Onium salt monomers, polymers, chemically amplified resist compositions, and pattern forming methods

Abstract

The present invention relates to onium salt type monomers, polymers, chemically amplified resist compositions, and pattern forming methods. The present invention provides onium salt type monomers, polymers containing repeating units derived from the onium salt type monomers, chemically amplified resist compositions containing the polymers, and pattern forming methods using the chemically amplified resist compositions, which give chemically amplified resist compositions excellent in solubility to organic solvents, high sensitivity, and high contrast in optical lithography using high energy rays, excellent in lithography performance, strong in resistance to pattern collapse in fine pattern formation, and excellent in etching resistance. The present invention is an onium salt type monomer characterized by an onium salt type monomer represented by the following general formula (a). (a)

Description

Technical Field

[0001] This invention relates to onium salt type monomers, polymers, chemically amplified resist compositions, and methods for patterning. Background Technology

[0002] With the increasing integration and speed of LSI (Light Detection and Ranging) technology, the miniaturization of patterned surfaces is progressing rapidly. The expansion of the flash memory market and the increase in memory capacity are driving this miniaturization. At the forefront of miniaturization technology, mass production of 65nm node devices using ArF lithography is underway, and preparations are underway for mass production of next-generation 45nm node devices using ArF immersion lithography. For next-generation 32nm node devices, there are ongoing discussions on immersion lithography using ultra-high nanometer lenses (NA) combining liquids with higher refractive indices than water and high-refractive-index lenses, high-refractive-index resist films, extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm, and double exposure (double patterning lithography) using ArF lithography.

[0003] As miniaturization progresses, the refractive limit of light is approached, resulting in a decrease in light contrast. This decrease in light contrast leads to a reduction in the resolution or focal margin of hole or trench patterns produced in positive resist films.

[0004] As patterns become more miniaturized, the edge roughness (LWR) of the line pattern and the dimensional uniformity (CDU) of the hole pattern are considered problems. Some have pointed to the effects of uneven distribution or aggregation of the base polymer or acid generator, or the influence of acid diffusion. Furthermore, with the thinning of the resist film, there is a tendency for the LWR to increase, and the deterioration of LWR caused by thinning along with the progress of miniaturization has become a significant problem.

[0005] In EUV lithography resist compositions, it is necessary to simultaneously achieve high sensitivity, high resolution, and low light-to-weight ratio (LWR). Shortening the acid diffusion distance results in a lower LWR and reduced sensitivity. For example, lowering the post-exposure baking (PEB) temperature reduces LWR but lowers sensitivity. Increasing the amount of quencher also reduces LWR and lowers sensitivity. Therefore, it is necessary to break the trade-off between sensitivity and LWR.

[0006] To suppress acid diffusion, a resist compound containing repeating units from onium salts of sulfonic acids with polymerizable unsaturated bonds has been proposed (Patent Document 1). Such a so-called polymer-bonded acid generator, because it generates polymeric sulfonic acid upon exposure, exhibits a very short acid diffusion distance. Furthermore, sensitivity can be improved by increasing the ratio of the acid generator. In additive acid generators, increasing the amount added also increases sensitivity, and in this case, the acid diffusion distance also increases. Because acid diffuses unevenly, increased acid diffusion degrades the light-to-weight ratio (LWR) or chromatic diffusivity (CDU). In terms of the balance between sensitivity, LWR, and CDU, polymeric acid generators can be said to have high performance.

[0007] Because iodine atoms have very high absorption at a wavelength of 13.5 nm in EUV, the effect of generating secondary electrons from iodine atoms during exposure has been confirmed, making it a promising candidate for EUV lithography. Patent Document 2 describes a photoacid generator in which iodine atoms are anion-introduced, and Patent Document 3 describes a photoacid generator containing polymerizable groups in which iodine atoms are anion-introduced. This has led to improvements in lithography performance, but the trade-off between solvent solubility caused by the introduction of iodine atoms becomes problematic. Specifically, issues such as reduced solvent solubility leading to a limitation on soluble solvents and consequently reduced monomer handling performance, as well as defects caused by residual monomers in the polymer after polymerization, can be cited.

[0008] Existing technical documents

[0009] Patent documents

[0010] [Patent Document 1] Japanese Patent No. 4425776

[0011] [Patent Document 2] Japanese Patent No. 6720926

[0012] [Patent Document 3] Japanese Patent No. 6973274 Summary of the Invention

[0013] [The problem that the invention aims to solve]

[0014] The goal is to develop resist compositions that utilize acid as a catalyst, achieving higher sensitivity, improved line leaching resistance (LWR), and enhanced cavity density (CDU) of holes, while also exhibiting excellent etch resistance after patterning. Furthermore, the development of monomers or polymers with wide process margins in manufacturing and excellent solvent solubility is also desired.

[0015] The present invention was made in view of the above circumstances, and its purpose is to provide a chemically amplified resist composition that provides excellent solubility in organic solvents, high sensitivity, high contrast, and excellent photolithography performance, as well as strong resistance to pattern collapse and excellent etching resistance in the formation of fine patterns, for use in optical lithography using high-energy rays. The invention includes an onium salt monomer of a polymer, a polymer containing repeating units from the onium salt monomer, a chemically amplified resist composition containing the polymer, and a pattern formation method using the chemically amplified resist composition.

[0016] [Methods for solving the problem]

[0017] To address the aforementioned issues, the present invention provides an onium salt type monomer, which is an onium salt type monomer represented by the following general formula (a).

[0018] [Chemistry 1]

[0019] (a)

[0020] (In the formula, R1 and R4 are each independently a halogen atom, or may contain heteroatoms of a hydrocarbon group with 1 to 20 carbon atoms; R2 is represented by the following general formula (a-1); R3 is represented by the following general formula (a-2). n1 and n2 are each independently 0 or 1; n3 is an integer from 0 to 3; n4, n5, and n6 are each independently an integer from 0 to 4; 1 ≤ n4 + n5 ≤ 4 and 1 ≤ n4 + n5 + n6 ≤ 4. L1 is a single bond, ether bond, ester bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond. n7 is an integer from 0 to 4; Q...) 1 and Q 2 Each is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Q 3 and Q 4 Each is independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Z + It is a iumonium cation.

[0021] [Chemistry 2]

[0022]

[0023] (In the formula, R5 is a halogen atom excluding iodine atoms, or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms; n8 is 0 or 1; n9 is an integer from 0 to 4; and n10 is an integer from 1 to 5, satisfying the relationship 1≤n9+n10≤5.)

[0024] [Chemistry 3]

[0025]

[0026] (where AL) 1 (This is an acid-labile group.)

[0027] Such onium salt monomers can be used in the production of polymers for chemically amplified resist compositions that exhibit excellent solubility in organic solvents, high sensitivity, high contrast, and excellent lithographic performance, while also being resistant to pattern collapse during the formation of fine patterns and possessing excellent etching resistance, in optical lithography using high-energy rays.

[0028] Furthermore, the present invention provides that the above-mentioned onium salt type monomer is preferably represented by the following general formula (a1).

[0029] [Chemistry 4]

[0030] (a1)

[0031] (where n3~n7, R1~R4, L1, Q) 1 Q 2 and Z + Same as above.

[0032] For such onium salt type monomers, it is better to consider the availability of raw materials and the ease of introducing substituents.

[0033] Furthermore, the present invention is the aforementioned Z + It is preferable to use a sulfonium cation represented by the following general formula (cation-1) or a monazine cation represented by the following general formula (cation-2).

[0034] [Chemistry 5]

[0035]

[0036] (where R is in the formula) ct1 ~R ct5 Each group consists of a halogen atom or a hydrocarbon group with 1 to 30 carbon atoms, and may also contain heteroatoms. Furthermore, R... ct1 and R ct2 They can also bond with each other to form rings with the sulfur atoms they are bonded to.

[0037] The onium salt type monomers of the present invention preferably have such cations.

[0038] Furthermore, the present invention provides a polymer comprising repeating units derived from the onium salt type monomers described above.

[0039] Such polymers are used in chemically amplified resist compositions that exhibit excellent solubility in organic solvents, high sensitivity, high contrast, and excellent lithography performance, while also demonstrating strong resistance to pattern collapse during the formation of fine patterns and excellent etching resistance, in optical lithography using high-energy rays.

[0040] Furthermore, the present invention provides that the polymer described above preferably also includes repeating units represented by the following general formula (b1) or (b2).

[0041] [Chemistry 6]

[0042]

[0043] (where R is in the formula) A Each can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0044] X 1 Single bond, phenylene, naphthylene, *-C(=O)-OX 11 -、or *-C(=O)-NH-X 11 - The aforementioned phenylene and naphthylene groups can also be substituted by alkoxy or halogen atoms with 1 to 10 carbon atoms, which may also contain fluorine atoms. X 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms. The above-mentioned saturated hydrocarbon group may also contain hydroxyl groups, ether bonds, ester bonds, or lactone rings.

[0045] X 2 It is a single bond, *-C(=O)-O-, or *-C(=O)-NH-.

[0046] * indicates an atomic bond with a carbon atom in the main chain.

[0047] AL 2 and AL 3 Each is an acid-labile group.

[0048] R 11 It may contain halogen atoms, cyano, hydroxyl, nitro, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl oxy group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms.

[0049] (where a is an integer between 0 and 4.)

[0050] Furthermore, the present invention may also include repeating units represented by the following general formula (c1) in the polymer described above.

[0051] [Chemistry 7]

[0052]

[0053] (where R is in the formula) A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0054] Y 1It can be a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * indicates an atomic bond with a carbon atom in the main chain.

[0055] R 21 It can be a halogen atom, nitro group, cyano group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl oxy group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms.

[0056] c is an integer from 1 to 4. d is an integer from 0 to 3. However, 1 ≤ c + d ≤ 5.

[0057] Furthermore, the present invention may also include repeating units represented by the following general formula (d1) in the polymer described above.

[0058] [Chemistry 8]

[0059]

[0060] (where R is in the formula) A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0061] Z 1 Single bond, phenylene, naphthylene, *-C(=O)-OZ 11 -、or *-C(=O)-NH-Z 11 - The aforementioned phenylene and naphthylene groups can also be substituted by alkoxy or halogen atoms with 1 to 10 carbon atoms, which may also contain fluorine atoms. * indicates an atomic bond with a carbon atom in the main chain. Z 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms. The above-mentioned saturated hydrocarbon group may also contain hydroxyl groups, ether bonds, ester bonds, or lactone rings.

[0062] R 31 It is a hydrogen atom, or a group containing at least one of the following structures: hydroxyl group (other than phenolic hydroxyl group), cyano group, carbonyl group, carboxyl group, ether bond, ester bond, sulfonate bond, carbonate bond, lactone ring, sulopentalide ring, and carboxylic anhydride (-C(=O)-OC(=O)-).

[0063] The present invention preferably provides that the polymer has such repeating units.

[0064] Furthermore, the present invention provides a chemically amplified resist composition, which is a chemically amplified resist composition containing (A) a base polymer comprising the polymer described above.

[0065] Such a chemically amplified resist composition becomes a chemically amplified resist composition that exhibits excellent solubility in organic solvents, high sensitivity, high contrast, and excellent photolithography performance, while also showing strong resistance to pattern collapse during the formation of fine patterns and excellent etching resistance in optical lithography using high-energy rays.

[0066] At this time, the chemically amplified resist composition mentioned above should preferably also contain one or more of the following: (B) organic solvent, (C) quencher, (D) acid generator, (E) surfactant, and (F) dissolution inhibitor.

[0067] The chemically amplified resist composition of the present invention may contain such additives.

[0068] Furthermore, the present invention provides a pattern forming method comprising the following steps: forming a resist film on a substrate using the chemically amplified resist composition described above; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developing solution.

[0069] For such a pattern forming method, a pattern forming method can be provided that uses a chemically amplified resist composition that has excellent solubility in organic solvents, high sensitivity, high contrast, excellent photolithography performance, strong resistance to pattern collapse in the formation of fine patterns, and excellent etching resistance in optical lithography using high-energy rays.

[0070] At this time, the appropriate high-energy rays to use are ArF excimer lasers with a wavelength of 193nm, KrF excimer lasers with a wavelength of 248nm, electron beams, or extreme ultraviolet rays with a wavelength of 3~15nm.

[0071] The pattern forming method of the present invention is preferably made using such high-energy rays.

[0072] [The effects of the invention]

[0073] As described above, chemically amplified resist compositions containing polymers comprising repeating units of onium salt type monomers represented by the above general formula (a) of the present invention, while possessing good organic solvent solubility through the action of substituents bonded to ether linkers via a mesostyrene structure, can appropriately select substituents. For example, not only can the introduction of iodine atoms enhance the resist's EUV sensitivity, improve LWR and CDU, but by incorporating leaving groups into the substituents, it is expected to reduce residue after development, thus becoming chemically amplified resist compositions with fewer defects after development. The monomers of the present invention are suitable as monomers for polymers contained in such chemically amplified resist compositions. Furthermore, by constructing the main skeleton of the monomer with aromatic rings, good etching resistance is imparted, making it suitable for fine pattern formation. In particular, it can be used as a chemically amplified resist composition in optical lithography using high-energy rays such as KrF excimer lasers, ArF excimer lasers, electron beams (EB), and EUV. It has excellent solubility in organic solvents, high sensitivity, high contrast, and excellent lithography performance in terms of exposure margin (EL), LWR, CDU, and depth of focus (DOF). At the same time, it also has strong resistance to pattern collapse and excellent etching resistance in the formation of fine patterns. Detailed Implementation

[0074] As mentioned above, there is a search for chemically amplified resist compositions that can provide excellent solubility in organic solvents, high sensitivity, high contrast, excellent lithographic performance, strong resistance to pattern collapse in micro-pattern formation, and excellent etching resistance in optical lithography using high-energy rays. These include onium salt monomers of polymers, polymers containing repeating units from the onium salt monomers, chemically amplified resist compositions containing the polymers, and pattern formation methods using the chemically amplified resist compositions.

[0075] As a result of repeated and in-depth exploration in order to achieve the above-mentioned objectives, the inventors of this application discovered that by using a polymer containing repeating units from onium salts as polymer-bonded acid generators, wherein the onium salts contain fluorosulfonic acid anions with a styrene structure as polymerizable groups and an aromatic ring structure with iodine atoms as substituents or an aromatic ring structure combined with acid leaving groups, it is possible to obtain a chemically amplified resist composition with excellent solubility in organic solvents, high sensitivity, improved LWR and CDU, high contrast, high resolution, excellent etching resistance, and reduced defects after development, thus completing the present invention.

[0076] That is, the present invention is an onium salt type monomer, which is an onium salt type monomer represented by the following general formula (a).

[0077] [Chemistry 9]

[0078] (a)

[0079] (In the formula, R1 and R4 are each independently a halogen atom, or may contain heteroatoms of a hydrocarbon group with 1 to 20 carbon atoms; R2 is represented by the following general formula (a-1); R3 is represented by the following general formula (a-2). n1 and n2 are each independently 0 or 1; n3 is an integer from 0 to 3; n4, n5, and n6 are each independently an integer from 0 to 4; 1 ≤ n4 + n5 ≤ 4 and 1 ≤ n4 + n5 + n6 ≤ 4. L1 is a single bond, ether bond, ester bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond. n7 is an integer from 0 to 4; Q...) 1 and Q 2 Each is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Q 3 and Q 4 Each is independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Z + It is a iumonium cation.

[0080] [Chemistry 10]

[0081]

[0082] (In the formula, R5 is a halogen atom excluding iodine atoms, or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms; n8 is 0 or 1; n9 is an integer from 0 to 4; and n10 is an integer from 1 to 5, satisfying the relationship 1≤n9+n10≤5.)

[0083] [Chemistry 11]

[0084]

[0085] (where AL) 1 (This is an acid-labile group.)

[0086] The present invention will now be described in detail, but the present invention is not limited thereto.

[0087] [Onium salt type monomer]

[0088] The onium salt type monomer of the present invention is represented by the following general formula (a).

[0089] [Chemistry 12]

[0090] (a)

[0091] (In the formula, R1 and R4 are each independently a halogen atom, or may contain heteroatoms of a hydrocarbon group with 1 to 20 carbon atoms; R2 is represented by the following general formula (a-1); R3 is represented by the following general formula (a-2). n1 and n2 are each independently 0 or 1; n3 is an integer from 0 to 3; n4, n5, and n6 are each independently an integer from 0 to 4; 1 ≤ n4 + n5 ≤ 4 and 1 ≤ n4 + n5 + n6 ≤ 4. L1 is a single bond, ether bond, ester bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond. n7 is an integer from 0 to 4; Q...) 1 and Q 2 Each is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Q 3 and Q 4 Each is independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Z + It is a iumonium cation.

[0092] [Chemistry 13]

[0093]

[0094] (In the formula, R5 is a halogen atom excluding iodine atoms, or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms; n8 is 0 or 1; n9 is an integer from 0 to 4; and n10 is an integer from 1 to 5, satisfying the relationship 1≤n9+n10≤5.)

[0095] [Chemistry 14]

[0096]

[0097] (where AL) 1 (This is an acid-labile group.)

[0098] In the above general formula (a), n1 and n2 are 0 or 1. Considering the availability of raw materials, it is preferable that n1 is 0. n3 is an integer from 0 to 3, depending on the appropriate number of substituents. For example, in the case of introducing iodine atoms, the more iodine atoms in the anionic structure, the better the absorption of EUV, but the less solvent solubility there is a concern about precipitation in the resist composition. It is advisable to control n3 within an appropriate range, preferably 0 ≤ n3 ≤ 2. n4, n5, and n6 are integers from 0 to 4, satisfying the relationship 1 ≤ n4 + n5 ≤ 4 and 1 ≤ n4 + n5 + n6 ≤ 4. In this case, at least either n4 or n5 needs to be 1 or higher. The substituents can be selected according to the required performance. Considering the availability of raw materials, it is preferable that 1 ≤ n4 + n5 ≤ 3 and 1 ≤ n4 + n5 + n6 ≤ 3, and it is even better if the relationship 1 ≤ n4, 1 ≤ n5, and 2 ≤ n4 + n5 + n6 ≤ 3 is satisfied. Both the acid-leaching group and the substituent with iodine substituent have one or more aspects of both improved sensitivity and defect improvement, and are therefore preferred.

[0099] In the above general formula (a), the substituent R2 or R3 is preferably bonded to the adjacent position of the L1 bonded carbon atom of the anion. This positional relationship mitigates the aggregation of molecules through steric hindrance, thus suppressing solvent solubility degradation. Furthermore, by introducing a styrene structure via a meso-ether bond, heat resistance or etching resistance can be improved. Moreover, by appropriately selecting the substituents R2 or R3, the monomer can be adjusted to meet requirements such as improved EUV sensitivity or improved solubility in the developer after photolithography.

[0100] In the above general formula (a), R1 and R4 are halogen atoms, or hydrocarbon groups with 1 to 20 carbon atoms that may contain heteroatoms. The halogen atoms mentioned above are fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. The hydrocarbon groups mentioned above may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkyl groups with 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecanyl, octadecyl, nonadecanyl, and eicosyl; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norcamphenyl, and adamantyl; alkenyl groups with 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclounsaturated alkyl groups with 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups with 6 to 20 carbon atoms, such as phenyl and naphthyl; aralkyl groups with 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combinations thereof. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon groups can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms. Similarly, a portion of the -CH2- group in the aforementioned hydrocarbon groups can be replaced by groups containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, groups may contain hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone, sulfonate, carboxylic anhydride (-C(=O)-OC(=O)-), or haloalkyl groups. When n3 is 2 or 3, each R1 can be the same or different. When n6 is 2, 3, or 4, each R4 can be the same or different. Considering the improvement of solvent solubility, when R1 and R4 are halogen atoms, fluorine or iodine atoms are preferable; for improved EUV sensitivity, iodine atoms are more preferable. When R1 and R4 are hydrocarbon groups with 1 to 20 carbon atoms that may also contain heteroatoms, alkyloxy groups are preferred, and methoxy or ethoxy groups are even more preferred.

[0101] Furthermore, when n3 or n6 is an integer greater than 2, multiple R1 or R4 rings can bond together to form a ring with the carbon atoms of the aromatic rings they are bonded to. Specific examples of rings formed in this way include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, and adamantane rings. In addition, some or all of the hydrogen atoms in the above rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms, and some of the -CH2- group in the above rings can also be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, the rings may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulopentalide rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0102] In the above general formula (a), L1 is a single bond, ether bond, ester bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond, preferably a single bond, ether bond, ester bond, or sulfonate bond, and more preferably a single bond, ether bond, or ester bond.

[0103] In the above general formula (a), n7 is an integer from 0 to 4, preferably from 0 to 3, and even more preferably from 0 to 2.

[0104] In the above general formula (a), Q 1 and Q 2 Each of the following is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Trifluoromethyl is preferred as the fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0105] In the above general formula (a), Q 3 and Q 4 Each is independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. As a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, trifluoromethyl is preferred. As Q 3 and Q 4 It is more suitable to have fluorine atoms.

[0106] In the above general formula (a), as -[C(Q 1 (Q) 2 )] n7 -C(Q 3 (Q) 4 )-SO3 - Specific examples of the partial structures shown are preferably as shown below, but are not limited to these. Furthermore, in the following formula, * denotes an atomic bond with L1.

[0107] [Chemistry 15]

[0108]

[0109] R2 represents the substituent in the above general formula (a-1), n8 is 0 or 1. Considering the ease of obtaining the raw materials, n8=0 is preferable. n9 is an integer from 0 to 4, and n10 is an integer from 1 to 5. Considering the relationship 1≤n9+n10≤5, and considering the ease of introducing substituents on the aromatic ring, 0≤n9≤3 is preferable. Considering the improvement of EUV sensitivity, the substituent with more iodine atoms is preferable. Due to the trade-off with solvent solubility, 1≤n10≤3 is preferable, and the relationship 1≤n9+n10≤3 is preferable.

[0110] In the above general formula (a-1), R5 is a halogen atom excluding iodine, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms. Specific examples include substituents identical to those of R1 and R4 mentioned above, excluding iodine atoms as far as halogen atoms are concerned. Furthermore, when n9 is an integer of 2 or more, they may also bond to each other and form a ring together with the carbon atoms of the aromatic rings to which they are bonded. Specific examples of the rings formed in this case are those identical to those of the above-mentioned R1 and R4 bonding to each other and forming a ring together with the carbon atoms of the aromatic rings to which they are bonded.

[0111] Specifically, R2 can be exemplified by the following structures. Among these, those with multiple iodine substituents on the aromatic ring are preferable.

[0112] [Chemistry 16]

[0113]

[0114] R3 is the substituent represented by the above general formula (a-2), where AL1 is an acid-labile group. Specific examples of the above-mentioned acid-labile groups may be found in Japanese Patent Application Publication No. 2013-080033 and Japanese Patent Application Publication No. 2013-083821, but are not limited to these.

[0115] Specific examples of the aforementioned unstable acid groups can be represented by the following general formulas (AL-1) to (AL-3).

[0116] [Chemistry 17]

[0117]

[0118] (In the formula, * represents an atomic bond.)

[0119] In the above general formulas (AL-1) and (AL-2), R L1 and R L2 Each hydrocarbon group is independently composed of 1 to 40 carbon atoms, and may also contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, and iodine atoms. These hydrocarbon groups can be linear, branched, or cyclic. Preferably, they are composed of 1 to 20 carbon atoms.

[0120] In the above general formula (AL-1), a is an integer from 0 to 10, preferably an integer from 1 to 5.

[0121] In the above general formula (AL-2), R L3 and R L4 Each group is independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and may also contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, and iodine atoms. These hydrocarbon groups can be linear, branched, or cyclic. Furthermore, R... L2 R L3 and R L4 Any two of them can bond to each other to form a ring with 3 to 20 carbon atoms, or carbon and oxygen atoms. The ring with 4 to 16 carbon atoms is preferred, and alicyclic rings are particularly preferred.

[0122] In the above general formula (AL-3), R L5 R L6 and R L7 Each group is an independent hydrocarbon group with 1 to 20 carbon atoms, and may also contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, and iodine atoms. These hydrocarbon groups can be linear, branched, or cyclic. Furthermore, R... L5 R L6 and R L7 Any two of them can bond to each other to form a ring with 3 to 20 carbon atoms. The ring with 4 to 16 carbon atoms is preferred, and alicyclic rings are especially preferred.

[0123] Of the above, considering the ease of manufacturing, the structure represented by the general formula (AL-3) is preferred. Specifically, the following structures can be exemplified. Among these, it is preferable that R3 constitutes a tert-butoxy, tert-amyloxy, or other tert-alkyl ether structures.

[0124] [Chemistry 18]

[0125]

[0126] [Chemistry 19]

[0127]

[0128] [Chemistry 20]

[0129]

[0130] The onium salt type monomer represented by the above general formula (a) is preferably represented by the following general formula (a1).

[0131] [Chemistry 21]

[0132] (a1)

[0133] (where n3~n7, R1~R4, L1, Q) 1 Q 2 and Z + Same as above.

[0134] As with the general formula (a1) above, the onium salt type monomer of the present invention is superior in that all aromatic rings with polymerizable groups, which are linked by ether, and all aromatic rings with substituents R2, R3, and R4 are benzene rings, considering the availability of raw materials and the ease of introducing substituents. By appropriately selecting the combination of R2 and R3, it is expected that the defect suppression effect, such as improved EUV sensitivity or reduction of scum that may be a problem during photolithography, can be achieved.

[0135] Specific examples of the anions of onium salt type monomers represented by the above general formula (a1) can be listed below, but are not limited to these. Furthermore, in the following formula, R2, R3, Q... 1 Q 2 Similar to n7, the bonding positions of various substituents on the aromatic ring can also be interchanged.

[0136] [Chemistry 22]

[0137]

[0138] [Chemistry 23]

[0139]

[0140] [Chemistry 24]

[0141]

[0142] [Chemistry 25]

[0143]

[0144] [Chemistry 26]

[0145]

[0146] [Chemistry 27]

[0147]

[0148] [Chemistry 28]

[0149]

[0150] [Chemistry 29]

[0151]

[0152] [Chemistry 30]

[0153]

[0154] [Chemistry 31]

[0155]

[0156] [Chemistry 32]

[0157]

[0158] [Chemistry 33]

[0159]

[0160] [Chemistry 34]

[0161]

[0162] [Chemistry 35]

[0163]

[0164] [Chemistry 36]

[0165]

[0166] [Chemistry 37]

[0167]

[0168] [Chemistry 38]

[0169]

[0170] [Chemistry 39]

[0171]

[0172] [Chemistry 40]

[0173]

[0174] [Chemistry 41]

[0175]

[0176] [Chemistry 42]

[0177]

[0178] [Chemistry 43]

[0179]

[0180] [Chemistry 44]

[0181]

[0182] [Chemistry 45]

[0183]

[0184] In the above structural formula, it is preferable to use L1-[C(Q 1 (Q) 2 )] n7 -CF2-SO3 - The structure shown below represents a partial structure. Specifically, L1 is an ester bond, n7=1, Q 1 Or Q 2 The combination of hydrogen atoms, fluorine atoms, or trifluoromethyl groups is preferred. Acid-1a or Acid-2a, as in the specific examples below, are even more desirable.

[0185] [Chemistry 46]

[0186]

[0187] In the above general formula (a), Z + It is a iumonium cation. The above Z + It is preferable to use a sulfonium cation represented by the following general formula (cation-1) or a monazine cation represented by the following general formula (cation-2).

[0188] [Chemistry 47]

[0189]

[0190] (where R is in the formula) ct1 ~R ct5 Each group consists of a halogen atom or a hydrocarbon group with 1 to 30 carbon atoms, and may also contain heteroatoms. Furthermore, R... ct1 and R ct2 They can also bond with each other to form rings with the sulfur atoms they are bonded to.

[0191] In the above general formulas (cation-1) and (cation-2), R ct1 ~R ct5 Each is an independent hydrocarbon group consisting of halogen atoms or may contain heteroatoms, and has 1 to 30 carbon atoms.

[0192] As R ct1 ~R ct5 Specific examples of halogen atoms can be listed, such as fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0193] R ct1 ~R ct5The hydrocarbon group represented can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include alkyl groups with 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; cyclic saturated hydrocarbon groups with 3 to 30 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornel, and adamantyl; alkenyl groups with 2 to 30 carbon atoms such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups with 3 to 30 carbon atoms such as cyclohexenyl; aryl groups with 6 to 30 carbon atoms such as phenyl, naphthyl, and thiophene; aralkyl groups with 7 to 30 carbon atoms such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these, preferably aryl groups. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. A portion of the -CH2- group in the aforementioned hydrocarbon group can also be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulopentatone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0194] In addition, R ct1 and R ct2 They can also bond with each other to form a ring together with the sulfur atoms they are bonded to. In this case, specific examples of the above-mentioned ring structures can be listed, such as those represented by the following formulas.

[0195] [Chemistry 48]

[0196]

[0197] (In the formula, the dashed line represents the intersection with R) ct3 (Atomic bonds.)

[0198] Specific examples of sulfonium cations represented by the above general formula (cation-1) can be listed below, but are not limited to these.

[0199] [Chemistry 49]

[0200]

[0201] [Transformation 50]

[0202]

[0203] [Chemistry 51]

[0204]

[0205] [Chemistry 52]

[0206]

[0207] [Chemistry 53]

[0208]

[0209] [Chemistry 54]

[0210]

[0211] [Chemistry 55]

[0212]

[0213] [Chemistry 56]

[0214]

[0215] [Chemistry 57]

[0216]

[0217] [Chem.58]

[0218]

[0219] [Chemistry 59]

[0220]

[0221] [Transformation 60]

[0222]

[0223] [Chemistry 61]

[0224]

[0225] [Chemistry 62]

[0226]

[0227] [Chemistry 63]

[0228]

[0229] [Chemistry 64]

[0230]

[0231] [Chemistry 65]

[0232]

[0233] [Chemistry 66]

[0234]

[0235] [Chemistry 67]

[0236]

[0237] [Chemistry 68]

[0238]

[0239] [Chemistry 69]

[0240]

[0241] [Chemistry 70]

[0242]

[0243] [Chemistry 71]

[0244]

[0245] [Chemistry 72]

[0246]

[0247] [Chemistry 73]

[0248]

[0249] [Chemistry 74]

[0250]

[0251] [Chemistry 75]

[0252]

[0253] Specific examples of citric cations represented by the above general formula (cation-2) can be listed below, but are not limited to these.

[0254] [Chemistry 76]

[0255]

[0256] [Chemistry 77]

[0257]

[0258] As a specific example of the onium salt type monomer represented by the above general formula (a), any combination of the above anions and cations can be listed.

[0259] The onium salt type monomer represented by the above general formula (a) can be synthesized, for example, by the same method as that described in Japanese Patent No. 5201363 for a sulfonium salt having a polymerizable anion, but is not limited to that method.

[0260] [polymer]

[0261] The polymer of the present invention comprises repeating units (hereinafter also referred to as repeating unit a) derived from the onium salt type monomer represented by the above general formula (a).

[0262] The polymer of the present invention is a polymer-bonded photoacid generator that functions as both a photoacid generator and a base polymer in a chemically amplified resist composition. Structurally, the polymer of the present invention includes repeating units derived from the onium salt monomer of the present invention. These repeating units have an onium salt structure containing a benzene or naphthalene structure directly bonded to the main chain and an aromatic ring structure substituted with an acid-leaching group or an iodine atom. Iodine atoms exhibit high absorption at EUV wavelengths of 13.5 nm, thus generating secondary electrons during exposure. These secondary electrons move towards the photoacid generator, promoting decomposition and thereby increasing sensitivity. The polymerizable groups composed of styrene are more rigid than those of methacrylates, increasing the polymer's glass transition temperature (Tg). It is believed that through the interaction of aromatic rings within or between the base polymers (π-π stacking effect), the base polymers are regularly arranged, exhibiting resistance to pattern collapse even during the formation of fine patterns in the developer. Furthermore, in the etching step after the formation of fine patterns, the aromatic rings directly bonded to the main chain exhibit excellent etching resistance. It is preferable to introduce at least one of the following as adjacent substituents into the aromatic ring: an acid-leaning group or an iodine atom-substituted aromatic ring, or a substituent with an anionic site and a polymerizable functional group. The adjacent substituents are expected to suppress the rotation of the bond axis through steric hindrance on the aromatic ring. Therefore, it is excellent for suppressing excessive acid diffusion that generates acid, resulting in LWR with line patterns or CDU with hole patterns, and can form patterns with strong resistance to pattern collapse. Therefore, it is particularly suitable as a material for chemically amplified positive resist compositions. Furthermore, acid-leaning groups can be introduced onto the aromatic rings with anionic and styrene-structured linking groups. The acid-leaning groups introduced onto the aromatic rings cause a detachment reaction during exposure to generate alkali-soluble groups. These alkali-soluble groups are expected to improve the solubility in the developer, specifically reducing defects by decreasing the amount of alkali-insoluble residue after development.

[0263] The polymer may also contain repeating units represented by the following general formula (b1) (hereinafter also referred to as repeating unit b1.) or repeating units represented by the following general formula (b2) (hereinafter also referred to as repeating unit b2.).

[0264] [Chemistry 78]

[0265]

[0266] (where R is in the formula) A Each can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0267] X 1 Single bond, phenylene, naphthylene, *-C(=O)-OX 11 -、or *-C(=O)-NH-X 11 - The aforementioned phenylene and naphthylene groups can also be substituted by alkoxy or halogen atoms with 1 to 10 carbon atoms, which may also contain fluorine atoms. X 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms. The above-mentioned saturated hydrocarbon group may also contain hydroxyl groups, ether bonds, ester bonds, or lactone rings.

[0268] X 2 It is a single bond, *-C(=O)-O-, or *-C(=O)-NH-.

[0269] * indicates an atomic bond with a carbon atom in the main chain.

[0270] AL 2 and AL 3 Each is an acid-labile group.

[0271] R 11 It may contain halogen atoms, cyano, hydroxyl, nitro, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl oxy group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms.

[0272] (where a is an integer between 0 and 4.)

[0273] In the above general formulas (b1) and (b2), R A Each can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0274] In the above general formula (b1), X 1 Single bond, phenylene, naphthylene, *-C(=O)-OX 11 -、or *-C(=O)-NH-X 11 - The aforementioned phenylene and naphthylene groups can also be substituted by alkoxy or halogen atoms with 1 to 10 carbon atoms, which may also contain fluorine atoms. X 11It is a saturated hydrocarbon group, phenylene group, or naphthylene group having 1 to 10 carbon atoms. The above-mentioned saturated hydrocarbon group may also contain hydroxyl groups, ether bonds, ester bonds, or lactone rings. * indicates an atomic bond with a carbon atom in the main chain.

[0275] In the above general formula (b2), X 2 It represents a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * indicates an atomic bond with a carbon atom in the main chain. R 11 It can be a halogen atom, cyano group, hydroxyl group, nitro group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl oxy group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms. 'a' is an integer from 0 to 4, preferably 0 or 1.

[0276] In the above general formulas (b1) and (b2), AL 2 and AL 3 Each is an acid-labile group. Specifically, it can be used with the aforementioned AL... 1 Those that are the same.

[0277] Specific examples of the repeating unit b1 can be listed below, but are not limited to these. Furthermore, in the following formula, R... A and AL 2 Same as above.

[0278] [Chemistry 79]

[0279]

[0280] [Chemistry 80]

[0281]

[0282] [Chemistry 81]

[0283]

[0284] [Chemistry 82]

[0285]

[0286] [Chemistry 83]

[0287]

[0288] [Chemistry 84]

[0289]

[0290] [Chemistry 85]

[0291]

[0292] Specific examples of the repeating unit b2 can be listed below, but are not limited to these. Furthermore, in the following formula, R... A and AL 3 Same as above.

[0293] [Chemistry 86]

[0294]

[0295] [Chemistry 87]

[0296]

[0297] [Chemistry 88]

[0298]

[0299] The polymer described above preferably also contains repeating units represented by the following general formula (c1) (hereinafter also referred to as repeating unit c0).

[0300] [Chemistry 89]

[0301]

[0302] (where R is in the formula) A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0303] Y 1 It can be a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * indicates an atomic bond with a carbon atom in the main chain.

[0304] R 21 It can be a halogen atom, nitro group, cyano group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl oxy group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms.

[0305] c is an integer from 1 to 4. d is an integer from 0 to 3. However, 1 ≤ c + d ≤ 5.

[0306] In the above general formula (c1), R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 It represents a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * indicates an atomic bond with a carbon atom in the main chain. R 21The radical can be a halogen atom, nitro group, cyano group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyl oxy group with 2 to 20 carbon atoms containing heteroatoms; or a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms. c is an integer from 1 to 4. d is an integer from 0 to 3. However, 1 ≤ c + d ≤ 5.

[0307] Specific examples of the repeating unit c can be listed below, but are not limited to these. Furthermore, in the following formula, R... A Same as above.

[0308] [Chemistry 90]

[0309]

[0310] [Chemistry 91]

[0311]

[0312] [Chemistry 92]

[0313]

[0314] [Chemistry 93]

[0315]

[0316] [Chemistry 94]

[0317]

[0318] The polymer described above may also contain repeating units represented by the following general formula (d1) (hereinafter also referred to as repeating units d.).

[0319] [Chemistry 95]

[0320]

[0321] (where R is in the formula) A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0322] Z 1 Single bond, phenylene, naphthylene, *-C(=O)-OZ 11 -、or *-C(=O)-NH-Z 11 - The aforementioned phenylene and naphthylene groups can also be substituted by alkoxy or halogen atoms with 1 to 10 carbon atoms, which may also contain fluorine atoms. * indicates an atomic bond with a carbon atom in the main chain. Z 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms. The above-mentioned saturated hydrocarbon group may also contain hydroxyl groups, ether bonds, ester bonds, or lactone rings.

[0323] R 31 It is a hydrogen atom, or a group having 1 to 20 carbon atoms containing at least one of the following structures: hydroxyl group (other than phenolic hydroxyl), cyano group, carbonyl group, carboxyl group, ether bond, ester bond, sulfonate bond, carbonate bond, lactone ring, sulopentalide ring, and carboxylic anhydride (-C(=O)-OC(=O)-).

[0324] In the above general formula (d1), R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 Single bond, phenylene, naphthylene, *-C(=O)-OZ 11 -、or *-C(=O)-NH-Z 11 - The aforementioned phenylene and naphthylene groups can also be substituted by alkoxy or halogen atoms with 1 to 10 carbon atoms, which may also contain fluorine atoms. * indicates an atomic bond with a carbon atom in the main chain. Z 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group having 1 to 10 carbon atoms. The above-mentioned saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or an lactone ring. R 31 It is a hydrogen atom, or a group with 1 to 20 carbon atoms containing at least one of the following structures: hydroxyl group (other than phenolic hydroxyl group), cyano group, carbonyl group, carboxyl group, ether bond, ester bond, sulfonate bond, carbonate bond, lactone ring, sulcinolone ring, and carboxylic anhydride (-C(=O)-OC(=O)-).

[0325] Specific examples of the repeating unit d can be listed below, but are not limited to these. Furthermore, in the following formula, R... A Same as above.

[0326] [Chemistry 96]

[0327]

[0328] [Chemistry 97]

[0329]

[0330] [Chem. 98]

[0331]

[0332] [Chemistry 99]

[0333]

[0334] [Chemistry 100]

[0335]

[0336] [Chemistry 101]

[0337]

[0338] [Chemistry 102]

[0339]

[0340] [Chemistry 103]

[0341]

[0342] [Chemistry 104]

[0343]

[0344] [Chemistry 105]

[0345]

[0346] [Chemistry 106]

[0347]

[0348] [Chemistry 107]

[0349]

[0350] [Chemistry 108]

[0351]

[0352] [Chemistry 109]

[0353]

[0354] [Chemical 110]

[0355]

[0356] [Chemistry 111]

[0357]

[0358] Regarding repeating units c and d, in ArF lithography, those with lactone rings are particularly suitable, while in KrF lithography, EB lithography, and EUV lithography, those with phenolic sites are suitable.

[0359] The polymers described above may also contain repeating units (hereinafter also referred to as repeating units e) having a structure in which hydroxyl groups are protected by acid-indestructible groups. As repeating unit e, there are no particular limitations as long as it has one or more hydroxyl-protected structures and the protecting groups are decomposed by acid to produce hydroxyl groups, and it is preferably represented by the following general formula (e1).

[0360] [Chemistry 112]

[0361]

[0362] In the above general formula (e1), R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 41 It can also be a hydrocarbon group with 1 to 30 carbon atoms and a (e+1) valence, which may contain heteroatoms. R 42 It is an acid-labile group. e is an integer from 1 to 4.

[0363] In the above general formula (e1), R 42 The acid-unstable group can be any group that undergoes deprotection by acid to produce a hydroxyl group. R 42 The structure is not particularly limited, but is preferably an acetal structure, a ketal structure, an alkoxy carbonyl group, or an alkoxy methyl group represented by the following general formula (e2), and is especially preferably an alkoxy methyl group represented by the following general formula (e2).

[0364] [Chemistry 113]

[0365]

[0366] (In the formula, * represents an atomic bond. R) 43 It consists of a hydrocarbon group with 1 to 15 carbon atoms.

[0367] As R 42 Specific examples of the acid-unstable group, the alkoxymethyl group represented by the above general formula (e2), and the repeating unit e can be those that are the same as those illustrated in the description of the repeating unit d disclosed in Japanese Patent Application Publication No. 2020-111564.

[0368] The polymers described above may also contain repeating units f derived from indene, benzofuran, benzothiophene, vinylnaphthalene, cromoglycan, coumarin, norbornadiene, or derivatives thereof. Specific examples of monomers giving repeating units f are shown below, but are not limited to these.

[0369] [Chemistry 114]

[0370]

[0371] The polymers described above may also contain repeating units g derived from styrene, indane, vinylpyridine, or vinylcarbazole.

[0372] In the polymer of the present invention, the content ratio of repeating units a, b1, b2, c, d, e, f, and g is preferably 0 < a ≤ 0.4, 0 < b1 ≤ 0.8, 0 ≤ b2 ≤ 0.8, 0 < c ≤ 0.6, 0 ≤ d ≤ 0.6, 0 ≤ e ≤ 0.3, 0 ≤ f ≤ 0.3, and 0 ≤ g ≤ 0.3, more preferably 0 < a ≤ 0.3, 0 < b1 ≤ 0.7, 0 ≤ b2 ≤ 0.7, 0 < c ≤ 0.5, 0 ≤ d ≤ 0.5, 0 ≤ e ≤ 0.2, 0 ≤ f ≤ 0.2, and 0 ≤ g ≤ 0.2. However, a + b1 + b2 + c + d + e + f + g ≤ 1.0.

[0373] The weight-average molecular weight (Mw) of the aforementioned polymer is preferably between 1,000 and 500,000, more preferably between 3,000 and 100,000. As long as Mw is within this range, sufficient etch resistance can be obtained, and there is no concern that the difference in dissolution rate before and after exposure could lead to a decrease in resolution. Furthermore, the Mw in this invention is a converted value determined using gel permeation chromatography (GPC) with tetrahydrofuran (THF) or N,N-dimethylformamide (DMF) as solvents, using polystyrene or polymethyl methacrylate.

[0374] Furthermore, as the molecular weight distribution (Mw / Mn) of the aforementioned polymers becomes finer following the pattern regularity, the influence of Mw / Mn tends to increase. Therefore, in order to obtain a chemically amplified resist composition suitable for fine pattern sizes, a narrow dispersion with Mw / Mn of 1.0 to 2.0 is preferable. As long as it is within the above range, and there are few polymers with lower or higher molecular weights than Mw, there is no concern about observing impurities or pattern shape deterioration on the pattern after exposure.

[0375] As a method for synthesizing the above-mentioned polymer, one example is to polymerize the monomers of the repeating units in an organic solvent by adding a free radical polymerization initiator and heating the solution.

[0376] Specific examples of organic solvents used in polymerization include toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), and γ-butyrolactone (GBL). Specific examples of free radical polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), azobisisobutyronitrile, dimethyl 2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, and lauroyl peroxide. The amount of such free radical polymerization initiators added relative to the total monomers being polymerized should preferably be 0.01 to 25 mol%. The reaction temperature should preferably be 50 to 150°C, more preferably 60 to 100°C. The reaction time should preferably be 2 to 24 hours, and from a production efficiency perspective, 2 to 12 hours is more preferable.

[0377] The aforementioned free radical polymerization initiator can be added to the monomer solution and supplied to the reactor, or a separate free radical polymerization initiator solution can be prepared and supplied to the reactor independently. Considering the possibility of polymerization and the formation of ultra-high molecular weight polymers due to free radicals generated from the free radical polymerization initiator during the waiting time, from a quality management perspective, the monomer solution and the free radical polymerization initiator solution should preferably be prepared independently and added dropwise. Acid-labile groups can be used directly introduced into the monomer, or post-polymerization protection or partial protection can be performed. Furthermore, to adjust the molecular weight, known chain transfer agents such as dodecyl mercaptan or 2-mercaptoethanol can be used. In this case, the amount of such chain transfer agent added relative to the total amount of monomers polymerized should preferably be 0.01 to 20 mol%.

[0378] Furthermore, living radical polymerization can also be used to obtain polymers with narrow dispersion. This method, known as Reversible Addition Fragmentation Chain Transfer (RAFT) polymerization, utilizes living radicals because the free radicals at the polymer ends are always in an active state. By starting polymerization with the first monomer and adding the second monomer during this consumption phase, block copolymers consisting of the first and second repeating units can be formed. When used for copolymerization, this maintains a balance of free radical concentration within the system, thus exhibiting the characteristic of forming narrow dispersion polymers even when copolymerizing multiple monomers.

[0379] Organic solvents used in RAFT polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, and dioxane. Polymer initiators include 2,2'-azobisisobutyronitrile (AIBN), azobisisobutyronitrile, dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The polymerization temperature is preferably 50–80°C. The reaction time is preferably 2–100 hours, and more preferably 5–20 hours.

[0380] For RAFT polymerization, chain transfer agents are required. Specific examples include 2-cyano-2-propylbenzothioester, 4-cyano-4-phenylcarbonthioylthiopentanoic acid, 2-cyano-2-propyldodecyl trithiocarbonate, 4-cyano-4-[(dodecylthiothiocarbonyl)hydrothio]pentanoic acid, 2-(dodecylthiocarbonthiothio)-2-methylpropionic acid, cyanomethyldodecyl thiocarbonate, cyanomethyl N-methyl-N-phenylaminoformylthioester, bis(thiobenzyl)disulfide, and bis(dodecylthiothiocarbonyl)disulfide. Among these, 2-cyano-2-propylbenzothioester is preferred. In this case, the amount of such chain transfer agent added, considering the viewpoint of ensuring sufficient reaction of the living polymerization, should preferably be 0.01 to 20 mol relative to the total monomers being polymerized.

[0381] Furthermore, after polymerization, to suppress off-odors or discoloration of the polymerization solution caused by the decomposition of the chain transfer agent at the polymer ends, and to improve the stability of the acid leaving groups contained in the polymer, the polymer ends can be capped with a thiol compound. Alkyl thiols with 2 to 20 carbon atoms can be used as the thiol compound. In this case, the amount of thiol compound added is 100 to 1,000 mol% relative to the chain transfer agent, and the reaction temperature during end-treatment is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

[0382] In the case of monomers containing hydroxyl groups, the hydroxyl groups can be replaced by acetal groups such as ethoxyethoxy, which are easily deprotected by acids, during polymerization, and then deprotected by weak acids and water after polymerization. Alternatively, they can be replaced by acetyl groups, formyl groups, trimethylacetyl groups, etc., and then subjected to alkaline hydrolysis after polymerization.

[0383] In the case of copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene can be polymerized with other monomers in an organic solvent with the addition of a free radical polymerization initiator and heated. Alternatively, acetoxystyrene or acetoxyvinylnaphthalene can be used, and after polymerization, the acetoxy groups can be deprotected by alkaline hydrolysis to become polyhydroxystyrene or hydroxypolyvinylnaphthalene.

[0384] Specific examples of bases used in alkaline hydrolysis include ammonia and triethylamine. Furthermore, the reaction temperature should preferably be -20 to 100°C, and more preferably 0 to 60°C. The reaction time should preferably be 0.2 to 100 hours, and more preferably 0.5 to 20 hours.

[0385] Furthermore, the amount of each monomer in the monomer solution can be appropriately set, for example, in a manner that forms a preferred content ratio for the aforementioned repeating unit.

[0386] The polymer obtained by the above manufacturing method can be regarded as the final product by the reaction solution obtained by the polymerization reaction, or the powder obtained by the refining step such as adding the polymer liquid to a poor solvent to obtain powder by reprecipitation. Considering the viewpoint of work efficiency or quality stabilization, it is advisable to regard the polymer solution obtained by dissolving the powder obtained by the refining step in the solvent as the final product.

[0387] As specific examples of solvents used at this time, examples include ketones such as cyclohexanone and methyl-2-n-pentyl ketone as described in paragraphs

[0144] to

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

[0388] In the above polymer solution, the polymer concentration is preferably 0.01~30% by mass, and more preferably 0.1~20% by mass.

[0389] The above-mentioned reaction solutions or polymer solutions should be filtered. Filtering removes impurities or gels that could cause defects, thus effectively stabilizing the quality.

[0390] For the materials used in the aforementioned filters, examples include fluorocarbon-based, cellulose-based, nylon-based, polyester-based, and hydrocarbon-based materials. In the filtration step involving chemically amplified resist components, filters made of fluorocarbons such as Teflon (a registered trademark), hydrocarbons such as polyethylene or polypropylene, or nylon are preferable. The pore size of the filter should be appropriately selected to match the desired cleanliness level, preferably below 100 nm, and more preferably below 20 nm. Furthermore, such filters can be used individually or in combination. The filtration method can involve passing the solution through only once, or more preferably, circulating the solution for multiple filtrations. The filtration steps can be performed in any order and number of times during the polymer manufacturing process, preferably filtering the reaction solution after polymerization, the polymer solution, or both.

[0391] [Chemical amplification resist composition]

[0392] The chemically amplified resist composition of the present invention contains a base polymer comprising the above-mentioned polymer as component (A).

[0393] [(A) Basic Polymer]

[0394] The aforementioned polymers may be used alone or in combination with two or more polymers having different composition ratios, Mw and / or Mw / Mn. In addition, (A) the base polymer may contain hydrides of ring-opening metathesis polymers in addition to the aforementioned polymers, and those described in Japanese Patent Application Publication No. 2003-066612 may also be used.

[0395] Furthermore, the chemically amplified resist composition of the present invention preferably contains one or more selected from (B) organic solvents, (C) quenchers, (D) acid generators, (E) surfactants, and (F) dissolution inhibitors. Hereinafter, each component will be described in detail.

[0396] [(B) Organic solvents]

[0397] The chemically amplified resist composition of the present invention may also contain an organic solvent as component (B). As for the organic solvent (B), there is no particular limitation as long as it can dissolve the above-mentioned components and the components described below. 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 monotert-butyl ether acetate; lactones such as GBL; and mixed solvents thereof.

[0398] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and mixtures thereof are preferred as they have particularly good solubility in the base polymer of component (A).

[0399] In the chemically amplified resist composition of the present invention, the content of (B) organic solvent relative to 80 parts by mass of (A) base polymer is preferably 200 to 5,000 parts by mass, more preferably 400 to 3,500 parts by mass. (B) organic solvent may be used alone or in combination with two or more.

[0400] [(C) Quenching agent]

[0401] The chemically amplified resist composition of the present invention may also contain a quencher as component (C). Furthermore, in the present invention, the quencher is a material used to form a desired pattern by capturing the acid generated by the photoacid generator in the chemically amplified resist composition and preventing its diffusion to the unexposed area.

[0402] Specific examples of (C) quenching agents include onium salts represented by the following general formulas (1) or (2).

[0403] [Chemistry 115]

[0404]

[0405] In the above general formula (1), R q1 It is a hydrocarbon group with 1 to 40 carbon atoms, which may contain hydrogen atoms or heteroatoms, but excludes hydrogen atoms at the α-position of the sulfonate group that are substituted with fluorine atoms or fluoroalkyl groups. In the above general formula (2), R q2 A hydrocarbon group consisting of 1 to 40 carbon atoms, which may be hydrogen atoms or may contain heteroatoms.

[0406] As R q1 The hydrocarbon groups representing 1 to 40 carbon atoms include, specifically, 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, and other alkyl groups with 1 to 40 carbon atoms; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norcamphenyl, tricyclic [5.2.1.0] 2,6 Cyclic saturated hydrocarbon groups with 3 to 40 carbon atoms, such as decyl and adamantyl; aryl groups with 6 to 40 carbon atoms, such as phenyl, naphthyl, and anthracene. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon groups may be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms. Similarly, a portion of the -CH2- group in the aforementioned hydrocarbon groups may be replaced by groups containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, the hydrocarbon groups may contain hydroxyl, fluorine, chlorine, bromine, iodine, cyano, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulfonyl lactone ring, carboxylic anhydride (-C(=O)-OC(=O)-), or haloalkyl groups.

[0407] As R q2 The hydrocarbon group represented, specifically, as R q1 In addition to the substituents shown in the specific examples, fluorinated saturated hydrocarbon groups such as trifluoromethyl and trifluoroethyl, or fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl can also be listed.

[0408] Specific examples of onium salt anions represented by the above general formula (1) can be listed below, but are not limited to these.

[0409] [Chemistry 116]

[0410]

[0411] [Chemistry 117]

[0412]

[0413] [Chemistry 118]

[0414]

[0415] Specific examples of onium salt anions represented by the above general formula (2) can be listed below, but are not limited to these.

[0416] [Chemistry 119]

[0417]

[0418] [Chemistry 120]

[0419]

[0420] [Chemistry 121]

[0421]

[0422] In the above general formulas (1) and (2), Mq + It is an onium cation. Preferably, the onium cation is a sulfonium cation represented by the above general formula (cation-1), a monium cation represented by the above general formula (cation-2), or an ammonium cation represented by the above general formula (cation-3).

[0423] [Chemistry 122]

[0424]

[0425] In the above general formula (cation-3), R ct6 ~R ct9 Each can be an independent hydrocarbon group with 1 to 40 carbon atoms, and may also contain heteroatoms. Furthermore, R ct6 and R ct7 They can also bond to each other to form rings with the nitrogen atoms they are bonded to. Specific examples of the aforementioned hydrocarbon groups include those described in the explanations of the general formulas (cation-1) and (cation-2) as R. ct1 ~R ct5 The hydrocarbon groups represented are the same as those shown.

[0426] Specific examples of ammonium cations represented by the above general formula (cation-3) can be listed below, but are not limited to these.

[0427] [Chemistry 123]

[0428]

[0429] As specific examples of onium salts represented by the above general formula (1) or (2), any combination of the above anions and cations can be listed. Furthermore, such onium salts can be easily prepared by ion exchange reactions using known methods in organic chemistry. For example, Japanese Patent Application Publication No. 2007-145797 can be consulted regarding ion exchange reactions.

[0430] The onium salts represented by the above general formula (1) or (2) function as quenchers in the chemically amplified resist composition of the present invention. This is because the relative anions of the above onium salts are conjugate bases of weak acids. The weak acid referred to here means that it exhibits an acidity that cannot deprotect the acid-instable group of the unit containing the acid-instable group used in the base polymer. The onium salts represented by the above general formula (1) or (2) function as quenchers when used in combination with onium salt-type photoacid generators that have a strong acid such as sulfonic acid with α-fluorination as a conjugate base. That is, when an onium salt that generates a strong acid such as sulfonic acid with α-fluorination is mixed with an onium salt that generates a weak acid such as unfluorinated sulfonic acid or carboxylic acid, if the strong acid generated from the photoacid generator is irradiated by high-energy rays and collides with the onium salt having unreacted weak acid anions, the weak acid is released by salt exchange, and an onium salt having strong acid anions is generated. In this process, the strong acid is exchanged for a weak acid with lower catalyst performance. Therefore, overall, the acid is deactivated and its diffusion can be controlled.

[0431] In addition, as the quencher (C), the onium salt having a sulfonium cation and a benzene oxide anion site in the same molecule as described in Japanese Patent No. 6848776 can also be used. Furthermore, the onium salt having a sulfonium cation and a carboxylate anion site in the same molecule as described in Japanese Patent No. 6583136, Japanese Patent Application Publication No. 2020-200311, and the onium salt having a monazine cation and a carboxylate anion site in the same molecule as described in Japanese Patent No. 6274755 can also be used.

[0432] Here, when the photoacid generator of a strong acid is an onium salt, the strong acid generated by high-energy ray irradiation, as described above, can be exchanged into a weak acid. On the other hand, it is believed that the weak acid generated by high-energy ray irradiation is difficult to collide with the unreacted onium salt that generates the strong acid to achieve salt exchange. This is because onium cations more readily form ion pairs with the anions of strong acids.

[0433] In the case where the chemically amplified resist composition of the present invention contains an onium salt represented by the above general formula (1) or (2) as a quencher in (C), its content relative to 80 parts by mass of the base polymer in (A) is preferably 0.1 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass. As long as the onium salt type quencher in component (C) is within the above range, the resolution is good and the sensitivity is not significantly reduced, which is preferable. The onium salt represented by the above general formula (1) or (2) can be used alone or in combination of two or more.

[0434] The chemically amplified resist composition of the present invention may also contain a nitrogen-containing compound as a quencher (C). Specific examples of nitrogen-containing compounds as component (C) include the first-, second-, or third-order amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Application Publication No. 2008-111103, and in particular, amine compounds having hydroxyl groups, ether bonds, ester bonds, lactone rings, cyano groups, or sulfonate bonds. In addition, compounds in which the first- or second-order amine is protected with a carbamate group, as described in Japanese Patent No. 3790649, may also be included.

[0435] Furthermore, sulfonate sulfonate salts with nitrogen-containing substituents can also be used as nitrogen-containing compounds. In such compounds, the unexposed portion functions as a quencher, while the exposed portion loses its quencher properties through neutralization by the acid it generates, thus functioning as a photodegrading base. By using a photodegrading base, the contrast between the exposed and unexposed portions can be further enhanced. For examples of photodegrading bases, see Japanese Patent Application Laid-Open Nos. 2009-109595 and 2012-046501, etc.

[0436] In the case where the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as (C) quencher, its content relative to 80 parts by mass of (A) base polymer is preferably 0.001 to 12 parts by mass, more preferably 0.01 to 8 parts by mass. The aforementioned nitrogen-containing compound may be used alone or in combination of two or more.

[0437] [(D) Acid generating agent]

[0438] The chemically amplified resist composition of the present invention may also contain an (D) acid generating agent, depending on the purpose of the present invention. Examples of such (D) acid generating agents include compounds that generate acid by sensing active light or radiation (photoacid generating agents). There are no particular limitations on photoacid generating agents, as long as they are compounds that generate acid by irradiation with high-energy rays; those that generate sulfonic acid, imine acid, or methyl acid are preferable. Suitable photoacid generating agents include sulfonium salts, sulfonium salts, sulfonyl diazomethanes, N-sulfonyloxyimide, and oxime-O-sulfonate type acid generating agents. Specific examples of acid generating agents can be cited from paragraphs

[0122] to

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

[0439] In addition, as a photoacid generator, sulfonium salts represented by the following general formula (3-1) or sulfonium salts represented by the following general formula (3-2) may also be used.

[0440] [Chemistry 124]

[0441]

[0442] In the above general formulas (3-1) and (3-2), R 101 ~R 105 Each is an independent halogen atom, or may contain heteroatoms, and is a hydrocarbon group with 1 to 20 carbon atoms. Specific examples of the aforementioned halogen atoms and hydrocarbon groups can be listed as R in the descriptions of the above general formulas (cation-1) and (cation-2). ct1 ~R ct5 The halogen atoms and hydrocarbon groups shown are the same. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon groups can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms. Similarly, a portion of the -CH2- group in the aforementioned hydrocarbon groups can be replaced by groups containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, the hydrocarbon groups may contain hydroxyl, fluorine, chlorine, bromine, iodine, cyano, nitro, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulfonyl lactone ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl, etc. Furthermore, R... 101 and R 102 They can also bond with each other to form a ring together with the sulfur atoms they are bonded to. As a specific example of the ring formed in this way, examples can be listed as R in the description of the above general formula (cation-1). ct1 and R ct2 The same type is exemplified by the rings that can be formed by the sulfur atoms bonded to each other.

[0443] Specific examples of cations of sulfonium salts represented by the above general formula (3-1) can be listed as those identical to those exemplified as sulfonium cations represented by the above general formula (cation-1). Furthermore, specific examples of cations of zirconia salts represented by the above general formula (3-2) can be listed as those identical to those exemplified as zirconia cations represented by the above general formula (cation-2).

[0444] In the above general formulas (3-1) and (3-2), Xa - It is anion selected from the following general formulas (3A) to (3D).

[0445] [Chemistry 125]

[0446]

[0447] In the above general formula (3A), R fa A hydrocarbon group consisting of 1 to 40 carbon atoms, which may contain fluorine atoms or heteroatoms. This hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. As a specific example, R in the general formula (3A') described later can be listed. fa1 The examples shown in the description are the same.

[0448] The anion represented by the above general formula (3A) should preferably be represented by the following general formula (3A').

[0449] [Chemistry 126]

[0450]

[0451] In the above general formula (3A'), R HF It can be a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group.

[0452] In the above general formula (3A'), R fa1 The hydrocarbon group may contain heteroatoms and has 1 to 38 carbon atoms. The heteroatoms are preferably oxygen, nitrogen, sulfur, or halogen atoms, but oxygen is more preferred. Considering the high resolution that can be obtained in the formation of fine patterns, hydrocarbon groups with 6 to 30 carbon atoms are particularly preferred.

[0453] R fa1The hydrocarbon groups represented by carbon numbers from 1 to 38 can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include alkyl groups with 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, heptadecanyl, and eicosyl; cyclic saturated hydrocarbon groups with 3 to 38 carbon atoms, such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norcamphenyl, norcamphenylmethyl, tricyclodecyl, tetracyclododecyl, tetracyclododecylmethyl, and dicyclohexylmethyl; unsaturated aliphatic hydrocarbon groups with 2 to 38 carbon atoms, such as allyl and 3-cyclohexenyl; aryl groups with 6 to 38 carbon atoms, such as phenyl, 1-naphthyl, and 2-naphthyl; aralkyl groups with 7 to 38 carbon atoms, such as benzyl and diphenylmethyl; and groups obtained by combining them.

[0454] Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. Similarly, a portion of the -CH2- group in the aforementioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulopentalide rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc. Furthermore, oxygen atoms are preferred as the aforementioned heteroatoms. Specific examples of hydrocarbon groups containing heteroatoms include tetrahydrofuranyl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamidemethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, 3-oxocyclohexyl, etc.

[0455] For details regarding the synthesis of sulfonium salts containing anions represented by the above general formula (3A'), please refer to Japanese Patent Application Publication Nos. 2007-145797, 2008-106045, 2009-007327, and 2009-258695. Furthermore, sulfonium salts described in Japanese Patent Application Publication Nos. 2010-215608, 2012-041320, 2012-106986, and 2012-153644 are also suitable.

[0456] Specific examples of anions represented by the above general formula (3A) can be listed below, but are not limited to these. Furthermore, in the following formula, Ac represents an acetyl group.

[0457] [Chemistry 127]

[0458]

[0459] [Chemistry 128]

[0460]

[0461] [Chemistry 129]

[0462]

[0463] [Chemistry 130]

[0464]

[0465] In the above general formula (3B), R fb1 and R fb2 Each of the above-mentioned hydrocarbon groups consists independently of a fluorine atom or may contain heteroatoms and has 1 to 40 carbon atoms. These hydrocarbon groups may be saturated or unsaturated, and may be linear, branched, or cyclic. As a specific example, R in the above general formula (3A') can be listed. fa1 The hydrocarbon groups represented are the same. As R fb1 and R fb2 It should preferably be a fluorine atom or a straight-chain fluorinated alkyl group having 1 to 4 carbon atoms. Additionally, R... fb1 With R fb2 They can also bond with each other and with the groups they are bonded to (-CF2-SO2-N). - -SO2-CF2-) together form a ring, at which point R fb1 With R fb2 The groups obtained by mutual bonding should preferably be fluorinated ethylidene or fluorinated propyleneide.

[0466] In the above general formula (3C), R fc1 R fc2 and R fc3 Each of the above-mentioned hydrocarbon groups consists independently of a fluorine atom or may contain heteroatoms and has 1 to 40 carbon atoms. These hydrocarbon groups may be saturated or unsaturated, and may be linear, branched, or cyclic. As a specific example, R in the above general formula (3A') can be listed. fa1 The hydrocarbon groups represented are the same. As R fc1 R fc2 and R fc3 It should preferably be a fluorine atom or a straight-chain fluorinated alkyl group having 1 to 4 carbon atoms. Additionally, R... fc1 With R fc2 They can also bond with each other and with the groups they are bonded to (-CF2-SO2-C). - -SO2-CF2-) together form a ring, at which point R fc1 With R fc2The groups obtained by mutual bonding should preferably be fluorinated ethylidene or fluorinated propyleneide.

[0467] In the above general formula (3D), R fd It can be a hydrocarbon group with 1 to 40 carbon atoms, and may also contain heteroatoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. As a specific example, R in the above general formula (3A') can be listed. fa1 The hydrocarbon groups represented are the same as those shown.

[0468] For details on the synthesis of sulfonium salts containing anions represented by the above general formula (3D), please refer to Japanese Patent Application Publication Nos. 2010-215608 and 2014-133723.

[0469] Specific examples of anions represented by the above general formula (3D) can be listed below, but are not limited to these.

[0470] [Chemistry 131]

[0471]

[0472] [Chemistry 132]

[0473]

[0474] Furthermore, the photoacid generator containing the anion represented by the above general formula (3D) does not have a fluorine atom at the α-position of the sulfonyl group, but has two trifluoromethyl groups at the β-position, thus possessing sufficient acidity to cleave the acid-unstable groups in the base polymer. Therefore, it can be used as a photoacid generator.

[0475] As a photoacid generator, it can also be appropriately represented by the following general formula (4).

[0476] [Chemistry 133]

[0477]

[0478] In the above general formula (4), R 201 and R 202 Each can be an independent hydrocarbon group with 1 to 30 carbon atoms, and may also contain heteroatoms. R 203 It can also contain a hydrocarbon group with 1 to 30 carbon atoms and a heteroatom. Furthermore, R 201 R 202 and R 203 Any two of them can also bond to each other to form a ring together with the sulfur atoms they are bonded to. In this case, as a specific example of the above-mentioned ring, we can list the example of R in the description of the above general formula (cation-1). ct1 and R ct2The examples illustrating the same principle are those where the sulfur atoms bonded to each other can form rings together.

[0479] R 201 and R 202 The hydrocarbon group representing 1 to 30 carbon atoms can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include alkyl groups with 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornel, oxanorbornel, and tricyclic [5.2.1.0] 2,6 Cyclic saturated hydrocarbon groups with 3 to 30 carbon atoms, such as decyl and adamantyl; aryl groups with 6 to 30 carbon atoms, such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, tert-butylnaphthyl, anthracene, etc.; and groups obtained by combining them. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms. A portion of the -CH2- group in the aforementioned hydrocarbon group can also be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sulcinolone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0480] R 203The alkylene groups representing 1 to 30 carbon atoms can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, and heptadecane-1,17-diyl. - Alkyl groups with 1 to 30 carbon atoms, such as dimethyl alkane; cyclopentane dimethyl, cyclohexane dimethyl, norcamphene dimethyl, adamantane dimethyl, etc., with 3 to 30 carbon atoms; aryl groups with 6 to 30 carbon atoms, 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, etc.; and groups obtained by combining them. Furthermore, some or all of the hydrogen atoms in the aforementioned alkylene groups can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms. Similarly, a portion of the -CH2- group in the aforementioned alkylene groups can be replaced by groups containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, the groups may contain hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone, sulfonate, carboxylic anhydride (-C(=O)-OC(=O)-), or haloalkyl groups. Oxygen atoms are preferred as the heteroatom in these heteroatoms.

[0481] In the above general formula (4), L A It is a hydrocarbon group with 1 to 20 carbon atoms, which may be a single bond, an ether bond, or may contain heteroatoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be listed as R... 203 The analyte groups represented are the same.

[0482] In the above general formula (4), X A X B X C and X D Each can be independently a hydrogen atom, a fluorine atom, or a trifluoromethyl atom. However, X A X B X C and X D At least one of them is a fluorine atom or a trifluoromethyl group.

[0483] In the above general formula (4), k is an integer from 0 to 3.

[0484] As the photoacid generating agent represented by the above general formula (4), it is preferable to be represented by the following general formula (4').

[0485] [Chemistry 134]

[0486]

[0487] In the above general formula (4'), L A Same as above. R HF It can be a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R 301 R 302 and R 303 Each of these groups is an independent hydrocarbon group with 1 to 20 carbon atoms, which may also contain heteroatoms. These hydrocarbon groups may be saturated or unsaturated, and may be linear, branched, or cyclic. As a specific example, R in the above general formula (3A') can be listed. fa1 The hydrocarbon groups represented are identical. x and y are each independent integers from 0 to 5. z is an integer from 0 to 4.

[0488] As a specific example of a photoacid generator represented by the above general formula (4), the same example can be cited as the photoacid generator represented by formula (2) in Japanese Patent Application Publication No. 2017-026980.

[0489] Among the aforementioned photoacid generators, those containing anions represented by the general formula (3A') or (3D) exhibit low acid diffusion and excellent solvent solubility, making them particularly desirable. Furthermore, those containing anions represented by the general formula (4') exhibit extremely low acid diffusion, making them particularly desirable.

[0490] In addition, as other acid generating agents, sulfonium salts and sulfonium salts containing anions having an aromatic ring substituted with an iodine atom, represented by the following general formulas (5-1) or (5-2), may also be used.

[0491] [Chemistry 135]

[0492]

[0493] In the above general formulas (5-1) and (5-2), p is 1, 2, or 3. q and r are integers that satisfy 1≤q≤5, 0≤r≤3, and 1≤q+r≤5. q should preferably be 1, 2, or 3, and more preferably 2 or 3. r should preferably be 0, 1, or 2.

[0494] In the above general formulas (5-1) and (5-2), L 1 It is a saturated hydrocarbon group with 1 to 6 carbon atoms, which may be a single bond, ether bond, ester bond, or may also contain ether or ester bonds. The above-mentioned saturated hydrocarbon group can be linear, branched, or cyclic.

[0495] In the above general formulas (5-1) and (5-2), L 2 When p is 1, it is a single bond or a divalent linker with 1 to 20 carbon atoms; when p is 2 or 3, it is a (p+1) valent linker with 1 to 20 carbon atoms. The linker may also contain oxygen, sulfur, or nitrogen atoms.

[0496] In the above general formulas (5-1) and (5-2), R 401 The carbon groups are hydroxyl, carboxyl, fluorine, chlorine, bromine, amino, or may contain fluorine, chlorine, bromine, hydroxyl, amino, or ether bonds, and are hydrocarbon groups with 1 to 20 carbon atoms, hydrocarbon oxy groups with 1 to 20 carbon atoms, hydrocarbon carbonyl groups with 2 to 20 carbon atoms, hydrocarbon carbonyl oxy groups with 2 to 20 carbon atoms, or hydrocarbon sulfonyl oxy groups with 1 to 20 carbon atoms, or -N(R) groups. 401A (R) 401B ), -N(R 401C )-C(=O)-R 401D 、or -N(R 401C )-C(=O)-OR 401D R 401A and R 401B Each is independently a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. R 401C It is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms, and may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbon group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms. R 401D It is an aliphatic hydrocarbon group with 1 to 16 carbon atoms, an aryl group with 6 to 14 carbon atoms, or an aralkyl group with 7 to 15 carbon atoms. It may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxy group with 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group with 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyl oxy group with 2 to 6 carbon atoms. The aforementioned aliphatic hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. The aforementioned hydrocarbon group, hydrocarbon oxy group, hydrocarbon carbonyl group, hydrocarbon oxycarbonyl group, hydrocarbon carbonyl oxy group, and hydrocarbon sulfonyl oxy group can be linear, branched, or cyclic. When p and / or r is 2 or more, each R... 401 They can be the same or different.

[0497] Among these, as R 401 It is advisable to use hydroxyl groups or -N(R) 401C )-C(=O)-R 401D -N(R) 401C )-C(=O)-OR 401D Fluorine atoms, chlorine atoms, bromine atoms, methyl groups, methoxy groups, etc.

[0498] In the above general formulas (5-1) and (5-2), Rf1 ~Rf 4 Each is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl atom, at least one of which is a fluorine atom or a trifluoromethyl atom. Furthermore, Rf 1 With Rf 2 They can also combine to form carbonyl groups. Rf is particularly suitable. 3 and Rf 4 All are fluorine atoms.

[0499] In the above general formulas (5-1) and (5-2), R 402 ~R 406 Each of these hydrocarbon groups consists independently of a halogen atom or may contain heteroatoms and has 1 to 20 carbon atoms. These hydrocarbon groups can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be given as those described in the explanations of the above general formulas (cation-1) and (cation-2) as R. ct1 ~R ct5 The hydrocarbon groups exemplified are the same. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon groups may be substituted by hydroxyl, carboxyl, halogen, cyano, nitro, mercapto, sulfonyl lactone ring, sulfonyl, or groups containing sulfonium salts; and a portion of the -CH2- group in the aforementioned hydrocarbon groups may be substituted by ether, ester, carbonyl, amide, carbonate, or sulfonate bonds. Additionally, R 402 and R 403 They can also bond to each other to form a ring with the sulfur atoms they are bonded to. In this case, as a specific example of the aforementioned ring, examples can be listed as R in the description of the general formula (cation-1) above. ct1 and R ct2 The same type is exemplified by the rings that can be formed by mutual bonding and together with the sulfur atoms they are bonded to.

[0500] Specific examples of cations of sulfonium salts represented by the above general formula (5-1) can be listed as those identical to those exemplified as sulfonium cations represented by the above general formula (cation-1). Furthermore, specific examples of cations of zirconia salts represented by the above general formula (5-2) can be listed as those identical to those exemplified as zirconia cations represented by the above general formula (cation-2).

[0501] Specific examples of onium salt anions represented by the above general formulas (5-1) or (5-2) are shown below, but are not limited to these.

[0502] [Chemistry 136]

[0503]

[0504] [Chemistry 137]

[0505]

[0506] [Chemistry 138]

[0507]

[0508] [Chemistry 139]

[0509]

[0510] [Chemistry 140]

[0511]

[0512] [Chemistry 141]

[0513]

[0514] [Chemistry 142]

[0515]

[0516] [Chemistry 143]

[0517]

[0518] [Chemistry 144]

[0519]

[0520] [Chemistry 145]

[0521]

[0522] [Chemistry 146]

[0523]

[0524] [Chemistry 147]

[0525]

[0526] [Chemistry 148]

[0527]

[0528] [Chemistry 149]

[0529]

[0530] [Chemistry 150]

[0531]

[0532] [Chemistry 151]

[0533]

[0534] [Chemistry 152]

[0535]

[0536] [Chemistry 153]

[0537]

[0538] [Chemistry 154]

[0539]

[0540] [Chemistry 155]

[0541]

[0542] [Chemistry 156]

[0543]

[0544] [Chemistry 157]

[0545]

[0546] In the case where the chemically amplified resist composition of the present invention contains an acid-generating agent (D), its content relative to 80 parts by mass of the base polymer (A) is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 20 parts by mass. As long as the amount of acid-generating agent in component (D) is within the above range, the resolution is good, and there is no concern about impurities being generated after development or during stripping of the resist film, which is therefore preferable. The acid-generating agent (D) can be used alone or in combination of two or more.

[0547] [(E) Surfactant]

[0548] The chemically amplified resist composition of the present invention may also contain a surfactant as component (E). Regarding the surfactant (E), it is preferable to be a surfactant that is insoluble or sparingly soluble in water but soluble in alkaline developing solution, or a surfactant that is insoluble or sparingly soluble in both water and alkaline developing solution. Such surfactants can be referred to in Japanese Patent Application Publication No. 2010-215608 or Japanese Patent Application Publication No. 2011-016746.

[0549] Regarding surfactants that are insoluble or poorly soluble in water and alkaline developing solutions, among the surfactants described in the above-mentioned announcement, FC-4430 (manufactured by 3M Corporation), Surflon (registered trademark) S-381 (manufactured by AGC SEIMI CHEMICAL 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 general formula (surf-1), etc.

[0550] [Chemistry 158]

[0551]

[0552] Here, R, Rf, A, B, C, m, and n are irrelevant to the foregoing description and apply only to the above general formula (surf-1). R is an aliphatic group with 2 to 5 carbon atoms, valent to 2 to 4. Examples of such aliphatic groups include ethylene, 1,4-butylene, 1,2-propylene, 2,2-dimethyl-1,3-propylene, and 1,5-pentanediol for divalent groups, and the following for trivalent or tetravalent groups.

[0553] [Chemistry 159]

[0554]

[0555] (In the formula, the dashed lines represent atomic bonds, which are partial structures derived from glycerol, trimethylolethane, trimethylolpropane, and neopentyl tetrol, respectively.)

[0556] Among these, 1,4-butylene, 2,2-dimethyl-1,3-propylene, etc. are preferred.

[0557] 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, an integer from 2 to 4. A is 1. B is an integer from 2 to 25, preferably an integer from 4 to 20. C is an integer from 0 to 10, preferably 0 or 1. Furthermore, the arrangement of the constituent units in the above general formula (surf-1) is not particularly specified; they can be block-bonded or randomly bonded. For details on the manufacture of surfactants based on partially fluorinated oxyheterocyclic butane ring-opening polymer systems, please refer to the specification in US Patent No. 5,650,483, etc.

[0558] Surfactants that are insoluble or sparingly soluble in water but soluble in alkaline developing solutions are used in ArF immersion lithography when no resist protective film is used. By aligning with the surface of the resist film, they reduce the penetration or leaching of water. Therefore, they are useful for inhibiting the dissolution of water-soluble components from the resist film, thus reducing damage to the exposure equipment. Furthermore, they are useful because they become soluble in alkaline aqueous solutions after exposure or post-exposure baking (PEB) and are less likely to become impurities that cause defects. Such surfactants, which are insoluble or sparingly soluble in water but soluble in alkaline developing solutions, are polymeric surfactants, also known as hydrophobic resins, and are particularly suitable for those with high water repellency that enhances hydrophobic properties.

[0559] Specific examples of such polymeric surfactants include those containing at least one repeating unit selected from the repeating units represented by the following general formulas (6A) to (6E).

[0560] [Chemistry 160]

[0561]

[0562] In the above general formulas (6A)~(6E), R B It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. W 1 It can be -CH2-, -CH2CH2-, -O-, or two separate -H groups. R s1 Each is independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R s2 It is a single bond, or a straight-chain or branched hydrocarbon group with 1 to 5 carbon atoms. R s3 Each is independently a hydrogen atom, a hydrocarbon group with 1 to 15 carbon atoms, a fluorinated hydrocarbon group, or an acid-labile group. In R s3 In the case of hydrocarbon groups or fluorinated hydrocarbon groups, ether bonds or carbonyl groups may also be inserted between carbon-carbon bonds. R s4 R is a hydrocarbon group or fluorinated hydrocarbon group with a valence of (u+1) and having 1 to 20 carbon atoms. u is an integer from 1 to 3. s5 Each is independently a hydrogen atom, or -C(=O)-OR sa The group indicated by R. sa It is a fluorinated hydrocarbon group with 1 to 20 carbon atoms. R s6 It is a hydrocarbon group or fluorinated hydrocarbon group with 1 to 15 carbon atoms, and ether bonds or carbonyl groups may be inserted between its carbon-carbon bonds.

[0563] R s1The hydrocarbon group representing 1 to 10 carbon atoms should preferably be a saturated hydrocarbon group, and can be linear, branched, or cyclic. Specific examples include alkyl groups with 1 to 10 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; and cyclic saturated hydrocarbon groups with 3 to 10 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornel. Among these, those with 1 to 6 carbon atoms are preferred.

[0564] R s2 The alkylene group represented should preferably be a saturated alkylene group, and can be linear, branched, or cyclic. Specific examples include methylene, ethylene, propylene, butylene, and pentylene.

[0565] R s3 or R s6 The hydrocarbon group represented can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include aliphatic unsaturated hydrocarbon groups such as saturated hydrocarbon groups, alkenyl groups, and alkynyl groups, which are preferably saturated hydrocarbon groups. As a specific example of the aforementioned saturated hydrocarbon group, when represented as R... s1 In addition to the hydrocarbon groups exemplified, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, etc., may also be listed. As R s3 or R s6 Specific examples of fluorinated hydrocarbon groups may be listed where some or all of the hydrogen atoms of the carbon atom bonded to the aforementioned hydrocarbon group are replaced by fluorine atoms. As described above, ether bonds or carbonyl groups may also be inserted between their carbon-carbon bonds.

[0566] As R s3 Specific examples of acid-instable groups include groups represented by the general formulas (AL-1) to (AL-3) above, trialkylsilyl groups with alkyl groups having 1 to 6 carbon atoms, and alkyl groups containing oxygen groups having 4 to 20 carbon atoms.

[0567] R s4 The (u+1) valence hydrocarbon group or fluorinated hydrocarbon group can be any of the following: linear, branched, or cyclic. As specific examples, groups obtained by removing u hydrogen atoms from the above-mentioned hydrocarbon group or fluorinated hydrocarbon group can be listed.

[0568] As R saThe fluorinated hydrocarbon group represented should preferably be saturated and can be linear, branched, or cyclic. Specific examples include hydrocarbon groups in which some or all of the hydrogen atoms are replaced by fluorine atoms. Specifically, 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-dodecylfluoroheptyl, 2-(perfluorobutyl)ethyl, 2-(perfluorohexyl)ethyl, 2-(perfluorooctyl)ethyl, 2-(perfluorodecyl)ethyl, etc.

[0569] Specific examples of repeating units represented by any of the above general formulas (6A) to (6E) can be listed below, but are not limited to these. Furthermore, in the following formula, R... B Same as above.

[0570] [Chemistry 161]

[0571]

[0572] [Chemistry 162]

[0573]

[0574] [Chemistry 163]

[0575]

[0576] [Chemistry 164]

[0577]

[0578] [Chemistry 165]

[0579]

[0580] The aforementioned polymeric surfactants may also contain repeating units other than those represented by the general formulas (6A) to (6E). Specific examples of other repeating units include repeating units obtained from methacrylic acid or α-trifluoromethacrylic acid derivatives. In polymeric surfactants, the content of repeating units represented by the general formulas (6A) to (6E) is preferably 20 mol% or more, more preferably 60 mol% or more, and even more preferably 100 mol% of all repeating units.

[0581] The Mw of the aforementioned polymeric surfactant is preferably 1,000 to 500,000, more preferably 3,000 to 100,000. The Mw / Mn ratio is preferably 1.0 to 2.0, more preferably 1.0 to 1.6.

[0582] As a method for synthesizing the above-mentioned polymeric surfactants, one method is to polymerize monomers containing unsaturated bonds, which are given repeating units represented by the above general formulas (6A) to (6E) and other repeating units as needed, in an organic solvent, add a free radical polymerization initiator, and heat the solvent. Specific examples of organic solvents used in polymerization include toluene, benzene, THF, diethyl ether, and dioxane. Specific examples of free radical polymerization initiators include AIBN, azobisisobutyronitrile, dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The reaction temperature is preferably 50 to 100°C. The reaction time is preferably 4 to 24 hours. Acid-labile groups can be used directly after being introduced into the monomer, or they can be protected or partially protected after polymerization.

[0583] In the synthesis of the aforementioned polymeric surfactants, known chain transfer agents such as dodecyl mercaptan or 2-mercaptoethanol can be used to adjust the molecular weight. In this case, the amount of such chain transfer agent added relative to the total molar number of monomers polymerized should preferably be 0.01 to 10 mol%.

[0584] In the case where the chemically amplified resist composition of the present invention contains surfactant (E), its content relative to 80 parts by mass of the base polymer (A) is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 10 parts by mass. As long as the content of surfactant (E) is 0.1 parts by mass or more, the receding contact angle between the resist film surface and water is sufficiently increased; as long as it is 50 parts by mass or less, the dissolution rate of the resist film surface to the developer is low, thus sufficiently maintaining the height of the formed fine pattern. Surfactant (E) can be used alone or in combination of two or more.

[0585] [(F) Dissolution Inhibitor]

[0586] The chemically amplified resist composition of the present invention may also contain a dissolution inhibitor as component (F). In the case where the chemically amplified resist composition of the present invention is positive, by incorporating the dissolution inhibitor (F), the difference in dissolution rate between the exposed and unexposed areas can be further increased, thereby further improving resolution.

[0587] Specific examples of the above-mentioned (F) dissolution inhibitors include compounds in which the hydrogen atoms of the phenolic hydroxyl groups of a compound having a molecular weight preferably of 100 to 1,000, more preferably 150 to 800, and containing two or more phenolic hydroxyl groups are substituted with acid-indestabilizing groups at a ratio of 0 to 100 mol% in all respects; or compounds in which the hydrogen atoms of the carboxyl groups of a compound containing carboxyl groups are substituted with acid-indestabilizing groups at an average ratio of 50 to 100 mol% in all respects. Specifically, examples include compounds in which the hydrogen atoms of the hydroxyl and carboxyl groups of bisphenol A, triphenol, phenolphthalein, cresol phenolic varnish, naphtholic acid, adamantane carboxylic acid, and cholic acid are substituted with acid-indestabilizing groups, such as those described in paragraphs

[0155] to

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

[0588] In the case of the chemically amplified resist composition of the present invention containing (F) a dissolution inhibitor, the content of the inhibitor is preferably 0 to 50 parts by mass relative to 80 parts by mass of (A) the base polymer, and more preferably 5 to 40 parts by mass.

[0589] [(G) Other ingredients]

[0590] The chemically amplified resist composition of the present invention, as other components (G), may also contain compounds that generate acid through acid decomposition (acid-increasing compounds), organic acid derivatives, fluorinated alcohols, water-repellent improvers, etc. As the aforementioned acid-increasing compounds, reference can be made to the compounds described in Japanese Patent Application Publication No. 2009-269953 or Japanese Patent Application Publication No. 2010-215608. When containing the aforementioned acid-increasing compounds, their content relative to 80 parts by mass of the base polymer (A) is preferably 0 to 5 parts by mass, more preferably 0 to 3 parts by mass. As long as the content is within this range, acid diffusion can be controlled, and it is less likely to cause distinguishable degradation or pattern shape degradation. As the aforementioned organic acid derivatives and fluorinated alcohols, reference can be made to the compounds described in Japanese Patent Application Publication No. 2009-269953 or Japanese Patent Application Publication No. 2010-215608.

[0591] The aforementioned water-repellent improver can be used in immersion lithography without a top coat. As the aforementioned water-repellent improver, polymers containing fluorinated alkyl groups, polymers containing 1,1,1,3,3,3-hexafluoro-2-propanol residues with a specific structure, etc., are preferable, especially those exemplified in Japanese Patent Application Publication Nos. 2007-297590 and 2008-111103. The aforementioned water-repellent improver needs to be dissolved in alkaline or organic solvent developing solutions. The aforementioned water-repellent improver having specific 1,1,1,3,3,3-hexafluoro-2-propanol residues exhibits good solubility in developing solutions. As a water-repellent improver, polymers containing repeating units containing amino or amine salts are highly effective in preventing the evaporation of acid in PEB and thus preventing poor opening of the hole pattern after development. In the case where the chemically amplified corrosion resist composition of the present invention contains the above-mentioned water repellency improver, its content relative to 80 parts by weight of (A) base polymer is preferably 0 to 20 parts by weight, more preferably 0.5 to 10 parts by weight.

[0592] [Pattern Formation Method]

[0593] When the chemically amplified resist composition of the present invention is used in the manufacture of various integrated circuits, known photolithography techniques can be applied. For example, as a patterning method, a method comprising the following steps can be listed: forming a resist film on a substrate using the chemically amplified resist composition described above, exposing the resist film to high-energy rays, and developing the exposed resist film using a developer.

[0594] First, the chemically amplified resist composition of the present invention is coated onto a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflective film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) with a film thickness of 0.01 to 2.0 μm using a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor blade coating. The substrate is then pre-baked on a hot plate, preferably at 60 to 150°C for 10 to 30 seconds, more preferably at 80 to 120°C for 30 to 20 seconds, to form a resist film.

[0595] Then, the resist film is exposed using high-energy radiation. Examples of such high-energy radiation include ultraviolet light, far-ultraviolet light, electron beams (EB), extreme ultraviolet light (EUV) with wavelengths of 3–15 nm, X-rays, soft X-rays, excimer lasers, gamma rays, and synchrotron radiation. When using ultraviolet light, far-ultraviolet light, EUV, X-rays, soft X-rays, excimer lasers, gamma rays, or synchrotron radiation as high-energy radiation, the exposure dose is preferably about 1–200 mJ / cm², either directly or using a mask to form the desired pattern. 2 It is more appropriate to have a concentration of approximately 10~100 mJ / cm. 2 Irradiation is performed in the manner described above. When using EB as the aforementioned high-energy ray, the exposure dose should preferably be approximately 0.1~100 μC / cm. 2 The optimal temperature range is approximately 0.5~50 μC / cm. 2 The pattern can be drawn directly or using a mask to form the desired pattern. The chemically amplified resist composition of this invention is particularly suitable for fine patterning using high-energy rays, such as ArF excimer lasers with a wavelength of 193 nm, KrF excimer lasers with a wavelength of 248 nm, EB, or EUV, X-rays, soft X-rays, gamma rays, or synchrotron radiation with wavelengths of 3-15 nm. Specifically, ArF excimer lasers with a wavelength of 193 nm, KrF excimer lasers with a wavelength of 248 nm, electron beams, or extreme ultraviolet radiation with wavelengths of 3-15 nm are preferred as the aforementioned high-energy rays.

[0596] Alternatively, after exposure, PEB can be performed on a heating plate at a temperature of 60-150°C for 10-30 seconds, or more preferably 80-120°C for 30-20 seconds.

[0597] After exposure or PEB, use a developer solution containing 0.1-10% by mass, preferably 2-5% by mass, of an alkaline aqueous solution of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc., and develop it for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, using conventional methods such as dip, puddle, or spray. The parts exposed to light dissolve in the developer solution, while the unexposed parts do not dissolve, thus forming the desired positive pattern on the substrate.

[0598] Organic solvent developers can also be used instead of the aforementioned alkaline aqueous solutions to obtain negative patterns. Specific examples of organic solvent developers used in this manner include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methyl acetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, methyl valerate, methyl valerate, and methyl crotonate. Examples of organic solvent developers include 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, and 2-phenylethyl acetate. These organic solvent developers can be used alone or in mixtures of two or more.

[0599] Rinsing may also be performed at the end of development. The rinsing solution should preferably be miscible with the developer and should not dissolve the resist film. Suitable solvents include alcohols with 3 to 10 carbon atoms, ether compounds with 8 to 12 carbon atoms, alkanes with 6 to 12 carbon atoms, alkenes, alkynes, and aromatic solvents.

[0600] Specific examples of alcohols with 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, and 2,3-dimethyl-2-butanol. Alcohols, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol, etc.

[0601] Specific examples of the ether compounds with 8 to 12 carbon atoms mentioned above include di-n-butyl ether, diisobutyl ether, disec-butyl ether, di-n-pentyl ether, diisopentyl ether, disec-pentyl ether, ditert-pentyl ether, and di-n-hexyl ether.

[0602] Specific examples of alkanes with 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, and cyclononane. Specific examples of alkenes with 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Specific examples of alkynes with 6 to 12 carbon atoms include hexyne, heptyne, and octyne.

[0603] Specific examples of solvents for the aforementioned aromatic systems include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0604] Rinsing can reduce the collapse or defects in the resist pattern. Furthermore, rinsing is not always necessary; it can be omitted to reduce solvent usage.

[0605] Alternatively, the developed hole or groove pattern can be shrunk using heat transfer, RELACS, or DSA techniques. A shrinkage agent is applied to the hole pattern, and during baking, diffusion from the acid catalyst in the resist film causes cross-linking of the shrinkage agent on the surface of the resist film, adhering to the sidewalls of the hole pattern. The baking temperature should be 70–180°C, more preferably 80–170°C, and the baking time should be 10–300 seconds to remove excess shrinkage agent and reduce the size of the hole pattern.

[0606] Example

[0607] The present invention will be specifically described below with examples of synthesis, comparative synthesis, embodiments, and comparative examples, but the present invention is not limited to the embodiments described below. Furthermore, the apparatus used is as described below.

[0608] MALDI TOF-MS: S3000 manufactured by Nippon Electronics Co., Ltd.

[0609] As raw materials for the synthesis of onium salt type monomers, the following aromatic nitriles (SM-a1~a4), styrene derivatives (SM-b1~b4), potassium tert-butoxy alcohols and alcohols (SM-c1~c5), fluoroalcohol derivatives (SM-d1~d3), sulfonium salts and tungsten salts (SM-e1~e5) were used.

[0610] [Chemistry 166]

[0611]

[0612] [Chemistry 167]

[0613]

[0614] [Chemistry 168]

[0615]

[0616] [Chemistry 169]

[0617]

[0618] [Chemistry 170]

[0619]

[0620] [1] Synthesis of onium salt monomers

[0621] [Synthetic Example 1-1] Synthesis of Onium Salt Monomer (a-1)

[0622] Onium salt monomers (a-1) were synthesized via the following pathway.

[0623] [Chemistry 171]

[0624]

[0625] (1) Synthesis of intermediate In-1

[0626] Under nitrogen atmosphere, 26.4 g of raw material (SM-b1), 33.2 g of potassium carbonate, and 200 g of NMP (N-methyl-2-pyrrolidone) were added to the reaction vessel and uniformly dispersed at an internal temperature of 40°C. Then, 53.0 g of raw material (SM-a1), pre-dissolved in 50 g of NMP, was added dropwise over 30 minutes. After the addition, the temperature inside the reaction vessel was raised to 60°C, and the reaction was carried out for 6 hours. Afterward, the reaction solution was cooled, and 500 ml of IPE (diisopropyl ether) and 200 g of ultrapure water were added to form a homogeneous solution. The solution was then transferred to a separatory funnel to remove the separated aqueous layer. The solution was washed with 100 g of 5% sodium hydroxide aqueous solution, followed by five washes with 100 ml of ultrapure water to recover the organic layer. After distilling off the organic layer, 71.5 g of intermediate (In-1) was obtained (yield 98%).

[0627] (2) Synthesis of intermediate In-2

[0628] Under nitrogen atmosphere, a homogeneous solution was prepared in a reaction vessel by adding 18.5 g of the starting material (SM-cl) to 200 g of THF (tetrahydrofuran). After homogenization, 54.8 g of the intermediate (In-1), pre-dissolved in 150 g of THF, was added dropwise over 60 minutes in a water bath. Following the addition, the reaction vessel was heated in an oil bath and reacted under reflux for 6 hours. After cooling the reaction solution, 500 ml of IPE and 200 g of ultrapure water were added to prepare a homogeneous solution. This solution was then transferred to a separatory funnel, and the separated aqueous layer was removed. The solution was washed five times with 100 ml of ultrapure water to recover the organic layer. After distilling off the organic layer, 57.4 g of the intermediate (In-2) ​​was obtained (yield 91%).

[0629] (3) Synthesis of intermediate In-3

[0630] Under nitrogen atmosphere, 54.5 g of intermediate (In-2), 17.2 g of potassium hydroxide (85% purity), 150 g of EtOH (ethanol), and 150 g of ultrapure water were added to a reaction vessel, and the reaction was carried out at an internal temperature of 90°C for 24 hours. After cooling the reaction solution, 500 ml of ethyl acetate was added, followed by the slow addition of 210 g of 3% hydrochloric acid aqueous solution under ice bath conditions to neutralize the reaction solution. After neutralization, the solution was transferred to a separatory funnel, and the separated aqueous layer was removed. The solution was then washed five times with 100 ml of ultrapure water to recover the organic layer. After distilling off the organic layer, recrystallization was performed with IPE to obtain 44.7 g of intermediate (In-3) (yield 78%).

[0631] (4) Synthesis of intermediate In-4

[0632] Under nitrogen atmosphere, 39.4 g of intermediate (In-3), 1.1 g of DMAP (4-dimethylaminopyridine), 19.0 g of starting material (SM-d1), and 200 g of dichloromethane were added to a reaction vessel and a homogeneous dispersion was prepared in an ice bath. 19.0 g of EDC·HCl (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride) was divided into five portions and added every 10 minutes to the reaction vessel, which had been cooled in an ice bath. After stirring for 1 hour under cooling, the reaction was carried out at room temperature for 24 hours. 100 g of 3% HCl aqueous solution was added to stop the reaction. After the reaction stopped, the mixture was transferred to a separatory funnel, and the separated aqueous layer was removed. The mixture was then washed five times with 100 ml of ultrapure water to recover the organic layer. After distilling off the organic layer, recrystallization was performed using IPE to obtain 50.8 g of intermediate (In-4) as white crystals (yield 81%).

[0633] (5) Synthesis of onium salt type monomer (a-1)

[0634] Under nitrogen atmosphere, 48.7 g of intermediate (In-4), 27.9 g of (SM-e1), 400 g of dichloromethane, and 150 g of ultrapure water were added to the reaction vessel. After stirring for 30 minutes, the organic layer was transferred to a separatory funnel, and the aqueous layer was removed. The mixture was further washed five times with 150 g of ultrapure water, and the organic layer was recovered and concentrated under reduced pressure. The concentrate was purified by silica gel chromatography to obtain 46.2 g of the onium salt monomer (a-1) of the target compound as white crystals (78% yield).

[0635] MALDI TOF-MS: POSITIVE M + 261 (equivalent to C) 18 H 13 S + )

[0636] NEGATIVE M - 581 (equivalent to C) 20 H 20 F2IO7S1 - )

[0637] [Synthetic Examples 1-2~1-6] Synthesis of Onium Salt Monomers (a-2)~(a-6)

[0638] Using the same synthetic route as that used for the synthesis of the onium salt monomer (a-1) in Synthesis Example 1-1, and appropriately selecting starting materials from aromatic nitriles (SM-a1~a4), styrene derivatives (SM-b1~b4), potassium tert-butoxy alcohols and alcohols (SM-c1~c5), fluoroalcohol derivatives (SM-d1~d3), and sulfonium salts and ferromonite salts (SM-e1~e5), onium salt monomers (a-2)~(a-6) were synthesized. The structural formulas of the synthesized onium salt monomers (a-1)~(a-6) are shown below.

[0639] [Chemistry 172]

[0640]

[0641] [Comparative Synthesis Examples 1-1 to 1-4] Comparative Synthesis of Onium Salt Monomers (Ca-1) to (Ca-4)

[0642] Using the corresponding starting materials and known organic synthesis reactions, comparative onium salt monomers (ca-1) to (ca-4) represented by the following formulas were synthesized. Furthermore, (SM-Ca1) to (SM-Ca4), (SM-Cb1) to (SM-Cb2), and (SM-Cc1) to (SM-Cc4) were used as starting materials.

[0643] [Chemistry 173]

[0644]

[0645] [Chemistry 174]

[0646]

[0647] [Chemistry 175]

[0648]

[0649] [Chemistry 176]

[0650]

[0651] [2] Polymer synthesis

[0652] The monomers used in the synthesis of polymers, other than onium salt monomers (a-1) to (a-6) and comparative onium salt monomers (ca-1) to (ca-4), are described below.

[0653] [Chemistry 177]

[0654]

[0655] [Chemistry 178]

[0656]

[0657] [Chemistry 179]

[0658]

[0659] [Synthetic Example 2-1] Synthesis of Polymer (P-1)

[0660] Under nitrogen atmosphere, a monomer-polymerization initiator solution was prepared by adding 22.2 g of ononium salt monomer (a-1), 21.5 g of monomer (b-1), 6.3 g of monomer (c-1), 2.02 g of V-601, and 70 g of MEK (methyl ethyl ketone) to a flask. In a separate reaction vessel under nitrogen atmosphere, 23 g of MEK was added, and the mixture was heated to 80°C with stirring. The monomer-polymerization initiator solution was then added dropwise over 4 hours. After the addition was complete, the polymerization solution was maintained at 80°C and stirred for 2 hours, then cooled to room temperature. The obtained polymerization solution was added dropwise to 1,500 g of vigorously stirred hexane, and the precipitated polymer was separated by filtration. The obtained polymer was washed twice with 300 g of hexane and then dried under vacuum at 50°C for 20 hours to obtain a white powder polymer (P-1) (yield 48.4 g, 97% yield). The Mw of polymer (P-1) is 8,800, and the Mw / Mn ratio is 1.70. Furthermore, Mw is a converted value for polystyrene obtained using GPC with DMF as a solvent.

[0661] [Chemistry 180]

[0662]

[0663] Synthesis of polymers (P-2 to P-23) and comparative polymers (CP-1) to (CP-8) in [Synthetic Examples 2-2 to 2-23, Comparative Synthetic Examples 2-1 to 2-8]

[0664] By changing the types and blending ratios of the monomers, the polymers shown in Tables 1 and 2 were synthesized using the same method as in Synthesis Example 2-1.

[0665] [Synthetic Example 2-24] Synthesis of Polymer (P-24)

[0666] Polymer (P-24) was synthesized using a polymerization method employing a RAFT agent. Under nitrogen atmosphere, 25.9 g of onium salt monomer (a-4), 18.6 g of monomer (b-1), 5.5 g of monomer (c-1), 1.75 g of V-601, and 70 g of MEK (methyl ethyl ketone) were added to a flask to prepare a monomer-polymerization initiator solution. In a separate reaction vessel under nitrogen atmosphere, 23 g of MEK and 2.63 g of RAFT agent (2-cyano-2-propyldodecyl trithiocarbonate) were added. The mixture was heated to 80°C with stirring, and the monomer-polymerization initiator solution was added dropwise over 4 hours. After the addition was complete, the polymerization solution was maintained at 80°C and stirred for 4 hours. Then, 6.16 g of 1-dodecylthiol, used as an end-treatment agent, was added and stirred for another 3 hours, followed by cooling to room temperature. The resulting polymerization solution was added dropwise to 1,500 g of vigorously stirred hexane, and the precipitated polymer was separated by filtration. The obtained polymer was washed twice with 300g of hexane and then dried under vacuum at 50°C for 20 hours to obtain a white powder polymer (P-24) (yield 50.5g). The Mw of polymer (P-24) was 8,700, and the Mw / Mn ratio was 1.39. Furthermore, Mw was determined using GPC polystyrene conversion with DMF as a solvent.

[0667] [Chemistry 181]

[0668]

[0669] [Table 1]

[0670]

[0671] [Table 2]

[0672]

[0673] [3] Preparation of chemically amplified resist composition

[0674] [Examples 1-1 to 1-24, Comparative Examples 1-1 to 1-8]

[0675] A predetermined composition of polymers (P-1 to P-24), comparative polymers (CP-1 to CP-8), acid generators (PAG-1, PAG-2), and quenchers (SQ-1 to SQ-4) selected from the present invention was dissolved in a solvent containing 0.01% by mass of 3M FC-4430 as a surfactant to prepare a solution. The solution was then filtered through a 0.2 μm Teflon (registered trademark) filter to prepare chemically amplified resist compositions (R-1 to R-24, CR-1 to CR-8).

[0676] [Table 3]

[0677]

[0678] [Table 4]

[0679]

[0680] In Tables 3 and 4, the solvents, quenchers (SQ-1 to SQ-4), and acid generators (PAG-1 and PAG-2) are as described below.

[0681] Solvent: PGMEA (Propylene Glycol Monomethyl Ether Acetate)

[0682] DAA (diacetone alcohol)

[0683] EL (ethyl lactate)

[0684] Quenching agents: SQ-1~SQ-4

[0685] [Chemistry 182]

[0686]

[0687] • Acid generating agents: PAG-1, PAG-2

[0688] [Chemistry 183]

[0689]

[0690] [4] Evaluation of EUV lithography (1)

[0691] [Examples 2-1 to 2-24, Comparative Examples 2-1 to 2-8]

[0692] On a Si substrate with a 20nm thick silicon spin-coating hard mask (SHB-A940, silicon content 43% by mass) manufactured by Shin-Etsu Chemical Industry Co., Ltd., the chemically amplified resist compositions shown in Tables 3 and 4 (R-1~R-24, CR-1~CR-8) were spin-coated. A 50nm thick resist film was fabricated by pre-baking at 100°C for 60 seconds using a hot plate. For the above resist film, an ASML EUV scanning exposure machine NXE3400 (NA 0.33, σ 0.9 / 0.6, dipole illumination) was used, while varying the exposure dose and focus (exposure pitch: 1mJ / cm). 2 LS patterns with a size of 18 nm and a pitch of 36 nm were exposed on the wafer at the focal pitch (0.020 μm). After exposure, PEB was performed for 60 seconds at the temperatures shown in Tables 5 and 6. Subsequently, immersion development was performed for 30 seconds in a 2.38% (w / w) TMAH aqueous solution, followed by rinsing with a surfactant-containing washing material and spin drying to obtain the positive pattern.

[0693] The obtained LS patterns were observed using a critical dimension SEM (CG6300) manufactured by Hitachi High-Tech Corporation, and the sensitivity, EL, LWR, and collapse limit were evaluated according to the following methods. The results are shown in Tables 5 and 6.

[0694] [Sensitivity Evaluation]

[0695] The optimal exposure Eop (mJ / cm) for obtaining an LS pattern with a linewidth of 18nm and a pitch of 36nm was determined. 2 This value is used as the sensitivity. The smaller the value, the higher the sensitivity.

[0696] [EL Review]

[0697] The exposure amount formed within ±10% (16.2~19.8nm) of the 18nm spacing width in the above LS pattern is calculated using the following formula (unit: %). The larger the value, the better the performance.

[0698] EL(%) = (|E1-E2| / Eop) × 100

[0699] E1: Optimal exposure for LS patterns with a linewidth of 16.2nm and a pitch of 36nm.

[0700] E2: Provides optimal exposure for LS patterns with a linewidth of 19.8nm and a pitch of 36nm.

[0701] Eop: Provides optimal exposure for LS patterns with a linewidth of 18nm and a pitch of 36nm.

[0702] [LWR Evaluation]

[0703] The LS pattern obtained by irradiation with Eop is used to measure the dimensions at 10 points along the length of the line. The value of three times the standard deviation (σ) (3σ) of the results is taken as the LWR. The smaller this value is, the more uniform the line width of the pattern with smaller roughness can be obtained.

[0704] [Collapse Limit Assessment of Line Patterns]

[0705] The line dimensions of each exposure at the optimal focal point of the aforementioned LS pattern were measured at 10 points along the length direction. The finest line dimension that could be obtained without collapse was taken as the collapse limit dimension. The smaller the value, the better the collapse limit.

[0706] [Table 5]

[0707]

[0708] [Table 6]

[0709]

[0710] As shown in Tables 5 and 6, the chemically amplified resist compositions using a base polymer comprising repeating units from the onium salt monomers of this invention exhibit good sensitivity and excellent performance in both EL and LWR. Furthermore, a low collapse limit value was confirmed, demonstrating strong resistance to pattern collapse during fine pattern formation. Therefore, the chemically amplified resist compositions of this invention demonstrate suitability as materials for EUV lithography. In particular, compositions incorporating leaving groups show excellent results in terms of sensitivity, collapse limit, and pattern collapse. Moreover, Examples 2-24, which use narrowly dispersed polymers, demonstrate improved performance compared to polymers obtained by conventional polymerization methods.

[0711] [5] Evaluation of EUV lithography (2)

[0712] [Examples 3-1 to 3-24, Comparative Examples 3-1 to 3-8]

[0713] On a Si substrate with a silicon spin-coating hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Industry Co., Ltd., with a film thickness of 20 nm, the chemically amplified resist compositions (R-1~R-24, CR-1~CR-8) shown in Tables 3 and 4 were spin-coated. A 50 nm thick resist film was fabricated by pre-baking at 105°C for 60 seconds using a heated plate. Exposure was then performed using an ASML EUV scanning exposure machine NXE3400 (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, wafer-scale hole pattern with a pitch of 46 nm and a +20% tolerance). PEB was performed for 60 seconds using a heated plate at the temperatures listed in Tables 7 and 8, followed by 30 seconds of development with a 2.38% by mass TMAH aqueous solution, resulting in a hole pattern with a size of 23 nm.

[0714] Using a critical dimension SEM (CG6300) manufactured by Hitachi High-Tech Corporation, the exposure was measured when a hole size of 23 nm was formed, and this amount was used as the sensitivity. In addition, the size of 50 holes at this time was measured, and the dimensional deviation (CDU) was calculated as three times the standard deviation (σ) from the results. The results are shown in Tables 7 and 8.

[0715] [Table 7]

[0716]

[0717] [Table 8]

[0718]

[0719] The results shown in Tables 7 and 8 confirm that the chemically amplified resist composition of the present invention has good sensitivity and excellent CDU. It is evident that, particularly in Examples 3-24, which used narrowly dispersed polymers synthesized via RAFT polymerization, CDU is improved.

[0720] [6] Defect evaluation

[0721] [Examples 4-1 to 4-24, Comparative Examples 4-1 to 4-8]

[0722] The LS pattern with a pitch of 36 nm obtained in the EUV lithography evaluation (1) was observed using a KLA-Tencor KLA2905 bright-field defect inspection system. The number of defects per unit area (defects / cm²) of the pattern was compared. 2 Values ​​above 5.0 are represented by ×, values ​​between 1.0 and 5.0 are represented by △, and values ​​below 1.0 are represented by 〇. Smaller values ​​indicate better performance. The results are shown in Tables 9 and 10.

[0723] [Table 9]

[0724]

[0725] [Table 10]

[0726]

[0727] According to the results shown in Tables 9 and 10, the chemically amplified resist composition of the present invention exhibits the lowest number of pattern defects. In particular, while EUV lithography evaluations of resist compositions CP-4 and CP-8 showed performance equivalent to those of the chemically amplified resist composition of the present invention, their defect evaluations were worse. This is presumably due to the contribution of the acid-leaning groups introduced into the ononium salt monomers used in the synthesis of the polymers contained in the chemically amplified resist composition of the present invention, which improves the defect situation.

[0728] This specification contains the following specifications.

[0729] [1]: An onium salt type monomer, characterized in that it is represented by the following general formula (a);

[0730] [Chemistry 184]

[0731] (a)

[0732] (In the formula, R1 and R4 are each independently a halogen atom, or may contain heteroatoms of a hydrocarbon group with 1 to 20 carbon atoms; R2 is represented by the following general formula (a-1); R3 is represented by the following general formula (a-2); n1 and n2 are each independently 0 or 1; n3 is an integer from 0 to 3; n4, n5, and n6 are each independently integers from 0 to 4; 1 ≤ n4 + n5 ≤ 4 and 1 ≤ n4 + n5 + n6 ≤ 4; L1 is a single bond, ether bond, ester bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond; n7 is an integer from 0 to 4; Q) 1 and Q 2 Each is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; Q 3 and Q 4 Each is independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; Z + It is a iumonium cation.

[0733] [Chemistry 185]

[0734]

[0735] (In the formula, R5 is a halogen atom excluding iodine atoms, or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms; n8 is 0 or 1; n9 is an integer from 0 to 4; and n10 is an integer from 1 to 5, satisfying the relationship 1≤n9+n10≤5.)

[0736] [Chemistry 186]

[0737]

[0738] (where AL) 1 (This is an acid-labile group.)

[0739] [2]: Onium salt type monomers as described in [1] above, wherein the onium salt type monomer is represented by the following general formula (a1);

[0740] [Chemistry 187]

[0741] (a1)

[0742] (where n3~n7, R1~R4, L1, Q) 1 Q 2 and Z + Same as above.

[0743] [3]: As described in [1] or [2] above, the Z... + It is a sulfonium cation represented by the following general formula (cation-1) or a monazine cation represented by the following general formula (cation-2);

[0744] [Chemistry 188]

[0745]

[0746] (where R is in the formula) ct1 ~R ct5 Each is an independent hydrocarbon group with 1 to 30 carbon atoms, which may also contain heteroatoms; in addition, R ct1 and R ct2 They can also bond with each other to form rings with the sulfur atoms they are bonded to.

[0747] [4]: A polymer comprising repeating units of onium salt monomers from any one of [1] to [3] above.

[0748] [5]: The polymer as described in [4] above, wherein the polymer further comprises repeating units represented by the following general formula (b1) or (b2);

[0749] [Chemistry 189]

[0750]

[0751] (where R is in the formula) A Each can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group;

[0752] X1 Single bond, phenylene, naphthylene, *-C(=O)-OX 11 -、or *-C(=O)-NH-X 11 - The phenylene and naphthylene groups can also be substituted by alkoxy or halogen atoms with 1 to 10 carbon atoms, which may also contain fluorine atoms; X 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms. The above-mentioned saturated hydrocarbon group may also contain hydroxyl groups, ether bonds, ester bonds, or lactone rings.

[0753] X 2 It is a single bond, *-C(=O)-O-, or *-C(=O)-NH-;

[0754] * indicates an atomic bond with a carbon atom in the main chain;

[0755] AL 2 and AL 3 Each is an independent acid-labile group;

[0756] R 11 It may contain halogen atoms, cyano, hydroxyl, nitro, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl oxy group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms.

[0757] (where a is an integer between 0 and 4.)

[0758] [6]: The polymers described above [4] or [5], wherein the polymer further comprises repeating units represented by the following general formula (c1);

[0759] [Chemistry 190]

[0760]

[0761] (where R is in the formula) A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group;

[0762] Y 1 It represents a single bond, *-C(=O)-O-, or *-C(=O)-NH-; * indicates an atomic bond with a carbon atom in the main chain;

[0763] R 21 It can be a halogen atom, nitro, cyano, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon carbonyl oxy group with 2 to 20 carbon atoms containing heteroatoms;

[0764] c is an integer from 1 to 4; d is an integer from 0 to 3; however, 1 ≤ c + d ≤ 5.

[0765] [7]: The polymer of any one of [4] to [6] above, wherein the polymer further comprises a repeating unit represented by the following general formula (d1);

[0766] [Chemistry 191]

[0767]

[0768] (where R is in the formula) A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group;

[0769] Z 1 Single bond, phenylene, naphthylene, *-C(=O)-OZ 11 -、or *-C(=O)-NH-Z 11 - The phenylene and naphthylene groups can also be substituted by alkoxy or halogen atoms with 1 to 10 carbon atoms, which may also contain fluorine atoms; * indicates an atomic bond with a carbon atom in the main chain; Z 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms. The saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring.

[0770] R 31 It is a hydrogen atom, or a group having 1 to 20 carbon atoms containing at least one of the following structures: hydroxyl group (other than phenolic hydroxyl), cyano group, carbonyl group, carboxyl group, ether bond, ester bond, sulfonate bond, carbonate bond, lactone ring, sulopentalide ring, and carboxylic anhydride (-C(=O)-OC(=O)-).

[0771] [8]: A chemically amplified resist composition comprising (A) a base polymer comprising any one of the polymers described above [4] to [7].

[0772] [9]: The chemically amplified resist composition as described in [8] above, wherein the chemically amplified resist composition further contains one or more selected from (B) organic solvents, (C) quenchers, (D) acid generators, (E) surfactants, and (F) dissolution inhibitors.

[0773]

[10] : A pattern forming method comprising the steps of forming a resist film on a substrate using a chemically amplified resist composition as described in [8] or [9] above, exposing the resist film to high-energy rays, and developing the exposed resist film using a developer.

[0774]

[11] : The pattern forming method described in

[10] above, wherein the 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.

[0775] Furthermore, the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and those having substantially the same structure and performing the same effects as the technical concepts described in the claims of the present invention are all included within the technical scope of the present invention.

Claims

1. A onium salt type monomer, characterized in that, It is represented by the following general formula (a); (a) In the formula, R1 and R4 are each independently a halogen atom, or may contain heteroatoms and have 1 to 20 carbon atoms in a hydrocarbon group; R2 is represented by the following general formula (a-1), and R3 is represented by the following general formula (a-2); n1 and n2 are each independently 0 or 1; n3 is an integer from 0 to 3; n4, n5, and n6 are each independently an integer from 0 to 4, 1 ≤ n4 + n5 ≤ 4 and 1 ≤ n4 + n5 + n6 ≤ 4; L1 is a single bond, ether bond, ester bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond; n7 is an integer from 0 to 4, Q 1 and Q 2 Each is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; Q 3 and Q 4 Each is independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; Z + It is a ium cation; In the formula, R5 is a halogen atom excluding iodine atoms, or a hydrocarbon group with 1 to 20 carbon atoms that may contain heteroatoms; n8 is 0 or 1; n9 is an integer from 0 to 4; and n10 is an integer from 1 to 5, which conforms to the relationship 1≤n9+n10≤5. In the formula, AL 1 It is an acid-labile group.

2. The onium salt type monomer according to claim 1, wherein, The onium salt type monomer is represented by the following general formula (a1); (a1) In the formula, n3~n7, R1~R4, L1, Q 1 Q 2 and Z + Same as above.

3. The onium salt type monomer according to claim 1, wherein, The Z + It is a sulfonium cation represented by the following general formula (cation-1) or a monazine cation represented by the following general formula (cation-2); In the formula, R ct1 ~R ct5 Each is an independent hydrocarbon group with 1 to 30 carbon atoms, which may also contain heteroatoms; in addition, R ct1 and R ct2 They can also bond with each other to form a ring together with the sulfur atoms they are bonded to.

4. A polymer comprising repeating units derived from an onium salt monomer according to any one of claims 1 to 3.

5. The polymer according to claim 4, wherein, The polymer also contains repeating units represented by the following general formula (b1) or (b2); In the formula, R A Each can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; X 1 Single bond, phenylene, naphthylene, *-C(=O)-OX 11 -、or *-C(=O)-NH-X 11 - The phenylene and naphthylene groups can also be substituted by alkoxy or halogen atoms with 1 to 10 carbon atoms, which may also contain fluorine atoms; X 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms. The above-mentioned saturated hydrocarbon group may also contain hydroxyl groups, ether bonds, ester bonds, or lactone rings. X 2 It is a single bond, *-C(=O)-O-, or *-C(=O)-NH-; * indicates an atomic bond with a carbon atom in the main chain; AL 2 and AL 3 Each is an independent acid-labile group; R 11 It may contain halogen atoms, cyano, hydroxyl, nitro, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl oxy group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxy carbonyl group with 2 to 20 carbon atoms containing heteroatoms. a is an integer between 0 and 4.

6. The polymer according to claim 4, wherein, The polymer also contains repeating units represented by the following general formula (c1); In the formula, R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; Y 1 It represents a single bond, *-C(=O)-O-, or *-C(=O)-NH-; * indicates an atomic bond with a carbon atom in the main chain; R 21 It can be a halogen atom, nitro, cyano, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxy group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon carbonyl oxy group with 2 to 20 carbon atoms containing heteroatoms; c is an integer from 1 to 4; d is an integer from 0 to 3; however, 1 ≤ c + d ≤ 5.

7. The polymer according to claim 4, wherein, The polymer also contains repeating units represented by the following general formula (d1); In the formula, R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; Z 1 Single bond, phenylene, naphthylene, *-C(=O)-OZ 11 -、or *-C(=O)-NH-Z 11 - The phenylene and naphthylene groups can also be substituted by alkoxy or halogen atoms with 1 to 10 carbon atoms, which may also contain fluorine atoms; * indicates an atomic bond with a carbon atom in the main chain; Z 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms. The saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or an lactone ring. R 31 It is a hydrogen atom, or a group having 1 to 20 carbon atoms that contains at least one of the following structures: hydroxyl group (other than phenolic hydroxyl group), cyano group, carbonyl group, carboxyl group, ether bond, ester bond, sulfonate bond, carbonate bond, lactone ring, sulcinolone ring, and carboxylic anhydride (-C(=O)-OC(=O)-).

8. A chemically amplified resist composition comprising (A) a base polymer comprising the polymer according to claim 4.

9. The chemically amplified resist composition according to claim 8, wherein, The chemically amplified resist composition also contains one or more selected from (B) organic solvents, (C) quenchers, (D) acid generators, (E) surfactants, and (F) dissolution inhibitors.

10. A method for forming a pattern, comprising the following steps: A resist film is formed on a substrate using the chemically amplified resist composition according to claim 8. The resist film was exposed to high-energy rays, and The exposed resist film was developed using a developer.

11. The pattern forming method according to claim 10, wherein, The high-energy rays used are ArF excimer lasers with a wavelength of 193 nm, KrF excimer lasers with a wavelength of 248 nm, electron beams, or extreme ultraviolet light with a wavelength of 3 to 15 nm.

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