Resist composition, resist pattern forming method, and polymer compound

Abstract

To provide a resist composition which, in forming a resist pattern, achieves higher sensitivity, lowers LWR, provides high etching resistance, and suppresses film reduction (DL) due to a developer solution.SOLUTION: A resist composition contains a resin component (A1) having a structural unit (a01) represented by general formula (a01), a structural unit (a02) represented by general formula (a02), and a structural unit (a10) represented by general formula (a10), wherein na11 and na21 are each independently 0 or 1, Ra01 is hydrogen or a linear or branched alkyl group, Ra02 is a linear or branched alkyl group, and na12 and na22 are each independently 1 or 2.SELECTED DRAWING: None

Description

[Technical Field]

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

[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. In chemically amplified resist compositions, a resin having a plurality of structural units is generally used as the base component in order to improve lithography properties and the like.

[0004] For example, Patent Document 1 discloses a resist composition containing a resin component having a structural unit to which an acid-dissociable group having an unsaturated bond is bonded. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-120759 Summary of the Invention [Problem to be solved by the invention]

[0006] With the further advancement of lithography technology and the expansion of its application fields, patterns are rapidly becoming finer. Accordingly, when manufacturing semiconductor devices, etc., technology that can form fine patterns with good shapes is required. For example, in lithography using EUV or EB, the goal is to form fine patterns of several tens of nanometers. However, conventional resist compositions such as those described in Patent Document 1 require further improvement in resolution.

[0007] The present invention has been made in light of the above-mentioned circumstances, and an object of the present invention is to provide a resist composition that, when forming a resist pattern, achieves high sensitivity, reduced LWR, high etching resistance, and suppressed film loss (DL) due to a developer; a method of forming a resist pattern that uses the resist composition; and a polymeric compound that is useful as a raw material for the base component used in 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 acid upon exposure and whose solubility in a developer changes due to the action of the acid, the resist composition containing a resin component (A1) whose solubility in a developer changes due to the action of the acid, the resin component (A1) having a structural unit (a01) represented by the following general formula (a0-1), a structural unit (a02) represented by the following general formula (a0-2), and a structural unit represented by the following general formula (a10-1):

[0009] [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. n a11 represents 0 or 1. Ra 01 is hydrogen or a linear or branched alkyl group. n a12 is 1 or 2.

[0010] [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. na21 represents 0 or 1. Ra 02 is a linear or branched alkyl group. na22 is 1 or 2.]

[0011] [ka] [Wherein W is a polymerizable group-containing group. x0 is an aromatic hydrocarbon group which may have a substituent. nax0 is an integer of 1 or more.

[0012] 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 according to the first aspect, exposing the resist film to light, and developing the exposed resist film to form a resist pattern.

[0013] A third aspect of the present invention is a polymeric compound having a structural unit (a01) represented by the following general formula (a0-1), a structural unit (a02) represented by the following general formula (a0-2), and a structural unit represented by the following general formula (a10-1):

[0014] [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. na11 and na12 each independently represent 0 or 1. Ra 01 is hydrogen or a linear or branched alkyl group.

[0015] [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. na21 and na22 each independently represent 0 or 1. Ra 02 is a linear or branched alkyl group.

[0016] [ka] [Wherein W is a polymerizable group-containing group. x0 is an aromatic hydrocarbon group which may have a substituent. nax0 is an integer of 1 or more. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a resist composition that, when forming a resist pattern, achieves high sensitivity, reduced LWR, high etching resistance, and suppresses film loss (DL) due to a developer; a method of forming a resist pattern that uses the resist composition; and a polymeric compound that is useful as a raw material for the base component used in the resist composition. DETAILED DESCRIPTION OF THE INVENTION

[0018] 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.

[0019] 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 hydroxyl group, an amino group, and a sulfo group (-SO3H). 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).

[0020] 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.

[0021] A "base component" is an organic compound that has film-forming ability. Organic compounds used as base components are broadly classified into non-polymers and polymers. Non-polymers typically have a molecular weight of 500 or more and less than 4000 (hereinafter referred to as "low molecular weight compounds"). 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).

[0022] 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 "acrylate 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.

[0023] 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.

[0024] 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.

[0025] (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) (hereafter also referred to as "component (A)") whose solubility in a developer changes under the action of an acid. In the resist composition of this embodiment, the component (A) contains a resin component (A1) (hereafter also referred to as "component (A1)") whose solubility in a developer changes under the action of an acid. The component (A1) contains a structural unit (a01) represented by general formula (a0-1), a structural unit (a02) represented by general formula (a0-2), and a structural unit (a10) represented by general formula (a10-1), which will be described below. Furthermore, the resist composition of this embodiment may further contain other components in addition to the component (A). Examples of other components include the component (B), component (D), component (E), component (F), and component (S), which will be described later.

[0026] In the resist composition of this embodiment, the component (A) may generate an acid upon exposure, or an additive component that is formulated separately from the component (A) may generate an acid upon exposure. Specifically, the resist composition of this embodiment may further contain: (1) an acid generator component (B) (hereinafter referred to as “component (B)”) that generates acid upon exposure; (2) the component (A) may be a component that generates acid upon exposure; or (3) the component (A) may be a component that generates acid upon exposure and may further contain component (B). That is, in the cases of (2) and (3) above, the component (A) is a "base component that generates acid upon exposure and whose solubility in a developer changes due to the action of the acid." When the component (A) is a base component that generates acid upon exposure and whose solubility in a developer changes due to the action of the acid, the component (A1) described below is preferably a resin that generates acid upon exposure and whose solubility in a developer changes due to the action of the acid. Such a resin can be a polymeric compound having a structural unit that generates acid upon exposure. The structural unit that generates acid upon exposure can be, for example, the structural unit (a5) described below.

[0027] Of the above, the resist composition of this embodiment is preferably the above-mentioned case (1). That is, the resist composition of this embodiment preferably contains the component (A) and the component (B).

[0028] When a resist film is formed using the resist composition of this embodiment and then subjected to selective exposure, an acid is generated from the component (B) in the exposed areas of the resist film, for example, and the action of the acid changes the solubility of the component (A) in a developer, whereas the solubility of the component (A) in the 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. Therefore, when the resist film is developed, if the resist composition is positive, the exposed areas of the resist film are dissolved and removed, forming a positive resist pattern, whereas if the resist composition is negative, the unexposed areas of the resist film are dissolved and removed, forming a negative resist pattern.

[0029] 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 an alkaline development process in which an alkaline developer is used in the development treatment during resist pattern formation, or may be for a solvent development process in which a developer containing an organic solvent (organic developer) is used in the development treatment.

[0030] <Component (A)> In the resist composition of this embodiment, by using the component (A1), the polarity of the base component changes between before and after exposure, and therefore good development contrast can be obtained not only in an alkali development process but also in a solvent development process. As the component (A), other polymeric compounds and / or low molecular weight compounds may be used in combination with the component (A1).

[0031] 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.

[0032] About component (A1) The component (A1) is a resin component whose solubility in a developer changes under the action of an acid. In this embodiment, the component (A1) has a structural unit (a01) represented by general formula (a0-1), a structural unit (a02) represented by general formula (a0-2), and a structural unit (a10) represented by general formula (a10-1), which will be described later. The component (A1) may contain other structural units, in addition to the structural units (a01), (a02), and (a10), as necessary.

[0033] <Constituent unit (a01)> The structural unit (a01) is a structural unit represented by the following general formula (a01).

[0034] [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. n a11 represents 0 or 1. Ra 01 is hydrogen or a linear or branched alkyl group. n a12 is 1 or 2.

[0035] In the general formula (a01), 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. As the halogen atom, a fluorine atom is 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.

[0036] In the general formula (a01), na11 is preferably 0.

[0037] In the general formula (a01), Ra 01 The linear or branched alkyl group in is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and 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. Among them, Ra 01 is preferably a hydrogen atom or a methyl group, more preferably a methyl group.

[0038] In the general formula (a01), na12 is preferably 1.

[0039] Specific preferred examples of the structural unit (a01) are shown below. In the following formula, R αrepresents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0040] [ka]

[0041] The structural unit (a01) contained in the component (A1) may be of one type, or may be of two or more types. The proportion of the structural unit (a01) in the component (A1) relative to the total (100 mol %) of all structural units constituting the component (A1) is preferably 15 to 45 mol %, more preferably 20 to 40 mol %, and even more preferably 25 to 35 mol %. By ensuring that the proportion of the structural unit (a01) is at least as large as the lower limit of the preferred range, solubility in a developer is likely to be increased, film loss (DL) is likely to be suppressed, and etching resistance is likely to be improved. On the other hand, by ensuring that the proportion is at most the upper limit of the preferred range, a balance with other structural units can be achieved, resulting in various favorable lithography properties.

[0042] <Constituent unit (a02)> The structural unit (a02) is a structural unit represented by the following general formula (a02).

[0043] [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. na21 and na22 each independently represent 0 or 1. Ra 02 is a linear or branched alkyl group.

[0044] In the general formula (a02), 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. As the halogen atom, a fluorine atom is 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.

[0045] In the general formula (a02), na21 is preferably 0.

[0046] In the general formula (a02), Ra 02 The linear or branched alkyl group in is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and 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. Among them, Ra 02 As the alkyl group, a methyl group, an ethyl group, or an isopropyl group is preferred, and an isopropyl group is more preferred.

[0047] In the general formula (a02), na22 is preferably 2.

[0048] Specific preferred examples of the structural unit (a01) are shown below. In the following formula, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0049] [ka]

[0050] The structural unit (a02) contained in the component (A1) may be of one type, or may be of two or more types. The proportion of the structural unit (a02) in the component (A1) relative to the total (100 mol %) of all structural units constituting the component (A1) is preferably 15 to 45 mol %, more preferably 20 to 40 mol %, and even more preferably 25 to 35 mol %. By ensuring that the proportion of the structural unit (a02) is at least as large as the lower limit of the above-mentioned preferred range, dissolution contrast is less likely to occur at the boundary between exposed and unexposed areas, and LWR is likely to be improved. On the other hand, by ensuring that the proportion is at most the upper limit of the above-mentioned preferred range, a balance with other structural units can be achieved, resulting in various favorable lithography properties.

[0051] <Structural unit (a10)> The structural unit (a10) is a structural unit represented by the following general formula (a10-1).

[0052] [ka] [Wherein W is a polymerizable group-containing group. x0 is an aromatic hydrocarbon group which may have a substituent. nax0 is an integer of 1 or more.

[0053] In the general formula (a10-1), W represents a polymerizable group-containing group. The "polymerizable group" refers to a group that enables a compound having the polymerizable group to be polymerized by radical polymerization or the like, and refers to a group that contains a multiple bond between carbon atoms, such as an ethylenic double bond. Examples of the polymerizable group include a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a fluorovinyl group, a difluorovinyl group, a trifluorovinyl group, a difluorotrifluoromethylvinyl group, a trifluoroallyl group, a perfluoroallyl group, a trifluoromethylacryloyl group, a nonylfluorobutylacryloyl group, a vinyl ether group, a fluorine-containing vinyl ether group, an allyl ether group, a fluorine-containing allyl ether group, a styryl group, a vinyl naphthyl group, a fluorine-containing styryl group, a fluorine-containing vinyl naphthyl group, a norbornyl group, a fluorine-containing norbornyl group, and a silyl group.

[0054] The polymerizable group-containing group may be a group composed only of a polymerizable group, or may be a group composed of a polymerizable group and a group other than the polymerizable group. Examples of the group other than the polymerizable group include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. Examples of the polymerizable group-containing group include a group represented by the formula: C(R X11 )(R X12 )=C(R X13 )-Ya x0 In the above formula, R X11 , R X12 and R X13 each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; x0 represents a single bond or a divalent linking group. x0 Examples of the divalent linking group in the formula (Ya) include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. x0 Examples of the divalent linking group in the formula include an ester bond (-C(=O)-O-), an oxycarbonyl group (-OC(=O)-), an ether bond (-O-), a linear or branched alkylene group, or a combination thereof. x0 is preferably a single bond, an ester bond (-C(=O)-O-), or an oxycarbonyl group (-OC(=O)-).

[0055] In the formula (a10-1), Wa x0 is an aromatic hydrocarbon group which may have a substituent. Wa x0 The aromatic hydrocarbon group in the formula (n) is an aromatic ring which may have a substituent. ax0Examples of the aromatic ring include groups in which 4n+1) hydrogen atoms have been removed. The aromatic ring here is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons. 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 x0 The aromatic hydrocarbon group in (n) is selected from aromatic compounds containing an aromatic ring which may have two or more substituents (for example, biphenyl, fluorene, etc.). ax0 +1) hydrogen atoms may also be removed. Among the above, Wa x0 As examples, benzene, naphthalene, anthracene, or biphenyl (n ax0 A group in which (n +1) hydrogen atoms have been removed from benzene or naphthalene is preferred. ax0 A group obtained by removing (n +1) hydrogen atoms from benzene is more preferred. ax0 A group in which +1) hydrogen atoms have been removed is more preferred.

[0056] Wa x0 The aromatic hydrocarbon group in the formula (a10-1-1) may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, and a halogenated alkyl group. Examples of the alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent include Ya in the general formula (a10-1-1) described below. x1 Examples of the substituent include the same as those exemplified as the substituent of the cyclic alicyclic hydrocarbon group in Wa. The substituent is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, more preferably a linear or branched alkyl group having 1 to 3 carbon atoms, further preferably an ethyl group or a methyl group, and particularly preferably a methyl group.x0 The aromatic hydrocarbon group in the formula (I) preferably does not have a substituent.

[0057] In the formula (a10-1), n ax0 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.

[0058] The structural unit (a10) is preferably a structural unit represented by the following general formula (a10-1-1).

[0059] [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 an aromatic hydrocarbon group which may have a substituent. ax1 is an integer greater than or equal to 1.]

[0060] In the formula (a10-1-1), R represents a hydrogen atom, an alkyl group of 1 to 5 carbon atoms, or a halogenated alkyl group of 1 to 5 carbon atoms. 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 hydrogen atom.

[0061] In the formula (a10-1-1), Ya x1 is a single bond or a divalent linking group. In the above chemical formula, Ya x1 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.

[0062] Ya x1is 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)-].

[0063] In the formula (a10-1-1), Wa x1 The aromatic hydrocarbon group which may have a substituent is Wa in the formula (a10-1). x0 The aromatic hydrocarbon group may have a substituent, as defined above.

[0064] In the formula (a10-1-1), 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.

[0065] 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.

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] 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 20 to 55 mol %, more preferably 25 to 50 mol %, and even more preferably 30 to 45 mol %, based on the total (100 mol %) of all structural units constituting the component (A1). By ensuring that the proportion of the structural unit (a10) is at least as large as the lower limit of the above range, sensitivity can be further improved, while by ensuring that the proportion is at most the upper limit, it is easier to achieve a balance with other structural units.

[0070] Other structural units The component (A1) may contain other structural units as needed, in addition to the aforementioned structural units (a01), (a02), and (a10). Examples of other structural units include structural units (a1) containing an acid-decomposable group whose polarity increases when acted upon by acid (provided that structural units (a01) and (a02) are excluded); structural units (a10) represented by the following general formula (a10-1); structural units (a5) that generate acid upon exposure; structural units (a6) that have acid diffusion-controlling properties; structural units (a2) that contain a lactone-containing cyclic group; and structural units (a8) derived from compounds represented by the following general formula (a8-1).

[0071] Structural unit (a1): The structural unit (a1) is a structural unit (excluding those that fall under the category of the structural unit (a01) and the structural unit (a02)) that contains an acid-decomposable group whose polarity increases when acted upon by an acid.

[0072] 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.

[0073] 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").

[0074] [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' 2 may be bonded to any one of the following to form a ring.]

[0075] 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, examples of the alkyl group include the same alkyl groups as those exemplified as the substituent that may be bonded to the carbon atom at the α-position in the description of the α-substituted acrylic acid ester above, and an alkyl group having 1 to 5 carbon atoms is preferred. Specific examples include linear or branched alkyl groups. More specific examples include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, and neopentyl groups, with methyl and ethyl groups being more preferred, and methyl being particularly preferred.

[0076] 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, 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.

[0077] 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, with an isopropyl group being preferred.

[0078] Ra' 3 When is a cyclic hydrocarbon group, the hydrocarbon group may be an alicyclic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The alicyclic 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 is preferably one having 7 to 12 carbon atoms, specific examples of which include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0079] 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, further 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' 3 Specific 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.

[0080] 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 x5 ") are also examples. where R P1is a monovalent chain 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 P2 Some 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, 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. 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.

[0081] 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.

[0082] 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.

[0083] [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.

[0084] Ra' 4 Examples of the hydrocarbon group include a linear or branched alkyl group, a linear or cyclic alkenyl group, a linear alkynyl group, and a cyclic hydrocarbon group. Ra' 4 The linear or branched alkyl group and the cyclic hydrocarbon group (the monocyclic alicyclic hydrocarbon group, the polycyclic alicyclic 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.

[0085] Ra' 5 and Ra' 6and (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).

[0086] [ka] [In formula (a1-r2-1), Ra' 10 Ra' represents a linear or branched alkyl group having 1 to 12 carbon atoms, some of which may be substituted with a halogen atom or a heteroatom-containing group. 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 101 ~Ra 103 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. 101 ~Ra 103 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 104 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. 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 (the same applies hereinafter).

[0087] In the above formula (a1-r2-1), Ra' 10 is a linear or branched alkyl group having 1 to 12 carbon atoms, some of which may be substituted with a halogen atom or a heteroatom-containing group.

[0088] Ra' 10 The linear alkyl group in the formula (I) has 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, and particularly preferably 1 to 5 carbon atoms. Ra' 10 In the formula (I), the branched alkyl group is the above-mentioned Ra' 3 The same can be mentioned.

[0089] Ra' 10 The alkyl group in may be partially substituted with a halogen atom or a heteroatom-containing group. For example, some of the hydrogen atoms constituting the alkyl group may be substituted with a halogen atom or a heteroatom-containing group. Furthermore, some of the carbon atoms (e.g., methylene groups) constituting the alkyl group may be substituted with a heteroatom-containing group. Examples of heteroatoms include oxygen, sulfur, and nitrogen atoms. Examples of heteroatom-containing groups include (-O-), -C(=O)-O-, -OC(=O)-, -C(=O)-, -OC(=O)-O-, -C(=O)-NH-, -NH-, -S-, -S(=O)2-, and -S(=O)2-O-.

[0090] 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 Among these, monocyclic alicyclic hydrocarbon groups are preferred, and specifically, cyclopentyl and cyclohexyl groups are more preferred.

[0091] 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 (alicyclic 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 101 ~Ra 103 In the formula (I), 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 101 ~Ra 103 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 101 ~Ra 103 Among these, from the viewpoint of ease of synthesis, a hydrogen atom or a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms is preferred, and among these, a hydrogen atom, a methyl group, or an ethyl group is more preferred, with a hydrogen atom being particularly preferred.

[0092] The above Ra 101 ~Ra 103 Examples of the substituents that the chain saturated hydrocarbon group or the aliphatic cyclic saturated hydrocarbon group represented by the formula: x5 The same groups as those shown below can be mentioned.

[0093] Ra 101~Ra 103 Examples of the group containing a carbon-carbon double bond formed by two or more of the above being bonded to each other 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. Among these, from the viewpoint of ease of synthesis, a cyclopentenyl group, a cyclohexenyl group, and a cyclopentylidene-ethenyl group are preferred.

[0094] 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 alicyclic hydrocarbon group are preferably monocyclic or polycyclic groups of the formula: In formula (a1-r2-3), Ra 104 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. 104 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.

[0095] Ra in formula (a1-r2-3) 104 Examples of the substituent that may be possessed by include a methyl group, an ethyl group, a propyl group, a hydroxyl group, a carboxyl group, a halogen atom, an alkoxy group (such as a methoxy group, an ethoxy group, a propoxy group, or a butoxy group), and an alkyloxycarbonyl group.

[0096] In formula (a1-r2-4), Ra' 12 and Ra' 13 are each independently a monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms. 12 and Ra' 13In the formula, the monovalent chain saturated hydrocarbon group having 1 to 10 carbon atoms includes the above-mentioned Ra 101 ~Ra 103 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 x5 The same groups as those shown below can be mentioned.

[0097] 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.

[0098] 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.

[0099] Ra' 14 The 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.

[0100] Ra'14 When is a cyclic hydrocarbon group, the hydrocarbon group may be an alicyclic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The alicyclic 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 is preferably one having 7 to 12 carbon atoms, specific examples of which include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0101] Ra' 14 As the aromatic hydrocarbon group in 104 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 104 Examples of the substituents include the same as those that may be possessed by the group.

[0102] 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) 14When 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.

[0103] Specific examples of the group represented by the formula (a1-r2-1) are listed below.

[0104] [ka]

[0105] [ka]

[0106] [ka]

[0107] Specific examples of the group represented by the formula (a1-r2-2) are listed below.

[0108] [ka]

[0109] [ka]

[0110] [ka]

[0111] Specific examples of the group represented by the formula (a1-r2-3) are listed below.

[0112] [ka]

[0113] Specific examples of the group represented by the formula (a1-r2-4) are listed below.

[0114] [ka]

[0115] 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").

[0116] [ka] [In the formula, Ra' 7 ~Ra' 9 are each alkyl groups.

[0117] In formula (a1-r-3), Ra' 7 ~Ra' 9 are each 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.

[0118] Secondary 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-4).

[0119] [ka] [In the formula, Ra' 10 is a hydrocarbon group. 11a and Ra' 11b are each independently a hydrogen atom, a halogen atom or an alkyl group. 12is a hydrogen atom or a hydrocarbon group. 10 and Ra' 11a or Ra' 11b and may be bonded to each other to form a ring. 11a or Ra' 11b and Ra' 12 may be bonded to each other to form a ring.

[0120] In the formula, Ra' 10 and Ra' 12 The hydrocarbon group in Ra' 3 The same can be mentioned. In the formula, Ra' 11a and Ra' 11b The alkyl group in Ra' is 1 The alkyl groups in the above formula (I) are the same as those in the above formula (I). In the formula, Ra' 10 and Ra' 12 The hydrocarbon group in 11a and Ra' 11b The alkyl group in may have a substituent. Examples of the substituent include the above-mentioned Ra x5 etc.

[0121] Ra' 10 and Ra' 11a or Ra' 11b may be bonded to each other to form a ring, which may be a polycyclic ring, a monocyclic ring, an alicyclic ring, or an aromatic ring. The alicyclic and aromatic rings may contain heteroatoms.

[0122] Ra' 10 and Ra' 11a or Ra' 11b Among the above, the ring formed by bonding to each other is preferably a monocycloalkene, a ring in which some of the carbon atoms of a monocycloalkene are substituted with heteroatoms (oxygen atoms, sulfur atoms, etc.), or a monocycloalkadiene, more preferably a cycloalkene having 3 to 6 carbon atoms, and more preferably cyclopentene or cyclohexene.

[0123] Ra' 10 and Ra' 11a or Ra' 11b The ring formed by bonding these may be a fused ring. Specific examples of such a fused ring include indan.

[0124] Ra' 10 and Ra' 11a or Ra' 11b The ring formed by bonding together may have a substituent. Examples of the substituent include the above-mentioned Ra x5 etc.

[0125] Ra' 11a or Ra' 11b and Ra' 12 and may be bonded to each other to form a ring, and the ring may include Ra' 10 and Ra' 11a or Ra' 11b and the ring formed by bonding with each other are exemplified.

[0126] Specific examples of the group represented by the formula (a1-r-4) are listed below.

[0127] [ka]

[0128] 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.

[0129] 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).

[0130] [ka] [wherein R is 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), (a1-r-2) or (a1-r-4). 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).

[0131] 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. As the halogen atom, a fluorine atom is 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.

[0132] In the formula (a1-1), Va 1The divalent hydrocarbon group in may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0133] 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.

[0134] 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.

[0135] 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. A preferred monocyclic alicyclic hydrocarbon group is 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. A preferred polycyclic alicyclic hydrocarbon group is a group in which two hydrogen atoms have been removed from a polycycloalkane, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0136] 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.

[0137] In the formula (a1-1), Ra 1 is an acid-dissociable group represented by the above formula (a1-r-1) or (a1-r-2).

[0138] In the formula (a1-2), Wa 1 n in a2The 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.

[0139] 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).

[0140] Specific examples of the structural unit (a1) are shown below. In each of the following formulas, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0141] [ka]

[0142] [ka]

[0143] [ka]

[0144] [ka]

[0145] [ka]

[0146] [ka]

[0147] [ka]

[0148] [ka]

[0149] 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 properties (CDU, etc.) in lithography using electron beams or EUV.

[0150] [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). * represents a bond.

[0151] 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 general formula (a1-r2-1), (a1-r2-3), or (a1-r2-4) is as described above. Among these, it is preferable to select an acid-dissociable group that is a cyclic group, since this is suitable for use with EB or EUV and can enhance reactivity.

[0152] When the component (A1) contains the structural unit (a1), the proportion of the structural unit (a1) in the component (A1) is preferably 1 to 30 mol %, more preferably 1 to 20 mol %, and even more preferably 1 to 10 mol %, relative to 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, CDU, 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.

[0153] Building block (a5): In this embodiment, the structural unit (a5) is a structural unit that generates acid upon exposure, and any known structural unit can be used. By including the structural unit (a5), the acid generated upon exposure tends to be more uniformly distributed within the resist film. Suitable examples of the structural unit (a5) include structural units represented by general formula (a5-1) shown below.

[0154] [ka] [In the formula, R m is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a halogen atom, or a hydrogen atom. 1 is a divalent linking group or a single bond. 050 is a divalent hydrocarbon group which may have a substituent. a5 is an integer between 0 and 2. 0 is a divalent linking group. 0 is a divalent linking group which may have a heteroatom, or a single bond. 051 and Ra 052 are each independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group, n0 is an integer of 1 to 4, m is an integer of 1 or more, and M' m+ is an m-valent onium cation.

[0155] {anion part} In the above formula (a5-1), R m is an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a halogen atom, or a hydrogen atom. R m The alkyl group having 1 to 5 carbon atoms 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 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, an iodine atom, etc. As the halogen atom in the halogenated alkyl group, a fluorine atom is particularly preferred. R m 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.

[0156] In the above formula (a5-1), La 1 is a divalent linking group or a single bond. La 1 The divalent linking group in the formula 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, and each of these groups is the same as those described above for Ya x1 The divalent linking group is the same as the optionally substituted divalent hydrocarbon group and the divalent linking group containing a hetero atom exemplified in the above. Among the above, La 1 is preferably an ester bond [-C(=O)-O-, -OC(=O)-], an ether bond (-O-), a linear or branched alkylene group, an aromatic hydrocarbon group, or a combination thereof, or a single bond. 1is more preferably an ester bond [-C(=O)-O-, -OC(=O)-] or a single bond, and further preferably an ester bond [-C(=O)-O-, -OC(=O)-].

[0157] In the above formula (a5-1), Ra 050 is a divalent hydrocarbon group which may have a substituent. Ra 050 The divalent hydrocarbon group in may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

[0158] ··Ra 050 Aliphatic hydrocarbon groups in The aliphatic hydrocarbon group means 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.

[0159] 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.

[0160] 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.

[0161] 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 obtained by removing two hydrogen atoms 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.

[0162] 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 most 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 most preferably a methoxy group or an ethoxy group. Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferred. 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-.

[0163] ··Ra 050 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, even 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 substituents. 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. Specific examples of the aromatic hydrocarbon group include groups (arylene groups or heteroarylene groups) in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle; 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 (aryl group or heteroaryl group) in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle 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.

[0164] 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 most 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.

[0165] n a5 is an integer between 0 and 2 inclusive. Among the above, Ra 050 is preferably an aliphatic hydrocarbon group containing a ring in its structure, more preferably a cyclic aliphatic hydrocarbon group which may contain a substituent containing a hetero atom in the ring structure, and even more preferably an alicyclic hydrocarbon group which is a polycyclic group or a monocyclic group and which may have a substituent. Or, among the above, Ra 050 is preferably an aromatic hydrocarbon group.

[0166] n a5 If is 2, then two Ra 050 may all be alicyclic hydrocarbon groups which may have a substituent, may all be aromatic hydrocarbon groups, or may be a combination of alicyclic hydrocarbon groups which may have a substituent and aromatic hydrocarbon groups.

[0167] In the above formula (a5-1), La 0 is a divalent linking group. La 0 Examples of the divalent linking group in the formula (I) include non-hydrocarbon oxygen-atom-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-atom-containing linking groups with alkylene groups. A sulfonyl group (-SO2-) may be further linked to this combination. Examples of such divalent linking groups include linking groups represented by the following general formulae (L-al-1) to (L-al-8): In the following general formulae (L-al-1) to (L-al-8), Ra in the above formula (a5-1) 050 The bond to V' in the following general formulas (L-al-1) to (L-al-8) is 101 is.

[0168] [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.

[0169] V' 102 The 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.

[0170] 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' 102Specific 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.

[0171] La 0 As for L-al-1, a divalent linking group containing an ester bond or a divalent linking group containing an ether bond is preferable, the linking groups represented by the above formulas (L-al-1) to (L-al-5) and (L-al-8) are more preferable, and the linking group represented by (L-al-3) or (L-al-8) is even more preferable.

[0172] In the formula (a5-1), Ya 0 is a divalent linking group which may have a heteroatom, or a single bond. Ya 0The 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 0 The divalent hydrocarbon group which may have a substituent and the divalent linking group which contains a hetero atom in x1 The divalent linking group is the same as the optionally substituted divalent hydrocarbon group and the divalent linking group containing a hetero atom exemplified in the above. Among the above, Ya 0 is preferably a linear or branched alkylene group or a single bond, and more preferably a single bond.

[0173] In the above formula (a5-1), Ra 051 and Ra 052 are each independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group. Ra 051 and Ra 052 The fluorinated alkyl group in each of the above is preferably a linear or branched fluorinated alkyl group having 1 to 5 carbon atoms, more preferably a trifluoromethyl group. In the above formula (a5-1), SO3 - Ra bonded to the carbon atom adjacent to 051 and Ra 052 From the viewpoint of acid strength, it is preferable that at least one of the groups is a fluorine atom.

[0174] In the formula (a5-1), n0 represents an integer of 1 to 4, and 1, 2, or 3 is preferable.

[0175] {cation part} In the above formula (a5-1), M' m+ represents an m-valent onium cation. Among these, M' m+ is preferably a sulfonium cation or an iodonium cation, and m is an integer of 1 or more.

[0176] Preferred cationic moieties ((M' m+ ) 1 / m) includes organic cations represented by the following general formulas (ca-1) to (ca-3), respectively.

[0177] [ka] [In the formula, R 201 ~R 207 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 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-.]

[0178] In the above general formulas (ca-1) to (ca-3), R 201 ~R 207 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 The alkyl group in the formula (I) is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. R 201 ~R 207 The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms. R 201 ~R 207 , and R 210 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).

[0179] [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.

[0180] 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.

[0181] 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, this number of carbon atoms does not include the number of carbon atoms in the substituent. R' 201 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' 201Specific 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.

[0182] 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.

[0183] Among them, R' 201The 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.

[0184] 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.

[0185] Also, R' 201The cyclic hydrocarbon group in may contain a heteroatom, such as a heterocycle, etc. Specific examples include the lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) above, the —SO2-containing cyclic groups represented by the general formulae (b5-r-1) to (b5-r-4) above, and other heterocyclic groups represented by the chemical formulae (r-hr-1) to (r-hr-16) above.

[0186] 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.

[0187] A chain alkyl group which may have a substituent: 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.

[0188] 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.

[0189] 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:

[0190] 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.

[0191] 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 (b5-r-1) to (b5-r-4) is preferred.

[0192] In the above general formulas (ca-1) to (ca-3), R 201 ~R 203 , R 206 ~R 207 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 )-(applicable R N is 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 dibenzothiophene ring, a 9H-thioxanthene ring, a thioxanthone ring, a thianthrene ring, a phenoxathiin ring, a tetrahydrothiophenium ring, and a tetrahydrothiopyranium ring.

[0193] 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.

[0194] 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 the formula (I) 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 (b5-r-1), an "-SO2- containing polycyclic group" is preferred, and a group represented by the above general formula (b5-r-1) is more preferred.

[0195] Specific examples of the cation represented by the formula (ca-1) are shown below.

[0196] Specific examples of suitable cations represented by the formula (ca-1) include cations represented by the following chemical formulas.

[0197] [ka]

[0198] [ka]

[0199] [ka] [In the formula, g1, g2, and g3 represent the number of repeating units, where g1 is an integer of 1 to 5, g2 is an integer of 0 to 20, and g3 is an integer of 0 to 20.]

[0200] [ka]

[0201] [ka]

[0202] [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

[0203] [ka]

[0204] Specific examples of suitable cations represented by the formula (ca-2) include diphenyliodonium cation, bis(4-tert-butylphenyl)iodonium cation, and the like.

[0205] 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).

[0206] [ka]

[0207] The cation moiety ((M' m+ ) 1 / m ) is preferably a sulfonium cation, more preferably a cation represented by each of the formulas (ca-1) to (ca-3), still more preferably a cation represented by the formula (ca-1), and particularly preferably a cation represented by each of the formulas (ca-1-1) to (ca-1-3).

[0208] Specific preferred examples of the structural unit (a5) are shown below. In the following formula, R αrepresents a hydrogen atom, a methyl group, or a trifluoromethyl group. m+ represents m and M' in the above general formula (a5-1). m+ is the same as:

[0209] [ka]

[0210] [ka]

[0211] [ka]

[0212] The structural unit (a5) 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 (a5), the proportion of the structural unit (a5) in the component (A1) is preferably 1 to 20 mol %, more preferably 2 to 15 mol %, and even more preferably 3 to 10 mol %, based on the total (100 mol %) of all structural units constituting the component (A1). When the proportion of the structural unit (a5) is at least as large as the lower limit of the above-mentioned preferred range, it becomes easier to achieve even higher sensitivity and improved resolution, while when it is at most the upper limit of the above-mentioned preferred range, it becomes easier to achieve a balance with other structural units.

[0213] Regarding the structural unit (a2): The component (A1) may further include a structural unit (a2) that includes a lactone-containing cyclic group (provided that this does not fall under the category of structural unit (a1)). The lactone-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.

[0214] 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).

[0215] [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, or a lactone-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. * represents a bond (the same applies hereinafter).

[0216] 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 The halogen atom in is preferably a fluorine atom. 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.

[0217] Ra' 21 In the -COOR" and -OC(=O)R" groups, R" is a hydrogen atom, an alkyl group, or a lactone-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. 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 In the above formula, at least one hydrogen atom of the alkyl group is substituted with a hydroxyl group.

[0218] Ra' 21 Among the above, each of the groups is preferably independently a hydrogen atom or a cyano group.

[0219] 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 straight-chain or branched-chain 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.

[0220] Specific examples of the groups represented by the general formulae (a2-r-1) to (a2-r-7) are listed below.

[0221] [ka]

[0222] [ka]

[0223] 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).

[0224] [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. 21is -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.

[0225] 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.

[0226] 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.

[0227] 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.

[0228] In the formula (a2-1), Ya 21 is a single bond, and La 21 is preferably —COO— or —OCO—.

[0229] In the above formula (a2-1), Ra 21 is a lactone-containing cyclic group. Ra 21 Suitable examples of the lactone-containing cyclic group in the formula (a2-r-1) include the groups represented by the general formulae (a2-r-1) to (a2-r-7) described above.

[0230] 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 20 mol%, more preferably 1 to 15 mol%, and even more preferably 1 to 10 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.

[0231] Regarding the structural unit (a8): The structural unit (a8) is a structural unit derived from a compound represented by the following general formula (a8-1). However, those that fall under the structural unit (a0) are excluded.

[0232] [ka] [In the formula, W 2 is a polymerizable group-containing group. x2 is a single bond or (n ax2 +1)valent linking group. x2 and W 2 R may form a condensed ring. 1 R is a fluorinated alkyl group having 1 to 12 carbon atoms. 2 R is a hydrogen atom or an organic group having 1 to 12 carbon atoms which may have a fluorine atom. 2 and Ya x2 may be bonded to each other to form a ring structure. ax2 is an integer between 1 and 3.

[0233] W 2 The "polymerizable group" in the polymerizable group-containing group is a group that enables a compound having a polymerizable group to be polymerized by radical polymerization or the like, and refers to a group that contains a multiple bond between carbon atoms, such as an ethylenic double bond.

[0234] The polymerizable group-containing group may be a group consisting of only a polymerizable group, or may be a group consisting of a polymerizable group and a group other than the polymerizable group. Examples of the group other than the polymerizable group include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a heteroatom. Examples of the polymerizable group-containing group include a group represented by the chemical formula: C(R X11 )(R X12 )=C(R X13 )-Ya x0 A group represented by the formula - is preferred. In this chemical formula, R X11 , R X12 and R X13 are each a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and Ya x0 is a single bond or a divalent linking group.

[0235] Ya x2 and W 2 The fused ring formed by W 2 Polymerizable group of the site and Ya x2 and W 2 Other groups than the polymerizable group at the Ya site x2 and a fused ring formed by Ya x2 and W 2 The fused ring formed by these may have a substituent.

[0236] Specific examples of the structural unit (a8) are shown below. In the following formula, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0237] [ka]

[0238] Among the above examples, the structural unit (a8) is preferably at least one selected from the group consisting of structural units represented by chemical formulas (a8-1-01) to (a8-1-04), (a8-1-06), (a8-1-08), (a8-1-09), and (a8-1-10), and more preferably at least one selected from the group consisting of structural units represented by chemical formulas (a8-1-01) to (a8-1-04) and (a8-1-09).

[0239] The structural unit (a8) contained in the component (A1) may be of one type, or may be of two or more types. The amount of the structural unit (a8) in the component (A1) is preferably no more than 50 mol %, and more preferably 0 to 30 mol %, relative to the total amount (100 mol %) of all structural units constituting the component (A1).

[0240] The component (A1) contained in the resist composition may be a single compound, or a combination of two or more compounds. However, it is preferable that the component (A1) contains a copolymer having at least the structural unit (a01), the structural unit (a02), and the structural unit (a10).

[0241] Examples of the component (A1) include a polymeric compound having the structural unit (a01), the structural unit (a02), and the structural unit (a10); a polymeric compound having the structural unit (a01), the structural unit (a02), and the structural unit (a10), and a polymeric compound having the structural unit (a5). Preferred examples of the component (A1) include a polymeric compound comprising the structural unit (a01), the structural unit (a02), and the structural unit (a10); a polymeric compound having the structural unit (a01), the structural unit (a02), and the structural unit (a10), and a polymeric compound having the structural unit (a5).

[0242] In a polymeric compound composed of the structural unit (a01), the structural unit (a02), and the structural unit (a10), the proportion of the structural unit (a01) relative to the total (100 mol%) of all structural units constituting the polymeric compound is preferably 15 to 45 mol%, more preferably 20 to 40 mol%, and even more preferably 25 to 35 mol%. The proportion of the structural unit (a02) in the polymer compound is preferably 15 to 45 mol %, more preferably 20 to 40 mol %, and even more preferably 25 to 35 mol %, based on the total (100 mol %) of all structural units constituting the polymer compound. The proportion of the structural unit (a10) in the polymer compound is preferably 35 to 65 mol %, more preferably 40 to 60 mol %, and even more preferably 45 to 55 mol %, based on the total (100 mol %) of all structural units constituting the polymer compound. However, the total amount of the structural units (a01), (a02), and (a10) does not exceed 100 mol %.

[0243] In a polymeric compound comprising the structural unit (a5) and a polymeric compound having the structural unit (a01), the structural unit (a02), and the structural unit (a10), the proportion of the structural unit (a01) relative to the total (100 mol %) of all structural units constituting the polymeric compound is preferably 15 to 45 mol %, more preferably 20 to 40 mol %, and even more preferably 25 to 35 mol %. The proportion of the structural unit (a02) in the polymer compound is preferably 15 to 45 mol %, more preferably 20 to 40 mol %, and even more preferably 25 to 35 mol %, based on the total (100 mol %) of all structural units constituting the polymer compound. The proportion of the structural unit (a10) in the polymer compound is preferably 20 to 50 mol %, more preferably 25 to 45 mol %, and even more preferably 30 to 40 mol %, based on the total (100 mol %) of all structural units constituting the polymer compound. The proportion of the structural unit (a5) in the polymer compound is preferably 1 to 20 mol %, more preferably 2 to 15 mol %, and even more preferably 3 to 10 mol %, based on the total (100 mol %) of all structural units constituting the polymer compound. However, the total amount of the structural units (a01), (a02), (a10), and (a5) does not exceed 100 mol %.

[0244] 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 (a01), a monomer that derives the structural unit (a02), a monomer that derives the structural unit (a10), and, if necessary, a monomer that derives a structural unit other than the structural unit (a01), the structural unit (a02), and the structural unit (a10) (for example, the structural unit (a5)) in a polymerization solvent, adding the above-mentioned radical polymerization initiator to the solution to cause polymerization, 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).

[0245] 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 less than or equal to the preferred upper limit of this range, the compound has sufficient solubility in a resist solvent for use as a resist, and when it is at least the preferred lower limit of this range, the compound exhibits good dry etching resistance and the 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.

[0246] About ingredient (A2) The resist composition of this embodiment may also use, as the component (A), a base component (hereafter referred to as “component (A2)”) that does not fall under the category of the component (A1) and whose solubility in a developer changes upon the action of an acid. There are no particular restrictions on the component (A2), and it can be selected from the many conventional base components for chemically amplified resist compositions. The component (A2) may be a high molecular weight compound or a low molecular weight compound, and may be used alone or in combination of two or more types.

[0247] The proportion of the component (A1) within the component (A), relative to the total mass of the component (A), is preferably 25 mass% or more, more preferably 50 mass% or more, even more preferably 75 mass% or more, and may even be 100 mass%. When this proportion is 25 mass% or more, a resist pattern that is excellent in various lithography properties, such as high sensitivity, resolution, and improved roughness, is more likely to be formed.

[0248] 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.

[0249] <Other ingredients> The resist composition of this embodiment may further contain other components in addition to the component (A). Examples of other components include the following components (B), (D), (E), (F), and (S).

[0250] <Acid generator component (B)> The resist composition of this embodiment preferably further contains an acid generator 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.

[0251] 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)").

[0252] 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)").

[0253] [ka] [In the formula, R 101 and R 104 ~R 108 R each independently 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. 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, provided that Y 101 and V 101 cannot be a single bond at the same time. 101 ~L102 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.

[0254] {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.

[0255] 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 is preferably saturated.

[0256] 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 101Specific 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, benzyl group, phenethyl group, 1-naphthylmethyl 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.

[0257] R 101 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.

[0258] Among them, R 101The 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, further preferably an adamantyl group or a norbornyl group, and particularly preferably an adamantyl group.

[0259] 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.

[0260] Also, R 101The 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) above, -SO2- containing cyclic groups represented by the general formulae (b5-r-1) to (b5-r-4) below, and other heterocyclic groups represented by the chemical formulae (r-hr-1) to (r-hr-16) below. In the formula, * represents Y in formula (b-1). 101 represents a bond bonded to

[0261] [ka] [In the formula, Rb' 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, or an -SO2- containing cyclic group; B" 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. * represents a bond.

[0262] In the general formulae (b5-r-1) and (b5-r-2), B″ represents 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. B" 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 even more preferably a methylene group.

[0263] In the general formulae (b5-r-1) to (b5-r-4), Rb' 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, and among these, are preferably each independently a hydrogen atom or a cyano group.

[0264] Specific examples of the groups represented by general formulae (b5-r-1) to (b5-r-4) are listed below, in which "Ac" represents an acetyl group.

[0265] [ka]

[0266] [ka]

[0267] [ka]

[0268] [ka]

[0269] 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. 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, a bromine atom, or an iodine 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.

[0270] 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

[0271] [ka]

[0272] 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 (b5-r-1) to (b5-r-4) above; and heterocyclic groups represented by the formulae (r-hr-7) to (r-hr-16) above.

[0273] 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. 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.

[0274] An optionally substituted chain alkenyl group: R 101The 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.

[0275] 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:

[0276] 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 the divalent linking group containing an oxygen atom include linking groups represented by the following general formulae (y-al-1) to (y-al-7): In the following general formulae (y-al-1) to (y-al-7), R 101 The bond to V' in the following general formulas (y-al-1) to (y-al-7) is 101 is.

[0277] [ka] [In the formula, V' 101 is a single bond or an alkylene group having 1 to 5 carbon atoms, and V' 102is a divalent saturated hydrocarbon group having 1 to 30 carbon atoms.

[0278] V' 102 The 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.

[0279] 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). 3A 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.

[0280] In formula (b-1), V 101 is a single bond, an alkylene group, or a fluorinated alkylene group. 101 is preferably a single bond or a linear fluorinated alkylene group having 1 to 4 carbon atoms.

[0281] 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.

[0282] 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).

[0283] [ka] [In the formula, R” 101 R" is an aliphatic cyclic group which may have a substituent, a monovalent heterocyclic group represented by 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), a chain alkyl group which may have a substituent, or an aromatic cyclic group which may have a substituent. 102R" 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 (b5-r-1) to (b5-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.

[0284] 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).

[0285] R” 101 and 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).

[0286] R” 101 The chain alkyl group which may have a substituent is R 101 The alkyl group is preferably one of the groups exemplified as the chain alkyl group in the above formula. R” 103 The 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.

[0287] 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.

[0288] 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—.

[0289] Among the above, the anion moiety of the component (B) is preferably the anion in the component (b-1), and more preferably the anion represented by the above formula (an-1).

[0290] {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. M' in the formula (b-1), formula (b-2) and formula (b-3) m+ As the group, M' in the formula (a5-1) m+ is the same as:

[0291] Among the above, the cation moiety of component (B) is preferably a sulfonium cation, more preferably the cations represented by the formulas (ca-1) to (ca-3), still more preferably the cation represented by the formula (ca-1), and particularly preferably the cations represented by the formulas (ca-1-1) to (ca-1-83).

[0292] 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. Within the resist composition, the amount of the component (B) per 100 parts by mass of the component (A) is preferably less than 50 parts by mass, and more preferably from 10 to 40 parts by mass. By ensuring that the amount of component (B) falls within this 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.

[0293] When the component (A1) has a repeating structure of the structural unit (a5), the amount of the component (B) in the resist composition is preferably less than 50 parts by mass, more preferably 0 to 40 parts by mass, and even more preferably 0 to 30 parts by mass, per 100 parts by mass of the component (A).

[0294] <Base component (D)> In addition to the component (A), the resist composition of this embodiment may further contain a base component (component (D)) that traps the acid generated upon exposure (i.e., controls the diffusion of the acid). The component (D) acts as a quencher (acid diffusion controller) that traps the 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.

[0295] 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.

[0296] [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.

[0297] {(d1-1) component} Anion part In formula (d1-1), Rd 1 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, and each of the R' 201 The same can be mentioned. Among these, Rd 1is preferably 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. Examples of the substituent 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 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 via an alkylene group, and in this case, the substituent is preferably a linking group represented by the above formulas (y-al-1) to (y-al-5). Note that Rd 1 When the aromatic hydrocarbon group, the aliphatic cyclic group, or the chain alkyl group in the formula (d3-1) has a linking group represented by the general formulas (y-al-1) to (y-al-7) as a substituent, in the general formulas (y-al-1) to (y-al-7), Rd 1 The carbon atom constituting the aromatic hydrocarbon group, the aliphatic cyclic group, or the chain alkyl group in the formula (y-al-1) to (y-al-7) is bonded to V' 101 is. 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.

[0298] 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.

[0299] Preferred examples of the anion moiety of the component (d1-1) are shown below.

[0300] [ka]

[0301] Cation part In formula (d1-1), M m+ is an m-valent organic cation. M m+ Suitable organic cations include those similar to those represented by the general formulae (ca-1) to (ca-5), with the cation represented by the general formula (ca-1) being more preferred, and the cations represented by the general formulae (ca-1-1) to (ca-1-83) being even more preferred. The component (d1-1) may be used alone or in combination of two or more.

[0302] {(d1-2) component} Anion part In formula (d1-2), Rd 2 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, and R' 201 The same can be mentioned. However, Rd 2In 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, 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, etc.; or a group in which one or more hydrogen atoms have been removed from camphor, etc. 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.

[0303] Preferred examples of the anion moiety of the component (d1-2) are shown below.

[0304] [ka]

[0305] 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.

[0306] {(d1-3) component} Anion part In formula (d1-3), Rd 3is 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 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.

[0307] In formula (d1-3), 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, and R' 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. 4 A 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.

[0308] Road 4 The alkenyl group in R' 201 Examples include the same alkenyl groups as those in the above, and vinyl, propenyl (allyl), 1-methylpropenyl, and 2-methylpropenyl groups are 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.

[0309] 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.

[0310] 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. 21 Examples 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.

[0311] Preferred examples of the anion moiety of the component (d1-3) are shown below.

[0312] [ka]

[0313] [ka]

[0314] 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.

[0315] 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) in the resist composition is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 2 to 8 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.

[0316] 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.

[0317] 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. An 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 6 to 30 carbon atoms are more preferred, and tri-n-pentylamine or tri-n-octylamine is particularly preferred.

[0318] 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 is preferably one having 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.

[0319] 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.

[0320] 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, N-tert-butoxycarbonylpyrrolidine, and 2,6-di-tert-butylpyridine.

[0321] 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.

[0322] <<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. Specific examples of organic carboxylic acids include acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, and salicylic acid, with salicylic acid being preferred. 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) per 100 parts by mass of the component (A) is preferably 0.01 to 5 parts by mass, and more preferably 0.05 to 3 parts by mass. By ensuring that the amount is within this range, the sensitivity, lithography properties, and the like are improved.

[0323] <Fluorine additive component (F)> The resist composition of this embodiment may contain a fluorine additive component (hereafter referred to as "component (F)") as a hydrophobic resin. Component (F) is used to impart water repellency to the resist film, and when used as a resin separate from component (A), it can 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, 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), a structural unit derived from acrylic acid or methacrylic acid, and the structural unit (a1), more preferably a copolymer of the structural unit (f1) with 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, and more preferably a structural unit derived from 1-ethyl-1-cyclooctyl(meth)acrylate.

[0324] [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.

[0325] 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 in Rf include the same alkyl groups having 1 to 5 carbon atoms as those in R, and a methyl group or an ethyl group is preferred. 102 and Rf 103 Specific 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, more preferably a hydrogen atom, a fluorine atom, a methyl group, or an ethyl group, and even more preferably a hydrogen atom. 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.

[0326] 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 101is 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.

[0327] 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.

[0328] In the resist composition of this embodiment, the component (F) may be used alone, or in combination of two or more different compounds. When the resist composition contains the component (F), the amount of the component (F) is preferably 0.5 to 10 parts by mass, and more preferably 1 to 10 parts by mass, per 100 parts by mass of the component (A).

[0329] <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 to be conventionally used as solvents for chemically amplified resist compositions can be used. 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.

[0330] Furthermore, a mixed solvent of PGMEA and a polar solvent is also preferred as component (S), and the blending ratio (mass ratio) may be appropriately determined taking into consideration the compatibility between PGMEA and the polar solvent, etc. 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 %.

[0331] 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.

[0332] 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.

[0333] The resist composition of the present embodiment described above contains a resin component (A1) having a structural unit (a01) represented by general formula (a01), a structural unit (a02) represented by general formula (a02), and a structural unit (a10) represented by general formula (a10-1). The structural unit (a01) has an unsaturated bond within the ring structure at the end of its side chain, and the structural unit (a02) has a saturated bond within the ring structure at the end of its side chain. Furthermore, the ring structure at the end of the side chain of the structural unit (a01) is similar to the ring structure at the end of the side chain of the structural unit (a02). Therefore, the structural unit (a02), which is difficult to deprotect, at the boundary between the exposed and unexposed regions makes it difficult for dissolution contrast to occur due to energy absorption, thereby improving LWR performance. Furthermore, in the unexposed regions, the structural unit (a01), which contains an unsaturated bond in the ring, increases solubility in the developer, thereby suppressing film loss (DL) and improving etching resistance. Furthermore, because the component (A1) contains the structural unit (a10), it functions as a proton source in exposed areas, thereby achieving high sensitivity. It is presumed that the combined effects described above enable the resist composition of this embodiment to achieve high sensitivity and further improve resolution when forming a resist pattern.

[0334] (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 according to the first aspect of the present invention, 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.

[0335] 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 ArF exposure device, either through a mask (mask pattern) on which a predetermined pattern has been formed, or by direct irradiation with an electron beam 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.

[0336] 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.

[0337] 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.

[0338] The wavelength used for exposure is not particularly limited, and radiation such as ArF excimer laser, KrF excimer laser, F2 excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-rays, and soft X-rays can be used.

[0339] 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, such as water, a fluorine-based inert liquid, a silicon-based solvent, or a hydrocarbon-based solvent. As the immersion medium, water is preferably used.

[0340] An example of an alkaline developer used in the development treatment in the alkaline development process is 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.

[0341] Examples of ester-based solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, pentyl acetate, isopentyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl 3-ethoxypropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate, butyl butanoate, methyl 2-hydroxyisobutyrate, isoamyl acetate, isobutyl isobutyrate, and butyl propionate.

[0342] Examples of nitrile solvents include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

[0343] If necessary, known additives such as surfactants can be added to the organic developer.

[0344] 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).

[0345] The organic solvent contained in the rinse solution used in the rinsing treatment after development in the solvent development process can be selected appropriately from the organic solvents listed above as organic solvents used in the organic developer, so long as it does not easily dissolve the resist pattern. Typically, at least one solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents is used. These organic solvents may be used alone or in combination of two or more, and may be used in combination with other organic solvents or water.

[0346] 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).

[0347] The resist composition of the above-described embodiment and the various materials used in the method of forming a resist pattern of the above-described embodiment (e.g., resist solvent, developer, rinse solution, composition for forming an anti-reflective film, composition for forming a top coat, etc.) preferably do not contain impurities such as metals, metal salts containing halogen, acids, alkalis, or components containing sulfur atoms or phosphorus atoms. Here, examples of impurities containing metal atoms include Na, K, Ca, Fe, Cu, Mn, Mg, Al, Cr, Ni, Zn, Ag, Sn, Pb, Li, or salts thereof. The content of impurities contained in these materials is preferably 200 ppb or less, more preferably 1 ppb or less, even more preferably 100 ppt (parts per trillion) or less, particularly preferably 10 ppt or less, and most preferably substantially none (below the detection limit of the measuring device).

[0348] According to the resist pattern forming method of the present embodiment described above, the resist composition described above is used, so that it is possible to form an excellent resist pattern that has high sensitivity, reduced LWR, high etching resistance, and suppressed film loss (DL) due to the developer.

[0349] <Polymer compounds> The polymeric compound of this embodiment comprises the structural unit (a01), the structural unit (a02), and the structural unit (a10). That is, the polymeric compound of this embodiment is similar to the resin component (A1) of the first aspect, and is useful as a base resin for a resist composition. [Example]

[0350] The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

[0351] The structures of the polymer compounds (A1-1) to (A1-9) and the polymer compounds (A2-1) to (A2-2) are shown below: In each formula, l, m, and n represent the composition ratio of each structural unit.

[0352] [Table 1]

[0353] [ka]

[0354] [ka]

[0355] [ka]

[0356] <Preparation of Resist Composition> (Examples 1 to 12, Comparative Examples 1 to 3) The components shown in Table 2 were mixed and dissolved to prepare the resist compositions of the respective examples.

[0357] [Table 2]

[0358] In Table 2, the abbreviations have the following meanings: The numbers in brackets [ ] are the blend amounts (parts by mass). (A1)-1 to (A1)-9: The above polymer compounds (A1-1) to (A1-9). (A2-1)~(A2-3): The above-mentioned polymer compounds (A2-1)~(A2-3).

[0359] (B)-1: An acid generator comprising a compound represented by the following chemical formula (B-1). (B)-2: An acid generator comprising a compound represented by the following chemical formula (B-2). (B)-3: An acid generator comprising a compound represented by the following chemical formula (B-3).

[0360] [ka]

[0361] (D)-1: An acid diffusion controller comprising a compound represented by the following chemical formula (D1-1). (D)-2: An acid diffusion controller comprising a compound represented by the following chemical formula (D1-2). (S)-1: A mixed solvent of propylene glycol monomethyl ether acetate / cyclohexanone (2240:960) (mass ratio).

[0362] [ka]

[0363] <Evaluation> A line and space resist pattern (LS pattern) was formed by the resist pattern formation method described below, and the sensitivity, etching resistance, and film loss (DL) were evaluated.

[0364] <<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 50 nm. Next, the resist film was subjected to exposure (writing) 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. Thereafter, post-exposure baking (PEB) was performed at 100° 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, in all examples, a 1:1 LS pattern with a line width of 50 nm was formed.

[0365] [Evaluation of optimal exposure (Eop)] The optimum exposure dose Eop (μC / cm2) for forming an LS pattern of the target size using the resist pattern forming method described above was determined. The results are shown in Table 3 as "Eop (μC / cm2)."

[0366] [Evaluation of etching resistance] Each resist film prepared in the above <Resist Pattern Formation> before exposure (after PAB) was subjected to a dry etching process with CF4 gas for 60 seconds using a dry etching apparatus TCA-3822 (Tokyo Ohka Kogyo Co., Ltd.). The thickness of the resist film before and after the dry etching process was measured, and the etching residual film ratio was calculated using the following formula. The results are shown in Table 3 as "Etching residual film ratio (%)." The remaining film rate (%) was calculated as follows: [film thickness after etching treatment / film thickness before etching treatment]×100. The closer the residual film rate (%) is to 100, the higher the etching resistance is.

[0367] [Evaluation of film loss (DL)] In the above <Formation of Resist Pattern>, the thickness of the resist film immediately after PAB treatment and the thickness of the unexposed part of the resist film after water rinsing were measured, and the amount of film thickness reduction was measured. The results are shown in Table 3 as "DL (nm)".

[0368] [Evaluation of LWR (Line Width Roughness)] The LS pattern formed in the above <Formation of Resist Pattern> was measured for 3σ, which is a measure of LWR. The results are shown in Table 3 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.

[0369] [Table 3]

[0370] The results shown in Table 2 confirm that the resist compositions of Examples 1 to 12, to which the present invention was applied, were all excellent in sensitivity, LWR, etching resistance, and film loss (DL), compared to Comparative Examples 1 to 3, which are outside the scope of the present invention. In the resist composition to which the present invention is applied, (A1) which has a structural unit (a01) containing an endocyclic unsaturated bond and a structural unit (a02) similar in structure to the structural unit (a01) and containing an endocyclic saturated bond, improves LWR performance by preventing dissolution contrast from occurring due to energy absorption by the structural unit (a02), which is difficult to deprotect, at the boundary between exposed and unexposed areas.Furthermore, in the unexposed areas, the solubility in the developer is increased by the structural unit (a01) containing an endocyclic unsaturated bond, thereby suppressing film loss (DL) and improving etching resistance.It is estimated that the resist compositions of Examples 1 to 12 have better sensitivity, etching resistance, film loss (DL), and etching resistance than Comparative Examples 1 to 3.

[0371] Ra in the general formula (a01) 01 is an alkyl group and Ra in the general formula (a02) 02 In Example 6, which used the polymer compound (A1-6) in which is an isopropyl group, the sensitivity, LWR, DL suppression, and etching resistance were superior to those of Examples 1 to 5. In Examples 10 to 12, in which an acid generator or an acid diffusion controller containing an iodine atom was used, the sensitivity and DL suppression were superior to those in Examples 1 to 9.

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, Contains a resin component (A1) whose solubility in a developer changes under the action of an acid, The resin component (A1) has a structural unit (a01) represented by the following general formula (a01), a structural unit (a02) represented by the following general formula (a02), and a structural unit (a10) represented by the following general formula (a10-1): 【Chemistry 1】 [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. n a11 represents 0 or 1. Ra ０１ is hydrogen or a linear or branched alkyl group; and n a12 is 1 or 2. 【Chemistry 2】 [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. na21 represents 0 or 1. Ra ０２ is a linear or branched alkyl group. na22 is 1 or 2. 【Transformation 3】 [Wherein W is a polymerizable group-containing group. ｘ０ represents an aromatic hydrocarbon group which may have a substituent; and nax0 represents an integer of 1 or more.

2. In the general formula (a01), Ra ０１ 2. The resist composition according to claim 1, wherein is a methyl group.

3. In the general formula (a02), Ra ０２ 2. The resist composition according to claim 1, wherein is an isopropyl group.

4. 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.

5. A polymeric compound having a structural unit (a01) represented by the following general formula (a01), a structural unit (a02) represented by the following general formula (a02), and a structural unit (a10) represented by the following general formula (a10-1): 【Chemistry 4】 [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. n a11 represents 0 or 1. Ra ０１ is hydrogen or a linear or branched alkyl group; and n a12 is 1 or 2. 【Transformation 5】 [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. na21 represents 0 or 1. Ra ０２ is a linear or branched alkyl group. na22 is 1 or 2. 【Transformation 6】 [Wherein W is a polymerizable group-containing group. ｘ０ represents an aromatic hydrocarbon group which may have a substituent; and nax0 represents an integer of 1 or more.

6. In the general formula (a01), Ra ０１ The polymer compound according to claim 5 , wherein is a methyl group.

7. In the general formula (a02), Ra ０２ The polymer compound according to claim 5 , wherein is an isopropyl group.

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