Negative resist material and pattern forming method

Abstract

To provide a negative resist material for organic solvent development that has high resolution and improved LWR and CDU, and a patterning method using the same.SOLUTION: A negative resist material comprises a base polymer, two or more polymerizable double bonds in a molecule, a quencher comprising a sulfonium salt having weaker acidity than that of a sulfonic acid with fluorinated α-position and / or β-position of a sulfo group, and an acid generator that generates a sulfonic acid with fluorinated α-position and / or β-position of a sulfo group.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] As LSIs become more highly integrated and faster, pattern rules are becoming increasingly miniaturized. This is due to the increasing popularity of 5G high-speed communications and artificial intelligence (AI), which require high-performance devices to process these. The most advanced miniaturization technology is extreme ultraviolet (EUV) lithography with a wavelength of 13.5 nm, which is currently used to mass-produce 5 nm node devices. Furthermore, the use of EUV lithography is being considered for next-generation 3 nm node devices and the next-generation 2 nm node devices.

[0003] As miniaturization progresses, image blurring due to acid diffusion has become a problem. To ensure resolution in fine patterns with dimensions of 45 nm and smaller, it has been suggested that controlling acid diffusion is important, in addition to improving dissolution contrast, as has been proposed previously (Non-Patent Document 1). However, because chemically amplified resist materials increase sensitivity and contrast through acid diffusion, attempts to minimize acid diffusion by lowering the post-exposure bake (PEB) temperature or shortening the time result in significant decreases in sensitivity and contrast.

[0004] Interference exposure is effective when forming patterns with pitches narrower than the wavelength. In particular, high-contrast light interference between X-direction lines and Y-direction lines generates high-contrast black spots. By combining this with a negative resist material, hole patterns with high dimensional uniformity (CDU) can be formed (Non-Patent Document 2). Non-Patent Document 2 uses a negative resist material that uses a crosslinking agent that reacts between polymers in the presence of acid. Such chemically amplified negative resist materials have the problems of image blurring due to acid diffusion mentioned above, and swelling caused by developer seeping into the partially crosslinked polymers, which leads to pattern collapse and degradation of CDU and line edge roughness (LWR).

[0005] Here, the creation of negative patterns by organic solvent development is a method that has been used for a long time. Cyclized rubber-based resist materials use xylene or the like as a developer, and early chemically amplified resist materials based on poly-tert-butoxycarbonyloxystyrene used anisole as a developer to obtain negative patterns (Non-Patent Document 3).

[0006] A negative pattern can be formed by exposure to ArF excimer laser light and organic solvent development using a chemically amplified resist material whose base polymer is polymethacrylate in which the carboxyl group is substituted with an acid-labile group (Patent Document 1). This organic solvent development process is used in combination with immersion exposure and double patterning using an optical system with an NA exceeding 1 in the manufacture of devices at the 20 nm node and beyond.

[0007] EUV lithography cannot form patterns with a pitch smaller than the exposure wavelength. This is because the NA of EUV exposure is 0.33, which is significantly smaller than the 1.35 of ArF immersion exposure, and the effect of interference exposure is low. The next NA after EUV lithography is 0.55, but even in this generation, negative resist materials do not have an advantage in forming hole patterns.

[0008] Negative patterns are required in EUV lithography when forming isolated patterns or pillar patterns. In this case, the mask has a high proportion of light-shielding areas, which has the advantage of being less susceptible to defects in the mask blanks.

[0009] When forming an isolated pattern or a pillar pattern on a photomask, a negative resist material is preferably used. This is because the patterning area is smaller when a negative resist material is used, which shortens the patterning time and improves throughput. Therefore, high resolution is also required for resist materials used in EB lithography for mask pattern formation.

[0010] Organic solvent development causes less swelling than alkaline aqueous development, which can result in better CDU and LWR. However, it has the problem of lower resolution due to lower dissolution contrast compared to alkaline aqueous development. If a crosslinker that reacts with acid is added to the resist material to increase the dissolution contrast in organic solvent development, the aforementioned swelling problem will also occur in organic solvent development. It is necessary to improve the dissolution contrast without swelling. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-281974 [Non-patent literature]

[0012] [Non-Patent Document 1] SPIE Vol. 6520 65203L-1 (2007) [Non-patent document 2] IEEE IEDM Tech. Digest 61 (1996) [Non-patent document 3] VLSI. Technol. Symp. p86-87 (1982) Summary of the Invention [Problem to be solved by the invention]

[0013] There is a need to develop negative resist materials compatible with organic solvent processes that can reduce line write (LWR) in line patterns and cover density under (CDU) in hole patterns, while also achieving high resolution. To achieve this, they must have low swelling and high contrast during organic solvent development.

[0014] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a negative resist material for organic solvent development that has high resolution and improved LWR and CDU, and a pattern formation method using the same. [Means for solving the problem]

[0015] As a result of extensive research into achieving the above-mentioned object, the inventors of the present invention have found that a resist material comprising a base polymer, an acid generator, and a quencher which is a sulfonium salt of a weak acid having two or more polymerizable double bonds in its molecule undergoes crosslinking of the sulfonium salt upon exposure, thereby enhancing the acid diffusion suppression effect, and also reducing the solubility in organic solvents and improving the dissolution contrast, thereby improving LWR and CDU, providing excellent resolution, and a wide process margin, and have completed the present invention.

[0016] That is, the present invention provides the following negative resist material and pattern forming method. 1. A negative resist material comprising a base polymer, a quencher consisting of a sulfonium salt having two or more polymerizable double bonds in the molecule and having a weaker acidity than sulfonic acid in which the α- and / or β-position of the sulfo group is fluorinated, and an acid generator that generates sulfonic acid in which the α- and / or β-position of the sulfo group is fluorinated. 2. A negative resist material according to 1, wherein the sulfonium salt, which has two or more polymerizable double bonds in the molecule and is weaker in acid than sulfonic acid and in which the α- and / or β-position of the sulfo group is fluorinated, is represented by the following formula (A): [ka] (In the formula, k 1 , m 1 and n 1 is 0≦k 1 ≦4, 1≦m 1 ≦3, 0≦n 1 ≦2, 2≦k 1 +m 1 ≦7 and m 1 +n 1 p is an integer that satisfies =3. 1 is 1 or 2, and q 1 is an integer between 0 and 4, where 1≦p 1 +q 1 ≦5. 1 is an integer between 0 and 5. X - is -SO3 - , -CO2 - , -N - -SO2-R F or -O - R F is a fluorine atom or a fluorinated hydrocarbyl group having 1 to 30 carbon atoms, and the fluorinated hydrocarbyl group may contain at least one bond selected from a hydroxy group, a carboxy group, a carbonyl group, an ether bond, an ester bond and an amide bond. X 1 is a single bond, an ester bond, an ether bond, an amide bond or a urethane bond. X 2 is k 1 is 0 and X - -CO2 - When k is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a hetero atom, 1 is 0 and X - Ga-N - -SO2-R F When k is a hydrogen atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom, 1 is 0 and X - Ga-SO3 - or -O - When k is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom, 1When k is 1, it is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a hetero atom; 1 When is 2, 3 or 4, (k 1 +1)valent hydrocarbon group, provided that X - Ga-SO3 - When X 2 Ha-SO3 - The α- and β-positions of X are not fluorinated, - -O - When -O - The carbon atom to which is attached is not a carbon atom on an aromatic ring. X 3 represents a single bond, an ester bond, an ether bond, an amide bond, a urethane bond, or an alkanediyl group having 1 to 10 carbon atoms, and some of the -CH2- groups in the alkanediyl group may be substituted with ester bonds, ether bonds, amide bonds, or urethane bonds. R 1 ~R 3 are each independently a hydrogen atom, a halogen atom, or a saturated hydrocarbyl group having 1 to 40 carbon atoms, and some or all of the hydrogen atoms of the saturated hydrocarbyl group may be substituted with fluorine atoms or hydroxy groups, some of the -CH2- groups of the saturated hydrocarbyl group may be substituted with ether bonds or ester bonds, and some of the carbon-carbon bonds of the saturated hydrocarbyl group may be double bonds. R 4 and R 5 are each independently a halogen atom, a cyano group, a nitro group, a mercapto group, a sulfo group, a saturated hydrocarbyl group having 1 to 10 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and the saturated hydrocarbyl group and the aralkyl group may contain an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom. 4 or two R's 5 may be bonded to each other to form a ring together with the benzene ring to which they are bonded, and R 4 and R 5 may be bonded to each other to form a ring together with the benzene ring to which they are bonded and the sulfur atom therebetween. 3. The negative resist material of 1 or 2, wherein the acid generator is a sulfonium salt having two or more polymerizable double bonds in the molecule. 4. The negative resist material of 3, wherein the acid generator, a sulfonium salt having two or more polymerizable double bonds in the molecule, is represented by the following formula (B): [ka] (In the formula, k 2 , m 2 and n 2 is 0≦k 2 ≦4, 1≦m 2 ≦3, 0≦n 2 ≦2, 2≦k 2 +m 2 ≦7 and m 2 +n 2 p is an integer that satisfies =3. 2 is 1 or 2, and q 2 is an integer between 0 and 4, where 1≦p 2 +q 2 ≦5. 2 is an integer between 0 and 5. X 5 is a single bond, an ester bond, an ether bond, an amide bond or a urethane bond. X 6 is k 2 When k is 0, it is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom; 2 When k is 1, it is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a hetero atom; 2 When is 2, 3 or 4, (k 2 +1)valent hydrocarbon group. X 7 is a single bond, an ether bond or an ester bond. X 8 represents a single bond, an ester bond, an ether bond, an amide bond, a urethane bond, or an alkanediyl group having 1 to 10 carbon atoms, and some of the -CH2- groups in the alkanediyl group may be substituted with ester bonds, ether bonds, amide bonds, or urethane bonds. R 6~R 8 are each independently a hydrogen atom, a halogen atom, or a saturated hydrocarbyl group having 1 to 40 carbon atoms, and some or all of the hydrogen atoms of the saturated hydrocarbyl group may be substituted with fluorine atoms or hydroxy groups. R 9 and R 10 are each independently a halogen atom, a cyano group, a nitro group, a mercapto group, a sulfo group, a saturated hydrocarbyl group having 1 to 10 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and the saturated hydrocarbyl group and the aralkyl group may contain an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom. 9 or two R's 10 may be bonded to each other to form a ring together with the benzene ring to which they are bonded, and R 9 and R 10 may be bonded to each other to form a ring together with the benzene ring to which they are bonded and the sulfur atom therebetween. Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, and at least one of them is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 may combine to form a carbonyl group.) 5. The negative resist material of any one of 1 to 4, wherein the base polymer contains a repeating unit represented by the following formula (a1): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. Y 1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and containing at least one bond selected from an ester bond, an ether bond, and a lactone ring. R 21 is an acid labile group. 6. A negative resist material according to any one of 1 to 5, further comprising an organic solvent. 7. A negative resist material according to any one of 1 to 6, further comprising a crosslinking agent. 8. A negative resist material according to any one of 1 to 7, further comprising a surfactant. 9. A pattern forming method comprising the steps of forming a resist film on a substrate using a negative resist material according to any one of 1 to 8, exposing the negative resist film to high-energy rays, and developing the exposed negative resist film using an organic solvent developer. 10. The organic solvent developer is selected from the group consisting of 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, isopentyl acetate, 2-methylbutyl acetate, hexyl acetate, butenyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, propyl methyl methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, propyl methyl methyl methyl valerate, methyl pentenoate, methyl crotonate, propyl methyl methyl methyl valerate, methyl pentenoate, methyl crotonate, ethyl ...methyl valerate, methyl pentenoate, methyl crotonate, ethyl propyl methyl methyl methyl methyl valerate, methyl pentenoate, methyl crotonate, ethyl propyl methyl methyl methyl methyl valerate, methyl pentenoate, methyl pentenoate, ethyl propyl methyl methyl methyl methyl valerate, methyl pentenoate, methyl pentenoate, ethyl propyl methyl methyl methyl methyl methyl valerate, methyl 9. A pattern formation method in accordance with claim 9, wherein the compound is one or more selected from the group consisting of methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, and 2-phenylethyl acetate. 11. The pattern formation method of 9 or 10, wherein the high-energy radiation is KrF excimer laser light, ArF excimer laser light, EB, or EUV having a wavelength of 3 to 15 nm. [Effects of the Invention]

[0017] Resist materials containing the base polymer and a quencher made of a sulfonium salt having two or more polymerizable double bonds undergo a crosslinking reaction upon exposure, resulting in low acid diffusion and promoting insolubilization in a developer. This allows the construction of resist materials with high resolution and improved LWR and CDU. DETAILED DESCRIPTION OF THE INVENTION

[0018] [Negative resist material] The negative resist material of the present invention comprises a base polymer, a quencher comprising a sulfonium salt having two or more polymerizable double bonds in the molecule and having a weaker acidity than sulfonic acid in which the α- and / or β-position of the sulfo group is fluorinated, and an acid generator that generates sulfonic acid in which the α- and / or β-position of the sulfo group is fluorinated.

[0019] [Quencher] The quencher is a sulfonium salt that has two or more polymerizable double bonds in the molecule, is fluorinated at the α-position and / or β-position of the sulfo group, and is weaker in acid than sulfonic acid, and is preferably represented by the following formula (A): [ka]

[0020] In formula (A), k 1 , m 1 and n 1 is 0≦k 1 ≦4, 1≦m 1 ≦3, 0≦n 1 ≦2, 2≦k 1 +m 1 ≦7 and m 1 +n 1 p is an integer that satisfies =3. 1 is 1 or 2, and q 1 is an integer between 0 and 4, where 1≦p 1 +q 1 ≦5. 1 is an integer between 0 and 5.

[0021] In formula (A), X - is -SO3 - , -CO2 - , -N - -SO2-R F or -O - R F is a fluorine atom or a fluorinated hydrocarbyl group having 1 to 30 carbon atoms, and the fluorinated hydrocarbyl group may contain at least one bond selected from a hydroxy group, a carboxy group, a carbonyl group, an ether bond, an ester bond and an amide bond.

[0022] In formula (A), X 1 is a single bond, an ester bond, an ether bond, an amide bond or a urethane bond.

[0023] In formula (A), X 2 is k 1 is 0 and X - -CO2 - When k is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a hetero atom, 1 is 0 and X - Ga-N - -SO2-R F When k is a hydrogen atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom, 1 is 0 and X - Ga-SO3 - or -O - When k is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom, 1 When k is 1, it is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a hetero atom; 1 When is 2, 3 or 4, (k 1 +1)valent hydrocarbon group, provided that X - Ga-SO3 - When X 2 Ha-SO3 - The α- and β-positions of X are not fluorinated, - -O - When -O -The carbon atom to which is attached is not a carbon atom on an aromatic ring.

[0024] X 2 a hydrocarbyl group having 1 to 40 carbon atoms, a hydrocarbylene group having 1 to 40 carbon atoms, and a (k 1 The monovalent hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples of the hydrocarbyl group having 1 to 40 carbon atoms include alkyl groups having 1 to 40 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and icosanyl; cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, and tricyclodecyl. Examples of the hydrocarbylene group include cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms, such as an allyl group, a tetracyclododecanyl group, a tetracyclododecanylmethyl group, and a dicyclohexylmethyl group; unsaturated hydrocarbyl groups having 2 to 40 carbon atoms, such as an allyl group, a 3-cyclohexenyl group, and a tetracyclododecenyl group; aryl groups having 6 to 40 carbon atoms, such as a phenyl group, a 1-naphthyl group, and a 2-naphthyl group; aralkyl groups having 7 to 40 carbon atoms, such as a benzyl group and a diphenylmethyl group; hydrocarbyl groups having 20 to 40 carbon atoms and having a steroid skeleton, which may contain a heteroatom; and groups obtained by combining these. Specific examples of the hydrocarbylene group having 1 to 40 carbon atoms include groups obtained by further removing one hydrogen atom from the specific examples of the hydrocarbyl group described above, and the above-mentioned (k) groups having 1 to 40 carbon atoms are also suitable. 1 Specific examples of the +1)valent hydrocarbon group include those obtained by further adding a hydrogen atom to the specific examples of the hydrocarbyl groups described above. 1 Examples of groups include groups obtained by removing one or more groups.

[0025] In addition, the hydrocarbyl group, hydrocarbylene group, and (k 1A part or all of the hydrogen atoms of the (+1)-valent hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and the hydrocarbyl group, hydrocarbylene group and (k 1 A portion of the -CH2- in the monovalent hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, the group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0026] In formula (A), X 3 is a single bond, an ester bond, an ether bond, an amide bond, a urethane bond, or an alkanediyl group having 1 to 10 carbon atoms, and a portion of the -CH2- in the alkanediyl group may be substituted with an ester bond, an ether bond, an amide bond, or a urethane bond. Examples of the alkanediyl group include a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, and a decane-1,10-diyl group.

[0027] In formula (A), R 1 ~R 3 are each independently a hydrogen atom, a halogen atom, or a saturated hydrocarbyl group having 1 to 40 carbon atoms, and some or all of the hydrogen atoms of the saturated hydrocarbyl group may be substituted with fluorine atoms or hydroxy groups, some of the -CH2- groups of the saturated hydrocarbyl group may be substituted with ether bonds or ester bonds, and some of the carbon-carbon bonds of the saturated hydrocarbyl group may be double bonds.

[0028] R 1 ~R 3The saturated hydrocarbyl group having 1 to 40 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include alkyl groups having 1 to 40 carbon atoms, such as a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, 2-ethylhexyl group, nonyl group, undecyl group, tridecyl group, pentadecyl group, heptadecyl group, and eicosanyl group; and cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms, such as a cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, 1-adamantylmethyl group, norbornyl group, norbornylmethyl group, tricyclodecanyl group, tetracyclododecanyl group, tetracyclododecanylmethyl group, and dicyclohexylmethyl group.

[0029] In formula (A), R 4 and R 5 are each independently a halogen atom, a cyano group, a nitro group, a mercapto group, a sulfo group, a saturated hydrocarbyl group having 1 to 10 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and the saturated hydrocarbyl group and the aralkyl group may contain an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom. 4 or two R's 5 may be bonded to each other to form a ring together with the benzene ring to which they are bonded, and R 4 and R 5 may be bonded to each other to form a ring together with the benzene ring to which they are bonded and the sulfur atom therebetween. In this case, the ring preferably has the structure shown below, where the substituents on the aromatic ring are omitted. [ka] (In the formula, the dashed lines represent bonds.)

[0030] X - Ga-SO3 - In this case, examples of the sulfonate anion of the sulfonium salt represented by formula (A) include, but are not limited to, those shown below. [ka]

[0031] [ka]

[0032] [ka]

[0033] X - -CO2 - In this case, examples of the carboxylate anion of the sulfonium salt represented by formula (A) include, but are not limited to, those shown below. [ka]

[0034] [ka]

[0035] [ka]

[0036] [ka]

[0037] [ka]

[0038] [ka]

[0039] [ka]

[0040] [ka]

[0041] [ka]

[0042] [ka]

[0043] [ka]

[0044] [ka]

[0045] [ka]

[0046] [ka]

[0047] X - Ga-N - -SO2-R F In this case, examples of the sulfonamide anion of the sulfonium salt represented by formula (A) include, but are not limited to, those shown below. [ka]

[0048] [ka]

[0049]

change

[0050]

change

[0051]

change

[0052]

change

[0053]

change

[0054]

change

[0055]

change

[0056]

change

[0057]

change

[0058]

change

[0059]

change

[0060] [ka]

[0061] [ka]

[0062] [ka]

[0063] [ka]

[0064] X - -O - In this case, examples of the alkoxide anion of the sulfonium salt represented by formula (A) include, but are not limited to, those shown below. [ka]

[0065] [ka]

[0066] [ka]

[0067] Examples of the sulfonium cation having a polymerizable double bond in the sulfonium salt represented by formula (A) include, but are not limited to, those shown below. [ka]

[0068]

change

[0069]

change

[0070]

change

[0071]

change

[0072]

change

[0073]

change

[0074]

change

[0075]

change

[0076]

change

[0077]

change

[0078]

change

[0079] The sulfonium salt represented by formula (A) can be synthesized by ion-exchanging a sodium salt or ammonium salt of a sulfonic acid, carboxylic acid, sulfonamide, or alcohol that provides the anion with a sulfonium chloride containing the sulfonium cation.

[0080] The sulfonium salt represented by formula (A) not only traps the acid generated from the acid generator described below, but also exhibits strong acid diffusion control ability by increasing its molecular weight through polymerization and crosslinking upon exposure.

[0081] In the negative resist material of the present invention, the content of the quencher composed of a sulfonium salt represented by Formula (A) is preferably 0.1 to 30 parts by mass, and more preferably 0.2 to 20 parts by mass, per 100 parts by mass of the base polymer described below, from the viewpoints of sensitivity and acid diffusion suppression effect.

[0082] [Acid generator] The acid generator generates a sulfonic acid in which the α- and / or β-position of the sulfo group is fluorinated. Such an acid generator is not particularly limited, and conventionally known acid generators can be used.

[0083] As the acid generator, a sulfonium salt having two or more polymerizable double bonds in the molecule is particularly preferred. Such a sulfonium salt is preferably one represented by the following formula (B): [ka]

[0084] In formula (B), k 2 , m 2 and n 2 is 0≦k 2 ≦4, 1≦m 2 ≦3, 0≦n 2 ≦2, 2≦k 2 +m 2 ≦7 and m 2 +n 2 p is an integer that satisfies =3. 2is 1 or 2, and q 2 is an integer between 0 and 4, where 1≦p 2 +q 2 ≦5. 2 is an integer between 0 and 5.

[0085] In formula (B), X 5 is a single bond, an ester bond, an ether bond, an amide bond or a urethane bond.

[0086] In formula (B), X 6 is k 2 When k is 0, it is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom; 2 When k is 1, it is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a hetero atom; 2 When is 2, 3 or 4, (k 2 +1)valent hydrocarbon group.

[0087] X 6 a hydrocarbyl group having 1 to 40 carbon atoms, a hydrocarbylene group having 1 to 40 carbon atoms, and a (k 2The monovalent hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples of the hydrocarbyl group having 1 to 40 carbon atoms include alkyl groups having 1 to 40 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and icosanyl; cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, and tricyclodecyl. Examples of the hydrocarbylene group include cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms, such as an allyl group, a tetracyclododecanyl group, a tetracyclododecanylmethyl group, and a dicyclohexylmethyl group; unsaturated hydrocarbyl groups having 2 to 40 carbon atoms, such as an allyl group, a 3-cyclohexenyl group, and a tetracyclododecenyl group; aryl groups having 6 to 40 carbon atoms, such as a phenyl group, a 1-naphthyl group, and a 2-naphthyl group; aralkyl groups having 7 to 40 carbon atoms, such as a benzyl group and a diphenylmethyl group; hydrocarbyl groups having 20 to 40 carbon atoms and having a steroid skeleton, which may contain a heteroatom; and groups obtained by combining these. Specific examples of the hydrocarbylene group having 1 to 40 carbon atoms include groups obtained by further removing one hydrogen atom from the specific examples of the hydrocarbyl group described above, and the above-mentioned (k) groups having 1 to 40 carbon atoms are also suitable. 2 Specific examples of the +1)valent hydrocarbon group include those obtained by further adding a hydrogen atom to the specific examples of the hydrocarbyl groups described above. 2 Examples of groups include groups obtained by removing one or more groups.

[0088] In addition, the hydrocarbyl group, hydrocarbylene group, and (k 2 A part or all of the hydrogen atoms of the (+1)-valent hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and the hydrocarbyl group, hydrocarbylene group and (k 2A portion of the -CH2- in the monovalent hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, the group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0089] In formula (B), X 7 is a single bond, an ether bond or an ester bond.

[0090] In formula (B), X 8 is a single bond, an ester bond, an ether bond, an amide bond, a urethane bond, or an alkanediyl group having 1 to 10 carbon atoms, and a part of -CH2- in the alkanediyl group may be substituted with an ester bond, an ether bond, an amide bond, or a urethane bond. 3 Examples of the alkanediyl group having 1 to 10 carbon atoms and represented by the following formula include the same as those exemplified above.

[0091] In formula (B), R 6 ~R 8 are each independently a hydrogen atom, a halogen atom, or a saturated hydrocarbyl group having 1 to 40 carbon atoms, and some or all of the hydrogen atoms of the saturated hydrocarbyl group may be substituted with fluorine atoms or hydroxy groups.

[0092] R 6 ~R 8 The saturated hydrocarbyl group having 1 to 40 carbon atoms represented by the formula (A) may be linear, branched, or cyclic. 1 ~R 3 Examples of the saturated hydrocarbyl group having 1 to 40 carbon atoms and represented by the following formula include the same as those exemplified above.

[0093] In formula (B), R 9 and R 10are each independently a halogen atom, a cyano group, a nitro group, a mercapto group, a sulfo group, a saturated hydrocarbyl group having 1 to 10 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and the saturated hydrocarbyl group and the aralkyl group may contain an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom. 9 or two R's 10 may be bonded to each other to form a ring together with the benzene ring to which they are bonded, and R 9 and R 10 and may be bonded to each other to form a ring together with the benzene ring to which they are bonded and the sulfur atom therebetween. In this case, the ring may be a ring formed by combining two R 4 , two R 5 or R 4 and R 5 and may be bonded to each other to form a ring together with the benzene ring to which they are bonded and the sulfur atom therebetween, and the same rings as those exemplified above may be mentioned.

[0094] In formula (B), Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, and at least one of them is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 may combine to form a carbonyl group.

[0095] k 2 When R is 1 or more, examples of the sulfonate anion having a polymerizable double bond of the sulfonium salt represented by formula (B) include, but are not limited to, those shown below. In the following formula, R is R 6 ~R 8 is the same as the definition of [ka]

[0096] [ka]

[0097]

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[0098]

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[0099]

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[0100]

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[0101]

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[0102]

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[0103]

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[0104]

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[0105]

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[0106]

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[0107]

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[0108] [ka]

[0109] [ka]

[0110] [ka]

[0111] k 2 When is 0, examples of the anion of the sulfonium salt represented by formula (B) that does not have a polymerizable double bond include, but are not limited to, those shown below: In the following formula, Ac is an acetyl group. [ka]

[0112] [ka]

[0113] [ka]

[0114] [ka]

[0115] [ka]

[0116] [ka]

[0117] As the sulfonate anion of the sulfonium salt represented by formula (B), a sulfonate anion containing a benzene ring substituted with an iodine atom represented by the following formula (B-1) is also preferred. [ka]

[0118] In formula (B-1), x is an integer that satisfies 1≦x≦3, and y and z are integers that satisfy 1≦y≦5, 0≦z≦3, and 1≦y+z≦5.

[0119] In formula (B-1), X 11 is a single bond, an ether bond, an ester bond, an amide bond, an imide bond, or a saturated hydrocarbylene group having 1 to 6 carbon atoms, and some of the -CH2- in the saturated hydrocarbylene group may be substituted with an ether bond or an ester bond. The -CH2- in the saturated hydrocarbylene group may be located at its terminal.

[0120] X 11 The saturated hydrocarbylene group having 1 to 6 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include alkanediyl groups having 1 to 6 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, and hexane-1,6-diyl group; cyclic saturated hydrocarbylene groups having 3 to 6 carbon atoms, such as cyclopropanediyl group, cyclobutanediyl group, cyclopentanediyl group, and cyclohexanediyl group; and groups obtained by combining these groups.

[0121] In formula (B-1), X 12 When x is 1, it is a single bond or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom, and when x is 2 or 3, it is an (x+1)-valent hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom.

[0122] X 12The hydrocarbylene group having 1 to 20 carbon atoms represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group, and a dodecane-1,12-diyl group. alkanediyl groups having 1 to 20 carbon atoms; cyclic saturated hydrocarbylene groups having 3 to 20 carbon atoms such as cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, and adamantanediyl group; unsaturated aliphatic hydrocarbylene groups having 2 to 20 carbon atoms such as vinylene group and propene-1,3-diyl group; arylene groups having 6 to 20 carbon atoms such as phenylene group and naphthylene group; and groups obtained by combining these. 12 The (x+1)-valent hydrocarbon group having 1 to 20 carbon atoms, represented by the formula (I), may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include groups obtained by further removing one or two hydrogen atoms from the specific examples of the hydrocarbylene group having 1 to 20 carbon atoms described above.

[0123] X 13 is a single bond, an ether bond or an ester bond.

[0124] In formula (B-1), R 11 is a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms or a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group or an ether bond, or 11A )(R 11B ), -N(R 11C )-C(=O)-R11D or -N(R 11C )-C(=O)-OR 11D R 11A and R 11B are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 11C is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and some or all of the hydrogen atoms of the saturated hydrocarbyl group may be substituted with a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. 11D represents 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 some or all of the hydrogen atoms of these groups may be substituted with a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. When x and / or z is 2 or more, each R 11 may be the same or different from each other.

[0125] R 11The hydrocarbyl moiety of the hydrocarbyl group having 1 to 20 carbon atoms, the hydrocarbyloxy group having 1 to 20 carbon atoms, the hydrocarbylcarbonyl group having 2 to 20 carbon atoms, the hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, the hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, and the hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms, represented by the following formula (I) may be linear, branched, or cyclic, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an ... alkyl groups having 1 to 20 carbon atoms, such as 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 icosyl groups; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, and cyclohexylmethyl groups; C20 saturated cyclic hydrocarbyl groups such as vinyl, propenyl, butenyl, and hexenyl groups; C20 alkenyl groups such as vinyl, propenyl, butenyl, and hexenyl groups; C30 unsaturated cyclic aliphatic hydrocarbyl groups such as cyclohexenyl and norbornenyl groups; C20 alkynyl groups such as ethynyl, propynyl, and butynyl groups; C20 alkynyl groups such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, and n- Examples thereof include aryl groups having 6 to 20 carbon atoms, such as a butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, an n-propylnaphthyl group, an isopropylnaphthyl group, an n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group, and a tert-butylnaphthyl group; aralkyl groups having 7 to 20 carbon atoms, such as a benzyl group and a phenethyl group; and groups obtained by combining these.

[0126] R 11A , R 11B and R 11CThe saturated hydrocarbyl group having 1 to 6 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl groups; and cyclic saturated hydrocarbyl groups having 3 to 6 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups. 11C Examples of the saturated hydrocarbyl moiety of the saturated hydrocarbyloxy group having 1 to 6 carbon atoms that can be contained in R include the same as the specific examples of the saturated hydrocarbyl group described above. 11C Examples of the saturated hydrocarbyl moiety of the saturated hydrocarbyl carbonyl group having 2 to 6 carbon atoms and the saturated hydrocarbyl carbonyloxy group having 2 to 6 carbon atoms that can be contained in include those having 1 to 5 carbon atoms among the specific examples of the saturated hydrocarbyl groups having 1 to 6 carbon atoms mentioned above.

[0127] R 11D The aliphatic hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 16 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, and pentadecyl groups; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, and 4-methyl. Examples of the alkyl group include saturated cyclic hydrocarbyl groups having 3 to 16 carbon atoms, such as cyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 16 carbon atoms, such as vinyl, propenyl, butenyl, and hexenyl; alkynyl groups having 2 to 20 carbon atoms, such as ethynyl, propynyl, and butynyl; unsaturated aliphatic cyclic hydrocarbyl groups having 3 to 16 carbon atoms, such as cyclohexenyl and norbornenyl; and groups obtained by combining these groups. 11D Examples of the aryl group having 6 to 12 carbon atoms represented by R include a phenyl group and a naphthyl group. 11DExamples of the aralkyl group having 7 to 15 carbon atoms represented by the formula R include a benzyl group and a phenethyl group. 11D The hydrocarbyl moiety of the saturated hydrocarbyloxy group having 1 to 6 carbon atoms that can be contained in R 11A , R 11B and R 11C Examples of the saturated hydrocarbyl group having 1 to 6 carbon atoms and represented by the formula (m) include the same as those exemplified above, and examples of the saturated hydrocarbyl moiety of the saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms or the saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms include those having 1 to 5 carbon atoms among the above-mentioned specific examples of the saturated hydrocarbyl group having 1 to 6 carbon atoms.

[0128] In formula (B-1), Rf 11 ~Rf 14 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, and at least one of them is a fluorine atom or a trifluoromethyl group. 11 and Rf 12 may combine to form a carbonyl group. 11 ~Rf 14 The total number of fluorine atoms contained in is preferably 2 or more, more preferably 3 or more.

[0129] Examples of the anion represented by formula (B-1) include, but are not limited to, those shown below. [ka]

[0130] [ka]

[0131] [ka]

[0132] [ka]

[0133]

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[0134]

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[0135]

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[0136]

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[0137]

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[0138]

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[0139]

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[0140]

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[0141]

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[0142]

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[0143]

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[0144]

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[0145]

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[0146]

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[0147]

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[0148]

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[0149]

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[0150]

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[0151]

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[0152]

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[0153]

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[0154]

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[0155]

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[0156]

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[0157]

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[0158]

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[0159]

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[0160]

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[0161]

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[0162]

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[0163]

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[0164]

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[0165] [ka]

[0166] [ka]

[0167] [ka]

[0168] [ka]

[0169] [ka]

[0170] [ka]

[0171] Examples of the sulfonium cation having a polymerizable double bond of the sulfonium salt represented by formula (B) include the same as those exemplified as the sulfonium cation having a polymerizable double bond of the sulfonium salt represented by formula (A).

[0172] The sulfonium salt represented by formula (B) can be synthesized by ion exchange between a fluorosulfonic acid that provides the anion and a sulfonium salt that is a weaker acid than the fluorosulfonic acid and contains the sulfonium cation. Examples of the weak acid include carbonic acid and halogens. Alternatively, the sulfonium salt can be synthesized by ion exchange between a sodium salt or ammonium salt of fluorosulfonic acid that provides the anion and a sulfonium chloride that contains the sulfonium cation.

[0173] In the negative resist material of the present invention, the content of the acid generator consisting of a sulfonium salt represented by Formula (B) is preferably 0.01 to 1,000 parts by mass, and more preferably 0.05 to 500 parts by mass, per 100 parts by mass of the base polymer described below, from the viewpoints of sensitivity and acid diffusion suppression effect.

[0174] [Base polymer] The base polymer contained in the negative resist material of the present invention preferably contains a repeating unit represented by the following formula (a1) (hereinafter also referred to as repeating unit a1). [ka]

[0175] In formula (a1), R A is a hydrogen atom or a methyl group. 1 R is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and containing at least one bond selected from an ester bond, an ether bond, and a lactone ring. 21 is an acid labile group.

[0176] Examples of monomers that provide the repeating unit a1 include, but are not limited to, the following: A and R 21 is the same as above. [ka]

[0177] The base polymer may contain a repeating unit represented by the following formula (a2) (hereinafter also referred to as repeating unit a2). [ka]

[0178] In formula (a2), R A is a hydrogen atom or a methyl group. 2 is a single bond or an ester bond.3 is a single bond, an ether bond, or an ester bond. 22 is an acid labile group. 23 R is a fluorine atom, a trifluoromethyl group, a cyano group, a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 7 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 7 carbon atoms, or a saturated hydrocarbyloxycarbonyl group having 2 to 7 carbon atoms. 24 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of the carbon atoms of which may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer of 0 to 4.

[0179] Examples of the monomer that provides the repeating unit a2 include, but are not limited to, the following: A and R 22 is the same as above. [ka]

[0180] R in the repeating units a1 and a2 21 and R 22 Examples of the acid labile group represented by the formula (I) include those described in JP-A Nos. 2013-80033 and 2013-83821.

[0181] Typical examples of the acid labile group include those represented by the following formulae (AL-1) to (AL-3). [ka] (In the formula, the dashed lines represent bonds.)

[0182] In formulas (AL-1) and (AL-2), R L1 and R L2are each independently a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group is preferably a saturated hydrocarbyl group having 1 to 40 carbon atoms, more preferably a saturated hydrocarbyl group having 1 to 20 carbon atoms.

[0183] In formula (AL-1), c is an integer of 0 to 10, and an integer of 1 to 5 is preferred.

[0184] In formula (AL-2), R L3 and R L4 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group is preferably a saturated hydrocarbyl group having 1 to 20 carbon atoms. In addition, R L2 , R L3 and R L4 Any two of these may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom or the carbon atom and oxygen atom to which they are bonded. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0185] In formula (AL-3), R L5 , R L6 and R L7 are each independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group is preferably a saturated hydrocarbyl group having 1 to 20 carbon atoms. In addition, R L5 , R L6 and R L7 Any two of these may be bonded to each other together with the carbon atoms to which they are bonded to form a ring having 3 to 20 carbon atoms. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0186] The base polymer may further contain a repeating unit b containing a phenolic hydroxy group as an adhesive group. Examples of monomers that provide the repeating unit b include, but are not limited to, the following. In the following formula, R A is the same as above. [ka]

[0187] The base polymer may further contain a repeating unit c containing, as another adhesive group, a hydroxy group other than a phenolic hydroxy group, a lactone ring, a sultone ring, an ether bond, an ester bond, a sulfonate ester bond, a carbonyl group, a sulfonyl group, a cyano group, or a carboxy group. Monomers that provide the repeating unit c include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0188] [ka]

[0189] [ka]

[0190] [ka]

[0191] [ka]

[0192] [ka]

[0193] [ka]

[0194] [ka]

[0195] [ka]

[0196] [ka]

[0197] The base polymer may further include a repeating unit d derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene, or a derivative thereof. Monomers that provide the repeating unit d include, but are not limited to, the following: [ka]

[0198] The base polymer may further include repeat units e derived from styrene, vinylnaphthalene, vinylanthracene, vinylpyrene, methyleneindane, vinylpyridine, or vinylcarbazole.

[0199] The base polymer for the negative resist material for organic solvent development must have a repeating unit a1 containing an acid-labile group. In this case, the content ratios of the repeating units a1, a2, b, c, d, and e are preferably 0 < a1 < 1.0, 0 ≦ a2 < 1.0, 0 < a1 + a2 < 1.0, 0 ≦ b ≦ 0.9, 0 ≦ c ≦ 0.9, 0 ≦ d ≦ 0.8, 0 ≦ e ≦ 0.8, more preferably 0.1 ≦ a1 ≦ 0.9, 0 ≦ a2 ≦ 0.9, 0.1 ≦ a1 + a2 ≦ 0.9, 0 ≦ b ≦ 0.8, 0 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.7, 0 ≦ e ≦ 0.7, and still more preferably 0.2 ≦ a1 ≦ 0.8, 0 ≦ a2 ≦ 0.8, 0.2 ≦ a1 + a2 ≦ 0.8, 0 ≦ b ≦ 0.75, 0 ≦ c ≦ 0.75, 0 ≦ d ≦ 0.6, 0 ≦ e ≦ 0.6. Also, a1 + a2 + b + c + d + e = 1.0.

[0200] To synthesize the base polymer, for example, monomers that provide the above-mentioned repeating units may be heated in an organic solvent with a radical polymerization initiator added to carry out the polymerization.

[0201] 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.

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

[0203] When hydroxystyrene or hydroxyvinylnaphthalene is copolymerized, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and after polymerization, the acetoxy groups may be deprotected by the alkaline hydrolysis to form hydroxystyrene units or hydroxyvinylnaphthalene units.

[0204] The base that can be used in alkaline hydrolysis includes aqueous ammonia, triethylamine, etc. The reaction temperature is preferably −20 to 100° C., more preferably 0 to 60° C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0205] The base polymer preferably has a weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) using THF as a solvent of 1,000 to 500,000, more preferably 2,000 to 30,000. When the Mw is within this range, the resist film has good heat resistance and solubility in organic solvent developers.

[0206] Furthermore, if the base polymer has a broad molecular weight distribution (Mw / Mn), the presence of low-molecular-weight and high-molecular-weight polymers may result in the appearance of foreign matter on the pattern after exposure, or the pattern shape may be deteriorated. As the pattern rule becomes finer, the effects of Mw and Mw / Mn tend to become greater. Therefore, in order to obtain a resist material that is suitable for use with fine pattern dimensions, it is preferable that the Mw / Mn of the base polymer has a narrow distribution of 1.0 to 2.0, particularly 1.0 to 1.5.

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

[0208] [Organic solvents] The negative 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 below. Examples of the organic solvent include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, as described in paragraphs

[0144] and

[0145] of JP-A-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 of the alkyl ester include ethers such as propylene glycol 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 mono-tert-butyl ether acetate; and lactones such as γ-butyrolactone.

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

[0210] [Other ingredients] In addition to the components described above, the negative resist material of the present invention may also contain a quencher other than the sulfonium salt represented by formula (A) (hereinafter also referred to as “other quencher”), an acid generator other than the sulfonium salt represented by formula (B) (hereinafter also referred to as “other acid generator”), a surfactant, a crosslinking agent, a radical generator, a radical scavenger, a water repellency improver, acetylene alcohols, etc.

[0211] Examples of the other quenchers include conventional basic compounds. Examples of conventional basic compounds include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxy group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, and carbamates. Particularly preferred are the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP 2008-111103 A, particularly amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate ester bond, and compounds having a carbamate group described in Japanese Patent No. 3790649 A. Addition of such basic compounds can, for example, further suppress the diffusion rate of acid in the resist film or correct the shape.

[0212] Further, examples of the quencher include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids, carboxylic acids, or fluorinated alkoxides that are not fluorinated at the α-position, as described in JP-A-2008-158339. Sulfonic acids, imide acids, or methide acids that are fluorinated at the α-position are necessary for deprotecting the acid labile group of a carboxylic acid ester, but salt exchange with an onium salt that is not fluorinated at the α-position releases sulfonic acids, carboxylic acids, or fluorinated alcohols that are not fluorinated at the α-position. Sulfonic acids, carboxylic acids, and fluorinated alcohols that are not fluorinated at the α-position do not undergo a deprotection reaction, and therefore function as quenchers.

[0213] Examples of the other acid generator include compounds (photoacid generators) that generate acid in response to actinic rays or radiation. The photoacid generator may be any compound that generates an acid upon exposure to high-energy rays, but is preferably one that generates a sulfonic acid, an imide acid, or a methide acid. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate-type acid generators. Specific examples of acid generators include those described in paragraphs

[0122] to

[0142] of JP 2008-111103 A, JP 2018-5224 A, and JP 2018-25789 A. When the negative resist material of the present invention contains another acid generator, the content thereof is preferably 0 to 200 parts by mass, and more preferably 0.1 to 100 parts by mass, per 100 parts by mass of the base polymer. The other acid generators may be used alone or in combination of two or more.

[0214] Examples of the surfactant include those described in paragraphs

[0165] and

[0166] of JP 2008-111103 A. Adding a surfactant can further improve or control the coatability of the resist material. When the negative resist material of the present invention contains the surfactant, the content thereof 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.

[0215] Adding a crosslinking agent to the negative resist material of the present invention can further reduce the dissolution rate of the exposed area, thereby improving the rectangularity of the negative pattern. Examples of crosslinking agents include epoxy compounds, melamine compounds, guanamine compounds, glycoluril compounds, urea compounds, isocyanate compounds, azide compounds, and compounds containing double bonds, such as alkenyloxy groups, acrylic groups, methacrylic groups, and styryl groups, all substituted with at least one group selected from methylol groups, alkoxymethyl groups, and acyloxymethyl groups. These may be used as additives or may be introduced as pendant groups into polymer side chains. Hydroxy-containing compounds may also be used as crosslinking agents.

[0216] Examples of the epoxy compound include tris(2,3-epoxypropyl)isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether.

[0217] Examples of the melamine compound include hexamethylol melamine, hexamethoxymethyl melamine, a compound in which 1 to 6 methylol groups of hexamethylol melamine are methoxymethylated, or a mixture thereof, hexamethoxyethyl melamine, hexaacyloxymethyl melamine, a compound in which 1 to 6 methylol groups of hexamethylol melamine are acyloxymethylated, or a mixture thereof.

[0218] Examples of the guanamine compound include tetramethylolguanamine, tetramethoxymethylguanamine, a compound in which 1 to 4 methylol groups of tetramethylolguanamine are methoxymethylated, or a mixture thereof; tetramethoxyethylguanamine, tetraacyloxyguanamine, a compound in which 1 to 4 methylol groups of tetramethylolguanamine are acyloxymethylated, or a mixture thereof; and the like.

[0219] Examples of glycoluril compounds include tetramethylol glycoluril, tetramethoxy glycoluril, tetramethoxymethyl glycoluril, compounds in which 1 to 4 methylol groups of tetramethylol glycoluril have been methoxymethylated or mixtures thereof, and compounds in which 1 to 4 methylol groups of tetramethylol glycoluril have been acyloxymethylated or mixtures thereof.

[0220] Examples of the urea compound include tetramethylol urea, tetramethoxymethyl urea, a compound in which 1 to 4 methylol groups of tetramethylol urea are methoxymethylated, or a mixture thereof, and tetramethoxyethyl urea.

[0221] Examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate.

[0222] Examples of the azide compound include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

[0223] Examples of compounds containing an alkenyloxy group include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, and trimethylolpropane trivinyl ether.

[0224] When the negative resist composition of the present invention contains the crosslinking agent, the content thereof is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, per 100 parts by mass of the base polymer. The crosslinking agents may be used alone or in combination of two or more.

[0225] The negative resist material of the present invention may contain a radical generator to increase the reactivity of the double bond in the acid generator. The radical generator is preferably a photoradical generator, and specific examples thereof include acetophenone, 4,4'-dimethoxybenzyl, benzyl, benzoin, benzophenone, 2-benzoylbenzoic acid, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, benzoin isobutyl ether, 4-benzoylbenzoic acid, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, methyl 2-benzoylbenzoate, 2-(1,3-benzodioxol-5-yl)-4,6-bis(trichloromethyl)-1,3,5-trimethylbenzoate, and the like. Examples of suitable acetophenones include riazine, 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, 4,4'-dichlorobenzophenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,4-diethylthioxanthen-9-one, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, 1,4-dibenzoylbenzene, 2-ethylanthraquinone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 2-isonitrosopropiophenone, 2-phenyl-2-(p-toluenesulfonyloxy)acetophenone (BAPO), and camphorquinone.

[0226] When the negative resist composition of the present invention contains the radical generator, the content thereof is preferably 0.1 to 50 parts by mass relative to 100 parts by mass of the base polymer. The radical generator may be used alone or in combination of two or more types.

[0227] The negative resist material of the present invention may contain a radical scavenger to suppress radical diffusion. Examples of the radical scavenger include hindered phenol compounds, quinone compounds, hindered amine compounds, thiol compounds, and TEMPO compounds. Specifically, examples of hindered phenol compounds include dibutylhydroxytoluene (BHT) and 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (ANTAGE W-400). Examples of quinone compounds include 4-methoxyphenol (methoquinone) and hydroquinone. Examples of hindered amine compounds include 2,2,6,6-tetramethylpiperidine. Examples of thiol compounds include dodecanethiol and hexadecanethiol. Examples of TEMPO compounds include 2,2,6,6-tetramethylpiperidine N-oxy radical.

[0228] When the negative resist composition of the present invention contains the radical scavenger, the content thereof is preferably 0 to 5 parts by mass, more preferably 0 to 4 parts by mass, relative to 100 parts by mass of the base polymer. The radical scavenger may be used alone or in combination of two or more types.

[0229] The water repellency improver improves the water repellency of the resist film surface and can be used in immersion lithography without a topcoat. Preferred examples of the water repellency improver include polymers containing fluorinated alkyl groups and polymers containing a specific 1,1,1,3,3,3-hexafluoro-2-propanol residue structure, with those exemplified in JP-A Nos. 2007-297590 and 2008-111103 being more preferred. The water repellency improver must be soluble in an organic solvent developer. The water repellency improver having the specific 1,1,1,3,3,3-hexafluoro-2-propanol residue described above has good solubility in the developer. As a water repellency improver, polymers containing repeating units containing amino groups or amine salts are highly effective in preventing the evaporation of acid during PEB and preventing poor opening of hole patterns after development. When the negative resist composition of the present invention contains a water repellency improver, the content thereof is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 100 parts by mass of the base polymer. The water repellency improver may be used alone or in combination of two or more.

[0230] Examples of the acetylene alcohols include those described in paragraphs

[0179] to

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

[0231] [Pattern formation method] When the negative 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 can include a method comprising the steps of forming a resist film on a substrate using the negative resist material, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer.

[0232] First, the negative resist material of the present invention is applied to a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflective coating, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., to a coating thickness of 0.01 to 2 μm. This is then prebaked on a hot plate, preferably at 60 to 150°C for 10 seconds to 30 minutes, more preferably at 80 to 120°C for 30 seconds to 20 minutes, to form a resist film.

[0233] Next, the resist film is exposed to high-energy radiation. Examples of the high-energy radiation include ultraviolet radiation, far ultraviolet radiation, EB, EUV radiation with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation. When ultraviolet radiation, far ultraviolet radiation, EUV radiation, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation are used as the high-energy radiation, the exposure dose is preferably 1 to 200 mJ / cm, either directly or using a mask for forming a desired pattern. 2 approximately, more preferably 10 to 100 mJ / cm 2 When EB is used as the high energy beam, the exposure dose is preferably 0.1 to 500 μC / cm 2 approximately, more preferably 0.5 to 400 μC / cm 2 The negative resist material of the present invention is particularly suitable for fine patterning using high-energy rays such as KrF excimer laser light, ArF excimer laser light, EB, EUV, X-rays, soft X-rays, γ-rays, and synchrotron radiation, and is particularly suitable for fine patterning using EB or EUV.

[0234] During exposure to high-energy radiation, the double bond of the quencher represented by formula (A) in the exposed portion of the resist film polymerizes, causing a crosslinking reaction. Furthermore, when the acid generator is represented by formula (B), the double bond contained therein also polymerizes, causing a crosslinking reaction. As the crosslinking reaction progresses, the remaining film in the exposed portion increases, improving dissolution contrast and increasing the mechanical strength of the film in the exposed portion, making pattern collapse less likely to occur.

[0235] After exposure, PEB may or may not be performed on a hot plate or in an oven, preferably at 30 to 150° C. for 10 seconds to 30 minutes, more preferably at 50 to 120° C. for 30 seconds to 20 minutes.

[0236] A negative pattern is then obtained by organic solvent development. Developers used in this process include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, isopentyl acetate, 2-methylbutyl acetate, hexyl acetate, butenyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, Examples of the organic solvent include ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents may be used alone or in combination of two or more.

[0237] After the development is completed, the resist film is rinsed. A solvent that is miscible with the developer but does not dissolve the resist film is preferred as the rinse solution. Preferred examples of such solvents include alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents having 6 to 12 carbon atoms.

[0238] Specific examples of alcohols having 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, and 3-hexanol. , 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol, and the like.

[0239] Examples of the ether compound having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, and di-n-hexyl ether.

[0240] Examples of alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, etc. Examples of alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Examples of alkynes having 6 to 12 carbon atoms include hexyne, heptine, octyne, etc.

[0241] Examples of aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0242] Rinsing can reduce the occurrence of resist pattern collapse and defects. Rinsing is not always necessary, and not performing rinsing can reduce the amount of solvent used.

[0243] The developed hole pattern or trench pattern can also be shrunk by thermal flow, RELACS technology, or DSA technology. A shrink agent is applied to the hole pattern, and the diffusion of an acid catalyst from the resist film during baking causes crosslinking of the shrink agent on the surface of the resist film, resulting in the shrink agent adhering to the sidewalls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds. Excess shrink agent is removed. Removal This reduces the hole pattern. [Example]

[0244] The present invention will be specifically explained below by showing synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples.

[0245] The structures of the sulfonium salt quenchers Q-1 to Q-19 used in the resist materials are shown below. [ka]

[0246] [ka]

[0247] [ka]

[0248] [Synthesis Example 1-1] Synthesis of Quencher Q-1 (1) Synthesis of Compound 2 [ka]

[0249] Compound 1 (50 g), triethylamine (28.2 g), 4-dimethylaminopyridine (DMAP) (3.1 g), acetonitrile (450 g), and 2,6-di-tert-butylphenol (1000 ppm / theoretical yield) as a polymerization inhibitor were dissolved in the solution. Methacrylic anhydride (47.1 g) was added dropwise under ice cooling, and the mixture was stirred at room temperature for 14 hours. After the reaction was completed, the mixture was cooled on ice, and 5% by weight aqueous sodium bicarbonate solution (100 g) was added and stirred for 1 hour. The organic layer was separated and subjected to standard aqueous work-up. The solvent was evaporated, and hexane (500 g) was added and washed with stirring for 2 hours. The solvent was then removed, yielding compound 2 as an oil (yield 58.1 g).

[0250] (2) Synthesis of Compound 3 [ka]

[0251] Compound 2 (58 g) was dissolved in a mixed solvent of dioxane (400 g) and purified water (100 g). A 25% by weight aqueous solution of tetramethylammonium hydroxide (TMAH) (80.0 g) was added dropwise at room temperature, followed by stirring for 14 hours. After completion of the reaction, dioxane was distilled off, and benzyltrimethylammonium chloride (48.9 g) and methylene chloride (400 g) were added and stirred for 1 hour. The organic layer was separated and subjected to standard aqueous work-up. The solvent was distilled off, hexane (500 g) was added, and the mixture was stirred for 2 hours. The mixture was then filtered to obtain compound 3 as a white solid (yield 74.4 g).

[0252] (3) Synthesis of quencher Q-1 [ka]

[0253] Compound 3 (20.0 g), compound 4 (21.9 g), methylene chloride (200 g), and purified water (50 g) were placed in a flask and stirred for 1 hour. The organic layer was separated and subjected to standard aqueous work-up. The solvent was evaporated, and hexane (150 g) was added. The mixture was stirred for 1 hour and then filtered to obtain quencher Q-1 as a white solid (yield 29.0 g).

[0254] [Synthesis Example 1-2] Synthesis of Quencher Q-2 [ka]

[0255] Compound 3 (20.0 g), compound 5 (31.5 g), methylene chloride (200 g), and purified water (100 g) were added to a flask and stirred for 1 hour. The organic layer was separated and subjected to standard aqueous work-up. The solvent was evaporated, and hexane (200 g) was added. The mixture was stirred for 1 hour and then filtered to obtain quencher Q-2 as a white solid (yield 34.2 g).

[0256] [Synthesis Example 1-3] Synthesis of Quencher Q-3 [ka]

[0257] Compound 3 (20.0 g), compound 6 (23.5 g), methylene chloride (200 g), and purified water (100 g) were placed in a flask and stirred for 1 hour. The organic layer was separated and subjected to standard aqueous work-up. The solvent was evaporated, and hexane (150 g) was added. The mixture was stirred for 1 hour and then filtered to obtain quencher Q-3 as a white solid (yield 30.1 g).

[0258] [Synthesis Example 1-4] Synthesis of Quencher Q-4 (1) Synthesis of Compound 7 [ka]

[0259] Compound 1 (39.7 g), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (WSC·HCl) (45.3 g), DMAP (4.1 g), and methyl isobutyl ketone (MIBK) (400 g) were placed in a stirred flask, and a solution of 4-4-vinylbenzoic acid (25.0 g) in THF (100 g) was added dropwise. After the dropwise addition, triethylamine (3.4 g) was added and the mixture was stirred at room temperature for 24 hours. After stirring, 1% by weight aqueous hydrochloric acid (100 g) was added under ice cooling to quench the reaction. MIBK (300 g) was added and the mixture was stirred at room temperature. The organic layer was separated and subjected to standard aqueous work-up. The solvent was evaporated, and diisopropyl ether (400 g) was added. The mixture was stirred for 1 hour and then filtered to obtain compound 7 as a white solid (yield 45.2 g).

[0260] (2) Synthesis of Compound 8 [ka]

[0261] Compound 7 (45.0 g) was dissolved in a mixed solvent of dioxane (400 g) and purified water (100 g). 25% by weight TMAH aqueous solution (50.5 g) was added dropwise at room temperature, followed by stirring for 14 hours. After completion of the reaction, dioxane was distilled off, and benzyltrimethylammonium chloride (30.7 g) and methylene chloride (500 g) were added and stirred for 1 hour. The organic layer was separated and subjected to standard aqueous work-up. The solvent was distilled off, and diisopropyl ether (100 g) was added. The mixture was stirred for 2 hours and then filtered to obtain compound 8 as a white solid (yield 58.7 g).

[0262] (3) Synthesis of quencher Q-4 [ka]

[0263] Compound 8 (20.0 g), compound 4 (18.8 g), methylene chloride (200 g), and purified water (100 g) were added to a flask and stirred for 1 hour. The organic layer was separated and subjected to standard aqueous work-up. The solvent was evaporated, and hexane (250 g) was added. The mixture was stirred for 1 hour and then filtered to obtain quencher Q-4 as a white solid (yield 26.5 g).

[0264] [Synthesis Example 1-5] Synthesis of Quencher Q-5 [ka]

[0265] Compound 8 (20.0 g), compound 9 (25.0 g), methylene chloride (200 g), and purified water (100 g) were added to a flask and stirred for 1 hour. The organic layer was separated and subjected to standard aqueous work-up. The solvent was evaporated, and hexane (250 g) was added. The mixture was stirred for 1 hour and then filtered to obtain quencher Q-5 as a white solid (yield 32.3 g).

[0266] [Synthesis Examples 1-6 to 1-19] Synthesis of Quenchers Q-6 to Q-19 As in Synthesis Examples 1-1 to 1-5, each compound was synthesized by ion exchange between an ammonium salt of sulfonic acid, carboxylic acid, sulfonamide, or alkoxide, which provides the anion, and a sulfonium chloride, which provides the cation.

[0267] [Synthesis Examples 2-1 to 2-4] Synthesis of base polymers (polymers P-1 to P-4) Each monomer was combined and copolymerized in THF solvent, then added to methanol. The precipitated solid was washed with hexane, isolated, and dried to obtain the base polymers (polymers P-1 to P-4) with the following compositions. The resulting base polymers were 1 Mw and Mw / Mn were confirmed by H-NMR and GPC (solvent: THF, standard: polystyrene). [ka]

[0268] [Examples 1 to 23, Comparative Examples 1 and 2] Preparation and Evaluation of Negative Resist Materials (1) Preparation of negative resist material A negative resist material was prepared by dissolving each component in the composition shown in Table 1 in a solvent containing 100 ppm of Omnova's Polyfox PF-636 surfactant. The solution was then filtered through a 0.2 μm filter.

[0269] In Table 1, the components are as follows: Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) PGME (Propylene Glycol Monomethyl Ether) EL (Ethyl lactate) DAA (diacetone alcohol)

[0270] Acid generator: PAG-1 to PAG-8 [ka]

[0271] [ka]

[0272] Comparison quenchers: cQ-1, cQ-2 [ka]

[0273] Radical scavengers: RC-1, RC-2 [ka]

[0274] (2) EB lithography evaluation Nissan Chemical Co., Ltd.'s DUV-42 was applied to a silicon substrate and baked at 200°C for 60 seconds to form an anti-reflective film (60 nm thick). Each negative resist material listed in Table 1 was spin-coated onto the anti-reflective film and pre-baked at 105°C for 60 seconds using a hot plate to produce a 35 nm thick resist film. This was then patterned using an Elionix ELS-F125 EB lithography system at an acceleration voltage of 125 kV and a current of 50 pA. Post-exposure bake (PEB) was performed on the hot plate at the temperature listed in Table 1 for 60 seconds, followed by development with 2-methylbutyl acetate for 30 seconds, yielding a 30 nm line-and-space 1:1 pattern. The formed pattern was observed using a critical dimension SEM (CG5000) manufactured by Hitachi High-Technologies Corporation. The exposure dose required to obtain a 30 nm line-and-space 1:1 pattern was defined as the sensitivity, and the minimum line width (nm) of the separated line-and-space pattern at that exposure dose was determined and used as the limiting resolution. The results are shown in Table 1.

[0275] [Table 1]

[0276] The results shown in Table 1 demonstrate that the negative resist material of the present invention, which contains a specific sulfonium salt having two or more polymerizable double bonds in the molecule as a quencher, has excellent limiting resolution.

Claims

1. A negative resist material comprising: a base polymer; a quencher comprising a sulfonium salt having two or more polymerizable double bonds in the molecule and having a weaker acid than sulfonic acid, the quencher being a fluorinated carbon atom at the α- and / or β-position of a sulfo group; and an acid generator that generates sulfonic acid having a fluorinated carbon atom at the α- and / or β-position of a sulfo group, A negative resist material comprising a quencher composed of a sulfonium salt of an acid weaker than sulfonic acid, which has two or more polymerizable double bonds in the molecule and in which the carbon atoms at the α- and / or β-positions of the sulfo group are fluorinated, and which is represented by any of the following formulas Q-1 to Q-19: 【Chemistry 1】 【Chemistry 2】 【Transformation 3】

2. A negative resist material comprising a base polymer, a quencher consisting of a sulfonium salt having two or more polymerizable double bonds in the molecule and having a weaker acid than sulfonic acid in which the carbon atoms at the α- and / or β-positions of the sulfo group are fluorinated, and an acid generator which is a sulfonium salt that generates sulfonic acid having two or more polymerizable double bonds in the molecule and having a carbon atom at the α- and / or β-positions of the sulfo group fluorinated, A negative resist material, wherein the sulfonium salt of a weaker acid than sulfonic acid, which has two or more polymerizable double bonds in the molecule and in which the carbon atom at the α-position and / or the β-position of the sulfo group is fluorinated, is represented by the following formula (A) or Q-7: 【Chemistry 4】 (In the formula, k 1 , m 1 and n 1 are integers that satisfy 0≦k 1 ≦4, 1≦m 1 ≦3, 0≦n 1 ≦2, 2≦k 1 +m 1 ≦7 and m 1 +n 1 =3. p 1 is 1 or 2, and q 1 is an integer of 0 to 4, with the proviso that 1≦p 1 +q 1 ≦5. r 1 is 0.) X − is —SO 3 − , —CO 2 − , —N − —SO 2 —R F or —O − , where R F is a fluorine atom or a fluorinated hydrocarbyl group having 1 to 10 carbon atoms. X 1 is a single bond or an ester bond. X 2 is a hydrocarbyl group of 1 to 20 carbon atoms which may contain a fluorine atom or a heteroatom when k 1 is 0 and X − is —CO 2 —; a hydrocarbyl group of 1 to 20 carbon atoms which may contain a hydrogen atom or a heteroatom when k 1 is 0 and X − is —N —SO 2 —R F; a hydrocarbyl group of 1 to 20 carbon atoms which may contain a heteroatom when k 1 is 0 and X − is —SO 3 — or —O —; a single bond or a hydrocarbylene group of 1 to 20 carbon atoms which may contain a heteroatom when k 1 is 1; and a (k 1 + 1)-valent hydrocarbon group of 1 to 20 carbon atoms which may contain a heteroatom when k 1 is 2, 3 or 4. However, when X − is —SO 3 − , X 2 does not mean that the carbon atoms at the α- and β-positions of —SO 3 − are fluorinated, and when X − is —O − , the carbon atom to which —O − is bonded is not a carbon atom on an aromatic ring. X 3 is an ester bond. R 1 to R 3 are each independently a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, and some or all of the hydrogen atoms of the methyl or ethyl group may be substituted with fluorine atoms or hydroxy groups. R 4 and R 5 are each independently a saturated hydrocarbyl group having 1 to 10 carbon atoms. 【Transformation 5】

3. 3. The negative resist material according to claim 2, wherein the acid generator, a sulfonium salt having two or more polymerizable double bonds in the molecule, is represented by the following formula (B): 【Transformation 6】 (In the formula, k 2 , m 2 and n 2 is 0≦k 2 ≦4, 1≦m 2 ≦3, 0≦n 2 ≦2, 2≦k 2 +m 2 ≦7 and m 2 +n 2 = 3. 2 is 1 or 2, and q 2 is an integer from 0 to 4, provided that 1≦p 2 +q 2 ≦5. 2 is 0. X 5 is a single bond, an ester bond, an ether bond, an amide bond or a urethane bond. X 6 is k 2 When k is 0, it is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom; 2 When k is 1, it is a single bond or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom; 2 When k is 2, 3 or 4, it is a group having 1 to 40 carbon atoms which may contain a heteroatom. 2 +1)valent hydrocarbon group. X 7 is a single bond, an ether bond or an ester bond. X 8 is an ester bond. R 6 ~R 8 are each independently a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, and some or all of the hydrogen atoms of the methyl group or ethyl group may be substituted with a fluorine atom or a hydroxy group. R 9 and R 10 are each independently a saturated hydrocarbyl group having 1 to 10 carbon atoms. Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, and at least one of them is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 may combine to form a carbonyl group.)

4. 4. The negative resist material according to claim 3, wherein the sulfonate anion of the sulfonium salt represented by formula (B) is a sulfonate anion containing a benzene ring substituted with an iodine atom, represented by the following formula (B-1): 【Transformation 7】 In the formula, x is an integer that satisfies 1≦x≦3, and y and z are integers that satisfy 1≦y≦5, 0≦z≦3, and 1≦y+z≦5. X 11 represents a single bond, an ether bond, an ester bond, an amide bond, an imide bond, or a saturated hydrocarbylene group having 1 to 6 carbon atoms, and —CH 2 A part of the - may be substituted with an ether bond or an ester bond. 2 The - may be located at the end. X 12 represents a single bond or a hydrocarbylene group having 1 to 10 carbon atoms which may contain a heteroatom when x is 1, and represents an (x+1)-valent hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom when x is 2 or 3. X 13 is a single bond, an ether bond or an ester bond. R 11 is a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom, or an amino group, or a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, or a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms, which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group, or an ether bond, or 11A )(R 11B ), -N(R 11C )-C(=O)-R 11D Or -N(R 11C )-C(=O)-O-R 11D It is. 11A and R 11B are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 11C is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and some or all of the hydrogen atoms of the saturated hydrocarbyl group may be substituted with a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. 11D represents 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 some or all of the hydrogen atoms of these groups may be substituted with a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. When x and / or z is 2 or more, each R 11 may be the same or different from each other. Rf 11 ~Rf 14 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, and at least one of them is a fluorine atom or a trifluoromethyl group. 11 and Rf 12 may combine to form a carbonyl group.

5. 3. The negative resist material according to claim 2, wherein the acid generator is any one of PAG-1 to PAG-15 below. 【Transformation 8】 【Chemistry 9】

6. 2. The negative resist material according to claim 1, wherein the base polymer contains a repeating unit represented by the following formula (a1): 【Chemistry 10】 (In the formula, R A are each independently a hydrogen atom or a methyl group. Y 1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and containing at least one bond selected from an ester bond, an ether bond, and a lactone ring. R 21 is an acid labile group.

7. 2. The negative resist material according to claim 1, further comprising an organic solvent.

8. 2. The negative resist material according to claim 1, further comprising a crosslinking agent.

9. 2. The negative 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 the negative resist material according to any one of claims 1 to 9; exposing the negative resist film to high-energy rays; and developing the exposed negative resist film using an organic solvent developer.

11. The organic solvent developer may be selected from the group consisting of 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, isopentyl acetate, 2-methylbutyl acetate, hexyl acetate, butenyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, propionate, 11. The pattern formation method according to claim 10, wherein the lactone is at least one selected from the group consisting of methyl lactate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, and 2-phenylethyl acetate.

12. 11. The pattern forming method according to claim 10, wherein the high-energy beam is a KrF excimer laser beam, an ArF excimer laser beam, an electron beam, or extreme ultraviolet light having a wavelength of 3 to 15 nm.

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