Salt compound, acid diffusion inhibitor containing same, and photoresist composition

Abstract

The present invention relates to a salt compound containing an anion having a specific structure represented by Chemical Formula 1 and a cation represented by Chemical Formula 2, and an acid diffusion inhibitor and photoresist composition containing the same.

Description

[Technical field]

[0001] The present invention relates to a salt compound, an acid diffusion inhibitor (quencher) containing the same, and a photoresist composition. More specifically, the present invention relates to a novel photosensitive salt compound used in a chemically amplified resist material, and an acid diffusion inhibitor (quencher) and a photoresist composition containing the same. [Background technology]

[0002] Lithography is a technology in which a resist material made of a photosensitive material is applied onto a substrate to form a resist film, and then a mask having a pattern formed thereon is used to perform exposure and development processes using a selected light source to transfer the mask pattern onto the resist film to form a pattern.

[0003] Semiconductor devices manufactured using lithography technology use a short wavelength light source to manufacture finer patterns on semiconductor elements. For example, in the past, near ultraviolet light (g-line (436 nm), i-line (365 nm)) was used, but now deep ultraviolet light (KrF (248 nm), ArF (193 nm) excimer lasers are used, and ArF immersion and the multi-patterning method using this are widely used in the mass production of semiconductor elements. Recently, even lithography technology using extreme ultraviolet (EUV (13.5 nm)) wavelengths has begun to be introduced into the mass production process.

[0004] Resist materials are required to have characteristics such as sensitivity to an exposure light source and resolution capable of reproducing fine mask patterns. Resist components that can exhibit such characteristics include a chemically amplified photoresist (CAR) composition that contains a photoacid generator that generates acid during the exposure process, a polymer resin whose solubility in an alkaline developer changes due to the action of the generated acid, an acid diffusion inhibitor that can adjust the acid diffusion distance, and a solvent that can dissolve each component.

[0005] In the field of conventional chemically amplified resist compositions, nitrogen-containing organic substances such as amines and amides capable of controlling the diffusion distance of an acid generated from a photoacid generator have been used to improve resist performance.

[0006] However, recently, instead of nitrogen-containing organic compounds, photodegradable acid diffusion inhibitors that have a structure similar to that of photoacid generators and are decomposed by an exposure source have been developed. These photodegradable base acid diffusion inhibitors act as quenchers that suppress acid diffusion in non-exposed areas, and act as acids by being photodecomposed in exposed areas, thereby maintaining a relatively high acid concentration in exposed areas and increasing the acid distribution contrast between exposed and non-exposed areas, thereby improving lithography characteristics.

[0007] However, the formation of a pattern of a desired size from a resist material has not yet reached an ideal level. From this perspective, there remains a need to develop a photosensitive acid diffusion inhibitor having a new structure in order to ensure high contrast during the formation of a fine pattern. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention provides a salt compound that can provide a photoresist composition having improved polarity, which shortens the diffusion length of anions generated upon exposure, ensures high contrast, improves the limiting resolution, and has low sensitivity, LER value, and a high process margin. The present invention also provides an acid diffusion inhibitor containing the salt compound. The present invention further provides a photoresist composition comprising the salt compound. [Means for solving the problem]

[0009] Provided herein is a salt compound comprising an anion represented by Chemical Formula 1 below, and a cation represented by Chemical Formula 2 below: [Chemical formula 1] JPEG2025500244000001.jpg35170[Chemical formula 2] JPEG2025500244000002.jpg16170

[0010] The present specification also provides an acid diffusion inhibitor comprising the salt compound. Further provided herein is a photoresist composition comprising the salt compound. The present specification also provides a method for forming a photoresist pattern using the photoresist composition.

[0011] Hereinafter, the salt compound and the acid diffusion inhibitor containing the same, the photoresist composition, and the method for forming a photoresist pattern according to specific embodiments of the present invention will be described in more detail.

[0012] In this specification, when a part "comprises" a certain component, this means that it can further include other components, not excluding other components, unless otherwise specified.

[0013] In this specification, the term polymer is used interchangeably with the terms macromolecule and polymeric substance.

[0014] In this specification, examples of the substituents are described below, but the present invention is not limited thereto.

[0015] In this specification, the term "substituted" means that another atom or functional group is bonded in place of a hydrogen atom or a carbon atom in a compound, and the position of the substitution is not limited as long as it is a position of a hydrogen atom or a carbon atom, that is, a position that can be substituted by a substituent, and when two or more substitutions are performed, the two or more substituents may be the same or different from each other.

[0016] In this specification, the term "substituted or unsubstituted" means that the group is substituted or unsubstituted with one or more substituents selected from the group consisting of deuterium, halogen, cyano group, nitro group, hydroxyl group, carbonyl group, ester group, imide group, amide group, amino group, carboxyl group, sulfonic acid group, sulfonamide group, phosphine oxide group, alkoxy group, alkylcarbonyl group, alkoxycarbonyl group, sulfonyloxy group, aryloxy group, alkylthiooxy group, arylthiooxy group, alkylsulfoxy group, arylsulfoxy group, silyl group, and boron group, or that the group is substituted or unsubstituted with two or more of the above-mentioned examples of the substituents linked together. For example, the "substituent with two or more substituents linked together" may be a biphenyl group. In other words, the biphenyl group may be an aryl group, and may be interpreted as a substituent with two phenyl groups linked together.

[0017] In this specification, JPEG2025500244000003.jpg10170, or JPEG2025500244000004.jpg7170 refers to a bond that is connected to another substituent.

[0018] In this specification, examples of halogen include fluorine, chlorine, bromine or iodine.

[0019] In this specification, the number of carbon atoms of the imido group is not particularly limited, and may be 1 to 30. Specifically, the imido group may have a compound having the following structure, but is not limited thereto. [ka]

[0020] In this specification, the nitrogen of the amide group may be substituted with hydrogen, a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, or an aryl group having 6 to 30 carbon atoms. Specifically, the amide group may be a compound having the following structural formula, but is not limited thereto. [ka]

[0021] In this specification, the number of carbon atoms in the carbonyl group is not particularly limited, and may be 1 to 30. Specifically, the carbonyl group may have a compound having the following structure, but is not limited thereto. [ka]

[0022] In this specification, the oxygen of the ester group may be substituted with a linear, branched, or cyclic alkyl group having 1 to 25 carbon atoms, or an aryl group having 6 to 25 carbon atoms. Specifically, the ester group may be a compound having the following structural formula, but is not limited thereto. [ka]

[0023] In this specification, the sulfonamide group may be -SO2NR'R'', wherein R' and R'' are the same or different and are each independently selected from the group consisting of hydrogen; deuterium; halogen; nitrile group; substituted or unsubstituted monocyclic or polycyclic cycloalkyl group having 3 to 30 carbon atoms; substituted or unsubstituted linear or branched alkyl group having 1 to 30 carbon atoms; substituted or unsubstituted monocyclic or polycyclic aryl group having 6 to 30 carbon atoms; and substituted or unsubstituted monocyclic or polycyclic heteroaryl group having 2 to 30 carbon atoms.

[0024] In this specification, the alkyl group may be linear or branched, and the number of carbon atoms of the linear alkyl group is not particularly limited, but may be 1 to 20. Also, the number of carbon atoms of the branched alkyl group is 3 to 20. Exemplary alkyl groups include, but are not limited to, methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, 1-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 2-methylpentyl, 4-methylhexyl, 5-methylhexyl, and the like. The alkyl group may be substituted or unsubstituted, and when substituted, examples of the substituents are as described above.

[0025] In the present specification, the cycloalkyl group is not particularly limited, but may have 3 to 60 carbon atoms, and according to one embodiment, the cycloalkyl group has 3 to 30 carbon atoms. According to another embodiment, the cycloalkyl group has 3 to 20 carbon atoms. According to another embodiment, the cycloalkyl group has 3 to 6 carbon atoms. Specific examples include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3,4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, and cyclooctyl. The cycloalkyl group may be substituted or unsubstituted, and if substituted, examples of the substituent are as described above.

[0026] In this specification, the alkoxy group is a functional group in which the above-mentioned alkyl group is bonded to one end of an ether group (-O-), and the above-mentioned explanation of the alkyl group is applicable except that the alkoxy group is a functional group bonded to an ether group (-O-). For example, the alkoxy group may be linear, branched, or cyclic. The number of carbon atoms of the alkoxy group is not particularly limited, and may be 1 to 20 carbon atoms. Specific examples include, but are not limited to, methoxy, ethoxy, n-propoxy, isopropoxy, i-propyloxy, n-butoxy, isobutoxy, tert-butoxy, sec-butoxy, n-pentyloxy, neopentyloxy, isopentyloxy, n-hexyloxy, 3,3-dimethylbutyloxy, 2-ethylbutyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, cycloheptoxy, benzyloxy, and p-methylbenzyloxy. The alkoxy group may be substituted or unsubstituted, and when substituted, examples of the substituent are as described above.

[0027] In this specification, the amine group can be selected from the group consisting of -NH2, a monoalkylamine group, a dialkylamine group, an N-alkylarylamine group, a monoarylamine group, a diarylamine group, an N-arylheteroarylamine group, an N-alkylheteroarylamine group, a monoheteroarylamine group, and a diheteroarylamine group, and the number of carbon atoms is not particularly limited, and may be 1 to 30. Specific examples of the amine group include, but are not limited to, methylamine, dimethylamine, ethylamine, diethylamine, phenylamine, naphthylamine, biphenylamine, anthracenylamine, 9-methyl-anthracenylamine, diphenylamine, ditolylamine, N-phenylbiphenylamine, N-phenylnaphthylamine, N-biphenylnaphthylamine, ditolylamine, N-phenyltolylamine, triphenylamine, N-naphthylfluorenylamine, N-phenylphenanthrenylamine, N-biphenylphenanthrenylamine, N-phenylfluorenylamine, N-phenylterphenylamine, N-phenanthrenylfluorenylamine, and N-biphenylfluorenylamine. The amine group may be substituted or unsubstituted, and when substituted, examples of the substituent are as described above.

[0028] As used herein, an N-alkylarylamine group refers to an amine group in which the N of the amine group is substituted with an alkyl group and an aryl group. As used herein, an N-arylheteroarylamine group refers to an amine group in which the N of the amine group is substituted with an aryl group and a heteroaryl group. As used herein, an N-alkylheteroarylamine group refers to an amine group in which the N of the amine group is substituted with an alkyl group and a heteroarylamine group.

[0029] In this specification, the alkyl group in the monoalkylamine group, dialkylamine group, N-arylalkylamine group, alkylthioxy group, alkylsulfoxy group, and N-alkylheteroarylamine group is as exemplified above for the alkyl group. Specifically, the alkylthioxy group includes methylthioxy group, ethylthioxy group, tert-butylthioxy group, hexylthioxy group, and octylthioxy group, and the alkylsulfoxy group includes mesyl, ethylsulfoxy group, propylsulfoxy group, and butylsulfoxy group, but is not limited thereto.

[0030] In this specification, the alkenyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but may be 2 to 40. The above description of the alkyl group is applicable to the alkenyl group, except that the alkenyl group contains at least one unsaturated bond (double bond or triple bond) in the functional group. According to one embodiment, the number of carbon atoms of the alkenyl group is 2 to 20. According to another embodiment, the number of carbon atoms of the alkenyl group is 2 to 10. According to another embodiment, the number of carbon atoms of the alkenyl group is 2 to 6. Specific examples include, but are not limited to, vinyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 3-methyl-1-butenyl, 1,3-butadienyl, allyl, 1-phenylvinyl-1-yl, 2-phenylvinyl-1-yl, 2,2-diphenylvinyl-1-yl, 2-phenyl-2-(naphthyl-1-yl)vinyl-1-yl, 2,2-bis(diphenyl-1-yl)vinyl-1-yl, stilbenyl group, styrenyl group, etc. The alkenyl group may be substituted or unsubstituted, and if substituted, examples of the substituent are as described above.

[0031] In this specification, the cycloalkenyl group may have 3 to 60 carbon atoms, and according to one embodiment, the cycloalkenyl group has 3 to 30 carbon atoms. According to another embodiment, the cycloalkenyl group has 3 to 20 carbon atoms. According to another embodiment, the cycloalkenyl group has 3 to 6 carbon atoms. The above description of the cycloalkyl group is applicable to the cycloalkenyl group, except that the cycloalkenyl group contains at least one unsaturated bond (double bond or triple bond) in the functional group. The cycloalkenyl group may be substituted or unsubstituted, and if substituted, examples of the substituent are as described above.

[0032] In the present specification, specific examples of the silyl group include, but are not limited to, a trimethylsilyl group, a triethylsilyl group, a t-butyldimethylsilyl group, a vinyldimethylsilyl group, a propyldimethylsilyl group, a triphenylsilyl group, a diphenylsilyl group, a phenylsilyl group, etc. The silyl group may be substituted or unsubstituted, and if substituted, examples of the substituent are as described above.

[0033] In the present specification, the boron group specifically includes, but is not limited to, a trimethyl boron group, a triethyl boron group, a t-butyl dimethyl boron group, a triphenyl boron group, a phenyl boron group, etc. The boron group may be substituted or unsubstituted, and if substituted, examples of the substituent are as described above.

[0034] In the present specification, specific examples of the phosphine oxide group include, but are not limited to, a diphenylphosphine oxide group, a dinaphthylphosphine oxide group, etc. The phosphine oxide group may be substituted or unsubstituted, and if substituted, examples of the substituent are as described above.

[0035] In the present specification, the aryl group is not particularly limited, and may have 6 to 60 carbon atoms, and may be a monocyclic aryl group or a polycyclic aryl group. According to one embodiment, the aryl group has 6 to 30 carbon atoms. According to one embodiment, the aryl group has 6 to 20 carbon atoms. The aryl group may be a monocyclic aryl group, such as a phenyl group, a biphenyl group, a terphenyl group, etc., but is not limited thereto. The polycyclic aryl group may be a naphthyl group, an anthracenyl group, etc., but is not limited thereto. The aryl group may be substituted or unsubstituted, and if substituted, examples of the substituent are as described above.

[0036] In this specification, the aryl group in the monoarylamine group, diarylamine group, aryloxy group, arylthioxy group, arylsulfoxy group, N-arylalkylamine group, N-arylheteroarylamine group and arylphosphine group is as described above as an example of the aryl group. Specifically, aryloxy groups include phenoxy groups, p-tolyloxy groups, m-tolyloxy groups, 3,5-dimethyl-phenoxy groups, 2,4,6-trimethylphenoxy groups, p-tert-butylphenoxy groups, 3-biphenyloxy groups, 4-biphenyloxy groups, 1-naphthyloxy groups, 2-naphthyloxy groups, 4-methyl-1-naphthyloxy groups, 5-methyl-2-naphthyloxy groups, 1-anthryloxy groups, 2-anthryloxy groups, 9-anthryloxy groups, 1-phenanthryloxy groups, 3-phenanthryloxy groups, and 9-phenanthryloxy groups; arylthioxy groups include phenylthioxy groups, 2-methylphenylthioxy groups, and 4-tert-butylphenylthioxy groups; and arylsulfoxy groups include benzenesulfoxy groups and p-toluenesulfoxy groups, but are not limited thereto.

[0037] In this specification, the heterocyclic group is a heterocyclic group containing one or more of O, N, Se and S as a hetero element, and the number of carbon atoms is not particularly limited, but may be 2 to 60 carbon atoms. Examples of heterocyclic groups include, but are not limited to, thiophene, furan, pyrrole, imidazole, thiazole, oxazole, oxadiazole, triazole, pyridyl, bipyridyl, pyrimidyl, triazine, acridyl, pyridazine, pyrazinyl, quinolinyl, quinazoline, quinoxalinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinoline, indole, carbazole, benzoxazole, benzimidazole, benzothiazole, benzocarbazole, benzothiophene, dibenzothiophene, benzofuranyl, phenanthroline, thiazolyl, isoxazolyl, oxadiazolyl, thiadiazolyl, benzothiazolyl, phenothiazinyl, and dibenzofuranyl groups.

[0038] In this specification, a heteroaryl group includes one or more non-carbon atoms, heteroatoms, and specifically, the heteroatoms may include one or more atoms selected from the group consisting of O, N, Se, S, etc. The number of carbon atoms is not particularly limited, but may be 2 to 60, and the heteroaryl group may be monocyclic or polycyclic. Examples of the heteroaryl group include a thiophene group, a furanyl group, a pyrrole group, an imidazolyl group, a thiazolyl group, an oxazolyl group, an oxadiazolyl group, a pyridyl group, a bipyridyl group, a pyrimidyl group, a triazinyl group, a triazolyl group, an acridyl group, a pyridazinyl group, a pyrazinyl group, a quinolinyl group, a quinazolinyl group, a quinoxalinyl group, a phthalazinyl group, a pyridopyrimidyl group, a pyridopyrazinyl group, a pyrazinopyrazinyl group, an isoquinolinyl group, an indolyl group, a carbazolyl group, a benzoxazolyl group, a benzimidazolyl group, a benzothiazolyl group, a benzocarbazolyl group, a benzothiophene group, a dibenzothiophene group, Examples of heteroaryl groups include, but are not limited to, benzofuranyl, phenanthrolinyl, thiazolyl, isoxazolyl, oxadiazolyl, thiadiazolyl, benzothiazolyl, phenothiazinyl, aziridyl, azaindolyl, isoindolyl, indazolyl, purine, pteridine, beta-carbolyl, naphthyridyl, ter-pyridyl, phenazinyl, imidazopyridyl, pyropyridyl, azepine, pyrazolyl, and dibenzofuranyl. The heteroaryl group may be substituted or unsubstituted, and if substituted, examples of the substituent are as described above.

[0039] In this specification, examples of the heteroaryl group in the monoheteroarylamine group, diheteroarylamine group, N-arylheteroarylamine group and N-alkylheteroarylamine group can be selected from the examples of the heteroaryl group mentioned above.

[0040] In this specification, an alkylene group is a divalent functional group derived from an alkane, and may be, for example, a linear or branched chain, methylene group, ethylene group, propylene group, isobutylene group, sec-butylene group, tert-butylene group, pentylene group, hexylene group, etc. The alkylene group may be substituted or unsubstituted, and if substituted, examples of the substituent are as described above.

[0041] In this specification, the haloalkylene group refers to a functional group in which the above-mentioned alkylene group is substituted with a halogen group, and may be, for example, perfluoropropane-2,2-diyl.

[0042] In this specification, the alkenylene group is a divalent functional group derived from alkenyl, and the above description of the alkenyl group is applicable except that it is a divalent functional group. The alkenylene group may be substituted or unsubstituted, and if substituted, examples of the substituent are as described above.

[0043] In this specification, the cycloalkylene group is a divalent functional group derived from a cycloalkane, and the above description of the cycloalkyl group is applicable except that it is a divalent functional group. The cycloalkylene group may be substituted or unsubstituted, and if substituted, examples of the substituent are as described above.

[0044] In this specification, the cycloalkenylene group is a divalent functional group derived from cycloalkenyl, and the above description of the cycloalkenyl group is applicable except that it is a divalent functional group. The cycloalkenylene group may be substituted or unsubstituted, and if substituted, examples of the substituent are as described above.

[0045] In this specification, the arylene group means an aryl group having two bonding positions, that is, a divalent functional group. The above-mentioned explanation of the aryl group is applicable except that each of these is a divalent functional group. The arylene group may be substituted or unsubstituted, and when substituted, examples of the substituent are as described above.

[0046] 1. Salt compounds According to one embodiment of the present invention, there is provided a salt compound including an anion represented by the following Chemical Formula 1 and a cation represented by the following Chemical Formula 2: [Chemical formula 1] JPEG2025500244000009.jpg35170[Chemical formula 2] JPEG2025500244000010.jpg16170

[0047] In the above Chemical Formulas 1 and 2, R1 and R2 are the same or different and each independently represents an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, or a combination thereof; X represents a direct bond, an alkylene group, an alkenylene group, a cycloalkylene group, a cycloalkenylene group, an arylene group, or a combination thereof; M + is one of an onium ion or a metal ion.

[0048] The combination of functional groups in R1, R2, and X means a combined functional group containing two or more functional groups together, such as an arylalkyl group that contains both an aryl group and an alkyl group.

[0049] at least one or more hydrogen atoms contained in the alkyl group, alkenyl group, cycloalkyl group, cycloalkenyl group, aryl group, alkylene group, alkenylene group, cycloalkylene group, cycloalkenylene group, and arylene group are each independently substituted or unsubstituted with one or more substituents selected from the group consisting of deuterium; halogen; cyano group; nitro group; hydroxy group; carbonyl group; ester group; imide group; amide group; amino group; carboxy group; sulfonic acid group; sulfonamide group; phosphine oxide group; alkoxy group; alkylcarbonyl group; alkoxycarbonyl group; sulfonyloxy group; aryloxy group; alkylthioxy group; arylthioxy group; alkylsulfoxy group; arylsulfoxy group; silyl group; and boron group;

[0050] at least one or more carbon atoms contained in the alkyl group, alkenyl group, cycloalkyl group, cycloalkenyl group, aryl group, alkylene group, alkenylene group, cycloalkylene group, cycloalkenylene group, and arylene group are each independently substituted or unsubstituted with a hetero element; The alkyl group, the alkenyl group, the alkylene group, and the alkenylene group are each independently linear or branched; The cycloalkyl groups, cycloalkenyl groups, aryl groups, cycloalkylene groups, cycloalkenylene groups, and arylene groups are each independently monocyclic or polycyclic.

[0051] The present inventors have confirmed through experiments that the salt compound of one embodiment, as represented by Chemical Formula 1, is more polarized by the sulfonyloxy group (-SO3-) contained in the anion structure, thereby shortening the diffusion length of the anion generated from the acid diffusion inhibitor during exposure, thereby ensuring high contrast, improving the limiting resolution, and obtaining low sensitivity, LER value, and high process margin, and have completed the invention.

[0052] In contrast, when a sulfonyl group (-SO2-) is contained instead of the above-mentioned sulfonyloxy group (-SO3-), the polarity is reduced due to the reduction in oxygen atoms, and there is a limit to how short the diffusion length of the anions generated from the acid diffusion inhibitor during exposure can be.

[0053] In addition, in the anion structure represented by Chemical Formula 1, when the sulfonyloxy group (-SO3-) and the nitrogen (N) atom are bonded via an intermediate functional group represented by X, the miscibility with other components constituting the resist is improved, improving the distribution uniformity in the thin resist film. In addition, the acid diffusion suppression effect is increased, so that the contrast between exposed and unexposed areas is improved, and line width roughness can be improved.

[0054] On the other hand, when the above-mentioned sulfonyloxy group (-SO3-) is directly bonded to a nitrogen (N) atom, or when two sulfonyl groups (-SO2-) are directly bonded to a nitrogen (N) atom, the polarity is reduced due to the reduction in oxygen atoms, the acid diffusion inhibition efficiency is reduced, and miscibility with the resist components is reduced, resulting in poor distribution uniformity within the thin film. As a result, the contrast between exposed and unexposed areas becomes insufficient, which can lead to problems such as reduced process margins and increased line width roughness.

[0055] Specifically, in the anion represented by Chemical Formula 1, X may be one of a direct bond, an alkylene group, an alkenylene group, a cycloalkylene group, a cycloalkenylene group, an arylene group, or a combination thereof. Specifically, in Chemical Formula 1, X may be one of an alkylene group having 1 to 30 carbon atoms, an alkenylene group having 1 to 30 carbon atoms, a cycloalkylene group having 3 to 30 carbon atoms, a cycloalkenylene group having 3 to 30 carbon atoms, or an arylene group having 6 to 30 carbon atoms.

[0056] Specifically, X may be an alkylene group or an alkenylene group, in which case the reactivity is excellent and a high yield can be obtained. The alkylene group having 1 to 30 carbon atoms may be an alkylene group having 1 to 20 carbon atoms, or 1 to 10, or 1 to 8, or 1 to 3, or 2 to 6 carbon atoms. More specifically, in the above Chemical Formula 1, X is an alkylene group having 2 to 3 carbon atoms.

[0057] In the above formula 1, specific examples of X are not particularly limited, but examples include ethylene and propylene. In the above formula 1, when X is an alkylene group having 2 to 3 carbon atoms, crystallinity is improved during purification, and a high-purity material can be obtained in high yield. On the other hand, when X is an alkylene group having more than 3 carbon atoms, purification is difficult due to side reactions and gel properties, which may result in a problem of reduced yield. Specific examples of X in the above chemical formula 1 include butylene, pentylene, hexylene, heptylene, and octylene.

[0058] Meanwhile, in the anion represented by the above chemical formula 1, R1 and R2 may be the same or different, and each independently may be one of an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, a halogen, or a combination thereof.

[0059] Specifically, in the above Chemical Formula 1, R1 may be an alkyl group having 1 to 30 carbon atoms and having an unsubstituted hydrogen atom. Specific examples of the alkyl group having 1 to 30 carbon atoms and having an unsubstituted hydrogen atom are not particularly limited, but may include, for example, one of methyl, ethyl, and propyl.

[0060] In addition, in the above Chemical Formula 1, R1 may be an aryl group having 6 to 30 carbon atoms and having an unsubstituted hydrogen atom. Specific examples of the aryl group having 6 to 30 carbon atoms and having an unsubstituted hydrogen atom are not particularly limited, but one example is phenyl.

[0061] In addition, in the above Chemical Formula 1, R1 may be a halogen. Specific examples of the halogen are not particularly limited, but include fluorine, chlorine, bromine, and iodine.

[0062] Furthermore, in the above Chemical Formula 1, R1 may be a cycloalkyl group having 3 to 30 carbon atoms and having unsubstituted hydrogen atoms. Specific examples of the cycloalkyl group having 3 to 30 carbon atoms and having unsubstituted hydrogen atoms are not particularly limited, but examples include cyclohexyl and adamantyl.

[0063] In addition, in the above Chemical Formula 1, R1 may be an alkyl group having 1 to 30 carbon atoms in which at least one hydrogen atom is substituted with a halogen, or an aryl group having 6 to 30 carbon atoms in which at least one hydrogen atom is substituted with a halogen, or an aryl group having 1 to 30 carbon atoms in which at least one hydrogen atom is substituted with a halogenated alkyl group, thereby increasing the exposure light source absorption efficiency and improving the resolution.

[0064] Specific examples of the alkyl group having 1 to 30 carbon atoms in which at least one hydrogen atom is substituted with a halogen are not particularly limited, but include trifluoromethyl as an example.

[0065] Specific examples of the aryl group having 6 to 30 carbon atoms in which at least one hydrogen atom is substituted with a halogen are not particularly limited, but include, for example, one of 4-fluorophenyl, 4-bromophenyl, 4-iodophenyl, 2,5-difluorophenyl, 2,4-difluorophenyl, 4-(trifluoromethyl)phenyl, and 1,2,3,4,5-pentafluorophenyl.

[0066] Specifically, in Chemical Formula 1, R1 may be one of an alkyl group having 1 to 30 carbon atoms in which 2 to 6 hydrogen atoms are substituted with halogen, or an aryl group having 6 to 30 carbon atoms in which 2 to 6 hydrogen atoms are substituted with halogen. As a result, the exposure light source absorption efficiency increases in the exposed area, and the acid diffusion suppression efficiency increases, which improves the contrast between the exposed area and the non-exposed area, thereby increasing the resolving power.

[0067] Specific examples of the alkyl group having 1 to 30 carbon atoms in which 2 to 6 hydrogen atoms have been substituted with halogen are not particularly limited, but include, for example, one of trifluoromethyl.

[0068] Specific examples of the aryl group having 6 to 30 carbon atoms in which 2 to 6 hydrogen atoms are substituted with halogen are not particularly limited, but include, for example, one of 4-trifluoromethylphenyl, 4-fluorophenyl, 2,5-difluorophenyl, 2,4-difluorophenyl, 4-(trifluoromethyl)phenyl, and 1,2,3,4,5-pentafluorophenyl.

[0069] Specifically, in the above Chemical Formula 1, R1 may be one of methyl, ethyl, propyl, halogen, trifluoromethyl, cyclohexyl, adamantyl, phenyl, 4-fluorophenyl, 4-bromophenyl, 4-iodophenyl, 2,4-difluorophenyl, 2,5-difluorophenyl, 4-(trifluoromethyl)phenyl, or 1,2,3,4,5-pentafluorophenyl.

[0070] Meanwhile, in the above formula 1, R2 may be a substituted or unsubstituted aryl group. When the unsaturated aromatic group R2 in the above formula 1 is selected and substituted, more secondary electrons can be generated in the resist thin film due to increased electron beam or EUV photon absorption, thereby improving sensitivity.

[0071] Specifically, R2 may be one of an aryl group in which at least one hydrogen atom is substituted with a halogen, an aryl group in which no hydrogen atom is substituted, or an aryl group in which at least one hydrogen atom is substituted with a heteroalkyl group.

[0072] Preferably, R2 may be an aryl group in which at least one hydrogen atom is substituted with a halogen. In particular, iodine is preferred among halogen elements in terms of improving the efficiency of generating secondary electrons. Specific examples of the aryl group in which at least one hydrogen atom is substituted with a halogen are not particularly limited, but examples include 4-fluorophenyl, 4-bromophenyl, 4-iodophenyl, 2,5-difluorophenyl, 2,4-difluorophenyl, and 1,2,3,4,5-pentafluorophenyl.

[0073] On the other hand, R2 may be an aryl group in which the hydrogen atom is unsubstituted. Specific examples of the aryl group in which the hydrogen atom is unsubstituted include, but are not limited to, 1-naphthyl, 2-naphthyl, 4-pyridinyl, 6-benzoxazolyl, 5-phthalanyl, 1,4-benzodioxan-6-yl, acetyl-4-piperidinyl, and tert-butoxycarbonyl-4-piperidinyl.

[0074] R2 may be an aryl group in which at least one hydrogen atom is substituted with a heteroalkyl group. A specific example of the heteroalkyl group is an alkoxy group, and a specific example of the aryl group in which at least one hydrogen atom is substituted with a heteroalkyl group is not particularly limited, but may be 4-methoxyphenyl.

[0075] Meanwhile, R2 may be one of an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, or a combination thereof. More specifically, the alkyl group, the alkenyl group, the cycloalkyl group, and the cycloalkenyl group may have unsubstituted hydrogen atoms. Specific examples of the unsubstituted alkyl group, the alkenyl group, the cycloalkyl group, the cycloalkenyl group, or a combination thereof include, but are not limited to, methyl, ethyl, propyl, trifluoromethyl, cyclohexyl, adamantyl, or 1,4-dioxane-2-ylethyl.

[0076] In addition, R2 may be one of an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, or a combination thereof, in which at least one hydrogen atom is substituted with a heteroalkyl group. Specific examples of the heteroalkyl group include an alkoxy group.

[0077] More specifically, in the above Chemical Formula 1, R2 may be one of methyl, ethyl, propyl, trifluoromethyl, cyclohexyl, adamantyl, acetyl-4-piperidinyl, tert-butoxycarbonyl-4-piperidinyl, 4-fluorophenyl, 4-bromophenyl, 4-iodophenyl, 2,5-difluorophenyl, 2,4-difluorophenyl, 1,2,3,4,5-pentafluorophenyl, 4-methoxyphenyl, 1-naphthyl, 2-naphthyl, 4-pyridinyl, 6-benzoxazolyl, 5-phthalanyl, 1,4-dioxan-2-ylethyl, or 1,4-benzodioxan-6-yl.

[0078] Specific examples of the anion represented by the above Chemical Formula 1 are not particularly limited, but may be any one selected from the group consisting of the following: [ka] [ka]

[0079] Meanwhile, in the above Chemical Formula 2, M + may be one of an onium ion or a metal ion. + may be one of the onium ions: sulfonium ion, iodonium ion, or ammonium ion.

[0080] Specific examples of the cation represented by the above formula 2 are not particularly limited, but may be any one selected from the group consisting of the following: [ka] [ka]

[0081] The specific example of the method for synthesizing the salt compound is not particularly limited, but as an example, the salt compound can be synthesized according to the following reaction formula 1. [Reaction Scheme 1] JPEG2025500244000015.jpg42170

[0082] In the reaction formula 1, R1, R2, X, and M are the same as R1, R2, X (chemical formula 1), and M (chemical formula 2) of the salt compound, respectively. Y is a counter anion, and Base is a base.

[0083] First, compound 1-a can be reacted with compound 1-b or compound 1-c to obtain compound 1-d. Compound 1-d can be reacted again with compound 1-e or compound 1-f to obtain compound 1-g, where compounds 1-e and 1-f can be the same as or different from compounds 1-b and 1-c. Compound 1-g can be reacted with compound 1-h to obtain compound A.

[0084] In the above reaction, the nucleophilic reaction of the amine group occurs more frequently than the nucleophilic reaction of the alcohol group in the synthesis reaction to obtain compound 1-d, but in order to selectively induce the amine group substitution reaction, compound 1-b or compound 1-c can be slowly added dropwise while maintaining the reaction temperature below -40°C and above -78°C. When compound 1-b and compound 1-e have the same structure, it is sufficient to slowly add compound 1-b or 1-e at 0°C, and then slowly raise the temperature to room temperature naturally, and compound 1-g can also be obtained in a similar manner.

[0085] The method for obtaining a salt compound by reacting compound 1-g with compound 1-h is not particularly limited, and the compound can be obtained by dissolving compound 1-g in a suitable organic solvent and water in the presence of a suitable alkali metal hydroxide, adding compound 1-h, and then stirring the mixture so that the organic layer and the aqueous layer are thoroughly mixed.

[0086] The alkali metal hydroxide in the reaction is not particularly limited, and common sodium hydroxide, potassium hydroxide, etc. can be used, and the amount used is 1 mole or more and 2 moles or less per mole of compound 1-g.

[0087] In the reaction, the organic solvent may be a solvent that dissolves the product salt compound well, such as dichloromethane or chloroform, and the amount used may be 15 parts by mass or more and 20 parts by mass or less based on compound 1-g.

[0088] The amount of compound 1-h used in the reaction may usually be 1 mole or more and 3 moles or less per mole of compound 1-g, the reaction time varies depending on the reactivity, reaction concentration, etc., but may usually be 10 hours or more and 24 hours or less, and the reaction temperature may be 20°C or more and 50°C or less.

[0089] After the reaction is completed, the aqueous layer and the organic layer are separated, and the compound A dissolved in the organic layer can be purified by a method selected from conventionally known purification methods such as solvent extraction, concentration, chromatography, crystallization, and recrystallization, either alone or in combination. This method can be applied to the purification of not only the final compound A but also compounds 1-d, 1-g, and 1-h synthesized in each step.

[0090] 2. Acid diffusion inhibitor Meanwhile, according to another embodiment of the present invention, there is provided an acid diffusion inhibitor (quencher) including the salt compound of the above embodiment. The content regarding the salt compound includes the content described above regarding the one embodiment.

[0091] The acid diffusion inhibitor is a material capable of controlling the acid diffusion distance, and acts as a quencher that inhibits acid diffusion in non-exposed areas, and acts as an acid by being photodecomposed in exposed areas, thereby maintaining a relatively high acid concentration in the exposed areas and increasing the acid distribution contrast between the exposed and non-exposed areas, thereby improving lithography properties.

[0092] As the acid diffusion inhibitor used in the present invention, in addition to the above-mentioned salt compound, the acid diffusion inhibitor for normal photoresist can be mixed and used without any restrictions.Examples of the acid diffusion inhibitor for normal photoresist include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds with carboxyl groups, nitrogen-containing compounds with sulfonyl groups, nitrogen-containing compounds with hydroxyl groups, nitrogen-containing compounds with hydroxyphenyl groups, alcoholic nitrogen-containing compounds, amides, imides, carbamates, etc.

[0093] 3. Photoresist composition Meanwhile, according to yet another embodiment of the present invention, there is provided a photoresist composition comprising the salt compound of the above embodiment; a photoacid generator; a base polymer; and an organic solvent.

[0094] The content of the salt compound includes the content described above in relation to the embodiment. The content of the salt compound or the acid diffusion inhibitor containing the salt compound may be 0.01 parts by weight or more and 30 parts by weight or less, or 0.1 parts by weight or more and 23 parts by weight or less, relative to 100 parts by weight of the base polymer. If the content of the salt compound or the acid diffusion inhibitor containing the salt compound exceeds the above range, a large amount of acid may be generated, resulting in a pattern with a poor cross section, and the contrast of the pattern may be reduced.

[0095] Meanwhile, the base polymer has a property that its solubility in a developer changes under the action of an acid, and photosensitive polymers used in general photoresist compositions can be used without any restrictions.

[0096] As a specific example, the base polymer may contain a repeating unit represented by the following chemical formula a or chemical formula b. The base polymer may be a homopolymer consisting of one type of repeating unit represented by the chemical formula a, a homopolymer consisting of one type of repeating unit represented by the chemical formula b, a copolymer consisting of two or more types of repeating units represented by the chemical formula a, a copolymer consisting of two or more types of repeating units represented by the chemical formula b, or a copolymer consisting of one or more types of repeating units represented by the chemical formula a and one or more types of repeating units represented by the chemical formula b. [Chemical formula a] JPEG2025500244000016.jpg24170

[0097] In the above chemical formula a, R3 may be hydrogen or a methyl group, and Ar may be an aryl group in which at least one hydrogen atom is substituted or unsubstituted. The aryl group may be monocyclic or polycyclic. Examples of the substituent are not particularly limited, and include one or more substituents selected from the group consisting of deuterium, halogen, cyano group, nitro group, hydroxyl group, carbonyl group, ester group, imide group, amide group, amino group, carboxyl group, sulfonic acid group, sulfonamide group, phosphine oxide group, alkoxy group, alkylcarbonyl group, alkoxycarbonyl group, sulfonyloxy group, aryloxy group, alkylthiooxy group, arylthiooxy group, alkylsulfoxy group, arylsulfoxy group, silyl group, and boron group. More specifically, the substituent may be a halogen or a hydroxyl group. [Chemical formula b] JPEG2025500244000017.jpg45170

[0098] In the above formula b, R4 may be hydrogen or a methyl group, and R5 may be one of an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, and an aryl group. At least one hydrogen atom contained in the alkyl group, the alkenyl group, the cycloalkyl group, the cycloalkenyl group, and the aryl group may be independently substituted or unsubstituted with one or more substituents selected from the group consisting of deuterium, halogen, cyano group, nitro group, hydroxyl group, carbonyl group, ester group, imide group, amide group, amino group, carboxy group, sulfonic acid group, sulfonamide group, phosphine oxide group, alkoxy group, alkylcarbonyl group, alkoxycarbonyl group, sulfonyloxy group, aryloxy group, alkylthiooxy group, arylthiooxy group, alkylsulfoxy group, arylsulfoxy group, silyl group, and boron group.

[0099] At least one or more carbon atoms contained in the alkyl group, alkenyl group, cycloalkyl group, cycloalkenyl group, and aryl group may each independently be substituted or unsubstituted with a hetero element.

[0100] The alkyl and alkenyl groups may each independently be linear or branched, and the cycloalkyl, cycloalkenyl and aryl groups may each independently be monocyclic or polycyclic.

[0101] More specifically, the base polymer may be a photosensitive polymer (base resin) represented by the following chemical formula c. [Chemical formula c] JPEG2025500244000018.jpg46170

[0102] In the above chemical formula c, R6 to R8 are the same or different and each independently represents a hydrogen atom or a methyl group, Ar represents an aryl group in which at least one hydrogen atom is substituted or unsubstituted, R9 and R 10 are the same or different and may each independently be one of an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, or an aryl group. The Ar is the same as the Ar in the formula (a), and the R and R 10 is the same as R5 in the above chemical formula b.

[0103] More specifically, in the above chemical formula c, Ar may be a monocyclic aryl group having 6 to 11 carbon atoms in which at least one hydrogen atom is substituted with a hydroxy group.

[0104] In the above chemical formula c, R9 may be a monocyclic or polycyclic cycloalkyl group in which at least one carbon atom is substituted with a heteroatom, or a polycyclic cycloalkyl group in which at least one hydrogen atom is substituted with a hydroxyl group. In the above chemical formula c, R 10 may be a monocyclic or polycyclic cycloalkyl group.

[0105] In the formula c, a, b, and c written under the repeating unit are the mol% of each repeating unit with respect to the total monomers (repeating units) constituting the polymer, where a may be 10 mol% to 60 mol%, or 35 mol% to 40 mol%, b may be 1 mol% to 30 mol%, or 5 mol% to 20 mol%, and c may be 30 mol% to 60 mol%, or 40 mol% to 55 mol%. If the mol% of the repeating unit exceeds the above range, the physical properties of the photoresist film may be deteriorated, the photoresist film may be difficult to form, and the pattern contrast may be reduced. Usually, the weight average molecular weight (Mw) of the photosensitive polymer may be 2,000 to 20,000, or 3,000 to 12,000.

[0106] More specific examples of the photosensitive polymer (base resin) represented by the above chemical formula c include photosensitive polymers (base resins) represented by the following chemical formulas d, e, f and g. [Chemical formula d] JPEG2025500244000019.jpg24170[Chemical formula e] JPEG2025500244000020.jpg27170[Chemical formula f] JPEG2025500244000021.jpg25170[Chemical formula g] JPEG2025500244000022.jpg26170

[0107] The content of the base polymer may be 2 to 30% by weight, or 4 to 10% by weight, based on the total weight of the photoresist composition. If the content of the base polymer is less than 2% by weight, it may be difficult to form a photoresist film and a pattern, and if it exceeds 30% by weight, the thickness distribution of the pattern formed on the wafer may not be uniform.

[0108] Examples of photoacid generators include onium salts such as sulfonium salts and iodonium salts, diazomethanes, oximes, nitrobenzylsulfonates, iminosulfonates, and disulfones, and these can be used alone or in combination of two or more.

[0109] The content of the photoacid generator may be 0.05 to 30 parts by weight, or 0.1 to 15 parts by weight, based on 100 parts by weight of the base polymer. If the content of the photoacid generator is less than 0.05 parts by weight based on 100 parts by weight of the base polymer, the photoresist may become less sensitive to light and the acid diffusion distance may become longer, while if the content exceeds 30 parts by weight, the photoacid generator may absorb a large amount of far ultraviolet light, generating a large amount of acid and causing defects in the cross section of the pattern.

[0110] The organic solvent used in the present invention can be any organic solvent that is used in ordinary photoresist compositions and that can easily dissolve the base polymer, photoacid generator, salt compound, and other additives, without any restrictions. For example, ketones such as cyclohexanone and methyl amyl ketone, alcohols such as 2-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol, ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, and diethyl glycol dimethyl ether, esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono-tert-butyl ether acetate, and lactones such as γ-butyrolactone can be used alone or in combination of two or more, but are not limited thereto. Examples of the organic solvent are not particularly limited, but as an example, any one of PGMEA (propylene glycol monomethyl ether acetate), PGME (propylene glycol monomethyl ether), EL (ethyl lactate), CyH (cyclohexanone), or a mixture thereof, which has the best solubility for the acid diffusion inhibitor, can be used.

[0111] The content of the organic solvent is the remainder excluding the content of the photoresist composition excluding the base polymer, the photoacid generator, the salt compound, and other additives, with respect to 100% by weight of the entire photoresist composition.

[0112] Examples of the additives are not particularly limited, but may include, for example, additional resins, stabilizers, surfactants, thickeners, defoamers, adhesion agents, antioxidants, and dissolution inhibitors.

[0113] According to yet another embodiment of the present invention, there can be provided a method for forming a photoresist pattern, the method including the steps of applying and heating the photoresist composition of the other embodiment to form a photoresist film, exposing the photoresist film, and developing the exposed photoresist film to form a photoresist pattern. The content relating to the photoresist composition includes the content described above in relation to the other embodiments.

[0114] The pattern formation method can be performed by applying known techniques, for example, by applying a photoresist using a spinner or the like, exposing the photoresist to high-energy rays with a wavelength of 300 nm or less using a specified photomask, and developing the exposed photoresist film with a normal developer (for example, an alkaline aqueous solution such as a tetramethylammonium hydroxide aqueous solution having a concentration of 0.1% by weight or more and 10% by weight or less).

[0115] The high-energy radiation having a wavelength of 300 nm or less is not particularly limited, but examples thereof include ultraviolet rays, far ultraviolet rays, extreme ultraviolet rays (EUV), electron beams, X-rays, excimer lasers, gamma rays, synchrotron radiation, etc. For forming fine patterns of 70 nm or less, it is preferable to use an exposure device equipped with a source of short-wavelength high-energy radiation such as an ArF excimer laser, a KrF excimer laser, or EUV.

[0116] More specifically, the high energy exposure source can be selected from KrF having a wavelength of 248 nm, ArF having a wavelength of 193 nm, an electron beam (e-beam), and EUV having a wavelength of 13.5 nm. Effect of the Invention

[0117] According to the present invention, there are provided a salt compound which has improved polarity, thereby shortening the diffusion length of anions generated upon exposure, ensuring high contrast and improving limiting resolution, and which can provide a photoresist composition having low sensitivity, LER value and high process margin, as well as an acid diffusion inhibitor and photoresist composition containing the same. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0118] Hereinafter, an example will be presented for understanding the present invention. However, the following example is provided only to facilitate understanding of the present invention, and is not intended to limit the scope of the present invention.

[0119] Example 1: Preparation of salt compound The structures of the salt compounds obtained in Examples 1-1 to 1-12 and Comparative Examples 1-1 to 1-3 are shown in Table 1 below.

[0120] [Table 1] JPEG2025500244000024.jpg213170

[0121] Example 1-1: Salt Compound 1 Step 1) Preparation of 1,1,1-trifluoro-N-(2-hydroxyethyl)methanesulfoneamide [ka]

[0122] Ethanolamine (20g) was dissolved in dichloromethane (150g) to prepare mixture 1, which was cooled to -78°C and stirred. Then, trifluoromethanesulfonic anhydride (97g) and dichloromethane (150g) were mixed to prepare mixture 2, which was slowly added dropwise to mixture 1 for about 1 hour. After the dropwise addition was completed, the temperature was maintained at -78°C for an additional hour, and then the temperature was gradually raised to 0°C and stirred for an additional 5 hours. The reaction was terminated with distilled water, and the organic layer was washed three times with distilled water to remove unreacted materials, concentrated under reduced pressure, and 1,1,1-trifluoro-N-(2-hydroxyethyl)methanesulfonamide (35.7g, 56.4% yield) was obtained by column chromatography. 1 H-NMR (CDCl3, TMS (standard material), 600MHz): 8.2(NH, s, 1H), 4.5(CH2, t, 2H), 3.7(CH2, t, 2H), 1.3(OH, s, 1H)

[0123] Step 2) Preparation of 2-(trifluoromethylsulfoneamido)ethyl 4-iodobenzenesulfonate [ka]

[0124] 1,1,1-trifluoro-N-(2-hydroxyethyl)methanesulfonamide (30 g) obtained in step 1) was dissolved in dichloromethane (200 g) and stirred while slowly adding a mixture of 4-iodobenzene-1-sulfonylchloride (50 g) and dichloromethane (200 g) dropwise, and reacted for 3 hours. After that, the organic layer was washed with distilled water until it became neutral (about pH 6-7), and the organic layer was concentrated under reduced pressure to obtain 2-(trifluoromethylsulfonamido)ethyl 4-iodobenzenesulfonate (62.3 g, 87.3% yield). 1 H-NMR(CDCl3, TMS, 600MHz): 8.5(NH, s, 1H), 8.2(CH, d, 2H), 7.5(CH, d, 2H), 4.5(CH2, t, 2H), 3.9(CH2, t, 2H)

[0125] Step 3) Preparation of triphenylsulfonium(2-(4-iodophenylsulfonyloxy)ethyl)(trifluoromethanesulfonyl)amide (salt compound 1) [ka]

[0126] 2-(trifluoromethylsulfonamido)ethyl 4-iodobenzenesulfonate (30g) obtained from step 2) was dissolved in acetonitrile (200g), 10% aqueous sodium hydroxide solution (28g) was gradually added, and the mixture was stirred at room temperature for 3 hours, followed by distillation under reduced pressure to obtain sodium (2-(4-iodophenylsulfonyloxy)ethyl)(trifluoromethanesulfonyl)amide salt (approximately 30.1g, 98.54% yield). Then, triphenylsulfonium chloride (20.56g), distilled water (200g), dichloromethane (300g), and tetrabutylammonium fluoride (0.5g) as a catalyst were added, and the mixture was thoroughly stirred at room temperature for approximately 12 hours. The organic layer was separated, washed with distilled water until it became neutral (about pH 6-7), and then concentrated under reduced pressure. Ethyl acetate (100g) was added to the concentrated solution obtained from this, and the process of removing the organic solvent was repeated three times, and then concentrated under reduced pressure to obtain triphenylsulfonium(2-(4-iodophenylsulfonyloxy)ethyl)(trifluoromethanesulfonyl)amide (salt compound 1) (39g, 87.2% yield). 1 H-NMR(CDCl3, TMS, 600MHz): 8.24(CH, d, 2H), 7.54(CH, d, 2H), 7.27-7.78(CH, m, 15H), 4.5(CH2, t, 2H), 3.7(CH2, t, 2H)

[0127] Example 1-2: Salt Compound 2 The same method as in Example 1-1 was used for preparation, and in step 2), adamantanesulfonyl chloride was used instead of 4-iodobenzene-1-sulfonyl chloride, and triphenylsulfonium(2-(adamantanesulfonyloxy)ethyl)(trifluoromethanesulfonyl)amide (salt compound 2) was obtained by ion exchange reaction.

[0128] Examples 1-3: Salt Compound 3 The compound was prepared in the same manner as in Example 1-1, except that in step 2), 4-iodobenzene-1-sulfonyl chloride was replaced with 4-methoxybenzenesulfonyl chloride, and triphenylsulfonium(2-(4-methoxyphenylsulfonyloxy)ethyl)(trifluoromethanesulfonyl)amide (salt compound 3) was obtained by ion exchange reaction.

[0129] Examples 1-4: Salt Compound 4 The compound was prepared in the same manner as in Example 1-1, except that in step 2), benzo-1,4-dioxanesulfonyl chloride was used instead of 4-iodobenzene-1-sulfonyl chloride, and triphenylsulfonium(2-(benzo-1,4-dioxanesulfonyloxy)ethyl)(trifluoromethanesulfonyl)amide (salt compound 4) was obtained by ion exchange reaction.

[0130] Examples 1-5: Salt Compound 5 The same method as in Example 1-1 was used for preparation, and in step 2), 2,3,4,5,6-Pentafluoro-N-(2-hydroxyethyl)benzenesulfoneamide was used instead of 1,1,1-trifluoro-N-(2-hydroxyethyl)methanesulfonamide, and triphenylsulfonium(2-(4-iodophenylsulfonyloxy)ethyl)(trifluorobenzenesulfonyl)amide, salt compound 5, was obtained by ion exchange reaction.

[0131] Examples 1-6: Salt Compound 6 The same method as in Example 1-1 was used for preparation, except that in step 2), naphthalene-sulfonyl chloride was used instead of 4-iodobenzene-1-sulfonyl chloride, and triphenylsulfonium(2-(naphthalenesulfonyloxy)ethyl)(trifluoromethanesulfonyl)amide (salt compound 6) was obtained by ion exchange reaction.

[0132] Examples 1-7: Salt Compound 7 The same method as in Example 1-1 was used for preparation, and in step 3), diphenyl(4-(1-iodobenzene-4-sulfonyloxy)phenyl)sulfonium chloride was used instead of triphenylsulfonium chloride, and diphenyl(4-(1-iodobenzene-4-sulfonyloxy)phenyl)sulfonium(2-(4-iodophenylsulfonyloxy)ethyl)(trifluoromethanesulfonyl)amide (Diphenyl(4-(4-iodobenzene-1-sulfonyloxy)phenyl)sulfonium(2-(naphthalenesulfonyloxy)ethyl)(trifluoromethanesulfonyl)amide, salt compound 7, was obtained by ion exchange reaction.

[0133] Examples 1-8: Salt Compound 8 The same method as in Example 1-1 was used for preparation, and in step 2), propanesulfonyl chloride was used instead of 4-iodobenzene-1-sulfonyl chloride, and triphenylsulfonium(2-(propanesulfonyloxy)ethyl)(trifluoromethanesulfonyl)amide (salt compound 8) was obtained by ion exchange reaction.

[0134] Examples 1-9: Salt Compound 9 The same method as in Example 1-1 was used for preparation, and in step 2), 2-(1,4-dioxan-2-yl)-ethanesulfonyl chloride was used instead of 4-iodobenzene-1-sulfonyl chloride, and triphenylsulfonium(2-(1,4-dioxan-2-yl)-ethanesulfonyloxy)ethyl)(trifluoromethanesulfonyl)amide (salt compound 9) was obtained by ion exchange reaction.

[0135] Examples 1-10: Salt Compound 10 The compound was prepared in the same manner as in Example 1-1, and in step 2), N-(2-hydroxyethyl)propanesulfonamide was used instead of trifluoro-N-(2-hydroxyethyl)methanesulfonamide, and triphenylsulfonium(2-(4-iodophenylsulfonyloxy)ethyl)(propanesulfonyl)amide (salt compound 10) was obtained by ion exchange reaction.

[0136] Examples 1-11: Salt Compound 11 The same method as in Example 1-1 was used for preparation, and in step 2), N-(2-hydroxyethyl)benzenesulfoneamide was used instead of trifluoro-N-(2-hydroxyethyl)methanesulfonamide, and triphenylsulfonium(2-(4-iodophenylsulfonyloxy)ethyl)(benzenesulfonyl)amide (salt compound 11) was obtained by ion exchange reaction.

[0137] Examples 1-12: Salt Compound 12 The compound was prepared in the same manner as in Example 1-1, and in step 2), trifluoro-N-(2-hydroxybutyl)methanesulfonamide (1,1,1-trifluoro-N-(2-hydroxybutyl)methanesulfoneamide) was used instead of trifluoro-N-(2-hydroxyethyl)methanesulfonamide, and triphenylsulfonium(2-(4-iodophenylsulfonyloxy)butyl)(trifluoromethanesulfone)amide (salt compound 12) was obtained by ion exchange reaction.

[0138] Comparative Example 1-1: Salt Compound 13 The salt compound 13 was used, which has the following structure: [ka]

[0139] Comparative Example 1-2: Salt Compound 14 The salt compound 14 was used, which has the following structure: [ka]

[0140] Comparative Example 1-3: Salt Compound 15 The salt compound 15 was used, which has the following structure: [ka]

[0141] <Synthesis example: Production of base polymer> Synthesis Example 1: Preparation of Polymer 1 Monomers were combined according to the repeating units listed in Table 2 below, dissolved in tetrahydrofuran (THF) to prepare a reaction solution, and copolymerized. Thereafter, the reaction solution was added dropwise to a mixed solvent of methanol, n-hexane or hexane / isopropyl alcohol, or methanol / water to remove small molecules and solidify, and the solution was repeatedly washed with the same solvent, and then separated and dried to prepare a base polymer (referred to as Polymer 1). A monomer containing a hydroxystyrene group was used in a state protected with an acetoxy group, and after the primary polymerization, a secondary hydrolysis reaction was additionally carried out, followed by a process of precipitating in water.

[0142] Synthesis Examples 2 to 4: Preparation of Polymers 2 to 4 Polymers 2 to 4 were produced in the same manner as in Synthesis Example 1 above, except that the types and amounts of monomers were changed according to the repeating units shown in Table 2 below.

[0143] After drying the base polymers produced in Synthesis Examples 1 to 4, 1 H or 13 The monomer components were analyzed by C-NMR spectroscopy, and Mw and PDI (polydispersity index, Mw / Mn) were analyzed by gel permeation chromatography (GPC), and the molecular weight (Mw) was calculated in terms of standard polystyrene using THF solvent. The types of repeating units and the analysis results of polymers 1 to 4 are shown in Table 2 below.

[0144] [Table 2]

[0145] Example 2: Preparation of photoresist composition The photoresist compositions of Examples 2-1 to 2-25 and Comparative Examples 2-1 to 2-6 were prepared by dissolving a base polymer, a photoacid generator, and an acid diffusion inhibitor in an organic solvent using the components shown in Table 3 below, and filtering the solution through a polytetrafluoroethylene (PTFE) filter having pores of 0.2 μm size.

[0146] <<Base polymer>> In Examples 2-1 to 2-25 and Comparative Examples 2-1 to 2-6, one of the polymers 1 to 4 produced in the above Synthesis Examples 1 to 4 was selected and used as the base polymer.

[0147] <<Photoacid generator>> In Examples 2-1 to 2-25 and Comparative Examples 2-1 to 2-6, one of the compounds having the following structures was selected and used as a photoacid generator (PAG). [ka]

[0148] <<Acid diffusion inhibitor>> In Examples 2-1 to 2-25, the salt compounds 1 to 12 prepared in Examples 1-1 to 1-12 were used as acid diffusion inhibitors (Quenchers). In Comparative Examples 2-1 to 2-6, the salt compounds 13 to 15 described in Comparative Examples 1-1 to 1-3 were used as acid diffusion inhibitors.

[0149] <<Organic solvents>> In Examples 2-1 to 2-25 and Comparative Examples 2-1 to 2-6, one or more of PGMEA (propylene glycol monomethyl ether acetate), PGME (propylene glycol monomethyl ether), EL (ethyl lactate), and CyH (cyclohexanone) were selected and used as the organic solvent.

[0150] [Table 3] JPEG2025500244000034.jpg144170

[0151] <Experimental Example> Experimental example 1: Resist pattern formation experiment In order to analyze the resist pattern characteristics, a silicon wafer was coated with a resist bottom organic thin film to prepare a substrate, and the photoresist compositions of Examples 2-1 to 2-20 and Comparative Examples 2-1 to 2-6 were spin-coated on the substrate to form a resist thin film. The substrate was then heated (prebaked) at a temperature of 100°C to 130°C for 60 seconds using a hot plate, (i) exposed with an ASML NXE:3400 EUV exposure device with a numerical aperture (NA) of 0.33, and then heated (post exposure bake, PEB) at a temperature of 100°C to 130°C for 60 seconds. The wafer thus heated was developed for 30 seconds with a 2.38 wt% aqueous solution of tetramethylammonium hydroxide (TMAH) to form a 1:1 line and space (L / S: line / space) pattern with a film thickness dimension of 40 nm and a line width dimension of 20 nm.

[0152] Experimental Example 2: Resist pattern characteristic evaluation The pattern size of the patterned wafer of Experimental Example 1 was measured using a Hitachi High-Technologies Corp. Critical Dimension Scanning Electron Microscope (CD-SEM, product name: CG-5000) to measure the pattern size, and the sensitivity, line edge roughness (LER), and process margin (EL and DOF) were evaluated as follows.

[0153] (1) Sensitivity evaluation The optimum exposure energy, Eop (mJ / cm), at which a resist pattern having a space of the same size (pitch 40 nm) is formed for a resist line width of 20 nm. 2 The lower the sensitivity value, the lower the LER, and the larger the process margin (EL, DOF), the better the evaluation.

[0154] (2) LER evaluation (Line Edge Roughness) For a 20 nm pattern formed with optimal exposure energy (Eop), the line edge roughness was measured in the longitudinal direction of the line width pattern at 200 measurement points, and the average value was calculated for three times the standard deviation (s) (3s). The lower the LER value, the better the evaluation.

[0155] (3)EL Margin Evaluation (Exposure Latitude, unit: %) The EL margin was calculated using the exposure energy value when a 20 nm size pattern formed with the optimum exposure energy (Eop) was formed within a line width of 20 nm ±5% (19 nm to 21 nm). The higher the EL margin value, the better the evaluation. EL margin (%) = (|E1-E2| / Eop) x 100 E1: Exposure energy value when forming a line width of 19 nm (mJ / cm 2 ) E2: Exposure energy value when forming a line width of 21 nm pattern (mJ / cm 2 )

[0156] (4) DOF margin evaluation (Depth of focus, unit: nm) The change in depth of focus (DOF) at the optimal exposure energy (Eop) was calculated as a change in depth of focus having a value within the range of ±1.5% (19.7 nm to 20.3 nm) of the 20 nm pattern line width of 20 nm. The formula for this is as follows. It can be evaluated that the higher the DOF margin value, the better. DOF margin (nm) = D1 + D2 Here, D1: When a pattern with a line width of ±1.5% is formed + depth of focus value (nm) D2: Depth of focus value (nm) when a pattern with a line width of ±1.5% is formed The results of the above-mentioned evaluation of the resist pattern characteristics are shown in Table 4 below.

[0157] [Table 4] JPEG2025500244000036.jpg99170

[0158] Referring to Table 4, when the photoresist compositions according to Examples 2-1 to 2-25 were used, the radiation intensity was 55 mJ / cm 2 More than 74mJ / cm 2 The results showed a sensitivity of 2.34 nm or more and an LER of 2.84 nm or less, an EL margin of 9.1% or more and 12.4% or less, and a DOF margin of 80 nm or more and 100 nm or less.

[0159] In contrast, when the photoresist compositions of Comparative Examples 2-1 to 2-5 were used, the radiation intensity was 79 mJ / cm 2 More than 86mJ / cm 2 It was confirmed that the comparative example 2-6 using salt compound 14 had poorer physical properties than the examples, with the following sensitivity, LER of 3.25 nm to 3.58 nm, EL margin of 9.3% to 11.9%, and DOF margin of 70 nm to 80 nm. In particular, it was confirmed that the comparative example 2-6 using salt compound 14 had excellent sensitivity, but had poorer physical properties than the examples, with an LER of 3.61 nm and a DOF margin of 60 nm.

Claims

1. A salt compound containing an anion represented by the following chemical formula 1 and a cation represented by the following chemical formula 2: [Chemical formula 1] [Chemical formula 2] In the above Chemical Formulas 1 and 2, R １ and R ２ are the same or different and each independently represent one of an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, a halogen, or a combination thereof; X is one of a direct bond, an alkylene group, an alkenylene group, a cycloalkylene group, a cycloalkenylene group, an arylene group, or a combination thereof; M ＋ is one of an onium ion or a metal ion.

2. The salt compound according to claim 1 , wherein X is an alkylene group or an alkenylene group.

3. The salt compound according to claim 1, wherein X is an alkylene group having 2 to 3 carbon atoms.

4. The R １ is one of an alkyl group having 1 to 30 carbon atoms in which at least one hydrogen atom is substituted with a halogen, an aryl group having 6 to 30 carbon atoms in which at least one hydrogen atom is substituted with a halogen, or an aryl group having 6 to 30 carbon atoms in which at least one hydrogen atom is substituted with a halogenated alkyl group.

5. The R １ is one of an alkyl group having 1 to 30 carbon atoms in which 2 to 6 hydrogen atoms are substituted with halogen, or an aryl group having 6 to 30 carbon atoms in which 2 to 6 hydrogen atoms are substituted with halogen.

6. The R ２ The salt compound of claim 1 , wherein is a substituted or unsubstituted aryl group.

7. The R ２ is one of an aryl group having at least one hydrogen atom substituted with a halogen, an aryl group having no hydrogen atoms, or an aryl group having at least one hydrogen atom substituted with a heteroalkyl group.

8. The R ２ The salt compound according to claim 1 , wherein is an aryl group in which at least one hydrogen atom is substituted with a halogen.

9. The R １ is one of methyl, ethyl, propyl, halogen, trifluoromethyl, cyclohexyl, adamantyl, phenyl, 4-fluorophenyl, 4-bromophenyl, 4-iodophenyl, 2,4-difluorophenyl, 2,5-difluorophenyl, 4-(trifluoromethyl)phenyl, or 1,2,3,4,5-pentafluorophenyl.

10. The R ２ is one of methyl, ethyl, propyl, trifluoromethyl, cyclohexyl, adamantyl, acetyl-4-piperidinyl, tert-butoxycarbonyl-4-piperidinyl, 4-fluorophenyl, 4-bromophenyl, 4-iodophenyl, 2,5-difluorophenyl, 2,4-difluorophenyl, 1,2,3,4,5-pentafluorophenyl, 4-methoxyphenyl, 1-naphthyl, 2-naphthyl, 4-pyridinyl, 6-benzoxazolyl, 5-phthalanyl, 1,4-dioxan-2-ylethyl, or 1,4-benzodioxan-6-yl.

11. Said M ＋ 2. The salt compound of claim 1, wherein is one of a sulfonium ion, an iodonium ion, or an ammonium ion.

12. The salt compound according to claim 1, wherein the anion represented by the chemical formula 1 is any one selected from the group consisting of: 【Chemistry 5】 【Chemistry 6】

13. The salt compound according to claim 1, wherein the cation represented by the chemical formula 2 is any one selected from the group consisting of: 【Chemistry 7】 【Chemistry 8】

14. An acid diffusion inhibitor comprising the salt compound according to claim 1.

15. A salt compound according to claim 1; Photoacid generator; A base polymer; and A photoresist composition comprising an organic solvent.

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