Onium salt type monomer, polymer, chemically amplified resist composition, and pattern forming method

Abstract

The invention relates to an onium salt type monomer, a polymer, a chemically amplified resist composition and a pattern forming method. The present invention provides a photolithographic composition which has excellent solvent solubility, high sensitivity, high contrast, excellent photolithographic performance such as exposure margin, edge roughness, size uniformity, and depth of focus in optical lithography using high-energy rays, and which can be used in optical lithography using high-energy rays. The present invention relates to an onium salt-type monomer used in a chemically amplified resist composition which can resist pattern collapse even when a fine pattern is formed, a polymer containing a repeating unit derived from the onium salt-type monomer, a chemically amplified resist composition containing the polymer, and a pattern forming method using the chemically amplified resist composition. An onium salt type monomer comprising a cation represented by formula (a1) and a sulfonic acid anion that contains a polymerizable group and does not contain an iodine atom. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to onium salt monomers, polymers, chemically amplified resist compositions, and a pattern forming method. Background Art

[0002] With the high integration and high speed of LSIs, the miniaturization of pattern rules has advanced rapidly. In particular, the expansion of the flash memory market and the increase in memory capacity have led the miniaturization. As the most advanced miniaturization technology, mass production of 65 nm node devices using ArF lithography has been carried out, and mass production preparation of 45 nm node devices using ArF immersion lithography for the next generation is underway. As the next generation of 32 nm node devices, immersion lithography using a liquid with a higher refractive index than water, a high refractive index lens, a high refractive index resist film, and an ultra-high NA lens, extreme ultraviolet (EUV) lithography with a wavelength of 13.5 nm, double exposure (double patterning lithography) of ArF lithography, etc. are candidates and are being studied.

[0003] As miniaturization progresses and approaches the diffraction limit of light, the contrast of light gradually decreases. Due to the decrease in the contrast of light, the resolution and focus tolerance of hole patterns and trench patterns in a positive resist film decrease.

[0004] As patterns are miniaturized, the edge roughness (LWR) of line patterns and the critical dimension uniformity (CDU) of hole patterns are regarded as problems. The effects of the concentration and aggregation of the base polymer and acid generator, and the effect of acid diffusion have been pointed out. Also, as the resist film becomes thinner, there is a tendency for the LWR to increase, and with the progress of miniaturization, the deterioration of the LWR due to thinning has become a serious problem.

[0005] The resist composition for EUV lithography must achieve high sensitivity, high resolution, and low LWR at the same time. If the acid diffusion distance is shortened, the LWR decreases but the sensitivity is low. For example, by reducing the post-exposure bake (PEB) temperature, the LWR decreases but the sensitivity is low. By increasing the addition amount of the quencher, the LWR also decreases, but the sensitivity decreases. It is necessary to break the trade-off relationship between sensitivity and LWR.

[0006] In order to suppress acid diffusion, a resist compound containing a repeating unit of an onium salt of a sulfonic acid having a polymerizable unsaturated bond has been proposed (Patent Document 1). Such a so-called polymer-bonded acid generator has the characteristic that acid diffusion is very short because polymersulfonic acid is generated by exposure. Also, the sensitivity can be increased by increasing the ratio of the acid generator. In the case of an additive acid generator, the sensitivity increases if the addition amount is increased, but in this case, the acid diffusion distance also increases. Since the acid diffuses unevenly, if the acid diffusion increases, the LWR and CDU deteriorate. In terms of the balance of sensitivity, LWR, and CDU, it can be said that the polymer-type acid generator has high performance.

[0007] The absorption of EUV with a wavelength of 13.5 nm by iodine atoms is very large. It has been confirmed that there is an effect of generating secondary electrons from iodine atoms in exposure, which has attracted attention in EUV lithography. Patent Document 2 describes a photoacid generator in which an iodine atom is introduced into an anion, and Patent Document 3 describes a photoacid generator containing a polymerizable group in which an iodine atom is introduced into an anion. Patent Document 4 describes a photoacid generator in which iodine atoms are introduced into both a cation and an anion. Thereby, although an improvement in lithography performance to a certain extent has been confirmed, since the solubility of iodine atoms in organic solvents is not high, there is a concern of precipitation in the solvent.

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

[0009] Patent Documents 6 to 11 describe photoacid generators and quenchers (acid diffusion control agents) in which iodine atoms and fluorine atoms are contained in a cation. Further, Patent Document 11 describes an onium salt monomer in which an iodine atom and a polymerizable group are introduced into a cation. Although an improvement in the performance as a photoresist material has been confirmed due to their development, from the viewpoint of considering acid diffusion control, it has not been satisfactory yet.

[0010] The generation of secondary electrons accompanying the absorption of EUV by iodine atoms contributes to the high sensitivity of the photoresist material, but the deterioration of lithography performance due to the diffusion of the generated secondary electrons has also become a problem. By appropriately controlling the diffusion of these secondary electrons, further performance improvement is expected. In order to meet the requirements for further miniaturization, the development of a photoresist material capable of overcoming the aforementioned problems is sought.

[0011] Prior Art Documents

[0012] Patent Documents

[0013] [Patent Document 1] Japanese Patent No. 4425776 Gazette

[0014] [Patent Document 2] Japanese Patent No. 6720926 Gazette

[0015] [Patent Document 3] Japanese Patent No. 6973274 Gazette

[0016] [Patent Document 4] Japanese Patent No. 7041204 Gazette

[0017] [Patent Document 5] Japanese Patent No. 7389562 Gazette

[0018] [Patent Document 6] Japanese Unexamined Patent Application Publication No. 2021 - 123579

[0019] [Patent Document 7] Japanese Patent Application Laid-Open No. 2021-123580

[0020] [Patent Document 8] Japanese Patent Application Laid-Open No. 2022-123839

[0021] [Patent Document 9] Japanese Patent Application Laid-Open No. 2023-88869

[0022] [Patent Document 10] Japanese Patent Application Laid-Open No. 2023-88870

[0023] [Patent Document 11] Japanese Patent Application Laid-Open No. 2022-28615 SUMMARY OF THE INVENTION

[0024] [Problems to be Solved by the Invention]

[0025] There is a need to develop a chemically amplified resist composition using an acid as a catalyst, which has higher sensitivity, can improve the LWR of line patterns and hole patterns, and has excellent CDU in terms of etching resistance after pattern formation.

[0026] In view of the above circumstances, an object of the present invention is to provide an onium salt type monomer, a polymer containing a repeating unit derived from the onium salt type monomer, a chemically amplified resist composition containing the polymer, and a pattern forming method using the chemically amplified resist composition, which are excellent in solvent solubility, high sensitivity, high contrast, and lithography performance such as exposure latitude (EL), LWR, CDU, and depth of focus (DOF) especially in optical lithography using high-energy rays such as KrF excimer laser, ArF excimer laser, electron beam (EB), and EUV, and are resistant to pattern collapse even when forming fine patterns and have excellent etching resistance.

[0027] [Means for Solving the Problems]

[0028] The inventors of the present application have made diligent studies to achieve the above object, and as a result, have found that a polymer containing a repeating unit of an onium salt type monomer composed of a sulfonic acid anion containing a polymerizable group and not containing an iodine atom and a triarylsulfonium cation containing an iodine atom and a fluorine atom has good solvent solubility. By using this polymer as a polymer-bonded photoacid generator, a chemically amplified resist composition with high sensitivity, high contrast, high resolution, improved lithography performance such as LWR and CDU, and excellent etching resistance after pattern formation can be obtained, and thus the present invention has been completed.

[0029] That is, the present invention provides the following onium salt type monomer, polymer, chemically amplified resist composition, and pattern forming method.

[0030] 1. An onium salt type monomer 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,

[0031] [Chemical Formula 1]

[0032]

[0033] In the formula, 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; 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.

[0034] R F 1 ~R F3 Each independently represents a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group having 1 to 6 carbon atoms. When m6 is 2 or more, each R F 1 may be the same or different from each other. When m7 is 2 or more, each R F2 may be the same or different from each other. When m5 is 2 or more, each R F3 may be the same or different from each other.

[0035] R 1 ~R 4 represents a halogen atom other than an iodine atom and a fluorine atom, a nitro group, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain heteroatoms, or a hydrocarbon thio group having 1 to 20 carbon atoms which may contain heteroatoms. When m8 is 2, the two R 1 may be the same or different from each other, and the two R 1 may also be bonded to each other and together with the carbon atom to which they are bonded form a ring. When m9 is 2, the two R 2 may be the same or different from each other, and the two R 2 may also be bonded to each other and together with the carbon atom to which they are bonded form a ring. When m10 is 2, the two R 3 may be the same or different from each other, and the two R 3 may also be bonded to each other and together with the carbon atom to which they are bonded form a ring. When m13 is 2, the two R 4May be the same or different from each other, two Rs 4 They may also be bonded to each other and together with the carbon atoms to which they are bonded form a ring.

[0036] Also, in the sulfonium cation, the aromatic rings directly bonded to S + may also be bonded to each other and together with S + form a ring.

[0037] L A and L B are each independently a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a sulfonamide bond, a carbonate bond or a carbamate bond.

[0038] X L is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain heteroatoms.

[0039] 2. The onium salt type monomer according to 1, wherein the structure of the anion is represented by any one of the following formulas (a2-1) to (a2-4),

[0040] [Chemical formula 2]

[0041]

[0042] In the formula, n1 and n2 are each independently an integer of 0 to 3. n3 is 0 or 1. n4 is an integer of 0 to 4. n5 is an integer of 0 to 4. However, when n3 = 0, 0 ≤ n4 + n5 ≤ 4, and when n3 = 1, 0 ≤ n4 + n5 ≤ 6.

[0043] R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0044] X A are each independently a single bond, a phenylene group, a naphthylene group which may have substituents or *-C(=O)-O-X A1 -. X A1 is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the aliphatic alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring.

[0045] X B are each independently a single bond, **-X B1 -C(=O)-O-, **-C(=O)-NH-X B1 - or **-O-X B 1 -. X B 1 is an alkylene group having 1 to 20 carbon atoms which may contain heteroatoms.

[0046] X C are each independently a single bond, ***-XC1 -C(=O)-O-, ***-C(=O)-NH-X C1 - or ***-O-X C1 -. X C1 is an alkylene group having 1 to 20 carbon atoms which may also contain heteroatoms.

[0047] X D is a single bond, methylene, ethylene, phenylene, fluorophenylene, phenyl substituted with trifluoromethyl, *-C(=O)-O-X D 1 -, *-C(=O)-N(H)-X D1 - or *-O-X D 1 -. X D 1 is an aliphatic alkylene group having 1 to 6 carbon atoms, phenylene, fluorophenylene or phenyl substituted with trifluoromethyl, and may also contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group.

[0048] * represents the atomic bond between the carbon atom of the main chain and ** represents the atomic bond with X A the atomic bond of. *** represents the atomic bond with X B the atomic bond of.

[0049] R 5 is a hydrocarbon group having 1 to 20 carbon atoms which may also contain heteroatoms. When n5 is 2, 3 or 4, multiple Rs 5 may also be bonded to each other and together with the carbon atoms to which they are bonded form a ring.

[0050] L C is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate bond, a carbonate bond or a carbamate bond.

[0051] Rf 1 and Rf 2 each independently is a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0052] Rf 3 and Rf 4 each independently is a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0053] Rf 5 and Rf 6 each independently is a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. However, not all Rfs 5 and Rf 6 simultaneously become hydrogen atoms.

[0054] Rf 7is a fluorine atom, a fluoroalkyl group having 1 to 6 carbon atoms, a fluoroalkoxy group having 1 to 6 carbon atoms, or a fluoroalkylthio group having 1 to 6 carbon atoms.

[0055] 3. The onium salt type monomer according to 1. or 2., wherein the cation is represented by the following formula (a1-1);

[0056] [Chemical formula 3]

[0057]

[0058] In the formula, m4 to m10, m12 to m14, R F1 ~R F3 、R 1 ~R 4 、L A 、L B and X L are as described above.

[0059] 4. The onium salt type monomer according to 3., wherein the cation is represented by the following formula (a1-2),

[0060] [Chemical formula 4]

[0061]

[0062] In the formula, m4 to m10, R F1 ~R F3 and R 1 ~R 3 are as described above.

[0063] 5. A monomeric photoacid generator composed of the onium salt type monomer according to any one of 1 to 4.

[0064] 6. A polymer containing repeating units derived from the monomeric photoacid generator according to 5.

[0065] 7. The polymer according to 6., further containing repeating units represented by the following formula (b1) or (b2),

[0066] [Chemical formula 5]

[0067]

[0068] In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0069] X 1 is a single bond, a phenylene group, a naphthylene group, *-C(=O)-O-X 11 - or *-C(=O)-NH-X 11-, the phenylene or naphthylene may also be substituted by a hydroxyl group, a nitro group, a cyano group, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. X 11 is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring.

[0070] X 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-.

[0071] * represents an atomic bond between the carbon atom of the main chain.

[0072] R 11 is a halogen atom, a cyano group, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom.

[0073] AL 1 and AL 2 are each independently an acid-labile group.

[0074] a is an integer of 0 to 4.

[0075] 8. The polymer according to 6. or 7. further contains a repeating unit represented by the following formula (b3);

[0076] [Chemical formula 6]

[0077]

[0078] In the formula, b1 is 0 or 1. When b1 is 0, b2 is an integer of 0 to 3, and when b1 is 1, b2 is an integer of 0 to 5.

[0079] R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0080] X 3 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * represents an atomic bond between the carbon atom of the main chain.

[0081] R 12 and R 13 are each independently a hydrogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. Further, R 12 and R 13 may also be bonded to each other and form a ring together with the carbon atoms to which they are bonded.

[0082] R 14is a halogen atom, a hydroxyl group, a cyano group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonthio group having 1 to 20 carbon atoms which may contain a hetero atom, or -N(R 14A )(R 14B ). R 14A and R 14B Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. 14 They may also be bonded to each other and to the carbon atoms of the aromatic ring to which they are bonded to form a ring.

[0083] X 4 It is a single bond, an aliphatic alkylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining these groups.

[0084] X 5 and X 6 Each independently represents an oxygen atom or a sulfur atom. 4 and X 6 Bonded to adjacent carbon atoms in an aromatic ring.

[0085] 9. The polymer according to any one of items 6 to 8, further comprising a repeating unit represented by the following formula (c1):

[0086] [Chemistry 7]

[0087]

[0088] Where R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0089] Y 1 It is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * represents an atomic bond with a carbon atom of the main chain.

[0090] R 21 It is a halogen atom, a nitro group, a cyano group, a carboxyl group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom.

[0091] c is an integer from 1 to 4. d is an integer from 0 to 3. However, 1≤c+d≤5.

[0092] 10. The polymer according to any one of items 6. to 9., further comprising a repeating unit represented by the following formula (d1);

[0093] [Chemistry 8]

[0094]

[0095] In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0096] Z 1 is a single bond, a phenylene group, a naphthylene group, *-C(=O)-O-Z 11 -, or *-C(=O)-NH-Z 11 -. The phenylene group or naphthylene group may also be substituted with a hydroxyl group, a nitro group, a cyano group, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. * represents an atomic bond between the carbon atom of the main chain and other atoms. Z 11 is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group. The saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring.

[0097] R 31 is a hydrogen atom, or a group having 1 to 20 carbon atoms containing at least one or more structures selected from hydroxyl groups other than phenolic hydroxyl groups, cyano groups, carbonyl groups, carboxyl groups, ether bonds, ester bonds, sulfonate ester bonds, carbonate ester bonds, lactone rings, sultone rings, and carboxylic anhydrides (-C(=O)-O-C(=O)-).

[0098] 11. A chemically amplified resist composition comprising (A) a base polymer containing a polymer as described in any one of 6. to 10.

[0099] 12. The chemically amplified resist composition according to 11., further comprising (B) an organic solvent.

[0100] 13. The chemically amplified resist composition according to 11. or 12., further comprising (C) a quencher.

[0101] 14. The chemically amplified resist composition according to any one of 11. to 13., further comprising (D) an acid generator.

[0102] 15. The chemically amplified resist composition according to any one of 11. to 14., further comprising (E) a surfactant.

[0103] 16. The chemically amplified resist composition according to any one of 11. to 15., further comprising (F) a dissolution inhibitor.

[0104] 17. A pattern forming method, comprising the following steps:

[0105] Forming a resist film on a substrate using the chemically amplified resist composition according to any one of 11. to 16.;

[0106] Exposing the aforementioned resist film to high-energy rays; and

[0107] Develop the aforementioned exposed resist film using a developer solution.

[0108] 18. The patterning method according to 17., wherein the aforementioned high-energy ray 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 light with a wavelength of 3 to 15 nm.

[0109] [Effects of the Invention]

[0110] A polymer containing a repeating unit of an onium salt monomer composed of a sulfonic acid anion containing a polymerizable group and not containing an iodine atom and a triarylsulfonium cation containing an iodine atom and a fluorine atom, and generating an acid upon exposure, has good solvent solubility due to the improved lipophilicity caused by the fluorine atom. The triarylsulfonium cation containing an iodine atom and a fluorine atom, especially in EUV lithography with a wavelength of 13.5 nm, has a very large absorption of EUV due to the iodine atom, so secondary electrons are generated from the iodine atom during exposure. Also, due to the electron-withdrawing effect caused by the fluorine atom, the energy level of the lowest unoccupied molecular orbital (LUMO) in the frontier orbital theory is lowered, making it easier to accept the generated secondary electrons, thus promoting the decomposition of the cation and effectively generating an acid. Furthermore, since there is an iodine atom near the sulfonium cation, the diffusion distance of the secondary electrons is shortened, and the secondary electrons effectively contribute to the decomposition of the cation. On the other hand, in the sulfonic acid anion containing a polymerizable group and not containing an iodine atom, the absence of an iodine atom in the anion can reduce the generation of secondary electrons and inhibit the deterioration of lithography performance accompanying the diffusion of secondary electrons. Also, due to the structure in which the generated acid is bonded to the polymer main chain, it has the characteristic of small acid diffusion. Thereby, it is possible to prevent the decrease in resolution due to acid diffusion blur, improve LWR and CDU, and the etching resistance after pattern formation is also excellent. Detailed Description of the Invention

[0111] [Onium Salt Monomer]

[0112] The onium salt monomer of the present invention contains a cation represented by the following formula (a1).

[0113] [Chemical Formula 9]

[0114]

[0115] In formula (a1), m1 is 0 or 1. When m1 is 0, it is a benzene ring, and when m1 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, a benzene ring with m1 = 0 is preferred. m2 is 0 or 1. When m2 is 0, it is a benzene ring, and when m2 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, a benzene ring with m2 = 0 is preferred. m3 is 0 or 1. When m3 is 0, it is a benzene ring, and when m3 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, a benzene ring with m3 = 0 is preferred.

[0116] In formula (a1), m4 is an integer from 0 to 4. The more iodine atoms in the cationic structure, the higher the absorption of EUV in particular, but the solvent solubility will be lacking and there is a concern of precipitation in the resist composition. Therefore, m4 is preferably 0, 1, 2 or 3, more preferably 0, 1 or 2.

[0117] In formula (a1), m5 is an integer from 0 to 4. From the perspective of raw material procurement, m5 is preferably 0, 1, 2 or 3, more preferably 0, 1 or 2. m6 is an integer from 0 to 6. From the perspective of raw material procurement, m6 is preferably 0, 1, 2 or 3, more preferably 0, 1 or 2. m7 is an integer from 0 to 6. From the perspective of raw material procurement, m7 is preferably 0, 1, 2 or 3, more preferably 0, 1 or 2.

[0118] In formula (a1), m8 is an integer from 0 to 2. From the perspective of raw material procurement, m8 is preferably 0 or 1. m9 is an integer from 0 to 2. From the perspective of raw material procurement, m9 is preferably 0 or 1. m10 is an integer from 0 to 2. From the perspective of raw material procurement, m10 is preferably 0 or 1.

[0119] In formula (a1), m11 is 0 or 1. When m11 is 0, it is a benzene ring, and when m11 is 1, it is a naphthalene ring. From the perspective of solvent solubility, the benzene ring with m11 being 0 is preferred.

[0120] In formula (a1), m12 is an integer from 0 to 4. The more iodine atoms in the cationic structure, the higher the absorption of EUV in particular, but the solvent solubility will be lacking and there is a concern of precipitation in the resist composition. Therefore, m12 is preferably 0, 1, 2 or 3, more preferably 0, 1 or 2.

[0121] In formula (a1), m13 is an integer from 0 to 2. From the perspective of raw material procurement, m13 is preferably 0 or 1. m14 is an integer from 0 to 2. From the perspective of synthesis, m14 is preferably 0 or 1.

[0122] 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, and when m2 is 1, 0 ≤ m7 + m10 ≤ 6. When m3 is 0, 1 ≤ m4 + m5 + m8 + m14 ≤ 4, and when m3 is 1, 1 ≤ m4 + m5 + m8 + m14 ≤ 6. When m11 is 0, 0 ≤ m12 + m13 ≤ 4, and when m11 is 1, 0 ≤ m12 + m13 ≤ 6. Also, m4 + m12 ≥ 1.

[0123] In formula (a1), R F1 ~R F3Each independently is a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxy 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 R F1 may be the same or different from each other. When m7 is 2 or more, each R F2 may be the same or different from each other. When m5 is 2 or more, each R F3 may be the same or different from each other.

[0124] In formula (a1), R 1 to R 4 are halogen atoms other than iodine atom and fluorine atom, nitro group, cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain heteroatoms, or a hydrocarbon thio group having 1 to 20 carbon atoms which may contain heteroatoms. The hydrocarbon moieties 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 thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl; cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 20 carbon atoms such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups having 3 to 20 carbon atoms such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms such as phenyl and naphthyl; aralkyl groups having 7 to 20 carbon atoms such as benzyl, 1-phenylethyl, and 2-phenylethyl; groups formed by combining these groups, etc. Further, a part or all of the hydrogen atoms of the hydrocarbon moieties of the aforementioned hydrocarbon group, hydrocarbon oxy group, and hydrocarbon thio group may be substituted with groups containing heteroatoms such as oxygen atom, sulfur atom, nitrogen atom, and halogen atom, and a part of -CH2- of the aforementioned hydrocarbon group may also be substituted with groups containing heteroatoms such as oxygen atom, sulfur atom, and nitrogen atom. As a result, it may contain hydroxyl group, cyano group, fluorine atom, chlorine atom, bromine atom, iodine atom, carbonyl group, ether bond, ester bond, sulfonate ester bond, carbonate ester bond, lactone ring, sultone ring, carboxylic anhydride (-C(=O)-O-C(=O)-), haloalkyl group, etc.

[0125] Further, when m8 is 2, the two R 1 may be the same or different from each other, and the two R 1 may also be bonded to each other and form a ring together with the carbon atom to which they are bonded. When m9 is 2, the two R 2 may be the same or different from each other, and the two R 2 may also be bonded to each other and form a ring together with the carbon atom to which they are bonded. When m10 is 2, the two R3 may be the same or different from each other, two Rs 3 may also be bonded to each other and together with the carbon atoms to which they are bonded form a ring. When m13 is 2, two Rs 4 may be the same or different from each other, two Rs 4 may also be bonded to each other and together with the carbon atoms to which they are bonded form a ring. Specific examples of the ring formed at this time include, for example, a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, an adamantane ring, etc. Further, a part or all of the hydrogen atoms in the aforementioned ring may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a part of -CH2- in the aforementioned ring may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and as a result, it may also contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0126] Further, in the sulfonium cation represented by the formula (a1), and S + the aromatic rings directly bonded to each other may also be bonded to each other and together with S + form a ring. Specific examples of the structure of the aforementioned ring at this time may include those represented by the following formula, etc.

[0127] [Chemical formula 10]

[0128]

[0129] In the formula, the dashed line is an atomic bond.

[0130] In the formula (a1), L A and L B are each independently a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a sulfonamide bond, a carbonate bond or a carbamate bond. Among these, L A is preferably a single bond, an ether bond, an ester bond or a sulfonate bond, more preferably an ester bond or a sulfonate bond. L B is preferably a single bond, an ether bond or an ester bond, more preferably a single bond.

[0131] In the formula (a1), X L is a single bond, or an alkylene group having 1 to 40 carbon atoms which may contain a heteroatom. Specific examples of the aforementioned alkylene group having 1 to 40 carbon atoms which may contain a heteroatom include, for example, the aforementioned alkylene group may be linear, branched or cyclic, and specific examples thereof include an alkanediyl group, a cycloaliphatic saturated alkylene group, an arylene group, etc. Specific examples of the aforementioned heteroatom include, for example, an oxygen atom, a nitrogen atom, a sulfur atom, etc.

[0132] X LSpecific examples of the divalent hydrocarbon group having 1 to 40 carbon atoms which may also contain heteroatoms are shown below, but are not limited thereto. In the following formulas, * each represents a bond with L A and L B respectively.

[0133] [Chemical formula 11]

[0134]

[0135] [Chemical formula 12]

[0136]

[0137] [Chemical formula 13]

[0138]

[0139] [Chemical formula 14]

[0140]

[0141] Among these, X L -0 to X L -22, X L -29 to X L -34, and X L -47 to X L -58 are preferred.

[0142] The sulfonium cation represented by formula (a1) is preferably the one represented by the following formula (a1-1).

[0143] [Chemical formula 15]

[0144]

[0145] In the formula, m4 to m10, m12 to m14, R F1 to R F3 , R 1 to R 4 , L A , L B and X L are as defined above.

[0146] The cation represented by formula (a1-1) is preferably the one represented by the following formula (a1-2).

[0147] [Chemical formula 16]

[0148]

[0149] In the formula, m4 to m10, R F1 to R F3 and R 1 to R 3As described above.

[0150] Specific examples of the sulfonium cation represented by formula (a1) are listed below, but are not limited to these. Also, in the following formulas, Me is methyl.

[0151] [Chemical formula 17]

[0152]

[0153] [Chemical formula 18]

[0154]

[0155] [Chemical formula 19]

[0156]

[0157] [Chemical formula 20]

[0158]

[0159] [Chemical formula 21]

[0160]

[0161] [Chemical formula 22]

[0162]

[0163] [Chemical formula 23]

[0164]

[0165] [Chemical formula 24]

[0166]

[0167] [Chemical formula 25]

[0168]

[0169] [Chemical formula 26]

[0170]

[0171] [Chemical formula 27]

[0172]

[0173] [Chemical formula 28]

[0174]

[0175] [Chemical formula 29]

[0176]

[0177] [Chemical formula 30]

[0178]

[0179] [Chemical formula 31]

[0180]

[0181] [Chemical formula 32]

[0182]

[0183] [Chemical formula 33]

[0184]

[0185] [Chemical formula 34]

[0186]

[0187] [Chemical formula 35]

[0188]

[0189] [Chemical formula 36]

[0190]

[0191] [Chemical formula 37]

[0192]

[0193] [Chemical formula 38]

[0194]

[0195] [Chemical formula 39]

[0196]

[0197] [Chemical formula 40]

[0198]

[0199] [Chemical formula 41]

[0200]

[0201] [Chemical formula 42]

[0202]

[0203] [Chemical formula 43]

[0204]

[0205] [Chemical formula 44]

[0206]

[0207] The onium salt type monomer of the present invention contains a sulfonic acid anion having a polymerizable group and not containing an iodine atom. It is preferable that the aforementioned sulfonic acid anion is any one of the following formulas (a2-1) to (a2-4).

[0208] [Chemical formula 45]

[0209]

[0210] In formulas (a2-1) to (a2-4), n1 and n2 are each independently an integer of 0 to 3, and it is preferable that 1 is used. n3 is 0 or 1. n4 is an integer of 0 to 4. n5 is an integer of 0 to 4. However, when n3 = 0, 0 ≤ n4 + n5 ≤ 4, and when n3 = 1, 0 ≤ n4 + n5 ≤ 6.

[0211] In formulas (a2-1) to (a2-4), R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. X A are each independently a single bond, a phenylene group which may have a substituent, a naphthylene group or *-C(=O)-O-X A1 -. X A1 is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the aliphatic alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. X B are each independently a single bond, **-X B 1 -C(=O)-O-, **-C(=O)-NH-X B 1 - or **-O-X B 1 -. X B1 is an alkylene group having 1 to 20 carbon atoms which may also contain a heteroatom. X C are each independently a single bond, ***-X C1 -C(=O)-O-, ***-C(=O)-NH-X C1 - or ***-O-X C1 -. X C1 is an alkylene group having 1 to 20 carbon atoms which may also contain a heteroatom. X D is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, *-C(=O)-O-X D1 -, *-C(=O)-N(H)-X D 1 - or *-O-X D1 -. X D1is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may also contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group. * represents an atomic bond between the carbon atom of the main chain. ** represents an atomic bond with X A is an atomic bond with. *** represents an atomic bond with X B is an atomic bond with.

[0212] X A1 and X D 1 The aliphatic alkylene group represented by can be linear, branched or cyclic. Specific examples thereof include alkanediyl groups such as methanediyl, ethane-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, hexane-1,6-diyl; cycloalkanediyl groups such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, cyclohexanediyl; groups obtained by combining them, etc.

[0213] X B 1 and X C1 The alkylene group represented by can be saturated or unsaturated, and can be linear, branched or cyclic. Specific examples thereof are listed below, but are not limited to these.

[0214] [Chemical formula 46]

[0215]

[0216] In the formula, the dashed line is an atomic bond.

[0217] In formulas (a2-1) to (a2-3), L C is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate bond, a carbonate bond or a carbamate bond. Among these, from the viewpoint of synthesis, an ether bond, an ester bond and a carbonyl group are preferable, and an ester bond and a carbonyl group are more preferable.

[0218] In formula (a2-1), Rf 1 and Rf 2 are each independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Among these, for Rf 1 and Rf 2 in order to increase the acid strength of the generated acid, it is preferable that both are fluorine atoms. Rf 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Among these, in order to improve the solubility in a solvent, Rf3 and Rf 4 It is preferred that at least one of them is a trifluoromethyl group.

[0219] In formula (a2-2), Rf 5 and Rf 6 are each independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. However, it is not the case that both Rf 5 and Rf 6 simultaneously become hydrogen atoms. Among these, in order to improve the solvent solubility, it is preferred that at least one of Rf 5 and Rf 6 is a trifluoromethyl group.

[0220] In formula (a2-3), Rf 7 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 alkylthio group having 1 to 6 carbon atoms. It is more preferable that Rf 7 is a fluorine atom, a trifluoromethyl group, a difluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group, a trifluoromethylthio group or a difluoromethylthio group, and it is even more preferable to be a fluorine atom, a trifluoromethyl group or a trifluoromethoxy group. When n4 is 2, 3 or 4, each Rf 7 may be the same or different from each other.

[0221] In formula (a2-3), R 5 is a hydrocarbon group having 1 to 20 carbon atoms which may also contain heteroatoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl; cycloaliphatic saturated hydrocarbon groups having 3 to 20 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, adamantyl; alkenyl groups having 2 to 20 carbon atoms such as vinyl, allyl, propenyl, butenyl, hexenyl; cycloaliphatic unsaturated hydrocarbon groups having 3 to 20 carbon atoms such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms such as phenyl, naphthyl; aralkyl groups having 7 to 20 carbon atoms such as benzyl, 1-phenylethyl, 2-phenylethyl; groups obtained by combining them, etc. Among these, an aryl group is preferred. Further, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may also be substituted with a group containing heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, and a part of -CH2- of the aforementioned hydrocarbon group may also be substituted with a group containing heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, and as a result, it may also contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. Further, when n5 is 2, 3 or 4, each R5 They may be the same as or different from each other.

[0222] Also, when n5 is 2, 3, or 4, multiple Rs 5 may also be bonded to each other and together with the carbon atoms of the aromatic ring to which they are bonded form a ring. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, an adamantane ring, etc. Also, a part or all of the hydrogen atoms in the aforementioned ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and a part of -CH2- in the aforementioned ring may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate ester bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0223] Specific examples of the anion represented by the formula (a2-1) are listed below, but are not limited to these. Also, in the following formula, R A is as described above.

[0224] [Chemical formula 47]

[0225]

[0226] [Chemical formula 48]

[0227]

[0228] [Chemical formula 49]

[0229]

[0230] [Chemical formula 50]

[0231]

[0232] [Chemical formula 51]

[0233]

[0234] [Chemical formula 52]

[0235]

[0236] Specific examples of the anion represented by the formula (a2-2) are listed below, but are not limited to these. Also, in the following formula, R A is as described above.

[0237] [Chemical formula 53]

[0238]

[0239] [Chemical formula 54]

[0240]

[0241] [Chemical Formula 55]

[0242]

[0243] [Chemical Formula 56]

[0244]

[0245] [Chemical Formula 57]

[0246]

[0247] [Chemical Formula 58]

[0248]

[0249] Specific examples of the anion represented by formula (a2-3) are listed below, but are not limited to these. Also, in the following formula, R A As described above.

[0250] [Chemical Formula 59]

[0251]

[0252] [Chemical Formula 60]

[0253]

[0254] [Chemical Formula 61]

[0255]

[0256] [Chemical Formula 62]

[0257]

[0258] [Chemical Formula 63]

[0259]

[0260] [Chemical Formula 64]

[0261]

[0262] [Chemical Formula 65]

[0263]

[0264] [Chemical Formula 66]

[0265]

[0266] [Chemical Formula 67]

[0267]

[0268] [Chemical formula 68]

[0269]

[0270] [Chemical formula 69]

[0271]

[0272] [Chemical formula 70]

[0273]

[0274] [Chemical formula 71]

[0275]

[0276] Specific examples of the anion represented by formula (a2-4) are listed below, but are not limited thereto. Also, in the following formula, R A As described above.

[0277] [Chemical formula 72]

[0278]

[0279] Specific examples of the onium salt type monomer of the present invention are any combination of the aforementioned anions and cations.

[0280] The onium salt type monomer of the present invention can be synthesized, for example, in the same manner as the sulfonium salt having a polymerizable anion described in Japanese Patent No. 5201363, but is not limited thereto.

[0281] [Polymer]

[0282] The polymer of the present invention contains a repeating unit (hereinafter also referred to as repeating unit A) of an onium salt type monomer composed of a cation represented by formula (a1) and a sulfonic acid anion containing a polymerizable group and not containing an iodine atom.

[0283] The polymer of the present invention is a polymer-bonded photoacid generator that acts as a base polymer in a chemically amplified resist composition and also acts as a photoacid generator. A triarylsulfonium cation containing an iodine atom and a fluorine atom, especially in EUV lithography with a wavelength of 13.5 nm, has a very large absorption of EUV caused by the iodine atom, so secondary electrons are generated from the iodine atom during exposure. Also, due to the electron-withdrawing effect caused by the fluorine atom, the energy level of the lowest unoccupied molecular orbital (LUMO) in the frontier orbital theory decreases, making it easier to accept the generated secondary electrons. Therefore, the decomposition of the cation in the same structure located physically nearby is promoted, and acid is effectively generated. On the other hand, the sulfonic acid anion substituted with a polymerizable group does not necessarily have to contain an iodine atom. When the anion contains an iodine atom, the physical distance for the secondary electrons generated from the iodine atom to move to the sulfonium cation is long, resulting in the diffusion of secondary electrons, and thus the lithography performance deteriorates. Also, iodine atoms are elements with relatively poor water solubility, so the iodine atoms in the anion decrease the solubility of the polymer after the acid detachment reaction. Especially in the case of a positive resist developed with alkali, the solubility of the polymer after the acid detachment reaction in the alkali developer decreases, so the possibility of causing development defects is high. Due to the above, the polymer of the present invention improves various lithography performances and has a low risk of development defects by appropriately controlling the diffusion of secondary electrons, and is especially suitable as a material for a chemically amplified positive resist composition.

[0284] The aforementioned polymer may further contain a repeating unit represented by the following formula (b1) (hereinafter also referred to as repeating unit b1) or a repeating unit represented by the following formula (b2) (hereinafter also referred to as repeating unit b2).

[0285] [Chemical Formula 73]

[0286]

[0287] In formulas (b1) and (b2), R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0288] In formula (b1), X 1 is a single bond, a phenylene group, a naphthylene group, *-C(=O)-O-X 11 -, or *-C(=O)-NH-X 11 -, and the phenylene group or naphthylene group may also be substituted with a hydroxyl group, a nitro group, a cyano group, an alkoxy group having 1 to 10 carbon atoms that may contain a fluorine atom, or a halogen atom. X 11 is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group, and the saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. * represents the atomic bond between the carbon atom of the main chain.

[0289] In formula (b2), X 2is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents an atomic bond between the carbon atom of the main chain and other atoms. R 11 is a halogen atom, a cyano group, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon carbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon carbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom. a is an integer from 0 to 4, preferably 0 or 1.

[0290] In formulas (b1) and (b2), AL 1 and AL 2 are each independently an acid-labile group. Specific examples of the acid-labile group include, but are not limited to, those described in JP-A-2013-80033 and JP-A-2013-83821.

[0291] Generally, specific examples of the acid-labile group are represented by the following formulas (AL-1) to (AL-3).

[0292] [Chemical formula 74]

[0293]

[0294] In the formula, * is an atomic bond.

[0295] In formulas (AL-1) and (AL-2), R L1 and R L2 are each independently a hydrocarbon group having 1 to 40 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a fluorine atom, or an iodine atom. The hydrocarbon group may be linear, branched, or cyclic. The hydrocarbon group preferably has 1 to 20 carbon atoms.

[0296] In formula (AL-1), b is an integer from 0 to 10, preferably an integer from 1 to 5.

[0297] In formula (AL-2), R L3 and R L4 are each independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a fluorine atom, or an iodine atom. The hydrocarbon group may be linear, branched, or cyclic. Also, any two of R L2 , R L3 and R L4 may be bonded to each other and, together with the carbon atom or carbon atoms and oxygen atom to which they are bonded, form a ring having 3 to 20 carbon atoms. The ring preferably has 4 to 16 carbon atoms, and an alicyclic ring is more preferable.

[0298] In formula (AL-3), RL5 , R L6 and R L7 are each independently a hydrocarbon group having 1 to 20 carbon atoms, and may also contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, a fluorine atom, and an iodine atom. The aforementioned hydrocarbon group may be linear, branched, or cyclic. Also, any two of R L5 , R L6 and R L7 may also be bonded to each other and, together with the carbon atoms to which they are bonded, form a ring having 3 to 20 carbon atoms. The aforementioned ring is preferably a ring having 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0299] Specific examples of the repeating unit b1 are listed below, but are not limited to these. Also, in the following formula, R A and AL 1 are as described above.

[0300] [Chemical formula 75]

[0301]

[0302] [Chemical formula 76]

[0303]

[0304] [Chemical formula 77]

[0305]

[0306] [Chemical formula 78]

[0307]

[0308] [Chemical formula 79]

[0309]

[0310] [Chemical formula 80]

[0311]

[0312] [Chemical formula 81]

[0313]

[0314] Specific examples of the repeating unit b2 are listed below, but are not limited to these. Also, in the following formula, R A and AL 2 are as described above.

[0315] [Chemical formula 82]

[0316]

[0317] [Chemical formula 83]

[0318]

[0319] [Chemical Formula 84]

[0320]

[0321] The aforementioned polymer may further contain a repeating unit represented by the following formula (b3) (hereinafter also referred to as repeating unit b3).

[0322] [Chemical Formula 85]

[0323]

[0324] In formula (b3), b1 is 0 or 1. When b1 is 0, it is a benzene ring, and when b1 is 1, it is a naphthalene ring. However, from the perspective of solvent solubility, the benzene ring with b1 = 0 is preferred. When b1 is 0, b2 is an integer from 0 to 3, and when b1 is 1, b2 is an integer from 0 to 5. From the perspective of raw material procurement, b2 is preferably 0, 1, 2, or 3, more preferably 0, 1, or 2.

[0325] In formula (b3), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, a hydrogen atom and a methyl group are preferred, and a hydrogen atom is more ideal.

[0326] In formula (b3), X 3 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents the atomic bond between the carbon atom of the main chain. Among these, a single bond and *-C(=O)-O- are preferred, and a single bond is more ideal.

[0327] In formula (b3), R 12 and R 13Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl; cycloaliphatic saturated hydrocarbon groups having 3 to 20 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, adamantyl; alkenyl groups having 2 to 20 carbon atoms such as vinyl, allyl, propenyl, butenyl, hexenyl; cycloaliphatic unsaturated hydrocarbon groups having 3 to 20 carbon atoms such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms such as phenyl, naphthyl; aralkyl groups having 7 to 20 carbon atoms such as benzyl, 1-phenylethyl, 2-phenylethyl; groups obtained by combining them, etc. Further, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, and a part of -CH2- of the aforementioned hydrocarbon group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, and as a result, it may also contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0328] Further, R 12 and R 13 may also be bonded to each other and together with the carbon atom to which they are bonded, form a ring. Specific examples of the ring formed at this time include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, an adamantane ring, etc. Further, a part or all of the hydrogen atoms in the aforementioned ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, and a part of -CH2- in the aforementioned ring may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, and as a result, it may also contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0329] In formula (b3), R 14 represents a halogen atom, a hydroxyl group, a cyano group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may also contain a heteroatom, a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may also contain a heteroatom, a hydrocarbon thio group having 1 to 20 carbon atoms which may also contain a heteroatom or -N(R 14A )(R 14B ). R 14A and R 14BEach independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. The halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, more preferably a fluorine atom or an iodine atom. The hydrocarbon group part of the aforementioned hydrocarbon group, hydrocarbon oxy group, hydrocarbon oxycarbonyl group and hydrocarbon thio group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof are the same as the hydrocarbon group examples represented by R 12 and R 13 . Also, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of -CH2- of the aforementioned hydrocarbon group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. When b2 is 2 or more, each R 14 may be the same or different from each other.

[0330] Also, when b2 is 2 or more, multiple R 14 may also be bonded to each other and form a ring together with the carbon atoms of the aromatic ring to which they are bonded. Specific examples of the ring formed at this time are a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, an adamantane ring, etc. Also, part or all of the hydrogen atoms in the aforementioned ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of -CH2- in the aforementioned ring may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0331] In formula (b3), X 4 is a single bond, an aliphatic alkylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining them. Among these, from the viewpoint of raw material procurement, a single bond, a carbonyl group or a sulfonyl group is preferred, and from the viewpoint of the polar group generated after the reaction, a single bond or a carbonyl group is more preferred.

[0332] In formula (b3), X 5 and X 6 each independently represents an oxygen atom or a sulfur atom. However, X 4 and X 6 are bonded to adjacent carbon atoms of the aromatic ring. X 5 and X 6 may be the same or different from each other, and from the viewpoint of reactivity, it is preferred that both X 5 and X 6 are oxygen atoms.

[0333] Specific examples of the repeating unit b3 are listed below, but are not limited to these. Also, in the following formula, R A As described above, Me is a methyl group. Also, the bonding positions of various substituents on the aromatic ring can be interchanged with each other.

[0334] [Chemical Formula 86]

[0335]

[0336] [Chemical Formula 87]

[0337]

[0338] [Chemical Formula 88]

[0339]

[0340] [Chemical Formula 89]

[0341]

[0342] [Chemical Formula 90]

[0343]

[0344] [Chemical Formula 91]

[0345]

[0346] [Chemical Formula 92]

[0347]

[0348] [Chemical Formula 93]

[0349]

[0350] [Chemical Formula 94]

[0351]

[0352] [Chemical Formula 95]

[0353]

[0354] [Chemical Formula 96]

[0355]

[0356] [Chemical Formula 97]

[0357]

[0358] [Chemical Formula 98]

[0359]

[0360] [Chemical Formula 99]

[0361]

[0362] [Chemical Formula 100]

[0363]

[0364] [Chemical Formula 101]

[0365]

[0366] [Chemical Formula 102]

[0367]

[0368] [Chemical Formula 103]

[0369]

[0370] [Chemical Formula 104]

[0371]

[0372] [Chemical Formula 105]

[0373]

[0374] [Chemical Formula 106]

[0375]

[0376] [Chemical Formula 107]

[0377]

[0378] [Chemical Formula 108]

[0379]

[0380] [Chemical Formula 109]

[0381]

[0382] [Chemical Formula 110]

[0383]

[0384] [Chemical Formula 111]

[0385]

[0386] [Chemical Formula 112]

[0387]

[0388] [Chemical Formula 113]

[0389]

[0390] [Chemical Formula 114]

[0391]

[0392] [Chemical Formula 115]

[0393]

[0394] [Chemical Formula 116]

[0395]

[0396] [Chemical Formula 117]

[0397]

[0398] [Chemical Formula 118]

[0399]

[0400] [Chemical Formula 119]

[0401]

[0402] [Chemical Formula 120]

[0403]

[0404] [Chemical Formula 121]

[0405]

[0406] [Chemical Formula 122]

[0407]

[0408] [Chemical Formula 123]

[0409]

[0410] [Chemical Formula 124] [[ID=A]]

[0411]

[0412] [Chemical Formula 125]

[0413]

[0414] [Chemical Formula 126]

[0415]

[0416] [Chemical formula 127]

[0417]

[0418] [Chemical formula 128]

[0419]

[0420] [Chemical formula 129]

[0421]

[0422] [Chemical formula 130]

[0423]

[0424] [Chemical formula 131]

[0425]

[0426] [Chemical formula 132]

[0427]

[0428] [Chemical formula 133]

[0429]

[0430] [Chemical formula 134]

[0431]

[0432] [Chemical formula 135]

[0433]

[0434] Preferably, the aforementioned polymer further contains a repeating unit represented by the following formula (c1) (hereinafter also referred to as repeating unit c).

[0435] [Chemical formula 136]

[0436]

[0437] In formula (c1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Y 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * represents an atomic bond between the carbon atom of the main chain. R 21is a halogen atom, nitro group, cyano group, carboxyl group, a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain heteroatoms, a hydrocarbon carbonyl group having 2 to 20 carbon atoms which may contain heteroatoms, a hydrocarbon carbonyloxy group having 2 to 20 carbon atoms which may contain heteroatoms or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain heteroatoms. c is an integer of 1 to 4. d is an integer of 0 to 3. However, 1 ≤ c + d ≤ 5.

[0438] Specific examples of the repeating unit c are listed below, but are not limited thereto. Further, in the following formula, R A As described above.

[0439] [Chemical formula 137]

[0440]

[0441] [Chemical formula 138]

[0442]

[0443] [Chemical formula 139]

[0444]

[0445] [Chemical formula 140]

[0446]

[0447] [Chemical formula 141]

[0448]

[0449] It is preferable that the aforementioned polymer further contains a repeating unit represented by the following formula (d1) (hereinafter also referred to as repeating unit d).

[0450] [Chemical formula 142]

[0451]

[0452] In the formula (d1), R A is a hydrogen atom, fluorine atom, methyl group or trifluoromethyl group. Z 1 is a single bond, phenylene group, naphthylene group, *-C(=O)-O-Z 11 - or *-C(=O)-NH-Z 11 -, and the phenylene group or naphthylene group may also be substituted with a hydroxyl group, nitro group, cyano group, an alkoxy group having 1 to 10 carbon atoms which may contain fluorine atoms or a halogen atom. * represents an atomic bond between the carbon atom of the main chain. Z 11 is a saturated alkylene group having 1 to 10 carbon atoms, phenylene group or naphthylene group, and the saturated alkylene group may also contain a hydroxyl group, ether bond, ester bond or lactone ring. R 31is a hydrogen atom, a group having 1 to 20 carbon atoms and containing at least one or more structures selected from hydroxyl groups other than phenolic hydroxyl groups, cyano groups, carbonyl groups, carboxyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, and carboxylic anhydrides (-C(=O)-O-C(=O)-).

[0453] Specific examples of the repeating unit d are listed below, but are not limited to these. Also, in the following formula, R A As described above.

[0454] [Chemical formula 143]

[0455]

[0456] [Chemical formula 144]

[0457]

[0458] [Chemical formula 145]

[0459]

[0460] [Chemical formula 146]

[0461]

[0462] [Chemical formula 147]

[0463]

[0464] [Chemical formula 148]

[0465]

[0466] [Chemical formula 149]

[0467]

[0468] [Chemical formula 150]

[0469]

[0470] [Chemical formula 151]

[0471]

[0472] [Chemical formula 152]

[0473]

[0474] [Chemical formula 153]

[0475]

[0476] [Chemical formula 154]

[0477]

[0478] [Chemical formula 155]

[0479]

[0480] [Chemical formula 156]

[0481]

[0482] [Chemical formula 157]

[0483]

[0484] [Chemical formula 158]

[0485]

[0486] Regarding the repeating unit d, in ArF lithography, those having a lactone ring as a polar group are particularly preferable, and in KrF lithography, EB lithography, and EUV lithography, those having a phenol moiety are better.

[0487] The aforementioned polymer may further contain a repeating unit having a structure in which a hydroxyl group is protected by an acid-labile group (hereinafter also referred to as repeating unit e). The repeating unit e may be any one as long as it has a structure in which one or more hydroxyl groups are protected and the protecting group is decomposed by the action of an acid to generate a hydroxyl group, and is not particularly limited. Those represented by the following formula (e1) are preferable.

[0488] [Chemical formula 159]

[0489]

[0490] In formula (e1), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 41 is an (e + 1)-valent hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom. R 42 is an acid-labile group. e is an integer of 1 to 4.

[0491] In formula (e1), the acid-labile group represented by R 42 may be any one as long as it is deprotected by the action of an acid to generate a hydroxyl group. The structure of R 42 is not particularly limited, and an acetal structure, a ketal structure, an alkoxycarbonyl group, an alkoxymethyl group represented by the following formula (e2), etc. are preferable, and an alkoxymethyl group represented by the following formula (e2) is particularly preferable.

[0492] [Chemical formula 160]

[0493]

[0494] In the formula, * represents an atomic bond. R 43 is a hydrocarbon group having 1 to 15 carbon atoms.

[0495] R 42 The acid-labile group represented and the specific examples of the alkoxymethyl group represented by the formula (e2) and the repeating unit e are the same as the illustrative examples of the repeating unit d described in Japanese Patent Application Laid-Open No. 2020-111564.

[0496] The aforementioned polymer may further contain a repeating unit f derived from indene, benzofuran, benzothiophene, vinylnaphthalene, chromone, coumarin, norbornadiene or a derivative thereof. Specific examples of the monomer that gives the repeating unit f are listed below, but are not limited thereto.

[0497] [Chemical 161]

[0498]

[0499] The aforementioned polymer may further contain a repeating unit g derived from styrene, indene, vinylpyridine or vinylcarbazole.

[0500] In the polymer of the present invention, the content ratios of the repeating units a, b1, b2, b3, c, d, e, f and g are 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, more 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. However, a + b1 + b2 + b3 + c + d + e + f + g ≤ 1.0.

[0501] The weight average molecular weight (Mw) of the aforementioned polymer is preferably 1000 to 500000, more preferably 3000 to 100000. If Mw is within this range, sufficient etching resistance can be obtained, and there is no fear of a decrease in resolution due to the inability to ensure the difference in dissolution rate before and after exposure. Also, in the present invention, Mw is a polystyrene conversion measurement value obtained by gel permeation chromatography (GPC) using tetrahydrofuran (THF) or N,N-dimethylformamide (DMF) as a solvent.

[0502] Also, as the pattern rule becomes finer, the influence of the molecular weight distribution (Mw / Mn) of the aforementioned polymer becomes more likely to increase. Therefore, in order to obtain a resist composition suitable for use with a fine pattern size, a narrow dispersion with Mw / Mn of 1.0 to 2.0 is preferred. If it is within the aforementioned range, there are few low molecular weight and high molecular weight polymers, and after exposure, there is no fear of foreign matter appearing on the pattern or the shape of the pattern deteriorating.

[0503] The synthesis method of the aforementioned polymer, for example, a method in which monomers that give the aforementioned repeating units are added with a radical polymerization initiator and heated in an organic solvent to polymerize them.

[0504] Specific examples of the organic solvent used in the polymerization include toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), γ-butyrolactone (GBL), etc. Specific examples of the aforementioned polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, lauroyl peroxide, etc. The addition amount of these initiators is preferably 0.01 to 25 mol% relative to the total of the monomers to be polymerized. The reaction temperature is preferably 50 to 150 °C, more preferably 60 to 100 °C. The reaction time is preferably 2 to 24 hours, and from the viewpoint of production efficiency, 2 to 12 hours is more preferable.

[0505] The aforementioned polymerization initiator can be added to the aforementioned monomer solution and supplied to the reaction kettle, or a starter solution can be prepared separately from the aforementioned monomer solution, and they can be supplied to the reaction kettle independently. During the standby time, the polymerization reaction may proceed due to the radicals generated from the initiator and ultra-high molecular substances may be generated. Therefore, from the viewpoint of quality control, it is preferable to prepare and drop the monomer solution and the initiator solution independently. Monomers into which acid-labile groups have been introduced can be used directly, or they can be protected or partially protected after polymerization. Also, in order to adjust the molecular weight, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol can be used in combination. In this case, the addition amount of these chain transfer agents is preferably 0.01 to 20 mol% relative to the total of the monomers to be polymerized.

[0506] When it is a monomer containing a hydroxyl group, during the polymerization, the hydroxyl group can be previously substituted with an acetal group such as ethoxyethoxy that is easily deprotected by an acid, and after polymerization, it can be deprotected with a weak acid and water. It can also be previously substituted with an acetyl group, a formyl group, a trimethylacetyl group, etc., and after polymerization, it can be subjected to base hydrolysis.

[0507] When hydroxy styrene or hydroxy vinyl naphthalene is copolymerized, hydroxy styrene or hydroxy vinyl naphthalene and other monomers can be added with a radical polymerization initiator in an organic solvent and heated for polymerization, or acetoxy styrene or acetoxy vinyl naphthalene can be used, and after polymerization, the acetoxy group can be deprotected by base hydrolysis to become polyhydroxy styrene or hydroxy polyvinyl naphthalene.

[0508] Specific examples of the base used in base hydrolysis include, for example, ammonia water, triethylamine, etc. Further, the reaction temperature is preferably -20 to 100 °C, more preferably 0 to 60 °C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0509] Also, the amounts of the respective monomers in the monomer solution can be appropriately set, for example, to achieve the desired content ratio of the repeating units described above.

[0510] For the polymer obtained by the above production method, the reaction solution obtained by the polymerization reaction can be used as the final product, or the powder obtained through purification steps such as the reprecipitation method in which the polymerization solution is added to a poor solvent to obtain a powder can be used as the final product. From the viewpoints of operation efficiency and quality stabilization, it is preferable to treat the polymer solution obtained by dissolving the powder obtained through the purification steps in a solvent as the final product.

[0511] Specific examples of the solvent used at this time include, for example, ketones such as cyclohexanone and methyl-2-n-amyl ketone described in paragraphs

[0144] to

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

[0512] In the above polymer solution, the concentration of the polymer is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass.

[0513] It is preferable to filter the above reaction solution and polymer solution through a filter. By performing filter filtration, foreign matters and gels that may cause defects can be removed, which is effective for quality stabilization.

[0514] Examples of the material of the filter used for the filtration described above include materials such as fluorocarbon-based, cellulose-based, nylon-based, polyester-based, and hydrocarbon-based materials. However, in the filtration step of the chemically amplified resist composition, filters made of fluorocarbon-based materials such as so-called Teflon (registered trademark), hydrocarbon-based materials such as polyethylene and polypropylene, or nylon are preferred. The pore size of the filter can be appropriately selected according to the target cleanliness, but it is preferably 100 nm or less, more preferably 20 nm or less. Also, these filters can be used alone, or multiple filters can be used in combination. The filtration method can be to pass the solution only once, but it is better to circulate the solution and perform multiple filtrations. The filtration step can be carried out in any order and number of times in the polymer manufacturing step, but it is preferred to filter the reaction solution, polymer solution, or both after the polymerization reaction.

[0515] [Chemically amplified resist composition]

[0516] [(A) Base polymer]

[0517] In the chemically amplified resist composition of the present invention, a base polymer containing the aforementioned polymer is contained as component (A).

[0518] The aforementioned polymer can be used alone, or two or more kinds having different composition ratios, Mw, and / or Mw / Mn can be used in combination. Also, the (A) base polymer can contain, in addition to the aforementioned polymer, a hydride of a ring-opening metathesis polymer, and for this, those described in Japanese Patent Application Laid-Open No. 2003-66612 can be used.

[0519] [(B) Quencher]

[0520] The chemically amplified resist composition of the present invention may also contain a quencher as component (B). Also, in the present invention, a quencher is a material that forms a desired pattern by capturing the acid generated by the photoacid generator in the chemically amplified resist composition and preventing the acid from diffusing to the unexposed portion.

[0521] Specific examples of the (B) quencher are onium salts represented by the following formula (1) or (2).

[0522] [Chemical formula 162]

[0523]

[0524] In formula (1), R q1 is a hydrogen atom, or a hydrocarbon group having 1 to 40 carbon atoms that may contain a heteroatom, provided that the hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is not substituted by a fluorine atom or a fluoroalkyl group. In formula (2), R q2 is a hydrogen atom, or a hydrocarbon group having 1 to 40 carbon atoms that may contain a heteroatom.

[0525] R q1The hydrocarbon groups represented by carbon numbers 1 to 40, specifically, for example, alkyl groups having 1 to 40 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl; cycloaliphatic saturated hydrocarbon groups having 3 to 40 carbon atoms such as cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, tricyclo[5.2.1.0 2,6 decyl, adamantyl; aryl groups having 6 to 40 carbon atoms such as phenyl, naphthyl, anthryl. Further, some or all of the hydrogen atoms of the aforementioned hydrocarbon groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and a part of -CH2- of the aforementioned hydrocarbon groups may also be substituted with groups 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 ester bonds, carbonate ester bonds, lactone rings, sultone rings, carboxylic anhydrides (-C(=O)-O-C(=O)-), haloalkyl groups, etc.

[0526] R q2 The hydrocarbon group represented, specifically, in addition to the substituents exemplified for the specific examples of R q1 , fluorinated saturated hydrocarbon groups such as trifluoromethyl and trifluoroethyl, and fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl can also be cited.

[0527] Specific examples of the anion of the onium salt represented by formula (1) are listed below, but are not limited to these.

[0528] [Chemical formula 163]

[0529]

[0530] [Chemical formula 164]

[0531]

[0532] [Chemical formula 165]

[0533]

[0534] Specific examples of the anion of the onium salt represented by formula (2) are listed below, but are not limited to these.

[0535] [Chemical formula 166]

[0536]

[0537] [Chemical formula 167]

[0538]

[0539] [Chemical formula 168]

[0540]

[0541] In Formulas (1) and (2), Mq + is an onium cation. It is preferable that the onium cation is a sulfonium cation represented by the following formula (cation-1), an iodonium cation represented by the following formula (cation-2), or an ammonium cation represented by the following formula (cation-3).

[0542] [Chemical 169]

[0543]

[0544] In Formulas (cation-1) and (cation-2), R ct1 ~R ct5 are each independently a halogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom.

[0545] R ct1 ~R ct5 Specific examples of the halogen atom represented by R include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.

[0546] R ct1 ~R ct5 The hydrocarbon group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms such as a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group; cycloaliphatic saturated hydrocarbon groups having 3 to 30 carbon atoms such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a 4-methylcyclohexyl group, a cyclohexylmethyl group, a norbornyl group, an adamantyl group; alkenyl groups having 2 to 30 carbon atoms such as a vinyl group, an allyl group, a propenyl group, a butenyl group, a hexenyl group; cycloaliphatic unsaturated hydrocarbon groups having 3 to 30 carbon atoms such as a cyclohexenyl group; aryl groups having 6 to 30 carbon atoms such as a phenyl group, a naphthyl group, a thienyl group; aralkyl groups having 7 to 30 carbon atoms such as a benzyl group, a 1-phenylethyl group, a 2-phenylethyl group; groups obtained by combining them, etc., and aryl groups are preferable. Further, a part or all of the hydrogen atoms of the hydrocarbon group may be replaced by a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a part of -CH2- of the hydrocarbon group may also be replaced by a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0547] Further, R ct1 and R ct2They may be bonded to each other and form a ring together with the sulfur atom to which they are bonded. Specific examples of the ring structure include those represented by the following formula.

[0548] [Chemistry 170]

[0549]

[0550] Where, the chain line is and R ct3 atomic bonds.

[0551] Specific examples of the sulfonium cation represented by formula (cation-1) include the following, but are not limited to these.

[0552] [Chemistry 171]

[0553]

[0554] [Chemistry 172]

[0555]

[0556] [Chemistry 173]

[0557]

[0558] [Chemistry 174]

[0559]

[0560] [Chemistry 175]

[0561]

[0562] [Chemistry 176]

[0563]

[0564] [Chemistry 177]

[0565]

[0566] [Chemistry 178]

[0567]

[0568] [Chemistry 179]

[0569]

[0570] [Chemistry 180]

[0571]

[0572] [Chemistry 181]

[0573]

[0574] [Chemical Formula 182]

[0575]

[0576] [Chemical Formula 183]

[0577]

[0578] [Chemical Formula 184]

[0579]

[0580] [Chemical Formula 185]

[0581]

[0582] [Chemical Formula 186]

[0583]

[0584] [Chemical Formula 187]

[0585]

[0586] [Chemical Formula 188]

[0587]

[0588] [Chemical Formula 189]

[0589]

[0590] [Chemical Formula 190]

[0591]

[0592] [Chemical Formula 191]

[0593]

[0594] [Chemical Formula 192]

[0595]

[0596] [Chemical Formula 193]

[0597]

[0598] [Chemical Formula 194]

[0599]

[0600] [Chemical Formula 195]

[0601]

[0602] [Chemical formula 196]

[0603]

[0604] [Chemical formula 197]

[0605]

[0606] Specific examples of the oxonium cation represented by formula (cation-2) are listed below, but are not limited to these.

[0607] [Chemical formula 198]

[0608]

[0609] [Chemical formula 199]

[0610]

[0611] In formula (cation-3), R ct6 ~R ct9 are each independently a hydrocarbon group having 1 to 40 carbon atoms which may also contain a heteroatom. Further, R ct6 and R ct7 may also be bonded to each other and form a ring together with the nitrogen atom to which they are bonded. Specific examples of the aforementioned hydrocarbon group are the same as the examples exemplified for R ct1 ~R ct5 in the descriptions of formulas (cation-1) and (cation-2).

[0612] Specific examples of the ammonium cation represented by formula (cation-3) are listed below, but are not limited to these.

[0613] [Chemical formula 200]

[0614]

[0615] Specific examples of the onium salt represented by formula (1) or (2) are any combination of the aforementioned anions and cations. Further, these onium salts can be easily prepared by an ion exchange reaction using known organic chemical methods. For the ion exchange reaction, reference can be made to, for example, Japanese Patent Application Laid-Open No. 2007-145797.

[0616] The onium salt represented by formula (1) or (2) functions as a quencher in the chemically amplified resist composition of the present invention. This is because each counter anion of the aforementioned onium salt is a conjugate base of a weak acid. The weak acid referred to herein is an acid that exhibits an acidity such that it cannot deprotect the acid-labile group of the unit containing the acid-labile group in the base polymer. The onium salt represented by formula (1) or (2) functions as a quencher when used in combination with an onium salt type photoacid generator having a conjugate base of a strong acid such as α-position fluorinated sulfonic acid as a counter anion. That is, when an onium salt that generates a strong acid such as α-position fluorinated sulfonic acid is mixed with an onium salt that generates a weak acid such as non-fluorinated sulfonic acid or carboxylic acid, if the strong acid generated from the photoacid generator upon irradiation with high-energy rays collides with the unreacted onium salt having a weak acid anion, a weak acid is released due to salt exchange, and an onium salt having a strong acid anion is generated. In this process, the strong acid is exchanged for a weak acid with lower catalytic ability, so macroscopically the acid is inactivated and the control of acid diffusion can be carried out.

[0617] Furthermore, as the (B) quencher, an onium salt having a sulfonium cation and a phenoxide anion moiety within the same molecule described in Japanese Patent No. 6848776 can also be used. Furthermore, an onium salt having a sulfonium cation and a carboxylate anion moiety within the same molecule described in Japanese Patent No. 6583136 and Japanese Patent Application Laid-Open No. 2020-200311, and an onium salt having an iodonium cation and a carboxylate anion moiety within the same molecule described in Japanese Patent No. 6274755 can also be used.

[0618] Here, when the photoacid generator that generates a strong acid is an onium salt, as described above, the strong acid generated by irradiation with high-energy rays can be exchanged for a weak acid. On the other hand, it is considered that salt exchange due to the collision of the weak acid generated by irradiation with high-energy rays and the unreacted onium salt that generates a strong acid is not likely to occur. The reason is the phenomenon that the onium cation is more likely to form an ion pair with the anion of the strong acid.

[0619] When the chemically amplified resist composition of the present invention contains the onium salt represented by formula (1) or (2) as the (B) quencher, its content is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, relative to 80 parts by mass of the (A) base polymer. If the onium salt type quencher of the (B) component is within the aforementioned range, the resolution is good and the sensitivity does not decrease significantly, so it is ideal. The onium salt represented by formula (1) or (2) can be used alone or in combination of two or more.

[0620] The chemically amplified resist composition of the present invention may also contain a nitrogen-containing compound as the (B) quencher. Examples of the nitrogen-containing compound as the component (B) include primary, secondary, or tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103, particularly amine compounds having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate bond. Further, compounds in which a primary or secondary amine is protected with a carbamate group, such as those described in JP-B-3790649, may also be mentioned. Moreover, compounds having an acid-labile group in the molecule, such as those described in JP-A-2009-109595, may also be mentioned.

[0621] Further, a sulfonium salt of a sulfonic acid having a nitrogen-containing substituent may also be used as the nitrogen-containing compound. Such a compound acts as a quencher in the unexposed portion, and in the exposed portion, it loses its quencher ability due to neutralization with the acid generated by itself and acts as a so-called photo-destructible base. By using a photo-destructible base, the contrast between the exposed portion and the unexposed portion can be further enhanced. For photo-destructible bases, reference can be made to, for example, JP-A-2009-109595, JP-A-2012-46501, etc.

[0622] When the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as the (B) quencher, its content is preferably 0.001 to 12 parts by mass, more preferably 0.01 to 8 parts by mass, relative to 80 parts by mass of the (A) base polymer. The aforementioned nitrogen-containing compound may be used alone or in combination of two or more.

[0623] [(C) Organic solvent]

[0624] The chemically amplified resist composition of the present invention may also contain an organic solvent as the (C) component. The (C) organic solvent is not particularly limited as long as it can dissolve the aforementioned respective components and the components described later. 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, tert-butyl acetate, tert-butyl propionate, and propylene glycol monoter-butyl ether acetate; lactones such as GBL; and mixed solvents thereof.

[0625] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and their mixed solvents, which are particularly excellent in dissolving the base polymer as the (A) component, are preferred.

[0626] In the chemically amplified resist composition of the present invention, the content of the (C) organic solvent is preferably 200 to 5000 parts by mass, more preferably 400 to 3500 parts by mass, relative to 80 parts by mass of the (A) base polymer. The (C) organic solvent can be used alone or in combination of two or more.

[0627] [(D) Acid generator]

[0628] The chemically amplified resist composition of the present invention may also contain an acid generator within the range that does not impair the effects of the present invention. The aforementioned acid generator is, for example, a compound that generates an acid upon exposure to actinic light or radiation (photoacid generator). The photoacid generator is not particularly limited as long as it is a compound that generates an acid upon irradiation with high-energy rays, and those that generate sulfonic acid, imidic acid, or methylated acid are preferred. Preferred photoacid generators include sulfonium salts, iodonium salts, sulfonyl diazomethane, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, etc. Specific examples of the acid generator are those described in paragraphs

[0122] to

[0142] of Japanese Patent Laid-Open No. 2008-111103.

[0629] Also, it is preferable to use a sulfonium salt represented by the following formula (3-1) and an iodonium salt represented by the following formula (3-2) as the photoacid generator.

[0630] [Chemical formula 201]

[0631]

[0632] In formulas (3-1) and (3-2), R 101 ~R 105 are each independently a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. Specific examples of the aforementioned halogen atom and hydrocarbon group are the same as those exemplified for the halogen atom and hydrocarbon group represented by R ct1 ~R ct5 in the description of formulas (cation-1) and (cation-2). Also, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be replaced by a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of the -CH2- of the aforementioned hydrocarbon group may be replaced by a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. Also, R 101 and R 102 may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. Specific examples of the ring formed at this time are the same as those exemplified for R ct1 and R ct2 in the description of formula (cation-1).Examples of rings that can be formed together by bonding to each other and to the sulfur atoms to which they are bonded are the same examples.

[0633] Specific examples of the cations of the sulfonium salts represented by formula (3-1) are the same examples as those exemplified for the sulfonium cations represented by formula (cation-1). Also, specific examples of the cations of the oxosulfonium salts represented by formula (3-2) are the same examples as those exemplified for the oxosulfonium cations represented by formula (cation-2).

[0634] In formulas (3-1) and (3-2), Xa - is an anion selected from the following formulas (3A) to (3D).

[0635] [Chemical formula 202]

[0636]

[0637] In formula (3A), R fa is a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof are the same examples as those exemplified in the description of R fa1 below formula (3A').

[0638] The anion represented by formula (3A) is preferably the one represented by the following formula (3A').

[0639] [Chemical formula 203]

[0640]

[0641] In formula (3A'), R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group.

[0642] In formula (3A'), R fa1 is a hydrocarbon group having 1 to 38 carbon atoms which may contain a heteroatom. The aforementioned heteroatom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc., and more preferably an oxygen atom. Considering the viewpoint of obtaining high resolution in fine pattern formation, the aforementioned hydrocarbon group preferably has 6 to 30 carbon atoms.

[0643] R fa1The hydrocarbon group having 1 to 38 carbon atoms represented may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 38 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, eicosyl, etc.; cycloaliphatic saturated hydrocarbon groups having 3 to 38 carbon atoms such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecyl, tetracyclododecyl, tetracyclododecylmethyl, dicyclohexylmethyl, etc.; unsaturated aliphatic hydrocarbon groups having 2 to 38 carbon atoms such as allyl, 3-cyclohexenyl, etc.; aryl groups having 6 to 38 carbon atoms such as phenyl, 1-naphthyl, 2-naphthyl, etc.; aralkyl groups having 7 to 38 carbon atoms such as benzyl, diphenylmethyl, etc.; groups obtained by combining them, etc.

[0644] Furthermore, some or all of the hydrogen atoms of the aforementioned hydrocarbon group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a part of -CH2- of the aforementioned hydrocarbon group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc. As a result, it may also contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. Furthermore, it is preferable that the aforementioned heteroatom is an oxygen atom. Specific examples of the hydrocarbon group containing a heteroatom include tetrahydrofuranyl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamidomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, 3-oxocyclohexyl, etc.

[0645] Regarding the synthesis of the sulfonium salt containing the anion represented by the formula (3A'), refer to Japanese Patent Application Laid-Open No. 2007-145797, Japanese Patent Application Laid-Open No. 2008-106045, Japanese Patent Application Laid-Open No. 2009-7327, Japanese Patent Application Laid-Open No. 2009-258695, etc. Furthermore, the sulfonium salts described in Japanese Patent Application Laid-Open No. 2010-215608, Japanese Patent Application Laid-Open No. 2012-41320, Japanese Patent Application Laid-Open No. 2012-106986, Japanese Patent Application Laid-Open No. 2012-153644, etc. are also preferably used.

[0646] Specific examples of the anion represented by the formula (3A) are listed below, but are not limited to these. Furthermore, in the following formula, Ac is an acetyl group.

[0647] [Chemical formula 204]

[0648]

[0649] [Chemical formula 205]

[0650]

[0651] [Chemical formula 206]

[0652]

[0653] [Chemical formula 207]

[0654]

[0655] In formula (3B), R fb 1 and R fb2 are each independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may also contain a heteroatom. The aforementioned hydrocarbon group may be saturated, unsaturated, linear, branched, or cyclic. Specific examples thereof are the same as the examples exemplified for the hydrocarbon group represented by R fa1 in formula (3A'). R fb1 and R fb2 are preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. Also, R fb1 and R fb2 may also be bonded to each other and together with the group (-CF2-SO2-N - -SO2-CF2-) to which they are bonded form a ring. In this case, the group obtained by bonding R fb 1 and R fb2 to each other is preferably a fluoroethylene or fluoropropylene group.

[0656] In formula (3C), R fc1 , R fc2 and R fc3 are each independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may also contain a heteroatom. The aforementioned hydrocarbon group may be saturated, unsaturated, linear, branched, or cyclic. Specific examples thereof are the same as the examples exemplified for the hydrocarbon group represented by R fa1 in formula (3A'). R fc1 , R fc2 and R fc3 are preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. Also, R fc1 and R fc2 may also be bonded to each other and together with the group (-CF2-SO2-C - -SO2-CF2-) to which they are bonded form a ring. In this case, the group obtained by bonding R fc1 and R fc2 to each other is preferably a fluoroethylene or fluoropropylene group.

[0657] In formula (3D), R fdis a hydrocarbon group having 1 to 40 carbon atoms which may also contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof are the same as the hydrocarbon groups exemplified for R in formula (3A'). fa1 The hydrocarbon groups represented are the same examples as those exemplified.

[0658] For the synthesis of sulfonium salts containing anions represented by formula (3D), see Japanese Patent Application Laid-Open No. 2010-215608 and Japanese Patent Application Laid-Open No. 2014-133723.

[0659] Specific examples of the anion represented by formula (3D) are listed below, but are not limited thereto.

[0660] [Chemical formula 208]

[0661]

[0662] [Chemical formula 209]

[0663]

[0664] Also, the photoacid generator containing an anion represented by formula (3D) has no fluorine atom at the α-position of the sulfo group, but has two trifluoromethyl groups at the β-position, and thus has sufficient acidity required to cleave the acid-labile group in the base polymer. Therefore, it can be used as a photoacid generator.

[0665] A photoacid generator is also preferably one represented by the following formula (4).

[0666] [Chemical formula 210]

[0667]

[0668] In formula (4), R 201 and R 202 are each independently a hydrocarbon group having 1 to 30 carbon atoms which may also contain a heteroatom. R 203 is a divalent hydrocarbon group having 1 to 30 carbon atoms which may also contain a heteroatom. Also, any two of R 201 , R 202 and R 203 may be bonded to each other and together with the sulfur atom to which they are bonded form a ring. At this time, specific examples of the aforementioned ring are the same as the rings exemplified for R ct1 and R ct2 which may be bonded to each other and together with the sulfur atom to which they are bonded to form a ring.

[0669] R 201 and R 202The hydrocarbon group having 1 to 30 carbon atoms represented may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, etc.; cycloaliphatic saturated hydrocarbon groups having 3 to 30 carbon atoms such as cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, tricyclo[5.2.1.0 2,6 decyl, adamantyl, etc.; aryl groups having 6 to 30 carbon atoms such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, tert-butylnaphthyl, anthryl, etc.; groups obtained by combining them, etc. Further, some or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a part of -CH2- of the aforementioned hydrocarbon group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0670] R 203The C1-C30 alkylene group represented may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include C1-C30 alkylene groups such as 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, heptadecane-1,17-diyl; C3-C30 cycloaliphatic saturated alkylene groups such as cyclopentanediyl, cyclohexanediyl, norbornanediyl, adamantanediyl; C6-C30 arylene groups such as phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, n-propylnaphthylene, isopropylnaphthylene, n-butylnaphthylene, isobutylnaphthylene, sec-butylnaphthylene, tert-butylnaphthylene; groups obtained by combining them, etc. Further, some or all of the hydrogen atoms of the aforementioned alkylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a part of -CH2- of the aforementioned alkylene group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. The aforementioned heteroatom is preferably an oxygen atom.

[0671] In formula (4), L 1 is a single bond, an ether bond, or a C1-C20 alkylene group which may contain a heteroatom. The aforementioned alkylene group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof are the same as the examples exemplified for the alkylene group represented by R 203 .

[0672] In formula (4), X a , X b , X c and X d are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group. However, at least one of X a , X b , X c and X d is a fluorine atom or a trifluoromethyl group.

[0673] In formula (4), k is an integer from 0 to 3.

[0674] The photoacid generator represented by formula (4) is preferably the one represented by the following formula (4').

[0675] [Chemical formula 211]

[0676]

[0677] In formula (4'), L 1 is as described above. X e is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R 301 , R 302 and R 303 are each independently a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof are the same as the examples exemplified for the hydrocarbon group represented by R fa1 in formula (3A'). x and y are each independently an integer from 0 to 5. z is an integer from 0 to 4.

[0678] Specific examples of the photoacid generator represented by formula (4) are the same as the examples exemplified for the photoacid generator represented by formula (2) in Japanese Patent Laid-Open No. 2017-26980.

[0679] Among the aforementioned photoacid generators, those containing an anion represented by formula (3A') or (3D) have small acid diffusion and excellent solubility in solvents, and are particularly desirable. Also, those represented by formula (4') have extremely small acid diffusion and are particularly desirable.

[0680] Also, as other acid generators, sulfonium salts and iodonium salts containing an anion having an iodine atom-substituted aromatic ring represented by the following formula (5-1) or (5-2) can be used.

[0681] [Chemical formula 212]

[0682]

[0683] In formula (5-1) and (5-2), p is 1, 2 or 3. q and r are integers satisfying 1 ≤ q ≤ 5, 0 ≤ r ≤ 3 and 1 ≤ q + r ≤ 5. It is more desirable that q is 1, 2 or 3, and even more desirable that q is 2 or 3. It is preferable that r is 0, 1 or 2.

[0684] In formula (5-1) and (5-2), L 11 is a single bond, an ether bond or an ester bond, or a saturated alkylene group having 1 to 6 carbon atoms which may also contain an ether bond or an ester bond. The aforementioned saturated alkylene group may be linear, branched or cyclic.

[0685] In formula (5-1) and (5-2), L 12When p is 1, it is a single bond or a divalent linking group having 1 to 20 carbon atoms, and when p is 2 or 3, it is a (p + 1)-valent linking group having 1 to 20 carbon atoms. This linking group may also contain an oxygen atom, a sulfur atom or a nitrogen atom.

[0686] In formulas (5-1) and (5-2), R 401 is a hydroxyl group, a carboxyl group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbon oxy group having 1 to 20 carbon atoms, a hydrocarbon carbonyl group having 2 to 20 carbon atoms, a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbon carbonyloxy group having 2 to 20 carbon atoms or a hydrocarbon sulfonyloxy group having 1 to 20 carbon atoms, which may also contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, an amino group or an ether bond, or -N(R 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D or -N(R 401 C )-C(=O)-O-R 401D . R 401A and R 401B are each independently a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. R 401C is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms, which may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms or a saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms. R 401D is an aliphatic hydrocarbon group having 1 to 16 carbon atoms, an aryl group having 6 to 14 carbon atoms or an aralkyl group having 7 to 15 carbon atoms, which may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms or a saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms. The aforementioned aliphatic hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. The aforementioned hydrocarbon group, hydrocarbon oxy group, hydrocarbon carbonyl group, hydrocarbon oxycarbonyl group, hydrocarbon carbonyloxy group and hydrocarbon sulfonyloxy group may be linear, branched or cyclic. When p and / or r is 2 or more, each R 401 may be the same or different from each other.

[0687] Among these, R 401 is preferably a hydroxyl group, -N(R 401C )-C(=O)-R 401D , -N(R 401C )-C(=O)-O-R 401D , a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group or the like.

[0688] In formulas (5-1) and (5-2), Rf 11 to Rf 14 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one of these is a fluorine atom or a trifluoromethyl group. Also, Rf 11 and Rf12 They can also be combined to form a carbonyl group. In particular, Rf 13 and Rf 14 are preferably both fluorine atoms.

[0689] In formulas (5-1) and (5-2), R 402 ~R 406 are each independently a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may also contain heteroatoms. The aforementioned hydrocarbon group may be saturated, unsaturated, linear, branched or cyclic. Specific examples thereof are the same as those exemplified for R ct1 ~R ct5 in the description of formulas (cation-1) and (cation-2). Also, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted with a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone ring, a sulfo group or a group containing a sulfonium salt, and a part of -CH2- of the aforementioned hydrocarbon group may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond or a sulfonate bond. Also, R 402 and R 403 may also be bonded to each other and together with the sulfur atom to which they are bonded form a ring. In this case, specific examples of the aforementioned ring are the same as those exemplified for the ring that can be formed by R ct1 and R ct2 being bonded to each other and together with the sulfur atom to which they are bonded in the description of formula (cation-1).

[0690] Specific examples of the cation of the sulfonium salt represented by formula (5-1) are the same as those exemplified for the sulfonium cation represented by formula (cation-1). Also, specific examples of the cation of the oxonium salt represented by formula (5-2) are the same as those exemplified for the oxonium cation represented by formula (cation-2).

[0691] Specific examples of the anion of the onium salt represented by formula (5-1) or (5-2) are listed below, but are not limited to these.

[0692] [Chemical formula 213]

[0693]

[0694] [Chemical formula 214]

[0695]

[0696] [Chemical formula 215]

[0697]

[0698] [Chemical formula 216]

[0699]

[0700] [Chemical 217]

[0701]

[0702] [Chemical 218]

[0703]

[0704] [Chemical 219]

[0705]

[0706] [Chemical 220]

[0707]

[0708] [Chemical 221]

[0709]

[0710] [Chemical 222]

[0711]

[0712] [Chemical 223]

[0713]

[0714] [Chemical 224]

[0715]

[0716] [Chemical 225]

[0717]

[0718] [Chemical 226]

[0719]

[0720] [Chemical 227]

[0721]

[0722] [Chemical 228]

[0723]

[0724] [Chemical 229]

[0725]

[0726] [Chemical 230]

[0727]

[0728] [Chemical formula 231]

[0729]

[0730] [Chemical formula 232]

[0731]

[0732] [Chemical formula 233]

[0733]

[0734] [Chemical formula 234]

[0735]

[0736] When the chemically amplified resist composition of the present invention contains a (D) acid generator, its content is preferably 0.1 to 40 parts by mass, more preferably 0.5 to 20 parts by mass, relative to 80 parts by mass of the (A) base polymer. If the addition amount of the acid generator as the (D) component is within the above range, the resolution is good, and there is no problem of foreign matter generation during or after the development of the resist film or when peeling, so it is ideal. The (D) acid generator can be used alone or in combination of two or more.

[0737] [(E) surfactant]

[0738] The chemically amplified resist composition of the present invention may further contain a surfactant as the (E) component. The (E) surfactant is preferably a surfactant that is insoluble or hardly soluble in water and soluble in an alkali developing solution, or a surfactant that is insoluble or hardly soluble in both water and an alkali developing solution. Such surfactants can be referred to those described in Japanese Patent Application Laid-Open No. 2010-215608 and Japanese Patent Application Laid-Open No. 2011-16746.

[0739] Surfactants that are insoluble or hardly soluble in both water and an alkali developing solution are preferably FC-4430 (manufactured by 3M Company), surflon (registered trademark) S-381 (manufactured by AGC Seimichemical Co., Ltd.), OLFINE (registered trademark) E1004 (manufactured by Nissin Chemical Industry Co., Ltd.), KH-20, KH-30 (manufactured by AGC Seimi chemical Co., Ltd.), and oxetane ring-opening polymers represented by the following formula (surf-1) among the surfactants described in the above-mentioned publications.

[0740] [Chemical formula 235]

[0741]

[0742] Here, R, Rf, A, B, C, m, n have nothing to do with the foregoing description and are only applicable to formula (surf-1). R is an aliphatic group with a valence of 2 to 4 and a carbon number of 2 to 5. For the foregoing aliphatic group, examples of the divalent group include ethylene, 1,4-butylene, 1,2-propylene, 2,2-dimethyl-1,3-propylene, 1,5-pentylene, etc., and examples of the trivalent or tetravalent group are as follows.

[0743] [Chemical formula 236]

[0744]

[0745] In the formula, the dashed line is an atomic bond, and each is a partial structure derived from glycerol, trimethylolethane, trimethylolpropane, or pentaerythritol.

[0746] Among these, 1,4-butylene, 2,2-dimethyl-1,3-propylene, etc. are preferred.

[0747] 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. Also, the arrangement of each constituent unit in formula (surf-1) is not specified and can be block-bonded or randomly bonded. For the manufacture of the surfactant of the partially fluorinated oxetane ring-opening polymer system, refer to the specification of U.S. Patent No. 5650483, etc.

[0748] For a surfactant that is insoluble or hardly soluble in water and soluble in an alkali developer, when no resist protective film is used in ArF immersion lithography, it has the effect of reducing the infiltration and leaching of water by aligning on the surface of the resist film. Therefore, it is useful for suppressing the dissolution of water-soluble components from the resist film and reducing damage to the exposure apparatus. Also, it can be solubilized during development with an aqueous alkali solution after exposure or post-exposure bake (PEB), and it is not easily a foreign substance that causes defects, so it is useful. Such a surfactant has the property of being insoluble or hardly soluble in water and soluble in an alkali developer and is a polymer-type surfactant, also called a hydrophobic resin. In particular, those with high water repellency and improved lubricity are preferred.

[0749] Specific examples of such a polymer-type surfactant include, for example, those containing at least one kind of repeating unit selected from the repeating units represented by the following formula (6A) to (6E).

[0750] [Chemical formula 237]

[0751]

[0752] In formula (6A) to (6E), R Bis a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. W 1 is -CH2-, -CH2CH2-, -O- or two -H's separated from each other. R s1 Each independently is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R s2 is a single bond or a linear or branched alkylene group having 1 to 5 carbon atoms. R s3 Each independently is a hydrogen atom, a hydrocarbon group or a fluorinated hydrocarbon group having 1 to 15 carbon atoms, or an acid-labile group. R s3 When it is a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group may be inserted between carbon-carbon bonds. R s4 is a (u + 1)-valent hydrocarbon group or a fluorinated hydrocarbon group having 1 to 20 carbon atoms. u is an integer from 1 to 3. R s5 Each independently is a hydrogen atom or a group represented by -C(=O)-O-R sa R sa is a fluorinated hydrocarbon group having 1 to 20 carbon atoms. R s6 is a hydrocarbon group or a fluorinated hydrocarbon group having 1 to 15 carbon atoms, and an ether bond or a carbonyl group may be inserted between carbon-carbon bonds thereof.

[0753] R s1 The hydrocarbon group having 1 to 10 carbon atoms represented by R is preferably a saturated hydrocarbon group, and may be any of linear, branched and cyclic. Specific examples thereof include alkyl groups having 1 to 10 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl; cycloaliphatic saturated hydrocarbon groups having 3 to 10 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, norbornyl. Among these, those having 1 to 6 carbon atoms are preferred.

[0754] R s2 The alkylene group represented by R is preferably a saturated alkylene group, and may be any of linear, branched and cyclic. Specific examples thereof include methylene, ethylene, propylene, butylene, pentylene and the like.

[0755] R s3 or R s6 The hydrocarbon group represented by R may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include saturated hydrocarbon groups, aliphatic unsaturated hydrocarbon groups such as alkenyl and alkynyl, etc., but saturated hydrocarbon groups are preferred. Specific examples of the aforementioned saturated hydrocarbon groups are those exemplified for the hydrocarbon group represented by R s1 In addition to those exemplified, for example, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl and the like. R s3 or R s6 Specific examples of the fluorinated hydrocarbon group represented by R are groups in which a part or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbon group are substituted with fluorine atoms. As described above, an ether bond or a carbonyl group may also be inserted between these carbon-carbon bonds.

[0756] Rs3 Specific examples of the acid-labile group represented include groups represented by the aforementioned formulas (AL-3) to (AL-5), trialkylsilyls in which each alkyl group is an alkyl group having 1 to 6 carbon atoms, alkyl groups having an oxygenated group and having 4 to 20 carbon atoms, and the like.

[0757] R s4 The (u + 1)-valent hydrocarbon group or fluorinated hydrocarbon group represented may be linear, branched, or cyclic, and specific examples thereof include groups obtained by removing u more hydrogen atoms from the aforementioned hydrocarbon group or fluorinated hydrocarbon group.

[0758] R sa The fluorinated hydrocarbon group represented is preferably saturated and may be any of linear, branched, or cyclic. Specific examples thereof include those in which part or all of the hydrogen atoms of the aforementioned hydrocarbon group are replaced by fluorine atoms, and specific examples include 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-dodecafluoroheptyl, 2-(perfluorobutyl)ethyl, 2-(perfluorohexyl)ethyl, 2-(perfluorooctyl)ethyl, 2-(perfluorodecyl)ethyl, and the like.

[0759] Specific examples of the repeating unit represented by any one of formulas (6A) to (6E) are listed below, but are not limited thereto. Also, in the following formula, R B As described above.

[0760] [Chemical formula 238]

[0761]

[0762] [Chemical formula 239]

[0763]

[0764] [Chemical formula 240]

[0765]

[0766] [Chemical formula 241]

[0767]

[0768] [Chemical formula 242]

[0769]

[0770] The aforementioned polymeric surfactant may further contain repeating units other than the repeating units represented by formulas (6A) to (6E). Specific examples of the other repeating units include repeating units obtained from methacrylic acid, α-trifluoromethyl methacrylic acid derivatives, and the like. In the polymeric surfactant, the content of the repeating units represented by formulas (6A) to (6E) is preferably 20 mol% or more, more preferably 60 mol% or more, and still more preferably 100 mol% of all the repeating units.

[0771] The Mw of the aforementioned polymeric surfactant is preferably 1,000 to 500,000, and more preferably 3,000 to 100,000. The Mw / Mn is preferably 1.0 to 2.0, and more preferably 1.0 to 1.6.

[0772] Regarding the method for synthesizing the aforementioned polymeric surfactant, for example, a method of polymerizing an unsaturated bond-containing monomer that gives the repeating units represented by formulas (6A) to (6E) and, if necessary, gives other repeating units, in an organic solvent, adding a radical initiator and heating it. Specific examples of the organic solvent used in the polymerization include toluene, benzene, THF, diethyl ether, dioxane, and the like. Specific examples of the polymerization initiator include AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, lauroyl peroxide, and the like. The reaction temperature is preferably 50 to 100 °C. The reaction time is preferably 4 to 24 hours. Those in which an acid-labile group has been introduced into the monomer can be directly used, or protection or partial protection can also be carried out after polymerization.

[0773] When synthesizing the aforementioned polymeric surfactant, in order to adjust the molecular weight, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol can also be used. At this time, the addition amount of these chain transfer agents is preferably 0.01 to 10 mol% relative to the total molar amount of the monomers to be polymerized.

[0774] When the chemically amplified resist composition of the present invention contains (E) a surfactant, its content is preferably 0.1 to 50 parts by mass, and more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of (A) the base polymer. If the content of (E) the surfactant is 0.1 part by mass or more, the receding contact angle between the resist film surface and water is sufficiently increased. If it is 50 parts by mass or less, the dissolution rate of the resist film surface in the developer is small, and the height of the formed fine pattern can be sufficiently ensured. (E) The surfactant can be used alone or in combination of two or more.

[0775] [(F) Dissolution inhibitor]

[0776] The chemically amplified resist composition of the present invention may further contain a dissolution inhibitor as the (F) component. When the chemically amplified resist composition of the present invention is a positive type, by blending a dissolution inhibitor, the difference in dissolution rate between the exposed portion and the unexposed portion can be further increased, and the resolution can be further improved.

[0777] Specific examples of the aforementioned dissolution inhibitor include: a compound having a molecular weight preferably of 100 to 1,000, more preferably 150 to 800 and having two or more phenolic hydroxyl groups in the molecule, wherein the hydrogen atoms of the phenolic hydroxyl groups are substituted by acid-labile groups in a proportion of 0 to 100 mol% in total, or a compound having a carboxyl group in the molecule, wherein the hydrogen atoms of the carboxyl group are substituted by acid-labile groups in an average proportion of 50 to 100 mol% in total. Specifically, bisphenol A, triphenol, phenolphthalein, cresol novolak, naphthoic acid, adamantane carboxylic acid, compounds in which the hydrogen atoms of the hydroxyl groups and carboxyl groups of cholic acid are substituted by acid-labile groups, etc. can be cited. For example, those described in paragraphs

[0155] to

[0178] of Japanese Patent Laid-Open No. 2008-122932.

[0778] When the chemically amplified resist composition of the present invention contains the (F) dissolution inhibitor, its content is preferably 0 to 50 parts by mass, more preferably 5 to 40 parts by mass, relative to 80 parts by mass of the (A) base polymer. The (F) dissolution inhibitor may be used alone or in combination of two or more.

[0779] [(G) Other components]

[0780] The chemically amplified resist composition of the present invention may also contain a compound that decomposes by an acid and generates an acid (acid-proliferating compound), an organic acid derivative, a fluorine-substituted alcohol, a water-repellent improver, etc. as the (G) other components. The aforementioned acid-proliferating compound can be referred to the compounds described in Japanese Patent Laid-Open No. 2009-269953 or Japanese Patent Laid-Open No. 2010-215608. When the acid-proliferating compound is contained, its content is preferably 0 to 5 parts by mass, more preferably 0 to 3 parts by mass, relative to 80 parts by mass of the (A) base polymer. If the content is too large, it is difficult to control the acid diffusion, and deterioration of resolution and pattern shape may occur. The aforementioned organic acid derivative and fluorine-substituted alcohol can be referred to the compounds described in Japanese Patent Laid-Open No. 2009-269953 or Japanese Patent Laid-Open No. 2010-215608.

[0781] The aforementioned water repellency improver can be used in immersion lithography without using a top coat. It is preferable that the aforementioned water repellency improver is a polymer containing a fluorinated alkyl group, a polymer containing 1,1,1,3,3,3-hexafluoro-2-propanol residues with a specific structure, etc., and those exemplified in Japanese Patent Laid-Open No. 2007-297590, Japanese Patent Laid-Open No. 2008-111103, etc. are more preferable. The aforementioned water repellency improver needs to be soluble in an alkali developer and an organic solvent developer. The aforementioned specific water repellency improver having 1,1,1,3,3,3-hexafluoro-2-propanol residues has good solubility in the developer. Regarding the water repellency improver, a polymer containing repeating units of amino groups and amine salts has a high effect of preventing the evaporation of acid in PEB and preventing the opening defect of the hole pattern after development. When the chemically amplified resist composition of the present invention contains the aforementioned water repellency improver, its content is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of the (A) base polymer.

[0782] [Pattern formation method]

[0783] When the chemically amplified resist composition of the present invention is used in various integrated circuit manufacturing processes, known lithography techniques can be employed. For example: a pattern formation method, such as a method including the following steps: forming a resist film on a substrate using the aforementioned chemically amplified resist composition; exposing the aforementioned resist film to high-energy rays; and developing the exposed resist film using a developer.

[0784] First, the chemically amplified resist composition of the present invention is coated on a substrate for integrated circuit manufacturing (such as Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflection film, etc.) or a substrate for mask circuit manufacturing (such as Cr, CrO, CrON, MoSi2, SiO2, etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, blade coating, etc., so that the coating film thickness becomes 0.01 to 2.0 μm. It is prebaked on a hot plate, preferably at 60 to 150 °C for 10 seconds to 30 minutes, more preferably at 80 to 120 °C for 30 seconds to 20 minutes, to form a resist film.

[0785] Next, the aforementioned resist film is exposed to high-energy rays. The aforementioned high-energy rays are, for example, ultraviolet rays, far ultraviolet rays, EB, EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer lasers, γ-rays, synchrotron radiation, etc. When the aforementioned high-energy rays are ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer lasers, γ-rays, synchrotron radiation, etc., irradiation is performed directly or using a mask for forming a target pattern, so that the exposure dose is preferably about 1 to 200 mJ / cm 2 , more preferably about 10 to 100 mJ / cm 2When the high-energy ray used is EB, it is directly drawn or drawn using a mask for forming a target pattern so that the exposure amount is preferably about 0.1 to 100 μC / cm 2 , more preferably about 0.5 to 50 μC / cm 2 . The chemically amplified resist composition of the present invention is particularly suitable for fine patterning by an ArF excimer laser having a wavelength of 193 nm, a KrF excimer laser having a wavelength of 248 nm, EB, EUV having a wavelength of 3 to 15 nm, X-rays, soft X-rays, γ-rays, or synchrotron radiation in high-energy rays.

[0786] After exposure, on a hot plate, PEB can preferably be carried out under the conditions of 60 to 150 °C for 10 seconds to 30 minutes, more preferably 80 to 120 °C for 30 seconds to 20 minutes.

[0787] After exposure or after PEB, a developer of an aqueous alkali solution such as 0.1 to 10% by mass, preferably 2 to 5% by mass of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc. is used, and development is carried out for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes by a conventional method such as the dip method, the puddle method, or the spray method. The irradiated part is dissolved in the developer, and the unexposed part is not dissolved, and a target positive pattern is formed on the substrate.

[0788] Instead of using the aforementioned aqueous alkali solution, an organic solvent developer can also be used to obtain a negative pattern. Specific examples of the developer used at this time are, for example, 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butenyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, 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 phenylacetate, 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 combination of two or more.

[0789] Rinsing can also be carried out at the end of development. The rinsing liquid is preferably a solvent that is miscible with the developer and does not dissolve the resist film. For such a solvent, an alcohol having 3 to 10 carbon atoms, an ether compound having 8 to 12 carbon atoms, an alkane, alkene, alkyne, or aromatic solvent having 6 to 12 carbon atoms is ideal.

[0790] Specific examples of the alcohol having 3 to 10 carbon atoms include n-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, tert-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, and the like.

[0791] Specific examples of the ether compound having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, di-n-hexyl ether, and the like.

[0792] Specific examples of the alkane having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, and the like. Specific examples of the alkene having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, and the like. Specific examples of the alkyne having 6 to 12 carbon atoms include hexyne, heptyne, octyne, and the like.

[0793] Specific examples of the aromatic solvent include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, mesitylene, and the like.

[0794] By performing rinsing, the collapse of the resist pattern and the occurrence of defects can be reduced. Further, rinsing is not necessary, and by not performing rinsing, the amount of solvent used can be reduced.

[0795] The developed hole pattern and trench pattern can also be shrunk by using heat flow, RELACS technology, or DSA technology. A shrinkage agent is applied to the hole pattern, and by diffusion of an acid catalyst from the baking resist film, crosslinking of the shrinkage agent occurs on the surface of the resist film, and the shrinkage agent adheres to the sidewall of the hole pattern. The baking temperature is preferably 70 to 180 °C, more preferably 80 to 170 °C, and the baking time is preferably 10 to 300 seconds to remove the excess shrinkage agent and shrink the hole pattern.

[0796] [Examples]

[0797] Hereinafter, synthesis examples, examples, and comparative examples are given to specifically illustrate the present invention. The present invention is not limited by the following examples. Further, the apparatuses used are as follows.

[0798] ·MALDI TOF-MS: S3000 manufactured by JEOL Ltd.

[0799] [1] Synthesis of onium salt monomers

[0800] [Example 1-1] Synthesis of onium salt monomer a-1

[0801] [Chemical formula 243]

[0802]

[0803] (1) Synthesis of intermediate In-1

[0804] Under a nitrogen atmosphere, in a reaction vessel, raw material SM-1 (37.2 g), triethylamine (18.0 g), and 4-dimethylaminopyridine (1.50 g) were dissolved or suspended in THF (200 g), and cooled with an ice bath. Thereafter, a solution obtained by dissolving p-styrenesulfonyl chloride (16.4 g) in THF (50 g) was added dropwise. After the addition, the temperature inside the reaction vessel was raised to 50 °C and aged for 6 hours. Thereafter, the reaction solution was cooled, saturated aqueous sodium hydrogen carbonate (100 g) was added, and the reaction was stopped. The target product was extracted twice with ethyl acetate (200 g), subjected to a usual aqueous work-up, the solvent was distilled off, and then purified by silica gel chromatography to obtain 45.8 g of intermediate In-1 as an oil (yield 97%).

[0805] (2) Synthesis of intermediate In-2

[0806] Under a nitrogen atmosphere, intermediate In-1 (45.8 g) was dissolved in THF (200 g). While cooling with an ice bath, 25 mass% aqueous sodium hydroxide solution (15.5 g) was added dropwise. After the addition, the temperature inside the reaction vessel was raised to 30 °C and aged for 12 hours. After aging, the reaction solution was cooled, 20 mass% hydrochloric acid (18.2 g) was added dropwise, and the reaction was stopped. The target product was extracted twice with ethyl acetate (200 g), subjected to a usual aqueous work-up, the solvent was distilled off, and then recrystallized from hexane to obtain 37.5 g of intermediate In-2 as white crystals (yield 90%).

[0807] (3) Synthesis of intermediate In-3

[0808] Under a nitrogen atmosphere, in a reaction vessel, intermediate In-2 (37.5 g), raw material SM-2 (34.8 g), 4-dimethylaminopyridine (1.1 g), and dichloromethane (150 g) were added, and it was cooled in an ice bath. While maintaining the temperature inside the reaction vessel below 20 °C, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (20.1 g) was directly added in a powder state. After the addition, the temperature was raised to room temperature, and aging was carried out for 12 hours. After aging, water (100 g) was added to stop the reaction, and normal aqueous work-up was carried out. After distilling off the solvent, diisopropyl ether was added and recrystallization was carried out to obtain 61.5 g of intermediate In-3 as an oil (yield 89%).

[0809] (4) Synthesis of onium salt monomer a-1

[0810] Under a nitrogen atmosphere, in a reaction vessel, intermediate In-3 (61.5 g), raw material SM-3 (36.6 g), dichloromethane (200 g), and water (150 g) were added. After stirring for 30 minutes, the organic layer was separated and washed with water, and then concentrated under reduced pressure. The concentrated solution was purified by silica gel chromatography to obtain 71.6 g of the target onium salt monomer a-1 as an oil (yield 87%).

[0811] MALDI TOF-MS: POSITIVE M + 461 (equivalent to C 18 H 10 F4IS + )

[0812] NEGATIVE M - 766 (equivalent to C 18 H 10 F5I2O8 S2 - )

[0813] [Examples 1-2 to 1-7] Synthesis of onium salt monomers a-2 to a-7

[0814] Using the corresponding raw materials and known organic synthesis reactions, onium salt monomers a-2 to PAG monomers a-7 represented by the following formula were synthesized.

[0815] [Chemical formula 244]

[0816]

[0817] [Comparative Examples 1-1 to 1-4] Synthesis of comparative onium salt monomers ca-1 to ca-4

[0818] Using the corresponding raw materials and known organic synthesis reactions, comparative onium salt monomers ca-1 to ca-4 represented by the following formula were synthesized.

[0819] [Chemical 245]

[0820]

[0821] [2] Synthesis of Base Polymer

[0822] Among the monomers used in the synthesis of the base polymer, those other than monomers a-1 to a-7 and comparative monomers ca-1 to ca-4 are as follows.

[0823] [Chemical 246]

[0824]

[0825] [Chemical 247]

[0826]

[0827] [Chemical 248]

[0828]

[0829] [Example 2-1] Synthesis of Polymer P-1

[0830] Under a nitrogen atmosphere, 49.5 g of monomer a-1, 39.7 g of monomer b1-1, 11.5 g of monomer c-1, 3.67 g of V-601 (manufactured by Fuji Photo Film and Wako Pure Chemical Industries, Ltd.) and 139 g of MEK were measured in a flask to prepare a monomer-polymerization initiator solution. In another flask under a nitrogen atmosphere, 46 g of MEK was measured, heated to 80 °C with stirring, and the aforementioned monomer-polymerization initiator solution was added dropwise over 4 hours. After the addition was completed, the polymerization solution was continuously stirred at 80 °C for 2 hours and then cooled to room temperature. The obtained polymerization solution was added dropwise to 3000 g of vigorously stirred hexane, and the precipitated polymer was separated by filtration. The obtained polymer was washed twice with 600 g of hexane and then vacuum-dried at 50 °C for 20 hours to obtain white powdery polymer P-1 (yield 96.3 g, yield 96%). The Mw of polymer P-1 was 9500 and Mw / Mn was 1.72. Also, Mw was a polystyrene conversion measured value obtained by GPC using DMF as a solvent.

[0831] [Chemical 249]

[0832]

[0833] [Examples 2-2 to 2-20, Comparative Examples 2-1 to 2-10] Synthesis of Polymers P-2 to P-20 and Comparative Polymers CP-1 to CP-10

[0834] The polymers shown in Tables 1 and 2 were produced in the same manner as in Example 2-1, except that the types and blending ratios of the respective monomers were changed.

[0835] [Table 1]

[0836]

[0837]

[0838] [Table 2]

[0839]

[0840] [3] Preparation of chemically amplified resist compositions

[0841] [Examples 3-1 to 3-20, Comparative Examples 3-1 to 3-10]

[0842] Predetermined components selected from the base polymers (P-1 to P-20) of the present invention, comparative base polymers (CP-1 to CP-10), acid generators (PAG-1, PAG-2), and quenchers (SQ-1 to SQ-3, AQ-1) were dissolved in a solvent containing 0.01% by mass of FC-4430 manufactured by 3M Company as a surfactant according to the compositions shown in Tables 3 and 4 below to prepare a solution, and the solution was filtered through a 0.2-μm Teflon (registered trademark) filter to prepare chemically amplified resist compositions (R-1 to R-20, CR-1 to CR-10).

[0843] [Table 3]

[0844]

[0845] [Table 4]

[0846]

[0847]

[0848] In Tables 3 and 4, the solvent, quenchers (SQ-1 to SQ-3, AQ-1), and acid generators (PAG-1, PAG-2) are as follows.

[0849] · Solvent: PGMEA (propylene glycol monomethyl ether acetate)

[0850] DAA (diacetone alcohol)

[0851] · Quenchers: SQ-1 to SQ-3, AQ-1

[0852] [Chemical formula 250]

[0853]

[0854] · Acid generator: PAG-1, PAG-2

[0855] [Chemical formula 251]

[0856]

[0857] [4] EUV Lithography Evaluation (1)

[0858] [Examples 4-1 to 4-20, Comparative Examples 4-1 to 4-10]

[0859] Each chemically amplified resist composition (R-1 to R-20, CR-1 to CR-10) shown in Tables 3 and 4 was spin-coated on a Si substrate on which Shin-Etsu Chemical Co., Ltd.'s silicon-containing spin-on hard mask SHB-A940 (silicon content: 43 mass%) was formed with a film thickness of 20 nm, and pre-baked at 100 °C for 60 seconds using a hot plate to produce a resist film with a film thickness of 50 nm. For the aforementioned resist film, an EUV scanning exposure machine NXE3300 (NA 0.33, σ 0.9 / 0.6, dipole illumination) manufactured by ASML was used to perform exposure of an LS pattern with a size of 18 nm and a pitch of 36 nm on the wafer while changing the exposure dose and focus (exposure dose pitch: 1 mJ / cm 2 , focus pitch: 0.020 μm). After exposure, PEB was performed at the temperatures shown in Tables 5 and 6 for 60 seconds. Thereafter, immersion development was performed for 30 seconds with a 2.38 mass% TMAH aqueous solution, rinsing was performed with a rinsing material containing a surfactant, and spin-drying was performed to obtain a positive pattern.

[0860] The obtained LS pattern was observed with a length-measuring SEM (CG6300) manufactured by Hitachi High-Technologies Corporation, and sensitivity, EL, LWR, DOF, and collapse limit were evaluated according to the following methods. The results are shown in Tables 5 and 6.

[0861] [Sensitivity Evaluation]

[0862] The optimum exposure dose Eop (mJ / cm 2 ) for obtaining an LS pattern with a line width of 18 nm and a pitch of 36 nm was obtained and defined as the sensitivity. The smaller this value, the higher the sensitivity.

[0863] [EL Evaluation]

[0864] EL (unit: %) was calculated from the exposure doses within the range of ±10% (16.2 to 19.8 nm) of the 18 nm pitch width in the aforementioned LS pattern according to the following formula. The larger this value, the better the performance.

[0865] EL (%) = (|E1 - E2| / Eop) × 100

[0866] E1: Optimum exposure dose for an LS pattern with a line width of 16.2 nm and a pitch of 36 nm

[0867] E2: Optimum exposure dose for an LS pattern with a line width of 19.8 nm and a pitch of 36 nm

[0868] Eop: Optimum exposure dose for an LS pattern with a line width of 18 nm and a pitch of 36 nm

[0869] [LWR evaluation]

[0870] For the LS pattern irradiated with Eop, measure the dimensions at 10 positions in the longitudinal direction of the line. From the results, obtain three times the standard deviation (σ) (3σ) as the LWR. The smaller this value, the smaller the roughness and the more uniform the line width pattern obtained.

[0871] [DOF evaluation]

[0872] As the focus depth evaluation, obtain the focus range formed within the range of ±10% (16.2 - 19.8 nm) of the 18 nm dimension in the aforementioned LS pattern. The larger this value, the wider the focus depth.

[0873] [Evaluation of collapse limit of line pattern]

[0874] Measure the line dimensions of the optimum focus exposure doses of the aforementioned LS pattern at 10 positions in the longitudinal direction. The thinnest line dimension obtained without collapse is defined as the collapse limit dimension. The smaller this value, the better the collapse limit.

[0875] [Table 5]

[0876]

[0877] [Table 6]

[0878]

[0879] From the results shown in Tables 5 and 6, it can be seen that the chemically amplified resist composition using the base polymer containing the repeating unit of the onium salt monomer of the present invention has good sensitivity and excellent EL, LWR, and DOF. Also, it can be confirmed that the value of the collapse limit is small and the pattern is resistant to collapse even when forming fine patterns. Therefore, the chemically amplified resist composition representing the present invention is suitable as a material for EUV lithography.

[0880] [5] EUV lithography evaluation (2)

[0881] [Examples 5-1 to 5-20, Comparative Examples 5-1 to 5-10]

[0882] Each of the chemically amplified resist compositions (R-1 to R-20, CR-1 to CR-10) shown in Tables 3 and 4 was spin-coated on a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content: 43 mass%) manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a film thickness of 20 nm, and prebaked at 105 °C for 60 seconds using a hot plate to fabricate a resist film with a film thickness of 50 nm. It was exposed using an EUV scanning exposure apparatus NXE3400 (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, mask for hole pattern with a pitch of 46 nm and a +20% deviation in the on-wafer size) manufactured by ASML, PEB was performed at the temperatures described in Tables 7 and 8 for 60 seconds using a hot plate, and development was carried out for 30 seconds with a 2.38 mass% aqueous TMAH solution to form a hole pattern with a size of 23 nm.

[0883] Using a length-measuring SEM (CG6300) manufactured by Hitachi High-Technologies Corporation, the exposure dose at which the hole size was formed to be 23 nm was measured and defined as the sensitivity. Also, the sizes of 50 holes at this time were measured, and the three-fold value (3σ) of the standard deviation (σ) was calculated from the results and defined as the critical dimension uniformity (CDU). The results are shown in Tables 7 and 8.

[0884] [Table 7]

[0885]

[0886] [Table 8]

[0887]

[0888] From the results shown in Tables 7 and 8, it was confirmed that the chemically amplified resist composition of the present invention has good sensitivity and excellent CDU.

[0889] [6] Evaluation of dry etching resistance

[0890] [Examples 6-1 to 6-20, Comparative Examples 6-1 to 6-10]

[0891] 2 g of each of the polymers (polymers P-1 to P-20, comparative polymers CP-1 to CP-10) shown in Tables 1 and 2 were dissolved in 10 g of cyclohexanone, filtered through a filter with a size of 0.2 μm, and then the polymer solution was spin-coated on a Si substrate to form a film with a thickness of 300 nm and evaluated under the following conditions.

[0892] Etching test with CHF3 / CF4-based gas:

[0893] Using a dry etching apparatus TE-8500P manufactured by Tokyo Electron Limited, the film thickness difference of the polymer film before and after etching was determined.

[0894] The etching conditions are as follows.

[0895]

[0896] In this evaluation, those with a small film thickness difference, that is, those with a small reduction amount, represent high etching resistance.

[0897] The results of the dry etching resistance are shown in Tables 9 and 10.

[0898] [Table 9]

[0899]

[0900]

[0901] [Table 10]

[0902] Polymer <![CDATA[Etching rate of CHF3 / CF4-based gas (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 Example 6-7 CP-7 101 Comparative Example 6-8 CP-8 103 Comparative Example 6-9 CP-9 104 Comparative Example 6-10 CP-10 103

[0903] From the results shown in Tables 9 and 10, it can be confirmed that the polymer of the present invention has excellent dry etching resistance to CHF3 / CF4-based gases.

Claims

1. An onium salt monomer is composed of a cation represented by the following formula (a1) and a sulfonic acid anion containing a polymerizable group and no iodine atom. In the formula, 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; provided that 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, and when m2 is 1, 0 ≤ m7 + m10 ≤ 6; when m3 is 0, 1 ≤ m4 + m5 + m8 + m14 ≤ 4, and when m3 is 1, 1 ≤ m4 + m5 + m8 + m14 ≤ 6; when m11 is 0, 0 ≤ m12 + m13 ≤ 4, and when m11 is 1, 0 ≤ m12 + m13 ≤ 6; also, m4 + m12 ≥ 1. R F1 ~R F3 Each independently represents a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group having 1 to 6 carbon atoms; when m6 is 2 or more, each R F1 may be the same or different from each other, and when m7 is 2 or more, each R F2 may be the same or different from each other, and when m5 is 2 or more, each R F3 may be the same or different from each other; R 1 ~R 4 is a halogen atom other than iodine and fluorine atoms, a nitro group, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain heteroatoms, or a hydrocarbon thio group having 1 to 20 carbon atoms which may contain heteroatoms; when m8 is 2, two Rs 1 may be the same or different from each other, and two Rs 1 may also be bonded to each other and together with the carbon atoms to which they are bonded form a ring; when m9 is 2, two Rs 2 may be the same or different from each other, and two Rs 2 may also be bonded to each other and together with the carbon atoms to which they are bonded form a ring; when m10 is 2, two Rs 3 may be the same or different from each other, and two Rs 3 may also be bonded to each other and together with the carbon atoms to which they are bonded form a ring; when m13 is 2, two Rs 4 may be the same or different from each other, and two Rs 4 may also be bonded to each other and together with the carbon atoms to which they are bonded form a ring; Also, the aromatic rings directly bonded to and S in the sulfonium cation may also bond to each other to form a ring together with S; + The aromatic rings directly bonded to and S in the sulfonium cation may also bond to each other to form a ring together with S; + form a ring together; L A and L B each independently represents a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a sulfonamide bond, a carbonate bond or a carbamate bond; X L is a single bond or an alkylene group having 1 to 40 carbon atoms which may also contain a hetero atom.

2. The onium salt type monomer according to claim 1, wherein The structure of the anion is represented by any one of the following formulas (a2-1) to (a2-4). In the formula, 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; provided that when n3 = 0, 0 ≤ n4 + n5 ≤ 4, and when n3 = 1, 0 ≤ n4 + n5 ≤ 6. R A each independently is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; X A Each independently is a single bond, a phenylene group which may have substituents, a naphthylene group or *-C(=O)-O-X A1 -; X A1 is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the aliphatic alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring; X B Each independently is a single bond, **-X B1 -C(=O)-O-, **-C(=O)-NH-X B1 - or **-O-X B1 -; X B1 is an alkylene group having 1 to 20 carbon atoms which may also contain heteroatoms; X C Each independently is a single bond, ***-X C1 -C(=O)-O-, ***-C(=O)-NH-X C1 - or ***-O-X C1 -; X C1 is an alkylene group having 1 to 20 carbon atoms which may also contain heteroatoms; X D is a single bond, methylene, ethylene, phenylene, fluorophenylene, phenyl substituted with trifluoromethyl, *-C(=O)-O-X D1 -, *-C(=O)-N(H)-X D1 - or *-O-X D1 -; X D1 is an aliphatic alkylene group having 1 to 6 carbon atoms, phenylene, fluorophenylene or phenyl substituted with trifluoromethyl, and may also contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group; * represents the atomic bond between the carbon atoms of the main chain; ** represents the atomic bond with X A ; *** represents the atomic bond with X B ; R 5 is a hydrocarbon group having 1 to 20 carbon atoms which may also contain heteroatoms; when n5 is 2, 3 or 4, multiple Rs 5 may also be bonded to each other and together with the carbon atoms to which they are bonded form a ring; L C is a single bond, ether bond, ester bond, carbonyl group, sulfonate bond, carbonate bond or carbamate bond; Rf 1 and Rf 2 each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; Rf 3 and Rf 4 each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; Rf 5 and Rf 6 each independently represents a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; provided that not all of Rf 5 and Rf 6 simultaneously become hydrogen atoms; Rf 7 is a fluorine atom, a fluoroalkyl group having 1 to 6 carbon atoms, a fluoroalkoxy group having 1 to 6 carbon atoms, or a fluoroalkylthio group having 1 to 6 carbon atoms.

3. The onium salt type monomer according to claim 1, wherein The cation is represented by the following formula (a1-1). wherein, m4 to m10, m12 to m14, R F1 to R F3 、R 1 to R 4 、L A 、L B and X L are the same as described above.

4. The onium salt type monomer according to claim 3, wherein The cation is represented by the following formula (a1-2). where m4 to m10, R F1 ~R F3 and R 1 ~R 3 are as described above.

5. A monomeric photoacid generator is composed of the onium salt monomer according to any one of claims 1 to 4.

6. A polymer contains repeating units derived from the monomeric photoacid generator according to claim 5.

7. The polymer according to claim 6 further contains repeating units represented by the following formula (b1) or (b2). In the formula, R A each independently represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; X 1 is a single bond, phenylene, naphthylene, *-C(=O)-O-X 11 - or *-C(=O)-NH-X 11 -, and the phenylene or naphthylene may also be substituted by a hydroxyl group, nitro group, cyano group, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom; X 11 is a saturated alkylene group having 1 to 10 carbon atoms, phenylene or naphthylene, and the saturated alkylene group may also contain a hydroxyl group, ether bond, ester bond or lactone ring; X 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-; * represents an atomic bond between the carbon atom of the main chain. R 11 is a halogen atom, a cyano group, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon carbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon carbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom; AL 1 and AL 2 each independently represents an acid-labile group; a is an integer from 0 to 4.

8. The polymer according to claim 6 further contains repeating units represented by the following formula (b3). In the formula, 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. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; X 3 is a single bond, *-C(=O)-O- or *-C(=O)-NH-; * represents an atomic bond between the carbon atom of the main chain; R 12 and R 13 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom; further, R 12 and R 13 may also be bonded to each other and together with the carbon atoms to which they are bonded form a ring; R 14 is a halogen atom, a hydroxyl group, a cyano group, a nitro group, a C1-C20 hydrocarbon group which may contain a heteroatom, a C1-C20 hydrocarbon oxy group which may contain a heteroatom, a C2-C20 hydrocarbon oxycarbonyl group which may contain a heteroatom, a C1-C20 hydrocarbon thio group or -N(R 14A )(R 14B ); R 14A and R 14B are each independently a hydrogen atom or a C1-C6 hydrocarbon group; when b2 is 2 or more, a plurality of R 14 may also be bonded to each other and together with the carbon atoms of the aromatic ring to which they are bonded form a ring; X 4 a single bond, an aliphatic alkylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining them; X 5 and X 6 each independently represents an oxygen atom or a sulfur atom; provided that X 4 and X 6 are bonded to adjacent carbon atoms of the aromatic ring.

9. The polymer according to claim 6 further contains repeating units represented by the following formula (c1). In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; Y 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-; * represents the atomic bond between the carbon atom of the main chain; R 21 is a halogen atom, nitro group, cyano group, carboxyl group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon carbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon carbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom; c is an integer from 1 to 4; d is an integer from 0 to 3; provided that 1 ≤ c + d ≤ 5.

10. The polymer according to claim 6 further contains repeating units represented by the following formula (d1). In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; Z 1 is a single bond, phenylene, naphthylene, *-C(=O)-O-Z 11 - or *-C(=O)-NH-Z 11 -, and the phenylene or naphthylene may also be substituted with a hydroxyl group, nitro group, cyano group, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom; * represents an atomic bond between the carbon atom of the main chain and; Z 11 is a saturated alkylene group having 1 to 10 carbon atoms, phenylene or naphthylene, and the saturated alkylene group may also contain a hydroxyl group, ether bond, ester bond or lactone ring; R 31 is a hydrogen atom, or a group having 1 to 20 carbon atoms containing at least one or more structures selected from hydroxyl groups other than phenolic hydroxyl groups, cyano groups, carbonyl groups, carboxyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, and carboxylic anhydrides (-C(=O)-O-C(=O)-).

11. A chemically amplified resist composition contains (A) a base polymer containing the polymer according to claim 6.

12. The chemically amplified resist composition according to claim 11 further contains (B) an organic solvent.

13. The chemically amplified resist composition according to claim 11 further contains (C) a quencher.

14. The chemically amplified resist composition according to claim 11 further contains (D) an acid generator.

15. The chemically amplified resist composition according to claim 11 further contains (E) a surfactant.

16. The chemically amplified resist composition according to claim 11 further contains (F) a dissolution inhibitor.

17. A method for forming a pattern, comprising the following steps: forming a resist film on a substrate using the chemically amplified resist composition according to claim 11; exposing the resist film to high-energy rays; and developing the exposed resist film using a developer.

18. The pattern forming method according to claim 17, wherein, The high-energy rays are an ArF excimer laser having a wavelength of 193 nm, a KrF excimer laser having a wavelength of 248 nm, an electron beam, or extreme ultraviolet rays having a wavelength of 3 to 15 nm.

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