Compounds and radiation-sensitive acid generators

Abstract

The present invention provides compounds and radiation-sensitive acid generators that can be used in radiation-sensitive resin compositions capable of exhibiting sufficient levels of sensitivity, LWR performance, and pattern rectangularity. [Solution] A compound represented by the following formula (1). JPEG2026065160000040.jpg39154

Description

[Technical Field]

[0001] This invention relates to compounds and radiation-sensitive acid generators. [Background technology]

[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 resin in alkaline or organic developers between the exposed and unexposed areas, thereby forming a resist pattern on the substrate.

[0003] The above-mentioned photolithography techniques utilize short-wavelength radiation such as ArF excimer lasers, and further employ liquid immersion lithography, a method in which exposure is performed with the space between the lens of the exposure apparatus and the resist film filled with a liquid medium, thereby promoting pattern miniaturization.

[0004] As efforts toward further technological advancements progress, a technique has been proposed to improve lithography performance by ArF exposure by incorporating a quencher (diffusion control agent) into the resist composition and capturing the acid that has diffused to the unexposed areas through a salt exchange reaction (Patent Document 1). Furthermore, as a next-generation technology, lithography using shorter wavelength radiation such as electron beams, X-rays, and EUV (extreme ultraviolet) is also being investigated. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 5556765 [Overview of the project] [Problems that the invention aims to solve]

[0006] In these efforts toward next-generation technologies, there is a demand for resist performance equivalent to or better than conventional methods in terms of sensitivity, line width roughness (LWR) performance (which indicates the variation in the line width of the resist pattern), and the rectangularity of the cross-sectional shape of the pattern (hereinafter also referred to as pattern rectangularity, etc.). However, existing radiation-sensitive resin compositions have not been able to achieve these properties at a sufficient level.

[0007] The present invention aims to provide a radiation-sensitive resin composition capable of exhibiting sufficient levels of sensitivity, LWR performance, pattern rectangularity, and the like, as well as a method for forming a pattern. [Means for solving the problem]

[0008] The inventors of this invention conducted extensive research to solve this problem and, as a result, found that the above objective can be achieved by adopting the following configuration, thus completing the present invention.

[0009] For example, in one embodiment, the present invention The compound represented by the following formula (1) (hereinafter also referred to as "compound (1)"), [ka] (In formula (1), R f This is a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms. R 1 and R 2 Each of these is independently a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, a fluorine atom, or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms. L 1 This is either -COO- or -OCO-. A 1 These are single bonds, methylene groups, and linear alkylene groups with 2 to 40 carbon atoms. L 2 These are -O-, -COO-, -OCO-, -S-, -NR-, -NRCO-, or -CONR-. R represents a hydrogen atom or an organic group with 1 to 10 carbon atoms. A 2is a methyl group or a linear alkyl group having 2 to 40 carbon atoms. n1 is an integer from 0 to 4. When n1 is 2 or more, a plurality of R f and R 1 are the same as or different from each other. n2 is an integer from 0 to 6. When n2 is 2 or more, a plurality of R 2 are the same as or different from each other. However, the sum of n1 and n2 is an integer of 1 or more. n3 is an integer from 0 to 10. When n3 is 2 or more, a plurality of [-L 2 -A 1 -] are the same as or different from each other. However, the total number of carbon atoms of all A 1 and A 2 is 6 or more. Z1 + is a monovalent radiation-sensitive onium cation. ) a resin containing a structural unit having an acid dissociable group, one or more compounds represented by the following formula (2) or (3) (however, excluding the compound represented by the above formula (1). Hereinafter, these are also referred to as "compound (2)" and "compound (3)"),

Chemical formula

[0010] The radiation-sensitive resin composition of the present invention contains compound (1) as a radiation-sensitive acid generator, thereby enabling it to exhibit excellent sensitivity, LWR performance, and pattern rectangularity during resist pattern formation. Compound (1) is presumed to be primarily located on the bottom side of the resist film due to its long-chain structure, and thus contributes to the improvement of pattern rectangularity, as well as excellent sensitivity and LWR performance. However, this presumption of the mechanism of action does not necessarily limit the scope of the present invention.

[0011] In the present invention, examples of organic groups include monovalent hydrocarbon groups, groups containing a divalent heteroatom-containing group between carbon atoms of the hydrocarbon group, and groups in which some or all of the hydrogen atoms contained in the hydrocarbon group and the group containing the divalent heteroatom-containing group are replaced with monovalent heteroatom-containing groups.

[0012] In the present invention, unless otherwise specified, the term "hydrocarbon group" includes linear hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. The term "hydrocarbon group" includes both saturated hydrocarbon groups and unsaturated hydrocarbon groups. The term "linear hydrocarbon group" refers to a hydrocarbon group that does not contain a cyclic structure and is composed only of a linear structure, and includes both straight-chain hydrocarbon groups and branched-chain hydrocarbon groups. The term "alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic structure as its ring structure and does not contain an aromatic ring structure, and includes both monocyclic alicyclic hydrocarbon groups and polycyclic alicyclic hydrocarbon groups. However, it is not necessary for it to be composed only of an alicyclic structure, and it may contain a linear structure as part of it. The term "aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as its ring structure. However, it is not necessary for it to be composed only of an aromatic ring structure, and it may contain a linear structure or an alicyclic structure as part of it.

[0013] On the other hand, in another embodiment, the present invention states that (1) A step of applying the above radiation-sensitive resin composition directly or indirectly onto a substrate to form a resist film. (2) A step of exposing the above-mentioned resist film, and The present invention relates to a method for forming a resist pattern, which includes a step (3) of developing the exposed resist film.

[0014] Since the method for forming a resist pattern of the present invention includes a step using the above-mentioned radiation-sensitive resin composition, it can be used to form a good pattern with excellent sensitivity, LWR performance, pattern rectangularity, and other properties. [Modes for carrying out the invention]

[0015] The embodiments of the present invention will be described in detail below, but the present invention is not limited to these embodiments.

[0016] <Radiation sensitive resin composition> The radiation-sensitive resin composition according to this embodiment (hereinafter also simply referred to as "the composition") comprises a predetermined compound (1), a resin containing a structural unit having an acid-dissociable group, one or more compounds represented by the above formula (2) or (3), and a solvent. The above composition may contain other optional components as long as they do not impair the effects of the present invention. By containing the predetermined compound (1), the radiation-sensitive resin composition can be given a high level of sensitivity, LWR performance, and pattern rectangularity.

[0017] (The compound represented by formula (1)) The radiation-sensitive resin composition of the present invention contains a compound represented by the above formula (1).

[0018] In the above formula (1), the above R f Examples of monovalent fluorinated hydrocarbon groups having 1 to 10 carbon atoms, as represented by this formula, include monovalent fluorinated linear hydrocarbon groups having 1 to 10 carbon atoms and monovalent fluorinated alicyclic hydrocarbon groups having 3 to 10 carbon atoms.

[0019] Examples of the above monovalent fluorinated chain hydrocarbon groups having 1 to 10 carbon atoms include: Fluorinated alkyl groups such as trifluoromethyl group, 2,2,2-trifluoroethyl group, pentafluoroethyl group, 2,2,3,3,3-pentafluoropropyl group, 1,1,1,3,3,3-hexafluoropropyl group, and heptafluoron-propyl group; Fluorinated alkenyl groups such as trifluoroethenyl groups and pentafluoropropenyl groups; Examples include fluorinated alkynyl groups such as fluoroethynyl groups and trifluoropropynyl groups.

[0020] Examples of the above-mentioned monovalent fluorinated alicyclic hydrocarbon groups having 3 to 10 carbon atoms include: Fluorinated cycloalkyl groups such as fluorocyclopentyl group, difluorocyclopentyl group, nonafluorocyclopentyl group, fluorocyclohexyl group, difluorocyclohexyl group, undecafluorocyclohexylmethyl group, fluoronorbornyl group, fluoroadamantyl group, fluorobornyl group, and fluoroisobornyl group; Examples include fluorinated cycloalkenyl groups such as fluorocyclopentenyl groups and nonafluorocyclohexenyl groups.

[0021] The above-mentioned fluorinated hydrocarbon group is preferably a monovalent fluorinated linear hydrocarbon group having 1 to 10 carbon atoms, more preferably a monovalent fluorinated alkyl group having 1 to 8 carbon atoms, even more preferably a perfluoroalkyl group having 1 to 6 carbon atoms, and particularly preferably a linear perfluoroalkyl group having 1 to 6 carbon atoms.

[0022] In the above formula (1), the above R 1 and R 2 The monovalent hydrocarbon group having 1 to 10 carbon atoms represented by is not particularly limited, and examples include monovalent linear hydrocarbon groups having 1 to 10 carbon atoms, monovalent alicyclic hydrocarbon groups having 3 to 10 carbon atoms, and monovalent aromatic hydrocarbon groups having 6 to 10 carbon atoms.

[0023] The above R 1 and R 2Examples of the monovalent chain hydrocarbon group having 1 to 10 carbon atoms represented by the above formula include a straight-chain or branched-chain saturated hydrocarbon group having 1 to 10 carbon atoms, or a straight-chain or branched-chain unsaturated hydrocarbon group having 1 to 10 carbon atoms.

[0024] The above R 1 and R 2 Examples of monovalent alicyclic hydrocarbon groups having 3 to 10 carbon atoms, as represented above, include monocyclic or polycyclic saturated hydrocarbon groups, or monocyclic or polycyclic unsaturated hydrocarbon groups. Preferred monocyclic saturated hydrocarbon groups include, for example, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. Preferred polycyclic cycloalkyl groups include, for example, bridged alicyclic hydrocarbon groups such as norbornyl and adamantyl 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 groups. A bridged alicyclic hydrocarbon group refers to a polycyclic alicyclic hydrocarbon group in which two carbon atoms constituting the alicyclic ring that are not adjacent to each other are bonded together by a bond chain containing one or more carbon atoms.

[0025] The above R 1 and R 2 Examples of the above-mentioned monovalent aromatic hydrocarbon groups having 6 to 10 carbon atoms include aryl groups such as phenyl, tolyl, xyl, naphthyl, and anthyl groups; and aralkyl groups such as benzyl, phenethyl, and naphthylmethyl groups.

[0026] The above R 1 ~R 2 As a cyclic structure with 3 to 10 carbon atoms formed when two of these are combined with each other and bonded together with the carbon atom, one example is a structure obtained by removing one more hydrogen atom from the above-mentioned monovalent alicyclic hydrocarbon group with 3 to 10 carbon atoms.

[0027] The above R 1 and R2 As a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms, R f This is similar to a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms, represented by [formula].

[0028] In the above formula (1), the above L 1 This is either -COO- or -OCO-.

[0029] In the above formula (1), A 1 The linear alkylene group having 2 to 40 carbon atoms represented by this formula is not particularly limited.

[0030] In the above formula (1), the above L 2 These are -O-, -COO-, -OCO-, -S-, -NR-, -NRCO-, or -CONR-. R represents a hydrogen atom or an organic group with 1 to 10 carbon atoms.

[0031] In the above formula (1), A 2 The linear alkyl group having 2 to 40 carbon atoms represented by is not particularly limited.

[0032] In equation (1) above, n1 is an integer from 0 to 4. If n1 is 2 or greater, multiple R f and R 1 They are either identical or different from one another.

[0033] In equation (1) above, n2 is an integer from 0 to 6. If n2 is 2 or greater, multiple R 2 They are either identical or different from each other. Furthermore, the sum of n1 and n2 is an integer greater than or equal to 1.

[0034] In the above formula (1), n3 is an integer between 0 and 10. If n3 is 2 or greater, multiple [-L 2 -A 1 -] are either identical or different from each other. However, all A 1 and A 2 The total number of carbon atoms is 6 or more, preferably 8 or more, more preferably 10 or more, preferably 40 or less, and even more preferably 30 or less.

[0035] In the above formula (1), Z1 + Examples of monovalent radiosensitive onium cations represented by the formulas (X-1) to (X-6) below include radiodegradable onium cations containing elements such as S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, and Bi. Examples include sulfonium cations, tetrahydrothiophenium cations, iodonium cations, phosphonium cations, diazonium cations, and pyridinium cations. Among these, sulfonium cations or iodonium cations are preferred. Sulfonium cations or iodonium cations are preferably represented by the following formulas (X-1) to (X-6).

[0036] [ka]

[0037] [ka]

[0038] [ka]

[0039] [ka]

[0040] [ka]

[0041] [ka]

[0042] In the above equation (X-1), R a1 , R a2 and R a3Each 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 having 6 to 12 carbon atoms, a hydroxyl group, a halogen atom, and -OSO2-R. P , -SO2-R Q Alternatively, -SR T This represents a ring structure formed by combining two or more of these groups. This ring structure may contain heteroatoms such as O or S between the carbon-carbon bonds that form 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. a1 ~R a3 R P , R Q and R T If each of them is multiple, then multiple R a1 ~R a3 R P , R Q and R T These may be the same or different.

[0043] 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, 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 is 1, k4 is an integer from 0 to 7. b1 If there are multiple, then multiple R b1 They may be the same or different, and there may be multiple R b1may represent a ring structure configured to fit together with each other. R b2 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. L C is a single bond or a divalent linking group. k5 is an integer from 0 to 4. R b2 When there are a plurality of R b2 they may be the same or different, and a plurality of R b2 may represent a ring structure configured to fit together with each other. q is an integer from 0 to 3. In the formula, S + The ring structure containing may contain heteroatoms such as O or S between the carbon-carbon bonds forming the skeleton.

[0044] In the above formula (X-3), R c1 , R c2 and R c3 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms.

[0045] In the above formula (X-4), R g1 is a substituted or unsubstituted linear or branched alkyl group 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 hydroxy group. n k is 0 or 1. n k2 When n k2 is 0, k10 is an integer from 0 to 4, and when n g1 is 1, k10 is an integer from 0 to 7. R g1 When there are a plurality of R g1 they may be the same or different, and a plurality of R g2 and R g3is, independently of each other, 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 having 6 to 12 carbon atoms, a hydroxy group, a halogen atom, or represents a ring structure formed by combining these groups with each other. k11 and k12 are each independently an integer of 0 to 4. R g2 and R g3 When there are a plurality of each of R g2 and R g3 may be the same or different from each other.

[0046] In the above formula (X-5), R d1 and R d2 are, independently of each other, a substituted or unsubstituted linear or branched alkyl group, alkoxy group or alkoxycarbonyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, a halogen atom, a halogenated alkyl group having 1 to 4 carbon atoms, a nitro group, or represents a ring structure formed by combining two or more of these groups with each other. k6 and k7 are each independently an integer of 0 to 5. R d1 and R d2 When there are a plurality of each of R d1 and R d2 may be the same or different from each other.

[0047] In the above formula (X-6), R e1 and R e2 are, independently of each other, a halogen atom, a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k8 and k9 are each independently an integer of 0 to 4.

[0048] The above compound (1) is formed by any combination of the anionic moiety defined by formula (1) and the monovalent radiation-sensitive onium cation. Specific examples of the above compound (1) are not limited to those represented by the following formulas (B-1) to (B-19).

[0049] [ka]

[0050] [ka]

[0051] [ka]

[0052] The content of compound (1) in this embodiment (the total of multiple compounds in the case of combined use) is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, even more preferably 0.1 parts by mass or more, and particularly preferably 0.5 parts by mass or more, per 100 parts by mass of resin containing the acid-dissociable structural unit described later. Furthermore, it is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less. The content of compound (1) is appropriately selected depending on the type of resin used, the exposure conditions and the required sensitivity, and the type and content of compound (2) and compound (3) described later. This enables excellent sensitivity, LWR performance, and pattern rectangularity during resist pattern formation.

[0053] Compound (1) is a component that generates acid upon exposure. The acid generated upon exposure is thought to perform two functions in the radiation-sensitive resin composition, depending on its strength. The first function is that the acid generated by exposure dissociates the acid-dissociable groups of the polymer, generating carboxyl groups and other components. (An acid generator having this first function is also called "acid generator (I).") The second function is to substantially prevent the acid-dissociable groups of the polymer from dissociating under pattern-forming conditions using a radiation-sensitive resin composition, thereby suppressing the diffusion of acid generated from the acid generator (I) in the unexposed areas. (An acid generator having this second function is also called an "acid diffusion control agent" or "acid generator (II).") The acid generated from acid generator (II) is a relatively weaker acid (an acid with a higher pKa) than the acid generated from acid generator (I). Whether an acid generator functions as acid generator (I) or acid generator (II) depends on the energy required for the dissociation of the acid-dissociable group and the thermal energy conditions applied when forming a pattern using the radiation-sensitive resin composition. Generally, however, those with a structure in which a halogen atom is located near the sulfonic acid anion, i.e., n1 in formula (1) above is 1 or greater, and R f and R 1 Compounds in which the atom is a fluorine atom or a fluorinated hydrocarbon group tend to function as acid generators (I).

[0054] (One or more compounds represented by formula (2) or (3)) The radiation-sensitive resin composition of the present invention comprises one or more compounds represented by the following formula (2) or (3). Any matters not described for compound (2) and compound (3) shall be as appropriate, in accordance with the description for compound (1). [ka] (In equations (2) and (3), R 3 and R 4 Each of these independently represents either a monovalent organic group having 1 to 50 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. R 5 This is a hydrogen atom or a monovalent organic group having 1 to 50 carbon atoms. R 6 This is a hydrogen atom or a monovalent organic group having 1 to 50 carbon atoms. Z2 + and Z3 +These are, independently, monovalent, radiation-sensitive onium cations.

[0055] In the above formula (2), the above R 3 and R 4 Examples of monovalent organic groups having 1 to 50 carbon atoms represented by this formula include monovalent hydrocarbon groups having 1 to 50 carbon atoms, groups containing a divalent heteroatom-containing group between carbon atoms of the hydrocarbon group, and groups in which some or all of the hydrogen atoms in the hydrocarbon group and the group containing the divalent heteroatom-containing group are replaced with monovalent heteroatom-containing groups.

[0056] The above R 3 and R 4 Examples of monovalent hydrocarbon groups having 1 to 50 carbon atoms, represented by this formula, include chain hydrocarbon groups having 1 to 50 carbon atoms, monovalent alicyclic hydrocarbon groups having 3 to 50 carbon atoms, and monovalent aromatic hydrocarbon groups having 6 to 50 carbon atoms.

[0057] The above R 3 and R 4 Examples of chain-like hydrocarbon groups having 1 to 50 carbon atoms represented by this formula include straight-chain or branched-chain saturated hydrocarbon groups having 1 to 50 carbon atoms, or straight-chain or branched-chain unsaturated hydrocarbon groups having 1 to 50 carbon atoms.

[0058] The above R 3 and R 4Examples of alicyclic hydrocarbon groups having 3 to 50 carbon atoms, represented by , include monocyclic or polycyclic saturated hydrocarbon groups, or monocyclic or polycyclic unsaturated hydrocarbon groups. Preferred monocyclic saturated hydrocarbon groups include, for example, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. Preferred polycyclic cycloalkyl 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 in the alicyclic ring are bonded together by a bond chain that includes one or more carbon atoms.

[0059] The above R 3 and R 4 Examples of monovalent aromatic hydrocarbon groups having 6 to 50 carbon atoms, represented by , include aryl groups such as phenyl, tolyl, xyl, naphthyl, and anthyl groups; and aralkyl groups such as benzyl, phenethyl, and naphthylmethyl groups.

[0060] In the above formula (2), the above R 3 and R 4 The hydrocarbon group represented above, which includes a divalent heteroatom-containing group between the carbon atoms, is not particularly limited as long as it includes a divalent heteroatom-containing group, such as an oxygen atom or a sulfur atom, between the carbon atoms of the hydrocarbon group.

[0061] In the above formula (2), the above R 3 and R 4 The group is not particularly limited as long as some or all of the hydrogen atoms in the group containing the above-mentioned divalent heteroatom-containing group are replaced with a monovalent heteroatom-containing group, such as a fluorine atom or a chlorine atom.

[0062] In the above formula (2), the above R 3 and R 4 The divalent alicyclic groups having 3 to 20 carbon atoms, formed by combining these groups with the carbon atoms to which they are bonded, are not particularly limited as long as they are groups obtained by removing two hydrogen atoms from the same carbon atom constituting the carbon ring of a monocyclic or polycyclic alicyclic hydrocarbon of the above number of carbon atoms.

[0063] In the above formula (2), the above R 5 The monovalent organic group having 1 to 50 carbon atoms, represented by the above R 3 and R 4 The above R 5 For example, hydrogen can be given as a preferred example.

[0064] In the above formula (3), the above R 6 R is a hydrogen atom or a monovalent organic group having 1 to 50 carbon atoms. 6 The monovalent organic group having 1 to 50 carbon atoms, represented by the above R 3 and R 4 It is equivalent to the following.

[0065] In equations (2) and (3) above, Z2 + and Z3 + These are, independently, monovalent, radiation-sensitive onium cations. (See Z2 above) + and Z3 + The monovalent radiation-sensitive onium cation represented by the above Z1 + It is equivalent to the following.

[0066] It is preferable that compounds (2) and (3) above can function as the acid generator (II) described above. That is, it is preferable that compounds (2) and (3) above are radiation-sensitive acid generators that generate an acid with a higher pKa than the acid generated from compound (1), i.e., a relatively weak acid.

[0067] Compounds (2) and (3) described above are formed by any combination of the anionic moiety defined by formula (2) or formula (3) and the monovalent radiation-sensitive onium cation described above. Specific examples of compounds (2) and (3) described above are not limited to those described above, but include structures represented by the following formulas (C-1) to (C-5).

[0068] [ka]

[0069] The lower limit of the content of compound (2) and compound (3) (or the total amount if multiple compounds are used in combination) is preferably 3 parts by mass, more preferably 4 parts by mass, and even more preferably 5 parts by mass, per 100 parts by mass of compound (1) (or the total amount if multiple compounds are used in combination). The upper limit of the content is preferably 150 parts by mass, more preferably 120 parts by mass, and even more preferably 110 parts by mass.

[0070] The content of compound (2) and compound (3) in the radiation-sensitive resin composition according to this embodiment (the total amount if multiple types of compounds are used in combination) is preferably 0.01 parts by mass or more and 30 parts by mass or less per 100 parts by mass of the resin described later. The content is more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less. Furthermore, 0.05 parts by mass or more is more preferably, even more preferably 0.1 parts by mass or more, and particularly preferably 0.5 parts by mass or more. The content of compound (2) and compound (3) is appropriately selected depending on the type of resin used, the exposure conditions and the required sensitivity, and the type and content of compound (1). This makes it possible to exhibit excellent sensitivity, LWR performance and pattern rectangularity when forming a resist pattern.

[0071] (Resin containing structural units with acid-dissociable groups) A resin containing an acid-dissociable structural unit is an aggregate of polymers having an acid-dissociable structural unit (hereinafter also referred to as "structural unit (I)") (hereinafter this resin is also referred to as the "base resin"). An "acid-dissociable group" is a hydrogen atom-substituting group such as a carboxyl group, phenolic hydroxyl group, alcoholic hydroxyl group, or sulfo group, which dissociates upon the action of an acid. The radiation-sensitive resin composition of the present invention exhibits excellent pattern-forming properties because the above resin contains structural unit (I).

[0072] The base resin preferably has structural unit (II) in addition to structural unit (I), which includes at least one selected from the group consisting of lactone structures, cyclic carbonate structures, and sultone structures, as described later, and may also have other structural units other than structural units (I) and (II). Each structural unit will be described below. For matters not described above as resin, the description will be made in accordance with the description of compound (1), etc.

[0073] [Structural Unit (I)] Structural unit (I) is a structural unit containing an acid-dissociable group. Structural unit (I) is not particularly limited as long as it contains an acid-dissociable group, and examples include structural units having a tertiary alkyl ester moiety, structural units having a structure in which the hydrogen atom of a phenolic hydroxyl group is replaced by a tertiary alkyl group, structural units having an acetal bond, etc. However, from the viewpoint of improving pattern formation, structural units represented by the following formula (4) (hereinafter also referred to as "structural unit (I-1)") or structural units represented by the following formula (5) (hereinafter also referred to as "structural unit (I-2)") are preferred.

[0074] [ka] (In equations (4) and (5), R 7 These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 8 It is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R 9 and R 10Each of these independently represents either a monovalent linear hydrocarbon group having 1 to 10 carbon atoms or a monovalent monocyclic aliphatic hydrocarbon group having 3 to 6 carbon atoms, or a divalent monocyclic aliphatic hydrocarbon group having 3 to 6 carbon atoms formed by combining these groups with the carbon atoms to which they are bonded. R 11 and R 12 Each of them is independent of R 11 is a monovalent linear hydrocarbon group having 1 to 10 carbon atoms, a monovalent bridged alicyclic hydrocarbon group having 6 to 20 carbon atoms, or a monovalent monocyclic aliphatic hydrocarbon group having 7 to 10 carbon atoms, and R 12 This represents a monovalent bridged alicyclic hydrocarbon group having 6 to 20 carbon atoms or a monovalent monocyclic aliphatic hydrocarbon group having 7 to 10 carbon atoms, or a divalent bridged alicyclic hydrocarbon group having 6 to 20 carbon atoms or a divalent monocyclic aliphatic hydrocarbon group having 7 to 10 carbon atoms formed by combining these groups with the carbon atoms to which they are bonded.

[0075] In equations (4) and (5) above, the above R 7 From the viewpoint of copolymerization of monomers that give structural unit (I-1) and structural unit (I-2), hydrogen atoms and methyl groups are preferred, and methyl groups are more preferred.

[0076] In equations (4) and (5) above, the above R 8 Examples of monovalent hydrocarbon groups having 1 to 20 carbon atoms, represented by this formula, include chain hydrocarbon groups having 1 to 10 carbon atoms, monovalent alicyclic hydrocarbon groups having 3 to 10 carbon atoms, and monovalent aromatic hydrocarbon groups having 6 to 10 carbon atoms.

[0077] In the above formula (4), the above R 9 and R 10 Examples of chain-like hydrocarbon groups having 1 to 10 carbon atoms represented by this formula include linear or branched saturated hydrocarbon groups having 1 to 10 carbon atoms, or linear or branched unsaturated hydrocarbon groups having 1 to 10 carbon atoms.

[0078] In the above formula (4), the above R 9 and R 10As a monovalent monocyclic aliphatic hydrocarbon group having 3 to 6 carbon atoms, for example, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups are preferred.

[0079] In the above formula (4), the above R 9 and R 10 The divalent monocyclic aliphatic hydrocarbon group having 3 to 6 carbon atoms, formed by combining these groups with the carbon atoms to which they are bonded, is not particularly limited as long as it is a group obtained by removing two hydrogen atoms from the same carbon atom constituting the carbon ring of the alicyclic hydrocarbon of the above number of carbon atoms.

[0080] In the above formula (5), the above R 11 Examples of monovalent linear hydrocarbon groups having 1 to 10 carbon atoms represented by this formula include linear or branched saturated hydrocarbon groups having 1 to 10 carbon atoms, or linear or branched unsaturated hydrocarbon groups having 1 to 10 carbon atoms.

[0081] In the above formula (5), the above R 11 Examples of monovalent bridged alicyclic hydrocarbon groups having 6 to 20 carbon atoms, represented by [the formula], include norbornyl, adamantyl, tricyclodecyl, and tetracyclododecyl groups.

[0082] In the above formula (5), the above R 11 Examples of monovalent monocyclic aliphatic hydrocarbon groups having 7 to 10 carbon atoms, represented by , include cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups.

[0083] In the above formula (5), the above R 12 Examples of monovalent bridged alicyclic hydrocarbon groups having 6 to 20 carbon atoms, represented by [the formula], include norbornyl, adamantyl, tricyclodecyl, and tetracyclododecyl groups.

[0084] In the above formula (5), the above R 12Examples of monovalent monocyclic aliphatic hydrocarbon groups having 7 to 10 carbon atoms, represented by , include cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups.

[0085] In the above formula (5), the above R 11 and R 12 The groups represented by these are combined with the carbon atoms to which they are bonded, forming a divalent bridged alicyclic hydrocarbon group having 6 to 20 carbon atoms or a divalent monocyclic aliphatic hydrocarbon group having 7 to 10 carbon atoms. These groups are not particularly limited as long as they are formed by removing two hydrogen atoms from the same carbon atom constituting the carbon ring of the hydrocarbon with the above number of carbon atoms.

[0086] Examples of structural units (I-1) and (I-2) include the structural units represented by the following formulas (4-1) to (4-5) (hereinafter also referred to as "structural units (I-1-1) to (I-1-5)").

[0087] [ka]

[0088] In the above equations (4-1) to (4-5), R 7 ~R 10 This is equivalent to equation (4) above. i and j are independent integers between 1 and 2. l is 0 or 1.

[0089] i and j are preferably 1. 8 A methyl group, an ethyl group, or an isopropyl group is preferred. 9 and R 10 A methyl group or an ethyl group is preferred.

[0090] Examples of structural units (I-2) include the structural units represented by the following formulas (5-1) to (5-6) (hereinafter also referred to as "structural units (I-2-1) to (I-2-6)").

[0091] [ka]

[0092] In the above equations (5-1) to (5-6), R 7 ~R 12 This is equivalent to equation (5) above. i' and j' are independent integers between 3 and 6. k' is between 0 and 2.

[0093] i' and j' are preferably 1. 8 A methyl group, an ethyl group, or an isopropyl group is preferred.

[0094] The base resin may contain one or more structural units (I) in combination.

[0095] The content of structural unit (I) (total content if multiple types are included) is preferably 10 mol% or more, more preferably 20 mol% or more, even more preferably 30 mol% or more, and particularly preferably 35 mol% or more, relative to the total structural units constituting the base resin. Furthermore, it is preferably 80 mol% or less, more preferably 75 mol% or less, even more preferably 70 mol% or less, and particularly preferably 65 mol% or less. By setting the content of structural unit (I) within the above range, the pattern-forming properties of the radiation-sensitive resin composition of the present invention can be further improved.

[0096] [Structural Units (II)] Structural unit (II) is a structural unit comprising at least one selected from the group consisting of lactone structures, cyclic carbonate structures, and sultone structures. By further comprising structural unit (II), the solubility of the base resin in the developer can be adjusted, and as a result, the lithography performance, such as resolution, of the resist film obtained from the radiation-sensitive resin composition of the present invention can be improved. Furthermore, the adhesion between the resist pattern formed from the base resin and the substrate can be improved.

[0097] Examples of structural units (II) include those represented by the following formulas (T-1) to (T-10).

[0098] [ka]

[0099] 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, and a dimethylamino group. L4 and R L5 These may be divalent alicyclic groups having 3 to 8 carbon atoms, which can be combined with each other and formed together with the carbon atoms to which they are bonded. 2 is 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.

[0100] The above R L4 and R L5 When these are combined with each other, the divalent alicyclic group having 3 to 8 carbon atoms, formed together with the carbon atoms to which they are bonded, is R in formula (5) above. 11 and R 12 Examples include divalent alicyclic groups with 3 to 8 carbon atoms, which are formed by combining chain-like hydrocarbon groups or alicyclic hydrocarbon groups represented by the formula, together with the carbon atoms to which they are bonded. One or more hydrogen atoms on this alicyclic group may be substituted with hydroxyl groups.

[0101] 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-.

[0102] Among these, structural units (II) are preferably those containing a lactone structure, more preferably those containing a norbornane lactone structure, and even more preferably those derived from norbornane lactone-yl (meth)acrylate.

[0103] The content of structural unit (II) is preferably 20 mol% or more, more preferably 25 mol% or more, and even more preferably 30 mol% or more, relative to the total structural units constituting the base resin. Furthermore, it is preferably 80 mol% or less, more preferably 75 mol% or less, and even more preferably 70 mol% or less. By setting the content of structural unit (II) within the above range, the lithography performance, such as the resolution of the resist film obtained from the radiation-sensitive resin composition of the present invention, and the adhesion of the formed resist pattern to the substrate can be further improved.

[0104] [Structural Unit (III)] The base resin may optionally contain other structural units in addition to the above-mentioned structural units (I) and (II). Examples of these other structural units include structural unit (III) containing a polar group (excluding those corresponding to structural unit (II)). By further containing structural unit (III), the solubility of the base resin in the developer can be adjusted, and as a result, the lithography performance, such as resolution, of the resist film obtained from the radiation-sensitive resin composition of the present invention can be improved. Examples of these polar groups include hydroxyl groups, carboxyl groups, cyano groups, nitro groups, sulfonamide groups, etc. Among these, hydroxyl groups and carboxyl groups are preferred, and hydroxyl groups are more preferred.

[0105] Examples of structural units (III) include structural units represented by the following formula.

[0106] [ka]

[0107] In the above formula, R AThis is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0108] When the base resin has structural unit (III) having the polar group, the content of structural unit (III) is preferably 5 mol% or more, more preferably 8 mol% or more, and even more preferably 10 mol% or more, relative to the total structural units constituting the base resin. Furthermore, it is preferably 40 mol% or less, more preferably 35 mol% or less, and even more preferably 30 mol% or less.

[0109] [Structural Units (IV)] The base resin may optionally contain structural units other than the polar group-containing structural unit (III) described above, such as structural units derived from hydroxystyrene or structural units containing phenolic hydroxyl groups (hereinafter, both are collectively referred to as "structural unit (IV)"). Structural unit (IV) contributes to improved etching resistance and improved difference in developer solubility between exposed and unexposed areas (dissolution contrast). In particular, it can be suitably applied to pattern formation using exposure with radiation of wavelengths of 50 nm or less, such as electron beams and EUV. In this case, it is preferable that the resin contains structural unit (I) along with structural unit (IV).

[0110] In this case, it is preferable to polymerize the phenolic hydroxyl group while protecting it with a protecting group such as an alkali-dissociable group, and then deprotect it by hydrolysis to obtain structural unit (IV). The structural unit that gives structural unit (IV) by hydrolysis is preferably represented by the following formulas (6-1) and (6-2).

[0111] [ka]

[0112] In the above equations (6-1) and (6-2), R 13 R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 12 R is a monovalent hydrocarbon group or alkoxy group having 1 to 20 carbon atoms.14 As monovalent hydrocarbon groups with 1 to 20 carbon atoms, R in structural unit (I) 8 Examples of monovalent hydrocarbon groups having 1 to 20 carbon atoms include alkoxy groups such as methoxy, ethoxy, and tert-butoxy groups.

[0113] The above R 14 Preferably, alkyl groups and alkoxy groups are used, with methyl groups and tert-butoxy groups being more preferred.

[0114] For resins used for exposure with radiation of wavelength 50 nm or less, the content of structural unit (IV) is preferably 10 mol% or more, more preferably 20 mol% or more, relative to the total structural units constituting the resin. Furthermore, it is preferably 70 mol% or less, and more preferably 60 mol% or less.

[0115] (Method of synthesizing the base resin) The base resin can be synthesized, for example, by polymerizing monomers that provide each structural unit in a suitable solvent using a radical polymerization initiator or the like.

[0116] 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, with AIBN being more preferred. These radical initiators can be used individually or in combination of two or more.

[0117] Examples of solvents used in the polymerization described above 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; Ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone, and 2-heptanone; Ethers such as tetrahydrofuran, dimethoxyethanes, and diethoxyethanes; Examples of solvents include methanol, ethanol, 1-propanol, 2-propanol, 4-methyl-2-pentanol, and other alcohols. The solvent used in these polymerizations may be used alone or in combination of two or more.

[0118] The reaction temperature in the polymerization described above is typically 40°C to 150°C, with 50°C to 120°C being preferred. The reaction time is typically 1 hour to 48 hours, with 1 hour to 24 hours being preferred.

[0119] The molecular weight of the base resin is not particularly limited, but a polystyrene-equivalent weight-average molecular weight (Mw) of 1,000 to 50,000 as determined by gel permeation chromatography (GPC) is preferably 2,000 to 30,000, even more preferably 3,000 to 15,000, and particularly preferably 4,000 to 12,000. If the Mw of the base resin is below the lower limit, the heat resistance of the resulting resist film may decrease. If the Mw of the base resin exceeds the upper limit, the developability of the resist film may decrease.

[0120] The ratio of Mw (Mw / Mn) to the polystyrene-equivalent number-average molecular weight (Mn) of the base resin, calculated by GPC, is usually between 1 and 5, preferably between 1 and 3, and more preferably between 1 and 2.

[0121] In this specification, the Mw and Mn values ​​of the resin are measured using gel permeation chromatography (GPC) under the following conditions.

[0122] GPC columns: 2 x G2000HXL, 1 x G3000HXL, 1 x G4000HXL (all manufactured by Tosoh) Column temperature: 40℃ Leaching solvent: Tetrahydrofuran Flow rate: 1.0mL / min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0123] The base resin content is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 85% by mass or more, relative to the total solid content of the radiation-sensitive resin composition.

[0124] (Other resins) The radiation-sensitive resin composition of this embodiment may also contain, as another resin, a resin with a higher mass content of fluorine atoms than the base resin (hereinafter also referred to as "high-fluorine content resin"). When the radiation-sensitive resin composition contains a high-fluorine content resin, it can be unevenly distributed on the surface of the resist film relative to the base resin, and as a result, the water repellency of the surface of the resist film during immersion exposure can be improved.

[0125] As a high-fluorine-content resin, it is preferable to have a structural unit represented by the following formula (7) (hereinafter also referred to as "structural unit (V)"), and may optionally have structural unit (I) or structural unit (II) of the base resin.

[0126] [ka]

[0127] In equation (7) above, R15 This is a hydrogen atom, a methyl group, or a trifluoromethyl group. L R is a single bond, an oxygen atom, a sulfur atom, -COO-, -SO2ONH-, -CONH-, or -OCONH-. 16 This is a monovalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated alicyclic hydrocarbon group having 3 to 20 carbon atoms.

[0128] The above R 15 From the viewpoint of copolymerization of monomers that provide structural unit (V), hydrogen atoms and methyl groups are preferred, and methyl groups are more preferred.

[0129] The above G L From the viewpoint of copolymerization of monomers that provide structural unit (V), single bonds and -COO- are preferred, and -COO- is more preferred.

[0130] The above R 16 Examples of monovalent fluorinated linear hydrocarbon groups having 1 to 20 carbon atoms, represented by , include those in which some or all of the hydrogen atoms in a linear or branched alkyl group having 1 to 20 carbon atoms are substituted with fluorine atoms.

[0131] The above R 16 Examples of monovalent fluorinated alicyclic hydrocarbon groups having 3 to 20 carbon atoms, represented by , include those in which some or all of the hydrogen atoms in a monocyclic or polycyclic hydrocarbon group having 3 to 20 carbon atoms are substituted with fluorine atoms.

[0132] The above R 16 Preferably, the group is a fluorinated chain hydrocarbon group, more preferably a fluorinated alkyl group, and even more preferably a 2,2,2-trifluoroethyl group, a 1,1,1,3,3,3-hexafluoropropyl group, and a 5,5,5-trifluoro-1,1-diethylpentyl group.

[0133] When a high-fluorine-content resin has structural units (V), the content of structural units (V) is preferably 30 mol% or more, more preferably 40 mol% or more, even more preferably 45 mol% or more, and particularly preferably 50 mol% or more, relative to the total structural units constituting the high-fluorine-content resin. Furthermore, it is preferably 95 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less. By setting the content of structural units (V) within the above range, the mass content of fluorine atoms in the high-fluorine-content resin can be more appropriately adjusted, further promoting the uneven distribution to the surface layer of the resist film, and as a result, the water repellency of the resist film during immersion exposure can be further improved.

[0134] High-fluorine content resins may have fluorine atom-containing structural units (hereinafter also referred to as structural unit (VI)) represented by the following formula (f-2), either together with or in place of structural unit (V). The presence of structural unit (VI) in high-fluorine content resins improves solubility in alkaline developers and suppresses the occurrence of development defects.

[0135] [ka]

[0136] Structural units (VI) can be broadly classified into two types: (x) those having an alkali-soluble group, and (y) those having a group that dissociates upon the action of alkali, increasing its solubility in an alkaline developer (hereinafter also simply referred to as an "alkali-dissociable group"). In both (x) and (y), in the above formula (f-2), R C R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. D This is a single bond, a (s+1) valent hydrocarbon group with 1 to 20 carbon atoms, and the R of this hydrocarbon group E At the terminal end of the side are an oxygen atom, a sulfur atom, and -NR dd -, a structure to which a carbonyl group, -COO-, or -CONH- is bonded, or a structure in which some of the hydrogen atoms of this hydrocarbon group are replaced by an organic group having a heteroatom. ddis a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. s is an integer from 1 to 3.

[0137] If structural unit (VI) has (x) an alkali-soluble group, R F is a hydrogen atom, A 1 * is an oxygen atom, -COO-* or -SO2O-*. F This shows the site of binding. 1 A is a single bond, a hydrocarbon group having 1 to 20 carbon atoms, or a divalent fluorinated hydrocarbon group. 1 If is an oxygen atom, then W 1 is A 1 It is a fluorinated hydrocarbon group having a fluorine atom or a fluoroalkyl group at the carbon atom to which it is bonded. E is a single bond or a divalent organic group with 1 to 20 carbon atoms. If s is 2 or 3, there are multiple R E , W 1 , A 1 and R F These may be the same or different. Having (x) an alkali-soluble group in structural unit (VI) increases its affinity for alkaline developer and suppresses development defects. A structural unit (VI) having (x) an alkali-soluble group is A 1 is an oxygen atom and W 1 It is particularly preferable that the group is a 1,1,1,3,3,3-hexafluoro-2,2-methanediyl group.

[0138] If structural unit (VI) has an alkali-dissociable group (y), R F A is a monovalent organic group having 1 to 30 carbon atoms. 1 is an oxygen atom, -NR aa -, -COO-* or -SO2O-* aa * is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. F This shows the site of binding. 1 R is a single bond or a divalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. E A is a single bond or a divalent organic group having 1 to 20 carbon atoms. 1 If is -COO-* or -SO2O-*, then W 1or R F is A 1 It has a fluorine atom on the carbon atom bonded to it or on an adjacent carbon atom. 1 If is an oxygen atom, then W 1 , R E It is a single bond, R D R is a hydrocarbon group with 1 to 20 carbon atoms. E It is a structure in which a carbonyl group is bonded to the terminal end, R F is an organic group containing a fluorine atom. When s is 2 or 3, multiple R E , W 1 , A 1 and R F These may be the same or different. The presence of (y) an alkali-dissociable group in structural unit (VI) causes the resist film surface to change from hydrophobic to hydrophilic during the alkali development process. As a result, the affinity for the developer is significantly increased, and development defects can be suppressed more efficiently. Examples of structural unit (VI) having (y) an alkali-dissociable group include A 1 is -COO-*, and R F Or W 1 Alternatively, it is particularly preferable that both of these contain fluorine atoms.

[0139] R C From the viewpoint of copolymerizability of the monomer that gives structural unit (VI), hydrogen atoms and methyl groups are preferred, and methyl groups are more preferred.

[0140] R E When the group is a divalent organic group, a group having a lactone structure is preferred, a group having a polycyclic lactone structure is more preferred, and a group having a norbornane lactone structure is even more preferred.

[0141] When a high-fluorine-content resin has structural units (VI), the content of structural units (VI) is preferably 50 mol% or more, more preferably 60 mol% or more, and even more preferably 70 mol% or more, relative to the total structural units constituting the high-fluorine-content resin. Furthermore, it is preferably 95 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less. By setting the content of structural units (VI) within the above range, the water repellency of the resist film during immersion exposure can be further improved.

[0142] [Other structural units] High-fluorine resins may also contain structural units having an alicyclic structure represented by the following formula (8), in addition to the structural units listed above. [ka] (In the above formula (8), R 1α R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 2α (It is a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms.)

[0143] In the above equation (8), R 2α Examples of monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, represented by , include those in which some or all of the hydrogen atoms in a monocyclic or polycyclic hydrocarbon group having 3 to 20 carbon atoms are substituted with fluorine atoms.

[0144] When a high-fluorine-content resin contains structural units having the above-mentioned alicyclic structure, the content of these structural units is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 30 mol% or more, relative to the total structural units constituting the high-fluorine-content resin. Furthermore, it is preferably 70 mol% or less, more preferably 60 mol% or less, and even more preferably 50 mol% or less.

[0145] The lower limit of Mw for the high-fluorine-content resin is preferably 1,000, more preferably 2,000, even more preferably 3,000, and particularly preferably 5,000. The upper limit of Mw is preferably 50,000, more preferably 30,000, even more preferably 20,000, and particularly preferably 15,000.

[0146] The lower limit of the Mw / Mn ratio for high-fluorine-content resins is usually 1, with 1.1 being more preferred. The upper limit of the above Mw / Mn ratio is usually 5, with 3 being preferred, 2 being more preferred, and 1.9 being even more preferred.

[0147] The content of the high-fluorine resin is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, even more preferably 1 part by mass or more, and particularly preferably 1.5 parts by mass or more, per 100 parts by mass of the base resin. Furthermore, it is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, even more preferably 10 parts by mass or less, and particularly preferably 8 parts by mass or less.

[0148] By setting the content of the high-fluorine-content resin within the above range, the high-fluorine-content resin can be more effectively distributed to the surface layer of the resist film, and as a result, the water repellency of the surface of the resist film during immersion exposure can be further enhanced. The radiation-sensitive resin composition may contain one or more high-fluorine-content resins.

[0149] (Method for synthesizing high-fluorine content resins) High-fluorine-content resins can be synthesized by the same method as the base resin synthesis method described above.

[0150] (solvent) The radiation-sensitive resin composition according to this embodiment contains a solvent. The solvent is not particularly limited as long as it is capable of dissolving or dispersing at least one compound represented by the above formula (1), one or more compounds represented by the above formula (2) or (3), and a resin containing a structural unit having an acid-dissociable group.

[0151] Examples of the solvent include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents, and the like.

[0152] Examples of the alcohol solvents include monohydric alcohol 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, 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, tripropylene glycol; polyhydric alcohol partial ether solvents obtained by etherifying a part of the hydroxy groups of the above polyhydric alcohol solvents, and the like.

[0153] Examples of the ether solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, dibutyl ether; cyclic ether solvents such as tetrahydrofuran, tetrahydropyran; aromatic ring-containing ether solvents such as diphenyl ether, anisole (methyl phenyl ether); polyhydric alcohol ether solvents obtained by etherifying the hydroxy groups of the above polyhydric alcohol solvents, and the like.

[0154] Examples of the ketone solvents include chain ketone solvents such as acetone, butanone, methyl-iso-butyl ketone; cyclic ketone solvents such as cyclopentanone, cyclohexanone, methylcyclohexanone; 2,4-pentanedione, acetonylacetone, acetophenone, and the like can be mentioned.

[0155] Examples of amide solvents include cyclic amide solvents such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone; chain amide solvents such as N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, and N-methylpropionamide, etc. can be mentioned.

[0156] Examples of ester solvents include, for example, monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate; 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; polyhydric carboxylic acid diester solvents such as propylene glycol diacetate, methoxytriglycol acetate, diethyl oxalate, ethyl acetoacetate, ethyl lactate, and diethyl phthalate can be mentioned.

[0157] Examples of hydrocarbon solvents include, for example, aliphatic hydrocarbon solvents such as n-hexane, cyclohexane, and methylcyclohexane; aromatic hydrocarbon solvents such as benzene, toluene, di-iso-propylbenzene, and n-amylnaphthalene, etc. can be mentioned.

[0158] Among these, ester solvents and ketone solvents are preferred, polyhydric alcohol partial ether acetate solvents, cyclic ketone solvents, and lactone solvents are more preferred, and propylene glycol monomethyl ether acetate, cyclohexanone, and γ-butyrolactone are even more preferred. The radiation-sensitive resin composition may contain one or more solvents.

[0159] (Other optional components) The radiation-sensitive resin composition of the present invention may contain other optional components in addition to the components described above. Examples of these other optional components include radiation-sensitive acid generators other than compound (1), compound (2), and compound (3), other acid diffusion control agents, crosslinking agents, localization accelerators, surfactants, alicyclic skeleton-containing compounds, sensitizers, and the like. These other optional components may be used individually or in combination of two or more types.

[0160] (Other radiation-sensitive acid generators) The radiation-sensitive resin composition of the present invention may further contain radiation-sensitive acid generators (acid generator (I) and acid generator (II)) other than the compounds (1), (2), and (3) described above. The radiation-sensitive acid generator may be contained in the form of a compound alone, incorporated as part of a polymer, or both, but the form of a compound alone is preferred. Examples of radioactive acid generators include onium salt compounds, sulfonimide compounds, halogen-containing compounds, and diazoketone compounds. Examples of onium salt compounds include sulfonium salts, tetrahydrothiophenium salts, iodonium salts, phosphonium salts, diazonium salts, and pyridinium salts. Of these, sulfonium salts and iodonium salts are preferred.

[0161] Examples of radioactive acid generators that act as acid generators (I) include sulfonium salts having a structure in which a halogen atom is located near the sulfonate anion. Among these, those having a cyclic structure in the anion are particularly preferred.

[0162] These radiation-sensitive acid generators may be used individually or in combination of two or more types. The total content of the acid generator (I), including compounds (1), (2), and (3), is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the base resin. Furthermore, per 100 parts by mass of the resin, it is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, even more preferably 30 parts by mass or less, and particularly preferably 20 parts by mass or less. This allows for excellent sensitivity, LWR performance, and CDU performance during resist pattern formation.

[0163] (Other acid diffusion control agents) The radiation-sensitive resin composition of the present invention may contain an acid diffusion control agent other than the acid generator (II) described above. The acid diffusion control agent controls the diffusion phenomenon of the acid generated from the acid generator (I) in the resist film upon exposure, and has the effect of suppressing undesirable chemical reactions in the unexposed areas. Furthermore, the storage stability of the resulting radiation-sensitive resin 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 resin composition with excellent process stability.

[0164] Other suitable acid diffusion control agents include nitrogen-containing compounds, such as the compound represented by formula (9) below (hereinafter also referred to as "nitrogen-containing compound (I)"), compounds having two nitrogen atoms in the same molecule (hereinafter also referred to as "nitrogen-containing compound (II)"), compounds having three nitrogen atoms (hereinafter also referred to as "nitrogen-containing compound (III)"), amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like.

[0165] [ka]

[0166] In the above equation (9), R 17 , R 18 and R 19Each 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.

[0167] Examples of nitrogen-containing compounds (I) include monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; trialkylamines such as triethylamine; and aromatic amines such as aniline. Examples of nitrogen-containing compounds (II) include ethylenediamine and N,N,N',N'-tetramethylethylenediamine. Examples of nitrogen-containing compounds (III) include polyamine compounds such as polyethyleneimine and polyallylamine; and polymers such as dimethylaminoethylacrylamide. 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. 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. Examples of nitrogen-containing heterocyclic compounds include pyridines such as pyridine and 2-methylpyridine; morpholines such as N-propylmorpholine and N-(undecylcarbonyloxyethyl)morpholine; and pyrazines and pyrazoles.

[0168] In addition, as the nitrogen-containing compound, a compound having an acid dissociable group can also be used. Examples of such nitrogen-containing organic compounds having an acid dissociable group include N-t-butoxycarbonylpiperidine, 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-amyloxycarbonyl-4-hydroxypiperidine, and the like.

[0169] These acid diffusion control agents may be used alone or in combination of two or more. The total content of the acid generator (II) including the compound (1), the compound (2), and the compound (3) and the acid diffusion control agent including the above nitrogen-containing compound is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more with respect to the total number of moles of the acid generator (I). Also, it is preferably 40 mol% or less, more preferably 30 mol% or less, and even more preferably 25 mol% or less with respect to the total number of moles of the acid generator (I). By setting the content of the acid diffusion control agent within the above range, the lithography performance of the radiation-sensitive resin composition can be further improved.

[0170] (Crosslinking agent) The crosslinking agent is a compound having two or more functional groups, and in the baking step after the batch exposure step, it causes a crosslinking reaction in the above resin component by an acid-catalyzed reaction, and increases the molecular weight of the above resin component, thereby reducing the solubility of the pattern-exposed portion in the developer. Examples of the above functional groups include (meth)acryloyl group, hydroxymethyl group, alkoxymethyl group, epoxy group, vinyl ether group, and the like.

[0171] (Non-uniformity promoting agent) The segregation accelerator has the effect of more efficiently segregating the high-fluorine-content resin on the resist film surface. By including this segregation accelerator in the radiation-sensitive resin composition, the amount of high-fluorine-content resin added can be reduced compared to conventional methods. Therefore, while maintaining the lithography performance of the radiation-sensitive resin composition, it becomes possible to further suppress the elution of components from the resist film into the immersion medium and to perform immersion exposure at a higher speed by high-speed scanning, thereby improving the hydrophobicity of the resist film surface, which suppresses immersion-derived defects such as watermark defects. Examples of compounds that can be used as such segregation accelerators include low-molecular-weight compounds with a relative permittivity of 30 to 200 and a boiling point of 100°C or higher at 1 atmosphere. Specifically, such compounds include lactone compounds, carbonate compounds, nitrile compounds, and polyhydric alcohols.

[0172] Examples of the above-mentioned lactone compounds include γ-butyrolactone, valerolactone, mevalonic lactone, and norbornane lactone.

[0173] Examples of the carbonate compounds mentioned above include propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate, and the like.

[0174] Examples of the nitrile compounds mentioned above include succinonitrile.

[0175] Examples of the polyhydric alcohols mentioned above include glycerin.

[0176] The amount of the segregation accelerator is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, and even more preferably 25 parts by mass or more, based on 100 parts by mass of the total amount of resin in the radiation-sensitive resin composition. Furthermore, it is preferably 300 parts by mass or less, more preferably 200 parts by mass or less, even more preferably 100 parts by mass or less, and particularly preferably 80 parts by mass or less. The radiation-sensitive resin composition may contain one or more types of segregation accelerators.

[0177] (Surfactants) Surfactants improve the properties of coating, striation, and development. Examples of surfactants include nonionic surfactants such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, and polyethylene glycol distearate; commercially available examples include KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, and No. 75. Examples include 95 (manufactured by Kyoeisha Chemical), F-Top EF301, EF303, EF352 (manufactured by Tochem Products), Megafac F171, F173 (manufactured by DIC), Florard FC430, FC431 (manufactured by Sumitomo 3M), Asahiguard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (manufactured by Asahi Glass Industries), etc. The surfactant content in the above radiation-sensitive resin composition is usually 2 parts by mass or less per 100 parts by mass of resin.

[0178] (Alicyclic skeleton-containing compounds) Compounds containing alicyclic skeletons have the effect of improving dry etching resistance, pattern shape, and adhesion to the substrate.

[0179] Examples of alicyclic skeleton-containing compounds include, Adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and t-butyl 1-adamantanecarboxylic acid; Deoxycholic acid esters such as t-butyl deoxycholate, t-butoxycarbonylmethyl deoxycholate, and 2-ethoxyethyl deoxycholate; Lithocholic acid esters such as t-butyl lithocholate, t-butoxycarbonylmethyl lithocholate, and 2-ethoxyethyl lithocholate; Examples include 3-[2-hydroxy-2,2-bis(trifluoromethyl)ethyl]tetracyclo[4.4.0.1(2,5).1(7,10)]dodecane and 2-hydroxy-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo[4.2.1.0(3,7)]nonane. The content of the alicyclic skeleton-containing compound in the above radiation-sensitive resin composition is usually 5 parts by mass or less per 100 parts by mass of resin.

[0180] (Sensitizer) The sensitizer increases the amount of acid produced from the radiation-sensitive acid generator, etc., and thus improves the "apparent sensitivity" of the above-mentioned radiation-sensitive resin composition.

[0181] Examples of sensitizers include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, and phenothiazines. These sensitizers may be used alone or in combination of two or more. The content of the sensitizer in the above-mentioned radiation-sensitive resin composition is usually 2 parts by mass or less per 100 parts by mass of resin.

[0182] <Method for preparing a radiation-sensitive resin composition> The above radiation-sensitive resin composition can be prepared, for example, by mixing compound (1), a resin containing a structural unit having an acid-dissociable group, one or more compounds represented by formula (2) or (3), a high-fluorine-content resin as needed, and a solvent in a predetermined proportion. After mixing, the above radiation-sensitive resin composition is preferably filtered using, for example, a filter with a pore size of about 0.05 μm. The solid content concentration of the above radiation-sensitive resin composition is usually 0.1% to 50% by mass, preferably 0.5% to 30% by mass, and more preferably 1% to 20% by mass.

[0183] <Pattern Formation Method> A method for forming a resist pattern according to one embodiment of the present invention is: The above radiation-sensitive resin composition is applied directly or indirectly to a substrate to form a resist film (1) (hereinafter also referred to as the "resist film formation step"), The above resist film is exposed in step (2) (hereinafter also referred to as the "exposure step"), The process includes (3) developing the exposed resist film (hereinafter also referred to as the "development step").

[0184] According to the above resist pattern formation method, a high-quality resist pattern can be formed because the above-mentioned radiation-sensitive resin composition, which has excellent sensitivity, CDU performance, and pattern rectangularity in the exposure process, is used. The following describes each step.

[0185] [Resist film formation process] In this step (step (1) above), a resist film is formed using the radiation-sensitive resin 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 140°C, with 80°C to 120°C being preferred. The PB time is usually 5 seconds to 600 seconds, with 10 seconds to 300 seconds being preferred. The thickness of the formed resist film is preferably 10 nm to 1,000 nm, and more preferably 10 nm to 500 nm.

[0186] When performing immersion exposure, regardless of the presence or absence of water-repellent polymer additives such as the high-fluorine-content resin in the above-mentioned radiation-sensitive resin composition, a protective immersion film insoluble in the immersion liquid may be provided on the formed resist film to avoid direct contact between the immersion liquid and the resist film. As the protective immersion film, either a solvent-peelable protective film that is peeled off with a solvent before the development process (see, for example, Japanese Patent Application Publication No. 2006-227632) or a developer-peelable protective film that is peeled off simultaneously with development in the development process (see, for example, Japanese Patent Application Publication Nos. WO2005-069076 and WO2006-035790) may be used. However, from the viewpoint of throughput, it is preferable to use a developer-peelable protective immersion film.

[0187] Furthermore, when the subsequent exposure process is carried out with radiation of a wavelength of 50 nm or less, it is preferable to use a resin having the above structural units (I) and (IV) as the base resin in the above composition.

[0188] [Synthesis process] In this step (step (2) above), the resist film formed in the resist film formation step (1) above is exposed by irradiating it with radiation through a photomask (and, in some cases, through an immersion medium such as water). The radiation used for exposure can be electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, EUV (extreme ultraviolet light), X-rays, and gamma rays, depending on the line width of the desired pattern; or charged particle beams such as electron beams and alpha rays. Among these, far ultraviolet light, electron beams, and EUV are preferred, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), electron beams, and EUV are more preferred, and electron beams and EUV with wavelengths of 50 nm or less, which are positioned as next-generation exposure technologies, are even more preferred.

[0189] When exposure is performed by immersion lithography, the immersion liquid used can be, for example, water or a fluorinated inert liquid. The immersion liquid is preferably transparent to the exposure wavelength and has the smallest possible temperature coefficient of refractive index to minimize distortion of the optical image projected onto the film. In particular, when the exposure light source is ArF excimer laser light (wavelength 193 nm), in addition to the above considerations, water is preferred due to its availability and ease of handling. When water is used, a small amount of an additive that reduces the surface tension of the water and increases its surfactant properties may be added. This additive is preferably one that does not dissolve the resist film on the wafer and has negligible effect on the optical coating on the underside of the lens. Distilled water is preferred as the water used.

[0190] After the exposure described above, it is preferable to perform a post-exposure bake (PEB) to promote the dissociation of acid-dissociable groups in the resin, etc., by the acid generated from the radiation-sensitive acid generator during exposure in the exposed portion of the resist film. This PEB creates a difference in solubility in the developer between the exposed and unexposed portions. The PEB temperature is usually 50°C to 180°C, with 80°C to 130°C being preferred. The PEB time is usually 5 seconds to 600 seconds, with 10 seconds to 300 seconds being preferred.

[0191] [Development process] In this step (step (3) above), the resist film exposed in the exposure step (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.

[0192] 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, or 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.

[0193] 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 resin 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.

[0194] As mentioned above, either an alkaline developer or an organic solvent developer may be used as the developing solution.

[0195] 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 piling 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 onto a substrate rotating at a constant speed while scanning the developer solution dispensing nozzle at a constant speed (dynamic dispensing method). [Examples]

[0196] 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.

[0197] [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 Mw and Mn values.

[0198] [ 13 C-NMR analysis] resin 13 ¹¹C-NMR analysis was performed using a nuclear magnetic resonance spectrometer (JNM-Delta400, manufactured by JEOL Ltd.).

[0199] <Synthesis of resins and high-fluorine content resins> The monomers used in the synthesis of each resin and high-fluorine-content resin 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%.

[0200] [ka]

[0201] [Synthesis Example 1] (Synthesis of resin (A-1)) Monomers (M-1), (M-2), and (M-6) were dissolved in 200 parts by mass of 2-butanone in a molar ratio of 40 / 15 / 45 (mol%). AIBN (azobisisobutyronitrile) (5 mol% of the total monomers used, based on 100 mol%) was added as an initiator to prepare the monomer solution. 100 parts by mass of 2-butanone was placed in the reaction vessel, and after purging with nitrogen for 30 minutes, the reaction vessel was heated to 80°C. The monomer solution was then 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.

[0202] After the polymerization reaction was complete, 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 dried at 50°C for 24 hours to obtain a white powdery resin (A-1) (yield: 85%). The Mw of resin (A-1) was 6,500, and the Mw / Mn ratio was 1.55. Furthermore, 13C-NMR analysis revealed that the content of each structural unit derived from (M-1), (M-2), and (M-6) was 39.8 mol%, 13.4 mol%, and 46.8 mol%, respectively. [Synthesis Examples 2-11] (Synthesis of resins (A-2) to (A-11)) Resins (A-2) to (A-11) were synthesized in the same manner as in Synthesis Example 1, except that the monomers used were of the types and proportions shown in Table 1 below. The content (mol%), yield (%), and physical properties (Mw and Mw / Mn) of each structural unit of the obtained resins are also shown in Table 1 below. In Table 1 below, "-" indicates that the corresponding monomer was not used (the same applies to subsequent tables).

[0203] [Table 1]

[0204] [Synthesis Example 12] (Synthesis of resin (A-12)) Monomer (M-1) and monomer (M-18) were dissolved in 1-methoxy-2-propanol (200 parts by mass) in a molar ratio of 45 / 55 (mol%), and AIBN (5 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 reaction vessel was heated 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.

[0205] After the polymerization reaction was complete, the polymerization solution was cooled to below 30°C by water cooling. The cooled polymerization solution was added to hexane (2,000 parts by mass), and the precipitated white powder was filtered off. The filtered white powder was washed twice with hexane, 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 obtained solid was dissolved in acetone (100 parts by mass) and added dropwise to water (500 parts by mass) to solidify the resin. The obtained solid was filtered off and dried at 50°C for 13 hours to obtain a white powdery resin (A-12) (yield: 75%). The Mw of resin (A-12) was 6,400, and the Mw / Mn ratio was 1.55. Furthermore, 13C-NMR analysis revealed that the content of each structural unit derived from (M-1) and (M-18) was 41.3 mol% and 58.7 mol%, respectively.

[0206] [Synthesis Examples 13-15] (Synthesis of resin (A-13) to resin (A-15)) Resins (A-13) to (A-15) were synthesized in the same manner as in Synthesis Example 12, except that the monomers used were of the types and proportions shown in Table 2 below. The content (mol%), yield (%), and physical properties (Mw and Mw / Mn) of each structural unit of the obtained resins are also shown in Table 2 below.

[0207] [Table 2]

[0208] [Synthesis Example 16] (Synthesis of high-fluorine content resin (E-1)) Monomer (M-4) and monomer (M-20) were dissolved in 200 parts by mass of 2-butanone to a molar ratio of 20 / 80 (mol%), and AIBN (7 mol%) was added as an initiator to prepare a monomer solution. 100 parts by mass of 2-butanone 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.

[0209] After the polymerization reaction was complete, the polymerization solution was cooled to below 30°C by water cooling. The solvent was replaced with acetonitrile (400 parts by mass), then hexane (100 parts by mass) was added and stirred, and the acetonitrile layer was recovered. This process was repeated three times. By replacing the solvent with propylene glycol monomethyl ether acetate, a solution of high-fluorine content resin (E-1) was obtained (yield: 61%). The Mw of high-fluorine content resin (E-1) was 6,000, and the Mw / Mn ratio was 1.62. Furthermore, 13C-NMR analysis revealed that the content of each structural unit derived from (M-4) and (M-20) was 19.9 mol% and 80.1 mol%, respectively.

[0210] [Synthesis Examples 17-20] (Synthesis of high-fluorine content resins (E-2) to high-fluorine content resins (E-5)) High-fluorine-content resins (E-2) to (E-5) were synthesized in the same manner as in Synthesis Example 16, except that monomers of the types and proportions shown in Table 3 below were used. The content (mol%), yield (%), and physical properties (Mw and Mw / Mn) of each structural unit of the obtained high-fluorine-content resins are shown in accordance with Table 3 below.

[0211] [Table 3]

[0212] <Synthesis of radiation-sensitive acid generator B> [Synthesis Example 21] (Synthesis of compound (B-1)) Compound (B-1) was synthesized according to the following synthesis scheme.

[0213] [ka]

[0214] 45 mmol of alcohol, 45 mmol of acid chloride, 60 mmol of pyridine, and 100 g of tetrahydrofuran were added to a reaction vessel and stirred at room temperature for 4 hours. Afterward, aqueous ammonium chloride solution was added to stop the reaction, and then ethyl acetate was added for extraction, separating the organic layer. The obtained organic layer was washed with water. After drying over sodium sulfate, the solvent was removed by distillation, and the ester was obtained in good yield by column chromatography.

[0215] 50 mmol of the above ester compound was mixed with 80 mmol of sodium dithionite, 120 mmol of sodium bicarbonate, 50 mmol of benzyltrimethylammonium chloride, and 300 g of a mixture of acetonitrile and water (1:1 by mass ratio), and the mixture was stirred at 70°C for 5 hours. After that, an aqueous solution of sodium thiosulfate was added to stop the reaction, and the organic layer was recovered. After extraction with acetonitrile and removal of the solvent by distillation, a mixture of acetonitrile and water (3:1 by mass ratio) was added to make a 0.5 M solution. 120.0 mmol of hydrogen peroxide and 4.00 mmol of sodium tungstate were added, and the mixture was heated and stirred at 50°C for 12 hours. The sodium sulfonate salt compound was obtained by extraction with acetonitrile and removal of the solvent by distillation.

[0216] 20 mmol of the above sulfonate was mixed with 20 mmol of TPSC, 100 g of methylene chloride, and 50 g of water, and the mixture was reacted at room temperature for 12 hours. After dilution with water, methylene chloride was added for extraction, and the organic layer was separated. The obtained organic layer was washed with water. After drying over sodium sulfate, the solvent was removed by distillation, and the compound represented by formula (B-1) was obtained in good yield by column chromatography.

[0217] [Synthesis Examples 22-39] (Synthesis of compounds (B-2) to (B-19) and compound (C-14)) Except for appropriately changing the raw materials and precursors, a radiation-sensitive acid generator represented by the following formulas (B-2) to (B-19) and an acid diffusion control agent represented by the following formula (C-14) were synthesized in the same manner as in Synthesis Example 21.

[0218] [ka]

[0219] [ka]

[0220] [ka]

[0221] [Radiation-sensitive acid generators other than compounds (B-1) to (B-19)] b-1 to b-7: Compounds represented by the following formulas (b-1) to (b-7) (hereinafter, compounds represented by formulas (b-1) to (b-7) may be referred to as "compound (b-1)" to "compound (b-7)," respectively).

[0222] [ka]

[0223] [Acid diffusion control agents other than compound (C-14)] C-1 to C-13: Compounds represented by the following formulas (C-1) to (C-13).

[0224] [Chemical formula]

[0225] [Solvent [D]] D-1: Propylene glycol monomethyl ether acetate D-2: Propylene glycol monomethyl ether D-3: γ-Butyrolactone D-4: Ethyl lactate

[0226] [Preparation of positive radiation-sensitive resin composition for ArF exposure] [Example 1] [100 parts by mass of (A-1) as the resin, 12.0 parts by mass of (B-1) as the radiation-sensitive acid generator, 3.0 parts by mass of (C-1) as the acid diffusion controller, 3.0 parts by mass (solid content) of (E-1) as the high fluorine content resin, and 3,230 parts by mass of the mixed solvent of (D-1) / (D-2) / (D-3) as the solvent [D] were mixed and filtered through a membrane filter with a pore size of 0.2 μm to prepare a radiation-sensitive resin composition (J-1).]

[0227] [Examples 2 to 47 and Comparative Examples 1 to 20] [Except for using the components of the types and contents shown in Table 4 below, in the same manner as in Example 1, radiation-sensitive resin compositions (J-2) to (J-47) and (CJ-1) to (CJ-20) were prepared.]

[0228] [Table 4]

[0229] [Formation of resist pattern using positive radiation-sensitive resin composition for ArF exposure] On a 12-inch silicon wafer, a base layer anti-reflective coating composition (Brewer Science's "ARC66") was applied using a spin coater (CLEAN TRACK ACT12, manufactured by Tokyo Electron Limited), and then heated at 205°C for 60 seconds to form a base layer anti-reflective coating with an average thickness of 100 nm. On this base layer anti-reflective coating, the ArF exposure positive-type radiation-sensitive resin composition prepared above was applied using the same spin coater, and pre-bake (PB) was performed at 100°C for 60 seconds. Subsequently, a resist film with an average thickness of 90 nm was formed by cooling at 23°C for 30 seconds. Next, this resist film was exposed using an ArF excimer laser immersion lithography system (TWINSCAN XT-1900i, manufactured by ASML) under optical conditions of NA=1.35 and Dipole (σ=0.9 / 0.7) through a 40 nm line-and-space mask pattern. After exposure, post-exposure baking (PEB) was performed at 100°C for 60 seconds. Subsequently, the resist film was alkaline developed using a 2.38% by mass aqueous TMAH solution as the alkaline developer. After development, it was washed with water and then dried to form a positive-type resist pattern (40 nm line and space pattern).

[0230] <Rating> The sensitivity, LWR performance, and pattern rectangularity of resist patterns formed using the above-described positive-type radiation-sensitive resin composition for ArF exposure were evaluated according to the method described below. The results are shown in Table 5 below. A scanning electron microscope (Hitachi High-Technologies Corporation's "CG-5000") was used to measure the length of the resist patterns.

[0231] [sensitivity] In forming a resist pattern using the above-mentioned positive-type radiation-sensitive resin composition for ArF exposure, the exposure amount used to form a 40 nm line-and-space pattern is defined as the optimal exposure amount, and this optimal exposure amount is set to the sensitivity (mJ / cm²). 2 The sensitivity was set to 25 mJ / cm². 2 The following cases are considered "good" and 25 mJ / cm². 2 If it exceeded this value, it was rated as "poor."

[0232] [LWR performance] A 40nm line-and-space resist pattern was formed by irradiating with the optimal exposure dose determined in the sensitivity evaluation described above. The formed resist pattern was observed from the top using the scanning electron microscope described above. The line width variation was measured at a total of 500 points, and the 3-sigma value was determined from the distribution of these measurements. This 3-sigma value was defined as LWR (nm). A smaller LWR value indicates less line roughness and better performance. LWR performance was evaluated as "good" if it was 3.0nm or less, and "poor" if it was greater than 3.0nm.

[0233] [Pattern Rectangle] The 40nm line-and-space resist patterns formed by irradiating with the optimal exposure dose 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 was 1 or more and 1.05 or less, it was evaluated as "A" (excellent); 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).

[0234] [Table 5]

[0235] As is clear from the results in Table 5, the radiation-sensitive resin composition of the example showed good sensitivity, LWR performance, and pattern rectangularity when used in ArF exposure. In contrast, the comparative example exhibited inferior characteristics compared to the example. Therefore, when the radiation-sensitive resin composition of the example is used in ArF exposure, a resist pattern with high sensitivity and good LWR performance can be formed.

[0236] [Preparation of radiation-sensitive resin compositions for extreme ultraviolet (EUV) exposure] [Example 48] 100 parts by mass of (A-12) as a resin, 15.0 parts by mass of (B-1) as a radiation-sensitive acid generator, 4.0 parts by mass of (C-1) as an acid diffusion controller, 3.0 parts by mass (solid content) of (E-1) as a high-fluorine content resin, and 6,110 parts by mass of a mixed solvent of (D-1) / (D-4) as a solvent were mixed and filtered through a membrane filter with a pore size of 0.2 μm to prepare a radiation-sensitive resin composition (J-48).

[0237] [Examples 49 to 57 and Comparative Examples 21 to 24] Radiation-sensitive resin compositions (J-49) to (J-57) and (CJ-21) to (CJ-24) were prepared in the same manner as in Example 48, except that the components of the types and contents shown in Table 7 below were used.

[0238]

Table 6

[0239] <Formation of a resist pattern using a radiation-sensitive resin composition for EUV exposure> On a 12-inch silicon wafer, a base layer anti-reflective coating composition (Brewer Science's "ARC66") was applied using a spin coater (CLEAN TRACK ACT12, manufactured by Tokyo Electron Limited), and then heated at 205°C for 60 seconds to form a base layer anti-reflective coating with an average thickness of 105 nm. The radiation-sensitive resin composition for EUV exposure prepared above was applied to this base layer anti-reflective coating using the same spin coater, and PB was performed at 130°C for 60 seconds. Subsequently, a resist film with an average thickness of 55 nm was formed by cooling at 23°C for 30 seconds. Next, this resist film was exposed using an EUV exposure apparatus (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% by mass aqueous TMAH solution as the alkaline developer. After development, it was washed with water and then dried to form a positive-type resist pattern (32 nm line and space pattern).

[0240] <Rating> The sensitivity and LWR performance of resist patterns formed using the above-described radiation-sensitive resin composition for EUV exposure were evaluated according to the method described below. The results are shown in Table 8. A scanning electron microscope ("CG-5000" manufactured by Hitachi High-Technologies Corporation) was used to measure the length of the resist patterns.

[0241] [sensitivity] In forming a resist pattern using the above-mentioned radiation-sensitive resin composition for EUV exposure, the exposure amount for forming a 32nm line-and-space pattern is defined as the optimal exposure amount, and this optimal exposure amount is set to the sensitivity (mJ / cm²). 2 The sensitivity was set to 30 mJ / cm². 2 The following cases are considered "good" and 30 mJ / cm². 2 If it exceeded this value, it was rated as "poor."

[0242] [LWR performance] The mask size was adjusted to form a 32nm line-and-space 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 line width variation was measured at a total of 500 points, and the 3-sigma value was determined from the distribution of these measurements. This 3-sigma value was defined as LWR (nm). A smaller LWR value indicates less line jaggedness and better performance. LWR performance was evaluated as "good" if it was 3.5nm or less, and "poor" if it was greater than 3.5nm.

[0243] [Pattern Rectangle] The 40nm line-and-space resist patterns formed by irradiating with the optimal exposure dose 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 was 1 or more and 1.05 or less, it was evaluated as "A" (excellent); 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).

[0244] [Table 7]

[0245] As is clear from the results in Table 7, the radiation-sensitive resin compositions of the examples showed good sensitivity, LWR performance, and pattern rectangularity when used in EUV exposure. In contrast, the comparative examples exhibited inferior characteristics compared to the examples.

[0246] [Preparation of negative-type radiation-sensitive resin composition for ArF exposure, formation and evaluation of resist patterns using this composition] [Example 58] A radiation-sensitive resin composition (J-58) was prepared by mixing [A] 100 parts by mass of (A-1) as a resin, [B] 12.0 parts by mass of (B-1) as a radiation-sensitive acid generator, [C] 4.0 parts by mass of (C-1) as an acid diffusion control agent, [E] 5.0 parts by mass (solids) of (E-5) as a high-fluorine-content resin, and [D] 3,230 parts by mass of a mixed solvent of (D-1) / (D-2) / (D-3) as a solvent, and filtering the mixture through a membrane filter with a pore size of 0.2 μm.

[0247] On a 12-inch silicon wafer, a base layer anti-reflective coating composition (ARC66, manufactured by Brewer Science) was applied using a spin coater (CLEAN TRACK ACT12, manufactured by Tokyo Electron Limited), and then heated at 205°C for 60 seconds to form a base layer anti-reflective coating with an average thickness of 100 nm. On this base layer anti-reflective coating, the ArF exposure negative-type radiation-sensitive resin composition (J-58) prepared above was applied using the same spin coater, and pre-bake (PB) was performed at 100°C for 60 seconds. Subsequently, a resist film with an average thickness of 90 nm was formed by cooling at 23°C for 30 seconds. Next, this resist film was exposed using an ArF excimer laser immersion lithography system (TWINSCAN XT-1900i, manufactured by ASML) under optical conditions of NA=1.35 and Annular (σ=0.8 / 0.6) through a mask pattern with 40 nm holes and a 105 nm pitch. After exposure, post-exposure baking (PEB) was performed at 100°C for 60 seconds. Subsequently, the resist film was developed using n-butyl acetate as the organic solvent developer and dried to form a negative-type resist pattern (40 nm holes, 105 nm pitch).

[0248] <Rating> The CDU performance of resist patterns formed using the above-mentioned ArF exposure negative-type radiation-sensitive resin composition was evaluated according to the following method. A scanning electron microscope ("CG-5000" manufactured by Hitachi High-Technologies Corporation) was used to measure the length of the resist patterns.

[0249] [CDU performance] A resist pattern with 40 nm holes and a 105 nm pitch was measured at 1,800 arbitrary points from the top of the pattern using the scanning electron microscope described above. The dimensional variation (3σ) was determined and defined as the CDU performance (nm). A smaller CDU value indicates less variation in hole diameter over long periods and therefore better performance.

[0250] As a result of evaluating the resist patterns using the above-mentioned negative-type radiation-sensitive resin composition for ArF exposure, the radiation-sensitive resin composition of Example 58 showed good sensitivity and CDU performance even when a negative-type resist pattern was formed by ArF exposure.

[0251] [Preparation of negative-type radiation-sensitive resin composition for EUV exposure, formation and evaluation of resist patterns using this composition] [Example 59] A radiation-sensitive resin composition (J-59) was prepared by mixing [A] 100 parts by mass of (A-16) as a resin, [B] 21.0 parts by mass of (B-1) as a radiation-sensitive acid generator, [C] 5.0 parts by mass of (C-1) as an acid diffusion control agent, [E] 3.0 parts by mass (solids) of (E-5) as a high-fluorine-content resin, and [D] 6,110 parts by mass of a mixed solvent of (D-1) / (D-4) as a solvent, and filtering the mixture through a membrane filter with a pore size of 0.2 μm.

[0252] On a 12-inch silicon wafer, a base layer anti-reflective coating composition (Brewer Science's "ARC66") was applied using a spin coater (CLEAN TRACK ACT12, manufactured by Tokyo Electron Limited), and then heated at 205°C for 60 seconds to form a base layer anti-reflective coating with an average thickness of 105 nm. The radiation-sensitive resin composition for EUV exposure prepared above was applied to this base layer anti-reflective coating using the same spin coater, and PB was performed at 130°C for 60 seconds. Subsequently, a resist film with an average thickness of 55 nm was formed by cooling at 23°C for 30 seconds. Next, this resist film was exposed using an EUV exposure apparatus (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 developed using n-butyl acetate as the organic solvent developer and dried to form a negative-type resist pattern (40 nm holes, 105 nm pitch).

[0253] The resist patterns using the above-mentioned negative-type radiation-sensitive resin composition for EUV exposure were evaluated in the same manner as the resist patterns using the above-mentioned negative-type radiation-sensitive resin composition for ArF exposure. As a result, the radiation-sensitive resin composition of Example 59 showed good sensitivity and CDU performance even when a negative-type resist pattern was formed by EUV exposure. [Industrial applicability]

[0254] The radiation-sensitive resin composition and pattern formation method described above allow for the formation of resist patterns that exhibit good sensitivity to exposure light and have excellent LWR performance and pattern rectangularity. Therefore, these can be suitably used in the processing of semiconductor devices, which are expected to become even more miniaturized in the future.

Claims

1. Compounds represented by the following formula (1) (excluding compounds represented by formula (B)-2, and compounds having anions represented by formulas (b2-a5), (b2-a6), and (b2-a9)). 【Chemistry 1】 (In formula (1), R ｆ This is a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms. R １ and R ２ Each of these is independently a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, a fluorine atom, or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms. L １ It is -COO- or -OCO-. A １ These are single bonds, methylene groups, and linear alkylene groups having 2 to 40 carbon atoms. L ２ These are -O-, -COO-, -OCO-, -S-, -NR-, -NRCO-, or -CONR-. R is a hydrogen atom or an organic group having 1 to 10 carbon atoms. A ２ This is a methyl group or a linear alkyl group having 2 to 40 carbon atoms. n1 is an integer from 0 to 4. When n1 is 2 or more, a plurality of R ｆ and R １ are the same as or different from each other. n² is an integer from 0 to 6. If n² is 2 or greater, multiple R ２ They are either identical or different from one another. However, the sum of n1 and n2 is an integer greater than or equal to 1. n3 is an integer between 0 and 10. If n3 is 2 or greater, multiple [-L ２ -A １ ―] are either identical or different from each other. However, all A １ and A ２ The total number of carbon atoms is 6 or more. Z １ ＋ (This is a sulfonium cation or an iodonium cation.) 【Chemistry 2】

2. A in the above formula (1) １ and A ２ The compound according to claim 1, wherein the total number of carbon atoms is 13 or more.

3. The compound according to claim 1, wherein n1 in formula (1) above is an integer from 1 to 4.

4. The compound according to claim 1, wherein n1 in formula (1) above is an integer from 1 to 3, and n2 is an integer from 1 to 4.

5. R in equation (1) above ｆ The compound according to claim 1, wherein is a fluorine atom or a trifluoromethyl group.

6. The compound according to claim 1, wherein n3 in formula (1) above is 0 or 1.

7. L in formula (1) above ２ The compound according to claim 1, wherein is -O-, -COO-, or -OCO-.

8. In the above equation (1), n1 is an integer between 2 and 3, and R １ The compound according to claim 1, wherein is a fluorine atom.

9. A radiation-sensitive acid generator comprising the compound described in any one of claims 1 to 8.

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