Positive-type resist material and pattern formation method

Abstract

To provide a positive resist material that exhibits sensitivity and resolution that surpass those of the conventional positive resist material, is small in edge roughness and dimensional variation, and is good in pattern shape after exposure, and a pattern forming process.SOLUTION: A positive resist material comprises a base polymer comprising a repeat unit represented by the formula (a) [where R represents a specific group, including a phenyl group and an unsaturated aliphatic hydrocarbyl group].SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a positive-type resist material 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 triangle trade-off relationship between sensitivity, resolution, and edge roughness (LER, LWR) is shown. 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.

[0007] The structure of the acid-unstable group of the base polymer is important as a component that contributes to the performance of positive-type resist materials. Here, a tertiary ester-type acid-unstable group bonded to an aromatic group substituted with a fluorine atom has been proposed (Patent Documents 3 and 4). The tertiary ester-type acid-unstable group bonded to the aromatic group has a very high elimination reactivity to acid, making it difficult to control acid diffusion, but by introducing a fluorine atom to the aromatic group, the elimination reactivity is moderately suppressed.

[0008] On the other hand, the tertiary ester-type acid-unstable group having an olefin, as exemplified in paragraph

[0036] of Patent Document 5, has very high acid-induced elimination reactivity, making it difficult to control acid diffusion. Furthermore, the secondary ester-type acid-unstable group having an olefin, as exemplified in paragraph

[0188] of Patent Document 6, has low acid-induced elimination reactivity, which presents the problem of not being able to obtain a high dissolution contrast. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2006-045311 [Patent Document 2] Japanese Patent Publication No. 2006-178317 [Patent Document 3] Patent No. 3832564 [Patent Document 4] Patent No. 5655754 [Patent Document 5] Japanese Patent Publication No. 2001-302728 [Patent Document 6] Japanese Patent Publication No. 2022-025610 [Non-patent literature]

[0010] [Non-Patent Document 1] SPIE Vol. 6520 65203L-1 (2007) [Overview of the project] [Problems that the invention aims to solve]

[0011] The present invention has been made in view of the above circumstances, and aims to provide a positive-type resist material and a pattern forming method that have higher sensitivity and resolution than conventional positive-type resist materials, have less edge roughness and dimensional variation, and produce a good pattern shape after exposure. [Means for solving the problem]

[0012] The inventors of the present invention have diligently conducted research to obtain a positive-type resist material that meets the demands of recent years for high resolution and low edge roughness and dimensional variation. As a result, they found that it is necessary to minimize the acid diffusion distance, but this leads to a decrease in sensitivity and a decrease in the resolution of two-dimensional patterns such as hole patterns due to a decrease in dissolution contrast. However, they discovered that by using a polymer containing repeating units having tertiary ester groups with double or triple bonds and aromatic groups substituted with halogen atoms such as fluorine atoms as the base polymer, it is possible to increase the dissolution contrast while simultaneously minimizing the acid diffusion distance. They found that this is particularly effective when used as the base polymer for chemically amplified positive-type resist materials.

[0013] 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 into the base polymer, we can obtain a positive-type resist material that is highly sensitive, has a significantly higher alkali dissolution rate contrast before and after exposure, has a high effect in suppressing acid diffusion, has high resolution, and exhibits good pattern shape, edge roughness, and dimensional uniformity (CDU) after exposure, making it particularly suitable as a material for forming fine patterns in ultra-large-scale integrated circuits (ULSIs) or photomasks. This led to the completion of the present invention.

[0014] In other words, the present invention provides the following positive-type resist material and pattern formation method. 1. A positive-type resist material comprising a base polymer containing repeating units represented by the following formula (a). [ka] [In the formula, R A This is either a hydrogen atom or a methyl group. X 1 This is a linking group having 1 to 12 carbon atoms that includes a single bond, a phenylene group or a naphthylene group, or at least one selected from an ester bond, an ether bond, and a lactone ring. R is a group represented by the following formula (a1). [ka] (In the formula, R 1 R is a linear or branched aliphatic hydrocarbyl group having 1 to 6 carbon atoms, which may contain an oxygen atom. 2 R is a linear or branched unsaturated aliphatic hydrocarbyl group having 2 to 6 carbon atoms, which may contain an oxygen atom. 1 and R 2 These elements may bond with each other to form a ring with 5 to 12 carbon atoms, together with the carbon atoms to which they are bonded. R 3 These are C1-C4 alkyl groups substituted with halogen atoms, cyano groups, fluorine atoms, C1-C4 alkoxy groups substituted with fluorine atoms, or C1-C4 alkylthio groups substituted with fluorine atoms. R 4 is an alkyl group having 1 to 4 carbon atoms. m is an integer from 1 to 5, and n is an integer from 0 to 4. However, 1 ≤ m + n ≤ 5. The dashed line is a bond.)] 2. The positive resist material according to 1, wherein the base polymer further contains at least one selected from a repeating unit in which a hydrogen atom of a carboxy group is substituted with an acid labile group other than the group represented by the formula (a1) and a repeating unit in which a hydrogen atom of a phenolic hydroxy group is substituted with an acid labile group. 3. The positive resist material according to 2, wherein the repeating unit in which a hydrogen atom of a carboxy group is substituted with an acid labile group other than the group represented by the formula (a1) is represented by the following formula (b1), and the repeating unit in which a hydrogen atom of a phenolic hydroxy group is substituted with an acid labile group is represented by the following formula (b2).

Chemical formula

[0015] The positive-type resist material of the present invention can enhance the decomposition efficiency of the acid generator, resulting in a high effect in suppressing acid diffusion, high sensitivity, high resolution, and good pattern shape, edge roughness, and CDU after exposure. Therefore, due to these excellent properties, it is extremely practical and is particularly useful as a material for forming fine patterns in photomasks for ultra-large-scale integrated circuits (ULSIs) or by EB writing, and as a pattern-forming material for EB or EUV exposure. The positive-type resist material of the present invention can be applied not only to lithography in semiconductor circuit formation, but also to the formation of mask circuit patterns, micromachines, and thin-film magnetic head circuits. [Modes for carrying out the invention]

[0016] [Positive-type resist material] The positive resist material of the present invention contains a repeating unit represented by the following formula (a) (hereinafter also referred to as repeating unit a). [ka]

[0017] In formula (a), R A X is a hydrogen atom or a methyl group. 1 This is a linking group having 1 to 12 carbon atoms that includes a single bond, a phenylene group or a naphthylene group, or at least one selected from an ester bond, an ether bond, and a lactone ring.

[0018] In equation (a), R is the group represented by the following equation (a1). [ka]

[0019] In formula (a1), R 1 R is a linear or branched aliphatic hydrocarbyl group having 1 to 6 carbon atoms, which may contain an oxygen atom. 2R is a linear or branched unsaturated aliphatic hydrocarbyl group having 2 to 6 carbon atoms, which may contain an oxygen atom. 1 and R 2 These may bond with each other to form a ring with 5 to 12 carbon atoms, together with the carbon atoms to which they are bonded. 3 This is a C1-C4 alkyl group substituted with a halogen atom, a cyano group, a fluorine atom, a C1-C4 alkoxy group substituted with a fluorine atom, or a C1-C4 alkylthio group substituted with a fluorine atom. 4 m is an alkyl group having 1 to 4 carbon atoms. m is an integer from 1 to 5, and n is an integer from 0 to 4, where 1 ≤ m + n ≤ 5. The dashed lines represent bonds.

[0020] R 1 The aliphatic hydrocarbyl group having 1 to 6 carbon atoms, represented by , may be saturated or unsaturated. Specific examples include alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, and hexyl groups; alkenyl groups having 2 to 6 carbon atoms such as vinyl, 1-propenyl, 2-propenyl, butenyl, pentenyl, and hexenyl groups; and alkynyl groups having 2 to 6 carbon atoms such as ethynyl, 1-propynyl, 2-propynyl, butynyl, pentynyl, and hexynyl groups. 2 Specific examples of unsaturated aliphatic hydrocarbyl groups with 2 to 6 carbon atoms, represented by the formula, include vinyl groups, 1-propenyl groups, 2-propenyl groups, butenyl groups, pentenyl groups, hexenyl groups, etc. 2 Alkenyl groups with up to 6 carbon atoms; such as ethynyl group, 1-propynyl group, 2-propynyl group, butynyl group, pentynyl group, hexynyl group, etc. 2 Examples include alkynyl groups of ~6.

[0021] R 1 and R 2Examples of rings having 5 to 12 carbon atoms that can be formed by the bonding of these atoms with the carbon atoms to which they are bonded include cyclopentene rings, methylcyclopentene rings, dimethylcyclopentene rings, ethylcyclopentene rings, ethylmethylcyclopentene rings, cyclohexene rings, methylcyclohexene rings, dimethylcyclohexene rings, ethylmethylcyclohexene rings, isopropylmethylcyclohexene rings, and cycloheptene rings.

[0022] R 3 Examples of halogen atoms represented by this formula include fluorine, chlorine, bromine, and iodine atoms.

[0023] R 3 Examples of C1-C4 alkyl groups substituted with a fluorine atom include trifluoromethyl, pentafluoroethyl, and hexafluoroisopropyl groups. Examples of C1-C4 alkoxy groups substituted with a fluorine atom include trifluoromethoxy, pentafluoroethoxy, and hexafluoroisopropoxy groups. Examples of C1-C4 alkylthio groups substituted with a fluorine atom include trifluoromethylthio groups.

[0024] R 4 Examples of C1-C4 alkyl groups represented by include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups.

[0025] The bases represented by equation (a1) include, but are not limited to, those listed below. In the following equation, the dashed lines represent bonds. [ka]

[0026] [ka]

[0027] [ka]

[0028] [ka]

[0029] [ka]

[0030] [ka]

[0031] [ka]

[0032] [ka]

[0033] Examples of monomers that give the repeating unit represented by formula (a) are, but are not limited to, those listed below. Note that in the following formula, R A And R are the same as described above. [ka]

[0034] [ka]

[0035] The repeating unit a has a tertiary ester group bonded to an aromatic group substituted with an electron-withdrawing group and a double or triple bond. Since such tertiary ester groups are highly effective in suppressing swelling in alkaline developers, using a base polymer containing repeating unit a results in a resist film with high dissolution contrast and low swelling properties.

[0036] The base polymer may further contain repeating units in which the hydrogen atoms of the carboxyl group are substituted with an acid-unstable group other than the group represented by formula (a1) (hereinafter also referred to as repeating unit b1) and / or repeating units in which the hydrogen atoms of the phenolic hydroxyl group are substituted with an acid-unstable group (hereinafter also referred to as repeating unit b2) in order to further enhance the solubility contrast.

[0037] Examples of repeating units b1 and b2 include those represented by the following formulas (b1) and (b2), respectively. [ka]

[0038] In equations (b1) and (b2), 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 at least one of a single bond, a phenylene group or a naphthylene group, or an ester bond, an ether bond, and a lactone ring. 2 These are single bonds, ester bonds, or amide bonds. 3 These are single bonds, ether bonds, or ester bonds. 11 R is an acid-unstable group other than the group represented by formula (a1). 12 R is an acid-unstable group. 13 R is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 14 a is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and some of its -CH2- may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer from 0 to 4, where 1 ≤ a + b ≤ 5.

[0039] 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 and R 11 This is the same as described above. [ka]

[0040] [ka]

[0041] Examples of monomers that give repeating unit b2 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]

[0042] R 11 or R 12 Various acid-unstable groups can be selected, but examples include those represented by the following formulas (AL-1) to (AL-3). [ka] (In the equation, dashed lines represent connections.)

[0043] In equation (AL-1), c is an integer between 0 and 6. L1 This refers to a tertiary hydrocarbyl group having 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms; a trihydrocarbylsilyl 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 formula (AL-3). A tertiary hydrocarbyl group refers to a group obtained by the removal of a hydrogen atom from a tertiary carbon atom of a hydrocarbon.

[0044] 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.

[0045] Examples of acid-unstable groups represented by 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.

[0046] Furthermore, other acid-unstable groups represented by formula (AL-1) include those represented by the following formulas (AL-1)-1 to (AL-1)-10. [ka] (In the equation, dashed lines represent connections.)

[0047] In equations (AL-1)-1 to (AL-1)-10, c is the same as described above. L8 Each of these is independently a saturated hydrocarbyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. L9 R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. L10 This 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.

[0048] In formula (AL-2), R L2 and R L3 Each of these is independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic, and specific examples include a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, cyclopentyl group, cyclohexyl group, 2-ethylhexyl group, n-octyl group, and the like.

[0049] In formula (AL-2), R L4 This is a hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, which may contain heteroatoms. 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 these hydrogen atoms may be substituted with hydroxyl groups, alkoxy groups, oxo groups, amino groups, alkylamino groups, etc. Examples of such substituted saturated hydrocarbyl groups are shown below. [ka] (In the equation, dashed lines represent connections.)

[0050] R L2 and R L3 And, R L2 and R L4 or RL3 and R L4 and R may combine with each other to form a ring together with the carbon atom to which they are attached, or with a carbon atom and an oxygen atom. In this case, R involved in the formation of the ring L2 and R L3 , R L2 and R L4 , or R L3 and R L4 are each independently an alkanediyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms. The number of carbon atoms in the ring formed by their combination is preferably 3 to 10, more preferably 4 to 10.

[0051] Among the acid-labile groups represented by formula (AL-2), linear or branched ones include, but are not limited to, those represented by the following formulas (AL-2)-1 to (AL-2)-69. In the following formulas, the dashed line represents a bond.

Chemical formula

[0052]

Chemical formula

[0053]

Chemical formula

[0054]

Chemical formula

[0055] Among the acid-labile groups represented by formula (AL-2), cyclic ones include a tetrahydrofuran-2-yl group, a 2-methyltetrahydrofuran-2-yl group, a tetrahydropyran-2-yl group, a 2-methyltetrahydropyran-2-yl group, and the like.

[0056] Examples of the acid-labile group include a group represented by the following formula (AL-2a) or (AL-2b). The base polymer may be crosslinked intermolecularly or intramolecularly by the acid-labile group. [Chemical formula] (In the formula, the dashed line represents a bond.)

[0057] In formula (AL-2a) or (AL-2b), R L11 and R L12 are each 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 may be bonded to each other to form a ring together with the carbon atom to which they are bonded. In this case, R L11 and R L12 are each independently an alkanediyl group having 1 to 8 carbon atoms. R L13 are each independently a saturated hydrocarbylene group having 1 to 10 carbon atoms. The saturated hydrocarbylene group may be linear, branched or cyclic. d and e are each independently an integer of 0 to 10, preferably an integer of 0 to 5, and f is an integer of 1 to 7, preferably an integer of 1 to 3.

[0058] In formula (AL-2a) or (AL-2b), L A is a (f + 1)-valent aliphatic saturated hydrocarbon group having 1 to 50 carbon atoms, a (f + 1)-valent alicyclic saturated hydrocarbon group having 3 to 50 carbon atoms, a (f + 1)-valent aromatic hydrocarbon group having 6 to 50 carbon atoms or a (f + 1)-valent heterocyclic group having 3 to 50 carbon atoms. Also, a part of -CH2- of these groups may be substituted with a group containing a hetero atom, and a part of the hydrogen atoms of these groups may be substituted with a hydroxy group, a carboxy group, an acyl group or a fluorine atom. As L A , a saturated hydrocarbon group such as a saturated hydrocarbylene group having 1 to 20 carbon atoms, a trivalent saturated hydrocarbon group, a tetravalent saturated hydrocarbon group, an arylene group having 6 to 30 carbon atoms, etc. is preferable. The saturated hydrocarbon group may be linear, branched or cyclic. L BThese are -C(=O)-O-, -NH-C(=O)-O-, or -NH-C(=O)-NH-.

[0059] Examples of crosslinked acetal groups represented by formula (AL-2a) or (AL-2b) include groups represented by the following formulas (AL-2)-70 to (AL-2)-77. [ka] (In the equation, dashed lines represent connections.)

[0060] In 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.

[0061] Examples of groups represented by formula (AL-3) include tert-butyl group, 1,1-diethylpropyl group, 1-ethylnorbonyl group, 1-methylcyclopentyl group, 1-ethylcyclopentyl group, 1-isopropylcyclopentyl group, 1-methylcyclohexyl group, 2-(2-methyl)adamantyl group, 2-(2-ethyl)adamantyl group, and tert-pentyl group.

[0062] In addition, the groups represented by formula (AL-3) include those represented by the following formulas (AL-3)-1 to (AL-3)-19. [ka] (In the equation, dashed lines represent connections.)

[0063] In equations (AL-3)-1 to (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.

[0064] Furthermore, examples of acid-unstable groups include those represented by the following formulas (AL-3)-20 or (AL-3)-21. The polymer may be intramolecularly or intermolecularly crosslinked by these acid-unstable groups. [ka] (In the equation, dashed lines represent connections.)

[0065] In equations (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.

[0066] Examples of monomers that give repeating units containing an acid-unstable group represented by formula (AL-3) include (meth)acrylic acid esters containing the exo-isomer structure represented by the following formula (AL-3)-22. [ka]

[0067] In 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 are hydrocarbylene groups that may bond with each other to form a ring with the carbon atoms to which they are bonded, and in this case, the groups involved in bonding may 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 two adjacent carbon atoms bond without any intervening element, forming a double bond. Furthermore, this formula also represents enantiomers.

[0068] Here, examples of monomers represented by 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 AThis is the same as described above. [ka]

[0069] Examples of monomers that give repeating units containing an acid-unstable group represented by formula (AL-3) include (meth)acrylic acid esters containing a franziyl group, a tetrahydrofranziyl group, or an oxanorbornanediyl group, represented by the following formula (AL-3)-23. [ka]

[0070] In 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 hydrogen atoms or heteroatoms. The hydrocarbyl group may be linear, branched, or cyclic. Specific examples include a saturated C1-C10 hydrocarbyl group.

[0071] The monomers represented by formula (AL-3)-23 include, but are not limited to, those listed below. 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]

[0072] [ka]

[0073] The base polymer may further contain repeating units c comprising a hydroxyl group, a carboxyl group, a lactone ring, a carbonate bond, a thiocarbonate bond, a carbonyl group, a cyclic acetal group, an ether bond, an ester bond, a sulfonic acid ester bond, a cyano group, an amide bond, and an adhesive group selected from -OC(=O)-S- and -OC(=O)-NH-.

[0074] Examples of monomers that give repeating units c 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]

[0075] [ka]

[0076] [ka]

[0077] [ka]

[0078] [ka]

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] [ka]

[0083] [ka]

[0084] [ka]

[0085] The base polymer may further contain at least one selected from the repeating units represented by the following formula (d1) (hereinafter also referred to as repeating unit d1), the repeating unit represented by the following formula (d2) (hereinafter also referred to as repeating unit d2), and the repeating unit represented by the following formula (d3) (hereinafter also referred to as repeating unit d3). [ka]

[0086] In equations (d1) to (d3), R A Each of these is independently either a hydrogen atom or a methyl group. 1 This refers to a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or -OZ 11 -, -C(=O)-OZ 11 -or -C(=O)-NH-Z 11 - is Z 11 This is an aliphatic hydrocarbylene group, phenylene group, naphthylene group having 1 to 6 carbon atoms, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 2 These are single bonds or ester bonds. 3 This is a single bond, -Z 31-C(=O)-O-, -Z 31 -O- or -Z 31 -O-C(=O)-. Z 31 Z is an aliphatic hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, a bromine atom or an iodine atom. Z 4 Z is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group or a carbonyl group. Z 5 Z is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -O-Z 51 -, -C(=O)-O-Z 51 - or -C(=O)-NH-Z 51 -. Z 51 Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom or a hydroxy group. Note that Z 1 Z 11 Z 31 and Z 51 The aliphatic hydrocarbylene group represented by Z may be saturated or unsaturated, and may be linear, branched or cyclic.

[0087] In formulas (d1) to (d3), R 21 ~R 28 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include R in formulas (1-1) and (1-2) described later 101 ~R 105Examples similar to those exemplified in the description can be given. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, and nitrogen atoms, and as a result, it may contain a hydroxyl group, fluorine atom, chlorine atom, bromine atom, iodine atom, cyano group, nitro group, carbonyl group, ether bond, ester bond, sulfonic acid ester bond, carbonate bond, lactone ring, sultone ring, carboxylic acid anhydride (-C(=O)-OC(=O)-), haloalkyl group, etc. 23 and R 24 or R 26 and R 27 These 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 formula (1-1) described later. 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.

[0088] In formula (d1), M - This is a non-nucleophilic counterion. Examples of the aforementioned non-nucleophilic counterions include halide ions such as chloride ions and bromide ions, fluoroalkyl sulfonate ions such as triflate ions, 1,1,1-trifluoroethanesulfonate ions and nonafluorobutanesulfonate ions, aryl sulfonate ions such as tosylate ions, benzenesulfonate ions, 4-fluorobenzenesulfonate ions and 1,2,3,4,5-pentafluorobenzenesulfonate ions, alkyl sulfonate ions such as mesylate ions and butanesulfonate ions, imide ions such as bis(trifluoromethylsulfonyl)imide ions, bis(perfluoroethylsulfonyl)imide ions and bis(perfluorobutylsulfonyl)imide ions, and methide ions such as tris(trifluoromethylsulfonyl)methide ions and tris(perfluoroethylsulfonyl)methide ions.

[0089] Examples of the non-nucleophilic counter ion further include sulfonic acid ions in which the α-position is substituted with a fluorine atom and represented by the following formula (d1-1), sulfonic acid ions in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group and represented by the following formula (d1-2), and the like. [Chemical formula]

[0090] In formula (d1-1), R 31 is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain an ether bond, an ester bond, a carbonyl group, a lactone ring, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same ones as those exemplified as the hydrocarbyl group represented by R 111 in formula (1A') described later.

[0091] In formula (d1-2), R 32 is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, or a hydrocarbyl carbonyl group having 2 to 30 carbon atoms, and the hydrocarbyl group and the hydrocarbyl carbonyl group may contain an ether bond, an ester bond, a carbonyl group, or a lactone ring. The hydrocarbyl moiety of the hydrocarbyl group and the hydrocarbyl carbonyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same ones as those exemplified as the hydrocarbyl group represented by R 111 in formula (1A') described later.

[0092] Examples of the cation of the monomer that gives the repeating unit d1 include, but are not limited to, the following. In the following formula, R A is the same as described above. [Chemical formula]

[0093] Specific examples of the cation of the monomer that gives the repeating unit d2 or d3 include the same ones as those exemplified as the cation of the sulfonium salt represented by the formula (1-1) described later.

[0094] Examples of the anion of the monomer that gives the repeating unit d2 include, but are not limited to, the following. In the following formulas, R A is the same as described above.

Chemical formula

[0095]

Chemical formula

[0096]

Chemical formula

[0097]

Chemical formula

[0098]

Chemical formula

[0099]

Chemical formula

[0100]

Chemical formula

[0101]

Chemical formula

[0102]

Chemical formula

[0103] [ka]

[0104] [ka]

[0105] Examples of monomer anions that give the repeating unit d3 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]

[0106] [ka]

[0107] The repeating units d1 to d3 function as acid generators. By binding the acid generators 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 generators improves LWR and CDU. When using a base polymer containing repeating units d1 to d3 (i.e., a polymer-bound type acid generator), the addition of the additive-type acid generator described later can be omitted.

[0108] The base polymer may contain repeating units e other than those described above. Examples of repeating units e include those derived from styrene, vinylnaphthalene, acenaphthylene, indene, coumarin, coumarone, and the like.

[0109] In the base polymer, the content ratios of the repeating units a, b1, b2, c, d1, d2, d3, and e are preferably 0 < a < 1.0, 0 ≤ b1 ≤ 0.9, 0 ≤ b2 ≤ 0.9, 0 ≤ b1 + b2 ≤ 0.9, 0 ≤ c ≤ 0.9, 0 ≤ d1 ≤ 0.5, 0 ≤ d2 ≤ 0.5, 0 ≤ d3 ≤ 0.5, 0 ≤ d1 + d2 + d3 ≤ 0.5, and 0 ≤ e ≤ 0.5; more preferably 0.01 ≤ a ≤ 0.8, 0 ≤ b1 ≤ 0.8, 0 ≤ b2 ≤ 0.8, 0 ≤ b1 + b2 ≤ 0.8, 0 ≤ c ≤ 0.8, 0 ≤ d1 ≤ 0.4, 0 ≤ d2 ≤ 0.4, 0 ≤ d3 ≤ 0.4, 0 ≤ d1 + d2 + d3 ≤ 0.4, and 0 ≤ e ≤ 0.4; still more preferably 0.02 ≤ a ≤ 0.7, 0 ≤ b1 ≤ 0.7, 0 ≤ b2 ≤ 0.7, 0 ≤ b1 + b2 ≤ 0.7, 0 ≤ c ≤ 0.7, 0 ≤ d1 ≤ 0.3, 0 ≤ d2 ≤ 0.3, 0 ≤ d3 ≤ 0.3, 0 ≤ d1 + d2 + d3 ≤ 0.3, and 0 ≤ e ≤ 0.3. However, a + b1 + b2 + c + d1 + d2 + d3 + e = 1.0.

[0110] To synthesize the base polymer, for example, monomers providing the above-mentioned repeating units may be heated in an organic solvent with a radical polymerization initiator added thereto to perform polymerization.

[0111] Examples of the organic solvent used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, dioxane, etc. Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), benzoyl peroxide, lauroyl peroxide, etc. The temperature during polymerization is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

[0112] When copolymerizing a monomer containing a hydroxy group, the hydroxy group may be substituted with an acetal group that is easily deprotected by an acid such as an ethoxyethoxy group before polymerization and then deprotected with a weak acid and water after polymerization, or may be substituted with an acetyl group, a formyl group, a pivaloyl group, etc. and then subjected to alkaline hydrolysis after polymerization.

[0113] 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.

[0114] 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.

[0115] The base polymer has a polystyrene-based weight-average molecular weight (Mw) of 1,000 to 500,000, more preferably 2,000 to 30,000, determined by gel permeation chromatography (GPC) using THF as a solvent. If Mw is too low, the resist material will have poor heat resistance, and if it is too high, its alkali solubility will decrease, making it more likely for the trailing phenomenon to occur after pattern formation.

[0116] Furthermore, if the molecular weight distribution (Mw / Mn) of the base polymer 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 base polymer be narrowly dispersed, between 1.0 and 2.0, and particularly between 1.0 and 1.5.

[0117] The base polymer may contain two or more polymers with different composition ratios, Mw, and Mw / Mn. Alternatively, a polymer containing repeating unit a may be blended with a polymer that does not contain repeating unit a but contains repeating units b1 and / or b2.

[0118] [Acid Generator] The positive resist material 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 the acid-unstable groups of the base polymer.

[0119] Examples of the acid-generating agent include compounds that generate acid in response to active light or radiation (photoacid generators). The photoacid generator is not particularly limited as long as it is a compound that generates acid upon irradiation with high-energy rays, 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 Publication No. 2008-111103.

[0120] Furthermore, sulfonium salts represented by the following formula (1-1) and iodonium salts represented by the following formula (1-2) can also be suitably used as photoacid generators. [ka]

[0121] In equations (1-1) and (1-2), R 101 ~R 105 Each of these is independently a C1-C20 hydrocarbyl group which may contain a halogen atom or a heteroatom.

[0122] Examples of the halogen atoms mentioned above include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0123] R 101 ~R 105The hydrocarbyl group, represented by , having 1 to 20 carbon atoms, may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C20 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl; C3-C20 cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; C2-C20 alkenyl groups such as vinyl, propenyl, butenyl, and hexenyl; and ethynyl groups. Examples include alkynyl groups with 2 to 20 carbon atoms, such as propynyl and butynyl groups; cyclic unsaturated aliphatic hydrocarbyl groups with 3 to 20 carbon atoms, such as cyclohexenyl and norbornenyl groups; aryl groups with 6 to 20 carbon atoms, such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, and tert-butylnaphthyl groups; aralkyl groups with 7 to 20 carbon atoms, such as benzyl and phenethyl groups; and groups obtained by combining these.

[0124] Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0125] Also, R 101 and R 102 These elements may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, the ring is preferably structured as shown below. [ka] (In the formula, the dashed line represents R 103 (This is a combination of the two.)

[0126] Examples of cations of the sulfonium salt represented by formula (1-1) include, but are not limited to, those listed below. [ka]

[0127] [ka]

[0128] [ka]

[0129] [ka]

[0130]

change

[0131]

change

[0132]

change

[0133]

change

[0134]

change

[0135]

change

[0136]

change

[0137]

change

[0138]

change

[0139]

change

[0140]

change

[0141] [ka]

[0142] [ka]

[0143] [ka]

[0144] [ka]

[0145] [ka]

[0146] [ka]

[0147] [ka]

[0148] [ka]

[0149] [ka]

[0150] The cations of the iodonium salt represented by formula (1-2) include, but are not limited to, those listed below. [ka]

[0151] [ka]

[0152] In equations (1-1) and (1-2), Xa - This is an anion selected from the following formulas (1A) to (1D). [ka]

[0153] In 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 formula (1A') described later. 111 Examples of hydrocarbyl groups represented by the symbol shown are similar to those exemplified.

[0154] The anion represented by formula (1A) is preferably the one represented by formula (1A') below. [ka]

[0155] In formula (1A'), R HF R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 111 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.

[0156] R 111The hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include C1-C38 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and eicosanyl; and cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, and norbornyl groups. Examples include cyclic saturated hydrocarbyl groups with 3 to 38 carbon atoms, such as norbornylmethyl group, tricyclodecanyl group, tetracyclododecanyl group, tetracyclododecanylmethyl group, and dicyclohexylmethyl group; unsaturated aliphatic hydrocarbyl groups with 2 to 38 carbon atoms, such as allyl group and 3-cyclohexenyl group; aryl groups with 6 to 38 carbon atoms, such as phenyl group, 1-naphthyl group, and 2-naphthyl group; aralkyl groups with 7 to 38 carbon atoms, such as benzyl group and diphenylmethyl group; and groups obtained by combining these.

[0157] Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. Examples of hydrocarbyl groups containing heteroatoms 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.

[0158] For details on the synthesis of sulfonium salts containing the anion represented by formula (1A'), please refer to Japanese Patent Publication No. 2007-145797, Japanese Patent Publication No. 2008-106045, Japanese Patent Publication No. 2009-7327, Japanese Patent Publication No. 2009-258695, etc. Also, sulfonium salts described in Japanese Patent Publication No. 2010-215608, Japanese Patent Publication No. 2012-41320, Japanese Patent Publication No. 2012-106986, Japanese Patent Publication No. 2012-153644, etc., can be suitably used.

[0159] Examples of anions represented by formula (1A) include those similar to those exemplified as anions represented by formula (1A) in Japanese Patent Publication No. 2018-197853.

[0160] In formula (1B), R fb1 and R fb2 Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may each 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 formula (1A'). 111 Examples of hydrocarbyl groups represented by R include those similar to those exemplified. 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.

[0161] In formula (1C), R fc1 , R fc2 and R fc3Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may each 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 formula (1A'). 111 Examples of hydrocarbyl groups represented by R include those similar to those exemplified. 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.

[0162] In 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 formula (1A'). 111 Examples of hydrocarbyl groups represented by the same formula as those exemplified above include those shown.

[0163] The synthesis of sulfonium salts containing the anion represented by formula (1D) is described in detail in Japanese Patent Publication No. 2010-215608 and Japanese Patent Publication No. 2014-133723.

[0164] Examples of anions represented by formula (1D) include those similar to those exemplified as anions represented by formula (1D) in Japanese Patent Publication No. 2018-197853.

[0165] Furthermore, the photoacid generator containing the anion represented by formula (1D) does not have a fluorine atom 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 base polymer. Therefore, it can be used as a photoacid generator.

[0166] As a photoacid generator, one represented by the following formula (2) can also be suitably used. [ka]

[0167] In formula (2), R 201 and R 202 Each of these is independently a hydrocarbyl group having 1 to 30 carbon atoms, which may contain a halogen atom or a heteroatom. 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 formula (1-1). 101 and R 102 Examples of rings that can be formed when these atoms bond together with the sulfur atom to which they bond are similar to those exemplified.

[0168] R 201 and R 202The hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, 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 having 3 to 30 carbon atoms, such as decanyl and adamantyl groups; aryl groups having 6 to 30 carbon atoms, such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, tert-butylnaphthyl, and anthracenyl groups; and groups obtained by combining these. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0169] R 203The hydrocarbylene group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkane diyl groups with 1 to 30 carbon atoms, such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group, etc.; cyclopentanediyl group, cyclohex Examples include cyclic saturated hydrocarbylene groups having 3 to 30 carbon atoms, such as xanediyl, norbornanediyl, and adamantanediyl groups; arylene groups having 6 to 30 carbon atoms, such as phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, n-propylnaphthylene, isopropylnaphthylene, n-butylnaphthylene, isobutylnaphthylene, sec-butylnaphthylene, and tert-butylnaphthylene; and groups obtained by combining these. Furthermore, some or all of the hydrogen atoms of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- groups of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, the material may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. The heteroatom is preferably an oxygen atom.

[0170] In formula (2), LC 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 R 203 Examples of hydrocarbylene groups represented by the same formula as those exemplified above include the same groups as those shown.

[0171] In 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.

[0172] In equation (2), k is an integer between 0 and 3.

[0173] The photoacid generator represented by formula (2) is preferably the one represented by formula (2') below. [ka]

[0174] In formula (2'), L C This is 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 formula (1A'). 111 Examples of hydrocarbyl groups represented by the formula shown are similar to those exemplified. x and y are each independent integers from 0 to 5, and z is an integer from 0 to 4.

[0175] Examples of photoacid generators represented by formula (2) include those similar to those exemplified as photoacid generators represented by formula (2) in Japanese Patent Publication No. 2017-026980.

[0176] Among the photoacid generators, those containing an anion represented by formula (1A') or (1D) are particularly preferred because they exhibit low acid diffusion and excellent solubility in solvents. Furthermore, those represented by formula (2') are particularly preferred because they exhibit extremely low acid diffusion.

[0177] As the photoacid generator, a sulfonium salt or iodonium salt containing an anion having an aromatic ring substituted with an iodine or bromine atom can also be used. Examples of such salts are those represented by the following formulas (3-1) or (3-2). [ka]

[0178] In equations (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.

[0179] In equations (3-1) and (3-2), X BI These atoms are iodine atoms or bromine atoms, and when p and / or q are 2 or greater, they may be the same or different from each other.

[0180] In equations (3-1) and (3-2), L 1 This is a saturated hydrocarbylene group having 1 to 6 carbon atoms, which may contain a single bond, an ether bond, or an ester bond, or an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched, or cyclic.

[0181] In equations (3-1) and (3-2), L 2When p is 1, it is a single bond or a divalent linking group having 1 to 20 carbon atoms, and when p is 2 or 3, it is a (p+1) valent linking group having 1 to 20 carbon atoms, and the linking group may contain an oxygen atom, a sulfur atom, or a nitrogen atom.

[0182] In equations (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 C1-C20 hydrocarbyl group, a C1-C20 hydrocarbyloxy group, a C2-C20 hydrocarbylcarbonyl group, a C2-C20 hydrocarbyloxycarbonyl group, a C2-C20 hydrocarbylcarbonyloxy group, or a C1-C20 hydrocarbylsulfonyloxy group, or -N(R 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D Or -N(R 401C )-C(=O)-OR 401D That is. R 401A and R 401B Each of these is independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 401C 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, 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. 401DThis is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 15 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 hydrocarbyl group, hydrocarbyloxy group, hydrocarbylcarbonyl group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy 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.

[0183] Of these, R 401 Examples include hydroxyl groups, -N(R 401C )-C(=O)-R 401D , -N(R 401C )-C(=O)-OR 401D Fluorine atoms, chlorine atoms, bromine atoms, methyl groups, methoxy groups, etc. are preferred.

[0184] In equations (3-1) and (3-2), Rf 1 ~Rf 4 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 1 and Rf 2 These may combine to form a carbonyl group. In particular, Rf 3 and Rf 4 It is preferable that both are fluorine atoms.

[0185] In equations (3-1) and (3-2), R 402 ~R 406Each of these is a hydrocarbyl group having 1 to 20 carbon atoms, which may independently contain a halogen 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 formulas (1-1) and (1-2), R 101 ~R 105 Examples of hydrocarbyl groups represented by the above are similar to those exemplified. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxyl group, carboxyl group, halogen atom, cyano group, nitro group, mercapto group, sultone ring, sulfo group, or sulfonium salt-containing group, and some of the -CH2- of the hydrocarbyl group may be substituted with an ether bond, ester bond, carbonyl group, amide bond, carbonate bond, or sulfonic acid ester bond. 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 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.

[0186] Examples of cations for the sulfonium salt represented by formula (3-1) are the same as those exemplified for the sulfonium salt represented by formula (1-1). Similarly, examples of cations for the iodonium salt represented by formula (3-2) are the same as those exemplified for the iodonium salt represented by formula (1-2).

[0187] The anions of the onium salt represented by formula (3-1) or (3-2) include, but are not limited to, those listed below. Note that in the following formulas, X BI This is the same as described above. [ka]

[0188] [ka]

[0189]

change

[0190]

change

[0191]

change

[0192]

change

[0193]

change

[0194]

change

[0195]

change

[0196]

change

[0197]

change

[0198]

change

[0199]

change

[0200]

change

[0201]

change

[0202]

change

[0203]

change

[0204]

change

[0205]

change

[0206]

change

[0207]

change

[0208]

change

[0209]

change

[0210] When the positive-type resist material of the present invention contains an additive-type acid generator, its content 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 base polymer. The additive-type acid generator may be used alone or in combination of two or more types. By the base polymer containing repeating units d1 to d3 and / or by the addition of the additive-type acid generator, the positive-type resist material of the present invention can function as a chemically amplified positive-type resist material.

[0211] [Organic solvents] The positive-type resist material 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 the organic solvent 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 Examples include ethers such as monoethyl 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; and lactones such as γ-butyrolactone.

[0212] In the positive-type resist material 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 base polymer. The organic solvent may be used alone or as a mixture of two or more types.

[0213] [Quencher] The positive-type resist material of the present invention may contain a quencher. A quencher is a compound that can prevent the diffusion of acid generated from the acid generator in the resist material to unexposed areas by trapping the acid.

[0214] Examples of the quencher 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, etc. Particularly preferred are primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent 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 Publication No. 3790649. By adding such basic compounds, for example, the diffusion rate of acid in the resist film can be further suppressed or its shape corrected.

[0215] Furthermore, examples of the quencher 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-position fluorinated are necessary to deprotect the acid-unstable group of the carboxylic acid ester, but the sulfonic acid or carboxylic acid with α-position fluorinated is released by salt exchange with an onium salt whose α-position is not fluorinated. Since sulfonic acids and carboxylic acids with α-position fluorinated do not undergo a deprotection reaction, they function as quenchers.

[0216] Examples of such quenchers include the compound represented by formula (4) below (an onium salt of a sulfonic acid whose α-position is not fluorinated) and the compound represented by formula (5) below (an onium salt of a carboxylic acid). [ka]

[0217] In formula (4), R 501 This refers to a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a hydrogen atom or a heteroatom, but excludes those in which the hydrogen atom bonded to the α-carbon atom of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group.

[0218] The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 40 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl groups; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0 2,6] Cyclic saturated hydrocarbyl groups with 3 to 40 carbon atoms, such as decanyl group, adamantyl group, and adamantylmethyl group; alkenyl groups with 2 to 40 carbon atoms, such as vinyl group, allyl group, propenyl group, butenyl group, and hexenyl group; cyclic unsaturated aliphatic hydrocarbyl groups with 3 to 40 carbon atoms, such as cyclohexenyl group; phenyl group, naphthyl group, alkylphenyl group (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-methylmethylphenyl group, 4-methylphenyl group, methylphenyl group, methylphenyl group, 4-methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, methylphenyl group, Examples include aryl groups with 6 to 40 carbon atoms, such as t-butylphenyl group, 4-n-butylphenyl group, dialkylphenyl group (2,4-dimethylphenyl group, 2,4,6-triisopropylphenyl group, etc.), alkylnaphthyl group (methylnaphthyl group, ethylnaphthyl group, etc.), and dialkylnaphthyl group (dimethylnaphthyl group, diethylnaphthyl group, etc.); and aralkyl groups with 7 to 40 carbon atoms, such as benzyl group, 1-phenylethyl group, and 2-phenylethyl group.

[0219] Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. Examples of hydrocarbyl groups containing heteroatoms include heteroaryl groups such as thienyl and indolyl groups; alkoxyphenyl groups such as 4-hydroxyphenyl, 4-methoxyphenyl, 3-methoxyphenyl, 2-methoxyphenyl, 4-ethoxyphenyl, 4-tert-butoxyphenyl, and 3-tert-butoxyphenyl groups; alkoxynaphthyl groups such as methoxynaphthyl, ethoxynaphthyl, n-propoxynaphthyl, and n-butoxynaphthyl groups; dialkoxynaphthyl groups such as dimethoxynaphthyl and diethoxynaphthyl groups; and aryloxoalkyl groups such as 2-phenyl-2-oxoethyl, 2-(1-naphthyl)-2-oxoethyl, and 2-(2-naphthyl)-2-oxoethyl groups.

[0220] In formula (5), R 502 R is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. 502 The hydrocarbyl group represented by R is 501 Examples of hydrocarbyl groups represented by the same formulas as those exemplified above include the following. Other specific examples include fluorine-containing alkyl groups such as trifluoromethyl group, trifluoroethyl group, 2,2,2-trifluoro-1-methyl-1-hydroxyethyl group, and 2,2,2-trifluoro-1-(trifluoromethyl)-1-hydroxyethyl group; and fluorine-containing aryl groups such as pentafluorophenyl group and 4-trifluoromethylphenyl group.

[0221] In equations (4) and (5), MQ +This is an onium cation. The onium cation is preferably a sulfonium cation, an iodonium cation, or an ammonium cation, and more preferably a sulfonium cation or an iodonium cation. The sulfonium cation is the same as that exemplified as the cation of the sulfonium salt represented by formula (1-1). The iodonium cation is the same as that exemplified as the cation of the iodonium salt represented by formula (1-2).

[0222] As a quencher, a sulfonium salt of an iodized benzene ring-containing carboxylic acid represented by the following formula (6) can also be suitably used. [ka]

[0223] In formula (6), R 601 This may be a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, or a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms, or -N(R 601A )-C(=O)-R 601B Or -N(R 601A )-C(=O)-OR 601B That is. R 601A R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 601B This is a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms.

[0224] In equation (6), x' is an integer between 1 and 5. y' is an integer between 0 and 3. z' is an integer between 1 and 3. L 11This is a single bond or a (z'+1) valence linking group having 1 to 20 carbon atoms, and may contain at least one selected from an ether bond, carbonyl group, ester bond, amide bond, sultone ring, lactam ring, carbonate bond, halogen atom, hydroxyl group, and carboxyl group. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, and saturated hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When y' and / or z' is 2 or more, each R 601 They may be the same or different from one another.

[0225] In formula (6), R 602 , R 603 and R 604 Each of these is a hydrocarbyl group having 1 to 20 carbon atoms, which may independently contain a halogen 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 formulas (1-1) and (1-2). 101 ~R 105 Examples of hydrocarbyl groups represented by the above are similar to those exemplified. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxyl group, carboxyl group, halogen atom, oxo group, cyano group, nitro group, sultone ring, sulfo group, or sulfonium salt-containing group, and some of the -CH2- of the hydrocarbyl group may be substituted with an ether bond, ester bond, carbonyl group, amide bond, carbonate bond, or sulfonic acid ester bond. 602 and R 603 These may bond with each other to form a ring with the sulfur atom to which they are bonded.

[0226] A specific example of the compound represented by formula (6) is the one described in Japanese Patent Publication No. 2017-219836. Since iodine atoms have a large absorption of EUV at a wavelength of 13.5 nm, secondary electrons are generated during exposure, and the energy of these secondary electrons is transferred to the acid generator, thereby promoting the decomposition of the quencher and improving sensitivity.

[0227] Another example of the aforementioned quencher is the polymer-type quencher described in Japanese Patent Publication No. 2008-239918. This enhances the rectangularity of the resist pattern by oriented on the surface of the resist film. The polymer-type quencher also has the effect of preventing film thinning of the pattern and rounding of the pattern top when a protective film for immersion lithography is applied.

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

[0229] [Other ingredients] In addition to the components described above, the positive resist material of the present invention may also contain surfactants, dissolution inhibitors, water-repellent enhancers, acetylene alcohols, and the like.

[0230] 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 material can be further improved or controlled. When the positive-type resist material of the present invention contains the surfactant, its content is preferably 0.0001 to 10 parts by mass per 100 parts by mass of the base polymer. The surfactant may be used alone or in combination of two or more types.

[0231] By incorporating a dissolution inhibitor into the positive resist material of the present invention, the difference in dissolution rate between the exposed and unexposed areas can be further increased, thereby further improving the resolution. Examples of the dissolution inhibitor 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, for example, in paragraphs

[0155] to

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

[0232] When the positive resist material of the present invention contains the dissolution inhibitor, its content is preferably 0 to 50 parts by mass, and more preferably 5 to 40 parts by mass, per 100 parts by mass of the base polymer. The dissolution inhibitor may be used alone or in combination of two or more types.

[0233] The water-repellent enhancer improves the water repellency of the resist film surface and can be used in immersion lithography without a topcoat. Preferred water-repellent enhancers include polymers containing alkyl fluoride, polymers 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 enhancer needs to be soluble in an alkaline developer or an organic solvent developer. The aforementioned water-repellent enhancer having a specific 1,1,1,3,3,3-hexafluoro-2-propanol residue exhibits good solubility in the developer. As a water-repellent enhancer, polymers containing repeating units including amino groups or amine salts are highly effective in preventing acid evaporation in the PEB and thus preventing poor hole pattern opening after development. When the positive resist material of the present invention contains a water-repellency enhancer, its content 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 base polymer. The water-repellency enhancer may be used alone or in combination of two or more types.

[0234] Examples of the acetylene alcohols mentioned above include those described in paragraphs

[0179] to

[0182] of Japanese Patent Publication No. 2008-122932. When the positive-type resist material of the present invention contains acetylene alcohols, the content is preferably 0 to 5 parts by mass per 100 parts by mass of the base polymer. The acetylene alcohols may be used individually or in combination of two or more types.

[0235] [Pattern formation method] When the positive-type resist material of the present invention is used in the manufacture of various integrated circuits, known lithography techniques can be applied. For example, a pattern formation method may include a step of forming a resist film on a substrate using the positive-type resist material described above, a step of exposing the resist film with high-energy rays, and a step of developing the exposed resist film using a developer.

[0236] First, the positive resist material 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.

[0237] Next, the resist film is exposed using high-energy rays. Examples of high-energy rays include ultraviolet rays, far-ultraviolet rays, EB rays, EUV rays with wavelengths of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation. When using ultraviolet rays, far-ultraviolet rays, EUV rays, X-rays, soft X-rays, excimer laser light, gamma rays, or synchrotron radiation as high-energy rays, the exposure amount is preferably 1 to 200 mJ / cm², either directly or using a mask to form the desired pattern. 2 To the extent, more preferably 10 to 100 mJ / cm² 2 Irradiate to the extent that the exposure is approximately 0.1 to 100 μC / cm². When using electroluminescent beams (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 positive-type resist material of the present invention is particularly suitable for fine patterning using high-energy rays, including i-rays with a wavelength of 365 nm, KrF excimer laser light, ArF excimer laser light, EB, EUV, X-rays, soft X-rays, gamma rays, and synchrotron radiation, and is especially suitable for fine patterning using EB or EUV.

[0238] After exposure, PEB may be performed on a hot plate or in an oven, preferably at 50-150°C for 10 seconds to 30 minutes, more preferably at 60-120°C for 30 seconds to 20 minutes.

[0239] After exposure or PEB, the exposed resist film is developed using a developer solution of an alkaline aqueous solution, preferably 0.1 to 10% by mass, more preferably 2 to 5% by mass, of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), etc., 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 parts that were irradiated with light dissolve in the developer solution, while the parts that were not exposed do not dissolve, and the desired positive pattern is formed on the substrate.

[0240] Using the aforementioned positive-type resist material, a negative-type pattern can also be obtained by organic solvent development. The developer used in this process may 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 may be used individually or in mixtures of two or more.

[0241] At the end of development, rinsing is performed. 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.

[0242] 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.

[0243] 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.

[0244] 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.

[0245] Examples of aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0246] Rinsing can reduce the occurrence of deformation and defects in the resist pattern. However, rinsing is not always necessary, and omitting it can reduce the amount of solvent used.

[0247] 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 film due to the diffusion of an acid catalyst from the resist film during baking, causing the shrinking agent to adhere to the side walls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds, during which excess shrinking agent is removed and the hole pattern is reduced in size. [Examples]

[0248] 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.

[0249] [1] Synthesis of monomers [Synthesis Example 1-1] Synthesis of Monomer M-1 In a reaction vessel, 9.20 g of starting compound C-1, 8.60 g of triethylamine, and 0.61 g of 4-dimethylaminopyridine were dissolved in 25 mL of acetonitrile. While maintaining the temperature inside the reaction vessel (internal temperature) at 40-60°C, 7.32 g of methacrylate chloride was added dropwise. After stirring at an internal temperature of 60°C for 19 hours, the reaction mixture was cooled, and 20 mL of saturated sodium bicarbonate solution was added to stop the reaction. The target product was extracted with a mixed solvent of 25 mL of toluene, 15 mL of hexane, and 15 mL of ethyl acetate. After a normal aqueous work-up and removal of the solvent by distillation, 10.2 g of monomer M-1 was obtained as a colorless, transparent oil. [ka]

[0250] [Synthesis Examples 1-2 to 1-13] Synthesis of Monomers M-2 to M-13 The monomers M-2 to M-13 below were synthesized using the same method as in Synthesis Example 1-1, except that the starting compound was changed. [ka]

[0251] [ka]

[0252] [2] Polymer synthesis The monomers cM-1, cM-2, PM-1, PM-2, and AM-1 to AM-4 used in the synthesis of the polymer are as follows. The polymer's Mw is a polystyrene-converted value measured by GPC using THF as the solvent. [ka]

[0253] [ka]

[0254] [ka]

[0255] [Synthesis Example 2-1] Synthesis of Polymer P-1 In a 2L flask, 15.2g of monomer M-1, 4.8g of 4-hydroxystyrene, and 40g 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, 1.2g 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 1L 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 P-1. The composition of polymer P-1 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0256] [Synthesis Example 2-2] Synthesis of Polymer P-2 In a 2L flask, 6.6g of monomer M-2, 5.1g of monomer AM-1, 6.0g of 3-hydroxystyrene, and 40g 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, 1.2g 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 1L 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 P-2. The composition of polymer P-2 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0257] [Synthesis Example 2-3] Synthesis of Polymer P-3 In a 2L flask, 13.2g of monomer M-3, 6.0g of 3-hydroxystyrene, and 40g 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, 1.2g 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 1L 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 P-3. The composition of polymer P-3 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0258] [Synthesis Example 2-4] Synthesis of Polymer P-4 In a 2 L flask, 13.6 g of monomer M-4, 4.2 g of 3-hydroxystyrene, 11.9 g of monomer PM-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 P-4. The composition of polymer P-4 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0259] [Synthesis Example 2-5] Synthesis of Polymer P-5 In a 2L flask, 2.8g of monomer M-5, 5.2g of 1-(cyclopropyl-1-yl)-1-methylethyl methacrylate, 3.5g of 3-fluoro-4-(methylcyclohexyloxy)styrene, 4.8g of 3-hydroxystyrene, 11.2g of monomer PM-1, and 40g 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, 1.2g 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 1L 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 P-5. The composition of polymer P-5 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0260] [Synthesis Example 2-6] Synthesis of Polymer P-6 In a 2L flask, 3.6g of monomer M-6, 6.4g of 1-methyl-1-cyclopentyl methacrylate, 4.2g of 4-hydroxystyrene, 11.0g of monomer PM-2, and 40g 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, 1.2g 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 1L 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 P-6. The composition of polymer P-6 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0261] [Synthesis Example 2-7] Synthesis of Polymer P-7 In a 2L flask, 4.6g of monomer M-7, 8.7g of monomer AM-2, 4.2g of 3-hydroxystyrene, 11.0g of monomer PM-2, and 40g 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, 1.2g 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 1L 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 P-7. The composition of polymer P-7 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0262] [Synthesis Example 2-8] Synthesis of Polymer P-8 In a 2L flask, 3.7g of monomer M-8, 8.7g of monomer AM-2, 4.2g of 3-hydroxystyrene, 11.0g of monomer PM-2, and 40g 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, 1.2g 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 1L 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 P-8. The composition of polymer P-8 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0263] [Synthesis Example 2-9] Synthesis of Polymer P-9 In a 2 L flask, 13.9 g of monomer M-9, 4.2 g of 3-hydroxystyrene, 11.9 g of monomer PM-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 P-9. The composition of polymer P-9 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0264] [Synthesis Example 2-10] Synthesis of Polymer P-10 In a 2L flask, 11.6g of monomer M-10, 4.2g of 3-hydroxystyrene, 11.9g of monomer PM-1, and 40g 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, 1.2g 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 1L 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 P-10. The composition of polymer P-10 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0265] [Synthesis Example 2-11] Synthesis of Polymer P-11 In a 2L flask, 6.6g of monomer M-3, 4.5g of monomer AM-3, 5.4g of 3-hydroxystyrene, 0.5g of styrene, and 40g 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, 1.2g 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 1L 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 P-11. The composition of polymer P-11 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0266] [Synthesis Example 2-12] Synthesis of Polymer P-12 In a 2L flask, 6.6g of monomer M-3, 4.5g of monomer AM-4, 5.4g of 3-hydroxystyrene, 0.6g of 4-methoxystyrene, and 40g 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, 1.2g 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 1L 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 P-12. The composition of polymer P-12 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0267] [Synthesis Example 2-13] Synthesis of Polymer P-13 In a 2L flask, 6.6g of monomer M-3, 4.5g of monomer AM-4, 3.0g of 3-hydroxystyrene, 3.0g of 2-styrene, and 40g 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, 1.2g 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 1L 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 P-13. The composition of polymer P-13 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0268] [Synthesis Example 2-14] Synthesis of Polymer P-14 In a 2L flask, 6.1g of monomer M-11, 4.5g of monomer AM-4, 6.0g of 3-hydroxystyrene, and 40g 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, 1.2g 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 1L 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 P-14. The composition of polymer P-14 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0269] [Synthesis Example 2-15] Synthesis of Polymer P-15 In a 2L flask, 12.5g of monomer M-12, 4.2g of 3-hydroxystyrene, 11.9g of monomer PM-1, and 40g 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, 1.2g 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 1L 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 P-15. The composition of polymer P-15 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0270] [Synthesis Example 2-16] Synthesis of Polymer P-16 In a 2L flask, 12.5g of monomer M-13, 4.2g of 3-hydroxystyrene, 11.9g of monomer PM-1, and 40g 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, 1.2g 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 1L 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 P-16. The composition of polymer P-16 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0271] [Comparative Synthesis Example 1] Synthesis of comparative polymer cP-1 The comparative polymer cP-1 was obtained using the same method as in Synthesis Example 2-1, except that monomer cM-1 was used instead of monomer M-1. The composition of comparative polymer cP-1 is 13 C-NMR and 1Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0272] [Comparative Synthesis Example 2] Synthesis of comparative polymer cP-2 The comparative polymer cP-2 was obtained using the same method as in Synthesis Example 2-1, except that monomer cM-2 was used instead of monomer M-1. The composition of comparative polymer cP-2 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0273] [Comparative Synthesis Example 3] Synthesis of Comparative Polymer cP-3 Comparative polymer cP-3 was obtained by the same method as in Synthesis Example 2-1, except that 1-methyl-1-cyclopentyl methacrylate was used instead of monomer M-1. The composition of comparative polymer cP-3 is 13 C-NMR and 1 Mw and Mw / Mn were confirmed by GPC using 1H-NMR. [ka]

[0274] [3] Preparation and evaluation of positive resist materials [Examples 1-16, Comparative Examples 1-3] (1) Preparation of positive-type resist material Positive-type resist materials were prepared by dissolving each component in a solvent containing 50 ppm of PolyFox PF-636 surfactant manufactured by Omnova, as shown in Table 1, and filtering the solution through a 0.2 μm filter.

[0275] In Table 1, the components are as follows: • Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (Diacetone Alcohol) EL (Ethyl Lactate)

[0276] • Acid generators: PAG-1, PAG-2 [ka]

[0277] • Quencher: Q-1~Q-3 [ka]

[0278] (2) EUV lithography evaluation Each positive-type resist material shown in Table 1 was spin-coated onto a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content 43 mass%) manufactured by Shin-Etsu Chemical Co., Ltd. had been formed to a thickness of 20 nm. A resist film with a thickness of 60 nm was fabricated by pre-baking at 105°C for 60 seconds using a hot plate. The resist film was exposed using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, wafer-mounted dimensions of a 46 nm pitch hole pattern mask with a +20% bias). PEB was performed on a hot plate at the temperatures listed in Table 1 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 High-Tech SEM (CG6300), and the CDU was calculated as three times the standard deviation (σ) obtained from these measurements (3σ). The results are shown in Table 1.

[0279] [Table 1]

[0280] As shown in Table 1, the positive-type resist material of the present invention, which includes a base polymer containing repeating units represented by formula (a), exhibited high sensitivity and good CDU.

Claims

1. A positive-type resist material comprising a base polymer containing repeating units represented by the following formula (a). 【Chemistry 1】 [In the formula, R A This is either a hydrogen atom or a methyl group. X 1 This is a linking group having 1 to 12 carbon atoms, containing at least one of a single bond, a phenylene group or a naphthylene group, or an ester bond, an ether bond, and a lactone ring. R is a group represented by the following formula (a1). 【Chemistry 2】 (In the formula, R 1 R is a linear or branched aliphatic hydrocarbyl group having 1 to 6 carbon atoms, which may contain an oxygen atom. 2 R is a linear or branched unsaturated aliphatic hydrocarbyl group having 2 to 6 carbon atoms, which may contain an oxygen atom. 1 and R 2 These elements bond with each other, forming a ring with 5 to 12 carbon atoms together with the carbon atoms to which they are bonded. R 3 These are C1-C4 alkyl groups substituted with halogen atoms, cyano groups, fluorine atoms, C1-C4 alkoxy groups substituted with fluorine atoms, or C1-C4 alkylthio groups substituted with fluorine atoms. R 4 These are alkyl groups having 1 to 4 carbon atoms. m is an integer between 1 and 5, and n is an integer between 0 and 4, where 1 ≤ m + n ≤ 5. The dashed lines represent connecting hands.

2. The positive-type resist material according to claim 1, wherein the base polymer further comprises at least one selected from repeating units in which the hydrogen atoms of a carboxyl group are substituted with an acid-unstable group other than the group represented by formula (a1), and repeating units in which the hydrogen atoms of a phenolic hydroxyl group are substituted with an acid-unstable group.

3. The positive resist material according to claim 2, wherein the repeating unit in which the hydrogen atom of the carboxyl group is substituted with an acid-unstable group other than the group represented by formula (a1) is represented by the following formula (b1), and the repeating unit in which the hydrogen atom of the phenolic hydroxyl group is substituted with an acid-unstable group is represented by the following formula (b2). 【Transformation 3】 (wherein, R A is each independently a hydrogen atom or a methyl group.) Y 1 This is a linking group having 1 to 12 carbon atoms, containing at least one of a single bond, a phenylene group or a naphthylene group, or an ester bond, an ether bond, and a lactone ring. Y 2 These are single bonds, ester bonds, or amide bonds. Y 3 These are single bonds, ether bonds, or ester bonds. R 11 These are acid-unstable groups other than the group represented by formula (a1). R 12 It is an acid-unstable group. R 13 This is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 14 This is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and its -CH 2 - May be partially replaced by an ether bond or an ester bond. a is either 1 or 2. b is an integer between 0 and 4, where 1 ≤ a + b ≤ 5.

4. The positive resist material according to claim 1, wherein the base polymer further comprises repeating units comprising an adhesion group selected from a hydroxyl group, a carboxyl group, a lactone ring, a carbonate bond, a thiocarbonate bond, a carbonyl group, a cyclic acetal group, an ether bond, an ester bond, a sulfonic acid ester bond, a cyano group, an amide bond, -O-C(=O)-S-, and -O-C(=O)-NH-.

5. The positive-type resist material according to claim 1, wherein the base polymer further comprises a repeating unit represented by any of the following formulas (d1) to (d3). 【Chemistry 4】 (In the formula, R A Each of these is independently either a hydrogen atom or a methyl group. Z 1 This is a single bond, or an aliphatic hydrocarbylene group, phenylene group, naphthylene group having 1 to 6 carbon atoms, or a group having 7 to 18 carbon atoms obtained by combining these, or -O-Z 11 -, -C(=O)-O-Z 11 - or -C(=O)-NH-Z 11 - is Z 11 This refers to an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. Z 2 These are single bonds or ester bonds. Z 3 This is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -O-C(=O)-. Z 31 This is an aliphatic hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, an iodine atom, or a bromine atom. Z 4 This is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, or a carbonyl group. Z 5 This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, trifluoromethyl groups, and -O-Z. 51 -, -C(=O)-O-Z 51 - or -C(=O)-NH-Z 51 - is Z 51 This is a phenylene group substituted with an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom, or a hydroxyl group. R 21 ~R 28 Each of these is independently a C1-C20 hydrocarbyl group which may contain a halogen atom or a heteroatom. 23 and R 24 or R 26 and R 27 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. M - (It is a non-nucleophilic counterion.)

6. Furthermore, the positive-type resist material according to claim 1, further comprising an acid generator.

7. Furthermore, the positive-type resist material according to claim 1, further comprising an organic solvent.

8. Furthermore, the positive-type resist material according to claim 1, further comprising a quencher.

9. Furthermore, the positive-type resist material according to claim 1, further comprising a surfactant.

10. A pattern forming method comprising the steps of: forming a resist film on a substrate using a positive-type resist material according to any one of claims 1 to 9; exposing the resist film with a high-energy beam; and developing the exposed resist film using a developer.

11. The pattern forming method according to claim 10, wherein the high-energy ray 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.

Images