Radiation-sensitive composition, pattern forming method, and radiation-sensitive acid generator

Abstract

The purpose of the present invention is to provide: a radiation-sensitive composition which is capable of forming a resist film that can exhibit sensitivity, LWR, pattern rectangularity, CDU, pattern circularity, and development defect performance at a sufficient level; and a pattern forming method. Another purpose of the present invention is to provide a radiation-sensitive acid generator that can be applied to the radiation-sensitive composition. A radiation-sensitive composition containing a polymer (A) containing a structural unit (I) having an acid-dissociable group, a radiation-sensitive acid generator (B) represented by formula (1), and a solvent (E). (In formula (1), R1 is a hydrogen atom, a nitro group, a hydroxyl group, a cyano group, a carboxyl group, a thiol group, a halogen atom, or a monovalent organic group, when there are a plurality of R1, the plurality of R1 are the same or different, R2 is a monovalent organic group having 1-40 carbon atoms, m is an integer of 1-5, and M + is a monovalent onium cation).

Description

Technical Field

[0001] This invention relates to a radiosensitive linear composition, a pattern forming method, and a radiosensitive linear acid generator. Background Technology

[0002] Photolithography, which uses a resist composition, is used in the formation of fine circuits in semiconductor devices. A representative process involves, for example, generating an acid by exposing a resist composition film to a dielectric mask pattern and irradiating it with radiation. The acid is then used as a catalyst to create a difference in the solubility of the polymer in an alkaline or organic developer between the exposed and unexposed areas, thereby forming a resist pattern on the substrate.

[0003] In the aforementioned photolithography technology, short-wavelength radiation such as ArF excimer lasers, or liquid immersion lithography (LIB), which involves exposure in a liquid medium filling the space between the lens and the resist film of the exposure apparatus, is used to advance pattern miniaturization. As a next-generation technology, photolithography using even shorter wavelength radiation such as electron beams, X-rays, and extreme ultraviolet (EUV) is also under investigation.

[0004] Regarding photoacid generators, which are the main components of resist compositions, perfluoroalkyl sulfonic acids, which can impart strong acids, are mostly used to improve sensitivity or resolution. On the other hand, due to increased environmental awareness in recent years, photoacid generators with reduced fluorine atom content have been studied (see Japanese Patent Application Publication No. 2014-126767).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2014-126767 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] Even photoacid generators with reduced fluorine atom content are required to maintain or exceed the performance of previous photoresists in terms of sensitivity or line width roughness (LWR), which indicates deviation of line width or resist pattern, pattern rectangularity, critical dimension uniformity (CDU), pattern circularity, and development defect performance.

[0010] The object of this invention is to provide a radiosensitive linear composition capable of forming a resist film that adequately exhibits properties such as sensitivity, LWR, pattern rectangularity, CDU, pattern circularity, and development defect performance, as well as a method for pattern formation. Furthermore, the object of this invention is also to provide a radiosensitive linear acid generator applicable to the aforementioned radiosensitive linear composition.

[0011] Technical means to solve the problem

[0012] The inventors have made repeated efforts to solve this problem and have found that the objective can be achieved by adopting the following structure, thus completing this invention.

[0013] That is, in one embodiment of the present invention, therein relates to a radiosensitive linear composition comprising:

[0014] Polymer (A) containing structural units (I) with acid-dissociable groups.

[0015] The following formula (1) represents the radiosensitive linear acid generator (B), and

[0016] Solvent (E).

[0017] [Chemistry 1]

[0018]

[0019] (In the above formula (1),

[0020] R 1 It can be a hydrogen atom, nitro group, hydroxyl group, cyano group, carboxyl group, thiol group, halogen atom, or monovalent organic group; in R 1 In the case of multiple Rs, multiple Rs 1 They are the same or different;

[0021] R 2 It is a monovalent organic group with 1 to 40 carbon atoms;

[0022] m is an integer from 1 to 5;

[0023] M + (It is a monovalent onium cation)

[0024] The radiosensitive linear composition, by comprising the radiosensitive linear acid generator (B) represented by formula (1), can form a resist film that exhibits sufficient sensitivity, LWR, pattern rectangularity, CDU, pattern circularity, and development defect performance. For this reason, though not bound by any theory, it is speculated as follows.

[0025] The radiosensitive linear acid generator (B), by having a difluoromethyl group on the carbon atom adjacent to the sulfonate anion, maintains sufficient acidity and is highly polarized compared to existing radiosensitive linear acid generators with high fluorine atom content. It is speculated that, as a result, in the case of a positive resist, the high polarization of the radiosensitive linear acid generator (B) improves solubility in alkaline developers, thereby enhancing various properties such as LWR and development defect performance. Furthermore, it is speculated that, in the case of a negative resist, the high polarization of the radiosensitive linear acid generator (B) enhances the solubility restriction effect in developers, resulting in greater improvement in the shape of the exposed area. Moreover, by reducing the fluorine atom content, environmental impact can also be limited. It is speculated that the resist performance is achieved through these combined effects.

[0026] In another embodiment, the present invention relates to a pattern forming method, comprising:

[0027] The process of directly or indirectly coating the radiosensitive linear composition onto a substrate to form a resist film;

[0028] The process of exposing the resist film; and

[0029] The process of developing the exposed resist film.

[0030] In the pattern forming method, since the photosensitive linear composition is used, which is capable of forming a photoresist film with excellent sensitivity, LWR, pattern rectangularity, CDU, pattern circularity, and development defect performance, high-quality photoresist patterns can be formed efficiently.

[0031] In another embodiment of the present invention, therein is a radiosensitive linear acid generator, which is represented by the following formula (1).

[0032] [Chemistry 2]

[0033]

[0034] (In the above formula (1),

[0035] R 1 It can be a hydrogen atom, nitro group, hydroxyl group, cyano group, carboxyl group, thiol group, halogen atom, or monovalent organic group; in R 1 In the case of multiple Rs, multiple Rs 1 They are the same or different;

[0036] R 2 It is a monovalent organic group with 1 to 40 carbon atoms;

[0037] m is an integer from 1 to 5;

[0038] M + (It is a monovalent onium cation)

[0039] By preparing a radiosensitive linear composition containing the aforementioned radiosensitive linear acid generator, a resist film with excellent sensitivity, LWR, pattern rectangularity, CDU, pattern circularity, and development defect performance can be formed. Detailed Implementation

[0040] The embodiments of the present invention will now be described in detail, but the present invention is not limited to these embodiments. Furthermore, combinations of preferred embodiments are also preferred.

[0041] Radioactive linear compositions

[0042] The radiosensitive linear composition of this embodiment (hereinafter also simply referred to as the "composition") contains a polymer (A) comprising a structural unit (I) having an acid-dissociable group, a radiosensitive linear acid generator (B) represented by formula (1), and a solvent (E). The composition may also contain any other ingredients without compromising the effects of the present invention.

[0043] <Polymer (A)>

[0044] Polymer (A) is an aggregate of polymer chains containing structural units (hereinafter also referred to as "structural units (I)") having acid-dissociable groups (hereinafter also referred to as "basic polymer (A)"). An "acid-dissociable group" refers to a group that substitutes for hydrogen atoms in carboxyl groups, phenolic hydroxyl groups, alcoholic hydroxyl groups, sulfonyl groups, etc., and that dissociates under the action of an acid. The radiosensitive linear composition, through polymer (A) having structural units (I), exhibits excellent pattern-forming properties.

[0045] The base polymer (A) preferably includes, in addition to structural unit (I), structural unit (II) which contains at least one of the group consisting of lactone structure, cyclic carbonate structure, sulfonyl lactone structure and cyclic sulfone structure, as described later. It may also include other structural units besides structural unit (I) and structural unit (II). Each structural unit will be described below.

[0046] [Structural Unit (I)]

[0047] Structural unit (I) is a structural unit with an acid-dissociable group. An "acid-dissociable group" refers to a group that substitutes for the hydrogen atoms of carboxyl groups, phenolic hydroxyl groups, alcoholic hydroxyl groups, sulfonyl groups, etc., and dissociates under the action of an acid. Through exposure, the acid generated by the radiosensitive linear acid generator (B), described later, causes the acid-dissociable group in structural unit (I) to dissociate and generate carboxyl groups, etc. This creates a difference in the solubility of the resist film in the developer between the exposed and unexposed areas, enabling pattern formation.

[0048] As for the structural unit (I), there is no particular limitation as long as it contains an acid dissociative group. For example, structural units with a tertiary alkyl ester moiety, structural units with a tertiary alkyl substituted hydrogen atom of a phenolic hydroxyl group, structural units with an acetal bond, etc., are examples. From the viewpoint of improving the pattern-forming property of the radiosensitive linear composition, the structural unit represented by the following formula (2) is preferred (hereinafter also referred to as "structural unit (I-1)").

[0049] [Chemistry 3]

[0050]

[0051] (In the above formula (2),

[0052] R α It consists of hydrogen atoms, fluorine atoms, methyl groups, or trifluoromethyl groups;

[0053] R A1 It consists of hydrogen atoms or a monovalent hydrocarbon group having 1 to 20 carbon atoms;

[0054] R A2 and R A3 Each is independently a monovalent chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R A2 and R A3 A divalent alicyclic group with 3 to 20 carbon atoms that combine with each other and together with the carbon atoms they are bonded to form;

[0055] m11 and m12 are each independently 0 or 1; where m11 is 1 and m12 is 1.

[0056] When m11 is 0, L A1 Indicates a single bond or a divalent linker; when m11 is 1, L A1 (for bivalent linkage bases)

[0057] As L A1 Examples of divalent linkages include: alkyldiyl, cycloalkyldiyl, alkenyl, aryl, and groups containing -CO-, -CS-, -O-, -S-, -SO2-, -NR'-, or combinations thereof between the carbon-carbon bonds of these groups, or groups formed by combining these groups. R' is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. Some or all of the hydrogen atoms in these groups may be substituted, for example, by halogen atoms such as fluorine, chlorine, bromine, or iodine; hydroxyl; carboxyl; cyano; nitro; alkyl; alkoxy; alkoxycarbonyl; alkoxycarbonyloxy; acyl; acyloxy, or groups formed by substituting the hydrogen atoms of these groups with halogen atoms.

[0058] The preferred alkyl group is a alkyl group with 1 to 8 carbon atoms, such as methanediyl, ethanediyl, 1,3-propanediyl, or 2,2-propanediyl.

[0059] Examples of the cycloalkyl diesters include monocyclic cycloalkyl diesters such as cyclopentanediol and cyclohexanediol, and polycyclic cycloalkyl diesters such as norbornenediol and adamantanediol. Preferably, the cycloalkyl diester has 5 to 12 carbon atoms.

[0060] Examples of the alkenyl group include ethylenediyl, propylenediyl, and butenyldiyl. Preferably, the alkenyl group has 2 to 6 carbon atoms.

[0061] Examples of the aryl dimethyl group include phenyldimethyl, toluenedimethyl, and naphthyldimethyl. Preferably, the aryl dimethyl group has 6 to 15 carbon atoms.

[0062] As the R A1 The monovalent hydrocarbon groups represented by carbon 1 to 20 can be exemplified by: chain hydrocarbon groups with carbon 1 to 20, monovalent alicyclic hydrocarbon groups with carbon 3 to 20, and monovalent aromatic hydrocarbon groups with carbon 6 to 20.

[0063] As R A1 ~R A3 The monovalent chain hydrocarbon group representing 1 to 20 carbon atoms can be exemplified by, for example, monovalent straight-chain or branched saturated hydrocarbon groups with 1 to 20 carbon atoms, or monovalent straight-chain or branched unsaturated hydrocarbon groups with 2 to 20 carbon atoms. Examples of monovalent straight-chain or branched saturated hydrocarbon groups with 1 to 20 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-methylpropyl, 1-methylpropyl, tert-butyl, n-pentyl, isopentyl, and neopentyl. Examples of monovalent straight-chain or branched unsaturated hydrocarbon groups with 2 to 20 carbon atoms include alkenyl groups such as vinyl, propynyl, and butenyl; and alkynyl groups such as ethynyl, propynyl, and butynyl.

[0064] As the R A1 ~R A3The monovalent alicyclic hydrocarbon groups representing 3 to 20 carbon atoms can be categorized as monocyclic or polycyclic saturated hydrocarbon groups, or monocyclic or polycyclic unsaturated hydrocarbon groups. Examples of monocyclic saturated hydrocarbon groups include cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and other cycloalkyl groups. Examples of polycyclic saturated hydrocarbon groups include norbornyl, adamantyl, tricyclic decyl, tetracyclic dodecyl, and other bridged alicyclic hydrocarbon groups. Examples of monocyclic unsaturated hydrocarbon groups include cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, and other monocyclic cycloalkenyl groups. Examples of polycyclic unsaturated hydrocarbon groups include norbornyl, tricyclic decenyl, tetracyclic dodecenyl, and other polycyclic cycloalkenyl groups. Furthermore, bridged alicyclic hydrocarbon groups refer to polycyclic alicyclic hydrocarbon groups in which two non-adjacent carbon atoms constituting the alicyclic ring are bonded together by a linker containing one or more carbon atoms.

[0065] As the R A1 The monovalent aromatic hydrocarbon groups represented by carbon numbers from 6 to 20 include, for example, aryl groups such as phenyl, tolyl, xylyl, naphthyl, and anthracene; and aralkyl groups such as benzyl, phenethyl, and naphthylmethyl.

[0066] As the R A1 Preferably, it is a straight-chain or branched saturated hydrocarbon group with 1 to 20 carbon atoms, or a monovalent alicyclic hydrocarbon group with 3 to 20 carbon atoms.

[0067] As R A2 and R A3 The 3-20 carbon-numbered divalent alicyclic groups that combine with each other and together with the bonded carbon atoms can preferably be formed by removing a hydrogen atom from the 3-20 carbon-numbered monovalent alicyclic hydrocarbon groups.

[0068] As R A2 and R A3 Preferably, it is a monovalent chain hydrocarbon group having 1 to 10 carbon atoms, or R A2 and R A3 The carbon atoms bonded together with each other form a divalent alicyclic group with 3 to 20 carbon atoms, more preferably a monovalent straight-chain hydrocarbon group with 1 to 10 carbon atoms or a divalent alicyclic group with 5 to 10 carbon atoms. As a monovalent straight-chain hydrocarbon group with 1 to 10 carbon atoms or a divalent alicyclic group with 5 to 10 carbon atoms, it is even more preferably methyl, ethyl, isopropyl, tert-butyl, cyclopentanediyl, cyclohexanediyl, or adamantanediyl.

[0069] When m11 is 0, L A1 Preferably, it is a single bond or an aryl dimethyl group. When m11 is 1, L... A1 Preferably, it is alkyldiyl.

[0070] As a structural unit (I), for example, the structural units represented by the following equations (1-1) to (1-14) (hereinafter also referred to as "structural unit (I-1) to structural unit (I-14)") can be listed.

[0071] [Chemistry 4]

[0072]

[0073] [Chemistry 5]

[0074]

[0075] In equations (1-1) to (1-14), R α R A1 ~R A3 This has the same meaning as formula (2). X is a hydroxyl group, halogen atom, carboxyl group, cyano group, nitro group, alkyl group, fluorinated alkyl group, alkoxycarbonyloxy group, acyl group, acyloxy group, or alkoxy group. i and j are each independently an integer from 1 to 4. k and l are 0 or 1. a1 is an integer from 0 to 3. When a1 is 2 or more, multiple Xs are the same or different from each other. a4 is an integer from 1 to 3.

[0076] For i and j, 1 or 2 is preferred. For k and l, 1 is preferred. For R A1 Preferably, it is methyl, ethyl, isopropyl, tert-butyl, phenyl, or iodophenyl. As R A2 and R A3 Preferably, it is methyl, ethyl, or isopropyl. As X, it is preferably a hydroxyl group, an iodine atom, or an alkyl group.

[0077] Furthermore, the polymer (A) may also contain structural units represented by the following formulas (1f) to (2f) as structural units (I).

[0078] [Chemistry 6]

[0079]

[0080] In equations (1f) to (2f), R αf Each can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R βf Each is independently a hydrogen atom or a chain alkyl group having 1 to 5 carbon atoms. h1 is an integer from 1 to 4.

[0081] As the R βf Preferably, it contains hydrogen atoms, methyl groups, or ethyl groups. As h1, it is preferably 1 or 2.

[0082] Specific examples of structural unit (I) can be listed below, but are not limited to these.

[0083] [Chemistry 7]

[0084]

[0085] (where R) α (This has the same meaning as equation (2) above)

[0086] [Chemistry 8]

[0087]

[0088] (where R) α (This has the same meaning as equation (2) above)

[0089] The base polymer (A) may contain one or more structural units (I).

[0090] As a lower limit for the content ratio of the structural unit (I) (the total content ratio in the case of multiple components), it is preferably 5 mol%, more preferably 7 mol%, and even more preferably 10 mol%, relative to all structural units constituting the base polymer (A). As an upper limit for the content ratio, it is preferably 80 mol%, more preferably 70 mol%, and even more preferably 60 mol%. By setting the content ratio of the structural unit (I) within the above range, the patterning properties of the radiosensitive linear composition can be further improved.

[0091] [Structural Unit (II)]

[0092] Structural unit (II) is a structural unit comprising at least one selected from the group consisting of lactone structures, cyclic carbonate structures, sulfonyl lactone structures, and cyclic sulfone structures. By also having structural unit (II), the solubility of the base polymer (A) in the developer can be adjusted, resulting in improved photolithography properties such as resolution of the photosensitive linear composition. Furthermore, the adhesion between the resist pattern formed from the base polymer (A) and the substrate can be improved.

[0093] As a structural unit (II), for example, the structural units represented by the following formulas (T-1) to (T-11) can be listed.

[0094] [Chemistry 9]

[0095]

[0096] In the formula, R L1 It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R L2 ~R L5 Each of the following groups is independently composed of 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 hydroxyl group, a hydroxymethyl group, a dimethylamino group, or a -COOR group. L6 R L6It is a monovalent hydrocarbon group with 1 to 20 carbon atoms. R L4 and R L5 It can also be a divalent alicyclic hydrocarbon group with 3 to 8 carbon atoms, which are bonded together with each other. 2 It can be a single bond or a divalent linker. X is an oxygen atom or a methylene group. k is an integer from 0 to 3. m is an integer from 1 to 3.

[0097] As the R L4 and R L5 The 3-8 carbon-numbered divalent alicyclic hydrocarbon groups that combine with each other and together with these bonded carbon atoms can be represented by R in the above formula (2). A2 and R A3 The carbon atoms in the divalent alicyclic hydrocarbon group with 3 to 20 carbon atoms, which are combined with each other, may be substituted with hydroxyl groups.

[0098] As the R L6 The monovalent hydrocarbon group representing 1 to 20 carbon atoms can preferably be represented by R in formula (2). A1 The monovalent hydrocarbon group represented has 1 to 20 carbon atoms.

[0099] As the L 2 Examples of divalent linkages 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 consisting of one or more of these hydrocarbon groups and at least one of the groups selected from -CO-, -O-, -NH-, and -S-.

[0100] As the L 2 The divalent linear or branched hydrocarbon group with 1 to 10 carbon atoms can preferably be derived from R in formula (2). A1 A group formed by removing one hydrogen atom from a chain hydrocarbon group with 1 to 20 carbon atoms.

[0101] As the L 2 The divalent alicyclic hydrocarbon group with 4 to 12 carbon atoms in the formula (2) can preferably be R from the formula. A1 The radical is formed by removing one hydrogen atom from a monovalent alicyclic hydrocarbon group with 3 to 20 carbon atoms.

[0102] As structural unit (II), these are preferably structural units containing a lactone structure, more preferably structural units containing a norbornene lactone structure, and even more preferably structural units derived from norbornene lactone-based esters of (meth)acrylate.

[0103] The base polymer (A) may contain one or more structural units (II).

[0104] When the base polymer (A) contains the structural unit (II), the lower limit of the content ratio of the structural unit (II) (which is the total content ratio when multiple units are included) relative to all structural units constituting the base polymer (A) is preferably 5 mol%, more preferably 10 mol%, and even more preferably 15 mol%. The upper limit of the content ratio is preferably 80 mol%, more preferably 70 mol%, and even more preferably 60 mol%. By setting the content ratio of the structural unit (II) within the above range, the photosensitive linear composition can further improve photolithographic properties such as resolution and the adhesion between the formed resist pattern and the substrate.

[0105] [Structural Unit (III)]

[0106] In addition to the structural units (I) and (II), the base polymer (A) may also optionally have other structural units. Examples of these other structural units include structural units (III) containing polar groups (excluding those equivalent to structural unit (II)). By also having structural unit (III), the base polymer (A) can adjust its solubility in the developer, thereby improving the photolithographic properties, such as resolution, of the radiosensitive linear composition. Examples of these polar groups include hydroxyl, carboxyl, cyano, nitro, and sulfonamide groups. Hydroxyl and carboxyl groups are preferred, with hydroxyl being more preferred.

[0107] As a structural unit (III), for example, structural units represented by the following formulas can be listed.

[0108] [Chemistry 10]

[0109]

[0110] [Chemistry 11]

[0111]

[0112] In the formula, R K It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0113] When the base polymer (A) contains the structural unit (III), the lower limit of the content ratio of the structural unit (III) relative to all structural units constituting the base polymer is preferably 1 mol%, more preferably 3 mol%, and even more preferably 5 mol%. Furthermore, the upper limit of the content ratio is preferably 80 mol%, more preferably 70 mol%, and even more preferably 65 mol%. By setting the content ratio of the structural unit (III) within the aforementioned range, the lithographic properties, such as resolution, of the photosensitive linear composition can be further improved.

[0114] [Structural Unit (IV)]

[0115] In addition to the structural unit (III) having the aforementioned polar group, the base polymer (A) may also optionally contain structural units derived from hydroxystyrene or structural units having phenolic hydroxyl groups (hereinafter, both will be referred to together as "structural unit (IV)") as other structural units. Structural unit (IV) contributes to improved etch resistance and increased difference in developer solubility (solution contrast) between exposed and unexposed areas. In particular, it is preferably applicable to pattern formation using exposure based on radiation with wavelengths below 50 nm, such as electron beams or EUV. In this case, the polymer preferably has both structural unit (IV) and structural unit (I).

[0116] Structural units derived from hydroxystyrene are represented by formulas (4-1) to (4-3) below, for example, and structural units having phenolic hydroxyl groups are represented by formulas (4-4) to (4-6) below.

[0117] [Chemistry 12]

[0118]

[0119] In equations (4-1) to (4-6), R 41 Each of the following can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y can be a halogen atom, a trifluoromethyl group, a cyano group, an alkyl or alkoxy group having 1 to 6 carbon atoms, or an acyl, acyloxy, or alkoxy carbonyl group having 2 to 7 carbon atoms. Among these, Y is preferably a halogen atom, and more preferably a fluorine atom or an iodine atom. When multiple Y atoms are present, the multiple Y atoms may be identical or different from each other. t is an integer from 0 to 4.

[0120] When obtaining a structural unit (IV), it is preferable to polymerize while the phenolic hydroxyl groups are protected by a protecting group such as a base-dissociating group (e.g., an acyl group), followed by hydrolysis and deprotection, thereby obtaining the structural unit (IV). Alternatively, polymerization of a monomer providing the structural unit (IV) can be carried out without protecting the phenolic hydroxyl groups.

[0121] In the case of a polymer used for exposure to radiation with wavelengths below 50 nm, the lower limit of the content ratio of structural unit (IV) relative to all structural units constituting the base polymer (A) is preferably 10 mol%, more preferably 20 mol%. Furthermore, the upper limit of the content ratio is preferably 80 mol%, more preferably 70 mol%.

[0122] [Other structural units]

[0123] The base polymer (A) may also contain structural units with alicyclic structures represented by the following formula (6) (hereinafter also referred to as "structural unit (VII)") as structural units other than the listed structural units.

[0124] [Chemistry 13]

[0125]

[0126] (In the aforementioned formula (6),

[0127] R 1α It consists of hydrogen atoms, fluorine atoms, methyl groups, or trifluoromethyl groups;

[0128] R 2α (A monovalent alicyclic hydrocarbon group with 3 to 20 carbon atoms)

[0129] In equation (6), R is used as 2α The monovalent alicyclic hydrocarbon group representing 3 to 20 carbon atoms can preferably be represented by R in formula (2). A1 The indicated carbon number is 3 to 20. It is a monovalent alicyclic hydrocarbon group.

[0130] When the base polymer (A) contains the structural unit (VII), the lower limit of the content of the structural unit (VII) relative to all structural units constituting the base polymer is preferably 2 mol%, more preferably 5 mol%, and even more preferably 8 mol%. In addition, the upper limit of the content is preferably 30 mol%, more preferably 20 mol%, and even more preferably 15 mol%.

[0131] (Synthetic methods of basic polymers)

[0132] Basic polymers can be synthesized, for example, by using free radical polymerization initiators, to polymerize monomers that provide each structural unit in a suitable solvent.

[0133] Examples of free radical polymerization initiators include: azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylpentanonitrile), dimethyl 2,2'-azobisisobutyrate, and other azo-based free radical initiators; and peroxide-based free radical initiators such as benzoyl peroxide, tert-butyl hydroperoxide, and cumene hydroperoxide. Among these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferred, and AIBN is more preferred. These free radical initiators can be used alone or in combination of two or more.

[0134] Examples of solvents used in the polymerization include:

[0135] Alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane;

[0136] Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decahydronaphthalene, and norbornene;

[0137] Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, and cumene;

[0138] Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, and chlorobenzene;

[0139] Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, isobutyl acetate, and methyl propionate;

[0140] Lactones such as γ-butyrolactone and δ-valerolactone;

[0141] Ketones such as acetone, 2-butanone, 4-methyl-2-pentanone, 2-heptanone, and cyclohexanone;

[0142] Ethers such as propylene glycol monomethyl ether, dimethoxyethane, diethoxyethane, tetrahydrofuran, 1,4-dioxane, and other cyclic ethers;

[0143] Alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-methoxy-2-propanol, and 4-methyl-2-pentanol;

[0144] Solvents such as diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), and dipropylene glycol monomethyl ether acetate are polyol partial ether acetates.

[0145] The solvents used in these polymerizations can be a single solvent or two or more solvents used in combination.

[0146] The reaction temperature in the polymerization is typically 40°C to 150°C, preferably 50°C to 120°C. The reaction time is typically 1 hour to 48 hours, preferably 1 hour to 24 hours.

[0147] The molecular weight of the base polymer is not particularly limited, but as a lower limit for the converted weight average molecular weight (Mw) of polystyrene obtained based on gel permeation chromatography (GPC), it is preferably 2,000, more preferably 3,000, further preferably 4,000, and particularly preferably 4,500. As an upper limit for Mw, it is preferably 30,000, more preferably 20,000, further preferably 12,000, and particularly preferably 10,000. By setting the Mw of the base polymer within the aforementioned range, good developability can be imparted to the obtained resist film.

[0148] The ratio (Mw / Mn) of the base polymer to the equivalent number average molecular weight (Mn) of polystyrene obtained based on GPC is typically 1 or more and 5 or less, preferably 1 or more and 3 or less, and more preferably 1 or more and 2 or less.

[0149] The Mw and Mn values ​​of the polymers in this specification are values ​​determined using gel permeation chromatography (GPC) under the following conditions.

[0150] GPC tubing: 2 G2000HXL, 1 G3000HXL, 1 G4000HXL (all manufactured by Tosoh Corporation)

[0151] Column temperature: 40℃

[0152] Dissolution solvent: Tetrahydrofuran

[0153] Flow rate: 1.0 mL / min

[0154] Sample concentration: 1.0% by mass

[0155] Sample injection volume: 100 μL

[0156] Detector: Differential refractometer

[0157] Standard material: Monodisperse polystyrene

[0158] The proportion of the base polymer (A) relative to the total solid content of the radiosensitive linear composition is preferably 60% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 70% by mass or more.

[0159] <Radiosensitive linear acid generator (B)>

[0160] The radiosensitive linear acid generator (B) is represented by the following formula (1).

[0161] [Chemistry 14]

[0162]

[0163] (In the above formula (1),

[0164] R 1 It can be a hydrogen atom, nitro group, hydroxyl group, cyano group, carboxyl group, thiol group, halogen atom, or monovalent organic group; in R 1 In the case of multiple Rs, multiple Rs 1 They are the same or different;

[0165] R 2 It is a monovalent organic group with 1 to 40 carbon atoms;

[0166] m is an integer from 1 to 5;

[0167] M + (It is a monovalent onium cation)

[0168] The radiosensitive linear acid generator (B) has the following function: the acid generated by exposure causes the acid dissociation groups of the polymer (A) to dissociate and generate carboxyl groups, etc.

[0169] As R 1 Examples of monovalent organic groups include: monovalent hydrocarbon groups with 1 to 20 carbon atoms, groups having divalent heteroatoms between carbon atoms or at the end of the carbon chain of the hydrocarbon group, groups formed by substituting some or all of the hydrogen atoms of the hydrocarbon group with a monovalent heteroatom group, or combinations thereof.

[0170] As the monovalent hydrocarbon group with 1 to 20 carbon atoms in the organic group, R of formula (2) can preferably be used. A1 The monovalent hydrocarbon group represented has 1 to 20 carbon atoms.

[0171] Examples of heteroatoms constituting the monovalent or divalent heteroatom-containing bases include: oxygen, nitrogen, sulfur, phosphorus, silicon, and halogen atoms. Examples of halogen atoms include: fluorine, chlorine, bromine, and iodine atoms.

[0172] Examples of monovalent heteroatom-containing groups include: hydroxyl, carboxyl, hydrogen sulfide, cyano, nitro, halogen atom, etc.

[0173] Examples of divalent heteroatom-containing bases include: -CO-, -C(=O)O-, -CS-, -NH-, -O-, -S-, -SO-, -SO2-, or combinations thereof.

[0174] As the R 1 Preferably, it consists of a halogen atom, a hydrogen atom, and a monovalent hydrocarbon group having 1 to 20 carbon atoms. From the viewpoint of reducing the content of fluorine atoms, it is more preferably a hydrogen atom and a monovalent hydrocarbon group having 1 to 10 carbon atoms.

[0175] As the R 2 The monovalent organic group representing carbon numbers from 1 to 40 can preferably be the R group. 1 The monovalent organic group it represents.

[0176] The R 2 The monovalent organic group represented is preferably selected from ester bonds (-C(=O)O- or -OC(=O)-) and amide bonds (-C(=O)NR-). L At least one bond from the group consisting of -), ether bond (-O-), sulfonyl bond (-SO2-), carbonyl bond (-C(=O)-), thioether bond (-S-), and carbonate bond (-OC(=O)O-). The R in the amide bond... L It is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. Preferably, it includes at least one bond selected from the group consisting of ester, amide, and carbonate bonds, more preferably including ester and carbonate bonds. (By R) 2 The monovalent organic group represented has the aforementioned bond, and the radiosensitive linear acid generator (B) undergoes high polarization. In positive resists, this improves solubility in the developer, resulting in an increased LWR, which is therefore preferred. Furthermore, in the case of negative resists, the high polarization of the radiosensitive linear acid generator (B) enhances the dissolution inhibition effect on the developer, resulting in an increased LWR, which is also preferred.

[0177] The R 2 The monovalent organic group can be a structure containing only a chain structure (excluding a cyclic structure) or a structure containing a cyclic structure.

[0178] The ring structure can be a single ring, multiple rings, or a combination thereof. Furthermore, the ring structure can be an alicyclic structure, an aromatic ring structure, a heterocyclic structure, or a combination thereof. In the case of combinations, the ring structures can be formed by chain-like bonding, or two or more ring structures can form a condensed ring structure or a bridged ring structure. 2 The number of ring structures can be one or more, or even two or more.

[0179] Examples of alicyclic structures include monovalent alicyclic hydrocarbon groups with 3 or more but less than 20 carbon atoms. Preferably, R from formula (2) is used as a monovalent alicyclic hydrocarbon group with 3 to 20 carbon atoms. A1 The indicated carbon number is 3 to 20. It is a monovalent alicyclic hydrocarbon group.

[0180] Examples of aromatic ring structures include monovalent aromatic hydrocarbon groups with 6 to 20 carbon atoms. Preferably, the R group of formula (2) is used as a monovalent aromatic hydrocarbon group with 6 to 20 carbon atoms. A1 The groups represented are monovalent aromatic hydrocarbon groups with 6 to 20 carbon atoms.

[0181] Examples of heterocyclic structures include groups formed by removing a hydrogen atom from an aromatic heterocyclic structure and groups formed by removing a hydrogen atom from an alicyclic heterocyclic structure. Aromatic structures of five-membered rings that acquire aromaticity by introducing heteroatoms are also included in heterocyclic structures.

[0182] Examples of aromatic heterocyclic structures include:

[0183] Aromatic heterocyclic structures containing oxygen atoms, such as furan, pyran, benzofuran, and benzopyran;

[0184] Aromatic heterocyclic structures containing nitrogen atoms, such as pyrrole, imidazole, pyridine, pyrimidine, pyrazine, indole, quinoline, isoquinoline, acridine, phenazine, and carbazole;

[0185] Thiophene and other aromatic heterocyclic structures containing sulfur atoms;

[0186] Aromatic heterocyclic structures containing multiple heteroatoms, such as thiazoles, benzothiazoles, thiazides, and oxazines.

[0187] Examples of alicyclic heterocyclic structures include:

[0188] Alicyclic heterocyclic structures containing oxygen atoms, such as oxacyclopropane, oxacyclobutane, tetrahydrofuran, tetrahydropyran, dioxane, and dioxane.

[0189] Alicyclic and heterocyclic structures containing nitrogen atoms, such as aziridine, pyrrolidine, piperidine, and piperazine;

[0190] Thietane, thiocyclopentane, thiane, and other alicyclic heterocyclic structures containing sulfur atoms;

[0191] Morpholine, 1,2-oxathionecyclopentane, 1,3-oxathionecyclopentane, and other alicyclic and heterocyclic structures containing multiple heteroatoms;

[0192] Lactone structure, cyclic carbonate structure and sulfonolactone structure, etc.

[0193] Heterocyclic structures include lactone structures, cyclic carbonate structures, sulfonyl lactone structures, cyclic acetals, or combinations thereof.

[0194] Examples of the chain-like structure include monovalent chain-like organic groups having 1 to 30 carbon atoms. The R group is preferably used as a monovalent chain-like organic group having 1 to 30 carbon atoms. 1 The monovalent organic group represented has a chain structure (excluding cyclic structures).

[0195] m is an integer from 1 to 5, preferably an integer from 1 to 3, and more preferably 1.

[0196] The preferred form of the radiosensitive linear acid generator (B) is represented by the following formula (1-1).

[0197] [Chemistry 15]

[0198]

[0199] (In the above formula (1-1),

[0200] R 1 m, M + It has the same meaning as the above formula (1);

[0201] R 11 and R 12 Each can be independently a hydrogen atom, nitro group, hydroxyl group, cyano group, carboxyl group, thiol group, halogen atom, or monovalent organic group; in R 11 and R 12 In the case of multiple Rs, multiple Rs 11 and R 12 They are the same or different;

[0202] L 1 It is at least one linker selected from the group consisting of ester bond, amide bond, ether bond, sulfonyl bond, carbonyl bond, thioether bond and carbonate bond;

[0203] m1 is an integer from 0 to 5;

[0204] m2 is 0 or 1;

[0205] R 13 (A monovalent organic group with 1 to 15 carbon atoms)

[0206] As the R 13 The monovalent organic group representing carbon 1 to 15 can preferably be the R group. 1 The corresponding number of carbons in the monovalent organic group.

[0207] m1 is an integer from 0 to 5, preferably an integer from 0 to 3.

[0208] m2 can be 0 or 1, preferably 1.

[0209] While there is no limitation on the specific examples of the anion of the radiosensitive linear acid generator (B), structures such as those in formulas (1-1-1) to (1-1-48) can be listed as examples.

[0210] [Chemistry 16]

[0211]

[0212] [Chemistry 17]

[0213]

[0214] [Chemistry 18]

[0215]

[0216] [Chemistry 19]

[0217]

[0218] [Chemistry 20]

[0219]

[0220] [Chemistry 21]

[0221]

[0222] In the above formula (1), M is used as... + The onium cation referred to is preferably a radiosensitive linear onium cation, such as radiodegradable onium cations containing elements such as S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, and Bi. Examples of radiodegradable onium cations include: sulfonium cations, tetrahydrothiophene onium cations, zirconia cations, phosphonium cations, diazoonium cations, and pyridinium cations. Among these, sulfonium cations or zirconia cations are preferred. Sulfonium cations or zirconia cations are preferably represented by the following formulas (X-1) to (X-6).

[0223] [Chemistry 22]

[0224]

[0225] In the formula (X-1), R a1 R a2 and R a3 Each of the following is independently 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, an substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, a hydroxyl group, a halogen atom, or -OSO2-R. P -SO2-R Q -SR T -O-, -CO-, or combinations thereof, or a ring structure formed by the bonding of two or more of these groups. The ring structure may contain heteroatoms such as O or S between the carbon-carbon bonds forming the framework. R P R Q and R TEach of the following 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 independently integers from 0 to 5. In R a1 ~R a3 and R P R Q and R T In the case of multiple Rs, multiple Rs a1 ~R a3 and R P R Q and R T They can be the same or different.

[0226] In the formula (X-2), R b1 It is a straight-chain or branched alkyl group, or alkoxy group, alkoxyalkyloxy group, acyl group, or aromatic hydrocarbon group, or hydroxyl group, with 1 to 20 carbon atoms, substituted or unsubstituted, having 1 to 20 carbon atoms. k It can be 0 or 1. In n k When k is 0, k4 is an integer from 0 to 4, and in n k When k is 1, k4 is an integer from 0 to 7. In R b1 In the case of multiple Rs, multiple Rs b1 They can be the same or different. Additionally, multiple Rs... b1 It can also manifest as a ring structure formed by interconnected elements. R b2 It is a straight-chain or branched alkyl group with 1 to 7 carbon atoms, either substituted or unsubstituted, or an aromatic hydrocarbon group with 6 or 7 carbon atoms, either substituted or unsubstituted. C It is a single-bond or divalent linkage base. k5 is an integer from 0 to 4. In R b2 In the case of multiple Rs, multiple Rs b2 They can be the same or different. Additionally, multiple Rs... b2 It can also be represented as a ring structure formed by mutual combination. q is an integer from 0 to 3. The formula includes S. + The ring structure may contain heteroatoms such as O or S between the carbon-carbon bonds that form the framework.

[0227] In the formula (X-3), R c1 R c2 and R c3 Each is independently a straight-chain or branched alkyl group having 1 to 12 carbon atoms, either substituted or unsubstituted.

[0228] In the aforementioned equation (X-4), R g1It is a straight-chain or branched alkyl or alkoxy group with 1 to 20 carbon atoms, substituted or unsubstituted, an acyl group with 2 to 8 carbon atoms, substituted or unsubstituted, an aromatic hydrocarbon group with 6 to 8 carbon atoms, or a hydroxyl group. k2 It can be 0 or 1. In n k2 When k is 0, k10 is an integer from 0 to 4, and in n k2 When k is 1, k10 is an integer from 0 to 7. In R g1 In the case of multiple Rs, multiple Rs g1 They can be the same or different. Additionally, multiple Rs... g1 It can also manifest as a ring structure formed by interconnected elements. R g2 and R g3 Each group is independently 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; or a halogen atom, or a ring structure formed by the combination of these groups. k11 and k12 are independently integers from 0 to 4. In R g2 and R g3 In the case of multiple Rs, multiple Rs g2 and R g3 They can be the same or different.

[0229] In the aforementioned formula (X-5), R d1 and R d2 Each group can be independently a substituted or unsubstituted linear or branched alkyl group, alkoxy or alkoxycarbonyl group, substituted or unsubstituted aromatic hydrocarbon group with 6 to 12 carbon atoms, halogen atom, halogenated alkyl group with 1 to 4 carbon atoms, nitro group, or a ring structure formed by the combination of two or more of these groups. k6 and k7 are independently integers from 0 to 5. In R d1 and R d2 In the case of multiple Rs, multiple Rs d1 and R d2 They can be the same or different.

[0230] In the aforementioned equation (X-6), R e1 and R e2 Each of the following 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 independently integers from 0 to 4.

[0231] While not limited to specific examples of the radiosensitive linear onyx cations, structures such as those described in formulas (1-2-1) to (1-2-66) can be listed as examples.

[0232] [Chemistry 23]

[0233]

[0234] (In the formula, tBu represents tert-butyl and Me represents methyl)

[0235] [Chemistry 24]

[0236]

[0237] [Chemistry 25]

[0238]

[0239] [Chemistry 26]

[0240]

[0241] As a radiosensitive linear acid generator (B), it can be obtained by appropriately combining the anion with the radiosensitive linear ononium cation. As specific examples, although there is no particular limitation, structures such as those of formulas (1-3-1) to (1-3-53) can be listed as examples.

[0242] [Chemistry 27]

[0243]

[0244] [Chemistry 28]

[0245]

[0246] [Chemistry 29]

[0247]

[0248] [Chemistry 30]

[0249]

[0250] [Chemistry 31]

[0251]

[0252] [Chemistry 32]

[0253]

[0254] The lower limit of the content of the radiosensitive linear acid generator (B) (total of the radiosensitive linear acid generator (B) in the case of multiple radiosensitive linear acid generators (B)) relative to 100 parts by mass of polymer (A) is preferably 1 part by mass, more preferably 3 parts by mass, and even more preferably 5 parts by mass. The upper limit of the content is preferably 30 parts by mass, more preferably 25 parts by mass. The content of the radiosensitive linear acid generator (B) can be appropriately selected according to the type of polymer used, exposure conditions, or required sensitivity. As a result, excellent sensitivity, LWR, pattern rectangularity, CDU, pattern circularity, and development defect performance can be achieved during resist pattern formation.

[0255] The radiosensitive linear composition may also be used in combination with the radiosensitive linear acid generator (B) and other radiosensitive linear acid generators (e.g., the radiosensitive linear acid generator (P1) or the intramolecular salt compound (P2) described below).

[0256] <Radiosensitive linear acid generator (P1)>

[0257] As the radiosensitive linear acid generator (P1), examples include onium salt compounds (P1) represented by the following formula (P1) (except for those equivalent to the radiosensitive linear acid generator (B)).

[0258] [Chemistry 33]

[0259]

[0260] (In formula (P1),

[0261] R 40 Monovalent organic groups with 1 to 40 carbon atoms

[0262] R f21 and R f22 Each is independently a hydrogen atom, a cyano group, a fluorine atom, or a monovalent fluorinated hydrocarbon group; wherein, the R group is bonded to the carbon atom adjacent to the sulfonate anion. f21 and R f22 At least one of them is a fluorine atom, a monovalent fluorinated hydrocarbon group, or a cyano group; in R f21 and R f22 In the case of multiple Rs, multiple Rs f21 and R f22 They are the same or different;

[0263] n is an integer from 1 to 4;

[0264] Z2 + (for radiosensitive linear onon cations)

[0265] As R 40 The monovalent organic group representing carbon 1 to 40 can preferably be R of formula (1).2 and R 3 The monovalent organic group it represents.

[0266] As R f21 and R f22 The monovalent fluorinated hydrocarbon group represented can be listed as R in formula (2). A1 The groups represented by monovalent hydrocarbon groups with 1 to 20 carbon atoms are formed by replacing some or all of the hydrogen atoms with fluorine atoms.

[0267] While there are no specific examples of anions of onium salt compounds (P1), structures such as those described below can be listed as examples.

[0268] [Chemistry 34]

[0269]

[0270] [Chemistry 35]

[0271]

[0272] [Chemistry 36]

[0273]

[0274] [Chemistry 37]

[0275]

[0276] [Chemistry 38]

[0277]

[0278] While there is no limitation on the specific example of a radiosensitive linear ononium cation of ononium salt compound (P1), the structure listed as a specific example of a radiosensitive linear ononium cation of formula (1) may preferably be adopted.

[0279] As an onium salt compound (P1), structures formed by any combination of the anion and the radiosensitive linear onium cation can be listed. Examples of onium salt compounds (P1) represented by the following formulas can be cited.

[0280] [Chemistry 39]

[0281]

[0282] [Chemistry 40]

[0283]

[0284] Alternatively, as a radiosensitive linear acid generator other than the onium salt compound (P1), an intramolecular salt compound (P2) containing both cations and anions within the same molecule, represented by the following formula (Y-1), may also be used.

[0285] [Chemistry 41]

[0286]

[0287] In the formula (Y-1), R a1 R a2 R a3 k1, k2, and k3 have the same meaning as in equation (X-1). a1 It is a single-bonded or divalent linkage base. X a X b Each can be a hydrogen atom, a fluorine atom, or a trifluoromethyl atom, independently. k11 is an integer from 1 to 4.

[0288] As the divalent linker, the L of equations (T-1) to (T-11) can preferably be used, for example. 2 The divalent linker or the divalent heteroatom-containing base represented.

[0289] While there is no limitation on the specific example of the radiosensitive linear onyx cation represented by the formula (Y-1), the structures of formulas (1-4-1) to (1-4-10) can be listed as examples.

[0290] [Chemistry 42]

[0291]

[0292] When the radiosensitive linear composition contains a radiosensitive linear acid generator (P1), the lower limit of the content of the radiosensitive linear acid generator (P1) relative to 100 parts by mass of polymer (A) (the total of these in the case of multiple onium salt compounds (P1) and intramolecular salt compounds (P2)) is preferably 0.5 parts by mass, more preferably 1 part by mass, and even more preferably 1.5 parts by mass. The upper limit of the content is preferably 50 parts by mass, more preferably 40 parts by mass, even more preferably 30 parts by mass, and particularly preferably 25 parts by mass. The content of radiosensitive linear acid generators other than radiosensitive linear acid generator (B) can be appropriately selected according to the type of polymer used, exposure conditions, or required sensitivity.

[0293] <Acid Diffusion Control Agent (D)>

[0294] The radiosensitive linear composition may also contain an acid diffusion control agent (D) if necessary. The acid diffusion control agent (D) has the following effects: it controls the diffusion of acid generated by the radiosensitive linear acid generator during exposure into the resist film, and suppresses undesirable chemical reactions in non-exposed areas. Furthermore, the storage stability of the obtained radiosensitive linear composition is improved. Moreover, the resolution of the resist pattern is further improved, and linewidth variations in the resist pattern caused by changes in storage time from exposure to development can be suppressed, thereby obtaining a radiosensitive linear composition with excellent process stability.

[0295] Examples of acid diffusion control agents (D) include: compounds represented by the following formula (7) (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)"), compounds containing amide groups, urea compounds, nitrogen-containing heterocyclic compounds, etc.

[0296] [Chemistry 43]

[0297]

[0298] In equation (7), R 22 R 23 and R 24 Each of the following 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.

[0299] Examples of nitrogen-containing compounds (I) include: monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; trialkylamines such as triethylamine and tripentylamine; aromatic amines such as aniline and 2,6-diisopropylaniline.

[0300] Examples of nitrogen-containing compounds (II) include ethylenediamine, N,N,N',N'-tetramethylethylenediamine, etc.

[0301] Examples of nitrogen-containing compounds (III) include polyamine compounds such as polyethyleneimine and polyallylamine; polymers such as dimethylaminoethylacrylamide.

[0302] Examples of compounds containing an amide group include: formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone, etc.

[0303] Examples of urea compounds include: urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tributylthiourea, etc.

[0304] 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.

[0305] Alternatively, compounds with acid-dissociable groups may be used as the nitrogen-containing organic compounds mentioned above. Examples of such nitrogen-containing organic compounds with acid-dissociable groups include: N-tert-butoxycarbonylpiperidine, N-tert-butoxycarbonylimidazolium, N-tert-butoxycarbonylbenzimidazole, N-tert-butoxycarbonyl-2-phenylbenzimidazole, N-(tert-butoxycarbonyl)di-n-octylamine, N-(tert-butoxycarbonyl)diethanolamine, N-(tert-butoxycarbonyl)dicyclohexylamine, N-(tert-butoxycarbonyl)diphenylamine, N-tert-butoxycarbonyl-4-hydroxypiperidine, N-tert-butoxycarbonyl-4-acetoxypiperidine, and N-tert-pentyloxycarbonyl-4-hydroxypiperidine.

[0306] Additionally, as the acid diffusion control agent (D), an onium salt compound (d) that produces an acid with a higher pKa than the acid produced by the radiosensitive linear acid generator can preferably be used. The acid produced by the onium salt compound (d) is a weak acid that does not induce the dissociation of the acid dissociative groups under conditions that cause dissociation of the acid dissociative groups in the polymer. Furthermore, in this specification, the term "dissociation" of the acid dissociative groups refers to dissociation that occurs during baking after exposure at 110°C for 60 seconds.

[0307] The onium salt compound (d) is preferably represented by the following formulas (8-1) to (8-4).

[0308] [Chemistry 44]

[0309]

[0310] In equations (8-1) and (8-2), J + It is a sulfonium cation, U + It is a monazine cation. The E in formulas (8-1) and (8-2) - and Q - Each independently selects the option R. 8 SO3 - R 8 COO - and (R) 8 SO2)N - At least one of the groups formed, more preferably R 8COO - Additionally, examples include compounds represented by formula (8-3) containing both a sulfonium cation and an anion within the same molecule, or compounds represented by formula (8-4) containing both a monazonium cation and an anion within the same molecule. In formulas (8-3) and (8-4), J' + U' is a monovalent group with a sulfonium cation structure. + It is a monovalent group having a monazonium cation structure. E' in formulas (8-3) and (8-4) - and Q' - Each independently selects the free choice -R 81 SO3 - -R 81 COO - and -R 81 SO2N - SO2R 8 At least one of the groups formed, more preferably -R 81 COO - The R 8 As a monovalent organic group, the R 81 It is a single bond or a divalent organic group.

[0311] As the monovalent organic group, R of formula (1) can preferably be used. 2 and R 3 The monovalent organic group it represents.

[0312] As the divalent organic group, R from formula (1) can preferably be used. 2 and R 3 The radical represented is formed by removing one hydrogen atom from a monovalent organic radical.

[0313] Examples of compounds represented by the following formulas can be cited as examples of onium salt compounds (d).

[0314] [Chemistry 45]

[0315]

[0316] [Chemistry 46]

[0317]

[0318] [Chemistry 47]

[0319]

[0320] The onium salt compound (d) can also be synthesized by existing methods, particularly salt exchange reactions. Other existing acid diffusion control agents besides those described can also be used, provided that the effects of the invention are not compromised.

[0321] These acid diffusion control agents (D) can be used alone or in combination of two or more. The lower limit of the content (total in multiple cases) of the acid diffusion control agent (D) relative to 100 parts by mass of the polymer (A) is preferably 0.1 parts by mass, more preferably 0.5 parts by mass, and even more preferably 1 part by mass. The upper limit of the content is preferably 50 parts by mass, more preferably 40 parts by mass, and even more preferably 30 parts by mass. This results in excellent sensitivity or CDU during resist pattern formation.

[0322] <Other Polymers>

[0323] The radiosensitive linear composition of this embodiment may also include a polymer with a higher fluorine atom mass content than the base polymer (hereinafter also referred to as a "high fluorine content polymer") as another polymer. When the radiosensitive linear composition contains a high fluorine content polymer, it may be more concentrated on the surface of the resist film relative to the base polymer. As a result, the water repellency of the resist film surface during immersion exposure can be improved, or the surface modification of the resist film or the control of the distribution of the intrafilm composition can be achieved during EUV exposure.

[0324] As a high-fluorine-content polymer, it is preferred to have, for example, the structural unit represented by the following formula (5) (hereinafter also referred to as "structural unit (V)"), and may also have structural unit (I) or structural unit (III) in the base polymer as needed.

[0325] [Chemistry 48]

[0326]

[0327] In equation (5), R 73 It can be a hydrogen atom, a methyl group, or a trifluoromethyl group. G L It is a single bond, an alkyl group having 1 to 5 carbon atoms, an oxygen atom, a sulfur atom, -COO-, -OCO-, -SO2ONH-, -CONH-, -OCONH-, or a combination thereof. 74 It is a monovalent fluorinated chain hydrocarbon group with 1 to 20 carbon atoms or a monovalent fluorinated alicyclic hydrocarbon group with 3 to 20 carbon atoms.

[0328] As the R 73 From the viewpoint of providing copolymerization of the monolithic structural unit (V), hydrogen atoms and methyl groups are preferred, and methyl groups are more preferred.

[0329] As the G L From the viewpoint of providing copolymerization of the monolithic structural unit (V), it is preferred to combine at least one of single bond, -COO-, -COO- and -OCO- with an alkyl diene having 1 to 5 carbon atoms, more preferably -COO-.

[0330] As the R 74 The monovalent fluorinated chain hydrocarbon group represented by carbon 1 to 20 can be exemplified by those formed by substituting some or all of the hydrogen atoms of a straight-chain or branched alkyl group having carbon 1 to 20 carbon atoms with fluorine atoms.

[0331] As the R 74 The monovalent fluorinated alicyclic hydrocarbon groups with 3 to 20 carbon atoms represented can be those formed by replacing some or all of the hydrogen atoms in monocyclic or polycyclic hydrocarbon groups with 3 to 20 carbon atoms with fluorine atoms.

[0332] As the R 74 Preferably, it is a fluorinated chain hydrocarbon group, and more preferably a fluorinated alkyl group.

[0333] When a high-fluorine polymer has structural units (V), the lower limit of the content ratio of structural units (V) relative to all structural units constituting the high-fluorine polymer is preferably 40 mol%, more preferably 50 mol%, and even more preferably 55 mol%. Furthermore, the upper limit of the content ratio is preferably 90 mol%, more preferably 85 mol%, and even more preferably 80 mol%. By setting the content ratio of structural units (V) within the aforementioned range, the mass content of fluorine atoms in the high-fluorine polymer can be more appropriately adjusted, further promoting the biased presence on the surface of the resist film. As a result, the water repellency of the resist film during immersion exposure can be further improved.

[0334] High-fluorine polymers may also have fluorine-containing structural units (hereinafter also referred to as structural units (VI)) as represented by the following formula (f-2), either together with or in place of structural unit (V). By having structural units (f-2) in high-fluorine polymers, the solubility in alkaline developers is improved, which can suppress the generation of development defects.

[0335] [Chemistry 49]

[0336]

[0337] Structural unit (VI) is broadly classified into two cases: one with a base-soluble group (x) and the other with a group (y) that dissociates under the action of a base and has increased solubility in alkaline developing solutions (hereinafter also referred to as "base-dissociative group"). Both (x) and (y) are common, and in equation (f-2), R... C It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R D It is a single bond, a (s+1) valence hydrocarbon group with 1 to 20 carbon atoms, and the R of the hydrocarbon group E The terminal bonds on the side contain oxygen atoms, sulfur atoms, and -NR. ddA structure consisting of a carbonyl group, -COO-, -OCO-, or -CONH-, or a structure in which a portion of the hydrogen atom of the hydrocarbon group is substituted by an organic group having a heteroatom. dd It consists of a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. s is an integer from 1 to 3.

[0338] When structural unit (VI) has a base-soluble group (x), R F A is a hydrogen atom. 1 For oxygen atoms, -COO- or -SO2O- . Indicates the bond in R F The part. W 1 It is a single bond, a hydrocarbon group with 1 to 20 carbon atoms, or a divalent fluorinated hydrocarbon group. In A... 1 In the case of oxygen atoms, W 1 For in A 1 The bonded carbon atom has a fluorine atom or a fluorinated hydrocarbon group of fluorine alkyl group. R E It is a single bond or a divalent organogroup with 1 to 20 carbon atoms. When s is 2 or 3, multiple R... E W 1 A 1 and R F They can be the same or different. By having a (x) alkali-soluble group in the structural unit (VI), the affinity for alkaline developers can be improved, and development defects can be suppressed. As the structural unit (VI) having the (x) alkali-soluble group, A is particularly preferred. 1 It is an oxygen atom and W 1 The case is 1,1,1,3,3,3-hexafluoro-2,2-methanediyl.

[0339] When the structural unit (VI) has a (y) base-dissociable group, R F A is a monovalent organic group with 1 to 30 carbon atoms. 1 For oxygen atoms, -NR aa -、-COO- -OCO- or -SO2O- R aa It consists of hydrogen atoms or monovalent hydrocarbon groups with 1 to 10 carbon atoms. Indicates the bond in R F The part. W 1 It is a single bond or a divalent fluorinated hydrocarbon group with 1 to 20 carbon atoms. R E It is a single bond or a divalent organogroup with 1 to 20 carbon atoms. In A 1 -COO- -OCO- or -SO2O- In the case of W 1 Or R F In relation to A 1 The bonded carbon atom or the adjacent carbon atom has a fluorine atom. In A 1 In the case of oxygen atoms, W 1 R E For a single bond, R D R is a hydrocarbon group with 1 to 20 carbon atoms. E The structure formed by the terminal bond of a carbonyl group on the side, R F It is an organic group containing fluorine atoms. When s is 2 or 3, multiple R... E W 1 A 1 and R F They can be the same or different. By having a (y) alkali-dissociating group in the structural unit (VI), the surface of the resist film changes from hydrophobic to hydrophilic during the alkaline developing process. As a result, the affinity for the developer can be significantly improved, and developing defects can be suppressed more effectively. As the structural unit (VI) having the (y) alkali-dissociating group, A is particularly preferred. 1 -COO- And R F or W 1 Or both of these contain fluorine atoms.

[0340] As R C From the viewpoint of providing copolymerization of the monolithic structural unit (VI), hydrogen atoms and methyl groups are preferred, and methyl groups are more preferred.

[0341] In R E When the organic group is divalent, it is preferably a group having a lactone structure, more preferably a group having a polycyclic lactone structure, and even more preferably a group having a norbornene lactone structure.

[0342] When the high-fluorine polymer has structural unit (VI), the lower limit of the content ratio of structural unit (VI) relative to all structural units constituting the high-fluorine polymer is preferably 40 mol%, more preferably 50 mol%, and even more preferably 55 mol%. Furthermore, the upper limit of the content ratio is preferably 95 mol%, more preferably 90 mol%, and even more preferably 85 mol%. By setting the content ratio of structural unit (VI) within the aforementioned range, the water repellency of the resist film during immersion exposure can be further improved, and development defects can be suppressed.

[0343] [Other structural units]

[0344] In addition to structural units (I) or (III) in the base polymer, high-fluorine polymers may also contain structural units (VII) represented by formula (6) as structural units other than the listed structural units.

[0345] In the case where the high-fluorine polymer contains structural unit (I) or structural unit (III), the proportion of each structural unit in the high-fluorine polymer can preferably be the proportion described in the description of the base polymer.

[0346] When the high-fluorine polymer contains the structural unit (VII), the lower limit of the content of the structural unit (VII) relative to all structural units constituting the high-fluorine polymer is preferably 10 mol%, more preferably 20 mol%, and even more preferably 30 mol%. Furthermore, the upper limit of the content is preferably 60 mol%, more preferably 50 mol%, and even more preferably 45 mol%.

[0347] The lower limit of Mw for the high-fluorine content polymer is preferably 2,000, more preferably 3,000, further preferably 4,000, and particularly preferably 5,000. Furthermore, the upper limit of Mw is preferably 30,000, more preferably 20,000, further preferably 10,000, and particularly preferably 8,000.

[0348] The lower limit of the Mw / Mn ratio for high-fluorine polymers is typically 1, more preferably 1.1. Furthermore, the upper limit of the Mw / Mn ratio is typically 5, preferably 3, and more preferably 2.

[0349] When the radiosensitive linear composition contains a high-fluorine polymer, the content of the high-fluorine polymer is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 1.5 parts by mass or more, and particularly preferably 2 parts by mass or more, relative to 100 parts by mass of the base polymer. Furthermore, it is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, even more preferably 8 parts by mass or less, and particularly preferably 6 parts by mass or less.

[0350] By setting the content of the high-fluorine polymer within the aforementioned range, the high-fluorine polymer can be more effectively biased towards the surface of the resist film. As a result, the water repellency of the resist film surface during immersion exposure can be improved, or surface modification or control of the composition distribution within the resist film can be achieved during EUV exposure. The radiosensitive linear composition may contain one or more high-fluorine polymers.

[0351] (Synthesis methods of high fluorine content polymers)

[0352] High-fluorine polymers can be synthesized using the same methods as the base polymers.

[0353] <Solvent (E)>

[0354] The radiosensitive linear composition of this embodiment contains a solvent (E). The solvent (E) is not particularly limited as long as it is a solvent capable of dissolving or dispersing at least the polymer (A), the radiosensitive linear acid generator (B), and, if necessary, an acid diffusion control agent (D).

[0355] Examples of solvents include: alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, and hydrocarbon solvents.

[0356] Examples of alcohol-based solvents include:

[0357] Monohydric alcohol solvents with 1 to 18 carbon atoms, such as isopropanol, 4-methyl-2-pentanol, 3-methoxybutanol, n-hexanol, 2-ethylhexanol, furfuryl alcohol, cyclohexanol, 3,3,5-trimethylcyclohexanol, and diacetone alcohol.

[0358] Polyol solvents with 2 to 18 carbon atoms, such as ethylene glycol, 1,2-propanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, and tripropylene glycol.

[0359] Polyol partial ether solvents, etc., are formed by etherifying a portion of the hydroxyl groups in the polyol solvent.

[0360] In this embodiment, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, methyl 2-hydroxyisobutyrate, isopropyl 2-hydroxyisobutyrate, isobutyl 2-hydroxyisobutyrate, and n-butyl 2-hydroxyisobutyrate are also included in the alcohol solvent.

[0361] Examples of ether-based solvents include:

[0362] Dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether;

[0363] Tetrahydrofuran, tetrahydropyran, and other cyclic ether solvents;

[0364] Ether solvents containing aromatic rings, such as diphenyl ether and anisole (methyl phenyl ether);

[0365] Polyol ether solvents, etc., are formed by etherifying the hydroxyl groups of the polyol solvent.

[0366] Examples of ketone solvents include: acetone, butanone, methyl isobutyl ketone, and other chain-like ketone solvents.

[0367] Cyclopentanone, cyclohexanone, methylcyclohexanone, and other cyclic ketone solvents:

[0368] 2,4-Pentanedione, acetone, acetophenone, etc.

[0369] Examples of amide solvents include cyclic amide solvents such as N,N'-dimethylimidazolium ketone and N-methylpyrrolidone.

[0370] N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropionic acid, and other chain amide solvents.

[0371] Examples of ester-based solvents include:

[0372] Monocarboxylic acid ester solvents such as n-butyl acetate;

[0373] Diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and other polyol partial ether acetates are solvents;

[0374] Lactone solvents such as γ-butyrolactone and valproic acid;

[0375] Carbonate solvents such as diethyl carbonate, ethylene carbonate, and propylene carbonate;

[0376] Solvents such as propylene glycol diacetate, methoxytriethylene glycol acetate, diethyl oxalate, ethyl acetoacetate, and diethyl phthalate are polycarboxylic acid diesters.

[0377] Examples of hydrocarbon solvents include:

[0378] Aliphatic hydrocarbon solvents such as n-hexane, cyclohexane, and methylcyclohexane;

[0379] Aromatic hydrocarbon solvents such as benzene, toluene, diisopropylbenzene, and n-pentylnaphthalene.

[0380] Among these, ester-based solvents, ether-based solvents, and alcohol-based solvents are preferred; more preferably, polyol partial ether acetate-based solvents, lactone-based solvents, monocarboxylic acid ester-based solvents, ketone-based solvents, alcohol ester-based solvents, and monohydric alcohol-based solvents are preferred; even more preferably, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, γ-butyrolactone, ethyl lactate, cyclohexanone, propylene glycol monomethyl ether, isopropyl 2-hydroxyisobutyrate, and diacetone alcohol are preferred. The radiosensitive composition may contain one or more solvents.

[0381] (Any other ingredients)

[0382] The radiosensitive linear composition may contain any other components besides the aforementioned ingredients. Examples of such other components include: crosslinking agents, pre-existing accelerators, surfactants, compounds containing alicyclic skeletons, sensitizers, etc. One or more of these other components may be used individually or in combination.

[0383] There are no particular limitations on the surfactant used, but non-fluorinated surfactants or non-silicone surfactants are preferred.

[0384] When the radiosensitive linear composition contains a surfactant, the surfactant content is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, relative to 100 parts by mass of the base polymer (A). Furthermore, it is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less.

[0385] <Preparation Method of Radiosensitive Linear Composition>

[0386] The radiosensitive linear composition can be prepared, for example, by mixing a polymer (A), a radiosensitive linear acid generator (B), a solvent (E), and other radiosensitive linear acid generators, acid diffusion control agents (D), high-fluorine polymers, etc., as needed, in a prescribed ratio. The radiosensitive linear composition is preferably filtered after mixing, for example, using a filter with a pore size of approximately 0.05 μm to 0.40 μm. The concentration of the solid component in the radiosensitive linear composition is typically 0.1% to 50% by mass, preferably 0.5% to 30% by mass, and more preferably 1% to 20% by mass.

[0387] <Pattern Formation Method>

[0388] A pattern forming method according to one embodiment of the present invention includes:

[0389] The process (1) of directly or indirectly coating the radiosensitive linear composition onto a substrate to form a resist film (hereinafter also referred to as the "resist film formation process").

[0390] The process of exposing the resist film (2) (hereinafter also referred to as the "exposure process"); and

[0391] The process of developing the exposed resist film (3) (hereinafter also referred to as the “development process”).

[0392] According to the resist patterning method described above, since the photosensitive linear composition is used to form a resist film with excellent sensitivity, LWR, MEEF, CDU, development defect performance, pattern rectangularity, and pattern circularity in the exposure process, high-quality resist patterns can be formed. The following describes each step.

[0393] [Resist film formation process]

[0394] In this process (process (1)), a photoresist film is formed using the aforementioned photosensitive linear composition. Examples of substrates for forming the photoresist film include, for example, silicon wafers, silicon dioxide, aluminum-clad wafers, and other existing materials. Alternatively, organic or inorganic antireflective films disclosed in, for example, Japanese Patent Application Publication No. 6-12452 or Japanese Patent Application Publication No. 59-93448 may be formed on the substrate. Examples of coating methods include, for example, spin coating, cast coating, and roll coating. After coating, a pre-bake (PB) may be performed as needed to allow the solvent in the coating to evaporate. The PB temperature is typically 60°C to 150°C, preferably 80°C to 140°C. The PB time is typically 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds.

[0395] The lower limit of the thickness of the formed resist film is preferably 10 nm, more preferably 15 nm, and even more preferably 20 nm. The upper limit of the film thickness is preferably 500 nm, more preferably 400 nm, and even more preferably 300 nm. For thick resist films, when exposure using ArF excimer laser light is performed in the exposure process described later, the lower limit of the film thickness may be 100 nm, 150 nm, or 200 nm.

[0396] In the case of immersion exposure, regardless of the presence or absence of water-repellent polymer additives such as the high-fluorine-content polymer in the radiosensitive linear composition, a immersion protective film that is 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 immersion protective film, either a solvent-removable protective film that is peeled off with a solvent before the developing process (e.g., see Japanese Patent Application Publication No. 2006-227632) or a developer-removable protective film that is peeled off simultaneously with the developing process (e.g., see International Publication No. 2005 / 069076 and International Publication No. 2006 / 035790) may be used. From the viewpoint of yield, a developer-removable immersion protective film is preferred.

[0397] Furthermore, when using radiation with a wavelength of 50 nm or less for the exposure process as the next step, it is preferable to use a polymer having the aforementioned structural unit (I) and structural unit (IV) as the base polymer in the composition.

[0398] [Exposure Process]

[0399] In this step (step (2)), a photomask (which may be a liquid immersion medium such as water) exposes the resist film formed in step (1), i.e., the resist film formation step, to radiation. The radiation used for exposure can be, for example, electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light (EUV), X-rays, and gamma rays, depending on the linewidth of the target pattern; or charged particle beams such as electron beams and alpha rays. Among these, far ultraviolet light, electron beams, and EUV are preferred, and ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), electron beams, and EUV are more preferred. Furthermore, electron beams and EUV with wavelengths of 50 nm or less, which are positioned as next-generation exposure technologies, are even more preferred.

[0400] When exposure is performed by immersion exposure, the immersion liquid used can be, for example, water or a fluorine-based inactive liquid. The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has a temperature coefficient of refractive index that is as small as possible to minimize distortion of the optical image projected onto the film. Especially when the exposure light source is an ArF excimer laser (wavelength 193 nm), water is preferred in terms of ease of acquisition and ease of operation. When using water, additives that reduce the surface tension of water and increase interfacial activity can be added in small proportions. These additives are preferably those that do not dissolve the resist film on the wafer and whose effect on the optical coating on the lower surface of the lens is negligible. Distilled water is preferred as the water used.

[0401] Preferably, a post-exposure bake (PEB) is performed after the initial exposure. In the exposed portions of the resist film, the acid generated by the radiosensitive linear acid generator during exposure promotes the dissociation of acid-dissociative groups in the polymer or the like. This PEB creates a difference in solubility of the developer between the exposed and unexposed portions. The PEB temperature is typically 50°C to 180°C, preferably 80°C to 130°C. The PEB time is typically 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds.

[0402] [Developing process]

[0403] In this step (step (3)), the resist film exposed in step (2), i.e., the exposure step, is developed. Thus, a specified resist pattern can be formed. Generally, after development, the film is rinsed with a solution such as water or alcohol and then dried.

[0404] As the developing solution used in the aforementioned development, in the case of alkaline development, examples include alkaline aqueous solutions containing at least one of the following alkaline compounds: sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyl diethylamine, ethyl dimethylamine, triethanolamine, tetramethyl ammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, and 1,5-diazabicyclo-[4.3.0]-5-nonene. Among these, an aqueous solution of TMAH is preferred, and a 2.38% by mass aqueous solution of TMAH is more preferred.

[0405] In addition, when developing with an organic solvent, examples of organic solvents include hydrocarbon-based solvents, ether-based solvents, ester-based solvents, ketone-based solvents, alcohol-based solvents, and solvents containing organic solvents. Examples of such organic solvents include one or more solvents listed as solvents for the radiosensitive linear composition. Among these, ether-based solvents, ester-based solvents, and ketone-based solvents are preferred. As an ether-based solvent, glycol ether-based solvents are preferred, more preferably ethylene glycol monomethyl ether or propylene glycol monomethyl ether. As an ester-based solvent, acetate-based solvents are preferred, more preferably n-butyl acetate or amyl acetate. As a ketone-based solvent, chain ketones are preferred, more preferably 2-heptanone. The content of organic solvent in the developing solution is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, particularly preferably 99% by mass or more. Other components in the developing solution besides the organic solvent include, for example, water and silicone oil.

[0406] As mentioned above, the developer can be any type of alkaline developer or organic solvent developer. The appropriate developer can be selected depending on whether the target pattern is positive or negative.

[0407] Examples of development methods include: immersing a substrate in a tank filled with developer for a fixed time (immersion method); developing a substrate by using surface tension to accumulate developer on the substrate surface and then allowing it to stand still for a fixed time (puddle method); spraying developer onto the substrate surface (spraying method); and continuously spraying developer onto a substrate rotating at a fixed speed while scanning the developer nozzle at a fixed speed (dynamic distribution method), etc.

[0408] Radiosensitive linear acid generator

[0409] The radiosensitive linear acid generator of this embodiment is represented by the following formula (1).

[0410] [Transformation 50]

[0411]

[0412] (In the above formula (1),

[0413] R 1 It can be a hydrogen atom, nitro group, hydroxyl group, cyano group, carboxyl group, thiol group, halogen atom, or monovalent organic group; in R 1 In the case of multiple Rs, multiple Rs 1 They are the same or different;

[0414] R 2 It is a monovalent organic group with 1 to 40 carbon atoms;

[0415] m is an integer from 1 to 5;

[0416] M + (It is a monovalent onium cation)

[0417] As the radiosensitive linear acid generator represented by the formula (1), the radiosensitive linear acid generator (B) in the radiosensitive linear composition can preferably be used.

[0418] Example

[0419] The present invention will now be described in detail based on embodiments, but the present invention is not limited to these embodiments. Methods for determining various physical properties are shown below.

[0420] [Weight-average molecular weight (Mw) and number-average molecular weight (Mn)]

[0421] The Mw and Mn of the polymer were determined under the conditions described above. Furthermore, the dispersity (Mw / Mn) was calculated based on the results of the Mw and Mn measurements.

[0422] [ 13 C-NMR ( 13 C-Nuclear Magnetic Resonance, 13 [C-NMR analysis]

[0423] polymers 13 C-NMR analysis was performed using a nuclear magnetic resonance apparatus (JNM-Delta400 of Nippon Electron Ltd).

[0424] <Polymer Synthesis>

[0425] The following shows the monomers used in the synthesis of each polymer in each embodiment and comparative example. Furthermore, in the following synthesis examples, unless otherwise specified, parts by mass refer to the value when the total mass of the monomers used is set to 100 parts by mass, and mol% refers to the value when the total number of moles of the monomers used is set to 100 mol%.

[0426] [Chemistry 51]

[0427]

[0428] [Synthesis example 1]

[0429] (Synthesis of polymer (A-1))

[0430] Monomers (M-1), (M-2), (M-5), (M-10), and (M-14) were dissolved in 200 parts by mass of 2-butanone in a molar ratio of 40 / 10 / 20 / 20 / 10 (mol%). Azobisisobutyronitrile (AIBN) (5 mol% relative to the total 100 mol% of the monomers used) was added as an initiator to prepare a monomer solution. 100 parts by mass of 2-butanone were placed in a reaction vessel, purged with nitrogen for 30 minutes, and the reaction vessel was set to 80°C. The monomer solution was added dropwise over 3 hours with 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. After the polymerization reaction was completed, the polymerization solution was water-cooled to below 30°C. The cooled polymerization solution was then 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, then filtered again, and dried at 50°C for 24 hours to obtain a white powdery polymer (A-1) (yield: 85%). The polymer (A-1) had a Mw of 7,100 and an Mw / Mn ratio of 1.61. Additionally, 13 The results of C-NMR analysis showed that the proportions of each structural unit derived from (M-1), (M-2), (M-5), (M-10) and (M-14) were 40.3 mol%, 9.2 mol%, 20.5 mol%, 19.8 mol%, and 10.2 mol%, respectively.

[0431] [Synthesis Examples 2 to 11]

[0432] (Synthesis of polymers (A-2) to (A-11))

[0433] Polymers (A-2) to (A-11) were synthesized in the same manner as in Synthesis Example 1, except that the monomers of the types and proportions shown in Table 1 below were used. The content proportions (mol%) and physical properties (Mw and Mw / Mn) of each structural unit of the obtained polymers are shown in Table 1 below. In addition, "-" in Table 1 below indicates that the corresponding monomer was not used (the same applies to subsequent tables).

[0434] [Table 1]

[0435]

[0436] (Synthesis of polymer (A-12))

[0437] Monomers (M-1) and (M-18) were dissolved in 1-methoxy-2-propanol (200 parts by mass) at a molar ratio of 50 / 50 (mol%), and AIBN (5 mol%) was added as an initiator to prepare a monomer solution. 1-methoxy-2-propanol (100 parts by mass) was placed in a reaction vessel, purged with nitrogen for 30 minutes, and the reaction vessel was set to 80°C. The monomer solution was added dropwise over 3 hours with 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. After the polymerization reaction was completed, the polymerization solution was water-cooled to below 30°C. The cooled polymerization solution was added to hexane (2,000 parts by mass), and the precipitated white powder was filtered and separated. The filtered white powder was washed twice with hexane, filtered again, and dissolved in 1-methoxy-2-propanol (300 parts by mass). Subsequently, methanol (500 parts by mass), triethylamine (50 parts by mass), and ultrapure water (10 parts by mass) were added, and a hydrolysis reaction was carried out at 70°C for 6 hours with stirring. After the reaction was completed, 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 polymer. The obtained solid was separated by filtration and dried at 50°C for 13 hours to obtain a white powder polymer (A-12) (yield: 81%). The Mw of polymer (A-12) was 5,500, and the Mw / Mn ratio was 1.62. Additionally, 13 The results of C-NMR analysis showed that the proportions of each structural unit derived from (M-1) and (M-18) were 50.2 mol% and 49.8 mol%, respectively.

[0438] [Synthesis Examples 13 to 15]

[0439] (Synthesis of polymers (A-13) to (A-15))

[0440] Using the monomers of the types and proportions shown in Table 2 below, polymers (A-13) to (A-15) were synthesized in the same manner as in Synthesis Example 12, except that... Furthermore, regarding the monomers providing structural units (IV), in the polymers, by... 13 C-NMR measurements confirmed the disappearance of the carbonyl peak of the acetyl group, indicating that all the base-dissociated groups were essentially hydrolyzed to become phenolic hydroxyl groups. The content ratio (mol%) and physical property values ​​(Mw and Mw / Mn) of each structural unit of the obtained polymer are shown in Table 2 below.

[0441] [Table 2]

[0442]

[0443] [Synthesis Example 16]

[0444] (Synthesis of high-fluorine polymer (F-1))

[0445] Monomers (M-1) and (M-20) were dissolved in 200 parts by mass of 2-butanone at a molar ratio of 20 / 80 (mol%), and AIBN (4 mol%) was added as an initiator to prepare a monomer solution. 100 parts by mass of 2-butanone was placed in a reaction vessel, purged with nitrogen for 30 minutes, and the reaction vessel was set to 80°C. 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. After the polymerization reaction was completed, the polymerization solution was water-cooled to below 30°C. After replacing the solvent with acetonitrile (400 parts by mass), hexane (100 parts by mass) was added, 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 the high-fluorine polymer (F-1) was obtained (yield: 75%). The high-fluorine polymer (F-1) has a Mw of 6,200 and an Mw / Mn ratio of 1.77. Additionally, 13 The results of C-NMR analysis showed that the proportions of each structural unit derived from (M-1) and (M-20) were 19.5 mol% and 80.5 mol%, respectively.

[0446] [Synthesis Examples 17 to 20]

[0447] (Synthesis of high-fluorine polymers (F-2) to high-fluorine polymers (F-5))

[0448] Using the monomers of the types and proportions shown in Table 3 below, high-fluorine polymers (F-2) to (F-5) were synthesized in the same manner as in Synthesis Example 16. The content (mol%) and physical property values ​​(Mw and Mw / Mn) of each structural unit of the obtained high-fluorine polymers are shown in Table 3 below.

[0449] [Table 3]

[0450]

[0451] <Synthesis of radiosensitive linear acid generator (B)>

[0452] [Example B1]

[0453] (Synthesis of compound (B-1))

[0454] The following synthetic procedure was followed to synthesize compound (B-1).

[0455] [Chemistry 52]

[0456]

[0457] In a reaction vessel, 20.0 mmol of n-propyl bromoacetate, 25.0 mmol of potassium tert-butoxy, 25.0 mmol of difluoromethylphenyl sulfone, and 100 g of dimethylformamide were added, and the mixture was stirred at -20°C for 1 hour. Afterward, the reaction was stopped by adding a saturated aqueous ammonium chloride solution, followed by extraction with ethyl acetate, and the organic layer was separated. The obtained organic layer was washed successively with a saturated aqueous sodium chloride solution and water. After drying with sodium sulfate, the solvent was removed by distillation, and the mixture was purified by column chromatography to obtain sulfones in good yield.

[0458] 100 mmol of disodium hydrogen phosphate, 100 mmol of Na / Hg amalgam, and 50 g of methanol were added to the sulfone, and the mixture was stirred at room temperature for 1 hour. The solid components in the reaction solution were then removed by diatomaceous earth filtration. The solvent in the obtained filtrate was removed by distillation, and the solution was purified by column chromatography to obtain the difluoride in good yield.

[0459] 25.0 mmol of sodium hydride, 25.0 mmol of bromine, and 50 g of tetrahydrofuran were added to the difluorinated compound, and the mixture was stirred at room temperature for 1 hour. Afterward, the reaction was stopped by adding a saturated aqueous solution of ammonium chloride, followed by extraction with ethyl acetate, and the organic layer was separated. The obtained organic layer was washed successively with a saturated aqueous solution of sodium chloride and water. After drying with sodium sulfate, the solvent was removed by distillation, and the mixture was purified by column chromatography, thereby obtaining the bromine compound in good yield.

[0460] A 1 M solution was prepared by adding an acetonitrile:water mixture (1:1 mass ratio) to the bromide gas, followed by the addition of 40.0 mmol of sodium dithionite and 60.0 mmol of sodium bicarbonate, and reacted at 70°C for 4 hours. After extraction with acetonitrile and distillation to remove the solvent, a 0.5 M solution was prepared by adding an acetonitrile:water mixture (3:1 mass ratio). 60.0 mmol of hydrogen peroxide solution and 2.00 mmol of sodium tungstate were added, and the mixture was heated and stirred at 50°C for 12 hours. After extraction with acetonitrile and distillation to remove the solvent, a sodium sulfonate compound was obtained. 20.0 mmol of triphenylsulfonium bromide was added to the sodium sulfonate compound, along with a 1:3 mass ratio of water and dichloromethane, to prepare a 0.5 M solution. After vigorous stirring at room temperature for 3 hours, extraction with dichloromethane was performed, and the organic layer was separated. After drying the obtained organic layer with sodium sulfate, the solvent was removed by distillation and purified by column chromatography, thereby obtaining the onium salt compound represented by formula (B-1) (compound (B-1)) in good yield.

[0461] [Examples B2-B10]

[0462] (Synthesis of compounds (B-2) to (B-10))

[0463] With appropriate changes to the raw materials and precursors, the onium salt compounds represented by the following formulas (B-2) to (B-10) are synthesized in the same manner as in Example B1.

[0464] [Chemistry 53]

[0465]

[0466] [Examples B11, B12]

[0467] (Synthesis of compounds (B-11) and (B-12))

[0468] Compounds (B-11) and (B-12) were synthesized according to the following synthetic procedure.

[0469] [Chemistry 54]

[0470]

[0471] In a reaction vessel, 20.0 mmol of an olefin compound, 25.0 mmol of sodium bisulfite, 2.00 mmol of AIBN, 50 g of water, and 50 g of methanol were added, and the mixture was stirred at 85°C for 10 hours. The solvent was then removed by distillation to obtain a crude sodium sulfonate compound. 20.0 mmol of triphenylsulfonium bromide was added to the sodium sulfonate compound, along with a mixture of water and dichloromethane (1:3 by mass) to prepare a 0.5 M solution. After vigorous stirring at room temperature for 3 hours, dichloromethane was added for extraction, and the organic layer was separated. The obtained organic layer was dried with sodium sulfate, the solvent was removed by distillation, and the solution was purified by column chromatography to obtain the onium salt compound represented by formula (B-11) (compound (B-11)) in good yield.

[0472] Compound (B-11) was reacted with 25.0 mmol of cyclopentyl carboxylate, 25.0 mmol of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 5.0 mmol of 4-dimethylaminopyridine, and 50 g of dichloromethane at room temperature for 12 hours. The reaction was then stopped by adding 1 M aqueous hydrochloric acid, followed by extraction with dichloromethane and separation of the organic layer. After drying with sodium sulfate, the solvent was removed by distillation, and the mixture was purified by column chromatography to obtain the onium salt compound (B-12) in good yield.

[0473] [Examples B13-B18]

[0474] (Synthesis of compounds (B-13) to (B-18))

[0475] With appropriate changes to the raw materials and precursors, the onium salt compounds represented by the following formulas (B-13) to (B-18) (compounds (B-13) to (B-18)) can be synthesized in the same manner as in Examples B11 and B12.

[0476] [Chemistry 55]

[0477]

[0478] [Example B19]

[0479] (Synthesis of compound (B-19))

[0480] The following synthetic procedure was followed to synthesize compound (B-19).

[0481] [Chemistry 56]

[0482]

[0483] 20.0 mmol of 1,1-difluoroacetone, 20.0 mmol of phenylmagnesium bromide, and 50 g of tetrahydrofuran were added to a reaction vessel and stirred at room temperature for 1 hour. The reaction was then stopped by adding a saturated aqueous ammonium chloride solution, followed by extraction with ethyl acetate, and the organic layer was separated. The obtained organic layer was washed successively with a saturated aqueous sodium chloride solution and water. After drying with sodium sulfate, the solvent was removed by distillation, and the mixture was purified by column chromatography to obtain the alcohol in good yield.

[0484] 25.0 mmol of phosphorus tribromide and 50 g of toluene were added to the alcohol, and the reaction was carried out at 100 °C for 12 hours. Afterward, water was added to stop the reaction, followed by extraction with dichloromethane, and the organic layer was separated. The obtained organic layer was washed successively with saturated sodium chloride aqueous solution and water. After drying with sodium sulfate, the solvent was removed by distillation, and the solution was purified by column chromatography, thereby obtaining the bromide in good yield.

[0485] A 1 M solution was prepared by adding an acetonitrile:water mixture (1:1 mass ratio) to the bromide gas, followed by the addition of 40.0 mmol of sodium dithionite and 60.0 mmol of sodium bicarbonate, and reacted at 70°C for 4 hours. After extraction with acetonitrile and distillation to remove the solvent, a 0.5 M solution was prepared by adding an acetonitrile:water mixture (3:1 mass ratio). 60.0 mmol of hydrogen peroxide solution and 2.00 mmol of sodium tungstate were added, and the mixture was heated and stirred at 50°C for 12 hours. After extraction with acetonitrile and distillation to remove the solvent, a sodium sulfonate compound was obtained. 20.0 mmol of triphenylsulfonium bromide was added to the sodium sulfonate compound, along with a 1:3 mass ratio of water and dichloromethane, to prepare a 0.5 M solution. After vigorous stirring at room temperature for 3 hours, extraction with dichloromethane was performed, and the organic layer was separated. After drying the obtained organic layer with sodium sulfate, the solvent was removed by distillation and purified by column chromatography, thereby obtaining the onium salt compound (compound (B-19)) represented by the formula (B-19) in good yield.

[0486] [Examples B20, B21]

[0487] (Synthesis of compounds (B-20) to (B-21))

[0488] With appropriate changes to the raw materials and precursors, the onium salt compounds represented by the following formulas (B-20) to (B-21) (compounds (B-20) to (B-21)) are synthesized in the same manner as in Example B19.

[0489] [Chemistry 57]

[0490]

[0491] [Example B22]

[0492] (Synthesis of compound (B-22))

[0493] The following synthetic procedure was followed to synthesize compound (B-22).

[0494] [Chem.58]

[0495]

[0496] In a reaction vessel, 20.0 mmol of 1,1-difluoroacetone, 25.0 mmol of α-bromo-γ-butyrolactone, 30.0 mmol of zinc, 5.00 mmol of trimethylsilyl chloride, and 50 g of tetrahydrofuran were added, and the mixture was stirred at room temperature for 1 hour. Afterward, the reaction was stopped by adding a saturated aqueous ammonium chloride solution, followed by extraction with ethyl acetate, and the organic layer was separated. The obtained organic layer was washed successively with a saturated aqueous sodium chloride solution and water. After drying with sodium sulfate, the solvent was removed by distillation, and the mixture was purified by column chromatography to obtain the alcohol in good yield.

[0497] 25.0 mmol of phosphorus tribromide and 50 g of toluene were added to the alcohol, and the reaction was carried out at 100 °C for 12 hours. Afterward, water was added to stop the reaction, followed by extraction with dichloromethane, and the organic layer was separated. The obtained organic layer was washed successively with saturated sodium chloride aqueous solution and water. After drying with sodium sulfate, the solvent was removed by distillation, and the solution was purified by column chromatography, thereby obtaining the bromide in good yield.

[0498] A 1 M solution was prepared by adding an acetonitrile:water mixture (1:1 mass ratio) to the bromide gas, followed by the addition of 40.0 mmol of sodium dithionite and 60.0 mmol of sodium bicarbonate, and reacted at 70°C for 4 hours. After extraction with acetonitrile and distillation to remove the solvent, a 0.5 M solution was prepared by adding an acetonitrile:water mixture (3:1 mass ratio). 60.0 mmol of hydrogen peroxide solution and 2.00 mmol of sodium tungstate were added, and the mixture was heated and stirred at 50°C for 12 hours. After extraction with acetonitrile and distillation to remove the solvent, a sodium sulfonate compound was obtained. 20.0 mmol of triphenylsulfonium bromide was added to the sodium sulfonate compound, along with a 1:3 mass ratio of water and dichloromethane, to prepare a 0.5 M solution. After vigorous stirring at room temperature for 3 hours, extraction with dichloromethane was performed, and the organic layer was separated. After drying the obtained organic layer with sodium sulfate, the solvent was removed by distillation and purified by column chromatography, thereby obtaining the onium salt compound (compound (B-22)) represented by formula (B-22) in good yield.

[0499] [Examples B23-B24]

[0500] (Synthesis of compounds (B-23) to (B-24))

[0501] With appropriate changes to the raw materials and precursors, the onium salt compounds represented by the following formulas (B-23) to (B-24) (compounds (B-23) to (B-24)) are synthesized in the same manner as in Example B22.

[0502] [Chemistry 59]

[0503]

[0504] [Example B25]

[0505] (Synthesis of compound (B-25))

[0506] The following synthetic procedure was followed to synthesize compound (B-25).

[0507] [Transformation 60]

[0508]

[0509] 20.0 mmol of ethyl 4,4-difluoroacetoacetate, 25.0 mmol of sodium bisulfite, 25 g of water, and 50 g of methanol were added to a reaction vessel and stirred at room temperature for 4 hours. Then, 30.0 mmol of triphenylsulfonium bromide, 25 g of water, and 50 g of dichloromethane were added, and the mixture was stirred at room temperature for 4 hours. After dilution with water, dichloromethane was added for extraction, and the organic layer was separated. The obtained organic layer was dried with sodium sulfate, and the solvent was removed by distillation to obtain compound (B-25-1) in good yield.

[0510] Compound (B-25-1) was reacted with 25.0 mmol of adamantane carboxyl chloride, 25.0 mmol of pyridine, and 50 g of dichloromethane at 40 °C for 12 hours. The reaction was then stopped by adding a saturated aqueous ammonium chloride solution, followed by extraction with dichloromethane and separation of the organic layer. The obtained organic layer was washed successively with a saturated aqueous sodium chloride solution and water. After drying with sodium sulfate, the solvent was removed by distillation, and the mixture was purified by column chromatography, thereby obtaining the onium salt compound (compound (B-25)) represented by formula (B-25) in good yield.

[0511] [Examples B26-B27]

[0512] (Synthesis of compounds (B-26) to (B-27))

[0513] With appropriate changes to the raw materials and precursors, the onium salt compounds represented by the following formulas (B-26) to (B-27) (compounds (B-26) to (B-27)) are synthesized in the same manner as in Example B25.

[0514] [Chemistry 61]

[0515]

[0516] The following compounds are used as components other than those used in the synthesis.

[0517] [Radiosensitive linear acid generators other than (B-1) to (B-27)]

[0518] b-1~b-12: The compounds represented by the following formulas (b-1)~(b-12) (hereinafter, the compounds represented by formulas (b-1)~(b-12) are sometimes referred to as "compound (b-1)"~"compound (b-12)" respectively)

[0519] [Chemistry 62]

[0520]

[0521] [Acid diffusion control agent (D)]

[0522] D-1 to D-7: The compounds represented by the following formulas (D-1) to (D-7).

[0523] [Chemistry 63]

[0524]

[0525] [Solvent (E)]

[0526] E-1: Propylene glycol monomethyl ether

[0527] E-2: Propylene glycol monomethyl ether

[0528] E-3: γ-Butyrolactone

[0529] E-4: Ethyl lactate

[0530] E-5: Isopropyl 2-hydroxyisobutyrate

[0531] E-6: Diacetone alcohol

[0532] [[W] Other additive ingredients]

[0533] W-1: MEGAFACE EFS-321 (manufactured by DIC) (non-fluorine based)

[0534] W-2: BYK-399 (manufactured by BYK Chemical Co., Ltd., Japan) (non-silicon based)

[0535] [Preparation of positive-type radiosensitive linear compositions for ArF immersion exposure]

[0536] [Example 1]

[0537] A mixture of 100 parts by mass of (A-1) as polymer (A), 10.0 parts by mass of (B-1) as radiosensitive linear acid generator (B), 4.0 parts by mass of (D-1) as acid diffusion control agent (D), 5.0 parts by mass of (F-1) as high fluorine content polymer (F) (solid component), and 3,400 parts by mass of a mixed solvent of (E-1) / (E-2) / (E-3) as solvent (E) was prepared by filtering the mixture using a membrane filter with a pore size of 0.2 μm.

[0538] [Examples 2-50, 101-109 and Comparative Examples 1-3]

[0539] Using the types and amounts of each component shown in Tables 4-1 and 4-2 below, except that, the radiosensitive linear compositions (J-2) to (J-50), (J-101) to (J-109) and (CJ-1) to (CJ-3) were prepared in the same manner as in Example 1.

[0540] [Table 4-1]

[0541]

[0542] [Table 4-2]

[0543]

[0544] <Formation of resist patterns using ArF immersion exposure with positive-type radiosensitive linear compositions>

[0545] Using a spin coater (Tokyo Electron Inc.'s "CLEAN TRACK ACT12"), a lower antireflective film forming composition (Brewer Science's "ARC66") was applied onto a 12-inch silicon wafer, followed by heating at 205°C for 60 seconds to form a lower antireflective film with an average thickness of 100 nm. The prepared ArF exposure positive-type radiosensitive linear composition was then applied onto the lower antireflective film using the same spin coater and pre-baked at 100°C for 60 seconds (PB). Afterward, it was cooled at 23°C for 30 seconds to form a resist film with an average thickness of 100 nm. Next, the resist film was exposed using an ArF excimer laser immersion exposure system (ASML's "TWINSCAN XT-1900i") with optical conditions of NA=1.35 and dipole (σ=0.9 / 0.7) to a mask pattern separating 60 nm lines and space. After exposure, it was baked (PEB) at 100°C for 60 seconds. Subsequently, the resist film was alkaline developed using a 2.38% by mass tetramethylammonium hydroxide (TMAH) aqueous solution as an alkaline developer. After development, it was rinsed with water and then dried, thereby forming a positive resist pattern (55 nm line and space pattern).

[0546] <Evaluation>

[0547] For the resist patterns formed using the aforementioned ArF immersion exposure positive-type radiometric linear composition, the sensitivity, LWR, pattern rectangularity, and number of development defects were evaluated according to the following methods. The results are shown in Tables 5-1 and 5-2 below. Furthermore, the length of the resist patterns was measured using a scanning electron microscope (Hitachi High-Technologies, Inc.'s "CG-5000").

[0548] [sensitivity]

[0549] In the formation of the resist pattern using the aforementioned ArF immersion exposure positive-type radiosensitive linear composition, the exposure amount for forming the 55 nm line and spatial pattern is set as the optimal exposure amount, and the optimal exposure amount is set as the sensitivity (mJ / cm). 2 Regarding sensitivity, 15 mJ / cm 2 Above and 30 mJ / cm 2 The following conditions are rated as "good", and those below 15 mJ / cm 2 or more than 30 mJ / cm 2 The situation was rated as "poor".

[0550] [LWR]

[0551] A 55 nm line-space resist pattern was formed by irradiation with the optimal exposure determined from the aforementioned sensitivity evaluation. The formed resist pattern was observed from the top of the pattern using the aforementioned scanning electron microscope. The linewidth deviation at a total of 500 points was measured, and a 3-sigma value was determined based on the distribution of the measured values. This 3-sigma value was set as LWR (nm). The smaller the LWR value, the lower the line roughness and the better. Regarding LWR, cases below 3.0 nm were evaluated as "good," and cases above 3.0 nm were evaluated as "poor."

[0552] [Pattern Rectangularity]

[0553] For the 55 nm line-space resist pattern formed by irradiation with the optimal exposure determined in the sensitivity evaluation, the cross-sectional shape of the line-space pattern is evaluated using the scanning electron microscope. Regarding the rectangularity of the resist pattern, if the ratio of the length of the lower side to the length of the upper side in the cross-sectional shape is greater than or equal to 1.00 and less than 1.05, it is rated "A" (extremely good); if it is greater than 1.05 and less than 1.10, it is rated "B" (good); and if it is greater than 1.10, it is rated "C" (poor).

[0554] [Number of developmental defects]

[0555] A line and space pattern with a linewidth of 55 nm was formed by exposing the resist film at the optimal exposure level, and this was designated as a defect inspection wafer. The number of defects on the defect inspection wafer was measured using a defect inspection device (KLA-Tencor's "KLA2810"). Defects with a diameter of 50 μm or less were identified as originating from the resist film, and their number was calculated. Regarding the number of defects after development, cases where the number of defects identified as originating from the resist film was 50 or less were evaluated as "good," and cases where the number exceeded 50 were evaluated as "bad."

[0556] [Table 5-1]

[0557]

[0558] [Table 5-2]

[0559]

[0560] Based on the results in Tables 5-1 and 5-2, it is clear that the radiosensitive linear composition of the examples exhibits good sensitivity, LWR, pattern rectangularity, and number of development defects when used for ArF immersion exposure. In contrast, the comparative examples show inferior characteristics compared to the examples. Therefore, when the radiosensitive linear composition of the examples is used for ArF immersion exposure, the sensitivity is optimal, and a resist pattern with good LWR, pattern rectangularity, and number of development defects can be formed.

[0561] [Preparation of ArF-Dry Exposure Positive Radiation-Inducing Linear Composition]

[0562] [Example 51]

[0563] 100 parts by mass of (A-1) as polymer (A), 6.0 parts by mass of (B-1) as radiosensitive linear acid generator (B), 3.0 parts by mass of (D-2) as acid diffusion control agent (D), and 3,230 parts by mass of a mixed solvent of (E-1) / (E-2) / (E-3) as solvent (E) were mixed and filtered using a membrane filter with a pore size of 0.2 μm to prepare a radiosensitive linear composition (J-51).

[0564] [Examples 52-66 and Comparative Examples 4-6]

[0565] Using the types and amounts of each component shown in Table 6 below, except that, the radiosensitive linear compositions (J-52) to (J-66) and (CJ-4) to (CJ-6) were prepared in the same manner as in Example 51.

[0566] [Table 6]

[0567]

[0568] <Formation of resist patterns using ArF-dry exposure positive-type radiosensitive linear composition>

[0569] Using a spin coater (Tokyo Electron Inc.'s "CLEAN TRACK ACT8"), a lower antireflective film forming composition (Brewer Science's "ARC29") was applied onto an 8-inch silicon wafer, followed by heating at 205°C for 60 seconds to form a lower antireflective film with an average thickness of 70 nm. The prepared ArF-dry exposure positive radiometric linear composition was then applied onto the lower antireflective film using the same spin coater and pre-baked at 100°C for 60 seconds (PB). Afterward, it was cooled at 23°C for 30 seconds to form a resist film with an average thickness of 210 nm. Next, the resist film was exposed using an ArF excimer laser (Nikon S306C) with optical conditions of NA=0.75 and annular (σ=0.8 / 0.6) to form a resist pattern with a linewidth of 90 nm. After exposure, it was baked (PEB) at 100°C for 60 seconds. Then, the resist film was alkaline developed using a 2.38% by mass TMAH aqueous solution as an alkaline developer. After development, it was rinsed with water and then dried, thereby forming a positive resist pattern (a resist pattern with a linewidth of 90 nm).

[0570] <Evaluation>

[0571] For the resist pattern formed using the ArF-dry exposure positive-type radiometric linear composition described above, the sensitivity, LWR, pattern rectangularity, and number of development defects were evaluated according to the following method. The results are shown in Table 7 below. In addition, the length of the resist pattern was measured using a scanning electron microscope (Hitachi High-Technologies, Inc.'s "S-9380").

[0572] [sensitivity]

[0573] In the formation of the resist pattern using the ArF-dry exposure positive-type radiosensitive linear composition, the exposure amount for forming the 90 nm line and spatial pattern is set as the optimal exposure amount, and the optimal exposure amount is set as the sensitivity (mJ / cm). 2 Regarding sensitivity, 25 mJ / cm 2 Above and 40 mJ / cm 2 The following conditions are rated as "good", and those below 25 mJ / cm 2 or more than 40 mJ / cm 2 The situation was rated as "poor".

[0574] [LWR]

[0575] A 90 nm line-space resist pattern was formed by irradiation with the optimal exposure determined from the aforementioned sensitivity evaluation. The formed resist pattern was observed from the top of the pattern using the aforementioned scanning electron microscope. The linewidth deviation at a total of 500 points was measured, and a 3-sigma value was determined based on the distribution of the measured values. This 3-sigma value was set as LWR (nm). The smaller the LWR value, the lower the line roughness and the better. Regarding LWR, cases below 4.0 nm were evaluated as "good," and cases above 4.0 nm were evaluated as "poor."

[0576] [Pattern Rectangularity]

[0577] For the 90 nm line-space resist pattern formed by irradiation with the optimal exposure determined in the sensitivity evaluation, the cross-sectional shape of the line-space pattern is evaluated using the scanning electron microscope. Regarding the rectangularity of the resist pattern, if the ratio of the length of the lower side to the length of the upper side in the cross-sectional shape is greater than or equal to 1.00 and less than 1.05, it is rated "A" (extremely good); if it is greater than 1.05 and less than 1.10, it is rated "B" (good); and if it is greater than 1.10, it is rated "C" (poor).

[0578] [Number of developmental defects]

[0579] A line and space pattern with a linewidth of 90 nm is formed by exposing the resist film at the optimal exposure level, and this is designated as a defect inspection wafer. The number of defects on the defect inspection wafer is measured using a defect inspection device (KLA-Tencor's "KLA2810"). Defects with a diameter of 50 μm or less are identified as originating from the resist film, and their number is calculated. Regarding the number of defects after development, cases where the number of defects identified as originating from the resist film is 50 or less are evaluated as "good," and cases where the number exceeds 50 are evaluated as "bad."

[0580] [Table 7]

[0581]

[0582] Based on the results in Table 7, it is clear that the linearly oriented resist composition of the Examples exhibits good sensitivity, LWR, pattern rectangularity, and number of development defects when used for ArF-dry exposure. In contrast, the Comparative Examples show inferior characteristics compared to the Examples. Therefore, when the linearly oriented resist composition of the Examples is used for ArF-dry exposure, the sensitivity is optimal, and a resist pattern with good LWR, pattern rectangularity, and number of development defects can be formed.

[0583] Preparation of positive-type radiosensitive linear compositions for extreme ultraviolet (EUV) exposure

[0584] [Example 67]

[0585] A mixture of 100 parts by mass of (A-12) as polymer (A), 20.0 parts by mass of (B-1) as radiosensitive linear acid generator (B), 10.0 parts by mass of (D-4) as acid diffusion control agent (D), 3.0 parts by mass of (F-5) as high fluorine content polymer (F) (solid component), and 6,110 parts by mass of a mixed solvent of (E-1) / (E-4) as solvent (E) was prepared by filtering the mixture using a membrane filter with a pore size of 0.2 μm.

[0586] [Examples 68-79 and Comparative Examples 7-9]

[0587] Using the types and amounts of each component shown in Table 8 below, except that, the radiosensitive linear compositions (J-68) to (J-79) and (CJ-7) to (CJ-9) were prepared in the same manner as in Example 67.

[0588] [Table 8]

[0589]

[0590] <Formation of resist patterns using positive-type radiosensitive linear compositions for EUV exposure>

[0591] Using a spin coater (Tokyo Electron Inc.'s "CLEAN TRACK ACT12"), a lower antireflective film forming composition (Brewer Science's "ARC66") was applied onto a 12-inch silicon wafer, followed by heating at 205°C for 60 seconds to form a lower antireflective film with an average thickness of 100 nm. The prepared EUV exposure positive-type radiosensitive linear composition was then applied onto the lower antireflective film using the same spin coater and subjected to a photomask treatment at 130°C for 60 seconds. Afterward, the wafer was cooled at 23°C for 30 seconds to form a resist film with an average thickness of 40 nm. Next, the resist film was exposed using an EUV exposure apparatus (ASML's "NXE3300") with NA=0.33, conventional illumination conditions (s=0.89), and a mask: imecDEFECT32FFR02. After exposure, the resist film was subjected to PEB treatment at 120°C for 60 seconds. Subsequently, the resist film was alkaline developed using a 2.38% by mass TMAH aqueous solution as an alkaline developer. After development, the film was rinsed with water and then dried to form a positive resist pattern (15 nm line and space pattern).

[0592] <Evaluation>

[0593] For the resist pattern formed using the positive-type radiosensitive linear composition for EUV exposure, the sensitivity, LWR, pattern rectangularity, and number of development defects were evaluated according to the following method. The results are shown in Table 9 below. In addition, the length of the resist pattern was measured using a scanning electron microscope (Hitachi High-Technologies, Inc.'s "CG-5000").

[0594] [sensitivity]

[0595] In the formation of the resist pattern using the positive-type radiosensitive linear composition for EUV exposure, the exposure amount for forming the 15nm line and spatial pattern is set as the optimal exposure amount, and the optimal exposure amount is set as the sensitivity (mJ / cm). 2 Regarding sensitivity, 25 mJ / cm 2 Above and 40 mJ / cm 2 The following conditions are rated as "good", and those below 25 mJ / cm 2 or more than 40 mJ / cm 2 The situation was rated as "poor".

[0596] [LWR]

[0597] Irradiation was performed using the optimal exposure determined from the aforementioned sensitivity evaluation. The mask size was adjusted to form a 15 nm line and spatial pattern, thus creating a resist pattern. The formed resist pattern was observed from above using the aforementioned scanning electron microscope. The linewidth deviation at a total of 500 points was measured, and a 3-sigma value was determined based on the distribution of the measured values. This 3-sigma value was set as LWR (nm). The smaller the LWR value, the less line wobble and the better. Regarding LWR, conditions below 3.0 nm were evaluated as "good," and conditions exceeding 3.0 nm were evaluated as "poor."

[0598] [Pattern Rectangularity]

[0599] For a 15 nm line-space resist pattern formed by irradiation with the optimal exposure determined in the sensitivity evaluation, the cross-sectional shape of the line-space pattern is evaluated using the scanning electron microscope. Regarding the rectangularity of the resist pattern, if the ratio of the length of the lower side to the length of the upper side in the cross-sectional shape is greater than 1.00 and less than 1.05, it is rated "A" (extremely good); if it is greater than 1.05 and less than 1.10, it is rated "B" (good); and if it is greater than 1.10, it is rated "C" (poor).

[0600] [Number of developmental defects]

[0601] A line and space pattern with a linewidth of 15 nm was formed by exposing the resist film at the optimal exposure level, and this was designated as a defect inspection wafer. The number of defects on the defect inspection wafer was measured using a defect inspection apparatus (KLA-Tencor's "KLA2810"). Defects with a diameter of 50 μm or less were identified as originating from the resist film, and their number was calculated. Regarding the number of defects after development, cases where the number of defects identified as originating from the resist film was 50 or less were evaluated as "good," and cases where the number exceeded 50 were evaluated as "bad."

[0602] [Table 9]

[0603]

[0604] Based on the results in Table 9, it is clear that the radiosensitive linear composition of the Examples exhibits good sensitivity, LWR, pattern rectangularity, and number of development defects when used for EUV exposure. In contrast, the Comparative Examples show poorer characteristics compared to the Examples.

[0605] [Preparation of negative-type radiometric linear composition for ArF exposure, formation and evaluation of resist patterns using the composition]

[0606] [Example 80]

[0607] A mixture of 100 parts by mass of (A-8) as polymer (A), 12.0 parts by mass of (B-3) as radiosensitive linear acid generator (B), 2.0 parts by mass of radiosensitive linear acid generator (b-12), 10.0 parts by mass of (D-7) as acid diffusion control agent (D), 2.0 parts by mass of (F-3) as high fluorine content polymer (F) (solid component), and 3,230 parts by mass of a mixed solvent of (E-1) / (E-2) / (E-3) as solvent (E) was prepared by filtering the mixture using a membrane filter with a pore size of 0.2 μm.

[0608] Using a spin coater (Tokyo Electron Inc.'s "CLEAN TRACK ACT12"), a lower antireflective film forming composition (Brewer Science's "ARC66") was applied onto a 12-inch silicon wafer, followed by heating at 205°C for 60 seconds to form a lower antireflective film with an average thickness of 100 nm. The prepared ArF exposure negative radiosensitive linear composition (J-80) was then applied onto the lower antireflective film using the same spin coater and pre-baked at 100°C for 60 seconds (PB). Afterward, it was cooled at 23°C for 30 seconds to form a resist film with an average thickness of 120 nm. Next, the resist film was exposed using an ArF excimer laser immersion exposure apparatus (ASML's "TWINSCAN XT-1900i") with optical conditions of NA=1.35 and annular (σ=0.8 / 0.6), to create a mask pattern with 40 nm apertures and 80 nm spacing. After exposure, it was baked (PEB) at 100°C for 60 seconds. Subsequently, the resist film was developed using n-butyl acetate as an organic solvent and dried, thereby forming a negative resist pattern (a contact hole pattern with 40 nm apertures and 80 nm spacing).

[0609] For resist patterns using the aforementioned ArF exposure negative-sensitive linear radiometric composition, sensitivity is evaluated in the same manner as for resist patterns using the aforementioned ArF exposure positive-sensitive linear radiometric composition. Additionally, CDU, pattern circularity, and number of development defects are evaluated according to the following methods.

[0610] [CDU]

[0611] Contact holes with a spacing of 40 nm and an 80 nm pitch were formed by irradiation with the optimal exposure amount determined in the aforementioned sensitivity evaluation. The formed resist pattern was observed from the top of the pattern using the aforementioned scanning electron microscope. The diameter deviation of a total of 500 contact holes was measured, and a 3-sigma value was determined based on the distribution of the measured values. This 3-sigma value was set as CDU (nm). The smaller the CDU value, the smaller the roughness of the hole and the better. Regarding CDU, cases with a roughness of less than 3.5 nm were evaluated as "good", and cases with a roughness of more than 3.5 nm were evaluated as "poor".

[0612] [Circularity of the pattern]

[0613] For contact holes with a 40 nm aperture and an 80 nm spacing formed by irradiation with the optimal exposure determined in the aforementioned sensitivity evaluation, the longitudinal and transverse dimensions are measured using the aforementioned scanning electron microscope under top-down view. If the ratio of the longitudinal dimension to the transverse dimension is 0.95 or higher but less than 1.05, the evaluation is "A" (Excellent); if it is 0.90 or higher but less than 0.95, or 1.05 or higher but less than 1.10, the evaluation is "B" (Good); and if it is less than 0.90 or higher than 1.10, the evaluation is "C" (Poor).

[0614] [Number of developmental defects]

[0615] Contact holes with 40 nm apertures and 80 nm spacing were formed by exposing the resist film at the optimal exposure level, and this was designated as a defect inspection wafer. The number of defects on the defect inspection wafer was measured using a defect inspection apparatus (KLA-Tencor's "KLA2810"). Defects with a diameter of 50 μm or less were identified as originating from the resist film, and their number was calculated. Regarding the number of defects after development, cases where the number of defects identified as originating from the resist film was 50 or less were evaluated as "good," and cases where the number exceeded 50 were evaluated as "bad."

[0616] As a result, the radiosensitive linear composition of Example 80 exhibits good sensitivity, CDU, pattern circularity, and number of development defects, even when ArF exposure is used to form a negative resist pattern.

[0617] [Preparation of negative-type radiometric linear composition for EUV exposure, formation and evaluation of resist patterns using the composition]

[0618] [Example 81]

[0619] 100 parts by mass of (A-15) as polymer (A), 30.0 parts by mass of (B-12) as radiosensitive linear acid generator (B), 9.0 parts by mass of radiosensitive linear acid generator (b-11), 10.0 parts by mass of (D-4) as acid diffusion control agent (D), 5.0 parts by mass of (F-5) as high fluorine content polymer (F) (solid component), and 6,110 parts by mass of a mixed solvent of (E-1) / (E-4) / (E-6) as solvent (E) were mixed and filtered using a membrane filter with a pore size of 0.2 μm to prepare a radiosensitive linear composition (J-81).

[0620] Using a spin coater (Tokyo Electron Inc.'s "CLEAN TRACK ACT12"), a lower antireflective film forming composition (Brewer Science's "ARC66") was applied onto a 12-inch silicon wafer, followed by heating at 205°C for 60 seconds to form a lower antireflective film with an average thickness of 100 nm. The prepared EUV exposure negative-type radiosensitive linear composition (J-81) was then applied onto the lower antireflective film using the same spin coater and subjected to a heat treatment at 130°C for 60 seconds. Afterward, it was cooled at 23°C for 30 seconds to form a resist film with an average thickness of 50 nm. Next, the resist film was exposed using an EUV exposure apparatus (ASML's "NXE3300") with NA=0.33, conventional illumination conditions (s=0.89), and an imecDEFECT32FFR15 mask. After exposure, PEB was applied at 120°C for 60 seconds. Subsequently, the resist film was developed using n-butyl acetate as an organic solvent and dried to form a negative resist pattern (a contact hole pattern with 20 nm holes and a 30 nm spacing).

[0621] The resist pattern using the negative radiosensitive linear composition for EUV exposure was evaluated in the same manner as the resist pattern using the negative radiosensitive linear composition for ArF exposure. As a result, the radiosensitive linear composition of Example 81 exhibited good sensitivity, CDU, pattern circularity, and number of development defects even when a negative resist pattern was formed using EUV exposure.

[0622] Industrial availability

[0623] According to the described linear photosensitive composition and resist patterning method, resist patterns exhibiting good sensitivity to exposure light and excellent LWR, pattern rectangularity, CDU, pattern circularity, and development defect count can be formed. Therefore, these are preferably used in the fabrication processes of semiconductor devices that are intended to be further miniaturized in the future.

Claims

1. A radiosensitive composition comprising: Polymer (A) containing structural units (I) with acid-dissociable groups. The following formula (1) represents the radiosensitive linear acid generator (B), and Solvent (E). [Chemistry 1] (In the above formula (1), R 1 It can be a hydrogen atom, nitro group, hydroxyl group, cyano group, carboxyl group, thiol group, halogen atom, or a monovalent organic group. In R 1 In the case of multiple Rs, multiple Rs 1 They are the same or different. R 2 It is a monovalent organic group with 1 to 40 carbon atoms. m is an integer from 1 to 5. M + It is a monovalent onium cation.

2. The radiosensitive linear composition according to claim 1, wherein, The R 2 The monovalent organic group represented includes at least one bond selected from the group consisting of ester, amide, ether, sulfonyl, carbonyl, thioether and carbonate bonds.

3. The radiosensitive linear composition according to claim 1, wherein, The R 2 The monovalent organic group represented contains a cyclic structure.

4. The radiosensitive linear composition according to claim 1, wherein, The content of the radiosensitive linear acid generator (B) is more than 1 part by mass and less than 30 parts by mass relative to 100 parts by mass of the polymer (A).

5. The radiosensitive linear composition according to claim 1, wherein, The structural unit (I) with acid-dissociable groups is represented by the following formula (2). [Chemistry 2] (In the above formula (2), R α It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R A1 It consists of hydrogen atoms or monovalent hydrocarbon groups with 1 to 20 carbon atoms. R A2 and R A3 Each is independently a monovalent chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R A2 and R A3 These are divalent alicyclic groups with 3 to 20 carbon atoms that combine with each other and together with the carbon atoms they are bonded to form. m11 and m12 are each independently 0 or 1. Specifically, when m11 is 1, m12 is 1. When m11 is 0, L A1 Indicates a single bond or a divalent linker; when m11 is 1, L A1 (It is a divalent linker).

6. The radiosensitive linear composition according to claim 1, wherein, The polymer (A) also contains structural units having phenolic hydroxyl groups.

7. The radiosensitive linear composition according to claim 1, wherein, The onium cation is a sulfonium cation or a monazonium cation.

8. The radiosensitive linear composition according to claim 1, further comprising an acid diffusion control agent (D).

9. A method for forming a pattern, comprising: The process of directly or indirectly coating a substrate with the radiosensitive linear composition as described in any one of claims 1 to 8 to form a resist film; The process of exposing the resist film; and The process of developing the exposed resist film.

10. The pattern forming method according to claim 9, wherein, The exposure is performed using a KrF excimer laser, an ArF excimer laser, or extreme ultraviolet light.

11. A radiosensitive linear acid generator, represented by the following formula (1). [Chemistry 3] (In the above formula (1), R 1 It can be a hydrogen atom, nitro group, hydroxyl group, cyano group, carboxyl group, thiol group, halogen atom, or a monovalent organic group. In R 1 In the case of multiple Rs, multiple Rs 1 They are the same or different. R 2 It is a monovalent organic group with 1 to 40 carbon atoms. m is an integer from 1 to 5. M + It is a monovalent onium cation.

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