Radiation-sensitive resin composition and pattern forming method

Abstract

Provided are: a radiation-sensitive resin composition with which it is possible to form a resist film that is capable of exhibiting satisfactory levels of sensitivity, LWR performance, CDU performance and pattern rectangularity; and a pattern formation method. A radiation-sensitive resin composition which contains: an acid dissociation group-containing onium salt compound having a specific structure which satisfies conditions (i) and (ii); a resin containing a structural unit having an acid dissociation group; a photodegradable base; and a solvent. Condition (i): the change in van der Waals volume of an anion structure of said onium salt compound before and after acid dissociation group cleavage occurs as represented by formula (i) is 32-67%, inclusive. (i): (W1-W2) / (W1)×100(%) (In formula (i), W1 represents the van der Waals volume of the anion structure of the onium compound, and W2 represents the van der Waals volume of the structure after the acid dissociation group of the anion structure is cleaved by an acid produced by emitting active rays or radioactive rays.) Condition (ii): the difference in the ClogP value of the anion structure of said onium salt compound before and after acid dissociation group cleavage occurs as represented by formula (ii) is no more than 3.00. (ii): (P1-P2) (In formula (ii), P1 represents the ClogP value of the anion structure of the onium compound, and P2 represents the ClogP value of the structure after the acid dissociation group of the anion structure is cleaved by an acid produced by emitting active rays or radioactive rays.)

Description

[Technical Field]

[0001] The present invention relates to a radiation-sensitive resin composition and a pattern forming method. [Background technology]

[0002] Photolithography techniques using resist compositions are used to form fine circuits in semiconductor elements. A typical procedure involves, for example, exposing a coating of the resist composition to radiation through a mask pattern to generate an acid, which is then catalyzed by a reaction that causes a difference in the solubility of the resin in an alkaline or organic developer between the exposed and unexposed areas, thereby forming a resist pattern on a substrate.

[0003] The photolithography technology mentioned above is promoting pattern miniaturization by using short-wavelength radiation such as ArF excimer lasers, and also by using liquid immersion lithography, in which exposure is performed with the space between the lens of the exposure device and the resist film filled with a liquid medium. Lithography using even shorter-wavelength radiation such as electron beams, X-rays, and EUV (extreme ultraviolet) is also being considered as a next-generation technology.

[0004] As efforts toward further technological advances continue, attempts are being made to improve the sensitivity, resolution, etc. of photoacid generators, which are a major component of resist compositions. For example, with the aim of obtaining resist compositions with excellent lithography properties, acid generators having an acid-dissociable group in their anionic structure are being investigated (Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5814072 Summary of the Invention [Problem to be solved by the invention]

[0006] Even as efforts toward these next-generation technologies are underway, resist performance that is equal to or better than conventional performance is required in terms of sensitivity, LWR (Line Width Roughness) performance, which indicates the variation in line width of the resist pattern, critical dimension uniformity (CDU) performance, which is an index of the uniformity of line width and hole diameter, and pattern rectangularity, which indicates the rectangularity of the cross-sectional shape of the resist pattern.

[0007] An object of the present invention is to provide a radiation-sensitive resin composition and a pattern forming method that are capable of forming a resist film that exhibits sufficient levels of sensitivity, LWR performance, CDU performance, and pattern rectangularity. [Means for solving the problem]

[0008] As a result of extensive research into solving the above problem, the present inventors have found that the above object can be achieved by employing the following configuration, and have thus completed the present invention.

[0009] That is, in one embodiment, the present invention provides: an onium salt compound represented by the following formula (1) and satisfying the following conditions (i) and (ii); a resin including a structural unit having an acid-dissociable group; a photodegradable base; Solvent and The present invention relates to a radiation-sensitive resin composition comprising:

[0010] [ka]

[0011] (In the above formula (1), R 1 is a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms. R 2 , R 3 and R 4 are each independently a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 10 carbon atoms, or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms. m is an integer of 0 to 7, and when m is 2 or more, a plurality of R 3 and R 4 are the same or different from each other. A 1 is a single bond or a divalent cyclic organic group having 3 to 30 ring members. A 2 is a divalent chain hydrocarbon group having 1 to 10 carbon atoms or a divalent cyclic organic group having 3 to 30 ring members. L is a divalent linking group selected from -O-, -CO-, -COO-, -OCO-, -O-CO-O-, -S-, -SO2-, -CONH-, and -NHCO-. n is an integer of 0 to 2, and when n is 2, a plurality of A 2 and L are the same or different. R 5 is an acid-dissociable group represented by the following formula (1-1) or (1-2). Z + is a monovalent radiation-sensitive onium cation.

[0012] [ka]

[0013] (In the above formula (1-1), R 1A R is a monovalent hydrocarbon group having 1 to 20 carbon atoms. 1B and R 1C are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a divalent cyclic organic group having 3 to 20 ring members formed by combining these groups together with the carbon atoms to which they are bonded. * represents R in the above formula (1). 5 indicates the bonding site with the oxygen atom adjacent to In the above formula (1-2), Y is -O- or -S-. 2A is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R 2B is a monovalent hydrocarbon group having 1 to 20 carbon atoms, or R 2A and R 2Brepresents a divalent cyclic organic group having 4 to 20 ring members formed by combining together with the atomic chain to which they are bonded. * represents R 5 indicates the bonding site with the oxygen atom adjacent to

[0014] Condition (i): The rate of change in van der Waals volume of the anion structure of the onium salt compound represented by formula (1) above before and after cleavage of the acid-dissociable group represented by formula (i) below is 32% or more and 67% or less. (W1-W2) / (W1)×100(%) ···(i) (In the above formula (i), W1 represents the van der Waals volume of the anion structure of the onium salt compound represented by the above formula (1), and W2 represents the van der Waals volume of the structure after the acid-dissociable group of the anion structure is cleaved by the acid generated by irradiation with actinic rays or radiation.)

[0015] Condition (ii): The difference in ClogP value between the anion structure of the onium salt compound represented by the above formula (1) and the structure represented by the following formula (ii) before and after cleavage of the acid-dissociable group is 3.00 or less. (P1-P2) (ii) (In the above formula (ii), P1 represents the ClogP value of the anion structure of the onium salt compound represented by the above formula (1), and P2 represents the ClogP value of the structure after the acid-dissociable group of the anion structure has been cleaved by an acid generated by irradiation with actinic rays or radiation.)

[0016] The radiation-sensitive resin composition contains an onium salt compound (hereinafter also referred to as "compound (1)") as a radiation-sensitive acid generator that is represented by the above formula (1) and satisfies the above conditions (i) and (ii). This allows the composition to exhibit excellent sensitivity, LWR performance, CDU performance, and pattern rectangularity during resist pattern formation. While not bound by any theory, the reason for this is presumed to be as follows: An onium salt compound having an acid-dissociable group in its anionic structure functions as a radiation-sensitive photoacid generator. In exposed areas, the acid-dissociable group is cleaved, improving solubility in alkaline developers and thereby improving sensitivity, LWR, and CDU performance. In unexposed areas, the acid-dissociable group remains unchanged, maintaining hydrophobicity and preventing unwanted elution, thereby improving pattern rectangularity. If the van der Waals volume change before and after cleavage of the acid-dissociable group is too large, the acid diffusion length of the deprotected product will vary significantly, potentially resulting in poor LWR and CDU performance. Conversely, if the volume change is too small, the effect of cleavage of the acid-labile group is difficult to achieve.Furthermore, if the change in polarity before and after cleavage of the acid-labile group is too large, the solubility in the developer may vary, which may result in deterioration of LWR and CDU performance. In addition, the radiation-sensitive resin composition contains a photodegradable base, which makes the difference in solubility between the exposed and unexposed areas of compound (1) more pronounced, making it possible to form a resist film with even more excellent LWR performance and pattern rectangularity.

[0017] In another embodiment, the present invention provides a resist film production method, comprising: exposing the resist film to light; developing the exposed resist film with a developer; The present invention relates to a pattern forming method comprising the steps of:

[0018] This pattern formation method uses the above-mentioned radiation-sensitive resin composition, which is capable of forming a resist film that is excellent in sensitivity, LWR performance, CDU performance, and pattern rectangularity, and therefore can efficiently form a high-quality resist pattern. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these embodiments.

[0020] <Radiation sensitive resin composition> The radiation-sensitive resin composition according to this embodiment (hereinafter also simply referred to as the "composition") contains compound (1), a resin containing a structural unit having an acid-dissociable group, a photodegradable base, and a solvent. The composition may contain other optional components as long as the effects of the present invention are not impaired. The radiation-sensitive resin composition contains compound (1) as a radiation-sensitive acid generator, and further contains a photodegradable base, thereby imparting high levels of sensitivity, LWR performance, CDU performance, and pattern rectangularity to a resist film of the radiation-sensitive resin composition.

[0021] (Compound (1)) Compound (1) is an onium salt compound represented by the above formula (1) and satisfying the following conditions (i) and (ii), and functions as a radiation-sensitive acid generator that generates an acid upon irradiation with radiation. The composition may contain one type of compound (1) or multiple types of compounds (1).

[0022] R 1 , R 2 , R 3 and R 4 Examples of the monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms represented by the formula (I) include a monovalent fluorinated chain hydrocarbon group having 1 to 10 carbon atoms and a monovalent fluorinated alicyclic hydrocarbon group having 3 to 10 carbon atoms.

[0023] Examples of the monovalent fluorinated chain hydrocarbon group having 1 to 10 carbon atoms include fluorinated alkyl groups such as a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a pentafluoroethyl group, a 2,2,3,3,3-pentafluoropropyl group, a 1,1,1,3,3,3-hexafluoropropyl group, a heptafluoro-n-propyl group, a heptafluoro-i-propyl group, a nonafluoro-n-butyl group, a nonafluoro-i-butyl group, a nonafluoro-t-butyl group, a 2,2,3,3,4,4,5,5-octafluoro-n-pentyl group, a tridecafluoro-n-hexyl group, and a 5,5,5-trifluoro-1,1-diethylpentyl group; fluorinated alkenyl groups such as a trifluoroethenyl group and a pentafluoropropenyl group; Examples include fluorinated alkynyl groups such as a fluoroethynyl group and a trifluoropropynyl group.

[0024] Examples of the monovalent fluorinated alicyclic hydrocarbon group having 3 to 10 carbon atoms include fluorinated cycloalkyl groups such as a fluorocyclopentyl group, a difluorocyclopentyl group, a nonafluorocyclopentyl group, a fluorocyclohexyl group, a difluorocyclohexyl group, an undecafluorocyclohexylmethyl group, a fluoronorbornyl group, a fluoroadamantyl group, a fluorobornyl group, a fluoroisobornyl group, and a fluorotricyclodecyl group; Examples include fluorinated cycloalkenyl groups such as a fluorocyclopentenyl group and a nonafluorocyclohexenyl group.

[0025] The above fluorinated hydrocarbon group is preferably the above monovalent fluorinated chain hydrocarbon group having 1 to 8 carbon atoms, more preferably a monovalent fluorinated chain hydrocarbon group having 1 to 4 carbon atoms.

[0026] R 2 , R 3 and R 4 Examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms represented by the formula (I) include a monovalent chain hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 10 carbon atoms, and a monovalent aromatic hydrocarbon group having 6 to 10 carbon atoms.

[0027] R1 is preferably a fluorine atom in terms of the acidity of the generated acid, and R 2 is preferably a fluorine atom, a trifluoromethyl group or a hydrogen atom. R 3 and R 4 are each independently preferably a hydrogen atom, a fluorine atom or a trifluoromethyl group.

[0028] m is preferably 0 to 8, more preferably 0 to 2, and particularly preferably 0 or 1.

[0029] A 1 and A 2 The divalent cyclic organic group having 3 to 20 ring members represented by the formula (I) is not particularly limited as long as it is a group obtained by removing two hydrogen atoms from a cyclic structure having the above number of ring members. Examples of the cyclic structure include an alicyclic structure having 3 to 20 carbon atoms, an aromatic ring structure having 6 to 20 carbon atoms, a cyclic ether structure having 3 to 20 ring members, a lactone structure, a cyclic carbonate structure, a sultone structure, and a thioxane structure. These cyclic structures may be substituted with a monovalent organic group such as an alkoxy group or an alkoxycarbonyl group, a halogen atom, a hydroxy group, a cyano group, or the like. The term "organic group" refers to a group having at least one carbon atom.

[0030] Examples of the alicyclic structure having 3 to 20 carbon atoms include an alicyclic monocyclic structure having 3 to 20 carbon atoms and an alicyclic polycyclic structure having 6 to 20 carbon atoms. The alicyclic monocyclic structure having 3 to 20 carbon atoms and the alicyclic polycyclic structure having 6 to 20 carbon atoms may be either a saturated hydrocarbon structure or an unsaturated hydrocarbon structure. The alicyclic polycyclic structure may be either a bridged alicyclic hydrocarbon structure or a fused alicyclic hydrocarbon structure. The bridged alicyclic hydrocarbon group refers to a polycyclic alicyclic hydrocarbon group in which two non-adjacent carbon atoms constituting an alicyclic ring are bonded by a bond chain containing one or more carbon atoms. The fused alicyclic hydrocarbon structure refers to a polycyclic alicyclic hydrocarbon structure in which multiple alicyclic rings share a side (a bond between two adjacent carbon atoms).

[0031] Among the alicyclic monocyclic structures, preferred saturated hydrocarbon structures include cyclopentane, cyclohexane, cycloheptane, and cyclooctane, and preferred unsaturated hydrocarbon structures include cyclopentene, cyclohexene, cycloheptene, cyclooctene, and cyclodecene. Preferred alicyclic polycyclic structures include bridged alicyclic saturated hydrocarbon structures, such as bicyclo[2.2.1]heptane (norbornane), bicyclo[2.2.2]octane, and tricyclo[3.3.1.1]. 3,7 ] Decane (adamantane) and the like are preferred.

[0032] Examples of the aromatic ring structure having 6 to 20 carbon atoms include benzene, naphthalene, anthracene, indene, and fluorene.

[0033] A 2 Examples of the divalent chain hydrocarbon group having 1 to 10 carbon atoms represented by the formula (I) include a linear or branched saturated hydrocarbon group, and a linear or branched unsaturated hydrocarbon group.

[0034] A 1 is preferably a single bond, and A 2 is preferably a methylene group, an adamantanediyl group, a phenylene group, a fluorophenylene group, or the like. Furthermore, n is preferably 0 or 1.

[0035] R 5 represents a group represented by the above formula (1-1) or a group represented by the above formula (1-2), and is an acid-dissociable group. R in the above formula (1-1) 1A , R 1B and R 1C and R in the above formula (1-2) 2A and R 2B In the formula (I), examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

[0036] In the above formula (1-1), R 1B and R 1CExamples of the divalent cyclic organic group having 3 to 20 ring members formed by combining these together with the carbon atoms to which they are bonded include A 1 and A 2 Examples of the divalent cyclic organic group having 3 to 20 carbon atoms and represented by the following formula are given below.

[0037] In the above formula (1-2), R 2A and R 2B Examples of the divalent cyclic organic group having 4 to 20 ring members formed by combining together with the atomic chain to which they are bonded include groups in which two hydrogen atoms have been removed from a cyclic structure such as a cyclic ether structure, a cyclic thioether structure, or a thioxane structure.

[0038] Specific examples of the group represented by the above formula (1-1) include structures of the following formulae (1-1-1) to (1-1-8).

[0039] [ka]

[0040] (In the above formula, R 1A and * are the same as in formula (1-1) above. 1B R is a monovalent hydrocarbon group having 1 to 20 carbon atoms. 1C1 represents a linear or branched hydrocarbon group having 1 to 20 carbon atoms. 1D represents a hydrogen atom, a halogen atom, a hydroxy group, a cyano group, a hydrocarbon group having 1 to 10 carbon atoms, or a group represented by the following formula (1-A) or (1-B). p1 represents an integer of 0 to 5. p2 represents an integer of 0 to 5.

[0041] [ka]

[0042] (In the above formula (1-A), L 1 R is a divalent linking group selected from -O-, -CO-, -COO-, -OCO-, -O-CO-O-, -S-, -SO2-, -CONH-, and -NHCO-. 1Eis a hydrocarbon group having 1 to 10 carbon atoms, a fluorinated hydrocarbon group having 1 to 10 carbon atoms, a lactone group, a sultone group, or a cyclic carbonate group. In the above formula (1-B), Y 1 and Y 2 are each independently -O- or -S-. 1F is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R 1G is a monovalent hydrocarbon group having 1 to 20 carbon atoms, or R 1F and R 1G represents a divalent cyclic organic group having 4 to 20 ring members, which is formed by combining together with the atomic chain to which they are bonded. ** indicates the site of bonding to the cyclic structures of the above formulas (1-1-1) to (1-1-7).

[0043] Specific examples of the group represented by the above formula (1-2) include structures of the following formulae (1-2-1) to (1-2-4).

[0044] [ka]

[0045] (In the above formula, R 2A is the same as the above formula (1-2).

[0046] In the above formula (1), the above Z + Examples of the monovalent radiation-sensitive onium cation represented by the formula (X-1) include radiation-decomposable onium cations containing elements such as S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, and Bi, such as sulfonium cation, tetrahydrothiophenium cation, iodonium cation, phosphonium cation, diazonium cation, and pyridinium cation. Among these, sulfonium cation or iodonium cation is preferred. The sulfonium cation or iodonium cation is preferably represented by the following formulas (X-1) to (X-6).

[0047] [ka]

[0048] In the above formula (X-1), R a1 , R a2 and R a3 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, an alkoxy group or an alkoxycarbonyloxy group, 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, -OSO2-R P , -SO2-R Q or -SR T or a ring structure formed by combining two or more of these groups. The ring structure may contain a heteroatom such as O or S between the carbon-carbon bonds that form the skeleton. R P , R Q and R T are each 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 an integer of 0 to 5. R a1 ~R a3 and R P , R Q and R T If there are multiple R a1 ~R a3 and R P , R Q and R T may be the same or different.

[0049] In the above formula (X-2), R b1 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, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms, or a hydroxy group. k is 0 or 1. n kWhen is 0, k4 is an integer from 0 to 4, and n k When is 1, k4 is an integer between 0 and 7. R b1 If there are multiple, multiple R b1 may be the same or different, and multiple R b1 R may represent a ring structure formed by combining with each other. b2 L is a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. C is a single bond or a divalent linking group. k5 is an integer of 0 to 4. R b2 If there are multiple, multiple R b2 may be the same or different, and multiple R b2 may represent a ring structure formed by combining with each other, and q is an integer of 0 to 3. In the formula, S + The ring structure containing may contain a heteroatom such as O or S between the carbon-carbon bonds that form the skeleton.

[0050] 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.

[0051] In the above formula (X-4), R g1 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, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms, or a hydroxy group. k is 0 or 1. n k2 When is 0, k10 is an integer between 0 and 4, and n k2 When is 1, k10 is an integer between 0 and 7. R g1 If there are multiple, multiple R g1 may be the same or different, and multiple R g1 R may represent a ring structure formed by combining with each other. g2 and R g3are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, an alkoxy group or an alkoxycarbonyloxy group, 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 a ring structure formed by combining these groups together. k11 and k12 are each independently an integer of 0 to 4. R g2 and R g3 If there are multiple R g2 and R g3 may be the same or different.

[0052] In the above formula (X-5), R d1 and R d2 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, an alkoxy group or an alkoxycarbonyl group, 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, or a nitro group, or a ring structure formed by combining two or more of these groups. k6 and k7 are each independently an integer of 0 to 5. R d1 and R d2 If there are multiple R d1 and R d2 may be the same or different.

[0053] In the above formula (X-6), R e1 and R e2 are each independently 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.

[0054] Specific examples of the radiation-sensitive onium cation include, but are not limited to, structures of the following formulas:

[0055] [ka]

[0056] [ka]

[0057] In compound (1), the lower limit of the rate of change in van der Waals volume of the anionic structure before and after cleavage of the acid-dissociable group represented by formula (i) is 32%, preferably 38%, more preferably 40%, and particularly preferably 45%. The upper limit of the rate of change is 67%, preferably 65%, more preferably 62%, and particularly preferably 60%. When the rate of change in van der Waals volume is within this range, a radiation-sensitive resin composition with a sufficiently small LWR and CDU can be obtained, and a well-balanced sensitivity and lithography performance can be obtained. The van der Waals volumes of the anionic structure of compound (1) and the structure after cleavage of the acid-dissociable group of the anionic structure by acid generated by irradiation with actinic rays or radiation can each be calculated; specifically, they are calculated using RDKit, an open-source chemoinformatics software.

[0058] Furthermore, in compound (1), the change in ClogP value (absolute value of the difference in ClogP value) between the structure before and after cleavage of the acid-dissociable group represented by formula (ii) is 3.00 or less, preferably 2.50 or less, and more preferably 2.00 or less. A small change in ClogP value reduces solubility variation during development, resulting in a radiation-sensitive resin composition with sufficiently small LWR and CDU. The ClogP value is determined by calculation, specifically, using Chemdraw (CambridgeSoft, Ver. 12).

[0059] Specific examples of compound (1) include onium salt compounds represented by the following formulas (B-1) to (B-22) (hereinafter, the onium salt compounds represented by the following formulas (B-1) to (B-22) may also be referred to as "compound (B-1) to compound (B-22)").

[0060] [ka]

[0061] [ka]

[0062] The lower limit of the content of compound (1) (when multiple types of compound (1) are contained, the total amount thereof) is preferably 0.02 parts by mass, more preferably 0.1 parts by mass, even more preferably 1 part by mass, and particularly preferably 5 parts by mass, per 100 parts by mass of the resin described below. The upper limit of the content is preferably 50 parts by mass, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less. The content of compound (1) is appropriately selected depending on the type of resin used, exposure conditions, desired sensitivity, and the like. This allows for excellent sensitivity, LWR performance, CDU performance, and pattern rectangularity to be exhibited during resist pattern formation.

[0063] (resin) The resin is an aggregate of polymers having a structural unit containing an acid-dissociable group (hereinafter also referred to as "structural unit (I)") (hereinafter also referred to as "base resin"). The "acid-dissociable group" refers to a group that substitutes a hydrogen atom in a carboxy group, a phenolic hydroxyl group, an alcoholic hydroxyl group, a sulfo group, or the like, and that dissociates under the action of an acid. The radiation-sensitive resin composition has excellent pattern formability because the resin contains the structural unit (I).

[0064] In addition to the structural unit (I), the base resin preferably has a structural unit (II) containing at least one selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure, which will be described later, and may also have structural units other than the structural units (I) and (II). Each structural unit will be described below.

[0065] Structural Units The structural unit (I) is a structural unit containing an acid-dissociable group. The structural unit (I) is not particularly limited as long as it contains an acid-dissociable group, and examples thereof include a structural unit having a tertiary alkyl ester moiety, a structural unit having a structure in which the hydrogen atom of a phenolic hydroxyl group is substituted with a tertiary alkyl group, and a structural unit having an acetal bond. From the viewpoint of improving the pattern formability of the radiation-sensitive resin composition, a structural unit represented by the following formula (2) (hereinafter also referred to as "structural unit (I-1)") is preferred.

[0066] [ka]

[0067] In the above formula (2), R 6 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 7 R is a monovalent hydrocarbon group having 1 to 20 carbon atoms. 8 and R 9 are each independently a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R 8 and R 9 are combined with each other and formed together with the carbon atoms to which they are bonded to form a divalent alicyclic group having 3 to 20 carbon atoms.

[0068] Above R 6 As the alkyl group, from the viewpoint of copolymerizability of the monomer that gives the structural unit (I-1), a hydrogen atom or a methyl group is preferred, and a methyl group is more preferred.

[0069] Above R 7 Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) include a chain hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

[0070] Above R 7 ~R 9Examples of the chain hydrocarbon group having 1 to 10 carbon atoms represented by the formula include a linear or branched saturated hydrocarbon group having 1 to 10 carbon atoms, and a linear or branched unsaturated hydrocarbon group having 1 to 10 carbon atoms.

[0071] Above R 7 ~R 9 The alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by the formula (1) is 1 and A 2 A group in which one hydrogen atom has been removed from the structure shown as the alicyclic structure having 3 to 20 carbon atoms in the above formula (1) can be suitably used.

[0072] Above R 7 As the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms represented by the formula (1), 1 and A 2 A group in which one hydrogen atom has been removed from the structure shown as the aromatic ring structure having 6 to 20 carbon atoms in the above formula (1) can be suitably used.

[0073] Above R 7 As the alkyl group, a linear or branched saturated hydrocarbon group having 1 to 10 carbon atoms, or an alicyclic hydrocarbon group having 3 to 20 carbon atoms is preferred.

[0074] Above R 8 and R 9 The divalent alicyclic group having 3 to 20 carbon atoms formed by combining these together with the carbon atoms to which they are bonded is not particularly limited as long as it is a group formed by removing two hydrogen atoms from the same carbon atom constituting a carbon ring of a monocyclic or polycyclic alicyclic hydrocarbon having the above carbon number. Either a monocyclic hydrocarbon group or a polycyclic hydrocarbon group may be used, and the polycyclic hydrocarbon group may be either a bridged alicyclic hydrocarbon group or a fused alicyclic hydrocarbon group, and may be either a saturated hydrocarbon group or an unsaturated hydrocarbon group. Note that a fused alicyclic hydrocarbon group refers to a polycyclic alicyclic hydrocarbon group formed in such a way that multiple alicyclic rings share a side (a bond between two adjacent carbon atoms).

[0075] Among the monocyclic alicyclic hydrocarbon groups, preferred saturated hydrocarbon groups include cyclopentanediyl, cyclohexanediyl, cycloheptanediyl, and cyclooctanediyl groups, while preferred unsaturated hydrocarbon groups include cyclopentenediyl, cyclohexenediyl, cycloheptenediyl, cyclooctenediyl, and cyclodecenediyl groups. Preferred polycyclic alicyclic hydrocarbon groups include bridged alicyclic saturated hydrocarbon groups, such as bicyclo[2.2.1]heptane-2,2-diyl (norbornane-2,2-diyl), bicyclo[2.2.2]octane-2,2-diyl, and tricyclo[3.3.1.1]heptane-2,2-diyl. 3,7 ]Decane-2,2-diyl group (adamantane-2,2-diyl group) and the like are preferred.

[0076] Among these, R 7 is an alkyl group having 1 to 4 carbon atoms, and R 8 and R 9 The alicyclic structure formed by combining these together with the carbon atoms to which they are bonded is preferably a polycyclic or monocyclic cycloalkane structure.

[0077] Examples of the structural unit (I-1) include structural units represented by the following formulas (2-1) to (2-6) (hereinafter also referred to as "structural units (I-1-1) to (I-1-6)").

[0078] [ka]

[0079] In the above formulas (2-1) to (2-6), R 6 ~R 9 has the same meaning as in the above formula (2). i and j each independently represent an integer of 1 to 4. k and l are 0 or 1.

[0080] i and j are preferably 1. 7 R is preferably a methyl group, an ethyl group, or an isopropyl group. 8 and R 9 As the alkyl group, a methyl group or an ethyl group is preferred.

[0081] The base resin may contain one type of structural unit (I) or a combination of two or more types.

[0082] The content of the structural unit (I) (the total content when multiple types are included) relative to all structural units constituting the base resin 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. Also, 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 the structural unit (I) within the above range, the pattern formability of the radiation-sensitive resin composition can be further improved.

[0083] [Structural unit (II)] The structural unit (II) is a structural unit containing at least one selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure. By further including the structural unit (II), the base resin can adjust its solubility in a developer, thereby improving the lithography performance, such as resolution, of the radiation-sensitive resin composition. Furthermore, the adhesion between a resist pattern formed from the base resin and a substrate can be improved.

[0084] Examples of the structural unit (II) include structural units represented by the following formulas (3-1) to (3-10).

[0085] [ka]

[0086] In the above formula, R L1 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. L2 ~R L5 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a cyano group, a trifluoromethyl group, a methoxy group, a methoxycarbonyl group, a hydroxy group, a hydroxymethyl group, or a dimethylamino group. L4and R L5 and may be combined together to form a divalent alicyclic group having 3 to 8 carbon atoms 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. p is an integer of 0 to 3. q is an integer of 1 to 3.

[0087] Above R L4 and R L5 Examples of the divalent alicyclic group having 3 to 8 carbon atoms formed by combining these together with the carbon atoms to which they are bonded include R 8 and R 9 Examples include divalent alicyclic groups having 3 to 20 carbon atoms, which are formed by combining chain hydrocarbon groups or alicyclic hydrocarbon groups represented by the following formula (I) together with the carbon atoms to which they are bonded, and which have 3 to 8 carbon atoms. One or more hydrogen atoms on this alicyclic group may be substituted with a hydroxy group.

[0088] The above L 2 Examples of the divalent linking group represented by the formula (I) include a divalent linear or branched hydrocarbon group having 1 to 10 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms, or a group composed of one or more of these hydrocarbon groups and at least one group selected from -CO-, -O-, -NH-, and -S-.

[0089] Of these, the structural unit (II) is preferably a structural unit containing a lactone structure, more preferably a structural unit containing a norbornane lactone structure, and even more preferably a structural unit derived from norbornane lactone-yl (meth)acrylate.

[0090] The content of the structural unit (II) is preferably 20 mol% or more, more preferably 30 mol% or more, and even more preferably 35 mol% or more, based on all structural units constituting the base resin. It is also preferably 75 mol% or less, more preferably 70 mol% or less, and even more preferably 65 mol% or less. By setting the content of the structural unit (II) within the above range, the radiation-sensitive resin composition can further improve lithography performance such as resolution and adhesion of the formed resist pattern to the substrate.

[0091] [Structural unit (III)] The base resin optionally contains other structural units in addition to the structural units (I) and (II). Examples of the other structural units include a structural unit (III) containing a polar group (excluding those corresponding to the structural unit (II)). By further containing the structural unit (III), the base resin can adjust its solubility in a developer, thereby improving the lithography performance, such as resolution, of the radiation-sensitive resin composition. Examples of the polar group include a hydroxy group, a carboxy group, a cyano group, a nitro group, and a sulfonamide group. Among these, a hydroxy group and a carboxy group are preferred, and a hydroxy group is more preferred.

[0092] Examples of the structural unit (III) include structural units represented by the following formula:

[0093] [ka]

[0094] In the above formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0095] When the base resin has the structural unit (III) having the polar group, the content of the structural unit (III) is preferably 5 mol% or more, more preferably 8 mol% or more, and even more preferably 10 mol% or more, based on the total structural units constituting the base resin. Also, the content is preferably 40 mol% or less, more preferably 35 mol% or less, and even more preferably 30 mol% or less. By setting the content of the structural unit (III) within the above range, the lithography performance, such as resolution, of the radiation-sensitive resin composition can be further improved.

[0096] Structural Unit (IV) In addition to the structural unit (III) having the polar group, the base resin optionally contains a structural unit derived from hydroxystyrene or a structural unit having a phenolic hydroxyl group (hereinafter, both of these are collectively referred to as "structural unit (IV)"). The structural unit (IV) contributes to improving etching resistance and the difference in developer solubility (dissolution contrast) between exposed and unexposed areas. This resin is particularly suitable for pattern formation using exposure to radiation with a wavelength of 50 nm or less, such as electron beams or EUV. In this case, the resin preferably contains the structural unit (I) in addition to the structural unit (IV).

[0097] In this case, it is preferable to carry out polymerization in a state in which the phenolic hydroxyl group is protected with a protecting group such as an alkali-labile group, and then to obtain structural unit (IV) by deprotection through hydrolysis. The structural unit that gives structural unit (IV) upon hydrolysis is preferably represented by the following formula (4-1) or (4-2).

[0098] [ka]

[0099] In the above formulas (4-1) and (4-2), R 11 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.12 The monovalent hydrocarbon group having 1 to 20 carbon atoms is R 8 Examples of the alkoxy group include a methoxy group, an ethoxy group, and a tert-butoxy group.

[0100] Above R 12 As the alkyl group, an alkyl group and an alkoxy group are preferred, and among these, a methyl group and a tert-butoxy group are more preferred.

[0101] In the case of a resin intended for exposure to radiation having a wavelength of 50 nm or less, the content of the structural unit (IV) is preferably 10 mol % or more, more preferably 20 mol % or more, based on the total structural units constituting the resin, and is preferably 70 mol % or less, more preferably 60 mol % or less.

[0102] (Method for synthesizing base resin) The base resin can be synthesized, for example, by polymerizing monomers that provide the respective structural units in an appropriate solvent using a radical polymerization initiator or the like.

[0103] Examples of the radical polymerization initiator include azo 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 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 alone or in combination of two or more.

[0104] Examples of the solvent used in the polymerization include Alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane; cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, and norbornane; Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, and cumene; Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, and chlorobenzene; Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate, and methyl propionate; Ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone, and 2-heptanone; ethers such as tetrahydrofuran, dimethoxyethanes, and diethoxyethanes; Examples of the solvent include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 4-methyl-2-pentanol, etc. These solvents used in the polymerization may be used alone or in combination of two or more.

[0105] The reaction temperature in the polymerization is usually 40° C. to 150° C., and preferably 50° C. to 120° C. The reaction time is usually 1 hour to 48 hours, and preferably 1 hour to 24 hours.

[0106] The molecular weight of the base resin is not particularly limited, but the lower limit of the weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) is preferably 1,000, more preferably 2,000, even more preferably 3,000, and particularly preferably 4,000. The upper limit of Mw is preferably 50,000, more preferably 30,000, even more preferably 15,000, and particularly preferably 12,000. If the Mw of the base resin is below the lower limit, the heat resistance of the resulting resist film may be reduced. If the Mw of the base resin is above the upper limit, the developability of the resist film may be reduced.

[0107] The ratio (Mw / Mn) of Mw to the polystyrene-equivalent number average molecular weight (Mn) of the base resin as determined by GPC is usually 1 or more and 5 or less, preferably 1 or more and 3 or less, and more preferably 1 or more and 2 or less.

[0108] The Mw and Mn of the resin in this specification are values ​​measured using gel permeation chromatography (GPC) under the following conditions.

[0109] GPC columns: 2 G2000HXL, 1 G3000HXL, 1 G4000HXL (all manufactured by Tosoh) Column temperature: 40℃ Elution 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

[0110] The content of the base resin is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 85% by mass or more, based on the total solid content of the radiation-sensitive resin composition.

[0111] (other resins) The radiation-sensitive resin composition of this embodiment may contain, as an additional resin, a resin having a higher mass content of fluorine atoms than the base resin (hereinafter also referred to as a "high-fluorine-content resin"). When the radiation-sensitive resin composition contains a high-fluorine-content resin, the high-fluorine-content resin can be unevenly distributed in the surface layer of the resist film relative to the base resin, which can result in increased water repellency on the surface of the resist film during immersion exposure and control of the components in the resist film to a desired state.

[0112] The high-fluorine content resin preferably has, for example, a structural unit represented by the following formula (5) (hereinafter also referred to as "structural unit (V)"), and may also have the structural unit (I) or structural unit (III) of the above-mentioned base resin, as necessary.

[0113] [ka]

[0114] In the above formula (5), R 13 is a hydrogen atom, a methyl group, or a trifluoromethyl group. L is a single bond, an oxygen atom, a sulfur atom, -COO-, -SO2ONH-, -CONH- or -OCONH-. 14 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.

[0115] Above R 13 As the alkyl group, from the viewpoint of copolymerizability of the monomer that gives the structural unit (V), a hydrogen atom or a methyl group is preferred, and a methyl group is more preferred.

[0116] Above G L As the group, from the viewpoint of copolymerizability of the monomer that gives the structural unit (V), a single bond and -COO- are preferred, and -COO- is more preferred.

[0117] Above R 14 Examples of the monovalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms represented by the formula include a linear or branched alkyl group having 1 to 20 carbon atoms in which some or all of the hydrogen atoms have been substituted with fluorine atoms.

[0118] Above R 14 Examples of the monovalent fluorinated alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by the formula (I) include a monocyclic or polycyclic hydrocarbon group having 3 to 20 carbon atoms in which some or all of the hydrogen atoms have been substituted with fluorine atoms.

[0119] Above R 14 As the alkyl group, a fluorinated chain hydrocarbon group is preferable, a fluorinated alkyl group is more preferable, and 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 are even more preferable.

[0120] When the high-fluorine-content resin has the structural unit (V), the content of the structural unit (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, based on the total structural units constituting the high-fluorine-content resin. Also, the content 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 the structural unit (V) within the above range, the mass content of fluorine atoms in the high-fluorine-content resin can be more appropriately adjusted, further promoting uneven distribution of fluorine atoms in 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.

[0121] The high-fluorine-content resin may have a fluorine atom-containing structural unit represented by the following formula (f-2) (hereinafter also referred to as structural unit (VI)) in addition to or instead of the structural unit (V): By having the structural unit (f-2), the high-fluorine-content resin has improved solubility in an alkaline developer, and can suppress the occurrence of development defects.

[0122] [ka]

[0123] The structural unit (VI) is roughly classified into two types: (x) a case having an alkali-soluble group, and (y) a case having a group that dissociates under the action of alkali to increase the solubility in an alkali developer (hereinafter simply referred to as an "alkali-dissociable group"). In both (x) and (y), R C R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. D is a single bond, a hydrocarbon group having 1 to 20 carbon atoms and a valence of (s+1), and R of this hydrocarbon group E Oxygen atom, sulfur atom, -NR dd -, a carbonyl group, -COO-, or -CONH- is bonded to the hydrocarbon group, or a structure in which some of the hydrogen atoms in the hydrocarbon group are substituted with an organic group having a hetero atom. ddis a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. s is an integer of 1 to 3.

[0124] When the structural unit (VI) has (x) an alkali-soluble group, R F is a hydrogen atom, and A 1 is an oxygen atom, -COO-* or -SO2O-*. * is R F The binding site of W is shown. 1 A is a single bond, a hydrocarbon group having 1 to 20 carbon atoms, or a divalent fluorinated hydrocarbon group. 1 is an oxygen atom, W 1 is A 1 is a fluorinated hydrocarbon group having a fluorine atom or a fluoroalkyl group on the carbon atom to which R is bonded. E is a single bond or a divalent organic group having 1 to 20 carbon atoms. When s is 2 or 3, multiple R E , W 1 , A 1 and R F may be the same or different. When the structural unit (VI) has (x) an alkali-soluble group, it is possible to increase the affinity for an alkaline developer and suppress development defects. As the structural unit (VI) having (x) an alkali-soluble group, A 1 is an oxygen atom and W 1 It is particularly preferred that is a 1,1,1,3,3,3-hexafluoro-2,2-methanediyl group.

[0125] When the structural unit (VI) has an alkali-dissociable group (y), R F is a monovalent organic group having 1 to 30 carbon atoms, and A 1 is an oxygen atom, -NR aa -, -COO-* or -SO2O-*. R aa is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. * is R F The binding site of W is shown. 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 When is -COO-* or -S02O-*, W 1or R F is A 1 A has a fluorine atom on the carbon atom bonded to or adjacent to A. 1 is an oxygen atom, W 1 , R E is a single bond, and R D R is a hydrocarbon group with 1 to 20 carbon atoms E A carbonyl group is bonded to the end of the R F is an organic group having a fluorine atom. When s is 2 or 3, multiple R E , W 1 , A 1 and R F may be the same or different. When the structural unit (VI) has (y) an alkali-dissociable group, the surface of the resist film changes from hydrophobic to hydrophilic in the alkaline development step. As a result, the affinity to the developer is significantly increased, and development defects can be more efficiently suppressed. As the structural unit (VI) having (y) an alkali-dissociable group, A 1 is -COO-* and R F Or W 1 It is particularly preferred that both of them have a fluorine atom.

[0126] R C As the alkyl group, from the viewpoint of copolymerizability of the monomer that gives the structural unit (VI), a hydrogen atom and a methyl group are preferred, and a methyl group is more preferred.

[0127] R E When is a divalent organic group, it is preferably a group having a lactone structure, more preferably a group having a polycyclic lactone structure, and more preferably a group having a norbornane lactone structure.

[0128] When the high-fluorine-content resin has the structural unit (VI), the content of the structural unit (VI) is preferably 40 mol% or more, more preferably 50 mol% or more, and even more preferably 60 mol% or more, based on all structural units constituting the high-fluorine-content resin. Also, 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 the structural unit (VI) within the above range, the water repellency of the resist film during immersion exposure can be further improved.

[0129] Other structural units The high fluorine content resin may contain a structural unit having an alicyclic structure represented by the following formula (6) as a structural unit other than the structural units listed above. [ka] (In the above formula (6), R 1α is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 2α is a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms.

[0130] In the above formula (6), R 2α The monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by the formula (1) is 3 A monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms in the above formula can be suitably used.

[0131] When the high-fluorine-content resin contains the structural unit having the alicyclic structure, the content of the structural unit having the alicyclic structure is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 30 mol% or more, based on the total structural units constituting the high-fluorine-content resin, and is preferably 70 mol% or less, more preferably 60 mol% or less, and even more preferably 50 mol% or less.

[0132] The lower limit of Mw of the high-fluorine-content resin is preferably 1,000, more preferably 2,000, further preferably 3,000, and particularly preferably 5,000. The upper limit of Mw is preferably 50,000, more preferably 30,000, further preferably 20,000, and particularly preferably 15,000.

[0133] The Mw / Mn of the high fluorine content resin is usually 1 or more, more preferably 1.1 or more, and usually 5 or less, preferably 3 or less, more preferably 2 or less, and even more preferably 1.9 or less.

[0134] The content of the high-fluorine content 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, relative to 100 parts by mass of the base resin, and is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, even more preferably 8 parts by mass or less, and particularly preferably 5 parts by mass or less.

[0135] By setting the content of the high-fluorine-containing resin within the above range, the high-fluorine-containing resin can be more effectively distributed unevenly on the surface layer of the resist film, thereby further improving the water repellency of the surface of the resist film during immersion lithography. The radiation-sensitive resin composition may contain one or more high-fluorine-containing resins.

[0136] (Method for synthesizing high fluorine content resin) The high fluorine content resin can be synthesized by the same method as the above-mentioned method for synthesizing the base resin.

[0137] (photodegradable base) The radiation-sensitive resin composition of the present invention contains a photodegradable base as an acid diffusion controller. The acid diffusion controller controls the diffusion phenomenon of the acid generated from compound (1) in the resist film upon exposure, thereby suppressing undesirable chemical reactions in unexposed areas. The acid diffusion controller also improves the storage stability of the resulting radiation-sensitive resin composition. Furthermore, the resolution of the resist pattern is further improved, and changes in the line width of the resist pattern due to variations in the exposure time until development can be suppressed, resulting in a radiation-sensitive resin composition with excellent process stability.

[0138] The photodegradable base is an onium salt compound that generates a weak acid upon exposure, and the generated acid is a weak acid that does not induce dissociation of the acid-dissociable group in the resin under normal conditions. In this specification, "normal conditions" refers to post-exposure baking at 110°C for 60 seconds.

[0139] The photodegradable base functions as an acid diffusion controller in unexposed areas due to its basicity, but in exposed areas, a weak acid is generated from the protons produced by decomposition of the radiation-sensitive onium cation and the anion of the weak acid, resulting in a decrease in acid diffusion controllability. Therefore, the acid generated in the exposed areas efficiently dissociates the acid-dissociable groups of the resin and compound (1), while the acid does not diffuse in the unexposed areas, leaving the resin and compound (1) unchanged. This results in a more pronounced difference in solubility between the exposed and unexposed areas, resulting in a resist film with even better LWR performance, CDU performance, and pattern rectangularity.

[0140] Examples of the photodegradable base include sulfonium salt compounds represented by the following formula (7-1) and iodonium salt compounds represented by the following formula (7-2).

[0141] [ka]

[0142] In the above formula (7-1) and formula (7-2), J + is a sulfonium cation, and U + is the iodonium cation. - and Q -are each independently OH - , R α -COO - , R α -SO3 - The cation and anion moieties may be bonded not only by an ionic bond but also by a coordinate bond or a covalent bond. α is an alkyl group, an aryl group, or an aralkyl group. α A hydrogen atom in the aromatic ring of the aryl group or aralkyl group represented by the following formula may be substituted with a hydroxy group, a fluorine atom-substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.

[0143] Above J + Examples of the sulfonium cation represented by the formula (X-1) to (X-4) include the sulfonium cations represented by the formula (X-1) to (X-4). Above U + Examples of the iodonium cation represented by the formula (X-5) to (X-6) include the iodonium cation represented by the formula (X-6).

[0144] Examples of the photodegradable base include compounds represented by the following formula:

[0145] [ka]

[0146] Of these, the photodegradable base is preferably a sulfonium salt, more preferably a triarylsulfonium salt, and even more preferably triphenylsulfonium salicylate and triphenylsulfonium 10-camphorsulfonate.

[0147] The lower limit of the content of the photodegradable base is preferably 3 parts by mass, more preferably 4 parts by mass, and even more preferably 5 parts by mass, relative to 100 parts by mass of the total of the radiation-sensitive acid generator (including compound (1)). The upper limit of the content is preferably 80 parts by mass, more preferably 70 parts by mass, and even more preferably 50 parts by mass.

[0148] By setting the content of the photodegradable base within the above range, the lithography performance of the radiation-sensitive resin composition can be further improved. The radiation-sensitive resin composition may contain one or more types of photodegradable bases.

[0149] (solvent) The radiation-sensitive resin composition according to this embodiment contains a solvent. The solvent is not particularly limited as long as it can dissolve or disperse at least Compound (1) and the resin, as well as the radiation-sensitive acid generator and other components that may be optionally contained therein.

[0150] Examples of the solvent include alcohol-based solvents, ether-based solvents, ketone-based solvents, amide-based solvents, ester-based solvents, and hydrocarbon-based solvents.

[0151] Examples of alcohol-based solvents include: Monoalcohol solvents having 1 to 18 carbon atoms, such as iso-propanol, 4-methyl-2-pentanol, 3-methoxybutanol, n-hexanol, 2-ethylhexanol, furfuryl alcohol, cyclohexanol, 3,3,5-trimethylcyclohexanol, and diacetone alcohol; polyhydric alcohol solvents having 2 to 18 carbon atoms, such as ethylene glycol, 1,2-propylene glycol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, and tripropylene glycol; Examples of suitable polyhydric alcohol solvents include partially etherified polyhydric alcohol solvents in which some of the hydroxy groups of the above polyhydric alcohol solvents have been etherified.

[0152] Examples of ether solvents include: dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether; cyclic ether solvents such as tetrahydrofuran and tetrahydropyran; Aromatic ring-containing ether solvents such as diphenyl ether and anisole (methyl phenyl ether); Examples of the polyhydric alcohol solvent include polyhydric alcohol ether solvents obtained by etherifying the hydroxy groups of the above polyhydric alcohol solvents.

[0153] Examples of ketone solvents include chain ketone solvents such as acetone, butanone, and methyl-iso-butyl ketone: Cyclic ketone solvents such as cyclopentanone, cyclohexanone, and methylcyclohexanone: Examples include 2,4-pentanedione, acetonylacetone, and acetophenone.

[0154] Examples of the amide solvent include cyclic amide solvents such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone; Examples of the solvent include chain amide solvents such as N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, and N-methylpropionamide.

[0155] Examples of ester solvents include: 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; Examples of the solvent include polycarboxylic acid diester solvents such as propylene glycol diacetate, methoxytriglycol acetate, diethyl oxalate, ethyl acetoacetate, ethyl lactate, and diethyl phthalate.

[0156] Examples of hydrocarbon solvents include Aliphatic hydrocarbon solvents such as n-hexane, cyclohexane, and methylcyclohexane; Examples of the solvent include aromatic hydrocarbon solvents such as benzene, toluene, di-isopropylbenzene, and n-amylnaphthalene.

[0157] Among these, ester-based solvents and ketone-based solvents are preferred, polyhydric alcohol partial ether acetate-based solvents, cyclic ketone-based solvents and lactone-based 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.

[0158] (Other optional ingredients) The radiation-sensitive resin composition may contain other optional components in addition to the above components. Examples of the other optional components include a radiation-sensitive photoacid generator other than compound (1), an acid diffusion controller other than a photodegradable base, a crosslinking agent, a localization promoter, a surfactant, an alicyclic skeleton-containing compound, and a sensitizer. These other optional components may be used alone or in combination of two or more.

[0159] Examples of acid diffusion controllers other than photodegradable bases include compounds represented by the following formula (8) (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, and nitrogen-containing heterocyclic compounds.

[0160] [ka]

[0161] In the above formula (8), R 22 , R 23 and R 24 are each 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.

[0162] Examples of the nitrogen-containing compound (I) include monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; trialkylamines such as triethylamine; and aromatic amines such as aniline.

[0163] Examples of the nitrogen-containing compound (II) include ethylenediamine and N,N,N',N'-tetramethylethylenediamine.

[0164] Examples of the nitrogen-containing compound (III) include polyamine compounds such as polyethyleneimine and polyallylamine; polymers such as dimethylaminoethylacrylamide; and the like.

[0165] Examples of the amide group-containing compound include formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, benzamide, pyrrolidone, and N-methylpyrrolidone.

[0166] Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, and tributylthiourea.

[0167] Examples of the nitrogen-containing heterocyclic compound include pyridines such as pyridine and 2-methylpyridine; morpholines such as N-propylmorpholine and N-(undecylcarbonyloxyethyl)morpholine; pyrazine, pyrazole, and the like.

[0168] Furthermore, as the nitrogen-containing organic 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 Nt-butoxycarbonylpiperidine, Nt-butoxycarbonylimidazole, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenzimidazole, N-(t-butoxycarbonyl)di-n-octylamine, N-(t-butoxycarbonyl)diethanolamine, N-(t-butoxycarbonyl)dicyclohexylamine, N-(t-butoxycarbonyl)diphenylamine, Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-butoxycarbonyl-4-acetoxypiperidine, and Nt-amyloxycarbonyl-4-hydroxypiperidine.

[0169] <Method for preparing radiation-sensitive resin composition> The radiation-sensitive resin composition can be prepared, for example, by mixing compound (1), a resin, a photodegradable base, and optionally a high-fluorine-content resin, and a solvent in a predetermined ratio. After mixing, the radiation-sensitive resin composition is preferably filtered, for example, through a filter having a pore size of about 0.05 μm to 0.20 μm. The solids concentration of the 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.

[0170] <Pattern formation method> A pattern forming method according to one embodiment of the present invention includes: a step (1) of directly or indirectly applying the radiation-sensitive resin composition onto a substrate to form a resist film (hereinafter also referred to as a "resist film forming step"); a step (2) of exposing the resist film to light (hereinafter also referred to as the "exposure step"); The method includes a step (3) of developing the exposed resist film (hereinafter also referred to as the "developing step").

[0171] According to the above-described resist pattern forming method, a high-quality resist pattern can be formed because the above-described radiation-sensitive resin composition is used, which is capable of forming a resist film that is excellent in sensitivity in the exposure step, LWR performance, CDU performance, pattern rectangularity, and etching resistance. Each step will be described below.

[0172] [Resist film formation process] In this step (step (1) above), a resist film is formed from the radiation-sensitive resin composition. Examples of substrates on which the resist film is formed include conventionally known substrates such as silicon wafers, silicon dioxide wafers, and aluminum-coated wafers. Alternatively, an organic or inorganic anti-reflective coating, such as those disclosed in Japanese Patent Publication No. 6-12452 or Japanese Patent Application Laid-Open No. 59-93448, may be formed on the substrate. Examples of coating methods include spin coating, casting coating, and roll coating. After coating, pre-baking (PB) may be performed, if necessary, to volatilize the solvent in the coating film. The PB temperature is typically 60°C to 140°C, and preferably 80°C to 120°C. The PB time is typically 5 seconds to 600 seconds, and preferably 10 seconds to 300 seconds. The thickness of the resist film formed is preferably 10 nm to 1,000 nm, and more preferably 10 nm to 500 nm.

[0173] When performing immersion exposure, regardless of whether the radiation-sensitive resin composition contains a water-repellent polymer additive such as a high-fluorine-content resin, a protective film for immersion exposure that is insoluble in the immersion liquid may be provided on the formed resist film to prevent direct contact between the immersion liquid and the resist film. The protective film for immersion exposure may be either a solvent-removable protective film that is removed with a solvent before the development step (see, for example, JP-A No. 2006-227632), or a developer-removable protective film that is removed simultaneously with development in the development step (see, for example, WO2005-069076 and WO2006-035790). However, from the viewpoint of throughput, it is preferable to use a developer-removable protective film for immersion exposure.

[0174] When the next exposure step is carried out using radiation with a wavelength of 50 nm or less, it is preferable to use a resin having the structural units (I) and (IV) as the base resin in the composition.

[0175] [Exposure process] In this step (step (2) above), the resist film formed in step (1), the resist film formation step, is exposed to radiation through a photomask (or, in some cases, through an immersion medium such as water). The radiation used for exposure may be, depending on the line width of the desired pattern, electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, EUV (extreme ultraviolet), X-rays, and gamma rays; or charged particle beams such as electron beams and alpha rays. Among these, far ultraviolet light, electron beams, and EUV are preferred, with ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), electron beams, and EUV being more preferred, and electron beams and EUV with wavelengths of 50 nm or less, which are positioned as next-generation exposure technologies, being even more preferred.

[0176] When exposure is performed by immersion exposure, examples of the immersion liquid used include water and fluorine-based inert liquids. The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has as small a temperature coefficient of refractive index as possible so as to minimize distortion of the optical image projected onto the film. However, particularly when the exposure light source is an ArF excimer laser (wavelength 193 nm), water is preferred for its availability and ease of handling, in addition to the above considerations. When water is used, a small proportion of an additive that reduces the surface tension of water and increases its surfactant power 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.

[0177] After the exposure, post-exposure baking (PEB) is preferably performed to promote dissociation of acid-dissociable groups in the resin or the like in the exposed portions of the resist film by the acid generated from the radiation-sensitive acid generator upon exposure. This PEB results in a difference in solubility in a developer between the exposed and unexposed portions. The PEB temperature is usually 50°C to 180°C, preferably 80°C to 130°C. The PEB time is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds.

[0178] [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, the resist film is generally washed with a rinse liquid such as water or alcohol, and then dried.

[0179] In the case of alkaline development, the developer used for the development may be, for example, 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, a TMAH aqueous solution is preferred, and a 2.38 mass % TMAH aqueous solution is more preferred.

[0180] In the case of organic solvent development, examples of the organic solvent include hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, and alcohol solvents, as well as solvents containing an organic solvent. Examples of the organic solvent 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 ether solvents, glycol ether solvents are preferred, with ethylene glycol monomethyl ether and propylene glycol monomethyl ether being more preferred. As ester solvents, acetate ester solvents are preferred, with n-butyl acetate and amyl acetate being more preferred. As ketone solvents, chain ketones are preferred, with 2-heptanone being more preferred. The content of the organic solvent 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 the organic solvent in the developer include water and silicone oil.

[0181] As mentioned above, the developer may be either an alkaline developer or an organic solvent developer, and can be appropriately selected depending on whether the desired pattern is a positive or negative pattern.

[0182] Examples of development methods include a method in which a substrate is immersed in a tank filled with developer for a certain period of time (dip method), a method in which developer is piled up on the surface of the substrate by surface tension and left to stand for a certain period of time (puddle method), a method in which developer is sprayed onto the surface of the substrate (spray method), and a method in which developer is continuously dispensed by scanning a developer dispensing nozzle at a constant speed over a substrate that is rotating at a constant speed (dynamic dispense method). [Example]

[0183] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Measurement methods for various physical properties are shown below.

[0184] [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, and the dispersity (Mw / Mn) was calculated from the measurement results of Mw and Mn.

[0185] [ 13 C-NMR analysis] polymer 13 C-NMR analysis was carried out using a nuclear magnetic resonance spectrometer (JNM-Delta400 manufactured by JEOL Ltd.).

[0186] <Synthesis of resin and high fluorine content resin> 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 refer to a value when the total mass of the monomers used is taken as 100 parts by mass, and mol % refers to a value when the total number of moles of the monomers used is taken as 100 mol %.

[0187] [ka]

[0188] [Synthesis Example 1] (Synthesis of Resin (A-1)) Monomer (M-1), monomer (M-2), and monomer (M-13) were dissolved in 2-butanone (200 parts by mass) to a molar ratio of 40 / 15 / 45 (mol%), and AIBN (azobisisobutyronitrile) (3 mol% relative to the total of 100 mol% of the monomers used) was added as an initiator to prepare a monomer solution. 2-butanone (100 parts by mass) 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 with stirring. The start of the dropwise addition marked the start of the polymerization reaction, which was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution was cooled to below 30°C using water. The cooled polymerization solution was poured into methanol (2,000 parts by mass), and the precipitated white powder was filtered off. The filtered white powder was washed twice with methanol, filtered, and dried at 50°C for 24 hours to obtain a white powdery resin (A-1) (yield: 83%). The Mw of the resin (A-1) was 8,800, and the Mw / Mn was 1.50. 13 As a result of C-NMR analysis, the contents of the structural units derived from (M-1), (M-2) and (M-13) were 41.3 mol %, 13.8 mol % and 44.9 mol %, respectively.

[0189] [Synthesis Examples 2 to 11] (Synthesis of Resin (A-2) to Resin (A-11)) Resins (A-2) to (A-11) were synthesized in the same manner as in Synthesis Example 1, except that the types and blending ratios of monomers shown in Table 1 below were used. The content (mol %) of each structural unit, the yield (%), and physical properties (Mw and Mw / Mn) of the resulting resins are also shown in Table 1 below. In Table 1 below, "-" indicates that the corresponding monomer was not used (the same applies to the following tables).

[0190] [Table 1]

[0191] [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) at a molar ratio of 50 / 50 (mol%), and AIBN (5 mol%) was added as an initiator to prepare a monomer solution. 1-Methoxy-2-propanol (100 parts by mass) 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 with stirring. The start of the dropwise addition marked the start of the polymerization reaction, which was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution was cooled to below 30°C with water. The cooled polymerization solution was poured into hexane (2,000 parts by mass), and the precipitated white powder was filtered off. The filtered white powder was washed twice with hexane, filtered off, and dissolved in 1-methoxy-2-propanol (300 parts by mass). Next, methanol (500 parts by mass), triethylamine (50 parts by mass), and ultrapure water (10 parts by mass) were added, and the mixture was stirred at 70°C for 6 hours to carry out a hydrolysis reaction. After the reaction was completed, the remaining solvent was distilled off, and the resulting solid was dissolved in acetone (100 parts by mass) and added dropwise to water (500 parts by mass) to coagulate the resin. The resulting solid was filtered and dried at 50°C for 13 hours to obtain white powdery resin (A-12) (yield: 79%). The Mw of resin (A-12) was 5,200, and the Mw / Mn ratio was 1.60. Furthermore, 13C-NMR analysis revealed that the content ratios of structural units derived from (M-1) and (M-18) were 51.3 mol% and 48.7 mol%, respectively.

[0192] [Synthesis Examples 13 to 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 types and blending ratios of monomers shown in Table 2 were used. The content (mol %) of each structural unit, the yield (%), and the physical properties (Mw and Mw / Mn) of the resulting resins are also shown in Table 2.

[0193] [Table 2]

[0194] [Synthesis Example 16] (Synthesis of high fluorine content resin (E-1)) Monomer (M-1) and monomer (M-20) were dissolved in 2-butanone (200 parts by mass) at a molar ratio of 20 / 80 (mol%), and AIBN (4 mol%) was added as an initiator to prepare a monomer solution. 2-butanone (100 parts by mass) was added to 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 with stirring. The polymerization reaction was initiated at the start of the dropwise addition and continued for 6 hours. After completion of the polymerization reaction, the polymerized solution was cooled to below 30°C with water. The solvent was replaced with acetonitrile (400 parts by mass), and then hexane (100 parts by mass) was added, stirred, and the acetonitrile layer was collected. This process was repeated three times. The solvent was replaced with propylene glycol monomethyl ether acetate to obtain a solution of high-fluorine-content resin (E-1) (yield: 69%). The high fluorine content resin (E-1) had an Mw of 6,000 and an Mw / Mn ratio of 1.62. 13 As a result of C-NMR analysis, the content ratios of the structural units derived from (M-1) and (M-20) were 19.9 mol % and 80.1 mol %, respectively.

[0195] [Synthesis Examples 17-20] (Synthesis of High Fluorine Content Resin (E-2) to High Fluorine Content Resin (E-5)) High fluorine content resins (E-2) to (E-5) were synthesized in the same manner as in Synthesis Example 16, except for using monomers of the types and blending ratios shown in Table 3 below. The content (mol %) of each structural unit, yield (%) and physical properties (Mw and Mw / Mn) of the obtained high fluorine content resins are also shown in Table 3 below.

[0196] [Table 3]

[0197] <Synthesis of Radiation-Sensitive Acid Generator (Onium Salt Compound) B> [Synthesis Example 21] (Synthesis of Compound (B-1)) Compound (B-1) was synthesized according to the following synthesis scheme.

[0198] [ka]

[0199] 20.0 mmol of 5-hydroxy-2-adamantanone, 30.0 mmol of trifluoroacetic acid, 30.0 mmol of dicyclohexylcarbodiimide, and 50 g of methylene chloride were added to a reaction vessel and stirred at room temperature for 4 hours. After dilution with water, methylene chloride was added for extraction, and the organic layer was separated. The resulting organic layer was washed with saturated aqueous sodium chloride and then with water. After drying over sodium sulfate, the solvent was distilled off, and the ester was purified by column chromatography to obtain it in good yield.

[0200] The ester was added with 30.0 mmol of methylmagnesium chloride, 30.0 mmol of lithium chloride, and 100 g of tetrahydrofuran, and the mixture was stirred at room temperature for 1 hour. The reaction was then terminated by adding saturated aqueous ammonium chloride, followed by extraction with ethyl acetate and separation of the organic layer. The resulting organic layer was washed with saturated aqueous sodium chloride and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the resulting mixture was purified by column chromatography to obtain the alcohol in good yield.

[0201] To the alcohol, 30.0 mmol of triethylamine, 30.0 mmol of bromodifluoroacetyl chloride, and 50 g of acetonitrile were added and stirred at 100°C for 6 hours. Subsequently, a saturated aqueous solution of ammonium chloride was added to terminate the reaction, followed by extraction with ethyl acetate and separation of the organic layer. The resulting organic layer was washed with a saturated aqueous solution of sodium chloride and then with water. After drying over sodium sulfate, the solvent was distilled off, and the mixture was purified by column chromatography to obtain the bromo-form in good yield.

[0202] A mixture of acetonitrile and water (1:1 (mass ratio)) was added to the above brominated product to prepare a 1 M solution, and then 40.0 mmol of sodium dithionite and 60.0 mmol of sodium bicarbonate were added and the mixture was allowed to react at 70°C for 4 hours. After extraction with acetonitrile and distillation of the solvent, a mixture of acetonitrile and water (3:1 (mass ratio)) was added to prepare a 0.5 M solution. 60.0 mmol of aqueous hydrogen peroxide and 2.00 mmol of sodium tungstate were added, and the mixture was heated and stirred at 50°C for 12 hours. Extraction with acetonitrile and distillation of the solvent yielded a sodium sulfonate salt compound. 20.0 mmol of triphenylsulfonium bromide was added to the above sodium sulfonate salt compound, and a mixture of water and dichloromethane (1:3 (mass ratio)) was added to prepare a 0.5 M solution. After vigorously stirring at room temperature for 3 hours, dichloromethane was added for extraction, and the organic layer was separated. The obtained organic layer was dried over sodium sulfate, the solvent was distilled off, and the residue was purified by column chromatography to obtain the compound (B-1) represented by the above formula (B-1) in good yield.

[0203] [Synthesis Examples 22 to 24] (Synthesis of Compounds (B-2) to (B-4)) Onium salts represented by the following formulae (B-2) to (B-4) were synthesized in the same manner as in Synthesis Example 21, except that the raw materials and precursors were changed as appropriate.

[0204] [ka]

[0205] [Synthesis Example 25] (Synthesis of Compound (B-5-1)) Compound (B-5-1) was synthesized according to the following synthesis scheme.

[0206] [ka]

[0207] A 1M solution was prepared by adding a mixture of acetonitrile and water (1:1 (mass ratio)) to 20.0 mmol of ethyl bromodifluoroacetate, followed by the addition of 40.0 mmol of sodium dithionite and 60.0 mmol of sodium bicarbonate, and the mixture was allowed to react at 70°C for 4 hours. After extraction with acetonitrile and the solvent was distilled off, a 0.5M solution was prepared by adding a mixture of acetonitrile and water (3:1 (mass ratio)). 60.0 mmol of aqueous hydrogen peroxide and 2.00 mmol of sodium tungstate were added, and the mixture was heated and stirred at 50°C for 12 hours. Extraction with acetonitrile and the solvent was distilled off yielded a sodium sulfonate salt compound. 20.0 mmol of triphenylsulfonium bromide was added to the sodium sulfonate salt compound, and a 0.5M solution was prepared by adding a mixture of water and dichloromethane (1:3 (mass ratio)). After vigorously stirring for 3 hours at room temperature, dichloromethane was added for extraction, and the organic layer was separated. The resulting organic layer was dried over sodium sulfate, the solvent was distilled off, and the residue was purified by column chromatography to obtain an onium salt in good yield.

[0208] A mixture of methanol and water (1:1 (mass ratio)) was added to the onium salt to prepare a 1M solution, and then 20.0 mmol of lithium hydroxide was added and reacted at room temperature for 2 hours. 2M hydrochloric acid was then added to terminate the reaction, followed by extraction with methylene chloride and separation of the organic layer. The resulting organic layer was dried over sodium sulfate, the solvent was distilled off, and the residue was purified by column chromatography to obtain compound (B-5-1) represented by formula (B-5-1) in good yield.

[0209] [Synthesis Example 26] (Synthesis of Compound (B-5)) Compound (B-5) was synthesized according to the following synthesis scheme.

[0210] [ka]

[0211] 20.0 mmol of 5-hydroxy-2-adamantanone, 30.0 mmol of methoxymethyl chloride, 30.0 mmol of triethylamine, and 50 g of tetrahydrofuran were added to a reaction vessel and stirred at room temperature for 4 hours. After dilution with water, methylene chloride was added for extraction, and the organic layer was separated. The resulting organic layer was washed with saturated aqueous sodium chloride and then with water. After drying with sodium sulfate, the solvent was removed by distillation, and the mixture was purified by column chromatography to obtain compound (B-5-2) represented by formula (B-5-2) in good yield.

[0212] To the compound (B-5-2), 30.0 mmol of ethyl magnesium chloride and 100 g of tetrahydrofuran were added and stirred at room temperature for 5 hours. The reaction was then stopped by adding saturated aqueous ammonium chloride, followed by extraction with ethyl acetate and separation of the organic layer. The resulting organic layer was washed with saturated aqueous sodium chloride and then with water. After drying with sodium sulfate, the solvent was removed by distillation, and the resulting mixture was purified by column chromatography to obtain the alcohol in good yield.

[0213] The alcohol was added with 30.0 mmol of triethylamine, 30.0 mmol of chloroacetyl chloride, and 50 g of acetonitrile, and the mixture was stirred at room temperature for 3 hours. The reaction was then stopped by adding saturated aqueous ammonium chloride solution, followed by extraction with ethyl acetate and separation of the organic layer. The resulting organic layer was washed with saturated aqueous sodium chloride solution and then with water. After drying with sodium sulfate, the solvent was removed by distillation, and the residue was purified by column chromatography to obtain compound (B-5-3) represented by formula (B-5-3) in good yield.

[0214] To the compound (B-5-3), 30.0 mmol of potassium carbonate, 20.0 mmol of compound (B-5-1), and 50 g of acetone were added, followed by stirring at 40°C for 24 hours. The reaction was then stopped by adding saturated aqueous ammonium chloride, followed by extraction with methylene chloride and separation of the organic layer. The resulting organic layer was washed with saturated aqueous sodium chloride and then with water. After drying with sodium sulfate, the solvent was removed by distillation, and the residue was purified by column chromatography to obtain compound (B-5) represented by formula (B-5) in good yield.

[0215] [Synthesis Examples 27-30] (Synthesis of Compounds (B-6) to (B-9)) Onium salts represented by the following formulae (B-6) to (B-9) were synthesized in the same manner as in Synthesis Example 26, except that the raw materials and precursors were changed as appropriate.

[0216] [ka]

[0217] [Synthesis Example 31] (Synthesis of Compound (B-10)) Compound (B-10) was synthesized according to the following synthesis scheme.

[0218] [ka]

[0219] A reaction vessel was charged with 20.0 mmol of cyclohexanone-4-carboxylic acid, 30.0 mmol of 7-hydroxyhexahydro-3,5-methanocyclopenta[c][1,2]oxathiol-1,1-dioxide, 30.0 mmol of dicyclohexylcarbodiimide, and 50 g of methylene chloride, and the mixture was stirred at room temperature for 10 hours. The mixture was then diluted with water, extracted with methylene chloride, and the organic layer was separated. The resulting organic layer was washed with saturated aqueous sodium chloride and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the ester was purified by column chromatography to obtain a good yield.

[0220] The ester was added with 30.0 mmol of methylmagnesium chloride, 30.0 mmol of lithium chloride, and 100 g of tetrahydrofuran, and the mixture was stirred at room temperature for 1 hour. The reaction was then terminated by adding saturated aqueous ammonium chloride, followed by extraction with ethyl acetate and separation of the organic layer. The resulting organic layer was washed with saturated aqueous sodium chloride and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the resulting mixture was purified by column chromatography to obtain the alcohol in good yield.

[0221] To the alcohol product, 30.0 mmol of triethylamine, 30.0 mmol of chloroacetyl chloride, and 50 g of acetonitrile were added and stirred at room temperature for 1 hour. The reaction was then terminated by adding saturated aqueous ammonium chloride, followed by extraction with ethyl acetate and separation of the organic layer. The resulting organic layer was washed with saturated aqueous sodium chloride and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the chloro product was obtained in good yield by purification by column chromatography.

[0222] To the above chloroform, 30.0 mmol of cesium carbonate, 20.0 mmol of compound (B-5-1), and 50 g of dimethylformamide were added and stirred at room temperature for 1 hour. Subsequently, a saturated aqueous solution of ammonium chloride was added to terminate the reaction, followed by extraction with methylene chloride and separation of the organic layer. The resulting organic layer was washed with a saturated aqueous solution of sodium chloride and then with water. After drying with sodium sulfate, the solvent was removed by distillation, and the residue was purified by column chromatography to obtain compound (B-10) represented by formula (B-10) in good yield.

[0223] [Synthesis Example 32] (Synthesis of Compound (B-11)) An onium salt represented by the following formula (B-11) was synthesized in the same manner as in Synthesis Example 31, except that the raw materials and precursors were changed appropriately.

[0224] [ka]

[0225] [Synthesis Example 33] (Synthesis of Compound (B-12)) Compound (B-12) was synthesized according to the following synthesis scheme.

[0226] [ka]

[0227] 20.0 mmol of bromodifluoroacetic acid, 20.0 mmol of 1,3-dihydroxyadamantane, 20.0 mmol of dicyclohexylcarbodiimide, and 50 g of methylene chloride were added to a reaction vessel and stirred at room temperature for 4 hours. After dilution with water, methylene chloride was added for extraction, and the organic layer was separated. The resulting organic layer was washed with saturated aqueous sodium chloride and then with water. After drying over sodium sulfate, the solvent was distilled off, and the ester was purified by column chromatography to obtain it in good yield.

[0228] A mixture of acetonitrile and water (1:1 (mass ratio)) was added to the above ester to prepare a 1 M solution, and then 40.0 mmol of sodium dithionite and 60.0 mmol of sodium bicarbonate were added and the mixture was allowed to react at 70°C for 5 hours. After extraction with acetonitrile and distillation of the solvent, a mixture of acetonitrile and water (3:1 (mass ratio)) was added to prepare a 0.5 M solution. 60.0 mmol of aqueous hydrogen peroxide and 2.00 mmol of sodium tungstate were added, and the mixture was heated and stirred at 50°C for 12 hours. A sodium sulfonate salt compound was obtained by extraction with acetonitrile and distillation of the solvent. 20.0 mmol of triphenylsulfonium bromide was added to the above sodium sulfonate salt compound, and a mixture of water and dichloromethane (1:3 (mass ratio)) was added to prepare a 0.5 M solution. After vigorously stirring at room temperature for 3 hours, dichloromethane was added for extraction, and the organic layer was separated. The resulting organic layer was dried over sodium sulfate, the solvent was distilled off, and the residue was purified by column chromatography to obtain an onium salt in good yield.

[0229] The onium salt was added with 30.0 mmol of sodium hydride, 30.0 mmol of compound (B-5-3), and 50 g of tetrahydrofuran, and the mixture was stirred at 50°C for 3 hours. The reaction was then stopped by adding saturated aqueous ammonium chloride solution, followed by extraction with methylene chloride and separation of the organic layer. The resulting organic layer was washed with saturated aqueous sodium chloride solution and then with water. After drying with sodium sulfate, the solvent was removed by distillation, and the residue was purified by column chromatography to obtain compound (B-12) represented by formula (B-12) in good yield.

[0230] [Synthesis Example 34] (Synthesis of compound (B-13)) An onium salt represented by the following formula (B-13) was synthesized in the same manner as in Synthesis Example 33, except that the raw materials and precursors were changed appropriately.

[0231] [ka]

[0232] [Synthesis Example 35] (Synthesis of compound (B-14)) Compound (B-14) was synthesized according to the following synthesis scheme.

[0233] [ka]

[0234] 20.0 mmol of (B-5-2), 30.0 mmol of methylmagnesium chloride, and 100 g of tetrahydrofuran were added to a reaction vessel and stirred at room temperature for 6 hours. Subsequently, a saturated aqueous solution of ammonium chloride was added to terminate the reaction, followed by extraction with ethyl acetate and separation of the organic layer. The resulting organic layer was washed with a saturated aqueous solution of sodium chloride and then with water. After drying with sodium sulfate, the solvent was removed by distillation, and the mixture was purified by column chromatography to obtain the compound (B-14-1) represented by the above formula (B-14-1) in good yield.

[0235] 20.0 mmol of 4-(bromomethyl)benzoic acid, 30.0 mmol of thionyl chloride, and 50 g of acetonitrile were added to a reaction vessel and stirred at room temperature for 1 hour. Then, 20.0 mmol of (B-14-1) and 30.0 mmol of triethylamine were added and stirred at room temperature for 6 hours. The reaction was then terminated by adding saturated aqueous ammonium chloride, followed by extraction with ethyl acetate and separation of the organic layer. The resulting organic layer was washed with saturated aqueous sodium chloride and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the bromoform was obtained in good yield by purification by column chromatography.

[0236] To the brominated product, 30.0 mmol of potassium carbonate, 20.0 mmol of compound (B-5-1), and 50 g of methyl ethyl ketone were added, and the mixture was stirred at 50°C for 5 hours. After that, a saturated aqueous solution of ammonium chloride was added to terminate the reaction, and methylene chloride was added for extraction, and the organic layer was separated. The resulting organic layer was washed with a saturated aqueous solution of sodium chloride and then with water. After drying with sodium sulfate, the solvent was distilled off, and the residue was purified by column chromatography to obtain compound (B-14) represented by formula (B-14) in good yield.

[0237] [Synthesis Example 36] (Synthesis of Compound (B-15-1)) Compound (B-15-1) was synthesized according to the following synthesis scheme.

[0238] [ka]

[0239] 20.0 mmol of (B-5-1), 40.0 mmol of lithium aluminum hydride, and 100 g of tetrahydrofuran were added to a reaction vessel and stirred at room temperature for 6 hours. Then, saturated aqueous potassium sodium tartrate solution was added to terminate the reaction, followed by extraction with methylene chloride and separation of the organic layer. The resulting organic layer was dried over sodium sulfate, the solvent was distilled off, and the mixture was recrystallized and purified to obtain the compound (B-15-1) represented by the above formula (B-15-1) in good yield.

[0240] [Synthesis Example 37] (Synthesis of compound (B-15)) Compound (B-15) was synthesized according to the following synthesis scheme.

[0241] [ka]

[0242] 20.0 mmol of (B-14-1), 30.0 mmol of triethylamine, 30.0 mmol of chloroacetyl chloride, and 50 g of acetonitrile were added to a reaction vessel and stirred at room temperature for 1 hour. The reaction was then terminated by adding saturated aqueous ammonium chloride, followed by extraction with ethyl acetate and separation of the organic layer. The resulting organic layer was washed with saturated aqueous sodium chloride and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the chloroform was obtained in good yield by purification by column chromatography.

[0243] To the above chloroform, 30.0 mmol of sodium hydride, 30.0 mmol of methyl 3-hydroxy-1-adamantanecarboxylate, and 50 g of tetrahydrofuran were added, and the mixture was stirred at 50°C for 3 hours. Subsequently, a saturated aqueous solution of ammonium chloride was added to terminate the reaction, followed by extraction with ethyl acetate and separation of the organic layer. The resulting organic layer was washed with a saturated aqueous solution of sodium chloride and then with water. After drying over sodium sulfate, the solvent was distilled off, and the ester was purified by column chromatography to obtain the ester in good yield.

[0244] A mixture of tetrahydrofuran and water (1:1 (mass ratio)) was added to the above ester to prepare a 1 M solution, and then 20.0 mmol of lithium hydroxide was added and reacted at room temperature for 2 hours. After that, 2 M hydrochloric acid was added to terminate the reaction, and then ethyl acetate was added for extraction and the organic layer was separated. The obtained organic layer was dried over sodium sulfate, and the solvent was distilled off. The carboxylic acid was then purified by column chromatography to obtain a carboxylic acid in good yield.

[0245] To the above carboxylic acid compound, 20.0 mmol of (B-15-1), 30.0 mmol of dicyclohexylcarbodiimide, and 50 g of methylene chloride were added, and the mixture was stirred at room temperature for 3 hours. After dilution with water, methylene chloride was added for extraction, and the organic layer was separated. The resulting organic layer was washed with a saturated aqueous sodium chloride solution and then with water. After drying with sodium sulfate, the solvent was distilled off, and the mixture was purified by column chromatography to obtain compound (B-15) represented by the above formula (B-15) in good yield.

[0246] [Synthesis Examples 38-40] (Synthesis of compounds (B-16) to (B-18)) Onium salts represented by the following formulae (B-16) to (B-18) were synthesized in the same manner as in Synthesis Example 37, except that the raw materials and precursors were changed as appropriate.

[0247] [ka]

[0248] [Synthesis Example 41] (Synthesis of compound (B-19)) Compound (B-19) was synthesized according to the following synthesis scheme.

[0249] [ka]

[0250] 20.0 mmol of 5-hydroxy-2-adamantanone, 30.0 mmol of methyl vinyl ether, 20.0 mmol of tosylic acid monohydrate, and 50 g of tetrahydrofuran were added to a reaction vessel and stirred at room temperature for 10 hours. After dilution with water, ethyl acetate was added for extraction, and the organic layer was separated. The resulting organic layer was washed with saturated aqueous sodium chloride and then with water. After drying over sodium sulfate, the solvent was distilled off, and the residue was purified by column chromatography to obtain the acetal product in good yield.

[0251] To the above acetal product, 30.0 mmol of methylmagnesium chloride and 100 g of tetrahydrofuran were added and stirred at room temperature for 4 hours. Subsequently, a saturated aqueous solution of ammonium chloride was added to terminate the reaction, followed by extraction with ethyl acetate and separation of the organic layer. The resulting organic layer was washed with a saturated aqueous solution of sodium chloride and then with water. After drying over sodium sulfate, the solvent was distilled off and the mixture was purified by column chromatography to obtain the alcohol product in good yield.

[0252] 20.0 mmol of monomethyl terephthalate, 30.0 mmol of thionyl chloride, and 50 g of acetonitrile were added to a reaction vessel and stirred at room temperature for 1 hour. Then, 20.0 mmol of the above alcohol and 30.0 mmol of triethylamine were added and stirred at room temperature for 10 hours. The reaction was then terminated by adding saturated aqueous ammonium chloride, followed by extraction with ethyl acetate and separation of the organic layer. The resulting organic layer was washed with saturated aqueous sodium chloride and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the ester was purified by column chromatography to obtain it in good yield.

[0253] A mixture of tetrahydrofuran and water (1:1 (mass ratio)) was added to the above ester to prepare a 1 M solution, and then 20.0 mmol of lithium hydroxide was added and reacted at room temperature for 3 hours. After that, 2 M hydrochloric acid was added to terminate the reaction, and then ethyl acetate was added for extraction and the organic layer was separated. The obtained organic layer was dried over sodium sulfate, and the solvent was distilled off. The carboxylic acid was then purified by column chromatography to obtain a carboxylic acid in good yield.

[0254] To the above carboxylic acid compound, 20.0 mmol of (B-15-1), 30.0 mmol of dicyclohexylcarbodiimide, and 50 g of methylene chloride were added, and the mixture was stirred at room temperature for 3 hours. After dilution with water, methylene chloride was added for extraction, and the organic layer was separated. The resulting organic layer was washed with a saturated aqueous sodium chloride solution and then with water. After drying with sodium sulfate, the solvent was distilled off, and the residue was purified by column chromatography to obtain compound (B-19) represented by formula (B-19) in good yield.

[0255] [Synthesis Example 42] (Synthesis of compound (B-20)) Compound (B-20) was synthesized according to the following synthesis scheme.

[0256] [ka]

[0257] 20.0 mmol of (B-5), 40.0 mmol of 2M hydrochloric acid, and 50 g of methanol were added to a reaction vessel and stirred at room temperature for 10 hours. After dilution with water, methylene chloride was added for extraction, and the organic layer was separated. The resulting organic layer was dried over sodium sulfate, the solvent was removed by distillation, and the mixture was purified by column chromatography to obtain compound (B-20) represented by the above formula (B-20) in good yield.

[0258] [Synthesis Examples 43-44] (Synthesis of Compounds (B-21) to (B-22)) Onium salts represented by the following formulae (B-21) and (B-22) were synthesized in the same manner as in Synthesis Example 42, except that the raw materials and precursors were changed as appropriate.

[0259] [ka]

[0260] [Physical properties of compounds (B-1) to (B-22)] The van der Waals volume change rate and the difference in CLogP value between the anion structures of the compounds (B-1) to (B-22) and the structures after cleavage of the acid-dissociable groups of the anion structures are shown in Table 4. The methods for calculating each physical property are as follows.

[0261] (Van der Waals volume change rate) The van der Waals volumes of each compound were calculated using RDKit, an open-source chemoinformatics software, and the rate of change was calculated according to the above formula (i).

[0262] (difference in ClogP values) Each ClogP value was calculated using Chemdraw (CambridgeSoft, Ver. 12), and the difference was calculated according to the above formula (ii).

[0263] [Table 4]

[0264] [Onium salt compounds other than compounds (B-1) to (B-22)] b-1 to b-16: Compounds represented by the following formulas (b-1) to (b-16) (hereinafter, the compounds represented by formulas (b-1) to (b-16) may be referred to as "compound (b-1)" to "compound (b-16)", respectively.) The rate of change in van der Waals volume and the change in CLogP value for compounds (b-1) to (b-16) are shown in Table 5. In Table 5, "-" indicates that the anion structure before exposure did not have an acid-dissociable group, and therefore a structure in which the acid-dissociable group was cleaved was not obtained.

[0265] [ka]

[0266] [Table 5]

[0267] [[C] Acid diffusion control agent] C-1 to C-8: Compounds represented by the following formulas (C-1) to (C-8) (hereinafter, the compounds represented by formulas (C-1) to (C-8) may be referred to as "compound (C-1)" to "compound (C-8)", respectively.)

[0268] [ka]

[0269] [[D] Solvent] D-1: Propylene Glycol Monomethyl Ether Acetate D-2: Propylene Glycol Monomethyl Ether D-3: γ-Butyrolactone D-4: Ethyl Lactate

[0270] [Preparation of Positive-Type Radiation-Sensitive Resin Composition for ArF Exposure] [Example 1] [(A-1) 100 parts by mass as resin, (B-1) 12.0 parts by mass as radiation-sensitive acid generator, (C-1) 5.0 parts by mass as acid diffusion controller, (E-1) 3.0 parts by mass (solid content) as high fluorine content resin, and 3,230 parts by mass of mixed solvent of (D-1) / (D-2) / (D-3) as [D] 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-1).]

[0271] [Examples 2 to 48 and Comparative Examples 1 to 19] [Except for using each component of the types and contents shown in Table 6 below, in the same manner as in Example 1, radiation-sensitive resin compositions (J-2) to (J-48) and (CJ-1) to (CJ-19) were prepared.]

[0272] [Table 6]

[0273] [Formation of Resist Pattern Using Positive-Type Radiation-Sensitive Resin Composition for ArF Exposure] A 12-inch silicon wafer was coated with a composition for forming a bottom anti-reflective coating (Brewer Science's ARC66) using a spin coater (Tokyo Electron Limited's CLEAN TRACK ACT12), followed by heating at 205°C for 60 seconds to form a bottom anti-reflective coating with an average thickness of 100 nm. The positive radiation-sensitive resin composition for ArF exposure prepared above was coated onto this bottom anti-reflective coating using the spin coater, followed by pre-baking at 100°C for 60 seconds. This was then cooled at 23°C for 30 seconds to form a resist film with an average thickness of 90 nm. This resist film was then exposed to light using an ArF excimer laser immersion exposure system (ASML's TWINSCAN XT-1900i) 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, PEB (post-exposure bake) was performed for 60 seconds at 100° C. Then, the resist film was alkaline-developed using a 2.38% by mass aqueous solution of TMAH as an alkaline developer, and after development, the resist film was washed with water and further dried to form a positive resist pattern (40 nm line and space pattern).

[0274] <Evaluation> The resist patterns formed using the positive radiation-sensitive resin composition for ArF exposure were evaluated for sensitivity, LWR performance, and pattern rectangularity according to the following methods. The results are shown in Table 7. The resist patterns were measured using a scanning electron microscope (CG-5000 manufactured by Hitachi High-Technologies Corporation).

[0275] [sensitivity] In forming a resist pattern using the positive radiation-sensitive resin composition for ArF exposure, the exposure dose for forming a 40 nm line and space pattern was defined as the optimum exposure dose, and this optimum exposure dose was determined as the sensitivity (mJ / cm 2 The sensitivity was 25 mJ / cm 2 The following are considered "good" and 25mJ / cm 2 If it exceeded this, it was rated as "poor".

[0276] [LWR performance] A 40 nm line-and-space resist pattern was formed by irradiating the resist with the optimal exposure dose determined in the sensitivity evaluation above. The formed resist pattern was observed from above using the scanning electron microscope described above. The line width variation was measured at a total of 500 points, and a 3 sigma value was calculated from the distribution of the measured values. This 3 sigma value was taken as the LWR (nm). The smaller the LWR value, the smaller the line roughness and the better the result. LWR performance was evaluated as "good" when it was 2.5 nm or less, and "poor" when it exceeded 2.5 nm.

[0277] Pattern Rectangularity A 40 nm line-and-space resist pattern formed by irradiating with the optimum exposure dose determined in the sensitivity evaluation was observed using the scanning electron microscope, and the cross-sectional shape of the line-and-space pattern was evaluated. The rectangularity of the resist pattern was evaluated as "A" (very good) if the ratio of the bottom side length to the top side length in the cross-sectional shape was 1 or more and 1.05 or less, "B" (good) if it was more than 1.05 and 1.10 or less, and "C" (poor) if it was more than 1.10.

[0278] [Table 7]

[0279] As is clear from the results in Table 7, the radiation-sensitive resin compositions of the Examples exhibited good sensitivity, LWR performance, and pattern rectangularity when used in ArF exposure, whereas the Comparative Examples were inferior in each property to the Examples. Therefore, when the radiation-sensitive resin compositions of the Examples are used in ArF exposure, resist patterns with high sensitivity, good LWR performance, and excellent rectangularity can be formed.

[0280] [Preparation of Positive-Working Radiation-Sensitive Resin Composition for Extreme Ultraviolet (EUV) Exposure] [Example 49] 100 parts by mass of (A-12) as a resin, 15.0 parts by mass of (B-6) as a radiation-sensitive acid generator, 8.0 parts by mass of (C-1) as an acid diffusion controller, 3.0 parts by mass (solid content) of (E-5) 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-49).

[0281] [Examples 50 to 61 and Comparative Examples 20 to 23] Except for using the components of the types and contents shown in Table 8 below, radiation-sensitive resin compositions (J-50) to (J-61) and (CJ-20) to (CJ-23) were prepared in the same manner as in Example 49.

[0282]

Table 8

[0283] <Formation of a resist pattern using a positive-type radiation-sensitive resin composition for EUV lithography> A 12-inch silicon wafer was coated with a composition for forming a bottom anti-reflective coating (Brewer Science's ARC66) using a spin coater (Tokyo Electron Limited's CLEAN TRACK ACT12), followed by heating at 205°C for 60 seconds to form a bottom anti-reflective coating with an average thickness of 105 nm. The positive radiation-sensitive resin composition for EUV exposure prepared above was coated onto this bottom anti-reflective coating using the spin coater, followed by post-baking at 130°C for 60 seconds. This was then cooled at 23°C for 30 seconds to form a resist film with an average thickness of 55 nm. This resist film was then exposed to light using an EUV exposure system (ASML's NXE3300) with NA=0.33, illumination conditions: Conventional s=0.89, and a mask: imecDEFECT32FFR02. After exposure, post-baking was performed at 120°C for 60 seconds. Thereafter, the resist film was subjected to alkaline development using a 2.38% by mass aqueous solution of TMAH as an alkaline developer, and after development, the resist film was washed with water and then dried to form a positive resist pattern (32 nm line and space pattern).

[0284] <Evaluation> The sensitivity and LWR performance of the resist patterns formed using the above-mentioned positive radiation-sensitive resin composition for EUV exposure were evaluated according to the following methods. The results are shown in Table 9. The resist patterns were measured using a scanning electron microscope ("CG-5000" manufactured by Hitachi High-Technologies Corporation).

[0285] [sensitivity] In forming a resist pattern using the positive-tone radiation-sensitive resin composition for EUV exposure, the exposure dose for forming a 32 nm line and space pattern was defined as the optimum exposure dose, and this optimum exposure dose was determined as the sensitivity (mJ / cm 2 The sensitivity was 25 mJ / cm 2 The following are considered "good" and 25mJ / cm 2 If it exceeded this, it was rated as "poor".

[0286] [LWR performance] A resist pattern was formed by irradiating the substrate with the optimal exposure dose determined in the sensitivity evaluation above, and adjusting the mask size to form a 32 nm line-and-space pattern. The formed resist pattern was observed from above using the scanning electron microscope described above. The line width variation was measured at a total of 500 points, and a 3 sigma value was calculated from the distribution of the measured values. This 3 sigma value was taken as the LWR (nm). The smaller the LWR value, the smaller the line wobble and the better the result. LWR performance was evaluated as "good" when it was 2.5 nm or less, and "poor" when it was greater than 2.5 nm.

[0287] [Table 9]

[0288] As is clear from the results in Table 9, the radiation-sensitive resin compositions of the Examples had good sensitivity and LWR performance when used for EUV exposure, whereas the Comparative Examples were inferior in each property to the Examples.

[0289] [Preparation of a negative-tone radiation-sensitive resin composition for ArF exposure, and formation and evaluation of a resist pattern using this composition] [Example 62] A radiation-sensitive resin composition (J-62) was prepared by mixing 100 parts by mass of (A-6) as the resin [A], 10.0 parts by mass of (B-15) as the radiation-sensitive acid generator [B], 6.0 parts by mass of (C-1) as the acid diffusion controller [C], 1.0 part by mass (solids content) of (E) as the high fluorine content resin [E-4], and 3,230 parts by mass of the mixed solvent of (D-1) / (D-2) / (D-3) as the solvent [D], and filtering the mixture through a membrane filter having a pore size of 0.2 μm.

[0290] A 12-inch silicon wafer was coated with a composition for forming a bottom anti-reflective coating (Brewer Science's ARC66) using a spin coater (Tokyo Electron Limited's CLEAN TRACK ACT12), followed by heating at 205°C for 60 seconds to form a bottom anti-reflective coating with an average thickness of 100 nm. The negative radiation-sensitive resin composition for ArF exposure (J-62) prepared above was then coated onto the bottom anti-reflective coating using the spin coater, followed by pre-baking at 100°C for 60 seconds. The wafer was then cooled at 23°C for 30 seconds to form a resist film with an average thickness of 90 nm. This resist film was then exposed to light using an ArF excimer laser immersion exposure system (ASML's TWINSCAN XT-1900i) 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 the exposure, PEB (post-exposure bake) was performed for 60 seconds at 100° C. Then, the resist film was developed using n-butyl acetate as an organic solvent developer and dried to form a negative resist pattern (40 nm holes, 105 nm pitch).

[0291] <Evaluation> The CDU performance of the resist patterns formed using the negative radiation-sensitive resin composition for ArF exposure was evaluated according to the following method. The resist pattern dimensions were measured using a scanning electron microscope (CG-5000, manufactured by Hitachi High-Technologies Corporation).

[0292] [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 above-mentioned scanning electron microscope. The dimensional variation (3σ) was calculated and used as the CDU performance (nm). The smaller the CDU value, the smaller the variation in hole diameter over a long period, indicating better performance.

[0293] The resist patterns formed using the negative-tone radiation-sensitive resin compositions for ArF exposure were evaluated as described above. As a result, the radiation-sensitive resin composition of Example 62 exhibited good CDU performance even when a negative-tone resist pattern was formed by ArF exposure.

[0294] [Preparation of a negative-tone radiation-sensitive resin composition for EUV exposure, and formation and evaluation of a resist pattern using this composition] [Example 63] A radiation-sensitive resin composition (J-63) was prepared by mixing 100 parts by mass of (A-13) as the resin [A], 18.0 parts by mass of (B-13) as the radiation-sensitive acid generator [B], 10.0 parts by mass of (C-1) as the acid diffusion controller [C], 1.0 part by mass (solids content) of (E-5) as the high fluorine-content resin [E], and 6,110 parts by mass of a mixed solvent of (D-1) / (D-4) as the solvent [D], and filtering the mixture through a membrane filter having a pore size of 0.2 μm.

[0295] A 12-inch silicon wafer was coated with a composition for forming a bottom anti-reflective coating (Brewer Science's ARC66) using a spin coater (Tokyo Electron Limited's CLEAN TRACK ACT12), followed by heating at 205°C for 60 seconds to form a bottom anti-reflective coating with an average thickness of 105 nm. The negative radiation-sensitive resin composition for EUV exposure (J-63) prepared above was then coated onto this bottom anti-reflective coating using the spin coater, followed by post-baking at 130°C for 60 seconds. This was then cooled at 23°C for 30 seconds to form a resist film with an average thickness of 55 nm. This resist film was then exposed to light using an EUV exposure system (ASML's NXE3300) with NA=0.33, illumination conditions: Conventional s=0.89, and a mask: imecDEFECT32FFR02. After exposure, post-baking was performed at 120°C for 60 seconds. Thereafter, the resist film was developed with n-butyl acetate as an organic solvent developer and dried to form a negative resist pattern (40 nm holes, 105 nm pitch).

[0296] The resist pattern formed using the negative-tone radiation-sensitive resin composition for EUV exposure was evaluated in the same manner as the resist pattern formed using the negative-tone radiation-sensitive resin composition for ArF exposure. As a result, the radiation-sensitive resin composition of Example 63 had good sensitivity and CDU performance, even when a negative-tone resist pattern was formed by EUV exposure. [Industrial Applicability]

[0297] The radiation-sensitive resin composition and the method for forming a resist pattern described above can form a resist pattern that has good sensitivity to exposure light and is excellent in LWR performance, CDU performance, and pattern rectangularity. Therefore, these compositions can be suitably used in the fabrication processes of semiconductor devices, which are expected to become increasingly miniaturized in the future.

Claims

1. an onium salt compound represented by the following formula (1) and satisfying the following conditions (i) and (ii); a resin including a structural unit having an acid-dissociable group; a photodegradable base; Solvent and A radiation-sensitive resin composition comprising: 【Chemistry 1】 (In the above formula (1), R １ is a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms. R ２ , R ３ and R ４ are each independently a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 10 carbon atoms, or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms. m is 1. A １ is a single bond. A ２ is a divalent chain hydrocarbon group having 1 to 10 carbon atoms or a divalent cyclic organic group having 5 to 10 ring members. L is -O-, -CO-, -COO-, -OCO-, -O-CO-O-, -S-, -SO ２ It is a divalent linking group selected from -, -CONH-, and -NHCO-. n is 1 or 2, and when n is 2, two Ls are the same or different from each other; ２ One of the groups is a divalent cyclic organic group having 5 to 10 ring members, and the other is a divalent chain hydrocarbon group having 1 to 10 carbon atoms. R ５ is an acid-dissociable group represented by the following formula (1-1) or (1-2). Z ＋ is a monovalent radiation-sensitive onium cation. 【Chemistry 2】 (In the above formula (1-1), R １Ａ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. １Ｂ and R １Ｃ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a divalent cyclic organic group having 5 to 10 ring members formed by combining these groups together with the carbon atoms to which they are bonded. * represents R in the above formula (1). ５ indicates the bonding site with the oxygen atom adjacent to In the above formula (1-2), Y is —O— or —S—. ２Ａ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R ２Ｂ is a monovalent hydrocarbon group having 1 to 20 carbon atoms, or R ２Ａ and R ２Ｂ represents a divalent cyclic organic group having 5 to 10 ring members, which is formed by combining together with the atomic chain to which they are bonded. * represents R ５ indicates the bonding site with the oxygen atom adjacent to Condition (i): In the anion structure of the onium salt compound represented by formula (1), the rate of change in van der Waals volume of the structure before and after cleavage of the acid-dissociable group represented by formula (i) below is 32% or more and 67% or less. (W1-W2) / (W1)×100(%) ...(i) (In the above formula (i), W1 represents the van der Waals volume of the anion structure of the onium salt compound represented by the above formula (1), and W2 represents the van der Waals volume of the structure after the acid-dissociable group of the anion structure has been cleaved by the acid generated by irradiation with actinic rays or radiation.) Condition (ii): The difference in ClogP value between the anion structure of the onium salt compound represented by formula (1) above and the structure represented by formula (ii) below before and after cleavage of the acid-dissociable group is 3.00 or less. (P1-P2) ...(ii) (In the above formula (ii), P1 represents the ClogP value of the anion structure of the onium salt compound represented by the above formula (1), and P2 represents the ClogP value of the structure after the acid-dissociable group of the anion structure has been cleaved by an acid generated by irradiation with actinic rays or radiation.)

2. The radiation-sensitive resin composition according to claim 1, wherein the photodegradable base is at least one selected from the group consisting of a sulfonium salt compound represented by the following formula (7-1) and an iodonium salt compound represented by the following formula (7-2): 【Transformation 3】 (In the above formula (7-1) and formula (7-2), J ＋ is a sulfonium cation, and U ＋ is an iodonium cation. － and Q － are each independently OH － , R α -COO － , or R α -SO ３ － It is an anion represented by R α is an alkyl group, an aryl group, or an aralkyl group. α A hydrogen atom on the aromatic ring of the aryl group or aralkyl group represented by the formula (I) may be substituted with a hydroxy group, a fluorine atom-substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.

3. R in the above formula (1) ３ and R ４ 3. The radiation-sensitive resin composition according to claim 1, wherein is a hydrogen atom.

4. R in the above formula (1) ５ The radiation-sensitive resin composition according to any one of claims 1 to 3, wherein is a group represented by the above formula (1-1).

5. 5. The radiation-sensitive resin composition according to claim 1, wherein the resin further has a structural unit containing at least one structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure.

6. 6. The radiation-sensitive resin composition according to claim 1, wherein the structural unit having an acid-dissociable group in the resin is represented by the following formula (2): 【Chemistry 4】 (In the formula, R ６ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ７ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ８ and R ９ are each independently a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R ８ and R ９ are combined together with the carbon atoms to which they are bonded to form a divalent alicyclic group having 3 to 20 carbon atoms.

7. a step of directly or indirectly applying the radiation-sensitive resin composition according to any one of claims 1 to 6 onto a substrate to form a resist film; exposing the resist film to light; developing the exposed resist film with a developer; A pattern forming method comprising:

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