Resist composition and pattern forming method

Abstract

The invention provides a resist composition. The resist composition comprises matrix resin, a photo-acid generator and an organic solvent, the photoacid generator has anions and cations, the anions in the photoacid generator have a structure as shown in a general formula (1), and the cations in the photoacid generator have a structure as shown in a general formula (2); according to the invention, the internal substituent group of the photo-acid generator is regulated and controlled, so that the resist film shows optical properties of few defects and excellent lithographic printing performance in a lithographic printing technology taking high-energy rays as a light source. # imgabs0 #

Description

Technical Field The present invention relates to a resist composition and a method for forming a resist pattern. Background Art In photolithography, a resist film made of a resist material is usually formed on a substrate, the resist film is selectively exposed, and a development process is performed to form a resist pattern with a predetermined shape on the resist film; Related technology description: In recent years, in the manufacturing process of semiconductor devices or display panels, the advancement of photolithography has led to a more miniaturized pattern. As a miniaturization technology, the wavelength of the exposure light source is generally shortened. For example, KrF excimer lasers and ArF excimer lasers have been mass-produced. Currently, research on exposure light sources is developing towards lower wavelengths such as EUV (extreme ultraviolet), EB (electron beam) and X-rays. With the miniaturization of patterns, the high integration and high speed of LSI, the definition requirements of resist films are becoming more and more stringent. In addition to the lithographic characteristics represented by pattern shape, contrast, MEEF (Mask Error Enhancement Factor), roughness, etc., it is increasingly necessary to further improve the defects of the resist film after development on this basis; for example, defects may be caused by the low solubility of the resist composition such as the photoacid generator in the casting solvent or the incomplete dissolution of the developer after use. Therefore, as a means to improve the performance of the photoacid generator, in the prior art, a method of adding a straight-chain alkyl group, a fluorine atom, or a group with a strong polarity such as a hydroxyl group, or introducing a hexafluoro unit can be selected. However, although the above methods used in the prior art can reduce certain defects, it is still difficult to obtain satisfactory lithographic printing performance. Therefore, a photoacid generator with excellent performance is urgently needed to solve the defects in the above prior art. Summary of the invention In view of the defects in the above-mentioned prior art, the present invention provides a resist composition and a method for patterning using the resist composition. By adjusting the specific substituents in the photoacid generator in the resist composition, it is achieved that in the lithography technology using high-energy rays as the light source, a resist composition with few defects and excellent lithography performance can be provided. The first aspect of the present invention provides a resist composition, comprising a main resin, a photoacid generator and an organic solvent; the photoacid generator has an anion and a cation, and the anion has a structure as shown in the general formula (1): In the general formula (1), R fSaid R4 represents one or more combinations of alkyl groups with carbon atoms of 1 to 4 and fluoroalkyl groups; said R4 represents one or more combinations of monovalent straight-chain hydrocarbon groups with carbon atoms of 1 to 20 which may contain heteroatoms, branched hydrocarbon groups, and cyclic hydrocarbon groups, and / or said R4 comprises one or more combinations of amide bonds, ether bonds, and ester bonds; said R5 represents one or more combinations of monovalent cyclic hydrocarbon groups with carbon atoms of 4 to 8 or adamantyl groups; said n is an integer between 0 and 5. Furthermore, the cation in the photoacid generator has a structure as shown in general formula (2): In the general formula (2), R1, R2, and R3 represent a monovalent straight-chain hydrocarbon group with 1 to 20 carbon atoms, which may contain hydrogen atoms or heteroatoms, or a combination of one or more of a branched hydrocarbon group and a cyclic hydrocarbon group. Furthermore, the main resin has a structure as shown in general formula (3): In the general formula (3), R6 represents one of a hydrogen atom, a fluorine atom, a methyl group and a trifluoromethyl group; R7 represents a hydrogen atom, or a polar group having a structure including one or more of a branched chain, a hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a carbonate bond, a lactone ring, and a carboxylic anhydride. Furthermore, the resist composition further comprises one or more selected from the following components: an acid diffusion inhibitor, an additive, and a fluorine-containing resin. Furthermore, the photoacid generator comprises one of the structures shown below: Preferably, the photoacid generator comprises one of the structures shown below: Furthermore, in the general formula (3) of the main resin, R7 represents one or more combinations of the following groups: Preferably, R7 represents one or more combinations of the following groups: Furthermore, the acid diffusion inhibitor is a combination of one or more of the following compounds: Furthermore, the fluorine-containing resin comprises a polymer having a structural unit represented by the general formula (4): In the general formula (4), R8 and R9 represent hydrogen atoms, halogen atoms, alkane groups with 1 to 5 carbon atoms, or halogenated alkane groups with 1 to 5 carbon atoms, and R8 and R9 are the same or different; 10 It is an organic group containing fluorine atoms; R 11 is a hydrogen atom or a methyl group; Preferably, the fluorine-containing resin comprises the following compounds: Further, the additive is one or more combinations of organic carboxylic acids or oxygen-containing phosphoric acids and their derivatives; Preferably, the additive comprises one or more combinations of acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid, phosphoric acid, phosphonic acid, and phosphinic acid. The second aspect of the present invention provides a pattern forming method, which comprises the steps of coating the resist composition according to any one of claims 1 to 9 on a substrate; after performing a heat treatment before exposure, exposing the substrate through a photomask using any one of high energy rays, electron beams or extreme ultraviolet light with a wavelength of 140 to 250 nm, and after the exposure and heat treatment, developing the substrate using a developer; using an alkaline aqueous solution or an organic solvent as a developer to dissolve the exposed or unexposed portion, thereby obtaining a positive or negative pattern. Beneficial Effects The resist composition involved in the present invention achieves excellent performance in key parameters such as MEF, EL, LWR and CDU in lithography using high-energy rays such as KrF, ArF excimer laser, electron beam (EB) and extreme ultraviolet (EUV) as light sources by specifically adjusting the groups in the photoacid generator. In addition, it also shows lower defects and is more suitable for miniaturized patterning processes to form good rectangular fine patterns. BRIEF DESCRIPTION OF THE DRAWINGS In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work. Figure 1 A schematic diagram of coating the resist composition according to an embodiment of the present invention; Figure 2 It is a schematic diagram of exposure of a resist composition according to an embodiment of the present invention; Figure 3 A schematic diagram of developing a resist composition according to an embodiment of the present invention; Description of Reference Numerals 1: substrate; 2: processed layer; 3: intermediate layer; 4: resist film layer; 5: light. DETAILED DESCRIPTION The following will describe the embodiments of the present invention in detail with reference to the accompanying drawings: In an embodiment of the present invention, a resist composition is provided, comprising a main resin, a photoacid generator and an organic solvent; wherein the photoacid generator has an anion and a cation, and in an embodiment of the present invention, the anion has a structure as shown in general formula (1): In the general formula (1) of the present invention, R f represents one or more combinations of alkyl groups with 1 to 4 carbon atoms and fluoroalkyl groups; R4 represents one or more combinations of monovalent straight-chain hydrocarbon groups with 1 to 20 carbon atoms that may contain heteroatoms, branched hydrocarbon groups, and cyclic hydrocarbon groups, and / or R4 comprises one or more combinations of amide bonds, ether bonds, and ester bonds; R5 represents one or more combinations of monovalent cyclic hydrocarbon groups with 4 to 8 carbon atoms or adamantyl groups; n is an integer between 0 and 5; The cation in the photoacid generator in the embodiment of the present invention has a structure as shown in the general formula (2): In the general formula (2) in the embodiment of the present invention, R1, R2, and R3 represent a monovalent straight-chain hydrocarbon group with 1 to 20 carbon atoms, including hydrogen atoms or heteroatoms, including one or more combinations of branched hydrocarbon groups and cyclic hydrocarbon groups; Preferably, the photoacid generator in the embodiment of the present invention comprises one or more combinations of the following structural compounds: Particularly preferably, the photoacid generator in the embodiment of the present invention comprises one or more combinations of the following structural compounds: The present invention also provides a method for synthesizing the photoacid generator, but the present invention is not limited thereto. The photoacid generator of the present invention can be synthesized according to the following reaction formula. In the above reaction formula, R fIt represents one or more combinations of alkyl groups with carbon atoms of 1 to 4 and fluoroalkyl groups; R4 represents one or more combinations of monovalent straight-chain hydrocarbon groups with carbon atoms of 1 to 20 that may contain heteroatoms, branched hydrocarbon groups, and cyclic hydrocarbon groups, and / or R4 comprises one or more combinations of amide bonds, ether bonds, and ester bonds; R5 represents one or more combinations of monovalent cyclic hydrocarbon groups with carbon atoms of 4 to 8 or adamantyl groups; n is an integer between 0 and 5; R1, R2, and R3 represent one or more combinations of monovalent straight-chain hydrocarbon groups with carbon atoms of 1 to 20 that may contain hydrogen atoms or heteroatoms, branched hydrocarbon groups, and cyclic hydrocarbon groups. The above reaction formula will be described in more detail. First, compound (1-2) is synthesized by reacting compound (1-1) as a nucleophile with chloromethyl methyl ether in the presence of a base. As the solvent for the reaction, in the embodiment of the present invention, one or more combinations of toluene, xylene, hexane, heptane, dichloromethane, chloroform, dichloroethane, diethyl ether, tetrahydrofuran, dibutyl ether, acetone, 2-butanone, ethyl acetate, butyl acetate, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and water can be selected; in addition, the reaction can also be carried out without a solvent. Furthermore, a phase transfer catalyst such as tetrabutylammonium hydrogen sulfate can also be added as a catalyst. As the base for the reaction, sodium amide, potassium amide, diisopropyl lithium amide, diisopropyl potassium amide, dicyclohexyl lithium amide, dicyclohexyl potassium amide, 2,2,6,6-tetramethylpiperidinium lithium, bis(trimethylsilyl) lithium amide, bis(trimethylsilyl) sodium amide, bis(trimethylsilyl) potassium amide, isopropylcyclohexyl lithium amide, diisopropylamine magnesium bromide (bromo magnesium the like; inorganic hydroxides such as sodium hydroxide, lithium hydroxide, potassium hydroxide, barium hydroxide, tetra-n-butylammonium hydroxide, etc.; inorganic carbonates such as sodium carbonate, sodium bicarbonate, lithium carbonate, potassium carbonate, etc.; metal hydrides such as sodium hydride, lithium hydride, potassium hydride, calcium hydride, etc.; alkyl metal compounds such as trityl lithium, trityl sodium, trityl potassium, methyl lithium, phenyl lithium, sec-butyl lithium, tert-butyl lithium, ethyl magnesium bromide, etc.; one or more combinations of ammonia, triethylamine, diisopropylethylamine, pyridine, lutidine, collidine, N,N-dimethylaniline. The amount of the base used is preferably 0.5 to 10 mol, particularly preferably 0.8 to 3.0 mol, relative to 1.0 mol of the nucleophile (1-1). If the amount used is 0.5 mol or more, the reaction can proceed sufficiently, and if the amount used is 10 mol or less, the side reaction can be suppressed, so there is no possibility of a decrease in yield and purity, and the cost can also be controlled. The amount of chloromethyl methyl ether used is preferably 0.1 to 10 mol, particularly preferably 0.5 to 2.0 mol, relative to 1.0 mol of the nucleophile (1-1). If the amount used is 0.1 mol or more, there is no possibility that the nucleophile (1-1) will remain excessively and become difficult to purify, and if the amount used is 10 mol or less, the side reaction can be suppressed, so there is no possibility of a decrease in yield and purity, and the cost can also be controlled. Furthermore, the carboxylic acid compound (1-2) is reacted with one or more of ethylene glycol or polyethylene glycol in the presence of a condensing agent to synthesize the compound (1-3). As the solvent for the reaction, in the embodiment of the present invention, one or more combinations of toluene, xylene, hexane, heptane, dichloromethane, chloroform, dichloroethane, diethyl ether, tetrahydrofuran, dibutyl ether, acetone, 2-butanone, ethyl acetate, butyl acetate, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and water can be selected. As the condensing agent used for the reaction, in the embodiment of the present invention, one or more combinations of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate can be selected. The amount of the condensing agent used is preferably 0.5 to 10 mol, particularly preferably 0.8 to 3.0 mol, relative to 1.0 mol of the carboxylic acid compound (1-2). If the amount used is 1.1 mol or more, the reaction can proceed sufficiently. If the amount used is 10 mol or less, the side reaction can be suppressed, so there is no possibility of a decrease in yield and purity, and the cost can also be controlled. The amount of ethylene glycol or polyethylene glycol used is preferably 0.1 to 10 mol, more preferably 0.5 to 2.0 mol, relative to 1.0 mol of the carboxylic acid compound (1-2). If the amount used is 1.2 mol or more, there is no possibility that the carboxylic acid compound (1-2) remains excessively and becomes difficult to purify, and if the amount used is 10 mol or less, the side reaction can be suppressed, so there is no possibility of a decrease in yield and purity, and the cost can also be controlled. Furthermore, compound (1-3) as a nucleophile is reacted with compound (1-4) in the presence of a base to synthesize compound (1-5). As the solvent for the reaction, one or more combinations of toluene, xylene, hexane, heptane, dichloromethane, chloroform, dichloroethane, diethyl ether, tetrahydrofuran, dibutyl ether, acetone, 2-butanone, ethyl acetate, butyl acetate, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and water can be selected in the embodiment of the present invention. In addition, the reaction can also be carried out without solvent. Further, a phase transfer catalyst such as tetrabutylammonium hydrogen sulfate can also be added as a catalyst. As the base for the reaction, sodium hydrogen, sodium amide, potassium amide, diisopropyl lithium amide, diisopropyl potassium amide, dicyclohexyl lithium amide, dicyclohexyl potassium amide, 2,2,6,6-tetramethylpiperidinium lithium, bis(trimethylsilyl) lithium amide, bis(trimethylsilyl) sodium amide, bis(trimethylsilyl) potassium amide, isopropylcyclohexyl lithium amide, diisopropyl magnesium bromide (bromo magnesium the like; metalamides such as trityl lithium, trityl sodium, trityl potassium, methyl lithium, phenyl lithium, sec-butyl lithium, tert-butyl lithium, ethyl magnesium bromide, etc.; one or more combinations of amines such as ammonia, triethylamine, diisopropylethylamine, pyridine, lutidine, colloidal pyridine, N, N-dimethylaniline, etc. The amount of the base used is preferably 0.5 to 10 mol, more preferably 0.8 to 3.0 mol, relative to 1.0 mol of the nucleophile (1-3). If the amount used is 0.5 mol or more, the reaction can proceed sufficiently. If the amount used is 10 mol or less, the side reaction can be suppressed. Therefore, there is no possibility of a decrease in yield and purity, and the cost can also be controlled. The amount of compound (l-4) used is preferably 0.1 to 10 mol, more preferably 0.5 to 2.0 mol, relative to 1.0 mol of the nucleophile (l-3). If the amount used is 0.1 mol or more, there is no possibility that the nucleophile (l-3) will remain excessively and become difficult to purify, and if the amount used is 10 mol or less, the side reaction can be suppressed, so there is no possibility of a decrease in yield and purity, and the cost can also be controlled. Furthermore, the fluoroalkyl compound (1-5) is sulfinated in the presence of sodium dithionite to give the compound (1-6). As the solvent for the reaction, in the embodiment of the present invention, one or more combinations of toluene, xylene, hexane, heptane, dichloromethane, chloroform, dichloroethane, diethyl ether, tetrahydrofuran, dibutyl ether, acetone, 2-butanone, ethyl acetate, butyl acetate, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and water can be selected. Furthermore, the sodium sulfinate compound (1-6) is reacted with an oxidizing agent in the presence of a catalyst to synthesize a compound (1-7). As the solvent for the reaction, one or more combinations of toluene, xylene, hexane, heptane, dichloromethane, chloroform, dichloroethane, diethyl ether, tetrahydrofuran, dibutyl ether, acetone, 2-butanone, ethyl acetate, butyl acetate, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and water can be selected in the embodiment of the present invention. In addition, the reaction can also be carried out without solvent. Further, a phase transfer catalyst such as tetrabutylammonium hydrogen sulfate can also be added as a catalyst. As the catalyst for the reaction, in the embodiment of the present invention, one or more combinations of palladium acetate, palladium chlorides, nickel chloride, nickel sulfate, nickel acetate, nickel acetylacetonate, and sodium tungstate can be selected. The amount of the catalyst used is preferably 0.01 to 1 mol, more preferably 0.02 to 0.5 mol, relative to 1.0 mol of the sodium sulfinate compound (1-6). If the amount used is 0.02 mol or more, the reaction can be fully carried out. If the amount used is 0.5 mol or less, the side reaction can be suppressed, so there is no possibility of a decrease in yield and purity, and the cost can also be controlled. The amount of the oxidant used is preferably 0.1 to 10 mol, more preferably 0.5 to 5.0 mol, relative to 1.0 mol of the sodium sulfinate compound (1-6). If the amount used is 1.2 mol or more, there is no possibility that the sodium sulfinate compound (1-6) remains excessively and becomes difficult to purify, and if the amount used is 10 mol or less, the side reaction can be suppressed, so there is no possibility of a decrease in yield and purity, and the cost can also be controlled. Furthermore, the ether compound (1-7) is subjected to deprotection in the presence of an acid to synthesize a compound (1-8). As the solvent for the reaction, in the embodiment of the present invention, one or more combinations of toluene, xylene, hexane, heptane, dichloromethane, chloroform, dichloroethane, diethyl ether, tetrahydrofuran, dibutyl ether, acetone, 2-butanone, ethyl acetate, butyl acetate, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and water can be selected. In addition, the reaction can also be carried out without a solvent. As the acid used for the reaction, in the embodiment of the present invention, one or more combinations of sulfuric acid, hydrochloric acid, methanesulfonic acid, trifluoromethanesulfonic acid, and p-toluenesulfonic acid can be selected. The amount of acid used is preferably 0.1 to 10 mol, more preferably 0.3 to 3.0 mol, relative to 1.0 mol of the ether compound (1-7). If the amount used is 0.2 mol or more, the reaction can proceed sufficiently. If the amount used is 10 mol or less, the side reaction can be suppressed. Therefore, there is no possibility of a decrease in yield and purity, and the cost can also be controlled. Furthermore, compound (1-8) as a nucleophile is reacted with compound (1-9) in the presence of a base to synthesize compound (1-10). As the solvent for the reaction, in the embodiment of the present invention, one or more combinations of toluene, xylene, hexane, heptane, dichloromethane, chloroform, dichloroethane, diethyl ether, tetrahydrofuran, dibutyl ether, acetone, 2-butanone, ethyl acetate, butyl acetate, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and water can be selected. In addition, the reaction can also be carried out without a solvent. As the base for the reaction, sodium amide, potassium amide, diisopropyl lithium amide, diisopropyl potassium amide, dicyclohexyl lithium amide, dicyclohexyl potassium amide, 2,2,6,6-tetramethylpiperidinium lithium, bis(trimethylsilyl) lithium amide, bis(trimethylsilyl) sodium amide, bis(trimethylsilyl) potassium amide, isopropylcyclohexyl lithium amide, diisopropylamine magnesium bromide (bromo magnesium the like; inorganic hydroxides such as sodium hydroxide, lithium hydroxide, potassium hydroxide, barium hydroxide, tetra-n-butylammonium hydroxide, etc.; inorganic carbonates such as sodium carbonate, sodium bicarbonate, lithium carbonate, potassium carbonate, etc.; metal hydrides such as sodium hydride, lithium hydride, potassium hydride, calcium hydride, etc.; alkyl metal compounds such as trityl lithium, trityl sodium, trityl potassium, methyl lithium, phenyl lithium, sec-butyl lithium, tert-butyl lithium, ethyl magnesium bromide, etc.; one or more combinations of ammonia, triethylamine, diisopropylethylamine, pyridine, lutidine, collidine, N,N-dimethylaniline. The amount of the base used is preferably 0.5 to 10 mol, more preferably 0.8 to 3.0 mol, relative to 1.0 mol of the nucleophile (1-9). If the amount used is 0.5 mol or more, the reaction can proceed sufficiently. If the amount used is 10 mol or less, the side reaction can be suppressed. Therefore, there is no possibility of a decrease in yield and purity, and the cost can also be controlled. The amount of compound (1-9) used is preferably 0.1 to 10 mol, more preferably 0.5 to 2.0 mol, relative to 1.0 mol of the nucleophile (1-8). If the amount used is 0.1 mol or more, there is no possibility that the nucleophile (1-8) will remain excessively and become difficult to purify. If the amount used is 10 mol or less, the side reaction can be suppressed, so there is no possibility of a decrease in yield and purity, and the cost can also be controlled. Furthermore, by subjecting the sulfonate (1-10) to ion exchange with a salt having a desired cation, the target photoacid generator (1-11) can be synthesized. The ion exchange can be easily performed using a known method. The reaction temperature in each of the above steps is preferably about -70°C to the boiling point of the solvent used. The appropriate reaction temperature is selected according to the reaction conditions, but it is usually preferably about 0°C to the boiling point of the solvent used. Since there is a situation where the side reaction becomes significant if the reaction temperature increases, it is important to react at a temperature as low as possible within the range of a practical speed to achieve a high yield. In order to improve the yield, the reaction time of the above reaction is preferably determined by tracking the progress of the reaction by thin layer chromatography, gas chromatography, ion chromatography, liquid chromatography, etc., and is usually 0.5h to 40h. The target compound can be obtained from the reaction mixture by conventional aqueous work-up, and when necessary, it can be purified by conventional methods such as recrystallization and chromatography. The main resin involved in the embodiment of the present invention has a structure as shown in general formula (3): In the general formula (3) of the embodiment of the present invention, R6 represents one of a hydrogen atom, a fluorine atom, a methyl group and a trifluoromethyl group; R7 represents a hydrogen atom, or a polar group having a structure comprising one or more of a branched chain, a hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a carbonate bond, a lactone ring, and a carboxylic anhydride. Preferably, in the embodiment of the present invention, R7 comprises one or more combinations of the following groups: Particularly preferably, in the embodiment of the present invention, R7 comprises one or more combinations of the following groups: In the embodiment of the present invention, the resist composition further comprises one or more of the following components: an acid diffusion inhibitor, an additive, and a fluorine-containing resin. The embodiment of the present invention also includes an acid diffusion inhibitor. By adding the acid diffusion inhibitor to the resist composition, the contrast between the exposed part and the non-exposed part when forming the resist pattern can be improved. The acid diffusion inhibitor is not particularly limited as long as it can be decomposed by exposure and lose the acid diffusion controllability. Conventional acid diffusion inhibitors in the art can be selected. As examples of acid diffusion inhibitors, compounds with the following structures are included: Preferably, the acid diffusion inhibitor of the embodiment of the present invention can be selected from compounds with the following structures: The acid diffusion inhibitor loses its acid diffusion control property (basicity) due to decomposition, and therefore does not have a quenching effect in the exposed portion of the resist film, but functions as a quencher in the unexposed portion. In order to impart water resistance to the resist film, the present invention includes a fluororesin in an embodiment, which is a polymer having a structural unit as shown in the general formula (4): In the general formula (4), R8 and R9 represent hydrogen atoms, halogen atoms, alkane groups with 1 to 5 carbon atoms, or halogenated alkane groups with 1 to 5 carbon atoms, and R8 and R9 are the same or different; 10 It is an organic group containing fluorine atoms; R 11 is a hydrogen atom or a methyl group; The fluorine-containing resin in the embodiment of the present invention comprises the following compounds: The number average molecular weight (Mw) of the fluorine-containing resin in the present invention (measured by gel permeation chromatography in terms of polystyrene) is preferably 1000 to 50000, more preferably 5000 to 40000, and particularly preferably 10000 to 30000. If it is below the upper limit of the range, the solubility in the resist solvent used as the resist is sufficient, and if it is above the lower limit of the range, the dry etching resistance and the cross-sectional shape of the resist pattern are good; the dispersion degree (Mw / Mn) of the fluorine-containing resin in the embodiment of the present invention is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and particularly preferably 1.2 to 2.5. In the embodiment of the present invention, the purpose is to prevent sensitivity degradation and improve the shape of the resist pattern, storage stability over time, etc. In the embodiment of the present invention, an additive is included, wherein the additive is one or more combinations of organic carboxylic acids or oxygen-containing phosphoric acids and their derivatives; Preferably, the additive in the embodiment of the present invention comprises one or more combinations of acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid, phosphoric acid, phosphonic acid, and phosphinic acid. Particularly preferably, the additive in the embodiment of the present invention comprises salicylic acid. In the embodiment of the present invention, the resist composition can be prepared by dissolving the resist material in an organic solvent. As examples of the organic solvent, the embodiment of the present invention includes lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl n-amyl ketone, methyl isoamyl ketone, 2-heptanone; diols; compounds having ester bonds such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate or dipropylene glycol monoacetate; monomethyl ethers and monoethyl ethers of the above polyols or compounds having ester bonds; derivatives of polyols, such as compounds having ether bonds, such as ether, monopropyl ether and monobutyl ether. Ethers and other monoalkyl ethers or monophenyl ethers, such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME); dioxane, methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl ether and other cyclic ether acetates, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl propionate and other ethoxy esters; anisole, ethyl benzyl ether, methyltolyl methyl ether, diphenyl ether, dibenzyl ether, phenylethyl ether, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, methyl isopropylbenzene, mesitylene or one or more combinations thereof. Preferably, the solvent in the embodiment of the present invention is preferably one or a combination of propylene glycol monomethyl ether acetate PGMEA and γ-butyrolactone GBL. The present invention also provides a pattern forming method including the steps of coating a resist composition on a substrate; exposing the substrate through a photomask using any one of high-energy rays, electron beams or extreme ultraviolet light with a wavelength of 140 to 250 nm after a heat treatment before exposure; and developing the substrate using a developer after the exposure and heat treatment; using an alkaline aqueous solution or an organic solvent as a developer to dissolve the exposed or unexposed portion, thereby obtaining a positive or negative pattern. As for the developer involved in the embodiment of the present invention, TMAH can be listed as the developer of alkaline aqueous solution; as the developer of organic solvent development, 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate ... The invention can be one or more combinations of methyl pentanoate, methyl crotonate, ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate and 2-phenylethyl acetate. According to the pattern forming method of the present invention, by using the resist composition containing the photoacid generator of the present invention, a fine pattern with few defects and excellent rectangularity can be formed. Example Photoacid generator: Synthesis example 1-1 Synthesis of PAG-1 Synthesis of intermediate (1-1-2) At room temperature, 30g 3-hydroxyadamantane-1-carboxylic acid, 39.52g N,N-diisopropylethylamine, 150g dichloromethane were stirred and dissolved. Then 18.46g chloromethoxymethane was slowly added dropwise, and the reaction was stirred for 24 hours at 60°C. After the reaction was completed, the reaction solution was returned to room temperature, and then the reaction solution was poured into a 10wt% sodium hydroxide solution and stirred at room temperature for 1 hour. After that, it was allowed to stand, separated, and the lower organic phase was taken. The organic phase was washed twice with ultrapure water, then spin-dried and dried to obtain a crude product (1-1-2). Synthesis of intermediate (1-1-3) Under an ice bath, add the above-synthesized intermediate (1-1-2), 18.97g ethylene glycol, 1.87g 4-(dimethylamino)pyridine, and 300g dichloromethane. Stir and dissolve, then reduce the temperature of the reaction system to 0-5°C, slowly add 43.9g 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, after the addition is completed, stir for 24 hours, then gradually warm to room temperature. After the reaction is completed, concentrate the reaction solution under reduced pressure, add 200g ethyl acetate and 100mL 1mol / L hydrochloric acid to the remaining residue, extract, separate, and collect the organic phase. The organic phase is washed with saturated sodium bicarbonate solution and brine, then spin-dried, and dried to obtain the intermediate (1-1-3). Synthesis of intermediate (1-1-4) Under an ice bath, add the above-synthesized intermediate (1-1-3) and 200g tetrahydrofuran, stir to dissolve, then lower the temperature of the reaction system to 0-5°C, slowly add 7.34g sodium hydrogen in batches, and stir for 6 hours after the addition is complete. Then slowly add a tetrahydrofuran (150g) solution of 4-bromo-3,3,4,4-tetrafluoro-1-butanol (37.82g), and stir for 6 hours after the addition is complete. After the reaction is completed, filter to remove insoluble matter, then slowly pour the reaction solution into 1mol / L hydrochloric acid, then add ether for extraction, separate the liquids, and collect the organic phase. The organic phase is washed with a saturated sodium bicarbonate solution and brine, then spin-dried, and dried to obtain a crude product. Use 200-300 mesh silica gel column chromatography to obtain 39g of the target compound (1-1-4). Synthesis of intermediate (1-1-5) At room temperature, add the above intermediate (1-1-4) 30g, 120g acetonitrile, stir to dissolve, then add 10.26g sodium bicarbonate, 21.26g 85wt% sodium dithionite and 80g water, stir and react at 55°C for 4 hours. After the reaction is completed, cool to room temperature, then stand, separate, and take the upper organic phase. The organic phase is spin-dried and dried to obtain the intermediate (1-1-5). Synthesis of intermediate (1-1-6) At room temperature, add the intermediate (1-1-5) synthesized above, 0.9g sodium tungstate and 150g water, stir and dissolve. Then slowly add 13.85g 30wt% hydrogen peroxide solution. After the addition is completed, stir for 3 hours. After the reaction is completed, concentrate the reaction solution and then rinse with diisopropyl ether. Then filter and dry to obtain the intermediate (1-1-6). Synthesis of intermediate (1-1-7) At room temperature, add the intermediate (1-1-6) synthesized above and 200g of dichloromethane, stir and dissolve. Then lower the temperature of the reaction system to 0-5°C, slowly add 0.5mL of 4mol / L sulfuric acid, and stir for 1 hour after the addition is complete. After the reaction is complete, wash the reaction solution with ultrapure water, let it stand, separate the liquids, and collect the lower organic phase. The organic phase is spin-dried and dried to obtain the intermediate (1-1-7). Synthesis of intermediate (1-1-8) At room temperature, add the intermediate (1-1-7) synthesized above, 13.8g tert-butyl chloroacetate, and 300g dichloromethane, stir to dissolve, then add 100mL 1mol / L sodium hydroxide aqueous solution, and stir at room temperature for 1 hour. Let stand, separate the liquid, take the lower organic phase, and wash the organic phase with ultrapure water 5 times. The organic phase is spin-dried and dried to obtain the intermediate (1-1-8). Synthesis of PAG-1 At room temperature, the intermediate (1-1-8) synthesized above and water were stirred and dissolved. Subsequently, an aqueous solution of triphenylsulfonium chloride (21.93 g) was added at room temperature. Then, the mixture was stirred at room temperature for 2 hours. After the reaction was completed, the solid matter was filtered and dried to obtain 27.2 g of the target product PAG-1. The synthesis of PAG-2 to 5 is similar to that of PAG-1, wherein in PAG-2, the triphenylsulfonium chloride in PAG-1 prepared by reacting the intermediate 1-1-9 is replaced with 4-hydroxymethylphenyl-diphenylsulfonium chloride (24.14 g), and the other steps are the same as those of PAG-1; in the preparation of PAG-3, diethylene glycol (32.43 g) is selected to replace the ethylene glycol used in the synthesis process of the intermediate 1-1-3, and the other steps are the same as those of PAG-1; in the preparation of PAG-4, triethylene glycol (45.89 g) is selected to replace the ethylene glycol used in the synthesis process of the intermediate 1-1-3, and the other steps are the same as those of PAG-1; in the preparation of PAG-5, trifluoroethanol (9.2 g) is selected to replace tert-butyl chloroacetate used in the synthesis process of the intermediate 1-1-8, and the other steps are the same as those of PAG-1; Photoacid generators other than the PAGs mentioned in the above synthesis examples: PAG-6 (Japanese patent: JP6986880B2) PAG-7 (Japanese patent: JP5978139B2) Main resin Synthesis example 2-1 Synthesis of main resin S1 Under a nitrogen atmosphere, 8.5 g of the monomer corresponding to the structural unit shown in A2-1-1, 13.81 g of the monomer corresponding to the structural unit shown in A2-1-2, 0.48 g of AIBN, 0.41 g of 2-mercaptoethanol and 50 g of methyl ethyl ketone were taken to prepare a monomer-polymerization initiator solution. 23 g of methyl ethyl ketone was added to another flask set to a nitrogen atmosphere, and after heating to 80 ° C while stirring, the above-mentioned monomer-polymerization initiator solution was added dropwise for 4 hours. After the addition was completed, the temperature of the polymerization solution was maintained at 80 ° C and continued to stir for 2 hours, and then cooled to room temperature. The obtained polymerization solution was added dropwise to 640 g of vigorously stirred methanol, and the precipitated copolymer was filtered. After washing the copolymer twice with 240 g of methanol, it was vacuum dried at 50 ° C for 20 hours to obtain 20.5 g of white powder copolymer. The result of analysis by GPC showed that the weight average molecular weight (Mw) converted to polystyrene was 8,400 and the dispersion was 1.66. Synthesis Examples 2-2 to 2-5 Synthesis of Main Resins S2 to S4 and SD5 Except for changing the type and addition ratio of each monomer, the main resin was prepared in the same order as in Synthesis Example 2-1. The compositions of the prepared main resins S2~S4 and SD5 are shown in Table 1. In addition, the introduction ratio in Table 1 represents the molar ratio. In addition, the structural units in Table 1 are shown in Table 2. Table 1 Table 2 Acid Diffusion Inhibitors D-1 is an acid diffusion inhibitor as shown below (Japanese Patent Publication: JP7033849B2) Fluorine-containing resin F-1 is a fluorine-containing resin as shown below (Japanese Patent Publication: JP6093614B2) additive T-1: Salicylic acid. Solvents R-1: GBL: gamma-butyrolactone; R-2: PGMEA: Propylene glycol monomethyl ether acetic acid. In the preparation of the resist composition solutions of Examples 1 to 7 and Comparative Examples 1 to 3, the above-mentioned main resin, photoacid generator, acid diffusion inhibitor, fluorine-containing resin, additive and solvent are configured into a resist composition. The composition of each prepared resist composition solution is shown in Table 3 below: Table 3 Serial number Main resin Photoacid generator Acid Diffusion Inhibitors Fluorine-containing resin additive Solvents Example 1 S1(100) PAG-1(5.5) D-1(3.0) F-1(2.0) T-1(0.15) R-1(125)+R-2(3000) Example 2 S3(100) PAG-2(5.3) D-1(3.0) F-1(2.0) T-1(0.15) R-1(155)+R-2(3050) Example 3 S4(100) PAG-3(5.4) D-1(3.0) F-1(2.0) T-1(0.15) R-1(125)+R-2(3000) Example 4 S2(100) PAG-4(5.5) D-1(3.1) F-1(2.0) T-1(0.15) R-1(125)+R-2(3000) Example 5 S1(100) PAG-5(5.6) D-1(3.0) F-1(2.0) T-1(0.15) R-1(100)+R-2(3200) Example 6 S2(100) PAG-1(4.5)+PAG-5(1.0) D-1(3.0) F-1(2.0) T-1(0.15) R-1(100)+R-2(3200) Example 7 S4(100) PAG-2(3.5)+PAG-3(2.1) D-1(3.0) F-1(2.0) T-1(0.15) R-1(125)+R-2(3000) Comparative Example 1 S1(100) PAG-6(5.5) D-1(2.9) F-1(2.0) T-1(0.15) R-1(100)+R-2(3200) Comparative Example 2 S3(100) PAG-7(5.5) D-1(3.0) F-1(2.0) T-1(0.15) R-1(125)+R-2(3000) Comparative Example 3 SD5(100) PAG-1(5.3) D-1(3.0) F-1(2.0) T-1(0.15) R-1(100)+R-2(3200) ArF-i exposure patterning evaluation Line width / space evaluation On a substrate for a three-layer process, a spin-coated carbon film ODL-101 manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a film thickness of 200 nm, and a silicon-containing spin-coated hard mask SHB-A940 (silicon content of 43 mass %) was formed with a film thickness of 35 nm. The resist compositions of Examples 1 to 7 of the present invention and the resist compositions of Comparative Examples 1 to 3 prepared with the compositions shown in Table 3 were spin-coated, and baked at 100° C. for 60 seconds using a hot plate to form a resist film with a thickness of 100 nm. The resist film was pattern-exposed using an ArF immersion excimer laser scanner (manufactured by Nikon Corporation, NSR-610C. NA = 1.30, σ 0.98 / 0.78, 4 / 5 annular illumination) with a 6% halftone phase shift mask having a pitch of 100 nm and a pitch of 50 nm arranged on a wafer, and a heat treatment (PEB) was performed for 60 seconds after exposure, and a 2.38% tetramethylammonium hydroxide (TMAH) aqueous solution was ejected from a developing nozzle while rotating at 30 rpm for 3 seconds, and then a static puddle (spin-over immersion) development was performed for 27 seconds. As a result, the exposed portion was dissolved in the developer, and a line width / pitch pattern (hereinafter referred to as LS pattern) having a pitch of 50 nm and a pitch of 100 nm was obtained. Sensitivity evaluation The obtained LS pattern was observed with an electron microscope, and the optimum exposure amount Eop (mJ / cm) for obtaining an LS pattern with a pitch of 50 nm and a pitch of 100 nm was determined. Exposure Latitude (EL) Evaluation As an evaluation of the exposure latitude, the exposure latitude (unit: %) was determined by the following formula from the exposure amount formed within the range of 50 nm pitch ±10% (45 nm to 55 nm) in the obtained LS pattern. Exposure latitude (%) = (|E1-E2| / Eop) × 100 El: Optimal exposure for forming LS patterns with a pitch of 45 nm and a pitch of 100 nm E2: Optimal exposure for forming LS pattern with a pitch of 55 nm and a pitch of 100 nm Eop: Optimal exposure for forming LS patterns with a pitch of 50nm and a pitch of 100nm Mask Error Factor (MEF) Evaluation The line width of the mask is changed while the pitch of the mask is fixed, and the pattern is formed by irradiation with the optimal exposure in the above sensitivity evaluation. The value of MEF is calculated by the following formula from the change of the line width of the mask and the pitch of the pattern. The closer the value is to 1, the better the performance. MEF = (pattern pitch / mask line width) - b b: constant Line Width Roughness (LWR) Evaluation

[0650] Using TDSEM (S-9380) manufactured by Hitachi High-Technologies Corporation, the LS pattern obtained by irradiation at the optimal exposure amount was measured at 10 locations in the long side direction of the pitch, and the value (3σ) tripled by the standard deviation (σ) was calculated from the result and used as LWR. The smaller this value is, the smaller the roughness and the more uniform the pitch can be obtained. Defect density evaluation The number of defects in the pattern formed after development was inspected by a defect inspection apparatus KLA2800 (manufactured by KLA-Tencor Corporation), and the defect density was calculated according to the following formula. Defect density (pcs / cm2) = total number of defects detected / inspection area; Pattern formed: Repeating pattern of 1:1 line width / spacing of 50nm; Defect inspection conditions: light source UV, inspection pixel size 0.28um, inter-cell mode. The evaluation results are shown in Table 4: Table 4 Serial number PEB(℃) <![CDATA[Defect density (pcs / cm 2 )]]> Eop(mJ / cm2) EL(%) MEF LWR(nm) Example 1 93 0.011 27 15.6 3 3.3 Example 2 93 0.043 33 14.7 3.8 3.5 Example 3 93 0.021 29 15.8 3 3.1 Example 4 93 0.05 31 14.6 3.7 3.7 Example 5 95 0.045 33 14.4 3.9 3.6 Example 6 93 0.038 28 14.9 3.6 3.6 Example 7 95 0.046 29 14.8 3.7 3.8 Comparative Example 1 93 0.082 31 10.5 4.2 5.1 Comparative Example 2 93 0.069 32 11.1 4.5 4.8 Comparative Example 3 90 0.094 34 10.9 4.1 4.4 It should be noted that, according to the explanation and elaboration of the above description, those skilled in the art to which the present invention belongs may also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some equivalent modifications and changes to the present invention should also be within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the invention.

Claims

1. A resist composition, characterized in that It comprises a main resin, a photoacid generator and an organic solvent; the photoacid generator has an anion and a cation, and the anion has a structure as shown in the general formula (1): In the general formula (1), R f Said R4 represents one or more combinations of alkyl groups with carbon atoms of 1 to 4 and fluoroalkyl groups; said R4 represents one or more combinations of monovalent straight-chain hydrocarbon groups with carbon atoms of 1 to 20 which may contain heteroatoms, branched hydrocarbon groups, and cyclic hydrocarbon groups, and / or said R4 comprises one or more combinations of amide bonds, ether bonds, and ester bonds; said R5 represents one or more combinations of monovalent cyclic hydrocarbon groups with carbon atoms of 4 to 8 or adamantyl groups; said n is an integer between 0 and 5.

2. The resist composition according to claim 1, characterized in that The cation in the photoacid generator has a structure as shown in general formula (2): In the general formula (2), R1, R2, and R3 represent a monovalent straight-chain hydrocarbon group with 1 to 20 carbon atoms, which may contain hydrogen atoms or heteroatoms, or a combination of one or more of a branched hydrocarbon group and a cyclic hydrocarbon group.

3. The resist composition according to claim 1, characterized in that The main resin has a structure as shown in general formula (3): In the general formula (3), R6 represents one of a hydrogen atom, a fluorine atom, a methyl group and a trifluoromethyl group; R7 represents a hydrogen atom, or a polar group having a structure including one or more of a branched chain, a hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a carbonate bond, a lactone ring, and a carboxylic anhydride.

4. The resist composition according to claim 1, characterized in that The resist composition further comprises one or more selected from the following components: an acid diffusion inhibitor, an additive, and a fluorine-containing resin.

5. The resist composition according to claim 1 or 2, characterized in that The photoacid generator comprises one of the structures shown below: Preferably, the photoacid generator comprises one of the structures shown below:

6. The resist composition according to claim 3, characterized in that In the general formula (3) of the main resin, R7 represents one or more combinations of the following groups: Preferably, R7 represents one or more combinations of the following groups:

7. The resist composition according to claim 4, wherein the acid diffusion inhibitor is one or more of the following compounds: and / or and / or 8. The resist composition according to claim 4, wherein the fluorine-containing resin comprises a polymer having a structural unit represented by the general formula (4): In the general formula (4), R8 and R9 represent hydrogen atoms, halogen atoms, alkane groups with 1 to 5 carbon atoms, or halogenated alkane groups with 1 to 5 carbon atoms, and R8 and R9 are the same or different; 10 It is an organic group containing fluorine atoms; R 11 is a hydrogen atom or a methyl group; Preferably, the fluorine-containing resin comprises the following compounds:

9. The resist composition according to claim 4, wherein the additive is one or more combinations of organic carboxylic acids or oxygen-containing phosphoric acids and their derivatives; Preferably, the additive comprises one or more combinations of acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid, phosphoric acid, phosphonic acid, and phosphinic acid.

10. A pattern forming method, characterized in that: The pattern forming method comprises the steps of coating the resist composition described in any one of claims 1 to 9 on a substrate; exposing the substrate through a photomask using any one of high-energy rays, electron beams or extreme ultraviolet light with a wavelength of 140 to 250 nm after a heat treatment before exposure; and developing the substrate using a developer after the exposure and heat treatment; using an alkaline aqueous solution or an organic solvent as a developer to dissolve the exposed or unexposed part, thereby obtaining a positive or negative pattern.

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