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

Abstract

The radiation-sensitive composition contains a polymer containing a structural unit represented by formula (1). In formula (1), R1 represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. And X1 is a single bond, * 1-COO <->, * 1-CONH <->, or a divalent aromatic ring group. And W1 represents an (r + 2)-valent organic group. And X2 is * 3-COO <-> or-O <->. G1 represents an acid-dissociable group; and r is 1 or 2. And R2 and R3 independently represent a fluorine atom or a fluoroalkyl group. Ma < + > is an a-valent cation. # imgabs0 #

Description

Technical Field

[0001] [Cross-reference to related applications]

[0002] This application claims priority based on Japanese Patent Application No. 2023-42261, filed on March 16, 2023, the entire contents of which are incorporated herein by reference.

[0003] The present disclosure relates to a radiation-sensitive composition, a resist pattern forming method, a polymer, and a compound. Background Art

[0004] In photolithography, used in the manufacturing process of various electronic components such as semiconductor devices and liquid crystal devices, a radiation-sensitive composition is irradiated with far ultraviolet light (such as ArF excimer laser), extreme ultraviolet light (EUV), electron beams, etc., to generate acid in the exposed area. Through the chemical reaction involving this acid, a difference in the dissolution rate of the exposed and unexposed areas in the developer solution is generated, thereby forming a resist pattern on the substrate.

[0005] The miniaturization of various electronic component structures is rapidly advancing, and with this, there is a demand for further miniaturization of resist patterns in photolithography processes. Furthermore, with the demand for further miniaturization of resist patterns, various studies have been conducted to improve the resolution of radiation-sensitive compositions used in microfabrication by photolithography and the pattern shape of resist patterns (for example, see Patent Document 1). Patent Document 1 discloses that a radiation-sensitive composition contains a resin having repeating units that decompose upon irradiation with actinic rays or radiation to generate an acid.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-154216 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] In recent years, the miniaturization of resist patterns has been rapidly advancing, with attempts to form patterns with line widths of 40 nm or less. Radiation-sensitive compositions are required to produce resist patterns with low exposure doses (i.e., high sensitivity) and excellent lithographic properties, such as line width roughness (LWR), even when forming such fine resist patterns.

[0011] When exposing a radiation-sensitive composition, if acid generated in the exposed area diffuses into the unexposed area, the resolution of the resist film may be reduced, making it impossible to obtain a fine pattern. Furthermore, as resist patterns become increasingly miniaturized, slight differences in process conditions, such as exposure and development conditions, can affect the resist pattern's shape and cause defects. Therefore, radiation-sensitive compositions are required to have a margin to accommodate slight differences in process conditions. Specifically, a wide range of process conditions (hereinafter referred to as "process margin") is required to form a resist pattern without causing breakage or collapse.

[0012] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide a radiation-sensitive composition and a resist pattern forming method having high sensitivity, good LWR performance, and a sufficiently wide process margin during pattern formation.

[0013] Technical means to solve the problem

[0014] According to one aspect of the present disclosure, there is provided a radiation-sensitive composition comprising a polymer including a structural unit represented by the following formula (1).

[0015] [Chemistry 1]

[0016]

[0017] (In formula (1), R 1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; X 1 For single key, * 1 -COO-,* 1 -CONH-, or a divalent aromatic ring group; "* 1 " indicates that the 1 The bond of the carbon atom to which it is bonded; W 1 is an organic group with a valence of (r+2); X 2 for* 3 -COO- or -O-; "* 3 " indicates that 1 Bond of G 1 is an acid dissociative group; r is 1 or 2; when r is 2, the two G 1 Same or different; R 2 and R 3 are independently a fluorine atom or a fluoroalkyl group; M a+ is an a-valent cation; a is 1 or 2)

[0018] According to another aspect of the present disclosure, a resist pattern forming method is provided, comprising: forming a resist film on a substrate using the radiation-sensitive composition; exposing the resist film; and developing the exposed resist film.

[0019] According to another aspect of the present disclosure, a polymer is provided, comprising a structural unit represented by the above formula (1). In another aspect of the present disclosure, a compound is provided, represented by the following formula (2).

[0020] [Chemistry 2]

[0021]

[0022] (In formula (2), R 1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; X 1 For single key, * 1 -COO-,* 1 -CONH-, or a divalent aromatic ring group; "* 1 " indicates that the 1 The bond of the carbon atom to which it is bonded; W 1 is an organic group with a valence of (r+2); X 2 for* 3 -COO- or -O-; "* 3 " indicates that 1 Bond of G 1 is an acid dissociative group; r is 1 or 2; when r is 2, the two G 1 Same or different; R 2 and R 3 are independently a fluorine atom or a fluoroalkyl group; M a+ is an a-valent cation; a is 1 or 2)

[0023] Effects of the Invention

[0024] The radiation-sensitive composition of the present disclosure has high sensitivity, and thus can form a good resist pattern with a small exposure dose. Furthermore, the radiation-sensitive composition of the present disclosure has good LWR performance and can ensure a wide process margin during pattern formation. DETAILED DESCRIPTION

[0025] Radiation-sensitive composites

[0026] The radiation-sensitive composition disclosed herein (hereinafter also referred to as "the present composition") contains [A] a polymer. Furthermore, the present composition may contain, as optional components, one or more of [Z] an acid diffusion controller, [B] a radiation-sensitive acid generator (excluding the polymer [A]), [D] a solvent, and [F] a high-fluorine-content polymer. Each component is described in detail below.

[0027] In addition, in this specification, the term "hydrocarbon group" includes chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. "Chain hydrocarbon group" refers to a straight-chain hydrocarbon group and a branched hydrocarbon group that does not contain a cyclic structure but only a chain structure. The chain hydrocarbon group may be saturated or unsaturated. "Alicyclic hydrocarbon group" refers to a hydrocarbon group that only contains an alicyclic hydrocarbon structure as a ring structure and does not contain an aromatic ring structure. The alicyclic hydrocarbon group does not need to contain only an alicyclic hydrocarbon structure and also includes groups that have a chain structure in part. "Aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure. The aromatic hydrocarbon group does not need to contain only an aromatic ring structure and may also contain a chain structure or an alicyclic hydrocarbon structure in part. "Aromatic ring group" refers to an n-valent group formed by removing n (where n is an integer greater than 1) hydrogen atoms from the ring portion of a substituted or unsubstituted aromatic ring. "Organic group" refers to an atomic group formed by removing any hydrogen atom from a carbon-containing compound (i.e., an organic compound). "Aromatic ring" includes aromatic hydrocarbon rings and aromatic heterocycles.

[0028] The expression "substituted or unsubstituted p-valent hydrocarbon group (wherein p is an integer greater than or equal to 1)" includes p-valent hydrocarbon groups (i.e., unsubstituted p-valent hydrocarbon groups) and groups formed by removing p hydrogen atoms from the hydrocarbon structure portion of a hydrocarbon group having a substituent. When an example of a substituted or unsubstituted p-valent hydrocarbon group is given, for example, an alkyl group or a fluoroalkyl group corresponds to the case where p=1, and an alkanediyl group or a fluoroalkanediyl group corresponds to the case where p=2. Among these, a fluoroalkyl group corresponds to a "substituted monovalent hydrocarbon group", and a fluoroalkanediyl group corresponds to a "substituted divalent hydrocarbon group". The same applies to other groups marked with "substituted or unsubstituted". "(Meth)acrylate" is a term that includes "acrylate" and "methacrylate".

[0029] <[A] Polymer>

[0030] The polymer [A] is a polymer containing a structural unit represented by the following formula (1) (hereinafter also referred to as a "first structural unit").

[0031] [Chemistry 3]

[0032]

[0033] (In formula (1), R 1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; X1 For single key, * 1 -COO-,* 1 -CONH-, or a divalent aromatic ring group; "* 1 " indicates that the 1 The bond of the carbon atom to which it is bonded; W 1 is an organic group with a valence of (r+2); X 2 for* 3 -COO- or -O-; "* 3 " indicates that 1 Bond of G 1 is an acid dissociative group; r is 1 or 2; when r is 2, the two G 1 Same or different; R 2 and R 3 are independently a fluorine atom or a fluoroalkyl group; M a+ is an a-valent cation; a is 1 or 2)

[0034] (First structural unit)

[0035] In the formula (1), from the viewpoint of copolymerizability of the monomer providing the first structural unit, R 1 Preferred is a hydrogen atom or a methyl group.

[0036] As X 1 The divalent aromatic ring group represented by can be a group formed by removing two hydrogen atoms from a substituted or unsubstituted aromatic ring. The aromatic ring can be a monocyclic ring or a condensed ring. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring. From the perspective of ease of synthesis of the monomer providing the first structural unit, a benzene ring or a naphthalene ring is preferred, and a benzene ring is more preferred. In X 1 When the divalent aromatic ring group represented has a substituent, examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.). The number of substituents is not particularly limited, and is, for example, 0 to 4, preferably 0 to 2.

[0037] G 1 is a group that replaces the hydrogen atom possessed by the carboxyl group or the hydroxyl group and is a group that dissociates by the action of an acid. If an acid is generated in the exposed portion by exposure of the present composition, then G 1 The generated acid dissociates the polymer to generate carboxyl groups or hydroxyl groups. This increases the solubility of the polymer [A] in the developer, and it is thought that the contrast of the resist film formed from the present composition can be improved.

[0038] Regarding the “-X 2 -G 1"The base represented by X 2 In the case of -COO-, it is preferably an ester structure, and in X 2 In the case of -O-, it preferably has an ester structure or an acetal structure.

[0039] As G 1 Examples of the acid-dissociable group include groups represented by the following formula (G-1).

[0040] [Chemistry 4]

[0041]

[0042] (In formula (G-1), R 4 is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms; R 5 and R 6 are independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, or R 5 and R 6 Combined with R 5 and R 6 The carbon atoms bonded together form an alicyclic hydrocarbon structure with 3 to 20 carbon atoms; "*" indicates a bond)

[0043] In the formula (G-1), R 4 、R 5 or R 6 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.

[0044] Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl; alkenyl groups such as vinyl, propenyl, and butenyl; and alkynyl groups such as ethynyl, propynyl, and butynyl. 4 、R 5 or R 6 The monovalent chain hydrocarbon group having 1 to 20 carbon atoms represented is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms.

[0045] Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include: monovalent monocyclic alicyclic saturated hydrocarbon groups such as cyclopentyl, cyclohexyl, methylcyclopentyl, ethylcyclopentyl, methylcyclohexyl, and ethylcyclohexyl; monovalent monocyclic alicyclic unsaturated hydrocarbon groups such as cyclopentenyl, cyclohexenyl, methylcyclopentenyl, and methylcyclohexenyl; monovalent polycyclic alicyclic saturated hydrocarbon groups such as norbornyl, adamantyl, and tricyclodecanyl; and monovalent polycyclic alicyclic unsaturated hydrocarbon groups such as norbornyl, tricyclodecanyl, and dihydroindenyl.

[0046] Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include aryl groups such as phenyl, tolyl, xylyl, mesityl, naphthyl, methylnaphthyl, anthracenyl, methylanthracenyl, and indenyl; and aralkyl groups such as benzyl, phenethyl, naphthylmethyl, and anthracenylmethyl.

[0047] As R 5 and R 6 Combined with R 5 and R 6 Examples of the alicyclic hydrocarbon structure having 3 to 20 carbon atoms formed by the bonded carbon atoms include: monocyclic saturated alicyclic hydrocarbon structures such as cyclopropane structure, cyclobutane structure, cyclopentane structure, cyclohexane structure, cycloheptane structure, and cyclooctane structure; monocyclic unsaturated alicyclic hydrocarbon structures such as cyclopentene structure and cyclohexene structure; and polycyclic alicyclic hydrocarbon structures such as norbornane structure, adamantane structure, tricyclodecane structure, and tetracyclododecane structure.

[0048] In R 4 、R 5 or R 6 When the group represented by has a substituent, examples of the substituent include a halogen atom (fluorine atom, bromine atom, chlorine atom, iodine atom, etc.), a hydroxyl group, an alkoxy group having 1 to 3 carbon atoms, and the like. 5 and R 6 Combined with R 5 and R 6 When the bonded carbon atoms together constitute an alicyclic hydrocarbon structure having 3 to 20 carbon atoms, the substituents or alkyl groups exemplified above may be bonded to the ring.

[0049] As the first structural unit "-COO-G 1 Specific examples of the group represented by " include groups represented by the following formulas.

[0050] [Chemistry 5]

[0051]

[0052] (Where “*” represents a bond)

[0053] As the first structural unit "-OG 1 Specific examples of the group represented by " include groups represented by the following formulas.

[0054] [Chemistry 6]

[0055]

[0056] (Where “*” represents a bond)

[0057] In the formula (1), X2 In the case of -O-, as G 1 Examples of the acid-dissociable group include groups represented by the following formula (G-2) in addition to the groups represented by the above formula (G-1).

[0058] [Chemistry 7]

[0059]

[0060] (In formula (G-2), R 7 is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms; R 8 and R 9 In, R 8 is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, R 9 is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, or R 8 and R 9 Combined with R 8 The bonded carbon atom and R 9 The bonded oxygen atoms together form a ring; "*" indicates a bonding bond)

[0061] In the formula (G-2), R 7 、R 8 or R 9 The monovalent hydrocarbon group represented by can be, for example, a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, etc. Specific examples of these include the same R in the formula (G-1) as above. 4 、R 5 、R 6 The same groups as those exemplified in the description of . 7 、R 8 or R 9 When the group has a substituent, examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), a hydroxyl group, and an alkoxy group having 1 to 3 carbon atoms.

[0062] In the first structural unit "-OG 1 "In the base represented by G 1 Specific examples of the group represented by the formula (G-2) include groups represented by the following formulas.

[0063] [Chemistry 8]

[0064]

[0065] (Where “*” represents a bond)

[0066] As W 1 Examples of the (r+2)-valent organic group represented by include a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms, and a group having 1 to 30 carbon atoms in which the methylene group contained in the hydrocarbon group is substituted with a heteroatom-containing group (e.g., -O-, -S-, -CO-, -COO-, -NH-, -NHCO-, -SO2-) (hereinafter referred to as "group R B ”), base R B At least one of the hydrogen atoms possessed by the substituted group, etc. As the substituted hydrocarbon group and the substituted group R B Examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), a hydroxyl group, an aldehyde group, an acetyl group, and an ester group.

[0067] In W 1 In the (r+2)-valent organic group represented by 2 -G 1 " can be bonded to W 1 The chain structure in the 1 On the ring in "-X 2 -G 1 When the group represented by " is bonded to a chain structure, W 1 It is preferred to have a carbon atom bonded to the chain structure "-X 2 -G 1 " is a partial structure of a group represented by ". On the carbon atom contained in the chain structure is bonded "-X 2 -G 1 "In the case of a base represented by "-X 2 -G 1 The group represented by " may replace a hydrogen atom possessed by an alkanediyl group having 1 or more carbon atoms, or may replace a hydrogen atom possessed by an alkyl group having 1 or more carbon atoms.

[0068] In "-X 2 -G 1 The base bond represented by " is in W 1 In the case of the loop, as "-X 2 -G 1 Examples of the ring to which the group represented by " is bonded include aliphatic hydrocarbon rings having 3 to 20 carbon atoms, aliphatic heterocycles having 3 to 20 carbon atoms, aromatic hydrocarbon rings having 6 to 20 carbon atoms, and aromatic heterocycles having 5 to 20 carbon atoms. These rings may have substituents. Examples of the substituents include alkoxy groups, alkoxycarbonyl groups, halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.), hydroxyl groups, and cyano groups.

[0069] The aliphatic hydrocarbon ring having 3 to 20 carbon atoms may be monocyclic or polycyclic, and may be a saturated hydrocarbon ring or an unsaturated hydrocarbon ring. Examples of saturated hydrocarbon rings in the monocyclic aliphatic hydrocarbon ring include cyclopentane ring, cyclohexane ring, cycloheptane ring, and cyclooctane ring. Examples of unsaturated hydrocarbon rings in the monocyclic aliphatic hydrocarbon ring include cyclopentene ring, cyclohexene ring, cycloheptene ring, cyclooctene ring, and cyclodecene ring. The polycyclic aliphatic hydrocarbon ring may be any of a bridged alicyclic hydrocarbon structure and a condensed alicyclic hydrocarbon structure. The polycyclic aliphatic hydrocarbon ring is preferably a bridged alicyclic saturated hydrocarbon ring, preferably having a bicyclo[2.2.1]heptane structure, a bicyclo[2.2.2]octane structure, or a tricyclo[3.3.1.1 3,7 ]Decane structure.

[0070] Examples of the aliphatic heterocyclic ring having 3 to 20 carbon atoms include a ring having a cyclic ether structure, a cyclic acetal structure, a lactone structure, a cyclic carbonate structure, a sultone structure, or a thioxane structure. The aliphatic heterocyclic ring may be monocyclic or polycyclic, and may have a bridged ring structure, a condensed ring structure, or a spiro ring structure. Furthermore, the aliphatic heterocyclic ring may be a combination of two or more of the bridged ring structure, the condensed ring structure, and the spiro ring structure.

[0071] Examples of the aromatic hydrocarbon ring having 6 to 20 carbon atoms include a benzene ring, a naphthalene ring, an anthracene ring, an indene ring, and a fluorene ring. Examples of the aromatic heterocyclic ring having 5 to 20 carbon atoms include a furan ring and a thiophene ring.

[0072] From the viewpoint of improving the hydrophobicity of the resist film obtained from the present composition and increasing the difference in solubility between the exposed portion and the unexposed portion in the developer, W 1 It preferably contains a cyclic structure, more preferably contains at least one ring selected from the group consisting of an aromatic hydrocarbon ring, an aliphatic hydrocarbon ring and an aliphatic heterocycle and is bonded to the ring. 2 -G 1 " or a partial structure of a group represented by ", or a chain structure with "-X 2 -G 1 " and has at least one ring selected from the group consisting of an aromatic ring, an aliphatic hydrocarbon ring and an aliphatic heterocycle. 1 It has a chain structure with "-X 2 -G 1 In the case of a partial structure of a group represented by ", as W 1 The rings possessed can be listed as "-X 2 -G 1 When the group represented by " is bonded to a ring, it is the same ring as the ring exemplified in the specific example.

[0073] From the viewpoint of ease of synthesis, r is preferably 1.

[0074] In the formula (1), as "-X 2 -G 1 "The base represented by W 1 The divalent group formed by the bond is the following formula

[0075] [Chemistry 9]

[0076]

[0077] Specific examples of the divalent group represented by ("*" represents a bonding bond) include groups represented by the following formula (w-1).

[0078] [Chemistry 10]

[0079]

[0080] (In formula (w-1), R 20 is a single bond or a divalent linking group; R 21 is a divalent group represented by the following formula (r3-1) or formula (r3-2); R 22 is a divalent linking group; R 26 and R 27 are independently a hydrogen atom, a fluorine atom, an alkyl group having 1 to 3 carbon atoms, or a fluoroalkyl group having 1 to 3 carbon atoms; m is 0 or 1; "*" represents SO3 - Side bond key; "* 2 " indicates X 1 side bond)

[0081] [Chemistry 11]

[0082]

[0083] (In formula (r3-1) and formula (r3-2), R 23 is a trivalent aromatic hydrocarbon ring group, a trivalent aliphatic hydrocarbon ring group or a trivalent aliphatic heterocyclic group; R 24 is a single bond or an alkanediyl group having 1 to 3 carbon atoms; R 25 is a hydrogen atom or an alkyl group with 1 to 3 carbon atoms; X 2 for* 4 -COO- or -O-; "* 4 " indicates that the 24 Bond of G 1 (acid-dissociable group; "*" indicates a bonding bond)

[0084] In the formula (w-1), R 20 or R 22 The divalent linking group represented by can be exemplified as W 1Among the (r+2)-valent organic groups exemplified by the group, there are groups having 1 to 20 carbon atoms, -COO-, -O-, etc. From the viewpoint of sensitivity, R 20 It is preferred that there be no fluorine atom. 21 When it is a group represented by the formula (r3-2), R 22 It preferably has at least one ring selected from the group consisting of an aromatic ring, an aliphatic ring, and a heterocyclic ring.

[0085] In the above formula (r3-1) and formula (r3-2), R 23 Specific examples of the ring possessed by the trivalent aromatic hydrocarbon ring group, aliphatic hydrocarbon ring group or aliphatic heterocyclic group represented by "-X 2 -G 1 The base bond represented by " is in W 1 The rings in the embodiment are the same as those exemplified in the description of the rings in the embodiment. 1 Specific examples of R include the groups represented by the above formula (G-1). 24 Preferably it is a single bond or a methylene group. 25 Preferred is a hydrogen atom or a methyl group.

[0086] In the formula (1), R 2 or R 3 The fluoroalkyl group represented is preferably a group having 1 to 10 carbon atoms, and examples thereof include trifluoromethyl, 2,2,2-trifluoroethyl, perfluoroethyl, 2,2,3,3,3-pentafluoropropyl, 2,2,2-trifluoro-1-(trifluoromethyl)ethyl, perfluoro-n-propyl, perfluoroisopropyl, perfluoro-n-butyl, perfluoroisobutyl, perfluoro-t-butyl, 2,2,3,3,4,4,5,5-octafluoropentyl, and perfluorohexyl. Of these, a group having 1 to 5 carbon atoms is preferred, trifluoromethyl, 2,2,2-trifluoroethyl, or perfluoroethyl is more preferred, and trifluoromethyl is even more preferred.

[0087] From the perspective of sensitivity, R 2 and R 3 Preferred are a fluorine atom, a trifluoromethyl group, a 2,2,2-trifluoroethyl group, and a perfluoroethyl group, and more preferred are a fluorine atom or a trifluoromethyl group.

[0088] M a+ The cation represented by is preferably an organic cation. From the viewpoint of improving the photolithographic properties of the present composition, M a+ Preferred is a sulfonium cation, an iodonium cation or an ammonium cation, and more preferred is a sulfonium cation or an iodonium cation.

[0089] When a in the formula (1) is 1, as M a+Specific examples include cations represented by the following formula (7), cations represented by the following formula (8), and cations represented by the following formula (9).

[0090] [Chemistry 12]

[0091]

[0092] (In formula (7), R 1a and R 2a are independently monovalent substituents, or represent R 1a and R 2a A single bond or a divalent group that binds to each other and connects these bonded rings; R 3a is a monovalent substituent; a1 and a2 are independently an integer from 0 to 5; a3 is an integer from 0 to (2×r+5); r is 0 or 1;

[0093] In formula (8), R 4a and R 5a are independently monovalent substituents; a4 and a5 are independently integers of 0 to 5;

[0094] In formula (9), a6 is an integer from 0 to 7; when a6 is 1, R 6a is a monovalent organic group with 1 to 20 carbon atoms, a hydroxyl group, a nitro group or a halogen group; when a6 is 2 or more, multiple R 6a are the same or different and are monovalent organic groups with 1 to 20 carbon atoms, hydroxyl groups, nitro groups or halogen groups, or represent multiple R 6a Two of the carbon atoms are combined with each other and together with the carbon atoms to which they are bonded, form a ring structure with 4 to 20 ring members; a7 is an integer from 0 to 6; when a7 is 1, R 7a is a monovalent organic group with 1 to 20 carbon atoms, a hydroxyl group, a nitro group, or a halogen group; when a7 is 2 or more, multiple R 7a are the same or different and are monovalent organic groups with 1 to 20 carbon atoms, hydroxyl groups, nitro groups or halogen groups, or represent multiple R 7a Two of the carbon atoms are combined with each other and together with the carbon atoms to which they are bonded, form a ring structure with 3 to 20 ring members; t1 is an integer from 0 to 3; R 8a is a single bond or a divalent organic group with 1 to 20 carbon atoms; t2 is 0 or 1)

[0095] In the above formulas (7) and (8), R 1a 、R 2a 、R 3a 、R 4a and R 5a (hereinafter referred to as “R 1a ~R 5a”) include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted cycloalkyloxy group, an ester group, an alkylsulfonyl group, a cycloalkylsulfonyl group, a hydroxyl group, a carboxyl group, a cyano group, and a nitro group.

[0096] R 1a ~R 5a The alkyl group represented by may be linear or branched. The alkyl group preferably has 1 to 10 carbon atoms. 1a ~R 5a The alkyl group represented by is preferably a group having 1 to 5 carbon atoms, more preferably a methyl group, an ethyl group, an n-butyl group or a tert-butyl group. 1a ~R 5a Specific examples of the alkoxy group include groups having the alkyl groups exemplified above in the alkyl portion constituting the alkoxy group. The alkoxy group is preferably a methoxy group, an ethoxy group, an n-propoxy group, or an n-butoxy group.

[0097] R 1a ~R 5a The cycloalkyl group represented may be either monocyclic or polycyclic. Examples of monocyclic cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cyclooctyl. Examples of polycyclic cycloalkyl groups include norbornyl, adamantyl, tricyclodecyl, and tetracyclododecyl. 1a ~R 5a Specific examples of the cycloalkyloxy group include groups having the cycloalkyl groups exemplified above in the cycloalkyl moiety constituting the cycloalkyloxy group. 1a ~R 5a The cycloalkyloxy represented is preferably cyclopentyloxy or cyclohexyloxy.

[0098] In R 1a ~R 5a When the group has a substituent, examples of the substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxyl group, a carboxyl group, a cyano group, a nitro group, and an alkoxy group having 1 to 5 carbon atoms.

[0099] In R 1a ~R 5a In the case of an ester group (-COOR), the hydrocarbon portion (R) of the ester group may include the substituted or unsubstituted alkyl groups or substituted or unsubstituted cycloalkyl groups exemplified above. 1a ~R 5a In the case of an ester group, R 1a ~R 5a Preferably, it is methoxycarbonyl, ethoxycarbonyl or n-butoxycarbonyl. 1a ~R 5aIn the case of an alkylsulfonyl group, examples of the alkyl moiety constituting the alkylsulfonyl group include the substituted or unsubstituted alkyl groups exemplified above. 1a ~R 5a In the case of a cycloalkylsulfonyl group, examples of the alkyl portion constituting the cycloalkylsulfonyl group include the substituted or unsubstituted cycloalkyl groups exemplified above.

[0100] In the expression R 1a and R 2a In the case of a divalent group that is mutually bonded and links these bonded rings, examples of the divalent group include: -COO-, -OCO-, -CO-, -O-, -SO-, -SO2-, -S-, an alkanediyl group having 1 to 3 carbon atoms, an alkenediyl group having 2 or 3 carbon atoms, and a group having -O-, -S-, -COO-, -OCO-, -CO-, -SO-, or -SO2- between carbon-carbon bonds of ethylene. Among these, R 1a and R 2a It is preferably a single bond connecting the rings, or forming -O- or -S-.

[0101] a1 is preferably an integer from 0 to 2. When a1 is 1 or greater, R in the formula (7) 1a At least one of them is preferably a fluorine atom, an iodine atom or a trifluoromethyl group. a2 is preferably an integer from 0 to 2. When a2 is 1 or more, R in the formula (7) 2a At least one of them is preferably a fluorine atom, an iodine atom or a trifluoromethyl group. a3 is preferably an integer from 0 to 2. When a3 is 1 or more, R in formula (7) 3a At least one of them is preferably a fluorine atom, an iodine atom or a trifluoromethyl group. In particular, it is preferred that a1, a2 and a3 are all independently integers of 0 to 2, more preferably a1, a2 and a3 are all independently integers of 1 or 2, and at least one R in the formula (7) 1a , at least one R 2a and at least one R 3a are fluorine atom, iodine atom or trifluoromethyl group respectively.

[0102] a4 is preferably an integer from 0 to 2. When a4 is 1 or greater, R in the formula (8) 4a At least one of them is preferably a fluorine atom, an iodine atom or a trifluoromethyl group. a5 is preferably an integer from 0 to 2. When a5 is 1 or more, R in the formula (8) 5a At least one of them is preferably a fluorine atom, an iodine atom or a trifluoromethyl group. In particular, it is preferred that a4 and a5 are both independently an integer of 0 to 2, more preferably a4 and a5 are both independently 1 or 2, and at least one R in the formula (8) is 4a and at least one R 4aare fluorine atom, iodine atom or trifluoromethyl group respectively.

[0103] In the formula (9), R 6a and R 7a Examples of the monovalent organic group having 1 to 20 carbon atoms represented by include a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, -OR k 、-COOR k 、-O-CO-R k 、-OR kk -COOR k 、-R kk -CO-R k 、-OSO2-R k or -SO2-R k etc. R k is a monovalent hydrocarbon group having 1 to 10 carbon atoms. kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms. Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include the same group as R in the formula (G-1). 4 ~R 6 The same groups as those exemplified for the monovalent hydrocarbon groups represented by 6a and R 7a In the example, as the substituent for substituting the hydrogen atom possessed by the hydrocarbon group, the substituents mentioned above as R 1a ~R 5a The substituents that the groups represented by are the same as the groups exemplified.

[0104] As R 8a The divalent organic group represented by can be exemplified by 6a and R 7a The exemplified monovalent organic groups having 1 to 20 carbon atoms include groups obtained by removing one hydrogen atom.

[0105] In the above, R 6a and R 7a Preferably, the group is a linear or branched monovalent alkyl group, a monovalent fluoroalkyl group, a monovalent aromatic hydrocarbon group, -OSO2-R k or -SO2-R k a6 is preferably an integer from 0 to 2, more preferably 0 or 1. a7 is preferably an integer from 0 to 2, more preferably 0 or 1. t2 is preferably 0. t1 is preferably 2 or 3.

[0106] In the formula (1), a is preferably 1.

[0107] As M a+ Specific examples include cations represented by the following formulae. a+ It is not limited to these.

[0108] [Chemistry 13]

[0109]

[0110] [Chemistry 14]

[0111]

[0112] [Chemistry 15]

[0113]

[0114] [Chemistry 16]

[0115]

[0116] [Chemistry 17]

[0117]

[0118] Specific examples of the first structural unit include structural units represented by the following formulae. However, the first structural unit is not limited to the following specific examples.

[0119] [Chemistry 18]

[0120]

[0121] [Chemistry 19]

[0122]

[0123] [Chemistry 20]

[0124]

[0125] (Where M a+ is an a-valent cation; a is 1 or 2)

[0126] In the polymer [A], the content ratio of the first structural unit relative to all the structural units constituting the polymer [A] is preferably 1 mol% or more, more preferably 2 mol% or more, and further preferably 5 mol% or more. In addition, the content ratio of the first structural unit relative to all the structural units constituting the polymer [A] is preferably 50 mol% or less, more preferably 40 mol% or less, and further preferably 30 mol% or less. By setting the content ratio of the first structural unit to the above range, the sensitivity of the present composition can be improved, and the difference in developer solubility (solubility contrast) between the exposed portion and the unexposed portion can be improved, which can further expand the process margin during pattern formation, which is suitable in this respect.

[0127] (Other structural units)

[0128] The polymer [A] may contain a structural unit different from the first structural unit (hereinafter also referred to as "other structural unit") in addition to the first structural unit. Examples of the other structural unit include the second to fifth structural units shown below.

[0129] Second structural unit

[0130] The [A] polymer may also further include a structural unit having an aromatic ring and a hydroxyl group bonded to the aromatic ring (wherein the structural unit equivalent to the first structural unit is excluded; it is set as the "second structural unit"). By further including the second structural unit in the [A] polymer, the lithographic properties such as the LWR performance and the critical dimension uniformity (Critical Dimension Uniformity, CDU) performance of the present composition can be further improved, and the effect of suppressing the dissolution of the unexposed portion into the developer is high and the development defects can be sufficiently reduced, which is suitable in terms of these aspects. In particular, in pattern formation using exposure of radiation with a wavelength of less than 50nm such as an electron beam or EUV, a polymer comprising the second structural unit can be preferably applied. In the case of application to pattern formation using exposure of radiation with a wavelength of less than 50nm, the [A] polymer preferably includes the second structural unit.

[0131] Examples of the aromatic ring to which the hydroxyl group is bonded include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring. Among these, a benzene ring or a naphthalene ring is preferred, and a benzene ring is more preferred. In the second structural unit, the number of hydroxyl groups bonded to the aromatic ring is not particularly limited. The number of hydroxyl groups bonded to the aromatic ring in the second structural unit is preferably 1 to 3, more preferably 1 or 2.

[0132] As the second structural unit, for example, a structural unit represented by the following formula (ii) can be mentioned.

[0133] [Chemistry 21]

[0134]

[0135] (In formula (ii), R 11 is a hydrogen atom, a fluoro group, a methyl group or a trifluoromethyl group; L 2 is a single bond, an ether bond, a carbonyl group, an ester bond or an amide bond; Y 1 is a monovalent group having a hydroxyl group bonded to an aromatic ring)

[0136] In the formula (ii), from the viewpoint of copolymerizability of the monomer providing the second structural unit, R 11 It is preferably a hydrogen atom or a methyl group. 2 It is preferably a single bond or an ester bond.

[0137] Specific examples of the second structural unit include structural units represented by the following formulae.

[0138] [Chemistry 22]

[0139]

[0140] (Where R 11 is a hydrogen atom, a fluoro group, a methyl group or a trifluoromethyl group)

[0141] In polymer [A], the content of the second structural unit is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, relative to all the structural units constituting polymer [A]. Furthermore, the content of the second structural unit is preferably 90 mol% or less, more preferably 80 mol% or less, and even more preferably 60 mol% or less, relative to all the structural units constituting polymer [A]. The content of the second structural unit within this range is preferred because it can further improve the lithographic properties of the present composition.

[0142] Furthermore, the polymer [A] may contain a polymer containing a second structural unit separately from the polymer containing the first structural unit. From the perspective of obtaining a radiation-sensitive composition having excellent lithographic properties (such as LWR (Line Width Roughness) performance and CDU performance) and defect suppression, the present composition preferably contains, as the polymer [A], a polymer having the first structural unit and the second structural unit in the same molecule.

[0143] The third structural unit

[0144] The polymer [A] may further include a structural unit having an acid-dissociable group and not having an onium salt structure (referred to as a "third structural unit"). The acid-dissociable group contained in the third structural unit is preferably a group that replaces a hydrogen atom contained in an acid group such as a carboxyl group or a hydroxyl group, and is a group that dissociates upon the action of an acid. When the polymer [A] further includes the third structural unit, exposure of the present composition to acid generates an acid, and the acid-dissociable group in the third structural unit dissociates to generate an acid group, thereby changing the solubility of the polymer [A] in a developer, thereby imparting excellent lithographic properties to the present composition.

[0145] As the third structural unit, for example, a structural unit represented by the following formula (iii-1) (hereinafter also referred to as "structural unit (III-1)"), a structural unit represented by the following formula (iii-2) (hereinafter also referred to as "structural unit (III-2)"), and a structural unit represented by the following formula (iii-3) (hereinafter also referred to as "structural unit (III-3)") can be listed.

[0146] [Chemistry 23]

[0147]

[0148] (In formula (iii-1), R 12 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; R 13 is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms; R 14 and R 15 are independently a substituted or unsubstituted monovalent hydrocarbon group or aromatic heterocyclic group having 1 to 20 carbon atoms, or R 14 and R 15 Combined with R 14 and R 15 The carbon atoms bonded together form an alicyclic hydrocarbon structure with 3 to 20 carbon atoms; wherein, in R 13 When R is a hydrogen atom, 14 and R 15 Any one or both of them are monovalent unsaturated hydrocarbon groups or aromatic heterocyclic groups, or represent R 14 and R 15 Combined with R 14 and R 15 The bonded carbon atoms together form an unsaturated alicyclic hydrocarbon structure with 3 to 20 carbon atoms;

[0149] In formula (iii-2), R 16 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; L 3 is a single bond, -COO- or -CONH-; R 17 、R 18 and R 19 R are each independently a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted monovalent oxyhydrocarbon group having 1 to 20 carbon atoms; 35 is a monovalent substituent; g1 is an integer from 0 to 4;

[0150] In formula (iii-3), R 31 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; L 4 is a single bond, -COO- or -CONH-; R 32 、R 33 and R 34 R is independently a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted monovalent oxyhydrocarbon group having 1 to 20 carbon atoms; 33 and R 34 are independently a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted monovalent oxyhydrocarbon group having 1 to 20 carbon atoms, or R33 and R 34 Combined with R 33 and R 34 The carbon atoms bonded together form an alicyclic hydrocarbon structure with 3 to 20 carbon atoms; R 36 is a monovalent substituent; g2 is an integer from 0 to 4)

[0151] In the above formula (iii-1), from the viewpoint of providing copolymerizability of the monomer of the structural unit (III-1), R 12 In the formula (iii-2), from the viewpoint of copolymerizability of the monomer providing the structural unit (III-2), R 16 Preferably, it is a hydrogen atom. Similarly, R in the formula (iii-3) 31 Preferred is a hydrogen atom.

[0152] As R 13 ~R 15 、R 17 ~R 19 and R 32 ~R 34 The monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (G-1) includes, for example, a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and the like. Specific examples thereof include the following: 4 ~R 6 The groups exemplified as the monovalent hydrocarbon groups represented by are the same groups.

[0153] As R 14 and R 15 Combined with R 14 and R 15 The carbon atoms bonded together constitute an alicyclic hydrocarbon structure having 3 to 20 carbon atoms, and R 33 and R 34 Combined with R 33 and R 34 Specific examples of the alicyclic hydrocarbon structure having 3 to 20 carbon atoms formed by the carbon atoms bonded thereto include: 5 and R 6 The same structure as the structure exemplified in the description of .

[0154] As R 17 ~R 19 and R 32 ~R 34 The monovalent oxyhydrocarbon group having 1 to 20 carbon atoms represented by 13 ~R 15 、R 17 ~R19 and R 32 ~R 34 The carbon number of 1 to 20 monovalent hydrocarbon group and the example of the bonding side terminal contains an oxygen atom group. 17 ~R 19 and R 32 ~R 34 The monovalent oxyhydrocarbon group represented is preferably an alkoxy group, a cycloalkoxy group or a cycloalkylalkoxy group.

[0155] In R 13 ~R 19 or R 32 ~R 34 When the group represented by has a substituent, examples of the substituent include a halogen atom, a hydroxyl group, an alkoxy group having 1 to 3 carbon atoms, and the like. 14 and R 15 Combined with R 14 and R 15 When the carbon atoms to which they are bonded together form an alicyclic hydrocarbon structure having 3 to 20 carbon atoms, or R 33 and R 34 Combined with R 33 and R 34 When the bonded carbon atoms together constitute an alicyclic hydrocarbon structure having 3 to 20 carbon atoms, the substituents or alkyl groups exemplified above may be bonded to the ring.

[0156] As R 35 and R 36 Examples of the monovalent substituents represented include alkyl groups having 1 to 3 carbon atoms, alkoxy groups having 1 to 3 carbon atoms, hydroxyl groups, and halogen atoms (e.g., fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms). g1 and g2 are preferably 0 to 2, and more preferably 0 or 1.

[0157] Specific examples of the structural unit (III-1) include structural units represented by the following formulae.

[0158] [Chemistry 24]

[0159]

[0160] [Chemistry 25]

[0161]

[0162] [Chemistry 26]

[0163]

[0164] (Where R 12 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group)

[0165] Specific examples of the structural unit (III-2) include structural units represented by the following formulae.

[0166] [Chemistry 27]

[0167]

[0168] (Where R 16 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group)

[0169] Specific examples of the structural unit (III-3) include structural units represented by the following formulae.

[0170] [Chemistry 28]

[0171]

[0172] (Where R 31 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group)

[0173] When polymer [A] includes a third structural unit, the content of the third structural unit is preferably 20 mol% or more, more preferably 25 mol% or more, and even more preferably 30 mol% or more, relative to all the structural units constituting polymer [A]. Furthermore, the content of the third structural unit is preferably 80 mol% or less, more preferably 75 mol% or less, and even more preferably 70 mol% or less, relative to all the structural units constituting polymer [A]. Setting the content of the third structural unit within the above range is preferable in that the difference in dissolution rate of the exposed and unexposed portions in the developer solution can be further increased, thereby improving the pattern shape of the resist film.

[0174] In addition, the polymer [A] may also include a structural unit in which an acid-dissociable group and a hydroxyl group are bonded to the same or different aromatic rings. In this specification, a structural unit in which an acid-dissociable group and a hydroxyl group are bonded to the same or different aromatic rings is classified as a third structural unit.

[0175] ·The fourth structural unit

[0176] The polymer [A] may further include a structural unit having a lactone structure, a cyclic carbonate structure, a sultone structure, or a ring structure formed by combining two or more of these (excluding the structural units corresponding to the first to third structural units; these are referred to as "fourth structural units"). The inclusion of the fourth structural unit in the polymer [A] allows adjustment of the solubility in the developer, resulting in further optimization of the photolithographic properties of the present composition, which is desirable in this respect. Furthermore, the inclusion of the fourth structural unit in the polymer [A] improves the adhesion between the resist film obtained using the present composition and the substrate.

[0177] Examples of the fourth structural unit include structural units represented by the following formula.

[0178] [Chemistry 29]

[0179]

[0180] [Chemistry 30]

[0181]

[0182] [Chemistry 31]

[0183]

[0184] (Where R L1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group)

[0185] When polymer [A] contains a fourth structural unit, the proportion of the fourth structural unit relative to all structural units constituting polymer [A] is preferably 1 mol% or more, more preferably 3 mol% or more, and even more preferably 5 mol% or more. Furthermore, the proportion of the fourth structural unit relative to all structural units constituting polymer [A] is preferably 50 mol% or less, more preferably 30 mol% or less, and even more preferably 15 mol% or less. By setting the proportion of the fourth structural unit within this range, the lithographic properties of the present composition and the adhesion between the resist film obtained using the present composition and the substrate can be improved.

[0186] ·Fifth structural unit

[0187] The polymer [A] may further contain a structural unit having an alcoholic hydroxyl group (excluding the structural units corresponding to the first to fourth structural units; these are referred to as the "fifth structural unit"). In this specification, an "alcoholic hydroxyl group" refers to a group having a structure in which a hydroxyl group is directly bonded to an aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be a chain hydrocarbon group or an alicyclic hydrocarbon group. By further including the fifth structural unit, the solubility of the polymer [A] in a developer can be improved, thereby improving the lithographic properties of the present composition.

[0188] The fifth structural unit is preferably a structural unit derived from an unsaturated monomer having an alcoholic hydroxyl group. The unsaturated monomer is not particularly limited, and examples thereof include 3-hydroxyadamantan-1-yl (meth)acrylate and 2-hydroxyethyl (meth)acrylate.

[0189] When polymer [A] contains the fifth structural unit, the proportion of the fifth structural unit relative to all structural units constituting polymer [A] is preferably 1 mol% or more, more preferably 3 mol% or more. Furthermore, the proportion of the fifth structural unit relative to all structural units constituting polymer [A] is preferably 30 mol% or less, more preferably 20 mol% or less.

[0190] Examples of other structural units include, in addition to those described above, structural units containing a cyano group, a nitro group, or a sulfonamide group (specifically, structural units derived from 2-cyanomethyladamantan-2-yl (meth)acrylate, etc.), and structural units containing a non-acid-dissociable hydrocarbon group (specifically, structural units derived from styrene, structural units derived from vinylnaphthalene, structural units derived from n-pentyl (meth)acrylate, etc.). The content ratio of these structural units can be appropriately set for each structural unit within a range that does not impair the effects of the present disclosure.

[0191] In the present composition, the content of the polymer [A] is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 85% by mass or more, relative to the total amount of solid components contained in the present composition. In addition, the content of the polymer [A] is preferably 99% by mass or less, more preferably 98% by mass or less, and even more preferably 95% by mass or less, relative to the total amount of solid components contained in the present composition. The polymer [A] is preferably a base resin constituting the present composition. In this specification, the term "base resin" refers to a polymer component that accounts for 50% by mass or more of the total amount of solid components contained in the present composition. The present composition may contain only one type of polymer [A], or may contain two or more types.

[0192] The weight average molecular weight (Mw) of the polymer [A] in terms of polystyrene obtained by gel permeation chromatography (GPC) is preferably 1,000 or more, more preferably 2,000 or more, further preferably 3,000 or more, further more preferably 4,000 or more. Furthermore, the Mw is preferably 50,000 or less, more preferably 30,000 or less, further preferably 20,000 or less, further more preferably 15,000 or less. By setting the Mw of the polymer [A] within the above range, the coating properties of the present composition can be improved, and development defects can be sufficiently suppressed, which is preferable in this respect.

[0193] The ratio (Mw / Mn) of the polymer Mw to the polystyrene-equivalent number average molecular weight (Mn) obtained by GPC is preferably 5.0 or less, more preferably 3.0 or less, further preferably 2.0 or less, and further preferably 1.8 or less. Furthermore, Mw / Mn is generally 1 or greater, preferably 1.3 or greater. The polymer [A] can be synthesized, for example, by polymerizing monomers providing each structural unit in an appropriate solvent using a known free radical polymerization initiator or the like.

[0194] <Providing a monomer for the first structural unit and its synthesis>

[0195] The monomer providing the first structure (hereinafter also referred to as "compound (M)") is represented by the following formula (2).

[0196] [Chemistry 32]

[0197]

[0198] (In formula (2), R 1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; X 1 For single key, * 1 -COO-,* 1 -CONH-, or a divalent aromatic ring group; "* 1 " indicates that the 1 The bond of the carbon atom to which it is bonded; W 1 is an organic group with a valence of (r+2); X 2 for* 3 -COO- or -O-; "* 3 " indicates that 1 Bond of G 1 is an acid dissociative group; r is 1 or 2; when r is 2, the two G 1 Same or different; R 2 and R 3 are independently a fluorine atom or a fluoroalkyl group; M a+ is an a-valent cation; a is 1 or 2)

[0199] In the formula (2), R 1 、X 1 、W 1 、X 2 , G 1 , r, R 2 、R 3 and M a+ Specific examples and preferred examples of R in formula (1) 1 、X 1 、W 1 、X 2 , G 1 , r, R2 、R 3 and M a+ Same description as .

[0200] Compound (M) can be synthesized by appropriately combining conventional methods of organic chemistry. For example, the following examples include: 1 )-X 1 -W 1 (-(X 2 -G 1 ) r )-" and an aldehyde compound or ketone compound having a partial structure represented by "-C(R 2 )(R 3 )-SO3 - " is reacted in a suitable organic solvent and optionally in the presence of a catalyst; 1 )-X 1 -W 1 (-(X 2 -G 1 ) r )-" and a carboxylic acid having a partial structure represented by "-C(R 2 )(R 3 )-SO3 - " is a method of reacting a hydroxyl-containing compound of a partial structure represented by "H2C=C(R 1 )-X 1 -W 1 (-(X 2 -G 1 ) r )-" and a hydroxyl-containing compound having a partial structure represented by "-C(R 2 )(R 3 )-SO3 - " is a method for reacting a carboxylic acid having a partial structure represented by "-W in a suitable organic solvent and optionally in the presence of a catalyst; 1 (-(X 2 -G 1 ) r )-" and halide with a partial structure represented by "-C(R 2 )(R 3 )-SO3 - " is reacted in a suitable organic solvent and in the presence of a catalyst as needed, and "H2C=C(R 1 )-X 1 -" indicates the structure of the part with W 1The method for synthesizing compound (M) is not limited to the above method.

[0201] <[Z] Acid diffusion controller>

[0202] An acid diffusion controller is a component that inhibits the diffusion of acid generated in the resist film upon exposure of the composition, thereby suppressing the chemical reaction caused by the acid in the unexposed portion. By adding an acid diffusion controller to the composition, the photolithographic properties (LWR performance or CDU performance) of the composition can be improved. Furthermore, changes in the line width of the resist pattern caused by variations in the standing time from exposure to development can be suppressed, resulting in a radiation-sensitive composition with excellent process stability. Examples of acid diffusion controllers include nitrogen-containing compounds and photodegradable bases.

[0203] (Nitrogen-containing compounds)

[0204] As the nitrogen-containing compound, a known nitrogen-containing compound used in resist pattern formation can be used. Specific examples of the nitrogen-containing compound include amino-containing compounds (alkylamines, aromatic amines, polyamines, etc.), amide-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds (N-(undecane-1-ylcarbonyloxyethyl)morpholine, etc.), nitrogen-containing compounds having acid-dissociable groups (N-(tert-butoxycarbonyl)di-n-octylamine, N-tert-butoxycarbonyl-4-hydroxypiperidine, etc.). As the nitrogen-containing compound, one may be used alone, or two or more may be used in combination.

[0205] (Photodegradable base)

[0206] As a photodegradable base, a compound (hereinafter also referred to as "compound (z)") that generates an acid with a lower acidity than the acid generated by the [A] polymer upon exposure can be preferably used. In addition, the degree of acidity can be evaluated by the acid dissociation constant (pKa). The acid dissociation constant of the acid generated by the photodegradable base is usually greater than -3, preferably -1≦pKa≦7, and more preferably 0≦pKa≦5. The acid generated by the photodegradable base is a weak acid that does not induce the dissociation of the acid-dissociating group under normal conditions. In addition, the "normal conditions" mentioned here refer to the conditions of post-exposure baking (PEB) at 110°C for 60 seconds.

[0207] As compound (z), an onium salt containing a cation (more specifically, a radiation-sensitive onium cation) and an organic anion can be preferably used. From the perspective of making the photolithographic properties of the present composition good, compound (z) is preferably an onium salt that generates carboxylic acid, sulfonic acid or sulfonamide by exposure. In addition, from the perspective of being able to form a resist film with higher LWR performance, as compound (z), an onium salt having a sulfonium cation structure or an iodonium cation structure can be preferably used. As compound (z), one type can be used alone, or two or more types can be used in combination.

[0208] Preferred specific examples of the compound (z) include the following compounds (z1) and (z2).

[0209] Compound (z1): an onium salt containing an organic anion having an iodine atom and a cation

[0210] Compound (z2): an onium salt containing a cation having a fluorine atom and an organic anion

[0211] Hereinafter, the details of each compound will be described.

[0212] Compound (z1)

[0213] The organic anion (hereinafter also referred to as "iodine-containing anion") possessed by compound (z1) has no particular limitation on its structure as long as it has one or more iodine atoms. Examples of iodine-containing anions include sulfonate anion structures, imide anion structures, methyl anion structures, and carboxylate anion structures. Among these, the iodine-containing anion preferably has a sulfonate anion structure or a carboxylate anion structure, and more preferably has a carboxylate anion structure.

[0214] From the perspective of achieving high sensitivity of the present composition and ensuring a wider process margin during pattern formation, the number of iodine atoms possessed by the iodine-containing anion is preferably 2 or more, more preferably 3 or more. Furthermore, from the perspective of achieving a balance between the effect of expanding the process margin during pattern formation and the ease of synthesis of compound (z1), the number of iodine atoms possessed by the iodine-containing anion is preferably 10 or less, more preferably 8 or less.

[0215] The bonding position of the iodine atom in the iodine-containing anion is not particularly limited. In terms of the high improvement effect of the sensitivity of the present composition, the iodine-containing anion preferably contains an aromatic ring and an iodine atom bonded to the aromatic ring, and more preferably two or more iodine atoms are bonded to the aromatic ring. When the iodine-containing anion has two or more iodine atoms, the two or more iodine atoms may be bonded to the same aromatic ring in the iodine-containing anion, or may be bonded to different aromatic rings. The aromatic ring to which the iodine atom is bonded is preferably a benzene ring or a naphthalene ring, more preferably a benzene ring.

[0216] Specific examples of the iodine-containing anion include anions represented by the following formulae (z1-1) to (z1-7), respectively.

[0217] [Chemistry 33]

[0218]

[0219] (In formulas (z1-1) to (z1-7), X is independently a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, an amino group, or an amino group protected by an acid-dissociable group; wherein at least one of the multiple Xs in each formula is an iodine atom; R 71 is an alkanediyl group having 1 to 6 carbon atoms or a fluoroalkanediyl group having 1 to 6 carbon atoms; R 72 is a fluorinated divalent cyclic group; R 73 is an alkanediyl group having 1 to 6 carbon atoms; T 5 is an alkyl group or a cycloalkyl group)

[0220] In the above formulas (z1-1) to (z1-7), R 71 The fluoroalkanediyl group having 1 to 6 carbon atoms represented by R preferably has 1 to 4 carbon atoms, and specific examples thereof include -CF2-, -CF2-CF2-, -CH(CF3)-CF2-, -CH2-CF2-, -CF2-CH2-, -C(CF3)2-CH2-, and -CH2-C(CF3)2-. 71 The alkanediyl group having 1 to 6 carbon atoms represented by alkylene groups preferably has 1 to 3 carbon atoms, and more preferably is a methylene group or an ethylene group.

[0221] As R 72 The fluorinated divalent cyclic group represented by is a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms in which one or more hydrogen atoms are substituted with fluorine atoms. Specific examples of the alicyclic hydrocarbon group and the aromatic hydrocarbon group include the following: 4 ~R 6 The groups exemplified as the monovalent hydrocarbon group having 1 to 20 carbon atoms are the same groups as those exemplified above.

[0222] Specific examples of iodine-containing anions include organic anions represented by the following formulae: However, the iodine-containing anions are not limited to the following structures.

[0223] [Chemistry 34]

[0224]

[0225] The cation possessed by the compound (z1) preferably has a sulfonium cation structure or an iodonium cation structure, and more preferably has a triarylsulfonium cation structure or a diaryliodonium cation structure. Specific examples of the cation possessed by the compound (z1) include the cation (M) possessed by the first structural unit. a+ The cation contained in the compound (z1) may also contain a fluorine atom.

[0226] Specific examples of compound (z1) include onium salts formed by arbitrarily combining the iodine-containing anions and cations listed above. Further specific examples of these include onium salts comprising a cation represented by any one of formulae (7) to (9) and an organic anion represented by any one of formulae (z1-1) to (z1-7).

[0227] Compound (z2)

[0228] The cation (hereinafter also referred to as "fluorine-containing cation") possessed by the compound (z2) is not particularly limited in structure as long as it has one or more fluorine atoms. From the viewpoint of sensitivity, the fluorine-containing cation preferably has at least one group (hereinafter also referred to as "group Rf) selected from the group consisting of a fluoroalkyl group and a fluoro group (excluding the fluoro group in the fluoroalkyl group). 1 ”).

[0229] When the fluorine-containing cation has a fluoroalkyl group, the fluoroalkyl group may be linear or branched. Specific examples of the fluoroalkyl group include the following: 2 or R 3 The fluoroalkyl group represented by is the same as the group exemplified.

[0230] From the perspective of sensitivity, the base Rf 1 It is preferably a fluoro group, a trifluoromethyl group, a 2,2,2-trifluoroethyl group or a perfluoroethyl group, and more preferably a fluoro group or a trifluoromethyl group.

[0231] In the fluorinated cations with the group Rf 1 In terms of further improving the sensitivity and LWR performance of the present composition, the base Rf 1The number of is preferably two or more, more preferably three or more. In addition, from the perspective of achieving a balance between the effect of improving sensitivity and ease of synthesis, the group Rf 1 The number of is preferably ten or less, more preferably eight or less, further preferably seven or less, and further more preferably six or less.

[0232] In addition, the fluorine-containing cation has a fluoroalkyl group as the group Rf 1 In the case of the fluorinated cation, the number of fluoroalkyl groups in the fluorinated cation becomes the number of radicals Rf 1 Therefore, for example, in the case where the fluorine-containing cation has two trifluoromethyl groups (-CF3), the number of radicals Rf 1 In addition, when the fluorine-containing cation has one fluorine group (-F) and two trifluoromethyl groups (-CF3) bonded to the aromatic ring, the number of groups Rf 1 The number becomes three.

[0233] The radical Rf in fluorinated cations 1 The bonding position of is not particularly limited. In terms of the high effect of improving the sensitivity of the present composition, it is preferably the group Rf 1 More than one of the groups Rf is directly bonded to the aromatic ring contained in the fluorine-containing cation, and more preferably two or more groups Rf 1 Directly bonded to the aromatic ring. In addition, the fluorinated cation has two or more radicals Rf 1 In the case of two or more radicals Rf 1 It may be bonded to the same aromatic ring in the fluorinated cation or to different aromatic rings. Among them, the fluorinated cation is particularly preferably one having one or more aromatic rings bonded to the sulfonium cation or the iodonium cation (hereinafter also referred to as "aromatic ring R A ”), and the radical Rf 1 With aromatic ring R A Direct bonding.

[0234] As aromatic ring R A , for example, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, etc. Among these, the aromatic ring R A Preferably, it is a benzene ring or a naphthalene ring, and most preferably a benzene ring. A Bonding group Rf 1 The total number of is preferably two or more, more preferably three or more. In addition, from the perspective of achieving a balance between the effect of improving sensitivity and the ease of synthesis of compound (z2), the aromatic ring R A Bonding group Rf 1The total number of is preferably ten or less, more preferably eight or less, further preferably seven or less, further more preferably six or less. A Bonding group Rf 1 When the total number of Rf is two or more, 1 It may be bonded to the same aromatic ring in the fluorine-containing cation or to different aromatic rings.

[0235] From the viewpoint of sensitivity, the fluorine-containing cation preferably has a triarylsulfonium cation structure or a diaryliodonium cation structure. Specifically, as preferred examples of the fluorine-containing cation, there can be cited: R in the formula (7) 1a 、R 2a and R 3a One or more of the groups Rf 1 The cation, R in the formula (8) 4a and R 5a One or more of the groups Rf 1 The cation, R in the formula (9) 6a Rf 1 cations.

[0236] Specific examples of fluorine-containing cations include M in the first structural unit. a+ The cations exemplified as specific examples have a group Rf 1 The fluorine-containing cation is not limited to the above structure.

[0237] Examples of the organic anion possessed by compound (z2) include anions having a sulfonate anion structure, an imide anion structure, a methyl anion structure, or a carboxylate anion structure. Among these, the organic anion possessed by compound (z2) preferably has a sulfonate anion structure or a carboxylate anion structure, and more preferably has a carboxylate anion structure. Furthermore, the organic anion possessed by compound (z2) may also have an iodine atom.

[0238] Specific examples of the organic anion contained in the compound (z2) include organic anions represented by the following formulae and organic anions exemplified as iodine-containing anions. However, the organic anion contained in the compound (z2) is not limited to these structures.

[0239] [Chemistry 35]

[0240]

[0241] Specific examples of compound (z2) include onium salts obtained by arbitrarily combining the fluorine-containing cations and organic anions exemplified above. Further specific examples of these include, for example, onium salts containing R in formula (7) above. 1a 、R 2a and R 3a One or more of the groups Rf 1 The cation, R in the formula (8) 4a and R 5a One or more of the groups Rf 1 The cation, or R in the formula (9) 6a Rf 1 cation, and an onium salt of the above-mentioned exemplified organic anion.

[0242] In addition, as the photodegradable base, a compound different from compound (z1) and compound (z2) (hereinafter also referred to as "other photodegradable base") may be used. Examples of other photodegradable bases include onium salts containing cations not having a fluorine atom among the cations listed as cations constituting compound (z1) and compound (z2), and anions not having an iodine atom among the anions listed as anions constituting compound (z1) and compound (z2); and compounds in which a group having an anionic structure is bonded to an aryl group in a triarylsulfonium cation structure or a diaryliodonium cation structure (for example, compounds represented by the following formulas (z3-1) to (z3-3), respectively).

[0243] [Chemistry 36]

[0244]

[0245] In terms of being able to achieve a good balance in improving sensitivity, LWR performance and process margin during pattern formation, the acid diffusion controller formulated in the present composition is preferably the photodegradable base mentioned above, and more preferably at least one selected from the group consisting of compound (z1) and compound (z2).

[0246] When the present composition contains an acid diffusion controller, the content of the acid diffusion controller in the present composition is preferably set to 1 mol part or more, more preferably 2 mol parts or more, and further preferably 5 mol parts or more, relative to 100 mol parts of the total amount of the monomer (compound (M)) providing the first structural unit in the polymer [A] and the radiation-sensitive acid generator [B] contained in the present composition. In addition, the content of the acid diffusion controller is preferably set to 150 mol parts or less, more preferably 140 mol parts or less, and further preferably 135 mol parts or less, relative to 100 mol parts of the total amount of the monomer providing the first structural unit in the polymer [A] and the radiation-sensitive acid generator [B] contained in the present composition. By setting the content of the acid diffusion controller to the above range, the LWR performance of the present composition can be further improved. As the acid diffusion controller, one type can be used alone, or two or more types can be used in combination.

[0247] <[B]Radiosensitive acid generator>

[0248] The radiation-sensitive acid generator is not particularly limited, and known radiation-sensitive acid generators used in resist pattern formation can be suitably used. The radiation-sensitive acid generator formulated in the present composition is, for example, an onium salt comprising a radiation-sensitive onium cation and an organic anion. The radiation-sensitive acid generator is typically a compound that induces dissociation of an acid-dissociable group under the aforementioned conventional conditions, thereby generating an acid (preferably a strong acid such as a sulfonic acid, an imidic acid, or a methylated acid) in the composition having a higher acidity than that generated by a photodegradable base.

[0249] When an onium salt is used as the radiation-sensitive acid generator, the onium cation possessed by the radiation-sensitive acid generator is preferably a sulfonium cation or an iodonium cation, and among them, a triarylsulfonium cation or a diaryliodonium cation is preferred. Specific examples of these include the same cations as those exemplified as the cations represented by formula (7) and formula (8).

[0250] The organic anion possessed by the radiation-sensitive acid generator is not particularly limited as long as it is a compound that generates an acid upon exposure of the present composition, but is preferably a sulfonate anion, an imide anion, or a methide anion.

[0251] Specific examples of the organic anion constituting the radiation-sensitive acid generator include anions represented by the following formulas. However, the organic anion constituting the radiation-sensitive acid generator is not limited to the following structure.

[0252] [Chemistry 37]

[0253]

[0254] [Chemistry 38]

[0255]

[0256] When the present composition contains a radiation-sensitive acid generator, the amount of the radiation-sensitive acid generator is preferably 1 part by mass or more, more preferably 2 parts by mass or more, per 100 parts by mass of the polymer [A]. Furthermore, the amount of the radiation-sensitive acid generator is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, per 100 parts by mass of the polymer [A]. The radiation-sensitive acid generators may be used alone or in combination of two or more.

[0257] [D] Solvent

[0258] The solvent [D] is not particularly limited as long as it can dissolve or disperse the components formulated in the present composition. Examples of the solvent [D] include alcohols, ethers, ketones, amides, esters, and hydrocarbons.

[0259] Examples of alcohols include aliphatic monoalcohols having 1 to 18 carbon atoms, such as 4-methyl-2-pentanol and n-hexanol; alicyclic monoalcohols having 3 to 18 carbon atoms, such as cyclohexanol; polyols having 2 to 18 carbon atoms, such as 1,2-propylene glycol; and partial ethers of polyols having 3 to 19 carbon atoms, such as propylene glycol monomethyl ether. Examples of ethers include dialkyl ethers, such as diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, diisopentyl ether, dihexyl ether, and diheptyl ether; cyclic ethers, such as tetrahydrofuran and tetrahydropyran; and aromatic ring-containing ethers, such as diphenyl ether and anisole.

[0260] Examples of ketones include chain ketones such as acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, diethyl ketone, methyl isobutyl ketone, 2-heptanone, ethyl n-butyl ketone, methyl n-hexyl ketone, diisobutyl ketone, and trimethylnonanone; cyclic ketones such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, and methylcyclohexanone; 2,4-pentanedione, acetonylacetone, acetophenone, and diacetone alcohol; and amides such as cyclic amides such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone; and chain amides such as N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, and N-methylpropionamide.

[0261] Examples of esters include monocarboxylic acid esters such as n-butyl acetate, ethyl lactate, and methyl 2-hydroxyisobutyrate; polyol carboxylic acid esters such as propylene glycol diacetate; polyol partial ether carboxylic acid esters such as propylene glycol monomethyl ether acetate; polycarboxylic acid diesters such as diethyl oxalate; carbonates such as dimethyl carbonate and diethyl carbonate; and cyclic esters such as γ-butyrolactone. Examples of hydrocarbons include aliphatic hydrocarbons having 5 to 12 carbon atoms such as n-pentane and n-hexane; and aromatic hydrocarbons having 6 to 16 carbon atoms such as toluene and xylene.

[0262] The solvent [D] preferably comprises at least one selected from the group consisting of esters and ketones, and more preferably comprises at least one selected from the group consisting of polyol partial ether carboxylic acid esters and cyclic ketones. One or more solvents [D] may be used.

[0263] <[F] High fluorine content polymer>

[0264] The [F] high fluorine content polymer (hereinafter also referred to as "[F] polymer") is a polymer having a higher mass content of fluorine atoms than the [A] polymer. The [F] polymer can be contained in the present composition as a hydrophobic additive, for example.

[0265] The fluorine atom content of the polymer [F] is not particularly limited as long as it is greater than that of the polymer [A]. The fluorine atom content of the polymer [F] is preferably 1% by mass or more, more preferably 4% by mass or more, and most preferably 7% by mass or more. In addition, the fluorine atom content of the polymer [F] is preferably 60% by mass or less, more preferably 40% by mass or less. The fluorine atom content (mass %) of the polymer can be determined by 13 C-NMR ( 13 C-Nuclear Magnetic Resonance, 13 The structure of the polymer is determined by C-NMR spectroscopy and the like, and is calculated based on the structure.

[0266] When the present composition contains polymer [F], the content of polymer [F] in the present composition is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 0.5 parts by mass or more, relative to 100 parts by mass of polymer [A]. Furthermore, the content of polymer [F] relative to 100 parts by mass of polymer [A] is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less. Furthermore, the present composition may contain only one type of polymer [F], or two or more types.

[0267] <Other optional ingredients>

[0268] The present composition may further contain components other than the polymer [A], acid diffusion controller [Z], radiation-sensitive acid generator [B], solvent [D], and high-fluorine polymer [F] (hereinafter referred to as "other optional components"). Examples of other optional components include surfactants, compounds containing an alicyclic skeleton (e.g., 1-adamantanecarboxylic acid, 2-adamantanone, tert-butyl deoxycholate, etc.), sensitizers, polarization promoters, and nitrogen-containing compounds. The content of these other optional components in the present composition can be appropriately selected based on the individual components within a range that does not impair the effects of the present disclosure.

[0269] <Method for producing radiation-sensitive composition>

[0270] The present composition can be manufactured, for example, by the following manner: [A] polymer and, in addition, optionally [D] solvent and other components are mixed in a desired ratio, preferably using a filter (for example, a filter having a pore size of about 0.2 μm) etc. to filter the obtained mixture. The solid component concentration of the present composition is preferably more than 0.1% by mass, more preferably more than 0.5% by mass, and then preferably more than 1% by mass. In addition, the solid component concentration of the present composition is preferably less than 50% by mass, more preferably less than 20% by mass, and then preferably less than 5% by mass. By setting the solid component concentration of the present composition to the range, the coating property can be made good, and the shape of the resist pattern can be made good, which is suitable in this respect.

[0271] The present composition thus obtained can be used as a positive-type pattern-forming composition for forming a pattern using an alkaline developer, or as a negative-type pattern-forming composition using a developer containing an organic solvent.

[0272] 《Resist pattern forming method》

[0273] The resist pattern forming method disclosed herein includes: a process of applying the present composition on one side of a substrate (hereinafter also referred to as a "coating process"); a process of exposing the resist film obtained by the coating process (hereinafter also referred to as an "exposure process"); and a process of developing the resist film exposed by the exposure process (hereinafter also referred to as a "development process"). Examples of patterns formed by the resist pattern forming method disclosed herein include line and space patterns, hole patterns, and the like. In the resist pattern forming method disclosed herein, since the present composition is used to form a resist film, a resist pattern having good sensitivity, good photolithographic characteristics, and few development defects can be formed. Each process will be described below.

[0274] [Coating process]

[0275] In the coating process, a resist film is formed on the substrate by applying the present composition on one side of the substrate. As the substrate for forming the resist film, a conventionally known one can be used, for example, a silicon wafer, silicon dioxide, an aluminum-coated wafer, etc. In addition, an organic or inorganic anti-reflective film disclosed in Japanese Patent Laid-Open No. 59-93448 can also be formed on the substrate for use. As the coating method of the present composition, for example, spin coating, cast coating, roller coating, etc. can be mentioned. After coating, soft baking (SB, also called pre-baking) can be performed to volatilize the solvent in the coating film. The temperature of SB is preferably 60°C or more, more preferably 80°C or more. In addition, the temperature of SB is preferably 140°C or less, more preferably 120°C or less. The time of SB is preferably 5 seconds or more, more preferably 10 seconds or more. In addition, the time of SB is preferably 600 seconds or less, more preferably 300 seconds or less. The average thickness of the formed resist film is preferably 10 nm to 1,000 nm, more preferably 20 nm to 500 nm.

[0276] [Exposure process]

[0277] In the exposure process, the resist film obtained by the coating process is exposed. The exposure is carried out in the following manner: through a photomask, optionally through an immersion medium such as water to irradiate the resist film with radiation. As radiation, depending on the line width of the target pattern, for example, electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light (EUV), X-rays, and gamma rays can be listed; charged particle beams such as electron beams and alpha rays, etc. Among these, the radiation irradiated to the resist film formed using the present composition is preferably far ultraviolet light, EUV or an electron beam, more preferably ArF excimer laser light (wavelength 193nm), KrF excimer laser light (wavelength 248nm), EUV or an electron beam, further preferably ArF excimer laser light, EUV or an electron beam, further more preferably EUV or an electron beam, and most preferably EUV.

[0278] A post-exposure bake (PEB) is preferably performed after the exposure to promote the dissociation of acid-dissociable groups in the exposed portions of the resist film by the acid generated from the compound ([A] polymer or [B] radiation-sensitive acid generator) that generates acid upon exposure. This PEB can increase the difference in solubility in the developer between the exposed and unexposed portions. The PEB temperature is preferably 50°C or higher, more preferably 80°C or higher. Furthermore, the PEB temperature is preferably 180°C or lower, more preferably 130°C or lower. The PEB time is preferably 5 seconds or longer, more preferably 10 seconds or longer. Furthermore, the PEB time is preferably 600 seconds or shorter, more preferably 300 seconds or shorter.

[0279] [Development Process]

[0280] In the development step, the exposed resist film is developed. This forms the desired resist pattern. After development, the film is typically rinsed with a rinse solution such as water or alcohol and then dried. The development method in the development step can be either alkaline or organic solvent.

[0281] In the case of alkali development, examples of the developer used for development include alkaline aqueous solutions prepared by dissolving at least one alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, and 1,5-diazabicyclo-[4.3.0]-5-nonene. Among these, a TMAH aqueous solution is preferred, and a 2.38% by mass TMAH aqueous solution is more preferred.

[0282] In the case of organic solvent development, examples of the developer include organic solvents such as hydrocarbons, ethers, esters, ketones, and alcohols; and solvents containing these organic solvents, or one or more thereof. Examples of organic solvents used as developer include those listed as [E] solvents in the description of this composition. Among these, esters and ketones are preferred. Esters are preferably acetates, and n-butyl acetate is more preferred. Ketones are preferably chain ketones, and 2-heptanone is 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, further preferably 95% by mass or more, and most preferably 99% by mass or more. Components other than the organic solvent in the developer include, for example, water and silicone oil.

[0283] Examples of the developing method include: a method of immersing a substrate in a tank filled with a developer for a fixed period of time (immersion method); a method of performing development by utilizing surface tension to deposit the developer on the surface of the substrate and allowing the developer to remain stationary for a fixed period of time (puddle method); a method of spraying the developer onto the surface of the substrate (spray method); a method of continuously spraying the developer onto the substrate rotating at a fixed speed while scanning a developer spray nozzle at a fixed speed (dynamic distribution method), etc.

[0284] Example

[0285] The present disclosure is described in detail below based on the examples, but the present disclosure is not limited to these examples. In addition, unless otherwise specified, the "parts" and "%" in the following examples are based on mass. The following shows the measurement methods of various physical property values.

[0286] [Weight average molecular weight (Mw) and number average molecular weight (Mn) of polymer]

[0287] The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer were measured by gel permeation chromatography (GPC) using Tosoh GPC columns (two "G2000HXL", one "G3000HXL", and one "G4000HXL") under the following conditions.

[0288] Eluent: Tetrahydrofuran (Wako Pure Chemical Industries, Ltd.)

[0289] Flow rate: 1.0 mL / min

[0290] Sample concentration: 1.0 mass%

[0291] Sample injection volume: 100 μL

[0292] Column temperature: 40°C

[0293] Detector: Differential refractometer

[0294] Standard material: monodisperse polystyrene

[0295] <Synthesis of Compound (M)>

[0296] [Synthesis Example 1-1] (Synthesis of Monomer (M-15))

[0297] The monomer (M-15) was synthesized according to the following reaction scheme.

[0298] [Chemistry 39]

[0299]

[0300] To a reaction vessel, 40 mmol of 5-formylsalicylic acid, 200 mmol of tert-butyl alcohol, and 8 mmol of DMAP (4-dimethylaminopyridine) were added and stirred for 1 hour. A solution of 44 mmol of DCC (N,N'-dicyclohexylcarbodiimide) dissolved in 80 mL of THF (tetrahydrofuran) was added dropwise, and the mixture was stirred at room temperature for 3 hours. The solid was filtered and purified by silica gel chromatography to obtain (ppM-15).

[0301] To a reaction vessel, 30 mmol of (ppM-15), 39 mmol of methacrylic acid, 39 mmol of EDC (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide), 6 mmol of DMAP, and 40 mL of DCM (dichloromethane) were added and stirred at room temperature for 2 hours. 20 mL of 2M hydrochloric acid was added, and the organic layer was separated. The mixture was washed twice with 40 mL of saturated sodium bicarbonate aqueous solution and once with 40 mL of ultrapure water to obtain (pM-15).

[0302] To a reaction vessel, 20 mmol of the compound represented by the formula (S-1), 21 mmol of (pM-15), 4 mmol of pTsOH (p-toluenesulfonic acid), and 100 mL of toluene were added. A Dean-Stark tube was set in the reaction vessel and stirred at reflux for 4 hours. 50 mL of saturated sodium bicarbonate aqueous solution was added to separate the organic layer. After drying the organic layer with sodium sulfate, the solvent was removed. Purification was performed by silica gel chromatography to obtain a monomer (M-15).

[0303] [Synthesis Example 1-2] (Synthesis of Monomer (M-16))

[0304] A monomer (M-16) was synthesized in the same manner as in Synthesis Example 1-1, except that the substrate used was appropriately selected.

[0305] [Chemistry 40]

[0306]

[0307] [Synthesis Example 1-3] (Synthesis of Monomer (M-17))

[0308] The monomer (M-17) was synthesized according to the following reaction scheme.

[0309] [Chemistry 41]

[0310]

[0311] To a reaction vessel, 30 mmol of 3-hydroxyphthalic anhydride, 150 mmol of potassium carbonate, and 100 mL of acetone were added. After stirring for 1 hour, 60 mmol of 4-(chloromethyl)styrene was added dropwise, and the mixture was stirred at 55°C for 5 hours. After cooling to room temperature, the precipitated solid was filtered, and the filtrate was concentrated. Purification by silica gel column chromatography yielded (ppM-17).

[0312] To a reaction vessel, 30 mmol of 2-phenyl-2-propanol, 30 mmol of potassium carbonate, 20 mmol of (ppM-17), and 100 mL of acetone were added and stirred at reflux for 5 hours. After cooling to room temperature, the precipitated solid was filtered and the filtrate was concentrated. Purification by silica gel column chromatography afforded (pM-17).

[0313] To a reaction vessel were added 13 mmol of (pM-17), 10 mmol of the compound represented by the formula (S-2), 13 mmol of EDC, 2 mmol of DMAP, and 40 mL of dichloromethane, and the mixture was stirred for 2 hours. 40 mL of 2M hydrochloric acid was added, the organic layer was separated, and the mixture was washed twice with 40 mL of saturated sodium bicarbonate aqueous solution and once with 40 mL of ultrapure water. The mixture was purified by silica gel column chromatography to obtain monomer (M-17).

[0314] [Synthesis Example 1-4] (Synthesis of Monomer (M-18))

[0315] The monomer (M-18) was synthesized according to the following reaction scheme.

[0316] [Chemistry 42]

[0317]

[0318] To a reaction vessel, 40 mmol of 5-formylsalicylic acid, 80 mmol of 2-(4-iodophenyl)-2-propanol, and 8 mmol of DMAP were added and stirred for 1 hour. A solution of 44 mmol of DCC dissolved in 40 mL of tetrahydrofuran was added dropwise, and the mixture was stirred at room temperature for 3 hours. The solid was filtered and purified by silica gel chromatography to obtain (pppM-16).

[0319] To a reaction vessel, 30 mmol of (pppM-18), 39 mmol of methacrylic acid, 39 mmol of EDC, 6 mmol of DMAP, and 50 mL of dichloromethane were added and stirred at room temperature for 2 hours. 50 mL of 2M hydrochloric acid was added, and the organic layer was separated. The mixture was washed twice with 50 mL of saturated sodium bicarbonate aqueous solution and once with 50 mL of ultrapure water to obtain (pppM-18).

[0320] 20 mmol of (ppM-18) and 40 mL of tetrahydrofuran were added to a reaction vessel, and the mixture was stirred at 0°C for 30 minutes. Sodium borohydride was added, and the mixture was stirred at 0°C for 1 hour. 40 mL of saturated aqueous ammonium chloride was added, and the mixture was extracted with 100 mL of ethyl acetate to obtain (pM-18).

[0321] To the reaction vessel, 13 mmol of (pM-18), 10 mmol of the compound represented by the formula (S-3), 13 mmol of EDC, 2 mmol of DMAP, and 20 mL of dichloromethane were added and stirred at room temperature for 2 hours. 20 mL of 2M hydrochloric acid was added and the organic layer was separated. After washing twice with 20 mL of saturated sodium bicarbonate aqueous solution, 20 mL of ultrapure water were used for washing once. Silica gel column chromatography was used to refine the product to obtain monomer (M-18).

[0322] [Synthesis Example 1-5] (Synthesis of Monomer (M-19))

[0323] The monomer (M-19) was synthesized according to the following reaction scheme.

[0324] [Chemistry 43]

[0325]

[0326] 40 mmol of 5-vinylsalicylic acid, 80 mmol of 1-phenylcyclohexanol, and 8 mmol of DMAP were added to a reaction vessel, and the mixture was stirred at room temperature for 1 hour. A solution of 44 mmol of DCC dissolved in 40 mL of tetrahydrofuran was added dropwise, and the mixture was stirred at room temperature for 3 hours. The solid was filtered and purified by silica gel chromatography to obtain (pM-19).

[0327] To the reaction vessel, 13 mmol of (pM-19), 10 mmol of the compound represented by the formula (S-4), 13 mmol of EDC, 2 mmol of DMAP, and 20 mL of dichloromethane were added and stirred at room temperature for 2 hours. 20 mL of 2M hydrochloric acid was added and the organic layer was separated. After washing twice with 20 mL of saturated sodium bicarbonate aqueous solution, 20 mL of ultrapure water were used for washing once. Silica gel column chromatography was used for purification to obtain monomer (M-19).

[0328] [Synthesis Example 1-6] (Synthesis of Monomer (M-20))

[0329] The monomer (M-20) was synthesized according to the following reaction scheme.

[0330] [Chemistry 44]

[0331]

[0332] To a reaction vessel, 30 mmol of 3,5-diiodosalicylic acid, 39 mmol of methacrylic acid, 39 mmol of EDC, 6 mmol of DMAP, and 50 mL of dichloromethane were added and stirred at room temperature for 2 hours. 50 mL of 2M hydrochloric acid was added, and the organic layer was separated. The mixture was washed twice with 50 mL of saturated sodium bicarbonate solution and once with 50 mL of ultrapure water to obtain (ppM-20).

[0333] To a reaction vessel, 20 mmol of (ppM-20), 40 mL of tetrahydrofuran, and 0.1 mL of N,N-dimethylformamide were added, stirred, and 40 mmol of oxalyl chloride was added dropwise. After stirring at room temperature for 1 hour, a solution of 30 mmol of tert-butyl acetoacetate and 30 mmol of sodium tert-butoxide dissolved in 40 mL of acetonitrile was added dropwise. 50 mL of saturated aqueous ammonium chloride solution was added, the organic layer was separated, and then washed with 50 mL of ultrapure water. Purification was performed using silica gel column chromatography to obtain (pM-20).

[0334] The compound represented by the formula (S-5) 20mmol, (pM-20) 21mmol, pTsOH 4mmol, and toluene 100mL were added to the reaction vessel. A Dean-Stark tube was set in the reaction vessel and heated with stirring under reflux for 4 hours. 50mL of saturated sodium bicarbonate aqueous solution was added to separate the organic layer. After the organic layer was dried using sodium sulfate, the solvent was removed. Silica gel chromatography was used to refine the monomer (M-20).

[0335] [Synthesis Example 1-7] (Synthesis of Monomer (M-21))

[0336] The monomer (M-21) was synthesized according to the following reaction scheme.

[0337] [Chemistry 45]

[0338]

[0339] To a reaction vessel, 30 mmol of 3,5-diiodosalicylic acid, 39 mmol of 4-(hydroxymethyl)styrene, 39 mmol of EDC, 6 mmol of DMAP, and 50 mL of dichloromethane were added and stirred at room temperature for 2 hours. 50 mL of 2M hydrochloric acid was added, and the organic layer was separated. The mixture was washed twice with 50 mL of saturated sodium bicarbonate aqueous solution and once with 50 mL of ultrapure water to obtain (ppM-21).

[0340] To a reaction vessel, 29.74 mmol of (ppM-21), 148.7 mmol of potassium carbonate, and 100 mL of acetone were added. After stirring for 1 hour, 59.47 mmol of tert-butyl 4-chloroacetoacetate was added dropwise, and the mixture was heated and stirred at reflux for 5 hours. After cooling to room temperature, the precipitated solid was filtered, and the filtrate was concentrated. Purification by silica gel column chromatography yielded (pM-21).

[0341] The compound represented by the formula (S-6) 20mmol, (pM-21) 21mmol, pTsOH 4mmol, and toluene 100mL were added to the reaction vessel. A Dean-Stark tube was set in the reaction vessel and heated with stirring under reflux for 4 hours. 50mL of saturated sodium bicarbonate aqueous solution was added to separate the organic layer. After the organic layer was dried using sodium sulfate, the solvent was removed. Silica gel chromatography was used to refine the monomer (M-21).

[0342] [Synthesis Example 1-8] (Synthesis of Monomer (M-22))

[0343] The monomer (M-22) was synthesized according to the following reaction scheme.

[0344] [Chemistry 46]

[0345]

[0346] To the reaction vessel were added 29.74 mmol of the compound represented by the formula (S-7), 148.7 mmol of potassium carbonate, and 100 mL of acetone. After stirring for 1 hour, 59.47 mmol of tert-butyl 4-chloroacetoacetate was added dropwise, and the mixture was heated and stirred at reflux for 5 hours. After cooling to room temperature, the precipitated solid was filtered, and the filtrate was concentrated. Purification was performed by silica gel column chromatography to obtain (pM-22).

[0347] To a reaction vessel, 20 mmol of (pM-22), 100 mmol of sodium tert-butoxide, and 80 mL of acetonitrile were added. After stirring for 1 hour, 40 mmol of 4-(chloromethyl)styrene was added dropwise, and the mixture was heated and stirred at 60°C for 5 hours. After cooling to room temperature, the precipitated solid was filtered, and the filtrate was concentrated. Purification was performed by silica gel column chromatography to obtain monomer (M-22).

[0348] [Synthesis Example 1-9, Synthesis Example 1-10] (Synthesis of Monomer (M-23) to Monomer (M-24))

[0349] Monomer (M-23) and monomer (M-24) were synthesized in the same manner as in Synthesis Example 1-8, except that the substrate used was appropriately selected.

[0350] [Chemistry 47]

[0351]

[0352] [Synthesis Example 1-11] (Synthesis of Monomer (M-25))

[0353] The monomer (M-25) was synthesized according to the following reaction scheme.

[0354] [Chemistry 48]

[0355]

[0356] To the reaction vessel were added 29.74 mmol of 3,5-diiodo-4-hydroxystyrene, 148.7 mmol of potassium carbonate, and 100 mL of acetone. After stirring for 1 hour, 59.47 mmol of tert-butyl 4-chloroacetoacetate was added dropwise, and the mixture was heated and stirred at reflux for 5 hours. After cooling to room temperature, the precipitated solid was filtered, and the filtrate was concentrated. Purification was performed by silica gel column chromatography to obtain (pM-25).

[0357] The compound represented by the formula (S-8) 20mmol, (pM-25) 21mmol, pTsOH 4mmol, and toluene 100mL were added to the reaction vessel. A Dean-Stark tube was set in the reaction vessel, and heated with stirring under reflux for 4 hours. 50mL of saturated sodium bicarbonate aqueous solution was added to separate the organic layer. After the organic layer was dried using sodium sulfate, the solvent was removed. Silica gel chromatography was used to refine the monomer (M-25).

[0358] [Synthesis Example 1-12] (Synthesis of Monomer (M-26))

[0359] The monomer (M-26) was synthesized according to the following reaction scheme.

[0360] [Chemistry 49]

[0361]

[0362] To a reaction vessel, 40 mmol of the compound represented by formula (S-9), 200 mmol of tert-butyl alcohol, and 8 mmol of DMAP were added and stirred for 1 hour. A solution of 44 mmol of DCC dissolved in 40 mL of tetrahydrofuran was added dropwise, and the mixture was stirred at room temperature for 3 hours. The solid was filtered and purified by silica gel chromatography to obtain (ppM-26).

[0363] To a reaction vessel, 30 mmol of (ppM-26), 39 mmol of methacrylic acid, 39 mmol of EDC, 6 mmol of DMAP, and 20 mL of dichloromethane were added and stirred at room temperature for 2 hours. 20 mL of 2M hydrochloric acid was added, and the organic layer was separated. The mixture was washed twice with 20 mL of saturated sodium bicarbonate aqueous solution and once with 20 mL of ultrapure water to obtain (pM-26).

[0364] To the reaction vessel, 13 mmol of (pM-26), 10 mmol of the compound represented by the formula (S-10), 13 mmol of EDC, 2 mmol of DMAP, and 20 mL of dichloromethane were added and stirred at room temperature for 2 hours. 20 mL of 2 M hydrochloric acid was added and the organic layer was separated. After washing twice with 20 mL of saturated sodium bicarbonate aqueous solution, 20 mL of ultrapure water were used for washing once. Silica gel column chromatography was used to refine the product to obtain a monomer (M-26).

[0365] [Synthesis Example 1-13] (Synthesis of Monomer (M-27))

[0366] A monomer (M-27) was synthesized in the same manner as in Synthesis Example 1-12, except that the substrate used was appropriately selected.

[0367] [Chemistry 50]

[0368]

[0369] [Synthesis Example 1-14] (Synthesis of Monomer (M-28))

[0370] The monomer (M-28) was synthesized according to the following reaction scheme.

[0371] [Chemistry 51]

[0372]

[0373] To the reaction vessel, 29.74 mmol of tert-butyl 5-vinylsalicylate, 148.7 mmol of potassium carbonate, and 100 mL of acetone were added. After stirring for 1 hour, 59.47 mmol of the compound represented by the formula (S-12) was added, and the mixture was heated and stirred at reflux for 5 hours. After cooling to room temperature, the precipitated solid was filtered, and the filtrate was concentrated. Refined by silica gel column chromatography to obtain (pM-28).

[0374] The compound represented by the formula (S-13) 20mmol, (pM-28) 21mmol, pTsOH 4mmol, and toluene 100mL were added to the reaction vessel. A Dean-Stark tube was set in the reaction vessel, and heated with stirring under reflux for 4 hours. 50mL of saturated sodium bicarbonate aqueous solution was added to separate the organic layer. After the organic layer was dried using sodium sulfate, the solvent was removed. Silica gel chromatography was used to refine the monomer (M-28).

[0375] [Synthesis Example 1-15] (Synthesis of Monomer (M-29))

[0376] A monomer (M-29) was synthesized in the same manner as in Synthesis Example 1-14, except that the substrate used was appropriately selected.

[0377] [Chemistry 52]

[0378]

[0379] [Synthesis Example 1-16] (Synthesis of Monomer (M-30))

[0380] The monomer (M-30) was synthesized according to the following reaction scheme.

[0381] [Chemistry 53]

[0382]

[0383] To a reaction vessel, 30 mmol of 2,3,5,6-tetrafluoro-4-hydroxybenzoic acid, 39 mmol of 4-(hydroxymethyl)styrene, 39 mmol of EDC, 6 mmol of DMAP, and 50 mL of dichloromethane were added and stirred for 2 hours. 50 mL of 2M hydrochloric acid was added, and the organic layer was separated. The mixture was washed twice with 50 mL of saturated sodium bicarbonate solution and once with 50 mL of ultrapure water to obtain (ppM-30).

[0384] To a reaction vessel, 29.74 mmol of (ppM-30), 148.7 mmol of potassium carbonate, and 100 mL of acetone were added. After stirring for 1 hour, 59.47 mmol of tert-butyl 4-chloroacetoacetate was added dropwise, and the mixture was heated and stirred at reflux for 5 hours. After cooling to room temperature, the precipitated solid was filtered, and the filtrate was concentrated. Purification by silica gel column chromatography yielded (pM-30).

[0385] The compound represented by the formula (S-14) 20mmol, (pM-30) 21mmol, pTsOH 4mmol, and toluene 100mL were added to the reaction vessel. A Dean-Stark tube was set in the reaction vessel, and heated with stirring under reflux for 4 hours. 50mL of saturated sodium bicarbonate aqueous solution was added to separate the organic layer. After the organic layer was dried using sodium sulfate, the solvent was removed. Silica gel chromatography was used to refine the monomer (M-30).

[0386] [Synthesis Example 1-17] (Synthesis of Monomer (M-31))

[0387] The monomer (M-31) was synthesized according to the following reaction scheme.

[0388] [Chemistry 54]

[0389]

[0390] To a reaction vessel were added 30 mmol of 5-acetylsalicylic acid, 39 mmol of the compound represented by formula (S-15), 39 mmol of EDC, 6 mmol of DMAP, and 50 mL of dichloromethane, and stirred for 2 hours. 50 mL of 2M hydrochloric acid was added, and the organic layer was separated. The mixture was washed twice with 50 mL of saturated sodium bicarbonate aqueous solution and once with 50 mL of ultrapure water to obtain (pM-31).

[0391] To a reaction vessel, 29.74 mmol of (pM-31), 148.7 mmol of potassium carbonate, and 100 mL of acetone were added. After stirring for 1 hour, 59.47 mmol of chloromethyl methyl ether was added, and the mixture was heated and stirred at reflux for 5 hours. After cooling to room temperature, the precipitated solid was filtered, and the filtrate was concentrated. Purification was performed by silica gel column chromatography to obtain monomer (M-31).

[0392] [Synthesis Example 1-18] (Synthesis of Monomer (M-32))

[0393] The monomer (M-32) was synthesized according to the following reaction scheme.

[0394] [Chemistry 55]

[0395]

[0396] 30 mmol of 5-vinyl salicylaldehyde, 100 mL of dichloromethane, and 2 mL of concentrated sulfuric acid were added to the reaction vessel. Isobutylene gas (30 mL) was blown in and added, and the mixture was stirred at room temperature for 6 hours. 80 mL of saturated aqueous sodium bicarbonate solution was added, and the organic layer was separated. The organic layer was dried over sodium sulfate and the solvent was removed. Silica gel chromatography was used for purification to obtain a monomer (pM-32).

[0397] The compound represented by the formula (S-16) 20mmol, (pM-32) 21mmol, pTsOH 4mmol, and toluene 100mL were added to the reaction vessel. A Dean-Stark tube was set in the reaction vessel and heated with stirring under reflux for 4 hours. 50mL of saturated sodium bicarbonate aqueous solution was added to separate the organic layer. After the organic layer was dried using sodium sulfate, the solvent was removed. Silica gel chromatography was used to refine the monomer (M-32).

[0398] 2. Synthesis of base resin

[0399] [Synthesis Examples 2-1 to 2-35] Synthesis of Base Resins

[0400] The monomers were combined according to the composition shown in Table 1 below and copolymerized in tetrahydrofuran (THF) solvent. After crystallization in methanol and repeated washing with hexane, the mixture was separated and dried to obtain base resins A-1 to A-35. The resin Mw and dispersity (Mw / Mn) were measured by gel permeation chromatography (GPC) using Tosoh GPC columns (two "G2000HXL", one "G3000HXL", and one "G4000HXL") under the following conditions.

[0401] Eluent: Tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd.)

[0402] Flow rate: 1.0 mL / min

[0403] Sample concentration: 1.0 mass%

[0404] Sample injection volume: 100 μL

[0405] Column temperature: 40°C

[0406] Detector: Differential refractometer

[0407] Standard material: monodisperse polystyrene

[0408] [Table 1]

[0409]

[0410] The monomers used in the polymerization are shown below.

[0411] [Chemistry 56]

[0412]

[0413] [Chemistry 57]

[0414]

[0415] [Chemistry 58]

[0416]

[0417] [Chemistry 59]

[0418]

[0419] 4. Preparation and evaluation of radiation-sensitive resin compositions

[0420] The compounds used for preparing the radiation-sensitive resin composition are shown below.

[0421] <[A] Base resin>

[0422] A-1 to A-35: Polymers obtained in Synthesis Examples 2-1 to 2-35 <[B] Radiation-sensitive acid generator>

[0423] B-1 to B-4: Compounds represented by the following formulas (B-1) to (B-4) respectively

[0424] [Chemistry 60]

[0425]

[0426] <[Z] Acid diffusion controller>

[0427] Z-1 to Z-4: compounds represented by the following formulas (Z-1) to (Z-4) respectively

[0428] [Chemistry 61]

[0429]

[0430] [D] Solvent

[0431] D-1: Propylene glycol monomethyl ether

[0432] D-2: Propylene glycol 1-monomethyl ether

[0433] <Preparation of Radiation-Sensitive Composition>

[0434] [Example 1]

[0435] A radiation-sensitive composition (R-1) was prepared by mixing 100 parts by mass of a polymer (A-1) as a base resin, 20 mol% of a compound (Z-1) as an acid diffusion inhibitor [Z] relative to the amount of the monomer providing the first structural unit contained in 100 parts by mass of the polymer (A-1), and 2,000 parts by mass of a compound (D-1) and 4,800 parts by mass of a compound (D-2) as a solvent [D].

[0436] [Examples 2 to 40 and Comparative Examples 1 and 2]

[0437] Radiation-sensitive compositions (R-2) to (R-40) and radiation-sensitive compositions (CR-1) and (CR-2) were prepared in the same manner as in Example 1, except that the components were used in the types and amounts shown in Table 2 below. Furthermore, in Examples 34 to 37, an acid diffusion inhibitor (Z) was added so that the amount of the acid diffusion suppressant (Z) was 20 mol % relative to the total amount of the monomer providing the first structural unit contained in 100 parts by mass of the base resin (A) and the amount of the radiation-sensitive acid generator (B).

[0438] [Table 2]

[0439]

[0440] <Formation of Resist Pattern>

[0441] Each of the prepared radiation-sensitive compositions was applied using a spin coater (CLEAN TRACK ACT12, manufactured by Tokyo Electron) onto the surface of a 12-inch silicon wafer, which had been coated with a 40 nm thick underlayer film (AL412, manufactured by Brewer Science). After a soft bake at 130°C for 60 seconds, the film was cooled at 23°C for 30 seconds to form a 50 nm thick resist film. Next, the resist film was irradiated with EUV light using an EUV exposure system (model "NXE3300," manufactured by ASML, numerical aperture (NA) = 0.33, illumination conditions: conventional s = 0.89, mask: imecDEFECT32FFR02). Subsequently, a PEB was performed at 110°C for 60 seconds. Next, development was performed at 23° C. for 30 seconds using a 2.38% by mass TMAH aqueous solution to form a positive-type 32 nm line and space pattern.

[0442] <Evaluation>

[0443] Each resist pattern formed above was measured according to the following method to evaluate the sensitivity, LWR performance, and process margin of each radiation-sensitive composition. Furthermore, a scanning electron microscope ("CG-4100" from Hitachi High-Technologies Corporation) was used to measure the length of the resist pattern. The evaluation results are shown in Table 3 below.

[0444] [sensitivity]

[0445] In the formation of the resist pattern, the exposure amount for forming a 32 nm line and space pattern was set as the optimal exposure amount, and the optimal exposure amount was set as the sensitivity (mJ / cm 2 ). The smaller the sensitivity value is, the more a desired resist pattern can be formed with a smaller exposure amount, and thus it is good.

[0446] [LWR performance]

[0447] The formed resist pattern was observed from above using the scanning electron microscope. Line widths were measured at a total of 50 points at random locations. The 3-sigma value was calculated from the distribution of these measured values ​​and designated as LWR (unit: nm). Regarding LWR performance, a smaller LWR value indicates less line jitter and better results.

[0448] [Process Margin (Min CD)]

[0449] During the formation of the resist pattern, the line width is measured while reducing the exposure dose, and the minimum line width without line breakage or collapse is defined as Min CD (unit: nm). The smaller the Min CD value, the wider and better the process margin for line formation.

[0450] [Table 3]

[0451]

[0452] As is clear from the results of Table 3, the radiation-sensitive compositions of Examples 1 to 40 were superior to the radiation-sensitive compositions of Comparative Examples 1 and 2 in sensitivity, LWR performance, and process margin.

[0453] Based on the above results, the radiation-sensitive composition of the present disclosure, which contains a polymer containing a structural unit represented by formula (1), has good sensitivity to exposure light, a wide process margin, and excellent LWR performance. Therefore, the radiation-sensitive composition of the present disclosure and the resist pattern formation method of the present disclosure using the same are suitable for processing of semiconductor devices, etc., which are expected to be further miniaturized in the future.

Claims

1. A radiation-sensitive composition comprising a polymer containing a structural unit represented by the following formula (1). [Chemistry 1] (In formula (1), R 1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 For single key, * 1 -COO-,* 1 -CONH-, or a divalent aromatic ring group. "* 1 " indicates that the 1 The bond between the carbon atoms to which it is bonded. 1 X is an organic group with a valence of (r+2). 2 for* 3 -COO- or -O-. "* 3 " indicates that 1 The bonding bond of G 1 is an acid dissociative group. r is 1 or 2. In the case where r is 2, the two G 1 Same or different. 2 and R 3 are independently a fluorine atom or a fluoroalkyl group. a+ is an a-valent cation. a is 1 or 2). 2 . The radiation-sensitive composition according to claim 1 , further comprising a compound (z) which generates an acid having a lower acidity than the acid generated by the polymer upon exposure. 3 . The radiation-sensitive composition according to claim 2 , comprising an onium salt composed of an organic anion having an iodine atom and a cation as the compound (z). 4 . The radiation-sensitive composition according to claim 3 , wherein the organic anion has an aromatic ring and an iodine atom bonded to the aromatic ring. The radiation-sensitive composition according to claim 2 , comprising an onium salt composed of a cation having a fluorine atom and an organic anion as the compound (z).

6. The radiation-sensitive composition according to claim 5, wherein the cation in the compound (z) has an aromatic ring R bonded to a sulfonium cation or an iodonium cation. A , In the aromatic ring R A On the bond, there is a group selected from fluoroalkyl and fluoro groups (wherein, at least one group selected from the group consisting of (excluding the fluorine group in the fluoroalkyl group).

7. The radiation-sensitive composition according to claim 1, wherein W in the formula (1) 1 It has at least one ring selected from the group consisting of an aromatic hydrocarbon ring, an aliphatic hydrocarbon ring and an aliphatic heterocyclic ring, and a "-X 2 -G 1 "The base represented by ".

8. The radiation-sensitive composition according to claim 1, wherein W in the formula (1) 1 It has a chain structure, on which "-X 2 -G 1 "The base represented by ". 9 . The radiation-sensitive composition according to claim 1 , wherein the polymer further comprises a structural unit having an aromatic ring and a hydroxyl group bonded to the aromatic ring. 10 . The radiation-sensitive composition according to claim 1 , wherein the polymer further comprises a structural unit having an acid-dissociable group and not having an onium salt structure.

11. A method for forming a resist pattern, comprising: A process for forming a resist film on a substrate using the radiation-sensitive composition according to any one of claims 1 to 10; a step of exposing the resist film to light; and A step of developing the exposed resist film.

12. A polymer comprising a structural unit represented by the following formula (1). [Chemistry 2] (In formula (1), R 1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; X 1 For single key, * 1 -COO-,* 1 -CONH-, or a divalent aromatic ring group. "* 1 " indicates that the 1 The bond between the carbon atoms to which it is bonded. 1 X is an organic group with a valence of (r+2). 2 for* 3 -COO- or -O-. "* 3 " indicates that 1 The bonding bond of G 1 is an acid dissociative group. r is 1 or 2. In the case where r is 2, the two G 1 Same or different. 2 and R 3 are independently a fluorine atom or a fluoroalkyl group. a+ is an a-valent cation. a is 1 or 2).

13. A compound represented by the following formula (2). [Chemistry 3] (In formula (2), R 1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 For single key, * 1 -COO-,* 1 -CONH-, or a divalent aromatic ring group. "* 1 " indicates that the 1 The bond between the carbon atoms to which it is bonded. 1 X is an organic group with a valence of (r+2). 2 for* 3 -COO- or -O-. "* 3 " indicates that 1 The bonding bond of G 1 is an acid dissociative group. r is 1 or 2. In the case where r is 2, the two G 1 Same or different. 2 and R 3 are independently a fluorine atom or a fluoroalkyl group. a+ is an a-valent cation. a is 1 or 2).

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