Resist composition and method for forming a resist pattern

Abstract

To provide a resist composition good in sensitivity, resolution, roughness reduction and pattern shape, and a resist pattern forming method.SOLUTION: In the resist composition which generates an acid upon exposure and whose solubility in a developer changes by the action of an acid, a resin component whose solubility changes by the action of an acid contains an acrylate structural unit having a phenolic hydroxyl group in a side chain.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resist composition and a method of forming a resist pattern. [Background technology]

[0002] In recent years, advances in lithography technology have led to rapid advances in the miniaturization of patterns in the manufacturing of semiconductor devices and liquid crystal display devices. A common method for achieving this miniaturization is to shorten the wavelength (increase the energy) of the exposure light source.

[0003] Resist materials are required to have lithography properties such as sensitivity to these exposure light sources and resolution capable of reproducing patterns with minute dimensions. To satisfy these requirements, a chemically amplified resist composition has been used, which contains a base component whose solubility in a developer changes due to the action of acid, and an acid generator component that generates acid upon exposure.

[0004] In the formation of a resist pattern, the behavior of the acid generated from the acid generator component upon exposure is considered to be one factor that has a significant effect on the lithography properties. In response to this, a chemically amplified resist composition has been proposed which contains, in addition to an acid generator component, an acid diffusion controller that controls the diffusion of the acid generated from the acid generator component upon exposure. For example, Patent Document 1 discloses a resist composition containing a resin component whose solubility in a developer changes under the action of an acid, an acid generator component, and an amine compound as an acid diffusion controller. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-140289 Summary of the Invention [Problem to be solved by the invention]

[0006] As lithography technology continues to advance and resist patterns become increasingly finer, for example, EUV and EB lithography are aiming to form fine patterns of several tens of nanometers. As resist pattern dimensions become smaller, resist materials are required to improve lithography properties such as sensitivity, resolution, and roughness reduction without making trade-offs. In addition, resist patterns with high rectangularity are also required to be formed.

[0007] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a resist composition that exhibits excellent sensitivity, resolution, roughness reduction properties, and pattern shape, and a method of forming a resist pattern that uses the resist composition. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention employs the following configuration. That is, a first aspect of the present invention is a resist composition that generates an acid upon exposure and whose solubility in a developer changes due to the action of the acid, the resist composition comprising: a resin component (A1) whose solubility in a developer changes due to the action of the acid; and a photodegradable base (D0) that controls the diffusion of the acid generated by exposure, wherein the resin component (A1) has a structural unit (a0) represented by the following general formula (a0-1), and the acid dissociation constant (pKa) of the conjugate acid of the photodegradable base (D0) is 4.0 or less.

[0009] [ka] [In the formula, R 01 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. 01 is a single bond or a divalent linking group. 01 represents a hydrocarbon group which may have a substituent. 02 is a single bond or a divalent linking group. 02is a hydrogen atom, a hydroxy group, or a hydrocarbon group which may have a substituent. Ar is a benzene ring or a naphthalene ring. Ra 01 and Ra 02 are mutually bonded to form Ra 01 and Ya 02 and the secondary carbon atom to which Ya is bonded. 02 And, Ya 02 The carbon atom of Ar to which Ra is bonded 02 may form a ring with the carbon atom of Ar to which n is bonded. n01 is an integer of 1 to 6, as far as valence allows.

[0010] A second aspect of the present invention is a method of forming a resist pattern, comprising the steps of forming a resist film on a support using the resist composition related to the first aspect, exposing the resist film to light, and developing the exposed resist film to form a resist pattern. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a resist composition that exhibits excellent sensitivity, resolution, roughness reduction, and pattern shape, and a method of forming a resist pattern that uses this resist composition. DETAILED DESCRIPTION OF THE INVENTION

[0012] In this specification and claims, the term "aliphatic" is defined as a relative concept to aromatic, and refers to groups, compounds, etc. that do not have aromaticity. Unless otherwise specified, the term "alkyl group" includes linear, branched, and cyclic monovalent saturated hydrocarbon groups. The same applies to alkyl groups in alkoxy groups. Unless otherwise specified, the term "alkylene group" includes linear, branched and cyclic divalent saturated hydrocarbon groups. The "halogen atom" includes a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The term "structural unit" refers to a monomer unit that constitutes a polymeric compound (resin, polymer, copolymer). The phrase "may have a substituent" includes both the case where a hydrogen atom (-H) is replaced with a monovalent group and the case where a methylene group (-CH2-) is replaced with a divalent group. The term "exposure" is a general concept that includes irradiation with radiation.

[0013] A "base component" is an organic compound that has film-forming ability. Organic compounds used as base components are broadly divided into non-polymers and polymers. Non-polymers typically have a molecular weight of 500 or more and less than 4000. Hereinafter, the term "low molecular weight compound" refers to a non-polymer with a molecular weight of 500 or more and less than 4000. Polymers typically have a molecular weight of 1000 or more. Hereinafter, the terms "resin," "high molecular weight compound," or "polymer" refer to a polymer with a molecular weight of 1000 or more. The molecular weight of a polymer is determined by the weight average molecular weight converted into polystyrene by GPC (gel permeation chromatography).

[0014] The term "derived structural unit" refers to a structural unit formed by cleavage of a multiple bond between carbon atoms, such as an ethylenic double bond. In the "acrylic acid ester", the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. αx ) is an atom or group other than a hydrogen atom. αx ) is substituted with a substituent containing an ester bond, or αx This also includes α-hydroxyacrylic esters in which the hydroxyl group is substituted with a hydroxyalkyl group or a group that modifies the hydroxyl group. Unless otherwise specified, the α-carbon atom of an acrylic ester refers to the carbon atom to which the carbonyl group of acrylic acid is bonded. Hereinafter, an acrylic ester in which the hydrogen atom bonded to the carbon atom at the α-position is substituted with a substituent may be referred to as an α-substituted acrylic ester.

[0015] The term "derivative" encompasses compounds in which the hydrogen atom at the α-position of the target compound is substituted with another substituent, such as an alkyl group or a halogenated alkyl group, as well as derivatives thereof. Examples of such derivatives include compounds in which the hydrogen atom of a hydroxyl group of a target compound, which may have the hydrogen atom at the α-position substituted with a substituent, is substituted with an organic group; and compounds in which a substituent other than a hydroxyl group is bonded to a target compound, which may have the hydrogen atom at the α-position substituted with a substituent. Unless otherwise specified, the α-position refers to the first carbon atom adjacent to the functional group. The substituents that replace the hydrogen atom at the α-position of hydroxystyrene include R αx The same can be mentioned.

[0016] In this specification and claims, some structures represented by chemical formulas may have asymmetric carbon atoms, and may exist as enantiomers or diastereomers. In such cases, a single chemical formula represents all isomers. These isomers may be used alone or as a mixture.

[0017] (Resist composition) The resist composition of this embodiment generates an acid upon exposure, and the solubility in a developer changes due to the action of the acid. This resist composition contains a base component (A) (hereinafter also referred to as "component (A)") whose solubility in a developer changes under the action of an acid, and a photodegradable base (D0) (hereinafter also referred to as "component (D0)") whose conjugate acid has an acid dissociation constant (pKa) of 4.0 or less.

[0018] When a resist film is formed using the resist composition of this embodiment and then subjected to selective exposure, acid is generated in the exposed areas of the resist film, and the solubility of the component (A) in a developer changes due to the action of the acid. However, the solubility of the component (A) in a developer does not change in the unexposed areas of the resist film, resulting in a difference in solubility in a developer between the exposed and unexposed areas of the resist film.

[0019] The resist composition of this embodiment may be a positive resist composition or a negative resist composition. Furthermore, the resist composition of this embodiment may be for use in an alkaline development process in which an alkaline developer is used for the development treatment during resist pattern formation, or may be for use in a solvent development process in which an organic developer is used for the development treatment. In other words, the resist composition of this embodiment is a "positive resist composition for an alkaline developing process" that forms a positive resist pattern in an alkaline developing process, and a "negative resist composition for a solvent developing process" that forms a negative resist pattern in a solvent developing process.

[0020] <Component (A)> In the resist composition of this embodiment, the component (A) contains a resin component (A1) (hereinafter also referred to as "component (A1)") whose solubility in a developer changes under the action of acid. This resin component (A1) has a structural unit (a0) represented by general formula (a0-1). As the component (A), at least the component (A1) is used, and at least one of another polymeric compound and a low molecular weight compound may be used in combination with the component (A1).

[0021] In the resist composition of this embodiment, the component (A) may use either a single type of compound, or a combination of two or more types of compounds.

[0022] About component (A1) The component (A1) is a resin component whose solubility in a developer changes under the action of an acid. The component (A1) has a structural unit (a0) represented by the following general formula (a0-1). The component (A1) may contain other structural units in addition to the structural unit (a0), as necessary.

[0023] <Constituent unit (a0)> The structural unit (a0) is a structural unit represented by the following general formula (a0-1).

[0024] [ka] [In the formula, R 01 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. 01 is a single bond or a divalent linking group. 01 represents a hydrocarbon group which may have a substituent. 02 is a single bond or a divalent linking group. 02 is a hydrogen atom, a hydroxy group, or a hydrocarbon group which may have a substituent. Ar is a benzene ring or a naphthalene ring. Ra 01 and Ra 02 are mutually bonded to form Ra 01 and Ya 02 and the secondary carbon atom to which Ya is bonded. 02 And, Ya 02 The carbon atom of Ar to which Ra is bonded 02 may form a ring with the carbon atom of Ar to which n is bonded. n01 is an integer of 1 to 6, as far as valence allows.

[0025] In the formula (a0-1), R 01 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R 01 The alkyl group having 1 to 5 carbon atoms in the formula (I) is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. R 01 As the alkyl group, a hydrogen atom or a methyl group is particularly preferred in view of industrial availability.

[0026] In the formula (a0-1), Ya 01 is a single bond or a divalent linking group. Ya 01 The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom.

[0027] Optionally substituted divalent hydrocarbon groups: Ya 01 When is a divalent hydrocarbon group which may have a substituent, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0028] Ya 01 Aliphatic hydrocarbon groups in The aliphatic hydrocarbon group refers to a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated. Examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, and an aliphatic hydrocarbon group containing a ring in its structure.

[0029] Linear or branched aliphatic hydrocarbon groups The linear aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specific examples include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)5-]. The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0030] The linear or branched aliphatic hydrocarbon group may or may not have a substituent, such as a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, or a carbonyl group.

[0031] Aliphatic hydrocarbon groups containing rings in the structure Examples of the aliphatic hydrocarbon group containing a ring in its structure include a cyclic aliphatic hydrocarbon group (a group in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring) which may contain a substituent containing a heteroatom in the ring structure, a group in which the cyclic aliphatic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and a group in which the cyclic aliphatic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. Examples of the straight-chain or branched-chain aliphatic hydrocarbon group include the same as those described above. The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably has 3 to 12 carbon atoms. The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0032] The cyclic aliphatic hydrocarbon group may or may not have a substituent, such as an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, or a carbonyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and still more preferably a methoxy group or an ethoxy group. The halogen atom as the substituent is preferably a fluorine atom. Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms. In the cyclic aliphatic hydrocarbon group, some of the carbon atoms constituting the ring structure may be substituted with a substituent containing a heteroatom, and the heteroatom-containing substituent is preferably -O-, -C(=O)-O-, -S-, -S(=O)2-, or -S(=O)2-O-.

[0033] Ya 01 Aromatic hydrocarbon groups in The aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, still more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. However, this number of carbon atoms does not include the number of carbon atoms in the substituent. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of the aromatic heterocycle include pyridine rings and thiophene rings. Specific examples of the aromatic hydrocarbon group include groups in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle (arylene groups or heteroarylene groups); groups in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and groups in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group) has been substituted with an alkylene group (e.g., groups in which one hydrogen atom has been further removed from the aryl group in an arylalkyl group such as a benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, or 2-naphthylethyl group). The alkylene group bonded to the aryl group or heteroaryl group preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

[0034] The aromatic hydrocarbon group may have a hydrogen atom substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, and a hydroxyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Examples of the alkoxy group, halogen atom and halogenated alkyl group as the substituent include those exemplified as the substituent substituting the hydrogen atom of the cyclic aliphatic hydrocarbon group.

[0035] Divalent linking groups containing heteroatoms: Ya 01 is a divalent linking group containing a hetero atom, preferred examples of the linking group include -O-, -C(=O)-O-, -OC(=O)-, -C(=O)-, -OC(=O)-O-, -C(=O)-NH-, -NH-, -NH-C(=NH)- (H may be substituted with a substituent such as an alkyl group or an acyl group), -S-, -S(=O)2-, -S(=O)2-O-, and groups represented by the general formula -Y 21 -OY 22 -, -Y 21 -O-, -Y 21 -C(=O)-O-, -C(=O)-OY 21 -, -[Y 21 -C(=O)-O] m” -Y 22 -, -Y 21 -OC(=O)-Y 22 -or- Y 21 -S(=O)2-OY 22 -, wherein Y 21 and Y 22 are each independently a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m″ is an integer of 0 to 3. When the divalent linking group containing a hetero atom is -C(=O)-NH-, -C(=O)-NH-C(=O)-, -NH-, or -NH-C(=NH)-, the H may be substituted with a substituent such as an alkyl group, an acyl group, etc. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8, and particularly preferably 1 to 5 carbon atoms. General formula-Y 21 -OY22 -, -Y 21 -O-, -Y 21 -C(=O)-O-, -C(=O)-OY 21 -, -[Y 21 -C(=O)-O] m” -Y 22 -, -Y 21 -OC(=O)-Y 22 -or- Y 21 -S(=O)2-OY 22 -Medium, Y 21 and Y 22 are each independently a divalent hydrocarbon group which may have a substituent. Examples of the divalent hydrocarbon group include the above-mentioned Ya 01 Examples of the divalent linking group include the same groups as those (divalent hydrocarbon groups which may have a substituent) mentioned in the description of the divalent linking group in the above. Y 21 As the alkyl group, a straight-chain aliphatic hydrocarbon group is preferred, a straight-chain alkylene group is more preferred, a straight-chain alkylene group having 1 to 5 carbon atoms is even more preferred, and a methylene group or ethylene group is particularly preferred. Y 22 is preferably a linear or branched aliphatic hydrocarbon group, more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group. Formula − [Y 21 -C(=O)-O] m” -Y 22 In the group represented by -, m" is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and particularly preferably 1. That is, in the group represented by the formula -[Y 21 -C(=O)-O] m” -Y 22 The group represented by - is a group represented by the formula -Y 21 -C(=O)-OY 22 Particularly preferred is a group represented by the formula -(CH2) a’ -C(=O)-O-(CH2) b’In the formula, a' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, even more preferably 1 or 2, and most preferably 1. b' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, even more preferably 1 or 2, and most preferably 1.

[0036] Among the above, Ya 01 is preferably a single bond, an ester bond [—C(═O)—O—], an ether bond (—O—), a linear or branched alkylene group, or a combination thereof. 01 is preferably a single bond.

[0037] In the formula (a0-1), Ra 01 is a hydrocarbon group which may have a substituent. Ra 01 The hydrocarbon group in may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a cyclic hydrocarbon group or a chain hydrocarbon group. Ra 01 Specific examples of the hydrocarbon group which may have a substituent include a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, and a chain alkenyl group which may have a substituent.

[0038] Optionally substituted cyclic groups: The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity. Furthermore, the aliphatic hydrocarbon group may be saturated or unsaturated.

[0039] Ra 01The aromatic hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. The number of carbon atoms in the aromatic hydrocarbon group is preferably 4 to 30, more preferably 5 to 30, even more preferably 5 to 20, and particularly preferably 6 to 15. However, the number of carbon atoms does not include the number of carbon atoms in the substituent. Ra 01 Specific examples of the aromatic ring contained in the aromatic hydrocarbon group in the above formula include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which some of the carbon atoms constituting these aromatic rings are substituted with heteroatoms. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Ra 01 Specific examples of the aromatic hydrocarbon group in the formula (I) include a group in which one hydrogen atom has been removed from the aromatic ring (aryl group: for example, phenyl group, naphthyl group, etc.), and a group in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc.). The number of carbon atoms in the alkylene group (alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

[0040] Ra 01 The cyclic aliphatic hydrocarbon group in the formula (I) includes an aliphatic hydrocarbon group containing a ring in the structure. Examples of aliphatic hydrocarbon groups that contain a ring in their structure include alicyclic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 8 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among these, the polycycloalkane is more preferably a polycycloalkane having a bridged ring polycyclic skeleton, such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane; or a polycycloalkane having a fused ring polycyclic skeleton, such as a cyclic group having a steroid skeleton.

[0041] The linear aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6, and even more preferably 1 to 4. The linear aliphatic hydrocarbon group is preferably a linear alkylene group, and specific examples thereof include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)5-]. The branched aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0042] Also, Ra 01 The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle, etc. Specific examples include lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) described below, -SO2- containing cyclic groups represented by the general formulae (a5-r-1) to (a5-r-4) described below, and other heterocyclic groups represented by the chemical formulae (r-hr-1) to (r-hr-16) described below.

[0043] An optionally substituted chain alkyl group: Ra 01 The chain alkyl group may be either a straight chain or a branched chain. The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decanyl group, an undecyl group, a dodecyl group, a tridecyl group, an isotridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, an isohexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a heneicosyl group, and a docosyl group. The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specific examples include a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0044] An optionally substituted chain alkenyl group: Ra 01 The chain alkenyl group may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5, even more preferably 2 to 4, and particularly preferably 3. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched alkenyl group include a 1-methylvinyl group, a 2-methylvinyl group, a 1-methylpropenyl group, and a 2-methylpropenyl group. Of the chain alkenyl groups mentioned above, linear alkenyl groups are preferred, vinyl groups and propenyl groups are more preferred, and vinyl groups are particularly preferred.

[0045] In the formula (a0-1), Ra 01 The substituent in the hydrocarbon group which may have a substituent may be a monovalent substituent or a divalent substituent. Examples of the monovalent substituent include a carboxy group, a hydroxy group, an amino group, a sulfo group, a halogen atom, a halogenated alkyl group, an alkoxy group, an alkyloxycarbonyl group, and a nitro group. Examples of the divalent substituent include -O-, -C(=O)-O-, -C(=O)-, -OC(=O)-O-, -C(=O)-NH-, -NH-, =N-, -NH-C(=NH)-, -S-, -S(=O)2-, -S(=O)2-O-, etc. H in the divalent substituent may be substituted with a substituent such as an alkyl group or an acyl group.

[0046] In the formula (a0-1), Ya 02 is a single bond or a divalent linking group. Ya 02 The divalent linking group in 01 The divalent linking group is the same as that in the above. 02 is preferably a single bond or a linear or branched aliphatic hydrocarbon group, more preferably a single bond or a linear aliphatic hydrocarbon group, still more preferably a single bond, a methylene group [-CH-] or an ethylene group [-(CH)-], particularly preferably a single bond or a methylene group [-CH-], and most preferably a single bond.

[0047] In the formula (a0-1), Ra 02 is a hydrogen atom, a hydroxy group, or a hydrocarbon group which may have a substituent. Ra 02 The hydrocarbon group which may have a substituent in 01 The same applies to the hydrocarbon group which may have a substituent in the above formula (I).

[0048] In the formula (a0-1), Ar is a benzene ring or a naphthalene ring, and is preferably a benzene ring.

[0049] In the formula (a0-1), Ra 01 and Ra 02 are mutually bonded to form Ra 01 and Ya 02 and the secondary carbon atom to which Ya is bonded.02 And, Ya 02 The carbon atom of Ar to which Ra is bonded 02 may form a ring (hereinafter sometimes referred to as "ring X") with the carbon atom of Ar to which it is bonded. In such a case, ring X and Ar form a fused ring.

[0050] Examples of ring X include an alicyclic hydrocarbon ring which may have a substituent. The alicyclic hydrocarbon ring is preferably an alicyclic hydrocarbon ring having 4 to 20 carbon atoms, more preferably an alicyclic hydrocarbon ring having 5 to 15 carbon atoms, and even more preferably an alicyclic hydrocarbon ring having 5 to 10 carbon atoms. Examples of the alicyclic hydrocarbon ring in ring X include aliphatic rings such as cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cycloundecane, and cyclododecane, and spiroalkanes such as spiro[4.5]decane and spiro[5.5]undecane. Examples of the substituent that the alicyclic hydrocarbon ring may have include an alkyl group having 1 to 5 carbon atoms, a halogen atom, a halogenated alkyl group having 1 to 5 carbon atoms, and a hydroxy group.

[0051] In the formula (a0-1), Ra 01 is a chain hydrocarbon group, and Ra 02 is a hydrogen atom, or Ra 01 and Ra 02 are preferably bonded to each other to form a ring X, and Ra 01 and Ra 02 are more preferably bonded to each other to form ring X.

[0052] In the formula (a0-1), n01 is, as far as valence allows, an integer of 1 to 6, preferably an integer of 1 to 4, more preferably an integer of 1 to 3, even more preferably 1 or 2, and particularly preferably 1.

[0053] The structural unit (a0) is preferably at least one selected from the group consisting of structural units (a0-1-1) represented by general formula (a0-1-1) below and structural units (a0-1-2) represented by general formula (a0-1-2) below, with structural unit (a0-1-2) being more preferred.

[0054] [ka] [In the formula, R 011 and R 021 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. 011 and Ya 021 is a single bond or a divalent linking group. 011 is a linear or branched aliphatic hydrocarbon group. 012 is a single bond or a divalent linking group. 012 is a hydrogen atom or a hydroxy group. Xa is a secondary carbon atom. X is an alicyclic hydrocarbon ring which may have a substituent. Ar is a benzene ring or a naphthalene ring. n011 and n021 are each independently an integer of 1 to 4.]

[0055] In the formula (a0-1-1), R 011 represents R in the formula (a0-1). 01 is the same as: In the formula (a0-1-1), Ya 011 is Ya in the formula (a0-1). 01 and a single bond is preferred. In the formula (a0-1-1), Ya 012 is Ya in the formula (a0-1). 02 Among them, Ya 012 is preferably a single bond or a linear or branched aliphatic hydrocarbon group, more preferably a single bond or a linear aliphatic hydrocarbon group, still more preferably a single bond, a methylene group [-CH-] or an ethylene group [-(CH)-], particularly preferably a single bond or a methylene group [-CH-], and most preferably a single bond.

[0056] In the formula (a0-1-1), Ra011 In the formula (a0-1), the linear or branched aliphatic hydrocarbon group is preferably a group represented by Ra 01 The same applies to the linear or branched aliphatic hydrocarbon group in 011 As the alkyl group, a linear alkyl group having 1 to 10 carbon atoms or a branched alkyl group having 3 to 20 carbon atoms is preferred, a methyl group, an ethyl group, a propyl group, a 1-methylethyl group, a 1-methylpropyl group, or a 2-methylpropyl group is more preferred, and a methyl group is even more preferred.

[0057] In the formula (a0-1-1), Ra 012 is preferably a hydrogen atom. In the formula (a0-1-1), Ar is the same as Ar in the formula (a0-1), and is preferably a benzene ring. In the formula (a0-1-1), n011 is the same as n01 in the formula (a0-1), and is preferably 1 or 2, and more preferably 1.

[0058] In the formula (a0-1-2), R 021 represents R in the formula (a0-1). 01 is the same as: In the formula (a0-1-2), Ya 021 is Ya in the formula (a0-1). 01 and a single bond is preferred.

[0059] In the formula (a0-1-2), the alicyclic hydrocarbon ring for X, which may have a substituent, is the same as the alicyclic hydrocarbon ring for ring X in the formula (a0-1), which may have a substituent, and is preferably cyclopentane, cyclohexane, or cycloheptane, more preferably cyclopentane or cyclohexane.

[0060] In the formula (a0-1-2), Ar is the same as Ar in the formula (a0-1), and is preferably a benzene ring. In the formula (a0-1-2), n021 is the same as n01 in the formula (a0-1), and is preferably 1 or 2, and more preferably 1.

[0061] Specific examples of the structural unit (a0) are shown below. In the following formula, R 01 represents R in the formula (a0-1). 01 is the same as:

[0062] [ka]

[0063] [ka]

[0064] Of the above, the structural unit (a0) is preferably at least one selected from the group consisting of structural units represented by the formulas (a0-u-1), (a0-u-3), (a0-u-9), (a0-u-13), and (a0-u-15).

[0065] The structural unit (a0) contained in the component (A1) may be of one type, or may be of two or more types. The proportion of the structural unit (a0) in the component (A1) is preferably 20 mol % or more, more preferably 25 mol % or more, and even more preferably 30 mol % or more, relative to the total (100 mol %) of all structural units constituting the component (A1), and may be 100 mol % (homopolymer). By ensuring that the proportion of the structural unit (a0) is at least as large as the lower limit of the aforementioned preferred range, lithography properties such as sensitivity and improved roughness are achieved.

[0066] When the component (A1) contains a copolymer having the structural unit (a0), the proportion of the structural unit (a0) in this copolymer is preferably 25 to 70 mol %, more preferably 30 to 65 mol %, and even more preferably 40 to 60 mol %, based on the total (100 mol %) of all structural units constituting this copolymer. By ensuring that the proportion of the structural unit (a0) is at least as large as the lower limit of the aforementioned preferred range, lithography properties such as sensitivity and improved roughness are improved. On the other hand, by ensuring that the proportion is at most the upper limit of the aforementioned preferred range, a balance with other structural units can be achieved, resulting in various favorable lithography properties.

[0067] Other structural units The component (A1) may contain other structural units in addition to the structural unit (a0) described above, as necessary. Examples of other structural units include structural units (a1) containing an acid-decomposable group whose polarity increases upon the action of acid; structural units (a10) represented by the general formula (a10-1) described below; structural units (a2) containing a lactone-containing cyclic group, an —SO—-containing cyclic group, or a carbonate-containing cyclic group; structural units (a3) containing a polar group-containing aliphatic hydrocarbon group; structural units (a4) containing an acid-non-dissociable aliphatic cyclic group; structural units derived from styrene; and structural units derived from styrene derivatives.

[0068] About the structural unit (a1) The structural unit (a1) is a structural unit (excluding those that fall under the category of the aforementioned structural unit (a0)) that contains an acid-decomposable group whose polarity increases when acted upon by an acid. The term "acid-decomposable group" refers to a group having acid decomposability in which at least some of the bonds in the structure of the acid-decomposable group can be cleaved by the action of an acid. Examples of acid-decomposable groups whose polarity increases under the action of an acid include groups that decompose under the action of an acid to generate a polar group. Examples of polar groups include a carboxy group, a hydroxy group, an amino group, a sulfo group (-SO3H), etc. Among these, a polar group containing -OH in the structure (hereinafter sometimes referred to as an "OH-containing polar group") is preferred, a carboxy group or a hydroxy group is more preferred, and a carboxy group is particularly preferred. More specific examples of the acid-decomposable group include groups in which the polar group is protected with an acid-dissociable group (for example, a group in which the hydrogen atom of an OH-containing polar group is protected with an acid-dissociable group).

[0069] Here, the term "acid-dissociable group" refers to either (i) a group having acid dissociability such that the bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group can be cleaved by the action of an acid, or (ii) a group in which a portion of the bond is cleaved by the action of an acid, and then a decarboxylation reaction occurs, thereby cleaving the bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group. The acid-dissociable group constituting the acid-decomposable group must be a group with lower polarity than the polar group generated by dissociation of the acid-dissociable group. Therefore, when the acid-dissociable group dissociates due to the action of an acid, a polar group with higher polarity than the acid-dissociable group is generated, increasing the polarity. As a result, the polarity of the entire component (A1) increases. The increase in polarity relatively changes the solubility in the developer, increasing the solubility when the developer is an alkaline developer and decreasing the solubility when the developer is an organic developer.

[0070] Examples of the acid-dissociable group include those that have been proposed as acid-dissociable groups for base resins used in chemically amplified resist compositions. Specific examples of acid-dissociable groups that have been proposed for use in base resins for chemically amplified resist compositions include the "acetal-type acid-dissociable groups," "tertiary alkyl ester-type acid-dissociable groups," and "tertiary alkyloxycarbonyl acid-dissociable groups," which are described below.

[0071] Acetal type acid dissociable group: Among the polar groups, examples of the acid-dissociable group that protects a carboxy group or a hydroxyl group include acid-dissociable groups represented by the following general formula (a1-r-1) (hereinafter sometimes referred to as "acetal-type acid-dissociable groups").

[0072] [ka] [In the formula, Ra' 1 , Ra' 2 is a hydrogen atom or an alkyl group. 3 is a hydrocarbon group, and Ra' 3 Ra' 1 , Ra' 2may be bonded to any one of the following to form a ring.]

[0073] In formula (a1-r-1), Ra' 1 and Ra' 2 At least one of these is preferably a hydrogen atom, and both are more preferably hydrogen atoms. Ra' 1 or Ra' 2 When is an alkyl group, the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms. Specific examples thereof include linear or branched alkyl groups. More specific examples include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, and neopentyl groups. Methyl and ethyl groups are more preferred, and methyl groups are particularly preferred.

[0074] In formula (a1-r-1), Ra' 3 Examples of the hydrocarbon group include a linear or branched alkyl group, and a cyclic hydrocarbon group. The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, etc. Among these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred.

[0075] The branched alkyl group preferably has 3 to 10 carbon atoms, and more preferably 3 to 5 carbon atoms. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, and is preferably an isopropyl group.

[0076] Ra' 3 When is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. The monocyclic aliphatic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane. The monocycloalkane is preferably a monocycloalkane having 3 to 12 carbon atoms, more preferably a monocycloalkane having 3 to 8 carbon atoms, and even more preferably a monocycloalkane having 5 to 6 carbon atoms. Specific examples of the monocycloalkane include cyclopentane and cyclohexane. The aliphatic hydrocarbon group that is a polycyclic group is preferably a group in which one hydrogen atom has been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0077] Ra' 3 When the cyclic hydrocarbon group is an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, still more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of the aromatic heterocycle include pyridine rings and thiophene rings. Ra' 3Specific examples of the aromatic hydrocarbon group in the formula (I) include a group (aryl group or heteroaryl group) in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle; a group in which one hydrogen atom has been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and a group in which one hydrogen atom of the aromatic hydrocarbon ring or aromatic heterocycle has been substituted with an alkylene group (e.g., arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, and 2-naphthylethyl group). The alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

[0078] Ra' 3 The cyclic hydrocarbon group in may have a substituent. Examples of the substituent include -R P1 , -R P2 -OR P1 , -R P2 -CO-R P1 , -R P2 -CO-OR P1 , -R P2 -O-CO-R P1 , -R P2 -OH, -R P2 -CN or -R P2 -COOH (hereinafter these substituents are collectively referred to as "Ra 05 ") are also examples. where R P1 is a monovalent linear saturated hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. P2 is a single bond, a divalent chain saturated hydrocarbon group having 1 to 10 carbon atoms, a divalent alicyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms. P1 and R P2Some or all of the hydrogen atoms in the chain saturated hydrocarbon group, the alicyclic saturated hydrocarbon group, and the aromatic hydrocarbon group may be substituted with fluorine atoms. The alicyclic hydrocarbon group may have one or more of the above-mentioned substituents, or may have one or more of each of multiple types of the above-mentioned substituents. Examples of the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a decyl group. Examples of the monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms include monocyclic aliphatic saturated hydrocarbon groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group, and a cyclododecyl group; and polycyclic aliphatic saturated hydrocarbon groups such as a bicyclo[2.2.2]octanyl group, a tricyclo[5.2.1.02,6]decanyl group, a tricyclo[3.3.1.13,7]decanyl group, a tetracyclo[6.2.1.13,6.02,7]dodecanyl group, and an adamantyl group. Examples of the monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms include groups in which one hydrogen atom has been removed from an aromatic hydrocarbon ring such as benzene, biphenyl, fluorene, naphthalene, anthracene, or phenanthrene.

[0079] Ra' 3 But Ra' 1 , Ra' 2 When the cyclic group is bonded to any of the above to form a ring, the cyclic group is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

[0080] Tertiary alkyl ester-type acid-labile group: Among the polar groups, examples of the acid-dissociable group that protects the carboxy group include acid-dissociable groups represented by the following general formula (a1-r-2). Among the acid-dissociable groups represented by the following formula (a1-r-2), those constituted by an alkyl group may be referred to as "tertiary alkyl ester-type acid-dissociable groups" hereinafter for convenience.

[0081] [ka] [In the formula, Ra' 4 ~Ra' 6 are each a hydrocarbon group, and Ra' 5 , Ra' 6 may be bonded to each other to form a ring.

[0082] Ra' 4 Examples of the hydrocarbon group include a linear or branched alkyl group, a linear or cyclic alkenyl group, and a cyclic hydrocarbon group. Ra' 4 The linear or branched alkyl group and the cyclic hydrocarbon group (the monocyclic aliphatic hydrocarbon group, the polycyclic aliphatic hydrocarbon group, and the aromatic hydrocarbon group) in 3 The same can be mentioned. Ra' 4 The chain or cyclic alkenyl group in the formula (I) is preferably an alkenyl group having 2 to 10 carbon atoms. Ra' 5 , Ra' 6 The hydrocarbon group of Ra' 3 The same can be mentioned.

[0083] Ra' 5 and Ra' 6 and (a1-r2-3) are preferably substituted or unsubstituted by the alkyl group. On the other hand, Ra' 4 ~Ra' 6 When are not bonded to each other and are independent hydrocarbon groups, preferred examples include groups represented by the following general formula (a1-r2-4).

[0084] [ka] [In formula (a1-r2-1), Ra' 10 represents an alkyl group having 1 to 10 carbon atoms or a group represented by the following general formula (a1-r2-r1): 11 Ra' 10 represents a group that forms an aliphatic cyclic group together with the carbon atom to which Ya is bonded. In formula (a1-r2-2), Ya is a carbon atom. Xa is a group that forms a cyclic hydrocarbon group together with Ya. Some or all of the hydrogen atoms in this cyclic hydrocarbon group may be substituted. Ra 01 ~Ra 03 are each independently a hydrogen atom, a monovalent linear saturated hydrocarbon group having 1 to 10 carbon atoms, or a monovalent cyclic aliphatic saturated hydrocarbon group having 3 to 20 carbon atoms. Some or all of the hydrogen atoms in the linear saturated hydrocarbon group and the cyclic aliphatic saturated hydrocarbon group may be substituted. 01 ~Ra 03 Two or more of these may be bonded to each other to form a cyclic structure. In formula (a1-r2-3), Yaa is a carbon atom. Xaa is a group which forms an aliphatic cyclic group together with Yaa. Ra 04 In formula (a1-r2-4), Ra' is an aromatic hydrocarbon group which may have a substituent. 12 and Ra' 13 are each independently a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms or a hydrogen atom. Some or all of the hydrogen atoms in this chain saturated hydrocarbon group may be substituted. 14 is a hydrocarbon group which may have a substituent. * indicates a bond.]

[0085] [ka] [Wherein, Ya 0 is a quaternary carbon atom. 031 , Ra 032 and Ra 033 are each independently a hydrocarbon group which may have a substituent. 031 , Ra 032 and Ra 033At least one of the groups is a hydrocarbon group having at least one polar group.

[0086] In the above formula (a1-r2-1), Ra' 10 The alkyl group having 1 to 10 carbon atoms is represented by Ra' in the formula (a1-r-1). 3 The groups Ra' listed as examples of the linear or branched alkyl group are preferred. 10 is preferably an alkyl group having 1 to 5 carbon atoms.

[0087] In the formula (a1-r2-r1), Ya 0 is a quaternary carbon atom, i.e., Ya 0 (carbon atom) has four adjacent carbon atoms bonded to it.

[0088] In the formula (a1-r2-r1), Ra 031 , Ra 032 and Ra 033 Each of Ra is independently a hydrocarbon group which may have a substituent. 031 , Ra 032 and Ra 033 The hydrocarbon groups in each of the above may independently be a linear or branched alkyl group, a linear or cyclic alkenyl group, or a cyclic hydrocarbon group.

[0089] Ra 031 , Ra 032 and Ra 033 The linear alkyl group in the formula (I) preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. Of these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred. Ra 031 , Ra 032 and Ra 033The branched alkyl group in the formula (I) preferably has 3 to 10 carbon atoms, more preferably 3 to 5. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, with an isopropyl group being preferred. Ra 031 , Ra 032 and Ra 033 The chain or cyclic alkenyl group in the formula (I) is preferably an alkenyl group having 2 to 10 carbon atoms.

[0090] Ra 031 , Ra 032 and Ra 033 The cyclic hydrocarbon group in may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. The monocyclic aliphatic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane. The monocycloalkane is preferably a monocycloalkane having 3 to 12 carbon atoms, more preferably a monocycloalkane having 3 to 8 carbon atoms, and even more preferably a monocycloalkane having 5 to 6 carbon atoms. Specific examples of the monocycloalkane include cyclopentane and cyclohexane. The aliphatic hydrocarbon group that is a polycyclic group is preferably a group in which one hydrogen atom has been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0091] Ra 031 , Ra 032 and Ra 033The aromatic hydrocarbon group in the formula (I) is a hydrocarbon group having at least one aromatic ring. This aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, even more preferably 6 to 15, and particularly preferably 6 to 12. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of the aromatic heterocycle include pyridine rings and thiophene rings. Specific examples of the aromatic hydrocarbon group include groups in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl groups or heteroaryl groups); groups in which one hydrogen atom has been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and groups in which one hydrogen atom of the aromatic hydrocarbon ring or aromatic heterocycle has been substituted with an alkylene group (e.g., arylalkyl groups such as benzyl, phenethyl, 1-naphthylmethyl, 2-naphthylmethyl, 1-naphthylethyl, and 2-naphthylethyl). The alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle preferably has 1 to 4 carbon atoms, more preferably 1 to 2, and particularly preferably 1.

[0092] The above Ra 031 , Ra 032 and Ra 033 When the hydrocarbon group represented by the formula (I) is substituted, examples of the substituent include a hydroxy group, a carboxy group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, etc.), an alkoxy group (a methoxy group, an ethoxy group, a propoxy group, a butoxy group, etc.), an alkyloxycarbonyl group, etc.

[0093] Among the above, Ra 031 , Ra 032 and Ra 033The hydrocarbon group which may have a substituent is preferably a linear or branched alkyl group which may have a substituent, more preferably a linear alkyl group.

[0094] However, Ra 031 , Ra 032 and Ra 033 At least one of the groups is a hydrocarbon group having at least a polar group. The term "hydrocarbon group having a polar group" includes both a hydrocarbon group in which a methylene group (-CH-) constituting the hydrocarbon group is substituted with a polar group, and a hydrocarbon group in which at least one hydrogen atom constituting the hydrocarbon group is substituted with a polar group. Such a "hydrocarbon group having a polar group" is preferably a functional group represented by the following general formula (a1-p1).

[0095] [ka] [In the formula, Ra 07 represents a divalent hydrocarbon group having 1 to 12 carbon atoms. 08 represents a divalent linking group containing a hetero atom. 06 represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms. p0 is an integer between 1 and 6.

[0096] In the formula (a1-p1), Ra 07 represents a divalent hydrocarbon group having 1 to 12 carbon atoms. Ra 07 has 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, and particularly preferably 1 or 2 carbon atoms. Ra 07 The hydrocarbon group in is preferably a chain or cyclic aliphatic hydrocarbon group, more preferably a chain hydrocarbon group. Ra 07Examples of the alkyl group include linear alkanediyl groups such as ethylene, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, and dodecane-1,12-diyl; branched alkanediyl groups such as cyclobutane-1,3-diyl, cyclopentane-1,3-diyl, cyclohexane-1,4-diyl, and cyclooctane-1,5-diyl; and polycyclic divalent alicyclic hydrocarbon groups such as norbornane-1,4-diyl, norbornane-2,5-diyl, adamantane-1,5-diyl, and adamantane-2,6-diyl. Among the above, an alkanediyl group is preferred, and a linear alkanediyl group is more preferred.

[0097] In the formula (a1-p1), Ra 08 represents a divalent linking group containing a hetero atom. Ra 08 Examples of such groups include -O-, -C(=O)-O-, -C(=O)-, -OC(=O)-O-, -C(=O)-NH-, -NH-, -NH-C(=NH)- (H may be substituted with a substituent such as an alkyl group or an acyl group), -S-, -S(=O)2-, and -S(=O)2-O-. Among these, -O-, -C(=O)-O-, -C(=O)- and -OC(=O)-O- are preferred, and -O- and -C(=O)- are particularly preferred.

[0098] In the formula (a1-p1), Ra 06 represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms. Ra 06has 1 to 12 carbon atoms, and from the viewpoint of solubility in a developer, preferably has 1 to 8 carbon atoms, more preferably has 1 to 5 carbon atoms, even more preferably has 1 to 3 carbon atoms, particularly preferably has 1 or 2 carbon atoms, and most preferably has 1 carbon atom.

[0099] Ra 06 The hydrocarbon group in the formula (I) may be a chain hydrocarbon group, a cyclic hydrocarbon group, or a hydrocarbon group that is a combination of a chain and a cyclic group. Examples of chain hydrocarbon groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, 2-ethylhexyl, n-octyl, n-nonyl, n-decyl, n-undecyl, and n-dodecyl groups.

[0100] The cyclic hydrocarbon group may be an alicyclic hydrocarbon group or an aromatic hydrocarbon group. The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, methylcyclohexyl, dimethylcyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl, adamantyl, 2-alkyladamantan-2-yl, 1-(adamantan-1-yl)alkane-1-yl, norbornyl, methylnorbornyl, and isobornyl. Examples of aromatic hydrocarbon groups include a phenyl group, a naphthyl group, an anthryl group, a p-methylphenyl group, a p-tert-butylphenyl group, a p-adamantylphenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a biphenyl group, a phenanthryl group, a 2,6-diethylphenyl group, and a 2-methyl-6-ethylphenyl group.

[0101] Ra 06From the viewpoint of solubility in a developer, the alkyl group is preferably a chain hydrocarbon group, more preferably a chain alkyl group, and even more preferably a linear alkyl group.

[0102] In the formula (a1-p1), n p0 is an integer of 1 to 6, preferably an integer of 1 to 3, more preferably 1 or 2, and even more preferably 1.

[0103] Specific examples of the hydrocarbon group having at least a polar group are shown below. In the following formulas, * denotes a quaternary carbon atom (Ya 0 ) is the bond that bonds to the

[0104] [ka]

[0105] In the formula (a1-r2-r1), Ra 031 , Ra 032 and Ra 033 The number of hydrocarbon groups having at least a polar group is one or more, but may be determined appropriately taking into consideration the solubility in a developer when forming a resist pattern. For example, 031 , Ra 032 and Ra 033 It is preferable that the number be one or two of the above, and it is particularly preferable that the number be one of the above.

[0106] The hydrocarbon group having at least a polar group may have a substituent other than the polar group, such as a halogen atom (fluorine atom, chlorine atom, bromine atom, etc.) or a halogenated alkyl group having 1 to 5 carbon atoms.

[0107] In formula (a1-r2-1), Ra' 11 (Ra' 10 The aliphatic cyclic group formed together with the carbon atom to which the carbon atom is bonded is represented by Ra' in formula (a1-r-1). 3 The groups mentioned above as the aliphatic hydrocarbon group are preferably monocyclic or polycyclic groups.

[0108] In the formula (a1-r2-2), the cyclic hydrocarbon group formed by Xa together with Ya includes Ra' in the formula (a1-r-1). 3 Examples of such groups include groups in which one or more hydrogen atoms have been further removed from the cyclic monovalent hydrocarbon group (aliphatic hydrocarbon group) shown above. The cyclic hydrocarbon group formed by Xa together with Ya may have a substituent. The substituent may be any of the above-mentioned Ra' 3 Examples of the substituents include the same as those that the cyclic hydrocarbon group in the above may have. In formula (a1-r2-2), Ra 01 ~Ra 03 In the above formula, examples of the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a decyl group. Ra 01 ~Ra 03 In the formula (I), examples of the monovalent aliphatic cyclic saturated hydrocarbon group having 3 to 20 carbon atoms include monocyclic aliphatic saturated hydrocarbon groups such as a cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecyl group, and cyclododecyl group; and polycyclic aliphatic saturated hydrocarbon groups such as a bicyclo[2.2.2]octanyl group, tricyclo[5.2.1.02,6]decanyl group, tricyclo[3.3.1.13,7]decanyl group, tetracyclo[6.2.1.13,6.02,7]dodecanyl group, and adamantyl group. Ra 01 ~Ra 03 Among these, from the viewpoint of ease of synthesis of the monomer compound from which the structural unit (a1) is derived, a hydrogen atom or a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms is preferred, and of these, a hydrogen atom, a methyl group, or an ethyl group is more preferred, with a hydrogen atom being particularly preferred.

[0109] The above Ra 01 ~Ra 03 Examples of the substituents that the chain saturated hydrocarbon group or the aliphatic cyclic saturated hydrocarbon group represented by the formula: 05 The same groups as those shown below can be mentioned.

[0110] Ra 01 ~Ra 03 Examples of groups containing a carbon-carbon double bond resulting from two or more of the above bonding together to form a cyclic structure include a cyclopentenyl group, a cyclohexenyl group, a methylcyclopentenyl group, a methylcyclohexenyl group, a cyclopentylidene-ethenyl group, a cyclohexylidene-ethenyl group, etc. Of these, from the viewpoint of ease of synthesis of the monomer compound from which the structural unit (a1) is derived, a cyclopentenyl group, a cyclohexenyl group, and a cyclopentylidene-ethenyl group are preferred.

[0111] In formula (a1-r2-3), the aliphatic cyclic group formed by Xaa together with Yaa is Ra' in formula (a1-r-1). 3 The groups mentioned above as the aliphatic hydrocarbon group are preferably monocyclic or polycyclic groups. In formula (a1-r2-3), Ra 04 Examples of the aromatic hydrocarbon group in the formula include a group in which one or more hydrogen atoms have been removed from an aromatic hydrocarbon ring having 5 to 30 carbon atoms. 04 is preferably a group in which one or more hydrogen atoms have been removed from an aromatic hydrocarbon ring having 6 to 15 carbon atoms, more preferably a group in which one or more hydrogen atoms have been removed from benzene, naphthalene, anthracene or phenanthrene, still more preferably a group in which one or more hydrogen atoms have been removed from benzene, naphthalene or anthracene, particularly preferably a group in which one or more hydrogen atoms have been removed from benzene or naphthalene, and most preferably a group in which one or more hydrogen atoms have been removed from benzene.

[0112] Ra in formula (a1-r2-3) 04 Examples of the substituent that may be possessed by the group include a methyl group, an ethyl group, a propyl group, a hydroxyl group, a carboxyl group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, etc.), an alkoxy group (a methoxy group, an ethoxy group, a propoxy group, a butoxy group, etc.), an alkyloxycarbonyl group, etc.

[0113] In formula (a1-r2-4), Ra' 12 and Ra' 13are each independently a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms or a hydrogen atom. 12 and Ra' 13 In the above, the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms includes the above Ra 01 ~Ra 03 Examples include the same monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms as in the above. Some or all of the hydrogen atoms in this chain saturated hydrocarbon group may be substituted. Ra' 12 and Ra' 13 Among these, a hydrogen atom or an alkyl group having 1 to 5 carbon atoms is preferred, an alkyl group having 1 to 5 carbon atoms is more preferred, a methyl group or an ethyl group is even more preferred, and a methyl group is particularly preferred. The above Ra' 12 and Ra' 13 When the chain saturated hydrocarbon group represented by the formula: is substituted, examples of the substituent include the above-mentioned Ra 05 The same groups as those shown below can be mentioned.

[0114] In formula (a1-r2-4), Ra' 14 Ra' is a hydrocarbon group which may have a substituent. 14 The hydrocarbon group in the formula (I) includes a linear or branched alkyl group, or a cyclic hydrocarbon group.

[0115] Ra' 14 The linear alkyl group in the formula (I) preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, etc. Among these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred.

[0116] Ra' 14The branched alkyl group in the formula (I) preferably has 3 to 10 carbon atoms, more preferably 3 to 5. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, with an isopropyl group being preferred.

[0117] Ra' 14 When is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. The monocyclic aliphatic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane. The monocycloalkane is preferably a monocycloalkane having 3 to 12 carbon atoms, more preferably a monocycloalkane having 3 to 8 carbon atoms, and even more preferably a monocycloalkane having 5 to 6 carbon atoms. Specific examples of the monocycloalkane include cyclopentane and cyclohexane. The aliphatic hydrocarbon group that is a polycyclic group is preferably a group in which one hydrogen atom has been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0118] Ra' 14 As the aromatic hydrocarbon group in 04 Among them, the aromatic hydrocarbon groups Ra' are the same as those in 14 is preferably a group in which one or more hydrogen atoms have been removed from an aromatic hydrocarbon ring having 6 to 15 carbon atoms, more preferably a group in which one or more hydrogen atoms have been removed from benzene, naphthalene, anthracene, or phenanthrene, still more preferably a group in which one or more hydrogen atoms have been removed from benzene, naphthalene, or anthracene, particularly preferably a group in which one or more hydrogen atoms have been removed from naphthalene or anthracene, and most preferably a group in which one or more hydrogen atoms have been removed from naphthalene. Ra' 14 Examples of the substituent that may be possessed by Ra include 04Examples of the substituents include the same as those that may be possessed by the group.

[0119] Ra' in formula (a1-r2-4) 14 When is a naphthyl group, the position at which it is bonded to the tertiary carbon atom in the formula (a1-r2-4) may be either the 1st or 2nd position of the naphthyl group. Ra' in formula (a1-r2-4) 14 When is an anthryl group, the position at which it is bonded to the tertiary carbon atom in the formula (a1-r2-4) may be any one of the 1st, 2nd, or 9th position of the anthryl group.

[0120] Specific examples of the group represented by the formula (a1-r2-1) are listed below.

[0121] [ka]

[0122] [ka]

[0123] [ka]

[0124] Specific examples of the group represented by the formula (a1-r2-2) are listed below.

[0125] [ka]

[0126] [ka]

[0127] [ka]

[0128] Specific examples of the group represented by the formula (a1-r2-3) are listed below.

[0129] [ka]

[0130] Specific examples of the group represented by the formula (a1-r2-4) are listed below.

[0131] [ka]

[0132] Tertiary alkyloxycarbonyl acid dissociating group: Among the polar groups, examples of the acid-dissociable group that protects the hydroxyl group include acid-dissociable groups represented by the following general formula (a1-r-3) (hereinafter, for convenience, may be referred to as "tertiary alkyloxycarbonyl acid-dissociable group").

[0133] [ka] [In the formula, Ra' 7 ~Ra' 9 are each alkyl groups.

[0134] In formula (a1-r-3), Ra' 7 ~Ra' 9 is preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms. The total number of carbon atoms in each alkyl group is preferably 3 to 7, more preferably 3 to 5, and most preferably 3 to 4.

[0135] Examples of the structural unit (a1) include a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent; a structural unit derived from acrylamide; a structural unit derived from hydroxystyrene or a hydroxystyrene derivative in which at least some of the hydrogen atoms in the hydroxyl groups are protected with a substituent containing the above-mentioned acid-decomposable group; and a structural unit derived from vinylbenzoic acid or a vinylbenzoic acid derivative in which at least some of the hydrogen atoms in -C(═O)-OH are protected with a substituent containing the above-mentioned acid-decomposable group.

[0136] Of the above, preferred structural units (a1) are structural units derived from acrylate esters in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent. Preferred specific examples of the structural unit (a1) include structural units represented by the following general formula (a1-1) or (a1-2).

[0137] [ka] [wherein R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. 1 is a divalent hydrocarbon group which may have an ether bond. a1 is an integer from 0 to 2. 1 is an acid-dissociable group represented by the above general formula (a1-r-1) or (a1-r-2). 1 is n a2 + monovalent hydrocarbon group, n a2 is an integer between 1 and 3, and Ra 2 is an acid-dissociable group represented by the above general formula (a1-r-1) or (a1-r-3).

[0138] In the formula (a1-1), the alkyl group of 1 to 5 carbon atoms represented by R is preferably a linear or branched alkyl group of 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group of 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the alkyl group of 1 to 5 carbon atoms have been substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being particularly preferred. R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and is most preferably a hydrogen atom or a methyl group from the viewpoint of industrial availability.

[0139] In the formula (a1-1), Va 1 The divalent hydrocarbon group in may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0140] Va 1 The aliphatic hydrocarbon group as the divalent hydrocarbon group in may be saturated or unsaturated, and is usually preferably saturated. More specifically, the aliphatic hydrocarbon group may be a straight-chain or branched-chain aliphatic hydrocarbon group, or an aliphatic hydrocarbon group containing a ring in its structure.

[0141] The linear aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specific examples include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)5-]. The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, and even more preferably 2 to 4 carbon atoms. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0142] Examples of the aliphatic hydrocarbon group containing a ring in its structure include an alicyclic hydrocarbon group (a group in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring), a group in which an alicyclic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and a group in which an alicyclic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. Examples of the straight-chain or branched-chain aliphatic hydrocarbon group include the same as the straight-chain aliphatic hydrocarbon group or the branched-chain aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably has 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be polycyclic or monocyclic. The monocyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane is preferably a monocycloalkane having 3 to 12 carbon atoms, more preferably a monocycloalkane having 3 to 8 carbon atoms, and even more preferably a monocycloalkane having 5 to 6 carbon atoms. Specific examples of monocycloalkanes include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0143] Va 1 The aromatic hydrocarbon group as the divalent hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. Such aromatic hydrocarbon groups preferably have 3 to 30 carbon atoms, more preferably 5 to 30, even more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12. However, this number of carbon atoms does not include the number of carbon atoms in the substituents. Specific examples of the aromatic ring contained in the aromatic hydrocarbon group include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic hydrocarbon group include a group in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring (an arylene group); a group in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring (an aryl group) has been substituted with an alkylene group (for example, a group in which one hydrogen atom has been further removed from the aryl group in an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, or a 2-naphthylethyl group). The number of carbon atoms in the alkylene group (the alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

[0144] In the formula (a1-1), Ra 1 is an acid-dissociable group represented by the above formula (a1-r-1) or (a1-r-2).

[0145] In the formula (a1-2), Wa 1 n in a2 The monovalent hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group refers to a hydrocarbon group that does not have aromaticity and may be saturated or unsaturated, but is usually preferably saturated. Examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, aliphatic hydrocarbon groups containing a ring in their structure, and groups that combine linear or branched aliphatic hydrocarbon groups with aliphatic hydrocarbon groups containing a ring in their structure. The n a2 The +1 valence is preferably 2 to 4, more preferably 2 or 3.

[0146] In the formula (a1-2), Ra 2 is an acid-dissociable group represented by the above general formula (a1-r-1) or (a1-r-3).

[0147] Specific examples of the structural unit represented by formula (a1-1) are shown below. In each of the following formulas, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0148]

change

[0149]

change

[0150]

change

[0151]

change

[0152]

change

[0153]

change

[0154]

change

[0155]

change

[0156]

change

[0157]

change

[0158]

change

[0159] Specific examples of the structural unit represented by formula (a1-2) are shown below.

[0160] [ka]

[0161] The structural unit (a1) contained in the component (A1) may be of one type, or may be of two or more types. As the structural unit (a1), a structural unit represented by the above formula (a1-1) is more preferred, as it is more likely to further improve the properties (sensitivity, shape, etc.) in lithography using electron beams or EUV. Among these, as the structural unit (a1), those containing a structural unit represented by the following general formula (a1-1-1) are particularly preferred.

[0162] [ka] [In the formula, Ra 1 " is an acid-dissociable group represented by general formula (a1-r2-1), (a1-r2-3), or (a1-r2-4).

[0163] In the formula (a1-1-1), R, Va 1 and n a1 represents R and Va in the formula (a1-1). 1 and n a1 is the same as: The acid-dissociable group represented by the general formula (a1-r2-1), (a1-r2-3) or (a1-r2-4) has been explained above. Among them, it is preferable to select the acid-dissociable group represented by the general formula (a1-r2-1) because it is suitable for EB or EUV use in that it can enhance reactivity. 10 and the carbon atom to which Ra' is bonded. 11 It is more preferable to select an acid-dissociable group in which the groups form an aliphatic cyclic group.

[0164] The proportion of the structural unit (a1) in the component (A1) is preferably 30 to 75 mol %, more preferably 35 to 70 mol %, and even more preferably 40 to 60 mol %, based on the total (100 mol %) of all structural units constituting the component (A1). By ensuring that the proportion of the structural unit (a1) is at least as large as the lower limit of the aforementioned preferred range, lithography properties such as sensitivity, resolution, and roughness can be improved. On the other hand, by ensuring that the proportion is at most the upper limit of the aforementioned preferred range, a balance with other structural units can be achieved, resulting in various favorable lithography properties.

[0165] About the structural unit (a10) The structural unit (a10) is a structural unit represented by the following general formula (a10-1).

[0166] [ka] [In the formula, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.] x1 is a single bond or a divalent linking group. x1 is (n ax1 +1)valent aromatic hydrocarbon group. ax1 is an integer greater than or equal to 1.]

[0167] In the formula (a10-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. The alkyl group having 1 to 5 carbon atoms for R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms for R is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being particularly preferred. R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the viewpoint of industrial availability, more preferably a hydrogen atom, a methyl group, or a trifluoromethyl group, still more preferably a hydrogen atom or a methyl group, and particularly preferably a methyl group.

[0168] In the formula (a10-1), Ya x1 is a single bond or a divalent linking group. Ya x1 The divalent linking group (a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom) in the formula (a0-1) is described above. 01 This is the same as the explanation for the divalent linking group (a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom) in the above.

[0169] Among the above, Ya x1 is preferably a single bond, an ester bond [-C(=O)-O-, -OC(=O)-], an ether bond (-O-), a linear or branched alkylene group, or a combination thereof, and more preferably a single bond or an ester bond [-C(=O)-O-, -OC(=O)-].

[0170] In the formula (a10-1), Wa x1 is (n ax1 +1)valent aromatic hydrocarbon group. Wa x1 The aromatic hydrocarbon group in ax1Examples of the aromatic ring include a group in which 4n+1) hydrogen atoms have been removed. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, even more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in aromatic heterocycles include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of aromatic heterocycles include pyridine rings and thiophene rings. Also, Wa x1 The aromatic hydrocarbon group in the formula (n) may be an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.). ax1 +1) hydrogen atoms may also be removed. Among the above, Wa x1 As examples, benzene, naphthalene, anthracene, or biphenyl (n ax1 A group in which (n +1) hydrogen atoms have been removed from benzene or naphthalene is preferred. ax1 A group obtained by removing (n +1) hydrogen atoms from benzene is more preferred. ax1 A group in which +1) hydrogen atoms have been removed is more preferred.

[0171] In the formula (a10-1), n ax1 is an integer of 1 or more, preferably an integer of 1 to 10, more preferably an integer of 1 to 5, further preferably 1, 2 or 3, and particularly preferably 1 or 2.

[0172] Specific examples of the structural unit (a10) represented by the formula (a10-1) are shown below. In each of the following formulas, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0173] [ka]

[0174] [ka]

[0175] [ka]

[0176] [ka]

[0177] The structural unit (a10) contained in the component (A1) may be of one type, or may be of two or more types. When the component (A1) contains the structural unit (a10), the proportion of the structural unit (a10) in the component (A1) is preferably 5 to 35 mol %, more preferably 10 to 30 mol %, and even more preferably 15 to 25 mol %, based on the total (100 mol %) of all structural units constituting the component (A1). When the proportion of the structural unit (a10) is at least as large as the lower limit of the above-mentioned preferred range, sensitivity during resist pattern formation tends to be further improved.On the other hand, when the proportion is at most the upper limit of the above-mentioned preferred range, a balance with other structural units can be achieved, and various lithography properties become excellent.

[0178] About the structural unit (a2) The structural unit (a2) is a structural unit containing a lactone-containing cyclic group, an -SO2- containing cyclic group, or a carbonate-containing cyclic group (however, this does not include those that correspond to the structural unit (a0) or the structural unit (a1)). The component (A1) may further contain the structural unit (a2) in addition to the structural unit (a0), or in addition to the structural unit (a0) and the structural unit (a1). The lactone-containing cyclic group, -SO2-containing cyclic group, or carbonate-containing cyclic group of the structural unit (a2) is effective in improving the adhesion of the resist film to the substrate when the component (A1) is used to form a resist film. Furthermore, the presence of the structural unit (a2) results in favorable lithography properties, for example, by appropriately adjusting the acid diffusion length, improving the adhesion of the resist film to the substrate, and appropriately adjusting the solubility during development.

[0179] A "lactone-containing cyclic group" refers to a cyclic group containing a ring (lactone ring) containing -OC(=O)- in its ring skeleton. The lactone ring is counted as the first ring, and a group consisting of only a lactone ring is called a monocyclic group. If a group further contains other ring structures, it is called a polycyclic group regardless of the structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group. The lactone-containing cyclic group in the structural unit (a2) is not particularly limited and any suitable group can be used. Specific examples include groups represented by the following general formulae (a2-r-1) to (a2-r-7).

[0180] [ka] [In the formula, Ra' 21 are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, -COOR", -OC(=O)R", a hydroxyalkyl group, or a cyano group; R" is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or an -SO2- containing cyclic group; A" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom (-O-) or a sulfur atom (-S-), an oxygen atom, or a sulfur atom; n' is an integer of 0 to 2, and m' is 0 or 1.

[0181] In the general formulas (a2-r-1) to (a2-r-7), Ra' 21The alkyl group in the formula (I) is preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group is preferably linear or branched. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, and a hexyl group. Among these, a methyl group or an ethyl group is preferred, and a methyl group is particularly preferred. Ra' 21 The alkoxy group in the formula (1) is preferably an alkoxy group having 1 to 6 carbon atoms. The alkoxy group is preferably linear or branched. Specifically, the alkoxy group in the formula (1) is preferably linear or branched. 21 Examples of the alkyl group include a group in which the alkyl groups mentioned above are linked to an oxygen atom (—O—). Ra' 21 Examples of the halogen atom in include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferred. Ra' 21 The halogenated alkyl group in the formula Ra' is 21 Examples of the halogenated alkyl group include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms. As the halogenated alkyl group, a fluorinated alkyl group is preferred, and a perfluoroalkyl group is particularly preferred.

[0182] Ra' 21 In -COOR" and -OC(=O)R", R" is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or an -SO2- containing cyclic group. The alkyl group in R'' may be linear, branched, or cyclic, and preferably has 1 to 15 carbon atoms. When R″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and is particularly preferably a methyl group or an ethyl group. When R" is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane which may or may not be substituted with a fluorine atom or a fluorinated alkyl group; and groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as a bicycloalkane, tricycloalkane, or tetracycloalkane. More specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; and groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples of the lactone-containing cyclic group in R″ include the same groups as those represented by the general formulae (a2-r-1) to (a2-r-7) above. The carbonate-containing cyclic group in R″ is the same as the carbonate-containing cyclic group described below, and specific examples include groups represented by the general formulae (ax3-r-1) to (ax3-r-3). The -SO2-containing cyclic group in R'' is the same as the -SO2-containing cyclic group described below, and specific examples include groups represented by general formulae (a5-r-1) to (a5-r-4). Ra' 21 The hydroxyalkyl group in the formula (I) preferably has 1 to 6 carbon atoms, and specifically, the hydroxyalkyl group in the formula (I) is preferably the hydroxyalkyl group in the formula (I) 21 and a group in which at least one hydrogen atom of the alkyl group is substituted with a hydroxyl group.

[0183] In the general formulae (a2-r-2), (a2-r-3), and (a2-r-5), the alkylene group having 1 to 5 carbon atoms for A" is preferably a linear or branched alkylene group, and examples thereof include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group. When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include groups in which -O- or -S- is present at the terminal or between carbon atoms of the alkylene group, such as O-CH2-, -CH2-O-CH2-, -S-CH2-, and -CH2-S-CH2-. A" is preferably an alkylene group having 1 to 5 carbon atoms or -O-, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.

[0184] Specific examples of the groups represented by the general formulae (a2-r-1) to (a2-r-7) are listed below.

[0185] [ka]

[0186] [ka]

[0187] The term "-SO2-containing cyclic group" refers to a cyclic group containing a ring containing -SO2- in its ring skeleton, specifically a cyclic group in which the sulfur atom (S) in -SO2- forms part of the ring skeleton of the cyclic group. The ring containing -SO2- in the ring skeleton is counted as the first ring, and if it contains only that ring, it is called a monocyclic group. If it contains other ring structures, it is called a polycyclic group regardless of the structure. The -SO2- containing cyclic group may be a monocyclic group or a polycyclic group. The -SO2- containing cyclic group is preferably a cyclic group containing -O-SO2- in its ring skeleton, i.e., a cyclic group containing a sultone ring in which -OS- in -O-SO2- forms part of the ring skeleton. More specific examples of the —SO2—-containing cyclic group include groups represented by the following general formulae (a5-r-1) to (a5-r-4).

[0188] [ka] [In the formula, Ra' 51 are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, -COOR", -OC(=O)R", a hydroxyalkyl group, or a cyano group; R" is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or an -SO2- containing cyclic group; A" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom, or a sulfur atom; and n' is an integer of 0 to 2.

[0189] In the general formulae (a5-r-1) and (a5-r-2), A" is the same as A" in the general formulae (a2-r-2), (a2-r-3), and (a2-r-5). Ra' 51 The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, -COOR", -OC(=O)R", and hydroxyalkyl group in the general formulae (a2-r-1) to (a2-r-7) are each represented by Ra' 21 Examples of the above include those mentioned in the explanation of the above. Specific examples of the groups represented by general formulae (a5-r-1) to (a5-r-4) are listed below, in which "Ac" represents an acetyl group.

[0190] [ka]

[0191] [ka]

[0192] [ka]

[0193] The term "carbonate-containing cyclic group" refers to a cyclic group containing a ring (carbonate ring) containing -OC(=O)-O- in its ring skeleton. The carbonate ring is counted as the first ring, and when there is only a carbonate ring, it is called a monocyclic group. When there is further ring structure, it is called a polycyclic group regardless of the structure. The carbonate-containing cyclic group may be a monocyclic group or a polycyclic group. The carbonate ring-containing cyclic group is not particularly limited and any one can be used. Specific examples include groups represented by the following general formulae (ax3-r-1) to (ax3-r-3).

[0194] [ka] [In the formula, Ra' x31 are each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, -COOR", -OC(=O)R", a hydroxyalkyl group, or a cyano group; R" is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or an -SO2- containing cyclic group; A" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom, or a sulfur atom; p' is an integer of 0 to 3, and q' is 0 or 1.

[0195] In the general formulae (ax3-r-2) to (ax3-r-3), A" is the same as A" in the general formulae (a2-r-2), (a2-r-3) and (a2-r-5). Ra' 31 The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, -COOR", -OC(=O)R", and hydroxyalkyl group in the general formulae (a2-r-1) to (a2-r-7) are each represented by Ra' 21 Examples of the above are similar to those mentioned in the explanation of the above. Specific examples of the groups represented by the general formulae (ax3-r-1) to (ax3-r-3) are listed below.

[0196] [ka]

[0197] Of the structural units (a2), structural units derived from acrylate esters in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent are particularly preferred. Such a structural unit (a2) is preferably a structural unit represented by the following general formula (a2-1).

[0198] [ka] [In the formula, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.] 21 is a single bond or a divalent linking group. 21 is -O-, -COO-, -CON(R')-, -OCO-, -CONHCO- or -CONHCS-, where R' represents a hydrogen atom or a methyl group. 21 If -O-, Ya 21 does not become -CO-. Ra 21 is a lactone-containing cyclic group, a carbonate-containing cyclic group, or an —SO—-containing cyclic group.

[0199] In the formula (a2-1), R is the same as defined above. R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the viewpoint of industrial availability, a hydrogen atom or a methyl group is particularly preferred.

[0200] In the formula (a2-1), Ya 21 The divalent linking group in is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. Ya 21 The divalent linking group (a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom) in the formula (a0-1) is described above. 01This is the same as the explanation for the divalent linking group (a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom) in the above.

[0201] Among the above, Ya 21 is preferably a single bond, an ester bond [—C(═O)—O—], an ether bond (—O—), a linear or branched alkylene group, or a combination thereof.

[0202] In the above formula (a2-1), Ra 21 is a lactone-containing cyclic group, an —SO 2 —-containing cyclic group, or a carbonate-containing cyclic group. Ra 21 Suitable examples of the lactone-containing cyclic group, the -SO2- containing cyclic group, and the carbonate-containing cyclic group in the formula (a2-r-1), (a2-r-7), (a5-r-1), (a5-r-4), and (ax3-r-1), respectively, are the groups represented by the general formulas (ax3-r-3). Among these, lactone-containing cyclic groups or -SO2-containing cyclic groups are preferred, and groups represented by the general formulas (a2-r-1), (a2-r-2), (a2-r-6), and (a5-r-1) are more preferred. Specifically, groups represented by the chemical formulas (r-lc-1-1) to (r-lc-1-7), (r-lc-2-1) to (r-lc-2-18), (r-lc-6-1), (r-sl-1-1), and (r-sl-1-18) are more preferred.

[0203] The structural unit (a2) contained in the component (A1) may be of one type, or may be of two or more types. When the component (A1) contains the structural unit (a2), the proportion of the structural unit (a2) relative to the total (100 mol%) of all structural units constituting the component (A1) is preferably 1 to 25 mol%, more preferably 2 to 20 mol%, and even more preferably 5 to 15 mol%. When the proportion of the structural unit (a2) is at least as great as the preferred lower limit, the effects achieved by including the structural unit (a2) can be fully obtained due to the effects described above. When the proportion of the structural unit (a2) is at most the upper limit, a balance with other structural units can be achieved, and various lithography properties become favorable.

[0204] About the structural unit (a3) The structural unit (a3) is a structural unit containing a polar group-containing aliphatic hydrocarbon group (excluding those that fall under the structural unit (a1) or the structural unit (a2)). By including the structural unit (a3) in the component (A1), the hydrophilicity of the component (A) is enhanced, contributing to improved resolution. In addition, the acid diffusion length can be appropriately adjusted.

[0205] Examples of the polar group include a hydroxyl group, a cyano group, a carboxyl group, and a hydroxyalkyl group in which some of the hydrogen atoms of an alkyl group have been substituted with fluorine atoms, with a hydroxyl group being particularly preferred. Examples of aliphatic hydrocarbon groups include linear or branched hydrocarbon groups (preferably alkylene groups) having 1 to 10 carbon atoms, and cyclic aliphatic hydrocarbon groups (cyclic groups). The cyclic group may be a monocyclic group or a polycyclic group, and can be appropriately selected from the many groups proposed for use in resins for resist compositions for ArF excimer lasers.

[0206] When the cyclic group is a monocyclic group, it more preferably has 3 to 10 carbon atoms. Among these, structural units derived from acrylate esters containing an aliphatic monocyclic group containing a hydroxyl group, a cyano group, a carboxy group, or a hydroxyalkyl group in which some of the alkyl group's hydrogen atoms are substituted with fluorine atoms are more preferred. Examples of such monocyclic groups include groups in which two or more hydrogen atoms have been removed from a monocycloalkane. Specific examples include groups in which two or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane, cyclohexane, or cyclooctane. Among these monocyclic groups, groups in which two or more hydrogen atoms have been removed from cyclopentane and groups in which two or more hydrogen atoms have been removed from cyclohexane are industrially preferred.

[0207] When the cyclic group is a polycyclic group, the polycyclic group preferably has 7 to 30 carbon atoms. Among these, structural units derived from acrylate esters containing an aliphatic polycyclic group containing a hydroxyl group, a cyano group, a carboxy group, or a hydroxyalkyl group in which some of the alkyl group's hydrogen atoms are substituted with fluorine atoms are more preferred. Examples of such polycyclic groups include groups in which two or more hydrogen atoms have been removed from bicycloalkanes, tricycloalkanes, tetracycloalkanes, etc. Specific examples include groups in which two or more hydrogen atoms have been removed from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, groups in which two or more hydrogen atoms have been removed from adamantane, groups in which two or more hydrogen atoms have been removed from norbornane, and groups in which two or more hydrogen atoms have been removed from tetracyclododecane are industrially preferred.

[0208] There are no particular limitations on the structural unit (a3), and any structural unit can be used as long as it contains a polar group-containing aliphatic hydrocarbon group. The structural unit (a3) is preferably a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, and which contains a polar group-containing aliphatic hydrocarbon group. When the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a linear or branched hydrocarbon group having 1 to 10 carbon atoms, the structural unit (a3) is preferably a structural unit derived from a hydroxyethyl ester of acrylic acid. Furthermore, when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a polycyclic group, preferred examples of the structural unit (a3) include structural units represented by the following formulae (a3-1), (a3-2), and (a3-3); and when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a monocyclic group, preferred examples of the structural unit (a3) include structural units represented by formula (a3-4).

[0209] [ka] [In the formula, R is the same as defined above, j is an integer of 1 to 3, k is an integer of 1 to 3, t' is an integer of 1 to 3, l is an integer of 0 to 5, and s is an integer of 1 to 3.]

[0210] In formula (a3-1), j is preferably 1 or 2, and more preferably 1. When j is 2, the hydroxyl groups are preferably bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, the hydroxyl group is preferably bonded to the 3rd position of the adamantyl group. j is preferably 1, and it is particularly preferred that the hydroxyl group is bonded to the 3-position of the adamantyl group.

[0211] In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5- or 6-position of the norbornyl group.

[0212] In formula (a3-3), t' is preferably 1. l is preferably 1. s is preferably 1. In these, a 2-norbornyl group or a 3-norbornyl group is preferably bonded to the terminal of the carboxyl group of the acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5- or 6-position of the norbornyl group.

[0213] In formula (a3-4), t' is preferably 1 or 2. l is preferably 0 or 1. s is preferably 1. The fluorinated alkyl alcohol is preferably bonded to the 3- or 5-position of the cyclohexyl group.

[0214] The structural unit (a3) contained in the component (A1) may be of one type, or may be of two or more types. When the component (A1) contains the structural unit (a3), the proportion of the structural unit (a3) in the component (A1) is preferably 1 to 25 mol %, more preferably 2 to 20 mol %, and even more preferably 5 to 15 mol %, relative to the total (100 mol %) of all structural units constituting the component (A1). When the proportion of the structural unit (a3) is at least as large as the lower limit of the aforementioned preferred range, the effects that can be achieved by having the structural unit (a3) can be fully obtained due to the effects described above. On the other hand, when the proportion of the structural unit (a3) is no more than the upper limit of the aforementioned preferred range, a balance with other structural units can be achieved, and various lithography properties become favorable.

[0215] About the structural unit (a4) The structural unit (a4) is a structural unit containing an acid-non-dissociable aliphatic cyclic group. By including the structural unit (a4) in the component (A1), the dry etching resistance of the formed resist pattern is improved. Furthermore, the hydrophobicity of the component (A) is enhanced. The improved hydrophobicity contributes to improvements in resolution, resist pattern shape, and the like, particularly in solvent development processes. The “acid-non-dissociable cyclic group” within the structural unit (a4) is a cyclic group that, when acid is generated in the resist composition upon exposure (for example, when acid is generated from a structural unit that generates acid upon exposure, or from the component (B) described below), does not dissociate even when acted upon by the acid, and remains intact within the structural unit.

[0216] The structural unit (a4) is preferably, for example, a structural unit derived from an acrylate ester that contains an acid-non-dissociable aliphatic cyclic group. The cyclic group can be any of the many conventionally known resin components used in resist compositions for ArF excimer lasers, KrF excimer lasers (preferably ArF excimer lasers), and the like. The cyclic group is preferably at least one selected from the group consisting of a tricyclodecyl group, an adamantyl group, a tetracyclododecyl group, an isobornyl group, and a norbornyl group, in view of industrial availability, etc. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.

[0217] Specific examples of the structural unit (a4) include structural units represented by the following general formulas (a4-1) to (a4-7). In each of the following formulas, R αrepresents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0218] [ka]

[0219] The structural unit (a4) contained in the component (A1) may be of one type, or may be of two or more types. When the component (A1) contains the structural unit (a4), the proportion of the structural unit (a4) in the component (A1) is preferably 1 to 25 mol %, more preferably 2 to 20 mol %, and even more preferably 5 to 15 mol %, based on the total (100 mol %) of all structural units constituting the component (A1). When the proportion of the structural unit (a4) is at least as large as the lower limit of the aforementioned preferred range, the effects of having the structural unit (a4) can be fully obtained. On the other hand, when the proportion is no more than the upper limit of the aforementioned preferred range, a balance with other structural units can be achieved, and various lithography properties become favorable.

[0220] Regarding structural units derived from styrene and structural units derived from styrene derivatives (hereinafter collectively referred to as "structural units (st)") The term "styrene" is intended to encompass styrene and styrene in which the hydrogen atom at the α-position is substituted with a substituent such as an alkyl group, a halogenated alkyl group, etc. Examples of the alkyl group as the substituent include alkyl groups having 1 to 5 carbon atoms, and examples of the halogenated alkyl group as the substituent include halogenated alkyl groups having 1 to 5 carbon atoms. Examples of the "styrene derivative" include styrene in which the hydrogen atom at the α-position may be substituted with a substituent and a substituent is bonded to the benzene ring of the styrene. Unless otherwise specified, the α-position (α-position carbon atom) refers to the carbon atom to which the benzene ring is bonded. The terms "structural unit derived from styrene" and "structural unit derived from a styrene derivative" refer to a structural unit formed by cleavage of the ethylenic double bond of styrene or a styrene derivative. The structural unit (st) contained in the component (A1) may be of one type, or may be of two or more types. When the component (A1) contains the structural unit (st), the proportion of the structural unit (st) relative to the total (100 mol%) of all structural units constituting the component (A1) is preferably 1 to 30 mol%, and more preferably 3 to 20 mol%.

[0221] The component (A1) contained in the resist composition may use either a single type of compound, or a combination of two or more types of compounds. In the resist composition of this embodiment, the component (A1) can be a polymeric compound having a repeating structure of the structural unit (a0). Preferred examples of the component (A1) include polymeric compounds having a repeating structure of the structural unit (a0) and the structural unit (a1). Specifically, suitable examples of the component (A1) include polymeric compounds having a repeating structure of the structural unit (a0) and the structural unit (a1), and polymeric compounds having a repeating structure of the structural unit (a0), the structural unit (a1), and the structural unit (a10).

[0222] The component (A1) can be produced by dissolving the monomers that derive the respective structural units in a polymerization solvent, and then adding a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate (e.g., V-601) to the solution and polymerizing the resulting mixture. Alternatively, the component (A1) can be produced by dissolving a monomer that derives the structural unit (a0) and, if necessary, a monomer that derives a structural unit other than the structural unit (a0) in a polymerization solvent, adding the above-mentioned radical polymerization initiator to the solution to polymerize, and then carrying out a deprotection reaction. During polymerization, a chain transfer agent such as HS-CH2-CH2-CH2-C(CF3)2-OH may be used in combination to introduce a -C(CF3)2-OH group to the terminal. Copolymers incorporating hydroxyalkyl groups in which some of the alkyl group's hydrogen atoms have been substituted with fluorine atoms are effective in reducing development defects and LER (line edge roughness: unevenness on the line sidewalls).

[0223] The weight average molecular weight (Mw) of the component (A1) (based on polystyrene standards measured by gel permeation chromatography (GPC)) is not particularly limited, but is preferably 1,000 to 50,000, more preferably 2,000 to 30,000, and even more preferably 3,000 to 20,000. When the Mw of the component (A1) is no more than the upper limit of the aforementioned preferred range, the compound exhibits sufficient solubility in a resist solvent for use as a resist. On the other hand, when the Mw is at least the lower limit of the aforementioned preferred range, the compound exhibits good dry etching resistance and favorable cross-sectional shape of the resist pattern. The dispersity (Mw / Mn) of the component (A1) is not particularly limited, but is preferably from 1.0 to 4.0, more preferably from 1.0 to 3.0, and particularly preferably from 1.0 to 2.0, where Mn represents the number average molecular weight.

[0224] Base ingredients other than component (A1) The resist composition of this embodiment may also use, as the component (A), a base component that does not fall under the category of the component (A1), and whose solubility in a developer changes due to the action of an acid. The base component that does not fall under the category of the component (A1) is not particularly limited and can be arbitrarily selected from the many base components that are conventionally known for use in chemically amplified resist compositions, and can be a single polymeric compound or a low molecular weight compound, or a combination of two or more polymeric compounds or low molecular weight compounds.

[0225] The amount of the component (A) in the resist composition of this embodiment may be adjusted depending on factors such as the thickness of the resist film to be formed.

[0226] <Photodegradable base (D0)> The resist composition of this embodiment contains, in addition to the component (A1), a photodegradable base (component (D0)) that controls the diffusion of acid generated upon exposure. The component (D0) has a conjugate acid with an acid dissociation constant (pKa) of 4.0 or less.

[0227] Here, "pKa" refers to the acid dissociation constant, which is generally used as an indicator of the acid strength of a target substance. The pKa value of the conjugate acid of component (D0) can be determined by measurement using a conventional method. Alternatively, the pKa value of the conjugate acid of component (D0) can be calculated by simulation using known software such as "ACD / Labs" (trade name, manufactured by Advanced Chemistry Development).

[0228] The pKa of the conjugate acid of component (D0) (calculated using the software "ACD / Labs") is 4.0 or less, preferably 3.8 or less, more preferably 0.1 to 3.5, and even more preferably 0.3 to 3.3. When the pKa of the conjugate acid of component (D0) is equal to or less than the above-mentioned upper limit, a better pattern shape is likely to be obtained during resist pattern formation. On the other hand, when the pKa of the conjugate acid of component (D0) is equal to or greater than the above-mentioned lower limit of the preferred range, sensitivity and resolution are likely to be improved.

[0229] A preferred example of the component (D0) is a compound represented by the following general formula (d0-1).

[0230] [ka] [In the formula, R d0 is a substituent. q0 is an integer of 0 to 3. n0 is an integer of 1 or more. p0 is an integer of 0 or more. When p0 is 2 or more, a plurality of R d0 may be the same or different, provided that n0+p0≦(q0×2)+5; m is an integer of 1 or more; m+is an m-valent organic cation.

[0231] The anion portion of the compound represented by general formula (d0-1) In the formula (d0-1), R d0 is a substituent. Examples of the substituent include a hydrocarbon group, an alkoxy group, an acyl group, and a hydroxyalkyl group.

[0232] Examples of the hydrocarbon group as a substituent include a linear or branched alkyl group, an aliphatic cyclic hydrocarbon group, and an aromatic hydrocarbon group.

[0233] The linear or branched alkyl group is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, and a pentyl group. The aliphatic cyclic hydrocarbon group is preferably an aliphatic cyclic hydrocarbon group having 3 to 6 carbon atoms, and specific examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. The aromatic hydrocarbon group is preferably an aromatic hydrocarbon group having 6 to 30 carbon atoms, and specific examples thereof include groups in which one hydrogen atom has been removed from an aromatic hydrocarbon ring such as benzene, biphenyl, fluorene, naphthalene, anthracene, phenanthrene, etc. Among these, a group in which one hydrogen atom has been removed from benzene (phenyl group) is more preferred.

[0234] The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, and specific examples thereof include a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, a tert-butoxy group, a pentyloxy group, etc. Among these, a methoxy group is more preferred. The acyl group as the substituent is preferably an acyl group having 1 to 3 carbon atoms, and specific examples thereof include a formyl group, an acetyl group, and a propionyl group.

[0235] The hydroxyalkyl group as a substituent is preferably a hydroxyalkyl group having 1 to 5 carbon atoms, and specific examples thereof include a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group, and a hydroxypentyl group.

[0236] In the formula (d0-1), q0 is an integer of 0 to 3. That is, in the anion moiety in formula (d0-1), when q0 is 0, the structure is a benzene structure, when q0 is 1, the structure is a naphthalene structure, when q0 is 2, the structure is an anthracene structure, and when q0 is 3, the structure is a tetracene structure. q0 is preferably 0 or 1, and more preferably 0. In the formula (d0-1), n0 is an integer of 1 or more, preferably an integer of 1 to 3, more preferably 1 or 2, and even more preferably 2. In the formula (d0-1), p0 is an integer of 0 or more. When p0 is 2 or more, a plurality of R d0 may be the same or different. p0 is preferably an integer of 0 to 3, more preferably an integer of 0 to 2, further preferably 0 or 1, and particularly preferably 0.

[0237] In the formula (d0-1), n0+p0≦(q0×2)+5. When q0 is an integer of 0 to 3, that is, in the benzene structure, naphthalene structure, anthracene structure, or tetracene structure, a carboxylate group (—C(═O)O - ) are each independently substituted with the above substituents (R d0 ) or a hydroxy group, provided that the anion moiety in formula (d0-1) has at least one hydroxy group. In addition, in the above benzene structure, naphthalene structure, anthracene structure, or tetracene structure, a carboxylate group (-C(=O)O - ), the above-mentioned substituent (R d0 ) and the substitution position of the hydroxy group are not particularly limited.

[0238] Preferred examples of the anion moiety in the compound represented by general formula (d0-1) are shown below. The acid dissociation constant (pKa) of the conjugate acid of the compound corresponding to the anion moiety is also shown.

[0239] [ka]

[0240] [ka]

[0241] [ka]

[0242] [ka]

[0243] [ka]

[0244] [ka]

[0245] The cation moiety in the compound represented by general formula (d0-1) In the formula (d0-1), m is an integer of 1 or more, and M m+ is an m-valent organic cation. M m+ In the above formula, examples of the m-valent organic cation include m-valent onium cations, and among these, sulfonium cations and iodonium cations are preferred.

[0246] Preferred cationic moieties ((M m+ ) 1 / m) includes organic cations represented by the following general formulas (ca-1) to (ca-5), respectively.

[0247] [ka] [In the formula, R 201 ~R 207 , and R 211 ~R 212 R each independently represents an aryl group, an alkyl group, or an alkenyl group which may have a substituent. 201 ~R 203 , R 206 ~R 207 , R 211 ~R 212 may be bonded to each other to form a ring together with the sulfur atom in the formula. 208 ~R 209 R each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. 210 is an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted -SO2- containing cyclic group. 201 represents -C(=O)- or -C(=O)-O-. Y 201 each independently represents an arylene group, an alkylene group, or an alkenylene group. x is 1 or 2. W 201 represents a (x+1)-valent linking group.

[0248] In the above general formulas (ca-1) to (ca-5), R 201 ~R 207 , and R 211 ~R 212 The aryl group in the formula (I) includes an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. R 201 ~R 207 , and R 211 ~R 212 The alkyl group in is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. R 201 ~R 207, and R 211 ~R 212 The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms. R 201 ~R 207 , and R 210 ~R 212 Examples of the substituent that may be possessed by the group include an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and groups represented by the following general formulae (ca-r-1) to (ca-r-7).

[0249] [ka] [In the formula, R' 201 are each independently a hydrogen atom, a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent.

[0250] Optionally substituted cyclic groups: The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity. Furthermore, the aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

[0251] R' 201 The aromatic hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, even more preferably 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and most preferably 6 to 10 carbon atoms. However, the number of carbon atoms does not include the number of carbon atoms in the substituent. R' 201Specific examples of the aromatic ring contained in the aromatic hydrocarbon group in the above formula include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which some of the carbon atoms constituting these aromatic rings are substituted with heteroatoms. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. R' 201 Specific examples of the aromatic hydrocarbon group in include a group in which one hydrogen atom has been removed from the aromatic ring (aryl group: for example, phenyl group, naphthyl group, etc.), and a group in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc.). The alkylene group (the alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

[0252] R' 201 The cyclic aliphatic hydrocarbon group in the formula (I) is an aliphatic hydrocarbon group containing a ring in the structure. Examples of aliphatic hydrocarbon groups that contain a ring in their structure include alicyclic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among these, the polycycloalkane is more preferably a polycycloalkane having a bridged ring polycyclic skeleton, such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane; or a polycycloalkane having a fused ring polycyclic skeleton, such as a cyclic group having a steroid skeleton.

[0253] Among them, R' 201 The cyclic aliphatic hydrocarbon group in is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane or a polycycloalkane, more preferably a group in which one hydrogen atom has been removed from a polycycloalkane, particularly preferably an adamantyl group or a norbornyl group, and most preferably an adamantyl group.

[0254] The linear or branched aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specific examples include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)5-]. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0255] Also, R' 201 The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle. Specific examples include the lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) above, the —SO—-containing cyclic groups represented by the general formulae (a5-r-1) to (a5-r-4) above, and other heterocyclic groups represented by the chemical formulae (r-hr-1) to (r-hr-16) above.

[0256] R' 201 Examples of the substituent in the cyclic group include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group. The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group. As the halogen atom as a substituent, a fluorine atom is preferred. Examples of halogenated alkyl groups as substituents include alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, n-butyl, and tert-butyl groups, in which some or all of the hydrogen atoms have been substituted with the above-mentioned halogen atoms. The carbonyl group as a substituent is a group that substitutes a methylene group (-CH2-) that constitutes a cyclic hydrocarbon group.

[0257] An optionally substituted chain alkyl group: R' 201 The chain alkyl group may be either a straight chain or a branched chain. The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specific examples include a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0258] An optionally substituted chain alkenyl group: R' 201 The chain alkenyl group may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms, even more preferably 2 to 4 carbon atoms, and particularly preferably 3 carbon atoms. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched alkenyl group include a 1-methylvinyl group, a 2-methylvinyl group, a 1-methylpropenyl group, and a 2-methylpropenyl group. Of the chain alkenyl groups mentioned above, linear alkenyl groups are preferred, vinyl groups and propenyl groups are more preferred, and vinyl groups are particularly preferred.

[0259] R' 201 Examples of the substituent in the chain alkyl or alkenyl group include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, the above-mentioned R' 201 Examples of the cyclic groups include the cyclic groups shown in the formula:

[0260] R' 201 In addition to those mentioned above, the optionally substituted cyclic group, the optionally substituted chain alkyl group, or the optionally substituted chain alkenyl group also includes the same as the acid-dissociable group represented by formula (a1-r-2) above as the optionally substituted cyclic group or the optionally substituted chain alkyl group.

[0261] Among them, R' 201 is preferably a cyclic group which may have a substituent, and more preferably a cyclic hydrocarbon group which may have a substituent. More specifically, for example, a phenyl group, a naphthyl group, a group in which one or more hydrogen atoms have been removed from a polycycloalkane, a lactone-containing cyclic group represented by each of the general formulae (a2-r-1) to (a2-r-7), or an —SO2- containing cyclic group represented by each of the general formulae (a5-r-1) to (a5-r-4) is preferred.

[0262] In the above general formulas (ca-1) to (ca-5), R 201 ~R 203 , R 206 ~R 207 , R 211 ~R 212 When they are bonded to each other to form a ring together with the sulfur atom in the formula, they may not contain a heteroatom such as a sulfur atom, an oxygen atom, or a nitrogen atom, or a carbonyl group, -SO-, -SO2-, -SO3-, -COO-, -CONH-, or -N(R N )-(the R Nis an alkyl group having 1 to 5 carbon atoms.) The ring formed is preferably a 3- to 10-membered ring, including the sulfur atom, and particularly preferably a 5- to 7-membered ring, inclusive of the sulfur atom. Specific examples of the ring formed include a thiophene ring, a thiazole ring, a benzothiophene ring, a thianthrene ring, a benzothiophene ring, a dibenzothiophene ring, a 9H-thioxanthene ring, a thioxanthone ring, a thianthrene ring, a phenoxathiin ring, a tetrahydrothiophenium ring, and a tetrahydrothiopyranium ring.

[0263] R 208 ~R 209 each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and when they are alkyl groups, they may be bonded to each other to form a ring.

[0264] R 210 is an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted -SO2- containing cyclic group. R 210 The aryl group in the formula (I) includes an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. R 210 The alkyl group in is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. R 210 The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms. R 210 As the -SO2- containing cyclic group which may have a substituent in the formula (a5-r-1), an "-SO2- containing polycyclic group" is preferred, and a group represented by the above general formula (a5-r-1) is more preferred.

[0265] Y 201 each independently represents an arylene group, an alkylene group, or an alkenylene group. Y 201The arylene group in the above formula (I) is the same as that in the above formula (I). x0 Examples of the aromatic hydrocarbon group in the above formula include groups in which one hydrogen atom has been removed from the aryl groups exemplified above. Y 201 The alkylene group and alkenylene group in the above R' 201 Examples of the chain alkyl group and the chain alkenyl group include groups in which one hydrogen atom has been removed from the groups exemplified above as the chain alkyl group and the chain alkenyl group.

[0266] In the formula (ca-4), x is 1 or 2. W 201 is an (x+1)-valent, i.e., a divalent or trivalent linking group. W 201 The divalent linking group in the formula (a0-1) is preferably a divalent hydrocarbon group which may have a substituent. 01 Examples of the divalent hydrocarbon groups include those shown below, which may have a substituent. 201 The divalent linking group in may be linear, branched, or cyclic, and is preferably cyclic. Among them, a group in which two carbonyl groups are combined at both ends of an arylene group is preferred. Examples of the arylene group include a phenylene group and a naphthylene group, and a phenylene group is particularly preferred. W 201 The trivalent linking group in 201 Examples of the divalent linking group include a group in which one hydrogen atom has been removed from the divalent linking group shown in the formula (1), and a group in which the divalent linking group is further bonded to the divalent linking group shown in the formula (1). 201 The trivalent linking group in the formula (I) is preferably a group in which two carbonyl groups are bonded to an arylene group.

[0267] Of the above, the cation moiety of the compound represented by general formula (d0-1) is preferably a cation represented by the following general formula (ca-d0-1).

[0268] [ka] [In the formula, R d01is an aryl group having a fluorine atom or an aryl group having a fluorinated alkyl group. d02 and R d03 are each independently an aryl group which may have a substituent, or are mutually bonded to form a ring together with the sulfur atom in the formula.

[0269] In the above formula (ca-d0-1), R d01 is an aryl group having a fluorine atom or an aryl group having a fluorinated alkyl group. The aryl group is R 201 ~R 203 The fluorinated alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group, in which some or all of the hydrogen atoms have been substituted with fluorine atoms, and more preferably a trifluoromethyl group.

[0270] R d02 and R d03 R are each independently an aryl group which may have a substituent, or are mutually bonded to form a ring together with the sulfur atom in the formula. b1 ~R b3 The aryl group in the formula (ca-1) is R 201 ~R 203 The same applies to the aryl group in the above.

[0271] R b2 and R b3 The ring formed by bonding together with the sulfur atom in the formula includes R 201 ~R 203 The aryl groups in the formula (I) are bonded to each other to form a ring together with the sulfur atom in the formula (I).

[0272] Suitable cations represented by the formula (ca-1) are shown below.

[0273] [ka]

[0274] [ka]

[0275] [ka] [In the formula, g2 and g3 represent the number of repeating units, g2 is an integer of 0 to 20, and g3 is an integer of 0 to 20.]

[0276] [ka]

[0277] [ka]

[0278] [ka] [In the formula, R” 201 is a hydrogen atom or a substituent, and the substituent is the same as R 201 ~R 207 , and R 210 ~R 212 The substituents are the same as those exemplified as the substituents that may be possessed by the group

[0279] [ka]

[0280] [ka]

[0281] [ka]

[0282] Specific examples of suitable cations represented by the formula (ca-2) include diphenyliodonium cation, bis(4-tert-butylphenyl)iodonium cation, and the like.

[0283] Specific examples of suitable cations represented by the formula (ca-3) include cations represented by the following formulas (ca-3-1) to (ca-3-6).

[0284] [ka]

[0285] Specific examples of suitable cations represented by the formula (ca-4) include cations represented by the following formulas (ca-4-1) to (ca-4-2).

[0286] [ka]

[0287] Specific examples of suitable cations represented by the formula (ca-5) include cations represented by the following general formulas (ca-5-1) to (ca-5-3).

[0288] [ka]

[0289] In the resist composition of this embodiment, the cation moiety of the compound represented by general formula (d0-1) is preferably a cation represented by general formula (ca-1) among the above. Specifically, cations represented by any of the above chemical formulas (ca-1-1) to (ca-1-93), (ca-1-100) to (ca-1-114) are preferred, cations represented by any of the above chemical formulas (ca-1-100) to (ca-1-114) are more preferred, cations represented by any of the above chemical formulas (ca-1-100) to (ca-1-112) are even more preferred, and cations represented by any of the above chemical formulas (ca-1-100) to (ca-1-103) are particularly preferred.

[0290] In the resist composition of this embodiment, the component (D0) is preferably a compound represented by the following general formula (d0-1-0).

[0291] [ka] [In the formula, R d01 is an aryl group having a fluorine atom or an aryl group having a fluorinated alkyl group. d02 and R d03 R are each independently an aryl group which may have a substituent, or are mutually bonded to form a ring together with the sulfur atom in the formula. d0 is a substituent. q0 is an integer of 0 to 3. n0 is an integer of 1 or more. p0 is an integer of 0 or more. When p0 is 2 or more, a plurality of R d0 may be the same or different, provided that n0 + p0 ≦ (q0 × 2) + 5.

[0292] In the general formula (d0-1-0), R d01 , R d02 and R d03 The explanation for R in the above general formula (ca-d0-1) d01 , R d02 and R d03 This is the same as the explanation for In the general formula (d0-1-0), R d0 , q0, n0 and p0 are explained in detail in the above general formula (d0-1) R d0 , q0, n0 and p0.

[0293] Specific examples of preferred components (D0) are shown below, along with the acid dissociation constant (pKa) of the conjugate acid of each compound.

[0294] [ka]

[0295] [ka]

[0296] In the resist composition of this embodiment, the component (D0) may be used alone, or in combination of two or more different compounds. In the resist composition of this embodiment, the amount of the component (D0) relative to 100 parts by mass of the component (A) is preferably 1 to 50 parts by mass, more preferably 3 to 50 parts by mass, even more preferably 3 to 20 parts by mass, and particularly preferably 3 to 10 parts by mass. By ensuring that the amount of the component (D0) falls within the above-mentioned preferred range, the solubility of the exposed areas of the resist film in a developer is enhanced, thereby further improving sensitivity and resolution.

[0297] <Other ingredients> The resist composition of this embodiment may further contain other components in addition to the above-mentioned components (A1) and (D0). Examples of other components include the following components (B), (D) (excluding component (D0)), (E), (F), and (S).

[0298] <Acid generator component (B)> The resist composition of this embodiment may further contain an acid generator component (B) (hereafter referred to as “component (B)”) that generates acid upon exposure. There are no particular restrictions on the component (B), and any of the acid generators that have been proposed as acid generators for chemically amplified resist compositions can be used. Examples of such acid generators include onium salt-based acid generators such as iodonium salts and sulfonium salts, oxime sulfonate-based acid generators, diazomethane-based acid generators such as bisalkyl or bisaryl sulfonyl diazomethanes and poly(bissulfonyl) diazomethanes, nitrobenzyl sulfonate-based acid generators, imino sulfonate-based acid generators, and disulfone-based acid generators.

[0299] Examples of the onium salt acid generator include a compound represented by the following general formula (b-1) (hereinafter also referred to as "component (b-1)"), a compound represented by general formula (b-2) (hereinafter also referred to as "component (b-2)"), or a compound represented by general formula (b-3) (hereinafter also referred to as "component (b-3)").

[0300] [ka] [In the formula, R 101 and R 104 ~R 108 R are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. 104 and R 105 R may be bonded to each other to form a ring structure. 102 is a fluorinated alkyl group having 1 to 5 carbon atoms or a fluorine atom. 101 is a divalent linking group containing an oxygen atom or a single bond. 101 ~V 103 are each independently a single bond, an alkylene group, or a fluorinated alkylene group. 101 ~L 102 are each independently a single bond or an oxygen atom. 103 ~L 105 are each independently a single bond, —CO— or —SO2—; m is an integer of 1 or more; and M' m+ is an m-valent onium cation.

[0301] {anion part} Anion in component (b-1) In formula (b-1), R 101 represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent.

[0302] Optionally substituted cyclic groups: The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity. Furthermore, the aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

[0303] R 101 The aromatic hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. The number of carbon atoms in the aromatic hydrocarbon group is preferably 3 to 30, more preferably 5 to 30, even more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 10. However, the number of carbon atoms does not include the number of carbon atoms in the substituent. R 101 Specific examples of the aromatic ring contained in the aromatic hydrocarbon group in the above formula include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which some of the carbon atoms constituting these aromatic rings are substituted with heteroatoms. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. R 101 Specific examples of the aromatic hydrocarbon group in the formula (I) include a group in which one hydrogen atom has been removed from the aromatic ring (aryl group: for example, phenyl group, naphthyl group, etc.), and a group in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc.). The number of carbon atoms in the alkylene group (alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

[0304] R101 The cyclic aliphatic hydrocarbon group in the formula (I) is an aliphatic hydrocarbon group containing a ring in the structure. Examples of aliphatic hydrocarbon groups that contain a ring in their structure include alicyclic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among these, the polycycloalkane is more preferably a polycycloalkane having a bridged ring polycyclic skeleton, such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane; or a polycycloalkane having a fused ring polycyclic skeleton, such as a cyclic group having a steroid skeleton.

[0305] Among them, R 101 The cyclic aliphatic hydrocarbon group in is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane or a polycycloalkane, more preferably a group in which one hydrogen atom has been removed from a polycycloalkane, particularly preferably an adamantyl group or a norbornyl group, and most preferably an adamantyl group.

[0306] The linear aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6, even more preferably 1 to 4, and most preferably 1 to 3. The linear aliphatic hydrocarbon group is preferably a linear alkylene group, and specific examples thereof include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)5-]. The branched aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, even more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0307] Also, R 101 The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle. Specific examples include lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7), -SO2- containing cyclic groups represented by the general formulae (a5-r-1) to (a5-r-4), and heterocyclic groups represented by the following chemical formulae (r-hr-1) to (r-hr-16). * in the formula represents Y in formula (b-1). 101 represents a bond bonded to

[0308] [ka]

[0309] R 101 Examples of the substituent in the cyclic group include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group. The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group. Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferred. Examples of halogenated alkyl groups as substituents include alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, n-butyl, and tert-butyl groups, in which some or all of the hydrogen atoms have been substituted with the above-mentioned halogen atoms. The carbonyl group as a substituent is a group that substitutes a methylene group (-CH2-) that constitutes a cyclic hydrocarbon group.

[0310] R 101 The cyclic hydrocarbon group in may be a fused ring group containing a fused ring in which an aliphatic hydrocarbon ring and an aromatic ring are fused. Examples of the fused ring include a polycycloalkane having a polycyclic skeleton of a bridged ring system to which one or more aromatic rings are fused. Specific examples of the bridged ring system polycycloalkane include bicycloalkanes such as bicyclo[2.2.1]heptane (norbornane) and bicyclo[2.2.2]octane. The fused ring group is preferably a group containing a fused ring in which two or three aromatic rings are fused to a bicycloalkane, and more preferably a group containing a fused ring in which two or three aromatic rings are fused to a bicyclo[2.2.2]octane.101 Specific examples of the fused cyclic group in the formula (b-1) include those represented by the following formulas (r-br-1) to (r-br-2). 101 represents a bond bonded to

[0311] [ka]

[0312] R 101 Examples of the substituent that the fused cyclic group in the formula (I) may have include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an aromatic hydrocarbon group, and an alicyclic hydrocarbon group. The alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent of the fused cyclic group are the same as those described above in R 101 Examples of the substituents for the cyclic group in the formula (I) include the same as those listed above. Examples of the aromatic hydrocarbon group as the substituent of the fused ring group include a group in which one hydrogen atom has been removed from an aromatic ring (aryl group: for example, a phenyl group, a naphthyl group, etc.), a group in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, a 2-naphthylethyl group, etc.), and heterocyclic groups represented by the above formulas (r-hr-1) to (r-hr-6). Examples of the alicyclic hydrocarbon group as a substituent of the fused cyclic group include groups in which one hydrogen atom has been removed from a monocycloalkane such as cyclopentane or cyclohexane; groups in which one hydrogen atom has been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane or tetracyclododecane; lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) above; —SO2- containing cyclic groups represented by the general formulae (a5-r-1) to (a5-r-4) above; and heterocyclic groups represented by the formulae (r-hr-7) to (r-hr-16) above.

[0313] A chain alkyl group which may have a substituent: R 101 The chain alkyl group may be either a straight chain or a branched chain. The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specific examples include a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0314] An optionally substituted chain alkenyl group: R 101 The chain alkenyl group may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5, even more preferably 2 to 4, and particularly preferably 3. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched alkenyl group include a 1-methylvinyl group, a 2-methylvinyl group, a 1-methylpropenyl group, and a 2-methylpropenyl group. Of the chain alkenyl groups mentioned above, linear alkenyl groups are preferred, vinyl groups and propenyl groups are more preferred, and vinyl groups are particularly preferred.

[0315] R 101 Examples of the substituent in the chain alkyl or alkenyl group include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, and the above-mentioned R 101 Examples of the cyclic groups include the cyclic groups shown in the formula:

[0316] Among the above, R 101is preferably a cyclic group which may have a substituent, and more preferably a cyclic hydrocarbon group which may have a substituent. More specifically, preferred are a phenyl group, a naphthyl group, a group in which one or more hydrogen atoms have been removed from a polycycloalkane, a lactone-containing cyclic group represented by each of the general formulae (a2-r-1) to (a2-r-7), and an —SO2- containing cyclic group represented by each of the general formulae (a5-r-1) to (a5-r-4).

[0317] In formula (b-1), Y 101 is a single bond or a divalent linking group containing an oxygen atom. Y 101 is a divalent linking group containing an oxygen atom, 101 may contain atoms other than oxygen atoms. Examples of atoms other than oxygen atoms include carbon atoms, hydrogen atoms, sulfur atoms, and nitrogen atoms. Examples of divalent linking groups containing an oxygen atom include non-hydrocarbon oxygen-containing linking groups such as an oxygen atom (ether bond: -O-), an ester bond (-C(=O)-O-), an oxycarbonyl group (-O-C(=O)-), an amide bond (-C(=O)-NH-), a carbonyl group (-C(=O)-), and a carbonate bond (-O-C(=O)-O-); and combinations of such non-hydrocarbon oxygen-containing linking groups with alkylene groups. A sulfonyl group (-SO2-) may be further linked to these combinations. Examples of such divalent linking groups containing an oxygen atom include linking groups represented by the following general formulae (y-al-1) to (y-al-7).

[0318] [ka] [In the formula, V' 101 is a single bond or an alkylene group having 1 to 5 carbon atoms, and V' 102 is a divalent saturated hydrocarbon group having 1 to 30 carbon atoms.

[0319] V' 102The divalent saturated hydrocarbon group in is preferably an alkylene group having 1 to 30 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, and even more preferably an alkylene group having 1 to 5 carbon atoms.

[0320] V' 101 and V' 102 The alkylene group in may be a straight-chain alkylene group or a branched-chain alkylene group, and is preferably a straight-chain alkylene group. V' 101 and V' 102 Specific examples of the alkylene group in the formula (I) include a methylene group [-CH2-]; alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; an ethylene group [-CH2CH2-]; -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, and -CH(CH2CH3)CH2 -, etc.; a trimethylene group (n-propylene group) [-CH2CH2CH2-]; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; a tetramethylene group [-CH2CH2CH2CH2-]; alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-; and a pentamethylene group [-CH2CH2CH2CH2CH2-]. Also, V' 101 or V' 102 In the formula (a1-r-1), some of the methylene groups in the alkylene group may be substituted with a divalent aliphatic cyclic group having 5 to 10 carbon atoms. The aliphatic cyclic group is represented by Ra' in the formula (a1-r-1). 3 A divalent group obtained by removing one more hydrogen atom from a cyclic aliphatic hydrocarbon group (a monocyclic aliphatic hydrocarbon group or a polycyclic aliphatic hydrocarbon group) of the above is preferred, and a cyclohexylene group, a 1,5-adamantylene group or a 2,6-adamantylene group is more preferred.

[0321] Y 101As the linking group, a divalent linking group containing an ester bond or a divalent linking group containing an ether bond is preferred, and the linking groups represented by the above formulas (y-al-1) to (y-al-5) are more preferred.

[0322] In formula (b-1), V 101 is a single bond, an alkylene group, or a fluorinated alkylene group. 101 The alkylene group and fluorinated alkylene group in the formula (V) preferably have 1 to 4 carbon atoms. 101 The fluorinated alkylene group in 101 In particular, groups in which some or all of the hydrogen atoms of the alkylene group in the formula (I) are substituted with fluorine atoms are preferred. 101 is preferably a single bond or a fluorinated alkylene group having 1 to 4 carbon atoms.

[0323] In formula (b-1), R 102 is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. 102 is preferably a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms, and more preferably a fluorine atom.

[0324] Specific examples of the anion moiety represented by the formula (b-1) include, for example, Y 101 When Y is a single bond, examples of the anion include a fluorinated alkylsulfonate anion such as a trifluoromethanesulfonate anion or a perfluorobutanesulfonate anion; 101 When is a divalent linking group containing an oxygen atom, examples of the anions include those represented by any of the following formulae (an-1) to (an-3).

[0325] [ka] [In the formula, R” 101 R" is an aliphatic cyclic group which may have a substituent, a monovalent heterocyclic group represented by each of the above chemical formulas (r-hr-1) to (r-hr-6), a fused cyclic group represented by the above formula (r-br-1) or (r-br-2), or a chain alkyl group which may have a substituent.102 R" is an aliphatic cyclic group which may have a substituent, a fused cyclic group represented by the formula (r-br-1) or (r-br-2) above, a lactone-containing cyclic group represented by each of the general formulae (a2-r-1), (a2-r-3) to (a2-r-7) above, or an -SO2- containing cyclic group represented by each of the general formulae (a5-r-1) to (a5-r-4) above. 103 V" is an aromatic cyclic group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain alkenyl group which may have a substituent. 101 is a single bond, an alkylene group having 1 to 4 carbon atoms, or a fluorinated alkylene group having 1 to 4 carbon atoms. 102 is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms; each v" is independently an integer of 0 to 3, each q" is independently an integer of 0 to 20, and n" is 0 or 1.

[0326] R” 101 , R” 102 and R” 103 The aliphatic cyclic group which may have a substituent is represented by R 101 The substituent is preferably a group exemplified as the cyclic aliphatic hydrocarbon group in the formula (b-1). 101 Examples of the substituents that may be substituted on the cyclic aliphatic hydrocarbon group in the above formula (1) include the same as those that may be substituted on the cyclic aliphatic hydrocarbon group in the above formula (1).

[0327] R” 103 The aromatic cyclic group which may have a substituent in the formula (b-1) is R 101 The substituent is preferably a group exemplified as the aromatic hydrocarbon group in the cyclic hydrocarbon group in the formula (b-1). 101 Examples of the substituents that may substitute the aromatic hydrocarbon group in the above formula (1) include the same as those in the above formula (1).

[0328] R” 101 The chain alkyl group which may have a substituent in the formula (b-1) is R 101 The alkyl group is preferably one of the groups exemplified as the chain alkyl group in the above formula. R” 103The chain alkenyl group which may have a substituent is R 101 Preferably, it is a group exemplified as the chain alkenyl group in the above formula.

[0329] Anion in component (b-2) In formula (b-2), R 104 , R 105 are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each is represented by R 101 However, R 104 , R 105 may be bonded to each other to form a ring. R 104 , R 105 is preferably a chain alkyl group which may have a substituent, more preferably a linear or branched alkyl group, or a linear or branched fluorinated alkyl group. The chain alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 7 carbon atoms, and even more preferably 1 to 3 carbon atoms. 104 , R 105 The number of carbon atoms in the chain alkyl group of R is preferably as small as possible within the above range of carbon atoms, for reasons such as good solubility in resist solvents. 104 , R 105 In the chain alkyl group, the greater the number of hydrogen atoms substituted with fluorine atoms, the stronger the acid strength and the improved transparency to high-energy light of 250 nm or less and electron beams, which is preferable. The proportion of fluorine atoms in the chain alkyl group, i.e., the fluorination rate, is preferably 70 to 100%, more preferably 90 to 100%, and most preferably a perfluoroalkyl group in which all hydrogen atoms are substituted with fluorine atoms. In formula (b-2), V 102 , V 103 are each independently a single bond, an alkylene group, or a fluorinated alkylene group, and each represents V in formula (b-1). 101 The same can be mentioned. In formula (b-2), L 101 , L 102 are each independently a single bond or an oxygen atom.

[0330] Anion in component (b-3) In formula (b-3), R 106 ~R 108 are each independently a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each is represented by R 101 The same can be mentioned. In formula (b-3), L 103 ~L 105 are each independently a single bond, —CO— or —SO2—.

[0331] Among the above, the anion moiety of component (B) is preferably the anion in component (b-1). Among these, anions represented by any of the above general formulas (an-1) to (an-3) are more preferred, anions represented by either general formula (an-1) or (an-2) are even more preferred, and anions represented by general formula (an-2) are particularly preferred.

[0332] {cation part} In the formula (b-1), formula (b-2), and formula (b-3), M' m+ represents an m-valent onium cation. Among these, sulfonium cation and iodonium cation are preferred. m is an integer of 1 or more.

[0333] Preferred cationic moieties ((M' m+ ) 1 / m ) includes organic cations represented by the above general formulas (ca-1) to (ca-5), respectively, and the cation represented by general formula (ca-1) is preferred.

[0334] In the resist composition of this embodiment, the component (B) may be used either as a single type, or in combination of two or more types. When the resist composition contains the component (B), the amount of the component (B) in the resist composition is preferably less than 50 parts by mass, more preferably 5 to 40 parts by mass, and even more preferably 10 to 30 parts by mass, per 100 parts by mass of the component (A1). By ensuring that the amount of component (B) falls within the above-mentioned preferred range, sufficient pattern formation is achieved. Furthermore, when the components of the resist composition are dissolved in an organic solvent, a homogeneous solution is easily obtained, and the storage stability of the resist composition is also favorable.

[0335] <Base component (D)> The resist composition of this embodiment may further contain a base component (component (D)) other than component (D0) that traps acid generated upon exposure (i.e., controls the diffusion of acid). The component (D) acts as a quencher (acid diffusion controller) that traps acid generated in the resist composition upon exposure. Examples of the component (D) include a photodegradable base (D1) (hereinafter referred to as "component (D1)") that decomposes upon exposure and loses its acid diffusion controllability, and a nitrogen-containing organic compound (D2) (hereinafter referred to as "component (D2)") that does not fall under the category of component (D1). Among these, the photodegradable base (component (D1)) is preferred because it is likely to enhance all of the properties of high sensitivity, reduced roughness, and suppressed occurrence of coating defects.

[0336] Regarding component (D1) By using a resist composition that contains the component (D1), the contrast between exposed and unexposed areas of the resist film can be further improved when forming a resist pattern. The component (D1) is not particularly limited as long as it decomposes upon exposure to light and loses its acid diffusion controllability, and is preferably one or more compounds selected from the group consisting of a compound represented by the following general formula (d1-1) (hereinafter referred to as "component (d1-1)"), a compound represented by the following general formula (d1-2) (hereinafter referred to as "component (d1-2)"), and a compound represented by the following general formula (d1-3) (hereinafter referred to as "component (d1-3)"). The components (d1-1) to (d1-3) do not act as quenchers in the exposed areas of the resist film because they decompose and lose their acid diffusion control properties (basicity), but act as quenchers in the unexposed areas of the resist film.

[0337] [ka] [In the formula, Rd 1 ~Rd 4 is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. 2 In this case, no fluorine atom is bonded to the carbon atom adjacent to the S atom. 1 is a single bond or a divalent linking group; m is an integer of 1 or more; M m+ are each independently an m-valent organic cation.

[0338] {(d1-1) component} Anion part In formula (d1-1), Rd 1 represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each represents R' in the above general formulae (ca-r-1) to (ca-r-7). 201 The same can be mentioned. Among these, Rd 1 As the substituent, an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain-like alkyl group which may have a substituent is preferred. Substituents which these groups may have include a hydroxyl group, an oxo group, an alkyl group, an aryl group, a fluorine atom, a fluorinated alkyl group, a lactone-containing cyclic group represented by each of the above general formulas (a2-r-1) to (a2-r-7), an ether bond, an ester bond, or a combination thereof. When an ether bond or an ester bond is contained as a substituent, it may be connected via an alkylene group, and in this case, the substituent is preferably a linking group represented by each of the above formulas (y-al-1) to (y-al-5). Suitable examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, and a polycyclic structure containing a bicyclooctane skeleton (a polycyclic structure consisting of a bicyclooctane skeleton and another ring structure). The aliphatic cyclic group is more preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. The chain alkyl group preferably has 1 to 10 carbon atoms, and specific examples thereof include straight-chain alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group; and branched-chain alkyl groups such as a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0339] When the chain-like alkyl group is a fluorinated alkyl group having a fluorine atom or a fluorinated alkyl group as a substituent, the number of carbon atoms in the fluorinated alkyl group is preferably 1 to 11, more preferably 1 to 8, and even more preferably 1 to 4. The fluorinated alkyl group may contain atoms other than fluorine atoms. Examples of atoms other than fluorine atoms include oxygen atoms, sulfur atoms, and nitrogen atoms.

[0340] Preferred examples of the anion moiety of the component (d1-1) are shown below.

[0341] [ka]

[0342] Cation part In formula (d1-1), M m+ is an m-valent organic cation. M m+Suitable examples of the organic cation include the same cations represented by the general formulae (ca-1) to (ca-5), respectively, and the cation represented by the general formula (ca-1) is more preferred. The component (d1-1) may be used alone or in combination of two or more.

[0343] {(d1-2) component} Anion part In formula (d1-2), Rd 2 represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each represents R' in the above general formulae (ca-r-1) to (ca-r-7). 201 The same can be mentioned. However, Rd 2 In this case, the carbon atom adjacent to the S atom is not bonded to a fluorine atom (is not fluorinated), which makes the anion of component (d1-2) an appropriately weak acid anion, thereby improving the quenching ability of component (D). Road 2 is preferably a chain alkyl group which may have a substituent, or an aliphatic cyclic group which may have a substituent. The chain alkyl group preferably has 1 to 10 carbon atoms, and more preferably 3 to 10. The aliphatic cyclic group is more preferably a group (which may have a substituent) in which one or more hydrogen atoms have been removed from adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, or the like; or a group in which one or more hydrogen atoms have been removed from camphor, or the like. Road 2 The hydrocarbon group may have a substituent, and the substituent may be Rd 1 Examples of the substituents include the same as those that may be contained in the hydrocarbon group (aromatic hydrocarbon group, aliphatic cyclic group, chain alkyl group) in the above.

[0344] Preferred examples of the anion moiety of the component (d1-2) are shown below.

[0345] [ka]

[0346] Cation part In formula (d1-2), M m+ is an m-valent organic cation, and M in the formula (d1-1) m+ is the same as: The component (d1-2) may be used alone or in combination of two or more.

[0347] {(d1-3) component} Anion part In formula (d1-3), Rd 3 represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each of R' in the above general formulae (ca-r-1) to (ca-r-7) 201 The Rd is preferably a fluorine atom-containing cyclic group, a chain alkyl group, or a chain alkenyl group. Among these, a fluorinated alkyl group is preferred, and the Rd 1 The same fluorinated alkyl groups as those mentioned above are more preferred.

[0348] In formula (d1-3), Rd 4 represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and each represents R' in the above general formulae (ca-r-1) to (ca-r-7). 201 The same can be mentioned. Among these, alkyl groups, alkoxy groups, alkenyl groups and cyclic groups which may have a substituent are preferred. Road 4 The alkyl group in Rd is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. 4A portion of the hydrogen atoms of the alkyl group may be substituted with a hydroxyl group, a cyano group, or the like. Road 4 The alkoxy group in is preferably an alkoxy group having 1 to 5 carbon atoms, and specific examples of the alkoxy group having 1 to 5 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group. Of these, a methoxy group and an ethoxy group are preferred.

[0349] Road 4 The alkenyl group in R' 201 Examples include the same alkenyl groups as those in the above, and a vinyl group, a propenyl group (allyl group), a 1-methylpropenyl group, or a 2-methylpropenyl group is preferred. These groups may further have an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms as a substituent.

[0350] Road 4 The cyclic group in the formula (I) is the same as the R' 201 Examples of the cyclic group include the same as the cyclic group in the above, and preferred are alicyclic groups obtained by removing one or more hydrogen atoms from a cycloalkane such as cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane, or aromatic groups such as a phenyl group or a naphthyl group. 4 When Rd is an alicyclic group, the resist composition dissolves well in an organic solvent, resulting in excellent lithography properties. 4 When is an aromatic group, in lithography using EUV or the like as an exposure light source, the resist composition exhibits excellent light absorption efficiency, and exhibits favorable sensitivity and lithography properties.

[0351] In formula (d1-3), Yd 1 is a single bond or a divalent linking group. Yd 1 The divalent linking group in is not particularly limited, but examples thereof include a divalent hydrocarbon group (aliphatic hydrocarbon group, aromatic hydrocarbon group) which may have a substituent, and a divalent linking group containing a hetero atom. 01Examples of the divalent linking group include the same divalent hydrocarbon groups which may have a substituent and divalent linking groups containing a hetero atom as those mentioned in the description of the divalent linking group in the above. Yd 1 is preferably a carbonyl group, an ester bond, an amide bond, an alkylene group, or a combination thereof. The alkylene group is more preferably a linear or branched alkylene group, and further preferably a methylene group or an ethylene group.

[0352] Preferred examples of the anion moiety of the component (d1-3) are shown below.

[0353] [ka]

[0354] [ka]

[0355] Cation part In formula (d1-3), M m+ is an m-valent organic cation, and M in the formula (d1-1) m+ is the same as: The component (d1-3) may be used alone or in combination of two or more.

[0356] The component (D1) may be any one of the components (d1-1) to (d1-3) above, or a combination of two or more of them. When the resist composition contains the component (D1), the amount of the component (D1) within the resist composition is preferably 0.5 to 20 parts by mass, and more preferably 1 to 15 parts by mass, per 100 parts by mass of the component (A1). When the amount of the component (D1) is at least as large as the preferred lower limit, particularly good lithography properties and resist pattern shape are likely to be obtained, while when it is at most the upper limit, good sensitivity can be maintained and excellent throughput can be achieved.

[0357] Manufacturing method of component (D1): The method for producing the components (d1-1) and (d1-2) is not particularly limited, and they can be produced by known methods. The method for producing component (d1-3) is not particularly limited, and it can be produced, for example, in a manner similar to that described in US2012-0149916.

[0358] Regarding component (D2) The component (D) may contain a nitrogen-containing organic compound component (hereinafter referred to as "component (D2)") that does not fall under the category of the component (D1) described above. The component (D2) is not particularly limited as long as it acts as an acid diffusion controller and does not fall under the category of component (D1), and any known component may be used. Among these, aliphatic amines are preferred, and among these, secondary aliphatic amines and tertiary aliphatic amines are particularly preferred. The aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms. Examples of aliphatic amines include amines in which at least one hydrogen atom of ammonia NH3 has been substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms (alkylamines or alkyl alcohol amines), and cyclic amines. Specific examples of alkylamines and alkyl alcoholamines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, and n-decylamine; dialkylamines such as diethylamine, di-n-propylamine, di-n-heptylamine, di-n-octylamine, and dicyclohexylamine; trialkylamines such as trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, and tri-n-dodecylamine; and alkyl alcoholamines such as diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine, and tri-n-octanolamine. Among these, trialkylamines having 5 to 10 carbon atoms are more preferred, and tri-n-pentylamine or tri-n-octylamine is particularly preferred.

[0359] Examples of cyclic amines include heterocyclic compounds containing a nitrogen atom as a heteroatom. The heterocyclic compounds may be monocyclic (aliphatic monocyclic amines) or polycyclic (aliphatic polycyclic amines). Specific examples of the aliphatic monocyclic amine include piperidine and piperazine. The aliphatic polycyclic amine preferably has 6 to 10 carbon atoms, and specific examples thereof include 1,5-diazabicyclo[4.3.0]-5-nonene, 1,8-diazabicyclo[5.4.0]-7-undecene, hexamethylenetetramine, and 1,4-diazabicyclo[2.2.2]octane.

[0360] Other aliphatic amines include tris(2-methoxymethoxyethyl)amine, tris{2-(2-methoxyethoxy)ethyl}amine, tris{2-(2-methoxyethoxymethoxy)ethyl}amine, tris{2-(1-methoxyethoxy)ethyl}amine, tris{2-(1-ethoxyethoxy)ethyl}amine, tris{2-(1-ethoxypropoxy)ethyl}amine, tris[2-{2-(2-hydroxyethoxy)ethoxy}ethyl]amine, and triethanolamine triacetate, with triethanolamine triacetate being preferred.

[0361] Furthermore, an aromatic amine may be used as the component (D2). Examples of aromatic amines include 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, tribenzylamine, 2,6-diisopropylaniline, and N-tert-butoxycarbonylpyrrolidine.

[0362] The component (D2) may be used alone or in combination of two or more. When the resist composition contains the component (D2), the amount of the component (D2) within the resist composition is typically within a range from 0.01 to 5 parts by mass per 100 parts by mass of the component (A1). By ensuring this range, the resist pattern shape and stability over time during storage can be improved.

[0363] <<At least one compound (E) selected from the group consisting of organic carboxylic acids, phosphorus oxoacids, and derivatives thereof>> The resist composition of this embodiment may contain, as an optional component, at least one compound (E) selected from the group consisting of organic carboxylic acids, and phosphorus oxo acids and derivatives thereof (hereafter referred to as "component (E)") for the purposes of preventing sensitivity degradation and improving the resist pattern shape and stability over time after exposure. Suitable organic carboxylic acids include, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, and salicylic acid. Examples of phosphorus oxoacids include phosphoric acid, phosphonic acid, and phosphinic acid, with phosphonic acid being particularly preferred. Examples of derivatives of phosphorus oxoacids include esters in which the hydrogen atoms of the above oxoacids are substituted with hydrocarbon groups, and examples of the hydrocarbon groups include alkyl groups having 1 to 5 carbon atoms and aryl groups having 6 to 15 carbon atoms. Examples of the derivatives of phosphoric acid include phosphoric acid esters such as di-n-butyl phosphoric acid ester and diphenyl phosphoric acid ester. Examples of the derivatives of phosphonic acid include phosphonic acid esters such as dimethyl phosphonate, di-n-butyl phosphonate, phenylphosphonic acid, diphenyl phosphonate, and dibenzyl phosphonate. Derivatives of phosphinic acid include phosphinic acid esters and phenylphosphinic acid. In the resist composition of this embodiment, the component (E) may be used either as a single type, or in combination of two or more types. When the resist composition contains the component (E), the amount of the component (E) is typically within a range from 0.01 to 5 parts by mass per 100 parts by mass of the component (A1).

[0364] <Fluorine additive component (F)> The resist composition of this embodiment may contain a fluorine additive component (hereafter referred to as “component (F)”) in order to impart water repellency to the resist film or to improve lithography properties. As the component (F), for example, the fluorine-containing polymer compounds described in JP-A Nos. 2010-002870, 2010-032994, 2010-277043, 2011-13569, and 2011-128226 can be used. More specifically, the component (F) may be a polymer having a structural unit (f1) represented by the following general formula (f1-1): This polymer is preferably a polymer (homopolymer) consisting solely of the structural unit (f1) represented by the following formula (f1-1); a copolymer of the structural unit (f1) with the structural unit (a1); or a copolymer of the structural unit (f1) with a structural unit derived from acrylic acid or methacrylic acid and the structural unit (a1). Here, the structural unit (a1) copolymerized with the structural unit (f1) is preferably a structural unit derived from 1-ethyl-1-cyclooctyl(meth)acrylate or a structural unit derived from 1-methyl-1-adamantyl(meth)acrylate.

[0365] [ka] [wherein R is the same as defined above, and Rf 102 and Rf 103 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; Rf 102 and Rf 103 may be the same or different. 1 is an integer from 0 to 5, and Rf 101 is an organic group containing a fluorine atom.

[0366] In formula (f1-1), R bonded to the carbon atom at the α-position is the same as defined above. R is preferably a hydrogen atom or a methyl group. In formula (f1-1), Rf 102 and Rf 103 The halogen atom in Rf is preferably a fluorine atom. 102 and Rf 103 Examples of the alkyl group having 1 to 5 carbon atoms for R include the same alkyl groups having 1 to 5 carbon atoms as those for R, and a methyl group or an ethyl group is preferred. 102 and Rf 103Specific examples of the halogenated alkyl group having 1 to 5 carbon atoms include groups in which some or all of the hydrogen atoms of an alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. As the halogen atom, a fluorine atom is preferred. Among these, Rf 102 and Rf 103 is preferably a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 5 carbon atoms, and more preferably a hydrogen atom, a fluorine atom, a methyl group, or an ethyl group. In formula (f1-1), nf 1 is an integer of 0 to 5, preferably an integer of 0 to 3, and more preferably 1 or 2.

[0367] In formula (f1-1), Rf 101 is an organic group containing a fluorine atom, and is preferably a hydrocarbon group containing a fluorine atom. The fluorine atom-containing hydrocarbon group may be linear, branched, or cyclic, and preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and particularly preferably 1 to 10 carbon atoms. Furthermore, in the fluorine atom-containing hydrocarbon group, preferably 25% or more of the hydrogen atoms in the hydrocarbon group are fluorinated, more preferably 50% or more, and particularly preferably 60% or more, because this increases the hydrophobicity of the resist film during immersion exposure. Among them, Rf 101 is more preferably a fluorinated hydrocarbon group having 1 to 6 carbon atoms, and particularly preferably a trifluoromethyl group, -CH2-CF3, -CH2-CF2-CF3, -CH(CF3)2, -CH2-CH2-CF3, or -CH2-CH2-CF2-CF2-CF2-CF3.

[0368] The weight-average molecular weight (Mw) of component (F) (based on polystyrene standards measured by gel permeation chromatography) is preferably 1,000 to 50,000, more preferably 5,000 to 40,000, and most preferably 10,000 to 30,000. When the Mw is below the upper limit of this range, the component has sufficient solubility in a resist solvent for use as a resist, and when the Mw is above the lower limit of this range, the resulting resist film has good water repellency. The dispersity (Mw / Mn) of the component (F) is preferably from 1.0 to 5.0, more preferably from 1.0 to 3.0, and most preferably from 1.0 to 2.5.

[0369] In the resist composition of this embodiment, the component (F) may be used either as a single type, or in combination of two or more types. When the resist composition contains the component (F), the component (F) is typically used in an amount of 0.5 to 10 parts by mass per 100 parts by mass of the component (A1).

[0370] <Organic solvent component (S)> The resist composition of this embodiment can be produced by dissolving the resist materials in an organic solvent component (hereafter referred to as “component (S)”). The component (S) can be any solvent that is capable of dissolving the individual components used and forming a homogeneous solution, and any solvent that is appropriately selected from among those known as solvents for conventional chemically amplified resist compositions can be used. Examples of the component (S) include lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, and dipropylene glycol monoacetate; and compounds having an ether bond such as monoalkyl ethers or monophenyl ethers of the above polyhydric alcohols or compounds having an ester bond, such as monomethyl ether, monoethyl ether, monopropyl ether, and monobutyl ether. Examples of suitable solvents include derivatives of polyhydric alcohols (among which, propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred); cyclic ethers such as dioxane, and esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; aromatic organic solvents such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetole, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, and mesitylene, and dimethyl sulfoxide (DMSO). In the resist composition of this embodiment, the component (S) may be used either alone or as a mixed solvent of two or more different solvents. Of these, PGMEA, PGME, γ-butyrolactone, EL, and cyclohexanone are preferred.

[0371] A mixed solvent of PGMEA and a polar solvent is also preferred as component (S). The blending ratio (mass ratio) may be determined appropriately taking into consideration the compatibility of PGMEA with the polar solvent, but is preferably within the range of 1:9 to 9:1, and more preferably 2:8 to 8:2. More specifically, when EL or cyclohexanone is blended as the polar solvent, the mass ratio of PGMEA:EL or cyclohexanone is preferably 1:9 to 9:1, more preferably 2:8 to 8:2. When PGME is blended as the polar solvent, the mass ratio of PGMEA:PGME is preferably 1:9 to 9:1, more preferably 2:8 to 8:2, and even more preferably 3:7 to 7:3. Furthermore, a mixed solvent of PGMEA, PGME, and cyclohexanone is also preferred. Another preferred component (S) is a mixed solvent of at least one selected from PGMEA and EL with γ-butyrolactone, in which the mass ratio of the former to the latter is preferably 70:30 to 95:5. There are no particular restrictions on the amount of component (S) used, and it is set appropriately depending on the coating film thickness so as to provide a concentration that allows application to a substrate, etc. Generally, the component (S) is used so that the solids concentration of the resist composition falls within the range of 0.1 to 20 mass %, and preferably 0.2 to 15 mass %.

[0372] The resist composition of this embodiment may further contain, if desired, compatible additives such as an additional resin for improving the performance of the resist film, a dissolution inhibitor, a plasticizer, a stabilizer, a colorant, an antihalation agent, or a dye.

[0373] The resist composition of this embodiment may be prepared by dissolving the resist material in component (S) and then removing impurities using a polyimide porous film, a polyamideimide porous film, or the like. For example, the resist composition may be filtered using a filter made of a polyimide porous film, a filter made of a polyamideimide porous film, or a filter made of a polyimide porous film and a polyamideimide porous film. Examples of such polyimide porous films and polyamideimide porous films include those described in JP 2016-155121 A.

[0374] The resist composition of this embodiment described above contains a resin component (A1) having a structural unit (a0) represented by general formula (a0-1), and a photodegradable base (D0) whose conjugate acid has an acid dissociation constant (pKa) of 4.0 or less. The structural unit (a0) has Ar (a benzene ring or a naphthalene ring) with a hydroxy group bonded to the side chain terminal, i.e., a phenolic hydroxyl group (aromatic ring having a hydroxy group) that functions as a proton source. Furthermore, in the structural unit (a0), the bond between the oxygen atom (-O-) of the carbonyloxy group (-C(=O)-O-) in formula (a0-1) and the secondary carbon bonded to said oxygen atom is cleaved by the action of an acid, generating a carbocation. In the structural unit (a0), the hydroxy group bonded to Ar (a benzene ring or a naphthalene ring) donates an electron to Ar. This further reduces the electrical imbalance of the positive charge of the generated carbocation, further stabilizing the generated carbocation. Therefore, the deprotection reaction of the structural unit (a0) proceeds appropriately upon exposure to light. On the other hand, the photodegradable base (D0) has a conjugate acid (a compound with one hydrogen ion added to the anion moiety) with an acid dissociation constant (pKa) of 4.0 or less. The (D0) component decomposes in the exposed areas of the resist film, losing its acid diffusion control (basicity), and therefore does not function as a quencher. However, it functions as a quencher in the unexposed areas of the resist film, appropriately suppressing the diffusion of acid generated by exposure. This results in better pattern shapes. Due to the synergistic effect of the combination of the resin component (A1) containing the structural unit (a0) and the photodegradable base (D0) whose conjugated acid has a pKa of 4.0 or less, the resist composition of this embodiment can improve all of the sensitivity, resolution, roughness reduction, and rectangularity of the pattern shape.

[0375] (Method for forming a resist pattern) A method for forming a resist pattern according to a second aspect of the present invention is a method comprising the steps of forming a resist film on a support using the resist composition of the above-described embodiment, exposing the resist film to light, and developing the exposed resist film to form a resist pattern. One embodiment of the resist pattern forming method is, for example, a resist pattern forming method carried out as follows.

[0376] First, the resist composition of the above-described embodiment is applied onto a support using a spinner or the like, and then baked (post-apply bake (PAB)) at a temperature of, for example, 80 to 150°C for 40 to 120 seconds, preferably 60 to 90 seconds, to form a resist film. Next, the resist film is selectively exposed using an exposure device such as an electron beam lithography device or an EUV exposure device, either through a mask (mask pattern) on which a predetermined pattern has been formed, or by direct irradiation with electron beams without using a mask pattern, and then baked (post-exposure bake (PEB)) for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150°C. Next, the resist film is developed using an alkaline developer in the case of an alkaline development process, or a developer containing an organic solvent (organic developer) in the case of a solvent development process.

[0377] After the development process, a rinse process is preferably carried out. In the case of an alkaline development process, the rinse process is preferably a water rinse using pure water, and in the case of a solvent development process, it is preferable to use a rinse solution containing an organic solvent. In the case of a solvent development process, the developing treatment or rinsing treatment may be followed by a treatment of removing the developing solution or rinsing solution adhering to the pattern using a supercritical fluid. After the development treatment or rinsing treatment, the film is dried. In some cases, a baking treatment (post-baking) may be performed after the development treatment. In this manner, a resist pattern can be formed.

[0378] The support is not particularly limited, and conventionally known supports can be used, such as substrates for electronic components and those on which a predetermined wiring pattern is formed. More specifically, examples include silicon wafers, substrates made of metals such as copper, chromium, iron, and aluminum, and glass substrates. Materials that can be used for the wiring pattern include copper, aluminum, nickel, and gold. The support may also be a substrate as described above on which an inorganic and / or organic film is provided. Examples of inorganic films include inorganic anti-reflective coatings (inorganic BARCs). Examples of organic films include organic anti-reflective coatings (organic BARCs) and organic films such as lower organic films in multilayer resist methods. Here, the multilayer resist method is a method in which at least one organic film (lower organic film) and at least one resist film (upper resist film) are provided on a substrate, and the lower organic film is patterned using the resist pattern formed on the upper resist film as a mask, and it is said to be able to form patterns with a high aspect ratio. In other words, with the multilayer resist method, the required thickness can be ensured by the lower organic film, so the resist film can be made thinner and fine patterns with a high aspect ratio can be formed. Multilayer resist methods are basically divided into a two-layer structure consisting of an upper resist film and a lower organic film (two-layer resist method), and a three-layer structure consisting of three or more layers with one or more intermediate layers (such as a metal thin film) between the upper resist film and the lower organic film (three-layer resist method).

[0379] The wavelength used for exposure is not particularly limited, and radiation such as an ArF excimer laser, a KrF excimer laser, an F2 excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-rays, or soft X-rays can be used. The resist composition is highly useful for KrF excimer lasers, ArF excimer lasers, EB, or EUV, more useful for ArF excimer lasers, EB, or EUV, and particularly useful for EB or EUV. That is, the method of forming a resist pattern according to this embodiment is particularly useful when the step of exposing the resist film includes exposing the resist film to EUV (extreme ultraviolet) or EB (electron beam).

[0380] The exposure method for the resist film may be a normal exposure (dry exposure) carried out in air or an inert gas such as nitrogen, or may be liquid immersion lithography. Immersion exposure is an exposure method in which the space between the resist film and the lowest lens of the exposure device is filled with a solvent (immersion medium) that has a refractive index greater than that of air, and then exposure (immersion exposure) is performed in that state. The immersion medium is preferably a solvent having a refractive index greater than that of air and less than that of the resist film to be exposed. The refractive index of such a solvent is not particularly limited as long as it is within the above range. Examples of solvents having a refractive index greater than that of air and smaller than that of the resist film include water, fluorine-based inert liquids, silicon-based solvents, and hydrocarbon-based solvents. Specific examples of the fluorine-based inert liquid include liquids containing as a main component a fluorine-based compound such as C3HCl2F5, C4F9OCH3, C4F9OC2H5, or C5H3F7, and preferably have a boiling point of 70 to 180° C., more preferably 80 to 160° C. If the fluorine-based inert liquid has a boiling point within the above range, it is preferable because the medium used for immersion can be removed simply and easily after exposure is completed. As the fluorine-based inert liquid, particularly preferred are perfluoroalkyl compounds in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms, specifically perfluoroalkyl ether compounds and perfluoroalkylamine compounds. More specifically, the perfluoroalkyl ether compound may include perfluoro(2-butyl-tetrahydrofuran) (boiling point: 102°C), and the perfluoroalkylamine compound may include perfluorotributylamine (boiling point: 174°C). As the liquid immersion medium, water is preferably used from the viewpoints of cost, safety, environmental issues, versatility, and the like.

[0381] The alkaline developer used in the development treatment in the alkaline development process may be, for example, a 0.1 to 10 mass % aqueous solution of tetramethylammonium hydroxide (TMAH). The organic solvent contained in the organic developer used in the development treatment in the solvent development process may be any organic solvent capable of dissolving component (A) (component (A) before exposure), and may be appropriately selected from known organic solvents. Specific examples include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, and ether solvents, as well as hydrocarbon solvents. Ketone-based solvents are organic solvents that contain CC(=O)-C in their structure. Ester-based solvents are organic solvents that contain CC(=O)-OC in their structure. Alcohol-based solvents are organic solvents that contain an alcoholic hydroxyl group in their structure. "Alcoholic hydroxyl group" means a hydroxyl group bonded to a carbon atom of an aliphatic hydrocarbon group. Nitrile-based solvents are organic solvents that contain a nitrile group in their structure. Amide-based solvents are organic solvents that contain an amide group in their structure. Ether-based solvents are organic solvents that contain COC in their structure. Some organic solvents contain multiple types of functional groups that characterize the above-mentioned solvents in their structure, and in such cases, the term "organic solvent" refers to any solvent type containing the functional groups possessed by the organic solvent. For example, diethylene glycol monomethyl ether is considered to be both an alcohol-based solvent and an ether-based solvent in the above classification. The hydrocarbon solvent is a hydrocarbon solvent that is composed of a hydrocarbon that may be halogenated and has no substituents other than halogen atoms, and the halogen atoms are preferably fluorine atoms. Of the above, the organic solvent contained in the organic developer is preferably a polar solvent, and more preferably a ketone solvent, an ester solvent, a nitrile solvent, or the like.

[0382] Examples of ketone solvents include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, phenylacetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methyl naphthyl ketone, isophorone, propylene carbonate, γ-butyrolactone, methyl amyl ketone (2-heptanone), etc. Among these, methyl amyl ketone (2-heptanone) is preferred as the ketone solvent.

[0383] Examples of ester solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2-ethoxybutyl ether ... Dibutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, 4-methyl-4-methoxypentyl acetate, propylene glycol diacetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate Examples of the ester solvent include butyl acetate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl 3-methoxypropionate, etc. Among these, butyl acetate is preferred as the ester solvent.

[0384] Examples of nitrile solvents include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

[0385] Known additives can be blended into the organic developer as needed. Examples of such additives include surfactants. The surfactant is not particularly limited, but examples include ionic or nonionic fluorine-based and / or silicon-based surfactants. Nonionic surfactants are preferred, and nonionic fluorine-based surfactants or nonionic silicon-based surfactants are more preferred. When a surfactant is added, the amount added is usually 0.001 to 5 mass %, preferably 0.005 to 2 mass %, and more preferably 0.01 to 0.5 mass %, based on the total amount of the organic developer.

[0386] The development process can be carried out by a known development method, such as a method of immersing the support in a developer for a certain period of time (dip method), a method of piling up the developer on the surface of the support by surface tension and leaving it standing for a certain period of time (puddle method), a method of spraying the developer onto the surface of the support (spray method), or a method of continuously applying the developer while scanning a developer application nozzle at a constant speed onto a support rotating at a constant speed (dynamic dispense method).

[0387] The organic solvent contained in the rinse solution used in the rinsing treatment after development in the solvent development process can be appropriately selected from the organic solvents listed above as organic solvents used in the organic developer, and can be one that does not easily dissolve the resist pattern. Usually, at least one solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents is used. Among these, at least one solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, and amide solvents is preferred, at least one solvent selected from alcohol solvents and ester solvents is more preferred, and alcohol solvents are particularly preferred. The alcohol-based solvent used in the rinse liquid is preferably a monohydric alcohol having 6 to 8 carbon atoms, and the monohydric alcohol may be linear, branched, or cyclic. Specific examples include 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, and benzyl alcohol. Of these, 1-hexanol, 2-heptanol, and 2-hexanol are preferred, and 1-hexanol and 2-hexanol are more preferred. These organic solvents may be used alone or in combination of two or more. They may also be used in combination with other organic solvents or water. However, taking into consideration the development characteristics, the amount of water in the rinse solution is preferably 30% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 3% by mass or less, based on the total amount of the rinse solution. The rinse solution may contain known additives as needed. Examples of such additives include surfactants. Examples of surfactants include those described above, with nonionic surfactants being preferred, and nonionic fluorine-based surfactants or nonionic silicone-based surfactants being more preferred. When a surfactant is added, the amount added is usually 0.001 to 5 mass %, preferably 0.005 to 2 mass %, and more preferably 0.01 to 0.5 mass %, based on the total amount of the rinse liquid.

[0388] The rinse treatment (cleaning treatment) using a rinse solution can be carried out by a known rinse method, such as a method of continuously applying the rinse solution onto a support rotating at a constant speed (spin coating method), a method of immersing the support in the rinse solution for a certain period of time (dipping method), or a method of spraying the rinse solution onto the surface of the support (spray method).

[0389] According to the method of forming a resist pattern of the present embodiment as explained above, the resist composition of the above-mentioned embodiment is used, and therefore a resist pattern that is excellent in sensitivity, resolution, and roughness reduction, and that also has a high degree of rectangularity, can be formed. [Example]

[0390] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0391] <Preparation of Resist Composition> (Examples 1 to 22, Comparative Examples 1 and 2) The components shown in Tables 1 and 2 were mixed and dissolved to prepare resist compositions of the respective examples. It should be noted that Example 10 is a reference example.

[0392] [Table 1]

[0393] [Table 2]

[0394] In Tables 1 and 2, the abbreviations have the following meanings: The numbers in brackets [ ] are the blend amounts (parts by mass). (A)-1: Polymer compound represented by the following chemical formula (A1-1). The weight-average molecular weight (Mw) calculated in terms of standard polystyrene by GPC measurement is 7000, and the molecular weight dispersity (Mw / Mn) is 1.66. The polymerization composition ratio (proportion (molar ratio) of the structural units in the structural formula) is 100. (A)-2: Polymer compound represented by the following chemical formula (A1-2). The weight average molecular weight (Mw) calculated in terms of standard polystyrene by GPC measurement is 6,600, and the molecular weight dispersity (Mw / Mn) is 1.62. 13 The copolymer composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) determined by C-NMR was l / m = 50 / 50. (A)-3: Polymer compound represented by the following chemical formula (A1-3). The weight average molecular weight (Mw) calculated in terms of standard polystyrene by GPC measurement is 7,200, and the molecular weight dispersity (Mw / Mn) is 1.71. 13 The copolymer composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) determined by C-NMR was l / m = 50 / 50. (A)-4: Polymer compound represented by the following chemical formula (A1-4): The weight average molecular weight (Mw) calculated in terms of standard polystyrene by GPC measurement is 6700, and the molecular weight dispersity (Mw / Mn) is 1.66. 13 The copolymer composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) determined by C-NMR was l / m = 50 / 50. (A)-5: Polymer compound represented by the following chemical formula (A1-5). The weight average molecular weight (Mw) calculated in terms of standard polystyrene by GPC measurement is 6,800, and the molecular weight dispersity (Mw / Mn) is 1.70. 13 The copolymer composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) determined by C-NMR was l / m = 50 / 50. (A)-6: Polymer compound represented by the following chemical formula (A1-6). The weight average molecular weight (Mw) calculated in terms of standard polystyrene by GPC measurement is 6700, and the molecular weight dispersity (Mw / Mn) is 1.71. 13 The copolymer composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) determined by C-NMR was l / m = 50 / 50. (A)-7: Polymer compound represented by the following chemical formula (A1-7): The weight average molecular weight (Mw) calculated in terms of standard polystyrene by GPC measurement is 6,600, and the molecular weight dispersity (Mw / Mn) is 1.65. 13 The copolymer composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) determined by C-NMR was l / m = 50 / 50. (A)-8: Polymer compound represented by the following chemical formula (A1-8). The weight average molecular weight (Mw) calculated in terms of standard polystyrene by GPC measurement is 7000, and the molecular weight dispersity (Mw / Mn) is 1.67. 13 The copolymer composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) determined by C-NMR was l / m = 50 / 50. (A)-9: Polymer compound represented by the following chemical formula (A1-9): The weight average molecular weight (Mw) calculated in terms of standard polystyrene by GPC measurement is 6900, and the molecular weight dispersity (Mw / Mn) is 1.67. 13 The copolymer composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) determined by C-NMR was l / m = 50 / 50. (A)-10: Polymer compound represented by the following chemical formula (A1-10). The weight average molecular weight (Mw) calculated in terms of standard polystyrene by GPC measurement is 7000, and the molecular weight dispersity (Mw / Mn) is 1.66. 13 The copolymer composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) determined by C-NMR was l / m = 50 / 50. (A)-11: Polymer compound represented by the following chemical formula (A1-11): The weight average molecular weight (Mw) calculated in terms of standard polystyrene by GPC measurement is 6,600, and the molecular weight dispersity (Mw / Mn) is 1.68. 13 The copolymer composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) determined by C-NMR was l / m = 50 / 50. (A)-12: Polymer compound represented by the following chemical formula (A1-12). The weight average molecular weight (Mw) calculated in terms of standard polystyrene by GPC measurement is 7000, and the molecular weight dispersity (Mw / Mn) is 1.70. 13 The copolymer composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) determined by C-NMR was l / m = 50 / 50. (A)-13: Polymer compound represented by the following chemical formula (A1-13). The weight average molecular weight (Mw) calculated in terms of standard polystyrene by GPC measurement is 6,800, and the molecular weight dispersity (Mw / Mn) is 1.71. 13 The copolymer composition ratio (proportion (molar ratio) of each structural unit in the structural formula) determined by C-NMR was l / m / n = 20 / 30 / 50.

[0395] (A)-14: Polymer compound represented by the following chemical formula (A2-1). The weight average molecular weight (Mw) calculated in terms of standard polystyrene by GPC measurement is 6,600, and the molecular weight dispersity (Mw / Mn) is 1.66. 13 The copolymer composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) determined by C-NMR was l / m = 50 / 50.

[0396] [ka]

[0397] [ka]

[0398] (B)-1: An acid generator comprising a compound represented by the following chemical formula (B1-1).

[0399] [ka]

[0400] (D)-1: A photodegradable base consisting of a compound represented by the following chemical formula (D0-1): The acid dissociation constant (pKa) of the conjugate acid is 1.3. (D)-2: A photodegradable base consisting of a compound represented by the following chemical formula (D0-2): The acid dissociation constant (pKa) of the conjugate acid is 3.0. (D)-3: A photodegradable base consisting of a compound represented by the following chemical formula (D0-3): The acid dissociation constant (pKa) of the conjugate acid is 3.3. (D)-4: A photodegradable base consisting of a compound represented by the following chemical formula (D0-4): The acid dissociation constant (pKa) of the conjugate acid is 3.0. (D)-5: A photodegradable base consisting of a compound represented by the following chemical formula (D0-5): The acid dissociation constant (pKa) of the conjugate acid is 3.0. (D)-6: A photodegradable base consisting of a compound represented by the following chemical formula (D0-6). The acid dissociation constant (pKa) of the conjugate acid is 1.3. (D)-7: A photodegradable base consisting of a compound represented by the following chemical formula (D0-7): The acid dissociation constant (pKa) of the conjugate acid is 1.3. (D)-8: A photodegradable base consisting of a compound represented by the following chemical formula (D0-8). The acid dissociation constant (pKa) of the conjugate acid is 1.3. (D)-9: A photodegradable base consisting of a compound represented by the following chemical formula (D0-9): The acid dissociation constant (pKa) of the conjugate acid is 1.3. (D)-10: A photodegradable base consisting of a compound represented by the following chemical formula (D0-10): The acid dissociation constant (pKa) of the conjugate acid is 3.0. (D)-11: A photodegradable base consisting of a compound represented by the following chemical formula (D1-1): The acid dissociation constant (pKa) of the conjugate acid is 4.2. For the above (D)-1 to (D)-11, the acid dissociation constants (pKa) of the conjugate acids were calculated from simulations using "ACD / Labs" (trade name, manufactured by Advanced Chemistry Development) software.

[0401] [ka]

[0402] [ka]

[0403] (S)-1: A mixed solvent of propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether=60 / 40 (mass ratio).

[0404] <Formation of Resist Pattern> Each resist composition of each example was applied using a spinner onto an 8-inch silicon substrate that had been treated with hexamethyldisilazane (HMDS), and then pre-baked (PAB) on a hot plate at 110°C for 60 seconds, followed by drying to form a resist film with a thickness of 30 nm. Next, the resist film was subjected to exposure to light using an electron beam lithography system JEOL-JBX-9300FS (manufactured by JEOL Ltd.) at an acceleration voltage of 100 kV to form a 1:1 line and space pattern (hereinafter referred to as "LS pattern") with a target size of 50 nm line width, followed by post-exposure baking (PEB) at 90°C for 60 seconds. Next, alkaline development was carried out at 23° C. for 60 seconds using a 2.38 mass % tetramethylammonium hydroxide (TMAH) aqueous solution "NMD-3" (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.). Thereafter, the substrate was rinsed with pure water for 15 seconds. As a result, a 1:1 LS pattern with a line width of 50 nm was formed.

[0405] [Evaluation of optimal exposure (Eop)] The optimum exposure dose Eop (μC / cm) for forming a target size LS pattern by the above <Formation of resist pattern> 2 This is called "Eop (μC / cm 2 )" are shown in Tables 3 and 4.

[0406] [Evaluation of LWR (Line Width Roughness)] For the LS patterns formed in the above <Formation of Resist Pattern>, 3σ, a measure of LWR, was determined, and this is shown in Tables 3 and 4 as "LWR (nm)". "3σ" indicates three times the standard deviation (σ) (unit: nm) obtained from the measurement results of measuring 400 line positions in the longitudinal direction of the line using a scanning electron microscope (accelerating voltage 800 V, product name: S-9380, manufactured by Hitachi High-Technologies Corporation). The smaller the 3σ value, the less rough the line sidewalls are, meaning that an LS pattern with a more uniform width is obtained.

[0407] [Resolution evaluation] The limiting resolution at the Eop, specifically, the minimum dimension of the pattern that can be resolved without collapsing when forming an LS pattern by gradually increasing the exposure dose from the optimal exposure dose Eop, was determined using a scanning electron microscope S-9380 (manufactured by Hitachi High-Technologies Corporation). This is shown in Tables 3 and 4 as the "limiting resolution (nm)."

[0408] [Evaluation of pattern shape] The cross-sectional shape of each LS pattern obtained in the above <Formation of Resist Pattern> was observed using a scanning electron microscope (accelerating voltage 800V, product name: SU-8000, manufactured by Hitachi High-Technologies Corporation). This shape was evaluated according to the following evaluation criteria. The results are shown in Tables 3 and 4 as "pattern shape." Evaluation criteria ⊚: The cross section of the pattern is rectangular and highly perpendicular. ◯: The perpendicularity of the cross-sectional shape of the pattern is slightly inferior to that of ⊚. ×: The cross-sectional shape of the pattern is top-rounding (the top of the pattern is round) or T-top shape.

[0409] [Table 3]

[0410] [Table 4]

[0411] As shown in Tables 3 and 4, the resist compositions of Examples 1 to 22, to which the present invention was applied, were superior in sensitivity, resolution, and roughness reduction compared to the resist compositions of Comparative Examples 1 and 2, and were able to form resist patterns with high rectangularity.

Claims

1. A resist composition that generates an acid upon exposure and whose solubility in a developer changes due to the action of the acid, a resin component (A1) whose solubility in a developer changes under the action of an acid; a photodegradable base (D0) that controls the diffusion of acid generated upon exposure to light; Contains The resin component (A1) has a structural unit (a0) represented by the following general formula (a0-1): The photodegradable base (D0) contains a compound represented by the following general formula (d0-1): The resist composition, wherein the acid dissociation constant (pKa) of the conjugate acid of the photodegradable base (D0) is 4.0 or less. 【Chemical 1】 [In the formula, R ０１ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ０１ is a single bond or a divalent linking group. ０１ represents a hydrocarbon group which may have a substituent. ０２ is a single bond. ０２ is a hydrogen atom, a hydroxy group, or a hydrocarbon group which may have a substituent. Ar is a benzene ring or a naphthalene ring. ０１ and Ra ０２ are mutually bonded to form Ra ０１ and Ya ０２ and a secondary carbon atom to which Ya is bonded. ０２ And, Ya ０２ The carbon atom of Ar to which Ra is bonded ０２ may form a ring together with the carbon atom of Ar to which n is bonded. n01 is an integer of 1 to 6, as far as valence allows. 【Chemistry 2】 [In the formula, R d0 is a substituent. q 0 is an integer of 0 to 3. n 0 is an integer of 1 or more. p 0 is an integer of 0 or more. When p 0 is 2 or more, multiple R d0 s may be the same or different, provided that n 0 +p 0 ≦(q 0 ×2)+5. m is an integer of 1 or more, and M m+ is an m-valent organic cation.]

2. 10. A method for forming a resist pattern, comprising the steps of: forming a resist film on a support using the resist composition according to claim 1; exposing the resist film; and developing the exposed resist film to form a resist pattern.

3. 3. The method for forming a resist pattern according to claim 2, wherein in the step of exposing the resist film, the resist film is exposed to EUV (extreme ultraviolet) or EB (electron beam).

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