Onium salt monomer, monomeric photo-acid generator, polymer, chemically amplified resist composition, and pattern forming process

Abstract

This invention provides a chemical amplification inhibitor composition for use in photolithography using high-energy rays, exhibiting excellent solvent solubility, high sensitivity, high contrast, and superior photolithography properties such as exposure margin, edge roughness, dimensional uniformity, and depth of focus, and resisting pattern collapse even during the formation of fine patterns. The invention also includes an onium salt monomer, a polymer containing repeating units from the onium salt monomer, a chemical amplification inhibitor composition containing the polymer, and a pattern formation method using the chemical amplification inhibitor composition. One onium salt monomer is composed of a cation represented by formula (a1) and a sulfonic acid anion containing a polymerizable group but without iodine atoms.

Description

[Technical Field]

[0001] This invention relates to onium salt type monomers, polymers, chemical amplification inhibitor compositions and patterning methods. [Previous Technology]

[0002] With the increasing integration and speed of LSI, the miniaturization of patterning is progressing rapidly. In particular, the expansion of the flash memory market and the increase in memory capacity are driving miniaturization. As the most advanced miniaturization technology, mass production of 65nm node devices using ArF lithography is underway, and preparations for mass production of next-generation 45nm node devices using ArF immersion lithography are in progress. As for next-generation 32nm node devices, candidates include liquids with a higher refractive index than water and high refractive index lenses, immersion lithography using ultra-high NA lenses with high refractive index resist films, extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm, and double exposure (double patterning lithography) of ArF lithography, which are currently under research.

[0003] As miniaturization progresses and approaches the diffraction limit of light, the contrast of light gradually decreases. Due to the decrease in light contrast, the resolution and focusing latitude of the hole pattern and trench pattern generated by the positive resist film decrease.

[0004] As patterns become more miniaturized, the edge roughness (LWR) of line patterns and the dimensional uniformity (CDU) of hole patterns are considered problems. Some have pointed to the effects of concentration and aggregation of the base polymer and acid-generating agents, as well as the effects of acid diffusion. Furthermore, with the thinning of resist films, there is a tendency for LWR to increase; accompanying miniaturization, the degradation of LWR due to thinning becomes a serious problem.

[0005] The resist composition for EUV lithography must simultaneously achieve high sensitivity, high resolution, and low light-to-weight ratio (LWR). If the acid diffusion distance is shortened, LWR decreases but sensitivity decreases. For example, reducing the post-exposure baking (PEB) temperature decreases LWR but reduces sensitivity. Increasing the amount of quencher also reduces LWR, but sensitivity decreases. A trade-off between sensitivity and LWR needs to be overcome.

[0006] To suppress acid diffusion, a resisting compound containing repeating units from onium salts of sulfonic acids with polymerizable unsaturated bonds has been proposed (Patent Document 1). Such a polymer-bonded acid generator, because exposure produces polymeric sulfonic acid, exhibits a very short acid diffusion distance. Furthermore, sensitivity can be improved by increasing the ratio of the acid generator. In additive-type acid generators, sensitivity increases with increasing addition amount, but in this case, the acid diffusion distance also increases. Acid diffuses unevenly, so if acid diffusion increases, LWR and CDU deteriorate. Polymer-type acid generators are considered to have a high capacity for balancing sensitivity, LWR, and CDU.

[0007] Iodine atoms have very high absorption in EUV at a wavelength of 13.5 nm, and it has been confirmed that exposure produces secondary electrons from iodine atoms, which is of great importance in EUV lithography. Patent Document 2 describes a photoacid generator in which anions are introduced with iodine atoms, and Patent Document 3 describes a photoacid generator containing polymeric groups in which anions are introduced with iodine atoms. Patent Document 4 describes a photoacid generator in which both cationic and anionic iodine atoms are introduced. While this confirms a certain degree of improvement in lithography performance, there is a concern that iodine atoms may precipitate in solvents due to their low solubility in organic solvents.

[0008] Patent document 5 describes a photoacid generator in which a majority of fluorine atoms are introduced into the cation. Due to the introduction of a majority of fluorine atoms, the solvent solubility of the photoacid generator is improved, but it is not ideal from the perspective of EUV absorption and there is still room for improvement.

[0009] Patent documents 6-11 describe photoacid generators and quenchers (acid diffusion control agents) containing iodine and fluorine atoms in their cations. Patent document 11 also describes onium salt monomers with iodine atoms and polymerizable groups incorporated into their cations. While these developments have confirmed improvements in the performance of photoresist materials, the viewpoint of acid diffusion control remains unsatisfactory.

[0010] The generation of secondary electrons accompanying the EUV absorption of iodine atoms contributes to the high sensitivity of photoresist materials; however, the degradation of lithography performance caused by the diffusion of these secondary electrons is also a problem. Further performance improvement is expected by appropriately controlling the diffusion of these secondary electrons. To meet the requirements of further miniaturization, it is sought to develop photoresist materials that can overcome the aforementioned problems. [Prior Art Documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent No. 4425776 [Patent Document 2] Japanese Patent No. 6720926 [Patent Document 3] Japanese Patent No. 6973274 [Patent Document 4] Japanese Patent No. 7041204 [Patent Document 5] Japanese Patent No. 7389562 [Patent Document 6] Japanese Unexamined Patent Application Publication No. 2021-123579 [Patent Document 7] Japanese Unexamined Patent Application Publication No. 2021-123580 [Patent Document 8] Japanese Unexamined Patent Application Publication No. 2022-123839 [Patent Document 9] Japanese Unexamined Patent Application Publication No. 2023-88869 [Patent Document 10] Japanese Unexamined Patent Application Publication No. 2023-88870 [Patent Document 11] Japanese Unexamined Patent Application Publication No. 2022-28615 [Summary of the Invention]

[0012] (Problem to be solved by the invention) To seek to develop a CDU resist composition that is more sensitive and can improve the LWR and hole patterns of line patterns in a chemical amplification resist composition with acid as a catalyst, and has excellent etching resistance after pattern formation.

[0013] In view of the foregoing, the present invention aims to provide a chemical amplification inhibitor composition that exhibits excellent solvent solubility, high sensitivity, high contrast, and excellent lithography performance such as exposure margin (EL), LWR, CDU, and depth of focus (DOF) in photolithography, particularly using high-energy rays such as KrF excimer laser, ArF excimer laser, electron beam (EB), and EUV, and also demonstrates excellent resistance to pattern collapse and etching resistance even during the formation of fine patterns. The invention also includes a bellium salt monomer, a polymer containing repeating units from the bellium salt monomer, a chemical amplification inhibitor composition containing the polymer, and a patterning method using the chemical amplification inhibitor composition. (Solution to the Problem)

[0014] In order to achieve the aforementioned objective, the inventors of this case have made efforts to explore and have found that polymers containing repeating units of onium salt type monomers composed of sulfonic acid anions containing polymerizable groups and iodine atoms and triaryl strontium cations containing iodine and fluorine atoms have good solvent solubility. By using this polymer as a polymer-bonded photoacid generator, a chemical amplification inhibitor composition with high sensitivity, high contrast, high resolution, improved lithography properties such as LWR and CDU, and excellent etching resistance after pattern formation can be obtained, thus completing the present invention.

[0015] That is, the present invention provides the following onium salt type monomer, polymer, chemical amplification inhibitor composition and pattern formation method. 1. An onium salt type monomer, which is composed of a cation represented by the following formula (a1) and a sulfonic acid anion containing a polymerizable group and not containing an iodine atom, [Chemical 1] wherein, m1 is 0 or 1. m2 is 0 or 1. m3 is 0 or 1. m4 is an integer from 0 to 4. m5 is an integer from 0 to 4. m6 is an integer from 0 to 6. m7 is an integer from 0 to 6. m8 is an integer from 0 to 2. m9 is an integer from 0 to 2. m10 is an integer from 0 to 2. m11 is 0 or 1. m12 is an integer from 0 to 4. m13 is an integer from 0 to 2. m14 is an integer from 0 to 2. However, when m1 is 0, 0 ≤ m6 + m9 ≤ 4, and when m1 is 1, 0 ≤ m6 + m9 ≤ 6. When m2 is 0, 0 ≤ m7 + m10 ≤ 4; when m2 is 1, 0 ≤ m7 + m10 ≤ 6. When m3 is 0, 1 ≤ m4 + m5 + m8 + m14 ≤ 4; when m3 is 1, 1 ≤ m4 + m5 + m8 + m14 ≤ 6. When m11 is 0, 0 ≤ m12 + m13 ≤ 4; when m11 is 1, 0 ≤ m12 + m13 ≤ 6. Also, m4 + m12 ≥ 1. RF1~RF3 are each independently a fluorine atom, a fluorinated saturated hydrocarbon group with 1~6 carbon atoms, a fluorinated saturated hydrocarbon oxygen group with 1~6 carbon atoms, or a fluorinated saturated hydrocarbon sulfide group with 1~6 carbon atoms. When m6 is 2 or more, each RF1 can be the same or different from each other; when m7 is 2 or more, each RF2 can be the same or different from each other; when m5 is 2 or more, each RF3 can be the same or different from each other. R1~R4 can be halogen atoms other than iodine and fluorine atoms, nitro, cyano, or may contain hydrocarbon groups with 1 to 20 carbon atoms, hydrocarbon oxygen groups with 1 to 20 carbon atoms, or hydrocarbon thio groups with 1 to 20 carbon atoms. When m8 is 2, the two R1 atoms can be the same or different, and they can also bond to each other and form a ring with the carbon atoms they are bonded to. When m9 is 2, the two R2 atoms can be the same or different, and they can also bond to each other and form a ring with the carbon atoms they are bonded to. When m10 is 2, the two R3 atoms can be the same or different, and they can also bond to each other and form a ring with the carbon atoms they are bonded to. When m13 is 2, the two R4 atoms can be the same or different, and they can also bond to each other and form a ring with the carbon atoms they are bonded to. Furthermore, the aromatic rings in the strontium cation that are directly bonded to S+ can also bond to each other and form a ring with S+. LA and LB are each independently a single bond, ether bond, ester bond, amide bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond. XL is a single bond, or may contain a heteroatom with 1 to 40 carbon atoms in an alkyl group. 2. As in 1., the onium salt type monomer, wherein the structure of the anion is represented by any of the following formulas (a2-1) to (a2-4), [Chemistry 2] where n1 and n2 are each independently an integer from 0 to 3. n3 is 0 or 1. n4 is an integer from 0 to 4.n5 is an integer from 0 to 4. However, when n3 = 0, 0 ≦ n4 + n5 ≦ 4; when n3 = 1, 0 ≦ n4 + n5 ≦ 6. RA is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. XA is independently a single bond, and may also contain substituents such as phenyl, naphthyl, or *-C(=O)-O-XA1-. XA1 is an aliphatic alkyl group with 1 to 10 carbon atoms, phenyl, or naphthyl; this aliphatic alkyl group may also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. XB is independently a single bond, **-XB1-C(=O)-O-, **-C(=O)-NH-XB1-, or **-O-XB1-. XB1 may also contain heteroatoms and is an alkyl group with 1 to 20 carbon atoms. XC can be a single bond, ***-XC1-C(=O)-O-, ***-C(=O)-NH-XC1-, or ***-O-XC1-. XC1 can be a hydrocarbon group with 1 to 20 carbon atoms, which may also contain heteroatoms. XD can be a single bond, methylene, ethyl, phenyl, fluorinated phenyl, trifluoromethyl-substituted phenyl, *-C(=O)-O-XD1-, *-C(=O)-N(H)-XD1-, or *-O-XD1-. XD1 can be an aliphatic hydrocarbon group with 1 to 6 carbon atoms, phenyl, fluorinated phenyl, or trifluoromethyl-substituted phenyl, and may also contain carbonyl, ester, ether, or hydroxyl groups. * indicates an atomic bond with a carbon atom in the main chain. ** indicates an atomic bond with XA. *** indicates an atomic bond with XB. R5 can be a hydrocarbon group with 1 to 20 carbon atoms, which may also contain heteroatoms. When n5 is 2, 3, or 4, multiple R5s can also bond to each other and form a ring together with the carbon atoms they are bonded to. LC can be a single bond, ether bond, ester bond, carbonyl group, sulfonate bond, carbonate bond, or carbamate bond. Rf1 and Rf2 are each independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Rf3 and Rf4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Rf5 and Rf6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. However, not all Rf5 and Rf6 are simultaneously hydrogen atoms. Rf7 is 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 alkyl thio group having 1 to 6 carbon atoms. 3. An onium salt type monomer as described in 1 or 2, wherein the aforementioned cation is represented by the following formula (a1-1); [Chemical 3] where m4~m10, m12~m14, RF1~RF3, R1~R4, LA, LB and XL are as described above. 4. An onium salt type monomer as described in 3, wherein the aforementioned cation is represented by the following formula (a1-2); [Chemical 4] where m4~m10, RF1~RF3 and R1~R3 ​​are as described above. 5. A monomeric photoacid generator composed of an onium salt type monomer as described in any one of 1 to 4. 6. A polymer containing repeating units from a monomeric photoacid generator as described in 5.7. The polymer of 6. further contains repeating units represented by formula (b1) or (b2) below, [Chemical 5] where RA is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X1 is a single bond, phenyl, naphthyl, *-C(=O)-O-X11- or *-C(=O)-NH-X11-, which may also be substituted by a hydroxyl group, a nitro group, a cyano group, or an alkoxy or halogen atom containing fluorine atoms with 1 to 10 carbon atoms. X11 is a saturated alkyl group with 1 to 10 carbon atoms, phenyl or naphthyl, which may also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. X2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * indicates an atomic bond between the main chain carbon atom and the main chain carbon atom. R11 is a halogen atom, cyano, hydroxyl, nitro, or may contain a hydrocarbon group with 1-20 carbon atoms, a hydrocarbon oxygen group with 1-20 carbon atoms, a hydrocarbon carbonyl group with 2-20 carbon atoms, a hydrocarbon carbonyl oxygen group with 2-20 carbon atoms, or a hydrocarbon oxygen carbonyl group with 2-20 carbon atoms. AL1 and AL2 are each independently an acid-indeterminate group. a is an integer from 0 to 4. 8. Polymers such as 6. or 7. further contain a repeating unit represented by the following formula (b3); [Chemical 6] where b1 is 0 or 1. b2 is an integer from 0 to 3 when b1 is 0, and an integer from 0 to 5 when b1 is 1. RA is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X3 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * indicates an atomic bond between the main chain carbon atom and the main chain carbon atom. R12 and R13 are each independently a hydrogen atom, or may contain a hydrocarbon group with 1 to 20 carbon atoms and a heteroatom. Furthermore, R12 and R13 may also bond to each other and form a ring with the carbon atoms they are bonded to. R14 is a halogen atom, hydroxyl, cyano, nitro, or may contain a hydrocarbon group with 1 to 20 carbon atoms and a hydrocarbon oxygen group with 1 to 20 carbon atoms and a hydrocarbon oxycarbonyl group with 2 to 20 carbon atoms and a hydrocarbon thio group with 1 to 20 carbon atoms or -N(R14A)(R14B). R14A and R14B are each independently a hydrogen atom or a hydrocarbon group with 1 to 6 carbon atoms. When b2 is 2 or more, multiple R14 groups may also bond to each other and form a ring with the carbon atoms of the aromatic rings they are bonded to. X4 is a single bond, an aliphatic hydrocarbon group with 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining them. X5 and X6 are each independently an oxygen atom or a sulfur atom. However, X4 and X6 are bonded to adjacent carbon atoms in the aromatic ring. 9. The polymer of any one of 6 to 8 further contains a repeating unit represented by the following formula (c1), [Chem. 7] where RA is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y1 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * indicates an atomic bond between the polymer and the carbon atom of the main chain.R21 can be a halogen atom, nitro, cyano, carboxyl, or may contain a hydrocarbon group with 1 to 20 carbon atoms, a hydrocarbon oxygen group with 1 to 20 carbon atoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms, a hydrocarbon carbonyl oxygen group with 2 to 20 carbon atoms, or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms. c is an integer from 1 to 4. d is an integer from 0 to 3. However, 1 ≤ c + d ≤ 5. 10. Polymers of any of the following formulas (d1) further contain a repeating unit: [Chemical 8] where RA is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z1 is a single bond, a phenyl group, a naphthyl group, *-C(=O)-O-Z11-, or *-C(=O)-NH-Z11-. This phenyl or naphthyl group may also be substituted with a hydroxyl group, a nitro group, a cyano group, or an alkoxy or halogen atom containing a fluorine atom with 1 to 10 carbon atoms. * indicates an atomic bond between the phenyl group and the carbon atom of the main chain. Z11 is a saturated alkyl group with 1 to 10 carbon atoms, a phenyl group, or a naphthyl group. This saturated alkyl group may also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. R31 is a hydrogen atom, or a group containing at least one of the following structures with 1 to 20 carbon atoms: hydroxyl group (other than phenolic hydroxyl groups), cyano group, carbonyl group, carboxyl group, ether bond, ester bond, sulfonate bond, carbonate bond, lactone ring, sulfonyl lactone ring, and carboxylic anhydride (-C(=O)-OC(=O)-). 11. A chemical amplification inhibitor composition comprising (A) a base polymer containing any one of the polymers described in 6 to 10. 12. The chemical amplification inhibitor composition of 11, further comprising (B) an organic solvent. 13. The chemical amplification inhibitor composition of 11 or 12, further comprising (C) a quencher. 14. The chemical amplification inhibitor composition of any one of 11 to 13, further comprising (D) an acid generator. 15. The chemical amplification inhibitor composition of any one of 11 to 14, further comprising (E) a surfactant. 16. The chemical amplification inhibitor composition of any one of 11 to 15, further comprising (F) a dissolution inhibitor. 17. A pattern forming method, comprising the following steps: forming a resist film on a substrate using a chemical amplifying resist composition as described in any one of 11. to 16; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developer. 18. The pattern forming method of 17, wherein the high-energy radiation is an ArF excimer laser with a wavelength of 193 nm, a KrF excimer laser with a wavelength of 248 nm, an electron beam, or extreme ultraviolet radiation with a wavelength of 3 to 15 nm. (Effects of the invention).

[0016] This polymer contains repeating units of onium salt monomers composed of sulfonic acid anions containing polymerizable groups and lacking iodine atoms, and triarylstrom cations containing iodine and fluorine atoms, which generate acid upon exposure. Due to the increased lipophilicity caused by the fluorine atoms, it exhibits good solvent solubility. The triarylstrom cations containing iodine and fluorine atoms show particularly strong EUV absorption due to iodine atoms in 13.5 nm EUV lithography, resulting in the generation of secondary electrons from iodine atoms during exposure. Furthermore, the electron attraction effect of fluorine atoms lowers the energy level of the lowest empty molecular orbital (LUMO) in the leading-edge orbital theory, making it more receptive to the generated secondary electrons, thus promoting cation decomposition and effectively generating acid. Moreover, the presence of iodine atoms near the strom cation shortens the diffusion distance of secondary electrons, allowing them to contribute efficiently to cation decomposition. On the other hand, sulfonic acid anions containing polymerizable groups but lacking iodine atoms reduce the generation of secondary electrons due to the absence of iodine atoms, thus suppressing the degradation of lithography performance associated with the diffusion of secondary electrons. Furthermore, since the generated acid bonds are embedded in the polymer backbone structure, they exhibit low acid diffusion. This prevents resolution degradation caused by acid diffusion blurring, improving LWR and CDU, and also resulting in excellent etching resistance after pattern formation.

Implementation Method

[0017] [Onium Salt Type Monomer] The onium salt type monomer of the present invention contains a cation represented by the following formula (a1). [Chemical 9]

[0018] In formula (a1), m1 is 0 or 1. When m1 is 0, it is a benzene ring; when m1 is 1, it is a naphthalene ring. Considering solvent solubility, a benzene ring with m2 being 0 is preferred. m2 is 0 or 1. When m2 is 0, it is a benzene ring; when m2 is 1, it is a naphthalene ring. Considering solvent solubility, a benzene ring with m3 being 0 is preferred. m3 is 0 or 1. When m3 is 0, it is a benzene ring; when m3 is 1, it is a naphthalene ring. Considering solvent solubility, a benzene ring with m3 being 0 is preferred.

[0019] In formula (a1), m4 is an integer from 0 to 4. The more iodine atoms in the cation structure, the higher the absorption, especially for EUV, but the less solvent solubility there will be concerns about precipitation in the inhibitor composition. Therefore, m4 is preferred to be 0, 1, 2 or 3, with 0, 1 or 2 being even better.

[0020] In formula (a1), m5 is an integer from 0 to 4. Considering raw material scheduling, m5 is preferably 0, 1, 2, or 3, with 0, 1, or 2 being even better. m6 is an integer from 0 to 6. Considering raw material scheduling, m6 is preferably 0, 1, 2, or 3, with 0, 1, or 2 being even better. m7 is an integer from 0 to 6. Considering raw material scheduling, m7 is preferably 0, 1, 2, or 3, with 0, 1, or 2 being even better.

[0021] In formula (a1), m8 is an integer from 0 to 2. Considering the raw material scheduling perspective, it is preferable for m8 to be 0 or 1. m9 is an integer from 0 to 2. Considering the raw material scheduling perspective, it is preferable for m9 to be 0 or 1. m10 is an integer from 0 to 2. Considering the raw material scheduling perspective, it is preferable for m10 to be 0 or 1.

[0022] In formula (a1), m11 is 0 or 1. When m11 is 0, it is a benzene ring; when m11 is 1, it is a naphthalene ring. Considering the solvent solubility, a benzene ring with m11 of 0 is preferred.

[0023] In formula (a1), m12 is an integer from 0 to 4. The more iodine atoms in the cation structure, the higher the absorption, especially for EUV, but the less solvent solubility there will be concerns about precipitation in the inhibitor composition. Therefore, m12 is preferred to be 0, 1, 2 or 3, with 0, 1 or 2 being even better.

[0024] In formula (a1), m13 is an integer from 0 to 2. From the perspective of raw material scheduling, it is better for m13 to be 0 or 1. m14 is an integer from 0 to 2. From the perspective of synthesis, it is better for m14 to be 0 or 1.

[0025] When m1 is 0, 0 ≦ m6 + m9 ≦ 4; when m1 is 1, 0 ≦ m6 + m9 ≦ 6. When m2 is 0, 0 ≦ m7 + m10 ≦ 4; when m2 is 1, 0 ≦ m7 + m10 ≦ 6. When m3 is 0, 1 ≦ m4 + m5 + m8 + m14 ≦ 4; when m3 is 1, 1 ≦ m4 + m5 + m8 + m14 ≦ 6. When m11 is 0, 0 ≦ m12 + m13 ≦ 4; when m11 is 1, 0 ≦ m12 + m13 ≦ 6. Also, m4 + m12 ≧ 1.

[0026] In formula (a1), RF1 to RF3 are each independently a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxygen group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group having 1 to 6 carbon atoms. Among these, trifluoromethyl, trifluoromethoxy, and trifluorothiomethoxy are preferred. When m6 is 2 or more, each RF1 may be the same or different from each other; when m7 is 2 or more, each RF2 may be the same or different from each other; when m5 is 2 or more, each RF3 may be the same or different from each other.

[0027] In formula (a1), R1~R4 are halogen atoms other than iodine and fluorine atoms, nitro, cyano, or may contain a hydrocarbon group with 1~20 carbon atoms containing heteroatoms, or a hydrocarbon oxy group with 1~20 carbon atoms containing heteroatoms, or a hydrocarbon thio group with 1~20 carbon atoms containing heteroatoms. The hydrocarbon base of the aforementioned hydrocarbon group, hydrocarbon oxy group, and hydrocarbon thio group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkyl groups with 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecanyl, octadecyl, nonadecanyl, and eicosyl; cyclic saturated hydrocarbon groups with 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norcamphenyl, and adamantyl; alkenyl groups with 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups with 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups with 6 to 20 carbon atoms, such as phenyl and naphthyl; aralkyl groups with 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups composed of these groups. Furthermore, some or all of the hydrogen atoms in the hydrocarbon group, hydrocarbon oxygen group, and hydrocarbon sulfide group mentioned above can be replaced by a group containing heteroatoms such as oxygen atom, sulfur atom, nitrogen atom, and halogen atom. The -CH2- part of the aforementioned hydrocarbon group can also be replaced by a group containing heteroatoms such as oxygen atom, sulfur atom, and nitrogen atom. As a result, it may also contain hydroxyl group, cyano group, fluorine atom, chlorine atom, bromine atom, iodine atom, carbonyl group, ether bond, ester bond, sulfonate bond, carbonate bond, lactone ring, sulfonolactone ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl group, etc.

[0028] Furthermore, when m8 is 2, the two R1 atoms can be the same or different, and the two R1 atoms can also bond to each other and form a ring together with the carbon atoms they are bonded to. When m9 is 2, the two R2 atoms can be the same or different, and the two R2 atoms can also bond to each other and form a ring together with the carbon atoms they are bonded to. When m10 is 2, the two R3 atoms can be the same or different, and the two R3 atoms can also bond to each other and form a ring together with the carbon atoms they are bonded to. When m13 is 2, the two R4 atoms can be the same or different, and the two R4 atoms can also bond to each other and form a ring together with the carbon atoms they are bonded to. Specific examples of the rings formed in this case include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norcamphene rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the aforementioned ring can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. Similarly, some of the -CH2- groups in the aforementioned ring can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, the ring may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulfonolactone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0029] Furthermore, the aromatic rings in the strontium cation represented by formula (a1) that are directly bonded to S+ can also bond to each other and form a ring together with S+. Specific examples of the aforementioned ring structures can be listed in the following formulas, etc. [Chemical 10] In the formula, the chain lines represent atomic bonds.

[0030] In formula (a1), LA and LB are each independently a single bond, ether bond, ester bond, amide bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond. Among these, it is preferred that LA is a single bond, ether bond, ester bond, or sulfonate bond, with ester bond or sulfonate bond being more preferred. It is preferred that LB is a single bond, ether bond, or ester bond, with single bond being more preferred.

[0031] In formula (a1), XL is a single bond, or may contain a heteroatom and be a carbon group with 1 to 40 carbon atoms. Specific examples of the aforementioned carbon group containing heteroatoms and having 1 to 40 carbon atoms include straight-chain, branched, and cyclic forms, such as alkyldiyl, cyclic saturated carbon groups, and aryl groups. Specific examples of the aforementioned heteroatoms include oxygen atoms, nitrogen atoms, and sulfur atoms.

[0032] XL can also contain alkyl groups with 1 to 40 carbon atoms, and specific examples are listed below, but are not limited to these. Also, in the following formula, * represents the atomic bonds with LA and LB. [Chemistry 11]

[0033] [Chemical 12]

[0034] [Chemical 13]

[0035] [Chemical 14]

[0036] Among these, XL-0~XL-22, XL-29~XL-34 and XL-47~XL-58 are preferred.

[0037] The strontium cation represented by formula (a1) is preferably represented by the following formula (a1-1). [Chemical 15] In the formula, m4~m10, m12~m14, RF1~RF3, R1~R4, LA, LB and XL are as described above.

[0038] The cation represented by formula (a1-1) is preferably represented by formula (a1-2). [Chemical 16] In the formula, m4~m10, RF1~RF3 and R1~R3 ​​are as described above.

[0039] Specific examples of strontium cations represented by formula (a1) are listed below, but are not limited to these. Also, in the following formula, Me is a methyl group. [Chemistry 17]

[0040] [Chemical 18]

[0041] [Chemical 19]

[0042] [Chemical 20]

[0043] [Chemical 21]

[0044] [Chemical 22]

[0045] [Chemical 23]

[0046] [Chemical 24]

[0047] [Chemical 25]

[0048] [Chemical 26]

[0049] [Chemical 27]

[0050] [Chemical 28]

[0051] [Chemical 29]

[0052] [Chemical 30]

[0053] [Chemical 31]

[0054] [Chemical 32]

[0055] [Chemical 33]

[0056] [Chemical 34]

[0057] [Chemical 35]

[0058] [Chemical 36]

[0059] [Chemical 37]

[0060] [Chemical 38]

[0061] [Chemical 39]

[0062] [Chemical 40]

[0063] [Chemical 41]

[0064] [Chemical 42]

[0065] [Chemical 43]

[0066] [Chemical 44]

[0067] The onium salt type monomer of the present invention contains a sulfonic acid anion containing a polymerizable group and without iodine atoms.

[0068] It is preferable that the aforementioned sulfonic acid anion is represented by any one of the following formulas (a2-1) to (a2-4). [Chemical 45]

[0069] In equations (a2-1) to (a2-4), n1 and n2 are each independently integers from 0 to 3, with 1 being preferable. n3 is 0 or 1. n4 is an integer from 0 to 4. n5 is an integer from 0 to 4. However, when n3 = 0, 0 ≦ n4 + n5 ≦ 4, and when n3 = 1, 0 ≦ n4 + n5 ≦ 6.

[0070] In formulas (a2-1) to (a2-4), RA is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. XA is independently a single bond, and may also have substituents such as phenyl, naphthyl, or *-C(=O)-O-XA1-. XA1 is an aliphatic alkyl group, phenyl, or naphthyl group with 1 to 10 carbon atoms, which may also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. XB is independently a single bond, **-XB1-C(=O)-O-, **-C(=O)-NH-XB1-, or **-O-XB1-. XB1 may also contain heteroatoms and is an alkyl group with 1 to 20 carbon atoms. XC is independently a single bond, ***-XC1-C(=O)-O-, ***-C(=O)-NH-XC1-, or ***-O-XC1-. XC1 is an alkyl group with 1 to 20 carbon atoms, which may also contain heteroatoms. XD is a single bond, methylene, ethyl, phenyl, fluorinated phenyl, trifluoromethyl-substituted phenyl, *-C(=O)-O-XD1-, *-C(=O)-N(H)-XD1-, or *-O-XD1-. XD1 is an aliphatic alkyl group with 1 to 6 carbon atoms, phenyl, fluorinated phenyl, or trifluoromethyl-substituted phenyl, which may also contain carbonyl, ester, ether, or hydroxyl groups. * indicates an atomic bond with a carbon atom in the main chain. ** represents an atomic bond with XA. *** represents an atomic bond with XB.

[0071] The aliphatic alkyl groups represented by XA1 and XD1 can be straight-chain, branched, or cyclic. Specific examples include alkyl diyl groups such as methane-1,1-diyl, ethane-1,2-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-1,3-diyl, propane-2,2-diyl, butane-1,1-diyl, butane-1,2-diyl, butane-1,3-diyl, butane-2,3-diyl, butane-1,4-diyl, 1,1-dimethylethane-1,2-diyl, pentane-1,5-diyl, 2-methylbutane-1,2-diyl, and hexane-1,6-diyl; cyclopropane diyl, cyclobutane diyl, cyclopentane diyl, cyclohexane diyl, etc.; and groups obtained by combining them.

[0072] The extended hydrocarbon groups represented by XB1 and XC1 can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. Specific examples are listed below, but are not limited to these. [Chem. 46] In the formula, the chain lines are atomic bonds.

[0073] In formulas (a2-1) to (a2-3), LC represents a single bond, ether bond, ester bond, carbonyl group, sulfonate bond, carbonate bond, or carbamate bond. Among these, from a synthetic point of view, ether bonds, ester bonds, and carbonyl groups are more ideal, with ester bonds and carbonyl groups being even more ideal.

[0074] In formula (a2-1), Rf1 and Rf2 are each independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Among these, for Rf1 and Rf2, it is preferable that both are fluorine atoms to improve the acid strength of the produced acid. Rf3 and Rf4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Among these, it is preferable that at least one of Rf3 and Rf4 is trifluoromethyl to improve solvent solubility.

[0075] In formula (a2-2), Rf5 and Rf6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. However, Rf5 and Rf6 do not necessarily both be hydrogen atoms. Among these, for the purpose of improving solvent solubility, it is preferable that at least one of Rf5 and Rf6 is trifluoromethyl.

[0076] In formula (a2-3), Rf7 is 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 alkyl thio group having 1 to 6 carbon atoms. Ideally, Rf7 should be a fluorine atom, trifluoromethyl, difluoromethyl, trifluoromethoxy, difluoromethoxy, trifluoromethylthio, or difluoromethylthio, with fluorine atom, trifluoromethyl, or trifluoromethoxy being more ideal. When n4 is 2, 3, or 4, each Rf7 can be the same or different from the others.

[0077] In formula (a2-3), R5 is a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkyl groups with 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, decadecyl, heptadecyl, octadecyl, nonadecanyl, and icosyl; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornel, and adamantyl; alkenyl groups with 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclohexenyl and other cyclounsaturated hydrocarbon groups with 3 to 20 carbon atoms; aryl groups with 6 to 20 carbon atoms, such as phenyl and naphthyl; aralkyl groups with 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining them. Among these, aryl is preferred. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms. Similarly, the -CH2- portion of the aforementioned hydrocarbon group can also be replaced by a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. This can result in the presence of hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone, sulfonate, carboxylic anhydride (-C(=O)-OC(=O)-), or haloalkyl groups. Also, when n5 is 2, 3, or 4, each R5 can be the same or different from the others.

[0078] Furthermore, when n5 is 2, 3, or 4, multiple R5s can also bond to each other and form a ring together with the carbon atoms of the aromatic rings they are bonded to. Specific examples of the rings formed in this case include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the aforementioned rings can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the -CH2- in the aforementioned rings can also be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc. As a result, the rings may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulopentalide rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0079] Specific examples of anions represented by formula (a2-1) are listed below, but are not limited to these. Also, in the following formula, RA is as described above. [Chemistry 47]

[0080] [Chemistry 48]

[0081] [Chemistry 49]

[0082] [Chemical 50]

[0083] [Chemical 51]

[0084] [Chemical 52]

[0085] Specific examples of anions represented by formula (a2-2) can be listed below, but are not limited to these. Also, in the following formula, RA is as described above. [Chemistry 53]

[0086] [Chemical 54]

[0087] [Chemical 55]

[0088] [Chemical 56]

[0089] [Chemical 57]

[0090] [Chemical 58]

[0091] Specific examples of anions represented by formula (a2-3) are listed below, but are not limited to these. Also, in the following formula, RA is as described above. [Chem. 59]

[0092] [Chemical 60]

[0093] [Chemical 61]

[0094] [Chemical 62]

[0095] [Chemical 63]

[0096] [Chemical 64]

[0097] [Chemical 65]

[0098] [Chemical 66]

[0099] [Chemical 67]

[0100] [Transformation 68]

[0101] [Chemistry 69]

[0102] [Chemical 70]

[0103] [Chemistry 71]

[0104] Specific examples of anions represented by formula (a2-4) are listed below, but are not limited to these. Also, in the following formula, RA is as described above. [Chemistry 72]

[0105] Specific examples of the onium salt type monomer of the present invention are any combination of the aforementioned anions and cations.

[0106] The onium salt type monomer of the present invention can be synthesized, for example, by the same method as that of the strontium salt having polymerizable anions disclosed in Japanese Patent No. 5201363, but is not limited thereto.

[0107] [Polymer] The polymer of the present invention contains repeating units (hereinafter also referred to as repeating unit A) of onium salt type monomers composed of a cation represented by formula (a1) and a sulfonic acid anion containing a polymerizable group and not containing an iodine atom.

[0108] The polymer of this invention serves as a base polymer in the composition of a chemical amplification inhibitor and also as a polymer-bonded photoacid generator. The triarylstrom cation containing iodine and fluorine atoms exhibits particularly high EUV absorption due to iodine atoms in EUV lithography at a wavelength of 13.5 nm, resulting in the generation of secondary electrons from iodine atoms during exposure. Furthermore, the electron attraction effect caused by fluorine atoms lowers the energy level of the lowest empty molecular orbital (LUMO) in the leading-edge orbital theory, making it more susceptible to the generation of secondary electrons. Therefore, the decomposition of cations in the same nearby structure is promoted, effectively generating acid. On the other hand, the sulfonic acid anion substituted with a polymeric group does not necessarily contain iodine atoms. When the anion contains iodine atoms, the secondary electrons generated from the iodine atoms travel a long physical distance to the strom cation, leading to secondary electron diffusion and thus deteriorating lithography performance. Furthermore, iodine atoms are relatively poorly water-soluble, so the iodine atoms in the anion will reduce the solubility of the polymer after the acid desorption reaction. This is especially true for positive resists in alkaline development, where the reduced solubility of the polymer in the alkaline developer after the acid desorption reaction increases the likelihood of development defects. Therefore, the polymer of this invention, by appropriately controlling the diffusion of secondary electrons, improves various lithography properties and reduces the risk of development defects, making it particularly suitable as a material for chemically amplified positive resist components.

[0109] The aforementioned polymer may further contain repeating units represented by formula (b1) (hereinafter also referred to as repeating unit b1.) or repeating units represented by formula (b2) (hereinafter also referred to as repeating unit b2.). [Chemistry 73]

[0110] In formulas (b1) and (b2), RA is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0111] In formula (b1), X1 is a single bond, an phenyl group, a naphthyl group, *-C(=O)-O-X11- or *-C(=O)-NH-X11-. The phenyl or naphthyl group may also be substituted with a hydroxyl group, a nitro group, a cyano group, or an alkoxy group containing fluorine atoms with 1 to 10 carbon atoms, or a halogen atom. X11 is a saturated alkyl group with 1 to 10 carbon atoms, an phenyl group, or a naphthyl group. The saturated alkyl group may also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. * indicates an atomic bond between the main chain carbon atom and the main chain carbon atom.

[0112] In formula (b2), X2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * indicates an atomic bond between the X2 and the carbon atom of the main chain. R11 is a halogen atom, cyano, hydroxyl, nitro, or may contain a hydrocarbon group with 1 to 20 carbon atoms of heteroatoms, a hydrocarbon oxygen group with 1 to 20 carbon atoms of heteroatoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms of heteroatoms, a hydrocarbon carbonyl oxygen group with 2 to 20 carbon atoms of heteroatoms, or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms of heteroatoms. a is an integer from 0 to 4, preferably 0 or 1.

[0113] In formulas (b1) and (b2), AL1 and AL2 are each independently acid unstable groups. Specific examples of the aforementioned acid unstable groups include those described in Japanese Patent Application Publication No. 2013-80033 and Japanese Patent Application Publication No. 2013-83821, but are not limited to these.

[0114] Generally speaking, specific examples of the aforementioned unstable acid groups are represented by the following formulas (AL-1) to (AL-3). [Chemistry 74] In the formulas, * represents an atomic bond.

[0115] In formulas (AL-1) and (AL-2), RL1 and RL2 are each independently a hydrocarbon group with 1 to 40 carbon atoms, and may also contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, and iodine atoms. The aforementioned hydrocarbon group may be linear, branched, or cyclic. It is preferred that the aforementioned hydrocarbon group has 1 to 20 carbon atoms.

[0116] In formula (AL-1), b is an integer from 0 to 10, and an integer from 1 to 5 is preferred.

[0117] In formula (AL-2), RL3 and RL4 are each independently a hydrogen atom or a hydrocarbon group with 1 to 20 carbon atoms, and may also contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, and iodine atoms. The aforementioned hydrocarbon groups can be linear, branched, or cyclic. Furthermore, any two of RL2, RL3, and RL4 can also bond to each other and form a ring with 3 to 20 carbon atoms together with the carbon atoms they are bonded to, or carbon atoms and oxygen atoms. The aforementioned rings with 4 to 16 carbon atoms are preferred, especially alicyclic rings.

[0118] In formula (AL-3), RL5, RL6, and RL7 are each independently a hydrocarbon group with 1 to 20 carbon atoms, and may also contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, and iodine atoms. The aforementioned hydrocarbon groups can be linear, branched, or cyclic. Furthermore, any two of RL5, RL6, and RL7 can bond to each other and form a ring with 3 to 20 carbon atoms together with the carbon atoms they are bonded to. The aforementioned rings with 4 to 16 carbon atoms are preferred, especially alicyclic rings.

[0119] Specific examples of repeating unit b1 can be listed below, but are not limited to these. Also, in the following formula, RA and AL1 are as described above. [Chemistry 75]

[0120] [Chemistry 76]

[0121] [Chemistry 77]

[0122] [Transformation 78]

[0123] [Chemistry 79]

[0124] [Chemical 80]

[0125] [Chemistry 81]

[0126] Specific examples of repeating unit b2 can be listed below, but are not limited to these. Also, in the following formula, RA and AL2 are as described above. [Chemistry 82]

[0127] [Chemistry 83]

[0128] [Chemical 84]

[0129] The aforementioned polymer may also contain repeating units represented by the following formula (b3) (hereinafter also referred to as repeating unit b3). [Chemistry 85]

[0130] In formula (b3), b1 is 0 or 1. When b1 is 0, it is a benzene ring; when b1 is 1, it is a naphthalene ring. However, considering solvent solubility, a benzene ring with b1 of 0 is preferred. b2 is an integer from 0 to 3 when b1 is 0, and an integer from 0 to 5 when b1 is 1. Considering raw material preparation, b2 of 0, 1, 2, or 3 is preferred, with 0, 1, or 2 being even better.

[0131] In formula (b3), RA is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, hydrogen atom and methyl group are preferred, with hydrogen atom being more ideal.

[0132] In formula (b3), X3 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * indicates an atomic bond between the X3 and a carbon atom in the main chain. Among these, a single bond and *-C(=O)-O- are preferred, with a single bond being more ideal.

[0133] In formula (b3), R12 and R13 are each independently hydrogen atoms, or may contain hydrocarbon groups with 1 to 20 carbon atoms containing heteroatoms. The aforementioned hydrocarbon groups may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkyl groups with 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, decadecyl, heptadecyl, octadecyl, nonadecanyl, and icosyl; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norcamphenyl, and adamantyl; alkenyl groups with 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclohexenyl and other cyclounsaturated hydrocarbon groups with 3 to 20 carbon atoms; aryl groups with 6 to 20 carbon atoms, such as phenyl and naphthyl; aralkyl groups with 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining them. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. The -CH2- portion of the aforementioned hydrocarbon group can also be replaced by a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulcinolone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0134] Furthermore, R12 and R13 can also bond to each other and form a ring together with the carbon atoms they are bonded to. Specific examples of the rings formed in this case include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the aforementioned rings can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the -CH2- in the aforementioned rings can also be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc. As a result, the rings may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulopentalide rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0135] In formula (b3), R14 can be a halogen atom, hydroxyl group, cyano group, nitro group, or a hydrocarbon group containing 1 to 20 carbon atoms with heteroatoms, a hydrocarbon oxygen group containing 1 to 20 carbon atoms with heteroatoms, a hydrocarbon oxycarbonyl group containing 2 to 20 carbon atoms with heteroatoms, or a hydrocarbon thio group containing 1 to 20 carbon atoms, or -N(R14A)(R14B). R14A and R14B are each independently a hydrogen atom or a hydrocarbon group containing 1 to 6 carbon atoms. It is preferred that the aforementioned halogen atom is a fluorine atom, chlorine atom, bromine atom, or iodine atom, with fluorine atom or iodine atom being more preferred. The hydrocarbon base of the aforementioned hydrocarbon group, hydrocarbon oxygen group, hydrocarbon oxycarbonyl group, and hydrocarbon thio group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples are the same as those exemplified for hydrocarbon groups represented by R12 and R13. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms. Similarly, the -CH2- portion of the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. This can result in the presence of hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone, sulfonate, carboxylic anhydride (-C(=O)-OC(=O)-), or haloalkyl groups. When b2 is 2 or more, each R14 can be the same or different from the others.

[0136] Furthermore, when b2 is 2 or more, multiple R14 atoms can also bond to each other and form a ring together with the carbon atoms of the aromatic rings they are bonded to. Specific examples of the rings formed in this case include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the aforementioned rings can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the -CH2- in the aforementioned rings can also be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc. As a result, hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulopentalide rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0137] In formula (b3), X4 is a single bond, an aliphatic hydrocarbon group with 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a combination thereof. Among these, considering the source material distribution, a single bond, a carbonyl group, or a sulfonyl group is preferred; considering the polar group generated after the reaction, a single bond or a carbonyl group is more preferred.

[0138] In formula (b3), X5 and X6 are each independently an oxygen atom or a sulfur atom. However, X4 and X6 are bonded to adjacent carbon atoms on the aromatic ring. X5 and X6 can be the same or different from each other. From the perspective of reactivity, it is better for X5 and X6 to be oxygen atoms.

[0139] Specific examples of repeating unit b3 can be listed below, but are not limited to these. Also, in the following formula, RA is as described above, and Me is methyl. Furthermore, the bonding positions of various substituents on the aromatic ring can also be interchanged. [Chem. 86]

[0140] [Chemical 87]

[0141] [Chemical 88]

[0142] [Chemistry 89]

[0143] [Chemical 90]

[0144] [Chemical 91]

[0145] [Chemical 92]

[0146] [Chemical 93]

[0147] [Chemical 94]

[0148] [Chemical 95]

[0149] [Chemical 96]

[0150] [Chemical 97]

[0151] [Chemical 98]

[0152] [Chemical 99]

[0153] [Chemical 100]

[0154] [Chemical 101]

[0155] [Chemical 102]

[0156] [Chemical 103]

[0157] [Chemical 104]

[0158] [Chemical 105]

[0159] [Chemical 106]

[0160] [Chemistry 107]

[0161] [Chemical 108]

[0162] [Chemistry 109]

[0163] [Chemical 110]

[0164] [Chemical 111]

[0165] [Chemical 112]

[0166] [Chemical 113]

[0167] [Chemical 114]

[0168] [Chemical 115]

[0169] [Chemical 116]

[0170] [Chemistry 117]

[0171] [Chemical 118]

[0172] [Chemistry 119]

[0173] [Chemical 120]

[0174] [Chemistry 121]

[0175] [Chemistry 122]

[0176] [Chemistry 123]

[0177] [Chemistry 124]

[0178] [Chemical 125]

[0179] [Chemistry 126]

[0180] [Chemistry 127]

[0181] [Chemistry 128]

[0182] [Chemistry 129]

[0183] [Chemistry 130]

[0184] [Chemistry 131]

[0185] [Chemistry 132]

[0186] [Chemistry 133]

[0187] [Chemistry 134]

[0188] [Chemistry 135]

[0189] Preferably, the aforementioned polymer further contains a repeating unit represented by the following formula (c1) (hereinafter also referred to as repeating unit c). [Chemical 136]

[0190] In formula (c1), RA is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y1 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * indicates an atomic bond between the bond and the carbon atom of the main chain. R21 is a halogen atom, a nitro group, a cyano group, a carboxyl group, or may contain a hydrocarbon group with 1 to 20 carbon atoms (heteroatomic), a hydrocarbon oxygen group with 1 to 20 carbon atoms (heteroatomic), a hydrocarbon carbonyl group with 2 to 20 carbon atoms (heteroatomic), a hydrocarbon carbonyl oxygen group with 2 to 20 carbon atoms (heteroatomic), or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms (heteroatomic). c is an integer from 1 to 4. d is an integer from 0 to 3. Only 1 ≤ c + d ≤ 5.

[0191] Specific examples of repeating unit c can be listed below, but are not limited to these. Also, in the following formula, RA is as described above. [Chemistry 137]

[0192] [Chemistry 138]

[0193] [Chemistry 139]

[0194] [Chemical 140]

[0195] [Chemistry 141]

[0196] Preferably, the aforementioned polymer further contains a repeating unit represented by the following formula (d1) (hereinafter also referred to as repeating unit d). [Chemical 142]

[0197] In formula (d1), RA is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z1 is a single bond, an phenyl group, an anthraquinone group, *-C(=O)-O-Z11-, or *-C(=O)-NH-Z11-. The phenyl group or anthraquinone group may also be replaced by a hydroxyl group, a nitro group, a cyano group, or an alkoxy group containing fluorine atoms with 1 to 10 carbon atoms, or a halogen atom. * indicates an atomic bond between the phenyl group and the carbon atom of the main chain. Z11 is a saturated alkyl group with 1 to 10 carbon atoms, an phenyl group, or an anthraquinone group. The saturated alkyl group may also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. R31 is a group with 1 to 20 carbon atoms, consisting of at least one of the following: a hydroxyl group (other than phenolic hydroxyl groups), a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sulcinolone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-).

[0198] Specific examples of repeating unit d can be listed below, but are not limited to these. Also, in the following formula, RA is as described above. [Chemistry 143]

[0199] [Chemistry 144]

[0200] [Chemistry 145]

[0201] [Chemistry 146]

[0202] [Chemistry 147]

[0203] [Chemical 148]

[0204] [Chemistry 149]

[0205] [Chemical 150]

[0206] [Chemistry 151]

[0207] [Chemistry 152]

[0208] [Chemistry 153]

[0209] [Chemical 154]

[0210] [Chemistry 155]

[0211] [Chemistry 156]

[0212] [Chemistry 157]

[0213] [Chemistry 158]

[0214] Regarding the repeating unit d, ArF lithography is preferred, especially those with lactone rings as polar groups, while KrF lithography, EB lithography and EUV lithography are preferred, especially those with phenol sites.

[0215] The aforementioned polymer may further contain repeating units (hereinafter also referred to as repeating units e) having a structure in which hydroxyl groups are protected by acid-destabilized groups. Repeating unit e is not particularly limited as long as it has one or more protected hydroxyl groups and the protecting groups decompose and generate hydroxyl groups due to acid action; however, the following formula (e1) is preferred. [Chem. 159]

[0216] In formula (e1), RA is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R41 is a (e+1) valence hydrocarbon with 1 to 30 carbon atoms, which may also contain heteroatoms. R42 is an acid-destabilized group. e is an integer from 1 to 4.

[0217] In formula (e1), the acid-unstable group represented by R42 can be any group that has been deprotected by acid and produces a hydroxyl group. The structure of R42 is not particularly limited, but acetal, ketal, alkoxycarbonyl, or alkoxymethyl as represented by formula (e2) are preferred, especially alkoxymethyl as represented by formula (e2). [Chemical 160] In the formula, * represents an atomic bond. R43 is a hydrocarbon group with 1 to 15 carbon atoms.

[0218] The specific examples of the acid-indeterminate group represented by R42, the alkoxymethyl group represented by formula (e2), and the repeating unit e are the same as the examples of the repeating unit d described in Japanese Patent Application Publication No. 2020-111564.

[0219] The aforementioned polymer may further contain repeating units f derived from indene, benzofuran, benzothiophene, vinylnaphthalene, cromoglycan, coumarin, norcamphediene, or derivatives thereof. Specific examples of monomers giving repeating units f are listed below, but are not limited to these. [Chem. 161]

[0220] The aforementioned polymer may also contain repeating units g derived from styrene, dihydroindene, vinylpyridine or vinylcarbazole.

[0221] In the polymer of the present invention, the content ratio of repeating units a, b1, b2, b3, c, d, e, f and g is preferably 0 < a ≤ 0.5, 0 ≤ b1 ≤ 0.8, 0 ≤ b2 ≤ 0.8, 0 ≤ b3 ≤ 0.6, 0 ≤ c ≤ 0.8, 0 ≤ d ≤ 0.5, 0 ≦e≦0.3, 0≦f≦0.3 and 0≦g≦0.3, preferably 0<a≦0.4, 0≦b1≦0.7, 0≦b2≦0.7, 0≦b3≦0.5, 0≦c≦0.7, 0≦d≦0.4, 0≦e≦0.2, 0≦f≦0.2 and 0≦g≦0.2. Only a+b1+b2+b3+c+d+e+f+g≦1.0.

[0222] Ideally, the weight-average molecular weight (Mw) of the aforementioned polymer should be between 1,000 and 500,000, and more ideally between 3,000 and 100,000. If Mw is within this range, sufficient etching resistance can be obtained, and there is no risk of resolution degradation due to the difference in dissolution rate before and after exposure. Furthermore, in this invention, Mw is a converted value of polystyrene obtained by gel permeation chromatography (GPC) using tetrahydrofuran (THF) or N,N-dimethylformamide (DMF) as solvent.

[0223] Furthermore, as the pattern becomes more regular and refined, the influence of the aforementioned polymer molecular weight distribution (Mw / Mn) becomes more pronounced. Therefore, in order to obtain a resist composition suitable for fine pattern sizes, a narrow dispersion of Mw / Mn of 1.0 to 2.0 is preferable. If it is within the aforementioned range, there will be fewer low-molecular-weight and high-molecular-weight polymers, and after exposure, there is no risk of foreign matter appearing on the pattern or the pattern shape deteriorating.

[0224] The aforementioned method for synthesizing the polymer may include, for example, a method of polymerizing a monomer given to the aforementioned repeating unit in an organic solvent, adding a free radical polymerization initiator and heating it.

[0225] Specific examples of organic solvents used in polymerization include toluene, benzene, THF, diethyl ether, dialkylene, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), γ-butyrolactone (GBL), etc. Specific examples of the aforementioned polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylpentanonitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, lauryl peroxide, etc. The amount of these initiators added relative to the total monomers to be polymerized is preferably 0.01~25 moles. A reaction temperature of 50~150℃ is ideal, and 60~100℃ is more ideal. A reaction time of 2 to 24 hours is ideal, but from the perspective of production efficiency, 2 to 12 hours is even more ideal.

[0226] The aforementioned polymerization initiator can be added to the aforementioned monomer solution and supplied to the reactor, or the initiator solution can be prepared separately from the aforementioned monomer solution and supplied to the reactor independently. During the standby time, the polymerization reaction may proceed due to free radicals generated from the initiator, resulting in the formation of ultra-high molecular weight polymers. Therefore, from a quality management perspective, it is preferable to prepare the monomer solution and the initiator solution independently and add them dropwise. Acid-destabilized groups already introduced into the monomer can be used directly, and protection or partial protection can be applied after polymerization. Furthermore, to adjust the molecular weight, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol can also be used. In this case, the amount of such chain transfer agents added relative to the total amount of monomers to be polymerized is preferably 0.01~20 mol%.

[0227] When the monomer contains hydroxyl groups, the hydroxyl groups can be replaced with acetal groups such as ethoxyethoxy that are easily deprotected by acid during polymerization. After polymerization, deprotection can be carried out using weak acid and water. Alternatively, the monomers can be replaced with acetyl, methyl, trimethylacetyl, etc., before polymerization and then subjected to alkaline hydrolysis after polymerization.

[0228] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene and other monomers can be added to an organic solvent with a free radical polymerization initiator and heated for polymerization. Alternatively, acetoxystyrene or acetoxyvinylnaphthalene can be used. After polymerization, alkaline hydrolysis can be used to deprotect the acetoxy group to obtain polyhydroxystyrene or hydroxypolyvinylnaphthalene.

[0229] Specific examples of the alkali used in alkaline hydrolysis include ammonia water, triethylamine, etc. Furthermore, the reaction temperature is preferably -20~100℃, more preferably 0~60℃. The reaction time is preferably 0.2~100 hours, more preferably 0.5~20 hours.

[0230] Furthermore, the amount of each monomer in the aforementioned monomer solution can be appropriately set to, for example, the ideal content ratio of the aforementioned repeating unit.

[0231] The polymer obtained by the aforementioned manufacturing method can be used as the final product by the reaction solution obtained by the polymerization reaction, or the powder obtained by the refining steps such as adding the polymer liquid to a poor solvent and obtaining powder by reprecipitation. Considering the viewpoints of work efficiency and quality stability, it is better to use the polymer solution obtained by dissolving the powder obtained by the refining step in the solvent as the final product.

[0232] Specific examples of solvents used at this time include ketones such as cyclohexanone and methyl-2-n-pentyl ketone as described in paragraphs

[0144] to

[0145] of Japanese Patent Application Publication 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, and propylene glycol dimethyl ether. Ethers such as 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, tributyl acetate, tributyl propionate, propylene glycol monotert-butyl ether acetate; lactones such as GBL; alcohols such as diacetone alcohol (DAA); high-boiling-point alcohol solvents such as diethylene glycol, propylene glycol, glycerol, 1,4-butanediol, and 1,3-butanediol; and mixed solvents thereof.

[0233] In the aforementioned polymer solution, a polymer concentration of 0.01 to 30% by mass is ideal, and 0.1 to 20% by mass is even more ideal.

[0234] It is preferable to filter the aforementioned reaction solution and polymer solution using a filter. By filtering, foreign matter and gel that may be the cause of defects can be removed, which is effective in stabilizing the quality.

[0235] The materials of the filters used in the aforementioned filtration process can include fluorocarbon, cellulose, nylon, polyester, and hydrocarbon materials. However, in the filtration step involving chemically amplifying inhibitors, filters made of fluorocarbon (such as Teflon, a registered trademark), polyethylene, polypropylene, or nylon are preferred. The pore size of the filter can be appropriately selected according to the target cleanliness level, but it is preferably below 100 nm, and more preferably below 20 nm. Furthermore, a single filter can be used, or multiple filters can be used in combination. The filtration method can pass the solution through only once, but it is better to circulate the solution and perform multiple filtrations. The filtration steps can be performed in any order and number of times during the polymer manufacturing process, but it is better to filter the reaction solution after the polymerization reaction, the polymer solution, or both.

[0236] [Chemical Amplification Inhibitor Composition] [(A) Base Polymer] The chemical amplification inhibitor composition of the present invention contains a base polymer containing the aforementioned polymer as component (A).

[0237] The aforementioned polymer may be used alone, or two or more polymers with different composition ratios, Mw and / or Mw / Mn ratios may be used in combination. Also, (A) the base polymer may contain hydrides of ring-opening metathesis polymers in addition to the aforementioned polymers. For such polymers, the one disclosed in Japanese Patent Application Publication No. 2003-66612 may be used.

[0238] [(B) Quenching Agent] The chemical amplification inhibitor composition of the present invention may also contain a quenching agent as component (B). Furthermore, in the present invention, the quenching agent refers to a material used to form the desired pattern by capturing the acid generated by the photoacid generator in the chemical amplification inhibitor composition and preventing the acid from diffusing to the unexposed area.

[0239] (B) Specific examples of quenching agents include onium salts represented by formula (1) or (2). [Chemistry 162]

[0240] In formula (1), Rq1 is a hydrogen atom, or may contain a hydrocarbon group with 1 to 40 carbon atoms of heteroatoms, except where the hydrogen atom bonded to the carbon atom at the α position of the sulfonyl group is replaced by a fluorine atom or a fluoroalkyl group. In formula (2), Rq2 is a hydrogen atom, or may contain a hydrocarbon group with 1 to 40 carbon atoms of heteroatoms.

[0241] Rq1 represents hydrocarbon groups with 1 to 40 carbon atoms. Specifically, these include alkyl groups with 1 to 40 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, n-pentyl, tripentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norcamphenyl, tricyclo[5.2.1.02,6]decyl, and adamantyl; and aryl groups with 6 to 40 carbon atoms such as phenyl, naphthyl, and anthracene. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. The -CH2- portion of the aforementioned hydrocarbon group can also be replaced by a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may also contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulfonolactone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0242] Rq2 represents a hydrocarbon group. In particular, in addition to the substituents shown in the specific examples of Rq1, fluorinated saturated hydrocarbon groups such as trifluoromethyl and trifluoroethyl, fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl can also be listed.

[0243] Specific examples of the anions of onium salts represented by formula (1) are listed below, but are not limited to these. [Chemistry 163]

[0244] [Chemical 164]

[0245] [Chemistry 165]

[0246] Specific examples of the anions of onium salts represented by formula (2) are listed below, but are not limited to these. [Chemistry 166]

[0247] [Chemistry 167]

[0248] [Chemical 168]

[0249] In formulas (1) and (2), Mq+ is a ium cation. Preferably, the ium cation is represented by strontium cation (cation-1), monium cation (cation-2), or ammonium cation (cation-3). [Chemical 169]

[0250] In formulas (cation-1) and (cation-2), Rct1 to Rct5 are each independently a halogen atom, or may contain a hydrocarbon group with 1 to 30 carbon atoms of heteroatoms.

[0251] Specific examples of halogen atoms represented by Rct1~Rct5 include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.

[0252] Rct1~Rct5 can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include alkyl groups with 1 to 30 carbons such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, dibutyl, and tributyl; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norcamphenyl, and adamantyl; alkenyl groups with 2 to 30 carbons such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclohexenyl groups with 3 to 30 carbons such as cyclohexenyl; aryl groups with 6 to 30 carbons such as phenyl, naphthyl, and thiophene; aralkyl groups with 7 to 30 carbons such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these, with aryl being preferred. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. The -CH2- portion of the aforementioned hydrocarbon group can also be replaced by a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulcinolone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0253] Furthermore, Rct1 and Rct2 can also bond to each other and form a ring together with the sulfur atoms they are bonded to. Specific examples of the aforementioned ring structure can be shown in the following formula. [Chemistry 170] In the formula, the chain line represents the atomic bond with Rct3.

[0254] Specific examples of strontium cations represented by formula (cation-1) are listed below, but are not limited to these. [Chem. 171]

[0255] [Chemical 172]

[0256] [Chemistry 173]

[0257] [Chemical 174]

[0258] [Chemical 175]

[0259] [Chemistry 176]

[0260] [Chemistry 177]

[0261] [Chemistry 178]

[0262] [Chemistry 179]

[0263] [Chemical 180]

[0264] [Chemical 181]

[0265] [Chemical 182]

[0266] [Chemical 183]

[0267] [Chemical 184]

[0268] [Chemical 185]

[0269] [Chemistry 186]

[0270] [Chemistry 187]

[0271] [Chemistry 188]

[0272] [Chemistry 189]

[0273] [Chemical 190]

[0274] [Chemistry 191]

[0275] [Chemistry 192]

[0276] [Chemistry 193]

[0277] [Chemical 194]

[0278] [Chemical 195]

[0279] [Chemistry 196]

[0280] [Chemistry 197]

[0281] Examples of phosphate cations represented by formula (cation-2) are listed below, but are not limited to these. [Chemistry 198]

[0282] [Chemical 199]

[0283] In formula (cation-3), Rct6 to Rct9 are each independently an hydrocarbon with 1 to 40 carbon atoms, which may also contain heteroatoms. Furthermore, Rct6 and Rct7 may bond to each other and form a ring together with the nitrogen atoms they are bonded to. Specific examples of the aforementioned hydrocarbons are the same as those exemplified by the hydrocarbons represented by Rct1 to Rct5 in the descriptions of formulas (cation-1) and (cation-2).

[0284] Specific examples of ammonium cations represented by formula (cation-3) are listed below, but are not limited to these. [Chem. 200]

[0285] Specific examples of onium salts represented by formula (1) or (2) include any combination of the aforementioned anions and cations. Furthermore, such onium salts can be easily prepared by ion exchange reactions using known organic chemical methods. For example, Japanese Patent Application Publication No. 2007-145797 can be consulted regarding ion exchange reactions.

[0286] The onium salt represented by formula (1) or (2) functions as a quencher in the chemical amplification inhibitor composition of the present invention. This is because the relative anions of the aforementioned onium salts are conjugate bases of weak acids. The weak acid referred to here is an acid that exhibits an acidity that cannot deprotect the acid unstable groups of the units containing acid unstable groups contained in the base polymer. The onium salt represented by formula (1) or (2) functions as a quencher when used in combination with a conjugate base of a strong acid such as an α-fluorinated sulfonic acid as an onium salt-type photoacid generator with a relative anion. In other words, when onium salts that produce strong acids such as α-fluorinated sulfonic acids are mixed with onium salts that produce weak acids such as unfluorinated sulfonic acids and carboxylic acids, the strong acid generated from the photoacid generator by high-energy radiation will collide with the unreacted onium salt containing a weak acid anion, resulting in salt exchange and the release of the weak acid, thus producing an onium salt containing a strong acid anion. In this process, the strong acid is exchanged for a weak acid with lower catalytic ability, thus macroscopically deactivating the acid and enabling control of acid diffusion.

[0287] Furthermore, (B) the quenching agent may also be an onium salt having strontium cation and benzene oxide anion sites in the same molecule as described in Japanese Patent No. 6848776, and may also be an onium salt having strontium cation and carboxyl anion sites in the same molecule as described in Japanese Patent No. 6583136, Japanese Patent Application Publication No. 2020-200311, and an onium salt having monium cation and carboxyl anion sites in the same molecule as described in Japanese Patent No. 6274755.

[0288] Here, when the photoacid generator that produces a strong acid is an onium salt, as mentioned above, the strong acid produced by high-energy ray irradiation can be exchanged for a weak acid. However, on the other hand, it is believed that salt exchange through collision between the weak acid produced by high-energy ray irradiation and the unreacted onium salt that produces a strong acid is not easily achieved. This is because onium cations are more likely to form ion pairs with the anions of strong acids.

[0289] When the chemical amplification inhibitor composition of the present invention contains an onium salt represented by formula (1) or (2) as a quencher in (B), its content is ideally 0.1 to 20 parts by mass relative to 80 parts by mass of the base polymer in (A), and even more ideally 0.1 to 10 parts by mass. If the onium salt type quencher in component (B) is within the aforementioned range, the resolution is good and the sensitivity will not decrease significantly, thus it is ideal. The onium salt represented by formula (1) or (2) can be used alone or in combination of two or more.

[0290] The chemical amplification inhibitor composition of the present invention may also contain a nitrogen-containing compound as a (B) quencher. Examples of nitrogen-containing compounds for (B) include first-, second-, or third-order amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Application Publication No. 2008-111103, particularly amine compounds having hydroxyl groups, ether bonds, ester bonds, lactone rings, cyano groups, or sulfonate bonds. Also, compounds such as those described in Japanese Patent Application Publication No. 3790649, which are first- or second-order amines protected by carbamate groups, may also be included. Furthermore, compounds such as those described in Japanese Patent Application Publication No. 2009-109595, which contain an acid-destabilized group within the molecule, may also be included.

[0291] Furthermore, nitrogen-containing compounds may also be strontium sulfonate salts having nitrogen-containing substituents. Such compounds act as quenchers in the unexposed areas, while the exposed areas lose their quenching ability due to neutralization with the acid they generate, thus acting as so-called photodegrading bases. By using photodegrading bases, the contrast between the exposed and unexposed areas can be further enhanced. For example, Japanese Patent Application Laid-Open No. 2009-109595 and Japanese Patent Application Laid-Open No. 2012-46501 may be referenced for photodegrading bases.

[0292] When the chemical amplification inhibitor composition of the present invention contains a nitrogen-containing compound as a (B) quencher, its content is ideally 0.001 to 12 parts by mass relative to 80 parts by mass of the (A) base polymer, and even more ideally 0.01 to 8 parts by mass. The aforementioned nitrogen-containing compound may be used alone or in combination of two or more.

[0293] [(C) Organic Solvent] The chemical amplification inhibitor composition of the present invention may also contain an organic solvent as component (C). The organic solvent (C) may be any solvent that can dissolve the aforementioned components and the components described below, and there are no particular limitations. Specific examples of such organic solvents include ketones such as cyclopentanone, cyclohexanone, and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ketols such as DAA; ethers such as 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, tributyl acetate, tributyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as GBL; and mixtures thereof.

[0294] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA and mixed solvents thereof, which have particularly excellent solubility in the base polymer of component (A), are preferred.

[0295] In the chemical amplification inhibitor composition of the present invention, the content of (C) organic solvent is ideally 200-5000 parts by mass relative to 80 parts by mass of (A) base polymer, and more ideally 400-3500 parts by mass. (C) Organic solvent can be used alone or in combination of two or more.

[0296] [(D) Acid Generating Agent] The chemical amplification inhibitor composition of the present invention may also contain an acid generating agent within the range that does not impair the effects of the present invention. The aforementioned acid generating agent is, for example, a compound that produces acid in response to active light or radiation (photoacid generating agent). The photoacid generating agent is not particularly limited as long as it is a compound that produces acid due to high-energy radiation, but it is preferred that it produces sulfonic acid, amide acid, or methyl acid. Ideal photoacid generating agents include strontium salts, ferric salts, sulfonyldiazomethane, N-sulfonoxyamide, oxime-O-sulfonate type acid generating agents, etc. Specific examples of acid generating agents are described in paragraphs

[0122] to

[0142] of Japanese Patent Application Publication No. 2008-111103.

[0297] Furthermore, it is also ideal to use strontium salts represented by formula (3-1) and ferrous salts represented by formula (3-2) as photoacid generators. [Chemical 201]

[0298] In formulas (3-1) and (3-2), R101 to R105 are each independently a halogen atom, or may contain a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms. Specific examples of the aforementioned halogen atoms and hydrocarbon groups are the same as those exemplified in the descriptions of formulas (cation-1) and (cation-2) regarding the halogen atoms and hydrocarbon groups represented by Rct1 to Rct5. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group may be replaced by a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms. The -CH2- portion of the aforementioned hydrocarbon group may also be replaced by a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, it may contain hydroxyl, fluorine, chlorine, bromine, iodine, cyano, nitro, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulfonate ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl, etc. Furthermore, R101 and R102 can also bond to each other and form a ring together with the sulfur atoms they are bonded to. Specific examples of the rings formed in this case are the same as those shown in the explanation of formula (cation-1) regarding the rings formed by Rct1 and Rct2 bonded to each other and the sulfur atoms they are bonded to.

[0299] The specific example of the strontium salt cation represented by formula (3-1) is the same as the example of the strontium cation represented by formula (cation-1). Also, the specific example of the zirconia salt cation represented by formula (3-2) is the same as the example of the zirconia cation represented by formula (cation-2).

[0300] In formulas (3-1) and (3-2), Xa- is an anion selected from formulas (3A) to (3D). [Chemical Engineering 202]

[0301] In formula (3A), Rfa is a fluorine atom, or may contain a hydrocarbon group with 1 to 40 carbon atoms containing heteroatoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples are the same as those exemplified in the explanation of Rfa1 in formula (3A') described later.

[0302] It is preferable that the anion represented by formula (3A) is represented by formula (3A'). [Chemical 203]

[0303] In formula (3A'), RHF is a hydrogen atom or a trifluoromethyl atom, preferably a trifluoromethyl atom.

[0304] In formula (3A'), Rfa1 can be a hydrocarbon group with 1 to 38 carbon atoms that may also contain heteroatoms. Among the aforementioned heteroatoms, oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms, etc. are more ideal, with oxygen atoms being more ideal. Among the aforementioned hydrocarbon groups, considering the viewpoint of obtaining high resolution during the formation of fine patterns, those with 6 to 30 carbon atoms are particularly preferred.

[0305] Rfa1 indicates that the hydrocarbon group with 1 to 38 carbon atoms can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. Specific examples include alkyl groups with 1 to 38 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecanyl, and icosyl; cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norcamphenyl, norcamphenylmethyl, tricyclodecyl, tetracyclododecyl, tetracyclododecylmethyl, and dicyclohexylmethyl; allyl and 3-cyclohexenyl, unsaturated aliphatic hydrocarbon groups with 2 to 38 carbon atoms; aryl groups with 6 to 38 carbon atoms, such as phenyl, 1-naphthyl, and 2-naphthyl; aralkyl groups with 7 to 38 carbon atoms, such as benzyl and diphenylmethyl; and groups obtained by combining them.

[0306] Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group may be replaced by a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, or halogen atoms. Similarly, the -CH2- portion of the aforementioned hydrocarbon group may be replaced by a group containing heteroatoms such as oxygen atoms, sulfur atoms, or nitrogen atoms. As a result, it may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulfonolactone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc. It is preferable that the aforementioned heteroatom is an oxygen atom. Specific examples of hydrocarbon groups containing heteroatoms include tetrahydrofuranyl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetaminomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-sideoxypropyl, 4-sideoxy-1-adamantyl, 3-sideoxycyclohexyl, etc.

[0307] For details regarding the synthesis of strontium salts containing anions represented by formula (3A'), please refer to Japanese Patent Application Publication Nos. 2007-145797, 2008-106045, 2009-7327, and 2009-258695. Furthermore, strontium salts described in Japanese Patent Application Publication Nos. 2010-215608, 2012-41320, 2012-106986, and 2012-153644 are also suitable for use.

[0308] Specific examples of anions represented by formula (3A) are listed below, but are not limited to these. Also, in the following formula, Ac is acetyl. [Chem. 204]

[0309] [Chemical 205]

[0310] [Chemical 206]

[0311] [Chemical 207]

[0312] In formula (3B), Rfb1 and Rfb2 are each independently a fluorine atom, or may contain heteroatoms and be a hydrocarbon group with 1 to 40 carbon atoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples are the same as those exemplified by the hydrocarbon group represented by Rfa1 in formula (3A'). Rfb1 and Rfb2 are preferably fluorine atoms or linear fluorinated alkyl groups with 1 to 4 carbon atoms. Furthermore, Rfb1 and Rfb2 may also be bonded to each other and form a ring together with the group they are bonded to (-CF2-SO2-N--SO2-CF2-), in which case the group obtained by the mutual bonding of Rfb1 and Rfb2 is preferably fluorinated ethyl or fluorinated propyl.

[0313] In formula (3C), Rfc1, Rfc2, and Rfc3 are each independently a fluorine atom, or may contain heteroatoms and be a hydrocarbon group with 1 to 40 carbon atoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples are the same as those exemplified by the hydrocarbon group represented by Rfa1 in formula (3A'). Rfc1, Rfc2, and Rfc3 are preferably fluorine atoms or linear fluorinated alkyl groups with 1 to 4 carbon atoms. Furthermore, Rfc1 and Rfc2 may also be bonded to each other and form a ring together with the group they are bonded to (-CF2-SO2-C--SO2-CF2-), in which case the group obtained by the mutual bonding of Rfc1 and Rfc2 is preferably fluorinated ethyl or fluorinated propyl.

[0314] In formula (3D), Rfd is a hydrocarbon group with 1 to 40 carbon atoms, which may also contain heteroatoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples are the same as those exemplified by the hydrocarbon group represented by Rfa1 in formula (3A').

[0315] For the synthesis of strontium salts containing anions represented by formula (3D), please refer to Japanese Patent Application Publication No. 2010-215608 and Japanese Patent Application Publication No. 2014-133723.

[0316] Specific examples of anions represented by formula (3D) are listed below, but are not limited to these. [Chemistry 208]

[0317] [Chemical 209]

[0318] Furthermore, the photoacid generator containing the anion represented by formula (3D) has no fluorine atom at the α-position of the sulfonium group, but has two trifluoromethyl groups at the β-position, thus possessing sufficient acidity to cleave the acid-destabilized groups in the base polymer. Therefore, it can be used as a photoacid generator.

[0319] Photogenic acid generators should also be represented by the following formula (4). [Chemical 210]

[0320] In formula (4), R201 and R202 are each independently a hydrocarbon group with 1 to 30 carbon atoms, which may also contain heteroatoms. R203 is an extended hydrocarbon group with 1 to 30 carbon atoms, which may also contain heteroatoms. Furthermore, any two of R201, R202, and R203 may bond to each other and form a ring together with the sulfur atoms they are bonded to. In this case, the specific example of the aforementioned ring is the same as the example shown in the explanation of formula (cation-1) of the ring in which Rct1 and Rct2 are bonded to each other and can form a ring together with the sulfur atoms they are bonded to.

[0321] R201 and R202 represent hydrocarbon groups with 1 to 30 carbon atoms that can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include alkyl groups with 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, n-pentyl, tripentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornel, oxanorbornel, and tricyclic [5.2.1.02,6]. Cyclic saturated hydrocarbon groups with 3 to 30 carbon atoms, such as decyl and adamantyl; aryl groups with 6 to 30 carbon atoms, such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, dibutylphenyl, tributylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, dibutylnaphthyl, tributylnaphthyl, anthracene; and groups obtained by combining them. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. The -CH2- portion of the aforementioned hydrocarbon group can also be replaced by a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulcinolone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0322] R203 indicates that the hydrocarbon group with 1 to 30 carbon atoms can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, and heptadecane-1,17-diyl. Alkyl groups with 1 to 30 carbon atoms; cyclopentanediyl, cyclohexanediyl, norcamphenediyl, adamantanediyl, and other cyclic saturated alkyl groups with 3 to 30 carbon atoms; phenyl groups, methylphenyl groups, ethylphenyl groups, n-propylphenyl groups, isopropylphenyl groups, n-butylphenyl groups, isobutylphenyl groups, dibutylphenyl groups, tributylphenyl groups, naphthyl groups, methyl naphthyl groups, ethyl naphthyl groups, n-propyl naphthyl groups, isopropyl naphthyl groups, n-butyl naphthyl groups, isobutyl naphthyl groups, dibutyl naphthyl groups, tributyl naphthyl groups, and other aryl groups with 6 to 30 carbon atoms; and groups obtained by combining these groups. Furthermore, some or all of the hydrogen atoms in the aforementioned alkyl group can be replaced by a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms. Similarly, the -CH2- portion of the aforementioned alkyl group can also be replaced by a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. This can result in the presence of hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone, sulfonate, carboxylic anhydride (-C(=O)-OC(=O)-), or haloalkyl groups. Oxygen atoms are preferred as the aforementioned heteroatom.

[0323] In formula (4), L1 is a single bond, an ether bond, or may contain a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples are the same as those exemplified by the hydrocarbon group represented by R203.

[0324] In formula (4), Xa, Xb, Xc and Xd are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl atom. However, at least one of Xa, Xb, Xc and Xd is a fluorine atom or a trifluoromethyl atom.

[0325] In formula (4), k is an integer from 0 to 3.

[0326] The photoacid generator represented by formula (4) is preferably represented by formula (4'). [Chemical 211]

[0327] In formula (4'), L1 is as described above. Xe is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R301, R302, and R303 are each independently a hydrocarbon group with 1 to 20 carbon atoms, which may also contain heteroatoms. The aforementioned hydrocarbon groups can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples are the same as those exemplified by the hydrocarbon group represented by Rfa1 in formula (3A'). x and y are each independently an integer from 0 to 5. z is an integer from 0 to 4.

[0328] The specific example of the photoacid generator represented by formula (4) is the same as the example of the photoacid generator represented by formula (2) in Japanese Patent Application Publication No. 2017-26980.

[0329] Among the aforementioned photoacid generators, those containing anions represented by formula (3A') or (3D) exhibit low acid diffusion and excellent solubility in solvents, making them particularly ideal. Furthermore, those represented by formula (4') exhibit extremely low acid diffusion, making them particularly ideal.

[0330] Also, other acid-generating agents can be represented by strontium and ferric salts containing anions with iodine-substituted aromatic rings, as shown in formulas (5-1) or (5-2). [Chem. 212]

[0331] In equations (5-1) and (5-2), p is 1, 2, or 3. q and r are integers that satisfy 1≦q≦5, 0≦r≦3, and 1≦q+r≦5. q being 1, 2, or 3 is ideal, with 2 or 3 being even more ideal. r being 0, 1, or 2 is preferred.

[0332] In formulas (5-1) and (5-2), L11 is a single bond, ether bond, or ester bond, or may contain a saturated alkyl group with 1 to 6 carbon atoms of ether or ester bond. The aforementioned saturated alkyl group may be linear, branched, or cyclic.

[0333] In formulas (5-1) and (5-2), L12 is a single bond or a divalent linkage with 1 to 20 carbon atoms when p is 1, and a (p+1) valent linkage with 1 to 20 carbon atoms when p is 2 or 3. The linkage may also contain oxygen atoms, sulfur atoms or nitrogen atoms.

[0334] In formulas (5-1) and (5-2), R401 is a hydroxyl, carboxyl, fluorine, chlorine, bromine, or amino group, or may contain a fluorine, chlorine, bromine, hydroxyl, amino, or ether bond of a hydrocarbon group with 1 to 20 carbon atoms, a hydrocarbon oxygen group with 1 to 20 carbon atoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms, or a hydrocarbon sulfonyl group with 1 to 20 carbon atoms, or -N(R401A)(R401B), -N(R401C)-C(=O)-R401D or -N(R401C)-C(=O)-O-R401D. R401A and R401B are each independently a hydrogen atom or a saturated hydrocarbon group with 1 to 6 carbon atoms. R401C is a hydrogen atom or a saturated hydrocarbon group with 1 to 6 carbon atoms, and may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxygen group with 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group with 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyl group with 2 to 6 carbon atoms. R401D is an aliphatic hydrocarbon group with 1 to 16 carbon atoms, an aryl group with 6 to 14 carbon atoms, or an aralkyl group with 7 to 15 carbon atoms, and may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxygen group with 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group with 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyl group with 2 to 6 carbon atoms. The aforementioned aliphatic hydrocarbon groups can be saturated or unsaturated, and can be linear, branched, or cyclic. The aforementioned hydrocarbon groups, hydrocarbon oxygen groups, hydrocarbon carbonyl groups, hydrocarbon oxycarbonyl groups, hydrocarbon carbonyl groups, and hydrocarbon sulfonyl groups can be linear, branched, or cyclic. When p and / or r are 2 or more, each R401 can be the same or different from the others.

[0335] Among these, R401 is preferably a hydroxyl group, -N(R401C)-C(=O)-R401D, -N(R401C)-C(=O)-O-R401D, a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group, etc.

[0336] In formulas (5-1) and (5-2), Rf11 to Rf14 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one of them is a fluorine atom or a trifluoromethyl group. Furthermore, Rf11 and Rf12 can also combine to form a carbonyl group. It is particularly preferred that both Rf13 and Rf14 are fluorine atoms.

[0337] In formulas (5-1) and (5-2), R402 to R406 are each independently a halogen atom, or may contain heteroatoms and have 1 to 20 carbon atoms in a hydrocarbon group. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples are the same as those given for the hydrocarbon groups represented by Rct1 to Rct5 in the descriptions of formulas (cation-1) and (cation-2). Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group may be replaced by hydroxyl, carboxyl, halogen, cyano, nitro, mercapto, sulfonyl lactone ring, sulfonyl, or strontium salt-containing groups, and part of the -CH2- group in the aforementioned hydrocarbon group may be replaced by ether, ester, carbonyl, amide, carbonate, or sulfonate bonds. Furthermore, R402 and R403 may also bond to each other and form a ring together with the sulfur atoms they are bonded to. The specific examples of the aforementioned rings are the same as those in the explanation of formula (cation-1) for the rings formed by Rct1 and Rct2 being bonded to each other and together with the sulfur atoms they are bonded to.

[0338] The specific example of the strontium salt cation represented by formula (5-1) is the same as the example of the strontium cation represented by formula (cation-1). Also, the specific example of the zirconia salt cation represented by formula (5-2) is the same as the example of the zirconia cation represented by formula (cation-2).

[0339] Specific examples of onium salt anions represented by formula (5-1) or (5-2) are listed below, but are not limited to these. [Chemistry 213]

[0340] [Chemical 214]

[0341] [Chemical 215]

[0342] [Chemical 216]

[0343] [Chemical 217]

[0344] [Chemical 218]

[0345] [Chemical 219]

[0346] [Chemical 220]

[0347] [Chemical 221]

[0348] [Chemical 222]

[0349] [Chemical 223]

[0350] [Chemical 224]

[0351] [Chemical 225]

[0352] [Chemical 226]

[0353] [Chemical 227]

[0354] [Chemical 228]

[0355] [Chemical 229]

[0356] [Chemical 230]

[0357] [Chemical 231]

[0358] [Chemical 232]

[0359] [Chemistry 233]

[0360] [Chemistry 234]

[0361] When the chemical amplification inhibitor composition of the present invention contains the acid-generating agent (D), its content is ideally 0.1 to 40 parts by mass relative to 80 parts by mass of the base polymer (A), and even more ideally 0.5 to 20 parts by mass. If the amount of acid-generating agent added in component (D) is within the aforementioned range, the resolution is good, and there is no risk of foreign matter occurring after the inhibitor film is developed or peeled off, which is ideal. The acid-generating agent (D) can be used alone or in combination of two or more.

[0362] [(E) Surfactant] The chemical amplification inhibitor composition of the present invention may further contain a surfactant as component (E). The surfactant (E) is preferably a surfactant that is insoluble or poorly soluble in water but soluble in alkaline developing solution, or a surfactant that is insoluble or poorly soluble in both water and alkaline developing solution. Such surfactants can be referred to in Japanese Patent Application Publication Nos. 2010-215608 and 2011-16746.

[0363] Surfactants that are insoluble or poorly soluble in water and alkaline developing solutions are preferably those listed in the aforementioned publication, such as FC-4430 (manufactured by 3M), surflon (registered trademark) S-381 (manufactured by AGC Seimichemical), OLFINE (registered trademark) E1004 (manufactured by Nissin Chemical Industry), KH-20, KH-30 (manufactured by AGC Seimi Chemical), and oxacyclobutane ring-opening polymers represented by the following formula (surf-1). [Chemical 235]

[0364] Here, R, Rf, A, B, C, m, n are irrelevant to the foregoing description and only apply to formula (surf-1). R is an aliphatic group with 2 to 5 carbon atoms in a 2 to 4-valent configuration. Regarding the aforementioned aliphatic groups, divalent groups include ethylenyl, 1,4-butylenyl, 1,2-propylenyl, 2,2-dimethyl-1,3-propylenyl, 1,5-pentylenyl, etc., while trivalent or tetravalent groups include the following. [Chemical 236] In the formula, the chain lines represent atomic bonds, each being a substructure derived from glycerol, trimethylolethane, trimethylolpropane, and neopentyl tetrol.

[0365] Among these, 1,4-endobutyl and 2,2-dimethyl-1,3-endopropyl are preferred.

[0366] Rf is trifluoromethyl or pentafluoroethyl, preferably trifluoromethyl. m is an integer from 0 to 3, n is an integer from 1 to 4, and the sum of n and m is the valence of R, which is an integer from 2 to 4. A is 1. B is an integer from 2 to 25, preferably an integer from 4 to 20. C is an integer from 0 to 10, preferably 0 or 1. Furthermore, the arrangement of the constituent units in formula (surf-1) is not specified; they can be block bonds or random bonds. For details on the manufacture of surfactants based on partially fluorinated oxyheterocyclic butane ring-opening polymers, please refer to the specification of US Patent No. 5,650,483, etc.

[0367] Surfactants that are insoluble or sparingly soluble in water but soluble in alkaline developer can reduce water penetration and leaching when ArF wetted photolithography is used without a resist protective film. This is useful for inhibiting the leaching of water-soluble components from the resist film and for reducing damage to the exposure equipment. Furthermore, they are soluble in alkaline aqueous solutions after exposure or post-exposure baking (PEB) and are less likely to become foreign matter causing defects. Such surfactants, which are polymeric surfactants with properties of being insoluble or sparingly soluble in water but soluble in alkaline developer, are also called hydrophobic resins. Those with high water repellency, which enhances hydrophobic properties, are particularly desirable.

[0368] Specific examples of such polymeric surfactants include those containing at least one repeating unit selected from formulas (6A) to (6E). [Chemical 237]

[0369] In formulas (6A) to (6E), RB is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. W1 is -CH2-, -CH2CH2-, -O-, or two separate -H groups. Rs1 is each independently a hydrogen atom or a hydrocarbon group with 1 to 10 carbon atoms. Rs2 is a single bond or a straight-chain or branched hydrocarbon group with 1 to 5 carbon atoms. Rs3 is each independently a hydrogen atom, a hydrocarbon group with 1 to 15 carbon atoms, a fluorinated hydrocarbon group, or an acid-indeterminate group. When Rs3 is a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group may be inserted between carbon-carbon bonds. Rs4 is a (u+1) valence hydrocarbon group or a fluorinated hydrocarbon group with 1 to 20 carbon atoms. u is an integer from 1 to 3. Rs5 is each independently a hydrogen atom or a group represented by -C(=O)-O-Rsa. Rsa is a fluorinated hydrocarbon group with 1 to 20 carbon atoms. Rs6 is a hydrocarbon group or fluorinated hydrocarbon group with 1 to 15 carbon atoms, and an ether bond or carbonyl group may be inserted between its carbon-carbon bonds.

[0370] The hydrocarbon group represented by Rs1 with 1 to 10 carbon atoms is preferably a saturated hydrocarbon group, and can be any of the following: straight-chain, branched, or cyclic. Specific examples include alkyl groups with 1 to 10 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; and cyclic saturated hydrocarbon groups with 3 to 10 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornel. Among these, those with 1 to 6 carbon atoms are preferred.

[0371] It is ideal for the alkyl group represented by Rs2 to be a saturated alkyl group, which can be any of the following: straight-chain, branched, or cyclic. Specific examples include methylene, ethyl alkyl, propyl alkyl, butyl alkyl, and pentyl alkyl.

[0372] The hydrocarbon group represented by Rs3 or Rs6 can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include saturated hydrocarbon groups, alkenyl groups, alkynyl groups, and other aliphatic unsaturated hydrocarbon groups, but saturated hydrocarbon groups are preferred. Specific examples of the aforementioned saturated hydrocarbon groups include those represented by Rs1, as well as undecayl, dodecyl, tridecayl, tetradecayl, and decadecyl groups. Specific examples of fluorinated hydrocarbon groups represented by Rs3 or Rs6 are groups in which one or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbon group are replaced by fluorine atoms. As mentioned above, ether bonds or carbonyl groups can also be inserted between these carbon-carbon bonds.

[0373] Specific examples of acid-indeterminate groups represented by Rs3 include groups represented by the aforementioned formulas (AL-3) to (AL-5), trialkylsilyl groups in which each alkyl group has 1 to 6 carbon atoms, and alkyl groups containing side oxygen atoms in which each alkyl group has 4 to 20 carbon atoms.

[0374] Rs4 represents a (u+1) valence hydrocarbon group or fluorinated hydrocarbon group, which can be straight-chain, branched, or cyclic. Specific examples include groups obtained by removing u hydrogen atoms from the aforementioned hydrocarbon group or fluorinated hydrocarbon group.

[0375] It is preferable that the fluorinated hydrocarbon group represented by Rsa is saturated, and it can be any of the following: straight-chain, branched, or cyclic. Specific examples include those in which some or all of the hydrogen atoms of the aforementioned hydrocarbon group are replaced by fluorine atoms, such as trifluoromethyl, 2,2,2-trifluoroethyl, 3,3,3-trifluoro-1-propyl, 3,3,3-trifluoro-2-propyl, 2,2,3,3-tetrafluoropropyl, 1,1,1,3,3,3-hexafluoroisopropyl, 2,2,3,3,4,4,4-heptafluorobutyl, 2,2,3,3,4,4,5,5-octafluoropentyl, 2,2,3,3,4,4,5,5,6,6,7,7-dodecylheptyl, 2-(perfluorobutyl)ethyl, 2-(perfluorohexyl)ethyl, 2-(perfluorooctyl)ethyl, 2-(perfluorodecyl)ethyl, etc.

[0376] Specific examples of repeating units represented by any of equations (6A) to (6E) are listed below, but are not limited to these. Also, in the following equations, RB is as described above. [Chemistry 238]

[0377] [Chemistry 239]

[0378] [Chemical 240]

[0379] [Chemistry 241]

[0380] [Chemistry 242]

[0381] The aforementioned polymeric surfactant may also contain other repeating units besides those represented by formulas (6A) to (6E). Specific examples of other repeating units include repeating units obtained from methacrylic acid, α-trifluoromethacrylic acid derivatives, etc. In polymeric surfactants, it is ideal for the content of repeating units represented by formulas (6A) to (6E) to be 20 mol% or more of all repeating units, more preferably 60 mol% or more, and more preferably 100 mol%.

[0382] For the aforementioned polymeric surfactants, a Mw of 1,000 to 500,000 is more ideal, and 3,000 to 100,000 is even more ideal. A Mw / Mn ratio of 1.0 to 2.0 is more ideal, and 1.0 to 1.6 is even more ideal.

[0383] A method for synthesizing the aforementioned polymeric surfactants includes, for example, a monomer containing unsaturated bonds, provided with repeating units represented by formulas (6A) to (6E), and other repeating units as needed, in an organic solvent, with the addition of a free radical initiator and heating, to polymerize it. Specific examples of organic solvents used in polymerization include toluene, benzene, THF, diethyl ether, and dialkylene. Specific examples of polymerization initiators include AIBN, 2,2'-azobis(2,4-dimethylpentanonitrile), dimethyl 2,2-azobis(2-methylpropionic acid), benzoyl peroxide, and lauryl peroxide. A reaction temperature of 50–100°C is preferred. A reaction time of 4–24 hours is preferred. Acid-destabilized groups already introduced into the monomer can be used directly, and protection or partial protection can be applied after polymerization.

[0384] When synthesizing the aforementioned polymeric surfactant, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol can be used to adjust the molecular weight. In this case, it is preferable that the amount of such chain transfer agent added is 0.01 to 10 mol% relative to the total moles of the monomers to be polymerized.

[0385] When the chemical amplification inhibitor composition of the present invention contains (E) surfactant, its content is ideally 0.1 to 50 parts by mass relative to 80 parts by mass of (A) base polymer, and more ideally 0.5 to 10 parts by mass. If the content of (E) surfactant is 0.1 parts by mass or more, the retreat contact angle between the inhibitor film surface and water is sufficiently increased; if it is 50 parts by mass or less, the dissolution rate of the inhibitor film surface to the developer is low, which can sufficiently ensure the height of the formed fine pattern. (E) surfactant can be used alone or in combination of two or more.

[0386] [(F) Dissolution Inhibitor] The chemical amplification inhibitor composition of the present invention may further contain a dissolution inhibitor as the (F) component. When the chemical amplification inhibitor composition of the present invention is positive, by incorporating a dissolution inhibitor, the difference in dissolution rate between the exposed and unexposed areas can be increased, thereby improving the resolution.

[0387] Specific examples of the aforementioned dissolution inhibitors may be listed as: compounds in which the hydrogen atom of the phenolic hydroxyl group of a compound having a molecular weight preferably of 100 to 1,000, more preferably 150 to 800, and containing two or more phenolic hydroxyl groups in the molecule is replaced by an acid-destabilizing group in a proportion of 0 to 100 moles over the whole; or compounds in which the hydrogen atom of the carboxyl group of a compound containing a carboxyl group is replaced by an acid-destabilizing group in an average proportion of 50 to 100 moles over the whole. Specifically, examples may be listed as compounds in which the hydrogen atoms of the hydroxyl and carboxyl groups of bisphenol A, phenyl phenol, phenolphthalein, cresol phenolic varnish, naphtholic acid, adamantane carboxylic acid, and cholic acid are replaced by acid-destabilizing groups, such as those described in paragraphs

[0155] to

[0178] of Japanese Patent Application Publication No. 2008-122932.

[0388] When the chemical amplification inhibitor composition of the present invention contains a (F) dissolution inhibitor, its content is ideally 0 to 50 parts by mass relative to 80 parts by mass of the (A) base polymer, and more ideally 5 to 40 parts by mass. The (F) dissolution inhibitor can be used alone or in combination of two or more.

[0389] [(G) Other Components] The chemical amplification inhibitor composition of the present invention may also contain compounds that produce acid due to acid decomposition (acid-increasing compounds), organic acid derivatives, fluorinated alcohols, water-repellent enhancers, etc., as other components in (G). The aforementioned acid-increasing compounds can be referred to in Japanese Patent Application Publication No. 2009-269953 or Japanese Patent Application Publication No. 2010-215608. When containing the aforementioned acid-increasing compounds, their content is ideally 0-5 parts by mass relative to 80 parts by mass of the (A) base polymer, and more ideally 0-3 parts by mass. If the content is too high, it is difficult to control acid diffusion, which may lead to degradation of resolution and pattern shape. The aforementioned organic acid derivatives and fluorinated alcohols can be referred to in Japanese Patent Application Publication No. 2009-269953 or Japanese Patent Application Publication No. 2010-215608.

[0390] The aforementioned water-repellent enhancer can be used in immersion photolithography without a topcoat. The aforementioned water-repellent enhancer is preferably a polymer containing fluorinated alkyl groups, or a polymer with a specific structure containing 1,1,1,3,3,3-hexafluoro-2-propanol residues, as exemplified in Japanese Patent Application Publication Nos. 2007-297590 and 2008-111103. The aforementioned water-repellent enhancer needs to be soluble in alkaline developing solutions and organic solvent developing solutions. The aforementioned specific water-repellent enhancer containing 1,1,1,3,3,3-hexafluoro-2-propanol residues has good solubility in developing solutions. Regarding water-repellent enhancers, polymers containing repeating units containing amine groups or amine salts are highly effective in preventing acid evaporation in PEB and preventing poor opening of the hole pattern after development. When the chemical amplification inhibitor composition of the present invention contains the aforementioned water-repellent enhancer, its content is ideally 0 to 20 parts by mass relative to 80 parts by mass of the (A) base polymer, and even more ideally 0.5 to 10 parts by mass.

[0391] [Pattern Forming Method] When the chemical amplifying resist composition of the present invention is used in the manufacture of various integrated circuits, it can be applied using known lithography techniques. For example, a pattern forming method may include the following steps: forming a resist film on a substrate using the aforementioned chemical amplifying resist composition; exposing the aforementioned resist film to high-energy radiation; and developing the aforementioned exposed resist film using a developing solution.

[0392] First, the chemically amplified resist composition of the present invention is coated onto a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflective film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) using appropriate coating methods such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor blade coating, so that the coating film thickness is 0.01~2.0μm. It is then pre-baked on a hot plate, preferably at 60~150°C for 10 seconds to 30 minutes, more preferably at 80~120°C for 30 seconds to 20 minutes, to form a resist film.

[0393] Next, the aforementioned resist film is exposed using high-energy rays. Examples of such high-energy rays include ultraviolet light, far-ultraviolet light, EB, EUV with wavelengths of 3-15 nm, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation. When using ultraviolet light, far-ultraviolet light, EUV, X-rays, soft X-rays, excimer laser light, gamma rays, or synchrotron radiation, irradiation is performed directly or using a mask to form the desired pattern, with an exposure dose preferably of approximately 1-200 mJ / cm², more preferably approximately 10-100 mJ / cm². When using EB, the aforementioned high-energy rays are applied directly or using a mask to form the desired pattern, with an exposure dose preferably of approximately 0.1-100 μC / cm², more preferably approximately 0.5-50 μC / cm². The chemical amplification inhibitor composition of this invention is particularly suitable for micro-patterning of high-energy rays such as ArF excimer laser light with a wavelength of 193nm, KrF excimer laser light with a wavelength of 248nm, EB or EUV, X-rays, soft X-rays, gamma rays or synchrotron radiation with wavelengths of 3~15nm.

[0394] After exposure, PEB can be performed on a hot plate, preferably at 60~150℃ for 10 seconds to 30 minutes, and more preferably at 80~120℃ for 30 seconds to 20 minutes.

[0395] After exposure or PEB, use a developer solution of 0.1-10% by mass, preferably 2-5% by mass, of an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide, and perform development for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, using conventional methods such as dip, puddle, or spray. The exposed areas dissolve in the developer solution, while the unexposed areas do not dissolve, forming the desired positive pattern on the substrate.

[0396] Alternatively, an organic solvent developer can be used instead of the aforementioned alkaline aqueous solution to obtain a negative pattern. Specific examples of developers used in this case include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methyl acetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, methyl valerate, methyl valerate, methyl crotonate, and crotonic acid. Ethyl propionate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenyl acetate, benzyl formate, phenyl ethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents can be used alone or in mixtures of two or more.

[0397] Rinsing may also be performed at the end of development. It is preferable to use a solvent that is miscible with the developer and does not dissolve the resist film. Such solvents are preferably alcohols with 3 to 10 carbon atoms, ether compounds with 8 to 12 carbon atoms, alkanes, alkenes, alkynes, or aromatic solvents with 6 to 12 carbon atoms.

[0398] Specific examples of the aforementioned alcohols with 3 to 10 carbon atoms include n-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tributanol, 1-pentanol, 2-pentanol, 3-pentanol, neopentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-Dimethyl-1-butanol, 3,3-Dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol, etc.

[0399] Specific examples of the aforementioned ether compounds with 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, didi-dibutyl ether, di-n-pentyl ether, diisopentyl ether, didi-dipentyl ether, didi-dipentyl ether, di-n-hexyl ether, etc.

[0400] Specific examples of the aforementioned alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, and cyclononane. Specific examples of the aforementioned alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Specific examples of the aforementioned alkynes having 6 to 12 carbon atoms include hexyne, heptyne, and octyne.

[0401] Specific examples of the aforementioned aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tributylbenzene, mesitylene, etc.

[0402] Rinsing can reduce the collapse of resist patterns and the occurrence of defects. Furthermore, rinsing is not necessary, and by not rinsing, the amount of solvent used can be reduced.

[0403] The developed hole and groove patterns can also be shrunk using heat transfer, RELACS, or DSA techniques. A shrinking agent is applied to the hole pattern, and through an acid catalyst, it diffuses from the resist film during baking, causing cross-linking of the shrinking agent on the surface of the resist film. The shrinking agent adheres to the sidewalls of the hole pattern. The baking temperature is preferably 70-180°C, more preferably 80-170°C, and the baking time is preferably 10-300 seconds, removing excess shrinking agent and shrinking the hole pattern. [Example]

[0404] The following examples, embodiments, and comparative examples are provided to specifically illustrate the present invention. The present invention is not limited to the following embodiments. Furthermore, the device used is shown below. • MALDI TOF-MS: Nippon Electronics (Group) Co., Ltd. S3000

[0405] [1] Synthesis of onium salt type monomers [Example 1-1] Synthesis of onium salt type monomer a-1 [Chemical 243]

[0406] (1) The intermediate In-1 was synthesized under nitrogen atmosphere. The starting material SM-1 (37.2 g), triethylamine (18.0 g) and 4-dimethylaminopyridine (1.50 g) were dissolved or suspended in THF (200 g) in a reaction vessel and cooled in an ice bath. Then, a solution of p-styrene sulfonyl chloride (16.4 g) dissolved in THF (50 g) was added dropwise. After the addition, the temperature in the reaction vessel was raised to 50 °C and matured for 6 hours. Then, the reaction solution was cooled, saturated sodium bicarbonate water (100 g) was added and the reaction was stopped. The target product was extracted twice with ethyl acetate (200 g) and subjected to the usual aqueous work-up. After the solvent was distilled off, the product was purified by silica gel chromatography to obtain 45.8 g of intermediate In-1 as an oil (yield 97%).

[0407] (2) Synthesis of intermediate In-2: Under nitrogen atmosphere, intermediate In-1 (45.8 g) was dissolved in THF (200 g). While cooling in an ice bath, 25% sodium hydroxide aqueous solution (15.5 g) was added dropwise. After the addition, the temperature in the reaction vessel was raised to 30°C and matured for 12 hours. After maturation, the reaction solution was cooled, and 20% hydrochloric acid (18.2 g) was added dropwise to stop the reaction. The target product was extracted twice with ethyl acetate (200 g), and a conventional aqueous work-up was performed. After distilling off the solvent, the product was recrystallized with hexane to obtain 37.5 g of white crystalline intermediate In-2 (yield 90%).

[0408] (3) Synthesis of intermediate In-3: Under nitrogen atmosphere, intermediate In-2 (37.5 g), raw material SM-2 (34.8 g), 4-dimethylaminopyridine (1.1 g), and dichloromethane (150 g) were added to a reaction vessel and cooled in an ice bath. The temperature inside the reaction vessel was maintained below 20°C, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (20.1 g) was added directly in powder form. After addition, the temperature was raised to room temperature and matured for 12 hours. After maturation, water (100 g) was added and the reaction was stopped. Aqueous work-up was performed, the solvent was distilled off, diisopropyl ether was added, and recrystallization was carried out to obtain 61.5 g of intermediate In-3 as an oil (yield 89%).

[0409] (4) Synthesis of onium salt monomer a-1: Under nitrogen atmosphere, intermediate In-3 (61.5 g), starting material SM-3 (36.6 g), dichloromethane (200 g), and water (150 g) were added to a reaction vessel. After stirring for 30 minutes, the organic layer was separated and washed with water, followed by concentration under reduced pressure. The concentrate was purified by silica gel chromatography to obtain 71.6 g of the target onium salt monomer a-1 as an oily substance (yield 87%). MALDI TOF-MS: POSITIVE M+461 (equivalent to C18H10F4IS+) NEGATIVE M-766 (equivalent to C18H10F5I2O8S2-)

[0410] [Examples 1-2~1-7] Synthesis of onium salt type monomers a-2~a-7: Using corresponding raw materials and known organic synthesis reactions, onium salt type monomers a-2~PAG monomer a-7 represented by the following formula were synthesized. [Chemical 244]

[0411] [Comparative Examples 1-1 to 1-4] Comparative ononium salt monomers Ca-1 to Ca-4 were synthesized using corresponding starting materials and known organic synthesis reactions, according to the following formulas. [Chemistry 245]

[0412] [2] Synthesis of basic polymers The monomers used in the synthesis of basic polymers, other than monomers a-1 to a-7 and comparative monomers ca-1 to ca-4, are shown below. [Chemistry 246]

[0413] [Chemistry 247]

[0414] [Chemistry 248]

[0415] [Example 2-1] The synthesis of polymer P-1 was carried out under nitrogen atmosphere. In a flask, monomer a-1 (49.5 g), monomer b1-1 (39.7 g), monomer c-1 (11.5 g), V-601 (manufactured by Fujifilm and Koei Tecmo Chemicals Co., Ltd.) 3.67 g, and MEK 139 g were measured to prepare a monomer-polymerization initiator solution. In another flask under nitrogen atmosphere, 46 g of MEK was measured, and the mixture was heated to 80°C while stirring. The aforementioned monomer-polymerization initiator solution was then added dropwise over 4 hours. After the addition was complete, the polymerization solution was maintained at 80°C and stirred for another 2 hours, followed by cooling to room temperature. The obtained polymerization solution was then added dropwise to 3000 g of hexane under vigorous stirring, and the polymer was filtered out. The obtained polymer was washed twice with 600g of hexane and then vacuum dried at 50°C for 20 hours to obtain a white powder, polymer P-1 (yield 96.3g, 96% yield). The Mw of polymer P-1 was 9500, and the Mw / Mn ratio was 1.72. Furthermore, Mw is a converted value of polystyrene obtained using GPC with DMF as a solvent. [Chem. 249]

[0416] [Examples 2-2~2-20, Comparative Examples 2-1~2-10] The polymers P-2~P-20 and comparative polymers CP-1~CP-10 were synthesized by changing the type and blending ratio of each monomer, except that the polymers shown in Tables 1 and 2 were manufactured in the same way as in Example 2-1.

[0417] [Table 1] polymer Unit 1 Import ratio (mol%) Unit 2 Import ratio (mol%) Unit 3 Import ratio (mol%) Unit 4 Import ratio (mol%) Unit 5 Import ratio (mol%) Mw Mw / Mn P-1 a-1 15 b1-1 55 - - c-1 30 - - 9500 1.72 P-2 a-2 15 b1-1 55 - - c-1 30 - - 9600 1.74 P-3 a-3 15 b1-1 55 - - c-1 30 - - 9300 1.73 P-4 a-4 15 b1-1 55 - - c-1 30 - - 9100 1.74 P-5 a-5 15 b1-1 55 - - c-1 30 - - 8900 1.75 P-6 a-6 15 b1-1 55 - - c-1 30 - - 9000 1.76 P-7 a-7 15 b1-1 55 - - c-1 30 - - 9400 1.75 P-8 a-1 15 b1-2 55 - - c-1 30 - - 9300 1.76 P-9 a-1 15 b2-1 55 - - c-1 30 - - 9100 1.74 P-10 a-2 15 b3-1 45 - - c-1 40 - - 8800 1.75 P-11 a-3 10 b1-3 35 b2-1 20 c-2 25 d-1 10 9400 1.74 P-12 a-4 15 b1-1 25 b1-2 25 c-2 35 - - 9300 1.74 P-13 a-5 15 b1-3 50 c-3 25 d-2 10 - - 9200 1.73 P-14 a-6 15 b2-1 25 b3-1 25 c-4 35 - - 9300 1.76 P-15 a-7 10 b1-2 35 b2-1 15 c-2 30 d-3 10 8700 1.74 P-16 a-1 15 b1-1 35 b1-3 15 c-4 35 - - 9500 1.73 P-17 a-2 15 b1-1 25 b3-1 15 c-2 30 d-1 15 9400 1.76 P-18 a-3 20 b1-2 45 c-2 30 d-3 5 - - 9200 1.73 P-19 a-1 5 b1-1 50 c-4 25 d-2 10 d-3 10 9500 1.76 P-20 a-1 15 b1-2 30 b1-3 20 c-2 35 - - 9200 1.75

[0418] [Table 2] polymer Unit 1 Import ratio (mol%) Unit 2 Import ratio (mol%) Unit 3 Import ratio (mol%) Unit 4 Import ratio (mol%) Unit 5 Import ratio (mol%) Mw Mw / Mn CP-1 ca-1 15 b1-1 55 - - c-1 30 - - 9300 1.73 CP-2 ca-2 15 b1-1 55 - - c-1 30 - - 9200 1.75 CP-3 ca-3 15 b1-1 55 - - c-1 30 - - 9000 1.73 CP-4 ca-4 15 b1-1 55 - - c-1 30 - - 8900 1.75 CP-5 ca-1 10 b1-3 35 b2-1 20 c-2 20 d-1 20 9100 1.73 CP-6 ca-2 10 b1-2 35 b2-1 15 c-2 30 d-3 10 9200 1.75 CP-7 ca-3 15 b1-1 35 b1-3 15 c-4 35 - - 9300 1.74 CP-8 ca-4 15 b1-3 50 c-3 25 d-2 10 - - 9400 1.73 CP-9 ca-2 15 b1-1 25 b3-1 15 c-2 30 d-1 15 9100 1.75 CP-10 ca-4 5 b1-1 50 c-4 25 d-2 10 d-3 10 9000 1.74

[0419] [3] Preparation of chemical amplification inhibitor composition [Examples 3-1~3-20, Comparative Examples 3-1~3-10] The predetermined components selected from the base polymers (P-1~P-20) of the present invention, the base polymers for comparison (CP-1~CP-10), the acid generators (PAG-1, PAG-2) and the quenchers (SQ-1~SQ-3, AQ-1) were dissolved in a solvent containing 0.01% by mass of 3M FC-4430 as a surfactant, as shown in Tables 3 and 4 to prepare a solution. The solution was filtered through a 0.2 μm Teflon (registered trademark) type filter to prepare chemical amplification inhibitor compositions (R-1~R-20, CR-1~CR-10).

[0420] [Table 3] inhibitor Composition Basic polymers (parts by weight) Quenching agent (parts by weight) Acid generating agent (parts by weight) Solvent 1 (parts by weight) Solvent 2 (parts by weight) Example 3-1 R-1 P-1(80) SQ-1(8.0) - PGMEA(2200) DAA(900) Example 3-2 R-2 P-2(80) SQ-1(7.8) - PGMEA(2200) DAA(900) Example 3-3 R-3 P-3(80) SQ-1(7.4) - PGMEA(2200) DAA(900) Examples 3-4 R-4 P-4(80) SQ-1(8.0) - PGMEA(2200) DAA(900) Examples 3-5 R-5 P-5(80) SQ-1(8.0) - PGMEA(2200) DAA(900) Examples 3-6 R-6 P-6(80) SQ-1(8.0) - PGMEA(2200) DAA(900) Examples 3-7 R-7 P-7(80) SQ-1(7.8) - PGMEA(2200) DAA(900) Examples 3-8 R-8 P-8(80) SQ-2(8.0) - PGMEA(2200) DAA(900) Examples 3-9 R-9 P-9(80) SQ-2(8.0) - PGMEA(2200) DAA(900) Examples 3-10 R-10 P-10(80) SQ-1(4.0) AQ-1(4.0) - PGMEA(2200) DAA(900) Example 3-11 R-11 P-11(80) SQ-3(7.8) - PGMEA(2200) DAA(900) Example 3-12 R-12 P-12(80) SQ-3(7.6) - PGMEA(2200) DAA(900) Example 3-13 R-13 P-13(80) SQ-1(7.8) - PGMEA(2200) DAA(900) Example 3-14 R-14 P-14(80) SQ-3(8.0) - PGMEA(2200) DAA(900) Example 3-15 R-15 P-15(80) SQ-2(4.0) AQ-1(4.0) PAG-1(10) PGMEA(2200) DAA(900) Example 3-16 R-16 P-16(80) SQ-1(8.2) - PGMEA(2200) DAA(900) Example 3-17 R-17 P-17(80) SQ-1(7.6) - PGMEA(2200) DAA(900) Example 3-18 R-18 P-18(80) SQ-3(8.0) - PGMEA(2200) DAA(900) Example 3-19 R-19 P-19(80) SQ-3(4.0) AQ-1(4.0) PAG-2(15) PGMEA(2200) DAA(900) Example 3-20 R-20 P-20(80) SQ-2(7.6) - PGMEA(2200) DAA(900)

[0421] [Table 4] inhibitor Composition Basic polymers (parts by weight) Quenching agent (parts by weight) Acid generating agent (parts by weight) Solvent 1 (parts by weight) Solvent 2 (parts by weight) Comparative Example 3-1 CR-1 P-1(80) SQ-1(8.0) - PGMEA(2200) DAA(900) Comparative Example 3-2 CR-2 P-2(80) SQ-1(7.8) - PGMEA(2200) DAA(900) Comparative Example 3-3 CR-3 P-3(80) SQ-1(7.8) - PGMEA(2200) DAA(900) Comparative Examples 3-4 CR-4 P-4(80) SQ-1(8.2) - PGMEA(2200) DAA(900) Comparative Examples 3-5 CR-5 P-5(80) SQ-3(7.8) - PGMEA(2200) DAA(900) Comparative Examples 3-6 CR-6 P-6(80) SQ-2(4.0) AQ-1(4.0) PAG-1(10) PGMEA(2200) DAA(900) Comparative Examples 3-7 CR-7 P-7(80) SQ-1(8.2) - PGMEA(2200) DAA(900) Comparative Examples 3-8 CR-8 P-8(80) SQ-2(7.8) - PGMEA(2200) DAA(900) Comparative Examples 3-9 CR-9 P-9(80) SQ-3(7.6) - PGMEA(2200) DAA(900) Comparative Example 3-10 CR-10 P-10(80) SQ-3(4.0) AQ-1(4.0) PAG-2(15) PGMEA(2200) DAA(900)

[0422] In Tables 3 and 4, the solvents, quenchers (SQ-1~SQ-3, AQ-1), and acid generators (PAG-1, PAG-2) are as follows. • Solvents: PGMEA (propylene glycol monomethyl ether acetate), DAA (diacetone alcohol)

[0423] ・Quenching Agents: SQ-1~SQ-3, AQ-1 [Chemical 250]

[0424] ・Acid generating agents: PAG-1, PAG-2 [Chemical 251]

[0425] [4]EUV lithography evaluation (1) [Examples 4-1~4-20, Comparative Examples 4-1~4-10] The chemical amplification resist compositions (R-1~R-20, CR-1~CR-10) shown in Tables 3 and 4 were spin-coated onto a Si substrate with a film thickness of 20 nm, which was formed on a silicon spin-coated hard mask SHB-A940 (silicon content of 43% by mass) manufactured by Shin-Etsu Chemical Industry Co., Ltd. The resist film with a film thickness of 50 nm was pre-baked at 100°C for 60 seconds using a hot plate. For the aforementioned resist film, an LS pattern with a size of 18 nm and a pitch of 36 nm was exposed on the wafer using an ASML EUV scanning exposure machine NXE3300 (NA 0.33, σ 0.9 / 0.6, dipole illumination) while varying the exposure amount and focus (exposure pitch: 1 mJ / cm2, focus pitch: 0.020 μm). After exposure, PEB was performed for 60 seconds at the temperatures shown in Tables 5 and 6. Subsequently, immersion development was performed for 30 seconds with a 2.38% (w / w) TMAH aqueous solution, followed by rinsing with a surfactant-containing elution material and spin drying to obtain a positive pattern. The obtained LS pattern was observed using a Hitachi Advanced Technology Co., Ltd. length measuring SEM (CG6300), and the sensitivity, EL, LWR, DOF, and collapse limit were evaluated using the following methods. The results are shown in Tables 5 and 6.

[0426] [Sensitivity Evaluation] The optimal exposure value Eop (mJ / cm2) for obtaining an LS pattern with a linewidth of 18nm and a pitch of 36nm is defined as the sensitivity. The smaller this value, the higher the sensitivity.

[0427] [EL Evaluation] The EL (unit: %) is calculated by the following formula based on the exposure within ±10% (16.2~19.8nm) of the 18nm pitch of the aforementioned LS pattern. A larger value indicates better performance. EL(%)=(|E1-E2| / Eop)×100 E1: Optimal exposure for an LS pattern with a linewidth of 16.2nm and a pitch of 36nm. E2: Optimal exposure for an LS pattern with a linewidth of 19.8nm and a pitch of 36nm. Eop: Optimal exposure for an LS pattern with a linewidth of 18nm and a pitch of 36nm.

[0428] [LWR Evaluation] For the LS pattern obtained by Eop irradiation, measure the dimensions at 10 points in the longitudinal direction of the line. Calculate 3 times the standard deviation (σ) (3σ) of the result as the LWR. The smaller this value, the smaller the roughness, and the more uniform the line width of the pattern.

[0429] [DOF Evaluation] As an evaluation of focal depth, the focal range formed by ±10% (16.2~19.8nm) of the 18nm dimension in the aforementioned LS pattern is calculated. The larger this value is, the wider the focal depth.

[0430] [Collapse Limit Evaluation of Line Patterns] The line dimensions of each exposure at the optimal focal point of the aforementioned LS pattern at 10 locations in the longitudinal direction were measured. The finest line dimension obtained without collapse is defined as the collapse limit dimension. The smaller this value, the better the collapse limit.

[0431] [Table 5] inhibitor Composition PEB temperature (°C) Optimal exposure (mJ / cm 2 ) EL (%) LWR (nm) DOF (nm) Collapse Limit (nm) Example 4-1 R-1 100 34 18 2.6 120 10.8 Example 4-2 R-2 95 33 18 2.5 120 10.6 Example 4-3 R-3 100 33 19 2.6 110 10.9 Example 4-4 R-4 105 34 18 2.7 100 11.5 Examples 4-5 R-5 100 34 18 2.8 120 11.3 Examples 4-6 R-6 95 33 17 2.6 110 11.5 Examples 4-7 R-7 100 35 19 2.7 120 11.6 Examples 4-8 R-8 100 34 18 2.7 120 11.5 Examples 4-9 R-9 105 33 17 2.6 110 11.2 Examples 4-10 R-10 100 35 18 2.6 100 11.1 Example 4-11 R-11 100 34 18 2.5 110 11.3 Example 4-12 R-12 100 35 16 2.7 110 11.0 Example 4-13 R-13 105 34 17 2.6 120 10.8 Example 4-14 R-14 100 35 19 2.7 110 11.2 Examples 4-15 R-15 100 34 17 2.5 120 11.4 Example 4-16 R-16 105 34 18 2.6 120 10.8 Example 4-17 R-17 95 34 18 2.7 110 10.9 Example 4-18 R-18 100 33 17 2.6 100 11.0 Example 4-19 R-19 100 34 19 2.7 120 11.3 Example 4-20 R-20 100 33 18 2.6 110 11.1

[0432] [Table 6] inhibitor Composition PEB temperature (°C) Optimal exposure (mJ / cm 2 ) EL (%) LWR (nm) DOF (nm) Collapse Limit (nm) Comparative Example 4-1 CR-1 105 41 13 3.6 90 13.4 Comparative Example 4-2 CR-2 100 39 13 3.1 90 12.8 Comparative Example 4-3 CR-3 100 37 11 4.2 70 12.7 Comparative Example 4-4 CR-4 100 39 13 3.1 90 12.2 Comparative Examples 4-5 CR-5 105 40 14 3.5 80 13.3 Comparative Examples 4-6 CR-6 95 39 12 3.1 100 12.5 Comparative Examples 4-7 CR-7 100 36 11 3.9 70 12.7 Comparative Examples 4-8 CR-8 100 38 14 3.4 90 12.7 Comparative Examples 4-9 CR-9 105 38 15 3.1 90 12.5 Comparative Example 4-10 CR-10 100 37 14 3.0 90 12.6

[0433] As shown in Tables 5 and 6, the chemical amplification inhibitor composition using a base polymer containing repeating units of the onium salt type monomer from the present invention exhibits good sensitivity and excellent EL, LWR, and DOF. Furthermore, it can be confirmed that the collapse limit value is small, and it is resistant to pattern collapse during the formation of fine patterns. Therefore, the chemical amplification inhibitor composition of the present invention is suitable as a material for EUV lithography.

[0434] [5]EUV lithography evaluation (2) [Examples 5-1~5-20, Comparative Examples 5-1~5-10] The chemical amplification resist compositions (R-1~R-20, CR-1~CR-10) shown in Tables 3 and 4 were spin-coated onto a Si substrate with a film thickness of 20 nm, which was formed on a silicon spin-coated hard mask SHB-A940 (silicon content of 43% by mass) manufactured by Shin-Etsu Chemical Industry Co., Ltd. The resist film with a film thickness of 50 nm was pre-baked at 105 °C for 60 seconds using a hot plate. Exposure was performed using an ASML EUV scanning exposure machine NXE3400 (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, mask for a 46nm pitch hole pattern on the wafer with +20% deviation). PEB was applied for 60 seconds using a hot plate at the temperatures described in Tables 7 and 8, followed by 30 seconds of development with a 2.38% (w / w) TMAH aqueous solution, forming a 23nm hole pattern. The exposure amount at the 23nm hole size was measured using a Hitachi Advanced Technology Co., Ltd. (CG6300) SEM and defined as the sensitivity. The dimensions of 50 holes were measured at this time, and the standard deviation (σ) was calculated as three times the value (3σ), defined as the size variation (CDU). The results are shown in Tables 7 and 8.

[0435] [Table 7] inhibitor composition PEB temperature (°C) Optimal exposure (mJ / cm 2 ) CDU (nm) Example 5-1 R-1 95 twenty two 2.3 Example 5-2 R-2 95 twenty one 2.2 Example 5-3 R-3 95 twenty two 2.3 Example 5-4 R-4 95 twenty two 2.3 Example 5-5 R-5 90 twenty two 2.2 Examples 5-6 R-6 90 twenty two 2.3 Examples 5-7 R-7 95 twenty one 2.4 Examples 5-8 R-8 95 twenty one 2.4 Examples 5-9 R-9 90 twenty two 2.3 Examples 5-10 R-10 95 twenty three 2.3 Examples 5-11 R-11 95 twenty four 2.4 Examples 5-12 R-12 95 twenty two 2.3 Examples 5-13 R-13 90 twenty one 2.2 Examples 5-14 R-14 95 twenty four 2.3 Examples 5-15 R-15 90 twenty three 2.4 Examples 5-16 R-16 90 twenty one 2.3 Examples 5-17 R-17 95 twenty two 2.1 Example 5-18 R-18 90 twenty three 2.2 Example 5-19 R-19 90 twenty four 2.4 Example 5-20 R-20 95 twenty two 2.2

[0436] [Table 8] inhibitor composition PEB temperature (°C) Optimal exposure (mJ / cm 2 ) CDU (nm) Comparative Example 5-1 CR-1 95 30 3.4 Comparative Example 5-2 CR-2 95 27 2.8 Comparative Example 5-3 CR-3 95 25 3.4 Comparative Example 5-4 CR-4 90 27 2.8 Comparative Example 5-5 CR-5 90 30 3.1 Comparative Examples 5-6 CR-6 95 27 2.9 Comparative Examples 5-7 CR-7 90 25 3.6 Comparative Examples 5-8 CR-8 90 25 2.7 Comparative Examples 5-9 CR-9 90 27 2.9 Comparative Examples 5-10 CR-10 95 26 2.7

[0437] The results shown in Tables 7 and 8 confirm that the chemical amplification inhibitor composition of the present invention has good sensitivity and excellent CDU.

[0438] [6] Dry Etching Resistance Evaluation [Examples 6-1~6-20, Comparative Examples 6-1~6-10] 2g of each of the polymers shown in Tables 1 and 2 (polymers P-1~P-20, comparative polymers CP-1~CP-10) were dissolved in 10g of cyclohexanone. After filtration through a 0.2μm filter, the polymer solution was spin-coated onto a Si substrate to form a film with a thickness of 300nm, and evaluated under the following conditions. Etching test with CHF3 / CF4 gas: The thickness difference of the polymer film before and after etching was determined using a TE-8500P dry etching apparatus manufactured by Tokyo Power Technology Co., Ltd. The etching conditions are as follows. Chamber pressure 40 Pa, RF power 1000 W, gap 9 mm, CHF3 gas flow rate 30 mL / min, CF4 gas flow rate 30 mL / min, Ar gas flow rate 100 mL / min, time 60 sec. In this evaluation, the smaller the film thickness difference, i.e., the smaller the reduction, the higher the etching resistance. The results of dry etching resistance are shown in Tables 9 and 10.

[0439] [Table 9] polymer CHF3 / CF4 gas etching rate (nm / min) Example 6-1 P-1 94 Example 6-2 P-2 96 Example 6-3 P-3 95 Example 6-4 P-4 94 Example 6-5 P-5 95 Example 6-6 P-6 94 Examples 6-7 P-7 95 Examples 6-8 P-8 96 Examples 6-9 P-9 94 Examples 6-10 P-10 97 Examples 6-11 P-11 96 Examples 6-12 P-12 95 Examples 6-13 P-13 94 Examples 6-14 P-14 96 Examples 6-15 P-15 98 Examples 6-16 P-16 96 Examples 6-17 P-17 97 Examples 6-18 P-18 95 Examples 6-19 P-19 94 Examples 6-20 P-20 95

[0440] [Table 10] polymer CHF3 / CF4 gas etching rate (nm / min) Comparative Example 6-1 CP-1 109 Comparative Example 6-2 CP-2 101 Comparative Example 6-3 CP-3 103 Comparative Example 6-4 CP-4 100 Comparative Example 6-5 CP-5 110 Comparative Example 6-6 CP-6 102 Comparative Examples 6-7 CP-7 101 Comparative Examples 6-8 CP-8 103 Comparative Examples 6-9 CP-9 104 Comparative Examples 6-10 CP-10 103

[0441] As shown in Tables 9 and 10, the results confirm that the polymer of the present invention has excellent dry etching resistance to CHF3 / CF4 gases.

Claims

1. A onium salt type monomer, comprising a cation represented by the following formula (a1-2) and an anion selected from the following group (a2) that does not contain an iodine atom, wherein m4 is an integer from 1 to 4; m5 is an integer from 0 to 4; m6 is an integer from 1 to 6; m7 is an integer from 1 to 6; m8 is an integer from 0 to 2; m9 is an integer from 0 to 2; m10 is an integer from 0 to 2; however, 1≦m6+m9≦4; 1≦m7+m10≦4; 1≦m4+m5+m8≦4; Each of RF1 to RF3 is independently a fluorine atom, a fluorinated saturated hydrocarbon group with 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxygen group with 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group with 1 to 6 carbon atoms; when m6 is 2 or more, each RF1 can be the same or different from each other; when m6 is 2 or more, each RF2 can be the same or different from each other; when m5 is 2 or more, each RF3 can be the same or different from each other. R1~R3 ​​can be halogen atoms other than iodine and fluorine atoms, nitro, cyano, or hydrocarbon groups with 1~20 carbon atoms containing heteroatoms, hydrocarbon oxygen groups with 1~20 carbon atoms containing heteroatoms, or hydrocarbon thio groups with 1~20 carbon atoms containing heteroatoms; when m8 is 2, the two R1s can be the same or different, and the two R1s can also bond to each other and form a ring with the carbon atoms they are bonded to; when m9 is 2, the two R2s can be the same or different, and the two R2s can also bond to each other and form a ring with the carbon atoms they are bonded to; when m10 is 2, the two R3s can be the same or different, and the two R3s can also bond to each other and form a ring with the carbon atoms they are bonded to; In group (a2), RA can be hydrogen atoms, fluorine atoms, methyl or trifluoromethyl atoms independently.

2. A monomeric photoacid generator, comprising an onium salt monomer as claimed in claim 1.

3. A polymer comprising repeating units from a monomeric photoacid generator as claimed in claim 2.

4. The polymer of claim 3 further contains repeating units represented by formula (b1) or (b2), wherein RA is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; X1 is a single bond, phenyl, naphthyl, *-C(=O)-O-X11-, or *-C(=O)-NH-X11-, which may also be substituted by a hydroxyl group, a nitro group, a cyano group, or an alkoxy or halogen atom containing fluorine atoms with 1 to 10 carbon atoms; X11 is a saturated alkyl group with 1 to 10 carbon atoms, phenyl or naphthyl, which may also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring; X2 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-; * represents an atomic bond between the main chain carbon atom; R11 can be a halogen atom, cyano, hydroxyl, nitro, or may contain a hydrocarbon group with 1 to 20 carbon atoms, a hydrocarbon oxygen group with 1 to 20 carbon atoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms, a hydrocarbon carbonyl oxygen group with 2 to 20 carbon atoms, or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms; AL1 and AL2 are each independently an acid-indeterminate group; a is an integer from 0 to 4.

5. The polymer of claim 3 further contains repeating units represented by the following formula (b3); where b1 is 0 or 1; b2 is an integer from 0 to 3 when b1 is 0, and an integer from 0 to 5 when b1 is 1; RA is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; X3 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-; * represents an atomic bond between the polymer and the carbon atom of the main chain; R12 and R13 are each independently hydrogen atoms, or may contain hydrocarbon groups with 1 to 20 carbon atoms of heteroatoms; furthermore, R12 and R13 may also be bonded to each other and form a ring together with the carbon atoms they are bonded to; R14 can be a halogen atom, hydroxyl group, cyano group, nitro group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon oxygen group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon thio group with 1 to 20 carbon atoms containing heteroatoms, or -N(R14A)(R14B); R14A and R14B are each independently a hydrogen atom or a hydrocarbon group with 1 to 6 carbon atoms; when b2 is 2 or more, multiple R14s can also bond to each other and form a ring together with the carbon atoms of the aromatic ring they are bonded to; X4 is a single bond, an aliphatic hydrocarbon group with 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining them; X5 and X6 are each independently an oxygen atom or a sulfur atom; however, X4 and X6 are bonded to adjacent carbon atoms of the aromatic ring.

6. The polymer of claim 3 further contains repeating units represented by the following formula (c1), where RA is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; Y1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-; * represents an atomic bond between the polymer and a carbon atom of the main chain; R21 is a halogen atom, a nitro group, a cyano group, a carboxyl group, or may contain a hydrocarbon group with 1 to 20 carbon atoms of heteroatoms, or a hydrocarbon oxygen group with 1 to 20 carbon atoms of heteroatoms, or a hydrocarbon carbonyl group with 2 to 20 carbon atoms of heteroatoms, or a hydrocarbon carbonyl group with 2 to 20 carbon atoms of heteroatoms; c is an integer from 1 to 4; d is an integer from 0 to 3; but 1 ≤ c + d ≤ 5.

7. The polymer of claim 3 further contains a repeating unit represented by the following formula (d1); wherein RA is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; Z1 is a single bond, a phenyl group, a naphthyl group, *-C(=O)-O-Z11- or *-C(=O)-NH-Z11-, which may also be substituted by a hydroxyl group, a nitro group, a cyano group, or an alkoxy group containing fluorine atoms with 1 to 10 carbon atoms or a halogen atom; * represents an atomic bond between the polymer and a carbon atom of the main chain; Z11 is a saturated alkyl group with 1 to 10 carbon atoms, a phenyl group, or a naphthyl group, which may also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring; R31 is a hydrogen atom, or a group with 1 to 20 carbon atoms containing at least one of the following: hydroxyl group (other than phenolic hydroxyl group), cyano group, carbonyl group, carboxyl group, ether bond, ester bond, sulfonate bond, carbonate bond, lactone ring, sulcinolone ring, and carboxylic anhydride (-C(=O)-OC(=O)-).

8. A chemical amplification inhibitor composition comprising (A) a base polymer containing the polymer of claim 3.

9. The chemical amplification inhibitor composition of claim 8 further contains (B) an organic solvent.

10. The chemical amplification inhibitor composition of claim 8 further contains (C) a quencher.

11. The chemical amplification inhibitor composition of claim 8 further contains (D) an acid generating agent.

12. The chemical amplification inhibitor composition of claim 8 further contains (E) surfactant.

13. The chemical amplification inhibitor composition of claim 8 further contains (F) a dissolution inhibitor.

14. A pattern forming method comprising the following steps: forming a resist film on a substrate using a chemical amplifying resist composition as claimed in claim 8; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developing solution.

15. The pattern forming method as described in claim 14, wherein, The high-energy rays are ArF excimer laser light with a wavelength of 193nm or KrF excimer laser light with a wavelength of 248nm, electron beams or extreme ultraviolet light with a wavelength of 3~15nm.