Resist material, resist composition, and pattern forming method

Abstract

To provide a resist material having higher sensitivity and higher resolution than conventional positive resist materials, small edge roughness and size variation, and excellent pattern profile after exposure; a resist composition containing the resist material; and a patterning process.SOLUTION: A resist material contains: a repeating unit (a) containing at least one iodine atom between a polymer main chain and a carboxylate; and a repeating unit (b), being a sulfonium salt or iodonium salt of a sulfonic acid bonded to a polymer main chain.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] With the increasing integration and speed of LSIs, the miniaturization of pattern rules is progressing rapidly. This is because the proliferation of 5G high-speed communication and artificial intelligence (AI) necessitates high-performance devices to process them. As a cutting-edge miniaturization technology, mass production of 5nm node devices is underway using extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm. Furthermore, research using EUV lithography is progressing for next-generation 3nm node and the following-generation 2nm node devices.

[0003] As miniaturization progresses, image blurring due to acid diffusion is becoming a problem. To ensure resolution in fine patterns with dimensions of 45 nm or larger, it has been suggested that controlling acid diffusion is important, in addition to improving dissolution contrast as has been conventionally proposed (Non-Patent Literature 1). However, since chemically amplified resist materials increase sensitivity and contrast through acid diffusion, attempting to suppress acid diffusion to the extreme by lowering the post-exposure bake (PEB) temperature or shortening the time results in a significant decrease in sensitivity and contrast.

[0004] The relationship between sensitivity, resolution, and edge roughness is shown as a triangle trade-off. To improve resolution, it is necessary to suppress acid diffusion, but as the acid diffusion distance decreases, sensitivity decreases.

[0005] Adding an acid generator that produces bulky acids is effective in suppressing acid diffusion. Therefore, it has been proposed to include repeating units derived from onium salts having polymerizable unsaturated bonds in the polymer. In this case, the polymer also functions as an acid generator (polymer-bound type acid generator). Patent Document 1 proposes sulfonium salts and iodonium salts having polymerizable unsaturated bonds that generate specific sulfonic acids. Patent Document 2 proposes sulfonium salts in which sulfonic acids are directly linked to the main chain.

[0006] To suppress acid diffusion, polymer-bound quencher resist materials have been proposed that use a sulfonium salt of a weak acid with a pKa of -0.8 or higher and polymerizable groups as the base polymer (Patent Documents 3-5). Patent Document 3 lists carboxylic acids, sulfonamides, phenols, and hexafluoroalcohols as examples of weak acids. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2006-045311 [Patent Document 2] Japanese Patent Publication No. 2006-178317 [Patent Document 3] International Publication No. 2019 / 167737 [Patent Document 4] International Publication No. 2022 / 264845 [Patent Document 5] Japanese Patent Publication No. 2022-115072 [Non-patent literature]

[0008] [Non-Patent Document 1] SPIE Vol.6520 65203L-1 (2007) [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention has been made in view of the above circumstances, and aims to provide a resist material that has higher sensitivity and resolution than conventional positive-type resist materials, has less edge roughness and dimensional variation, and has a good pattern shape after exposure, a resist composition using the resist material, and a pattern formation method. [Means for solving the problem]

[0010] To solve the above problems, the present invention provides a resist material comprising a repeating unit a containing at least one iodine atom between the polymer backbone and the carboxylate salt, and a repeating unit b which is a sulfonium salt or iodonium salt of a sulfonic acid bonded to the polymer backbone.

[0011] Such resist materials offer higher sensitivity and resolution than conventional positive-type resist materials, with reduced edge roughness and dimensional variation, and a better pattern shape after exposure.

[0012] Furthermore, in the present invention, it is preferable that the repeating unit a includes a repeating unit represented by the following general formula (a)-1 or (a)-2. [ka] (In the formula, R A X is a hydrogen atom or a methyl group. 1 X is a linking group having 1 to 12 carbon atoms, containing a single bond, a phenylene group, a naphthylene group, or an ester bond or ether bond. 2 These are single bonds, or linear, branched, or cyclic alkyl groups with 1 to 12 carbon atoms. Ren It is a group, and may contain one or more selected from ester groups, ether groups, amide groups, lactone rings, sultone rings, and halogen atoms. 3 R is a linear or branched alkylene group having 1 to 10 carbon atoms, which may have one or more selected from an ether group, an ester group, an aromatic group, a double bond, and a triple bond, and has 1 to 4 fluorine atoms.1 is independently a hydroxy group, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. m is an integer of 1 to 4, and n is an integer of 0 to 3. R 2 ~R 6 are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a hetero atom. Further, any two of R 2 、R 3 and R 4 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.)

[0013] As the repeating unit a, such a structure is preferable.

[0014] In the present invention, it is preferable that the repeating unit b contains at least one selected from the repeating units represented by the following general formulas (b1) to (b4).

Chemical formula

[0015] A structure like this is preferred for the repeating unit b.

[0016] At this time, the aforementioned Z 2B It is preferable that it contains at least one iodine atom.

[0017] Such a structure is more preferable for the repeating unit b.

[0018] Furthermore, in the present invention, it is preferable that the repeating unit c further contains a carboxyl group and / or a phenolic hydroxyl group, in which one or both hydrogen atoms are substituted with an acid-unstable group.

[0019] Such resist materials result in resist materials that are more sensitive and have less dimensional variation.

[0020] In this case, it is preferable that the repeating unit c is at least one selected from the repeating units represented by the following general formulas (c1) and (c2). [ka] (In the formula, R A Each of these is independently either a hydrogen atom or a methyl group. 1 This is a linking group having 1 to 12 carbon atoms, containing a single bond, a phenylene group, a naphthylene group, or an ester bond, an ether bond, or a lactone ring. 2 These are single bonds, ester bonds, or amide bonds. 11 and R 12R is an acid-unstable group. 13 R is a fluorine atom, a trifluoromethyl group, a cyano group, or an alkyl group having 1 to 6 carbon atoms. 14 (a is a single-bonded, linear, or branched alkanediyl group having 1 to 6 carbon atoms, some of which may be substituted with ether or ester bonds. a is 1 or 2. b is an integer from 0 to 4.)

[0021] A structure like this is preferred for the repeating unit c.

[0022] Furthermore, in the present invention, it is preferable that the resist material further contains repeating units d having adhesive groups selected from hydroxyl groups, carboxyl groups, lactone rings, carbonate groups, thiocarbonate groups, carbonyl groups, cyclic acetal groups, ether bonds, ester bonds, sulfonic acid ester bonds, cyano groups, amide groups, -OC(=O)-S-, and -OC(=O)-NH-.

[0023] Such a resist material will have excellent adhesion to the substrate.

[0024] Furthermore, in the present invention, it is preferable that the molecular weight of the resist material is in the range of 1,000 to 100,000.

[0025] Such a resist material will have excellent heat resistance, maintain alkali solubility, and will not exhibit the trailing phenomenon after pattern formation.

[0026] Furthermore, the present invention provides a resist composition that includes the resist material described above.

[0027] Such a resist composition offers higher sensitivity and resolution than conventional positive-type resist materials, with reduced edge roughness and dimensional variation, and a good pattern shape after exposure.

[0028] In this case, it is preferable that the mixture further contains one or more selected from an acid generator, an organic solvent, a quencher, and a surfactant.

[0029] Such substances can be added to the resist composition of the present invention.

[0030] Furthermore, the present invention provides a pattern formation method comprising the steps of: forming a resist film on a substrate using the resist composition described above; exposing the resist film with high-energy rays; and developing the exposed resist film using a developer.

[0031] This pattern formation method allows for the creation of patterns with good shape.

[0032] In this case, it is preferable to use i-rays, KrF excimer laser light, ArF excimer laser light, electron beams, or extreme ultraviolet light with a wavelength of 3 to 15 nm as the high-energy beam.

[0033] Such high-energy rays can be used in the pattern formation method of the present invention. [Effects of the Invention]

[0034] As described above, the present invention provides a resist material, a resist composition using the resist material, and a pattern formation method that offer higher sensitivity and resolution than conventional positive-type resist materials, with smaller edge roughness and dimensional variations, and a good pattern shape after exposure. [Modes for carrying out the invention]

[0035] As described above, there has been a need for the development of a resist material that offers higher sensitivity and resolution than conventional positive-type resist materials, has less edge roughness and dimensional variation, and exhibits a good pattern shape after exposure, as well as a resist composition using the said resist material and a pattern formation method.

[0036] The inventors of the present invention have diligently conducted research to obtain a positive-type resist that meets the recent demand for high resolution and low edge roughness (LWR) and dimensional variation (CDU). As a result, they have found that it is necessary to minimize the acid diffusion distance and to make the acid concentration within the resist film uniform in the exposed area. They have discovered that it is effective to use a polymer as a base polymer that has a sulfonium or iodonium salt of a carboxylic acid containing an iodine atom, and a sulfonium or iodonium salt of a sulfonic acid as repeating units.

[0037] Furthermore, in order to improve the dissolution contrast, we discovered that by introducing repeating units in which hydrogen atoms of carboxyl groups or phenolic hydroxyl groups are substituted with acid-unstable groups, we can obtain a resist material that exhibits high sensitivity, significantly high alkali dissolution rate contrast before and after exposure, high sensitivity, a strong effect in suppressing acid diffusion, high resolution, and good post-exposure pattern shape, edge roughness, and dimensional variation, making it particularly suitable as a fine pattern formation material for ultra-large-scale integrated circuits (ULSIs) or photomasks. Based on these findings, we completed the present invention.

[0038] In other words, the present invention is a resist material comprising repeating unit a, which contains at least one iodine atom between the polymer backbone and the carboxylate salt, and repeating unit b, which is a sulfonium salt or iodonium salt of a sulfonic acid bonded to the polymer backbone.

[0039] The present invention will be described in detail below, but the present invention is not limited to these descriptions.

[0040] [Resist material] The resist material of the present invention comprises repeating unit a, which contains at least one iodine atom between the polymer backbone and the carboxylate salt, and repeating unit b, which is a sulfonium salt or iodonium salt of a sulfonic acid bonded to the polymer backbone. Such repeating unit a preferably includes those represented by the following general formula (a)-1 or (a)-2. [ka] (In the formula, R A X is a hydrogen atom or a methyl group. 1 X is a linking group having 1 to 12 carbon atoms, containing a single bond, a phenylene group, a naphthylene group, or an ester bond or ether bond. 2 These are single bonds, or linear, branched, or cyclic alkyl groups with 1 to 12 carbon atoms. Ren It is a group, and may contain one or more selected from ester groups, ether groups, amide groups, lactone rings, sultone rings, and halogen atoms. 3 R is a linear or branched alkylene group having 1 to 10 carbon atoms, which may have one or more selected from an ether group, an ester group, an aromatic group, a double bond, and a triple bond, and has 1 to 4 fluorine atoms. 1 Each of these is independently a hydroxyl group, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. m is an integer from 1 to 4, and n is an integer from 0 to 3. R 2 ~R 6 Each of these is independently a monovalent hydrocarbon group having 1 to 25 carbon atoms, which may contain heteroatoms. 2 , R 3 and R 4 Any two of these may bond to each other, forming a ring with the sulfur atom to which they are bonded.

[0041] In the formula, R A X is a hydrogen atom or a methyl group, with a methyl group being preferred. 1 This is a linking group having 1 to 12 carbon atoms, containing a single bond, a phenylene group, a naphthylene group, or an ester bond or ether bond, and it is preferable that it contains a single bond or a phenylene group. 2 These are single bonds, or linear, branched, or cyclic alkyl groups with 1 to 12 carbon atoms. Ren The group may contain one or more selected from ester groups, ether groups, amide groups, lactone rings, sultone rings, and halogen atoms, and those containing ether groups are preferred. 3R is a linear or branched alkylene group having 1 to 10 carbon atoms, which may have one or more selected from an ether group, an ester group, an aromatic group, a double bond, and a triple bond, and may have 1 to 4 fluorine atoms, with a preference for having 2 fluorine atoms. 1 Each of these is independently a hydroxyl group, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine, with fluorine being preferred. m is an integer from 1 to 4, and n is an integer from 0 to 3, with m=1 to 2 and n=0 to 1 being preferred. 2 ~R 6 Each of these is independently a monovalent hydrocarbon group having 1 to 25 carbon atoms, which may contain heteroatoms, and aromatic hydrocarbon groups are preferred.

[0042] The repeating unit a is a quencher containing at least one iodine atom between the polymer main chain and the carboxylate salt, and is a quencher-bound polymer. Preferably, the repeating unit a has an iodized benzene ring skeleton and a sulfonium salt or iodonium salt structure of a carboxylic acid having a fluorine atom. Quencher-bound polymers have a high effect in suppressing acid diffusion and, as mentioned above, have excellent resolution. This makes it possible to achieve high resolution, low LWR, and low CDU.

[0043] The anionic portion of the monomer that gives repeating unit a1 represented by the above general formula (a)-1 and repeating unit a2 represented by the above general formula (a)-2 includes, but is not limited to, the following. Note that in the following formulas, R A This is the same as above.

[0044] [ka]

[0045] [ka]

[0046] [ka]

[0047] [ka]

[0048] [ka]

[0049] [ka]

[0050] [ka]

[0051] [ka]

[0052] [ka]

[0053] The cations of the sulfonium salt represented by the above general formula (a)-1 include, but are not limited to, those listed below. [ka]

[0054] [ka]

[0055] [ka]

[0056]

change

[0057]

change

[0058]

change

[0059]

change

[0060]

change

[0061]

change

[0062]

change

[0063]

change

[0064]

change

[0065]

change

[0066]

change

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070] [ka]

[0071] The cations of the iodonium salt represented by the above general formula (a)-2 include, but are not limited to, the following.

[0072] [ka]

[0073] The resist material further contains repeating units b derived from an onium salt containing polymerizable unsaturated bonds, i.e., repeating units b which are sulfonium or iodonium salts of sulfonic acid bonded to the polymer main chain. Preferred repeating units b include the repeating unit represented by the following general formula (b1) (hereinafter also referred to as repeating unit b1), the repeating unit represented by the following general formula (b2) (hereinafter also referred to as repeating unit b2), the repeating unit represented by the following general formula (b3) (hereinafter also referred to as repeating unit b3), and the repeating unit represented by the following general formula (b4) (hereinafter also referred to as repeating unit b4). It is preferable that the repeating unit b includes at least one selected from the repeating units represented by the following general formulas (b1) to (b4). The repeating units b1 to b4 can be used individually or in combination of two or more. [ka] (In the formula, R A Each of these is independently either a hydrogen atom or a methyl group. 2A These are single bonds or ester bonds. 2B This is a single bond or a divalent group having 1 to 12 carbon atoms, and may contain one or more selected from ester bonds, ether bonds, lactone rings, bromine atoms, and iodine atoms. 3 This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, and -OZ. 31 -, -C(=O)-OZ 31 -or -C(=O)-NH-Z 31 - and Z 31 This is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms, or a phenylene group, and may contain one or more selected from a carbonyl group, an ester bond, an ether bond, a halogen atom, and a hydroxyl group. Rf 1 ~Rf 4 Each of these is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom. 23 ~R 27 Each of these is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, which may contain heteroatoms. 23 , R 24 and R 25 Any two of these may bond together to form a ring with the sulfur atom to which they are bonded.

[0074] In general formulas (b1) to (b4), R A Each of these is independently a hydrogen atom or a methyl group, with a methyl group being preferred. 2A The bond is either a single bond or an ester bond, with an ester bond being preferred. 2B This is a single bond or a divalent group having 1 to 12 carbon atoms, and may contain an ester bond, an ether bond, a lactone ring, a bromine atom, or an iodine atom, with the presence of an iodine atom being preferred. 3This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, and -OZ. 31 -, -C(=O)-OZ 31 -or -C(=O)-NH-Z 31 - and Z 31 This is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms, or a phenylene group, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom, or a hydroxyl group, and is preferably a fluorine atom. Rf 1 ~Rf 4 Each of these is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom, and it is preferable to have two or more fluorine atoms.

[0075] In general formulas (b1) to (b2), Rf 1 ~Rf 4 Each of these is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom. In particular, Rf 3 and Rf 4 Preferably, at least one of them is a fluorine atom, Rf 3 and Rf 4 It is more preferable that both atoms are fluorine atoms.

[0076] In general formulas (b1) to (b4), R 23 ~R 27 Each of these is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, which may contain heteroatoms. 23 , R 24 and R 25Any two of these groups may bond to each other to form a ring with the sulfur atom to which they are bonded. The monovalent hydrocarbon group may be linear, branched, or cyclic, and specific examples include C1-C12 alkyl groups, C6-C12 aryl groups, C7-C20 aralkyl groups, etc. Furthermore, some or all of the hydrogen atoms of these groups may be substituted with C1-C10 alkyl groups, halogen atoms, trifluoromethyl groups, cyano groups, nitro groups, hydroxyl groups, mercapto groups, C1-C10 alkoxy groups, C2-C10 alkoxycarbonyl groups, or C2-C10 acyloxy groups, and some of the carbon atoms of these groups may be substituted with carbonyl groups, ether bonds, or ester bonds.

[0077] At this time, the aforementioned Z 2B It is preferable that it contains at least one iodine atom.

[0078] In general formulas (b1) and (b3), specific examples of sulfonium cations include those similar to those exemplified as cations of sulfonium salts represented by general formula (a)-1 mentioned above.

[0079] In general formulas (b2) and (b4), specific examples of iodonium cations include those similar to those exemplified as cations of iodonium salts shown in general formula (a)-2 above.

[0080] Examples of monomers that give repeating unit b1 are listed below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0081] [ka]

[0082] [ka]

[0083]

Chem.

[0084]

Chem.

[0085] Also, as the monomer that gives the repeating unit b2, those having the following anions are also preferable. In the following formula, R A is the same as described above.

Chem.

[0086]

Chem.

[0093] Examples of monomers that give repeating unit b3 are listed below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0094] [ka]

[0095] Examples of monomers that give repeating unit b4 are listed below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0096] [ka]

[0097] Repeating units b1 to b4 function as acid generators. By binding the acid generator to the polymer backbone, acid diffusion is reduced, preventing a decrease in resolution due to blurring caused by acid diffusion. Furthermore, the uniform dispersion of the acid generator improves the low-weight ratio (LWR). When using a resist material containing repeating units b1 to b4, the addition of the additive-type acid generator described later can be omitted.

[0098] The resist material of the present invention can have all functions in one polymer by copolymerizing either or both of repeating units a1 and a2 having a function of a quencher of a sulfonium salt or iodonium salt of a carboxylic acid having a substituted or unsubstituted iodinated benzene ring bonded via an ester bond from the polymer main chain, and any one or more of repeating units b1 to b4 having a function of an acid generator. In this case, the materials added other than the polymer may be only an organic solvent or a surfactant, and because of the simple material composition, there is an advantage of high productivity.

[0099] In the resist material of the present invention, the polymerization rate of the quencher unit having a double bond is about the same as the polymerization rate of the acid generator having a double bond. Therefore, since the quencher and the acid generator are uniformly present in the polymer, the edge roughness after development is improved. When iodine is contained in the anion portion of the acid generator, the edge roughness is further improved by the improvement of the contrast in acid generation due to the increase in the number of photons absorbed. The repeating unit having a sulfonium salt or iodonium salt of an iodinated carboxylic acid possessed by the resist material of the present invention exhibits an effect of improving the edge roughness due to the improvement of the contrast of quencher decomposition by the increase in the number of photons absorbed by the absorption of iodine.

[0100] In order to enhance the dissolution contrast, the resist material may further contain a repeating unit c in which at least one of the hydrogen atoms of a carboxy group and a phenolic hydroxy group, or both, are substituted with an acid-labile group. Further, it is preferable that the repeating unit c is at least one selected from the repeating units represented by the following general formulas (c1) and (c2). Hereinafter, the repeating unit in which the hydrogen atom of the carboxy group is substituted with an acid-labile group is referred to as repeating unit c1, and the repeating unit in which the hydrogen atom of the phenolic hydroxy group is substituted with an acid-labile group is referred to as repeating unit c2.

[0101]

Chemical formula

[0102] In the formula, R A is independently a hydrogen atom or a methyl group, and a methyl group is preferred. Y 1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms with an ester bond, an ether bond or a lactone ring, and a single bond or a phenylene group is preferred. Y 2 is a single bond, an ester bond, or an amide bond, and a single bond is preferred. R 11 and R 12 are acid labile groups. R 13 is a fluorine atom, a trifluoromethyl group, a cyano group, or an alkyl group having 1 to 6 carbon atoms, and a fluorine atom is preferred. R 14 is a single bond, or a linear or branched alkanediyl group having 1 to 6 carbon atoms, and a part of its carbon atoms may be substituted with an ether bond or an ester bond, and an ester bond is preferred. a is 1 or 2, and a is preferably 1. b is an integer from 0 to 4, and b is preferably 0 or 1.)

[0103] Examples of the monomer that gives the repeating unit c1 include, but are not limited to, the following. In the following formula, R A and R 11 are the same as described above.) [ka]

[0104] [ka]

[0105] Examples of monomers that give repeating units c2 are listed below, but are not limited to these. Note that in the following formula, R A and R 12 This is the same as described above. [ka]

[0106] R 11 or R 12 Various acid-unstable groups can be selected, but examples include those represented by the following general formulas (AL-1) to (AL-3). [ka]

[0107] In the general formula (AL-1), c is an integer between 0 and 6. L1 This is a tertiary hydrocarbyl group having 4 to 61 carbon atoms, preferably 4 to 15 carbon atoms; a trihydrocarbyl silyl group in which each hydrocarbyl group is a saturated hydrocarbyl group having 1 to 6 carbon atoms; a carbonyl group; a saturated hydrocarbyl group having 4 to 20 carbon atoms including an ether bond or an ester bond; or a group represented by the general formula (AL-3).

[0108] R L1The tertiary hydrocarbyl group represented by can be saturated or unsaturated, and can be branched or cyclic. Specific examples include tert-butyl group, tert-pentyl group, 1,1-diethylpropyl group, 1-ethylcyclopentyl group, 1-butylcyclopentyl group, 1-ethylcyclohexyl group, 1-butylcyclohexyl group, 1-ethyl-2-cyclopentenyl group, 1-ethyl-2-cyclohexenyl group, and 2-methyl-2-adamantyl group. Examples of the trihydrocarbyl silyl group include trimethylsilyl group, triethylsilyl group, and dimethyl-tert-butylsilyl group. The saturated hydrocarbyl group containing the carbonyl group, ether bond, or ester bond may be linear, branched, or cyclic, but cyclic is preferred. Specific examples include 3-oxocyclohexyl group, 4-methyl-2-oxooxan-4-yl group, 5-methyl-2-oxooxolan-5-yl group, 2-tetrahydropyranyl group, and 2-tetrahydrofuranyl group.

[0109] Examples of acid-unstable groups represented by the general formula (AL-1) include tert-butoxycarbonyl group, tert-butoxycarbonylmethyl group, tert-pentyloxycarbonyl group, tert-pentyloxycarbonylmethyl group, 1,1-diethylpropyloxycarbonyl group, 1,1-diethylpropyloxycarbonylmethyl group, 1-ethylcyclopentyloxycarbonyl group, 1-ethylcyclopentyloxycarbonylmethyl group, 1-ethyl-2-cyclopentenyloxycarbonyl group, 1-ethyl-2-cyclopentenyloxycarbonylmethyl group, 1-ethoxyethoxycarbonylmethyl group, 2-tetrahydropyranyloxycarbonylmethyl group, and 2-tetrahydrofuranyloxycarbonylmethyl group.

[0110] Furthermore, other acid-unstable groups represented by the general formula (AL-1) include the groups represented by the following general formulas (AL-1)-1 to (AL-1)-10. [ka] (In the equation, dashed lines represent connections.)

[0111] In General Formulas (AL-1)-1 to (AL-1)-10, c is the same as described above. R L8 is each independently a saturated hydrocarbyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. R L9 is a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. R L10 is a saturated hydrocarbyl group having 2 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic.

[0112] In General Formula (AL-2), R L2 and R L3 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 18, preferably 1 to 10 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, an n-octyl group, and the like.

[0113] In General Formula (AL-2), R L4 is a hydrocarbyl group having 1 to 18, preferably 1 to 10 carbon atoms, which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated and may be linear, branched, or cyclic. Examples of the hydrocarbyl group include saturated hydrocarbyl groups having 1 to 18 carbon atoms, and some of the hydrogen atoms thereof may be substituted with a hydroxy group, an alkoxy group, an oxo group, an amino group, an alkylamino group, or the like. Examples of such substituted saturated hydrocarbyl groups include those shown below.

Chemical Formula

[0114] R L2 and R L3 and, R L2 and R L4or R L3 and R L4 These atoms may bond with each other to form a ring together with the carbon atoms to which they are bonded, or together with a carbon atom and an oxygen atom, and in this case, R involved in ring formation L2 and R L3 , R L2 and R L4 , or R L3 and R L4 Each of these is an alkanediyl group having 1 to 18 carbon atoms, preferably 1 to 10. The number of carbon atoms in the ring obtained by bonding these is preferably 3 to 10, more preferably 4 to 10.

[0115] Among the acid-unstable groups represented by the general formula (AL-2), those that are linear or branched include, but are not limited to, those shown in the following formulas (AL-2)-1 to (AL-2)-69. In the following formulas, dashed lines represent bonds. [ka]

[0116] [ka]

[0117] [ka]

[0118] [ka]

[0119] Among the acid-unstable groups represented by the general formula (AL-2), cyclic groups include tetrahydrofuran-2-yl group, 2-methyltetrahydrofuran-2-yl group, tetrahydropyran-2-yl group, and 2-methyltetrahydropyran-2-yl group.

[0120] Furthermore, examples of acid-unstable groups include those represented by the following general formulas (AL-2a) or (AL-2b). The resist material may be intermolecularly or intramolecularly crosslinked by these acid-unstable groups. [ka] (In the equation, dashed lines represent connections.)

[0121] In the general formula (AL-2a) or (AL-2b), R L11 and R L12 Each of these is independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 8 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. Also, R L11 and R L12 These may bond with each other to form a ring with the carbon atoms to which they are bonded, in which case R L11 and R L12 These are, independently, alkanediyl groups having 1 to 8 carbon atoms. L13 Each of these is independently a saturated hydrocarbylene group having 1 to 10 carbon atoms. The saturated hydrocarbylene group may be linear, branched, or cyclic. Each of d and e is independently an integer from 0 to 10, preferably from 0 to 5, and f is an integer from 1 to 7, preferably from 1 to 3.

[0122] In the general formula (AL-2a) or (AL-2b), L A This is an aliphatic saturated hydrocarbon group having 1 to 50 carbon atoms with (f+1) valency, an alicyclic saturated hydrocarbon group having 3 to 50 carbon atoms with (f+1) valency, an aromatic hydrocarbon group having 6 to 50 carbon atoms with (f+1) valency, or a heterocyclic group having 3 to 50 carbon atoms with (f+1) valency. Furthermore, some of the carbon atoms of these groups may be substituted with heteroatom-containing groups, and some of the hydrogen atoms bonded to the carbon atoms of these groups may be substituted with hydroxyl groups, carboxyl groups, acyl groups, or fluorine atoms. A Preferred examples include saturated hydrocarbon groups such as saturated hydrocarbylene groups, trivalent saturated hydrocarbon groups, and tetravalent saturated hydrocarbon groups having 1 to 20 carbon atoms, and arylene groups having 6 to 30 carbon atoms. The saturated hydrocarbon groups may be linear, branched, or cyclic.B These are -C(=O)-O-, -NH-C(=O)-O-, or -NH-C(=O)-NH-.

[0123] Examples of crosslinked acetal groups represented by general formulas (AL-2a) or (AL-2b) include the groups represented by the following formulas (AL-2)-70 to (AL-2)-77. [ka] (In the equation, dashed lines represent connections.)

[0124] In general formula (AL-3), R L5 , R L6 and R L7 Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 20 carbon atoms, cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, cyclic unsaturated hydrocarbyl groups having 3 to 20 carbon atoms, and aryl groups having 6 to 10 carbon atoms. L5 and R L6 And, R L5 and R L7 or R L6 and R L7 These atoms may bond with each other to form an alicyclic ring with 3 to 20 carbon atoms.

[0125] Examples of groups represented by the general formula (AL-3) include tert-butyl group, 1,1-diethylpropyl group, 1-ethylnorbonyl group, 1-methylcyclopentyl group, 1-isopropylcyclopentyl group, 1-ethylcyclopentyl group, 1-methylcyclohexyl group, 2-(2-methyl)adamantyl group, 2-(2-ethyl)adamantyl group, and tert-pentyl group.

[0126] In addition, the groups represented by the general formula (AL-3) include those represented by the following general formulas (AL-3)-1 to (AL-3)-19. [ka] (In the equation, dashed lines represent connections.)

[0127] In the general formula (AL-3)-1~(AL-3)-19, R L14 Each of these is independently a saturated hydrocarbyl group having 1 to 8 carbon atoms or an aryl group having 6 to 20 carbon atoms. L15 and R L17 Each of these is independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 20 carbon atoms. L16 This is an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. Furthermore, a phenyl group is preferred as the aryl group. F g is a fluorine atom or a trifluoromethyl group. g is an integer from 1 to 5.

[0128] Furthermore, examples of acid-unstable groups include those represented by the following general formulas (AL-3)-20 or (AL-3)-21. The resist material may be intramolecularly or intermolecularly crosslinked by these acid-unstable groups. [ka] (In the equation, dashed lines represent connections.)

[0129] In general formulas (AL-3)-20 and (AL-3)-21, R L14 This is the same as above. R L18 h is a saturated hydrocarbylene group with 1 to 20 carbon atoms and a (h+1) valence, or an arylene group with 6 to 20 carbon atoms and a (h+1) valence, and may contain heteroatoms such as oxygen, sulfur, or nitrogen atoms. The saturated hydrocarbylene group may be linear, branched, or cyclic. h is an integer from 1 to 3.

[0130] Examples of monomers that give repeating units containing an acid-unstable group represented by the general formula (AL-3) include (meth)acrylic acid esters containing the exo-isomer structure represented by the following general formula (AL-3)-22. [ka]

[0131] In general formula (AL-3)-22, R A This is the same as above. R Lc1 This is a saturated hydrocarbyl group having 1 to 8 carbon atoms or an aryl group having 6 to 20 carbon atoms, which may be substituted. The saturated hydrocarbyl group may be linear, branched, or cyclic. Lc2 ~R Lc11 Each of these is independently a C1-C15 hydrocarbyl group which may contain a hydrogen atom or a heteroatom. Examples of the heteroatom include an oxygen atom. Examples of the hydrocarbyl group include a C1-C15 alkyl group and a C6-C15 aryl group. Lc2 and R Lc3 And, R Lc4 and R Lc6 And, R Lc4 and R Lc7 And, R Lc5 and R Lc7 And, R Lc5 and R Lc11 And, R Lc6 and R Lc10 And, R Lc8 and R Lc9 or R Lc9 and R Lc10 These may be bonded to each other and form a ring with the carbon atoms to which they are bonded, and in this case, the groups involved in the bonding may be hydrocarbylene groups that include heteroatoms having 1 to 15 carbon atoms. Lc2 and R Lc11 And, R Lc8 and R Lc11 or R Lc4 and R Lc6 This means that adjacent carbon atoms bond to each other without any intermediary, forming a double bond. Furthermore, this formula also represents enantiomers.

[0132] Here, examples of monomers that give repeating units represented by the general formula (AL-3)-22 include those described in Japanese Patent Publication No. 2000-327633. Specifically, these include, but are not limited to, the following. Note that in the following formula, R A This is the same as described above. [ka]

[0133] Examples of monomers that give repeating units containing an acid-unstable group represented by general formula (AL-3) include (meth)acrylic acid esters containing a franziyl group, a tetrahydrofranziyl group, or an oxanorbornanediyl group, as shown in the following general formula (AL-3)-23. [ka]

[0134] In general formula (AL-3)-23, R A This is the same as above. R Lc12 and R Lc13 These are, independently, hydrocarbyl groups having 1 to 10 carbon atoms. Lc12 and R Lc13 These atoms may bond with each other to form an alicyclic ring with the carbon atoms to which they are bonded. Lc14 This is a franziyl group, a tetrahydrofranziyl group, or an oxanorbornanediyl group. Lc15 This is a C1-C10 hydrocarbyl group which may contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be linear, branched, or cyclic. Specific examples include a saturated C1-C10 hydrocarbyl group.

[0135] The monomers that give the repeating unit represented by the general formula (AL-3)-23 include, but are not limited to, the following. Note that in the following formula, R A The same applies as above, where Ac is an acetyl group and Me is a methyl group. [ka]

[0136] [ka]

[0137] The resist material may further contain repeating units d having adhesive groups selected from hydroxyl groups, carboxyl groups, lactone rings, carbonate groups, thiocarbonate groups, carbonyl groups, cyclic acetal groups, ether bonds, ester bonds, sulfonic acid ester bonds, cyano groups, amide groups, -OC(=O)-S-, and -OC(=O)-NH-.

[0138] Examples of monomers that give repeating units d include, but are not limited to, those listed below. Note that in the following formula, R A This is the same as described above. [ka]

[0139] [ka]

[0140] [ka]

[0141] [ka]

[0142] [ka]

[0143] [ka]

[0144] [ka]

[0145] [ka]

[0146] The resist material may further contain repeating units e that do not contain amino groups but contain iodine atoms. Examples of monomers that give repeating units e are, but are not limited to, those listed below. In the following formula, R A This is the same as described above. [ka]

[0147] [ka]

[0148] The resist material may contain repeating units f other than those described above. Examples of repeating units f include those derived from styrene, vinylnaphthalene, indene, acenaphthylene, coumarin, coumarone, and the like.

[0149] In the resist material, the content ratios of the repeating units a1, a2, b1, b2, b3, b4, c1, c2, d, e, and f are preferably 0≦a1<1.0, 0≦a2<1.0, 0<a1 + a2<1.0, 0≦b1≦0.5, 0≦b2≦0.5, 0≦b3≦0.5, 0≦b4≦0.5, 0<b1 + b2 + b3 + b4≦0.9, 0<a1 + a2 + b1 + b2 + b3 + b4≦1, 0≦c1≦0.9, 0≦c2≦0.9, 0≦c1 + c2≦0.9, 0≦d≦0.5, 0≦e≦0.5, and 0≦f≦0.5; more preferably 0.001≦a1≦0.8, 0.001≦a2≦0.8, 0.001≦a1 + a2≦0.8, 0≦b1≦0.8, 0≦b2≦0.8, 0≦b3≦0.8, 0≦b4≦0.8, 0.1≦b1 + b2 + b3 + b4≦0.8, 0≦c1≦0.8, 0≦c2≦0.8, 0≦c1 + c2≦0.8, 0≦d≦0.4, 0≦e≦0.4, and 0≦f≦0.4; still more preferably 0.005≦a1≦0.7, 0.005≦a2≦0.7, 0.005≦a1 + a2≦0.7, 0≦b1≦0.7, 0≦b2≦0.7, 0≦b3≦0.7, 0≦b4≦0.7, 0≦b1 + b2 + b3 + b4≦0.7, 0≦c1≦0.7, 0≦c2≦0.7, 0≦c1 + c2≦0.7, 0≦d≦0.3, 0≦e≦0.3, and 0≦f≦0.3. However, a1 + a2 + b1 + b2 + b3 + b4 + c1 + c2 + d + e + f = 1.0.

[0150] To synthesize the resist material, for example, monomers providing the above-described repeating units may be heated with a radical polymerization initiator added thereto in an organic solvent to perform polymerization.

[0151] Organic solvents used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, dioxane, propylene glycol monomethyl ether, γ-butyrolactone, and mixed solvents thereof. Polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The polymerization temperature is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

[0152] When copolymerizing monomers containing hydroxyl groups, the hydroxyl groups may be substituted with acetal groups that are easily deprotected by acids such as ethoxyethoxy groups during polymerization, and then deprotected with a weak acid and water after polymerization. Alternatively, they may be substituted with acetyl groups, formyl groups, pivaloyl groups, etc., and then subjected to alkaline hydrolysis after polymerization.

[0153] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and the acetoxy group may be deprotected by alkaline hydrolysis after polymerization to obtain hydroxystyrene or hydroxyvinylnaphthalene.

[0154] Ammonia water, triethylamine, etc., can be used as the base during alkaline hydrolysis. 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.

[0155] The resist material has a polystyrene-based weight-average molecular weight (Mw) of 1,000 to 500,000, more preferably 1,000 to 100,000, and even more preferably 2,000 to 30,000, determined by gel permeation chromatography (GPC) using THF as a solvent. If the Mw is 1,000 or higher, the resist material will have excellent heat resistance, and if it is 500,000 or lower, alkali solubility will be maintained and the trailing phenomenon will not occur after pattern formation.

[0156] Furthermore, if the molecular weight distribution (Mw / Mn) of the resist material is broad, the presence of low-molecular-weight and high-molecular-weight polymers may cause foreign matter to be observed on the pattern or deterioration of the pattern shape after exposure. As the pattern rule becomes finer, the influence of Mw and Mw / Mn tends to increase. Therefore, in order to obtain a resist material suitable for fine pattern dimensions, it is preferable that the Mw / Mn of the resist material be narrowly dispersed, between 1.0 and 2.0, and particularly between 1.0 and 1.5.

[0157] The resist material may contain two or more polymers with different composition ratios, Mw, and Mw / Mn. Alternatively, a polymer containing repeating units a and b may be blended with a polymer that does not contain repeating units a or b.

[0158] [Resist composition] Furthermore, the present invention provides a resist composition comprising the resist material described above. Preferably, the resist composition of the present invention further comprises one or more selected from a photoacid generator, an organic solvent, a quencher, and a surfactant. The individual components included in the resist composition will be described below.

[0159] [Acid Generator] The resist composition of the present invention may further contain an acid generator that generates a strong acid (hereinafter also referred to as an additive-type acid generator). Here, a strong acid means a compound that has sufficient acidity to cause a deprotection reaction of acid-unstable groups in the resist material. Examples of the acid generator include compounds that generate acid in response to active light or radiation (photoacid generators). Any compound that generates acid upon irradiation with high-energy rays can be used as the photoacid generator, but those that generate sulfonic acid, imido acid, or methidoic acid are preferred. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, etc. Specific examples of photoacid generators are those described in paragraphs

[0122] to

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

[0160] Furthermore, sulfonium salts represented by the following general formula (1-1) and iodonium salts represented by the following general formula (1-2) can also be suitably used as photoacid generators. [ka]

[0161] In general formulas (1-1) and (1-2), R 101 ~R 105 Each of these is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, which may contain heteroatoms. 101 , R 102 and R 103 Any two of these may bond with each other to form a ring with the sulfur atom to which they are bonded. The monovalent hydrocarbon group may be linear, branched, or cyclic, and specific examples are the same as those mentioned above.

[0162] In general formulas (1-1) and (1-2), X - This is an anion selected from the following general formulas (1A) to (1D). [ka]

[0163] In general formula (1A), R fa R is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in the following general formula (1A'). 107 Examples of hydrocarbyl groups represented by the symbol are those similar to those described later.

[0164] The anion represented by general formula (1A) is preferably the one represented by the following general formula (1A'). [ka]

[0165] In general formula (1A'), R 106 R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 107 This is a hydrocarbyl group having 1 to 38 carbon atoms, which may contain heteroatoms. The heteroatoms are preferably oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms, etc., with oxygen atoms being more preferred. The hydrocarbyl group is particularly preferred to have 6 to 30 carbon atoms in order to obtain high resolution in fine pattern formation.

[0166] R 107The hydrocarbyl group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and eicosanyl groups; cyclic saturated hydrocarbyl groups such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecanyl, tetracyclododecanyl, tetracyclododecanylmethyl, and dicyclohexylmethyl groups; unsaturated hydrocarbyl groups such as allyl and 3-cyclohexenyl groups; aryl groups such as phenyl, 1-naphthyl, and 2-naphthyl groups; and aralkyl groups such as benzyl and diphenylmethyl groups.

[0167] Furthermore, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, they may contain hydroxyl groups, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate groups, lactone rings, sultone rings, carboxylic acid anhydrides, haloalkyl groups, etc. Examples of heteroatom-containing hydrocarbyl groups include tetrahydrofuryl group, methoxymethyl group, ethoxymethyl group, methylthiomethyl group, acetamidomethyl group, trifluoroethyl group, (2-methoxyethoxy)methyl group, acetoxymethyl group, 2-carboxy-1-cyclohexyl group, 2-oxopropyl group, 4-oxo-1-adamantyl group, and 3-oxocyclohexyl group.

[0168] For details on the synthesis of sulfonium salts containing the anion represented by general formula (1A'), please refer to Japanese Patent Publication No. 2007-145797, Japanese Patent Publication No. 2008-106045, Japanese Patent Publication No. 2009-007327, Japanese Patent Publication No. 2009-258695, etc. In addition, sulfonium salts described in Japanese Patent Publication No. 2010-215608, Japanese Patent Publication No. 2012-041320, Japanese Patent Publication No. 2012-106986, Japanese Patent Publication No. 2012-153644, etc., can also be suitably used.

[0169] Examples of anions represented by general formula (1A) include those similar to those exemplified as anions represented by formula (1A) in Japanese Patent Publication No. 2018-197853.

[0170] In general formula (1B), R fb1 and R fb2 Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may independently contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in general formula (1A'). 107 Examples similar to those given in the explanation can be cited. fb1 and R fb2 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 This refers to the groups that bond to each other (-CF2-SO2-N - It may form a ring with -SO2-CF2-), in which case R fb1 and R fb2 The group obtained by the bonding of these two elements is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0171] In general formula (1C), R fc1 , R fc2 and R fc3Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may independently contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in general formula (1A'). 107 Examples similar to those given in the explanation can be cited. fc1 , R fc2 and R fc3 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 This refers to the groups that bond to each other (-CF2-SO2-C - It may form a ring with -SO2-CF2-), in which case R fc1 and R fc2 The group obtained by the bonding of these two elements is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0172] In general formula (1D), R fd R is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in general formula (1A'). 107 Examples similar to those given in the explanation can be cited.

[0173] The synthesis of sulfonium salts containing the anion represented by general formula (1D) is detailed in Japanese Patent Publication No. 2010-215608 and Japanese Patent Publication No. 2014-133723.

[0174] Examples of anions represented by general formula (1D) include those similar to those exemplified as anions represented by formula (1D) in Japanese Patent Publication No. 2018-197853.

[0175] Furthermore, the photoacid generator containing the anion represented by general formula (1D) does not have fluorine at the α-position of the sulfo group, but has two trifluoromethyl groups at the β-position, which gives it sufficient acidity to cleave acid-unstable groups in the resist material. Therefore, it can be used as a photoacid generator.

[0176] Furthermore, as a photoacid generator, one represented by the following general formula (2) can also be suitably used. [ka]

[0177] In general formula (2), R 201 and R 202 Each of these is independently a hydrocarbyl group having 1 to 30 carbon atoms, which may contain heteroatoms. 203 This is a hydrocarbylene group having 1 to 30 carbon atoms, which may contain heteroatoms. Also, R 201 and R 202 or R 201 and R 203 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, the ring is defined as R in the explanation of general formula (1-1). 101 and R 102 Examples of rings that can be formed when these elements combine with the sulfur atom to which they are bonded are similar to those exemplified.

[0178] R 201 and R 202The hydrocarbyl group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0 2,6 Examples include cyclic saturated hydrocarbyl groups such as decanyl and adamantyl groups; aryl groups such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, tert-butylnaphthyl, and anthracenyl groups. Furthermore, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, the group may contain hydroxyl groups, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate groups, lactone rings, sultone rings, carboxylic acid anhydrides, haloalkyl groups, etc.

[0179] R 203The hydrocarbylene group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include alkane diyl groups such as methylene, ethylene, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, heptadecane-1,17-diyl; cyclopentanediyl, cyclo Examples include cyclic saturated hydrocarbylene groups such as hexanediyl group, norbornanediyl group, and adamantanediyl group; and 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, and tert-butylnaphthylene group. Furthermore, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in the presence of hydroxyl groups, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate groups, lactone rings, sultone rings, carboxylic acid anhydrides, haloalkyl groups, etc. Oxygen atoms are preferred as the heteroatom.

[0180] In general formula (2), L 1 This is a 1-20 carbon atom hydrocarbylene group which may contain single bonds, ether bonds, or heteroatoms. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R203 Examples of hydrocarbylene groups shown are similar to those exemplified.

[0181] In general formula (2), X A , X B , X C and X D Each of these is 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 these is a fluorine atom or a trifluoromethyl group.

[0182] In general formula (2), k is an integer between 0 and 3.

[0183] As the photoacid generator represented by general formula (2), the one represented by general formula (2') below is preferred. [ka]

[0184] In general formula (2'), L 1 The same as above. R HF R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in general formula (1A'). 107 Examples similar to those given in the explanation can be cited. x and y are independent integers between 0 and 5, and z is an integer between 0 and 4.

[0185] Examples of photoacid generators represented by general formula (2) include those similar to those exemplified as photoacid generators represented by formula (2) in Japanese Patent Publication No. 2017-026980.

[0186] Of the aforementioned photoacid generators, those containing anions represented by general formula (1A') or (1D) are particularly preferred because they exhibit low acid diffusion and excellent solubility in resist solvents. Furthermore, those represented by general formula (2') are particularly preferred because they exhibit extremely low acid diffusion.

[0187] Furthermore, as the photoacid generator, a sulfonium salt or iodonium salt having an anion containing an aromatic ring substituted with an iodine or bromine atom can also be used. Examples of such salts are those represented by the following general formulas (3-1) or (3-2). [ka]

[0188] In general formulas (3-1) and (3-2), p is an integer satisfying 1 ≤ p ≤ 3. q and r are integers satisfying 1 ≤ q ≤ 5, 0 ≤ r ≤ 3, and 1 ≤ q + r ≤ 5. q is preferably an integer satisfying 1 ≤ q ≤ 3, and more preferably 2 or 3. r is preferably an integer satisfying 0 ≤ r ≤ 2.

[0189] In general formulas (3-1) and (3-2), X BI These are iodine atoms or bromine atoms, and when q is 2 or greater, they may be the same or different from each other.

[0190] In general formulas (3-1) and (3-2), L 11 This is a saturated hydrocarbylene group having 1 to 6 carbon atoms, which may contain a single bond, an ether bond, an ester bond, or an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched, or cyclic.

[0191] In general formulas (3-1) and (3-2), L 12 When r is 1, it is a single bond or a divalent linking group having 1 to 20 carbon atoms; when r is 2 or 3, it is a trivalent or tetravalent linking group having 1 to 20 carbon atoms, and the linking group may contain an oxygen atom, a sulfur atom, or a nitrogen atom.

[0192] In general formulas (3-1) and (3-2), R 401 This may include a hydroxyl group, a carboxyl group, a fluorine atom, a chlorine atom, a bromine atom, or an amino group, or a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, an amino group, or an ether bond, and may contain a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 10 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, or a saturated hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms, or -NR 401A -C(=O)-R 401B Alternatively, -NR 401A -C(=O)-OR 401B That is. R 401A R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may also contain a halogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, a saturated hydrocarbyl carbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbyl carbonyloxy group having 2 to 6 carbon atoms. 401B This 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 hydroxyl 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. The aliphatic hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbyloxycarbonyl group, saturated hydrocarbylcarbonyl group, and saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic. When p and / or r is 2 or more, each R 401 They may be the same or different from one another.

[0193] Of these, R 401 Examples include hydroxyl groups and -NR 401A -C(=O)-R 401B , -NR 401A -C(=O)-OR 401B Fluorine atoms, chlorine atoms, bromine atoms, methyl groups, methoxy groups, etc. are preferred.

[0194] In general formulas (3-1) and (3-2), Rf 11 ~Rf 14 Each of these is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one of these is either a fluorine atom or a trifluoromethyl group. Also, Rf 11 and Rf 12 These may combine to form a carbonyl group. In particular, Rf 13 and Rf 14 It is preferable that both are fluorine atoms.

[0195] In general formulas (3-1) and (3-2), R 402 , R 403 , R 404 , R 405 and R 406 Each of these is a C1-C20 hydrocarbyl group which may independently contain a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. For example, in the explanation of general formulas (1-1) and (1-2), R 101 ~R 105 Examples of hydrocarbyl groups shown are similar to those exemplified. Furthermore, some or all of the hydrogen atoms of these groups may be substituted with hydroxyl groups, carboxyl groups, halogen atoms, cyano groups, nitro groups, mercapto groups, sultone groups, sulfone groups, or sulfonium salt-containing groups, and some of the carbon atoms of these groups may be substituted with ether bonds, ester bonds, carbonyl groups, amide bonds, carbonate groups, or sulfonic acid ester bonds. Also, R 402 and R 403 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, the ring is R as described in the explanation of general formula (1-1). 101 and R 102 Examples of rings that can be formed when these elements combine with the sulfur atom to which they are bonded are similar to those exemplified.

[0196] Examples of cations for sulfonium salts represented by general formula (3-1) are the same as those exemplified for sulfonium salts represented by general formula (1-1). Similarly, examples of cations for iodonium salts represented by general formula (3-2) are the same as those exemplified for iodonium salts represented by general formula (1-2).

[0197] The anions of onium salts represented by general formula (3-1) or (3-2) include, but are not limited to, the following. Note that in the following formulas, X BI This is the same as above. [ka]

[0198] [ka]

[0199] [ka]

[0200] [ka]

[0201] [ka]

[0202] [ka]

[0203] [ka]

[0204] [ka]

[0205]

change

[0206]

change

[0207]

change

[0208]

change

[0209]

change

[0210]

change

[0211]

change

[0212]

change

[0213]

change

[0214]

change

[0215] [ka]

[0216] [ka]

[0217] [ka]

[0218] [ka]

[0219] [ka]

[0220] In the resist composition of the present invention, the content of the additive-type acid generator is preferably 0.1 to 50 parts by mass, and more preferably 1 to 40 parts by mass, per 100 parts by mass of the resist material. By the resist material containing repeating units b1 to b4 and / or the additive-type acid generator, the resist composition of the present invention can function as a chemically amplified resist composition.

[0221] [Quencher] The resist composition of the present invention may contain a quencher (hereinafter referred to as "other quenchers"). Examples of the other quenchers include conventional basic compounds. Examples of conventional basic compounds include primary, secondary, and tertiary aliphatic amines, hybrid amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, carbamates, and the like. Particularly preferred are primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Application Publication No. 2008-111103, especially amine compounds having a hydroxyl group, ether bond, ester bond, lactone ring, cyano group, or sulfonic acid ester bond, or compounds having a carbamate group described in Japanese Patent No. 3790649. By adding such basic compounds, it is possible to further suppress the diffusion rate of acids in the resist film or correct its shape, for example.

[0222] Other quenchers include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids and carboxylic acids whose α-position is not fluorinated, as described in Japanese Patent Publication No. 2008-158339. Sulfonic acids, imido acids, or methidic acids with α-fluorinated positions are necessary to deprotect the acid-unstable groups of carboxylic acid esters, but salt exchange with onium salts whose α-position is not fluorinated releases sulfonic acids or carboxylic acids whose α-position is not fluorinated. Since sulfonic acids and carboxylic acids whose α-position is not fluorinated do not undergo deprotection reactions, they function as quenchers. Another quencher is the onium salt of a carboxylic acid with α-fluorinated positions, as described in Japanese Patent Publication No. 5904180. α-Fluorocarboxylic acids have lower acidity than sulfonic acids, resulting in higher quenching ability and the formation of patterns with good roughness and resolution.

[0223] Other quenchers include the polymer-type quencher described in Japanese Patent Publication No. 2008-239918. This improves the rectangularity of the resist after patterning by oriented on the resist surface after coating. Polymer-type quenchers also have the effect of preventing film thinning of the pattern and rounding of the pattern top when a protective film for immersion lithography is applied.

[0224] In the resist composition of the present invention, the content of other quenchers is preferably 0 to 10 parts by mass, and more preferably 0 to 7 parts by mass, per 100 parts by mass of the resist material. The other quenchers can be used individually or in combination of two or more types.

[0225] [Organic solvents] The resist composition of the present invention may contain an organic solvent. The organic solvent is not particularly limited as long as it can dissolve the components described above and the components described later. Examples of such organic solvents include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, as described in paragraphs

[0144] to

[0145] of Japanese Patent Application Publication No. 2008-111103, alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, and ethylene glycol monoethyl ether. Examples include ethers such as ethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as 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, and propylene glycol monotert-butyl ether acetate; lactones such as γ-butyrolactone; and mixed solvents thereof.

[0226] In the resist composition of the present invention, the content of the organic solvent is preferably 100 to 10,000 parts by mass, and more preferably 200 to 8,000 parts by mass, per 100 parts by mass of the resist material.

[0227] [Other ingredients] In addition to the aforementioned components, surfactants, dissolution inhibitors, etc., are appropriately combined and blended according to the purpose to form a resist composition. In the exposed area, the dissolution rate of the resist material in the developer is accelerated by a catalytic reaction, resulting in an extremely sensitive resist composition. In this case, the dissolution contrast and resolution of the resist film are high, there is sufficient exposure margin, it has excellent process adaptability, and the pattern shape after exposure is good. Moreover, acid diffusion is suppressed, resulting in small differences in dimensional density. For these reasons, it is highly practical and can be used as a resist material for ultra-large-scale integrated circuits (ULSIs).

[0228] Examples of the surfactants mentioned above include those described in paragraphs

[0165] to

[0166] of Japanese Patent Publication No. 2008-111103. By adding a surfactant, the coatability of the resist composition can be further improved or controlled. The surfactant can be used alone or in combination of two or more types. In the resist composition of the present invention, the content of the surfactant is preferably 0.0001 to 10 parts by mass per 100 parts by mass of the resist material.

[0229] By incorporating a dissolution inhibitor, the difference in dissolution rates between the exposed and unexposed areas can be further increased, thereby improving resolution.

[0230] Examples of the aforementioned dissolution inhibitors include compounds having a molecular weight of preferably 100 to 1,000, more preferably 150 to 800, and containing two or more phenolic hydroxyl groups in the molecule, in which the hydrogen atoms of the phenolic hydroxyl groups are substituted with acid-unstable groups in a proportion of 0 to 100 mol% overall, or compounds containing a carboxyl group in the molecule, in which the hydrogen atoms of the carboxyl group are substituted with acid-unstable groups in an average proportion of 50 to 100 mol overall. Specifically, examples include compounds in which the hydrogen atoms of the hydroxyl group or carboxyl group of bisphenol A, trisphenol, phenolphthalein, cresol novolac, naphthalenecarboxylic acid, adamantanecarboxylic acid, and cholic acid are substituted with acid-unstable groups, as described in paragraphs

[0155] to

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

[0231] The content of the dissolution inhibitor is preferably 0 to 50 parts by mass, and more preferably 5 to 40 parts by mass, per 100 parts by mass of the resist material. The dissolution inhibitor can be used alone or in combination of two or more types.

[0232] The resist composition of the present invention may contain a water-repellent agent to improve the water repellency of the resist surface after spin coating. The water-repellent agent can be used in immersion lithography without a topcoat. Preferred water-repellent agents include polymer compounds containing alkyl fluoride, polymer compounds containing 1,1,1,3,3,3-hexafluoro-2-propanol residues of a specific structure, and those exemplified in Japanese Patent Publication No. 2007-297590 and Japanese Patent Publication No. 2008-111103 are more preferred. The water-repellent agent needs to be dissolved in an organic solvent developer. The water-repellent agent having the specific 1,1,1,3,3,3-hexafluoro-2-propanol residues mentioned above has good solubility in the developer. As a water-repellent agent, polymer compounds containing repeating units including amino groups or amine salts are highly effective in preventing acid evaporation during post-exposure baking (PEB) and preventing poor hole pattern opening after development. The water-repellency improving agent can be used alone or in combination of two or more types. In the resist composition of the present invention, the content of the water-repellency improving agent is preferably 0 to 20 parts by mass, and more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the resist material.

[0233] The resist composition of the present invention may also contain acetylene alcohols. Examples of acetylene alcohols include those described in paragraphs

[0179] to

[0182] of Japanese Patent Application Publication No. 2008-122932. In the resist composition of the present invention, the content of acetylene alcohols is preferably 0 to 5 parts by mass per 100 parts by mass of the resist material.

[0234] [Pattern formation method] When the resist composition of the present invention is used in the manufacture of various integrated circuits, known lithography techniques can be applied. Specifically, the present invention provides a pattern formation method comprising the steps of: forming a resist film on a substrate using the resist composition described above; exposing the resist film with high-energy rays; and developing the exposed resist film using a developer.

[0235] For example, the resist composition of the present invention is applied to a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective coating, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor coating, so that the coating thickness is 0.01 to 2 μm. This is then pre-baked 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.

[0236] Next, the resist film is exposed using high-energy rays. Examples of high-energy rays include ultraviolet rays, far ultraviolet rays, EB (electron beams), EUV (extreme ultraviolet rays), X-rays, soft X-rays, excimer lasers, i-rays, gamma rays, and synchrotron radiation. Among these, it is preferable to use i-rays, KrF excimer laser light, ArF excimer laser light, electron beams, or extreme ultraviolet rays with a wavelength of 3 to 15 nm. When using ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer lasers, gamma rays, synchrotron radiation, etc. as the high-energy rays, an exposure amount of preferably 1 to 200 mJ / cm is used, with a mask for forming the desired pattern. 2 To the extent, more preferably 10 to 100 mJ / cm² 2 Irradiate to the extent of [a certain degree]. When using EB as the high-energy beam, the exposure dose is preferably 0.1 to 100 μC / cm². 2 To a degree, more preferably 0.5 to 50 μC / cm² 2 The pattern is drawn either directly or using a mask to form the desired pattern. The resist composition of the present invention is particularly suitable for fine patterning using high-energy rays, including KrF excimer lasers, ArF excimer lasers, EB, EUV, X-rays, soft X-rays, gamma rays, and synchrotron radiation, and is especially suitable for fine patterning using EB or EUV.

[0237] After exposure, PEB may be performed on a hot plate at a temperature of preferably 50-150°C for 10 seconds to 30 minutes, more preferably at 60-120°C for 30 seconds to 20 minutes.

[0238] After exposure or PEB, the substrate is developed using a developer solution containing 0.1 to 10% by mass, preferably 2 to 5% by mass, of an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), or tetrabutylammonium hydroxide (TBAH), for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by conventional methods such as the dip method, puddle method, or spray method. The areas exposed to light dissolve in the developer solution, while the areas not exposed do not dissolve, forming the desired positive-type pattern on the substrate.

[0239] Negative development can also be performed to obtain a negative pattern by organic solvent development using a resist composition containing a resist material containing an acid-unstable group. The developers used in this process 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 crotate, ethyl crotate, Examples include 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 phenyl acetate, and 2-phenylethyl acetate. These organic solvents can be used individually or in combination of two or more.

[0240] Rinsing can be performed at the end of the development process. A solvent that mixes with the developer but does not dissolve the resist film is preferred as the rinsing solution. Preferred solvents include C3-C10 alcohols, C8-C12 ether compounds, C6-C12 alkanes, alkenes, alkynes, and aromatic solvents.

[0241] Specifically, alcohols with 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, and 3-hexanol. Examples include 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.

[0242] Examples of ether compounds 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, and di-n-hexyl ether.

[0243] Examples of alkanes with 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, and cyclononane. Examples of alkenes with 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Examples of alkynes with 6 to 12 carbon atoms include hexine, heptine, and octine.

[0244] Examples of aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0245] Rinsing can reduce the occurrence of resist pattern deformation and defects. However, rinsing is not always necessary, and omitting it can reduce the amount of solvent used.

[0246] The developed hole patterns and trench patterns can also be shrunk using thermal flow, RELACS, or DSA techniques. A shrinking agent is applied to the hole pattern, and crosslinking of the shrinking agent occurs on the surface of the resist due to the diffusion of an acid catalyst from the resist layer during baking, causing the shrinking agent to adhere to the sidewalls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the time is preferably 10 to 300 seconds, during which excess shrinking agent is removed and the hole pattern is reduced in size. [Examples]

[0247] The present invention will be specifically described below with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples.

[0248] [1] Synthesis of monomers [Synthesis Example 1] By ion exchange between sulfonium chloride salts and iodine-containing carboxylic acid compounds or carboxylic acid compounds having polymerizable double bonds, the following monomers 1 to 8 and comparative monomer 1 were obtained.

[0249] [ka]

[0250] [2] Polymer synthesis The acid-unstable group monomers (ALG monomers 1-4) and PAG monomers 1-6 used in the synthesis of the polymer are as follows. The polymer's Mw is a polystyrene-converted measurement obtained by GPC using THF as the solvent. [ka]

[0251] [ka]

[0252] [Synthesis Example 2-1] Synthesis of Polymer 1 In a 2 L flask, 3.0 g of monomer 1, 7.5 g of ALG monomer 4, 3.7 g of 3-hydroxystyrene, 6.9 g of PAG monomer 2, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and the reaction was allowed to proceed for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer 1. The composition of polymer 1 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0253] [Synthesis Example 2-2] Synthesis of Polymer 2 In a 2 L flask, 3.4 g of monomer 2, 9.1 g of ALG monomer 1, 3.7 g of 3-hydroxystyrene, 8.0 g of PAG monomer 3, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and the reaction was allowed to proceed for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer 2. The composition of polymer 2 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0254] [Synthesis Example 2-3] Synthesis of Polymer 3 In a 2 L flask, 3.6 g of monomer 3, 7.5 g of ALG monomer 3, 4.1 g of 3-hydroxy-4-methylstyrene, 9.2 g of PAG monomer 6, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and the reaction was allowed to proceed for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer 3. The composition of polymer 3 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0255] [Synthesis Example 2-4] Synthesis of Polymer 4 In a 2 L flask, 4.8 g of monomer 4, 6.8 g of ALG monomer 2, 3.6 g of 3-hydroxystyrene, 6.8 g of PAG monomer 1, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and the reaction was allowed to proceed for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer 4. The composition of polymer 4 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0256] [Synthesis Example 2-5] Synthesis of Polymer 5 In a 2 L flask, 5.5 g of monomer 5, 6.8 g of ALG monomer 2, 4.1 g of 3-hydroxystyrene, 8.3 g of PAG monomer 4, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and the reaction was allowed to proceed for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer 5. The composition of polymer 5 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0257] [Synthesis Example 2-6] Synthesis of Polymer 6 In a 2 L flask, 5.2 g of monomer 6, 6.8 g of ALG monomer 2, 4.1 g of 3-methyl-4-hydroxystyrene, 9.4 g of PAG monomer 5, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and the reaction was allowed to proceed for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer 6. The composition of polymer 6 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0258] [Synthesis Example 2-7] Synthesis of Polymer 7 In a 2 L flask, 4.6 g of monomer 7, 9.1 g of ALG monomer 1, 3.7 g of 3-hydroxystyrene, 8.0 g of PAG monomer 3, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and the reaction was allowed to proceed for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer 7. The composition of polymer 7 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0259] [Synthesis Example 2-8] Synthesis of Polymer 8 In a 2 L flask, 3.7 g of monomer 8, 6.9 g of ALG monomer 2, 3.7 g of 4-hydroxystyrene, 9.1 g of PAG monomer 4, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After raising the temperature to room temperature, 1.2 g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and the reaction was allowed to proceed for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer 8. The composition of polymer 8 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0260] [Comparative Synthesis Example 1] Synthesis of Comparative Polymer 1 monomer 4 Comparative polymer 1 was obtained using the same method as in synthesis example 2-4, except that it was not used. The composition of comparative polymer 1 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0261] [Comparative Synthesis Example 2] Synthesis of Comparative Polymer 2 monomer 4 Comparative polymer 2 was obtained in the same manner as in synthesis example 2-4, except that comparative monomer 1 was used instead. The composition of comparative polymer 2 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0262] [Comparative Synthesis Example 3] Synthesis of Comparative Polymer 3 monomer4 PAG monomer 1 Comparative polymer 3 was obtained in the same manner as in synthesis example 2-4, except that it was not used. The composition of comparative polymer 3 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0263] [Examples 1-19, Comparative Examples 1-3] A resist composition was prepared by dissolving each component in an organic solvent containing 50 ppm of Polyfox636, a surfactant manufactured by Omnova, as a surfactant, according to the compositions shown in Tables 1 and 2. The solution was then filtered through a 0.2 μm filter.

[0264] In Tables 1 and 2, the components are as follows: • Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (Diacetone Alcohol) EL (Ethyl Lactate) • Acid generator: PAG-1 (see structural formula below) • Quencher: Q-1~6 (See structural formula below) [ka]

[0265] [EUV exposure evaluation] Each resist composition shown in Tables 1 and 2 was spin-coated onto a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) had been formed to a thickness of 20 nm. The resist film was then pre-baked at 105°C for 60 seconds using a hot plate to produce a resist film with a thickness of 50 nm. An ASML EUV scanner NXE340 was then used to scan the resist film. 0(Exposure was performed using a hole pattern mask (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, wafer dimensions of 46 nm pitch, +20% bias), PEB was performed on a hot plate at the temperatures listed in Tables 1 and 2 for 60 seconds, and development was performed with a 2.38 mass% TMAH aqueous solution for 30 seconds to obtain a hole pattern with dimensions of 23 nm. The exposure amount when each hole was formed with a dimension of 23 nm was measured and defined as the sensitivity. Additionally, the dimensions of 50 holes were measured using a Hitachi CG6300 length measuring SEM, and the CDU (dimensional variation of 3σ) was determined. The results are shown in Tables 1 and 2.

[0266] [Table 1]

[0267] [Table 2]

[0268] The results in Tables 1 and 2 show that the resist composition containing the resist material of the present invention, which uses a polymer containing a repeating unit a having a sulfonium salt or iodonium salt structure of a carboxylic acid containing an iodine atom, and a repeating unit b having a sulfonium salt or iodonium salt of a sulfonic acid, satisfies sufficient sensitivity and dimensional uniformity (Examples 1-19). In contrast, Comparative Examples 1-3, which used resist compositions without the resist material of the present invention, showed inferior sensitivity and dimensional uniformity.

[0269] This specification includes the following embodiments: [1]: A resist material characterized by comprising repeating unit a which contains at least one iodine atom between the polymer backbone and the carboxylate salt, and repeating unit b which is a sulfonium salt or iodonium salt of a sulfonic acid bonded to the polymer backbone. [2]: The resist material according to [1], characterized in that the repeating unit a includes a repeating unit represented by the following general formula (a)-1 or (a)-2. [ka] (In the formula, R A X is a hydrogen atom or a methyl group. 1 X is a linking group having 1 to 12 carbon atoms, containing a single bond, a phenylene group, a naphthylene group, or an ester bond or ether bond. 2 These are single bonds, or linear, branched, or cyclic alkyl groups with 1 to 12 carbon atoms. Ren It is a group, and may contain one or more selected from ester groups, ether groups, amide groups, lactone rings, sultone rings, and halogen atoms. 3 R is a linear or branched alkylene group having 1 to 10 carbon atoms, which may have one or more selected from an ether group, an ester group, an aromatic group, a double bond, and a triple bond, and has 1 to 4 fluorine atoms. 1 Each of these is independently a hydroxyl group, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. m is an integer from 1 to 4, and n is an integer from 0 to 3. R 2 ~R 6 Each of these is independently a monovalent hydrocarbon group having 1 to 25 carbon atoms, which may contain heteroatoms. 2 , R 3 and R 4 Any two of these may bond to each other, forming a ring with the sulfur atom to which they are bonded. [3]: The resist material according to [1] or [2] above, characterized in that the repeating unit b includes at least one selected from the repeating units represented by the following general formulas (b1) to (b4). [ka] (In the formula, R A Each of these is independently either a hydrogen atom or a methyl group. 2A These are single bonds or ester bonds. 2BThis is a single bond or a divalent group having 1 to 12 carbon atoms, and may contain one or more selected from ester bonds, ether bonds, lactone rings, bromine atoms, and iodine atoms. 3 This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, and -OZ. 31 -, -C(=O)-OZ 31 -or -C(=O)-NH-Z 31 - and Z 31 This is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms, or a phenylene group, and may contain one or more selected from a carbonyl group, an ester bond, an ether bond, a halogen atom, and a hydroxyl group. Rf 1 ~Rf 4 Each of these is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom. 23 ~R 27 Each of these is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, which may contain heteroatoms. 23 , R 24 and R 25 Any two of these may bond together to form a ring with the sulfur atom to which they are bonded. [4]:Z above 2B The resist material according to [3] above, characterized in that it contains at least one iodine atom. [5]: The resist material according to any one of the above [1] to [4], further comprising a repeating unit c in which either or both hydrogen atoms of a carboxyl group and / or a phenolic hydroxyl group are substituted with an acid-unstable group. [6]: The resist material according to [5], characterized in that the repeating unit c is at least one selected from the repeating units represented by the following general formulas (c1) and (c2). [ka] (In the formula, R A Each of these is independently either a hydrogen atom or a methyl group. 1This is a linking group having 1 to 12 carbon atoms, containing a single bond, a phenylene group, a naphthylene group, or an ester bond, an ether bond, or a lactone ring. 2 These are single bonds, ester bonds, or amide bonds. 11 and R 12 R is an acid-unstable group. 13 R is a fluorine atom, a trifluoromethyl group, a cyano group, or an alkyl group having 1 to 6 carbon atoms. 14 (a is a single-bonded, linear, or branched alkanediyl group having 1 to 6 carbon atoms, some of which may be substituted with ether or ester bonds. a is 1 or 2. b is an integer from 0 to 4.) [7]: The resist material of any one of the above [1] to [6], characterized in that the resist material further comprises a repeating unit d having an adhesive group selected from a hydroxyl group, a carboxyl group, a lactone ring, a carbonate group, a thiocarbonate group, a carbonyl group, a cyclic acetal group, an ether bond, an ester bond, a sulfonic acid ester bond, a cyano group, an amide group, -OC(=O)-S-, and -OC(=O)-NH-. [8]: A resist material according to any one of the above [1] to [7], characterized in that the molecular weight of the resist material is in the range of 1,000 to 100,000. [9]: A resist composition characterized by comprising any one of the resist materials described in [1] to [8] above.

[10] : The resist composition according to [9], further comprising one or more selected from an acid generator, an organic solvent, a quencher, and a surfactant.

[11] : A pattern forming method comprising the steps of forming a resist film on a substrate using the resist composition of [9] or

[10] above, exposing the resist film with high-energy rays, and developing the exposed resist film using a developer.

[12] : The pattern formation method of

[11] , characterized in that the high-energy beam is an i-ray, KrF excimer laser light, ArF excimer laser light, an electron beam, or extreme ultraviolet light with a wavelength of 3 to 15 nm.

[0270] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention.

Claims

1. A resist material comprising a polymer containing repeating units a, which include at least one iodine atom between the polymer main chain and a carboxylate salt, and repeating units b, which are sulfonium salts or iodonium salts of sulfonic acid bonded to the polymer main chain, wherein the repeating units a include repeating units represented by the following general formula (a)-1 or (a)-2. 【Chemistry 1】 (wherein, R Ａ is a hydrogen atom or a methyl group. X １ is a single bond. X ２ is -(CH₂)₂O-. X ３ is -C(=O)O-CH₂-CF₂- or -C(=O)O-CH(isopropyl group)-CF₂-. R １ are each independently a hydroxy group, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. m is an integer of 1 to 4, and n is an integer of 0 to 3. R ２ to R ６ are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a hetero atom. Also, any two of R ２ , R ３ and R ４ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.)

2. The resist material according to claim 1, characterized in that the repeating unit b includes at least one selected from the repeating units represented by the following general formulas (b1) to (b2). 【Chemistry 2】 (In the formula, R Ａ Each of these is independently either a hydrogen atom or a methyl group. ２Ａ This is an ester bond. Z ２Ｂ These are -(adamantane)-C(=O)O-, -(CH2)2O-(C6H3I)-C(=O)O-, -(CH2)2O-(C6H2I2)-C(=O)O-, or -(CH2)2O-(C6HI3)-C(=O)O-. Rf １ ~Rf ４ Each of these is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom. ２３ ~R ２７ Each of these is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, which may contain heteroatoms. Also, R ２３ , R ２４ and R ２５ Any two of these may bond to each other, forming a ring with the sulfur atom to which they are bonded.

3. Said Z ２Ｂ The resist material according to claim 2, characterized in that it is -(CH2)2O-(C6H3I)-C(=O)O-, -(CH2)2O-(C6H2I2)-C(=O)O-, or -(CH2)2O-(C6HI3)-C(=O)O-.

4. The resist material according to claim 1, characterized in that the polymer further comprises a repeating unit c in which either a carboxyl group or a phenolic hydroxyl group, or both a carboxyl group and a phenolic hydroxyl group, has hydrogen atoms substituted with an acid-unstable group.

5. The resist material according to claim 4, characterized in that the repeating unit c is at least one selected from the repeating units represented by the following general formulas (c1) and (c2). 【Transformation 3】 (In the formula, R Ａ Each of these is independently either a hydrogen atom or a methyl group. １ This is a linking group having 1 to 12 carbon atoms, containing a single bond, a phenylene group, a naphthylene group, or an ester bond, an ether bond, or a lactone ring. ２ These are single bonds, ester bonds, or amide bonds. １１ and R １２ R is an acid-unstable group. １３ R is a fluorine atom, a trifluoromethyl group, a cyano group, or an alkyl group having 1 to 6 carbon atoms. １４ (a is a single-bonded, linear, or branched alkanediyl group having 1 to 6 carbon atoms, and some of the carbon atoms of the alkanediyl group may be substituted with ether bonds or ester bonds. a is 1 or 2. b is an integer from 0 to 4.)

6. The resist material according to claim 1, characterized in that the molecular weight of the resist material is in the range of 1,000 to 100,000.

7. A resist composition characterized by comprising a resist material according to any one of claims 1 to 6.

8. The resist composition according to claim 7, further characterized by containing one or more selected from an acid generator, an organic solvent, a quencher, and a surfactant.

9. A pattern formation method comprising the steps of: forming a resist film on a substrate using the resist composition described in claim 7; exposing the resist film with high-energy rays; and developing the exposed resist film using a developer.

10. The pattern formation method according to claim 9, characterized in that the high-energy beam used is an i-ray, KrF excimer laser light, ArF excimer laser light, an electron beam, or extreme ultraviolet light with a wavelength of 3 to 15 nm.

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