Onium salt type monomers, polymers, chemically amplified resist compositions and patterning methods

Abstract

This invention relates to onium salt monomers, polymers, chemically amplified resist compositions, and patterning methods. The objective of this invention is to provide onium salt monomers for use in chemically amplified resist compositions that exhibit excellent solubility in organic solvents, high sensitivity, high contrast, excellent EL, LWR, CDU, etc., strong resistance to pattern collapse during fine pattern formation, and excellent etching resistance. The solution to this objective is an onium salt monomer represented by formula (a). R1 ​​is a halogen atom or a hydrocarbon group. R2 and R3 are hydrogen atoms or fluorine atoms. n1 is 0-3, n2 is 1-4, and n3 is 0-4. L1 is a single bond, ether bond, ester bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond. Q1 and Q2 are hydrogen atoms, fluorine atoms, or fluorinated saturated hydrocarbon groups. Q3 and Q4 are fluorine atoms or fluorinated saturated hydrocarbon groups. + It is a ium cation.

Description

Technical Field

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

[0002] With the increasing integration and speed of LSI (Light Detector System), the miniaturization of patterning is also progressing rapidly. In particular, the expansion of the flash memory market and the increase in memory capacity are driving this miniaturization. Regarding the most advanced miniaturization technologies, mass production of 65nm node devices using ArF lithography is already underway, and preparations are underway for mass production of 45nm node devices using next-generation ArF immersion lithography. For next-generation 32nm node devices, options being explored include immersion lithography using an ultra-high nanometer (NA) lens (combining a liquid with a higher refractive index than water with a high-refractive-index lens and a high-refractive-index resist film), extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm, and ArF lithography with only double exposure (double patterning lithography).

[0003] As miniaturization progresses and the light diffraction limit approaches, the contrast of the light gradually decreases. This decrease in contrast leads to a reduction in the resolution or focal latitude of the hole and groove patterns within the positive resist film.

[0004] As patterns become more refined, edge roughness (LWR) of the line pattern and dimensional uniformity (CDU) of the hole pattern become problematic. Issues cited include uneven distribution of the base polymer and acid generator, the effects of aggregation, and acid diffusion. Furthermore, the thinning of the resist film tends to increase LWR, and the resulting deterioration of LWR due to thinning during refinement becomes a serious problem.

[0005] In EUV lithography resist compositions, high sensitivity, high resolution, and low light-to-weight ratio (LWR) must be achieved simultaneously. Shortening the acid diffusion distance will reduce LWR, but it will also lower sensitivity. For example, lowering the post-exposure baking (PEB) temperature will reduce LWR, but it will also lower sensitivity. A trade-off between sensitivity and LWR needs to be struck.

[0006] To suppress acid diffusion, resist compounds containing repeating units from onium salts of sulfonic acids with polymerizable unsaturated bonds have been proposed (Patent Document 1). Such so-called polymer-bonded acid generators, due to the generation of polymeric sulfonic acids upon exposure, exhibit a very short acid diffusion distance. Furthermore, sensitivity can be improved by increasing the ratio of the acid generator. Additive acid generators, while increasing the amount added, also increase sensitivity, but this also increases the acid diffusion distance. Since acid diffuses unevenly, increased acid diffusion degrades LWR and CDU. In terms of balancing sensitivity, LWR, and CDU, polymeric acid generators offer superior performance.

[0007] Iodine atoms exhibit very high absorption at EUV wavelengths of 13.5 nm, leading to the observed generation of secondary electrons during exposure, which has attracted attention in EUV lithography. Patent Document 2 describes a photoacid generator in which iodine atoms are introduced into the anion, and Patent Document 3 describes a photoacid generator containing polymerizable groups and iodine atoms in the anion. While this has resulted in some improvement in lithography performance, concerns remain regarding reduced solubility in organic solvents due to the introduction of iodine atoms, as well as potential precipitation in solvents. Therefore, improvements in workability are desired.

[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 with higher sensitivity and improved line leaching resistance (LWR) and hole diameter (CDU) in chemically amplified resist compositions using acid as a catalyst, while also exhibiting excellent etch resistance after patterning. Furthermore, the development of monomers or polymers with excellent solvent solubility is desired to expand process tolerance during manufacturing.

[0015] The present invention was made in view of the foregoing circumstances, and aims to provide a chemically amplified resist composition that exhibits excellent solubility in organic solvents, high sensitivity, excellent lithographic performance such as exposure latitude (EL), LWR, and CDU, strong resistance to pattern collapse during micro-pattern formation, and excellent etching resistance in optical lithography using high-energy rays, including an onium salt monomer, 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 represented by the following formula (a).

[0018] [Chemistry 1]

[0019]

[0020] In the formula, R1 is a halogen atom other than iodine, a cyano group, a nitro group, or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms. R2 and R3 are hydrogen atoms or fluorine atoms, respectively. n1 is an integer from 0 to 3, n2 is an integer from 1 to 4, and n3 is an integer from 0 to 4. L1 is a single bond, ether bond, ester bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond. Q1 and Q2 are independently hydrogen atoms, saturated hydrocarbon groups with 1 to 6 carbon atoms, fluorine atoms, or fluorinated saturated hydrocarbon groups with 1 to 6 carbon atoms, respectively. Q3 and Q4 are independently hydrogen atoms, saturated hydrocarbon groups with 1 to 6 carbon atoms, fluorine atoms, or fluorinated saturated hydrocarbon groups with 1 to 6 carbon atoms, respectively. Z + It is a ium cation.

[0021] Such onium salt monomers would be ideal for use in optical lithography, especially in applications using high-energy rays such as KrF excimer lasers, ArF excimer lasers, electron beams (EB), and EUV. These monomers exhibit excellent solubility in organic solvents, high sensitivity, high contrast, and excellent lithography performance, including excellent exposure latitude (EL), LWR, and CDU. Furthermore, they demonstrate strong resistance to pattern collapse during the formation of fine patterns and excellent etching resistance.

[0022] Furthermore, the onium salt type monomer of the present invention is preferably represented by the following formula (a1).

[0023] [Chemistry 2]

[0024]

[0025] In the formula, n1~n3, R1, L1, Q1~Q4 and Z + Same as above.

[0026] At this point, it is preferable that the onium salt type monomer of the present invention is represented by the following formula (a2).

[0027] [Chemistry 3]

[0028]

[0029] In the formula, n1~n3, R1, Q1, Q2 and Z + Same as above.

[0030] If this is the case, the effects of the present invention can be more fully realized.

[0031] Also, Z + The sulfonium cation represented by formula (cation-1) or the monazine cation represented by formula (cation-2) is more ideal.

[0032] [Chemistry 4]

[0033]

[0034] In the formula, R ct1 ~R ct5 Each group is a hydrocarbon group with 1 to 30 carbon atoms, which may be independently composed of halogen atoms or may also contain heteroatoms. Also, R ct1 and R ct2 They can also bond to each other and form rings together with the sulfur atoms they are bonded to.

[0035] If the cationic portion is in this manner, the effects of the present invention can be more fully realized.

[0036] Furthermore, the present invention provides a polymer containing repeating units derived from the above-mentioned onium salt monomer.

[0037] The polymer of the present invention functions as a photoacid generator in a chemically amplified resist composition and also functions as a base polymer. It provides a chemically amplified resist composition that exhibits excellent solubility in organic solvents, high sensitivity, high contrast, and excellent lithographic performance such as exposure latitude (EL), LWR, and CDU, especially in optical lithography using high-energy rays such as KrF excimer lasers, ArF excimer lasers, electron beams (EB), and EUV. It also has strong resistance to pattern collapse during the formation of fine patterns and excellent etching resistance.

[0038] In addition, the polymers of the present invention may also contain repeating units represented by formula (b1) or (b2).

[0039] [Chemistry 5]

[0040]

[0041] In the formula, R AEach can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0042] X 1 Single bond, phenylene, naphthylene, *-C(=O)-OX 11 -or *-C(=O)-NH-X 11 - and the phenylene or naphthylene group can also be substituted by an alkoxy or halogen atom with 1 to 10 carbon atoms, which may also contain a fluorine atom. X 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms, and the saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or an lactone ring.

[0043] X 2 It is a single bond, *-C(=O)-O- or *-C(=O)-NH-.

[0044] * indicates an atomic bond with a carbon atom in the main chain.

[0045] AL 1 and AL 2 Each is an acid-labile group.

[0046] R 11 It can be a halogen atom, a cyano group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxygen 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 oxygen group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms containing heteroatoms.

[0047] a is an integer between 0 and 4.

[0048] Furthermore, the polymer of the present invention may also contain repeating units represented by the following formula (c1).

[0049] [Chemistry 6]

[0050]

[0051] In the formula, R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0052] 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.

[0053] R 21It can be a halogen atom, nitro group, cyano group, or a hydrocarbon 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 group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms.

[0054] c is an integer from 1 to 4. d is an integer from 0 to 3. However, 1 ≤ c + d ≤ 5.

[0055] In addition, the polymer of the present invention may also contain repeating units represented by the following formula (d1).

[0056] [Chemistry 7]

[0057]

[0058] In the formula, R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0059] Z 1 Single bond, phenylene, naphthylene, *-C(=O)-OZ 11 -or *-C(=O)-NH-Z 11 - or the phenylene or naphthylene group may be substituted by an alkoxy or halogen atom with 1 to 10 carbon atoms, which may also contain a fluorine atom. * indicates an atomic bond with the carbon atom of the main chain. Z 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms, and the saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or an lactone ring.

[0060] R 31 It is a hydrogen atom, or a group containing at least one of the following structures with 1 to 20 carbon atoms: hydroxyl group (other than phenolic hydroxyl 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)-).

[0061] The polymers of the present invention copolymerize various repeating units, thereby imparting the necessary properties according to the purpose.

[0062] Furthermore, the present invention provides a chemically amplified resist composition comprising (A) a base polymer comprising the above-mentioned polymer.

[0063] The chemically amplified resist composition of the present invention exhibits excellent solubility in organic solvents, particularly in optical lithography using high-energy rays such as KrF excimer lasers, ArF excimer lasers, electron beams (EB), and EUV. It also provides high sensitivity, high contrast, excellent lithography performance such as exposure latitude (EL), LWR, and CDU, strong resistance to pattern collapse during the formation of fine patterns, and excellent etching resistance.

[0064] Furthermore, the chemically amplified resist composition of the present invention may contain one or more of (B) an organic solvent, (C) a quencher, (D) an acid generator, (E) a surfactant, and (F) a dissolution inhibitor.

[0065] The chemically amplified resist composition of the present invention, by containing various components, can impart the necessary properties according to the purpose.

[0066] Furthermore, the present invention provides a pattern forming method, comprising the following steps:

[0067] A resist film is formed on a substrate using the above-described chemically amplified resist composition.

[0068] The aforementioned resist film was exposed to high-energy rays, and

[0069] The previously exposed resist film was developed using a developer.

[0070] The pattern forming method of the present invention can effectively form fine patterns by using the chemically amplified resist composition of the present invention.

[0071] Furthermore, the aforementioned high-energy rays should preferably be ArF excimer lasers with a wavelength of 193 nm or KrF excimer lasers with a wavelength of 248 nm, electron beams, or extreme ultraviolet rays with a wavelength of 3-15 nm.

[0072] The pattern forming method of the present invention can ideally utilize such high-energy rays.

[0073] [The effects of the invention]

[0074] A resist film containing a polymer comprising repeating units derived from onium salt monomers represented by formula (a) exhibits good organic solvent solubility due to the fluorine substituents on the styrene structure, while also possessing low acid diffusion due to the large atomic weight of iodine atoms. This prevents resolution degradation caused by acid diffusion blurring and improves LWR and CDU. Furthermore, EUV at a wavelength of 13.5 nm is highly absorbed by iodine atoms, resulting in the generation of secondary electrons from iodine atoms during exposure and enhancing sensitivity. This allows for the construction of a chemically amplified resist composition with high sensitivity and improved LWR and CDU. Additionally, the aromatic ring acts as a good etching-resistant group, making it ideal for fine pattern formation. Detailed Implementation

[0075] As described above, there is a requirement to develop a chemically amplified resist composition that exhibits excellent solubility in organic solvents, high sensitivity and contrast, excellent lithographic performance such as exposure latitude (EL), LWR, and CDU, and strong resistance to pattern collapse and etching during the formation of fine patterns, especially in optical lithography using high-energy rays such as KrF excimer lasers, ArF excimer lasers, electron beams (EB), and EUV. This composition includes: an onium salt monomer, a polymer containing repeating units from the onium salt monomer, a chemically amplified resist composition containing the polymer, and a patterning method using the chemically amplified resist composition.

[0076] Through repeated and in-depth exploration in order to achieve the aforementioned objectives, the inventors discovered that by using a polymer containing repeating units of a fluorosulfonic acid anion with a styrene structure having fluorine-substituent polymerizable groups and an aromatic ring structure substituted with iodine atoms as a polymer-bonded acid generator, a chemically amplified resist composition with excellent solubility in organic solvents, high sensitivity, improved LWR and CDU, high contrast and high resolution, and excellent etching resistance can be obtained, thus completing the present invention.

[0077] That is, the present invention is an onium salt type monomer, which is represented by the following formula (a).

[0078] [Chemistry 8]

[0079]

[0080] In the formula, R1 is a halogen atom other than iodine, a cyano group, a nitro group, or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms. R2 and R3 are hydrogen atoms or fluorine atoms, respectively. n1 is an integer from 0 to 3, n2 is an integer from 1 to 4, and n3 is an integer from 0 to 4. L1 is a single bond, ether bond, ester bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond. Q1 and Q2 are independently hydrogen atoms, saturated hydrocarbon groups with 1 to 6 carbon atoms, fluorine atoms, or fluorinated saturated hydrocarbon groups with 1 to 6 carbon atoms, respectively. Q3 and Q4 are independently hydrogen atoms, saturated hydrocarbon groups with 1 to 6 carbon atoms, fluorine atoms, or fluorinated saturated hydrocarbon groups with 1 to 6 carbon atoms, respectively. Z + It is a ium cation.

[0081] The present invention will now be described in detail, but it is not limited thereto.

[0082] [Onium salt type monomer]

[0083] The onium salt type monomer of the present invention is represented by the following formula (a).

[0084] [Chemistry 9]

[0085]

[0086] In the formula, R1 is a halogen atom other than iodine, a cyano group, a nitro group, or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms. R2 and R3 are hydrogen atoms or fluorine atoms, respectively. n1 is an integer from 0 to 3, n2 is an integer from 1 to 4, and n3 is an integer from 0 to 4. L1 is a single bond, ether bond, ester bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond. Q1 and Q2 are independently hydrogen atoms, saturated hydrocarbon groups with 1 to 6 carbon atoms, fluorine atoms, or fluorinated saturated hydrocarbon groups with 1 to 6 carbon atoms, respectively. Q3 and Q4 are independently hydrogen atoms, saturated hydrocarbon groups with 1 to 6 carbon atoms, fluorine atoms, or fluorinated saturated hydrocarbon groups with 1 to 6 carbon atoms, respectively. Z + It is a ium cation.

[0087] In formula (a1), n1 is an integer from 0 to 3. Considering the availability of raw materials, n1 should preferably be 0 or 1, with 0 being even better. n2 is an integer from 1 to 4, preferably 1 or 2, with 1 being even better, considering the availability of raw materials. The more iodine atoms in the anionic structure, the higher the absorption, especially for EUV, but the solvent solubility will be reduced, and there is a concern about precipitation in the resist composition. Therefore, n2 should be controlled within an appropriate range. n3 is an integer from 0 to 4, preferably 0, 1, 2, or 3, with 1 being even better.

[0088] In formula (a), the styrene structure with fluorine substituents, which is linked by an ether bond between the aromatic ring containing an iodine atom as a substituent, is preferably bonded to the position adjacent to the carbon atom bonded by L1. By setting this positional relationship, the steric hindrance loosens the condensed structure of the molecules, thus breaking the trade-off between the deterioration of solvent solubility caused by the introduction of the iodine atom. Furthermore, the introduction of the styrene structure by the ether bond can also be expected to improve heat resistance. In addition, the effect of the fluorine substituent can also be expected to impart solvent solubility, while the presence of a large number of fluorine atoms can improve the sensitivity of EUV.

[0089] In formula (a), R1 is a halogen atom other than iodine, a cyano group, a nitro group, or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms. The aforementioned halogen atom is a fluorine atom, a chlorine atom, or a bromine atom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include: alkyl groups with 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecanyl, octadecyl, nonadecanyl, and eicosyl; cyclic saturated hydrocarbon groups with 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norcamphenyl, and adamantyl; alkenyl groups with 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups with 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups with 6 to 20 carbon atoms, such as phenyl and naphthyl; aralkyl groups with 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups 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, sulfur, nitrogen, and halogen atoms, and a portion of the -CH2- group in the aforementioned hydrocarbon group can also be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, the group may contain hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulfonate ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl, etc. When n1 is 2 or 3, each R1 can be the same or different.

[0090] Furthermore, when n1 is 2 or 3, multiple R1s can also bond to each other and form a ring together with the carbon atoms of the aromatic rings they are bonded to. Specific examples of the rings formed in this case include: cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornene rings, adamantane rings, etc. Also, some or all of the hydrogen atoms in the aforementioned rings can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms, and some of the -CH2- in the aforementioned rings can also be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. The result can also include 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.

[0091] In 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 ester bond is even more preferred.

[0092] In equation (a), Q 1 and Q 2Each of the following can be independently composed of a hydrogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. The fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms is preferably trifluoromethyl.

[0093] In equation (a), Q 3 and Q 4 Each of the following can be independently composed of a hydrogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. The fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms is preferably trifluoromethyl. Q 3 and Q 4 It would be even better if it were fluorine atoms.

[0094] In equation (a), -[C(Q1)(Q2)] n3 -C(Q3)(Q4)-SO3 - Specific examples of the partial structures shown are preferably as shown below, but are not limited to these. Additionally, in the following formula, * denotes the atomic bond with L1.

[0095] [Chemistry 10]

[0096]

[0097] Among them, Acid-1 to Acid-7 are preferred, with Acid-1 to Acid-3, Acid-6 and Acid-7 being even better.

[0098] The onium salt type monomer represented by formula (a) should preferably be represented by the following formula (a1).

[0099] [Chemistry 11]

[0100]

[0101] In the formula, n1~n3, R1, L1, Q1~Q4 and Z + Same as above.

[0102] As mentioned above, if all the substituents on the aromatic ring of the styrene site are fluorine substituents, it is expected that not only will the availability of raw materials and solvent solubility be improved, but also performance improvements such as sensitivity during EUV exposure and suppression of foreign matter adhesion during development can be expected by introducing a large number of fluorine atoms. Furthermore, by improving the solvent solubility of the monomer, it is expected that the residual monomer during polymer synthesis will be reduced, the solvent solubility of the polymer itself will be improved, and a significant reduction in defects such as slag, which can be a problem during photolithography, can also be expected.

[0103] The onium salt type monomer represented by formula (a) is preferably represented by formula (a2).

[0104] [Chemistry 12]

[0105]

[0106] In the formula, n1~n3, R1, Q1, Q2 and Z + Same as above.

[0107] As mentioned above, it is more ideal from the perspective of obtaining raw materials if the bonding structure between the anionic site and the aromatic ring site with iodine as a substituent is an ester bond. As shown in the following general formula, it is even better if the ester bond connecting the aromatic ring site with iodine as a substituent and the anionic site, and the ether bond connecting the fluorostyrene site with fluorine as a substituent, are adjacent on the aromatic ring; that is, if the ether bond is ortho-positioned relative to the carbon atom bonded to the ester, then solubility can be further improved by utilizing the steric hindrance between the aromatic rings.

[0108] [Chemistry 13]

[0109]

[0110] Specific examples of the anions of onium salt type monomers represented by formula (a) are shown below, but are not limited thereto. In addition, in the following formula, R2 and R3 are hydrogen atoms and / or fluorine atoms, Q1 is the same as described above, and the bonding positions of various substituents on the aromatic ring can also be interchanged.

[0111] [Chemistry 14]

[0112]

[0113] [Chemistry 15]

[0114]

[0115] [Chemistry 16]

[0116]

[0117] [Chemistry 17]

[0118]

[0119] [Chemistry 18]

[0120]

[0121] [Chemistry 19]

[0122]

[0123] [Chemistry 20]

[0124]

[0125] [Chemistry 21]

[0126]

[0127] [Chemistry 22]

[0128]

[0129] [Chemistry 23]

[0130]

[0131] [Chemistry 24]

[0132]

[0133] [Chemistry 25]

[0134]

[0135] [Chemistry 26]

[0136]

[0137] [Chemistry 27]

[0138]

[0139] In equation (a), Z + The aforementioned onium cation is preferably a sulfonium cation represented by the following formula (cation-1) or a sulfonium cation represented by the following formula (cation-2).

[0140] [Chemistry 28]

[0141]

[0142] In equations (cation-1) and (cation-2), R ct1 ~R ct5 Each is a hydrocarbon group with 1 to 30 carbon atoms, which may be independently composed of halogen atoms or may contain heteroatoms.

[0143] R ct1 ~R ct5 Specific examples of halogen atoms that can be represented include: fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.

[0144] 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, norcamphenyl, 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 groups, which should preferably be aryl. 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, and some of the -CH2- 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, sulfonolactone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0145] Also, R ct1 and R ct2 They can also bond to each other and form rings together with the sulfur atoms they are bonded to. Specific examples of the aforementioned ring structures can be shown in the following formulas, etc.

[0146] [Chemistry 29]

[0147]

[0148] In the formula, the dashed line represents R. ct3 Atomic bonds.

[0149] Specific examples of sulfonium cations represented by formula (cation-1) are listed below, but are not limited thereto.

[0150] [Chemistry 30]

[0151]

[0152] [Chemistry 31]

[0153]

[0154] [Chemistry 32]

[0155]

[0156] [Chemistry 33]

[0157]

[0158] [Chemistry 34]

[0159]

[0160] [Chemistry 35]

[0161]

[0162] [Chemistry 36]

[0163]

[0164] [Chemistry 37]

[0165]

[0166] [Chemistry 38]

[0167]

[0168] [Chemistry 39]

[0169]

[0170] [Chemistry 40]

[0171]

[0172] [Chemistry 41]

[0173]

[0174] [Chemistry 42]

[0175]

[0176] [Chemistry 43]

[0177]

[0178] [Chemistry 44]

[0179]

[0180] [Chemistry 45]

[0181]

[0182] [Chemistry 46]

[0183]

[0184] [Chemistry 47]

[0185]

[0186] [Chemistry 48]

[0187]

[0188] [Chemistry 49]

[0189]

[0190] [Transformation 50]

[0191]

[0192] [Chemistry 51]

[0193]

[0194] [Chemistry 52]

[0195]

[0196] [Chemistry 53]

[0197]

[0198] [Chemistry 54]

[0199]

[0200] [Chemistry 55]

[0201]

[0202] [Chemistry 56]

[0203]

[0204] Specific examples of citric cations represented by formula (cation-2) are listed below, but are not limited thereto.

[0205] [Chemistry 57]

[0206]

[0207] [Chem.58]

[0208]

[0209] Specific examples of onium salt type monomers represented by formula (a) can be listed by any combination of the aforementioned anions and cations.

[0210] The onium salt type monomer represented by formula (a) can be synthesized, for example, using the same method as the sulfonium salt with polymerizable anion described in Japanese Patent No. 5201363, but is not limited thereto.

[0211] [polymer]

[0212] The polymer of the present invention contains repeating units (hereinafter also referred to as repeating unit a) derived from the onium salt type monomer represented by formula (a).

[0213] The polymer of this invention functions as both a photoacid generator and a base polymer in chemically amplified photoresist compositions. Structural features of the polymer include repeating units having a benzene or naphthalene structure and an onium salt structure. This benzene or naphthalene structure is a benzene or naphthalene structure directly bonded to the main chain from the onium salt monomer of this invention. This onium salt structure contains a fluorosulfonic acid anion with an aromatic ring structure substituted with an iodine atom. Iodine atoms have extremely high absorption at EUV wavelengths of 13.5 nm, thus generating secondary electrons upon exposure. The energy of these secondary electrons, by moving to the acid generator, promotes its decomposition, thereby increasing sensitivity. The polymeric groups composed of styrene structures are more rigid than polymeric groups such as methacrylates, and improve the polymer's glass transition temperature (Tg). It is believed that aromatic rings within or between the base polymers, through interactions (π-π stacking effect), result in a regular arrangement of the base polymers, exhibiting resistance to pattern collapse even during micro-pattern formation. Furthermore, even in the etching step after micro-pattern formation, the aromatic rings directly bonded to the main chain maintain excellent etching resistance. In iodine-substituted aromatic rings, the iodine atom preferably substitutes for the carbon atom adjacent to the polymerizable group, thereby suppressing the rotation of the bonding axes between the aromatic ring of the polymerizable group and the iodine-substituted aromatic ring. Therefore, excessive acid diffusion can be suppressed, and excellent line patterning (LWR) and hole patterning (CDU) can be formed, resulting in patterns with strong resistance to pattern collapse. This makes it particularly ideal as a material for chemically amplified positive resist compositions. In addition, the fluorine substituents introduced onto the aromatic rings at the styrene sites are expected to improve solvent solubility, and the inherent EUV absorption of fluorine itself also suggests improved sensitivity. The onium salt type monomer of the present invention is expected to improve the solvent solubility of the polymer itself during polymerization, and is also expected to prevent defects not only caused by solvent solubility, but also the adhesion of the pattern after the resist is developed due to the appropriate water repellency effect brought about by the effect of fluorine substituent.

[0214] The aforementioned polymer may also contain repeating units represented by formula (b1) (hereinafter also referred to as repeating unit b1) or repeating units represented by formula (b2) (hereinafter also referred to as repeating unit b2).

[0215] [Chemistry 59]

[0216]

[0217] In the formula, RA Each can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0218] X 1 Single bond, phenylene, naphthylene, *-C(=O)-OX 11 -or *-C(=O)-NH-X 11 - and the phenylene or naphthylene group can also be substituted by an alkoxy or halogen atom with 1 to 10 carbon atoms, which may also contain a fluorine atom. X 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms, and the saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or an lactone ring.

[0219] X 2 It is a single bond, *-C(=O)-O- or *-C(=O)-NH-.

[0220] * indicates an atomic bond with a carbon atom in the main chain.

[0221] AL 1 and AL 2 Each is an acid-labile group.

[0222] R 11 It can be a halogen atom, a cyano group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxygen 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 oxygen group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms containing heteroatoms.

[0223] a is an integer between 0 and 4.

[0224] In equations (b1) and (b2), R A Each can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0225] In equation (b1), X 1 Single bond, phenylene, naphthylene, *-C(=O)-OX 11 -or *-C(=O)-NH-X 11 - and the phenylene or naphthylene group can also be substituted by an alkoxy or halogen atom with 1 to 10 carbon atoms, which may also contain a fluorine atom. X 11 It is a saturated alkylene group, phenylene group, or naphthylene group having 1 to 10 carbon atoms, and the saturated alkylene group may also contain a hydroxyl group, ether bond, ester bond, or lactone ring. * indicates an atomic bond with a carbon atom in the main chain.

[0226] In equation (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 11It can be a halogen atom, a cyano group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon oxygen group with 1 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms, a hydrocarbon carbonyl oxygen group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms containing heteroatoms. 'a' is an integer from 0 to 4, preferably 0 or 1.

[0227] In equations (b1) and (b2), AL 1 and AL 2 Each of these groups is an acid-indestructible group independently. Specific examples of the aforementioned acid-indestructible groups can be cited, for example, those described in Japanese Patent Application Publication No. 2013-80033 and Japanese Patent Application Publication No. 2013-83821, but are not limited thereto.

[0228] For representativeness, specific examples of the aforementioned acid-instable groups can be listed as those represented by formulas (AL-1) to (AL-3).

[0229] [Transformation 60]

[0230]

[0231] In the formula, * represents an atomic bond.

[0232] In equations (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. The aforementioned hydrocarbon groups can be linear, branched, or cyclic. Preferably, the aforementioned hydrocarbon groups have 1 to 20 carbon atoms.

[0233] In equation (AL-1), b is an integer from 0 to 10, preferably an integer from 1 to 5.

[0234] In equation (AL-2), R L3 and R L4 Each group is independently composed of 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. The aforementioned hydrocarbon groups can be linear, branched, or cyclic. Furthermore, R... L2 R L3 and R L4 Any two atoms in the ring can also bond to each other and form a ring with 3 to 20 carbon atoms together with the carbon atoms they are bonded to, or with carbon and oxygen atoms. The aforementioned rings are preferably 4 to 16 carbon atoms, with alicyclic rings being particularly preferred.

[0235] In equation (AL-3), R L5 R L6 and R L7Each group is an independent hydrocarbon group having 1 to 20 carbon atoms, and may also contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, and iodine. The aforementioned hydrocarbon groups can be linear, branched, or cyclic. Furthermore, R... L5 R L6 and R L7 Any two atoms in the ring can also bond to each other and together with the carbon atoms they are bonded to form a ring with 3 to 20 carbon atoms. The aforementioned ring is preferably a ring with 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0236] Specific examples of repeating unit b1 can be listed below, but are not limited to these. Additionally, in the following formula, R... A and AL 1 Same as above.

[0237] [Chemistry 61]

[0238]

[0239] [Chemistry 62]

[0240]

[0241] [Chemistry 63]

[0242]

[0243] [Chemistry 64]

[0244]

[0245] [Chemistry 65]

[0246]

[0247] [Chemistry 66]

[0248]

[0249] [Chemistry 67]

[0250]

[0251] Specific examples of repeated unit b2 can be listed below, but are not limited to these. Additionally, in the following formula, R... A and AL 2 Same as above.

[0252] [Chemistry 68]

[0253]

[0254] [Chemistry 69]

[0255]

[0256] [Chemistry 70]

[0257]

[0258] The aforementioned base polymer preferably also contains repeating units represented by the following formula (c1) (hereinafter also referred to as repeating unit c1).

[0259] [Chemistry 71]

[0260]

[0261] In the formula, R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0262] 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.

[0263] R 21 It can be a halogen atom, nitro group, cyano group, or a hydrocarbon 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 group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms.

[0264] c is an integer from 1 to 4. d is an integer from 0 to 3. However, 1 ≤ c + d ≤ 5.

[0265] In equation (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 21 The radical can be a halogen atom, nitro group, cyano group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon oxygen group with 1 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms; a hydrocarbon carbonyloxy group with 2 to 20 carbon atoms containing heteroatoms; or a hydrocarbon oxygen 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.

[0266] Specific examples of repeating unit c1 can be listed below, but are not limited to these. Additionally, in the following formula, R... A Same as above.

[0267] [Chemistry 72]

[0268]

[0269] [Chemistry 73]

[0270]

[0271] [Chemistry 74]

[0272]

[0273] [Chemistry 75]

[0274]

[0275] [Chemistry 76]

[0276]

[0277] The aforementioned base polymer preferably also contains a repeating unit represented by the following formula (d1) (hereinafter also referred to as repeating unit d1).

[0278] [Chemistry 77]

[0279]

[0280] In the formula, R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0281] Z 1 Single bond, phenylene, naphthylene, *-C(=O)-OZ 11 -or *-C(=O)-NH-Z 11 - or the phenylene or naphthylene group may be substituted by an alkoxy or halogen atom with 1 to 10 carbon atoms, which may also contain a fluorine atom. * indicates an atomic bond with the carbon atom of the main chain. Z 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms, and the saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or an lactone ring.

[0282] R 31 It is a hydrogen atom, or a group containing at least one of the following structures with 1 to 20 carbon atoms: hydroxyl group (other than phenolic hydroxyl 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)-).

[0283] In equation (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 - or the phenylene or naphthylene group may be substituted by an alkoxy or halogen atom with 1 to 10 carbon atoms, which may also contain a fluorine atom. * indicates an atomic bond with the carbon atom of the main chain. Z 11It is a saturated hydrocarbon group, phenylene group, or naphthylene group having 1 to 10 carbon atoms, and 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 containing at least one of the following structures with 1 to 20 carbon atoms: 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)-).

[0284] Specific examples of repeating unit d1 can be listed below, but are not limited to these. Additionally, in the following formula, R... A Same as above.

[0285] [Chemistry 78]

[0286]

[0287] [Chemistry 79]

[0288]

[0289] [Chemistry 80]

[0290]

[0291] [Chemistry 81]

[0292]

[0293] [Chemistry 82]

[0294]

[0295] [Chemistry 83]

[0296]

[0297] [Chemistry 84]

[0298]

[0299] [Chemistry 85]

[0300]

[0301] [Chemistry 86]

[0302]

[0303] [Chemistry 87]

[0304]

[0305] [Chemistry 88]

[0306]

[0307] [Chemistry 89]

[0308]

[0309] [Chemistry 90]

[0310]

[0311] [Chemistry 91]

[0312]

[0313] [Chemistry 92]

[0314]

[0315] [Chemistry 93]

[0316]

[0317] Regarding repeating units c1 or d1, in ArF lithography, those with lactone rings are particularly preferred, while in KrF lithography, EB lithography, and EUV lithography, those with phenolic sites are preferable.

[0318] The aforementioned polymer may also contain repeating units (hereinafter also referred to as repeating units e) with a structure in which hydroxyl groups are protected by acid-indestructible groups. If the repeating unit e is a structure with one or more hydroxyl groups protected, and the protecting group decomposes and generates hydroxyl groups due to the action of acid, there are no particular restrictions, and it is preferable to be represented by the following formula (e1).

[0319] [Chemistry 94]

[0320]

[0321] In equation (e1), R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 41 It can also contain a (e+1) valence hydrocarbon group with 1 to 30 carbon atoms, which may also contain heteroatoms. R 42 It is an acid-labile group. e is an integer from 1 to 4.

[0322] In equation (e1), R 42 The acid-unstable group indicated is one that has been deprotected by the acid, resulting in the formation of a hydroxyl group. R 42 There are no particular restrictions on the structure, but it is preferable to have an acetal structure, a ketal structure, an alkoxy carbonyl group, or an alkoxy methyl group represented by the following formula (e2), with an alkoxy methyl group represented by the following formula (e2) being particularly preferred.

[0323] [Chemistry 95]

[0324]

[0325] In the formula, * represents an atomic bond. R 43 is a hydrocarbon group having 1 to 15 carbon atoms.

[0326] R 42 Specific examples of the acid-labile group represented by and the alkoxymethyl group represented by formula (e2) and the repeating unit e can be the same as those exemplified in the description of the repeating unit d described in Japanese Patent Laid-Open No. 2020-1-111564.

[0327] 3]]The aforementioned base polymer may also contain a repeating unit f derived from indene, benzofuran, benzothiophene, acenaphthene, chromone, coumarin, norbornadiene or their derivatives. Specific examples of the monomer providing the repeating unit f are as shown below, but are not limited thereto. <000(1037>

[0328] [Chemical formula 96]

[0329]

[0330] The aforementioned base polymer may also contain a repeating unit g derived from styrene, indan, vinylpyridine or vinylcarbazole.

[0331] In the polymer of the present invention, the content ratios of the repeating units a, b1, b2, c1, d1, e, f, and g are preferably 0 < a ≤ 0.4, 0 < b1 ≤ 0.8, 0 ≤ b2 ≤ 0.8, 0 < c1 ≤ 0.6, 0 ≤ d1 ≤ 0.6, 0 ≤ e ≤ 0.3, 0 ≤ f ≤ 0.3, and 0 ≤ g ≤ 0.3, and more preferably 0 < a ≤ 0.3, 0 < b1 ≤ 0.7, 0 ≤ b2 ≤ 0.7, 0 < c1 ≤ 0.5, 0 ≤ d1 ≤ 0.5, 0 ≤ e ≤ 0.2, 0 ≤ f ≤ 0.2, and 0 ≤ g ≤ 0.2. However, a + b1 + b2 + c1 + d1 + e + f + g ≤ 1.0.

[0332] The weight average molecular weight (Mw) of the aforementioned polymer is preferably 1000 to 500000, more preferably 3000 to 100000, and still more preferably 5000 to 20000. If Mw is within this range, sufficient etching resistance can be obtained, and there is no concern about a decrease in resolution due to the inability to ensure the difference in dissolution rate before and after exposure. In addition, in the present invention, Mw is a polystyrene-converted measurement value obtained by gel permeation chromatography (GPC) using tetrahydrofuran (THF) or N,N-dimethylformamide (DMF) as a solvent. When measuring GPC, it is usually carried out at room temperature around 23 degrees, but it can also be carried out at a higher or lower temperature than this.

[0333] Furthermore, regarding the aforementioned polymer molecular weight distribution (Mw / Mn), the influence of Mw / Mn tends to increase as the pattern becomes more regular and refined. Therefore, in order to obtain a resist composition that can be ideally used for fine pattern sizes, Mw / Mn should preferably be a narrow dispersion of 1.0 to 2.0. If it is within the aforementioned range, there are fewer low-molecular-weight and high-molecular-weight polymers, and there is no concern about foreign matter being observed on the pattern after exposure or the pattern shape deteriorating.

[0334] Examples of methods for synthesizing the aforementioned polymers include: polymerizing a monomer that provides the aforementioned repeating unit in an organic solvent by adding a free radical polymerization initiator and heating it.

[0335] 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). Examples of polymerization initiators include: 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylpentanonitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, and lauroyl peroxide. The amount of these initiators added relative to the total monomers used in polymerization should preferably be 0.01–25 mol%. The reaction temperature should preferably be 50–150 °C, preferably 60–100 °C. The reaction time should preferably be 2–24 hours, but considering production efficiency, 2–12 hours is preferred.

[0336] The aforementioned polymerization initiator can be added to the aforementioned monomer solution to supply the reactor, or an initiator solution different from the aforementioned monomer solution can be prepared and supplied to the reactor separately. Since there is a possibility that free radicals generated from the initiator may lead to polymerization and the formation of ultra-high molecular weight polymers during the standby time, from a quality management perspective, the monomer solution and initiator solution should preferably be prepared separately and added dropwise. Acid-labile groups can be used directly introduced into the monomer, or they can be protected or partially protected after polymerization. Furthermore, to adjust the molecular weight, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol can be used in combination. In this case, the amount of these chain transfer agents added relative to the total amount of monomers used to polymerize should preferably be 0.01 to 20 mol%.

[0337] Furthermore, living radical polymerization can be used to obtain polymers with narrow dispersions. This method, known as reversible addition fragmentation chain transfer (RAFT) polymerization, utilizes living radicals. Since free radicals are always present at the polymer ends, by starting polymerization with the first monomer and adding the second monomer as they are consumed, block copolymers consisting of first and second repeating units can be formed. When used in copolymerization, because the free radical concentration in the reaction system remains balanced, copolymerizing many monomers results in narrowly dispersed polymers with narrow dispersions.

[0338] Organic solvents used in RAFT polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, and dioxane. Polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylpentanonitrile), dimethyl 2,2-azobis(2-methylpropionic acid) ester, benzoyl peroxide, and lauroyl peroxide. The polymerization temperature should ideally be 50–80°C. The reaction time should ideally be 2–100 hours, with 5–20 hours being preferred.

[0339] Chain transfer agents are required for RAFT polymerization. Specific examples include: 2-cyano-2-propylphenylthiocarboxylate, 4-cyano-4-phenylthiocarboxythiopentanoic acid, 2-cyano-2-propyldodecyl trithiocarbonate, 4-cyano-4-[(dodecylmercaptothiocarbonyl)mercapto]pentanoic acid, 2-(dodecylthiothiocarboxythio)-2-methylpropionic acid, cyanomethyldodecyl thiocarbonate, cyanomethyl N-methyl-N-phenylthiocarbamate, bis(thiobenzoyl)disulfide, and bis(dodecylmercaptothiocarbonyl)disulfide. Among these, 2-cyano-2-propylphenylthiocarboxylate is the best.

[0340] In the case of monomers containing hydroxyl groups, the hydroxyl groups can be replaced with acetal groups such as ethoxy-ethoxy, which are easily deprotected by acids, during polymerization. After polymerization, deprotection can be carried out using weak acids and water. Alternatively, acetyl groups, formyl groups, trimethylacetyl groups, etc., can be used for replacement first, and alkaline hydrolysis can be carried out after polymerization.

[0341] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene can be copolymerized 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 obtain polyhydroxystyrene or hydroxyvinylnaphthalene.

[0342] Specific examples of alkalis used in alkaline hydrolysis include ammonia and triethylamine. Furthermore, the reaction temperature should ideally be -20 to 100°C, with 0 to 60°C being more preferable. The reaction time should ideally be 0.2 to 100 hours, with 0.5 to 20 hours being more preferable.

[0343] In addition, the amount of each monomer in the aforementioned monomer solution can be appropriately set, for example, in a manner that makes it an ideal content ratio for the aforementioned repeating units.

[0344] Regarding the polymer obtained by the aforementioned manufacturing method, the reaction solution obtained by the polymerization reaction can be used as the final product, or the powder obtained by purification steps such as adding the polymer solution to a poor solvent to obtain the powder can be used as the final product. Considering the viewpoints of work efficiency and quality stabilization, it is advisable to use the polymer solution obtained by dissolving the powder obtained by the purification step into a solvent as the final product.

[0345] Specific examples of solvents used at this time can be cited from paragraphs

[0144] to

[0145] of Japanese Patent Application Publication No. 2008-111103, including ketones such as 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; and propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, and propylene glycol dimethyl ether. Ethers such as diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, 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.

[0346] In the aforementioned polymer solution, the polymer concentration is preferably 0.01~30% by mass, and more preferably 0.1~20% by mass.

[0347] The aforementioned reaction solutions and polymer solutions should be filtered. Filtering removes foreign matter and gels that could cause defects, effectively stabilizing the quality.

[0348] The materials used in the aforementioned filters include fluorocarbon, cellulose, nylon, polyester, and hydrocarbon-based materials. In the filtration step involving chemically amplified resist components, filters made of fluorocarbon (such as Teflon, a registered trademark), polyethylene, polypropylene, or nylon are preferable. The pore size of the filter can be appropriately selected according to the target cleanliness level, preferably below 100 nm, and even better, below 20 nm. Furthermore, a single type of filter can be used. The filtration method can involve passing the solution only once, but circulating the solution and performing multiple filtrations is preferable. The filtration step can be performed during the polymer manufacturing process, in any order and number of times. It is preferable to filter the reaction solution after the polymerization reaction, the polymer solution, or both.

[0349] [Chemical amplification resist composition]

[0350] [(A) Basic Polymer]

[0351] The chemically amplified resist composition of the present invention contains a base polymer comprising the aforementioned polymer as component (A).

[0352] The aforementioned polymers may be used alone or in combination of two or more with different composition ratios, Mw and / or Mw / Mn. Furthermore, (A) the base polymer may include, in addition to the aforementioned polymers, hydrides of ring-opening metathesis polymers, for which the polymers described in Japanese Patent Application Publication No. 2003-66612 may be used.

[0353] In the chemically amplified resist composition of the present invention, the content of (A) the base polymer is not particularly limited. For example, it can be set to 0.1 to 10 parts by mass relative to 100 parts by mass of the composition, and it is more ideal to set it to 0.5 to 5 parts by mass.

[0354] [(B) Organic solvents]

[0355] The chemically amplified resist composition of the present invention may also contain an organic solvent as component (B). There are no particular limitations on whether the organic solvent (B) is capable of dissolving the foregoing 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.

[0356] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and their mixed solvents are particularly suitable for the solubility of the base polymer of component (A).

[0357] 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 200-5000 parts by mass, and more preferably 400-3500 parts by mass. (B) Organic solvent may be used alone or in combination with two or more types.

[0358] [(C) Quenching agent]

[0359] The chemically amplified resist composition of the present invention may also contain a quencher as component (C). Furthermore, in the present invention, the quencher refers to a material that prevents the diffusion of acid generated from the photoacid generator in the chemically amplified resist composition towards the unexposed area by capturing the acid, thereby forming a desired pattern.

[0360] (C) Specific examples of quenching agents can be listed as onion salts represented by formula (1) or (2).

[0361] [Chemistry 97]

[0362]

[0363] In equation (1), R q1 It is a hydrocarbon group with 1 to 40 carbon atoms, which may contain hydrogen atoms or heteroatoms, but excludes those in which the hydrogen atom at the α-position of the sulfonate group is replaced by a fluorine atom or a fluoroalkyl group. In formula (2), R q2 Hydrocarbon groups consisting of 1 to 40 carbon atoms, which may also contain heteroatoms.

[0364] R q1The hydrocarbon groups representing carbon numbers from 1 to 40 can be specifically listed as follows: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, etc., alkyl groups with carbon numbers from 1 to 40; 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, and a portion of the -CH2- group in the aforementioned hydrocarbon groups may also be replaced by groups containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, these 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)-), haloalkyl, etc.]

[0365] R q2 The hydrocarbon group represented can be specifically exemplified as R. q1 In addition to the specific examples of substituents, examples include fluorinated saturated hydrocarbon groups such as trifluoromethyl and trifluoroethyl, and fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl.

[0366] Specific examples of the anions of onium salts represented by equation (1) are listed below, but are not limited thereto.

[0367] [Chem. 98]

[0368]

[0369] [Chemistry 99]

[0370]

[0371] [Chemistry 100]

[0372]

[0373] Specific examples of the anions of onium salts represented by equation (2) are listed below, but are not limited thereto.

[0374] [Chemistry 101]

[0375]

[0376] [Chemistry 102]

[0377]

[0378] [Chemistry 103]

[0379]

[0380] In equations (1) and (2), Mq + The aforementioned onion cation is preferably a sulfonium cation represented by the aforementioned formula (cation-1), a monium cation represented by the aforementioned formula (cation-2), or an ammonium cation represented by the following formula (cation-3).

[0381] [Chemistry 104]

[0382]

[0383] In equation (cation-3), R ct6 ~R ct9 Each can be independently a hydrocarbon group with 1 to 40 carbon atoms, which may also contain heteroatoms. Also, R ct6 and R ct7 They can also bond to each other and form rings together with the nitrogen atoms they are bonded to. Specific examples of the aforementioned hydrocarbon groups can be listed and illustrated in the descriptions of formulas (cation-1) and (cation-2) as R. ct1 ~R ct5 The same example represents hydrocarbon groups.

[0384] Specific examples of ammonium cations represented by formula (cation-3) are listed below, but are not limited thereto.

[0385] [Chemistry 105]

[0386]

[0387] Specific examples of onium salts represented by formula (1) or (2) can be listed as any combination of the aforementioned anions and cations. Furthermore, these onium salts can be easily prepared by ion exchange reactions using known organic chemical methods. For example, Japanese Patent Application Publication No. 2007-145797 can be consulted for examples of ion exchange reactions.

[0388] The onium salts represented by 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 aforementioned onium salts are conjugate bases of weak acids. Here, "weak acid" means an acidity that cannot deprotect the acid-instable groups of the units containing acid-instable groups used in the base polymer. The onium salts represented by formula (1) or (2) function as quenchers when used in combination with onium salt-type photoacid generators that have a conjugate base of a strong acid, such as sulfonic acid with fluorinated α-position, as a relative anion. That is, when onium salts that produce strong acids, such as sulfonic acid with fluorinated α-position, are mixed with onium salts that produce weak acids, such as unfluorinated sulfonic acid or carboxylic acid, if the strong acid generated from the photoacid generator due to high-energy ray irradiation collides with the unreacted onium salt with a weak acid anion, the weak acid is released through salt exchange, and an onium salt with a strong acid anion is generated. During this process, strong acids are exchanged for weak acids with low catalytic activity, thus the acid appears to be deactivated and acid diffusion can be controlled.

[0389] Furthermore, (C) the quenching agent may be an onium salt having a sulfonium cation and a benzene oxide anion site within the same molecule as described in Japanese Patent No. 6848776, or an onium salt having a sulfonium cation and a carboxylate anion site within the same molecule as described in Japanese Patent No. 6583136, Japanese Patent Application Publication No. 2020-200311, or an onium salt having a monazine cation and a carboxylate anion site within the same molecule as described in Japanese Patent No. 6274755.

[0390] Here, it is believed that when the photoacid generator that produces strong acids is an onium salt, as mentioned above, the strong acid generated by high-energy ray irradiation can be exchanged for a weak acid. On the other hand, the weak acid generated by high-energy ray irradiation is not easily exchanged with the unreacted onium salt that produces strong acids. This is because onium cations more readily form ion pairs with the anions of strong acids.

[0391] When the chemically amplified resist composition of the present invention contains an onium salt represented by formula (1) or (2) as a quencher in component (C), its content relative to 80 parts by mass of the base polymer in component (A) is preferably 0.1 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass. If the onium salt type quencher in component (C) is within the aforementioned range, the resolution is good and the sensitivity is not significantly reduced, which is ideal. The onium salt represented by formula (1) or (2) can be used alone or in combination of two or more.

[0392] The chemically amplified resist composition of the present invention may also contain a nitrogen-containing compound as a (C) quencher. Specific examples of nitrogen-containing compounds as component (C) include primary, secondary, or tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Application Publication No. 2008-111103, particularly amine compounds having hydroxyl, ether, ester, lactone ring, cyano, or sulfonate bonds. Furthermore, compounds in which primary or secondary amines are protected with urethane groups, as described in Japanese Patent No. 3790649, may also be cited.

[0393] Alternatively, sulfonate sulfonates with nitrogen-containing substituents can be used as nitrogen-containing compounds. Such compounds function as quenchers in the unexposed areas, but lose their quenching ability in the exposed areas due to neutralization with the acid they generate, thus functioning as so-called photodegrading bases. By using photodegrading bases, the contrast between the exposed and unexposed areas can be enhanced. For example, Japanese Patent Application Publication No. 2009-109595 and Japanese Patent Application Publication No. 2012-46501 can be referenced for photodegrading bases.

[0394] When the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as a quencher (C), its content relative to 80 parts by mass of the base polymer (A) is preferably 0.001 to 12 parts by mass, and 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.

[0395] [(D) Acid generating agent]

[0396] In addition to containing the base polymer (A) as a polymer-bonded photoacid generator, the chemically amplified resist composition of the present invention may also contain an acid generator. Examples of such acid generators include compounds that sense active light or radiation and generate acid (photoacid generators). There are no particular limitations on the type of photoacid generator; it is preferable to be a compound that generates acid upon irradiation by high-energy rays, such as a sulfonic acid, imide acid, or methyl acid. Ideal photoacid generators include: sulfonium salts, sulfonyl diazomethanes, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, etc. Specific examples of acid generators can be found in paragraphs

[0122] to

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

[0397] Furthermore, the photoacid generator can also ideally be a sulfonium salt represented by formula (3-1) or a sulfonium salt represented by formula (3-2).

[0398] [Chemistry 106]

[0399]

[0400] In equations (3-1) and (3-2), R 101 ~R105 Each is a halogen atom or a hydrocarbon group with 1 to 20 carbon atoms, which may also contain heteroatoms. Specific examples of the aforementioned halogen atoms and hydrocarbon groups are given and illustrated in the descriptions of formulas (cation-1) and (cation-2) as R. ct1 ~R ct5 The same examples apply to halogen atoms and hydrocarbon groups. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and a portion of the -CH2- group in the aforementioned hydrocarbon group can also be replaced by groups containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. This results in the presence of 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. Also, R 101 and R 102 They can also bond to each other and form rings together with the sulfur atoms they are bonded to. Specific examples of the rings formed in this case can be listed and illustrated in the explanation of formula (cation-1) as R. ct1 and R ct2 The same example applies to the rings that can be formed by mutual bonding and the sulfur atoms they are bonded to.

[0401] Specific examples of cations of sulfonium salts represented by formula (3-1) can be listed and illustrated as examples of sulfonium cations represented by formula (cation-1). Similarly, specific examples of cations of zirconia salts represented by formula (3-2) can be listed and illustrated as examples of zirconia cations represented by formula (cation-2).

[0402] In equations (3-1) and (3-2), Xa - The anions are selected from formulas (3A) to (3D).

[0403] [Chemistry 107]

[0404]

[0405] In equation (3A), R fa It is a hydrocarbon group with 1 to 40 carbon atoms, which may contain fluorine atoms or heteroatoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be listed and described later in formula (3A'). fa1 The same examples are illustrated in the description.

[0406] The anion represented by formula (3A) should preferably be represented by formula (3A').

[0407] [Chemistry 108]

[0408]

[0409] In equation (3A'), R HF It can be a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group.

[0410] In equation (3A'), R fa1 The hydrocarbon group may contain heteroatoms and has 1 to 38 carbon atoms. The aforementioned heteroatoms are preferably oxygen, nitrogen, sulfur, or halogen atoms, with oxygen atoms being more preferred. Considering the high resolution achieved in the formation of fine patterns, hydrocarbon groups with 6 to 30 carbon atoms are particularly preferred.

[0411] R fa1 The hydrocarbon groups represented by carbon numbers 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.

[0412] Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, 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, sulfur, and nitrogen atoms. This can result in the presence of hydroxyl, fluorine, chlorine, bromine, iodine, cyano, carbonyl, ether, ester, sulfonate, carbonate, lactone ring, sulfonate ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl, etc. Additionally, the aforementioned heteroatoms should preferably be oxygen atoms. 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.

[0413] For details on the synthesis of sulfonium salts containing anions represented by formula (3A'), please refer to Japanese Patent Application Publication Nos. 2007-145797, 2008-106045, 2009-7327, and 2009-258695. Alternatively, sulfonium salts described in Japanese Patent Application Publication Nos. 2010-215608, 2012-41320, 2012-106986, and 2012-153644 may also be used.

[0414] Specific examples of anions represented by formula (3A) are shown below, but are not limited to these. Additionally, in the following formula, Ac represents an acetyl group.

[0415] [Chemistry 109]

[0416]

[0417] [Chemical 110]

[0418]

[0419] [Chemistry 111]

[0420]

[0421] [Chemistry 112]

[0422]

[0423] In equation (3B), R fb1 and R fb2 Each hydrocarbon group consists of 1 to 40 carbon atoms, and may also contain heteroatoms. These hydrocarbon groups may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples can be listed and illustrated as R in formula (3A'). fa1 The same example represents a hydrocarbon group. 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. Also, R fb1 With R fb2 They can also bond to each other and to 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 formed by mutual bonding should preferably be fluorinated ethylidene or fluorinated propyleneide.

[0424] In equation (3C), R fc1 R fc2 and R fc3Each hydrocarbon group consists of 1 to 40 carbon atoms, and may also contain heteroatoms. These hydrocarbon groups may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples can be listed and illustrated as R in formula (3A'). fa1 The same example represents a hydrocarbon group. 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. Also, R fc1 With R fc2 They can also bond to each other and to the groups they are bonded to (-CF2-SO2-C). - -SO2-CF2-) together form a ring, at which point R fc1 With R fc2 The groups formed by mutual bonding should preferably be fluorinated ethylidene or fluorinated propyleneide.

[0425] In equation (3D), R fd It can be a hydrocarbon group with 1 to 40 carbon atoms, which may also contain heteroatoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be listed and illustrated as R in formula (3A'). fa1 The same example represents hydrocarbon groups.

[0426] For details on the synthesis of sulfonium salts containing anions represented by formula (3D), please refer to Japanese Patent Application Publication No. 2010-215608 and Japanese Patent Application Publication No. 2014-133723.

[0427] Specific examples of anions represented by formula (3D) are listed below, but are not limited thereto.

[0428] [Chemistry 113]

[0429]

[0430] [Chemistry 114]

[0431]

[0432] Furthermore, photoacid generators containing anions represented by formula (3D), although lacking a fluorine atom at the α-position of the sulfonyl group, possess two trifluoromethyl groups at the β-position, thus still exhibiting sufficient acidity to cleave acid-indestructible groups in the base polymer. Therefore, they can be used as photoacid generators.

[0433] Photoacid generators can also ideally be represented by the following formula (4).

[0434] [Chemistry 115]

[0435]

[0436] In equation (4), R 201 and R 202 Each can be independently a hydrocarbon group with 1 to 30 carbon atoms, which may also contain heteroatoms. R 203 It can also contain a hydrocarbon group with 1 to 30 carbon atoms and a heteroatom. Also, R 201 R 202 and R 203 Any two atoms in the ring can also bond to each other and form a ring together with the sulfur atoms they are bonded to. In this case, specific examples of the aforementioned rings can be listed and illustrated in the description of formula (cation-1) as R. ct1 and R ct2 The same example applies to the rings that can be formed by mutual bonding and the sulfur atoms they are bonded to.

[0437] R 201 and R 202 The hydrocarbon groups representing 1 to 30 carbon atoms can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, etc., alkyl groups with 1 to 30 carbon atoms; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornel, oxanorbornel, 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, tolyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, tert-butylnaphthyl, and anthracene; and groups obtained by combining these. 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, and some of the -CH2- group in the aforementioned hydrocarbon groups may also 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 ring, sulfonyl lactone ring, carboxylic anhydride (-C(=O)-OC(=O)-), or haloalkyl groups.]

[0438] R 203The alkylene groups representing carbon atoms from 1 to 30 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-1,1... Alkyl groups with 1 to 30 carbon atoms, such as 7-diyl; cyclic saturated hydrocarbon groups with 3 to 30 carbon atoms, such as cyclopentanediyl, cyclohexanediyl, norcamphenediyl, and adamantanediyl; 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, and tert-butylnaphthylene; and groups formed by combining these groups. Furthermore, some or all of the hydrogen atoms in the aforementioned alkylene group can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and a portion of the -CH2- group in the aforementioned alkylene group can also be replaced by groups containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. This can result in the presence of hydroxyl, cyano, fluorine, chlorine, bromine, iodine, carbonyl, ether, ester, sulfonate, carbonate, lactone, sulfonate, carboxylic anhydride (-C(=O)-OC(=O)-), or haloalkyl groups. The aforementioned heteroatoms should preferably be oxygen atoms.

[0439] In equation (4), L A It is a hydrocarbon group with 1 to 20 carbon atoms, which can 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 and illustrated as R. 203 The same example represents the subhydrocarbon group.

[0440] In equation (4), X A X B X C and X D Each can be independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. However, X A X B X C and X D At least one of them is a fluorine atom or a trifluoromethyl group.

[0441] In equation (4), k is an integer from 0 to 3.

[0442] The photoacid generator represented by formula (4) should preferably be represented by the following formula (4').

[0443] [Chemistry 116]

[0444]

[0445] In equation (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 can be an independent hydrocarbon group with 1 to 20 carbon atoms, which may also contain heteroatoms. The aforementioned hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples can be listed and illustrated as R in formula (3A'). fa1 The same example represents hydrocarbon groups. x and y are independent integers from 0 to 5. z is an integer from 0 to 4.

[0446] Specific examples of photoacid generators represented by formula (4) can be cited as the same examples as those exemplified in Japanese Patent Application Publication No. 2017-26980 as photoacid generators represented by formula (2).

[0447] Among the aforementioned photoacid generators, those containing anions represented by formula (3A') or (3D) exhibit low acid diffusion and excellent solvent solubility, making them particularly ideal. Furthermore, those represented by formula (4') exhibit extremely low acid diffusion, making them particularly ideal.

[0448] Alternatively, sulfonium salts and sulfonium salts containing anions with aromatic rings substituted with iodine atoms, represented by formulas (5-1) or (5-2), can also be used as other acid generating agents.

[0449] [Chemistry 117]

[0450]

[0451] In equations (5-1) and (5-2), p is 1, 2, or 3. q and r are integers that satisfy 1≤q≤5, 0≤r≤3, and 1≤q+r≤5. q should preferably be 1, 2, or 3, with 2 or 3 being more preferable. r should preferably be 0, 1, or 2.

[0452] In equations (5-1) and (5-2), L 1 It is a saturated hydrocarbon group with 1 to 6 carbon atoms, consisting of a single bond, ether bond, or ester bond, or may also contain ether or ester bonds. The aforementioned saturated hydrocarbon group can be linear, branched, or cyclic.

[0453] In equations (5-1) and (5-2), L 2When 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, and the linker may also contain oxygen, sulfur or nitrogen atoms.

[0454] In equations (5-1) and (5-2), R 401 It may be a hydroxyl, carboxyl, fluorine, chlorine, bromine, or amino group, or may contain a fluorine, chlorine, bromine, hydroxyl, amino, or ether bond, and may be a hydrocarbon group with 1 to 20 carbon atoms, a hydrocarbon oxygen group with 1 to 20 carbon atoms, a hydrocarbon carbonyl group with 2 to 20 carbon atoms, a hydrocarbon carbonyl oxygen group with 2 to 20 carbon atoms, or a hydrocarbon sulfonyl oxygen group with 1 to 20 carbon atoms, or -N(R 401A (R) 401B ), -N(R 401C )-C(=O)-R 401D or -N(R) 401C )-C(=O)-OR 401D R 401A and R 401B Each can be 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 oxygen group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyl oxygen group having 2 to 6 carbon atoms. R 401D It can be an aliphatic hydrocarbon group with 1 to 16 carbon atoms, an aryl group with 6 to 14 carbon atoms, or an aralkyl group with 7 to 15 carbon atoms, and may also contain a halogen atom, a hydroxyl group, a saturated alkyloxy group with 1 to 6 carbon atoms, a saturated alkylcarbonyl group with 2 to 6 carbon atoms, or a saturated alkylcarbonyloxy group with 2 to 6 carbon atoms. The aforementioned aliphatic hydrocarbon group can be saturated or unsaturated, and can be straight-chain, branched, or cyclic. The aforementioned hydrocarbon group, alkyloxy group, alkylcarbonyl group, alkyloxycarbonyl group, alkylcarbonyloxy group, and alkylsulfonyloxy group can be straight-chain, branched, or cyclic. When p and / or r is 2 or more, each R 401 They can be the same or different.

[0455] Among them, R 401 It is advisable to use hydroxyl groups, -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.

[0456] In equations (5-1) and (5-2), Rf 1 ~Rf 4 Each of these can be independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one of them must be a fluorine atom or a trifluoromethyl group. Also, Rf1 With Rf 2 They can also combine to form carbonyl groups. Especially Rf 3 and Rf 4 Both are ideally composed of fluorine atoms.

[0457] In equations (5-1) and (5-2), R 402 ~R 406 Each of the above is a hydrocarbon group consisting of 1 to 20 carbon atoms, which may also contain heteroatoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples are given in the descriptions of formulas (cation-1) and (cation-2) as R. ct1 ~R ct5 The same example applies to the hydrocarbon group. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon group may be replaced by hydroxyl, carboxyl, halogen, cyano, nitro, mercapto, sulfonyl lactone ring, sulfonyl, or sulfonium salt-containing groups, and a portion of the -CH2- group in the aforementioned hydrocarbon group may be replaced by ether, ester, carbonyl, amide, carbonate, or sulfonate bonds. Also, R 402 and R 403 They can also bond to each other and form rings together with the sulfur atoms they are bonded to. In this case, specific examples of the aforementioned rings can be listed and illustrated in the description of formula (cation-1) as R. ct1 and R ct2 The same example applies to the rings that can be formed by mutual bonding and the sulfur atoms they are bonded to.

[0458] Specific examples of the cations of sulfonium salts represented by formula (5-1) can be listed and illustrated as examples of the sulfonium cations represented by formula (cation-1). Similarly, specific examples of the cations of zirconia salts represented by formula (5-2) can be listed and illustrated as examples of the zirconia cations represented by formula (cation-2).

[0459] Specific examples of onium salt anions represented by formula (5-1) or (5-2) are listed below, but are not limited thereto.

[0460] [Chemistry 118]

[0461]

[0462] [Chemistry 119]

[0463]

[0464] [Chemistry 120]

[0465]

[0466] [Chemistry 121]

[0467]

[0468] [Chemistry 122]

[0469]

[0470] [Chemistry 123]

[0471]

[0472] [Chemistry 124]

[0473]

[0474] [Chemistry 125]

[0475]

[0476] [Chemistry 126]

[0477]

[0478] [Chemistry 127]

[0479]

[0480] [Chemistry 128]

[0481]

[0482] [Chemistry 129]

[0483]

[0484] [Chemistry 130]

[0485]

[0486] [Chemistry 131]

[0487]

[0488] [Chemistry 132]

[0489]

[0490] [Chemistry 133]

[0491]

[0492] [Chemistry 134]

[0493]

[0494] [Chemistry 135]

[0495]

[0496] [Chemistry 136]

[0497]

[0498] [Chemistry 137]

[0499]

[0500] [Chemistry 138]

[0501]

[0502] [Chemistry 139]

[0503]

[0504] When the chemically amplified resist composition of the present invention contains 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. If the amount of acid-generating agent (D) added is within the aforementioned range, the resolution is good, and there is no concern about foreign matter forming in the resist film after development or during peeling, which is ideal. Acid-generating agent (D) can be used alone or in combination of two or more.

[0505] [(E) Surfactant]

[0506] The chemically amplified resist composition of the present invention may also contain a surfactant as component (E). The surfactant (E) is preferably 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 Nos. 2010-215608 and 2011-16746.

[0507] Surfactants that are insoluble or poorly soluble in water and alkaline developing solutions, among those listed in the aforementioned announcement, are preferably FC-4430 (manufactured by 3M Corporation), SURFLON (registered trademark) S-381 (manufactured by AGC SEIMI CHEMICAL), OLFINE (registered trademark) E1004 (manufactured by Nissin Chemical Industry Co., Ltd.), KH-20, KH-30 (manufactured by AGC SEIMI CHEMICAL), and oxane ring-opening polymers represented by the following formula (surf-1).

[0508] [Chemistry 140]

[0509]

[0510] Here, R, Rf, A, B, C, m, and n are irrelevant to the foregoing description and apply only to formula (surf-1). R is an aliphatic group with 2 to 5 carbon atoms, valent to 2 to 4. Examples of the aforementioned aliphatic groups, for those with a valent charge, include: ethylene, 1,4-butylene, 1,2-propylene, 2,2-dimethyl-1,3-propylene, 1,5-pentane, etc.; examples of those with a valent charge or a tetravalent charge include the following.

[0511] [Chemistry 141]

[0512]

[0513] In the formula, the dashed lines represent atomic bonds, which are partial structures derived from glycerol, trimethylolethane, trimethylolpropane, and neopentyl tertrol, respectively.

[0514] Among them, 1,4-butylene, 2,2-dimethyl-1,3-propylene, etc. are preferred.

[0515] Rf is trifluoromethyl or pentafluoroethyl, preferably trifluoromethyl. m is an integer from 0 to 3, n is an integer from 1 to 4, the sum of n and m is the valence of R, and is an integer from 2 to 4. A is 1. B is an integer from 2 to 25, preferably an integer from 4 to 20. C is an integer from 0 to 10, preferably 0 or 1. Furthermore, the arrangement of the constituent units in formula (surf-1) is not specified; they can be block-bonded or randomly bonded. For details on the manufacture of surfactants in partially fluorinated oxyheterocyclic butane ring-opening polymer systems, please refer to the specification of US Patent No. 5,650,483, etc.

[0516] Surfactants that are insoluble or sparingly soluble in water but soluble in alkaline developing solutions are useful in ArF immersion lithography when no resist film is used. They reduce water penetration and leaching by aligning with the surface of the resist film. Therefore, they are useful for suppressing the leaching of water-soluble components from the resist film and reducing damage to the exposure equipment. Furthermore, they are useful as foreign substances that can be dissolved in alkaline aqueous solutions after exposure or post-exposure baking (PEB) and are unlikely to 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 desirable for those with high water repellency and improved hydrophobic properties.

[0517] Specific examples of such polymeric surfactants include those containing at least one of the repeating units represented by formulas (6A) to (6E).

[0518] [Chemistry 142]

[0519]

[0520] In equations (6A) to (6E), R BIt 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 can be 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 can be independently a hydrogen atom, a hydrocarbon group with 1 to 15 carbon atoms, a fluorinated hydrocarbon group, or an acid-labile group. R s3 When the group is a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group can also be inserted between the 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 can be 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 a fluorinated hydrocarbon group with 1 to 15 carbon atoms, and an ether bond or a carbonyl group may also be inserted between its carbon-carbon bonds.

[0521] R s1 The 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.

[0522] 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.

[0523] R s3 or R s6 The hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include: saturated hydrocarbon groups; aliphatic unsaturated hydrocarbon groups such as alkenyl and alkynyl groups, which are preferably saturated hydrocarbon groups. Specific examples of the aforementioned saturated hydrocarbon groups can be listed as R. s1 In addition to the hydrocarbon groups indicated by R, other examples include undecyl, dodecyl, tridecyl, tetradecyl, and pentadecyl. s3 or R s6 Specific examples of fluorinated hydrocarbon groups can be listed as groups in which some or all of the hydrogen atoms of the carbon atom bonded to the aforementioned hydrocarbon group are replaced by fluorine atoms. As mentioned above, ether bonds or carbonyl groups may also be inserted between their carbon-carbon bonds.

[0524] R s3 Specific examples of acid-instable groups can be listed as follows: groups represented by the aforementioned formulas (AL-1) to (AL-3), trialkylsilyl groups with alkyl groups having 1 to 6 carbon atoms, and alkyl groups containing oxygen groups having 4 to 20 carbon atoms.

[0525] R s4 The (u+1) valence hydrocarbon group or fluorinated hydrocarbon group can be any of the following: straight chain, branched, or cyclic. Specific examples can be listed as groups obtained by further removing u hydrogen atoms from the aforementioned hydrocarbon group or fluorinated hydrocarbon group.

[0526] R sa The fluorinated hydrocarbon group represented should preferably be saturated and can be linear, branched, or cyclic. Specific examples include those in which some or all of the hydrogen atoms of the aforementioned hydrocarbon group are replaced by fluorine atoms, such as: trifluoromethyl, 2,2,2-trifluoroethyl, 3,3,3-trifluoro-1-propyl, 3,3,3-trifluoro-2-propyl, 2,2,3,3-tetrafluoropropyl, 1,1,1,3,3,3-hexafluoroisopropyl, 2,2,3,3,4,4,4-heptafluorobutyl, 2,2,3,3,4,4,5,5-octafluoropentyl, 2,2,3,3,4,4,5,5,6,6,7,7-dodecylfluoroheptyl, 2-(perfluorobutyl)ethyl, 2-(perfluorohexyl)ethyl, 2-(perfluorooctyl)ethyl, 2-(perfluorodecyl)ethyl, etc.

[0527] Specific examples of the repeating units represented by any of equations (6A) to (6E) can be listed below, but are not limited thereto. Additionally, in the following equation, R... B Same as above.

[0528] [Chemistry 143]

[0529]

[0530] [Chemistry 144]

[0531]

[0532] [Chemistry 145]

[0533]

[0534] [Chemistry 146]

[0535]

[0536] [Chemistry 147]

[0537]

[0538] The aforementioned polymeric surfactants may also contain repeating units other than those represented by formulas (6A) to (6E). Specific examples of other repeating units include repeating units derived from methacrylic acid, α-trifluoromethacrylic acid derivatives, etc. In polymeric surfactants, the content of repeating units represented by 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.

[0539] The Mw of the aforementioned polymeric surfactant is preferably 1,000 to 500,000, and more preferably 3,000 to 100,000. The Mw / Mn ratio is preferably 1.0 to 2.0, and more preferably 1.0 to 1.6.

[0540] Methods for synthesizing the aforementioned polymeric surfactants include: monomers containing unsaturated bonds, representing repeating units (6A) to (6E) and other repeating units as needed, are polymerized in an organic solvent by adding a free radical initiator and heating. Examples of organic solvents used in polymerization include toluene, benzene, THF, diethyl ether, and dioxane. Examples of polymerization initiators include AIBN, 2,2'-azobis(2,4-dimethylpentanonitrile), dimethyl 2,2-azobis(2-methylpropionic acid), benzoyl peroxide, and lauroyl peroxide. The reaction temperature should be 50–100°C. The reaction time should be 4–24 hours. Acid-labile groups can be directly introduced into the monomer, or they can be protected or partially protected after polymerization.

[0541] When synthesizing the aforementioned polymeric surfactants, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol can be used to adjust the molecular weight. In this case, the amount of these chain transfer agents added relative to the total molar number of monomers used to polymerize them should preferably be 0.01 to 10 mol%.

[0542] When the chemically amplified resist composition of the present invention contains surfactant (E), its content relative to 80 parts by weight of the base polymer (A) is preferably 0.1 to 50 parts by weight, and more preferably 0.5 to 10 parts by weight. If the content of surfactant (E) is 0.1 parts by weight or more, it will sufficiently improve the receding contact angle between the resist film surface and water; if it is 50 parts by weight or less, the dissolution rate of the resist film surface to the developer is low, and the height of the formed fine pattern is sufficiently maintained. Surfactant (E) can be used alone or in combination of two or more.

[0543] [(F) Dissolution Inhibitor]

[0544] The chemically amplified resist composition of the present invention may also contain a dissolution inhibitor as component (F). When the chemically amplified resist composition of the present invention is positive, by incorporating a dissolution inhibitor, the dissolution rate difference between the exposed and unexposed areas can be further increased, and the resolution can be further improved.

[0545] Specific examples of the aforementioned dissolution inhibitors include: compounds in which the hydrogen atom of the phenolic hydroxyl group in a compound having a molecular weight preferably of 100 to 1000 and more preferably 150 to 800 and containing two or more phenolic hydroxyl groups is replaced by an acid-unstable group at a ratio of 0 to 100 mol% in general; or compounds in which the hydrogen atom of the carboxyl group in a compound containing a carboxyl group is replaced by an acid-unstable group at an average ratio of 50 to 100 mol% in general. Specifically, examples include compounds in which the hydrogen atoms of the hydroxyl and carboxyl groups of bisphenol A, triphenol, phenolphthalein, cresol phenolic varnish resin, naphtholic acid, adamantane carboxylic acid, and cholic acid are replaced by acid-unstable groups, such as those described in paragraphs

[0155] to

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

[0546] When the chemically amplified resist composition of the present invention contains a dissolution inhibitor (F), its content relative to 80 parts by weight of the base polymer (A) is preferably 0 to 50 parts by weight, and more preferably 5 to 40 parts by weight.

[0547] [(G) Other ingredients]

[0548] The chemically amplified resist composition of the present invention may also contain compounds that decompose due to acid and produce acid (acid-increasing compounds), organic acid derivatives, fluorinated alcohols, water-repellent improvers, etc., as other components in (G). The aforementioned acid-increasing compounds can be referred to in Japanese Patent Application Publication No. 2009-269953 or Japanese Patent Application Publication No. 2010-215608. When containing the aforementioned acid-increasing compounds, their content relative to 80 parts by mass of the base polymer in (A) is preferably 0 to 5 parts by mass, more preferably 0 to 3 parts by mass. Excessive content may sometimes make acid diffusion control difficult, leading to degradation of resolution and pattern shape. The aforementioned organic acid derivatives and fluorinated alcohols can be referred to in Japanese Patent Application Publication No. 2009-269953 or Japanese Patent Application Publication No. 2010-215608.

[0549] The aforementioned water-repellent improver can be used in immersion lithography without a surface coating. The aforementioned water-repellent improver is preferably a polymer containing fluorinated alkyl groups, or a polymer containing 1,1,1,3,3,3-hexafluoro-2-propanol residues with a specific structure, as 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. Regarding water-repellent improvers, polymers containing repeating units containing amino or amine salts are highly effective in preventing acid evaporation during PEB and in preventing poor opening of the hole pattern after development. When the chemically amplified corrosion inhibitor composition of the present invention contains the aforementioned water repellency improver, its content relative to 80 parts by weight of (A) base polymer is preferably 0 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight.

[0550] [Pattern Formation Method]

[0551] When the chemically amplified resist composition of the present invention is used in the manufacture of various integrated circuits, known photolithography techniques can be employed. For example, regarding pattern formation methods, methods comprising the following steps can be listed:

[0552] A resist film is formed on the substrate using the aforementioned chemically amplified resist composition.

[0553] The aforementioned resist film was exposed to high-energy rays, and

[0554] The previously exposed resist film was developed using a developer.

[0555] First, the chemically amplified resist composition of the present invention is coated onto a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflective film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) using a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, or blade coating, with a coating film thickness of 0.01~2.0 μm. The substrate is then pre-baked on a hot plate, preferably at 60~150°C for 10 seconds~30 minutes, and more preferably at 80~120°C for 30 seconds~20 minutes, to form a resist film.

[0556] Then, the aforementioned photoresist film is exposed using high-energy radiation. Examples of such high-energy radiation include: ultraviolet light, far ultraviolet light, EB, EUV (wavelength 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, the exposure dose should be approximately 1-200 mJ / cm², either directly or using a mask to form the desired pattern. 2 And preferably, it should be approximately 10~100 mJ / cm 2 Irradiation is performed in the manner described above. When using EB for the aforementioned high-energy rays, the exposure dose should preferably be approximately 0.1~100 μC / cm. 2 And preferably, it should be 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 the present invention is particularly suitable for fine patterning in high-energy radiation such as ArF excimer lasers with a wavelength of 193 nm, KrF excimer lasers with a wavelength of 248 nm, EB or EUV (extreme ultraviolet radiation) with a wavelength of 3-15 nm, X-rays, soft X-rays, gamma rays or synchrotron radiation.

[0557] After exposure, PEB can also be applied on a heating plate at a temperature of 60-150°C for 10-30 seconds, and more preferably at 80-120°C for 30-20 seconds.

[0558] After exposure or PEB, a developer solution containing 0.1-10% by mass, preferably 2-5% by mass, of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc., is used. The development is performed using common methods such as dip, immersion, or spray for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes. The exposed areas will dissolve in the developer solution, while the unexposed areas will not dissolve, thus forming the desired positive pattern on the substrate.

[0559] Alternatively, the aforementioned alkaline aqueous solution can be replaced with an organic solvent developer to obtain a negative pattern. Specific examples of developers used in this case include: 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methyl acetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butenyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl valerate, methyl crotonate. These organic solvents 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, ethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, and 2-phenylethyl acetate. One of these organic solvents can be used alone, or two or more can be used in combination.

[0560] Rinsing may also be performed at the end of development. The rinsing solution should be a solvent that is miscible with the developer and does not dissolve the resist film. Ideally, such solvents include alcohols with 3 to 10 carbon atoms, ether compounds with 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents with 6 to 12 carbon atoms.

[0561] Specific examples of alcohols with 3 to 10 carbon atoms include: n-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentanol, neopentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol, etc.

[0562] Specific examples of the aforementioned ether compounds with 8 to 12 carbon atoms include: di-n-butyl ether, diisobutyl ether, di(sec-butyl) ether, di-n-pentyl ether, diisopentyl ether, di(sec-pentyl) ether, di(tert-pentyl) ether, di-n-hexyl ether, etc.

[0563] Specific examples of alkanes with 6-12 carbon atoms include: hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, etc. Specific examples of alkenes with 6-12 carbon atoms include: hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Specific examples of alkynes with 6-12 carbon atoms include: hexyne, heptyne, octyne, etc.

[0564] Specific examples of solvents in the aforementioned aromatic family include: toluene, xylene, ethylbenzene, cumene, tert-butylbenzene, mesitylene, etc.

[0565] By performing rinsing, the collapse of the resist pattern and the occurrence of defects can be reduced. Furthermore, rinsing is not necessary; by not performing rinsing, the amount of solvent used can be reduced.

[0566] After development, the hole and groove patterns can be shrunk using heat transfer, RELACS, or DSA techniques. A shrinkage agent is applied to the hole pattern, and during baking, the diffusion of the acid catalyst from the resist film causes cross-linking of the shrinkage agent on the surface of the resist film. The shrinkage agent then adheres to the sidewalls of the hole pattern. The baking temperature is preferably 70–180°C, with 80–170°C being more ideal, and the baking time is preferably 10–300 seconds. This process removes excess shrinkage agent and reduces the size of the hole pattern.

[0567] Example

[0568] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. Furthermore, the apparatus used is described below.

[0569] MALDI TOF-MS: S3000 manufactured by Nippon Electronics Co., Ltd.

[0570] UPLC: ACQUITY UPLC H-Class Plus manufactured by Waters

[0571] The raw materials for the synthesis of onium salt type monomers are the following carboxylic acids (SM-a1~a6), fluorostyrene (SM-b1~b2), fluoroalcohol derivatives (SM-c1~c4), sulfonium salts and tungsten salts (SM-d1~d5).

[0572] [Chemistry 148]

[0573]

[0574] [Chemistry 149]

[0575]

[0576] [Chemistry 150]

[0577]

[0578] [Chemistry 151]

[0579]

[0580] [1] Synthesis of onium salt monomers

[0581] [Example 1-1] Synthesis of onium salt type monomer (a-1)

[0582] [Chemistry 152]

[0583]

[0584] (1) Synthesis of intermediate In-1

[0585] Under nitrogen atmosphere, 32.3 g of starting material (SM-a1), 19.6 g of potassium carbonate, and 200 g of DMF (N,N-dimethylformamide) were added to a reaction vessel and uniformly dispersed at an internal temperature of 40 °C. Then, 25.0 g of starting material (SM-b1), pre-dissolved in 50 g of DMF, 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 then added dropwise to a mixture of 300 ml of MIBK and 300 g of 5% HCl aqueous solution for neutralization. After neutralization, the solution was transferred to a separatory funnel, and the separated aqueous layer was removed. The mixture was washed five times with 100 ml of ultrapure water, and the organic phase was recovered. After distillation of the organic phase, recrystallization was performed with IPE (diisopropyl ether) to obtain 35.8 g of intermediate (In-1) as white crystals (yield 67%).

[0586] (2) Synthesis of intermediate In-2

[0587] Under nitrogen atmosphere, 35.0 g of intermediate (In-1), 200 g of dichloromethane, and 0.05 g of DMF were added to prepare a homogeneous dispersion. The mixture was cooled simultaneously in a water bath and an ice bath, and 11.2 g of oxaloyl chloride was added dropwise. After the addition, the reaction was carried out at room temperature for 12 hours. After the reaction was completed, the residual low-boiling components in the solution were distilled off, and the solution was diluted again with dichloromethane. 160.5 g of intermediate (In-2) ​​was recovered as a 25% dichloromethane solution (yield calculated as 100%). This solution was used in the next step without further purification.

[0588] (3) Synthesis of intermediate In-3

[0589] Under nitrogen atmosphere, a homogeneous solution was prepared in a reaction vessel consisting of 30.0 g of starting material (SM-c1), 10.6 g of TEA (triethylamine), 1.1 g of DMAP (4-dimethylaminopyridine), and 150 g of dichloromethane. While cooling in an ice bath, 160.0 g of a 25 wt% dichloromethane solution of intermediate In-2 (equivalent to 40.0 g of solids) was added dropwise over 30 minutes. After the addition was complete, the reaction was carried out at room temperature for 12 hours, and then 100 g of 3% HCl aqueous solution was added to stop the reaction. After the reaction stopped, the solution was transferred to a separatory funnel, the separated aqueous layer was removed, and the mixture was washed five times with 100 ml of ultrapure water to recover the organic phase. The organic phase was distilled off, and the solution was recrystallized with IPE to obtain 64.1 g of intermediate (In-3) as white crystals (yield 82%).

[0590] (4) Synthesis of onium salt type monomer a-1

[0591] Under nitrogen atmosphere, 60.0 g of intermediate (In-3), 34.3 g of (SM-d1), 300 g of dichloromethane, and 150 g of ultrapure water were added to a 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 then washed five times with 150 g of ultrapure water. The organic phase was recovered and concentrated under reduced pressure. The concentrate was purified by silica gel chromatography, yielding 60.5 g of the onium salt monomer (a-1) as the target monomer (82% yield) as white crystals.

[0592] MALDI TOF-MS:

[0593] POSITIVE M + 261 (equivalent to C) 18 H 13 S + )

[0594] NEGATIVE M - 648 (equivalent to C) 17 H8F6IO6S1 - )

[0595] [Examples 1-2~1-6] Synthesis of onium salt type monomers (a-2)~(a-6)

[0596] Using the same synthetic route as that used for the synthesis of the onium salt type monomer (a-1) in [Example 1-1], and by appropriately selecting the starting materials from carboxylic acids (SM-a1~a6), fluorostyrene (SM-b1~b2), fluoroalcohol derivatives (SM-c1~c4), sulfonium salts, and monazite salts (SM-d1~d5) to synthesize the onium salt type monomers (a-2)~(a-6), in conjunction with the monomers to be synthesized, the onium salt type monomers (a-2)~(a-6) can be synthesized. The structural formulas of the synthesized onium salt type monomers (a-1)~(a-6) are shown below.

[0597] [Chemistry 153]

[0598]

[0599] [Comparative Examples 1-1 to 1-4] Comparison of the synthesis of onium salt monomers (ca-1) to (ca-4)

[0600] Using the corresponding raw materials and known organic synthesis reactions, comparative onium salt monomers (ca-1)~(ca-4) represented by the following formula were synthesized.

[0601] [Chemistry 154]

[0602]

[0603] [2] Synthesis of basic polymers

[0604] The monomers used in the synthesis of the basic polymer, other than the onium salt monomers (a-1) to (a-6) and the comparative monomers (ca-1) to (ca-4), are as follows.

[0605] [Chemistry 155]

[0606]

[0607] [Chemistry 156]

[0608]

[0609] [Chemistry 157]

[0610]

[0611] [Example 2-1] Synthesis of polymer (P-1)

[0612] Under nitrogen atmosphere, 22.2 g of 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) were added to a flask to prepare a monomer-polymerization initiator solution. In another reaction vessel conditioned under nitrogen atmosphere, 23 g of MEK was added, and the mixture was heated to 80°C with stirring. The aforementioned monomer-polymerization initiator solution was then added dropwise over 4 hours. After the addition was complete, the polymerization solution was maintained at 80°C with continuous stirring for 2 hours, and then cooled to room temperature. The resulting polymerization solution was added dropwise to 1500 g of hexane under vigorous stirring, and the precipitated polymer was separated by filtration. The obtained polymer was washed twice with 300 g of hexane and then vacuum dried at 50°C for 20 hours to obtain a white powdered polymer (P-1) (yield 48.5 g, 97% yield). The Mw of polymer (P-1) was 9100, and the Mw / Mn ratio was 1.71. In addition, Mw is the polystyrene conversion value determined by GPC using DMF as a solvent.

[0613] [Chemistry 158]

[0614]

[0615] [Examples 2-2 to 2-23, Comparative Examples 2-1 to 2-8] Synthesis of polymers (P-2 to P-23) and comparative polymers (CP-1) to (CP-8)

[0616] The polymers shown in Tables 1 and 2 were synthesized using the same method as in Example 2-1, except that the types and blending ratios of the monomers were changed. Additionally, polymer (P-24) was synthesized using the polymerization method described above with the RAFT agent; the synthesis results are summarized in Tables 1 and 2.

[0617] Furthermore, the residual amount of onium salt monomers quantified by UPLC is also recorded.

[0618] [Table 1]

[0619]

[0620] [Table 2]

[0621]

[0622] [Examples 2-24] Synthesis of polymer (P-24)

[0623] Under nitrogen atmosphere, 22.2 g of 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) were added to a flask to prepare a monomer-polymerization initiator solution. In another reaction vessel conditioned under nitrogen atmosphere, 23 g of MEK and 3.0 g of RAFT agent (2-cyano-2-propyldodecyl trithiocarbonate) were added. The mixture was heated to 80°C with stirring, and the aforementioned 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, 7.10 g of 1-dodecylthiol was added as an end-treatment agent, and the mixture was stirred for another 3 hours before cooling to room temperature. The resulting polymerization solution was added dropwise to 1500 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 vacuum dried at 50°C for 20 hours to obtain a white powder polymer (P-24) (yield 50.5g). The Mw of polymer (P-24) was 9200, and the Mw / Mn ratio was 1.37. Furthermore, Mw is a polystyrene conversion value determined by GPC using DMF as a solvent.

[0624] [Chemistry 159]

[0625]

[0626] [3] Monomer solvent solubility test

[0627] [Examples 3-1 to 3-6, Comparative Examples 3-1 to 3-4]

[0628] Solvent solubility tests were conducted using the aforementioned onium salt monomers (a-1) to (a-6) and the comparative monomers (Ca-1) to (Ca-4). The solvent solubility tests used PGME (propylene glycol monomethyl ether), DAA (diacetone alcohol), propylene glycol monomethyl ether acetate (PGMEA), ethyl lactate (EL), cyclohexanone (CyHO), and GBL (γ-butyrolactone). The test method involved mixing monomers (a-1) to (a-6) and (Ca-1) to (Ca-4) in 10 wt% and 20 wt% solutions respectively in each solvent, and visually confirming the solubility at room temperature. The test results were rated as follows: ○ for solubility up to 20 wt%, △ for solubility up to 10 wt%, and × for the presence of residue even at 10 wt%. The results are summarized in Table 3.

[0629] [Table 3]

[0630]

[0631] As shown in Table 3, the monomers of the present invention (Examples 3-1 to 3-6) exhibited solvent solubility of 10 wt% or more in all solvents. Compared with comparative examples (Comparative Examples 3-1 to 3-4) that did not have fluorine substituents on the aromatic ring of the styrene structure, it can be seen that the solvent solubility was improved. Furthermore, comparing Examples 3-2 and 3-1, 3-3 to 3-6 with different numbers of fluorine substituents on the styrene structure, it can be seen that by setting all the substituents on the aromatic ring to fluorine, the solvent solubility was improved. In addition, comparing (Examples 3-1, 3-5) and (Examples 3-3, 3-4, 3-6), as described above, by placing the substituents at specific substitution positions relative to the styrene structure, the solvent solubility can be further improved.

[0632] [4] Preparation of chemically amplified resist composition

[0633] [Examples 4-1 to 4-24, Comparative Examples 4-1 to 4-8]

[0634] A predetermined composition of the base polymers (P-1 to P-24) selected from the present invention, the comparative base polymers (CP-1 to CP-8), the acid generators (PAG-1, PAG-2), and the quenchers (SQ-1 to SQ-4) 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) type filter to prepare chemically amplified resist compositions (R-1 to R-24, CR-1 to CR-8).

[0635] [Table 4]

[0636]

[0637] [Table 5]

[0638]

[0639] In Tables 4 and 5, the solvents, quenchers (SQ-1~SQ-4) and acid generators (PAG-1, PAG-2) are described below.

[0640] Solvent: PGMEA (Propylene Glycol Monomethyl Ether Acetate)

[0641] DAA (diacetone alcohol)

[0642] EL (ethyl lactate)

[0643] Quenching agents: SQ-1~SQ-4

[0644] [Chemistry 160]

[0645]

[0646] Acid generating agents: PAG-1, PAG-2

[0647] [Chemistry 161]

[0648]

[0649] [5] Evaluation of EUV lithography (1)

[0650] [Examples 5-1 to 5-24, Comparative Examples 5-1 to 5-8]

[0651] The chemically amplified resist compositions (R-1~R-24, CR-1~CR-8) shown in Tables 4 and 5 were spin-coated onto a Si substrate with a silicon-containing spin-coating hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Industry Co., Ltd., to a thickness of 20 nm. The substrate was pre-baked at 100°C for 60 seconds using a hot plate to obtain a resist film with a thickness of 50 nm. The aforementioned resist film was then subjected to exposure testing using an ASML EUV scanning exposure machine NXE3400 (NA 0.33, σ 0.9 / 0.6, dipole illumination), with variations in exposure amount and focus (exposure spacing: 1 mJ / cm). 2 An LS pattern with a size of 18 nm and a pitch of 36 nm was exposed on the wafer (focal spacing: 0.020 μm). After exposure, PEB was performed at the temperatures shown in Tables 6 and 7 for 60 seconds. Subsequently, immersion development was performed for 30 seconds with a 2.38% (w / w) TMAH aqueous solution, followed by rinsing with a surfactant-containing rinsing material and spin drying to obtain a positive pattern.

[0652] The LS pattern was observed using a Hitachi Advanced Technology Co., Ltd. critical dimension SEM (CG6300), and the sensitivity, EL, LWR, and collapse limit were evaluated according to the following methods. The results are shown in Tables 6 and 7.

[0653] [Sensitivity Evaluation]

[0654] Calculate the optimal exposure Eop (mJ / cm) for obtaining an LS pattern with a linewidth of 18nm and a pitch of 36nm. 2 ), and let it be the sensitivity. The smaller the value, the higher the sensitivity.

[0655] [EL Review]

[0656] The exposure amount formed within ±10% (16.2~19.8nm) of the 18nm spacing width in the aforementioned LS pattern is used to calculate the EL (unit: %) using the following formula. The larger this value, the better the performance.

[0657] EL(%) = (|E1-E2| / Eop) × 100

[0658] E1: Provides optimal exposure for LS patterns with a linewidth of 16.2nm and a pitch of 36nm.

[0659] E2: Provides optimal exposure for LS patterns with a linewidth of 19.8nm and a pitch of 36nm.

[0660] Eop: Provides optimal exposure for LS patterns with a linewidth of 18nm and a pitch of 36nm.

[0661] [LWR Evaluation]

[0662] The dimensions at 10 points along the length of the line obtained by Eop irradiation of the LS pattern are measured, and the standard deviation (σ) of the result is calculated as 3 times the value (3σ) as the LWR. The smaller this value, the more uniform the line width and roughness of the pattern can be obtained.

[0663] [Collapse Limit Assessment of Line Patterns]

[0664] The line dimensions of the aforementioned LS pattern at various exposures were measured 10 times along its length for the optimal focal point. The finest line dimension that could be obtained without collapse was taken as the collapse limit dimension. The smaller this value, the better the collapse limit.

[0665] [Table 6]

[0666]

[0667] [Table 7]

[0668]

[0669] As shown in Tables 6 and 7, the chemically amplified resist composition using a base polymer containing repeating units from the onium salt monomers of the present invention exhibits good sensitivity and excellent EL and LWR. Furthermore, the collapse limit value is small, confirming strong pattern collapse resistance even during fine pattern formation. Therefore, it is demonstrated that the chemically amplified resist composition of the present invention is suitable as a material for EUV lithography. Moreover, comparing Examples 5-1 and 5-24, even with the same polymer composition, Example 5-24, which used a polymer with narrow dispersion synthesized by RAFT polymerization, showed superior LWR results compared to Example 5-1, which used a polymer synthesized by conventional free radical polymerization.

[0670] [6] Evaluation of EUV lithography (2)

[0671] [Examples 6-1 to 6-24, Comparative Examples 6-1 to 6-8]

[0672] The chemically amplified resist compositions (R-1~R-24, CR-1~CR-8) shown in Tables 4 and 5 were spin-coated onto a Si substrate with a silicon-containing spin-coating hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd., with a film thickness of 20 nm. The substrate was pre-baked at 105°C for 60 seconds using a hot plate to obtain a resist film with a thickness of 50 nm. This resist film was then exposed 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, +20% tolerance). PEB was then applied for 60 seconds using a hot plate at the temperatures recorded in Tables 8 and 9, followed by development with a 2.38% by mass TMAH aqueous solution for 30 seconds to form a hole pattern with a size of 23 nm.

[0673] Using a Hitachi Advanced Technology Co., Ltd. critical dimension SEM (CG6300), the exposure was measured when the hole size was formed at 23 nm, and this was set as the sensitivity. The size of 50 holes at this time was then measured, and the size variation (CDU) was set as three times the standard deviation (σ) obtained from the results, multiplied by three. The results are shown in Tables 8 and 9.

[0674] [Table 8]

[0675]

[0676] [Table 9]

[0677]

[0678] The results shown in Tables 8 and 9 confirm that the chemically amplified resist composition of the present invention has good sensitivity and excellent CDU. Furthermore, comparing Examples 6-1 and 6-24, even though the polymers have the same composition, Example 6-24, which uses a polymer with a narrow dispersion synthesized by RAFT polymerization, has a better CDU than Example 6-1, which uses a polymer synthesized by conventional free radical polymerization.

[0679] [7] Defect evaluation

[0680] [Examples 7-1 to 7-24, Comparative Examples 7-1 to 7-8]

[0681] The LS pattern with a pitch of 36 nm obtained from photolithography evaluation was observed using a KLA-Tencor KLA2905 bright-field defect inspection system. The number of defects per unit area (defects / cm²) was used as the criterion. 2 The values ​​were compared. Values ​​of 5.0 and above were represented by X, values ​​of 1.0 and above but less than 5.0 were represented by △, and values ​​less than 1.0 were represented by 〇. Smaller values ​​indicate better performance. The results are shown in Tables 10 and 11.

[0682] [Table 10]

[0683]

[0684] [Table 11]

[0685]

[0686] As shown in Tables 10 and 11, Examples 7-1 to 7-24, which are chemically amplified resist compositions of the present invention, show fewer pattern defects than Comparative Examples 7-1 to 7-8.

[0687] This specification includes the following inventions.

[0688] [1]: An onium salt type monomer, characterized by the following formula (a).

[0689] [Chemistry 162]

[0690]

[0691] In the formula, R1 is a halogen atom other than iodine, a cyano group, a nitro group, or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms. R2 and R3 are hydrogen atoms or fluorine atoms, respectively. n1 is an integer from 0 to 3, n2 is an integer from 1 to 4, and n3 is an integer from 0 to 4. L1 is a single bond, ether bond, ester bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond. Q1 and Q2 are independently hydrogen atoms, saturated hydrocarbon groups with 1 to 6 carbon atoms, fluorine atoms, or fluorinated saturated hydrocarbon groups with 1 to 6 carbon atoms, respectively. Q3 and Q4 are independently hydrogen atoms, saturated hydrocarbon groups with 1 to 6 carbon atoms, fluorine atoms, or fluorinated saturated hydrocarbon groups with 1 to 6 carbon atoms, respectively. Z + It is a ium cation.

[0692] [2]: The onion salt type monomers mentioned above [1] are represented by the following formula (a1).

[0693] [Chemistry 163]

[0694]

[0695] In the formula, n1~n3, R1, L1, Q1~Q4 and Z + Same as above.

[0696] [3]: The onium salt type monomers as described in [1] or [2] above are represented by the following formula (a2).

[0697] [Chemistry 164]

[0698]

[0699] In the formula, n1~n3, R1, Q1, Q2 and Z+ Same as above.

[0700] [4]: As in any of [1] to [3] above, the onium salt type monomer, wherein Z + It is a sulfonium cation represented by the following formula (cation-1) or a monazine cation represented by the following formula (cation-2).

[0701] [Chemistry 165]

[0702]

[0703] In the formula, R ct1 ~R ct5 Each group is a hydrocarbon group with 1 to 30 carbon atoms, which may be independently composed of halogen atoms or may also contain heteroatoms. Also, R ct1 and R ct2 They can also bond to each other and form rings together with the sulfur atoms they are bonded to.

[0704] [5]: A polymer characterized by containing repeating units from any of the onium salt monomers described above [1] to [4].

[0705] [6]: The polymers described above [5] also contain repeating units represented by formula (b1) or (b2).

[0706] [Chemistry 166]

[0707]

[0708] In the formula, R A Each can be independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0709] X 1 Single bond, phenylene, naphthylene, *-C(=O)-OX 11 -or *-C(=O)-NH-X 11 - and the phenylene or naphthylene group can also be substituted by an alkoxy or halogen atom with 1 to 10 carbon atoms, which may also contain a fluorine atom. X 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms, and the saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or an lactone ring.

[0710] X 2 It is a single bond, *-C(=O)-O- or *-C(=O)-NH-.

[0711] * indicates an atomic bond with a carbon atom in the main chain.

[0712] AL 1 and AL 2 Each is an acid-labile group.

[0713] R 11 It can be a halogen atom, a cyano group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxygen 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 oxygen group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms containing heteroatoms.

[0714] a is an integer between 0 and 4.

[0715] [7]: Polymers such as those in [5] or [6] above, which also contain repeating units represented by the following formula (c1).

[0716] [Chemistry 167]

[0717]

[0718] In the formula, R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0719] 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.

[0720] R 21 It can be a halogen atom, nitro group, cyano group, or a hydrocarbon 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 group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon carbonyl group with 2 to 20 carbon atoms containing heteroatoms.

[0721] c is an integer from 1 to 4. d is an integer from 0 to 3. However, 1 ≤ c + d ≤ 5.

[0722] [8]: The polymers of any of the above [5] to [7] also contain repeating units represented by the following formula (d1).

[0723] [Chemistry 168]

[0724]

[0725] In the formula, R A It can be a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0726] Z 1 Single bond, phenylene, naphthylene, *-C(=O)-OZ 11 -or *-C(=O)-NH-Z 11- or the phenylene or naphthylene group may be substituted by an alkoxy or halogen atom with 1 to 10 carbon atoms, which may also contain a fluorine atom. * indicates an atomic bond with the carbon atom of the main chain. Z 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms, and the saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or an lactone ring.

[0727] R 31 It is a hydrogen atom, or a group containing at least one of the following structures with 1 to 20 carbon atoms: hydroxyl group (other than phenolic hydroxyl 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)-).

[0728] [9]: A chemically amplified resist composition, characterized by containing:

[0729] (A) A base polymer that contains any of the polymers described in [5] to [8] above.

[0730]

[10] : The chemically amplified resist composition as described in [9] above also contains one or more of (B) an organic solvent, (C) a quencher, (D) an acid generator, (E) a surfactant, and (F) a dissolution inhibitor.

[0731]

[11] : A method for forming a pattern, characterized by comprising the following steps:

[0732] A resist film is formed on a substrate using a chemically amplified resist composition as described in [9] or

[10] above.

[0733] The aforementioned resist film was exposed to high-energy rays, and

[0734] The previously exposed resist film was developed using a developer.

[0735]

[12] : As described in

[11] above, the high-energy rays are set as ArF excimer laser with a wavelength of 193 nm or KrF excimer laser with a wavelength of 248 nm, electron beam or extreme ultraviolet light with a wavelength of 3~15 nm.

[0736] Furthermore, the present invention is not limited to the embodiments described above. The embodiments described above are illustrative examples, and those having substantially the same structure as the technical concept described in the claims of the present invention and performing the same effects are all intended to be included within the technical scope of the present invention.

Claims

1. A bellium salt type monomer, characterized by the following: Equation (a) represents; In the formula, R1 is a halogen atom other than iodine, a cyano group, a nitro group, or a hydrocarbon group with 1 to 20 carbon atoms that may also contain heteroatoms; R2 and R3 are hydrogen atoms or fluorine atoms, respectively; n1 is an integer from 0 to 3, n2 is an integer from 1 to 4, and n3 is an integer from 0 to 4; L1 is a single bond, ether bond, ester bond, sulfonate bond, sulfonamide bond, carbonate bond, or carbamate bond; Q1 and Q2 are independently hydrogen atoms, saturated hydrocarbon groups with 1 to 6 carbon atoms, fluorine atoms, or fluorinated saturated hydrocarbon groups with 1 to 6 carbon atoms, respectively; Q3 and Q4 are independently hydrogen atoms, saturated hydrocarbon groups with 1 to 6 carbon atoms, fluorine atoms, or fluorinated saturated hydrocarbon groups with 1 to 6 carbon atoms, respectively; Z + It is a ium cation.

2. The onium salt type monomer according to claim 1, which is represented by the following formula (a1); In the formula, n1~n3, R1, L1, Q1~Q4 and Z + Same as above.

3. The onium salt type monomer according to claim 2, which is represented by the following formula (a2); In the formula, n1~n3, R1, Q1, Q2 and Z + Same as above.

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

5. A polymer characterized by containing repeating units from an onium salt monomer according to any one of claims 1 to 4.

6. The polymer according to claim 5, further comprising repeating units represented by formula (b1) or (b2); In the formula, R A Each can be independently composed of 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 - and the phenylene or naphthylene group may also be substituted by an alkoxy or halogen atom with 1 to 10 carbon atoms, which may also contain a fluorine atom; X 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms, and the saturated hydrocarbon group may also contain a hydroxyl group, an ether bond, an ester bond, or an lactone ring; 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 1 and AL 2 Each is an acid-labile group; R 11 It can be a halogen atom, a cyano group, or a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxygen 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 oxygen group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxygen carbonyl group with 2 to 20 carbon atoms containing heteroatoms. a is an integer between 0 and 4.

7. The polymer according to claim 5, further comprising a repeating unit represented by the following formula (c1); In the formula, R A It consists of hydrogen atoms, fluorine atoms, methyl groups, or trifluoromethyl groups; Y 1 For single bonds, *-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 oxygen 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 oxygen group with 2 to 20 carbon atoms containing heteroatoms, or a hydrocarbon oxygen 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.

8. The polymer according to claim 5, further comprising a repeating unit represented by the following formula (d1); In the formula, R A It consists of hydrogen atoms, fluorine atoms, methyl groups, or trifluoromethyl groups; Z 1 Single bond, phenylene, naphthylene, *-C(=O)-OZ 11 -or *-C(=O)-NH-Z 11 - or the phenylene or naphthylene group may also be substituted by an alkoxy or halogen atom containing fluorine atoms, having 1 to 10 carbon atoms; * indicates an atomic bond with the carbon atoms of the main chain; Z 11 It is a saturated hydrocarbon group, phenylene group, or naphthylene group with 1 to 10 carbon atoms, and 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 containing at least one of the following structures with 1 to 20 carbon atoms: 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)-).

9. A chemically amplified resist composition, characterized by containing: (A) A base polymer comprising the polymer according to claim 5.

10. The chemically amplified resist composition according to claim 9, further comprising one or more of (B) an organic solvent, (C) a quencher, (D) an acid generator, (E) a surfactant, and (F) a dissolution inhibitor.

11. A method for forming a pattern, characterized by comprising the following steps: A resist film is formed on a substrate using the chemically amplified resist composition according to claim 9. The resist film was exposed to high-energy rays, and The exposed resist film was developed using a developer.

12. The pattern forming method according to claim 11, wherein the high-energy ray is set as an ArF excimer laser with a wavelength of 193 nm, or 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.

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