Radiation-sensitive resin composition, pattern forming method, and water-repellent improving agent

Abstract

Provided are: a radiation-sensitive resin composition which exhibits good sensitivity and can form a resist pattern having high water repellency and few defects; and a resist pattern formation method and a water repellency-improving agent using same.　This radiation-sensitive resin composition contains a resin A having a first structural unit containing a partial structure represented by formula (1). In formula (1), X is a divalent linking group.　R1 and R2 are each independently a monovalent chain-like hydrocarbon group having 1-40 carbon atoms, a monovalent alicyclic hydrocarbon group having 3-20 carbon atoms, a monovalent aromatic hydrocarbon group having 6-12 carbon atoms, or a monovalent fluorinated hydrocarbon group having 1-40 carbon atoms, or R1 and R2 bond to each other to form a 3- to 20-membered ring structure (a) together with the carbon atom to which these are bonded.　R3 is a fluorinated chain-like hydrocarbon group having 1-4 carbon atoms.　＊ denotes a position of linking to a polymer main chain.　The radiation-sensitive resin composition also contains: resin B containing a structural unit having an acid-dissociable group; a radiation-sensitive acid generator; and a solvent.

Description

[Technical Field]

[0001] The present invention relates to a radiation-sensitive resin composition, a method for forming a resist pattern using the same, and a water-repellency improving agent, etc. [Background technology]

[0002] With the miniaturization of various electronic device structures such as semiconductor devices and liquid crystal devices, further miniaturization of resist patterns in the lithography process is required, and for this reason, various radiation-sensitive resin compositions are being investigated. Such radiation-sensitive resin compositions generate acid in the exposed areas when irradiated with radiation such as far ultraviolet light from an ArF excimer laser or electron beams. The catalytic action of this acid creates a difference in the dissolution rate in the developer between the exposed and unexposed areas, thereby forming a resist pattern on the substrate.

[0003] In such radiation-sensitive resin compositions, liquid immersion lithography is used as a method to form even finer resist patterns, for example, with a line width of about 45 nm. In this method, exposure is performed with the exposure light path space (between the lens and the resist film) filled with an immersion medium that has a higher refractive index (n) than air or an inert gas, such as pure water or a fluorine-based inert liquid. Therefore, even when the numerical aperture (NA) of the lens is increased, the depth of focus does not decrease easily, and high resolution can be obtained.

[0004] In immersion lithography, resin compositions use hydrophobic polymer additives made of fluorine atoms to enhance the hydrophobicity of the resist film surface. These additives suppress the elution of acid generators and other substances from the formed resist film into the immersion medium, preventing deterioration of the resist film performance and contamination of lenses and other equipment. They also improve the water drainage of the resist film surface, preventing watermarks and enabling high-speed scanning (see, for example, Patent Document 1). However, increasing the hydrophobicity of the resist film surface reduces its wettability to developers and rinse solutions. This can lead to insufficient removal of development residue deposited in unexposed areas of the resist film surface during development, potentially causing defects such as blob defects in the resist pattern. To suppress the occurrence of such defects, fluorine atom-containing polymers that are hydrophobic during immersion lithography but hydrophilic during alkaline development have been proposed. Specifically, polymers incorporating a fluoroalkyl ester structure of a carboxylic acid have been introduced (see, for example, Patent Document 2). It is believed that using such polymers as hydrophobic polymer additives can suppress the occurrence of defects. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2007 / 116664 [Patent Document 2] Japanese Patent Publication No. 2010-32994 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, with the miniaturization of resist patterns progressing to a level of line width of 45 nm or less, the required level of defect suppression has become even higher. Furthermore, the water-repellent polymer additive is also required to enhance the sensitivity performance of the radiation-sensitive resin composition containing it, thereby enabling the acquisition of highly accurate patterns with a high yield. However, conventional radiation-sensitive resin compositions have not been able to satisfy these requirements.

[0007] The present invention aims to provide a radiation-sensitive resin composition that exhibits good sensitivity and can form a resist pattern with high water repellency and few defects, a method for forming a resist pattern using the same, and a water repellency improving agent, etc. [Means for solving the problem]

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

[0009] For example, in one embodiment, the present invention A resin A having a first structural unit including a substructure represented by the following formula (1), [ka] (In formula (1), X is a divalent linking group. R 1 and R 2 Each of these independently consists of a monovalent linear hydrocarbon group having 1 to 40 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, a monovalent fluorinated hydrocarbon group having 1 to 40 carbon atoms, or R 1 and R 2 These are combined with each other to form a ring structure (a) with 3 to 20 member atoms, along with the carbon atoms to which they are bonded. R 3 This is a fluorinated chain hydrocarbon group having 1 to 4 carbon atoms. * indicates the linkage site with the polymer main chain. Resin B containing a structural unit having an acid-dissociable group, Radiation-sensitive acid generator, and solvent This invention relates to a radiation-sensitive resin composition containing [a specific substance].

[0010] The radiation-sensitive resin composition of the present invention, because it contains the above-mentioned resin A, exhibits good sensitivity and enables the formation of a resist pattern with high water repellency and few defects. The above-mentioned resin A is mainly -C(=O)OCR 1 R 2 R 3 The excellent water repellency and water stability of the area suggest that it contributes to the high water repellency and defect suppression of the resist pattern. However, this inference of the mechanism of action does not necessarily limit the scope of the present invention.

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

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

[0013] On the other hand, in another embodiment, the present invention states that A step of forming a resist film by directly or indirectly applying the above radiation-sensitive resin composition onto a substrate. The process of exposing the above-mentioned resist film by immersion lithography, A method for forming a resist pattern, including a step of developing the exposed resist film, is provided.

[0014] Since the method for forming a resist pattern of the present invention includes a step using the above-described radiation-sensitive resin composition, it has good sensitivity, and it is possible to obtain a resist pattern having high water repellency and few defects.

[0015] On the other hand, in another embodiment, the present invention relates to a water repellency improver including a resin A having a first structural unit represented by the following formula (2). [Chemical formula] [[ID=~17]](In formula (2), X is a divalent linking group. [[ID=~21]]R is a hydrogen atom, a fluorine atom, or a monovalent hydrocarbon group which is unsubstituted or substituted with a halogen atom or an alkoxy group. R 1 and R​​​​​​​​​​​​​​​​​​​​​​​​​​The radiation-sensitive resin composition according to this embodiment (hereinafter also simply referred to as "the composition") comprises a predetermined resin A, resin B, a radiation-sensitive acid generator, and a solvent. The composition may also contain other optional components as long as they do not impair the effects of the present invention. By containing the predetermined resin A, the radiation-sensitive resin composition can form a resist pattern with good sensitivity, high water repellency, and few defects.

[0019] (Resin A) Resin A is a resin having a first structural unit that includes a substructure represented by the above formula (1).

[0020] In formula (1) above, the divalent linking group represented by X can be, for example, a divalent hydrocarbon group having 1 to 20 carbon atoms, a divalent fluorinated hydrocarbon group having 1 to 20 carbon atoms, or a group in which one or more carbon atoms in these groups are replaced by a divalent group such as -O-, -CO-, -COO-, -CONR'-, -S-, -CS-, -COS, -CSO-, etc. R' is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms.

[0021] In the above formula (1), the above R 1 and R 2 The chain-like hydrocarbon groups having 1 to 40 carbon atoms represented by the formula can be, independently, linear or branched saturated hydrocarbon groups having 1 to 40 carbon atoms, or linear or branched unsaturated hydrocarbon groups having 1 to 40 carbon atoms.

[0022] In the above formula (1), the above R 1 and R 2 Examples of monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, represented by the formula, include, independently, cyclopropyl group, cyclobutyl group, cyclopentyl group, and cyclohexyl group.

[0023] In the above formula (1), the above R 1 and R 2Examples of monovalent aromatic hydrocarbon groups having 6 to 12 carbon atoms, represented by the formula, include, independently, aryl groups such as phenyl, tolyl, xyl, naphthyl, and anthyl groups; and aralkyl groups such as benzyl, phenethyl, and naphthylmethyl groups.

[0024] In the above formula (1), the above R 1 and R 2 Examples of monovalent fluorinated hydrocarbon groups having 1 to 40 carbon atoms, represented by the formula, include, independently, monovalent fluorinated linear hydrocarbon groups having 1 to 40 carbon atoms and monovalent fluorinated alicyclic hydrocarbon groups having 3 to 40 carbon atoms.

[0025] In the above formula (1), the above R 1 and R 2 Examples of ring structures (a) with 3 to 20 members, formed by combining these with the carbon atoms to which they are bonded, include alicyclic hydrocarbons with the above number of carbon atoms, or groups obtained by removing two hydrogen atoms from the same carbon atom in a structure in which one or more carbon atoms in an alicyclic hydrocarbon are replaced by divalent groups such as -O-, -CO-, -COO-, -CONR'-, -S-, -CS-, -COS, -CSO-, etc.

[0026] In the above formula (1), the above R 3 Examples of fluorinated chain hydrocarbon groups having 1 to 4 carbon atoms, such as monovalent fluorinated chain hydrocarbon groups having 1 to 4 carbon atoms and monovalent fluorinated alicyclic hydrocarbon groups having 3 to 4 carbon atoms, can be found.

[0027] Examples of the above monovalent fluorinated chain hydrocarbon groups having 1 to 4 carbon atoms include, for example, Fluorinated alkyl groups such as trifluoromethyl group, 2,2,2-trifluoroethyl group, pentafluoroethyl group, 2,2,3,3,3-pentafluoropropyl group, 1,1,1,3,3,3-hexafluoropropyl group, and heptafluoron-propyl group; Fluorinated alkenyl groups such as trifluoroethenyl groups and pentafluoropropenyl groups; Examples include fluorinated alkynyl groups such as fluoroethynyl groups and trifluoropropynyl groups.

[0028] Examples of the above-mentioned monovalent fluorinated alicyclic hydrocarbon groups having 3 to 4 carbon atoms include, Examples include fluorinated cycloalkyl groups such as fluorocyclobutyl groups.

[0029] In formula (1) above, * indicates a linkage site with the polymer main chain, and it is preferable that it is a covalent bond.

[0030] The above-mentioned first structural unit (hereinafter also referred to as "structural unit (1)") is preferably a structural unit represented by the following formula (2). [ka] (In formula (2), X and R 1 ~R 3 This is the same as equation (1). R is a hydrogen atom, a fluorine atom, or a monovalent hydrocarbon group that is unsubstituted or substituted with a halogen atom or an alkoxy group.

[0031] In formula (2) above, the unsubstituted or monovalent hydrocarbon group represented by R, which is substituted with a halogen atom or an alkoxy group, is preferably a hydrogen atom or a methyl group, and more preferably a methyl group, from the viewpoint of copolymerizability of the monomer containing the first structural unit.

[0032] In the above-mentioned first structural unit, it is preferable that X in formula (2) is a group represented by the following formula (2-1). [ka] (In formula (2-1), Z 1 and Z 2Each of these independently consists of a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group, a monovalent fluorinated hydrocarbon group, a group in which one or more carbon atoms are replaced by a linking group represented by *-O-*, *-CO-*, *-COO-*, or *-OCO-* (where * in the above linking group represents a bond with a carbon atom), or Z 1 and Z 2 These are ring structures with 3 to 20 members, formed by combining them with the carbon atoms to which they bond. L is a single bond or a divalent organic group. n is an integer between 1 and 5.

[0033] In the above equation (2-1), Z 1 and Z 2 Examples of monovalent hydrocarbon groups represented by these symbols include, independently, a methyl group and an ethyl group.

[0034] In the above equation (2-1), Z 1 and Z 2 Examples of monovalent fluorinated hydrocarbon groups represented by include, independently, monovalent fluorinated hydrocarbon groups having 1 to 10 carbon atoms.

[0035] In the above equation (2-1), the above Z 1 and Z 2 Examples of monovalent fluorinated hydrocarbon groups having 1 to 10 carbon atoms, as represented by this formula, include monovalent fluorinated linear hydrocarbon groups having 1 to 10 carbon atoms and monovalent fluorinated alicyclic hydrocarbon groups having 3 to 10 carbon atoms.

[0036] Examples of the above monovalent fluorinated chain hydrocarbon group having 1 to 10 carbon atoms include, for example, Fluorinated alkyl groups such as trifluoromethyl group, 2,2,2-trifluoroethyl group, pentafluoroethyl group, 2,2,3,3,3-pentafluoropropyl group, 1,1,1,3,3,3-hexafluoropropyl group, and heptafluoron-propyl group; Fluorinated alkenyl groups such as trifluoroethenyl groups and pentafluoropropenyl groups; Examples include fluorinated alkynyl groups such as fluoroethynyl groups and trifluoropropynyl groups.

[0037] Examples of the above-mentioned monovalent fluorinated alicyclic hydrocarbon groups having 3 to 10 carbon atoms include: Fluorinated cycloalkyl groups such as fluorocyclopentyl group, difluorocyclopentyl group, nonafluorocyclopentyl group, fluorocyclohexyl group, difluorocyclohexyl group, undecafluorocyclohexylmethyl group, fluoronorbornyl group, fluoroadamantyl group, fluorobornyl group, and fluoroisobornyl group; Examples include fluorinated cycloalkenyl groups such as fluorocyclopentenyl groups and nonafluorocyclohexenyl groups.

[0038] The above-mentioned fluorinated hydrocarbon group is preferably a monovalent fluorinated linear hydrocarbon group having 1 to 10 carbon atoms, more preferably a monovalent fluorinated alkyl group having 1 to 8 carbon atoms, even more preferably a perfluoroalkyl group having 1 to 6 carbon atoms, and particularly preferably a linear perfluoroalkyl group having 1 to 6 carbon atoms.

[0039] In the above equation (2-1), Z 1 and Z 2 Examples of groups in which one or more carbon atoms in a monovalent fluorinated hydrocarbon group represented by *-O-* are replaced by linking groups represented by *-O-* include, independently, methoxymethyl groups and the like.

[0040] In the above equation (2-1), Z 1 and Z 2 Examples of groups in which one or more carbon atoms in a monovalent fluorinated hydrocarbon group represented by *-CO-* are replaced by a linking group represented by *-CO-* include, independently, acetyl groups and the like.

[0041] In the above equation (2-1), Z 1 and Z 2Examples of groups in which one or more carbon atoms in a monovalent fluorinated hydrocarbon group represented by *-COO-* are replaced by a linking group represented by *-COO-* include, independently, a methoxycarbonyl group and an ethoxycarbonyl group.

[0042] In the above equation (2-1), Z 1 and Z 2 Examples of groups in which one or more carbon atoms in a monovalent fluorinated hydrocarbon group represented by *-OCO-* are replaced by a linking group represented by *-OCO-* include, independently, a methyl carbonate group.

[0043] In the above equation (2-1), the above Z 1 and Z 2 The ring structure (b) having 3 to 20 members, formed by combining these with the carbon atoms to which they are bonded, is not particularly limited as long as it is a group obtained by removing two hydrogen atoms from the same carbon atom constituting the carbon ring of the hydrocarbon with the above number of carbon atoms.

[0044] In formula (2-1) above, the divalent organic group represented by L is, for example, a substituted or unsubstituted divalent hydrocarbon group having 1 to 30 carbon atoms, with -O-, -S-, -CO-, -COO-, and -NR between the carbon-carbon bonds of the hydrocarbon group. 20 -, -CONR 20 - A divalent group having the following (R 20 Examples include a hydrogen atom or a monovalent hydrocarbon group (the same applies hereinafter), a divalent heterocyclic group, etc.

[0045] In the above formula (2-1), n ​​is an integer between 1 and 5, but it is preferably between 2 and 3.

[0046] Examples of the first structural units include structural units represented by the following formulas (F-1) to (F-34) (hereinafter also referred to as "structural units (F-1) to (F-34)").

[0047] [ka] TIFF0007848693000006.tif202120TIFF0007848693000007.tif214145TIFF0007848693000008.tif111130

[0048] The content of the first structural unit in the above resin A is preferably 10 mol% or more, more preferably 20 mol% or more, relative to the total structural units constituting the above resin A. It may also be 100 mol%, preferably 90 mol% or less, and more preferably 80 mol% or less.

[0049] The above resin A may further have a second structural unit represented by the following formula (3) (hereinafter also referred to as "structural unit (2)"). [ka] (In formula (3), R 4 This is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 5 It is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R 6 and R 7 Each of these is independently a monovalent linear hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R 6 and R 7 These are divalent alicyclic groups with 3 to 20 carbon atoms, formed by combining them with the carbon atoms to which they are bonded.

[0050] In the above equation (3), R 5 Examples of monovalent hydrocarbon groups having 1 to 20 carbon atoms, represented by this formula, include methyl groups and ethyl groups.

[0051] In the above equation (3), R 6 and R 7 Examples of monovalent chain hydrocarbon groups having 1 to 10 carbon atoms, represented by the formula, include, independently, a methyl group and an ethyl group.

[0052] In the above equation (3), R 6 and R 7 Examples of monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, represented by the formulas, include, independently, cyclopentyl groups and cyclohexyl groups.

[0053] In the above equation (3), R 6 and R 7 The divalent alicyclic group having 3 to 20 carbon atoms, which is formed when these are combined with each other and bonded together with the carbon atoms, is not particularly limited as long as it is a group obtained by removing two hydrogen atoms from the same carbon atom that constitutes the carbon ring of the hydrocarbon with the above number of carbon atoms.

[0054] Examples of the second structural unit include the structural units represented by the following formulas (2-1) to (2-6) (hereinafter also referred to as "structural units (2-1) to (2-6)").

[0055] [ka]

[0056] In the above equations (2-1) to (2-6), R 4 ~R 7 This is equivalent to equation (2) above. i and j are independent integers between 0 and 16. k is between 0 and 1.

[0057] i and j are preferably 1. 5 A methyl group, an ethyl group, or an isopropyl group is preferred.

[0058] The resin A described above may contain one or more structural units (2) in combination.

[0059] When a second structural unit is included, the content of the second structural unit in the resin A is preferably 1 mol% or more, more preferably 5 mol% or more, relative to the total structural units constituting the resin A. Furthermore, 70 mol% or less is preferred, and 60 mol% or less is more preferred.

[0060] (Method of synthesizing resin A) The above-mentioned resin A can be synthesized, for example, by polymerizing monomers that give each structural unit in a suitable solvent using a radical polymerization initiator or the like.

[0061] Examples of the radical polymerization initiators mentioned above include azo-based radical polymerization initiators such as azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and dimethyl-2,2'-azobisisobutyrate; and peroxide-based radical polymerization initiators such as benzoyl peroxide, t-butyl hydroperoxide, and cumene hydroperoxide. Among these, AIBN and dimethyl-2,2'-azobisisobutyrate are preferred, with AIBN being more preferred. These radical polymerization initiators can be used individually or in combination of two or more.

[0062] Examples of solvents used in the polymerization described above include Alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane; Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, and norbornane; Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, and cumene; Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, and chlorobenzene; Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate, and methyl propionate; Ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone, and 2-heptanone; Ethers such as tetrahydrofuran, dimethoxyethanes, and diethoxyethanes; Examples of solvents include methanol, ethanol, 1-propanol, 2-propanol, 4-methyl-2-pentanol, and other alcohols. The solvent used in these polymerizations may be used alone or in combination of two or more.

[0063] The reaction temperature in the above polymerization is typically 40°C to 150°C, with 50°C to 120°C being preferred. The reaction time is typically 1 hour to 48 hours, with 1 hour to 24 hours being preferred.

[0064] The molecular weight of resin A is not particularly limited, but the polystyrene-based weight-average molecular weight (Mw) determined by gel permeation chromatography (GPC) is preferably 1,000 to 50,000, more preferably 2,000 to 30,000, even more preferably 3,000 to 15,000, and particularly preferably 4,000 to 12,000. If the Mw of resin A is below the lower limit, the heat resistance of the resulting resist film may decrease. If the Mw of resin A exceeds the upper limit, the developability of the resist film may decrease.

[0065] The ratio of Mw to the polystyrene-equivalent number-average molecular weight (Mn) (Mw / Mn) of resin A, as determined by GPC, is usually between 1 and 5, preferably between 1 and 3, and more preferably between 1 and 2.

[0066] The Mw and Mn values ​​of resin A described above are measured using gel permeation chromatography (GPC) under the following conditions.

[0067] GPC columns: 2 x G2000HXL, 1 x G3000HXL, 1 x G4000HXL (all manufactured by Tosoh Corporation) Column temperature: 40℃ Leaching solvent: Tetrahydrofuran Flow rate: 1.0mL / min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0068] The content of resin A is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, even more preferably 1 part by mass or more, and particularly preferably 1.5 parts by mass or more, per 100 parts by mass of the base resin. Furthermore, it is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, even more preferably 10 parts by mass or less, and particularly preferably 8 parts by mass or less.

[0069] (Resin B) Resin B is a resin containing a structural unit having an acid-dissociable group (hereinafter, this resin is also referred to as the "base resin"). Resin B is an aggregate of polymers having a structural unit containing an acid-dissociable group (hereinafter, also referred to as "structural unit (I)"). An "acid-dissociable group" is a group that substitutes a hydrogen atom, such as a carboxyl group, phenolic hydroxyl group, alcoholic hydroxyl group, or sulfo group, and dissociates upon the action of an acid. The radiation-sensitive resin composition exhibits excellent pattern-forming properties because the above resin contains structural unit (I).

[0070] The base resin preferably has structural unit (II) in addition to structural unit (I), which includes at least one selected from the group consisting of lactone structures, cyclic carbonate structures, and sultone structures, as described later, and may also have other structural units other than structural units (I) and (II). Each structural unit will be described below.

[0071] [Structural Unit (I)] Structural unit (I) is a structural unit containing an acid-dissociable group. Structural unit (I) is not particularly limited as long as it contains an acid-dissociable group, and examples include a structural unit having a tertiary alkyl ester moiety, a structural unit having a structure in which the hydrogen atom of a phenolic hydroxyl group is replaced by a tertiary alkyl group, and a structural unit having an acetal bond. However, from the viewpoint of improving the pattern-forming properties of the radiation-sensitive resin composition, a structural unit represented by the following formula (4) (hereinafter also referred to as "structural unit (I-1)") is preferred.

[0072] [ka] (In formula (4), R 8 This is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 9 It is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R 10 and R 11 Each of these is independently a monovalent linear hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R 10 and R 11 These are divalent alicyclic groups with 3 to 20 carbon atoms, formed by combining them with the carbon atoms to which they are bonded.

[0073] In the above equation (4), R 9 Examples of monovalent hydrocarbon groups having 1 to 20 carbon atoms, represented by this formula, include methyl groups and ethyl groups.

[0074] In the above equation (4), R 10 and R 11 Examples of monovalent chain hydrocarbon groups having 1 to 10 carbon atoms, represented by the formula, include, independently, a methyl group and an ethyl group.

[0075] In the above formula (4), RR 10 and R 11 Examples of monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, represented by the formulas, include, independently, cyclopentyl groups and cyclohexyl groups.

[0076] In the above equation (4), R 10 and R 11 The divalent alicyclic group having 3 to 20 carbon atoms, which is formed when these are combined with each other and bonded together with the carbon atoms, is not particularly limited as long as it is a group obtained by removing two hydrogen atoms from the same carbon atom that constitutes the carbon ring of the hydrocarbon with the above number of carbon atoms.

[0077] Examples of structural units (I-1) include the structural units represented by the following formulas (4-1) to (4-6) (hereinafter also referred to as "structural units (I-1-1) to (I-1-6)").

[0078] [ka]

[0079] In the above equations (4-1) to (4-6), R 8 ~R 11 This is equivalent to equation (4) above. i' and j' are independent integers between 0 and 16. k' is between 0 and 1.

[0080] i' and j' are preferably 1. 9 A methyl group, an ethyl group, or an isopropyl group is preferred.

[0081] The base resin may contain one or more structural units (I) in combination.

[0082] The content of structural unit (I) (total content if multiple types are included) is preferably 10 mol% or more, more preferably 20 mol% or more, even more preferably 30 mol% or more, and particularly preferably 35 mol% or more, relative to the total structural units constituting the base resin. Furthermore, it is preferably 80 mol% or less, more preferably 75 mol% or less, even more preferably 70 mol% or less, and particularly preferably 65 mol% or less. By setting the content of structural unit (I) within the above range, the pattern-forming properties of the radiation-sensitive resin composition can be further improved.

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

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

[0085]

Chemical formula

[0086] In the above formulas, R L1 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R L2 to R L5 [ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a cyano group, a trifluoromethyl group, a methoxy group, a methoxycarbonyl group, a hydroxy group, a hydroxymethyl group, or a dimethylamino group. R L4 and R L5 may be a divalent alicyclic group having 3 to 8 carbon atoms formed together with the carbon atoms to which they are attached. L 2 is a single bond or a divalent linking group. X is an oxygen atom or a methylene group. k is an integer of 0 to 3. m is an integer of 1 to 3.

[0087] Examples of the divalent alicyclic group having 3 to 8 carbon atoms formed by combining the above R L4 and R L5 together with the carbon atoms to which they are attached include R 1 and R 2Examples include divalent alicyclic groups with 3 to 8 carbon atoms, which are formed by combining chain-like hydrocarbon groups or alicyclic hydrocarbon groups represented by the formula, together with the carbon atoms to which they are bonded. One or more hydrogen atoms on this alicyclic group may be substituted with hydroxyl groups.

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

[0089] Among these, structural units (II) are preferably those containing a lactone structure, more preferably those containing a norbornane lactone structure, and even more preferably those derived from norbornane lactone-yl (meth)acrylate.

[0090] The content of structural unit (II) is preferably 20 mol% or more, more preferably 25 mol% or more, and even more preferably 30 mol% or more, relative to the total structural units constituting the base resin. Furthermore, it is preferably 80 mol% or less, more preferably 75 mol% or less, and even more preferably 70 mol% or less. By setting the content of structural unit (II) within the above range, the radiation-sensitive resin composition can further improve lithography performance such as resolution and the adhesion of the formed resist pattern to the substrate.

[0091] [Structural Unit (III)] The base resin may optionally contain other structural units in addition to the structural units (I) and (II) described above. Examples of these other structural units include structural unit (III) containing a polar group (excluding those corresponding to structural unit (II)). By further containing structural unit (III), the solubility of the base resin in the developer can be adjusted, and as a result, the lithographic performance such as resolution of the radiation-sensitive resin composition can be improved. Examples of these polar groups include hydroxyl groups, carboxyl groups, cyano groups, nitro groups, sulfonamide groups, etc. Among these, hydroxyl groups and carboxyl groups are preferred, and hydroxyl groups are more preferred.

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

[0093] [ka]

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

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

[0096] [Structural Units (IV)] In addition to the structural unit (III) having the polar group, the base resin may optionally have a structural unit derived from hydroxystyrene or a structural unit having a phenolic hydroxyl group (hereinafter, both are collectively referred to as "structural unit (IV)") as other structural units. The structural unit (IV) contributes to the improvement of etching resistance and the improvement of the difference in developer solubility (dissolution contrast) between the exposed portion and the unexposed portion. In particular, it can be preferably applied to pattern formation using exposure with radiation having a wavelength of 50 nm or less, such as an electron beam or EUV. In this case, it is preferable that the resin has the structural unit (I) together with the structural unit (IV).

[0097] In this case, at the time of polymerization, it is preferable to carry out polymerization in a state where the phenolic hydroxyl group is protected by a protecting group such as an alkali dissociable group, and then perform hydrolysis to deprotect it so as to obtain the structural unit (IV). As the structural unit that gives the structural unit (IV) by hydrolysis, it is preferably represented by the following formulas (6-1) and (6-2).

[0098]

Chemical formula

[0099] [[ID=J15]] In the above formulas (6-1) and (6-2), R 13 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 12 is a monovalent hydrocarbon group or an alkoxy group having 1 to 20 carbon atoms. Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms of R 14 include the monovalent hydrocarbon group having 1 to 20 carbon atoms of R 8 in the structural unit (I). Examples of the alkoxy group include a methoxy group, an ethoxy group, and a tert-butoxy group. ]>

[0100] As the above R 14 an alkyl group and an alkoxy group are preferable, and among them, a methyl group and a tert-butoxy group are more preferable.

[0101] For resins used for exposure with radiation of wavelength 50 nm or less, the content of structural unit (IV) is preferably 10 mol% or more, more preferably 20 mol% or more, relative to the total structural units constituting the resin. Furthermore, it is preferably 70 mol% or less, and more preferably 60 mol% or less.

[0102] (Method of synthesizing resin B) The above-mentioned resin B can be synthesized, for example, by polymerizing monomers that give each structural unit in a suitable solvent using a radical polymerization initiator or the like.

[0103] Examples of the radical polymerization initiators mentioned above include azo-based radical polymerization initiators such as azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and dimethyl-2,2'-azobisisobutyrate; and peroxide-based radical polymerization initiators such as benzoyl peroxide, t-butyl hydroperoxide, and cumene hydroperoxide. Among these, AIBN and dimethyl-2,2'-azobisisobutyrate are preferred, with AIBN being more preferred. These radical polymerization initiators can be used individually or in combination of two or more.

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

[0105] The reaction temperature in the above polymerization is typically 40°C to 150°C, with 50°C to 120°C being preferred. The reaction time is typically 1 hour to 48 hours, with 1 hour to 24 hours being preferred.

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

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

[0108] The Mw and Mn values ​​of the base resin are measured using gel permeation chromatography (GPC), similar to the case of resin A described above.

[0109] The base resin content is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 85% by mass or more, relative to the total solid content of the radiation-sensitive resin composition.

[0110] (Other resins) The radiation-sensitive resin composition of this embodiment may also contain a resin with a higher mass content of fluorine atoms than the base resin (hereinafter also referred to as "high-fluorine content resin") as a resin other than resin A described above. When the radiation-sensitive resin composition contains a high-fluorine content resin, it can be unevenly distributed on the surface of the resist film relative to the base resin, and as a result, the water repellency of the surface of the resist film during immersion exposure can be improved.

[0111] The high-fluorine-content resin preferably has a structural unit represented by the following formula (7) (hereinafter also referred to as "structural unit (V)"), and may optionally have structural unit (I) or structural unit (II) of the base resin.

[0112] [ka]

[0113] In equation (7) above, R 15 This is a hydrogen atom, a methyl group, or a trifluoromethyl group. L R is a single bond, an oxygen atom, a sulfur atom, -COO-, -SO2ONH-, -CONH-, or -OCONH-. 16 This is a monovalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated alicyclic hydrocarbon group having 3 to 20 carbon atoms.

[0114] The above R 15 From the viewpoint of copolymerization of monomers that provide structural unit (V), hydrogen atoms and methyl groups are preferred, and methyl groups are more preferred.

[0115] The above G L From the viewpoint of copolymerization of monomers that provide structural unit (V), single bonds and -COO- are preferred, and -COO- is more preferred.

[0116] The above R 16Examples of monovalent fluorinated linear hydrocarbon groups having 1 to 20 carbon atoms, represented by , include those in which some or all of the hydrogen atoms in a linear or branched alkyl group having 1 to 20 carbon atoms are substituted with fluorine atoms.

[0117] The above R 16 Examples of monovalent fluorinated alicyclic hydrocarbon groups having 3 to 20 carbon atoms, represented by , include those in which some or all of the hydrogen atoms in a monocyclic or polycyclic hydrocarbon group having 3 to 20 carbon atoms are substituted with fluorine atoms.

[0118] The above R 16 Preferably, the group is a fluorinated chain hydrocarbon group, more preferably a fluorinated alkyl group, and even more preferably a 2,2,2-trifluoroethyl group, a 1,1,1,3,3,3-hexafluoropropyl group, and a 5,5,5-trifluoro-1,1-diethylpentyl group.

[0119] When a high-fluorine-content resin has structural units (V), the content of structural units (V) is preferably 30 mol% or more, more preferably 40 mol% or more, even more preferably 45 mol% or more, and particularly preferably 50 mol% or more, relative to the total structural units constituting the high-fluorine-content resin. Furthermore, it is preferably 95 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less. By setting the content of structural units (V) within the above range, the mass content of fluorine atoms in the high-fluorine-content resin can be more appropriately adjusted, further promoting the uneven distribution to the surface layer of the resist film, and as a result, the water repellency of the resist film during immersion exposure can be further improved.

[0120] High-fluorine content resins may have fluorine atom-containing structural units (hereinafter also referred to as structural unit (VI)) represented by the following formula (f-2), either together with or in place of structural unit (V). The presence of structural unit (f-2) in high-fluorine content resins improves solubility in alkaline developers and suppresses the occurrence of development defects.

[0121] [ka]

[0122] Structural units (VI) can be broadly classified into two types: (x) those having an alkali-soluble group, and (y) those having a group that dissociates upon the action of alkali, increasing its solubility in an alkaline developer (hereinafter also simply referred to as an "alkali-dissociable group"). In both (x) and (y), in the above formula (f-2), R C R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. D This is a single bond, a (s+1) valent hydrocarbon group with 1 to 20 carbon atoms, and the R of this hydrocarbon group E At the terminal end of the side are an oxygen atom, a sulfur atom, and -NR dd -, a structure to which a carbonyl group, -COO-, or -CONH- is bonded, or a structure in which some of the hydrogen atoms of this hydrocarbon group are replaced by an organic group having a heteroatom. dd is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. s is an integer from 1 to 3.

[0123] If structural unit (VI) has (x) an alkali-soluble group, R F is a hydrogen atom, A 1 * is an oxygen atom, -COO-* or -SO2O-*. F This shows the site of binding. 1 A is a single bond, a hydrocarbon group having 1 to 20 carbon atoms, or a divalent fluorinated hydrocarbon group. 1 If is an oxygen atom, then W 1 is A 1 It is a fluorinated hydrocarbon group having a fluorine atom or a fluoroalkyl group at the carbon atom to which it is bonded. E is a single bond or a divalent organic group with 1 to 20 carbon atoms. If s is 2 or 3, there are multiple R E , W 1 , A 1 and R F These may be the same or different. Having (x) an alkali-soluble group in structural unit (VI) increases its affinity for alkaline developer and suppresses development defects. A structural unit (VI) having (x) an alkali-soluble group is A 1is an oxygen atom and W 1 It is particularly preferable that the group is a 1,1,1,3,3,3-hexafluoro-2,2-methanediyl group.

[0124] If structural unit (VI) has an alkali-dissociable group (y), R F A is a monovalent organic group having 1 to 30 carbon atoms. 1 is an oxygen atom, -NR aa -, -COO-* or -SO2O-* aa * is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. F This shows the site of binding. 1 R is a single bond or a divalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. E A is a single bond or a divalent organic group having 1 to 20 carbon atoms. 1 If is -COO-* or -SO2O-*, then W 1 or R F is A 1 It has a fluorine atom on the carbon atom bonded to it or on an adjacent carbon atom. 1 If is an oxygen atom, then W 1 , R E It is a single bond, R D R is a hydrocarbon group with 1 to 20 carbon atoms. E It is a structure in which a carbonyl group is bonded to the terminal end, R F is an organic group containing a fluorine atom. When s is 2 or 3, multiple R E , W 1 , A 1 and R F These may be the same or different. The presence of (y) an alkali-dissociable group in structural unit (VI) causes the resist film surface to change from hydrophobic to hydrophilic during the alkali development process. As a result, the affinity for the developer is significantly increased, and development defects can be suppressed more efficiently. Examples of structural unit (VI) having (y) an alkali-dissociable group include A 1 is -COO-*, and R F Or W 1 Alternatively, it is particularly preferable that both of these contain fluorine atoms.

[0125] RC From the viewpoint of copolymerizability of the monomer that gives structural unit (VI), hydrogen atoms and methyl groups are preferred, and methyl groups are more preferred.

[0126] R E When the group is a divalent organic group, a group having a lactone structure is preferred, a group having a polycyclic lactone structure is more preferred, and a group having a norbornane lactone structure is even more preferred.

[0127] When a high-fluorine-content resin has structural units (VI), the content of structural units (VI) is preferably 50 mol% or more, more preferably 60 mol% or more, and even more preferably 70 mol% or more, relative to the total structural units constituting the high-fluorine-content resin. Furthermore, it is preferably 95 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less. By setting the content of structural units (VI) within the above range, the water repellency of the resist film during immersion exposure can be further improved.

[0128] [Other structural units] High-fluorine resins may also contain structural units having an alicyclic structure represented by the following formula (8), in addition to the structural units listed above. [ka] (In the above formula (8), R 1α R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 2α (It is a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms.)

[0129] In the above equation (8), R 2α Examples of monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, represented by , include those in which some or all of the hydrogen atoms in a monocyclic or polycyclic hydrocarbon group having 3 to 20 carbon atoms are substituted with fluorine atoms.

[0130] When a high-fluorine-content resin contains structural units having the above-mentioned alicyclic structure, the content of these structural units is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 30 mol% or more, relative to the total structural units constituting the high-fluorine-content resin. Furthermore, it is preferably 70 mol% or less, more preferably 60 mol% or less, and even more preferably 50 mol% or less.

[0131] The lower limit of Mw for the high-fluorine-content resin is preferably 1,000, more preferably 2,000, even more preferably 3,000, and particularly preferably 5,000. The upper limit of Mw is preferably 50,000, more preferably 30,000, even more preferably 20,000, and particularly preferably 15,000.

[0132] The lower limit of the Mw / Mn ratio for high-fluorine-content resins is usually 1, with 1.1 being more preferred. The upper limit of the above Mw / Mn ratio is usually 5, with 3 being preferred, 2 being more preferred, and 1.9 being even more preferred.

[0133] The content of the high-fluorine resin is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, even more preferably 1 part by mass or more, and particularly preferably 1.5 parts by mass or more, per 100 parts by mass of the base resin. Furthermore, it is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, even more preferably 10 parts by mass or less, and particularly preferably 8 parts by mass or less.

[0134] The radiation-sensitive resin composition may contain one or more high-fluorine-content resins.

[0135] (Method for synthesizing high-fluorine content resins) High-fluorine-content resins can be synthesized by the same method as the synthesis method for resin A or the base resin described above.

[0136] (Radiation-sensitive acid generator) The radiation-sensitive resin composition of this embodiment further comprises a radiation-sensitive acid generator that generates acid upon irradiation (exposure) with radiation. When the resin A has a base resin having structural unit (I) and also contains structural unit (2), the acid generated from the radiation-sensitive acid generator upon exposure can dissociate the acid-dissociable groups of structural unit (I) and structural unit (2), thereby generating carboxyl groups and the like.

[0137] The radiation-sensitive resin composition contains the above-mentioned radiation-sensitive acid generator, which increases the polarity of the resin in the exposed area. As a result, the resin in the exposed area becomes soluble in the developer in the case of alkaline aqueous solution development, while it becomes sparingly soluble in the developer in the case of organic solvent development.

[0138] Examples of radioactive acid generators include onium salt compounds, sulfonimide compounds, halogen-containing compounds, and diazoketone compounds. Examples of onium salt compounds include sulfonium salts, tetrahydrothiophenium salts, iodonium salts, phosphonium salts, diazonium salts, and pyridinium salts. Of these, sulfonium salts and iodonium salts are preferred.

[0139] Acids generated by exposure include those that produce sulfonic acids upon exposure. Examples of such acids include compounds in which one or more fluorine atoms or fluorinated hydrocarbon groups are substituted on carbon atoms adjacent to a sulfo group. Among these, those having a cyclic structure are particularly preferred as radiation-sensitive acid generators.

[0140] These radiation-sensitive acid generators may be used individually or in combination of two or more. The content of the radiation-sensitive acid generator (or the total content when multiple radiation-sensitive acid generators are used in combination) is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the base resin. Furthermore, it is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, even more preferably 30 parts by mass or less, and particularly preferably 20 parts by mass or less, per 100 parts by mass of the base resin. This allows for excellent sensitivity, LWR performance, and CDU performance during resist pattern formation.

[0141] (Acid diffusion control agent) The above radiation-sensitive resin composition may optionally contain an acid diffusion control agent. The acid diffusion control agent controls the diffusion phenomenon of acid generated from the radiation-sensitive acid generator in the resist film upon exposure, and has the effect of suppressing undesirable chemical reactions in the unexposed areas. In addition, the storage stability of the resulting radiation-sensitive resin composition is improved. Furthermore, the resolution of the resist pattern is further improved, and changes in the line width of the resist pattern due to variations in the holding time from exposure to development can be suppressed, resulting in a radiation-sensitive resin composition with excellent process stability.

[0142] Examples of acid diffusion control agents include compounds represented by the following formula (5) (hereinafter also referred to as "nitrogen-containing compounds (I)"), compounds having two nitrogen atoms in the same molecule (hereinafter also referred to as "nitrogen-containing compounds (II)"), compounds having three nitrogen atoms (hereinafter also referred to as "nitrogen-containing compounds (III)"), amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like.

[0143] [ka]

[0144] In the above equation (5), R 22 , R 23 and R 24Each of these is independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group.

[0145] Examples of nitrogen-containing compounds (I) include monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; trialkylamines such as triethylamine; and aromatic amines such as aniline.

[0146] Examples of nitrogen-containing compounds (II) include ethylenediamine and N,N,N',N'-tetramethylethylenediamine.

[0147] Examples of nitrogen-containing compounds (III) include polyamine compounds such as polyethyleneimine and polyallylamine; and polymers such as dimethylaminoethylacrylamide.

[0148] Examples of amide group-containing compounds include formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, benzamide, pyrrolidone, and N-methylpyrrolidone.

[0149] Examples of urea compounds include urea, methyl urea, 1,1-dimethyl urea, 1,3-dimethyl urea, 1,1,3,3-tetramethyl urea, 1,3-diphenyl urea, and tributylthiourea.

[0150] Examples of nitrogen-containing heterocyclic compounds include pyridines such as pyridine and 2-methylpyridine; morpholines such as N-propylmorpholine and N-(undecylcarbonyloxyethyl)morpholine; and pyrazines and pyrazoles.

[0151] Furthermore, compounds having an acid-dissociable group can also be used as the nitrogen-containing organic compound. Examples of such nitrogen-containing organic compounds having an acid-dissociable group include Nt-butoxycarbonylpiperidine, Nt-butoxycarbonylimidazole, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenzimidazole, N-(t-butoxycarbonyl)di-n-octylamine, N-(t-butoxycarbonyl)diethanolamine, N-(t-butoxycarbonyl)dicyclohexylamine, N-(t-butoxycarbonyl)diphenylamine, Nt-butoxycarbonyl-4-hydroxypiperidine, and Nt-amyloxycarbonyl-4-hydroxypiperidine.

[0152] Furthermore, a photodecayable base that generates a weak acid upon exposure can be suitably used as an acid diffusion control agent. Examples of photodecayable bases include compounds containing a radiation-sensitive onium cation that decomposes upon exposure and a weak acid anion. In the exposed area, a photodecayable base generates a weak acid from the proton produced by the decomposition of the radiation-sensitive onium cation and the weak acid anion, thus reducing its acid diffusion control capability.

[0153] Examples of photodecayable bases include sulfonium salt compounds represented by the following formula (6-1) and iodonium salt compounds represented by the following formula (6-2).

[0154] [ka]

[0155] In the above equations (6-1) and (6-2), J + It is a sulfonium cation, U + is an iodonium cation. A sulfonium cation or iodonium cation is preferably represented by the following formulas (X-1) to (X-6). E- and Q- are independently OH- and R α -COO - , R α -SO3- This is an anion represented by R. α R is an alkyl group, an aryl group, or an aralkyl group. α The hydrogen atoms of the aromatic ring of the aryl or aralkyl group represented by may be substituted with a hydroxyl group, a fluorine-substituted or unsubstituted C1-C12 alkyl group, or a C1-C12 alkoxy group.

[0156] [ka]

[0157] In the above equation (X-1), R a1 , R a2 and R a3 Each of these independently comprises a substituted or unsubstituted linear or branched alkyl group, alkoxy group or alkoxycarbonyloxy group having 1 to 12 carbon atoms, a substituted or unsubstituted monocyclic or polycyclic cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, a hydroxyl group, a halogen atom, and -OSO2-R. P , -SO2-R Q Alternatively, -SR T This represents a ring structure formed by combining two or more of these groups. This ring structure may contain heteroatoms such as O or S between the carbon-carbon bonds that form the skeleton. P , R Q and R T Each of these is independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k1, k2, and k3 are each independently integers from 0 to 5. a1 ~R a3 R P , R Q and R T If each of them is multiple, then multiple R a1 ~R a3 R P , R Q and R TThese may be the same or different.

[0158] In the above equation (X-2), R b1 This is a substituted or unsubstituted linear or branched alkyl or alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted acyl group having 2 to 8 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms, or a hydroxyl group. k n is either 0 or 1. k When is 0, k4 is an integer from 0 to 4, and n k When is 1, k4 is an integer from 0 to 7. b1 If there are multiple, then multiple R b1 They may be the same or different, and there may be multiple R b1 R may represent a ring structure formed by combining with other elements. b2 This is a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. C k5 is a single bond or a divalent linking group. k5 is an integer from 0 to 4. b2 If there are multiple, then multiple R b2 They may be the same or different, and there may be multiple R b2 may represent a ring structure formed by combining with each other. q is an integer between 0 and 3. In the formula, S + The ring structure containing may include heteroatoms such as O and S between the carbon-carbon bonds that form the skeleton.

[0159] In the above equation (X-3), R c1 , R c2 and R c3 Each of these is independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms.

[0160] In the above equation (X-4), R g1 This is a substituted or unsubstituted linear or branched alkyl or alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted acyl group having 2 to 8 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms, or a hydroxyl group.k n is either 0 or 1. k2 When k10 is 0, k10 is an integer from 0 to 4, and n k2 When k10 is 1, k10 is an integer from 0 to 7. g1 If there are multiple, then multiple R g1 They may be the same or different, and there may be multiple R g1 R may represent a ring structure formed by combining with other elements. g2 is and R g3 Each of these independently represents a substituted or unsubstituted linear or branched alkyl group, alkoxy group or alkoxycarbonyloxy group having 1 to 12 carbon atoms, a substituted or unsubstituted monocyclic or polycyclic cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, hydroxyl group, halogen atom having 6 to 12 carbon atoms, or a ring structure formed by combining these groups. k11 and k12 are each independently integers from 0 to 4. R g2 is and R g3 If each of them is multiple, then multiple R g2 is and R g3 These may be the same or different.

[0161] In the above equation (X-5), R d1 and R d2 Each of these independently represents a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, an alkoxy group or alkoxycarbonyl group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, a halogen atom, a halogenated alkyl group having 1 to 4 carbon atoms, a nitro group, or a ring structure formed by two or more of these groups being combined. k6 and k7 are each independently integers from 0 to 5. d1 and R d2 If each of them is multiple, then multiple R d1 and R d2 These may be the same or different.

[0162] In the above equation (X-6), R e1 and R e2Each is independently a halogen atom, a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k8 and k9 are each independently an integer of 0 to 4.

[0163] Examples of the substituent that may substitute the hydrogen atom of each of the above groups include halogen atoms such as fluorine atom, chlorine atom, bromine atom, iodine atom, hydroxy group, carboxy group, cyano group, nitro group, alkyl group (when substituting the hydrogen atom of a cycloalkyl group or an aromatic hydrocarbon group), aryl group (when substituting the hydrogen atom of an alkyl group), alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, acyloxy group, etc. Among these, hydroxy group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, acyloxy group are preferable, and alkoxy group or alkoxycarbonyl group is more preferable.

[0164] Examples of the photo-dissociable base include compounds represented by the following formulae.

[0165] [Chemical formula]

[0166] Among these, sulfonium salts are preferable as the photo-dissociable base, triarylsulfonium salts are more preferable, and triphenylsulfonium salicylate and triphenylsulfonium 10-camphorsulfonate are even more preferable.

[0167] The lower limit of the content of the acid diffusion controller is preferably 3 parts by mass, more preferably 4 parts by mass, and even more preferably 5 parts by mass with respect to 100 parts by mass in total of the radiation-sensitive acid generator. The upper limit of the above content is preferably 150 parts by mass, more preferably 120 parts by mass, and even more preferably 110 parts by mass.

[0168] By setting the content of the acid diffusion control agent within the above range, the lithography performance of the radiation-sensitive resin composition can be further improved. The radiation-sensitive resin composition may contain one or more acid diffusion control agents.

[0169] (solvent) The radiation-sensitive resin composition according to this embodiment contains a solvent. The solvent is not particularly limited as long as it is capable of dissolving or dispersing at least the resin A, the resin B, and the radiation-sensitive acid generator, etc.

[0170] Examples of solvents include alcohol-based solvents, ether-based solvents, ketone-based solvents, amide-based solvents, ester-based solvents, and hydrocarbon-based solvents.

[0171] Examples of alcohol-based solvents include, Monoalcohol solvents with 1 to 18 carbon atoms, such as iso-propanol, 4-methyl-2-pentanol, 3-methoxybutanol, n-hexanol, 2-ethylhexanol, furfuryl alcohol, cyclohexanol, 3,3,5-trimethylcyclohexanol, and diacetone alcohol; Polyhydric alcohol solvents with 2 to 18 carbon atoms, such as ethylene glycol, 1,2-propylene glycol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, and tripropylene glycol; Examples include polyhydric alcohol partial ether solvents, in which some of the hydroxyl groups of the above-mentioned polyhydric alcohol solvents have been etherified.

[0172] Examples of ether-based solvents include, Dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether; Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran; Aromatic ring-containing ether solvents such as diphenyl ether and anisole (methylphenyl ether); Examples include polyhydric alcohol ether solvents, which are obtained by etherifying the hydroxyl groups of the above-mentioned polyhydric alcohol solvents.

[0173] Examples of ketone solvents include chain-like ketone solvents such as acetone, butanone, and methyl-iso-butyl ketone: Cyclopentanone, cyclohexanone, methylcyclohexanone, and other cyclic ketone solvents: Examples include 2,4-pentanedione, acetonylacetone, and acetophenone.

[0174] Examples of amide solvents include cyclic amide solvents such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone; Examples of chain-like amide solvents include N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, and N-methylpropionamide.

[0175] Examples of ester-based solvents include, Monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate; Polyhydric alcohol partial ether acetate solvents such as diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, and dipropylene glycol monomethyl ether acetate; Lactone-based solvents such as γ-butyrolactone and valerolactone; Carbonate-based solvents such as diethyl carbonate, ethylene carbonate, and propylene carbonate; Examples of polycarboxylic acid diester solvents include propylene glycol diacetate, methoxytriglycol acetate, diethyl oxalate, ethyl acetoacetate, ethyl lactate, and diethyl phthalate.

[0176] Examples of hydrocarbon solvents include, for example, Aliphatic hydrocarbon solvents such as n-hexane, cyclohexane, and methylcyclohexane; Examples include aromatic hydrocarbon solvents such as benzene, toluene, di-iso-propylbencene, and n-amylnaphthalene.

[0177] Among these, ester solvents and ketone solvents are preferred, polyhydric alcohol partial ether acetate solvents, cyclic ketone solvents, and lactone solvents are more preferred, and propylene glycol monomethyl ether acetate, cyclohexanone, and γ-butyrolactone are even more preferred. The radiation-sensitive resin composition may contain one or more solvents.

[0178] (Other optional components) The above-mentioned radiation-sensitive resin composition may contain other optional components in addition to the components listed above. Examples of these other optional components include crosslinking agents, segregation promoters, surfactants, alicyclic skeleton-containing compounds, sensitizers, and the like. These other optional components may be used individually or in combination of two or more types.

[0179] (Crosslinking agent) The crosslinking agent is a compound having two or more functional groups. In the baking process after the batch exposure process, it causes a crosslinking reaction in the resin component via an acid-catalyzed reaction, increasing the molecular weight of the resin component and thereby reducing the solubility of the pattern exposure area in the developer. Examples of the functional groups include (meth)acryloyl groups, hydroxymethyl groups, alkoxymethyl groups, epoxy groups, vinyl ether groups, and the like.

[0180] (Area of ​​localization promoter) The phase separation promoter has the effect of more efficiently causing the high-fluorine content resin to be unevenly distributed on the resist film surface. By including this phase separation promoter in the radiation-sensitive resin composition, the addition amount of the high-fluorine content resin can be made less than before. Therefore, while maintaining the lithography performance of the radiation-sensitive resin composition, elution of components from the resist film into the immersion medium can be further suppressed, or immersion exposure can be performed at a higher speed by high-speed scanning, and as a result, the hydrophobicity of the resist film surface that suppresses immersion-derived defects such as watermark defects can be improved. Examples of those that can be used as such a phase separation promoter include low molecular weight compounds having a relative dielectric constant of 30 or more and 200 or less and a boiling point of 100°C or more at 1 atm. Specific examples of such compounds include lactone compounds, carbonate compounds, nitrile compounds, polyhydric alcohols, and the like.

[0181] Examples of the lactone compound include γ-butyrolactone, valerolactone, mevalonic lactone, norbornane lactone, and the like.

[0182] Examples of the carbonate compound include propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate, and the like.

[0183] Examples of the nitrile compound include succinonitrile and the like.

[0184] Examples of the polyhydric alcohol include glycerin and the like.

[0185] The amount of the segregation accelerator is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, and even more preferably 25 parts by mass or more, based on 100 parts by mass of the total amount of resin in the radiation-sensitive resin composition. Furthermore, it is preferably 300 parts by mass or less, more preferably 200 parts by mass or less, even more preferably 100 parts by mass or less, and particularly preferably 80 parts by mass or less. The radiation-sensitive resin composition may contain one or more types of segregation accelerators.

[0186] (Surfactants) Surfactants improve the properties of coating, striation, and development. Examples of surfactants include nonionic surfactants such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, and polyethylene glycol distearate; commercially available examples include KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, and No. 75. Examples include 95 (manufactured by Kyoeisha Chemical), F-Top EF301, EF303, EF352 (manufactured by Tochem Products), Megafac F171, F173 (manufactured by DIC), Florard FC430, FC431 (manufactured by Sumitomo 3M), Asahiguard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (manufactured by Asahi Glass Industries), etc. The surfactant content in the above radiation-sensitive resin composition is usually 2 parts by mass or less per 100 parts by mass of resin.

[0187] (Alicyclic skeleton-containing compounds) Compounds containing alicyclic skeletons have the effect of improving dry etching resistance, pattern shape, and adhesion to the substrate.

[0188] Examples of alicyclic skeleton-containing compounds include, Adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and t-butyl 1-adamantanecarboxylic acid; Deoxycholic acid esters such as t-butyl deoxycholate, t-butoxycarbonylmethyl deoxycholate, and 2-ethoxyethyl deoxycholate; Lithocholic acid esters such as t-butyl lithocholate, t-butoxycarbonylmethyl lithocholate, and 2-ethoxyethyl lithocholate; Examples include 3-[2-hydroxy-2,2-bis(trifluoromethyl)ethyl]tetracyclo[4.4.0.1(2,5).1(7,10)]dodecane and 2-hydroxy-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo[4.2.1.0(3,7)]nonane. The content of the alicyclic skeleton-containing compound in the above radiation-sensitive resin composition is usually 5 parts by mass or less per 100 parts by mass of resin.

[0189] (Sensitizer) The sensitizer increases the amount of acid produced from the radiation-sensitive acid generator, etc., and thus improves the "apparent sensitivity" of the above-mentioned radiation-sensitive resin composition.

[0190] Examples of sensitizers include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, and phenothiazines. These sensitizers may be used alone or in combination of two or more. The content of the sensitizer in the above-mentioned radiation-sensitive resin composition is usually 2 parts by mass or less per 100 parts by mass of resin.

[0191] <Method for preparing a radiation-sensitive resin composition> The above radiation-sensitive resin composition can be prepared, for example, by mixing resin A, resin B, the above radiation-sensitive acid generator, a high-fluorine-content resin if necessary, and a solvent in predetermined proportions. After mixing, the above radiation-sensitive resin composition is preferably filtered using, for example, a filter with a pore size of about 0.05 μm. The solid content concentration of the above radiation-sensitive resin composition is usually 0.1% to 50% by mass, preferably 0.5% to 30% by mass, and more preferably 1% to 20% by mass.

[0192] <Method for forming a resist pattern> A method for forming a resist pattern according to one embodiment of the present invention is: The above radiation-sensitive resin composition is applied directly or indirectly to a substrate to form a resist film (hereinafter also referred to as the "resist film formation step"), The process of exposing the above-mentioned resist film by immersion lithography (hereinafter also referred to as the "exposure process"), and This process includes developing the exposed resist film (hereinafter also referred to as the "development process").

[0193] According to the above method for forming a resist pattern, since the above-mentioned radiation-sensitive resin composition containing resin A is used, it is possible to form a resist pattern with good sensitivity, high water repellency, and few defects. The following describes each step.

[0194] [Resist film formation process] In this step (resist film formation step), a resist film is formed using the above-mentioned radiation-sensitive resin composition. Examples of substrates for forming this resist film include conventionally known materials such as silicon wafers, silicon dioxide wafers, and aluminum-coated wafers. Alternatively, an organic or inorganic anti-reflective film, such as those disclosed in Japanese Patent Publication No. 6-12452 or Japanese Patent Publication No. 59-93448, may be formed on the substrate. Examples of coating methods include rotary coating (spin coating), casting coating, and roll coating. After coating, pre-baking (PB) may be performed as needed to volatilize the solvent in the coating film. The PB temperature is usually 60°C to 140°C, with 80°C to 120°C being preferred. The PB time is usually 5 seconds to 600 seconds, with 10 seconds to 300 seconds being preferred. The thickness of the formed resist film is preferably 10 nm to 1,000 nm, and more preferably 10 nm to 500 nm.

[0195] When performing immersion exposure, regardless of the presence or absence of water-repellent polymer additives such as the high-fluorine-content resin in the above-mentioned radiation-sensitive resin composition, a protective immersion film insoluble in the immersion liquid may be provided on the formed resist film to avoid direct contact between the immersion liquid and the resist film. As the protective immersion film, a film formed with the above-mentioned water-repellency improving agent may be used. As the protective immersion film, either a solvent-peelable protective film that is peeled off with a solvent before the development process (see, for example, Japanese Patent Application Publication No. 2006-227632) or a developer-peelable protective film that is peeled off simultaneously with development in the development process (see, for example, Japanese Patent Application Publication Nos. WO2005-069076 and WO2006-035790) may be used. However, from the viewpoint of throughput, it is preferable to use a developer-peelable protective immersion film.

[0196] Furthermore, when the subsequent exposure process is carried out with radiation of a wavelength of 50 nm or less, it is preferable to use a resin having the above structural units (I) and (IV) as the base resin in the above composition.

[0197] [Synthesis process] In this step (the exposure step described above), the resist film formed in the resist film formation step described above is exposed by irradiating it with radiation through a photomask (and, in some cases, through an immersion medium such as water). The radiation used for exposure can be electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, EUV (extreme ultraviolet light), X-rays, and gamma rays, depending on the line width of the desired pattern; or charged particle beams such as electron beams and alpha rays. Among these, far ultraviolet light, electron beams, and EUV are preferred, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), electron beams, and EUV are more preferred, and electron beams and EUV with wavelengths of 50 nm or less, which are positioned as next-generation exposure technologies, are even more preferred.

[0198] When exposure is performed by immersion lithography, the immersion liquid used can be, for example, water or a fluorinated inert liquid. The immersion liquid is preferably transparent to the exposure wavelength and has the smallest possible temperature coefficient of refractive index to minimize distortion of the optical image projected onto the film. In particular, when the exposure light source is ArF excimer laser light (wavelength 193 nm), in addition to the above considerations, water is preferred due to its availability and ease of handling. When water is used, a small amount of an additive that reduces the surface tension of the water and increases its surfactant properties may be added. This additive is preferably one that does not dissolve the resist film on the wafer and has negligible effect on the optical coating on the underside of the lens. Distilled water is preferred as the water used.

[0199] After the exposure described above, it is preferable to perform a post-exposure bake (PEB) to promote the dissociation of acid-dissociable groups in the resin, etc., by the acid generated from the radiation-sensitive acid generator during exposure in the exposed portion of the resist film. This PEB creates a difference in solubility in the developer between the exposed and unexposed portions. The PEB temperature is usually 50°C to 180°C, with 80°C to 130°C being preferred. The PEB time is usually 5 seconds to 600 seconds, with 10 seconds to 300 seconds being preferred.

[0200] [Development process] In this process (the development process described above), the resist film exposed in the exposure process is developed. This allows for the formation of a predetermined resist pattern. After development, it is common to wash the film with a rinsing solution such as water or alcohol and then dry it.

[0201] Examples of developers used in the above development process include, in the case of alkaline development, an alkaline aqueous solution containing at least one alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, or 1,5-diazabicyclo-[4.3.0]-5-nonene. Among these, an aqueous TMAH solution is preferred, and a 2.38% by mass aqueous TMAH solution is more preferred.

[0202] Furthermore, in the case of organic solvent development, examples of organic solvents include hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, alcohol solvents, or solvents containing organic solvents. Examples of the above organic solvents include one or more of the solvents listed above as solvents for the radiation-sensitive resin composition. Among these, ether solvents, ester solvents, and ketone solvents are preferred. As for ether solvents, glycol ether solvents are preferred, and ethylene glycol monomethyl ether and propylene glycol monomethyl ether are more preferred. As for ester solvents, acetate ester solvents are preferred, and n-butyl acetate and amyl acetate are more preferred. As for ketone solvents, chain ketones are preferred, and 2-heptanone is more preferred. The content of organic solvents in the developer is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 99% by mass or more. Examples of components other than organic solvents in the developer include water and silicone oil.

[0203] As mentioned above, either an alkaline developer or an organic solvent developer may be used as the developing solution.

[0204] Examples of development methods include immersing the substrate in a tank filled with developer solution for a certain period of time (dip method), developing by piling the developer solution onto the substrate surface using surface tension and letting it remain still for a certain period of time (paddle method), spraying the developer solution onto the substrate surface (spray method), and continuously applying the developer solution to a substrate rotating at a constant speed while scanning the developer solution dispensing nozzle at a constant speed (dynamic dispensing method).

[0205] <Water-repellent agent> A water-repellent improving agent according to one embodiment of the present invention includes the above-mentioned resin A. The water-repellent improving agent may also contain other optional components as long as they do not impair the effects of the present invention. By including a predetermined resin A, the water-repellent improving agent can easily impart, improve, or enhance the water repellency of a resist film or the like.

[0206] Resin A is a resin having a first structural unit that includes a substructure represented by the above formula (1). Resin A can be any of the resins described in the section on radiation-sensitive resin compositions.

[0207] Examples of optional components include solvents. The solvent can be any of those described in the section on radiation-sensitive resin compositions.

[0208] When performing immersion exposure using, for example, ArF excimer laser light, with a radiation-sensitive resin composition containing the water-repellency improving agent of the present invention, it is possible to prevent or reduce the elution of the composition into the immersion liquid, and to prevent or reduce contamination of the lens of the exposure light source.

[0209] Furthermore, when using a radiation-sensitive resin composition containing the water-repellency improving agent of the present invention, for example, when exposure is performed using EUV (extreme ultraviolet) light, it becomes possible to suppress or reduce droplet residue defects during rinsing with fresh water after development.

[0210] Alternatively, a liquid immersion upper film may be formed on a resist film using a liquid immersion upper film forming composition containing the water-repellent improving agent and solvent of the present invention. [Examples]

[0211] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. The methods for measuring various physical properties are shown below. In the following synthesis examples, unless otherwise specified, parts by mass means the value when the total mass of the monomers used is 100 parts by mass, and mol% means the value when the total number of moles of the monomers used is 100 mol%.

[0212] [Weight-average molecular weight (Mw) and number-average molecular weight (Mn)] The Mw and Mn of the prepared polymers were measured by gel permeation chromatography (GPC) using GPC columns manufactured by Tosoh Corporation (two "G2000HXL" columns, one "G3000HXL" column, and one "G4000HXL" column) under the following conditions. The degree of dispersion (Mw / Mn) was calculated from the measured results of Mw and Mn. Elution solvent: tetrahydrofuran Flow rate: 1.0mL / min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Column temperature: 40℃ Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0213] [ 13 C-NMR analysis] polymer 13 ¹¹C-NMR analysis was performed using a nuclear magnetic resonance spectrometer (JNM-Delta400, manufactured by JEOL Ltd.).

[0214] <[F] Synthesis of compound (monomer)> The monomers used in the synthesis of the [E] polymer in each example and examples of their synthesis methods are shown below.

[0215] [Synthesis Example 1] (Synthesis of compound (F-1)) In a reaction vessel, 20.0 mmol of acetone, 30.0 mmol of (trifluoromethyl)trimethylsilane, 0.20 mmol of tetrabutylammonium fluoride, and 50 g of tetrahydrofuran were added and the mixture was stirred at room temperature for 1 hour. After dilution with water, the mixture was extracted with ethyl acetate, and the organic layer was separated. The resulting organic layer was washed with saturated sodium chloride aqueous solution, and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the fluorinated alcohol was purified by atmospheric distillation to obtain the fluorinated alcohol in good yield.

[0216] To the above fluorinated alcohol compound, 20.0 mmol of bromoacetyl bromide, 30.0 mmol of triethylamine, and 50 g of tetrahydrofuran were added and the mixture was stirred at room temperature for 2 hours. After dilution with water, the mixture was extracted with ethyl acetate, and the organic layer was separated. The obtained organic layer was washed with saturated ammonium chloride aqueous solution, and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the bromo compound was obtained in good yield by column chromatography.

[0217] To the above bromo compound, 30.0 mmol of potassium carbonate, 30.0 mmol of methacrylic acid, and 50 g of dimethylformamide were added and the mixture was stirred at 50°C for 4 hours. The reaction solution was then cooled to below 30°C, diluted with water, and extracted with ethyl acetate to separate the organic layer. The obtained organic layer was washed with saturated sodium chloride aqueous solution and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the compound represented by the following formula (F-1) (hereinafter sometimes referred to as "compound (F-1)" or "monomer (F-1)") was obtained in good yield. The synthesis scheme of compound (F-1) is shown below.

[0218] [ka]

[0219] [Synthesis Examples 2-5] (Synthesis of monomer (F-2) to monomer (F-5)) Compounds represented by the following formulas (F-2) to (F-5) were synthesized in the same manner as in Synthesis Example 1, except that the raw materials and precursors were changed as appropriate (hereinafter, the compounds represented by formulas (F-2) to (F-5) may be referred to as "compound (F-2)" to "compound (F-5)" or "monomer (F-2)" to "monomer (F-5)" respectively).

[0220] [ka]

[0221] [Synthesis Example 6] (Synthesis of compound (F-6)) To the bromo compound obtained in Synthesis Example 1 above, 25.0 mmol of zinc powder, 2.00 mmol of chlorotrimethylsilane, and 50 g of tetrahydrofuran were added and the mixture was stirred at room temperature for 1 hour. Then, 20.0 mmol of acetone was added to the reaction solution and the mixture was stirred at room temperature for a further 6 hours. After that, saturated aqueous ammonium chloride solution was added to the reaction solution to terminate the reaction, and then ethyl acetate was added for extraction, separating the organic layer. The obtained organic layer was washed with saturated aqueous sodium chloride solution and then with water. After drying with sodium sulfate, the solvent was removed by distillation, and the alcohol compound was obtained in good yield by column chromatography.

[0222] To the above alcohol mixture, 30.0 mmol of triethylamine, 30.0 mmol of methacrylate chloride, and 50 g of tetrahydrofuran were added and the mixture was stirred at 80°C for 1 hour. The reaction solution was then cooled to below 30°C, saturated ammonium chloride aqueous solution was added to terminate the reaction, and ethyl acetate was added for extraction, separating the organic layer. The obtained organic layer was washed with saturated sodium chloride aqueous solution, and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the mixture was purified by column chromatography to obtain the compound represented by the following formula (F-6) (hereinafter sometimes referred to as "compound (F-6)" or "monomer (F-6)") in good yield. The synthesis scheme of compound (F-6) is shown below.

[0223] [ka]

[0224] [Synthesis Examples 7-16] (Synthesis of monomer (F-7) to monomer (F-16)) Compounds represented by the following formulas (F-7) to (F-16) were synthesized in the same manner as in Synthesis Example 6, except that the raw materials and precursors were changed as appropriate (hereinafter, the compounds represented by formulas (F-7) to (F-16) may be referred to as "compound (F-7)" to "compound (F-16)" or "monomer (F-7)" to "monomer (F-16)" respectively).

[0225] [ka]

[0226] <Synthesis of polymers [A] and [E]> The monomers used in the synthesis of each polymer in each example and comparative example are shown below.

[0227] [ka]

[0228] [Synthesis Example 17] (Synthesis of Polymer (A-1)) Monomers (M-1), (M-2), and (M-13) were dissolved in 200 parts by mass of 2-butanone in a molar ratio of 40 / 15 / 45 (mol%), and AIBN (azobisisobutyronitrile) (3 mol% of the total monomers used, based on 100 mol%) was added as an initiator to prepare the monomer solution. 100 parts by mass of 2-butanone was placed in the reaction vessel, and after purging with nitrogen for 30 minutes, the reaction vessel was heated to 80°C, and the monomer solution was added dropwise over 3 hours while stirring. The start of the dropwise addition was defined as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours.

[0229] After the polymerization reaction was complete, the polymerization solution was cooled to below 30°C by water cooling. The cooled polymerization solution was added to methanol (2,000 parts by mass), and the precipitated white powder was filtered off. The filtered white powder was washed twice with methanol, filtered again, and dried at 50°C for 10 hours to obtain a white powdery polymer (A-1) (yield: 82%). The Mw of polymer (A-1) was 8,800, and the Mw / Mn ratio was 1.50. 13 13C-NMR analysis revealed that the content of each structural unit derived from (M-1), (M-2), and (M-13) was 41.3 mol%, 13.8 mol%, and 44.9 mol%, respectively.

[0230] [Synthesis Examples 18-27] (Synthesis of polymers (A-2) to (A-11)) Polymers (A-2) to (A-11) were synthesized in the same manner as in Synthesis Example 17, except that monomers of the types and proportions shown in Table 1 below were used. The content (mol%), yield (%), and physical properties (Mw and Mw / Mn) of each structural unit of the obtained polymers are shown in accordance with Table 1 below. In Table 1 below, "-" indicates that the corresponding monomer was not used.

[0231] [Table 1]

[0232] [Synthesis Example 28] (Synthesis of polymer (A-12)) Monomer (M-1) and monomer (M-18) were dissolved in 1-methoxy-2-propanol (200 parts by mass) to a molar ratio of 50 / 50 (mol%), and AIBN (5 mol%) was added as an initiator to prepare a monomer solution. 100 parts by mass of 1-methoxy-2-propanol was placed in a reaction vessel, and after purging with nitrogen for 30 minutes, the reaction vessel was heated to 80°C, and the monomer solution was added dropwise over 3 hours while stirring. The start of the dropwise addition was defined as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours.

[0233] After the polymerization reaction was complete, the polymerization solution was cooled to below 30°C by water cooling. The cooled polymerization solution was added to hexane (2,000 parts by mass), and the precipitated white powder was filtered off. The filtered white powder was washed twice with hexane, filtered again, and dissolved in 1-methoxy-2-propanol (300 parts by mass). Then, methanol (500 parts by mass), triethylamine (50 parts by mass), and ultrapure water (10 parts by mass) were added, and the hydrolysis reaction was carried out at 70°C for 6 hours with stirring. After the reaction was complete, the residual solvent was removed by distillation, and the obtained solid was dissolved in acetone (100 parts by mass) and added dropwise to water (500 parts by mass) to solidify the resin. The obtained solid was filtered off and dried at 50°C for 13 hours to obtain a white powdery polymer (A-12) (yield: 80%). The Mw of polymer (A-12) was 5,200, and the Mw / Mn ratio was 1.60. 13 1C-NMR analysis revealed that the content of each structural unit derived from (M-1) and (M-18) was 51.3 mol% and 48.7 mol%, respectively.

[0234] [Synthesis Examples 29-31] (Synthesis of polymers (A-13) to (A-15)) Polymers (A-13) to (A-15) were synthesized in the same manner as in Synthesis Example 28, except that monomers of the types and proportions shown in Table 2 below were used. The content (mol%), yield (%), and physical properties (Mw and Mw / Mn) of each structural unit of the obtained polymers are shown in accordance with Table 2 below.

[0235] [Table 2]

[0236] [Synthesis Example 32] (Synthesis of Polymer (E-1)) Monomer (F-1) and monomer (M-2) were dissolved in 200 parts by mass of 2-butanone to a molar ratio of 80 / 20 (mol%), and AIBN (5 mol%) was added as an initiator to prepare a monomer solution. 100 parts by mass of 2-butanone was placed in a reaction vessel, and after purging with nitrogen for 30 minutes, the temperature inside the reaction vessel was raised to 80°C, and the monomer solution was added dropwise over 3 hours while stirring. The start of the dropwise addition was defined as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours.

[0237] After the polymerization reaction was complete, the polymerization solution was cooled to below 30°C by water cooling. The solvent was replaced with acetonitrile (400 parts by mass), then hexane (100 parts by mass) was added and stirred, and the acetonitrile layer was recovered. This process was repeated three times. By replacing the solvent with propylene glycol monomethyl ether acetate, a solution of polymer (E-1) was obtained (yield: 70%). The Mw of polymer (E-1) was 5,100, and the Mw / Mn ratio was 1.55. Furthermore, 13 ¹³C-NMR analysis revealed that the content of each structural unit derived from (F-1) and (M-2) was 80.3 mol% and 19.7 mol%, respectively.

[0238] [Synthesis Examples 33-53] (Synthesis of polymer (E-2) to polymer (E-22)) Polymers (E-2) to (E-22) were synthesized in the same manner as in Synthesis Example 32, except that monomers of the types and proportions shown in Table 3 below were used. The content (mol%), yield (%), and physical properties (Mw and Mw / Mn) of each structural unit of the obtained polymers are shown in accordance with Table 3 below.

[0239] [Table 3]

[0240] [Comparative Synthesis Examples 54-70] (Synthesis of polymers (E-23) to (E-39)) Polymers (E-23) to (E-39) were synthesized in the same manner as in Synthesis Example 32, except that monomers of the types and proportions shown in Table 4 below were used. The content (mol%), yield (%), and physical properties (Mw and Mw / Mn) of each structural unit of the obtained polymers are shown in accordance with Table 4 below.

[0241] [Table 4]

[0242] <Preparation of radiation-sensitive resin composition> The components other than polymers [A] and [E] used in the preparation of each radiation-sensitive resin composition are shown below.

[0243] [[B] Acid Generator] B-1 to B-5: Compounds represented by the following formulas (B-1) to (B-5)

[0244] [ka]

[0245] [[C] Acid diffusion inhibitor] C-1 to C-5: Compounds represented by the following formulas (C-1) to (C-5).

[0246] [ka]

[0247] [[D] Solvent] D-1: Propylene glycol monomethyl ether acetate D-2: Propylene glycol monomethyl ether D-3: γ-Butyrolactone D-4: Ethyl lactate

[0248] [Preparation of positive-type radiation-sensitive resin composition for ArF exposure] [Example 1] 100 parts by mass of (A-1) as a polymer, 14.0 parts by mass of (B-1) as an acid generator, 5.0 parts by mass of (C-1) as an acid diffusion controller, 3.0 parts by mass (solid content) of (E-1) as a polymer, and 3,230 parts by mass of a mixed solvent of (D-1) / (D-2) / (D-3) = 70 / 29 / 1 (mass ratio) were mixed and filtered through a membrane filter with a pore size of 0.2 μm to prepare a radiation-sensitive resin composition (J-1).

[0249] [Examples 2 to 48 and Comparative Examples 1 to 17] Except for using the components of the types and contents shown in Table 5 below, radiation-sensitive resin compositions (J-2) to (J-48) and (CJ-1) to (CJ-17) were prepared in the same manner as in Example 1.

[0250] [Table 5]

[0251] [Formation of a resist pattern using an ArF exposure positive-type radiation-sensitive resin composition] On a 12-inch silicon wafer, a base layer anti-reflective coating composition (ARC66, manufactured by Brewer Science) was applied using a spin coater (CLEAN TRACK ACT12, manufactured by Tokyo Electron Limited), and then heated at 205°C for 60 seconds to form a base layer anti-reflective coating with an average thickness of 100 nm. On this base layer anti-reflective coating, the ArF exposure positive-type radiation-sensitive resin composition prepared above was applied using the same spin coater, and pre-bake (PB) was performed at 100°C for 60 seconds. Subsequently, a resist film with an average thickness of 90 nm was formed by cooling at 23°C for 30 seconds. Next, this resist film was exposed using an ArF excimer laser immersion lithography system (TWINSCAN XT-1900i, manufactured by ASML) under optical conditions of NA=1.35 and Dipole (σ=0.9 / 0.7) through a 40 nm line-and-space mask pattern. After exposure, post-exposure baking (PEB) was performed at 100°C for 60 seconds. Subsequently, the resist film was alkaline developed using a 2.38% by mass aqueous TMAH solution as the alkaline developer. After development, it was washed with water and then dried to form a positive-type resist pattern (40 nm line and space pattern).

[0252] <Rating> The sensitivity and number of defects after development of resist patterns formed using the above-described radiation-sensitive resin composition for ArF exposure were evaluated according to the method described below. Furthermore, the receding contact angle of the resist film before ArF exposure was evaluated according to the method described below. The results are shown in Table 6 below. A scanning electron microscope (Hitachi High-Technologies Corporation's "CG-5000") was used to measure the length of the resist patterns.

[0253] [sensitivity] In forming a resist pattern using the above-mentioned radiation-sensitive resin composition for ArF exposure, the exposure amount used to form a 40 nm line-and-space pattern is defined as the optimal exposure amount, and this optimal exposure amount is set to the sensitivity (mJ / cm²). 2 The sensitivity was set to 25 mJ / cm². 2 The following cases are considered "good" and 25 mJ / cm². 2If it exceeded this value, it was rated as "poor."

[0254] [Backward contact angle after PB] For the resist film before ArF exposure in the resist pattern formation method described above, the receding contact angle was measured using a KRUS DSA-10 under the following procedure in an environment of room temperature (23°C), relative humidity (40%), and atmospheric pressure.

[0255] Water was discharged from the DSA-10 needle to form a 25 μL droplet on the resist film. The droplet was then aspirated at a rate of 10 μL / min for 90 seconds using the needle, while the contact angle was measured every second (90 times in total). In this measurement, the average value of the contact angles at a total of 20 points from the point where the contact angle stabilized was calculated and defined as the post-PB recession contact angle (°). A post-PB recession contact angle of 70° or higher was evaluated as "good," and a value below 70° was evaluated as "poor."

[0256] [Number of development defects] A resist film was exposed at the optimal exposure level to form a line-and-space pattern with a line width of 40 nm, and this was used as a wafer for defect inspection. The number of defects on this wafer was measured using a defect inspection device (KLA-Tencor's "KLA2810"). The measured defects were then classified into those determined to be originating from the resist film and those determined to be originating from external substances, and the number of defects determined to be originating from the resist film was calculated. After development, the number of defects determined to be originating from the resist film was evaluated as "good" if it was 15 or less, and as "bad" if it was more than 15.

[0257] [Table 6]

[0258] As is clear from the results in Table 6, the radiation-sensitive resin composition of the example had good sensitivity, receding contact angle performance after PB, and defect performance after development when used for ArF exposure. In contrast, in the comparative examples, each characteristic was inferior to that of the example. Therefore, when the radiation-sensitive resin composition of the example is used for ArF exposure, a resist pattern with high sensitivity, high water repellency, and few defects can be formed.

[0259] [Preparation of Radiation-Sensitive Resin Composition for Extreme Ultraviolet (EUV) Exposure] [Example 49] [A] 100 parts by mass of (A-12) as a polymer, [B] 15.0 parts by mass of (B-1) as an acid generator, [C] 10.0 parts by mass of (C-2) as an acid diffusion controller, [E] 4.0 parts by mass of (E-1) as a polymer, and 6,110 parts by mass of a mixed solvent of (D-1) / (D-4)=70 / 30 (mass ratio) as [D] were mixed and filtered through a membrane filter with a pore size of 0.2 μm to prepare a radiation-sensitive resin composition (J-49).

[0260] [Examples 50 to 72 and Comparative Examples 18 to 24] The radiation-sensitive resin compositions (J-50) to (J-72) and (CJ-18) to (CJ-24) were prepared in the same manner as in Example 49, except that the components of the types and contents shown in Table 7 below were used.

[0261]

Table 7

[0262] [Formation of Resist Pattern Using Radiation-Sensitive Resin Composition for EUV Exposure] On a 12-inch silicon wafer, a base layer anti-reflective coating composition (Brewer Science's "ARC66") was applied using a spin coater (CLEAN TRACK ACT12, manufactured by Tokyo Electron Limited), and then heated at 205°C for 60 seconds to form a base layer anti-reflective coating with an average thickness of 105 nm. The radiation-sensitive resin composition for EUV exposure prepared above was applied to this base layer anti-reflective coating using the same spin coater, and PB was performed at 130°C for 60 seconds. Subsequently, a resist film with an average thickness of 55 nm was formed by cooling at 23°C for 30 seconds. Next, this resist film was exposed using an EUV exposure apparatus (ASML's "NXE3300") with NA=0.33, illumination conditions: Conventional s=0.89, and mask: imecDEFECT32FFR02. After exposure, PEB was performed at 120°C for 60 seconds. Subsequently, the resist film was alkaline-developed using a 2.38% by mass aqueous TMAH solution as the alkaline developer. After development, it was washed with water and then dried to form a positive-type resist pattern (32 nm line and space pattern).

[0263] <Rating> The sensitivity and LWR performance of resist patterns formed using the above-described radiation-sensitive resin composition for EUV exposure were evaluated according to the method described below. The results are shown in Table 8. A scanning electron microscope ("CG-5000" manufactured by Hitachi High-Technologies Corporation) was used to measure the length of the resist patterns.

[0264] [sensitivity] In forming a resist pattern using the above-mentioned radiation-sensitive resin composition for EUV exposure, the exposure amount for forming a 32nm line-and-space pattern is defined as the optimal exposure amount, and this optimal exposure amount is set to the sensitivity (mJ / cm²). 2 The sensitivity was set to 25 mJ / cm². 2 The following cases are considered "good" and 25 mJ / cm². 2 If it exceeded this value, it was rated as "poor."

[0265] [Number of development defects] A resist film was exposed at the optimal exposure level to form a line-and-space pattern with a line width of 32 nm, and this was used as a wafer for defect inspection. The number of defects on this wafer was measured using a defect inspection device (KLA-Tencor's "KLA2810"). The measured defects were then classified into those determined to be from the resist film and those determined to be from external foreign matter, and the number of defects determined to be from the resist film was calculated. After development, the number of defects determined to be from the resist film was evaluated as "good" if it was 15 or less, and as "bad" if it was more than 15.

[0266] [Table 8]

[0267] As is clear from the results in Table 8, the radiation-sensitive resin composition of the example showed good sensitivity and post-development defect performance when used in EUV exposure. In contrast, the comparative example exhibited inferior characteristics compared to the example. Therefore, when the radiation-sensitive resin composition of the example is used in EUV exposure, it is possible to form a resist pattern with high sensitivity and few defects.

[0268] [Preparation of negative-type radiation-sensitive resin composition for ArF exposure, formation and evaluation of resist patterns using the composition] [Example 82] A radiation-sensitive resin composition (J-73) was prepared by mixing [A] 100 parts by mass of (A-1) as a polymer, [B] 10.0 parts by mass of (B-4) as an acid generator, [C] 5.0 parts by mass of (C-3) as an acid diffusion control agent, [E] 3.0 parts by mass of (E-1) as a polymer (solid content), and [D] 3,230 parts by mass of a mixed solvent with a mass ratio of (D-1) / (D-2) / (D-3) = 70 / 29 / 1 as a solvent, and filtering the mixture through a membrane filter with a pore size of 0.2 μm.

[0269] In forming a resist pattern using a positive-type radiation-sensitive resin composition for ArF exposure, a resist film was formed in the same manner as above, except that the negative-type radiation-sensitive resin composition (J-73) prepared above was used as the radiation-sensitive resin composition. The film was then exposed to ArF light and subjected to PEB. Subsequently, the resist film was developed using n-butyl acetate as the organic solvent developer and dried to form a negative-type resist pattern (40 nm line and space pattern).

[0270] The resist patterns and resist films before ArF exposure using the above-mentioned negative-type radiation-sensitive resin composition for ArF exposure were evaluated in the same manner as the evaluation of the resist patterns using the above-mentioned positive-type radiation-sensitive resin composition for ArF exposure. As a result, the radiation-sensitive resin composition of Example 73 showed good sensitivity, receding contact angle performance after PB, and defect performance after development, even when a negative-type resist pattern was formed by ArF exposure. [Industrial applicability]

[0271] The radiation-sensitive resin composition, the resist pattern formation method using the same, and the water-repellency improving agent of the present invention provide good sensitivity to exposure light and enable the formation of highly water-repellent and defect-free resist patterns. The polymer of the present invention can be suitably used as a polymer component of the radiation-sensitive resin composition. The compound of the present invention can be suitably used as a monomer of the polymer. Therefore, these can be suitably used in semiconductor device processing processes and the like, where further miniaturization is expected in the future.

Claims

1. Resin A having a first structural unit represented by the following formula (2), 【Chemistry 1】 (In formula (2), X is a divalent linking group. R １ and R ２ Each of these independently comprises a monovalent linear hydrocarbon group having 1 to 40 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, or R １ and R ２ These are combined with each other to form a ring structure (a) with 3 to 20 member atoms, along with the carbon atoms to which they are bonded. R ３ This is a fluorinated chain hydrocarbon group having 1 to 4 carbon atoms. R is a hydrogen atom, a fluorine atom, or a monovalent hydrocarbon group that is unsubstituted or substituted with a halogen atom or an alkoxy group. Resin B containing a structural unit having an acid-dissociable group, Radiation-sensitive acid generator, and solvent A radiation-sensitive resin composition containing [a specific substance].

2. The radiation-sensitive resin composition according to claim 1, wherein the first structural unit is a group represented by the following formula (2-1) in formula (2). 【Chemistry 2】 (In formula (2-1), Z １ and Z ２ is each independently a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group, a monovalent fluorinated hydrocarbon group, a group in which one or more carbon atoms in a monovalent hydrocarbon group or a monovalent fluorinated hydrocarbon group are replaced with a linking group represented by *-O-*, *-CO-*, *-COO-* or *-OCO-* (where * in the above linking group is a bond to a carbon atom), or, Z １ and Z ２ are combined with each other and form a ring structure having 3 to 20 ring members together with the carbon atoms to which they are bonded. L is a single bond or a divalent organic group. n is an integer between 1 and 5.

3. The radiation-sensitive resin composition according to claim 1, wherein the resin A further has a second structural unit represented by the following formula (3). 【Transformation 3】 (In formula (3), R ４ This is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ５ It is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ６ and R ７ Each of these independently comprises a monovalent linear hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R ６ and R ７ These are divalent alicyclic groups with 3 to 20 carbon atoms, formed by combining them with the carbon atoms to which they are bonded.

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

5. The radiation-sensitive resin composition according to claim 1, wherein the structural unit having an acid-dissociable group in the resin B is represented by the following formula (4). 【Chemistry 4】 (In formula (4), R ８ This is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ９ It is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R １０ and R １１ Each of these independently comprises a monovalent linear hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R １０ and R １１ These are divalent alicyclic groups with 3 to 20 carbon atoms, formed by combining them with the carbon atoms to which they are bonded.

6. A step of forming a resist film by directly or indirectly applying the radiation-sensitive resin composition according to any one of claims 1 to 5 onto a substrate, A step of exposing the resist film by immersion lithography, and A method for forming a resist pattern, comprising the step of developing the exposed resist film.

7. The method for forming a resist pattern according to claim 6, wherein the radiation used in the exposure step is ArF excimer laser light, extreme ultraviolet (EUV), X-rays, or electron beam (EB).

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