled debris or insoluble residues on the resist pattern after resist development, making them suitable for use in electron beam lithography.

[0044] Furthermore, component (B) can control the effect of acid diffusion from the film formed by the composition to adjacent layers, thereby providing high conductivity and antistatic properties with a high charge dissipation ability, as well as providing excellent resist lithography after peeling.

[0045] The composition of the present invention containing components (A) and (B) exhibits good post-film strippability with HO or an alkaline aqueous solution. In the electron beam lithography and patterning process for electron beam resists, films formed from the composition can be stripped with HO before post-lithography heat treatment. Furthermore, they can also be stripped with an alkaline aqueous solution (alkaline developer) in the resist pattern development step after post-lithography heat treatment, just like the eluted portions of the resist pattern. This ease of film stripping with HO or an alkaline aqueous solution also contributes to the reduction of microscopic defects resulting from film-forming material residues during the stripping step after electron beam lithography.

[0046] Furthermore, the (C) nonionic surfactant and (D) water-soluble polymer do not inhibit the removability of films formed in the composition containing components (A) and (B) of the present invention with HO or an alkaline aqueous solution. Films formed from compositions containing the (C) nonionic surfactant and (D) water-soluble polymer are easily stripped with HO or an alkaline aqueous solution, and can be stripped with HO before heat treatment after electron beam lithography. Furthermore, in the resist pattern development step in lithography after heat treatment after electron beam lithography, they can also be stripped with an alkaline aqueous solution (alkaline developer) in the same manner as the eluted portions of the resist pattern. This ease of film stripping with HO or an alkaline aqueous solution also effectively reduces microscopic defects resulting from film formation residues in the stripping step after electron beam lithography.

[0047] Furthermore, by coating various workpieces with an antistatic film formed using the conductive polymer composition of the present invention, high-quality coated products can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0048] As described above, there has been a demand for a conductive polymer composition that can be suitably used for highly conductive antistatic films in resist lithography using electron beams or the like, that can form conductive films with good film quality through favorable coating and film-forming properties on substrates, that has excellent releasability with HO or alkaline aqueous solutions, that exhibits antistatic properties with high charge dissipation capabilities, that does not require the use of a strong base to control the diffusion of acid generated from the film into adjacent layers, and that can be suitably used for highly conductive antistatic films in resist lithography using electron beams or the like.

[0049] Highly conductive polyaniline compounds made solely from component (A) exhibit acidic properties due to the presence of sulfo groups that are not consumed by the dope. When a liquid material made solely from component (A) is applied to an electron beam resist as an antistatic film for electron beam irradiation, the acid diffuses into the resist layer, adversely affecting lithography. Furthermore, adding a strong base such as hydroxide as a neutralizing agent to control the acid diffusion makes precise neutralization difficult. Furthermore, when the composition is applied to an electron beam resist as an antistatic film for electron beam irradiation, excess strong base in the film penetrates the resist layer and causes side reactions with nucleophilic attack sites such as ester bonds in the resist base polymer or acid generator, or reacts with the acid generated from the acid generator in the resist after imaging, adversely affecting imaging sensitivity and post-development lithography.

[0050] In Patent Document 6, various carboxylic acid salts are added to the strong base to cause ion exchange with the sulfo groups in the composition that are not consumed by the doping of the polyaniline compound, liberating the weakly acidic carboxylic acid, thereby reducing the acidity of the composition. However, since the carboxylic acid liberated after ion exchange is itself a weak acid, it does not undergo side reactions with the base polymer of the electron beam resist or cause functional inhibition. However, because the original carboxylic acid salt is a monomer, the salt in the union-exchanged state migrates and diffuses into the resist layer during thermal film formation of the conductive composition, during resist PEB, and even during long-term storage of a substrate with a film formed on top of the resist. This reduces the presence of carboxylic acid salts that actually function within the conductive composition film, and the diffusion of acid components derived from the sulfo groups of the polyaniline compound into the resist cannot be fully controlled. While this effect may be minimal depending on the resist pattern, it can be problematic in lithography processes that leave isolated resist patterns in large drawing areas, such as iso-patterns in positive resists. G When roughness or a substrate having a conductive composition formed on the resist layer is stored for a long period of time, the resist pattern after development deteriorates and the limiting resolution drops significantly.

[0051] As a result of extensive research into the above-mentioned problems, the present inventors have found that by applying a composition containing, as component (A), a polyaniline-based conductive polymer containing a repeating unit represented by the above general formula (1), and as component (B), a polymer having at least one of the addition salt structures represented by the above general formula (2), onto the resist during electron beam irradiation of the resist, an antistatic film can be formed which has good film-forming properties, film quality, and film flatness, low surface resistivity (Ω / □), i.e., high conductivity, good strippability with HO or an alkaline aqueous solution, and in which the diffusion of acid generated from component (A) into the resist is controlled.

[0052] Furthermore, it has been found that by adding (C) a nonionic surfactant and / or (D) a water-soluble polymer to the conductive polymer dispersion, the wettability of the composition containing the polyaniline conductive polymer of component (A) containing a repeating unit represented by general formula (1) above and the polymer of component (B) represented by general formula (2) above to the surface of the workpiece is further improved, thereby improving film-forming properties and film uniformity.

[0053] Furthermore, the conductive polymer composition of the present invention that is suitable for use in the above-mentioned applications can be obtained, for example, by mixing a polyaniline-based polymer as component (A), a polymer and solvent as component (B), and optionally a nonionic surfactant as component (C) and a water-soluble polymer as component (D), and filtering the mixture through a filter, etc. Furthermore, coated articles and substrates that have a thin film formed using the conductive polymer composition of the present invention can be obtained, for example, by applying the conductive polymer composition of the present invention to a substrate and subjecting it to heat treatment, IR or UV irradiation, etc.

[0054] That is, the present invention provides: (A) a polyaniline-based conductive polymer having at least one repeating unit represented by the following general formula (1), and (B) a polymer containing at least one addition salt structure represented by the following general formula (2): The conductive polymer composition comprises: [ka] (In the formula, R 1 ~R 4 each independently represents a hydrogen atom, an acidic group, a hydroxy group, an alkoxy group, a carboxyl group, a nitro group, a halogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear, branched or cyclic hydrocarbon group having 1 to 24 carbon atoms and containing a hetero atom, or a linear, branched or cyclic hydrocarbon group having 1 to 24 carbon atoms and partially substituted with a halogen atom. [ka] (In the formula, R 5 , R 6 each independently represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or a linear, branched or cyclic hydrocarbon group containing a hetero atom and having 1 to 24 carbon atoms; X a- is an anion and a indicates the valence.)

[0055] The present invention will be explained in more detail below, but the present invention is not limited thereto.

[0056] <Conductive polymer composition> The present invention provides a conductive polymer composition comprising (A) a polyaniline-based conductive polymer having at least one type of repeating unit represented by general formula (1) and (B) a polymer containing at least one type of addition salt structure represented by general formula (2).

[0057] [Component (A)] The polyaniline-based conductive polymer of component (A) contained in the conductive polymer composition of the present invention is a polyaniline-based conductive polymer having at least one type of repeating unit represented by the following general formula (1). [ka] (In the formula, R 1 ~R 4each independently represents a hydrogen atom, an acidic group, a hydroxy group, an alkoxy group, a carboxyl group, a nitro group, a halogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear, branched or cyclic hydrocarbon group having 1 to 24 carbon atoms and containing a hetero atom, or a linear, branched or cyclic hydrocarbon group having 1 to 24 carbon atoms and partially substituted with a halogen atom.

[0058] The polyaniline-based conductive polymer is a π-conjugated polymer, which is an organic polymer whose main chain is composed of aniline or a derivative of aniline other than a para-substituted derivative. 1 ~R 4 It is preferable that the component (A) is a polymer containing a repeating unit (aniline monomer) represented by the above general formula (1), in which at least one of R is an acidic group. Among the acidic groups, a sulfo group is more preferable. In addition, from the viewpoints of high affinity to HO, highly efficient filterability, releasability to HO or an alkaline developer after film formation, low defects in lithography, ease of polymerization, low re-aggregation during storage, and stability in air, it is preferable that the component (A) is a polymer containing a repeating unit (aniline monomer) represented by the above general formula (1), in which at least one of R is an acidic group. 1 ~R 4 It is desirable to introduce a hydrophilic substituent other than a sulfo group into the conductive polymer. Examples of the hydrophilic substituent include an alkoxy group, a carboxyl group, and a hydroxyl group. A self-doped, i.e., intramolecularly doped, polyaniline-based conductive polymer having at least one repeating unit having a sulfo group and a hydrophilic substituent is particularly effective.

[0059] Furthermore, the component (A) may exhibit a conductive function by doping with an acid substituent within the molecule, or by supplementary doping with an extramolecular acid or a dopant such as a halogen ion.

[0060] Specific examples of the sulfonate-substituted aniline include alkyl group-substituted aminobenzenesulfonic acids such as o-, m-aminobenzenesulfonic acid, methylaminobenzenesulfonic acid, ethylaminobenzenesulfonic acid, n-propylaminobenzenesulfonic acid, isopropylaminobenzenesulfonic acid, n-butylaminobenzenesulfonic acid, sec-butylaminobenzenesulfonic acid, and t-butylaminobenzenesulfonic acid; alkoxyaminobenzenesulfonic acids such as methoxyaminobenzenesulfonic acid, ethoxyaminobenzenesulfonic acid, and propoxyaminobenzenesulfonic acid; hydroxy-substituted aminobenzenesulfonic acids; nitro group-substituted aminobenzenesulfonic acids; halogen group-substituted aminobenzenesulfonic acids such as fluoroaminobenzenesulfonic acid, chloroaminobenzenesulfonic acid, and bromoaminobenzenesulfonic acid; and di-sulfonate-substituted anilines such as aniline 2-6-disulfonic acid and aniline 3-5-disulfonic acid.

[0061] The sulfonate-substituted anilines may be used singly or in any combination of two or more. From the viewpoints of the HO affinity, electrical conductivity, and product stability of the polyaniline formed from these sulfonate-substituted anilines, alkoxyaminobenzenesulfonic acids and hydroxy-substituted aminobenzenesulfonic acids are preferably used.

[0062] The polyaniline-based conductive polymer of component (A) has a repeating unit R represented by the general formula (1) above. 1 ~R 4 It can also be formed by copolymerizing an aniline having at least one of the groups substituted with a sulfo group with an aniline having no sulfo group.

[0063] Specific examples of anilines having no sulfo group include aniline, 2-methoxyaniline, 2-isopropoxyaniline, 3-methoxyaniline, 2-ethoxyaniline, 3-ethoxyaniline, 3-isopropoxyaniline, 3-hydroxyaniline, 2,5-dimethoxyaniline, 2,6-dimethoxyaniline, 3,5-dimethoxyaniline, 2,5-diethoxyaniline, 2-methoxy-5-methylaniline, 5-tert-butyl-2-methoxyaniline, 2-hydroxyaniline, and 3-hydroxyaniline.

[0064] Among them, aniline, 2-methoxyaniline, 3-methoxyaniline, 2-ethoxyaniline, 3-ethoxyaniline, 2-isopropoxyaniline, 3-isopropoxyaniline, and 3-hydroxyaniline are preferred as the R 1 ~R 4 Even when copolymerized with an aniline monomer in which at least one of the groups is a sulfo group, the affinity for H2O is not lost, and it is preferably used in terms of conductivity, reactivity, and product stability.

[0065] In the polyaniline-based conductive polymer of component (A) used in the present invention, among the repeating units described above, methoxyaminobenzenesulfonic acids are preferred from the viewpoints of solubility, conductivity, and raw material cost, and among these, 3-amino-4-methoxybenzenesulfonic acid is particularly preferred. Furthermore, a copolymer containing two repeating units, 3-amino-4-methoxybenzenesulfonic acid and unsubstituted aniline, is even more preferred. Furthermore, the coexisting base during polymerization is preferably pyridine from the viewpoints of handling, cost, basicity, and non-toxicity to resist components. Even after polymerization and formation, pyridine remains in the polymer as a residual ion, and when the composition is coated on an electron beam resist, it minimizes the impact on lithography.

[0066] [(B) Component] The component (B) contained in the conductive polymer composition of the present invention is a polymer containing at least one of the addition salt structures represented by the following general formula (2). [ka] (In the formula, R 5 , R 6 each independently represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or a linear, branched or cyclic hydrocarbon group containing a hetero atom and having 1 to 24 carbon atoms; X a- is an anion and a indicates the valence.)

[0067] In the structure represented by the general formula (2), preferred R 5 , R 6 Specific examples of the alkyl group include a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, various butyl groups, a 2-hydroxyethyl group, a 2-hydroxypropyl group, a 3-hydroxypropyl group, a cyclohexyl group, a benzyl group, and a phenethyl group.

[0068] In the structure represented by the general formula (2), X a- represents an anion and a represents a valence. That is, 1 / a X in the above general formula (2) a- is the anion X a- a cations N for one + It also shows that X exists. a- The anion represented by the formula (I) is not particularly limited, but is preferably a halogen ion, a methyl sulfate ion, an ethyl sulfate ion, or a carboxylate ion such as an acetate ion, and more preferably a carboxylate ion.

[0069] The component (B) contained in the conductive polymer composition of the present invention is described in detail as structural unit (I) in Patent Document 7, and can be purchased from Nittobo Medical Co., Ltd. as the polyamine series (PAS) or polyallylamine (PAA (registered trademark)) series.

[0070] As a specific example of the structure of the above general formula (2), the following addition salt structure is preferred. [ka]

[0071] For ease of handling, it is preferable that component (B) be highly water-soluble. Furthermore, when a composition is formed from the polyaniline-based conductive polymer (component (A)) and component (B), ion exchange occurs between components (A) and (B) to form associations, which increases the molecular weight and reduces particle dispersibility, preventing particle aggregation and sedimentation. Therefore, component (B) is preferably highly water-soluble and has a molecular weight (Mw) of 40,000 or less, and more preferably 20,000 or less. The molecular weight can be measured as the weight-average molecular weight (Mw) in terms of polystyrene using gel permeation chromatography (GPC).

[0072] [Other ingredients] (surfactant) In the present invention, a surfactant may be added to improve wettability of the conductive polymer to a substrate or other workpiece. Examples of such surfactants include nonionic, cationic, and anionic surfactants. However, nonionic surfactants (C) are particularly preferred due to the stability of the conductive polymer. Specific examples include nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene carboxylic acid esters, sorbitan esters, polyoxyethylene sorbitan esters, and acetylene glycols. Cationic surfactants include alkyltrimethylammonium chloride and alkylbenzylammonium chloride. Anionic surfactants include alkyl or alkylaryl sulfates, alkyl or alkylaryl sulfonates, and dialkyl sulfosuccinates. Amphoteric surfactants include amino acid and betaine types.

[0073] Such a material can improve the wettability of the conductive polymer composition to a workpiece such as a substrate.

[0074] (Water-soluble polymer) In the present invention, a water-soluble polymer (D) may be further added to improve the uniformity of the film formed on a substrate or other workpiece. Such a water-soluble polymer is preferably a homopolymer or copolymer of a hydrophilic repeating unit. Furthermore, such a hydrophilic repeating unit preferably has a vinyl group as a polymerizable functional group, and further preferably is a compound containing a nitrogen atom in the molecule in order to control the diffusion of the acid generated from component (A). Specifically, polyvinylpyrrolidone and the like are preferred.

[0075] In this case, it is preferable that the nitrogen atom in the molecule does not have nucleophilicity, as this avoids the risk of side reactions with nucleophilically attacked functional groups such as ester groups contained in the resist polymer or acid generator in the resist composition, as described above. Therefore, the repeating unit is preferably a nitrogen-containing heterocyclic compound rather than one having a nitrogen atom at the terminal, such as an acrylamide. Furthermore, in this case, it is more preferable that the nitrogen atom is bonded to a vinyl group forming the main chain of the cyclic structure. Examples of such repeating units include N-vinyl-2-pyrrolidone and N-vinylcaprolactam.

[0076] Such a material can improve the uniformity of the film formed when the conductive polymer composition is formed on a workpiece such as a substrate.

[0077] <Method of manufacturing polyaniline-based conductive polymer> Patent Document 4 (Japanese Patent Publication No. 3631910) proposes a self-doped sulfonated polyaniline that exhibits conductivity without forming a complex with a dopant or polymer dopant, and a method for its synthesis. Previously, most polyaniline materials contained dopants, but these were insoluble in almost all organic solvents. The purified polymers generally had low solubility in HO. Even when they could be dispersed in HO using a polymer dopant, they still had particulate properties. This made it difficult to remove particle aggregates, which could cause defects in applications such as electronic device light-transmitting films and semiconductor-related thin film formation. Furthermore, filtration, a method typically used to purify polymers, often resulted in fluctuations in the solids content due to the aggregates being filtered out by the filter, and there was also a limit to how small the filter pore size could be reduced, making stable production difficult.

[0078] When the component (A) used in the present invention is a self-doping polyaniline, the repeating unit represented by the general formula (1) (i.e., component (A)) can be obtained by adding an oxidizing agent to an aqueous solution or a mixed solution of water and an organic solvent and then carrying out oxidative polymerization. The polymerization method for component (A) can be any known method and is not particularly limited. Specifically, the monomer for obtaining the repeating unit represented by the general formula (1) can be polymerized by various synthesis methods, such as chemical oxidation and electrolytic oxidation. Examples of such methods include those described in Japanese Patent Publication Nos. 3,154,460 and 2,959,968.

[0079] In this way, the polyaniline-based conductive polymer of component (A) produced by the above polymerization method is soluble in both HO and organic solvents due to its molecular properties, making it easy to purify by filtration. In addition, the generation of aggregates that cause defects is reduced, improving the efficiency of removal by filtration.

[0080] As the polymerization initiator used in the polymerization of component (A), peroxodisulfates (persulfates) such as ammonium peroxodisulfate (ammonium persulfate), sodium peroxodisulfate (sodium persulfate), and potassium peroxodisulfate (potassium persulfate), peroxides such as hydrogen peroxide and ozone, organic peroxides such as benzoyl peroxide, oxygen, and the like can be used.

[0081] The reaction solvent used in the oxidative polymerization can be water or a mixed solvent of water and a solvent. The solvent used here is preferably a solvent that is miscible with water and can dissolve or disperse components (A) and (B).For example, alcohols such as methanol, ethanol, propanol, and butanol, ethylene glycol, propylene glycol, 1,3-propanediol, dipropylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, D-glucose, D-glucitol, isoprene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,9-hexanediol, and the like. Polyhydric aliphatic alcohols such as nanediol and neopentyl glycol, chain ethers such as dialkyl ethers, ethylene glycol monoalkyl ethers, ethylene glycol dialkyl ethers, propylene glycol monoalkyl ethers, propylene glycol dialkyl ethers, polyethylene glycol dialkyl ethers, and polypropylene glycol dialkyl ethers, cyclic ether compounds such as dioxane and tetrahydrofuran, cyclohexanone, methyl amyl ketone, ethyl acetate, butanediol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, butanediol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, t-butyl acetate, t-propionate Examples of suitable solvents include polar solvents such as butyl, propylene glycol mono-t-butyl ether acetate, γ-butyrolactone, N-methyl-2-pyrrolidone, N,N'-dimethylformamide, N,N'-dimethylacetamide, dimethyl sulfoxide, and hexamethylene phosphortriamide; carbonate compounds such as ethylene carbonate and propylene carbonate; heterocyclic compounds such as 3-methyl-2-oxazolidinone; and nitrile compounds such as acetonitrile, glutaronitrile, methoxyacetonitrile, propionitrile, and benzonitrile.These solvents may be used alone or in combination of two or more. The amount of these water-miscible solvents is preferably 50% by mass or less of the total reaction solvents.

[0082] Polymerization of the polyaniline-based conductive polymer (component A) can be carried out by dissolving the monomers required to obtain the repeating units represented by the general formula (1) in a solvent and then adding a polymerization initiator dropwise. However, if the monomer has low solubility, the initial concentration may be low in order to form a homogeneous reaction system. This decrease in initial concentration can slow down the polymerization reaction, and the resulting polymer may not have the molecular weight required for sufficient conductivity or film-forming properties. Therefore, it is desirable to add a base to the monomer to form a salt with the sulfo group in the monomer, thereby increasing the solubility and carrying out the polymerization.

[0083] The initial concentration of the monomer in the polymerization to obtain the repeating unit of the general formula (1) is preferably 1.0 to 2.0 mol / L, and more preferably 1.5 to 1.8 mol / L.

[0084] The repeating unit represented by the general formula (1) is preferably oxidatively polymerized with an oxidizing agent in the presence of a base. The sulfo group in the monomer for obtaining the repeating unit of the general formula (1) in the polymerization forms a salt with the base. The acidity of the solution at this time is preferably pH<7.0.

[0085] During the polymerization, a base, such as an organic cation represented by the following general formula (4) or an alkali metal or alkaline earth metal ion, coexists in an aqueous solution or a mixed solution of water and an organic solvent, and forms a salt with the acidic group in the repeating unit of the general formula (1).

[0086] The organic cation represented by the following general formula (4) is preferably ammonia, an aliphatic amine, a cyclic saturated amine, or a cyclic unsaturated amine that is produced by contact with an acid. [ka] (In the formula, R 201 , R 202 , R 203 , R 204 R each represents a hydrogen atom, a linear, branched, or cyclic alkyl group, alkenyl group, oxoalkyl group, or oxoalkenyl group having 1 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group or aryloxoalkyl group having 7 to 12 carbon atoms, and some or all of the hydrogen atoms in these groups may be substituted with alkoxy groups. 201 and R 202 , R 201 and R 202 and R 204 may form a ring, and when a ring is formed, R 201 and R 202 and R 201 and R 202 and R 204 represents an alkylene group having 3 to 10 carbon atoms, or a heteroaromatic ring having a nitrogen atom in the ring.

[0087] The polyaniline-based conductive polymer (A) thus polymerized is filtered and isolated as a precipitate in the reaction solution. Filtration methods include vacuum filtration, pressure filtration, centrifugation, and centrifugal filtration, but vacuum filtration is preferred due to its simplicity and adaptability to large-scale synthesis. The filtered precipitate can be washed with a poor solvent on the funnel.

[0088] Furthermore, the polyaniline-based conductive polymer of component (A) obtained in this manner can be dried and then dissolved again in H2O, and impurities can be removed by a technique such as ultrafiltration.

[0089] Ultrafiltration methods include pressure methods and cross-flow methods, but the use of cross-flow methods is preferred from the viewpoint of productivity and the scale of the purified material. Even with the cross-flow method, depending on the formulation, there are continuous circulation methods (purification is controlled by time, and the raw solution is diluted by adding a solvent as needed to deal with the increased viscosity caused by concentration during the purification process) and sequential treatment methods (in purifying the raw solution, when it has been concentrated to twice its original concentration, a step of diluting it to the original concentration is considered as one step, and this step is repeated until the desired degree of purification is achieved), and either method can be used.

[0090] The membrane structures used for ultrafiltration include flat membranes, hollow fiber membranes, tubular membranes, and spiral membranes, and the separation membrane materials include cellulose, cellulose acetate, polysulfone, polypropylene, polyester, polyethersulfone, and polyvinylidene fluoride. There are no restrictions on the combinations that can be used in this step, but when the solvent for the purified material is HO or an acidic solution, a polyethersulfone separation membrane is desirable, and the membrane structure is preferably a hollow fiber membrane from the standpoint of the scale of the treated liquid and treatment efficiency.

[0091] Considering that the substances to be removed in the ultrafiltration step are small molecules such as unreacted substances and polymerization by-products, the molecular weight cutoff of the membrane is preferably in the range of 1,000 to 150,000, and more preferably in the range of 5,000 to 30,000.

[0092] In this case, the purified stock solution is concentrated to twice the concentration, and in consideration of the efficiency of dialysis using a filtration membrane, the stock solution concentration is preferably 0.5 to 1.5% by weight.

[0093] When purification is performed using the cross-flow sequential ultrafiltration method, impurity ions can be quantified in the filtrate at each stage using ion chromatography. The ions that can be quantified in this analysis include SO4 2- , NH4 + , Na +However, other ions can also be quantified as appropriate. SO4 2- , NH4 + , Na + The concentration is preferably 10 ppm or less, and more preferably 1 ppm or less.

[0094] The polyaniline-based conductive polymer of component (A) purified by ultrafiltration is in the form of a solution in HO at the end of the purification process, but can be purified again by precipitation using a water-soluble poor solvent such as acetone. The precipitated polyaniline-based conductive polymer of component (A) is filtered under reduced pressure, and the filtered sediment can be washed again using a poor solvent.

[0095] <Method of manufacturing conductive polymer composition> The conductive polymer composition of the present invention that is suitable for use in the above-mentioned applications can be obtained, for example, by mixing a polyaniline-based polymer as component (A), a polymer and a solvent as component (B), and optionally a nonionic surfactant as component (C) and a water-soluble polymer as component (D), and filtering the mixture with a filter or the like.

[0096] In this case, it is preferable to use HO as the main solvent in order to be able to dissolve the polyaniline-based conductive polymer (component (A)) and the polymer (component (B)) of the present invention, and optionally the nonionic surfactant (component (C)) and the water-soluble polymer (component (D)), and further to prevent mixing with the resist layer when forming a film on an electron beam resist and to minimize adverse effects on lithography.

[0097] The solid content of component (A) in the composition depends on the charge dissipation properties and film thickness required for an electron beam resist antistatic film, but in view of peeling immediately after electron beam writing or highly efficient peeling during development, it is preferably 0.05 to 2.0 wt%, and even more preferably 0.1 to 1.5 wt%.

[0098] In this case, the content of component (B) is preferably 1 to 200 parts by mass per 100 parts by mass of component (A), more preferably 20 to 200 parts by mass per 100 parts by mass of component (A), even more preferably 40 to 150 parts by mass per 100 parts by mass of component (A), and particularly preferably 60 to 120 parts by mass.

[0099] By setting the contents of component (A) and component (B) in this range, acid diffusion from the conductive film formed from the conductive polymer composition to an adjacent layer in contact with it can be further reduced. When the workpiece on which such a conductive film is formed is a substrate equipped with a chemically amplified resist film and the objective is to provide an antistatic effect during electron beam writing, the conductive film not only exhibits an antistatic effect and improves the precision of the writing position, but also reduces the effect of acid diffusion from the conductive film to the resist, allowing a high-resolution resist pattern to be obtained.

[0100] Furthermore, when (C) a nonionic surfactant is added, its content is preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass, per 100 parts by mass of component (A).

[0101] Furthermore, when (D) a water-soluble polymer is added, its content is preferably 30 to 150 parts by mass, and more preferably 90 to 120 parts by mass, per 100 parts by mass of component (A).

[0102] The conductive polymer composition as described above has good filterability and coatability, and can form an antistatic film suitable for electron beam lithography.

[0103] The conductive polymer composition thus obtained can be applied to an electron beam resist, a substrate, or other workpiece by various methods to form an antistatic film. Specific examples include application using a spin coater or the like, a bar coater, immersion, comma coating, spray coating, roll coating, screen printing, flexographic printing, gravure printing, and inkjet printing. After application, a conductive film can be formed by heat treatment using a hot air circulating oven or a hot plate, or by IR or UV irradiation.

[0104] Furthermore, the conductive polymer composition of the present invention can be suitably used not only for antistatic films related to lithography but also as a material for forming laminated films as device components in organic thin-film devices. Furthermore, due to its excellent conductivity, film-forming properties, and transparency, it can be suitably used as a material for forming electrode films for transparent electrodes in organic EL displays, organic EL lighting, solar cells, etc., or as a material for forming carrier transport films for carrier injection layers and carrier transport layers in organic EL displays, organic EL lighting, solar cells, etc., due to its property of exhibiting highly efficient carrier transport derived from a π-conjugated network.

[0105] When the conductive polymer composition of the present invention contains component (B), even when the composition is used as a forming layer in a multilayer structure in the construction of an organic thin film device, the composition does not have an adverse effect due to acid on adjacent layers in the laminate structure. Therefore, even after the device is constructed, it is possible to avoid alteration at the interface of the constituent materials of adjacent layers, side reactions due to acid, and deterioration.

[0106] <Coated products> The present invention also provides a coated article in which the conductive polymer composition of the present invention is formed on a workpiece. Since the conductive film formed from the conductive polymer composition of the present invention has excellent antistatic properties, high-quality coated articles can be obtained by coating such an antistatic film on various workpieces.

[0107] Examples of the workpiece include glass substrates, quartz substrates, photomask blank substrates, resin substrates, silicon wafers, compound semiconductor wafers such as gallium arsenide wafers and indium phosphide wafers, and flexible substrates such as resin films, ultra-thin glass films and metal foils. Furthermore, the surface of these substrates may be coated with an organic or inorganic thin film layer for the purposes of planarization, insulation, and prevention of gas or moisture permeation.

[0108] Examples of coated articles coated with a conductive film obtained using the conductive polymer composition of the present invention include glass substrates, resin films, photoresist substrates, etc. coated with the conductive polymer composition of the present invention for use as an antistatic film.

[0109] Furthermore, since the conductive polymer composition of the present invention is suitable for an independent antistatic film peeling step in an electron beam resist writing process or for an antistatic film peeling step included in a development step, it can be suitably used even when the workpiece is a substrate provided with a chemically amplified resist film, and even more suitable results can be obtained when the workpiece is a substrate for obtaining a resist pattern by patternwise irradiating with electron beams. 2 The substrate may be provided with a chemically amplified electron beam resist film having the above sensitivity.

[0110] <Pattern formation method> Furthermore, the present invention provides (1) forming an antistatic film on a substrate provided with a chemically amplified resist film using the conductive polymer composition of the present invention; (2) pattern-irradiating with electron beams; and (3) A step of developing the resist pattern using H2O or an alkaline developer. The present invention provides a pattern formation method comprising the steps of:

[0111] The pattern formation method can be carried out in the usual manner except for using the conductive polymer composition of the present invention, and the antistatic film formed from the conductive polymer composition may be peeled off with HO after electron beam writing and before heat treatment, or may be peeled off with a developer in a resist pattern development step after heat treatment. After resist pattern development, an etching step and various other steps may of course be carried out.

[0112] According to such a pattern forming method, it is possible to prevent charging during exposure, and to obtain a pattern having high sensitivity, high resolution, and a good pattern shape. [Example]

[0113] The present invention will be specifically explained below using Production Examples, Examples, and Comparative Examples, but the present invention is not limited to these.

[0114] [Synthesis of self-doped polyaniline-based conducting polymers] (Production Example) Synthesis of Polyaniline-Based Conductive Polymer 114.1 g of ammonium peroxodisulfate was dissolved in 400 ml of an acetonitrile / HO mixture (acetonitrile / HO = 1 / 1) and cooled to 0 °C. 96.3 g of 3-amino-4-methoxybenzenesulfonic acid and 4.66 g of aniline were completely dissolved in 300 ml of an acetonitrile / HO mixture (acetonitrile / HO = 1 / 1) of 2 mol / L pyridine and cooled to 0 °C. This solution was added dropwise at a rate of 1.5 ml / min. After the entire addition was completed, the reaction system was heated to 25 °C and stirred for 12 hours. After stirring, the precipitate was filtered using a Buchner funnel, washed with methanol, and dried to obtain 45 g of powdered conductive polymer. The conductive polymer thus obtained was redissolved in HO to a concentration of 1.0 wt% and ultrafiltered (hollow fiber, MWCO = 1000) to remove the NH4 + , SO4 2- The purification was continued until the ion concentration reached 0.1 ppm. The ultrafiltration conditions were as follows: Ultrafiltration membrane molecular weight cutoff: 10K Cross-flow type Feed liquid flow rate: 3,000mL / min Transmembrane partial pressure: 0.12 Pa After concentrating the purified liquid, it was added dropwise to 4,000 mL of acetone to obtain a powder. This powder was again dispersed in 2,000 mL of ultrapure water, and added dropwise to 4,000 mL of acetone to recrystallize the powder. The powder was then dried to obtain a brown conductive polymer.

[0115] Ultrafiltration can be performed using either a continuous circulation method (purification is controlled by time, and solvents are added as needed to dilute the stock solution as it becomes more viscous due to concentration during the purification process) or a sequential processing method (when the stock solution is purified, once it has been concentrated to twice its original concentration, the first step is dilution to the original concentration, and this process is repeated until the desired level of purification is achieved). However, the sequential processing method can be used to observe the progress of impurity ion removal during the purification process. The results of quantitative analysis by ion chromatography of the impurity ion concentrations in the discharged dialysis fluid during purification using the sequential processing method are shown in Table 1. [Table 1]

[0116] [Preparation of Conductive Polymer Composition Containing Polyaniline-Based Conductive Polymer] In preparing each conductive polymer composition, PAS-M-1A (20.0 wt % aqueous solution) and PAA-D19A (20.4 wt % aqueous solution) (both manufactured by Nittobo Medical) were used as component (B), the acetylene glycol-based surfactant Surfynol 465 (manufactured by Nissin Chemical Industry Co., Ltd.) was used as the nonionic surfactant, polyvinylpyrrolidone (manufactured by Nacalai Tesque Inc.) was used as the water-soluble polymer compound, and in the comparative examples, tetra-n-butylammonium hydroxide (10% aqueous solution manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.) and tetra-n-butylammonium acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) were used.

[0117] The structure of PAS-M-1A is as follows: [ka] (In the formula, n represents a positive integer.)

[0118] The structure of PAA-D19A is as follows: [ka] (In the formula, l, m, and n represent positive integers.)

[0119] Example 1 3.00 g of brown powder of the polyaniline-based conductive polymer obtained in the Production Example was dissolved in ultrapure water in which 5.53 g of PAS-M-1A aqueous solution had been dissolved, and the solid content concentration of the polymer was adjusted to 0.15 wt %, and the solution was stirred at room temperature for 2 hours, and then filtered through a hydrophilically treated polyethylene filter to prepare Example 1.

[0120] Example 2 A conductive polymer composition was obtained in the same manner as in Example 1, except that PAS-M-1A in Example 1 was changed to 5.57 g of PAA-D19A.

[0121] Example 3 0.045 g of the acetylene glycol surfactant Surfynol 465 (nonionic surfactant) was dissolved in ultrapure water containing 5.53 g of PAS-M-1A solution, and 3.00 g of the brown powder of the polyaniline conductive polymer obtained in Production Example was further dissolved to adjust the solids concentration of the polymer to 0.15 wt%. After stirring at room temperature for 2 hours, the solution was filtered through a hydrophilic polyethylene filter to prepare Example 3.

[0122] Example 4 A conductive polymer composition was obtained in the same manner as in Example 3, except that PAS-M-1A in Example 3 was changed to 5.57 g of PAA-D19A.

[0123] Example 5 0.045 g of the acetylene glycol surfactant Surfynol 465 (nonionic surfactant) and 3.30 g of polyvinylpyrrolidone (water-soluble polymer compound) were dissolved in ultrapure water containing 5.53 g of PAS-M-1A solution, and 3.00 g of the brown powder of the polyaniline-based conductive polymer obtained in the Production Example was further dissolved to adjust the solids concentration of the polymer to 0.15 wt%. After stirring at room temperature for 2 hours, the solution was filtered through a hydrophilic polyethylene filter to prepare Example 5.

[0124] Example 6 A conductive polymer composition was obtained in the same manner as in Example 5, except that PAS-M-1A in Example 5 was changed to 5.57 g of PAA-D19A.

[0125] (Comparative Example 1) 3.00 g of brown powder of the polyaniline-based conductive polymer obtained in Production Example was dissolved in ultrapure water in which 5.16 g of tetra-normal-butylammonium hydroxide had been dissolved, and the solid content concentration of the polymer was adjusted to 0.15 wt %, and the solution was stirred at room temperature for 2 hours, and then filtered through a hydrophilically treated polyethylene filter to obtain Comparative Example 1.

[0126] (Comparative Example 2) A conductive polymer composition was obtained in the same manner as in Comparative Example 1, except that the tetra-normal-butylammonium hydroxide in Comparative Example 1 was changed to 0.60 g of tetra-normal-butylammonium acetate.

[0127] (Comparative Example 3) 0.045 g of the acetylene glycol surfactant Surfynol 465 (nonionic surfactant) was dissolved in ultrapure water containing 5.16 g of tetra-normal-butylammonium hydroxide, and 3.00 g of the brown powder of the polyaniline conductive polymer obtained in Production Example was further dissolved therein to adjust the solids concentration of the polymer to 0.15 wt%. After stirring at room temperature for 2 hours, the solution was filtered through a hydrophilic-treated polyethylene filter to prepare Comparative Example 3.

[0128] Comparative Example 4 A conductive polymer composition was obtained in the same manner as in Comparative Example 3, except that the tetra-normal-butylammonium hydroxide in Comparative Example 3 was changed to 0.60 g of tetra-normal-butylammonium acetate.

[0129] (Comparative Example 5) 0.045 g of the acetylene glycol surfactant Surfynol 465 as a nonionic surfactant and 3.30 g of polyvinylpyrrolidone as a water-soluble polymer compound were dissolved in ultrapure water containing 5.16 g of tetra-normal-butylammonium hydroxide, and 3.00 g of the brown powder of the polyaniline-based conductive polymer obtained in Production Example was further dissolved therein to adjust the solids concentration of the polymer to 0.15 wt%. After stirring at room temperature for 2 hours, the solution was filtered through a hydrophilic-treated polyethylene filter to give Comparative Example 5.

[0130] (Comparative Example 6) A conductive polymer composition was obtained in the same manner as in Comparative Example 5, except that the tetra-normal-butylammonium hydroxide in Comparative Example 5 was changed to 0.60 g of tetra-normal-butylammonium acetate.

[0131] (Evaluation resist) In the evaluation as an antistatic film for electron beam lithography (for electron beam resist), the positive chemically amplified resist used was a positive chemically amplified electron beam resist (RP-1) manufactured by Shin-Etsu Chemical Co., Ltd., and the negative chemically amplified electron beam resist (RP-2) manufactured by Shin-Etsu Chemical Co., Ltd.

[0132] [Positive resist composition (R-1)] Polymer (RP-1) (100 parts by mass), acid generator P-1 (8 parts by mass), acid diffusion controller Q-1 (4 parts by mass), and a surfactant were dissolved in an organic solvent, and each of the resulting solutions was filtered through a 0.02 μm UPE filter to prepare positive resist compositions.

[0133] [Negative resist composition (R-2)] Negative resist compositions were prepared by dissolving polymer (RP-2) (100 parts by mass), acid generator P-1 (5 parts by mass), fluorine-containing polymer D1 (3 parts by mass), diffusion controller Q-1 (7 parts by mass), and a surfactant in an organic solvent, and filtering each of the resulting solutions through a 0.02 μm UPE filter.

[0134] In addition, PF-636 (manufactured by OMNOVA SOLUTIONS) was added to each resist composition as a surfactant, and a mixed solvent of 1,204 parts by mass of propylene glycol monomethyl ether acetate (PGMEA), 1,204 parts by mass of ethyl lactate (EL), and 1,606 parts by mass of propylene glycol monomethyl ether (PGME) was used as the organic solvent.

[0135] [ka]

[0136] [ka]

[0137] [ka]

[0138] [ka]

[0139] [ka]

[0140] (Electron beam resist and conductive polymer composition film deposition on silicon wafer) (R-1) and (R-2) were spin-coated onto a 6-inch (150 mm) diameter silicon wafer using a Coater Developer Clean Track MARK VIII (Tokyo Electron Limited), and baked in a precision incubator at 110°C for 240 seconds to remove the solvent, forming a film. 2.0 mL of each of Examples 1 to 6 and Comparative Examples 1 to 6 was dropped onto the top layer, and then spin-coated over the entire resist film using a spinner. The spin-coating conditions were adjusted to achieve a film thickness of 80±5 nm. The wafer was baked in a precision incubator at 90°C for 5 minutes, and the solvent was removed to obtain an antistatic film. The resist film thickness and antistatic film thickness were determined using a variable angle of incidence spectroscopic ellipsometer VASE (JA Woollam).

[0141] (Conductive polymer composition pH measurement) The pH of the conductive polymer compositions of Examples 1 to 6 and Comparative Examples 1 to 6 was measured using a pH meter D-52 (manufactured by Horiba, Ltd.) The results are shown in Table 2.

[0142] (Volume resistivity of conductive polymer composition) The volume resistivity (Ω·cm) of the conductive polymer films obtained by spin coating in Examples 1 to 6 and Comparative Examples 1 to 6 was measured using a Loresta-GP MCP-T610 or Hiresta-UP MCP-HT450 (both manufactured by Mitsubishi Chemical Corporation). The results are shown in Table 2.

[0143] [Table 2]

[0144] (Evaluation of resist film loss rate) The effects of acid diffusion from the conductive polymer film to the resist film or diffusion of additives into the resist film are particularly evident in the remaining film after development when a positive resist is used. Hereinafter, films of Examples 1 to 6 and Comparative Examples 1 to 6 were formed on a positive resist (R-1), and after electron beam lithography, the formed conductive polymer compositions were subjected to a pre-PEB stripping process or a post-PEB stripping process, and the rate of change in film loss of the resist film was measured when development was performed to obtain a resist pattern.

[0145] Pre-PEB stripping process evaluation A positive chemically amplified resist (R-1) was spin-coated onto a 6-inch silicon wafer using a MARK VIII (Tokyo Electron Limited, Coater Developer Clean Track) and pre-baked on a hot plate at 110°C for 240 seconds to prepare an 80 nm thick resist film (film thickness (T1)). A conductive polymer composition was spin-coated onto the resulting resist-coated wafer using a MARK VIII in the same manner as above, and baked on a hot plate at 90°C for 90 seconds to prepare a 20 nm thick conductive polymer film. The wafer was then exposed using an electron beam exposure system (Hitachi High-Technologies Corporation, HL-800D, accelerating voltage 50 keV), after which the conductive polymer film was peeled off by pouring pure water over it for 15 seconds, followed by a post-exposure bake at 90°C for 240 seconds (PEB), and development was performed using a 2.38 mass% aqueous solution of tetramethylammonium hydroxide, yielding a positive pattern (film thickness in the unexposed area (T3)).

[0146] Post-PEB peeling process evaluation A positive chemically amplified resist (R-1) was spin-coated onto a 6-inch silicon wafer using a MARK VIII (Tokyo Electron Limited, Coater Developer Clean Track) and pre-baked on a hot plate at 110°C for 240 seconds to form an 80 nm resist film (film thickness (T1)). A conductive polymer composition was spin-coated onto the resulting resist-coated wafer using a MARK VIII in the same manner as above, and baked on a hot plate at 90°C for 90 seconds to form a 20 nm conductive polymer film. The wafer was then exposed using an electron beam exposure system (Hitachi High-Technologies Corporation, HL-800D, accelerating voltage 50 keV), followed by baking at 90°C for 240 seconds (PEB: post-exposure bake), and developed in a 2.38 mass% aqueous solution of tetramethylammonium hydroxide, yielding a positive pattern (film thickness in the unexposed area (T3)).

[0147] The same operation as in the post-PEB stripping process was performed on a resist film without a conductive polymer film, and the optimum exposure dose after exposure and development and the resist film thickness (T2) in the unexposed area were determined. The film loss change rate (film thickness change rate) for the pre-PEB stripping process and post-PEB stripping process of the conductive polymer film was calculated using the following formula. Film loss rate (%) = [{(T1-T3)-(T1-T2)} / (T1-T2)] x 100 The results are shown in Table 3.

[0148] [Table 3]

[0149] (Electron beam writing resolution evaluation) The effects of acid diffusion from a conductive polymer film to a resist film, or diffusion of an additive into a resist film, are evident in the pattern resolution limit, pattern edge roughness, and pattern cross-sectional shape after development of writing on a positive resist. Hereinafter, films of Examples 1 to 6 and Comparative Examples 1 to 6 were formed on a positive resist (R-1), and after electron beam writing, the formed conductive polymer compositions were subjected to a pre-PEB stripping process or a post-PEB stripping process. The resolution limit, pattern edge roughness, and pattern cross-sectional shape of the resulting resist patterns were evaluated.

[0150] A resist pattern was obtained from the positive resist film and conductive film formed on the mask blank through the following process.

[0151] Pre-PEB stripping process evaluation The resist composition prepared above was spin-coated using ACT-M (Tokyo Electron Limited) onto a 152 mm square mask blank whose outermost surface was a chromium oxynitride film, and the blank was pre-baked on a hot plate at 110°C for 600 seconds to produce an 80 nm resist film. The thickness of the resulting resist film was measured using an optical measuring device, Nanospec (Nanometrics). Measurements were performed at 81 locations within the surface of the blank substrate, excluding the outer edge portion extending 10 mm inward from the outer periphery of the blank, and the average film thickness and film thickness range were calculated. Each of the conductive polymer compositions of Examples 1 to 6 and Comparative Examples 1 to 6 was spin-coated onto the mask blank with the resist film thus obtained, and the mask blank was baked on a hot plate at 90°C for 90 seconds to produce a 20 nm conductive polymer film. Subsequently, the resist was exposed using an electron beam exposure device (EBM-5000plus manufactured by NuFlare Technology, Inc., accelerating voltage 50 kV), and after rinsing with ultrapure water for 20 seconds and stripping, PEB was performed at 110°C for 600 seconds, and development was performed with a 2.38 mass% TMAH aqueous solution to obtain a pattern of positive resist (R-1).

[0152] The obtained resist patterns were evaluated as follows: The prepared patterned mask blank was observed with a top-down SEM (scanning electron microscope), and the exposure dose required to resolve a 200 nm 1:1 line and space (LS) at 1:1 was determined as the optimum exposure dose (sensitivity) (μC / cm 2 ), the minimum dimension at that exposure dose was taken as the resolution (limiting resolution). Also, for a 200 nm isoline pattern (IL), the minimum dimension at that exposure dose was taken as the resolution (limiting resolution) when the exposure dose at which 200 nm is resolved was taken as the optimal exposure dose.

[0153] In addition, the 200 nm pattern edge roughness (LER) of the line and space (LS) was measured by SEM, and the cross section of the isoline pattern was observed by SEM to determine whether the pattern shape was rectangular or not. The results for the positive resist (R-1) are shown in Table 4.

[0154] [Table 4]

[0155] Post-PEB peeling process evaluation The resist composition prepared above was spin-coated using ACT-M (Tokyo Electron Limited) onto a 152 mm square mask blank whose outermost surface was a chromium oxynitride film, and the blank was pre-baked on a hot plate at 110°C for 600 seconds to produce an 80 nm resist film. The thickness of the resulting resist film was measured using an optical measuring device, Nanospec (Nanometrics). Measurements were performed at 81 locations within the surface of the blank substrate, excluding the outer edge portion extending 10 mm inward from the outer periphery of the blank, and the average film thickness and film thickness range were calculated. Each of the conductive polymer compositions of Examples 1 to 6 and Comparative Examples 1 to 6 was spin-coated onto the mask blank with the resist film thus obtained, and the mask blank was baked on a hot plate at 90°C for 90 seconds to produce a 20 nm conductive polymer film. Subsequently, the resist was exposed using an electron beam exposure device (EBM-5000plus manufactured by NuFlare Technology, Inc., accelerating voltage 50 kV), subjected to PEB at 110°C for 600 seconds, and developed with a 2.38% by mass TMAH aqueous solution to obtain a pattern of positive resist (R-1).

[0156] The obtained resist patterns were evaluated as follows: The prepared patterned mask blank was observed with a top-down SEM (scanning electron microscope), and the exposure dose required to resolve a 200 nm 1:1 line and space (LS) at 1:1 was determined as the optimum exposure dose (sensitivity) (μC / cm 2 ), the minimum dimension at that exposure dose was taken as the resolution (limiting resolution). For a 200 nm isoline pattern (IL), the minimum dimension at that exposure dose was taken as the resolution (limiting resolution) when the optimal exposure dose was used to resolve the pattern at 200 nm. Furthermore, the pattern edge roughness (LER) of the line-and-space pattern (LS) with a line width of 200 nm was measured by SEM, and the cross section of the isoline pattern (IL) was observed by SEM to determine whether the pattern shape was rectangular or not. The results for the positive resist (R-1) are shown in Table 5.

[0157] [Table 5]

[0158] In Table 2, in Examples 1 to 6, the conductive polymer composition contains a polyaniline-based polymer compound (A) as the component (B) containing at least one acetate salt having the structure represented by the general formula (2) above, specifically PAS-M-1A and PAA-D19A manufactured by Nittobo Medical. Therefore, component (B) exhibits ion exchange with the sulfonic acid terminals of component (A), resulting in a pH in the weakly acidic range of 4.38 to 4.93. In Comparative Examples 1, 3, and 5, component (B) is a strongly basic substance, which neutralizes the sulfonic acid terminals of component (A), resulting in a higher pH, close to neutral. Furthermore, in Comparative Examples 2, 4, and 6, the acetate salt monomer exhibits ion exchange with the sulfonic acid terminals of component (A), similar to PAS-M-1A and PAA-D19A, resulting in a pH in the weakly acidic range of 4.75 to 5.10. Because these results are an evaluation of the liquid properties before film formation, they do not directly indicate the effect on the resist when formed as a film on top of the resist in applications as an antistatic film during electron beam resist writing, and the effectiveness of the Examples compared to the Comparative Examples is also unclear. However, when these conductive polymer compositions are applied and formed into a film on electron beam resist, and then undergo electron beam writing and PEB processes, a clear difference in lithography occurs.

[0159] If (B) contains acetate, the conductivity is maintained without promoting the dedoping of the sulfo group involved in the intramolecular doping of component (A), resulting in a volume resistivity on the order of E+02 to E+03 Ω·cm. In contrast, if component (B) is a strongly basic material such as a hydroxide salt, the dedoping of the sulfo group involved in the intramolecular doping of component (A) is caused, resulting in a volume resistivity on the order of E+04 Ω·cm, which is somewhat higher. In Examples 1 to 6 and Comparative Examples 2, 4, and 6, the volume resistivities (Ω·cm) of the conductive polymer films were high enough to fully exhibit antistatic properties. However, in Comparative Examples 1, 3, and 5, the volume resistivities (Ω·cm) were high enough to fail to fully exhibit antistatic properties.

[0160] In Table 3, Examples 1 to 6 and Comparative Examples 1 to 6 were formed on a positive electron beam resist (R-1), and the film loss rates were compared based on the lithography results obtained by developing the resist pattern after a pre-PEB stripping process, or by simultaneous stripping during resist pattern development after PEB. In Examples 1 to 6, regardless of the resist type and stripping process, the resist film loss rate was approximately 5 to 10%, whereas in Comparative Examples 1, 3, and 5 it was approximately 30% to 48%, and in Comparative Examples 2, 4, and 6 it was approximately 15 to 23%, which were significantly higher. While the component (B) in Examples 1 to 6 was little affected by diffusing into the electron beam resist or by chemically reacting with each component, the strongly basic components contained in Comparative Examples 1, 3, and 5 not only neutralized the acid but also diffused into the electron beam resist layer, causing nucleophilic attack on each component of the resist, thereby modifying the resist function. Furthermore, in Comparative Examples 2, 4, and 6, the carboxylate itself diffused into the electron beam resist layer, reducing its presence in the conductive polymer composition, which reduced the ability of the polyaniline to control the diffusion of acid, resulting in a larger resist film loss rate after development.

[0161] Tables 4 and 5 compare the limiting resolution and edge roughness (LER) of the LS pattern and the limiting resolution and pattern cross-sectional shape of the IL pattern at the optimal exposure dose for a pattern width of 200 nm based on the lithography results of Examples 1 to 6 and Comparative Examples 1 to 6, which were formed on a positive electron beam resist (R-1) and then subjected to a pre-PEB stripping process and PEB followed by resist pattern development, or without the pre-PEB stripping process and PEB followed by batch resist pattern development. In Examples 1 to 6, the limiting resolution and edge roughness (LER) of the LS pattern were equivalent to those of lithography using only a resist that was not coated with the conductive polymer composition, and the cross-sectional shape of the IL pattern after development maintained a rectangular shape without impairing resist performance. On the other hand, in Comparative Examples 1, 3, and 5, as described above, the effects of chemical reactions on the various components of the electron beam resist were significant, and the strongly basic substances not only neutralized the acid in the conductive polymer composition, but also caused nucleophilic attacks on the various components of the electron beam resist after film formation, thereby affecting the sensitivity and lithography performance of the electron beam resist.Furthermore, in Comparative Examples 2, 4, and 6, the presence of carboxylate salts in the conductive composition film decreased, resulting in deterioration of the LS and IL pattern resolution, line edge roughness (LER) of the LS pattern, and cross-sectional shape of the IL pattern.

[0162] (Electron beam lithography evaluation and PCD (Post Coating Delay) evaluation) Next, the change over time of the resist film due to the influence of the conductive polymer film before electron beam irradiation was measured. A two-layer film of resist film and conductive polymer film, coated by the method described below, was left in an electron beam lithography system for 7, 14, or 30 days immediately after film formation, and then a resist pattern was obtained by the pre-PEB stripping process or post-PEB stripping process of the conductive polymer film described below. The variation in pattern line width at the same sensitivity was determined relative to the sensitivity when writing was performed immediately after the resist and conductive polymer film were formed.

[0163] Pre-PEB stripping process evaluation A positive chemically amplified resist (R-1) was spin-coated onto a 6-inch silicon wafer using MARK VIII (Tokyo Electron Limited, Coater Developer Clean Track), and the wafer was pre-baked on a hot plate at 110°C for 240 seconds to prepare a resist film with a thickness of 80 nm. A conductive polymer composition was spin-coated onto the resulting wafer with the resist film using MARK VIII in the same manner as above, and the wafer was baked on a hot plate at 90°C for 90 seconds to prepare a conductive polymer film. Resist patterns were obtained from the wafer coated with a two-layer film of resist film and conductive polymer film by the following method immediately after coating, and after 7 days, 14 days, and 30 days. First, the wafer immediately after coating was exposed using an electron beam exposure device (Hitachi High-Technologies Corporation, HL-800D, acceleration voltage 50 keV), then pure water was poured over it for 20 seconds to peel off the conductive polymer film, and the wafer was baked at 110°C for 240 seconds (PEB: post exposure bake), and developed with an aqueous solution of 2.38 mass% tetramethylammonium hydroxide. The patterned wafer was observed with an overhead SEM (scanning electron microscope), and the optimal exposure dose (sensitivity) (μC / cm) was determined as the exposure dose required to resolve 400 nm lines and spaces at a 1:1 ratio. 2 The minimum dimension at this optimum exposure dose was taken as the resolution. Resist patterns were also obtained in the same manner on wafers 7, 14, and 30 days after coating, and the exposure dose (optimum exposure dose (sensitivity) (μC / cm)) at which a 200 nm line and space was resolved at 1:1 on the wafer immediately after coating was determined. 2 The fluctuation of the pattern line width in each of the above was measured. The results are shown in Table 6.

[0164] Post-PEB peeling process evaluation Similar to the pre-PEB stripping process, wafers coated with a two-layer film of resist film and conductive polymer film were prepared. For each wafer that had been coated 7, 14, and 30 days after coating, the wafers were baked at 110°C for 240 seconds (PEB: post exposure bake) without undergoing the process of pouring pure water over the wafer for 20 seconds to strip the conductive polymer film after electron beam exposure. Then, the wafers were developed with an aqueous solution of 2.38% by mass of tetramethylammonium hydroxide to obtain resist patterns. The exposure dose (optimal exposure dose (sensitivity) (μC / cm)) required for 1:1 resolution of 200 nm lines and spaces on the wafers immediately after coating was measured. 2 The fluctuation of the pattern line width in each of the above was measured. The results are shown in Table 7.

[0165] [Table 6]

[0166] [Table 7]

[0167] The negative resist (R-2) was also evaluated in the same manner as the positive resist (R-1) for the pre-PEB stripping process and post-PEB stripping process. The results are shown in Tables 8 and 9.

[0168] [Table 8]

[0169] [Table 9]

[0170] As shown in Tables 6 to 9, the post-coating delay (PCD) evaluation showed that the compositions of Examples 1 to 6, which suppress the influence of acid from the conductive polymer film on the electron beam resist layer, maintained good storage stability of the resist film even after it was deposited as a conductive film on top of the resist. This suggests that the suppression of acid diffusion from the conductive polymer film in the resist film before electron beam lithography and the conductive polymer film (antistatic film) coating on top of it contributes to good lithography results in the processes of lithography, conductive polymer film (antistatic film) stripping, and pattern development. On the other hand, the compositions of Comparative Examples 1, 3, and 5, which contain strong basic substances, exhibit a high neutrality due to their high acidity mitigation (neutralization) efficiency. However, after deposition, unreacted strong basic substances gradually diffuse into the electron beam resist layer, causing nucleophilic attack on resist components, resulting in a side reaction in which acid is generated from the acid generator before lithography. This can adversely affect lithography by generating excess acid during substrate storage or by creating an acid concentration gradient within the layer upon electron beam irradiation. Furthermore, in the compositions of Comparative Examples 2, 4, and 6, the monomolecular carboxylate in the conductive composition film gradually diffuses into the resist layer during storage of the substrate, resulting in a shortage of the amount of polyaniline-derived acid in the conductive composition film that is essentially necessary to control the diffusion of the polyaniline-derived acid into the resist layer, resulting in the adverse effect of the polyaniline-derived acid on resist lithography. The effect on the resist layer in these comparative examples becomes greater the longer the conductive polymer composition is formed as a film on the resist, and the effect is significant even in the pre-PEB stripping process.

[0171] As described above, the conductive polymer composition of the present invention can form an antistatic film that has excellent antistatic properties when patterned onto an electron beam resist and minimizes the effect of acid on the resist. Such a composition that has conductivity and can prevent the effect of acid is also effective as a constituent film of an organic thin film device, and can be suitably used as a device construction material if it can suppress the effect of acid on adjacent layers and function as a conductive material or a carrier transport medium within a laminate structure.

[0172] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention.

Claims

1. (A) a polyaniline-based conductive polymer having at least one repeating unit represented by the following general formula (1), and (B) a polymer containing at least one of the addition salt structures represented by the following general formula (2): and A conductive polymer composition, characterized in that the content of the component (B) is 20 to 60 parts by mass per 100 parts by mass of the component (A). 【Chemical 1】 (In the formula, R １ ~R ４ each independently represents a hydrogen atom, an acidic group, a hydroxy group, an alkoxy group, a carboxyl group, a nitro group, a halogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a linear, branched or cyclic hydrocarbon group having 1 to 24 carbon atoms and containing a hetero atom, or a linear, branched or cyclic hydrocarbon group having 1 to 24 carbon atoms and partially substituted with a halogen atom. 【Chemistry 2】 (In the formula, R ５ , R ６ each independently represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, or a linear, branched or cyclic hydrocarbon group containing a hetero atom and having 1 to 24 carbon atoms; X ａ－ indicates a carboxylate ion and a indicates the valence.)

2. 2. The conductive polymer composition according to claim 1, wherein the acidic group in the general formula (1) is a sulfo group.

3. 3. The conductive polymer composition according to claim 1, further comprising (C) a nonionic surfactant.

4. 4. The conductive polymer composition according to claim 3, wherein the content of the component (C) is 0.1 to 10 parts by mass per 100 parts by mass of the component (A).

5. 5. The conductive polymer composition according to claim 1, further comprising (D) a water-soluble polymer.

6. 6. The conductive polymer composition according to claim 5, wherein the content of the component (D) is 30 parts by mass to 150 parts by mass per 100 parts by mass of the component (A).

7. A coated article, comprising a workpiece on which the conductive polymer composition according to any one of claims 1 to 6 is formed into a film.

8. 8. The coated article according to claim 7, wherein the workpiece is a substrate provided with a chemically amplified resist film.

9. 9. The coated article according to claim 8, wherein the workpiece is a substrate for obtaining a resist pattern by pattern-irradiating an electron beam.

10. The workpiece has a temperature of 20μC / cm ２ 10. The coated article according to claim 9, which is a substrate provided with a chemically amplified electron beam resist film having the above sensitivity.

11. (1) A step of forming an antistatic film on a substrate having a chemically amplified resist film by using the conductive polymer composition according to any one of claims 1 to 6; (2) patternwise irradiation with electron beams; and (3) H ２ a step of developing the resist using O or an alkaline developer to obtain a resist pattern; A pattern forming method comprising the steps of:

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