Radiation-sensitive composition, pattern formation method, and compound

Abstract

The purpose of the present invention is to provide a radiation-sensitive composition that makes it possible to achieve a sufficient level of storage stability and sufficient levels of sensitivity, exposure margin, depth of focus, pattern rectangularity, development defect performance, CDU, and pattern circularity during resist pattern formation, a pattern formation method, and a compound. A radiation-sensitive composition according to the present invention contains a polymer (A), a first radiation-sensitive acid generator (B) that is represented by formula (1), a second radiation-sensitive acid generator (C) that generates sulfonic acid (excluding anything that corresponds to the first radiation-sensitive acid generator (B)), and a solvent (E).

Description

Radiation-sensitive composition, pattern-forming method, and compound

[0001] The present invention relates to a radiation-sensitive composition, a pattern-forming method, and a compound.

[0002] Photolithography, which uses resist compositions, is employed to form fine circuits in semiconductor devices. A typical procedure involves, for example, generating acid by irradiating a resist composition film with radiation through a mask pattern. This acid then acts as a catalyst, creating a difference in the solubility of the polymer in alkaline or organic developers between the exposed and unexposed areas, thereby forming a resist pattern on the substrate.

[0003] In the above photolithography techniques, from the perspective of pattern miniaturization, there is progress in replacing existing lasers with g-ray, i-ray, and KrF excimer lasers. Furthermore, there is also the use of short-wavelength radiation such as ArF excimer lasers, and liquid immersion lithography, in which exposure is performed with the space between the lens of the exposure apparatus and the resist film filled with a liquid medium. As next-generation technologies, lithography using even shorter-wavelength radiation such as electron beams, X-rays, and EUV (extreme ultraviolet) is also being considered.

[0004] Regarding photoacid generators, which are the main components of resist compositions, perfluoroalkyl sulfonic acid or its salts, which can impart strong acid, are widely used to improve sensitivity and resolution. On the other hand, in recent years, due to growing environmental awareness, photoacid generators that do not have a perfluoro structure are being investigated (see Japanese Patent Publication No. 5965855).

[0005] Patent No. 5965855

[0006] In developing photoacid generators that do not have a perfluoro structure, the resist composition is required to have performance equivalent to or better than conventional resists in terms of sensitivity, exposure margin, depth of field, pattern rectangularity, storage stability, development defect performance, CDU (Critical Dimension Uniformity), and pattern circularity.

[0007] The present invention aims to provide a radiation-sensitive composition, a pattern forming method, and a compound that can exhibit sufficient levels of sensitivity, exposure latitude, depth of focus, pattern rectangularity, storage stability, development defect performance, CDU, and pattern circularity during resist pattern formation.

[0008] As a result of intensive studies to solve this problem, the present inventors have found that the above object can be achieved by adopting the following configuration, and have completed the present invention.

[0009] That is, in one embodiment, the present invention relates to a radiation-sensitive composition containing a polymer (A), a first radiation-sensitive acid generator (B) represented by the following formula (1), a second radiation-sensitive acid generator (C) that generates a sulfonic acid (excluding those corresponding to the above first radiation-sensitive acid generator (B)), and a solvent (E). (In formula (1), １ X １ is -F, -Br, -I, or -CN. However, when n1 is 1, X １ is -Br, -I, or -CN. When there are a plurality of X １ , the plurality of X １ are each the same or different. n1 is an integer from 1 to 5. However, when there are a plurality of X １ and all of the plurality of X １ R １１ is an alkyl group, -OCOR １２ , -COOR ２ R １３ is or -SO １１ R １２ R １３ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. When there are a plurality of R １ , the plurality of R １ are each the same or different. However, R １ does not contain a polymerizable group. n2 is an integer from 0 to 5. However, n1 + n2 ≦ 5. When at least one of the above X １ is -I or -CN, M １ ＋This is an iodonium cation. (X above) １ However, in the case of -F or -Br, M １ ＋ This is a cation represented by the following formula (a). (In formula (a), Y is a halogen atom, a C2-C4 alkyl group, a C2-C4 alkoxy group, a halogenated alkyl group, -OCOR １４ , or -COOR １５ That is. R １４ , R １５ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. If multiple Y groups exist, they are either identical or distinct. Ar is an aromatic ring. R ２ R is a monovalent organic group. ３ R is a methyl group, hydroxyl group, cyano group, nitro group, or acyl group. ３ If multiple R ３ They are either the same or different. m1 is an integer between 1 and 5. m2 is an integer between 0 and 5.

[0010] The radiation-sensitive composition, by containing a first radiation-sensitive acid generator (B) represented by formula (1) above and a second radiation-sensitive acid generator (C) that generates sulfonic acid, can form a resist film that exhibits sufficient levels of sensitivity, exposure margin, depth of field, pattern rectangularity, storage stability, development defect performance, CDU, and pattern circularity. The reason for this is presumed to be as follows, although it is not bound by any theory.

[0011] The first radiation-sensitive acid generator (B) is strongly acidic due to the presence of specific electron-withdrawing groups on its benzene ring. As a result, the efficiency of acid-catalyzed reactions is increased, improving the dissolution contrast between exposed and unexposed areas, and thus potentially improving various properties such as pattern rectangularity. Furthermore, since the first radiation-sensitive acid generator (B) is an onium salt with an iodonium cation, it is presumed to have an excellent balance of acid generation efficiency, developer solubility, and storage stability, potentially improving various properties such as development defect performance and roughness. Moreover, by using two types of radiation-sensitive acid generators, the first radiation-sensitive acid generator (B) and the second radiation-sensitive acid generator (C), it becomes possible to control the diffusion length of the generated acid, reducing variations in generated acid due to uneven exposure between the upper and lower layers of the pattern, and enabling the development of good roughness performance. It is presumed that the given resist properties can be achieved through the combined action of these factors.

[0012] In another embodiment, the present invention relates to a pattern forming method comprising the steps of: applying the radiation-sensitive composition directly or indirectly to a substrate to form a resist film; exposing the resist film to light; and developing the exposed resist film with a developer.

[0013] This pattern formation method uses the above-mentioned radiation-sensitive composition, which is capable of forming a resist film with excellent sensitivity, exposure margin, depth of field, pattern rectangularity, storage stability, development defect performance, CDU, and pattern circularity, thus enabling the efficient formation of high-quality resist patterns.

[0014] In another embodiment, the present invention relates to a compound represented by the following formula (1'). (In formula (1'), X １１ is -I or -CN. However, X １１ If is -CN and n1 is 1, then X １１ SO ３ - It is located in the meta or ortho position relative to the group. １１ If there are multiple X １１ These are either identical or different. n1 is an integer between 1 and 5. １is an alkyl group, -OCOR １１ ,-COOR １２ , or -SO ２ R １３ That is. R １１ , R １２ , R １３ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. １ If multiple R １ They are either the same or different. However, R １ It does not contain polymerizable groups. n2 is an integer from 0 to 5, where n1 + n2 ≤ 5. M ２ ＋ This is an iodonium cation.

[0015] By using a radiation-sensitive composition containing the compound, it is possible to form a resist film that is excellent in sensitivity, exposure margin, depth of field, pattern rectangularity, storage stability, development defect performance, CDU, and pattern circularity.

[0016] The embodiments of the present invention will be described in detail below, but the present invention is not limited to these embodiments. A preferred combination of embodiments is also preferable.

[0017] <<Radiation-sensitive composition>> The radiation-sensitive composition according to this embodiment (hereinafter also simply referred to as "the composition") contains a polymer (A), a first radiation-sensitive acid generator (B) represented by the above formula (1), a second radiation-sensitive acid generator (C) that generates sulfonic acid (excluding those corresponding to the first radiation-sensitive acid generator (B)), and a solvent (E). The components included in the composition of the present invention will be described below.

[0018] <Primary Radiation-Reactive Acid Generator (B)> The primary radiation-reactive acid generator (B), represented by the following formula (1), generates acid upon exposure. (In formula (1), X １ is -F, -Br, -I, or -CN. However, if n1 is 1, then X １ is -Br, -I, or -CN. X １ If there are multiple X １They are either the same or different. n1 is an integer from 1 to 5. However, X １ There are multiple X １ If all values ​​are -F, then n1 is an integer between 3 and 5. １ is an alkyl group, -OCOR １１ ,-COOR １２ , or -SO ２ R １３ That is. R １１ , R １２ , R １３ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. １ If multiple R １ They are either the same or different. However, R １ It does not contain polymerizable groups. n2 is an integer from 0 to 5, where n1 + n2 ≤ 5. The above X １ If at least one of them is -I or -CN, then M １ ＋ This is an iodonium cation. (X above) １ However, in the case of -F or -Br, M １ ＋ This is a cation represented by the following formula (a). (In formula (a), Y is a halogen atom, a C2-C4 alkyl group, a C2-C4 alkoxy group, a halogenated alkyl group, -OCOR １４ , or -COOR １５ That is. R １４ , R １５ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. If multiple Y groups exist, they are either identical or distinct. Ar is an aromatic ring. R ２ R is a monovalent organic group. ３ R is a methyl group, hydroxyl group, cyano group, nitro group, or acyl group. ３ If multiple R ３ They are either the same or different. m1 is an integer between 1 and 5. m2 is an integer between 0 and 5.

[0019] n1 is an integer from 1 to 5, and is preferably an integer from 3 to 5 from the viewpoint of increasing the acidity of the generated acid.

[0020] Among them X １ -F is preferred, n1 is 5, and there are 5 X １ It is even more preferable that all of them are -F.

[0021] If n1 is 1, X １ The compound is -Br, -I, or -CN, and -I or -CN is preferred from the viewpoint of increasing the acidity of the generated acid and from the viewpoint of developer solubility.

[0022] R １ Examples of alkyl groups represented by this symbol include alkyl groups having 1 to 20 carbon atoms, such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, n-pentyl group, isopentyl group, and neopentyl group.

[0023] R １１ , R １２ , R １３ Examples of monovalent organic groups having 1 to 20 carbon atoms represented by this formula include monovalent hydrocarbon groups having 1 to 20 carbon atoms, groups having a divalent heteroatom-containing group between carbon atoms or at the end of the carbon chain of this hydrocarbon group, groups in which some or all of the hydrogen atoms of the hydrocarbon group are replaced with a monovalent heteroatom-containing group, or combinations thereof.

[0024] Examples of the above-mentioned monovalent hydrocarbon groups having 1 to 20 carbon atoms include chain-like hydrocarbon groups having 1 to 20 carbon atoms, monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, and monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms.

[0025] Examples of the above-mentioned monovalent linear hydrocarbon groups having 1 to 20 carbon atoms include monovalent linear or branched saturated hydrocarbon groups having 1 to 20 carbon atoms, or monovalent linear or branched unsaturated hydrocarbon groups having 2 to 20 carbon atoms. Examples of the above-mentioned monovalent linear or branched saturated hydrocarbon groups having 1 to 20 carbon atoms include alkyl groups such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, n-pentyl group, isopentyl group, and neopentyl group. Examples of the above-mentioned monovalent linear or branched unsaturated hydrocarbon groups having 2 to 20 carbon atoms include alkenyl groups such as ethenyl group, propenyl group, and butenyl group; and alkynyl groups such as ethynyl group, propynyl group, and butynyl group.

[0026] Examples of monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms include monocyclic or polycyclic saturated hydrocarbon groups, or monocyclic or polycyclic unsaturated hydrocarbon groups. Examples of monocyclic saturated hydrocarbon groups include cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. Examples of polycyclic saturated hydrocarbon groups include bridged alicyclic hydrocarbon groups such as norbornyl, adamantyl, tricyclodecyl, and tetracyclododecyl groups. Examples of monocyclic unsaturated hydrocarbon groups include monocyclic cycloalkenyl groups such as cyclopropenyl, cyclobutenyl, cyclopentenyl, and cyclohexenyl groups. Examples of polycyclic unsaturated hydrocarbon groups include polycyclic cycloalkenyl groups such as norborneyl, tricyclodecenyl, and tetracyclododecenyl groups. A bridged alicyclic hydrocarbon group is a polycyclic alicyclic hydrocarbon group in which two carbon atoms that are not adjacent to each other are bonded together by a linking group containing one or more carbon atoms.

[0027] Examples of the monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms include aryl groups such as phenyl, tolyl, xyl, naphthyl, and anthyl groups; and aralkyl groups such as benzyl, phenethyl, and naphthylmethyl groups.

[0028] Examples of the heteroatom constituting the monovalent heteroatom-containing group or the divalent heteroatom-containing group include an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a silicon atom, a halogen atom, etc. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0029] Examples of the monovalent heteroatom-containing group include a hydroxy group, a carboxy group, a sulfanyl group, a cyano group, a nitro group, a halogen atom, etc.

[0030] Examples of the divalent heteroatom-containing group include -CO-, -C(=O)O-, -CS-, -NH-, -O-, -S-, -SO-, -SO ２ -, or a group formed by combining these.

[0031] The above R １１ is preferably a monovalent organic group having 1 to 20 carbon atoms and having 2 or less iodine atoms, more preferably a monovalent organic group having 1 to 20 carbon atoms and not containing an iodine atom, and still more preferably a monovalent organic group having 1 to 10 carbon atoms and not containing an iodine atom.

[0032] Among these, the above R １１ , R １２ , R １３ , R １４ are preferably a chain hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a combination thereof, more preferably a chain hydrocarbon group having 1 to 5 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, or a phenyl group, and still more preferably a chain hydrocarbon group having 1 to 4 carbon atoms or an alicyclic hydrocarbon group having 3 to 6 carbon atoms from the viewpoints of developing solution solubility and acid diffusion control.

[0033] The above R １ is preferably -OCOR １１ , -COOR １２ or -SO ２ R １３ , more preferably -OCOR １１ or -SO ２ R １３ .

[0034] n2 is an integer between 0 and 5, preferably 0 or 1.

[0035] Specific examples of the anion of the primary radioactive acid generator (B) represented by the above formula (1) include, but are not limited to, the structure shown in the following formula.

[0036]

[0037]

[0038]

[0039]

[0040] The above X １ If at least one of them is -I or -CN, then M １ ＋ This is an iodonium cation. As the iodonium cation, for example, the iodonium cation represented by the following formula (b) is preferred.

[0041] (In formula (b), R Ａ１ and R Ａ２ Each of these is independently a monovalent organic group having 1 to 10 carbon atoms, or R Ａ１ and R Ａ２ (This represents a ring structure with 3 to 20 members, formed by combining these elements with the iodine atoms to which they bond.)

[0042] R Ａ１ and R Ａ２ As a monovalent organic group having 1 to 10 carbon atoms represented by the above R １１ , R １２ , R １３ Among the monovalent organic groups having 1 to 20 carbon atoms represented by , those with the corresponding number of carbon atoms can be suitably adopted. Among these, substituted or unsubstituted monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms are preferred, substituted or unsubstituted phenyl groups are more preferred, and substituted phenyl groups are even more preferred.

[0043] When the above aromatic hydrocarbon group has substituents, examples of substituents include halogen atoms such as fluorine, chlorine, bromine, and iodine atoms; hydroxyl groups; carboxyl groups; cyano groups; nitro groups; amino groups; alkyl groups; alkoxy groups; alkoxycarbonyl groups; alkoxycarbonyloxy groups; acyl groups; acyloxy groups or groups in which the hydrogen atoms of these groups are substituted with halogen atoms; and substituents (T) such as oxo groups (=O).

[0044] The alkyl group as the substituent (T) is R. １ Alkyl groups represented by can be suitably adopted. Examples of alkoxy groups include linear or branched alkoxy groups having 1 to 8 carbon atoms, such as methoxy, ethoxy, and propoxy groups. Examples of alkoxycarbonyl groups include alkoxycarbonyl groups having 1 to 6 carbon atoms, such as methoxycarbonyl and ethoxycarbonyl groups. Examples of alkoxycarbonyloxy groups include linear or alicyclic alkoxycarbonyloxy groups having 2 to 16 carbon atoms, such as methoxycarbonyloxy, butoxycarbonyloxy, and adamantylmethyloxycarbonyloxy groups. Examples of acyl groups include aliphatic or aromatic acyl groups having 2 to 12 carbon atoms, such as acetyl, propionyl, benzoyl, and acryloyl groups. Examples of acyloxy groups include aliphatic or aromatic acyloxy groups having 2 to 12 carbon atoms, such as acetyloxy, propionyloxy, benzoyloxy, and acryloyloxy groups.

[0045] Among the substituents (T) above, from the viewpoint of storage stability, pattern formation, and development defect performance, the substituent represented by Y above (halogen atom, C2-C4 alkyl group, C2-C4 alkoxy group, alkyl halide, -OCOR) １４ , or -COOR １５ ) is preferred. Among these, fluorine atoms, iodine atoms, ethyl groups, i-propyl groups, t-butyl groups, and butoxy groups are preferred as substituents (T).

[0046] Specific examples of the iodonium cation of the first radioactive acid generator (B) represented by the above formula (1) include, but are not limited to, the structure shown in the following formula.

[0047]

[0048]

[0049]

[0050]

[0051] The above X １ However, in the case of -F or -Br, M １ ＋ This is a cation represented by the following formula (a). (In formula (a), Y is a halogen atom, a C2-C4 alkyl group, a C2-C4 alkoxy group, a halogenated alkyl group, -OCOR １４ , or -COOR １５ That is. R １４ , R １５ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. If multiple Y groups exist, they are either identical or distinct. Ar is an aromatic ring. R ２ R is a monovalent organic group. ３ R is a methyl group, hydroxyl group, cyano group, nitro group, or acyl group. ３ If multiple R ３ They are either the same or different. m1 is an integer between 1 and 5. m2 is an integer between 0 and 5.

[0052] Examples of halogen atoms represented by Y above include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, with fluorine atoms and iodine atoms being preferred among these.

[0053] Examples of C2-C4 alkyl groups represented by Y include ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, and t-butyl group. Examples of C2-C4 alkoxy groups represented by Y include ethoxy group, propoxy group, and butoxy group. Among these, ethyl group, i-propyl group, t-butyl group, and butoxy group are preferred.

[0054] The above halogenated alkyl group is R １ Examples include groups in which one or more hydrogen atoms of an alkyl group represented by are substituted with halogen atoms.

[0055] R １４ , R １５ As a monovalent organic group having 1 to 20 carbon atoms represented by the above R １１ , R １２ , R １３ A monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably used.

[0056] Among these, Y includes halogen atoms, C2-C4 alkyl groups, C2-C4 alkoxy groups, C2-C4 alkyl halides, and -OCOR １６ , or -COOR １７ (R １６ , R １７ Each of these is preferably a hydrogen atom or a monovalent organic group having 2 to 4 carbon atoms.

[0057] The aromatic ring represented by Ar above is not particularly limited as long as it has an aromatic ring structure. Examples of aromatic rings include aromatic hydrocarbon rings such as benzene rings, naphthalene rings, anthracene rings, phenalene rings, phenanthrene rings, pyrene rings, fluorene rings, perylene rings, and coronene rings; aromatic heterocycles such as furan rings, pyrrole rings, thiophene rings, phosphole rings, pyrazole rings, oxazole rings, isoxazole rings, thiazole rings, pyridine rings, pyrazine rings, pyrimidine rings, pyridazine rings, triazine rings, carbazole rings, and dibenzofuran rings; or combinations thereof. Among these, aromatic hydrocarbon rings are preferred, benzene rings and naphthalene rings are more preferred, and benzene rings are even more preferred.

[0058] The above R ２ The monovalent organic group represented by the above R is １１ , R １２ , R １３ A monovalent organic group having 1 to 20 carbon atoms, represented by the formula above, can be suitably used. Among these, the above R ２ Preferably, the group is represented by the following formula (i). (In formula (i), X ２ This includes halogen atoms, C2-C4 alkyl groups, C2-C4 alkoxy groups, alkyl halides, and -OCOR ２１ , or -COOR ２２ That is. R ２１ , R ２２ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. a is 0 or 1. b is an integer from 0 to (2a + 5). * represents the bond with iodine in formula (a).

[0059] As the C2-C4 alkyl group, C2-C4 alkoxy group, and halogenated alkyl group mentioned above, the C2-C4 alkyl group, C2-C4 alkoxy group, and halogenated alkyl group in formula (a) above can be suitably adopted.

[0060] The above R ２１ , R ２２ As a monovalent organic group having 1 to 20 carbon atoms, the above R １１ , R １２ , R １３ A monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably used.

[0061] 'a' is preferably 0.

[0062] b is preferably 1 to 3.

[0063] Examples of the group represented by (i) above include the following groups. (In the formula, * is equivalent to formula (i) above.)

[0064] The above R ３Examples of acyl groups represented by this symbol include aliphatic or aromatic acyl groups having 2 to 12 carbon atoms, such as acetyl groups, propionyl groups, benzoyl groups, and acryloyl groups.

[0065] m1 is an integer from 1 to 5, and is preferably 1 or 2.

[0066] m2 is an integer between 0 and 5, preferably 0 or 1.

[0067] As specific examples of the cation represented by formula (a) above, those corresponding to the specific examples of iodonium cations above can be suitably adopted.

[0068] As a specific example of the first radioactive acid generator (B) represented by formula (1) above, a structure in which the above anion and cation are appropriately combined can be adopted, for example, the structure shown in the following formula.

[0069]

[0070]

[0071]

[0072]

[0073]

[0074] The above-mentioned radiation-sensitive composition may contain one or more types of the first radiation-sensitive acid generator (B).

[0075] The lower limit of the content of the first radioactive acid generator (B) described above (total amount if multiple types are included) is preferably 0.1 parts by mass, more preferably 0.5 parts by mass, and still more preferably 1 part by mass, per 100 parts by mass of the polymer (A) described later. The upper limit of the above content ratio is preferably 70 parts by mass, more preferably 60 parts by mass, and still more preferably 50 parts by mass. By setting the content of the first radioactive acid generator (B) within the above range, excellent sensitivity can be achieved when forming a resist pattern.

[0076] <Secondary Radiation-Sensitive Acid Generator (C)> The above-mentioned radiation-sensitive composition contains, together with the above-mentioned first radiation-sensitive acid generator (C), a second radiation-sensitive acid generator (C) that generates sulfonic acid (excluding those corresponding to the above-mentioned first radiation-sensitive acid generator (B)).

[0077] The above-mentioned second radioactive acid generator (C) is preferably a compound containing at least one cyclic structure.

[0078] The above cyclic structure may be an alicyclic structure, an aromatic cyclic structure, or a heterocyclic structure, and may be a monocyclic or polycyclic structure, and may be saturated or unsaturated. Furthermore, it may be formed solely of cyclic structures, or it may have a chain-like structure in part. If it has a chain-like structure in part, heteroatoms such as O and S may be included between the carbon-carbon bonds in the chain-like structure. As an alicyclic structure, R in formula (1) above... １１ , R １２ , R １３ Examples of structures corresponding to monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms can be given. In addition, as an aromatic ring structure, R in formula (1) above can be cited. １１ , R １２ , R １３ Examples of structures corresponding to monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms can be given. The heterocyclic structure is not particularly limited and includes lactone structures, cyclic carbonate structures, cyclic acetal structures, cyclic ether structures, sultone structures, cyclic amine structures, etc.

[0079] The above-mentioned secondary radioactive acid generator (C) is not particularly limited as long as it does not fall under formula (1) above and generates sulfonic acid, but it is preferable that it is a compound represented by, for example, formula (2) below (hereinafter also referred to as "secondary radioactive acid generator (C2)"), formula (3) below (hereinafter also referred to as "secondary radioactive acid generator (C3)"), or formula (4) below (hereinafter also referred to as "secondary radioactive acid generator (C4)").

[0080] (Secondary radioactive acid generator (C2)) The secondary radioactive acid generator (C2) is represented by the following formula (2). (In formula (2), R４ Z is a monovalent organic group having 1 to 40 carbon atoms. ２ ＋ (This is a monovalent organic cation.)

[0081] The above R ４ As a monovalent organic group having 1 to 40 carbon atoms represented by the above formula (1), R １１ , R １２ , R １３ A monovalent organic group with 1 to 20 carbon atoms represented by can be preferably used, with the carbon number extended to 1 to 40. ４ In a monovalent organic group having 1 to 40 carbon atoms represented by SO ３ - From the viewpoint of controlling the diffusion length of the generated acid, it is preferable that no fluorine atoms or fluorinated hydrocarbon groups are bonded to atoms adjacent to the sulfur atoms in the acid.

[0082] The above R ４ As such, it includes at least one cyclic structure, and SO ３ - It is preferable that the organic group is a monovalent organic group having 3 to 40 carbon atoms, in which no fluorine atom or fluorinated hydrocarbon group is bonded to any atom adjacent to the sulfur atom. ３ - It is preferable from the viewpoint of controlling the diffusion length of the generated acid that the benzene ring structure is not directly bonded to the sulfur atom inside. That is, R ４ SO ３ - It is preferable that the side terminals do not have a benzene ring.

[0083] The above fluorinated hydrocarbon group is R of formula (1) above. １１ , R １２ , R １３ Examples include groups in which some or all of the hydrogen atoms of a monovalent hydrocarbon group having 1 to 20 carbon atoms are replaced with fluorine atoms.

[0084] Specific examples of the anion of the secondary radioactive acid generator (C2) include, but are not limited to, the structure shown in the following formula.

[0085]

[0086]

[0087]

[0088]

[0089] The above Z of the second radioactive acid generator (C2) ２ ＋ The onium cation represented by is preferably a radiation-sensitive onium cation, for example, a radiation-sensitive onium cation containing elements such as S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, and Bi. Examples of radiation-sensitive onium cations include sulfonium cations, tetrahydrothiophenium cations, iodonium cations, phosphonium cations, diazonium cations, and pyridinium cations. Among these, sulfonium cations or iodonium cations are preferred.

[0090] As the iodonium cation, the iodonium cation represented by formula (b) above can be suitably used.

[0091] Examples of sulfonium cations include those represented by the following formulas (X-1) to (X-4).

[0092]

[0093] In the above equation (X-1), R ａ１ , R ａ２ and R ａ３ Each of these independently comprises a substituted or unsubstituted linear or branched alkyl group, alkoxy group or alkoxycarbonyloxy group having 1 to 12 carbon atoms, a substituted or unsubstituted monocyclic or polycyclic cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, hydroxyl group, halogen atom, or -OSO ２ -R Ｐ , -SO ２ -R Ｑ , -S-R ＴR represents a ring structure consisting of -O-, -CO-, or a combination thereof, or two or more of these groups combined with each other. This ring structure may contain heteroatoms such as O or S between the carbon-carbon bonds forming the skeleton. Ｐ , R Ｑ and R Ｔ Each of these is independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k1, k2, and k3 are each independently integers from 0 to 5. R ａ１ ~R ａ３ And R Ｐ , R Ｑ and R Ｔ If each of them is multiple, then multiple R ａ１ ~R ａ３ And R Ｐ , R Ｑ and R Ｔ These may be the same or different.

[0094] In the above equation (X-2), R ｂ１ This is a substituted or unsubstituted linear or branched alkyl or alkoxy group having 1 to 20 carbon atoms, an alkoxyalkyloxy group, a substituted or unsubstituted acyl group having 2 to 8 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms, or a hydroxyl group. ｋ n is either 0 or 1. ｋ When is 0, k4 is an integer from 0 to 4, and n ｋ When k4 is 1, k4 is an integer from 0 to 7. ｂ１ If there are multiple R ｂ１ They may be the same or different, and there may be multiple R's. ｂ１ R may represent a ring structure formed by combining with other elements. ｂ２ This is a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. Ｃ k5 is a single bond or a divalent linking group. k5 is an integer from 0 to 4. ｂ２ If there are multiple R ｂ２They may be the same or different, and there may be multiple R's. ｂ２ may represent a ring structure formed by combining with each other. q is an integer from 0 to 3. In the formula, S ＋ The ring structure containing may include heteroatoms such as O and S between the carbon-carbon bonds that form the skeleton.

[0095] In the above equation (X-3), R ｃ１ , R ｃ２ and R ｃ３ Each of these is independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms.

[0096] In the above equation (X-4), R ｇ１ This is a substituted or unsubstituted linear or branched alkyl or alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted acyl group having 2 to 8 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms, or a hydroxyl group. ｋ２ n is either 0 or 1. ｋ２ When is 0, k10 is an integer from 0 to 4, and n ｋ２ When is 1, k10 is an integer from 0 to 7. ｇ１ If there are multiple R ｇ１ They may be the same or different, and there may be multiple R's. ｇ１ R may represent a ring structure formed by combining with other elements. ｇ２ and R ｇ３ Each of these independently represents a substituted or unsubstituted linear or branched alkyl group, alkoxy group or alkoxycarbonyloxy group having 1 to 12 carbon atoms, a substituted or unsubstituted monocyclic or polycyclic cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, hydroxyl group, halogen atom having 6 to 12 carbon atoms, or a ring structure formed by combining these groups. k11 and k12 are each independently integers from 0 to 4. R ｇ２ and R ｇ３ If each of them is multiple, then multiple R ｇ２ and R ｇ３ These may be the same or different.

[0097] Specific examples of the above sulfonium cation include, but are not limited to, the structure shown in the following formula.

[0098] (In the formula, tBu represents a t-butyl group and Me represents a methyl group.)

[0099]

[0100]

[0101]

[0102] The second radioactive acid generator (C2) can be obtained by appropriately combining the above-mentioned anion and the above-mentioned radioactive onium cation.

[0103] The above-mentioned secondary radioactive acid generator (C2) can also be synthesized by known methods, particularly by salt exchange reactions.

[0104] (Secondary radioactive acid generator (C3)) The secondary radioactive acid generator (C3) is represented by the following formula (3). (In formula (3), R ５ R is a monovalent organic group having 1 to 40 carbon atoms. ６ If multiple R groups exist, each independently consists of a hydrogen atom, a nitro group, a hydroxyl group, a cyano group, a carboxyl group, a thiol group, a halogen atom, or a monovalent organic group, or two R groups. ６ These are divalent cyclic groups with 3 to 20 carbon atoms, formed by combining them with the carbon atoms to which they are bonded. t is an integer from 0 to 20. W represents a ring structure with 5 to 8 members formed together with the carbon and nitrogen atoms to which it is bonded.

[0105] The above R ５ As a monovalent organic group having 1 to 40 carbon atoms represented by the above formula (1), R １１ , R １２ , R １３ A monovalent organic group with 1 to 20 carbon atoms represented by can be preferably used, with the carbon number extended to 1 to 40. ５ In a monovalent organic group having 1 to 40 carbon atoms represented by SO ３ -It is preferable that no fluorine atom or fluorinated hydrocarbon group is bonded to an atom adjacent to the sulfur atom in the middle. Among these, R ５ Preferably, it is a group containing an alicyclic structure. The alicyclic structure is R in formula (1) above. １１ , R １２ , R １３ Structures corresponding to monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms can be cited.

[0106] The above fluorinated hydrocarbon group is R of formula (1) above. １１ , R １２ , R １３ Examples include groups in which some or all of the hydrogen atoms of a monovalent hydrocarbon group having 1 to 20 carbon atoms are replaced with fluorine atoms.

[0107] The above R ６ The monovalent organic group represented by is R in formula (1) above. １１ , R １２ , R １３ A monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably used.

[0108] Two R's ６ When these are combined with each other, the divalent cyclic group having 3 to 20 carbon atoms that is formed together with the carbon atoms to which they are bonded is R in formula (1) above. １１ , R １２ , R １３ Examples include monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, and monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms from which one hydrogen atom has been removed.

[0109] t is an integer between 0 and 20, preferably between 0 and 10, and more preferably 0 or 1.

[0110] W represents a ring structure with 5 to 8 members formed together with the carbon and nitrogen atoms to which it is bonded, such as succinimide and glutarimide structures.

[0111] The following structure is a specific example of a secondary radioactive acid generator (C3).

[0112]

[0113] (Secondary radioactive acid generator (C4)) The secondary radioactive acid generator (C4) is represented by the following formula (4). (In formula (4), R ７ These are, independently, monovalent organic groups having 1 to 20 carbon atoms.

[0114] The above R ７ As a monovalent organic group having 1 to 20 carbon atoms represented by the above formula (1), R １１ , R １２ , R １３ A monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably used.

[0115] The following structure is a specific example of a secondary radioactive acid generator (C4).

[0116]

[0117] The above-mentioned radiation-sensitive composition may contain one or more secondary radiation-sensitive acid generators (C).

[0118] The lower limit of the content of the above-mentioned secondary radioactive acid generator (C) (total amount if multiple types are included) is preferably 0.1 parts by mass, more preferably 0.5 parts by mass, and still more preferably 1 part by mass, per 100 parts by mass of the polymer (A) described later. The upper limit of the above-mentioned content ratio is preferably 70 parts by mass, more preferably 60 parts by mass, and still more preferably 50 parts by mass. By setting the content of the secondary radioactive acid generator (C) within the above range, excellent sensitivity can be achieved when forming a resist pattern.

[0119] <Polymer (A)> The polymer (A) described above is not particularly limited, but it is preferably an aggregate of polymerization chains containing structural unit (I) having a phenolic hydroxyl group (hereinafter this polymer will also be referred to as "base polymer (A)").

[0120] Examples of polymers (A) containing a structural unit (I) having a phenolic hydroxyl group include polymers (A-1) containing a structural unit (I-1) represented by formula (5) described later, or novolac polymers (A-2) containing a structural unit (I-2) represented by formula (10) described later.

[0121] (Polymer (A-1)) The base polymer (A-1) preferably contains structural unit (I-1), and may also contain other structural units besides structural unit (I-1). Each structural unit is described below.

[0122] [Structural Unit (I-1)] The polymer (A-1) preferably contains structural unit (I-1) having a phenolic hydroxyl group. The structural unit (I-1) is preferably represented by the following formula (5).

[0123] (In the above formula (5), R Ａ L is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. ＣＡ This is a single bond, -COO- ＊ Or -O-. * indicates a bond on the aromatic ring side. X is a halogen atom, cyano group, nitro group, alkyl group, alkoxy group, carboxy group, fluorinated alkyl group, alkoxycarbonyl group, acyl group, or acyloxy group. If multiple Xs exist, they are either identical or distinct from one another. p is an integer from 0 to 2, n is an integer from 1 to 8, and m is an integer from 0 to 8, satisfying 1 ≤ n + m ≤ 2p + 5.

[0124] The above R Ａ Preferably, it is a hydrogen atom or a methyl group.

[0125] L ＣＡ For example, a single bond or -COO- ＊ It is preferable.

[0126] The alkyl group in X is R in formula (1) above. １ The alkyl group in can be suitably adopted. The alkyl group portion of the alkoxy group and the alkyl group portion of the alkoxycarbonyl group in X are R in formula (1) above. １ The alkyl group in can be suitably adopted. As the fluorinated alkyl group in X, a group in which some or all of the hydrogen atoms of the above alkyl group are substituted with fluorine atoms can be suitably adopted. As the acyl group in X, R of formula (a) above can be adopted. ３ The acyl group represented by can be suitably adopted.

[0127] Examples of acyloxy groups in X include aliphatic or aromatic acyloxy groups having 2 to 12 carbon atoms, such as acetyloxy groups, propionyloxy groups, benzoyloxy groups, and acryloyloxy groups.

[0128] Among these, halogen atoms are preferred for X, and iodine atoms and fluorine atoms are more preferred.

[0129] The above value of p is preferably 0 or 1, with 0 being preferred.

[0130] The above n is preferably an integer from 1 to 3, and more preferably 1 or 2.

[0131] For the above value m, an integer between 0 and 3 is preferred, and an integer between 0 and 2 is more preferred.

[0132] The above structural unit (I-1) is more preferably a structural unit represented by the following formula (5-1). (In equation (5-1), q1 is an integer between 1 and 5. q2 is an integer between 0 and 4. However, q1 + q2 is less than or equal to 5. R Ａ X is equivalent to equation (5) above.

[0133] The above q1 is preferably an integer from 1 to 3, and more preferably 1 or 2.

[0134] For q2, an integer between 0 and 3 is preferred, and an integer between 0 and 2 is more preferred.

[0135] The above structural unit (I-1) is preferably a structural unit represented by the following formula. In the following formula, R Ａ This is the same as equation (5) above.

[0136]

[0137] The base polymer (A-1) may contain one or more structural units (I-1) in combination.

[0138] The lower limit of the content of the above structural unit (I-1) (total if there are multiple types of structural unit (I-1)) is preferably 10 mol%, more preferably 20 mol%, and even more preferably 30 mol%, relative to the total structural units constituting the polymer (A-1). The upper limit of the above content is preferably 100 mol%, more preferably 95 mol%, and even more preferably 90 mol%. By setting the content of structural unit (I-1) within the above range, the radiation-sensitive composition can be made to further improve its sensitivity.

[0139] Furthermore, if the above-mentioned radiation-sensitive composition is a negative-type radiation-sensitive composition, the lower limit of the content ratio of the above-mentioned structural unit (I-1) (total if there are multiple types of structural unit (I-1)) is preferably 20 mol%, more preferably 30 mol%, and even more preferably 40 mol%, relative to the total structural units constituting the polymer (A-1). The upper limit of the above-mentioned content ratio is preferably 100 mol%, more preferably 95 mol%, and even more preferably 90 mol%.

[0140] Furthermore, if the radiation-sensitive composition is a positive-type radiation-sensitive composition, the lower limit of the content ratio of the structural unit (I-1) (total if there are multiple types of structural unit (I-1)) is preferably 20 mol%, more preferably 30 mol%, and even more preferably 40 mol%, relative to the total structural units constituting the polymer (A-1). The upper limit of the content ratio is preferably 70 mol%, more preferably 60 mol%, and even more preferably 50 mol%. By setting the content ratio of structural unit (I-1) within the above range, the radiation-sensitive composition can achieve further improvement in sensitivity.

[0141] [Structural Unit (II)] From the viewpoint of etching resistance, it is preferable that polymer (A-1) contains structural unit (II) having an aromatic ring (excluding those corresponding to structural unit (I-1) above).

[0142] The structural unit (II) described above is preferably the structural unit represented by the following formula (6).

[0143] (In the above formula (6), R Ａ L is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.ＣＡ This is a single bond, -COO- ＊ Or -O-. * indicates a bond on the aromatic ring side. X １ X is a halogen atom, cyano group, nitro group, alkyl group, alkoxy group, carboxy group, fluorinated alkyl group, alkoxycarbonyl group, acyl group, or acyloxy group. １ If there are multiple X １ They are either identical or different. q3 is an integer between 0 and 2, and q4 is an integer between 0 and 8.

[0144] The above R A Preferably, it is a hydrogen atom or a methyl group.

[0145] The above L ＣＡ For example, a single bond or -COO- ＊ A single bond is preferred, and a single bond is even more preferred.

[0146] X １ In this, the alkyl group, alkoxy group, fluorinated alkyl group, alkoxycarbonyl group, acyl group, and acyloxy group listed as X in formula (5) above can be suitably adopted. Among these, X １ A alkyl group or a carboxyl group is preferred as the group.

[0147] For q3, 0 or 1 is preferred, with 0 being preferred.

[0148] For q4, an integer between 0 and 3 is preferred, and 0 or 1 is more preferred.

[0149] The above structural unit (II) is preferably a structural unit represented by the following formula. In the following formula, R Ａ This is the same as equation (6) above.

[0150]

[0151] The base polymer (A-1) may contain one or more structural units (II) in combination.

[0152] When the base polymer (A-1) contains the structural unit (II), the lower limit of the content of the structural unit (II) (total if there are multiple types of structural unit (II)) is preferably 1 mol%, more preferably 3 mol%, and even more preferably 5 mol%, relative to the total structural units constituting the polymer (A-1). The upper limit of the content is preferably 60 mol%, more preferably 50 mol%, and even more preferably 40 mol%. By setting the content of structural unit (II) within the above range, the radiation-sensitive composition can be made to further improve etching resistance and sensitivity.

[0153] [Structural Unit (III)] When the above-mentioned radiation-sensitive composition is a positive-type radiation-sensitive composition, it is preferable that it contains a structural unit (III) having an acid-dissociable group. An "acid-dissociable group" is a group that substitutes a hydrogen atom, such as a carboxyl group, a phenolic hydroxyl group, an alcoholic hydroxyl group, or a sulfo group, and dissociates due to the action of an acid. The acid generated from the first radiation-sensitive acid generator (B) or the second radiation-sensitive acid generator (C) by exposure dissociates the acid-dissociable group in structural unit (III), generating a carboxyl group, etc. This creates a difference in solubility in the developer between the exposed and unexposed parts of the resist film, enabling pattern formation. In this specification, "dissociation" of an acid-dissociable group means dissociation when post-exposure baking is performed at 110°C for 60 seconds.

[0154] The structural unit (III) is not particularly limited as long as it has an acid-dissociable group, and examples include a structural unit having a tertiary alkyl ester moiety, a structural unit having a structure in which the hydrogen atom of the phenolic hydroxyl group is replaced by a tertiary alkyl group, and a structural unit having an acetal bond. From the viewpoint of improving the pattern-forming properties of the radiation-sensitive composition, the structural unit represented by the following formula (iii) (hereinafter also referred to as "structural unit (III-1)") is preferred.

[0155] (In formula (iii), R １７ R is a hydrogen atom, a fluorine atom, or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. １８R is a monovalent substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms. １９ and R ２０ Each of these independently represents a substituted or unsubstituted monovalent linear hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a divalent alicyclic group having 3 to 20 carbon atoms formed by combining these groups with the carbon atoms to which they are bonded. １１ teeth, ＊ -COO-, ＊ -L １１ａ -COO-, ＊ -L １１ａ -O-, or ＊ -COOL-L １１ａ Represents -COO-. １１ａ * is a substituted or unsubstituted alkanediyl group or arenediyl group. １７ This is the bonding site with the carbon atom to which it is bonded.

[0156] R １７ Examples of C1-C6 alkyl groups represented by include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, n-pentyl group, isopentyl group, neopentyl group, and the like.

[0157] R １７ When an alkyl group having 1 to 6 carbon atoms, represented by [the formula shown], has substituents, examples of substituents include the substituent (T) mentioned above.

[0158] The above R １７ From the viewpoint of copolymerizability of the monomer that gives structural unit (III-1), hydrogen atoms and methyl groups are preferred.

[0159] L １１ａ Examples of alkanediyl groups represented by include divalent alkanediyl groups having 1 to 10 carbon atoms, such as methylene groups, ethanediyl groups, and propanediyl groups. １１ａ The alkanediyl group represented is preferably a methylene group or an ethanediyl group.

[0160] L １１ａExamples of the arenediyl group represented by [the formula] include divalent aromatic hydrocarbon groups having 6 to 20 carbon atoms such as a benzenediyl group and a naphthalenediyl group. L １１ａ As the arenediyl group represented by [the formula], a benzenediyl group is preferred.

[0161] L １１ａ When the alkane diyl group or arenediyl group represented by [the formula] is substituted, substituents such as those described for R １７ can be preferably employed. Among them, as the substituent of L １１ａ , a hydroxy group is preferred.

[0162] L １１ is ＊ -COO-, ＊ -L １１ａ -COO-, ＊ -L １１ａ -O- is preferred.

[0163] Regarding the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the above R １８ , the monovalent hydrocarbon group having 1 to 20 carbon atoms in R １１ , R １２ , R １３ in the above formula (1) can be preferably employed.

[0164] As the above R １８ , an alkyl group having 1 to 10 carbon atoms is preferred.

[0165] Regarding the monovalent chain hydrocarbon group having 1 to 10 carbon atoms represented by R １９ and R ２０ , among the monovalent chain hydrocarbon groups having 1 to 20 carbon atoms in R １１ , R １２ , R １３ in the above formula (1), groups having the corresponding number of carbon atoms can be preferably employed.

[0166] Regarding the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R １９ and R ２０ , the monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms in R １１ , R １２ , R １３ in the above formula (1) can be preferably employed.

[0167] The above R １９ and R ２０ The divalent alicyclic group having 3 to 20 carbon atoms formed by combining the above R and the carbon atom to which they are bonded together includes a group obtained by removing one hydrogen atom from the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms.

[0168] The above R １８ to R ２０ As the substituents that R １７ may have, the substituents shown in R

[0169] Among these, R １８ is preferably an alkyl group having 1 to 4 carbon atoms. R １９ and R ２０ are each independently a methyl group or an ethyl group, or preferably a cycloalkane structure formed by combining them together with the carbon atom to which they are bonded.

[0170] As the structural unit (III-1), for example, structural units represented by the following formulas (iii-1) to (iii-11) (hereinafter, also referred to as "structural units (III-1-1) to (III-1-11)") and the like can be mentioned.

[0171]

[0172] In the above formulas (iii-1) to (iii-11), R １７ to R ２０ have the same meaning as in the above formula (iii). R Ｌ１１ is a halogen atom; a hydroxy group; a carboxy group; a cyano group; a nitro group; an amino group; an alkoxy group; an alkoxycarbonyl group; an alkoxycarbonyloxy group; an acyl group; an acyloxy group or a group in which a hydrogen atom of these groups is substituted with a halogen atom. h, i and j are each independently an integer of 1 to 4. k1, k2 and k3 are each independently 0 or 1. 3a is each independently an integer of 0 to 3. When 3a is 2 or more, the plurality of R Ｌ１１ are the same as or different from each other.

[0173] As h, i and j, 1 or 2 is preferable. R １８Preferred groups include methyl, ethyl, isopropyl, ethenyl (vinyl), butenyl, phenyl, and iodophenyl groups. １９ and R ２０ Preferably, the group is a methyl group, an ethyl group, or an isopropyl group. Ｌ１１ Preferred elements include hydroxyl groups, iodine atoms, alkyl groups, and alkoxy groups.

[0174] Furthermore, the polymer may also contain structural units (III) represented by the following formulas (1f) to (2f) (hereinafter also referred to as "structural unit (III-2)").

[0175]

[0176] In the above equations (1f) to (2f), R αｆ Each of these is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. βｆ Each of these is independently a hydrogen atom or a chain alkyl group having 1 to 5 carbon atoms. １ is an integer between 1 and 4.

[0177] The above R βｆ Preferably, it is a hydrogen atom, a methyl group, or an ethyl group. １ 1 or 2 is preferred.

[0178] While there are no particular limitations on specific examples of structural unit (III) (including structural unit (III-1) and structural unit (III-2)), one example is a structure represented by the following formula.

[0179]

[0180]

[0181]

[0182]

[0183] In the formula, R １７ This is equivalent to the above equation (iii).

[0184] The base polymer (A-1) may contain one or more structural units (III) in combination.

[0185] The lower limit of the content of structural unit (III) (total content if multiple types are included) is preferably 1 mol%, more preferably 5 mol%, and even more preferably 8 mol%, relative to the total structural units constituting the base polymer (A-1). The upper limit of the above content is preferably 70 mol%, more preferably 65 mol%, and even more preferably 60 mol%. By setting the content of structural unit (III) within the above range, the pattern-forming properties of the radiation-sensitive composition can be further improved. If the acid-dissociable group has an iodine group, the sensitivity can be further improved.

[0186] [Structural Unit (IV)] Polymer (A-1) may contain structural unit (IV) which includes at least one selected from the group consisting of lactone structure, cyclic carbonate structure, sultone structure, and cyclic sulfone structure. The presence of structural unit (IV) in the base polymer (A-1) allows for adjustment of its solubility in the developer, and as a result, the radiation-sensitive composition can improve lithography performance such as resolution. Furthermore, it can improve the adhesion between the resist pattern formed from the base polymer (A-1) and the substrate.

[0187] Examples of structural units (IV) include those represented by the following formulas (T-1) to (T-11).

[0188]

[0189] In the above formula, R Ｌ１ R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Ｌ２ ~R Ｌ５ These are, independently, a hydrogen atom, a C1-C4 alkyl group, a cyano group, a trifluoromethyl group, a methoxy group, a methoxycarbonyl group, a hydroxyl group, a hydroxymethyl group, a dimethylamino group, and -COOR. Ｌ６ That is. R Ｌ６ R is a monovalent hydrocarbon group having 1 to 20 carbon atoms. Ｌ４ and R Ｌ５ These may be divalent alicyclic hydrocarbon groups having 3 to 8 carbon atoms, which can be combined with each other and bonded together with the carbon atoms. ２is a single bond or a divalent linking group. X is an oxygen atom or a methylene group. k is an integer from 0 to 3. m is an integer from 1 to 3.

[0190] The above R Ｌ４ and R Ｌ５ When these are combined with each other, the divalent alicyclic hydrocarbon group having 3 to 8 carbon atoms, formed together with the carbon atoms to which they are bonded, is R in formula (1) above. １１ , R １２ , R １３ Among the monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, groups obtained by removing one hydrogen atom from the corresponding carbon number group can be suitably adopted. One or more hydrogen atoms on this alicyclic hydrocarbon group may be substituted with hydroxyl groups.

[0191] The above R Ｌ６ As a monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the above formula (1), R １１ , R １２ , R １３ Monovalent hydrocarbon groups having 1 to 20 carbon atoms can be suitably used in this material.

[0192] The above L ２ Examples of divalent linking groups represented by include divalent linear or branched hydrocarbon groups having 1 to 10 carbon atoms, divalent alicyclic hydrocarbon groups having 4 to 12 carbon atoms, or groups composed of one or more of these hydrocarbon groups and at least one of the groups -CO-, -O-, -NH-, and -S-.

[0193] The above L ２ In this, the divalent linear or branched hydrocarbon group having 1 to 10 carbon atoms is R in formula (1) above. １１ , R １２ , R １３ In this material, monovalent chain hydrocarbon groups having 1 to 20 carbon atoms can be suitably adopted, specifically those obtained by removing one hydrogen atom from the group corresponding to the number of carbon atoms.

[0194] The above L ２ In this, the divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms is R in formula (1). １１ , R １２ , R １３ , R １４Among the monovalent alicyclic hydrocarbon groups having 1 to 20 carbon atoms, a group obtained by removing one hydrogen atom from the corresponding group having the same number of carbon atoms can be preferably employed.

[0195] As the structural unit (IV), among these, a structural unit containing a lactone structure is preferable.

[0196] The base polymer (A-1) may contain one or a combination of two or more of the structural units (IV).

[0197] When the base polymer (A-1) contains the structural unit (IV), the lower limit of the content ratio of the structural unit (IV) (when a plurality of types are included, the total content ratio) is preferably 1 mol%, more preferably 3 mol%, and even more preferably 5 mol% with respect to all the structural units constituting the base polymer (A-1). The upper limit of the content ratio is preferably 50 mol%, more preferably 40 mol%, and even more preferably 30 mol%. By setting the content ratio of the structural unit (IV) within the above range, the lithography performance such as resolution of the radiation-sensitive composition and the adhesion of the formed resist pattern to the substrate can be further improved.

[0198] [Structural unit (V)] The base polymer (A-1) can contain a structural unit (V) containing a polar group (however, excluding those corresponding to the structural units (I) to (IV)). By further having the structural unit (V), the base polymer (A-1) can adjust the solubility in the developer, and as a result, the lithography performance such as the resolution of the radiation-sensitive composition can be improved. Examples of the polar group include a hydroxy group, a carboxy group, a cyano group, a nitro group, a sulfonamide group, etc. Among these, a hydroxy group and a carboxy group are preferable, and a hydroxy group is more preferable.

[0199] Examples of the structural unit (V) include structural units represented by the following formulae.

[0200]

[0201]

[0202] In the above formula, R ＫThis is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0203] The base polymer (A-1) may contain one or more structural units (V).

[0204] When the base polymer (A-1) contains the structural unit (V), the lower limit of the content of the structural unit (V) (or the total content if multiple types are included) is preferably 0.5 mol%, more preferably 1 mol%, and even more preferably 3 mol%, relative to the total structural units constituting the base polymer (A-1). The upper limit of the content is preferably 50 mol%, more preferably 40 mol%, and even more preferably 30 mol%. By setting the content of the structural unit (V) within the above range, the lithographic performance, such as resolution, of the radiation-sensitive composition can be further improved.

[0205] (Structural Unit (VI)) Polymer (A-1) may contain structural unit (VI) which includes an amide bond.

[0206] The above structural unit (VI) is preferably a structural unit derived from a compound represented by the following formula (8). (In formula (8), R １００ L is a hydrogen atom, a fluorine atom, or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. １０１ R is a single bond or a divalent linking group. １０１ and R １０２ These are, independently, monovalent organic groups having 1 to 20 carbon atoms.

[0207] R １００ The substituent or unsubstituted C1-C6 alkyl group represented by the above formula (iii) is R １７ A substituent represented by or an unsubstituted alkyl group having 1 to 6 carbon atoms can be preferably used.

[0208] L １０１The divalent linking group represented by is preferably a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, or a divalent chain hydrocarbon group having 1 to 10 carbon atoms, with benzenediyl groups, ethanediyl groups, propanediyl groups, etc., being more preferred. Some or all of the hydrogen atoms of these groups may be substituted with the monovalent heteroatom-containing group described above.

[0209] R １０１ and R １０２ As a monovalent organic group having 1 to 20 carbon atoms, R in formula (1) above is an example. １１ , R １２ , R １３ A monovalent organic group having 1 to 20 carbon atoms, represented by , can be suitably used. Among these, R １０１ and R １０２ A C1-C5 alkyl group is preferred.

[0210] The base polymer (A-1) may contain one or more structural units (VI) in combination.

[0211] When the base polymer (A-1) contains the structural unit (VI), the lower limit of the content of the structural unit (VI) (or the total content if multiple types are included) is preferably 1 mol%, more preferably 5 mol%, and even more preferably 8 mol%, relative to the total structural units constituting the base polymer (A-1). The upper limit of the content is preferably 50 mol%, more preferably 40 mol%, and even more preferably 30 mol%.

[0212] [Structural Unit (VII)] In addition to the structural units listed above, the base polymer (A-1) may include structural units having an aliphatic hydrocarbon group represented by the following formula (9) (hereinafter also referred to as "structural unit (VII)"). (In the above formula (9), R １α R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. ２α (This refers to a monovalent hydrocarbon group having 1 to 40 carbon atoms.)

[0213] In the above formula (9), R ２α As a monovalent hydrocarbon group having 1 to 40 carbon atoms represented by the above formula (1), R １１ , R １２ , R１３ In this material, monovalent hydrocarbon groups with 1 to 20 carbon atoms can be expanded to groups with 1 to 40 carbon atoms, which can be suitably adopted.

[0214] The base polymer (A-1) may contain one or more structural units (VII) in combination.

[0215] When the base polymer (A-1) contains the above structural unit (VII), the lower limit of the content of the above structural unit (VII) (total content if multiple types are included) is preferably 1 mol%, more preferably 3 mol%, and even more preferably 5 mol%, relative to the total structural units constituting the base polymer (A-1). The upper limit of the above content is preferably 50 mol%, more preferably 40 mol%, and even more preferably 30 mol%.

[0216] (Method for synthesizing base polymer (A-1)) Base polymer (A-1) can be synthesized, for example, by polymerizing monomers that give each structural unit in a suitable solvent using a radical polymerization initiator or the like.

[0217] Examples of the radical polymerization initiators mentioned above include azo-based radical initiators such as azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and dimethyl 2,2'-azobisisobutyrate; and peroxide-based radical initiators such as benzoyl peroxide, t-butyl hydroperoxide, and cumene hydroperoxide. Among these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferred, and AIBN is more preferred. These radical initiators can be used individually or in combination of two or more.

[0218] Examples of solvents used in the above polymerization include: alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane; cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, and norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, and cumene; halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, and chlorobenzene; saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate, and methyl propionate; lactones such as γ-butyrolactone and δ-valerolactone; ketones such as acetone, 2-butanone, 4-methyl-2-pentanone, 2-heptanone, and cyclohexanone; and ethers such as tetrahydrofuran, dimethoxyethanes, and diethoxyethanes. Examples include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-methoxy-2-propanol, and 4-methyl-2-pentanol. The solvent used in these polymerizations may be used alone or in combination of two or more.

[0219] The reaction temperature in the polymerization described above is usually 40°C to 150°C, with 50°C to 120°C being preferred. The reaction time is usually 1 hour to 48 hours, with 1 hour to 24 hours being preferred.

[0220] The molecular weight of the base polymer (A-1) is not particularly limited, but the lower limit of the polystyrene-equivalent weight-average molecular weight (Mw) determined by gel permeation chromatography (GPC) is preferably 2,000, more preferably 2,500, and even more preferably 3,000. The upper limit of Mw is preferably 30,000, and more preferably 20,000. By setting the Mw of the base polymer (A-1) within the above range, good developability can be imparted to the resulting resist film.

[0221] The ratio of Mw to the polystyrene-equivalent number-average molecular weight (Mn) (Mw / Mn) of the base polymer (A-1) determined by GPC is usually 1 or more and 5 or less, preferably 1 or more and 3 or less, and more preferably 1 or more and 2 or less.

[0222] In this specification, the Mw and Mn values ​​of polymers are measured using gel permeation chromatography (GPC) under the following conditions.

[0223] GPC columns: 2 x G2000HXL, 1 x G3000HXL, 1 x G4000HXL (all manufactured by Tosoh Corporation) Column temperature: 40°C Elution solvent: Tetrahydrofuran Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0224] The content of the base polymer (A-1) is preferably 60% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 70% by mass or more, based on the total solid content of the radiation-sensitive composition.

[0225] (Polymer (A-2)) Polymer (A-2) contains structural unit (I-2) having a phenolic hydroxyl group. The base polymer (A-2) may also contain other structural units in addition to structural unit (I-2). Each structural unit is described below.

[0226] The structural unit (I-2) is preferably represented by the following formula (10).

[0227] (In formula (10), R ２０１ R is a monovalent organic group having 1 to 20 carbon atoms. ２０１ If multiple R ２０１ (These two values ​​are either identical or different. a is an integer between 0 and 3.)

[0228] R ２０１ As a monovalent organic group having 1 to 20 carbon atoms represented by the above formula (1), R １１ , R １２ , R １３ A monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably used.

[0229] Polymer (A-2) is a novolac polymer obtained by condensing a phenol compound and an aldehyde in the presence of a catalyst.

[0230] Examples of the phenol compounds mentioned above include phenol; o-, m- or p-cresol; 2,3-, 2,5-, 3,4- or 3,5-xylenol; 2,3,4- or 2,3,5-trimethylphenol; 2-,3- or 4-tert-butylphenol; 2-tert-butyl-4- or 5-methylphenol; 2-,4- or 5-methylresorcinol; 2-,3- or 4-methoxyphenol; 2,3-, 2,5- or 3,5-dimethoxyphenol; 2-methoxyresorcinol; 4-tert-butylcatechol; 2-,3- or 4-ethylphenol; 2,5- or 3,5-diethylphenol; 2,3,5-triethylphenol; 2-naphthol; 1,3-, 1,5- or 1,7-dihydroxynaphthalene; and polyhydroxytriphenylmethane compounds obtained by the condensation of xylenol with hydroxybenzaldehyde. These phenol compounds can be used individually or in combination of two or more. Among these, o-, m-, or p-cresol; 2,3-, 2,5-, 3,4-, or 3,5-xylenol; and 2,3,4-, or 2,3,5-trimethylphenol are preferred as phenol compounds.

[0231] Examples of aldehydes include aliphatic aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, acrolein, or crotonaldehyde; alicyclic aldehydes such as cyclohexanealdehyde, cyclopentanaldehyde, or furylacrolein; aromatic aldehydes such as furfural, benzaldehyde, o-, m-, or p-methylbenzaldehyde, p-ethylbenzaldehyde, 2,4-, 2,5-, 3,4-, or 3,5-dimethylbenzaldehyde, or o-, m-, or p-hydroxybenzaldehyde; and aromatic aliphatic aldehydes such as phenylacetaldehyde or cinnamaldehyde. These aldehydes can be used individually or in combination of two or more. Among these, formaldehyde is preferred because it is readily available industrially.

[0232] The condensation reaction between the above phenol compound and aldehyde can be carried out according to conventional methods.

[0233] The polymer (A-2) mentioned above includes polymers containing structural units represented by the following formulas (10-1) to (10-6). In the following formulas, the arrangement of each structural unit may be block-like or random.

[0234] The lower limit of the content of the above structural unit (I-2) (total if there are multiple types of structural unit (I-2)) is preferably 20 mol%, more preferably 30 mol%, and even more preferably 40 mol%, relative to the total structural units constituting the polymer (A-2). The upper limit of the above content is preferably 100 mol%. By setting the content of structural unit (I-1) within the above range, the radiation-sensitive composition can be made even more sensitive.

[0235] The weight-average molecular weight (Mw) and Mw / Mn of polymer (A-2) can be given within the same range as those for polymer (A-1) above.

[0236] <Solvent (E)> The first radiation-sensitive composition according to this embodiment contains a solvent (E). The solvent (E) is not particularly limited as long as it is a solvent capable of dissolving or dispersing at least the polymer (A), the first radiation-sensitive acid generator (B), the second radiation-sensitive acid generator (C), and optionally the crosslinking agent (Q), acid diffusion control agent (D), etc., described below.

[0237] Examples of solvents include alcohol-based solvents, ether-based solvents, ketone-based solvents, amide-based solvents, ester-based solvents, and hydrocarbon-based solvents.

[0238] Examples of alcohol-based solvents include monoalcohol solvents having 1 to 18 carbon atoms, such as iso-propanol, 4-methyl-2-pentanol, 3-methoxybutanol, n-hexanol, 2-ethylhexanol, furfuryl alcohol, cyclohexanol, 3,3,5-trimethylcyclohexanol, and diacetone alcohol; polyhydric alcohol solvents having 2 to 18 carbon atoms, such as ethylene glycol, 1,2-propylene glycol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, and tripropylene glycol; and polyhydric alcohol partial ether solvents in which some of the hydroxyl groups of the above-mentioned polyhydric alcohol solvents have been etherified.

[0239] In this embodiment, alcohol acid ester solvents such as methyl lactate, ethyl lactate, propyl lactate, butyl lactate, methyl 2-hydroxyisobutyrate, i-propyl 2-hydroxyisobutyrate, i-butyl 2-hydroxyisobutyrate, and n-butyl 2-hydroxyisobutyrate are also included in the alcohol-based solvents.

[0240] Examples of ether-based solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether; cyclic ether solvents such as tetrahydrofuran and tetrahydropyran; aromatic ring-containing ether solvents such as diphenyl ether and anisole (methylphenyl ether); and polyhydric alcohol ether solvents obtained by etherifying the hydroxyl groups of the above-mentioned polyhydric alcohol solvents.

[0241] Examples of ketone solvents include: linear ketone solvents such as acetone, butanone, methyl isobutyl ketone, and 2-heptanone; cyclic ketone solvents such as cyclopentanone, cyclohexanone, and methylcyclohexanone; and 2,4-pentanedione, acetonylacetone, and acetophenone.

[0242] Examples of amide solvents include cyclic amide solvents such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone; and chain-like amide solvents such as N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, and N-methylpropionamide.

[0243] Examples of ester solvents include monocarboxylic acid ester solvents such as n-butyl acetate and methyl 3-methoxypropionate; polyhydric alcohol partial ether acetate solvents such as diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, and dipropylene glycol monomethyl ether acetate; lactone solvents such as γ-butyrolactone and valerolactone; carbonate solvents such as diethyl carbonate, ethylene carbonate, and propylene carbonate; and polyhydric carboxylic acid diester solvents such as propylene glycol diacetate, methoxytriglycol acetate, diethyl oxalate, ethyl acetoethyl acetate, and diethyl phthalate.

[0244] Examples of hydrocarbon solvents include aliphatic hydrocarbon solvents such as n-hexane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, di-isopropylbenzene, and n-amyl alcohol naphthalene.

[0245] Among these, ester solvents, ether solvents, and ketone solvents are preferred, polyvalent partial ether acetate solvents, lactone solvents, monocarboxylic acid ester solvents, and linear ketone solvents are more preferred, and 2-heptanone, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, γ-butyrolactone, ethyl lactate, cyclohexanone, cyclopentanone, propylene glycol monomethyl ether, and methyl 3-methoxypropionate are even more preferred. The radiation-sensitive composition may contain one or more solvents.

[0246] <Crosslinking agent (Q)> If the above radiation-sensitive composition is a negative-type radiation-sensitive composition, it may contain a crosslinking agent (Q). The type of crosslinking agent (Q) is not particularly limited, and examples include crosslinking agents having two or more crosslinking groups in one molecule. The number of crosslinking groups is two or more in one molecule, preferably 2 to 10, and more preferably 2 to 6.

[0247] The above crosslinkable group is not particularly limited, but it is preferable to have at least one selected from the group consisting of a methylol group, an alkoxymethyl group, a glycidyl group, a (meth)acryloyl group, and a vinyl group, more preferably a methylol group or an alkoxymethyl group, and even more preferably an alkoxymethyl group.

[0248] The above-mentioned radiation-sensitive composition can be made into a negative-type pattern-forming composition by containing a crosslinking agent (Q). Specifically, in the exposed area, the acids generated from the first radiation-sensitive acid generator (B) and the second radiation-sensitive acid generator (C) promote the crosslinking reaction of the polymer (A) by the crosslinking agent (Q), causing it to harden and become substantially insoluble in alkaline developer. On the other hand, by removing the unexposed area with alkaline developer, a negative-type pattern can be formed.

[0249] The crosslinking agent (Q) is not particularly limited, but examples include amino-based crosslinking agents having one or more nitrogen atoms, and phenolic hydroxyl group-containing crosslinking agents.

[0250] The above-mentioned amino-based crosslinking agents are not particularly limited, as long as they have one or more nitrogen atoms, but examples include glycoluryl-type crosslinking agents having a glycoluryl skeleton, melamine-type crosslinking agents having a melamine skeleton, and urea-type crosslinking agents having a cyclic alkylene urea skeleton.

[0251] Among these, amino-based crosslinking agents are preferred as the crosslinking agent (Q), and glycoluryl-type crosslinking agents and melamine-type crosslinking agents are more preferred.

[0252] Examples of the glycoluryl-type crosslinking agent mentioned above include the compound (Q1) represented by the following formula (Q1). (In formula (Q1), R３１ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. However, at least two R ３１ is *-R ３３ -OR ３４ (R ３３ R is a divalent hydrocarbon group having 1 to 10 carbon atoms. ３４ R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. * indicates a bond with a nitrogen atom. ３２ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms.

[0253] The above R ３１ In this, the monovalent organic group having 1 to 20 carbon atoms is R in formula (1) above. １１ , R １２ , R １３ A monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably used.

[0254] The above R ３３ In this, the divalent hydrocarbon group having 1 to 10 carbon atoms is R in formula (1) above. １１ , R １２ , R １３ In this context, a monovalent hydrocarbon group having 1 to 20 carbon atoms can be suitably selected, specifically one group with one hydrogen atom removed from the corresponding carbon number group.

[0255] The above R ３４ In this, the monovalent hydrocarbon group having 1 to 10 carbon atoms is R in formula (1) above. １１ , R １２ , R １３ Among the monovalent hydrocarbon groups having 1 to 20 carbon atoms, those with the corresponding number of carbon atoms can be suitably adopted.

[0256] The above R ３２ In this, the monovalent organic group having 1 to 10 carbon atoms is R in formula (1) above. １１ , R １２ , R １３ Among the monovalent organic groups having 1 to 20 carbon atoms represented by [formula], those with the corresponding number of carbon atoms can be suitably adopted.

[0257] As the glycoluryl type crosslinking agent, the compound represented by the following formula (Q1-1) (Q1-1) is preferred. (In formula (Q1-1), R ３２ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms. ３３ Each of these is independently a divalent hydrocarbon group having 1 to 10 carbon atoms. ３４ These are, independently, monovalent hydrocarbon groups having 1 to 10 carbon atoms.

[0258] R ３２ A monovalent organic group having 1 to 10 carbon atoms, R ３３ A divalent hydrocarbon group having 1 to 10 carbon atoms, R ３４ As the monovalent hydrocarbon group having 1 to 10 carbon atoms in the above formula (Q1), the monovalent organic group having 1 to 10 carbon atoms, the divalent hydrocarbon group having 1 to 10 carbon atoms, and the monovalent hydrocarbon group having 1 to 10 carbon atoms can be suitably adopted.

[0259] Among these, the above R ３２ As such, a hydrogen atom or an alkyl group having 1 to 3 carbon atoms is preferred. ３３ As for the group, an alkylene group having 1 to 5 carbon atoms is preferred, and a methylene group or an ethylene group is more preferred. ３４ A C1-C5 alkyl group is preferred, and a methyl group or a butyl group is more preferred.

[0260] Examples of glycoluryl-type crosslinking agents include those with the following formulas.

[0261] (In the formula, Et is an ethyl group, ｎ Bu is an n-butyl group, ｉ Pr represents an isopropyl group.

[0262] Examples of the melamine-type crosslinking agent mentioned above include the compound (Q2) represented by the following formula (Q2). (In formula (Q2), R ４ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. However, at least two R ４ is *-R ４１ -OR ４２ (R４１ R is a divalent hydrocarbon group having 1 to 10 carbon atoms. ４２ This represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. * indicates a bond with a nitrogen atom.

[0263] The above R ４ In this, the monovalent organic group having 1 to 20 carbon atoms is R in formula (1) above. １１ , R １２ , R １３ A monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably used.

[0264] The above R ４１ In this, the divalent hydrocarbon group having 1 to 10 carbon atoms is R in formula (1) above. １１ , R １２ , R １３ Among the monovalent hydrocarbon groups having 1 to 20 carbon atoms, groups with one hydrogen atom removed from those with the corresponding number of carbon atoms can be suitably adopted.

[0265] The above R ４２ In this, the monovalent hydrocarbon group having 1 to 10 carbon atoms is R in formula (1) above. １１ , R １２ , R １３ Among the monovalent hydrocarbon groups having 1 to 20 carbon atoms, those with the corresponding number of carbon atoms can be suitably adopted.

[0266] As the melamine-type crosslinking agent, a compound represented by the following formula (Q2-1) (Q2-1) is preferred. (In formula (Q2-1), R ４１ Each of these is independently a divalent hydrocarbon group having 1 to 10 carbon atoms. ４２ These are, independently, monovalent hydrocarbon groups having 1 to 10 carbon atoms.

[0267] R ４１ A divalent hydrocarbon group having 1 to 10 carbon atoms, R ４２ As the monovalent hydrocarbon group having 1 to 10 carbon atoms in the above formula (Q2), the divalent hydrocarbon group having 1 to 10 carbon atoms and the monovalent hydrocarbon group having 1 to 10 carbon atoms listed above can be suitably adopted.

[0268] Among these, the above R４１ As for the group, an alkylene group having 1 to 5 carbon atoms is preferred, and a methylene group or an ethylene group is more preferred. ４２ Preferably, the alkyl group has 1 to 5 carbon atoms, and more preferably, a methyl group.

[0269] Examples of melamine-type crosslinking agents include those with the following formulas.

[0270] (In the formula, Me is a methyl group, Et is an ethyl group, ｎ Bu is an n-butyl group, ｉ Pr represents an isopropyl group.

[0271] Furthermore, the following crosslinking agents can be cited as urea-type crosslinking agents having the above-mentioned cyclic alkylene urea skeleton.

[0272]

[0273] Furthermore, the following crosslinking agents can be listed as phenolic hydroxyl group-containing crosslinking agents.

[0274]

[0275] In the present invention, the above-mentioned crosslinking agent (Q) can be used alone or in combination of two or more types.

[0276] The lower limit of the content of the above-mentioned crosslinking agent (Q) (total if multiple types of crosslinking agents (Q) are included) is preferably 0.5 parts by mass, more preferably 1 part by mass, and even more preferably 3 parts by mass per 100 parts by mass of polymer (A). The upper limit of the above-mentioned content is preferably 30 parts by mass, and more preferably 20 parts by mass. The content of the above-mentioned crosslinking agent (Q) is appropriately selected depending on the type of polymer used, exposure conditions, and the required sensitivity. This makes it possible to exhibit excellent CDU, pattern circularity, and pattern rectangularity when forming a resist pattern.

[0277] <Acid Diffusion Control Agent (D)> The above radiation-sensitive composition may optionally contain an acid diffusion control agent (D). The acid diffusion control agent (D) controls the diffusion phenomenon of acids generated from the first radiation-sensitive acid generator (B) and the second radiation-sensitive acid generator (C) in the resist film upon exposure, and has the effect of suppressing undesirable chemical reactions in the non-exposed areas. Furthermore, the storage stability of the resulting radiation-sensitive composition is improved. In addition, the resolution of the resist pattern is further improved, and changes in the line width of the resist pattern due to variations in the holding time from exposure to development can be suppressed, resulting in a radiation-sensitive composition with excellent process stability.

[0278] Examples of acid diffusion control agents (D) include compounds represented by the following formula (7) (hereinafter also referred to as "nitrogen-containing compounds (I)"), compounds having two nitrogen atoms in the same molecule (hereinafter also referred to as "nitrogen-containing compounds (II)"), compounds having three nitrogen atoms (hereinafter also referred to as "nitrogen-containing compounds (III)"), amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like.

[0279]

[0280] In the above formula (7), R ２２ , R ２３ and R ２４ Each of these is independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group.

[0281] Examples of nitrogen-containing compounds (I) include monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; trialkylamines such as triethylamine and triamylamine; and aromatic amines such as aniline and 2,6-di-i-propylaniline.

[0282] Examples of nitrogen-containing compounds (II) include ethylenediamine, N,N,N',N'-tetramethylethylenediamine, and 1,1',1'',1''''-(ethylenedinitrilo)tetrakis(2-propanol).

[0283] Examples of nitrogen-containing compounds (III) include polyamine compounds such as polyethyleneimine and polyallylamine; and polymers such as dimethylaminoethylacrylamide.

[0284] Examples of amide group-containing compounds include formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, benzamide, pyrrolidone, and N-methylpyrrolidone.

[0285] Examples of urea compounds include urea, methyl urea, 1,1-dimethyl urea, 1,3-dimethyl urea, 1,1,3,3-tetramethyl urea, 1,3-diphenyl urea, and tributylthiourea.

[0286] Examples of nitrogen-containing heterocyclic compounds include pyridines such as pyridine, 2-methylpyridine, 2,6-di-t-butylpyridine, and 2,6-diisopropylpyridine; morpholines such as N-propylmorpholine and N-(undecylcarbonyloxyethyl)morpholine; and pyrazines, pyrazoles, terpyridines, and 2-phenylbenzimidazole.

[0287] Furthermore, compounds having acid-dissociable groups can also be used as the nitrogen-containing organic compounds mentioned above. Examples of nitrogen-containing organic compounds having such acid-dissociable groups include N-t-butoxycarbonylpiperidine, 1-(tert-butoxycarbonyl)-4-hydroxypiperidine, N-t-butoxycarbonylimidazole, N-t-butoxycarbonylbenzimidazole, N-t-butoxycarbonyl-2-phenylbenzimidazole, N-(t-butoxycarbonyl)di-n-octylamine, N-(t-butoxycarbonyl)diethanolamine, N-(t-butoxycarbonyl)dicyclohexylamine, N-(t-butoxycarbonyl)diphenylamine, N-t-butoxycarbonyl-4-hydroxypiperidine, N-t-butoxycarbonyl-4-acetoxypiperidine, and N-t-amyloxycarbonyl-4-hydroxypiperidine.

[0288] Furthermore, as the acid diffusion control agent (D), an onium salt compound (d) that generates an acid with a higher pKa than the acid generated by the first radiation-sensitive acid generator (B) and the second radiation-sensitive acid generator (C) upon irradiation with radiation can also be suitably used.

[0289] The onium salt compound (d) is preferably represented by the following formulas (8-1) to (8-4).

[0290] In the above formulas (8-1) to (8-4), J ＋ It is a sulfonium cation, U ＋ This is an iodonium cation. - and Q - Each of them is independent of OH - , R α -COO - , R α -SO ３ - It is an organic acid anion represented by the above formulas (8-1) to (8-2). α R is a monovalent organic group having 1 to 30 carbon atoms. In the above formulas (8-3) to (8-4), α R is a single bond or a divalent organic group having 1 to 30 carbon atoms. As an example of the monovalent organic group having 1 to 30 carbon atoms, R in formula (1) above is... １１ , R １２ , R １３ A monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably adopted as a group with 1 to 30 carbon atoms. As the above-mentioned divalent organic group having 1 to 30 carbon atoms, a group obtained by removing one hydrogen atom from the above-mentioned monovalent organic group having 1 to 30 carbon atoms can be suitably adopted.

[0291] Examples of organic acid anions for the above-mentioned acid diffusion control agent include, but are not limited to, those listed below.

[0292]

[0293]

[0294] The onium cation in the above acid diffusion control agent is the Z of the above second radiation-sensitive acid generator (C2). ２ ＋An onium cation represented by can be suitably used.

[0295] When the above radiation-sensitive composition contains an acid diffusion control agent (D), the lower limit of the content of the acid diffusion control agent (D) (total in the case of multiple types) is preferably 0.1 parts by mass, more preferably 0.5 parts by mass, and still more preferably 1 part by mass, per 100 parts by mass of polymer (A). The upper limit of the above content is preferably 60 parts by mass, more preferably 50 parts by mass, and still more preferably 40 parts by mass. This allows for excellent sensitivity and pattern-forming properties during resist pattern formation.

[0296] (Other optional components) The above-mentioned radiation-sensitive composition may contain other optional components in addition to the components listed above. Examples of these other optional components include segregation accelerators, dissolution accelerators, surfactants, alicyclic skeleton-containing compounds, sensitizers, etc. These other optional components may be used individually or in combination of two or more types.

[0297] The surfactants mentioned above are not particularly limited, but non-fluorinated surfactants or non-silicone surfactants can be suitably used.

[0298] If the above radiation-sensitive composition contains the above optional component, the content of the above optional component is preferably 0.01 parts by mass or more, more preferably 0.03 parts by mass or more, per 100 parts by mass of the above polymer (A). Furthermore, it is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less.

[0299] <Method for preparing a radiation-sensitive composition> The above radiation-sensitive composition can be prepared by mixing a polymer (A), a first radiation-sensitive acid generator (B), a second radiation-sensitive acid generator (C), a solvent (E), and, if necessary, a crosslinking agent (Q), an acid diffusion control agent (D), etc., in predetermined proportions. After mixing, the above radiation-sensitive composition is preferably filtered using, for example, a filter with a pore size of about 0.05 μm to 0.40 μm. The solid content concentration of the above radiation-sensitive composition is usually 0.1% to 50% by mass, preferably 0.5% to 30% by mass, and more preferably 1% to 20% by mass.

[0300] ≪Pattern Forming Method≫ A pattern forming method according to one embodiment of the present invention includes a step (1) of applying the above-mentioned radiation-sensitive composition directly or indirectly to a substrate to form a resist film (hereinafter also referred to as the "resist film forming step"), a step (2) of exposing the resist film (hereinafter also referred to as the "exposure step"), and a step (3) of developing the exposed resist film (hereinafter also referred to as the "development step").

[0301] According to the above resist pattern formation method, a high-quality resist pattern can be formed because it uses the above-mentioned radiation-sensitive composition that can form a resist film with excellent sensitivity in the exposure process, exposure margin, depth of field, pattern rectangularity, storage stability, development defect performance, CDU, and pattern circularity. Each step will be described below.

[0302] [Resist Film Formation Process] In this process (step (1) above), a resist film is formed using the radiation-sensitive composition. Examples of substrates for forming this resist film include conventionally known materials such as silicon wafers, silicon dioxide wafers, and aluminum-coated wafers. Alternatively, an organic or inorganic anti-reflective film, such as those disclosed in Japanese Patent Publication No. 6-12452 or Japanese Patent Publication No. 59-93448, may be formed on the substrate. Examples of coating methods include spin coating, casting, and roll coating. After coating, pre-baking (PB) may be performed as needed to volatilize the solvent in the coating film. The PB temperature is usually 60°C to 150°C, with 80°C to 140°C being preferred. The PB time is usually 5 seconds to 600 seconds, with 10 seconds to 300 seconds being preferred.

[0303] The lower limit of the thickness of the formed resist film is preferably 10 nm, more preferably 15 nm, and even more preferably 20 nm. The upper limit of the thickness is preferably 9000 nm, and more preferably 4000 nm. In particular, when a thick resist film is exposed to KrF excimer laser light in the exposure process described later, the lower limit of the thickness may be 100 nm, 150 nm, or 200 nm.

[0304] [Exposure Process] In this process (process (2) above), the resist film formed in the resist film formation process, which is process (1) above, is exposed by irradiating it with radiation through a photomask (and, in some cases, through an immersion liquid such as water). The radiation used for exposure can be electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, KrF, EUV (extreme ultraviolet), X-rays, and gamma rays, depending on the line width of the desired pattern; electron beams, alpha rays, and other charged particle beams. Among these, the compositions of the present invention are particularly suitable for use with a KrF excimer laser, EUV, and ultraviolet light.

[0305] It is preferable to perform post-exposure baking (PEB) after the above exposure. This PEB creates a difference in solubility in the developer between the exposed and unexposed areas. The PEB temperature is usually 50°C to 180°C, with 80°C to 150°C being preferred. The PEB time is usually 5 seconds to 600 seconds, with 10 seconds to 300 seconds being preferred.

[0306] [Development Process] In this process (step (3) above), the resist film exposed in the exposure process, which is step (2) above, is developed. This allows a predetermined resist pattern to be formed. After development, it is common to wash with a rinsing solution such as water or alcohol and then dry it.

[0307] Examples of developers used in the above development process include, in the case of alkaline development, an alkaline aqueous solution containing at least one alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, and 1,5-diazabicyclo-[4.3.0]-5-nonene. Among these, an aqueous TMAH solution is preferred, and a 2.38% by mass aqueous TMAH solution is more preferred.

[0308] Furthermore, in the case of organic solvent development, examples of organic solvents include hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, alcohol solvents, or solvents containing organic solvents. Examples of the above organic solvents include one or more of the solvents listed above as solvents for the radiation-sensitive composition. Among these, ether solvents, ester solvents, and ketone solvents are preferred. As for ether solvents, glycol ether solvents are preferred, and ethylene glycol monomethyl ether and propylene glycol monomethyl ether are more preferred. As for ester solvents, acetate ester solvents are preferred, and n-butyl acetate and amyl acetate are more preferred. As for ketone solvents, chain ketones are preferred, and 2-heptanone is more preferred. The content of organic solvents in the developer is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 99% by mass or more. Examples of components other than organic solvents in the developer include water and silicone oil.

[0309] As mentioned above, either an alkaline developer or an organic solvent developer may be used as the developing solution.

[0310] Examples of development methods include immersing the substrate in a tank filled with developer solution for a certain period of time (dip method), developing by puddling the developer solution onto the substrate surface using surface tension and letting it remain still for a certain period of time (paddle method), spraying the developer solution onto the substrate surface (spray method), and continuously dispensing the developer solution while scanning a developer solution dispensing nozzle at a constant speed onto a substrate rotating at a constant speed (dynamic dispensing method).

[0311] ≪Compound≫ A compound according to one embodiment of the present invention is represented by the following formula (1'). (In formula (1'), X １１ is -I or -CN. However, X １１ If is -CN and n1 is 1, then X １１ SO ３ - It is located in the meta or ortho position relative to the group. １１ If there are multiple X １１These are either identical or different. n1 is an integer between 1 and 5. １ is an alkyl group, -OCOR １１ ,-COOR １２ , or -SO ２ R １３ That is. R １１ , R １２ , R １３ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. １ If multiple R １ Each of them may be the same or different. n2 is an integer between 0 and 5, where n1 + n2 ≤ 5. ２ ＋ This is an iodonium cation.

[0312] n1, R １ n2 is equivalent to equation (1) above.

[0313] M ２ ＋ The iodonium cation represented by the above M １ ＋ An iodonium cation represented by can be suitably used.

[0314] Specific examples of anions of the compound represented by the above formula (1') include, but are not limited to, the structure shown in the following formula.

[0315]

[0316] As a specific example of the compound represented by formula (1') above, a structure can be adopted in which the above anion and iodonium cation are appropriately combined.

[0317] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. The methods for measuring various physical properties are shown below.

[0318] [Weight-average molecular weight (Mw) and number-average molecular weight (Mn)] The Mw and Mn of the polymer were measured under the conditions described above. The degree of dispersion (Mw / Mn) was calculated from the measured results of Mw and Mn.

[0319] [ １３[C-NMR analysis] Polymer １３ C-NMR analysis was performed using a nuclear magnetic resonance spectrometer (JEOL Ltd.'s "JNM-Delta400").

[0320] <Synthesis of Polymers> The monomers used in the synthesis of each polymer in each example and comparative example are shown below. In the following synthesis examples, unless otherwise specified, parts by mass refers to the value when the total mass of the monomers used is 100 parts by mass, and mol% refers to the value when the total number of moles of the monomers used is 100 mol%.

[0321]

[0322] [Synthesis Example 1] (Synthesis of Polymer (A-1)) Monomers (M-1), (M-5), (M-9), and (M-12) were dissolved in 1-methoxy-2-propanol (200 parts by mass) in a molar ratio of 60 / 15 / 20 / 5 (mol%), and AIBN (2 mol%) was added as an initiator to prepare a monomer solution. 100 parts by mass of 1-methoxy-2-propanol was placed in a reaction vessel, and after purging with nitrogen for 30 minutes, the temperature inside the reaction vessel was raised to 80°C, and the monomer solution was added dropwise over 3 hours while stirring. The start of the dropwise addition was defined as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours. After the polymerization reaction was completed, the polymerization solution was cooled to below 30°C by water cooling. The cooled polymerization solution was added to methanol (2,000 parts by mass), and the precipitated white powder was filtered off. The filtered white powder was washed twice with methanol, filtered again, and dissolved in 1-methoxy-2-propanol (300 parts by mass). Then, methanol (500 parts by mass), triethylamine (50 parts by mass), and ultrapure water (10 parts by mass) were added, and the hydrolysis reaction was carried out at 70°C for 6 hours with stirring. After the reaction was complete, the residual solvent was removed by distillation, and the resulting solid was dissolved in acetone (100 parts by mass) and added dropwise to hexane (500 parts by mass) to solidify the polymer. The resulting solid was filtered and dried at 50°C for 13 hours to obtain a white powdery polymer (A-1) (yield: 80%). The Mw of polymer (A-1) was 15,600, and the Mw / Mn ratio was 1.18. １３¹³C-NMR analysis revealed that the content percentages of structural units derived from (M-1), (M-5), (M-9), and (M-12) were 60.8 mol%, 15.2 mol%, 19.3 mol%, and 4.7 mol%, respectively. Furthermore, in the monomer that gives structural unit (I-1), in the polymer, １３ 13C-NMR analysis confirmed the disappearance of the carbonyl group peak of the acetyl group, indicating that virtually all alkali-dissociable groups had been hydrolyzed to form phenolic hydroxyl groups.

[0323] [Synthesis Examples 2-8] (Synthesis of Polymers (A-2) to (A-8)) Polymers (A-2) to (A-8) were synthesized in the same manner as in Synthesis Example 1, except that monomers of the types and proportions shown in Table 1 below were used. Note that in the monomers that give structural unit (I), in the polymer, １３ 13C-NMR analysis confirmed the disappearance of the carbonyl group peak of the acetyl group, indicating that virtually all alkali-dissociable groups had been hydrolyzed to phenolic hydroxyl groups. The content percentage (mol%) and physical properties (Mw and Mw / Mn) of each structural unit of the obtained polymer are shown in Table 1 below. In Table 1, "-" indicates that the corresponding component was not used (the same applies to subsequent tables).

[0324]

[0325] <Synthesis of the primary radiation-sensitive acid generator (B)> [Synthesis Example B1] (Synthesis of onium salt compound (B-1)) The onium salt compound (B-1) as the primary radiation-sensitive acid generator (B) was synthesized according to the following synthesis scheme.

[0326]

[0327] 20.0 mmol of sodium 2,3,4,5,6-pentafluorobenzenesulfonate, 20.0 mmol of bis(4-(tert-butyl)phenyl)iodonium chloride, 50 g of dichloromethane, and 50 g of water were added to a reaction vessel and stirred at room temperature for 4 hours. Dichloromethane was added to the reaction mixture and extracted, and the organic layer was separated. The obtained organic layer was washed with saturated aqueous sodium chloride solution and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the compound (B-1) represented by the above formula (B-1) was obtained in good yield by purification by column chromatography.

[0328] [Synthesis Examples B2 to B7] (Synthesis of Onium Salt Compounds (B-2) to (B-7)) Except for appropriately changing the raw materials and precursors, the onium salt compounds as primary radioactive acid generators (B) represented by the following formulas (B-2) to (B-7) were synthesized in the same manner as in Synthesis Example B1.

[0329]

[0330] [Example B8] (Synthesis of onium salt compound (B-8)) The onium salt compound (B-8) as the primary radioactive acid generator (B) was synthesized according to the following synthesis scheme.

[0331]

[0332] 20.0 mmol of sodium 2-cyanobenzenesulfonate, 20.0 mmol of bis(4-(tert-butyl)phenyl)iodonium chloride, 50 g of dichloromethane, and 50 g of water were added to a reaction vessel and stirred at room temperature for 4 hours. Dichloromethane was added to the reaction mixture and extracted, and the organic layer was separated. The obtained organic layer was washed with saturated sodium chloride aqueous solution, and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the compound (B-8) represented by the above formula (B-8) was obtained in good yield by purification by column chromatography.

[0333] [Examples B9 to B14] (Synthesis of onium salt compounds (B-9) to (B-14)) Onium salt compounds as primary radioactive acid generators (B) represented by the following formulas (B-9) to (B-14) were synthesized in the same manner as in Example B8, except that the raw materials and precursors were appropriately changed.

[0334]

[0335] In addition to the synthesized components mentioned above, the following compounds were used.

[0336] [Polymers other than polymers (A-1) to (A-8)] A-i-1 to A-i-2: Polymers represented by the following formulas (A-i-1) to (A-i-2) (Hereafter, polymers represented by formulas (A-i-1) to (A-i-2) may be referred to as "polymer (A-i-1)" to "polymer (A-i-2)," respectively.)

[0337]

[0338] [Secondary Radiation-Inducing Acid Generators (C-1) to (C-10)] C-1 to C-10: Compounds represented by the following formulas (C-1) to (C-10) (Hereafter, the compounds represented by formulas (C-1) to (C-10) may be referred to as "Compound (C-1)" to "Compound (C-10)," respectively.)

[0339]

[0340] [Radiation-sensitive acid generators other than the first and second radiation-sensitive acid generators mentioned above] b-1 to b-6: Compounds represented by the following formulas (b-1) to (b-6) (Hereafter, compounds represented by formulas (b-1) to (b-6) may be referred to as "compound (b-1)" to "compound (b-6)," respectively.)

[0341]

[0342] [Acid Diffusion Control Agent (D)] D-1 to D-5: Compounds represented by the following formulas (D-1) to (D-5) (Hereafter, the compounds represented by formulas (D-1) to (D-5) may be referred to as "Compound (D-1)" to "Compound (D-5)," respectively.)

[0343]

[0344] [Crosslinking agent (Q)] Q-1 to Q-3: Compounds represented by the following formulas (Q-1) to (Q-3) (Hereafter, compounds (Q-1) to (Q-3) may be referred to as "compound (Q-1)" to "compound (Q-3)," respectively.)

[0345]

[0346] [Other Additives (W)] W-1 to W-5: Compounds represented by the following formulas (W-1) to (W-3) and additive compounds (W-4) to (W-5) (Hereinafter, compounds (W-1) to (W-5) may be referred to as "compound (W-1)" to "compound (W-5)," respectively.)

[0347]

[0348] W-4: MEGAFACE EFS-321 (manufactured by DIC Corporation) (non-fluorine-based) W-5: BYK-399 (manufactured by Big Chemie Japan Co., Ltd.) (non-silicone-based)

[0349] [Solvent (E)] E-1: Propylene glycol monomethyl ether acetate E-2: Propylene glycol monomethyl ether E-3: Ethyl lactate E-4: 2-Heptanone

[0350] [Preparation of positive-type radiation-sensitive composition for KrF exposure] [Example 1] 100 parts by mass of (A-1) as polymer (A), 5.0 parts by mass of (B-1) as first-stage radiation-sensitive acid generator (B), 2.0 parts by mass of (C-1) as second-stage radiation-sensitive acid generator (C), 1.0 part by mass of (D-1) as acid diffusion control agent (D), 0.05 parts by mass of (W-1) as other additive (W), and 700 parts by mass of a mixed solvent of (E-1) / (E-3) as solvent (E) were mixed and filtered through a membrane filter with a pore size of 0.2 μm to prepare a radiation-sensitive composition (J-1).

[0351] [Examples 2-36, 101-103 and Comparative Examples 1-7] Radiation-sensitive compositions (J-2) to (J-36), (J-101) to (J-103), and (CJ-1) to (CJ-7) were prepared in the same manner as in Example 1, except that the components of the types and amounts shown in Table 2 below were used.

[0352]

[0353] <Formation of a resist pattern using a positive-type radiation-sensitive composition for KrF exposure> The prepared positive-type radiation-sensitive composition for KrF exposure was applied to a 12-inch silicon wafer treated with hexamethyldisilazane using a spin coater (CLEAN TRACK ACT8 from Tokyo Electron Limited), and pre-bake (PB) was performed at 130°C for 60 seconds. Subsequently, a resist film with an average thickness of 400 nm was formed by cooling at 23°C for 30 seconds. Next, this resist film was exposed using a KrF excimer laser scanner (PAS5500 / 850C wavelength 248 nm from ASML) under optical conditions of NA = 0.68 and σ = 0.60, through a 150 nm line-and-space mask pattern. After exposure, post-exposure bake (PEB) was performed at 130°C for 60 seconds. Subsequently, the resist film was alkaline-developed using a 2.38% by mass aqueous solution of TMAH as the alkaline developer. After development, it was washed with water and then dried to form a positive-type resist pattern (150 nm line, 300 nm pitch).

[0354] <Evaluation> The resist patterns formed using the above-mentioned positive-type radiation-sensitive composition for KrF exposure were evaluated for sensitivity, exposure margin, depth of field, pattern rectangularity, number of development defects, and storage stability according to the following method. A scanning electron microscope (Hitachi High-Technologies Corporation's "CG-5000") was used to measure the length of the resist patterns. The results are shown in Table 3 below.

[0355] [Sensitivity] In forming a resist pattern using the above-mentioned positive-type radiation-sensitive composition for KrF exposure, the exposure amount used to form the 150 nm line and 300 nm pitch is defined as the optimal exposure amount, and this optimal exposure amount is defined as the sensitivity (mJ / cm²). ２ The sensitivity was set to 40 mJ / cm². ２ In the following cases, it is considered "good" and 40 mJ / cm². ２ If it exceeded this value, it was rated as "poor."

[0356] [EL Performance (Exposure Margin)] Within the exposure range including the optimal exposure amount mentioned above, the exposure amount is 1 mJ / cm². ２Each resist pattern was formed by varying the exposure dose, and the hole width of each pattern was measured using the scanning electron microscope described above. From the relationship between the obtained line width and exposure dose, the exposure dose E(165) at which the line width was 165 nm and the exposure dose E(135) at which the line width was 135 nm were determined, and the exposure margin (EL) was calculated using the formula: Exposure margin (EL) = (E(135) - E(165)) × 100 / (Optimal exposure dose). The larger the exposure margin value, the smaller the variation in the dimensions of the pattern obtained when the exposure dose is varied, and the higher the yield during device fabrication. EL performance was evaluated as "good" if it was 20% or more, and as "poor" if it was below 20%.

[0357] [Depth of Focus] In the resist pattern resolved at the optimal exposure amount determined in the sensitivity evaluation above, the dimensions were observed when the focus was changed in the depth direction. The margin in the depth direction where the pattern dimensions fall within 90% to 110% of the standard without bridging or residue was measured, and this measured value was defined as the depth of focus (nm). A larger depth of focus indicates a better result. A depth of focus of 250 nm or more is evaluated as "good," and a depth of focus of less than 250 nm is evaluated as "poor."

[0358] [Pattern Rectangularity] Line and space patterns with 150 nm lines and a 300 nm pitch, formed by irradiating with the optimal exposure amount determined in the sensitivity evaluation above, were observed using the scanning electron microscope described above, and the cross-sectional shape of the line and space patterns was evaluated. The rectangularity of the resist pattern was evaluated as follows: if the ratio of the length of the lower side to the length of the upper side in the cross-sectional shape of the line portion was 1 or more and 1.05 or less, it was evaluated as "A" (very good); if it was greater than 1.05 and 1.10 or less, it was evaluated as "B" (good); and if it was greater than 1.10, it was evaluated as "C" (poor).

[0359] [Storage Stability] The above KrF exposure-positive radiation-sensitive composition was stored at 35°C for 30 days, and then the optimal exposure amount, i.e., sensitivity S30, for forming a line-and-space pattern with a 150 nm line and a 300 nm pitch was measured again. The ratio of the change in sensitivity after 30 days of storage was calculated based on the following formula, compared to the sensitivity S0 before storage. A change ratio of 0% or more and 1.0% or less was evaluated as "A" (good), a change ratio of more than 1.0% and 1.5% or less was evaluated as "B" (good), and a change ratio of more than 1.5% was evaluated as "B" (poor). Sensitivity change ratio (%) = {|S30-S0| / S0} × 100

[0360] [Development Defect Count] A resist film was exposed at the optimal exposure level to form a line-and-space pattern with 150 nm lines and a 300 nm pitch, and this was used as a wafer for defect inspection. The number of defects on this wafer was measured using a defect inspection device (KLA-Tencor's "KLA2810"). Defects with a diameter of 50 μm or less were judged to be originating from the resist film, and their number was calculated. After development, the number of defects judged to be originating from the resist film was evaluated as "good" if it was 100 or less, and as "poor" if it exceeded 100.

[0361]

[0362] As is clear from the results in Table 3, when the radiation-sensitive composition of the example was used in KrF positive exposure, it exhibited good sensitivity, exposure margin, depth of field, pattern rectangularity, storage stability, and development defect performance, whereas the comparative example did not satisfy any of these characteristics simultaneously. Therefore, when the radiation-sensitive composition of the example is used in KrF positive exposure, it is possible to form a resist pattern with optimal sensitivity, excellent roughness performance, pattern shape, and yield.

[0363] [Preparation of Negative-Type Radiation-Sensitive Composition for KrF Exposure] [Example 37] A radiation-sensitive composition (J-37) was prepared by mixing 100 parts by mass of (A-5) as a polymer (A), 3.0 parts by mass of (B-1) as a first radiation-sensitive acid generator (B), 1.5 parts by mass of (C-1) as a second radiation-sensitive acid generator (C), 1.0 part by mass of (D-1) as an acid diffusion control agent (D), 5.0 parts by mass of (Q-1) as a crosslinking agent (Q), 0.05 parts by mass of (W-1) as other additives (W), and 300 parts by mass of a mixed solvent of (E-1) / (E-4) as a solvent (E), and filtering the mixture through a membrane filter with a pore size of 0.2 μm.

[0364] [Examples 38-54 and Comparative Examples 8-13] Radiation-sensitive compositions (J-38) to (J-54) and (CJ-8) to (CJ-13) were prepared in the same manner as in Example 37, except that the components used were of the types and in the amounts shown in Table 4 below.

[0365]

[0366] <Formation of a resist pattern using a negative-type radiation-sensitive composition for KrF exposure> The prepared negative-type radiation-sensitive composition for KrF exposure was applied to a 12-inch silicon wafer treated with hexamethyldisilazane using a spin coater (CLEAN TRACK ACT8 from Tokyo Electron Limited), and pre-bake (PB) was performed at 130°C for 60 seconds. Subsequently, a resist film with an average thickness of 3.0 μm was formed by cooling at 23°C for 30 seconds. Next, this resist film was exposed using a KrF excimer laser scanner (PAS5500 / 850C wavelength 248 nm from ASML) under optical conditions of NA = 0.68 and σ = 0.60, via a mask pattern with 500 nm holes and a 1000 nm pitch. After exposure, post-exposure bake (PEB) was performed at 130°C for 60 seconds. Subsequently, the resist film was alkaline-developed using a 2.38% by mass aqueous solution of TMAH as the alkaline developer. After development, it was washed with water and then dried to form a positive-type resist pattern (500 nm holes, 1000 nm pitch).

[0367] <Evaluation> The sensitivity, depth of field, pattern circularity, and number of development defects of the resist patterns formed using the above-mentioned negative-type radiation-sensitive composition for KrF exposure were evaluated according to the following method. A scanning electron microscope (Hitachi High-Technologies Corporation's "CG-5000") was used to measure the length of the resist patterns. The results are shown in Table 5 below.

[0368] [Sensitivity] In forming a resist pattern using the above-mentioned negative-type radiation-sensitive composition for KrF exposure, the exposure amount used to form 500 nm holes and a 1000 nm pitch is defined as the optimal exposure amount, and this optimal exposure amount is defined as the sensitivity (mJ / cm²). ２ The sensitivity was set to 50 mJ / cm². ２ The following conditions are considered "good" and 50 mJ / cm². ２ If it exceeded this value, it was rated as "poor."

[0369] [Depth of Focus] In the resist pattern resolved at the optimal exposure amount determined in the sensitivity evaluation above, the dimensions were observed when the focus was changed in the depth direction. The margin in the depth direction where the pattern dimensions fall within 90% to 110% of the standard without bridging or residue was measured, and this measured value was defined as the depth of focus (nm). A larger depth of focus indicates a better result. A depth of focus of 300 nm or more is evaluated as "good," and a depth of focus of less than 300 nm is evaluated as "poor."

[0370] [Pattern Circularity] The 500 nm holes and 1000 nm pitch contact holes formed by irradiating with the optimal exposure amount determined in the sensitivity evaluation above were observed in plan view using the scanning electron microscope described above, and the vertical and horizontal sizes were measured. If the ratio of vertical size to horizontal size was 0.90 or more and 1.10 or less, it was evaluated as "A" (good), and if it was less than 0.90 or greater than 1.10, it was evaluated as "B" (poor).

[0371] [Development Defect Count] A resist film was exposed at the optimal exposure level to form a contact hole pattern with 500 nm holes and a 1000 nm pitch, and this was used as a wafer for defect inspection. The number of defects on this wafer was measured using a defect inspection device (KLA-Tencor's "KLA2810"). Defects with a diameter of 50 μm or less were judged to be originating from the resist film, and their number was calculated. After development, the number of defects judged to be originating from the resist film was evaluated as "good" if it was 100 or less, and as "poor" if it exceeded 100.

[0372]

[0373] As is clear from the results in Table 5, the radiation-sensitive composition of the example exhibited good sensitivity, depth of field, pattern circularity, and development defect performance when used in KrF negative exposure, whereas the comparative example did not satisfy all of these characteristics simultaneously. Therefore, when the radiation-sensitive composition of the example is used in KrF negative exposure, it is possible to form a resist pattern with optimal sensitivity and excellent roughness performance, pattern shape, and defect performance.

[0374] [Preparation of positive-type radiation-sensitive composition for extreme ultraviolet (EUV) exposure] [Example 55] A radiation-sensitive composition (J-55) was prepared by mixing 100 parts by mass of (A-7) as polymer (A), 30.0 parts by mass of (B-1) as first radiation-sensitive acid generator (B), 30.0 parts by mass of (C-8) as second radiation-sensitive acid generator (C), 40.0 parts by mass of (D-5) as acid diffusion control agent (D), and 6,800 parts by mass of a mixed solvent of (E-1) / (E-2) as solvent (E), and filtering the mixture through a membrane filter with a pore size of 0.2 μm.

[0375] [Examples 56-62, 104 and Comparative Examples 14-16] Radiation-sensitive compositions (J-56) to (J-62), (J-104), and (CJ-14) to (CJ-16) were prepared in the same manner as in Example 55, except that the components of the types and amounts shown in Table 6 below were used.

[0376]

[0377] <Formation of a resist pattern using a positive-type radiation-sensitive composition for EUV exposure> An anti-reflective underlayer film (ARC66 from Brewer Sciences) was applied to a 12-inch silicon wafer using a spin coater (CLEAN TRACK ACT12 from Tokyo Electron Limited), and then heated at 205°C for 60 seconds to form an anti-reflective underlayer film with an average thickness of 105 nm. The prepared positive-type radiation-sensitive composition for EUV exposure was applied to this anti-reflective underlayer film using the spin coater, and PB (plate blot) was performed at 130°C for 60 seconds. Subsequently, a resist film with an average thickness of 65 nm was formed by cooling at 23°C for 30 seconds. Next, the resist film was exposed using an EUV lithography system (ASML's "NXE3300") with NA = 0.33, illumination conditions: Conventional s = 0.89, and mask: imecDEFECT32FFR02. After exposure, PEB was performed at 120°C for 60 seconds. Subsequently, the resist film was alkaline developed using a 2.38 mass% TMAH aqueous solution as the alkaline developer, washed with water after development, and then dried to form a positive-type resist pattern (30 nm contact hole pattern).

[0378] <Evaluation> The sensitivity, CDU, and number of development defects of the resist patterns formed using the above-mentioned positive-type radiation-sensitive composition for EUV exposure were evaluated according to the following method. The results are shown in Table 7 below. A scanning electron microscope (Hitachi High-Technologies Corporation's "CG-5000") was used to measure the length of the resist patterns.

[0379] [Sensitivity] In forming a resist pattern using the above-mentioned positive-type radiation-sensitive composition for EUV exposure, the exposure amount used to form a 30 nm contact hole pattern is defined as the optimal exposure amount, and this optimal exposure amount is defined as the sensitivity (mJ / cm²). ２ The sensitivity was set to 40 mJ / cm². ２ In the following cases, it is considered "good" and 40 mJ / cm². ２ If it exceeded this value, it was rated as "poor."

[0380] [CDU] The mask size was adjusted to form a 30 nm contact hole pattern by irradiating with the optimal exposure amount determined in the sensitivity evaluation above, and a resist pattern was formed. The formed resist pattern was observed from the top of the pattern using the scanning electron microscope described above. The hole diameter was measured at 16 points in the range of 500 nm and the average value was calculated. This average value was measured at a total of 500 points at arbitrary points, and the 1 sigma value was calculated from the distribution of the measured values, and this was defined as the CDU performance (nm). The smaller the CDU performance value, the smaller the variation in hole diameter over long periods, and the better the performance. The CDU performance was evaluated as "good" if it was 2.0 nm or less, and as "poor" if it was greater than 2.0 nm.

[0381] [Development Defect Count] A 30 nm contact hole pattern was formed by exposing a resist film with the optimal exposure dose, and this was used as a wafer for defect inspection. The number of defects on this wafer for defect inspection was measured using a defect inspection device (KLA-Tencor's "KLA2810"). Defects with a diameter of 50 μm or less were judged to be originating from the resist film, and their number was calculated. After development, the defect count was evaluated as "good" if the number of defects judged to be originating from the resist film was 50 or less, and as "poor" if it exceeded 50.

[0382]

[0383] As is clear from the results in Table 7, the radiation-sensitive composition of the example showed good sensitivity, CDU, and development defect performance when used in EUV positive exposure, whereas the comparative example exhibited inferior characteristics compared to the example. Therefore, when the radiation-sensitive composition of the example is used in EUV positive exposure, it is possible to form a resist pattern with optimal sensitivity, excellent roughness performance, and superior defect performance.

[0384] [Preparation of negative-type radiation-sensitive composition for i-ray exposure] [Example 63] A radiation-sensitive composition (J-63) was prepared by mixing 100 parts by mass of (A-i-1) as a polymer (A), 2.0 parts by mass of (B-1) as a first radiation-sensitive acid generator (B), 1.0 part by mass of (C-2) as a second radiation-sensitive acid generator (C), 1.0 part by mass of (D-4) as an acid diffusion control agent (D), 15.0 parts by mass of (Q-1) as a crosslinking agent (Q), 20.0 parts by mass of (W-3) as other additives (W), and 250 parts by mass of a mixed solvent of (E-3) / (E-4) as a solvent (E), and filtering the mixture through a membrane filter with a pore size of 0.2 μm.

[0385] [Examples 64-69 and Comparative Examples 17-19] Radiation-sensitive compositions (J-64) to (J-69) and (CJ-17) to (CJ-19) were prepared in the same manner as in Example 63, except that the components of the types and amounts shown in Table 8 below were used.

[0386]

[0387] <Formation of a resist pattern using a negative-type radiation-sensitive composition for i-line lithography> The prepared negative-type radiation-sensitive composition for i-line lithography was applied to an 8-inch silicon wafer treated with hexamethyldisilazane using a spin coater (CLEAN TRACK ACT8 from Tokyo Electron Limited), and pre-bake (PB) was performed at 110°C for 60 seconds. Subsequently, a resist film with an average thickness of 4.3 μm was formed by cooling at 23°C for 30 seconds. Next, this resist film was exposed using an i-line lithography machine (Nikon 2205i14E2, wavelength 365 nm) under optical conditions of NA = 0.50 and σ = 0.60, via a mask pattern with 2.0 μm lines and 4.0 μm spaces. After exposure, post-exposure bake (PEB) was performed at 106°C for 60 seconds. Subsequently, the resist film was alkaline-developed using a 2.38% by mass aqueous solution of TMAH as the alkaline developer. After development, it was washed with water and then dried to form a negative-type resist pattern (2.0 μm lines, 4.0 μm spaces).

[0388] <Evaluation> The sensitivity, pattern rectangularity, exposure margin, and depth of field of the resist patterns formed using the above i-line exposure negative radiation-sensitive composition were evaluated according to the following method. A scanning electron microscope (Hitachi High-Technologies Corporation's "CS-4800") was used. The results are shown in Table 9 below.

[0389] [Sensitivity] In forming a resist pattern using the above i-line exposure negative-type radiation-sensitive composition, the exposure amount used to form a 2.0 μm line and a 4.0 μm space was defined as the optimal exposure amount, and this optimal exposure amount was defined as the sensitivity (msec). Sensitivity was evaluated as "good" if it was 200 msec or less, and as "poor" if it exceeded 200 msec.

[0390] [Pattern Rectangularity] The patterns of 2.0 μm lines and 4.0 μm spaces formed by irradiating with the optimal exposure amount determined in the sensitivity evaluation above were observed using the scanning electron microscope described above, and the cross-sectional shape of the line patterns was evaluated. The rectangularity of the resist pattern was evaluated as follows: if the difference between the length of the lower side and the length of the upper side in the cross-sectional shape of the line portion was 100 nm or less, it was evaluated as "A" (excellent); if it was between 100 nm and 200 nm, it was evaluated as "B" (good); and if it was greater than 200 nm, it was evaluated as "C" (poor).

[0391] [EL Performance (Exposure Margin)] Within the exposure range including the optimal exposure amount described above, resist patterns were formed by changing the exposure amount every 5 msec, and the CD of each pattern was measured using the scanning electron microscope described above. From the relationship between the obtained dimensions and exposure amount, the exposure amount E(1.9) at which the line dimension was 1.9 μm and the exposure amount E(2.1) at which the line width was 2.1 μm were determined, and the exposure margin (EL) was calculated using the formula: Exposure margin (EL) = (E(1.9) - E(2.1)) × 100 / (Optimal exposure amount). The larger the exposure margin value, the smaller the variation in the dimensions of the pattern obtained when the exposure amount is varied, and the higher the yield during device fabrication. EL performance was evaluated as "good" if it was 40% or more, and as "poor" if it was below 40%.

[0392] [Depth of Focus] In the resist pattern resolved at the optimal exposure amount determined in the sensitivity evaluation above, the dimensions were observed when the focus was changed in the depth direction. The margin in the depth direction where the pattern dimensions fall within 90% to 110% of the standard without bridging or residue was measured, and this measured value was defined as the depth of focus (nm). A larger depth of focus indicates a better result. A depth of focus of 2.0 μm or more is evaluated as "good," and a depth of focus of less than 2.0 μm is evaluated as "poor."

[0393]

[0394] As is clear from the results in Table 9, when the radiation-sensitive composition of the example was used in i-line negative exposure, it exhibited good sensitivity, exposure margin, depth of field, and pattern rectangularity, whereas in the comparative example, each of these characteristics was inferior to that of the example. Therefore, when the radiation-sensitive composition of the example is used in i-line negative exposure, it is possible to form a resist pattern with optimal sensitivity, excellent roughness performance, and superior pattern shape.

[0395] The radiation-sensitive composition and resist pattern formation method described above allow for the formation of resist patterns with good sensitivity to exposure light and excellent roughness performance, yield performance, pattern shape, and defect performance. Therefore, these can be suitably used in semiconductor device processing processes and the like, where further miniaturization is expected in the future.

Claims

Polymer (A) and, A primary radioactive acid generator (B) represented by the following formula (1), A secondary radioactive acid generator (C) that generates sulfonic acid (excluding those that fall under the category of the primary radioactive acid generator (B) above), Solvent (E) and A radiation-sensitive composition containing [a specific substance]. (In formula (1), X １ is -F, -Br, -I, or -CN. However, if n1 is 1, then X １ is -Br, -I, or -CN. X １ If there are multiple X １ They are either the same or different. 　 n1 is an integer between 1 and 5. However, X １ There are multiple X １ If all values ​​are -F, then n1 is an integer between 3 and 5. R １ is an alkyl group, -OCOR １１ , -COOR １２ , or -SO ２ R １３ . R １１ , R １２ , R １３ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. When there are a plurality of R １ , the plurality of R １ are the same or different from each other. However, R １ does not contain a polymerizable group. n2 is an integer between 0 and 5, where n1 + n2 ≤ 5. The above X １ If at least one of them is -I or -CN, then M １ ＋ This is an iodonium cation. (X above) １ However, in the case of -F or -Br, M １ ＋ This is a cation represented by the following formula (a). (In formula (a), Y is a halogen atom, a C2-C4 alkyl group, a C2-C4 alkoxy group, an alkyl halide, or -OCOR １４ , or -COOR １５ That is. R １４ , R １５ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. If multiple Ys exist, each Y is either identical or different. 　 Ar is an aromatic ring. R ２ It is a monovalent organic group. R ３ R is a methyl group, hydroxyl group, cyano group, nitro group, or acyl group. ３ If multiple R ３ They are either the same or different. 　 m1 is an integer between 1 and 5. m² is an integer between 0 and 5. 　 The radiation-sensitive composition according to claim 1, wherein the above Ar is a benzene ring. 　 The above R ２ The radiation-sensitive composition according to claim 1, wherein the group is represented by the following formula (i). (In formula (i), X ２ This includes halogen atoms, C2-C4 alkyl groups, C2-C4 alkoxy groups, halogenated alkyl groups, and -OCOR. ２１ , or -COOR ２２ That is. R ２１ , R ２２ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. a is either 0 or 1. b is an integer between 0 and (2a + 5). * represents the bond with iodine in equation (a). 　 The above Y is a halogen atom, a C2-C4 alkyl group, a C2-C4 alkoxy group, a C2-C4 halogenated alkyl group, or -OCOR １６ , or -COOR １７ (R １６ , R １７ The radiation-sensitive composition according to claim 1, wherein each is independently a hydrogen atom or a monovalent organic group having 2 to 4 carbon atoms. 　 The radiation-sensitive composition according to claim 1, wherein the second radiation-sensitive acid generator (C) is a compound comprising at least one cyclic structure. 　 The radiation-sensitive composition according to claim 1, wherein the second radiation-sensitive acid generator (C) is a compound represented by the following formula (2), the following formula (3), or the following formula (4). (In formula (2), R ４ It is a monovalent organic group having 1 to 40 carbon atoms. Z ２ ＋ (This is a monovalent organic cation.) (In formula (3), R ５ It is a monovalent organic group having 1 to 40 carbon atoms. R ６ If multiple R groups exist, each independently consists of a hydrogen atom, a nitro group, a hydroxyl group, a cyano group, a carboxyl group, a thiol group, a halogen atom, or a monovalent organic group, or two R groups. ６ These are divalent cyclic groups with 3 to 20 carbon atoms, formed by combining them with the carbon atoms to which they are bonded. t is an integer between 0 and 20. (W represents a ring structure with 5 to 8 members formed together with the carbon and nitrogen atoms to which it is bonded.) (In formula (4), R ７ These are, independently, monovalent organic groups having 1 to 20 carbon atoms. In the above formula (2), R ４ It includes at least one cyclic structure, SO ３ - The radiation-sensitive composition according to claim 6, wherein the group is a monovalent organic group having 3 to 40 carbon atoms, in which no fluorine atom or fluorinated hydrocarbon group is bonded to an atom adjacent to the sulfur atom in the group. 　 The radiation-sensitive composition according to any one of claims 1 to 7, wherein the polymer (A) comprises a structural unit (I) having a phenolic hydroxyl group. 　 The radiation-sensitive composition according to claim 8, further comprising a crosslinking agent (Q). 　 The radiation-sensitive composition according to claim 8, wherein the content of structural unit (I) in the total structural units constituting the polymer (A) is 20 mol% or more and 100 mol% or less. 　 The radiation-sensitive composition according to any one of claims 1 to 7, wherein the polymer (A) comprises a structural unit (III) having an acid-dissociable group. 　 The polymer (A) further comprises a structural unit (I) having a phenolic hydroxyl group, The radiation-sensitive composition according to claim 11, wherein the content of structural unit (I) in the total structural units constituting the polymer (A) is 20 mol% or more and 70 mol% or less. The above R １ However, -OCOR １１ or -SO ２ R １３ The radiation-sensitive composition according to any one of claims 1 to 7. 　 A radiation-sensitive composition according to any one of claims 1 to 7, further comprising an acid diffusion control agent (D). 　 A step of forming a resist film by directly or indirectly applying a radiation-sensitive composition according to any one of claims 1 to 7 to a substrate, The process of exposing the above-mentioned resist film, The process involves developing the exposed resist film with a developer solution. A pattern formation method, including the following. 　 The pattern formation method according to claim 15, wherein the above exposure is performed using an i-line, a KrF excimer laser, an ArF excimer laser, or extreme ultraviolet light. 　 A compound represented by the following formula (1'). (In formula (1'), X １１ is -I or -CN. However, X １１ If is -CN and n1 is 1, then X １１ SO ３ - It is located in the meta or ortho position relative to the group. １１ If there are multiple X １１ They are either the same or different. 　 n1 is an integer between 1 and 5. R １ is an alkyl group, -OCOR １１ ,-COOR １２ , or -SO ２ R １３ That is. R １１ , R １２ , R １３ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. １ If multiple R １ They are either the same or different. However, R １ It does not contain polymerizable groups. n2 is an integer between 0 and 5, where n1 + n2 ≤ 5. M ２ ＋ This is an iodonium cation.

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