Polymer, chemically amplified negative resist composition, and resist pattern forming process

Abstract

To provide a chemically amplified negative resist composition comprising a polymer-bound acid generator having superior etching resistance, organic solvent solubility, and moderate acid strength, and capable of generating an acid with low diffusion, and a pattern forming process using the chemically amplified resist composition.SOLUTION: A polymer comprising a repeating unit represented by formula (A1) and a repeating unit of a specific structure having a phenolic hydroxyl group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polymer, a chemically amplified negative resist composition, and a method of forming a resist pattern. [Background technology]

[0002] In recent years, with the increasing integration and speed of LSIs, pattern rules have been rapidly becoming finer. Chemically amplified resist compositions using acid as a catalyst are used exclusively for processing patterns of 0.2 μm or less. High-energy beams such as ultraviolet, far ultraviolet, and electron beams (EB) are used as exposure sources. EB lithography, which is used as an ultrafine processing technology, is also indispensable as a method for processing photomask blanks when producing photomasks for semiconductor manufacturing.

[0003] Polymers containing a large amount of aromatic skeletons with acidic side chains, such as polyhydroxystyrene, are useful as materials for resist compositions for KrF lithography, which uses a KrF excimer laser, but because they exhibit high absorption of light with wavelengths around 200 nm, they have not been used as materials for resist compositions for ArF lithography, which uses an ArF excimer laser.However, they are important materials for resist compositions for EB lithography, a powerful technology for forming patterns smaller than the processing limit of ArF excimer lasers, and for extreme ultraviolet (EUV) lithography, because they provide high etching resistance.

[0004] Resist compositions include positive-type resists in which the exposed areas dissolve, and negative-type resists in which the exposed areas remain as a pattern, and the type that is easiest to use can be selected depending on the resist pattern required. Chemically amplified negative-type resist compositions usually contain a polymer that dissolves in an aqueous alkaline developer, an acid generator that decomposes in the presence of exposure light to generate acid, and a crosslinking agent that uses the acid as a catalyst to form crosslinks between the polymers, making them insoluble in the developer (in some cases, the polymer and crosslinking agent are integrated), and a basic compound is usually added to control the diffusion of the acid generated by exposure.

[0005] A large number of negative resist compositions using phenol units as alkali-soluble units constituting the polymer soluble in the aqueous alkaline developer have been developed, particularly for exposure with KrF excimer laser light. These have not been used for ArF excimer laser light because the phenol units do not transmit light when the exposure light has a wavelength of 150 to 220 nm. However, in recent years, these have once again attracted attention as negative resist compositions for EB or EUV exposure, which are exposure methods for obtaining finer patterns. For example, those described in Patent Documents 1, 2, and 3 have been proposed as resist compositions that provide very high resolution even when used in thin films.

[0006] In addition to the above, numerous materials have been developed for use in chemically amplified negative resist compositions. For example, crosslinking agents, such as those described in Patent Documents 1 to 3, are used to insolubilize alkali-soluble polymers used in resist compositions that impart a negative mechanism through the action of acid generated upon irradiation with high-energy rays, and many crosslinking agents have been developed. Numerous attempts have also been made to impart the functionality of these crosslinking agents to polymers. Examples include introducing styrene units substituted with alkoxymethoxy groups (Patent Document 4), introducing repeating units having alkoxymethylamino groups (Patent Document 5), introducing repeating units having epoxy groups (Patent Document 6), introducing styrene-based repeating units having acid-dissociable groups (Patent Document 7), introducing adamantyl-based repeating units having acid-dissociable hydroxy groups (Patent Document 8), and introducing aliphatic hydrocarbon and alicyclic hydrocarbon-based repeating units having acid-dissociable hydroxy groups (Patent Documents 9, 10, and 11). Materials having acid-dissociable hydroxy groups have also been proposed in Patent Document 12, etc.

[0007] To suppress acid diffusion, resist compounds containing repeating units derived from onium salts of sulfonic acids with polymerizable unsaturated bonds have been proposed (Patent Document 13). Such so-called polymer-bound acid generators are characterized by extremely short acid diffusion times because they generate polymeric sulfonic acids upon exposure. Furthermore, increasing the proportion of acid generator can improve sensitivity. Increasing the amount of additive-type acid generators also increases sensitivity, but this also increases the acid diffusion distance. Because acid diffuses unevenly, increased acid diffusion leads to deterioration of LER and CDU. While polymer-bound acid generators offer excellent balance between sensitivity, LER, and CDU, the development of acid generators that generate acids with more suitable strengths is desirable.

[0008] Patent Documents 14 and 15 describe examples of controlling acid diffusion by binding sulfonic acid, which is generated upon exposure as an acid generator that generates acid of a more suitable strength, to a polymer used in a resist composition to suppress diffusion. This method of suppressing acid diffusion by incorporating a repeating unit that generates acid upon exposure into a base polymer is effective for obtaining patterns with small LER. However, depending on the structure and incorporation rate of such repeating units, problems may arise with the solubility of base polymers bound to repeating units that generate acid upon exposure in organic solvents.

[0009]

[0003] With the recent progress in miniaturization of resist patterns, problems such as collapse of the resist pattern during development and poor resistance in the etching process have become an issue. Although the introduction of a repeating unit derived from an onium salt of a sulfonic acid having a polymerizable unsaturated bond has suppressed the acid diffusion of the generated acid to some extent, there remains room for improvement in various lithography performances, collapse of the resist pattern, and poor etching resistance. In order to meet the future demands for miniaturization, it is extremely important to develop a polymer-type acid generator that combines lithography performance with good resist pattern collapse and etching resistance. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-276910 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-164933 [Patent Document 3] Japanese Patent Application Laid-Open No. 2008-249762 [Patent Document 4] Japanese Patent Application Publication No. 5-232702 [Patent Document 5] Japanese Patent Application Publication No. 8-202037 [Patent Document 6] Japanese Patent Application Laid-Open No. 2001-226430 [Patent Document 7] Japanese Patent Application Laid-Open No. 2003-337414 [Patent Document 8] Japanese Patent Application Laid-Open No. 2001-154357 [Patent Document 9] U.S. Patent No. 7,300,739 [Patent Document 10] U.S. Patent No. 7,393,624 [Patent Document 11] U.S. Patent No. 7,563,558 [Patent Document 12] Japanese Patent Application Laid-Open No. 2013-164588 [Patent Document 13] Japanese Patent Application Laid-Open No. 2012-177834 [Patent Document 14] Japanese Patent Application Laid-Open No. 2011-22564 [Patent Document 15] International Publication No. 2015 / 194330 Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a chemically amplified negative resist composition that contains a polymer-bonded acid generator that has excellent etching resistance, organic solvent solubility, and appropriate acid strength, and is capable of generating an acid that diffuses little, and a method of forming a resist pattern that uses the chemically amplified resist composition. [Means for solving the problem]

[0012] As a result of extensive research into achieving the above-mentioned object, the present inventors have found that by using, as a polymer-bound acid generator, a polymer containing a repeating unit derived from a sulfonium salt that contains an aromatic sulfonate anion having an aromatic ring substituted with a vinyl group, it is possible to obtain a chemically amplified resist composition that has improved LER, high contrast, high resolution, etching resistance, and excellent suppression of development defects, and have completed the present invention.

[0013] That is, the present invention provides the following polymer, chemically amplified negative resist composition, and method of forming a resist pattern. 1. A polymer comprising a repeating unit represented by the following formula (A1) and a repeating unit represented by the following formula (A2): [ka] (In the formula, n1 is an integer of 0 to 2. n2 is an integer that satisfies 0≦n2≦5+2(n1)−1. p is an integer of 1 to 5. q is an integer of 1 to 3. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 1 represents a halogen atom, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 10 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 10 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 10 carbon atoms which may be substituted with a halogen atom, or a fluorinated saturated hydrocarbylthio group having 1 to 10 carbon atoms. R 2 is a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. R 3 is a (p+1)-valent hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom. R 4 represents a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 5 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 5 carbon atoms, a fluorinated saturated hydrocarbylcarbonyloxy group having 1 to 5 carbon atoms, a fluorinated saturated hydrocarbyloxycarbonyl group having 1 to 5 carbon atoms, or a fluorinated saturated hydrocarbylthio group having 1 to 5 carbon atoms, and some of the hydrogen atoms of these groups may be substituted with at least one selected from a hydroxy group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, and a cyano group, and at least one selected from an ester bond, an ether bond, a sulfonate ester bond, a carbonate bond, and a carbamate bond may be present between the carbon-carbon bonds of these groups. When q is 1, two R 2 and R 3Any two of R may be bonded to each other to form a ring together with the sulfur atom to which they are attached. When q is 2, two R 3 and R 2 Any two of R may be bonded to each other to form a ring together with the sulfur atom to which they are attached. When q is 3, three R 3 Any two of may be bonded to each other to form a ring together with the sulfur atom to which they are attached. [ka] (In the formula, a1 is 0 or 1. a2 is an integer of 0 to 2. a3 is an integer that satisfies 0≦a3≦5+2(a2)−a4. a4 is an integer of 1 to 3. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 11 is a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. A 1 represents a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and some of the -CH2- in the saturated hydrocarbylene group may be substituted with -O-. 2. The polymer of 1, wherein the sulfonium salt is represented by the following formula (A1-1): [ka] (In the formula, n1, n2, p, q, R A , R 1 and R 4 is the same as above. R 5 and R 6 are each independently a halogen atom other than a fluorine atom, a nitro group, a cyano group or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. r 1 and r 2are each independently an integer of 0 to 2. 1 is 0≦s 1 ≦(2r 1 +4). 2 is 0≦s 2 ≦(2r 2 +4). 3.R 4 is a fluorine atom, a trifluoromethyl group, a trifluoromethoxy group or a trifluoromethylthio group. 4. The polymer of 1 further comprising a repeating unit represented by the following formula (A3): [ka] (In the formula, b1 is 0 or 1. b2 is an integer of 0 to 2. b3 is an integer that satisfies 0≦b3≦5+2(b2)−b4. b4 is an integer of 1 to 3. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 12 is a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. R 13 and R 14 are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms which may be substituted with a hydroxy group or a saturated hydrocarbyloxy group, or an aryl group which may have a substituent, provided that R 13 and R 14 cannot be hydrogen atoms at the same time. 13 and R 14 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. A 2 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and some of the -CH2- in the saturated hydrocarbylene group may be substituted with -O-. W1 is a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, or an aryl group which may have a substituent. 5. The polymer according to 4, wherein the polymer contains a repeating unit represented by the following formula (A2-1), and a repeating unit represented by the following formula (A3-1) or a repeating unit represented by the following formula (A3-2). [ka] (In the formula, a3, a4, b4, R A , R B , Y 2 , R 11 , R 13 , R 14 is the same as above.) 6. A polymer according to claim 1, further comprising at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (A4), a repeating unit represented by the following formula (A5), and a repeating unit represented by the following formula (A6). [ka] (In the formula, c and d each independently represent an integer of 0 to 4. e1 is 0 or 1. e2 is an integer of 0 to 2. e3 is an integer of 0 to 5.) R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 21 and R 22 are each independently a hydroxy group, a halogen atom, a saturated hydrocarbyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. R 23is a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms, a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, a saturated hydrocarbylsulfinyl group having 1 to 20 carbon atoms, or a saturated hydrocarbylsulfonyl group having 1 to 20 carbon atoms. A 3 represents a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and some of the -CH2- in the saturated hydrocarbylene group may be substituted with -O-. 7. A chemically amplified negative resist composition comprising a base polymer comprising the polymer of (A)1. 8. The chemically amplified negative resist composition of 7, wherein the base polymer further comprises a polymer containing a repeating unit represented by formula (A2) and a repeating unit represented by the following formula (A3), but does not contain a repeating unit represented by formula (A1): [ka] (In the formula, b1 is 0 or 1. b2 is an integer of 0 to 2. b3 is an integer that satisfies 0≦b3≦5+2(b2)−b4. b4 is an integer of 1 to 3. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 12 is a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. R 13 and R 14 are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms which may be substituted with a hydroxy group or a saturated hydrocarbyloxy group, or an aryl group which may have a substituent, provided that R 13 and R14 cannot be hydrogen atoms at the same time. 13 and R 14 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. A 2 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and some of the -CH2- in the saturated hydrocarbylene group may be substituted with -O-. W 1 is a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, or an aryl group which may have a substituent. 9. The chemically amplified negative resist composition of 7, wherein the content of repeating units having an aromatic ring skeleton among all repeating units of the polymer contained in the base polymer is 60 mol % or more. 10. The chemically amplified negative resist composition of 7, further comprising (B) a quencher. 11. The chemically amplified negative resist composition of 7, further comprising (C) a photoacid generator. 12. The chemically amplified negative resist composition of 7, wherein the content ratio of (C) the photoacid generator to (B) the quencher is less than 6 by mass ratio. 13. The chemically amplified negative resist composition of 7, further comprising (D) a crosslinking agent. 14. The chemically amplified negative resist composition of 7, which does not contain a crosslinking agent. 15. The chemically amplified negative resist composition of 7, further comprising (E) a fluorine atom-containing polymer which contains at least one selected from the group consisting of a repeating unit represented by the following formula (E1), a repeating unit represented by the following formula (E2), a repeating unit represented by the following formula (E3), and a repeating unit represented by the following formula (E4), and which may further contain at least one selected from the group consisting of a repeating unit represented by the following formula (E5) and a repeating unit represented by the following formula (E6). [ka] (In the formula, x is an integer of 1 to 3. y is an integer that satisfies 0≦y≦5+2z−x. z is 0 or 1. h is an integer of 1 to 3. R Bare each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R C are each independently a hydrogen atom or a methyl group. R 301 , R 302 , R 304 and R 305 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. R 303 , R 306 , R 307 and R 308 are each independently a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or an acid labile group, and R 303 , R 306 , R 307 and R 308 When is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be present between the carbon-carbon bonds. R 309 is a hydrogen atom or a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a group containing a hetero atom interposed between its carbon-carbon bond. R 310 is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a group containing a hetero atom interposed between its carbon-carbon bond. R 311 is a saturated hydrocarbyl group having 1 to 20 carbon atoms in which at least one hydrogen atom has been substituted with a fluorine atom, and some of the -CH2- groups in the saturated hydrocarbyl group may be substituted with an ester bond or an ether bond. Z 1 is a (g+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (g+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. Z 2 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * is a bond to a carbon atom in the main chain. Z 3 is a single bond, -O-, *-C(=O)-OZ 31 -Z 32-or*-C(=O)-NH-Z 31 -Z 32 -It is. Z 31 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms. 32 is a single bond, an ester bond, an ether bond, or a sulfonamide bond. * is a bond to a carbon atom in the main chain. 16. The chemically amplified negative resist composition of 7, further comprising (F) an organic solvent. 17. A method for forming a resist pattern, comprising the steps of: forming a resist film on a substrate using the chemically amplified negative resist composition according to any one of 7 to 16; irradiating the resist film with a pattern using high-energy rays; and developing the resist film irradiated with the pattern using an alkaline developer. 18. The method for forming a resist pattern according to 17, wherein the high-energy radiation is extreme ultraviolet radiation or an electron beam. 19. The method for forming a resist pattern according to claim 17, wherein the outermost surface of the substrate is made of a material containing at least one selected from the group consisting of chromium, silicon, tantalum, molybdenum, cobalt, nickel, tungsten, and tin. 20. The method for forming a resist pattern according to 17, wherein the substrate is a transmissive or reflective mask blank. 21. A transmission or reflection mask blank coated with any one of the chemically amplified negative resist compositions set forth in any one of 7 to 16. [Effects of the Invention]

[0014] Polymers containing repeating units represented by formula (A1) have good solvent solubility and, due to the rigid structure of the aromatic sulfonic acid structure, have the characteristic of small acid diffusion. Therefore, negative resist compositions containing the polymer can prevent a decrease in resolution due to blurring of acid diffusion, and also have optimal acid strength, making it possible to improve resolution, LER, and development defects. In addition, the aromatic ring acts as a good etching-resistant group, making them suitable for forming fine patterns. [Brief explanation of the drawings]

[0015] [Figure 1]1 is a nuclear magnetic resonance spectrum ( 1 H-NMR / DMSO-d 6 ) of the monomer PM-1 synthesized in Synthesis Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described in detail below. In the following description, some structures represented by chemical formulas may have asymmetric carbon atoms, and enantiomers or diastereomers may exist. In such cases, a single formula will be used to represent all isomers. These isomers may be used singly or as a mixture.

[0017] [polymer] The polymer of the present invention contains a repeating unit derived from a sulfonium salt type monomer represented by the following formula (A1) (hereinafter also referred to as repeating unit A1). [ka]

[0018] In formula (A1), n1 is an integer of 0 to 2 and is selected from benzene rings such as benzene rings, naphthalene rings, anthracene rings, and phenanthrene rings, or condensed polycyclic aromatic groups consisting of three or less aromatic rings. From the viewpoint of solvent solubility, n1 is preferably a benzene ring where n1 is 0.

[0019] In formula (A1), n2 is an integer that satisfies 0≦n2≦5+2(n1)−1, and when n1 is 0, n2 is preferably 0, 1, 2, or 3, and more preferably 0. When n1 is 1 or 2, n2 is preferably 0, 1, 2, 3, or 4.

[0020] In formula (A1), p is an integer of 1 to 5, and from the viewpoint of raw material procurement, is preferably 1, 2 or 3, and more preferably 1 or 2. q is an integer of 1 to 3, and is preferably 1 or 2, and more preferably 1.

[0021] In formula (A1), R Ais a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0022] In formula (A1), R 1 is a halogen atom, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 10 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 10 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 10 carbon atoms which may be substituted with a halogen atom, or a fluorinated saturated hydrocarbylthio group having 1 to 10 carbon atoms. The saturated hydrocarbyl group and the saturated hydrocarbyl moiety of the saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, and saturated hydrocarbylthio group may be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 10 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, butyl, pentyl, and hexyl; cycloalkyl groups having 3 to 10 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; and groups obtained by combining these. When the number of carbon atoms is equal to or less than the upper limit, the solubility in an alkaline developer is good. When n2 is 2 or more, each R 1 may be the same as or different from each other.

[0023] In formula (A1), R 2is a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl; saturated cyclic hydrocarbyl groups having 3 to 30 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 30 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; unsaturated cyclic hydrocarbyl groups having 3 to 30 carbon atoms, such as cyclohexenyl; aryl groups having 2 to 30 carbon atoms, such as phenyl and naphthyl; aralkyl groups having 7 to 30 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these. Of these, aryl groups are preferred. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH- constituting the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0024] In formula (A1), R 3is a (p+1)-valent hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom. The (p+1)-valent hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include hydrocarbylene groups having 1 to 20 carbon atoms and groups obtained by further eliminating (p-1) hydrogen atoms from the hydrocarbylene group. Examples of the hydrocarbylene group include alkanediyl groups having 1 to 30 carbon atoms, such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, and heptadecane-1,17-diyl group; cyclopentanediyl cyclic saturated hydrocarbylene groups having 3 to 30 carbon atoms such as a phenyl group, a cyclohexanediyl group, a norbornanediyl group, or an adamantanediyl group; arylene groups such as a phenylene group, a methylphenylene group, an ethylphenylene group, an n-propylphenylene group, an isopropylphenylene group, an n-butylphenylene group, an isobutylphenylene group, a sec-butylphenylene group, a tert-butylphenylene group, a naphthylene group, a methylnaphthylene group, an ethylnaphthylene group, an n-propylnaphthylene group, an isopropylnaphthylene group, an n-butylnaphthylene group, an isobutylnaphthylene group, a sec-butylnaphthylene group, or a tert-butylnaphthylene group; and groups obtained by combining these.

[0025] Furthermore, some or all of the hydrogen atoms of the (p+1)-valent hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH2- moieties constituting the (p+1)-valent hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, the hydrocarbon group may contain a hydroxy group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0026] In formula (A1), R 4 represents a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 5 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 5 carbon atoms, a fluorinated saturated hydrocarbylcarbonyloxy group having 1 to 5 carbon atoms, a fluorinated saturated hydrocarbyloxycarbonyl group having 1 to 5 carbon atoms, or a fluorinated saturated hydrocarbylthio group having 1 to 5 carbon atoms, and some of the hydrogen atoms in these groups may be substituted with at least one selected from a hydroxy group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, and a cyano group, and at least one selected from an ester bond, an ether bond, a sulfonate ester bond, a carbonate bond, and a carbamate bond may be present between the carbon-carbon bonds of these groups. 4The sulfonium salt is preferably a fluorine atom, a trifluoromethyl group, a difluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group, a trifluoromethylthio group, or a difluoromethylthio group, more preferably a fluorine atom, a trifluoromethyl group, or a trifluoromethoxy group, and even more preferably a trifluoromethoxy group. In particular, the use of a trifluoromethoxy group significantly improves solvent solubility, relaxes restrictions on the introduction rate of the repeating unit A1, and allows the sulfonium salt to dissolve uniformly in the solvent without agglomeration and to be uniformly dispersed in the resist film. High-energy irradiation generates acid from the uniformly dispersed sulfonium salt, enabling high resolution and improved LER. Furthermore, the inclusion of a fluorine atom in the sulfonium cation moiety controls the solubility of the unexposed areas in an alkaline developer, thereby improving pattern contrast and contributing to improved resolution.

[0027] When q is 1, two R 2 and R 3 Any two of R may be bonded to each other to form a ring together with the sulfur atom to which they are attached. When q is 2, two R 3 and R 2 Any two of R may be bonded to each other to form a ring together with the sulfur atom to which they are attached. When q is 3, three R 3 Any two of these may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, specific examples of the ring include those represented by the following formulas: [ka] (In the formula, the dashed lines represent bonds.)

[0028] The repeating unit A1 is preferably one represented by the following formula (A1-1). [ka] (In the formula, n1, n2, p, q, R A , R 1 and R 4 is the same as above.)

[0029] In formula (A1-1), R 5 and R 6 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom other than a fluorine atom, a nitro group, a cyano group, or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0]. 2,6 ] cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as a decanyl group, an adamantyl group, or an adamantylmethyl group; aryl groups having 6 to 20 carbon atoms, such as a phenyl group, a naphthyl group, or an anthracenyl group; and groups obtained by combining these. In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH2- constituting the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, or a nitrogen atom, so that the hydrocarbyl group may contain a hydroxy group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a carbamate bond, an amide bond, an imide bond, a lactone ring, a sultone ring, a thiolactone ring, a lactam ring, a sultam ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0030] In formula (A1-1), r 1 and r 2are each independently an integer of 0 to 2, and represent a benzene ring when 0, a naphthalene ring when 1, and an anthracene ring when 2. Among these, r is 1 and r 2 is preferably a benzene ring with 0.

[0031] In formula (A1-1), s 1 is 0≦s 1 ≦(2r 1 +4), preferably 0. 2 is 0≦s 2 ≦(2r 2 +4), preferably 0. 1 If ≧2, R is 2 or more 5 may be the same or different, and two or more R 2 may be bonded to each other to form a ring. 2 If ≧2, R is 2 or more 6 may be the same or different, and two or more R 6 may be bonded to each other to form a ring. Examples of the ring include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring.

[0032] Examples of the anion of the repeating unit A1 include, but are not limited to, those shown below. A is the same as above. [ka]

[0033] [ka]

[0034] [ka]

[0035] [ka]

[0036] Examples of the sulfonium cation of the monomer represented by formula (A1) include, but are not limited to, those shown below. [ka]

[0037] [ka]

[0038] [ka]

[0039] [ka]

[0040] [ka]

[0041] [ka]

[0042] [ka]

[0043] [ka]

[0044] [ka]

[0045]

change

[0046]

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[0047]

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[0048]

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[0049]

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[0050]

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[0051]

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[0052]

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[0053]

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[0054]

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[0055]

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[0056]

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[0057]

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[0058]

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[0059]

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[0060]

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[0061]

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[0062]

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[0063]

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[0064]

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[0065] The polymer of the present invention is a polymer-bound photoacid generator that functions as both a photoacid generator and a base polymer in a chemically amplified resist composition. The structural features of the onium salt-type monomer of the present invention include an aromatic vinyl structure as a polymerizable group and an aromatic sulfonate anion. The aromatic ring directly bonded to the main chain of the base polymer makes the main chain of the base polymer rigid, thereby improving the glass transition temperature (Tg) of the base polymer. Interactions between aromatic rings within or between base polymers (π-π stacking effect) are thought to result in the base polymer being regularly arranged, thereby exhibiting resistance to pattern collapse in a developer even during fine pattern formation. Furthermore, the aromatic ring directly bonded to the main chain also exhibits excellent etching resistance during the etching process after fine pattern formation. The aromatic sulfonic acid moiety of the generated acid has a more rigid structure than conventional partially fluorinated alkane sulfonate anions, thereby suppressing excessive acid diffusion. Furthermore, the introduction of fluorine atoms into the sulfonium cation structure ensures solubility in organic solvents. Furthermore, The ionic bond between the anion and cation is optimized, resulting in good solubility in an alkaline developer. Due to these synergistic effects, the polymer of the present invention is capable of forming a pattern that is resistant to pattern collapse, has excellent LER, and exhibits etching resistance and suppression of development defects, making it particularly suitable as a material for a chemically amplified negative resist composition.

[0066] The content of the repeating unit A1 is preferably 0.5 to 30 mol %, more preferably 1 to 15 mol %, and even more preferably 2 to 10 mol %, of all repeating units constituting the polymer. If it exceeds 30 mol %, the solubility in organic solvents will deteriorate, making it impossible to synthesize the desired polymer, or even if it is possible, there is a risk of precipitation, coating defects, and development defects when it is made into a resist composition. The repeating unit A1 may be used alone or in combination of two or more types.

[0067] The polymer further contains a repeating unit represented by the following formula (A2) (hereinafter also referred to as repeating unit A2). [ka]

[0068] In formula (A2), a1 is 0 or 1. a2 is an integer of 0 to 2, and when it is 0, it represents a benzene skeleton, when it is 1, it represents a naphthalene skeleton, and when it is 2, it represents an anthracene skeleton. a3 is an integer that satisfies 0≦a3≦5+2(a2)−a4. a4 is an integer of 1 to 3. When a2 is 0, a3 is preferably 0, 1, 2, or 3, and a4 is preferably 1, 2, or 3. When a2 is 1 or 2, a3 is preferably 0, 1, 2, 3, or 4, and a4 is preferably 1, 2, or 3.

[0069] In formula (A2), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0070] In formula (A2), R 11 is a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. The saturated hydrocarbyl group and the saturated hydrocarbyl moiety of the saturated hydrocarbyloxy group and saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, butyl, pentyl, hexyl, and structural isomers thereof; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; and groups obtained by combining these. When the number of carbon atoms is equal to or less than the upper limit, the solubility in an alkaline developer is good. When a3 is 2 or more, each R 11 may be the same as or different from each other.

[0071] In formula (A2), A 1is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a portion of the -CH2- in the saturated hydrocarbylene group may be substituted with -O-. The saturated hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include alkanediyl groups having 1 to 10 carbon atoms, such as methylene, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, and hexane-1,6-diyl, and structural isomers thereof; cyclic saturated hydrocarbylene groups having 3 to 10 carbon atoms, such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, and cyclohexanediyl; and groups obtained by combining these. When the saturated hydrocarbylene group contains an ether bond, when a1 in formula (A2) is 1, the ether bond may be located anywhere except between the carbon atom at the α-position and the carbon atom at the β-position relative to the ester oxygen atom. When a1 is 0, the atom bonding to the main chain is an etheric oxygen atom, and the second ether bond may be inserted at any position except between the carbon atom at the α-position and the carbon atom at the β-position relative to the etheric oxygen atom. Note that if the number of carbon atoms in the saturated hydrocarbylene group is 10 or less, sufficient solubility in an alkaline developer can be obtained, which is preferable.

[0072] a1 is 0 and A 1 is a single bond, i.e., the aromatic ring is directly attached to the polymer backbone (i.e., the linker (-C(=O)-OA 1 When the repeating unit A2 does not have -), preferred examples of the repeating unit A2 include units derived from 3-hydroxystyrene, 4-hydroxystyrene, 5-hydroxy-2-vinylnaphthalene, 6-hydroxy-2-vinylnaphthalene, etc. In particular, the repeating unit represented by the following formula (A2-1) is preferred. [ka] (In the formula, R A , R 11 , a3 and a4 are the same as above.)

[0073] a1 is 0 and A 1is a single bond (i.e., the linker (-C(=O)-OA 1 In the case where R does not have -), specific examples of the repeating unit A2 include, but are not limited to, those shown below. A is the same as above. [ka]

[0074] [ka]

[0075] Also, a1 is 1 (i.e., -C(=O)-OA as a linker). 1 In the case where R A is the same as above. [ka]

[0076] [ka]

[0077] [ka]

[0078] The content of repeating unit A2 is preferably 10 to 95 mol %, more preferably 40 to 90 mol %, and even more preferably 45 to 85 mol % of all repeating units constituting the polymer. However, when the polymer contains at least one of repeating units represented by formula (A4) and repeating units represented by formula (A5) described below, which impart high etching resistance to the polymer, and this unit has a phenolic hydroxy group as a substituent, the proportion of the repeating unit A2 is also preferably within the above range. Repeating unit A2 may be used alone or in combination of two or more types.

[0079] The polymer may contain a repeating unit represented by the following formula (A3) (hereinafter also referred to as repeating unit A3). [ka]

[0080] When the repeating unit A3 is irradiated with high energy rays, it converts to -OW by the action of the acid generated from the acid generator. 1 This repeating unit undergoes an elimination reaction, which makes the compound insoluble in alkaline developer and induces a crosslinking reaction between polymers. The effect of repeating unit B2 is to promote the negative conversion reaction more efficiently, thereby improving resolution.

[0081] In formula (A3), b1 is 0 or 1. b2 is an integer of 0 to 2. b3 is an integer that satisfies 0≦b3≦5+2(b2)−b4. b4 is an integer of 1 to 3.

[0082] In formula (A3), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0083] In formula (A3), R 12is a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. The saturated hydrocarbyl group and the saturated hydrocarbyl moiety of the saturated hydrocarbyloxy group and saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic, and specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, and structural isomers thereof; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; and groups obtained by combining these. When b3 is 2 or more, each R 12 may be the same as or different from each other.

[0084] In formula (A3), R 13 and R 14 are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms which may be substituted with a hydroxy group or a saturated hydrocarbyloxy group, or an aryl group which may have a substituent, provided that R 13 and R 14 cannot be hydrogen atoms at the same time. 13 and R 14 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. 13 and R 14 Preferred examples of the alkyl group include alkyl groups such as methyl, ethyl, propyl, and butyl groups, and structural isomers thereof, as well as alkyl groups in which some of the hydrogen atoms have been substituted with hydroxy groups or saturated hydrocarbyloxy groups.

[0085] In formula (A3), A 2is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and some of the -CH2- in the saturated hydrocarbylene group may be substituted with -O-. The saturated hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include alkanediyl groups such as methylene, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, and hexane-1,6-diyl, and structural isomers thereof; cyclic saturated hydrocarbylene groups such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, and cyclohexanediyl; and groups obtained by combining these. When the saturated hydrocarbylene group contains an ether bond, when b1 in formula (B2) is 1, the ether bond may be located anywhere except between the carbon atom α and the carbon atom β to the ester oxygen atom. When b1 is 0, the atom bonding to the main chain is an ether oxygen atom, and the second ether bond may be inserted anywhere except between the carbon atom at the α-position and the carbon atom at the β-position relative to the ether oxygen atom.

[0086] In formula (A3), W 1 is a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, or an aryl group which may have a substituent. The aliphatic hydrocarbyl group may be linear, branched, or cyclic, and specific examples thereof include alkyl groups such as methyl, ethyl, propyl, and isopropyl; and cyclic aliphatic hydrocarbyl groups such as cyclopentyl, cyclohexyl, and adamantyl. Examples of the aryl group include a phenyl group. In addition, a portion of the -CH2- in the aliphatic hydrocarbyl group may be substituted with -O-, -C(=O)-, -OC(=O)-, or -C(=O)-O-. The -CH2- in the hydrocarbyl group may be bonded to an oxygen atom in formula (B2). Examples of such substituted groups include a methylcarbonyl group.

[0087] The repeating unit A3 is preferably one represented by the following formula (A3-1) or (A3-2). [ka] (In the formula, b4, R A , R 13 and R 14 is the same as above.)

[0088] Preferred examples of the repeating unit A3 include, but are not limited to, the following: A is the same as above, Me is a methyl group, and Ac is an acetyl group. [ka]

[0089] [ka]

[0090] [ka]

[0091] [ka]

[0092] [ka]

[0093] The repeating unit A3 may be used alone or in combination of two or more.

[0094] For the purpose of improving etching resistance, the polymer may contain at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (A4) (hereinafter also referred to as repeating unit A4), a repeating unit represented by the following formula (A5) (hereinafter also referred to as repeating unit A5), and a repeating unit represented by the following formula (A6) (hereinafter also referred to as repeating unit A6). [ka]

[0095] In the formulae (A4) and (A5), c and d each independently represent an integer of 0 to 4.

[0096] In formulas (A4) and (A5), R 21 and R 22 are each independently a hydroxy group, a halogen atom, a saturated hydrocarbyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, and saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic. When d is 2 or more, each R 21 may be the same or different. When e is 2 or more, each R 22 may be the same as or different from each other.

[0097] In formula (A6), e1 is 0 or 1. e2 is an integer of 0 to 2, and when it is 0, it represents a benzene skeleton, when it is 1, it represents a naphthalene skeleton, and when it is 2, it represents an anthracene skeleton. e3 is an integer of 0 to 5. When e2 is 0, e3 is preferably 0, 1, 2, or 3, and when e2 is 1 or 2, e3 is preferably 0, 1, 2, 3, or 4.

[0098] In formula (A6), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 23is a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms, a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, a saturated hydrocarbylsulfinyl group having 1 to 20 carbon atoms, or a saturated hydrocarbylsulfonyl group having 1 to 20 carbon atoms. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, saturated hydrocarbyloxyhydrocarbyl group, saturated hydrocarbylthiohydrocarbyl group, saturated hydrocarbylsulfinyl group, and saturated hydrocarbylsulfonyl group may be linear, branched, or cyclic. When e3 is 2 or more, each R 23 may be the same as or different from each other.

[0099] R 23 Preferred examples of the alkyl group include halogen atoms such as fluorine, chlorine, bromine, and iodine atoms; trifluoromethyl, trifluoromethoxy, nitro, and cyano groups; saturated hydrocarbyl groups such as methyl, ethyl, propyl, butyl, tert-butyl, pentyl, hexyl, cyclopentyl, and cyclohexyl groups, and structural isomers of these groups; and saturated hydrocarbyloxy groups such as methoxy, ethoxy, propoxy, butoxy, tert-butoxy, pentyloxy, hexyloxy, cyclopentyloxy, and cyclohexyloxy groups, and structural isomers of these hydrocarbon moieties.

[0100] Furthermore, saturated hydrocarbyl carbonyloxy groups can be easily introduced by chemical modification even after polymer polymerization and can be used to finely adjust the solubility of the base polymer in alkaline developers. Examples of the saturated hydrocarbyl carbonyloxy group include methyl carbonyloxy groups, ethyl carbonyloxy groups, propyl carbonyloxy groups, butyl carbonyloxy groups, pentyl carbonyloxy groups, hexyl carbonyloxy groups, cyclopentyl carbonyloxy groups, cyclohexyl carbonyloxy groups, benzoyloxy groups, and structural isomers of the hydrocarbon moieties thereof. If the number of carbon atoms is 20 or less, the effect of controlling and adjusting (mainly the effect of reducing) the solubility of the base polymer in alkaline developers can be made appropriate, and the occurrence of scum (development defects) can be suppressed.

[0101] Among the above-mentioned preferable substituents, particularly useful substituents that are easy to prepare as a monomer include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a methyl group, an ethyl group, a methoxy group, a trifluoromethyl group, a trifluoromethoxy group, a nitro group, and a cyano group.

[0102] In formula (A6), A 3is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a portion of the -CH2- in the saturated hydrocarbylene group may be substituted with -O-. The saturated hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include alkanediyl groups having 1 to 10 carbon atoms, such as methylene, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, and hexane-1,6-diyl, and structural isomers thereof; cyclic saturated hydrocarbylene groups having 1 to 10 carbon atoms, such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, and cyclohexanediyl; and groups obtained by combining these. When the saturated hydrocarbylene group contains an ether bond, when e1 in formula (A6) is 1, the ether bond may be located anywhere except between the carbon atom at the α-position and the carbon atom at the β-position relative to the ester oxygen atom. When e1 is 0, the atom bonding to the main chain is an etheric oxygen atom, and the second ether bond may be inserted at any position except between the carbon atom at the α-position and the carbon atom at the β-position relative to the etheric oxygen atom. Note that if the number of carbon atoms in the saturated hydrocarbylene group is 10 or less, sufficient solubility in an alkaline developer can be obtained, which is preferable.

[0103] e1 is 0 and A 3 is a single bond, that is, the aromatic ring is directly bonded to the main chain of the polymer (i.e., the linker (-C(=O)-OA 3 When the repeating unit A6 does not have -), preferred examples of the repeating unit A6 include units derived from styrene, 4-chlorostyrene, 4-methylstyrene, 4-methoxystyrene, 4-bromostyrene, 4-acetoxystyrene, 2-hydroxypropylstyrene, 2-vinylnaphthalene, 3-vinylnaphthalene, etc.

[0104] Also, when e1 is 1 (i.e., -C(=O)-OA as a linker 3 In the case where R A is the same as above. [ka]

[0105] [ka]

[0106] When at least one of the repeating units A4 to A6 is used as a structural unit of the polymer, the addition of a ring structure to the main chain provides the effect of improving the etching resistance of the aromatic ring as well as the resistance to EB irradiation during pattern inspection.

[0107] To obtain the effect of improving etching resistance, the content of repeating units A4 to A6 is preferably 5 mol % or more of all repeating units constituting the polymer. Furthermore, the content of repeating units A4 to A6 is preferably 35 mol % or less, more preferably 30 mol % or less, of all repeating units constituting the polymer. When no functional group is present or the functional group is other than a hydroxy group, it is preferable that the amount introduced is 35 mol % or less, since this does not cause development defects. Repeating units A4 to A6 may be used singly or in combination of two or more.

[0108] The polymer preferably contains repeating unit A1, repeating unit A2, and at least one selected from repeating units A3 to A6, because this polymer excels in achieving both high etching resistance and high resolution. In this case, these repeating units preferably account for 60 mol % or more, more preferably 80 mol % or more, and even more preferably 100 mol % of all repeating units constituting the polymer.

[0109] From the viewpoint of etching resistance, the polymer preferably contains repeating units having an aromatic ring skeleton in a content of 60 mol % or more, more preferably 80 mol % or more, of all repeating units constituting the polymer, and even more preferably all repeating units have an aromatic ring skeleton.

[0110] The polymer may contain commonly used (meth)acrylate units protected with an acid labile group, or (meth)acrylate units having an adhesive group such as a lactone structure or a hydroxy group other than a phenolic hydroxy group. These repeating units allow for fine adjustment of the properties of the resist film, but they do not necessarily have to be included.

[0111] Examples of the (meth)acrylic acid ester unit having the adhesive group include a repeating unit represented by the following formula (A7) (hereinafter also referred to as repeating unit A7), a repeating unit represented by the following formula (A8) (hereinafter also referred to as repeating unit A8), and a repeating unit represented by the following formula (A9) (hereinafter also referred to as repeating unit A9). These units do not exhibit acidity and can be used auxiliary as units that impart adhesion to substrates or units that adjust solubility. [ka]

[0112] In formulas (A7) to (A9), R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 31 is —O— or a methylene group. 32 is a hydrogen atom or a hydroxy group. 33 is a saturated hydrocarbyl group having 1 to 4 carbon atoms. f is an integer of 0 to 3.

[0113] When the repeating units A7 to A9 are contained, the content thereof is preferably 0 to 30 mol %, more preferably 0 to 20 mol %, of all the repeating units constituting the polymer. The repeating units A7 to A9 may be used alone or in combination of two or more.

[0114] The polymer can be synthesized by copolymerizing each monomer, optionally protected with a protecting group, using a known method, followed by a deprotection reaction as needed. The copolymerization reaction is not particularly limited, but is preferably radical polymerization or anionic polymerization. For these methods, see JP 2004-115630 A.

[0115] The polymer preferably has a weight-average molecular weight (Mw) of 1,000 to 50,000, more preferably 2,000 to 30,000. When Mw is 1,000 or more, there is no risk of the conventionally known phenomenon of pattern heads becoming rounded, resulting in reduced resolution and deterioration of LER and CDU. On the other hand, when Mw is 50,000 or less, there is no risk of deterioration of LER and CDU, particularly when forming a pattern with a line width of 100 nm or less. In the present invention, Mw is a value measured in terms of polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran (THF) or dimethylformamide (DMF) as a solvent.

[0116] The polymer preferably has a narrow molecular weight distribution (Mw / Mn) of 1.0 to 2.2, particularly 1.0 to 2.0. When the polymer has such a narrow distribution, foreign matter is not generated on the pattern after development, and the pattern shape is not deteriorated.

[0117] The polymer can be synthesized, for example, by polymerizing a monomer that provides the repeating unit described above in an organic solvent with the addition of a radical polymerization initiator by heating.

[0118] Examples of organic solvents used during polymerization include toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), and γ-butyrolactone (GBL). Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, and lauroyl peroxide. The amount of these initiators added is preferably 0.01 to 25 mol% based on the total amount of monomers to be polymerized. The reaction temperature is preferably 50 to 150°C, and more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours, and more preferably 2 to 12 hours from the viewpoint of production efficiency.

[0119] The polymerization initiator may be added to the monomer solution and then fed to the reaction vessel. Alternatively, an initiator solution may be prepared separately from the monomer solution and then fed to the reaction vessel independently. Because radicals generated from the initiator during the waiting time may cause the polymerization reaction to proceed, resulting in the formation of ultra-high molecular weight polymers, it is preferable to prepare the monomer solution and the initiator solution independently and add them dropwise from the perspective of quality control. The acid labile group introduced into the monomer may be used as is, or may be protected or partially protected after polymerization. Furthermore, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol may be used in combination to adjust the molecular weight. The amount of the chain transfer agent added is preferably 0.01 to 20 mol % of the total amount of monomers to be polymerized.

[0120] In the case of a monomer containing a hydroxy group, the hydroxy group may be substituted with an acetal group, such as an ethoxyethoxy group, which is easily deprotected by an acid, during polymerization, and then deprotected with a weak acid and water after polymerization. Alternatively, the hydroxy group may be substituted with an acetyl group, a formyl group, a pivaloyl group, or the like, and then subjected to alkaline hydrolysis after polymerization.

[0121] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene and other monomers may be polymerized by heating in an organic solvent with the addition of a radical polymerization initiator. Alternatively, acetoxystyrene or acetoxyvinylnaphthalene may be used, and after polymerization, the acetoxy group may be deprotected by alkaline hydrolysis to form polyhydroxystyrene or hydroxypolyvinylnaphthalene.

[0122] Specific examples of the base that can be used in alkaline hydrolysis include aqueous ammonia, triethylamine, etc. The reaction temperature is preferably −20 to 100° C., more preferably 0 to 60° C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0123] The amount of each monomer in the monomer solution may be appropriately set so as to achieve the preferred content ratio of the repeating units described above.

[0124] The polymer obtained by the above-described production method may be a reaction solution obtained by a polymerization reaction as a final product, or a powder obtained through a purification step such as a reprecipitation method in which a polymerization solution is added to a poor solvent to obtain a powder, and the resulting powder may be handled as a final product. However, from the viewpoint of work efficiency and quality stability, it is preferable to handle a polymer solution obtained by dissolving the powder obtained through the purification step in a solvent as a final product.

[0125] Specific examples of the solvent used in this case include ketones such as cyclohexanone and methyl-2-n-pentyl ketone, as described in paragraphs

[0144] to

[0145] of JP-A No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether. esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono tert-butyl ether acetate; lactones such as GBL; alcohols such as diacetone alcohol (DAA); high-boiling alcohol solvents such as diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, and 1,3-butanediol; and mixed solvents thereof.

[0126] The concentration of the polymer in the polymer solution is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass.

[0127] The reaction solution and polymer solution are preferably filtered through a filter, which is effective in stabilizing quality by removing foreign matter and gels that may cause defects.

[0128] Examples of filter materials used in the filter filtration include fluorocarbon, cellulose, nylon, polyester, and hydrocarbon-based materials. However, in the filtration process for chemically amplified resist compositions, filters made of fluorocarbons, such as Teflon (registered trademark), hydrocarbons such as polyethylene and polypropylene, or nylon are preferred. The pore size of the filter can be selected appropriately depending on the desired cleanliness, but is preferably 100 nm or less, more preferably 20 nm or less. These filters may be used alone or in combination. The filtration method may involve passing the solution through the filter only once, but it is more preferable to circulate the solution and filter it multiple times. The filtration process can be performed in any order and any number of times during the polymer production process. However, it is preferable to filter the reaction solution after the polymerization reaction, the polymer solution, or both.

[0129] [Chemically amplified negative resist composition] [(A) Base polymer] The chemically amplified resist composition of the present invention contains, as component (A), a base polymer containing the above-mentioned polymer.

[0130] The base polymer may be used alone or in combination with two or more types differing in composition ratio, Mw, and / or Mw / Mn. When two or more types are combined, a polymer containing the repeating unit A1 and a polymer not containing the repeating unit A1 but containing any of the repeating units A2, A3, A4, A5, and A6 may be used. In this case, the content of the polymer not containing the repeating unit A1 is preferably 2 to 5,000 parts by mass, more preferably 10 to 1,000 parts by mass, per 100 parts by mass of the polymer containing the repeating unit A1.

[0131] In this case, the base polymer not containing the repeating unit A1 is preferably one containing a repeating unit represented by the following formula (A2-1) and a repeating unit represented by the following formula (A3-1) or (A3-2). [ka] (In the formula, a3, a4, b4, R A , R B , Y 2 , R 11 , R 13 , R 14 is the same as above.)

[0132] From the viewpoint of etching resistance, the base polymer preferably contains repeating units having an aromatic ring skeleton in an amount of 60 mol% or more, more preferably 80 mol% or more, of all repeating units of the polymer contained in the base polymer, and even more preferably all repeating units have an aromatic ring skeleton.

[0133] [(B) Quencher] The chemically amplified negative resist composition of the present invention preferably contains a quencher (acid diffusion inhibitor) as component (B). In the present invention, a quencher is a material that traps the acid generated by the photoacid generator in the chemically amplified resist composition, thereby preventing it from diffusing into unexposed areas and allowing the formation of a desired pattern.

[0134] Examples of the quencher include conventional basic compounds. Examples of conventional basic compounds include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxy group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, and carbamates. In particular, the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP 2008-111103 A are preferred, including amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate ester bond, and compounds having a carbamate group described in JP 3790649 A. Preferred examples include tris[2-(methoxymethoxy)ethyl]amine, tris[2-(methoxymethoxy)ethyl]amine-N-oxide, dibutylaminobenzoic acid, morpholine derivatives, imidazole derivatives, etc. Addition of such basic compounds can, for example, further suppress the diffusion rate of acid in the resist film or correct the shape.

[0135] The quencher is preferably one represented by the following formula (B1): [ka]

[0136] In formula (B1), R 101 , R 102 and R 103are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0]. 2,6 ] cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as a decyl group, an adamantyl group, or an adamantylmethyl group; and aryl groups having 6 to 20 carbon atoms, such as a phenyl group, a naphthyl group, or an anthracenyl group. Some of the hydrogen atoms in the hydrocarbyl groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, or halogen atoms, and some of the -CH2- groups in the hydrocarbyl groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, or nitrogen atoms, so that the hydrocarbyl groups may contain hydroxy groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, thioether bonds, ester bonds, sulfonate ester bonds, carbonate bonds, carbamate bonds, lactone rings, sultone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, or the like.

[0137] In formula (B1), k1 and k2 each independently represent an integer of 0 to 5. k3 represents an integer of 0 to 4. From the viewpoints of ease of synthesis and availability of raw materials, k1, k2, and k3 are each preferably 0, 1, or 2.

[0138] When k1 is 2 to 5, two adjacent R 101 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. When k2 is 2 to 5, two adjacent R 102may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. When k3 is 2 to 4, two adjacent R 103 may be bonded to each other to form a ring together with the carbon atoms to which they are attached.

[0139] Examples of the betaine type compound represented by formula (B1) include, but are not limited to, the compounds shown below. [ka]

[0140] The betaine-type compound has a counter anion of a strongly basic phenoxide, which provides excellent acid diffusion control and improved contrast. Furthermore, since salt exchange with the sulfonium salt contained in the repeating unit A1 does not occur in the resist composition, the solvent solubility of the base polymer containing the repeating unit A1 is maintained, allowing a resist composition to be obtained without the formation of aggregates. Furthermore, the compound effectively reduces post-development and post-etching defects after resist patterning, making it difficult for aggregate defects to occur even in fine patterns. This allows for the provision of a next-generation resist composition that combines high resolution with excellent defect suppression.

[0141] Alternatively, a weak acid betaine compound may be used as the quencher. Specific examples thereof include, but are not limited to, the following: [ka]

[0142] Further, examples of the quencher include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of carboxylic acids not fluorinated at the α-position, as described in JP-A-2008-158339. Sulfonic acids, imide acids, or methide acids fluorinated at the α-position are necessary for deprotecting acid labile groups, and salt exchange with onium salts not fluorinated at the α-position releases carboxylic acids not fluorinated at the α-position. Carboxylic acids not fluorinated at the α-position hardly undergo deprotection reactions, and therefore function as quenchers.

[0143] Examples of onium salts of carboxylic acids that are not fluorinated at the α-position include those represented by the following formula (B2). [ka]

[0144] In formula (B2), R 111 represents a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hydrogen atom or a heteroatom, but excludes those in which the hydrogen atom bonded to the carbon atom at the α-position of the carboxy group is substituted with a fluorine atom or a fluoroalkyl group.

[0145] R 111 The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 40 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, and a tricyclo[5.2.1.0] 2,6]Cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms such as a decyl group, an adamantyl group, and an adamantylmethyl group; alkenyl groups having 2 to 40 carbon atoms such as a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 40 carbon atoms such as a cyclohexenyl group; phenyl group, naphthyl group, alkylphenyl groups (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, Examples of aryl groups include aryl groups having 6 to 40 carbon atoms such as arylphenyl groups (e.g., 2,4-n-butylphenyl group, 4-n-butylphenyl group), di- or trialkylphenyl groups (e.g., 2,4-dimethylphenyl group, 2,4,6-triisopropylphenyl group), alkylnaphthyl groups (e.g., methylnaphthyl group, ethylnaphthyl group), and dialkylnaphthyl groups (e.g., dimethylnaphthyl group, diethylnaphthyl group); and aralkyl groups having 7 to 40 carbon atoms such as benzyl group, 1-phenylethyl group, and 2-phenylethyl group.

[0146] Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like. Examples of the hydrocarbyl group containing a heteroatom include heteroaryl groups such as a thienyl group; alkoxyphenyl groups such as a 4-hydroxyphenyl group, a 4-methoxyphenyl group, a 3-methoxyphenyl group, a 2-methoxyphenyl group, a 4-ethoxyphenyl group, a 4-tert-butoxyphenyl group, and a 3-tert-butoxyphenyl group; alkoxynaphthyl groups such as a methoxynaphthyl group, an ethoxynaphthyl group, an n-propoxynaphthyl group, and an n-butoxynaphthyl group; dialkoxynaphthyl groups such as a dimethoxynaphthyl group and a diethoxynaphthyl group; and aryloxoalkyl groups such as a 2-aryl-2-oxoethyl group, a 2-(1-naphthyl)-2-oxoethyl group, and a 2-(2-naphthyl)-2-oxoethyl group.

[0147] In formula (B2), Mq A + is an onium cation. The onium cation is preferably a sulfonium cation, an iodonium cation, or an ammonium cation, and more preferably a sulfonium cation or an iodonium cation. Preferred examples of the compound include those described in paragraphs

[0154] to

[0182] of JP-A No. 2023-091749, and more preferably a cation of a sulfonium salt represented by formula (A1).

[0148] Examples of the anion of the onium salt represented by formula (B2) include, but are not limited to, those shown below. [ka]

[0149] [ka]

[0150] [ka]

[0151] As the quencher, a sulfonium salt of an iodinated benzene ring-containing carboxylic acid represented by the following formula (B3) can also be suitably used. [ka]

[0152] In formula (B3), k11 is an integer of 1 to 5. k12 is an integer of 0 to 3. k13 is an integer of 1 to 3.

[0153] In formula (B3), R 121 is a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may contain a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may contain a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms which may contain a halogen atom, a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms which may contain a halogen atom, or —N(R 121A )-C(=O)-R 121B or -N(R 121A )-C(=O)-OR 121B R 121A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 121B is a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms. When k11 and / or k13 is 2 or more, each R 121 may be the same or different from each other.

[0154] In formula (B3), L 1 is a single bond or a (k13+1)-valent linking group having 1 to 20 carbon atoms, and may contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxy group, and a carboxy group. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, and saturated hydrocarbylsulfonyloxy group may be linear, branched, or cyclic.

[0155] In formula (B3), R 122 , R 123 and R 124 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples thereof include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms. Some or all of the hydrogen atoms in the hydrocarbyl group may be substituted with a hydroxy group, a carboxy group, a halogen atom, an oxo group, a cyano group, a nitro group, a sultone ring, a sulfo group, or a sulfonium salt-containing group, and some of the -CH2- groups in the hydrocarbyl group may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond, or a sulfonate ester bond. In addition, R 122 and R 123 However, they may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. Specific structures of the sulfonium cation of the sulfonium salt represented by formula (B3) include those described in paragraphs

[0154] to

[0180] of JP-A No. 2023-091749, but the cation of the sulfonium salt represented by formula (A1) is preferred.

[0156] Specific examples of the compound represented by formula (B3) include those described in JP 2017-219836 A. The compound represented by formula (B3) has high absorption, a high sensitizing effect, and a high acid diffusion suppressing effect.

[0157] As the quencher, a nitrogen atom-containing carboxylate compound represented by the following formula (B4) can also be used. [ka]

[0158] In formula (B4), R 131 ~R 134 are each independently a hydrogen atom, -L 2 -CO2 - or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. 131 and R 132 and R 132 and R 133 and, or R 133 and R 134 and may be bonded to each other to form a ring together with the carbon atoms to which they are attached. 2 R is a single bond or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 135 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hydrogen atom or a heteroatom.

[0159] In formula (B4), ring R r is a ring containing carbon atoms and nitrogen atoms and having 2 to 6 carbon atoms, and some or all of the hydrogen atoms bonded to the carbon atoms of the ring are hydrocarbyl groups having 1 to 20 carbon atoms, or -L 2 -CO2 -and some of the carbon atoms of the ring may be substituted with sulfur atoms, oxygen atoms, or nitrogen atoms. The ring may be an alicyclic ring or an aromatic ring, and is preferably a 5- or 6-membered ring, specific examples of which include a pyridine ring, a pyrrole ring, a pyrrolidine ring, a piperidine ring, a pyrazole ring, an imidazoline ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, an imidazoline ring, an oxazole ring, a thiazole ring, a morpholine ring, a thiazine ring, and a triazole ring.

[0160] The onium carboxylic acid salt represented by formula (B4) has at least one -L 2 -CO2 - group, i.e., R 131 ~R 134 At least one of the -L 2 -CO2 - and / or at least one of the hydrogen atoms bonded to the carbon atom of the ring R is -L 2 -CO2 - is replaced by

[0161] In formula (B4), Mq B + is a sulfonium cation, an iodonium cation, or an ammonium cation, preferably a sulfonium cation. Specific examples of the sulfonium cation include those described in paragraphs

[0154] to

[0180] of JP-A No. 2023-091749, and preferably a cation of a sulfonium salt represented by formula (A1).

[0162] Examples of the anion of the compound represented by formula (B4) include, but are not limited to, those shown below. [ka]

[0163] [ka]

[0164] [ka]

[0165] [ka]

[0166] [ka]

[0167] [ka]

[0168] Further examples of the quencher include the polymer-type quencher described in JP 2008-239918 A. This quencher enhances the rectangularity of the resist pattern by orienting on the surface of the resist film. The polymer-type quencher also has the effect of preventing pattern film loss and pattern top rounding when a protective film for immersion lithography is applied.

[0169] When the chemically amplified negative resist composition of the present invention contains a (B) quencher, the content thereof is preferably 0.01 to 50 parts by mass, more preferably 0.1 to 30 parts by mass, relative to 80 parts by mass of the (A) base polymer. To suppress acid diffusion, a pattern with excellent resolution and LER can be formed by using preferably 5 parts by mass or more, more preferably 7 parts by mass or more, and even more preferably 10 parts by mass or more, relative to 80 parts by mass of the (A) base polymer. It is particularly preferable to use a quencher having a betaine or sulfonium salt structure. The (B) quencher may be used alone or in combination of two or more types.

[0170] [(C) Photoacid generator] The chemically amplified negative resist composition of the present invention may contain a photoacid generator as component (C). The photoacid generator is not particularly limited as long as it is a compound that generates an acid upon exposure to high-energy rays. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate-type acid generators.

[0171] Specific examples of the photoacid generator include nonafluorobutanesulfonate, the partially fluorinated sulfonates described in paragraphs

[0247] to

[0251] of JP 2012-189977 A, the partially fluorinated sulfonates described in paragraphs

[0261] to

[0265] of JP 2013-101271 A, those described in paragraphs

[0122] to

[0142] of JP 2008-111103 A, and paragraphs

[0080] to

[0081] of JP 2010-215608 A, and fluorobenzenesulfonic acid type. Among these specific examples, arylsulfonate-type or alkane sulfonate-type photoacid generators are preferred because they generate an acid of suitable strength for deprotecting the acid labile group in the repeating unit represented by formula (A5).

[0172] As such a photoacid generator, an onium salt compound having an anion of the structure shown below is preferred. [ka]

[0173] [ka]

[0174] [ka]

[0175] [ka]

[0176] [ka]

[0177] [ka]

[0178] [ka]

[0179] [ka]

[0180] [ka]

[0181] As the photoacid generator of the component (C), an onium salt compound containing an anion represented by the following formula (C-1) is also preferred. [ka]

[0182] In formula (C-1), m1 and m2 each independently represent an integer of 0 to 2. When m1 is 0, it represents a benzene ring, when m1 is 1 it represents a naphthalene ring, and when m1 is 2 it represents an anthracene ring, but from the viewpoint of solvent solubility, m1 is preferably a benzene ring of 0. Also, from the viewpoint of solvent solubility, m2 is preferably 0.

[0183] In formula (C-1), m3 is an integer of 1 to 5 when m1 is 0, an integer of 1 to 7 when m1 is 1, and an integer of 1 to 9 when m1 is 2. m4 is an integer of 0 to 5 when m2 is 0, an integer of 0 to 7 when m1 is 1, and an integer of 0 to 9 when m1 is 2.

[0184] In formula (C-1), L 11is a single bond, an ether bond, an ester bond, a sulfonate ester bond, an amide bond, a carbonate bond or a carbamate bond. Of these, an ether bond, an ester bond or a sulfonate ester bond is preferred, and a sulfonate ester bond is more preferred.

[0185] In formula (C-1), R 201 is an iodine atom or a branched or cyclic hydrocarbyl group having 3 to 20 carbon atoms which may contain a heteroatom, and at least one R 201 L 1 Specific examples of the hydrocarbyl group include an isopropyl group, a sec-butyl group, a tert-butyl group, a tert-pentyl group, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, an oxanorbornyl group, a tricyclo[5.2.1.0] group, a cyclopentylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, an oxanorbornyl group, a tricyclo[5.2.1.0] group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclohexylbutyl group, a norbornyl group, a cyclohexylmethyl group, a cyclohex ... 2,6 Examples of the hydrocarbyl group include, but are not limited to, aliphatic cyclic hydrocarbon groups having 3 to 20 carbon atoms, such as a decyl group or an adamantyl group; aryl groups, such as a phenyl group, a naphthyl group, or an anthracenyl group; and groups obtained by combining these. Furthermore, some or all of the hydrogen atoms in the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH2- groups in the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the hydrocarbyl group containing a hydroxy group, a cyano group, a halogen atom, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom or an iodine atom being preferred. When m3 is 2 or greater, each R 201 may be the same as or different from each other.

[0186] Also, when m3 is 2 or more, multiple R 201 However, they may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. The ring is preferably a 5- to 8-membered ring.

[0187] In formula (C-1), R 202 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0]. 2,6 ] cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as a decyl group, an adamantyl group, or an adamantylmethyl group; and aryl groups having 6 to 20 carbon atoms, such as a phenyl group, a naphthyl group, or an anthracenyl group. Furthermore, some or all of the hydrogen atoms in the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom. Alternatively, some of the -CH2- groups in the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, the hydrocarbyl group may contain a hydroxy group, a cyano group, a halogen atom, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. When m4 is 2 or greater, each R 202 may be the same as or different from each other.

[0188] Also, when m4 is 2 or more, multiple R202 However, they may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. The ring is preferably a 5- to 8-membered ring.

[0189] In formula (C-1), W 1 is the carbon atom C of the adjacent aromatic ring. 1 and C 2 and a part of the carbon atoms forming the ring may be substituted with a group containing a hetero atom. The ring may be monocyclic or polycyclic. 2 is the carbon atom C of the adjacent aromatic ring. 3 and C 4 and a part of the carbon atoms forming the ring may be substituted with a group containing a hetero atom. The ring may be monocyclic or polycyclic.

[0190] W in formula (C-1) 1 and W 2 Examples of the structure in which an aromatic ring is fused with an adjacent aromatic ring include, but are not limited to, those shown below. In the following formula, the dashed line indicates L 1 It is a combination of. [ka]

[0191] R in formula (C-1) 201 Examples of the structure in which L is bonded to an aromatic ring include, but are not limited to, those shown below. In the following formula, the dashed line indicates L 11 It is a combination of. [ka]

[0192] [ka]

[0193] [ka]

[0194] [ka]

[0195] [ka]

[0196] [ka]

[0197] The anion represented by formula (C-1) is preferably an anion represented by the following formula (C-1-1). [ka] (In the formula, m2, m3, m4, L 11 , R 201 , R 202 , W 1 and W 2 is the same as above.)

[0198] The anion represented by formula (C-1-1) is preferably an anion represented by the following formula (C-1-2). [ka] (In the formula, m3, m4, R 201 , R 202 and W 1 is the same as above.)

[0199] Particularly preferred examples of the anion represented by formula (C-1) include, but are not limited to, those shown below. [ka]

[0200] [ka]

[0201]

change

[0202]

change

[0203]

change

[0204]

change

[0205]

change

[0206]

change

[0207]

change

[0208]

change

[0209]

change

[0210]

change

[0211]

change

[0212]

change

[0213]

change

[0214]

change

[0215]

change

[0216]

change

[0217]

change

[0218]

change

[0219]

change

[0220]

change

[0221]

change

[0222] [ka]

[0223] The onium salt containing the anion represented by formula (C-1) is an onium salt of a sulfonic acid not substituted with fluorine atoms, and therefore can generate an acid of appropriate strength upon irradiation with high-energy radiation. Furthermore, it has a structural feature in that it has a ring structure further condensed to the aromatic ring bonded to the sulfo group of the anion and another aromatic ring structure containing a bulky substituent. The steric hindrance between these two aromatic rings reduces the degree of rotational freedom of the bond connecting the aromatic rings, thereby limiting excessive acid diffusion of the generated acid. Furthermore, the onium salt of the present invention has sufficient liposolubility, making it easy to manufacture and handle. These effects enable the generation of an acid in a resist film with excessive acid strength and controlled acid diffusion, thereby enabling the formation of fine patterns with good resolution, small LER, and excellent rectangularity.

[0224] As the photoacid generator of the component (C), an onium salt compound containing an anion represented by the following formula (C-2) is also preferred. [ka]

[0225] In formula (C-2), m11 and m12 each independently represent an integer of 0 to 2. When m12 is 0, m13 represents an integer of 1 to 4, when m12 is 1, it represents an integer of 1 to 6, and when m12 is 2, it represents an integer of 1 to 8.

[0226] In formula (C-2), m14 is an integer of 0 to 3 when m12 is 0, an integer of 0 to 5 when m12 is 1, and an integer of 0 to 7 when m12 is 2. However, m13+m14 is 1 to 4 when m12 is 0, is 1 to 6 when m12 is 1, and is 1 to 8 when m12 is 2.

[0227] In formula (C-2), m15 is an integer of 1 to 5 when m11 is 0, an integer of 1 to 7 when m11 is 1, and an integer of 1 to 9 when m11 is 2.

[0228] In formula (C-2), R 211 are each independently an iodine atom or a branched or cyclic hydrocarbyl group having 3 to 20 carbon atoms which may contain a heteroatom, and at least one R 211 is the L 21 Specific examples of the hydrocarbyl group include branched alkyl groups such as an isopropyl group, a sec-butyl group, a tert-butyl group, a tert-pentyl group, and a 2-ethylhexyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, an oxanorbornyl group, and a tricyclo[5.2.1.0] group. 2,6 Examples of the hydrocarbyl group include, but are not limited to, cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as a decyl group or an adamantyl group; aryl groups, such as a phenyl group, a naphthyl group, or an anthracenyl group; and groups obtained by combining these. Furthermore, some or all of the hydrogen atoms in the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH2- groups in the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the hydrocarbyl group containing a hydroxy group, a cyano group, a halogen atom, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom or an iodine atom being preferred. When m15 is 2 or greater, each R 211 may be the same as or different from each other.

[0229] Also, when m15 is 2 or more, multiple R211 However, they may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. The ring is preferably a 5- to 8-membered ring.

[0230] R in formula (C-2) 211 Examples of the structure in which L is bonded to an aromatic ring include, but are not limited to, those shown below. In the following formula, the dashed line indicates L 21 It is a combination of. [ka]

[0231] [ka]

[0232] [ka]

[0233] [ka]

[0234] [ka]

[0235] [ka]

[0236] [ka]

[0237] In formula (C-2), R 202are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0]. 2,6 ] cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as a decyl group, an adamantyl group, or an adamantylmethyl group; and aryl groups having 6 to 20 carbon atoms, such as a phenyl group, a naphthyl group, or an anthracenyl group. Furthermore, some or all of the hydrogen atoms in the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom. Alternatively, some of the -CH2- groups in the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, the hydrocarbyl group may contain a hydroxy group, a cyano group, a halogen atom, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. When m14 is 2 or greater, each R 202 may be the same as or different from each other.

[0238] Also, when m14 is 2 or more, multiple R 202 However, they may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. The ring is preferably a 5- to 8-membered ring.

[0239] In formula (C-2), R F1R are each independently a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, or a fluorinated thioalkoxy group having 1 to 6 carbon atoms. F1 is preferably a fluorine atom, a trifluoromethyl group, a difluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group, a trifluoromethylthio group, or a difluoromethylthio group, and more preferably a fluorine atom, a trifluoromethyl group, or a trifluoromethoxy group. The inclusion of a fluorine atom improves the acid strength of the generated acid, allowing the deprotection reaction to proceed smoothly. When m13 is 2 or more, each R F1 may be the same as or different from each other.

[0240] In formula (C-2), L 21 and L 22 are each independently a single bond, an ether bond, an ester bond, an amide bond, a sulfonate ester bond, a carbonate bond, or a carbamate bond. Among these, an ether bond, an ester bond, or a sulfonate ester bond is preferred, and an ether bond or a sulfonate ester bond is more preferred.

[0241] In formula (C-2), X L is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include an alkanediyl group and a cyclic saturated hydrocarbylene group. Specific examples of the heteroatom include an oxygen atom, a nitrogen atom, and a sulfur atom.

[0242] X L Specific examples of the hydrocarbylene group having 1 to 40 carbon atoms and optionally containing a hetero atom, represented by the formula (I), include, but are not limited to, those shown below. In the formula (I), * represents L 21 and L 22 Represents a bond with . [ka]

[0243] [ka]

[0244] [ka]

[0245] [ka]

[0246] Of these, X L -0~X L -22 and X L -47~X L -58 is preferred.

[0247] The acid generator represented by formula (C-2) is preferably one represented by the following formula (C-2-1). [ka] (In the formula, m11~m15, R 211 , R 212 , R F1 , L 21 and X L is the same as above.)

[0248] Specific examples of the anion represented by formula (C-2) include, but are not limited to, those shown below. [ka]

[0249] [ka]

[0250] [ka]

[0251]

change

[0252]

change

[0253]

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[0254]

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[0255]

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[0256]

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[0257]

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[0258]

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[0259]

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[0260]

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[0261]

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[0262]

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[0263]

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[0264]

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[0265]

change

[0266]

change

[0267]

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[0268]

change

[0269]

change

[0270]

change

[0271]

change

[0272] [ka]

[0273] [ka]

[0274] [ka]

[0275] [ka]

[0276] [ka]

[0277] [ka]

[0278] [ka]

[0279] [ka]

[0280] Furthermore, as the photoacid generator of the component (C), an onium salt compound containing an anion represented by the following formula (C-3) is also preferred. [ka]

[0281] In formula (C-3), m21 is 1, 2 or 3. m22 is an integer of 1 to 5. m23 is an integer of 0 to 3. m24 is 0 or 1.

[0282] In formula (C-3), L 31 is a single bond, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond or a carbamate bond.

[0283] In formula (C-3), L 32 is an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond or a carbamate bond.

[0284] In formula (C-3), L 33 represents a single bond or a hydrocarbylene group having 1 to 20 carbon atoms when m21 is 1, and represents an (m21+1)-valent hydrocarbon group having 1 to 20 carbon atoms when m21 is 2 or 3, and the hydrocarbylene group and the (m21+1)-valent hydrocarbon group may contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxy group, and a carboxy group.

[0285] L 33 The hydrocarbylene group having 1 to 20 carbon atoms represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group, and a dodecane-1,12-diyl group. alkanediyl groups having 1 to 20 carbon atoms; cyclic saturated hydrocarbylene groups having 3 to 20 carbon atoms such as cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, and adamantanediyl group; unsaturated aliphatic hydrocarbylene groups having 2 to 20 carbon atoms such as vinylene group and propene-1,3-diyl group; arylene groups having 6 to 20 carbon atoms such as phenylene group and naphthylene group; and groups obtained by combining these. 23The (p+1)-valent hydrocarbon group having 1 to 20 carbon atoms, represented by the formula (1), may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include groups obtained by further removing one or two hydrogen atoms from the specific examples of the hydrocarbylene group having 1 to 20 carbon atoms described above.

[0286] In formula (C-3), Rf 1 and Rf 2 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that at least one is a fluorine atom or a trifluoromethyl group.

[0287] In formula (C-3), R 221 is a hydroxy group, a carboxy group, a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, -N(R 221A )(R 221B ), -N(R 221C )-C(=O)-R 221D or -N(R 221C )-C(=O)-OR 221D R 221A and R 221B are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 221C is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 221D is a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms.

[0288] R 221 , R 221A , R 221B and R 221CThe saturated hydrocarbyl group having 1 to 6 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl groups; and cyclic saturated hydrocarbyl groups having 3 to 6 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups. 221 Examples of the saturated hydrocarbyl moiety of the saturated hydrocarbyloxy group having 1 to 6 carbon atoms and represented by the formula (I) include the same as the specific examples of the saturated hydrocarbyl group described above, and R 221 Examples of the saturated hydrocarbyl moiety of the saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms represented by the formula include those having 1 to 5 carbon atoms among the specific examples of the saturated hydrocarbyl groups having 1 to 6 carbon atoms mentioned above.

[0289] R 221D The unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include alkenyl groups having 2 to 8 carbon atoms such as vinyl, propenyl, butenyl, and hexenyl groups; alkynyl groups having 2 to 8 carbon atoms such as ethynyl, propynyl, and butynyl groups; and cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 8 carbon atoms such as cyclohexenyl and norbornenyl groups.

[0290] In formula (C-3), R 222 represents a saturated hydrocarbylene group having 1 to 20 carbon atoms or an arylene group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms of the saturated hydrocarbylene group may be substituted with halogen atoms other than fluorine atoms, or some or all of the hydrogen atoms of the arylene group may be substituted with a substituent selected from a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a halogen atom, and a hydroxy group.

[0291] R 222The hydrocarbylene group having 1 to 20 carbon atoms represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. 33 Examples of the hydrocarbylene group having 1 to 20 carbon atoms represented by the following formula include the same as those exemplified above.

[0292] R 222 Specific examples of the arylene group having 6 to 20 carbon atoms represented by the formula (I) include a phenylene group, a naphthylene group, a phenanthrenediyl group, and an anthracenediyl group. The hydrocarbyl moiety of the saturated hydrocarbyl group having 1 to 20 carbon atoms and the hydrocarbyloxy group having 1 to 20 carbon atoms, which are substituents on the arylene group, may be linear, branched, or cyclic, and specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, heptadecyl group, octadecyl group, nonadecyl group, and icosyl group; and cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group, norbornyl group, and adamantyl group. Specific examples of the arylene group having 6 to 14 carbon atoms that is the substituent of the arylene group include a phenylene group, a naphthylene group, a phenanthrenediyl group, and an anthracenediyl group.

[0293] The anion represented by formula (C-3) is preferably an anion represented by the following formula (C-3-1). [ka]

[0294] In formula (C-3-1), m21, m22, m23, L 31 , L 33 and R 221 is the same as above. m25 is an integer of 1 to 4. R223 is a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, an aryl group having 6 to 14 carbon atoms, a halogen atom, or a hydroxy group. When m25 is 2, 3, or 4, each R 223 may be the same as or different from each other.

[0295] Examples of the anion represented by formula (C-3) include, but are not limited to, those shown below. [ka]

[0296] [ka]

[0297] [ka]

[0298] [ka]

[0299] [ka]

[0300] [ka]

[0301] [ka]

[0302] [ka]

[0303]

change

[0304]

change

[0305]

change

[0306]

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[0307]

change

[0308]

change

[0309]

change

[0310]

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[0311]

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[0312]

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[0313]

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[0314]

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[0315]

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[0316]

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[0317]

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[0318]

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[0319]

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[0320]

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[0321]

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[0322]

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[0323] The cation paired with the anion of the onium salt is an onium cation. The onium cation is preferably a sulfonium cation, an iodonium cation, or an ammonium cation, more preferably a sulfonium cation or an iodonium cation. Preferred examples include those described in paragraphs

[0154] to

[0182] of JP-A-2023-091749, and particularly preferred are sulfonium salt cations represented by formula (A1).

[0324] When the chemically amplified negative resist composition of the present invention contains both an acid generator (component (C)) and a quencher (component (B)), the content ratio of the photoacid generator to the quencher ((C) / (B)) is preferably less than 6 by mass, more preferably less than 4, even more preferably less than 2, and even more preferably less than 1. When the content ratio of the acid generator to the quencher in the chemically amplified negative resist composition is within the above range, acid diffusion can be sufficiently suppressed, and excellent resolution and dimensional uniformity can be obtained.

[0325] [(D) Crosslinking agent] When the (A) base polymer does not contain the repeating unit (A3), the chemically amplified negative resist composition of the present invention preferably contains a crosslinking agent as component (D). On the other hand, when the (A) base polymer contains the repeating unit (A3), it does not necessarily need to contain a crosslinking agent.

[0326] Specific examples of crosslinking agents that can be used in the present invention include epoxy compounds, melamine compounds, guanamine compounds, glycoluril compounds or urea compounds, isocyanate compounds, azide compounds, and compounds containing double bonds, such as alkenyloxy groups, all of which are substituted with at least one group selected from a methylol group, an alkoxymethyl group, and an acyloxymethyl group. These may be used as additives or may be introduced as pendant groups into polymer side chains. Compounds containing hydroxy groups may also be used as crosslinking agents.

[0327] Examples of the epoxy compound include tris(2,3-epoxypropyl)isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether.

[0328] Examples of the melamine compound include compounds in which 1 to 6 methylol groups are methoxymethylated, such as hexamethylol melamine, hexamethoxymethyl melamine, and hexamethylol melamine, and mixtures thereof; and compounds in which 1 to 6 methylol groups are acyloxymethylated, such as hexamethoxyethyl melamine, hexaacyloxymethyl melamine, and hexamethylol melamine, and mixtures thereof.

[0329] Examples of the guanamine compound include compounds in which 1 to 4 methylol groups are methoxymethylated, such as tetramethylolguanamine, tetramethoxymethylguanamine, and tetramethylolguanamine, and mixtures thereof; and compounds in which 1 to 4 methylol groups are acyloxymethylated, such as tetramethoxyethylguanamine, tetraacyloxyguanamine, and tetramethylolguanamine, and mixtures thereof.

[0330] Examples of the glycoluril compound include compounds in which 1 to 4 methylol groups are methoxymethylated, such as tetramethylol glycoluril, tetramethoxyglycoluril, tetramethoxymethyl glycoluril, and tetramethylol glycoluril, or mixtures thereof; and compounds in which 1 to 4 methylol groups are acyloxymethylated in tetramethylol glycoluril, or mixtures thereof.

[0331] Examples of the urea compound include tetramethylol urea, tetramethoxymethyl urea, compounds in which 1 to 4 methylol groups are methoxymethylated, such as tetramethylol urea, or mixtures thereof, and tetramethoxyethyl urea.

[0332] Examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate.

[0333] Examples of the azide compound include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

[0334] Examples of the compound containing an alkenyloxy group include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, and trimethylolpropane trivinyl ether.

[0335] When the chemically amplified negative resist composition of the present invention contains a crosslinking agent (D), the content thereof is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of the base polymer (A). Within this range, there is little risk of patterns being connected together and resolution being reduced. The crosslinking agents (D) may be used alone or in combination of two or more.

[0336] [(E) Fluorine atom-containing polymer] The chemically amplified negative resist composition of the present invention, for the purposes of achieving high contrast, suppressing acid chemical flare upon high-energy radiation irradiation, shielding acid from mixing from the antistatic coating during the process of applying an antistatic coating material onto the resist film, and suppressing unexpected and unnecessary pattern degradation, may comprise, as component (E), a fluorine-containing polymer that includes at least one selected from the group consisting of a repeating unit represented by formula (E1) below (hereinafter also referred to as repeating unit E1), a repeating unit represented by formula (E2) below (hereinafter also referred to as repeating unit E2), a repeating unit represented by formula (E3) below (hereinafter also referred to as repeating unit E3), and a repeating unit represented by formula (E4) below (hereinafter also referred to as repeating unit E4), and that may further include at least one selected from the group consisting of a repeating unit represented by formula (E5) below (hereinafter also referred to as repeating unit E5) and a repeating unit represented by formula (E6) below (hereinafter also referred to as repeating unit E6). The fluorine atom-containing polymer also functions as a surfactant, and is therefore effective in preventing insoluble matter from re-adhering to the substrate during the development process, thereby preventing development defects. [ka]

[0337] In the formulas (E1) to (E6), x is an integer of 1 to 3. y is an integer that satisfies 0≦y≦5+2z−x. z is 0 or 1. h is an integer of 1 to 3. R B are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. C are each independently a hydrogen atom or a methyl group. 301 , R 302 , R 304 and R 305 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. 303 , R 306 , R 307 and R 308 are each independently a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or an acid labile group, and R303 , R 306 , R 307 and R 308 When R is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be present between the carbon-carbon bond. 309 R is a hydrogen atom or a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a heteroatom-containing group interposed between its carbon-carbon bond. 310 R is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms, which may have a heteroatom-containing group interposed between its carbon-carbon bond. 311 is a saturated hydrocarbyl group having 1 to 20 carbon atoms in which at least one hydrogen atom has been substituted with a fluorine atom, and some of the -CH2- groups in the saturated hydrocarbyl group may be substituted with an ester bond or an ether bond. 1 is a (g+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (g+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. 2 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * is a bond to a carbon atom in the main chain. Z 3 is a single bond, -O-, *-C(=O)-OZ 31 -Z 32 -or*-C(=O)-NH-Z 31 -Z 32 -It is. Z 31 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms. 32 is a single bond, an ester bond, an ether bond, or a sulfonamide bond. * is a bond to a carbon atom of the main chain.

[0338] In formulas (E1) and (E2), R 301 , R 302 , R 304 and R 305The saturated hydrocarbyl group having 1 to 10 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; and cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornyl. Of these, saturated hydrocarbyl groups having 1 to 6 carbon atoms are preferred.

[0339] In formulas (E1) to (E4), R 303 , R 306 , R 307 and R 308 The hydrocarbyl group having 1 to 15 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include an alkyl group having 1 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms, and an alkynyl group having 2 to 15 carbon atoms, with an alkyl group having 1 to 15 carbon atoms being preferred. Examples of the alkyl group include those mentioned above, as well as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, and n-pentadecyl. Examples of the fluorinated hydrocarbyl group include groups in which some or all of the hydrogen atoms bonded to carbon atoms in the hydrocarbyl group mentioned above have been substituted with fluorine atoms.

[0340] In formula (E4), Z 1 Examples of the (g+1)-valent hydrocarbon group having 1 to 20 carbon atoms and represented by the formula (I) include a group in which h hydrogen atoms have been further removed from an alkyl group having 1 to 20 carbon atoms or a cyclic saturated hydrocarbyl group having 3 to 20 carbon atoms. 1Examples of the (g+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms and represented by the formula (I) include groups in which at least one hydrogen atom of the aforementioned (g+1)-valent hydrocarbon group has been substituted with a fluorine atom.

[0341] Specific examples of the repeating units E1 to E4 include, but are not limited to, the following: B is the same as above. [ka]

[0342] [ka]

[0343] [ka]

[0344] In formula (E5), R 309 and R 310 Examples of the hydrocarbyl group having 1 to 5 carbon atoms represented by the formula (I) include an alkyl group, an alkenyl group, and an alkynyl group, with an alkyl group being preferred. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and an n-pentyl group. In addition, a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom may be present between the carbon-carbon bonds of the hydrocarbyl group.

[0345] In formula (E5), -OR 309 is preferably a hydrophilic group. 309 As the alkyl group, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms and an oxygen atom intervening between the carbon-carbon bonds, and the like are preferred.

[0346] In formula (E5), Z 2 is preferably *-C(=O)-O- or *-C(=O)-NH-. Dis preferably a methyl group. 2 The presence of a carbonyl group in R improves the acid trapping ability of the antistatic film. D When the methyl group is used, the polymer becomes more rigid with a higher glass transition temperature (Tg), which suppresses acid diffusion, resulting in good stability of the resist film over time and preventing degradation of resolution and pattern shape.

[0347] Examples of the repeating unit E5 include, but are not limited to, those shown below. C is the same as above. [ka]

[0348] [ka]

[0349] In formula (E6), Z 3 The saturated hydrocarbylene group having 1 to 10 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-1,3-diyl group, a propane-2,2-diyl group, a butane-1,1-diyl group, a butane-1,2-diyl group, a butane-1,3-diyl group, a butane-2,3-diyl group, a butane-1,4-diyl group, and a 1,1-dimethylethane-1,2-diyl group.

[0350] In formula (E6), R 111 The saturated hydrocarbyl group having 1 to 20 carbon atoms, represented by the formula (I) above, in which at least one hydrogen atom has been substituted with a fluorine atom, may be linear, branched, or cyclic, and specific examples thereof include an alkyl group having 1 to 20 carbon atoms or a cyclic saturated hydrocarbyl group having 3 to 20 carbon atoms in which at least one hydrogen atom has been substituted with a fluorine atom.

[0351] Examples of the repeating unit E6 include, but are not limited to, those shown below. C is the same as above. [ka]

[0352] [ka]

[0353] [ka]

[0354] [ka]

[0355] The content of repeating units E1 to E4 is preferably 15 to 95 mol %, more preferably 20 to 85 mol %, of all repeating units in the fluorine atom-containing polymer. The content of repeating units E5 and / or E6 is preferably 5 to 85 mol %, more preferably 15 to 80 mol %, of all repeating units in the fluorine atom-containing polymer. The repeating units E1 to E6 may be used alone or in combination of two or more.

[0356] The fluorine atom-containing polymer may contain repeating units other than the repeating units described above. Examples of such repeating units include those described in paragraphs

[0046] to

[0078] of JP 2014-177407 A. When the fluorine atom-containing polymer contains other repeating units, the content of such other repeating units is preferably 50 mol % or less of all repeating units of the fluorine atom-containing polymer.

[0357] The fluorine atom-containing polymer can be synthesized by copolymerizing each monomer, optionally protected with a protecting group, according to a known method, followed by a deprotection reaction as needed. The copolymerization reaction is not particularly limited, but is preferably radical polymerization or anionic polymerization. For these methods, reference can be made to JP 2004-115630 A.

[0358] The Mw of the fluorine atom-containing polymer is preferably 2000 to 50000, more preferably 3000 to 20000. If the Mw is less than 2000, the diffusion of the acid is promoted, which may result in a deterioration in resolution and a loss of stability over time. If the Mw is too large, the solubility in the solvent decreases, which may cause coating defects. Furthermore, the fluorine atom-containing polymer preferably has an Mw / Mn ratio of 1.0 to 2.2, more preferably 1.0 to 1.7.

[0359] When the chemically amplified negative resist composition of the present invention contains (E) a fluorine atom-containing polymer, the content thereof is preferably 0.01 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and even more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of (A) base polymer. The (E) fluorine atom-containing polymer may be used alone, or two or more types may be used in combination.

[0360] [(F) Organic solvent] The chemically amplified negative resist composition of the present invention may contain an organic solvent as component (F). The organic solvent is not particularly limited as long as it is capable of dissolving each component. Examples of such organic solvents include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, as described in paragraphs

[0144] and

[0145] of JP-A No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, and ethylene glycol monoethyl ether. Examples of suitable solvents include ethers such as ethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, ethyl lactate (EL), ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as γ-butyrolactone; and mixed solvents thereof. When an acetal-based acid labile group is used, a high-boiling alcohol solvent, specifically, diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, 1,3-butanediol, or diacetone alcohol may be added to accelerate the deprotection reaction of the acetal.

[0361] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, PGME, cyclohexanone, EL, γ-butyrolactone, diacetone alcohol, and mixed solvents thereof are preferred.

[0362] When the chemically amplified negative resist composition of the present invention contains an organic solvent (F), the content thereof is preferably 200 to 10,000 parts by mass, and more preferably 400 to 5,000 parts by mass, relative to 80 parts by mass of the base polymer (A). The organic solvent (F) may be used alone or in combination of two or more types.

[0363] [(G) Surfactant] The chemically amplified negative resist composition of the present invention may contain a commonly used surfactant to improve its coatability onto a substrate. Many surfactants are known, as described in JP-A-2004-115630, and surfactants can be selected with reference to these. When the chemically amplified negative resist composition of the present invention contains a surfactant (G), the content thereof is preferably 0 to 5 parts by mass per 80 parts by mass of the base polymer (A). The surfactant (G) may be used alone, or two or more types may be used in combination.

[0364] [Method for forming resist pattern] The method for forming a resist pattern of the present invention includes the steps of: forming a resist film on a substrate using the aforementioned chemically amplified negative resist composition; irradiating the resist film with a pattern using high-energy rays (i.e., exposing the resist film using high-energy rays); and developing the resist film irradiated with the pattern using an alkaline developer.

[0365] The substrate may be, for example, a substrate for manufacturing integrated circuits (Si, SiO, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective coating, etc.), or a substrate for manufacturing transmission or reflection mask circuits (Cr, CrO, CrON, MoSi2, Si, SiO, SiO2, SiON, SiONC, CoTa, NiTa, TaBN, SnO2, etc.). The chemically amplified negative resist composition is applied to the substrate by a method such as spin coating to a film thickness of 0.03 to 2 μm, and the composition is pre-baked on a hot plate preferably at 60 to 150°C for 1 to 20 minutes, more preferably at 80 to 140°C for 1 to 10 minutes, to form a resist film.

[0366] Next, the resist film is exposed to high-energy rays to form a pattern. Examples of the high-energy rays include ultraviolet rays, far ultraviolet rays, excimer laser light (KrF, ArF, etc.), EUV, X-rays, gamma rays, synchrotron radiation, and EB. In the present invention, exposure using EUV or EB is preferred.

[0367] When ultraviolet rays, far ultraviolet rays, excimer laser light, EUV, X-rays, gamma rays, or synchrotron radiation is used as the high-energy rays, a mask for forming a desired pattern is used, and the exposure dose is preferably 1 to 500 mJ / cm. 2 , more preferably 10 to 400 mJ / cm 2 When EB is used, the exposure dose is preferably 1 to 500 μC / cm 2 directly to form the desired pattern. 2 , more preferably 10 to 450 μC / cm 2 , and more preferably 100 to 400 μC / cm 2 , and most preferably 150 to 400 μC / cm 2 Irradiate so that

[0368] The exposure may be performed by a conventional exposure method or, in some cases, by an immersion method in which the space between the mask and the resist film is immersed in liquid. In this case, a water-insoluble protective film may be used.

[0369] Next, post-exposure baking (PEB) is carried out on a hot plate, preferably at 60 to 150° C. for 1 to 20 minutes, more preferably at 80 to 140° C. for 1 to 10 minutes.

[0370] Thereafter, the substrate is developed using a developer such as an aqueous alkaline solution of 0.1 to 5 mass %, preferably 2 to 3 mass %, tetramethylammonium hydroxide (TMAH) or the like, preferably for 0.1 to 3 minutes, more preferably for 0.5 to 2 minutes, by a conventional method such as dipping, puddling, or spraying, to form a desired pattern on the substrate.

[0371] The chemically amplified negative resist composition of the present invention is particularly useful because it can form patterns with good resolution and small LER, and its optimal acid strength can suppress chemical flare during energy irradiation, which is expected to reduce development defects. Furthermore, the chemically amplified negative resist composition of the present invention is particularly useful for pattern formation on substrates having a surface made of a material that is prone to pattern peeling or pattern collapse, making it difficult to achieve adhesion of the resist pattern. Examples of such substrates include substrates having a sputtering film formed on the outermost surface by a film of metallic chromium or a chromium compound containing one or more light elements selected from oxygen, nitrogen, and carbon, SiO , SiO x Examples of the chemically amplified negative resist composition include a substrate containing, as an outermost layer, a tantalum compound, a molybdenum compound, a cobalt compound, a nickel compound, a tungsten compound, or a tin compound. The chemically amplified negative resist composition of the present invention is particularly useful for pattern formation using a photomask blank as the substrate. In this case, the photomask blank may be either a transmissive or reflective type.

[0372] As a transmission mask blank, a photomask blank having a light-shielding film made of a chromium-based material may be a photomask blank for a binary mask or a photomask blank for a phase shift mask. In the case of a photomask blank for a binary mask, the light-shielding film may have an antireflection layer and a light-shielding layer made of a chromium-based material, or the entire antireflection film on the surface layer side or only the layer further above the antireflection film on the surface layer side may be made of a chromium-based material, with the remaining portion being made of a silicon-based compound material that may contain, for example, a transition metal. In addition, in the case of a photomask blank for a phase shift mask, the target photomask blank may be a photomask blank for a phase shift mask having a chromium-based light-shielding film on a phase shift film.

[0373] The above-mentioned photomask blank having a chromium-based material in the outermost layer is very well known, as is disclosed in JP-A Nos. 2008-26500 and 2007-302873, or as examples of prior art therein. Therefore, detailed description will be omitted. However, for example, when a light-shielding film having an antireflection layer and a light-shielding layer is formed using a chromium-based material, the following film configuration can be used.

[0374] When a light-shielding film having an anti-reflection layer and a light-shielding layer is formed using a chromium-based material, the layer structure may be such that the anti-reflection layer and the light-shielding layer are laminated in this order from the surface side, or the anti-reflection layer, the light-shielding layer, and the anti-reflection layer are laminated in this order. The anti-reflection layer and the light-shielding layer may each be multi-layered, and the composition between layers with different compositions may change discontinuously or continuously. The chromium-based material used includes metallic chromium and metallic chromium containing light elements such as oxygen, nitrogen, and carbon. Specifically, metallic chromium, chromium oxide, chromium nitride, chromium carbide, chromium oxide nitride, chromium carbide oxide, chromium nitride carbonitride, chromium oxynitride carbonitride, etc. may be used.

[0375] A reflective mask blank includes a substrate, a multilayer reflective film formed on one main surface (front surface) of the substrate, specifically a multilayer reflective film that reflects exposure light such as EUV light, and an absorber film formed on the multilayer reflective film, specifically an absorber film that absorbs exposure light such as EUV light and reduces reflectance. From the reflective mask blank (EUV reflective mask blank), a reflective mask (EUV reflective mask) having an absorber pattern (absorber film pattern) formed by patterning the absorber film is manufactured. The wavelength of EUV light used in EUV lithography is 13 to 14 nm, and is typically light with a wavelength of about 13.5 nm.

[0376] Although the multilayer reflective film is preferably provided in contact with one main surface of the substrate, a base film may be provided between the substrate and the multilayer reflective film as long as the effects of the present invention are not lost. The absorber film may be formed in contact with the multilayer reflective film, but a protective film (protective film for the multilayer reflective film) may be provided between the multilayer reflective film and the absorber film, preferably in contact with the multilayer reflective film, and more preferably in contact with both the multilayer reflective film and the absorber film. The protective film is used to protect the multilayer reflective film during processing such as cleaning and repair. Furthermore, the protective film preferably has the function of protecting the multilayer reflective film when the absorber film is patterned by etching and preventing oxidation of the multilayer reflective film. Meanwhile, a conductive film used for electrostatically chucking the reflective mask to an exposure device may be provided under the other main surface (back surface) of the substrate, which is the surface opposite to the one main surface, preferably in contact with the other main surface. Here, one main surface of the substrate is the front surface and the upper side, and the other main surface is the back surface and the lower side, but the front and back and top and bottom of both are defined for convenience, and the one main surface and the other main surface are either of the two main surfaces (film formation surfaces) of the substrate, and the front and back and top and bottom are interchangeable. More specifically, it can be formed by a method such as that described in JP 2021-139970 A or exemplified as prior art therein.

[0377] According to the method for forming a resist pattern of the present invention, even when a substrate (for example, a transmission type or a reflection type mask blank) whose outermost surface is made of a material that is likely to affect the shape of the resist pattern, such as a material containing chromium, silicon, or tantalum, is used, it is possible to obtain a pattern that has extremely high resolution, small LER, excellent rectangularity, and excellent pattern fidelity. [Example]

[0378] The present invention will be specifically explained below with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples. The copolymerization composition ratios are molar ratios, and Mw is a polystyrene-equivalent measurement value obtained by GPC. The following apparatuses were used. IR: Thermo Fisher Scientific NICOLET 6700 · 1 H-NMR: ECA-500 manufactured by JEOL Ltd. MALDI TOF-MS: JEOL S3000

[0379] [1] Synthesis of onium salt monomers [Synthesis Example 1] Synthesis of Monomer PM-1 (1) Synthesis of intermediate In-1 [ka]

[0380] A Grignard reagent was prepared from magnesium (109.4 g), THF (2250 g), and raw material M-1 (1084.6 g) under a nitrogen atmosphere. The reaction system was cooled to below 10°C, and a solution consisting of diphenyl sulfoxide (303.4 g) and methylene chloride (1500 g) was added. After the addition, chlorotrimethylsilane (678.2 g) was added dropwise while maintaining the internal temperature below 20°C. The mixture was then aged for 2 hours at an internal temperature below 20°C. After aging, the reaction system was cooled, and an aqueous solution consisting of 36% by mass hydrochloric acid (150 g) and water (2250 g) was added dropwise to terminate the reaction. Diisopropyl ether (2100 g) and water (4500 g) were then added, and the aqueous layer was separated and collected. The separated aqueous layer was then washed twice with diisopropyl ether (1950 g). The washed aqueous layer was used directly in the next step.

[0381] (2) Synthesis of PM-1 [ka]

[0382] Under a nitrogen atmosphere, an aqueous solution of intermediate In-1 (537.0 g), intermediate In-2 (45.3 g), and methylene chloride (300 g) were added and stirred at room temperature for 30 minutes. The organic layer was separated, washed with water, and then concentrated under reduced pressure to give PM-1 as an oil (yield: 95.2 g, 90%).

[0383] The IR spectrum data and TOF-MS results of the monomer PM-1 are shown below. 1 The results of H-NMR / DMSO-d6) are shown in Figure 1. IR(D-ATR): ν= 3456, 3058, 1629, 1584, 1492, 1478, 1447, 1398, 1258, 1213, 1121, 1107, 1070, 1033, 1010, 924, 845, 809, 750, 733, 674, 581, 555, 530, 503cm -1 . MALDI TOF-MS: POSITIVE M + 347(C19 H 14 F3OS + equivalent) NEGATIVE M - 183(C8H7O3S - equivalent)

[0384] [2] Polymer synthesis [Example 1-1] Synthesis of Polymer P-1 Under a nitrogen atmosphere, a flask was charged with 70.4 g of 3-acetoxystyrene, 9.6 g of 4-chlorostyrene, 20.0 g of PM-1, 12.7 g of V-601 (Fujifilm Wako Pure Chemical Industries, Ltd.), and 120 g of PGME to prepare a monomer-polymerization initiator solution. 60 g of PGME was charged to a separate flask under a nitrogen atmosphere and heated to 80°C with stirring, followed by dropwise addition of the monomer-polymerization initiator solution over 4 hours. After completion of the dropwise addition, stirring was continued for 18 hours while maintaining the temperature of the polymerization solution at 80°C, and then the mixture was cooled to room temperature. The resulting polymerization solution was added dropwise to 5,000 g of a stirred MeOH / HO mixed solution, and the precipitated polymer was filtered off. The resulting polymer was washed twice with 1,000 g of the MeOH / HO mixed solution and then vacuum-dried at 40°C for 20 hours to obtain 86.4 g of polymer P-1 as a white powder. Polymer P-1 was then added dropwise to 5,000 g of a stirred MeOH / HO mixed solution. 13 C-NMR, 1 Measurements by H-NMR and GPC gave the following analytical results. Note that Mw is a polystyrene-equivalent measurement value obtained by GPC using DMF as a solvent. [ka]

[0385] [Examples 1-2 to 1-40, Synthesis Examples 2-1 to 2-7] Synthesis of Polymers P-2 to P-40 and Polymers AP-1 to AP-7 Polymers P-2 to P-40 and AP-1 to AP-7 shown in Tables 1 to 3 were synthesized in the same manner as in Example 1-1, except that the type and compounding ratio of each monomer was changed. In Tables 1 to 3, the introduction ratio indicates the molar ratio. Furthermore, the repeating units represented by PP-1 to PP-16 are expressed as polymer units of monomers synthesized in the same manner as in Synthesis Example 1.

[0386] [Table 1]

[0387] [Table 2]

[0388] [Table 3]

[0389] The structure of the repeating unit introduced into the polymer is shown below. [ka]

[0390] [ka]

[0391] [ka]

[0392] [ka]

[0393] [ka]

[0394] [ka]

[0395] The dissolution rates of the polymers in alkaline developers were calculated by spin-coating a polymer solution (polymer concentration: 12.0% by mass, solvent: PGME) onto an 8-inch silicon wafer, baking it at 150°C for 90 seconds to form a film with a thickness of 2000 nm, developing it in a 2.38% by mass aqueous TMAH solution at 23°C for 10 seconds, and measuring the amount of film loss. As a result, the dissolution rates of polymers P-1 to P-40 and AP-1 to AP-7 were 20 nm / sec or less.

[0396] [Comparative Examples 1-1 to 1-4] Synthesis of Polymers cP-1 to cP-4 Polymers cP-1 to cP-4 shown below were synthesized in the same manner as in Example 1-1, except that the raw material compounds used were changed. [ka]

[0397] The dissolution rates of the comparative polymers cP-1 to cP-4 were 20 nm / sec or less.

[0398] [2] Preparation of chemically amplified negative resist composition [Examples 2-1 to 2-76, Comparative Examples 2-1 to 2-7] Chemically amplified negative resist compositions were prepared by dissolving each component in an organic solvent according to the formulations shown in Tables 4 to 7 below, and filtering the resulting solution through a 5 nm nylon filter and a sub-1 nm UPE filter. The organic solvent was a mixed solvent of 920 parts by weight of PGMEA and 1850 parts by weight of EL, or 1850 parts by weight of diacetone alcohol and 1850 parts by weight of PGME. In Tables 4 to 7, the crosslinker TMGU is tetramethoxymethylglycoluril, and PF-636 is the surfactant PolyFox PF-636 manufactured by OMNOVA SOLUTIONS.

[0399] [Table 4]

[0400] [Table 5]

[0401] [Table 6]

[0402] [Table 7]

[0403] In Tables 4 to 7, the structures of quenchers Q-1 to Q-6, photoacid generators PAG-A to PAG-I, and polymers FP-1 to FP-5 are as follows: [ka]

[0404] [ka]

[0405] [ka]

[0406] [3] EB lithography evaluation [Examples 3-1 to 3-76, Comparative Examples 3-1 to 3-7] Each chemically amplified negative resist composition (R-1 to R-76, CR-1 to CR-7) was spin-coated using ACT-M (Tokyo Electron Ltd.) onto a 152 mm square reflective mask blank for EUV exposure masks, the outermost surface of which was a chromium compound, and the blank was pre-baked on a hot plate at 110°C for 600 seconds to produce an 80 nm thick resist film. The thickness of the resulting resist film was measured using an optical measuring device, Nanospec (Nanometrics). Measurements were taken at 81 locations on the surface of the blank substrate, excluding the outer edge extending 10 mm inward from the outer periphery of the blank, and the average film thickness and film thickness range were calculated.

[0407] The resist was then exposed using an electron beam exposure system (EBM-5000plus, manufactured by NuFlare Technology, Inc., accelerating voltage 50 kV), baked at 110°C for 600 seconds (PEB: post exposure bake), and developed in a 2.38% by mass aqueous solution of tetramethylammonium hydroxide, yielding a negative pattern. The resulting resist pattern was evaluated as follows.

[0408] The fabricated patterned mask blank was observed with a top-down SEM (scanning electron microscope) to determine the optimal exposure dose (μC / cm) for resolving a 200 nm 1:1 line and space (LS) at 1:1. 2 The minimum dimension at the exposure dose required to resolve a 200 nm LS at a 1:1 ratio was defined as the LS resolution (limiting resolution), and the minimum dimension at the exposure dose required to resolve a 200 nm square line width as a square was defined as the dot resolution (limiting resolution). The edge roughness (LER) at 200 nm LS was measured using an SEM. The pattern shape was visually determined to be rectangular or not. The evaluation results for each resist composition are shown in Tables 8 to 11.

[0409] [Table 8]

[0410] [Table 9]

[0411] [Table 10]

[0412] [Table 11]

[0413] [4] Etching resistance evaluation [Examples 4-1 to 4-2, Comparative Examples 4-1 to 4-3] Each chemically amplified negative resist composition (R-34, R-49, CR-4, CR-5, CR-6) was spin-coated onto a 152 mm square photomask blank with a chrome outermost surface using ACT-M (Tokyo Electron Limited). The blank was then pre-baked on a hot plate at 110°C for 600 seconds to produce a 120 nm thick resist film. The thickness of the resulting resist film was measured using an optical measuring device, Nanospec (Nanometrics). Measurements were performed at 81 locations on the blank substrate, excluding the outer edge extending 10 mm inward from the outer periphery, and the average film thickness and film thickness range were calculated. The resulting coated substrate was dry-etched using a dry etching apparatus (UNAXIS G4) under the following conditions, and the film loss rate (A / sec) was calculated from the remaining film after etching. The results are shown in Table 12.

[0414] RF1(RIE): Pulse 700V RF2 (ICP): CW 400W Pressure: 6mTorr Cl2: 185sccm O2: 55sccm He: 9.25 sccm Etching time: 75 seconds

[0415] [Table 12]

[0416] All of the chemically amplified negative resist compositions (R-1 to R-76) of the present invention exhibited good resolution, LER, and pattern rectangularity. On the other hand, among the comparative resist compositions (CR-1 to CR-6), CR-2 and CR-3 had low solubility in resist solvents, making it impossible to prepare the resist compositions themselves. CR-1, CR-4, and CR-5 exhibited insufficient optimization of acid diffusion, resulting in degradation of resolution, LER, and pattern rectangularity. Furthermore, dry etching evaluation using R-34 and R-49 also showed better etching resistance than CR-4, CR-5, and CR-6, suggesting that the inclusion of the repeating unit A1 in the polymer is effective in mask processing.

[0417] [5] Evaluation of development residue [Examples 5-1 to 5-29, Comparative Examples 5-1 to 5-3] Each chemically amplified negative resist composition (R-4, R-9, R-14, R-19 to R-33, R-49, R-71, CR-1, CR-4, CR-5, and CR-7) was spin-coated onto a 152 mm square reflective mask blank for EUV exposure masks, whose outermost surface was a chromium compound, using ACT-M (Tokyo Electron Limited). The resulting resist was pre-baked on a hot plate at 110°C for 600 seconds to produce an 80 nm thick resist film. The thickness of the resulting resist film was measured using an optical measuring device, Nanospec (Nanometrics). Measurements were performed at 81 locations on the blank substrate surface, excluding the outer edge extending 10 mm inward from the outer periphery, and the average thickness and thickness range were calculated.

[0418] Each resist film was baked at 120°C for 600 seconds without any patterning, and then developed in a 2.38% by mass aqueous solution of tetramethylammonium hydroxide. The development residue was then evaluated using a mask defect inspection system (M9650 manufactured by Lasertec Corporation). The total number of defects after development is shown in Table 13.

[0419] [Table 13]

[0420] As is clear from the results shown in Table 13, the polymer containing the repeating unit A1 can significantly reduce the number of defects caused by development residues compared to conventional negative resist compositions.

[0421] The method of forming a resist pattern using the chemically amplified negative resist composition of the present invention is useful in the production of semiconductor devices, particularly in photolithography in the processing of transmission and reflection photomask blanks.

Claims

1. A polymer comprising a repeating unit represented by the following formula (A1) and a repeating unit represented by the following formula (A2): 【Chemical 1】 (In the formula, n1 is an integer of 0 to 2. n2 is an integer that satisfies 0≦n2≦5+2(n1)−1. p is an integer of 1 to 5. q is an integer of 1 to 3. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 1 represents a halogen atom, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 10 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 10 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 10 carbon atoms which may be substituted with a halogen atom, or a fluorinated saturated hydrocarbylthio group having 1 to 10 carbon atoms. R 2 is a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. R 3 is a (p+1)-valent hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom. R 4 represents a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 5 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 5 carbon atoms, a fluorinated saturated hydrocarbylcarbonyloxy group having 1 to 5 carbon atoms, a fluorinated saturated hydrocarbyloxycarbonyl group having 1 to 5 carbon atoms, or a fluorinated saturated hydrocarbylthio group having 1 to 5 carbon atoms, and some of the hydrogen atoms of these groups may be substituted with at least one selected from a hydroxy group, a chlorine atom, a bromine atom, an iodine atom, a nitro group, and a cyano group, and at least one selected from an ester bond, an ether bond, a sulfonate ester bond, a carbonate bond, and a carbamate bond may be present between the carbon-carbon bonds of these groups. When q is 1, two R 2 and R 3 Any two of R may be bonded to each other to form a ring together with the sulfur atom to which they are attached. 3 and R 2 Any two of R may be bonded to each other to form a ring together with the sulfur atom to which they are attached. 3 Any two of may be bonded to each other to form a ring together with the sulfur atom to which they are attached. 【Chemistry 2】 (In the formula, a1 is 0 or 1. a2 is an integer of 0 to 2. a3 is an integer that satisfies 0≦a3≦5+2(a2)−a4. a4 is an integer of 1 to 3. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 11 represents a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. A 1 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and the —CH 2 A part of - may be replaced by -O-.)

2. 2. The polymer according to claim 1, wherein the sulfonium salt is represented by the following formula (A1-1): 【Chemistry 3】 (In the formula, n1, n2, p, q, R A , R 1 and R 4 is the same as above. R 5 and R 6 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom other than a fluorine atom, a nitro group, a cyano group, or a heteroatom. r 1 and r 2 are each independently an integer of 0 to 2. 1 is 0≦s 1 ≦(2r 1 +4). 2 is 0≦s 2 ≦(2r 2 +4) is an integer that satisfies the above.

3. R 4 3. The polymer according to claim 2, wherein is a fluorine atom, a trifluoromethyl group, a trifluoromethoxy group, or a trifluoromethylthio group.

4. The polymer according to claim 1, further comprising a repeating unit represented by the following formula (A3): 【Chemistry 4】 (In the formula, b1 is 0 or 1. b2 is an integer of 0 to 2. b3 is an integer that satisfies 0≦b3≦5+2(b2)−b4. b4 is an integer of 1 to 3. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 12 represents a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. R 13 and R 14 are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms which may be substituted with a hydroxy group or a saturated hydrocarbyloxy group, or an aryl group which may have a substituent. 13 and R 14 cannot be a hydrogen atom at the same time. 13 and R 14 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. A 2 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and the —CH 2 A part of - may be substituted with -O-. W 1 is a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, or an aryl group which may have a substituent.

5. The polymer according to claim 4, which contains a repeating unit represented by the following formula (A2-1), and a repeating unit represented by the following formula (A3-1) or a repeating unit represented by the following formula (A3-2): 【Chemistry 5】 (In the formula, a3, a4, b4, R A , R B , Y 2 , R 11 , R 13 , R 14 is the same as above.)

6. The polymer according to claim 1, further comprising at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (A4), a repeating unit represented by the following formula (A5), and a repeating unit represented by the following formula (A6): 【Chemistry 6】 (In the formula, c and d each independently represent an integer of 0 to 4. e1 is 0 or 1. e2 is an integer of 0 to 2. e3 is an integer of 0 to 5.) R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 21 and R 22 are each independently a hydroxy group, a halogen atom, a saturated hydrocarbyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. R 23 is a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms, a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, a saturated hydrocarbylsulfinyl group having 1 to 20 carbon atoms, or a saturated hydrocarbylsulfonyl group having 1 to 20 carbon atoms. A 3 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and the —CH 2 A part of - may be replaced by -O-.)

7. A chemically amplified negative resist composition comprising (A) a base polymer comprising the polymer of claim 1.

8. 8. The chemically amplified negative resist composition according to claim 7, wherein the base polymer further comprises a polymer containing a repeating unit represented by formula (A2) and a repeating unit represented by formula (A3) below, but not containing a repeating unit represented by formula (A1): 【Chemistry 7】 (In the formula, b1 is 0 or 1. b2 is an integer of 0 to 2. b3 is an integer that satisfies 0≦b3≦5+2(b2)−b4. b4 is an integer of 1 to 3. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 12 represents a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. R 13 and R 14 are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms which may be substituted with a hydroxy group or a saturated hydrocarbyloxy group, or an aryl group which may have a substituent. 13 and R 14 cannot be a hydrogen atom at the same time. 13 and R 14 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. A 2 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and the —CH 2 A part of - may be substituted with -O-. W 1 is a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, or an aryl group which may have a substituent.

9. 8. The chemically amplified negative resist composition according to claim 7, wherein the content of repeating units having an aromatic ring skeleton in all repeating units of the polymer contained in said base polymer is 60 mol % or more.

10. 8. The chemically amplified negative resist composition according to claim 7, further comprising (B) a quencher.

11. 8. The chemically amplified negative resist composition according to claim 7, further comprising (C) a photoacid generator.

12. 8. The chemically amplified negative resist composition according to claim 7, wherein the content ratio of the photoacid generator (C) to the quencher (B) is less than 6 in terms of mass ratio.

13. 8. The chemically amplified negative resist composition according to claim 7, further comprising (D) a crosslinking agent.

14. 8. The chemically amplified negative resist composition according to claim 7, which does not contain a crosslinking agent.

15. 8. The chemically amplified negative resist composition according to claim 7, further comprising (E) a fluorine atom-containing polymer that contains at least one selected from the group consisting of a repeating unit represented by the following formula (E1), a repeating unit represented by the following formula (E2), a repeating unit represented by the following formula (E3), and a repeating unit represented by the following formula (E4), and that may further contain at least one selected from the group consisting of a repeating unit represented by the following formula (E5) and a repeating unit represented by the following formula (E6): 【Chemistry 8】 (In the formula, x is an integer of 1 to 3. y is an integer that satisfies 0≦y≦5+2z−x. z is 0 or 1. h is an integer of 1 to 3.) R B are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R C are each independently a hydrogen atom or a methyl group. R 301 , R 302 , R 304 and R 305 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. R 303 , R 306 , R 307 and R 308 are each independently a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or an acid labile group; R 303 , R 306 , R 307 and R 308 When is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be present between the carbon-carbon bond. R 309 is a hydrogen atom or a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a group containing a heteroatom interposed between its carbon-carbon bonds. R 310 is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a heteroatom-containing group interposed between its carbon-carbon bonds. R 311 is a saturated hydrocarbyl group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, and —CH 2 A portion of the - may be substituted with an ester bond or an ether bond. Z 1 is a (g+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (g+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. Z 2 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * is a bond to a carbon atom in the main chain. Z 3 is a single bond, -O-, *-C(=O)-O-Z 31 -Z 32 - or *-C(=O)-NH-Z 31 -Z 32 - is. Z 31 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms. 32 is a single bond, an ester bond, an ether bond, or a sulfonamide bond. * is a bond to a carbon atom in the main chain.)

16. 8. The chemically amplified negative resist composition according to claim 7, further comprising (F) an organic solvent.

17. 17. A method for forming a resist pattern, comprising: forming a resist film on a substrate using the chemically amplified negative resist composition according to any one of claims 7 to 16; irradiating the resist film with a pattern using high-energy rays; and developing the resist film irradiated with the pattern using an alkaline developer.

18. 18. The method for forming a resist pattern according to claim 17, wherein the high-energy radiation is extreme ultraviolet radiation or an electron beam.

19. 18. The method for forming a resist pattern according to claim 17, wherein the outermost surface of the substrate is made of a material containing at least one element selected from the group consisting of chromium, silicon, tantalum, molybdenum, cobalt, nickel, tungsten, and tin.

20. 18. The method for forming a resist pattern according to claim 17, wherein the substrate is a transmission or reflection mask blank.

21. A transmission or reflection mask blank coated with the chemically amplified negative resist composition according to any one of claims 7 to 16.

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