Resist material and pattern forming method

Abstract

To provide a resist material which has high sensitivity and improved LWR and CDU regardless of whether it is positive or negative, and a pattern forming method using the same.SOLUTION: The resist material contains a bis-onium salt containing: a divalent anion which has a phenoxide anion structure substituted with an iodine atom and an arylsulfonic acid anion structure bonded to an aromatic ring of the phenoxide anion structure; and an onium cation.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resist material and a pattern forming method.

Background Art

[0002] With the increasing integration density and speed of LSIs, the miniaturization of pattern rules has been rapidly progressing. This is because the high-speed communication of 5G and the spread of artificial intelligence (AI) are advancing, and high-performance devices for processing these are required. As the most advanced miniaturization technology, mass production of 5nm node and 3nm node devices by extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm is being carried out. Furthermore, studies using EUV lithography are also underway for next-generation 2nm node devices and successive-generation 14Å nodes, and IMEC in Belgium has announced the development of 2Å devices.

[0003] With the progress of miniaturization, image blurring due to acid diffusion has become a problem. In order to ensure the resolution of fine patterns with a processing dimension of 45nm or less, it has been proposed that not only the improvement of the dissolution contrast conventionally proposed but also the control of acid diffusion is important (Non-Patent Document 1). However, since chemically amplified resist materials increase the sensitivity and contrast by acid diffusion, if the post-exposure bake (PEB) temperature is lowered or the time is shortened to suppress acid diffusion to the limit, the sensitivity and contrast will be significantly reduced.

[0004] In EUV resist materials, it is necessary to simultaneously achieve high sensitivity, high resolution, and low line width roughness (LWR). Shortening the acid diffusion distance improves LWR and dimensional uniformity (CDU), but reduces the sensitivity. For example, lowering the PEB temperature improves LWR and CDU, but reduces the sensitivity. Increasing the amount of quencher added also improves LWR and CDU, but reduces the sensitivity. It is necessary to break the trade-off relationship between sensitivity and LWR.

[0005] Resist materials have been proposed in which onium salts containing anions containing iodine or bromine atoms are added as acid generators (Patent Documents 1 to 4). The presence of iodine atoms, which have high EUV absorption, and bromine atoms, which have high ionization efficiency, increases the efficiency of decomposition of the acid generator during exposure, resulting in high sensitivity. This increases the amount of photon absorption, thereby improving physical contrast.

[0006] EUV light with a wavelength of 13.5 nm is an order of magnitude shorter than ArF excimer laser light with a wavelength of 193 nm, and therefore has high energy and is significantly affected by variations in the number of photons (Non-Patent Document 2). This has been pointed out to cause degradation of LWR (Non-Patent Document 3). In addition, with the progress of miniaturization, the influence of variations (Resist, Stochastics) in resist components (polymer, PAG, quencher) on LWR degradation has also been pointed out (Non-Patent Document 4).

[0007] A resist material containing a polymer in which a photoacid generator (PAG) and a quencher (PDQ) are bonded has been proposed (Patent Document 5). By integrating the polymer, PAG, and quencher, it is possible to suppress variations in their presence and improve LWR and CDU. Furthermore, resist materials containing an additive in which a PAG and a quencher are bonded have also been proposed (Patent Documents 6 and 7).

[0008] The health effects of perfluoroalkyl substances (PFAS) have been pointed out, and there are moves to impose restrictions on the manufacture and sale of PFAS compounds under the European REACH Act. Many compounds containing PFAS are currently used in semiconductor lithography. For example, materials containing PFAS are used in surfactants, acid generators, etc. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2018-159744 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-5224 [Patent Document 3 Japanese Patent Application Laid-Open No. 2018-25789 [Patent Document 4 Japanese Patent Application Laid-Open No. 2019-3175 [Patent Document 5 Japanese Patent Application Laid-Open No. 2022-115072 [Patent Document 6 Japanese Patent Application Laid-Open No. 2015-24989 [Patent Document 7 International Publication No. 2020 / 158313 [Non-Patent Document

[0010] [Non-Patent Document 1 SPIE Vol. 6520 65203L-1 (2007) [Non-Patent Document 2 SPIE Vol. 3331 535 (1998) [Non-Patent Document 3 SPIE Vol. 7273 727343-1 (2009) [Non-Patent Document 4 SPIE Vol. 9776 97760V-1 (2016) [Summary of the Invention [Problems to be Solved by the Invention

[0011] There is a demand for the development of a resist material that is more sensitive than conventional resist materials and can improve the LWR of line patterns and the CDU of hole patterns.

[0012] The present invention has been made in view of the above circumstances, and an object thereof is to provide a resist material that is highly sensitive and has improved LWR and CDU, whether it is a positive type or a negative type, and a pattern forming method using the same. [Means for Solving the Problems

[0013] As a result of intensive studies to achieve the above object, the present inventors have found that by using a bis-onium salt containing a divalent anion having a phenoxide anion structure substituted with an iodine atom and an arylsulfonic acid anion structure bonded to the aromatic ring of the phenoxide anion structure and an onium cation as an acid generator and a quencher, the acid generator is directly excited by radiation exposure, and the influence of the diffusion of secondary electrons is eliminated. As a result, a resist material having high sensitivity, improved LWR and CDU, high contrast, excellent resolution, and a wide process margin can be obtained, and the present invention has been completed.

[0014] That is, the present invention provides the following resist materials and pattern forming methods. 1. A resist material containing a bis-onium salt containing a divalent anion having a phenoxide anion structure substituted with an iodine atom and an arylsulfonic acid anion structure bonded to the aromatic ring of the phenoxide anion structure and an onium cation. 2. The resist material of 1, wherein the bis-onium salt is represented by the following formula (1). [Chemical formula] (In the formula, m is an integer of 1 to 4. n is an integer of 0 to 3. However, 1 ≤ m + n ≤ 4. p is an integer of 0 to 10. X 1 and X 2 are each independently a single bond, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond or a carbamate bond. R 1 is a hydrocarbyl group having 1 to 10 carbon atoms, a halogen atom other than an iodine atom, a nitro group or a cyano group, and the hydrocarbyl group may have at least one selected from a halogen atom, an oxygen atom, a sulfur atom and a nitrogen atom. R 2 is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms, and the hydrocarbylene group may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom. R3 is a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a cyano group, a nitro group, a hydroxy group, a carboxy group, an amino group, a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms, -N(R 3A )-C(=O)-R 3B 、-N(R 3A )-C(=O)-O-R 3B or -N(R 3A )-S(=O)2-R 3B , and the hydrocarbyl group, hydrocarbyloxy group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, hydrocarbylsulfonyloxy group may contain at least one selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, an amino group, an ester bond, an ether bond, a urethane bond, a urea bond, a carbonate bond, an amide bond, a sulfonic acid bond, a carbonyl group, a sulfide group, and a sulfonyl group. R 3A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and the saturated hydrocarbyl group may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. R 3B is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms or an aryl group having 6 to 12 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. Ar is a (p + 2)-valent aromatic hydrocarbon group having 6 to 16 carbon atoms. M + is a sulfonium cation or an iodonium cation.) 3. Further, a resist material of 1 or 2 containing a base polymer. 4. The resist material of 3, wherein the base polymer contains a repeating unit represented by the following formula (a1) or (a2). [Chemical formula] (In the formula, R A is independently a hydrogen atom or a methyl group. Y 1 is a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 12 carbon atoms containing at least one selected from an ester bond, an ether bond and a lactone ring, and the phenylene group, naphthylene group and linking group may have at least one selected from a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms and a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms. Y 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 are each independently an acid-labile group. R 13 is a saturated hydrocarbyl group having 1 to 4 carbon atoms, a halogen atom, a saturated hydrocarbylcarbonyl group having 2 to 5 carbon atoms, a cyano group or a saturated hydrocarbyloxycarbonyl group having 2 to 5 carbon atoms. R 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain an ether bond or an ester bond. a is an integer of 0 to 4.) 5. The resist material of 4, which is a chemically amplified positive resist material. 6. The resist material of 3, wherein the base polymer does not contain an acid-labile group. 7. The resist material of 6, which is a chemically amplified negative resist material. 8. The resist material of any one of 1 to 7, further containing an organic solvent. 9. The resist material of any one of 1 to 8, further containing a quencher. 10. The resist material of any one of 1 to 9, further containing an acid generator. 11. A resist material containing a surfactant and any one of 1 to 10. 12. A pattern forming method including a step of forming a resist film on a substrate using a resist material of any one of 1 to 11, a step of exposing the resist film with high energy rays, and a step of developing the exposed resist film using a developer. 13. The pattern forming method according to 12, wherein the high energy rays are ArF excimer laser light having a wavelength of 193 nm, KrF excimer laser light having a wavelength of 248 nm, an electron beam (EB), or EUV having a wavelength of 3 to 15 nm.

Effect of the Invention

[0015] A resist film containing a divalent anion having a phenoxide anion structure substituted with an iodine atom and an arylsulfonate anion structure bonded to the aromatic ring of the phenoxide anion structure and an onium cation is directly excited during exposure due to a large absorption of EUV light and has a characteristic of suppressing acid diffusion. Thereby, it is possible to prevent a decrease in resolution due to secondary electrons and blurring of acid diffusion. The bisonium salt is in a form in which an acid generator of an onium salt that generates sulfonic acid and a quencher of an onium salt that generates iodinated phenol are bonded and the acid generator and the quencher are always arranged at a constant distance. Therefore, by improving the above-described Resist Stochastics, it is possible to improve LWR and CDU. By having an iodine atom on the quencher side, the absorption on the quencher side is higher than that on the acid generator side, and the decomposition efficiency on the quencher side is higher. Thereby, it is possible to construct a resist material having high sensitivity and improved LWR and CDU.

Mode for Carrying Out the Invention

[0016] [Resist Material] The resist material of the present invention contains a bis-onium salt including a divalent anion having a phenoxide anion structure substituted with an iodine atom and an arylsulfonic acid anion structure bonded to the aromatic ring of the phenoxide anion structure, and an onium cation. The bis-onium salt is an acid generator-cum-quencher having both the functions of an acid generator and a quencher. The combination of the light absorption by the iodine atom, the high reactivity of the arylsulfonic acid, and the acid diffusion controllability due to the presence of the quencher always in the vicinity results in small acid diffusion and uniform diffusion distance. Thereby, LWR and CDU can be improved.

[0017] The effect of improving LWR and CDU by the bis-onium salt used in the present invention is effective in any of positive pattern formation and negative pattern formation by alkaline aqueous solution development, and negative pattern formation in organic solvent development.

[0018] [Bis-onium salt] As the bis-onium salt, those represented by the following formula (1) are preferable. [Chemical formula]

[0019] In formula (1), m is an integer of 1 to 4. n is an integer of 0 to 3. However, 1 ≤ m + n ≤ 4. p is an integer of 0 to 10.

[0020] In formula (1), X 1 and X 2 are each independently a single bond, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond or a carbamate bond. Among these, as X 1 , a single bond, an ether bond, an ester bond or a sulfonic acid ester bond is preferable, and as X 2 , a single bond, an ether bond or an ester bond is preferable.

[0021] In formula (1), R 1is a hydrocarbyl group having 1 to 10 carbon atoms, a halogen atom other than an iodine atom, a nitro group or a cyano group, and the hydrocarbyl group may have at least one selected from halogen atoms, oxygen atoms, sulfur atoms and nitrogen atoms.

[0022] R 1 Specific examples of the halogen atom represented by are a fluorine atom, a chlorine atom, a bromine atom and the like. R 1 The hydrocarbyl group represented by may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 10 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group; cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms such as cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group, norbornyl group, adamantyl group; alkenyl groups having 2 to 10 carbon atoms such as vinyl group, propenyl group, butenyl group, hexenyl group; alkynyl groups having 2 to 10 carbon atoms such as ethynyl group, propynyl group, butynyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 10 carbon atoms such as cyclohexenyl group, norbornenyl group; aryl groups having 6 to 10 carbon atoms such as phenyl group, methylphenyl group, ethylphenyl group, n-propylphenyl group, isopropylphenyl group, n-butylphenyl group, isobutylphenyl group, sec-butylphenyl group, tert-butylphenyl group, naphthyl group; aralkyl groups having 7 to 10 carbon atoms such as benzyl group, phenethyl group; groups obtained by combining these and the like.

[0023] In formula (1), R 2 is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms, and the hydrocarbylene group may contain at least one selected from oxygen atoms, nitrogen atoms, sulfur atoms and halogen atoms.

[0024] R 2The hydrocarbylene group represented by may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include C1-C40 alkanediyl groups such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, 1-methylethane-1,2-diyl group, 1-ethylethane-1,2-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-1,3-diyl group, 2-methylpropane-1,1-diyl group, butane-1,3-diyl group, butane-1,4-diyl group, butane-2,3-diyl group, 1,1-dimethylpropane-1,3-diyl group, 2,2-dimethylpropane-1,3-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group, octadecane-1,18-diyl group, nonadecane-1,19-diyl group, eicosane-1,20-diyl group; C3-C40 cyclic saturated hydrocarbylene groups such as cyclopentanediyl group, cyclohexanediyl group, bicyclo[2.2.2]octanediy group, norbornanediyl group, adamantanediyl group; C2-C40 alkenediyl groups such as ethenediyl group, propenediyl group, butenediyl group; C2-C40 alkynediyl groups such as ethynediyl group, propynediyl group, butynediyl group; C3-C40 cyclic unsaturated aliphatic hydrocarbylene groups such as cyclohexenediyl group, bicyclo[2.2.2]octenediyl group, norbornenediyl group; C6-C40 arylene groups such as phenylene group, methylphenylene group, ethylphenylene group, n-propylphenylene group, isopropylphenylene group, n-butylphenylene group, isobutylphenylene group, sec-butylphenylene group, tert-butylphenylene group, naphthylene group, methylnaphthylene group, ethylnaphthylene group, 9,10-dihydro-9,10-ethanoanthracenediyl; groups obtained by combining these, and the like.

[0025] In formula (1), R 3 is a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a cyano group, a nitro group, a hydroxy group, a carboxy group, an amino group, a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms, -N(R 3A )-C(=O)-R 3B , -N(R 3A )-C(=O)-O-R 3B or -N(R 3A )-S(=O)2-R 3B , and the hydrocarbyl group, hydrocarbyloxy group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, hydrocarbylsulfonyloxy group may contain at least one selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, an amino group, an ester bond, an ether bond, a urethane bond, a urea bond, a carbonate bond, an amide bond, a sulfonic acid bond, a carbonyl group, a sulfide group and a sulfonyl group. R 3A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and the saturated hydrocarbyl group may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. R 3B is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms or an aryl group having 6 to 12 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms.

[0026] R 3The hydrocarbyl groups represented by , as well as the hydrocarbyl moieties of hydrocarbyloxy groups, hydrocarbyloxycarbonyl groups, hydrocarbylcarbonyloxy groups and hydrocarbylsulfonyloxy groups, may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group; cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms such as cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group, norbornyl group, adamantyl group; alkenyl groups having 2 to 20 carbon atoms such as vinyl group, propenyl group, butenyl group, hexenyl group; alkynyl groups having 2 to 20 carbon atoms such as ethynyl group, propynyl group, butynyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 20 carbon atoms such as cyclohexenyl group, norbornenyl group; aryl groups having 6 to 20 carbon atoms such as phenyl group, methylphenyl group, ethylphenyl group, n-propylphenyl group, isopropylphenyl group, n-butylphenyl group, isobutylphenyl group, sec-butylphenyl group, tert-butylphenyl group, naphthyl group, methylnaphthyl group, ethylnaphthyl group, n-propylnaphthyl group, isopropylnaphthyl group, n-butylnaphthyl group, isobutylnaphthyl group, sec-butylnaphthyl group, tert-butylnaphthyl group; aralkyl groups having 7 to 20 carbon atoms such as benzyl group, phenethyl group; and groups obtained by combining these, etc.

[0027] In formula (1), Ar is a (p + 2)-valent aromatic hydrocarbon group having 6 to 16 carbon atoms. Specific examples of the aromatic hydrocarbon group include groups obtained by eliminating (p + 2) hydrogen atoms from aromatic hydrocarbons such as benzene, naphthalene, anthracene, pyrene.

[0028] Specific examples of the anion of the bisonium salt include, but are not limited to, those shown below. [Chemical formula]

[0029] [Chemical formula]

[0030] [Chemical formula]

[0031] [Chemical formula]

[0032] [Chemical formula]

[0033] [Chemical formula]

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[0060] [Chemical formula]

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[0063] [Chemical formula]

[0064] [Chemical formula]

[0065] [Chemical formula]

[0066] [Chemical formula]

[0067] In formula (1), M + is a sulfonium cation or an iodonium cation. The two Ms + may be such that one is a sulfonium cation and the other is an iodonium cation, both may be sulfonium cations, or both may be iodonium cations. When both of the two Ms + are sulfonium cations, they may be the same as or different from each other. Also, the two Ms +are iodonium cations, they may be the same or different.

[0068] The sulfonium cation is preferably one represented by the following formula (2), and the iodonium cation is preferably one represented by the following formula (3). [ka]

[0069] In formulas (2) and (3), R 4 ~R 8 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom.

[0070] R 4 ~R 8 Specific examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0071] R 4 ~R 8The hydrocarbyl group having 1 to 20 carbon atoms represented by may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group; cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms such as cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group, norbornyl group, adamantyl group; alkenyl groups having 2 to 20 carbon atoms such as vinyl group, propenyl group, butenyl group, hexenyl group; alkynyl groups having 2 to 20 carbon atoms such as ethynyl group, propynyl group, butynyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 20 carbon atoms such as cyclohexenyl group, norbornenyl group; aryl groups having 6 to 20 carbon atoms such as phenyl group, methylphenyl group, ethylphenyl group, n-propylphenyl group, isopropylphenyl group, n-butylphenyl group, isobutylphenyl group, sec-butylphenyl group, tert-butylphenyl group, naphthyl group, methylnaphthyl group, ethylnaphthyl group, n-propylnaphthyl group, isopropylnaphthyl group, n-butylnaphthyl group, isobutylnaphthyl group, sec-butylnaphthyl group, tert-butylnaphthyl group; aralkyl groups having 7 to 20 carbon atoms such as benzyl group, phenethyl group; groups obtained by combining these, and the like.

[0072] Also, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and a part of -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, it may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a mercapto group, a pentafluorosulfanyl group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0073] Also, R 4 and R 5 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. At this time, the ring is preferably one having the structure shown below.

Chemical formula

[0074] M + Specific examples of the sulfonium cation represented by are as follows, but are not limited thereto.

Chemical formula

[0075]

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[0109] M + Specific examples of the iodonium cation represented by [M] + include, but are not limited to, those shown below. [ka]

[0110] [ka]

[0111] Examples of methods for synthesizing the bis-onium salt include a method of salt exchange between a sulfonium salt or iodonium salt containing a halide anion and a diammonium salt containing a divalent anion having a phenoxide anion structure substituted with an iodine atom and an arylsulfonate anion structure bonded to the aromatic ring of the phenoxide anion structure.

[0112] In the resist material of the present invention, the content of the bis-onium salt is preferably 0.01 to 1000 parts by mass, more preferably 0.05 to 500 parts by mass, per 100 parts by mass of the base polymer described below, from the viewpoints of sensitivity and acid diffusion suppression effect.

[0113] [Base polymer] In the case of a positive resist material, the base polymer contained in the resist material of the present invention contains a repeating unit having an acid labile group. The repeating unit having an acid labile group is preferably a repeating unit represented by the following formula (a1) (hereinafter also referred to as repeating unit a1) or a repeating unit represented by the following formula (a2) (hereinafter also referred to as repeating unit a2). [ka]

[0114] In formulas (a1) and (a2), R A are each independently a hydrogen atom or a methyl group. 1is a linking group having 1 to 12 carbon atoms and containing at least one selected from a single bond, a phenylene group or a naphthylene group, or an ester bond, an ether bond and a lactone ring, and the phenylene group, the naphthylene group and the linking group may have at least one selected from a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms and a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms. Y 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 are each independently an acid-labile group. R 13 is a saturated hydrocarbyl group having 1 to 4 carbon atoms, a halogen atom, a saturated hydrocarbylcarbonyl group having 2 to 5 carbon atoms, a cyano group or a saturated hydrocarbyloxycarbonyl group having 2 to 5 carbon atoms. R 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain an ether bond or an ester bond. a is an integer of 0 to 4.

[0115] Specific examples of the monomer that gives the repeating unit a1 include, but are not limited to, those shown below. In the following formulas, R A and R 11 are the same as those described above.

Chemical formula

[0116]

Chemical formula

[0117]

Chemical formula

[0118] Specific examples of the monomer that gives the repeating unit a2 include, but are not limited to, those shown below. In the following formulas, R A and R 12is the same as described above. [Chemical formula]

[0119] In the repeating units a1 and a2, R 11 and R 12 Examples of the acid-labile groups represented by R and R include those described in JP-A-2013-80033 and JP-A-2013-83821.

[0120] Typically, specific examples of the acid-labile group include those represented by any of the following formulas (AL-1) to (AL-3). [Chemical formula] (In the formula, the dashed line represents a bond.)

[0121] In formulas (AL-1) and (AL-2), R L1 and R L2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms, and may contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, and a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 40 carbon atoms is preferable, and a saturated hydrocarbyl group having 1 to 20 carbon atoms is more preferable.

[0122] In formula (AL-1), b is an integer of 0 to 10, and an integer of 1 to 5 is preferable.

[0123] In formula (AL-2), R L3 and R L4 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, and a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 20 carbon atoms is preferable. Also, R L2 , RL3 and R L4 Any two of them may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atoms to which they are bonded or carbon atoms and oxygen atoms. As the ring, a ring having 4 to 16 carbon atoms is preferable, and an alicyclic ring is particularly preferable.

[0124] In formula (AL-3), R L5 , R L6 and R L7 are each independently a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 20 carbon atoms is preferable. Also, any two of R L5 , R L6 and R L7 may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atoms to which they are bonded. As the ring, a ring having 4 to 16 carbon atoms is preferable, and an alicyclic ring is particularly preferable.

[0125] The base polymer may contain a repeating unit b containing a phenolic hydroxy group as an adhesion group. Specific examples of the monomer that gives the repeating unit b include, but are not limited to, those shown below. In the following formula, R A is the same as described above.

Chemical formula

[0126] The base polymer may contain a repeating unit c containing a hydroxy group other than a phenolic hydroxy group, a lactone ring, a sultone ring, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonyl group, a sulfonyl group, a cyano group, or a carboxy group as another adhesion group. Specific examples of the monomer that gives the repeating unit c include, but are not limited to, those shown below. In the following formula, R A is the same as described above. [Chemical]

[0127] [Chemical]

[0128] [Chemical]

[0129] [Chemical]

[0130] [Chemical]

[0131] [Chemical]

[0132] [Chemical]

[0133] [Chemical]

[0134] The base polymer may contain a repeating unit d derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene, or a derivative thereof. Specific examples of the monomer that gives the repeating unit d include, but are not limited to, those shown below. [Chemical]

[0135] The base polymer may contain a repeating unit e derived from styrene, vinylnaphthalene, vinylanthracene, vinylpyrene, methylene indane, vinylpyridine or vinylcarbazole.

[0136] The base polymer may contain a repeating unit f derived from an onium salt containing a polymerizable unsaturated bond. Specific examples of preferred repeating unit f include a repeating unit represented by the following formula (f1) (hereinafter also referred to as repeating unit f1), a repeating unit represented by the following formula (f2) (hereinafter also referred to as repeating unit f2), a repeating unit represented by the following formula (f3) (hereinafter also referred to as repeating unit f3), a repeating unit represented by the following formula (f4) (hereinafter also referred to as repeating unit f4), and a repeating unit represented by the following formula (f5) (hereinafter also referred to as repeating unit f5). Note that the repeating units f1 to f5 may be used alone or in combination of two or more.

Chemical formula

[0137] In formulas (f1) to (f5), R A is independently a hydrogen atom or a methyl group.

[0138] In formulas (f1) to (f3), Z 1 is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or -O-Z 11 -, -C(=O)-O-Z 11 - or -C(=O)-NH-Z 11 -. Z 11 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 2 is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(=O)-O-, -Z31 -O- or -Z 31 is -O-C(=O)-. Z 31 Z is an aliphatic hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, an iodine atom or a bromine atom. Z 4 Z is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group or a carbonyl group. Z 5 Z is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -O-Z 51 -, -C(=O)-O-Z 51 - or -C(=O)-NH-Z 51 -. Z 51 Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom or a hydroxy group. Incidentally, Z 1 Z 11 Z 31 and Z 51 The aliphatic hydrocarbylene group represented by Z may be saturated or unsaturated, and may be linear, branched or cyclic.

[0139] In formulas (f4) and (f5), Z 6 is a single bond, a phenylene group, a naphthylene ring, an ester bond or an amide bond.

[0140] In formula (f4), Z 7A is a single bond or a divalent organic group having 1 to 24 carbon atoms, and may have at least one selected from a halogen atom, an oxygen atom, a nitrogen atom and a sulfur atom.

[0141] Z 7AThe divalent organic group represented by may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include C1-C24 hydrocarbylene groups in which some or all of the hydrogen atoms are substituted with iodine atoms or bromine atoms. Specific examples of the C1-C24 hydrocarbylene group include alkane diyl groups such as methane diyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group, octadecane-1,18-diyl group, nonadecane-1,19-diyl group, eicosane-1,20-diyl group; cyclic saturated hydrocarbylene groups such as cyclopentane diyl group, methylcyclopentane diyl group, dimethylcyclopentane diyl group, trimethylcyclopentane diyl group, tetramethylcyclopentane diyl group, cyclohexane diyl group, methylcyclohexane diyl group, dimethylcyclohexane diyl group, trimethylcyclohexane diyl group, tetramethylcyclohexane diyl group, norbornane diyl group, adamantane diyl group; arylene groups such as phenylene group, methylphenylene group, ethylphenylene group, n-propylphenylene group, isopropylphenylene group, n-butylphenylene group, isobutylphenylene group, sec-butylphenylene group, tert-butylphenylene group, naphthylene group, methylnaphthylene group, ethylnaphthylene group, n-propylnaphthylene group, isopropylnaphthylene group, n-butylnaphthylene group, isobutylnaphthylene group, sec-butylnaphthylene group, tert-butylnaphthylene group, biphenyl diyl group, methylbiphenyl diyl group, dimethylbiphenyl diyl group; groups obtained by combining these, etc. are included. Also, Z 7A Some or all of the hydrogen atoms of may be substituted with a group containing at least one selected from oxygen atoms, nitrogen atoms and sulfur atoms, and Z7A Part of the -CH2- may be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and as a result, it may contain a hydroxy group, an ester bond, an ether bond, an amide bond, a carbamate bond, a urea bond, etc.

[0142] In formula (f5), Z 7B is a monovalent organic group having 1 to 10 carbon atoms and may have at least one selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom.

[0143] Z 7BThe monovalent organic group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include hydrocarbyl groups having 1 to 10 carbon atoms in which part or all of the hydrogen atoms are substituted with iodine atoms or bromine atoms. Specific examples of the hydrocarbyl group having 1 to 10 carbon atoms include alkyl groups having 1 to 10 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, sec-pentyl group, 3-pentyl group, tert-pentyl group, neopentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group; cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group, cyclopropylmethyl group, cyclopropylethyl group, cyclobutylmethyl group, cyclobutylethyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclohexylmethyl group, cyclohexylethyl group, methylcyclopropyl group, methylcyclobutyl group, methylcyclopentyl group, methylcyclohexyl group, ethylcyclopropyl group, ethylcyclobutyl group, ethylcyclopentyl group, ethylcyclohexyl group; alkenyl groups having 2 to 10 carbon atoms such as vinyl group, 1-propenyl group, 2-propenyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, nonenyl group, decenyl group; alkynyl groups having 2 to 10 carbon atoms such as ethynyl group, propynyl group, butynyl group, pentynyl group, hexynyl group, heptynyl group, octynyl group, nonynyl group, decynyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 10 carbon atoms such as cyclopentenyl group, cyclohexenyl group, methylcyclopentenyl group, methylcyclohexenyl group, ethylcyclopentenyl group, ethylcyclohexenyl group, norbornenyl group; aryl groups having 6 to 10 carbon atoms such as phenyl group, methylphenyl group, ethylphenyl group, n-propylphenyl group, isopropylphenyl group, n-butylphenyl group, isobutylphenyl group, sec-butylphenyl group, tert-butylphenyl group, naphthyl group; aralkyl groups having 7 to 10 carbon atoms such as benzyl group, phenethyl group, phenylpropyl group, phenylbutyl group; groups obtained by combining these, and the like.Also, Z. 7B Some or all of the hydrogen atoms of 7B may be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and Z 7B Some of the -CH2- of 7B may be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and as a result, it may contain a hydroxy group, an ester bond, an ether bond, an amide bond, a carbamate bond, a urea bond, etc.

[0144] In formulas (f4) and (f5), Z 8 is a single bond, an ether bond, an ester bond, a thioether bond, or an alkanediyl group having 1 to 6 carbon atoms.

[0145] In formula (f5), Z 9 is a trivalent organic group having 1 to 12 carbon atoms, and may have at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom. The trivalent organic group represented by Z 9 may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include a group obtained by removing one more hydrogen atom from a hydrocarbylene group having 1 to 12 carbon atoms. Specific examples of the hydrocarbylene group having 1 to 12 carbon atoms include those having 1 to 12 carbon atoms among the hydrocarbylene groups having 1 to 24 carbon atoms described above. Also, some or all of the hydrogen atoms of Z 9 may be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and some of the -CH2- of Z 9 may be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and as a result, it may contain a hydroxy group, an ester bond, an ether bond, an amide bond, a carbamate bond, a urea bond, etc.

[0146] In formulas (f1) to (f5), R 21 ~R 25is independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include those exemplified as the hydrocarbyl groups represented by R 4 ~R 8 in the descriptions of Formulas (2) and (3). Further, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc. As a result, it may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. Furthermore, R 23 and R 24 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. At this time, specific examples of the ring include those similar to those exemplified as the rings that can be formed by R 4 and R 5 being bonded to each other to form a ring together with the sulfur atom to which they are bonded in the description of Formula (2).

[0147] In Formulas (f4) and (f5), R 26 is independently a saturated hydrocarbyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a fluorine atom, an iodine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group or a nitro group.

[0148] In Formulas (f4) and (f5), the circular R is a (j + 2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. Specific examples of the (j + 2)-valent aromatic hydrocarbon group include groups obtained by eliminating (j + 2) hydrogen atoms from aromatic hydrocarbons such as benzene and naphthalene.

[0149] In formulas (f4) and (f5), j is, independently of each other, an integer of 0 to 5.

[0150] In formula (f1), M - is a non-nucleophilic counter ion. Specific examples of the non-nucleophilic counter ion include halide ions such as chloride ion and bromide ion, fluoroalkyl sulfonate ions such as triflate ion, 1,1,1-trifluoroethanesulfonate ion, and nonafluorobutanesulfonate ion, aryl sulfonate ions such as tosylate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion, and 1,2,3,4,5-pentafluorobenzenesulfonate ion, alkyl sulfonate ions such as mesylate ion and butanesulfonate ion, imide ions such as bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion, and bis(perfluorobutylsulfonyl)imide ion, and methide ions such as tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0151] Specific examples of the non-nucleophilic counter ion further include sulfonate ions in which the α-position is substituted with a fluorine atom represented by the following formula (f1-1), sulfonate ions in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group represented by the following formula (f1-2), and the like. [Chemical formula]

[0152] In formula (f1-1), R 31 is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain at least one selected from an ether bond, an ester bond, a carbonyl group, a lactone ring, and a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (1A') described later.fa1 Those similar to those exemplified as the hydrocarbyl group represented by are mentioned.

[0153] In formula (f1-2), R 32 is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms or a hydrocarbylcarbonyl group having 2 to 30 carbon atoms, and the hydrocarbyl group and the hydrocarbylcarbonyl group may contain at least one selected from an ether bond, an ester bond, a carbonyl group, and a lactone ring. The hydrocarbyl moiety of the hydrocarbyl group and the hydrocarbylcarbonyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those similar to those exemplified as the hydrocarbyl group represented by R in formula (1A') described later. fa1 Those similar to those exemplified as the hydrocarbyl group represented by are mentioned.

[0154] Specific examples of the cation of the monomer that gives the repeating unit f1 include, but are not limited to, those shown below. In the following formulas, R A is the same as described above.

Chemical formula

[0155] Specific examples of the cation of the repeating units f2 to f5 include those similar to those exemplified as the cation of the onium salt represented by formula (1).

[0156] Specific examples of the anion of the monomer that gives the repeating unit f2 include, but are not limited to, those shown below. In the following formulas, R A is the same as described above.

Chemical formula

[0157]

Chemical formula

[0158] [Chemistry]

[0159] [Chemistry]

[0160] [Chemistry]

[0161] [Chemistry]

[0162] [Chemistry]

[0163] [Chemistry]

[0164] [Chemistry]

[0165] [Chemistry]

[0166] [Chemistry]

[0167] [Chemistry]

[0168] [Chemistry]

[0169]

Chem.

[0170]

Chem.

[0171] Specific examples of the anion of the monomer that gives the repeating unit f3 include, but are not limited to, those shown below. In the following formulas, R A is the same as described above.

Chem.

[0172] Specific examples of the anion of the monomer that gives the repeating unit f4 or f5 include, but are not limited to, those shown below. In the following formulas, R A and X BI are the same as described above.

Chem.

[0173]

Chem.

[0174]

Chem.

[0175]

Chem.

[0176]

Chem.

[0177]

Chem.

[0178]

Chem.

[0179]

Chem.

[0180]

Chem.

[0181]

Chem.

[0182]

Chem.

[0183]

Chem.

[0184]

Chem.

[0185]

Chem.

[0186]

Chem.

[0187]

Chem.

[0188]

change

[0189]

change

[0190]

change

[0191]

change

[0192]

change

[0193]

change

[0194]

change

[0195]

change

[0196]

change

[0197] The repeating units f1 to f5 function as an acid generator. By bonding the acid generator to the polymer main chain, acid diffusion can be reduced, and a decrease in resolution due to blurring of acid diffusion can be prevented. In addition, the LWR and CDU are improved by the uniform dispersion of the acid generator.

[0198] The base polymer for the positive resist material essentially requires a repeating unit a1 or a2 containing an acid-labile group. In this case, the content ratios of the repeating units a1, a2, b, c, d, e, and f are preferably 0 ≦ a1 < 1.0, 0 ≦ a2 < 1.0, 0 < a1 + a2 < 1.0, 0 ≦ b ≦ 0.9, 0 ≦ c ≦ 0.9, 0 ≦ d ≦ 0.8, 0 ≦ e ≦ 0.8, and 0 ≦ f ≦ 0.5, more preferably 0 ≦ a1 ≦ 0.9, 0 ≦ a2 ≦ 0.9, 0.1 ≦ a1 + a2 ≦ 0.9, 0 ≦ b ≦ 0.8, 0 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.7, 0 ≦ e ≦ 0.7, and 0 ≦ f ≦ 0.4, and still more preferably 0 ≦ a1 ≦ 0.8, 0 ≦ a2 ≦ 0.8, 0.1 ≦ a1 + a2 ≦ 0.8, 0 ≦ b ≦ 0.75, 0 ≦ c ≦ 0.75, 0 ≦ d ≦ 0.6, 0 ≦ e ≦ 0.6, and 0 ≦ f ≦ 0.3. When the repeating unit f is at least one selected from the repeating units f1 to f5, f = f1 + f2 + f3 + f4 + f5. Also, a1 + a2 + b + c + d + e + f = 1.0.

[0199] On the other hand, the base polymer for the negative resist material does not necessarily require an acid-labile group. Examples of such a base polymer include those containing the repeating unit b and optionally further containing the repeating units c, d, e, and / or f. The content ratios of these repeating units are preferably 0 < b ≦ 1.0, 0 ≦ c ≦ 0.9, 0 ≦ d ≦ 0.8, 0 ≦ e ≦ 0.8, and 0 ≦ f ≦ 0.5, more preferably 0.2 ≦ b ≦ 1.0, 0 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.7, 0 ≦ e ≦ 0.7, and 0 ≦ f ≦ 0.4, and still more preferably 0.3 ≦ b ≦ 1.0, 0 ≦ c ≦ 0.75, 0 ≦ d ≦ 0.6, 0 ≦ e ≦ 0.6, and 0 ≦ f ≦ 0.3. When the repeating unit f is at least one selected from the repeating units f1 to f5, f = f1 + f2 + f3 + f4 + f5. Also, b + c + d + e + f = 1.0.

[0200] As a method for synthesizing the base polymer, for example, a method of adding a radical polymerization initiator to a monomer that provides the repeating unit described above in an organic solvent and heating to perform polymerization can be mentioned.

[0201] Specific examples of the organic solvent used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, dioxane, and the like. Specific examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, lauroyl peroxide, and the like. The temperature during polymerization is preferably 50 to 80 °C. The reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

[0202] When copolymerizing a monomer containing a hydroxy group, the hydroxy group may be substituted with an acetal group that is easily deprotected by an acid such as an ethoxyethoxy group during polymerization and then deprotected with a weak acid and water after polymerization, or it may be substituted with an acetyl group, a formyl group, a pivaloyl group, etc. and then subjected to alkaline hydrolysis after polymerization.

[0203] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and the acetoxy group may be deprotected by the above-mentioned alkaline hydrolysis after polymerization to obtain hydroxystyrene or hydroxyvinylnaphthalene.

[0204] As the base during alkaline hydrolysis, aqueous ammonia, triethylamine, etc. can be used. Also, the reaction temperature is preferably -20 to 100 °C, more preferably 0 to 60 °C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0205] The base polymer preferably has a polystyrene-reduced weight average molecular weight (Mw) of 1,000 to 500,000, more preferably 2,000 to 30,000, as determined by gel permeation chromatography (GPC) using THF as a solvent. When Mw is within the above range, the heat resistance and solubility in an alkaline developer of the resist film are good.

[0206] Furthermore, when the molecular weight distribution (Mw / Mn) of the base polymer is broad, there are low molecular weight and high molecular weight polymers, so there is a risk that foreign matter may be seen on the pattern or the pattern shape may deteriorate after exposure. As the pattern rules are miniaturized, the influence of Mw and Mw / Mn tends to increase. Therefore, in order to obtain a resist material suitably used for fine pattern dimensions, the Mw / Mn of the base polymer is preferably narrowly dispersed at 1.0 to 2.0, particularly 1.0 to 1.5.

[0207] The base polymer may contain two or more polymers having different composition ratios, Mw, and Mw / Mn.

[0208] [Organic solvent] The resist material of the present invention may contain an organic solvent. The organic solvent is not particularly limited as long as each of the above-described components and each of the components described below can be dissolved therein. Specific examples of the organic solvent include those described in paragraphs

[0144] to

[0145] of JP-A-2008-111103, such as ketones like cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, 2-heptanone; alcohols like 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, diacetone alcohol; ethers like propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether; esters like propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol monotert-butyl ether acetate; lactones like γ-butyrolactone, etc.

[0209] In the resist material of the present invention, the content of the organic solvent is preferably 100 to 10,000 parts by mass, more preferably 200 to 8,000 parts by mass, based on 100 parts by mass of the base polymer. The organic solvent may be used alone or in combination of two or more.

[0210] [Quencher] The resist material of the present invention may contain a quencher. Note that the quencher means a compound that can prevent the diffusion to the unexposed part by trapping the acid generated from the acid generator in the resist material.

[0211] Examples of the quencher include conventional basic compounds. Specific examples of the conventional basic compounds include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxy group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, carbamates, and the like. In particular, primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103, particularly amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonic acid ester bond, or compounds having a carbamate bond described in Japanese Patent No. 3,790,649 are preferable. By adding such a basic compound, for example, the acid diffusion rate in the resist film can be further suppressed or the shape can be corrected.

[0212] In addition, examples of the quencher include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids, carboxylic acids, or fluorinated alkoxides in which the α-position is not fluorinated, as described in JP-A-2008-158339. Sulfonic acids, imidic acids, or methidic acids in which the α-position is fluorinated are necessary for deprotecting the acid-labile group of the carboxylic acid ester, but sulfonic acids, carboxylic acids, or fluorinated alcohols in which the α-position is not fluorinated are released by salt exchange with the onium salt. Sulfonic acids, carboxylic acids, and fluorinated alcohols in which the α-position is not fluorinated do not cause a deprotection reaction and thus function as a quencher.

[0213] Specific examples of such a quencher include, for example, a compound represented by the following formula (4) (onium salt of a sulfonic acid in which the α-position is not fluorinated), a compound represented by the following formula (5) (onium salt of a carboxylic acid), and a compound represented by the following formula (6) (onium salt of an alkoxide).

Chemical formula

[0214] In formula (4), R 101 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hydrogen atom or a heteroatom, provided that a hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is excluded from those substituted with a fluorine atom or a fluoroalkyl group.

[0215] R 101 The hydrocarbyl group having 1 to 40 carbon atoms represented by may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 40 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, tert-pentyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group; cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms such as cyclopentyl group, cyclohexyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclopentylbutyl group, cyclohexylmethyl group, cyclohexylethyl group, cyclohexylbutyl group, norbornyl group, tricyclo[5.2.1.0 2,6 decyl group, adamantyl group, adamantylmethyl group; alkenyl groups having 2 to 40 carbon atoms such as vinyl group, allyl group, propenyl group, butenyl group, hexenyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 40 carbon atoms such as cyclohexenyl group; aryl groups having 6 to 40 carbon atoms such as phenyl group, naphthyl group, alkylphenyl group (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-n-butylphenyl group, etc.), di- or trialkylphenyl group (2,4-dimethylphenyl group, 2,4,6-triisopropylphenyl group, etc.), alkylnaphthyl group (methylnaphthyl group, ethylnaphthyl group, etc.), dialkylnaphthyl group (dimethylnaphthyl group, diethylnaphthyl group, etc.); aralkyl groups having 7 to 40 carbon atoms such as benzyl group, (1-phenylethyl group, 2-phenylethyl group, etc.).

[0216] Also, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and a part of -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, it may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. Specific examples of the hydrocarbyl group containing a heteroatom include heteroaryl groups such as a thienyl group; alkoxyphenyl groups such as a 4-hydroxyphenyl group, a 4-methoxyphenyl group, a 3-methoxyphenyl group, a 2-methoxyphenyl group, a 4-ethoxyphenyl group, a 4-tert-butoxyphenyl group, and a 3-tert-butoxyphenyl group; alkoxynaphthyl groups such as a methoxynaphthyl group, an ethoxynaphthyl group, an n-propoxynaphthyl group, and an n-butoxynaphthyl group; dialkoxynaphthyl groups such as a dimethoxynaphthyl group and a diethoxynaphthyl group; and aryloxoalkyl groups such as a 2-aryl-2-oxoethyl group such as a 2-phenyl-2-oxoethyl group, a 2-(1-naphthyl)-2-oxoethyl group, and a 2-(2-naphthyl)-2-oxoethyl group.

[0217] In formula (5), R 102 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. Specific examples of the hydrocarbyl group represented by R 102 are the same as those exemplified as the hydrocarbyl group represented by R 101 In addition, other specific examples include fluorinated alkyl groups such as a trifluoromethyl group, a trifluoroethyl group, a 2,2,2-trifluoro-1-methyl-1-hydroxyethyl group, and a 2,2,2-trifluoro-1-(trifluoromethyl)-1-hydroxyethyl group; and fluorinated aryl groups such as a pentafluorophenyl group and a 4-trifluoromethylphenyl group.

[0218] In formula (6), R 103is a saturated hydrocarbyl group having 1 to 8 carbon atoms and at least 3 fluorine atoms or an aryl group having 6 to 10 carbon atoms and at least 3 fluorine atoms, and may contain a nitro group.

[0219] In formulas (4), (5) and (6), Mq + is an onium cation. As the onium cation, a sulfonium cation, an iodonium cation or an ammonium cation is preferable, and a sulfonium cation is more preferable. Specific examples of the sulfonium cation include those exemplified as the sulfonium cation represented by M + in the description of formula (1).

[0220] As the quencher, a sulfonium salt of an iodinated benzene ring-containing carboxylic acid represented by the following formula (7) can also be preferably used. [Chemical formula]

[0221] In formula (7), x is an integer of 1 to 5. y is an integer of 0 to 3. z is an integer of 1 to 3.

[0222] In formula (7), R 111 is a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms or a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms, in which part or all of the hydrogen atoms may be substituted with halogen atoms, or —N(R 111A )—C(═O)—R 111B or —N(R 111A )—C(═O)—O—R 111B . R 111A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 111Bis a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms. When y and / or z is 2 or more, each R 111 may be the same as or different from each other.

[0223] In formula (7), L 1 is a single bond or a (z + 1)-valent linking group having 1 to 20 carbon atoms, and may contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxy group, and a carboxy group. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, and saturated hydrocarbylsulfonyloxy group may be linear, branched, or cyclic.

[0224] In formula (7), R 112 , R 113 and R 114 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same ones as those exemplified as the hydrocarbyl groups represented by R 4 to R 8 in the descriptions of formulas (2) and (3).

[0225] Specific examples of the compound represented by formula (7) include those described in JP-A-2017-219836 and JP-A-2021-91666.

[0226] As another example of the quencher, a polymer type quencher described in JP-A-2008-239918 can be mentioned. This enhances the rectangularity of the resist pattern by orienting on the resist film surface. The polymer type quencher also has an effect of preventing film loss of the pattern and rounding of the pattern top when a protective film for liquid immersion exposure is applied.

[0227] Furthermore, betaine-type sulfonium salts described in Japanese Patent No. 6848776 and JP-A-2020-37544, methide acids not containing a fluorine atom described in JP-A-2020-55797, sulfonium salts of sulfonamides described in Japanese Patent No. 5807552, sulfonium salts of sulfonamides containing an iodine atom described in JP-A-2019-211751, phenol, halogen, and an acid generator that generates carbonic acid can also be used as a quencher.

[0228] When the resist material of the present invention contains the quencher, its content is preferably 0 to 5 parts by mass, more preferably 0 to 4 parts by mass, per 100 parts by mass of the base polymer. The quencher may be used alone or in combination of two or more.

[0229] [Other Components] In addition to the components described above, an acid generator other than the salt represented by the formula (1) (hereinafter referred to as other acid generator), a surfactant, a dissolution inhibitor, a crosslinking agent, a water repellency improver, acetylene alcohols, etc. may be included.

[0230] Examples of the other acid generator include compounds (photoacid generators) that generate an acid upon exposure to actinic rays or radiation. As components of the photoacid generator, any compound that generates an acid upon irradiation with high-energy rays may be used, but acid generators that generate sulfonic acid, imidic acid, or methide acid are preferred. Specific examples of suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, etc. Specific examples of the acid generator include those described in paragraphs

[0122] to

[0142] of JP-A-2008-111103, JP-A-2018-5224, and JP-A-2018-25789. When the resist material of the present invention contains other acid generators, its content is preferably 0 to 200 parts by mass, more preferably 0.1 to 100 parts by mass, per 100 parts by mass of the base polymer.

[0231] Specific examples of the surfactant include those described in paragraphs

[0165] to

[0166] of JP-A-2008-111103. By adding the surfactant, the coatability of the resist material can be further improved or controlled. When the resist material of the present invention contains a surfactant, its content is preferably 0.0001 to 10 parts by mass with respect to 100 parts by mass of the base polymer. The surfactant may be used alone or in combination of two or more.

[0232] When the resist material of the present invention is a positive type, by blending a dissolution inhibitor, the difference in dissolution rate between the exposed portion and the unexposed portion can be further increased, and the resolution can be further improved. Specific examples of the dissolution inhibitor include a compound having a molecular weight preferably of 100 to 1000, more preferably 150 to 800, and containing two or more phenolic hydroxy groups in the molecule, and the hydrogen atoms of the phenolic hydroxy groups are substituted as a whole by acid-labile groups at a ratio of 0 to 100 mol%, or a compound having a carboxy group in the molecule, and the hydrogen atoms of the carboxy group are substituted as a whole by acid-labile groups at an average ratio of 50 to 100 mol%. Specifically, bisphenol A, trisphenol, phenolphthalein, cresol novolak, naphthalene carboxylic acid, adamantane carboxylic acid, compounds in which the hydrogen atoms of the hydroxy groups and carboxy groups of cholic acid are substituted with acid-labile groups, etc. are included. For example, they are described in paragraphs

[0155] to

[0178] of JP-A-2008-122932.

[0233] When the resist material of the present invention is a positive type and contains the dissolution inhibitor, its content is preferably 0 to 50 parts by mass, more preferably 5 to 40 parts by mass with respect to 100 parts by mass of the base polymer. The dissolution inhibitor may be used alone or in combination of two or more.

[0234] On the one hand, when the resist material of the present invention is negative, a negative pattern can be obtained by adding a crosslinking agent to reduce the dissolution rate of the exposed area. Specific examples of the crosslinking agent include epoxy compounds, melamine compounds, guanamine compounds, glycoluril compounds, or urea compounds substituted with at least one group selected from a methylol group, an alkoxymethyl group, and an acyloxymethyl group, isocyanate compounds, azide compounds, compounds containing a double bond such as an alkenyloxy group, and the like. These may be used as additives, or may be introduced as pendant groups on the polymer side chain. Further, a compound containing a hydroxy group can also be used as a crosslinking agent.

[0235] Specific examples of the epoxy compound include tris(2,3-epoxypropyl) isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, triethylolethane triglycidyl ether, and the like.

[0236] Specific examples of the melamine compound include hexamethylol melamine, hexamethoxymethyl melamine, a compound or a mixture thereof in which 1 to 6 methylol groups of hexamethylol melamine are methoxymethylated, hexamethoxyethyl melamine, hexaacyloxymethyl melamine, a compound or a mixture thereof in which 1 to 6 methylol groups of hexamethylol melamine are acyloxymethylated, and the like.

[0237] Specific examples of the guanamine compound include tetramethylol guanamine, tetramethoxymethyl guanamine, a compound or a mixture thereof in which 1 to 4 methylol groups of tetramethylol guanamine are methoxymethylated, tetramethoxyethyl guanamine, tetraacyloxy guanamine, a compound or a mixture thereof in which 1 to 4 methylol groups of tetramethylol guanamine are acyloxymethylated, and the like.

[0238] Specific examples of the glycoluril compound include tetramethylol glycoluril, tetramethoxy glycoluril, tetramethoxymethyl glycoluril, a compound or a mixture thereof in which 1 to 4 of the methylol groups of tetramethylol glycoluril are methoxymethylated, a compound or a mixture thereof in which 1 to 4 of the methylol groups of tetramethylol glycoluril are acyloxymethylated, and the like. Specific examples of the urea compound include tetramethylol urea, tetramethoxymethyl urea, a compound or a mixture thereof in which 1 to 4 of the methylol groups of tetramethylol urea are methoxymethylated, tetramethoxyethyl urea, and the like.

[0239] Specific examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, and the like.

[0240] Specific examples of the azide compound include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, 4,4'-oxybisazide, and the like.

[0241] Specific examples of the compound containing an alkenyloxy group include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, trimethylolpropane trivinyl ether, and the like.

[0242] When the resist material of the present invention is a negative type and contains the crosslinking agent, its content is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, based on 100 parts by mass of the base polymer. The crosslinking agent may be used alone or in combination of two or more kinds.

[0243] The water repellency improver improves the water repellency of the resist film surface and can be used in immersion lithography without using a top coat. As the water repellency improver, a polymer containing an alkyl fluoride group, a polymer containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue having a specific structure, etc. are preferable, and those exemplified in JP-A-2007-297590, JP-A-2008-111103, etc. are preferable. The water repellency improver needs to be dissolved in an alkaline developer or an organic solvent developer. The water repellency improver having the above-described specific 1,1,1,3,3,3-hexafluoro-2-propanol residue has good solubility in the developer. As the water repellency improver, a polymer containing a repeating unit containing an amino group or an amine salt has a high effect of preventing the evaporation of the acid in PEB and preventing the opening failure of the hole pattern after development. When the resist material of the present invention contains the water repellency improver, its content is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, based on 100 parts by mass of the base polymer. The water repellency improver may be used alone or in combination of two or more kinds and may be used in combination.

[0244] Specific examples of the acetylene alcohols include those described in paragraphs

[0179] to

[0182] of JP-A-2008-122932. When the resist material of the present invention contains the acetylene alcohols, its content is preferably 0 to 5 parts by mass, based on 100 parts by mass of the base polymer. The acetylene alcohols may be used alone or in combination of two or more kinds.

[0245] [Pattern Forming Method] When the resist material of the present invention is used for various integrated circuit manufacturing, known lithography techniques can be applied. For example, as a pattern forming method, a method including a step of forming a resist film on a substrate using the above-described resist material, a step of exposing the resist film with high energy rays, and a step of developing the exposed resist film using a developer can be mentioned.

[0246] First, the resist material of the present invention is applied onto a substrate for integrated circuit manufacturing (such as Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflection film, etc.) or a substrate for mask circuit manufacturing (such as Cr, CrO, CrON, MoSi2, SiO2, etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc. so that the coating film thickness becomes 0.01 to 2 μm. This is prebaked on a hot plate, preferably at 60 to 150 °C for 10 seconds to 30 minutes, more preferably at 80 to 120 °C for 30 seconds to 20 minutes to form a resist film.

[0247] Next, the resist film is exposed using high energy rays. Specific examples of the high energy rays include ultraviolet rays, far ultraviolet rays, EB, EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, γ-rays, synchrotron radiation, etc. When using ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer laser light, γ-rays, synchrotron radiation, etc. as the high energy rays, the exposure amount is preferably 1 to 200 mJ / cm 2 degree, more preferably 10 to 100 mJ / cm 2 degree and irradiated so as to be. When using EB as the high energy rays, the exposure amount is preferably 0.1 to 300 μC / cm 2 degree, more preferably 0.5 to 200 μC / cm 2It is drawn directly to that extent or using a mask for forming a target pattern. Note that the resist material of the present invention is particularly suitable for fine patterning by KrF excimer laser light, ArF excimer laser light, EB, EUV, X-rays, soft X-rays, γ-rays, synchrotron radiation among high-energy rays, and is particularly suitable for fine patterning by EB or EUV.

[0248] After exposure, PEB may or may not be performed on a hot plate or in an oven, preferably at 30 to 150°C for 10 seconds to 30 minutes, more preferably at 50 to 120°C for 30 seconds to 20 minutes.

[0249] After exposure or after PEB, an alkaline aqueous solution developer such as 0.1 to 10% by mass, preferably 2 to 5% by mass of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc. is used, and the exposed resist film is developed by an ordinary method such as a dip method, a puddle method, or a spray method for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, whereby a target pattern is formed. In the case of a positive resist material, the irradiated portion is dissolved in the developer, and the unexposed portion is not dissolved, and a target positive pattern is formed on the substrate. In the case of a negative resist material, it is the opposite of the case of the positive resist material, and the irradiated portion is insolubilized in the developer, and the unexposed portion is dissolved.

[0250] Using a positive resist material containing a base polymer containing an acid-labile group, a negative pattern can also be obtained by organic solvent development. Specific examples of the developer used at this time include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents may be used alone or in combination of two or more.

[0251] At the end of development, rinsing is performed. As the rinse liquid, a solvent that is miscible with the developer and does not dissolve the resist film is preferred. As such a solvent, alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents having 6 to 12 carbon atoms are preferably used.

[0252] Specific examples of the alcohol having 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol and the like.

[0253] Specific examples of the ether compound having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, di-n-hexyl ether and the like.

[0254] Specific examples of the alkane having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane and the like. Specific examples of the alkene having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene and the like. Specific examples of the alkyne having 6 to 12 carbon atoms include hexyne, heptyne, octyne and the like.

[0255] Specific examples of the aromatic solvent include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, mesitylene, and the like.

[0256] Performing rinsing can reduce the occurrence of resist pattern collapse and defects. Also, rinsing is not necessarily essential, and the amount of solvent used can be reduced by not performing rinsing.

[0257] The developed hole pattern or trench pattern can also be shrunk by thermal flow, RELACS technology, or DSA technology. A shrinking agent is applied onto the hole pattern, and crosslinking of the shrinking agent occurs on the surface of the resist film due to the diffusion of the acid catalyst from the resist film during baking, and the shrinking agent adheres to the sidewalls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds, removing the excess shrinking agent and shrinking the hole pattern.

Examples

[0258] Hereinafter, synthesis examples, examples, and comparative examples are shown to specifically explain the present invention, but the present invention is not limited to the following examples.

[0259] The structures of the bis-onium salt PAG-PDQ-1 to PAG-PDQ-11, which is an acid generator and quencher used in the resist material, are shown below.

Chemical formula

[0260]

Chemical formula

[0261]

Chemical formula

[0262] [Chemical]

[0263] [Chemical]

[0264] [Synthesis Example] Synthesis of Base Polymers (Polymers P-1 to P-5) Combined with each monomer, a copolymerization reaction was carried out in THF as a solvent, put into methanol, the precipitated solid was washed with hexane, then isolated and dried to obtain base polymers (Polymers P-1 to P-5) with the following compositions. The compositions of the obtained base polymers were 1 Confirmed by 1H-NMR, Mw and Mw / Mn were confirmed by GPC (solvent: THF, standard: polystyrene). [Chemical]

[0265] [Examples 1 to 18, Comparative Examples 1 to 3] Preparation and Evaluation of Resist Materials (1) Preparation of Resist Materials A solution in which each component was dissolved with the composition shown in Table 1 was filtered through a 0.2 μm size filter to prepare a resist material.

[0266] In Table 1, each component is as follows. Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) EL (ethyl lactate) DAA (diacetone alcohol)

[0267] Comparative acid generator and quencher: cPAG-PDQ-1 [Chemical]

[0268] Comparative acid generator: cPAG-1 [Chemical]

[0269] Blend acid generator: bPAG-1, bPAG-2

Chem.

[0270] Blend quencher: bPDQ-1

Chem.

[0271] Comparative quencher: cPDQ-1

Chem.

[0272] (2) EUV Lithography Evaluation Each resist material shown in Table 1 was spin-coated on a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content: 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a film thickness of 20 nm, and prebaked at 105 °C for 60 seconds using a hot plate to produce a resist film with a film thickness of 40 nm. The resist film was exposed using an EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.7, dipole illumination) manufactured by ASML, PEB was performed at the temperature described in Table 1 on a hot plate for 60 seconds, and development was performed with a 2.38% by mass TMAH aqueous solution for 30 seconds to form a line and space with a pitch of 32 nm and a line width of 16 nm. Examples 1 to 17 and Comparative Examples 1 and 2 are positive resist materials, and Examples 18 and Comparative Example 3 are negative resist materials. Using a length measurement SEM (CG6300) manufactured by Hitachi High-Tech Corporation, the exposure dose at which a line pattern was formed with a dimension of 16 nm ± 1.6 nm was determined, and the LWR of the line pattern at this exposure dose was measured. The results are shown in Table 1.

[0273]

Table 1

[0274] From the results shown in Table 1, it was found that the resist material of the present invention containing a bis-onium salt including a divalent anion having a phenoxide anion structure substituted with an iodine atom and an arylsulfonate anion structure bonded to the aromatic ring of the phenoxide anion structure and an onium cation has high sensitivity and good LWR.

Claims

1. A resist material comprising a divalent anion having a phenoxide anion structure substituted with an iodine atom and an arylsulfonate anion structure bonded to the aromatic ring of the phenoxide anion structure, and an onium cation.

2. The resist material according to claim 1, wherein the bis-onium salt is represented by the following formula (1). 【化1】 (In the formula, m is an integer of 1 to 4. n is an integer of 0 to 3. However, 1 ≦ m + n ≦ 4. p is an integer of 0 to 10. X 1 and X 2 each independently represents a single bond, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond or a carbamate bond. R 1 is a hydrocarbyl group having 1 to 10 carbon atoms, a halogen atom other than an iodine atom, a nitro group or a cyano group, and the hydrocarbyl group may have at least one selected from halogen atoms, oxygen atoms, sulfur atoms and nitrogen atoms. R 2 is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms, and the hydrocarbylene group may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom. R 3 is a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a cyano group, a nitro group, a hydroxy group, a carboxy group, an amino group, a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms, -N(R 3A )-C(=O)-R 3B , -N(R 3A )-C(=O)-O-R 3B or -N(R 3A )-S(=O) 2 -R 3B , and the hydrocarbyl group, hydrocarbyloxy group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy group may contain at least one selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, an amino group, an ester bond, an ether bond, a urethane bond, a urea bond, a carbonate bond, an amide bond, a sulfonic acid bond, a carbonyl group, a sulfide group, and a sulfonyl group. R 3A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and the saturated hydrocarbyl group may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. R 3B is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms or an aryl group having 6 to 12 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. Ar is a (p + 2)-valent aromatic hydrocarbon group having 6 to 16 carbon atoms. M + is a sulfonium cation or an iodonium cation.)

3. The resist material according to claim 1, further comprising a base polymer.

4. The resist material according to claim 3, wherein the base polymer contains a repeating unit represented by the following formula (a1) or (a2). 【Chemistry 2】 (wherein R A is each independently a hydrogen atom or a methyl group.) Y 1 represents a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms which contains at least one selected from an ester bond, an ether bond, and a lactone ring, and the phenylene group, naphthylene group, and linking group may contain at least one selected from a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms, and a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms. Y 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 are each independently an acid labile group. R 13 is a saturated hydrocarbyl group having 1 to 4 carbon atoms, a halogen atom, a saturated hydrocarbylcarbonyl group having 2 to 5 carbon atoms, a cyano group or a saturated hydrocarbyloxycarbonyl group having 2 to 5 carbon atoms. R 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain an ether bond or an ester bond. a is an integer of 0 to 4.)

5. The resist material according to claim 4, which is a chemically amplified positive resist material.

6. The resist material according to claim 3, wherein the base polymer does not contain an acid-labile group.

7. The resist material according to claim 6, which is a chemically amplified negative resist material.

8. The resist material according to claim 1, further comprising an organic solvent.

9. The resist material according to claim 1, further comprising a quencher.

10. The resist material according to claim 1, further comprising an acid generator.

11. The resist material according to claim 1, further comprising a surfactant.

12. A pattern forming method comprising a step of forming a resist film on a substrate using the resist material according to any one of claims 1 to 11, a step of exposing the resist film with high-energy rays, and a step of developing the exposed resist film using a developer.

13. The pattern forming method according to claim 12, wherein the high-energy rays are ArF excimer laser light having a wavelength of 193 nm, KrF excimer laser light having a wavelength of 248 nm, an electron beam, or extreme ultraviolet light having a wavelength of 3 to 15 nm.

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