Molecular resist composition and pattern forming method

Abstract

The present invention provides a molecular resist composition that is excellent in sensitivity, resolution, and LWR in photolithography using high-energy rays, and a pattern formation method that uses the molecular resist composition. [Solution] A molecular resist composition comprising a sulfonium salt represented by the following formula (1) or (2), an iodonium salt containing an iodonium cation represented by the following formula (1-1) and a halide ion, a nitrate ion, a hydrogen sulfate ion, a hydrogen carbonate ion, a tetraphenylborate ion or an anion represented by a specific structure, and an organic solvent, but not containing a base polymer. TIFF2026035103000091.tif23166 TIFF2026035103000092.tif18153

Description

[Technical Field]

[0001] The present invention relates to a molecular resist composition and a patterning method. [Background technology]

[0002] As the IoT market expands, there is a growing demand for higher integration, higher speeds, and lower power consumption in LSIs, leading to rapid progress in miniaturization of pattern rules. Logic devices, in particular, are driving this miniaturization. The most advanced miniaturization technology is ArF immersion lithography, with double patterning, triple patterning, and quadruple patterning being used to mass-produce 10nm-node devices, and studies are underway to develop 7nm-node devices using next-generation extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm.

[0003] Chemically amplified resist compositions can be used in EUV lithography, enabling the formation of line patterns with widths of 20 nm or less. However, when polymeric resist compositions used in ArF lithography are used in EUV lithography, the large molecular size of the base polymer contained in the composition causes roughness on the pattern surface, making pattern control difficult. Therefore, various low-molecular-weight materials have been proposed.

[0004] Molecular resist compositions are primarily composed of low-molecular-weight compounds and do not contain the base polymers typically found in polymeric resist compositions. Molecular resist compositions are expected to be an effective solution for forming fine patterns. For example, a negative-tone radiation-sensitive composition for alkaline development using a polyhydric polyphenol compound as the primary component has been proposed (Patent Document 1). Another positive-tone resist composition for alkaline development has been proposed, containing only an acid generator consisting of a sulfonium salt cation with a tert-butoxycarbonyloxy group attached and a strong acid anion (Non-Patent Document 1). Because the acid generator has a smaller molecular size than polymeric materials, it is expected to improve surface roughness. However, molecular resist compositions using the chemical amplification mechanism have yet to achieve satisfactory performance due to the difficulty in controlling acid diffusion. Furthermore, EUV resist compositions must simultaneously achieve not only low surface roughness but also high sensitivity and high resolution, and further improvements are needed.

[0005] One of the challenges in developing materials for EUV lithography is the low photon count in EUV exposure. EUV energy is much higher than that of ArF excimer laser light, and the photon count in EUV exposure is 1 / 14 that of ArF exposure. Furthermore, the pattern dimensions formed with EUV exposure are less than half that of ArF exposure. This makes EUV exposure susceptible to variations in photon count. The variations in photon count in the extremely short wavelength radiation region are a physical phenomenon known as shot noise, and this effect cannot be eliminated. Therefore, so-called stochastics has attracted attention. While the effects of shot noise cannot be eliminated, methods for reducing this effect are being discussed. Shot noise not only increases dimensional uniformity (CDU) and line width roughness (LWR), but also causes hole blockage with a probability of one in several million. Blocked holes result in poor electrical conductivity, preventing transistor operation and adversely affecting overall device performance.

[0006] As a method for reducing the effects of shot noise on the resist side, inorganic resist compositions containing elements with high EUV absorption have been proposed (Patent Document 2). However, although inorganic resist compositions have relatively high sensitivity, they are still not sufficient and have many issues, such as insufficient solubility in resist solvents, storage stability, and defects. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-326838 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-108781 [Non-patent literature]

[0008] [Non-Patent Document 1] Proc. of SPIE Vol. 6923, 69230K (2008) Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a molecular resist composition that is excellent in sensitivity, resolution, and LWR in photolithography using high-energy rays, and a pattern formation method that uses the molecular resist composition. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides a molecular resist composition comprising a sulfonium salt represented by the following formula (1) or (2), an iodonium salt containing an iodonium cation represented by the following formula (1-1) and a halide ion, a nitrate ion, a hydrogen sulfate ion, a hydrogen carbonate ion, a tetraphenylborate ion, or an anion represented by any of the following formulas (1-2) to (1-8), and an organic solvent, but not containing a base polymer. [ka] (wherein n is an integer of 1 to 3. A 1 A is a hydrocarbyl group having 2 to 20 carbon atoms and containing a polymerizable functional group, and the hydrocarbyl group may contain a heteroatom. 2 contains a polymerizable functional group, and Ar 1B It is a group that forms an alicyclic ring having 4 to 20 carbon atoms together with the two carbon atoms therein, and the alicyclic ring may contain a heteroatom. 1A is an arylene group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the arylene group may be substituted with a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 1B is a trivalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the trivalent aromatic hydrocarbon group may be substituted with a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 2 is an aryl group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the aryl group may be substituted with a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 1A , two Ar 1B , two Ar 2 , Ar 1A and Ar 2 and, or Ar 1B and Ar 2 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. - is the counter anion.) [ka] (In the formula, R 31 , R 32 are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. [ka] (In the formula, k1 and k2 are each independently 1, 2, 3, or 4. Rf 1 and Rf 2 are each independently a hydrogen atom, a fluorine atom, or a fluorine-containing alkyl group having 1 to 6 carbon atoms, but all of Rf 1 and Rf 2 R cannot be a hydrogen atom at the same time. 41 R is a hydrogen atom, a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 42 R is a hydrocarbyl group having 1 to 50 carbon atoms which may contain a hydrogen atom, a halogen atom, a hydroxy group, or a heteroatom, provided that this does not include those in which the hydrogen atoms on the carbon atoms at the α- and β-positions of the sulfo group are substituted with a fluorine atom or a fluoroalkyl group. 51 R is a hydrogen atom, a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 52 R is a hydrocarbyl group having 1 to 50 carbon atoms which may contain a hydrogen atom, a halogen atom, a hydroxy group, or a heteroatom, provided that this does not include those in which the hydrogen atoms on the carbon atoms at the α- and β-positions of the carboxy group are substituted with a fluorine atom or a fluoroalkyl group. 61 and R 62 R are each independently a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 71 ~R 73 R are each independently a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 81 R is a fluorine atom or a fluorinated hydrocarbyl group having 1 to 10 carbon atoms, and the fluorinated hydrocarbyl group may contain a hydroxy group, an ether bond, or an ester bond. 82 is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain a hydroxy group, an ether bond, or an ester bond. 81 and R 82 may be bonded to each other to form a ring together with the atoms to which they are attached.

[0011] Such a molecular resist composition of the present invention is excellent in sensitivity, resolution, and LWR in photolithography using high-energy rays, particularly in electron beam (EB) lithography and EUV lithography.

[0012] In the present invention, the A 1 is an acryloyloxy group, a methacryloyloxy group, a cycloalkenyl group having 3 to 20 carbon atoms which may contain a heteroatom, a cycloalkenyloxy group having 3 to 20 carbon atoms which may contain a heteroatom, a cycloalkenylcarbonyloxy group having 3 to 20 carbon atoms which may contain a heteroatom, an alkenyl group having 2 to 20 carbon atoms which may contain a heteroatom, or an alkenyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, 2 But, Ar 1B It is preferably a group which, together with the two carbon atoms therein, forms a cycloalkene ring having 4 to 20 carbon atoms which may contain a heteroatom, or a polycycle having 4 to 20 carbon atoms and one double bond which may contain a heteroatom.

[0013] A is a hydrocarbyl group containing such a polymerizable functional group. 1 and Ar 1B A is a polymerizable functional group-containing group that forms a ring together with the two carbon atoms in 2 If so, it becomes possible to form a suitable pattern by utilizing polymerization due to the polymerizable functional group.

[0014] In the present invention, the above X - is preferably the same as the counter anion of the iodonium cation represented by the formula (1-1).

[0015] In this way, in the molecular resist composition of the present invention, the anion X of the sulfonium salt represented by the above formula (1) or (2) - and the counter anion of the iodonium cation represented by the above formula (1-1) preferably have the same structure.

[0016] In the present invention, the anion represented by any one of the above formulas (1-2) to (1-8) preferably contains a polymerizable functional group.

[0017] In the present invention, from the viewpoint of pattern formation, it is preferable that both the cation forming the sulfonium salt represented by formula (1) or (2) and the anion represented by any one of formulas (1-2) to (1-8), i.e., the counter anion of the iodonium cation represented by formula (1-1), have a polymerizable functional group, and it is more preferable that both the anion of the sulfonium salt and the anion of the iodonium salt have a polymerizable functional group.

[0018] The molecular resist composition of the present invention may further contain a radical scavenger or a surfactant.

[0019] The molecular resist composition of the present invention can contain such components as needed.

[0020] The present invention also provides a pattern formation method comprising the steps of forming a resist film on a substrate using the molecular resist composition, exposing the resist film to high-energy rays, and developing the exposed resist film using a developer.

[0021] According to the pattern forming method of the present invention, by forming a resist film on a substrate using the molecular resist composition of the present invention, it is possible to form a pattern with excellent sensitivity, resolution, and LWR in photolithography using high-energy rays, particularly in electron beam (EB) lithography and EUV lithography.

[0022] In this case, not only can an alkaline aqueous solution be used as the developer to dissolve the exposed areas and obtain a positive pattern in which the unexposed areas are insoluble, but also an organic solvent or an alkaline aqueous solution can be used as the developer to dissolve the unexposed areas and obtain a negative pattern in which the exposed areas are insoluble.

[0023] Thus, by using the molecular resist composition of the present invention, both positive and negative patterns can be obtained by combining it with an appropriate developer.

[0024] In the present invention, examples of the organic solvent for the developer include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, cyclohexyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, and propyl methyl valerate. It is preferable to use at least one selected from methyl pionate, 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, ethyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, and 2-phenylethyl acetate.

[0025] When a negative pattern is obtained by organic solvent development using the molecular resist composition of the present invention, the above-mentioned organic solvents can be suitably used.

[0026] In the present invention, the high energy beam may be an electron beam or extreme ultraviolet light.

[0027] The molecular resist composition of the present invention is excellent in sensitivity, resolution and LWR, particularly in EB lithography and EUV lithography, and is therefore capable of forming good patterns that meet the demand for finer pattern rules. [Effects of the Invention]

[0028] As described above, the molecular resist composition of the present invention is extremely useful for forming fine patterns in photolithography using high-energy rays, particularly in EB lithography and EUV lithography, because it combines high sensitivity and high resolution and has excellent LWR. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a 1H-NMR spectrum of PAG-1 obtained in Synthesis Example 1-1. [Figure 2] 1 is a 1H-NMR spectrum of PAG-2 obtained in Synthesis Example 1-2. [Figure 3] 1 is a 1H-NMR spectrum of PAG-3 obtained in Synthesis Example 1-3. [Figure 4] 1 is a 1H-NMR spectrum of PAG-4 obtained in Synthesis Example 1-4. [Figure 5] 1 is a 1H-NMR spectrum of PAG-5 obtained in Synthesis Example 1-5. [Figure 6] 1 is a 1H-NMR spectrum of PAG-6 obtained in Synthesis Example 1-6. [Figure 7] 1 is a 1H-NMR spectrum of PAG-7 obtained in Synthesis Example 1-7. [Figure 8] 1 is a 1H-NMR spectrum of PAG-8 obtained in Synthesis Example 1-8. [Figure 9] 1 is a 1H-NMR spectrum of PAG-9 obtained in Synthesis Example 1-9. DETAILED DESCRIPTION OF THE INVENTION

[0030] As a result of extensive research into achieving the above-mentioned object, the present inventors discovered that a molecular resist composition containing a sulfonium salt and an iodonium salt having a specific partial structure provides a resist film that exhibits high sensitivity, excellent resolution and LWR, and is extremely effective for precise microfabrication, which led to the completion of the present invention.

[0031] That is, the present invention provides a molecular resist composition comprising a sulfonium salt represented by the following formula (1) or (2), an iodonium salt containing an iodonium cation represented by the following formula (1-1) and a halide ion, a nitrate ion, a hydrogen sulfate ion, a hydrogen carbonate ion, a tetraphenylborate ion, or an anion represented by any of the following formulas (1-2) to (1-8), and an organic solvent, but not containing a base polymer. [ka] (wherein n is an integer of 1 to 3. A 1 A is a hydrocarbyl group having 2 to 20 carbon atoms and containing a polymerizable functional group, and the hydrocarbyl group may contain a heteroatom. 2 contains a polymerizable functional group, and Ar 1B It is a group that forms an alicyclic ring having 4 to 20 carbon atoms together with the two carbon atoms therein, and the alicyclic ring may contain a heteroatom. 1A is an arylene group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the arylene group may be substituted with a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 1B is a trivalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the trivalent aromatic hydrocarbon group may be substituted with a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 2 is an aryl group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the aryl group may be substituted with a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 1A , two Ar 1B , two Ar 2 , Ar 1A and Ar 2 and, or Ar 1B and Ar 2 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. - is the counter anion.) [ka] (In the formula, R 31 , R 32 are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. [ka] (In the formula, k1 and k2 are each independently 1, 2, 3, or 4. Rf 1 and Rf 2 are each independently a hydrogen atom, a fluorine atom, or a fluorine-containing alkyl group having 1 to 6 carbon atoms, but all of Rf 1 and Rf 2 R cannot be a hydrogen atom at the same time. 41 R is a hydrogen atom, a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 42 R is a hydrocarbyl group having 1 to 50 carbon atoms which may contain a hydrogen atom, a halogen atom, a hydroxy group, or a heteroatom, provided that this does not include those in which the hydrogen atoms on the carbon atoms at the α- and β-positions of the sulfo group are substituted with a fluorine atom or a fluoroalkyl group. 51 R is a hydrogen atom, a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 52 R is a hydrocarbyl group having 1 to 50 carbon atoms which may contain a hydrogen atom, a halogen atom, a hydroxy group, or a heteroatom, provided that this does not include those in which the hydrogen atoms on the carbon atoms at the α- and β-positions of the carboxy group are substituted with a fluorine atom or a fluoroalkyl group. 61 and R 62 R are each independently a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 71 ~R 73 R are each independently a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 81R is a fluorine atom or a fluorinated hydrocarbyl group having 1 to 10 carbon atoms, and the fluorinated hydrocarbyl group may contain a hydroxy group, an ether bond, or an ester bond. 82 is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain a hydroxy group, an ether bond, or an ester bond. 81 and R 82 may be bonded to each other to form a ring together with the atoms to which they are attached.

[0032] The present invention will be described in detail below, but the present invention is not limited thereto. In this specification, the descriptions using the endpoints of numerical ranges include all values ​​included in the range.

[0033] [Molecular Resist] The molecular resist composition of the present invention comprises (i) a sulfonium salt represented by the above formula (1) or (2), (ii) an iodonium cation represented by the above formula (1-1), a halide ion, a nitrate ion (NO3 - ), hydrogen sulfate ion (HSO4 - ), bicarbonate ion (HCO3 - ), tetraphenylborate ion (BPh4 - (iii) an iodonium salt containing an anion represented by any one of the following formulas (1-2) to (1-8), and (iv) an organic solvent, and does not contain a base polymer. In the molecular resist composition of the present invention, the main component means the component other than the solvent that is contained in the largest amount.

[0034] The molecular resist composition of the present invention contains the sulfonium salt, which is a monomolecular compound, as a main component, and by combining this with the photodegradable iodonium salt, the sulfonium salt, which has a polymerizable functional group, is polymerized, and the molecular weight is efficiently increased, even without including a base polymer used in polymer-based resist compositions, making it possible to form patterns with improved contrast, sensitivity, resolution, etc. The sulfonium salts contribute to improving roughness because of their smaller molecular size compared to polymeric materials, while the addition of the iodonium salts improves EUV light absorption, further improving resist stochasticity, sensitivity, and roughness. The components contained in the molecular resist composition of the present invention will be described below.

[0035] [Sulfonium salts] The molecular resist composition of the present invention contains a sulfonium salt represented by the following formula (1) or (2) as a main component. [ka] In the above formula, n is an integer of 1 to 3. A 1 is a hydrocarbyl group having 2 to 20 carbon atoms and containing a polymerizable functional group, and the hydrocarbyl group may contain a heteroatom. A 2 contains a polymerizable functional group, and Ar 1B It is a group that forms an alicyclic ring having 4 to 20 carbon atoms together with the two carbon atoms therein, and the alicyclic ring may contain a heteroatom. Ar 1A is an arylene group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the arylene group may be substituted with halogen atoms or hydrocarbyl groups having 1 to 20 carbon atoms which may contain heteroatoms. Ar 1B is a trivalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the trivalent aromatic hydrocarbon group may be substituted with halogen atoms or hydrocarbyl groups having 1 to 20 carbon atoms which may contain heteroatoms. Ar 2 is an aryl group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the aryl group may be substituted with halogen atoms or hydrocarbyl groups having 1 to 20 carbon atoms which may contain heteroatoms. Also, two Ar 1A , two Ar 1B , two Ar 2 , Ar1A and Ar 2 and, or Ar 1B and Ar 2 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. X - is the counter anion.

[0036] Above A 1 , A 2 The polymerizable functional group contained in is radically polymerizable.

[0037] In the formulas (1) and (2), n is an integer of 1 to 3.

[0038] In formula (1), A 1 is a hydrocarbyl group having 2 to 20 carbon atoms and containing a polymerizable functional group, and the hydrocarbyl group may contain a heteroatom. 2 contains a polymerizable functional group, and Ar 1B It is a group that forms an alicyclic ring having 4 to 20 carbon atoms together with the two carbon atoms therein, and the alicyclic ring may contain a heteroatom. Examples of the heteroatom include an oxygen atom, a sulfur atom, a nitrogen atom, and a halogen atom.

[0039] A 1 Preferred examples of A include an acryloyloxy group, a methacryloyloxy group, a cycloalkenyl group having 3 to 20 carbon atoms which may contain a heteroatom, a cycloalkenyloxy group having 3 to 20 carbon atoms which may contain a heteroatom, a cycloalkenylcarbonyloxy group having 3 to 20 carbon atoms which may contain a heteroatom, an alkenyl group having 2 to 20 carbon atoms which may contain a heteroatom, and an alkenyloxy group having 2 to 20 carbon atoms which may contain a heteroatom. 2 As for Ar 1B Preferably, the aryl group forms, together with the two carbon atoms therein, a cycloalkene ring having 4 to 20 carbon atoms which may contain a heteroatom, or a polycycle having 4 to 20 carbon atoms and one double bond which may contain a heteroatom.

[0040] A 1Specific examples of the group represented by the formula include, but are not limited to, the groups shown below. In the formula below, the dashed line indicates the group represented by Ar 1A Represents a bond with . [ka]

[0041] [ka]

[0042] [ka]

[0043] [ka]

[0044] A 2 Ar 1B Specific examples of the alicyclic ring having 4 to 20 carbon atoms formed together with the two carbon atoms in the alkyl group include, but are not limited to, the following: In the following formula, "C" represents an alkyl group such as Ar 1B represents the carbon atoms contained in [ka]

[0045] Among these, from the viewpoint of ease of introduction during the synthesis process and polymerization reactivity, A-1 to A-18, A-30 to A-43, and A-57 are preferred, and A-9 to A-18, A-30 to A-35, and A-40 are more preferred.

[0046] In formula (1), Ar 1A is an arylene group having 6 to 20 carbon atoms. Examples of the arylene group include a phenylene group, a naphthylene group, and an anthracenediyl group. In formula (2), Ar 1Bis a trivalent aromatic hydrocarbon group having 6 to 20 carbon atoms. Examples of the trivalent aromatic hydrocarbon group include groups obtained by removing three hydrogen atoms from benzene, naphthalene, and anthracene. In formulas (1) and (2), Ar 2 is an aryl group having 6 to 20 carbon atoms. Examples of the aryl group include a phenyl group, a naphthyl group, and an anthracenyl group. Among these, Ar 1A is preferably a phenylene group or a naphthylene group, more preferably a phenylene group, and Ar 1B is preferably a benzenetriyl group or a naphthalenetriyl group, more preferably a benzenetriyl group, and Ar 2 is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group.

[0047] Some or all of the hydrogen atoms of the arylene group, trivalent aromatic hydrocarbon group, and aryl group may be substituted with halogen atoms or hydrocarbyl groups having 1 to 20 carbon atoms and optionally containing heteroatoms. Examples of the halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. The hydrocarbyl groups having 1 to 20 carbon atoms may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0]. 2,6cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as a ]decanyl group, an adamantyl group, or an adamantylmethyl group; and aryl groups having 6 to 20 carbon atoms, such as a phenyl group, a naphthyl group, or an anthracenyl group. Some or all of the hydrogen atoms in the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH2- groups constituting the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, or a nitrogen atom, so that the hydrocarbyl group may contain a hydroxy group, a cyano group, a halogen atom, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a carbamate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), or the like.

[0048] Also, if present, two Ar 1A , two Ar 1B , two Ar 2 , Ar 1A and Ar 2 and, or Ar 1B and Ar 2 and may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, examples of the ring structure include, but are not limited to, those shown below. [ka] (In the formula, the dashed lines represent bonds.)

[0049] Specific examples of the cation of the sulfonium salt represented by formula (1) include, but are not limited to, those shown below. [ka]

[0050] [ka]

[0051] [ka]

[0052]

change

[0053]

change

[0054]

change

[0055]

change

[0056]

change

[0057]

change

[0058]

change

[0059]

change

[0060]

change

[0061]

change

[0062] [ka]

[0063] [ka]

[0064] Specific examples of the cation of the sulfonium salt represented by formula (2) include, but are not limited to, those shown below. [ka]

[0065] In formulas (1) and (2), X - is a counter anion. The counter anion is not particularly limited, but may be a non-nucleophilic anion. The counter anion is preferably a halide ion, a nitrate ion, a hydrogen sulfate ion, a hydrogen carbonate ion, a tetraphenylborate ion, or an anion represented by any of the following formulas (1-2) to (1-8). [ka]

[0066] In formulas (1-2) and (1-4), k1 and k2 each independently represent an integer of 1 to 4 (1, 2, 3, or 4). 1 and Rf 2 are each independently a hydrogen atom, a fluorine atom, or a fluorine-containing alkyl group having 1 to 6 carbon atoms, but all of Rf 1 and Rf 2 cannot simultaneously become a hydrogen atom.

[0067] In formula (1-2), R 41 is a hydrogen atom, a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, which may contain a heteroatom.

[0068] In formula (1-3), R42 is a hydrocarbyl group having 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, which may contain a hydrogen atom, a halogen atom, a hydroxy group, or a heteroatom, provided that this does not include those in which the hydrogen atoms on the carbon atoms at the α- and β-positions of the sulfo group are substituted with a fluorine atom or a fluoroalkyl group.

[0069] In formula (1-4), R 51 is a hydrogen atom, a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, which may contain a heteroatom.

[0070] In formula (1-5), R 52 is a hydrocarbyl group having 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, which may contain a hydrogen atom, a halogen atom, a hydroxy group, or a heteroatom, provided that this does not include those in which the hydrogen atoms on the carbon atoms at the α- and β-positions of the carboxy group are substituted with a fluorine atom or a fluoroalkyl group.

[0071] In formula (1-6), R 61 and R 62 are each independently a hydrocarbyl group having 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, which may contain a hetero atom.

[0072] In formula (1-7), R 71 ~R 73 are each independently a hydrocarbyl group having 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, which may contain a hetero atom.

[0073] In formula (1-8), R 81 R is a fluorine atom or a fluorinated hydrocarbyl group having 1 to 10 carbon atoms, and the fluorinated hydrocarbyl group may contain a hydroxy group, an ether bond, or an ester bond. 82 is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain a hydroxy group, an ether bond, or an ester bond. 81 and R 82may be bonded to each other to form a ring together with the atoms to which they are attached.

[0074] X - Among the above, the anion represented by formula (1-1) is preferably a halide ion, a nitrate ion, or an anion represented by any one of formulas (1-2) to (1-8), and more preferably a halide ion, a nitrate ion, or an anion represented by formula (1-3), (1-5), or (1-7).

[0075] R 41 , R 42 , R 51 , R 52 , R 61 , R 62 , R 71 , R 72 and R 73 The hydrocarbyl group having 1 to 50 carbon atoms and 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 50 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a tert-pentyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, and a tricyclo[5.2.1.0] 2,6cyclic saturated hydrocarbyl groups having 3 to 50 carbon atoms, such as a ]decanyl group, an adamantyl group, or an adamantylmethyl group; aryl groups having 6 to 50 carbon atoms, such as a phenyl group, a naphthyl group, or an anthracenyl group; and groups obtained by combining these. Some or all of the hydrogen atoms in the hydrocarbyl groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, or halogen atoms, and some of the -CH2- groups constituting the hydrocarbyl groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, or nitrogen atoms, so that the hydrocarbyl groups may contain hydroxy groups, cyano groups, halogen atoms, carbonyl groups, ether bonds, thioether bonds, ester bonds, sulfonate ester bonds, carbonate bonds, carbamate bonds, lactone rings, sultone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), etc.

[0076] R 81 The fluorinated hydrocarbyl group having 1 to 10 carbon atoms represented by the formula (I) is a group in which some or all of the hydrogen atoms of a hydrocarbyl group having 1 to 10 carbon atoms have been substituted with fluorine atoms. The hydrocarbyl group having 1 to 10 carbon atoms may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 41 , R 42 , R 51 , R 52 , R 61 , R 62 , R 71 , R 72 and R 73 Among the examples of hydrocarbyl groups having 1 to 50 carbon atoms represented by the following formula, those having 1 to 10 carbon atoms can be mentioned.

[0077] R 82 The hydrocarbyl 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 R 41 , R 42 , R 51 , R 52 , R 61 , R 62 , R 71 , R 72 and R 73Among the examples of hydrocarbyl groups having 1 to 50 carbon atoms represented by the following formula, those having 1 to 20 carbon atoms can be mentioned.

[0078] The anion represented by any one of formulas (1-2) to (1-8) preferably contains a polymerizable functional group, and may contain a hydrocarbyl group having 2 to 20 carbon atoms and optionally containing a heteroatom in its structure. Specific examples thereof include A in formula (1): 1 Examples of the group represented by the formula (I) include the same groups as those exemplified above.

[0079] Examples of the anion represented by formula (1-2) include, but are not limited to, the following: In the following formula, Ac is an acetyl group, and Rf 1 is the same as above. [ka]

[0080] [ka]

[0081] [ka]

[0082] [ka]

[0083] [ka]

[0084] [ka]

[0085] [ka]

[0086] [ka]

[0087] [ka]

[0088] [ka]

[0089] [ka]

[0090] [ka]

[0091] [ka]

[0092] Examples of the anion represented by formula (1-3) include, but are not limited to, those shown below. [ka]

[0093] [ka]

[0094] [ka]

[0095] [ka]

[0096] [ka]

[0097] [ka]

[0098] Examples of the anion represented by formula (1-4) include, but are not limited to, those shown below. [ka]

[0099] [ka]

[0100] Examples of the anion represented by formula (1-5) include, but are not limited to, those shown below. [ka]

[0101] [ka]

[0102] [ka]

[0103] Examples of the anion represented by formula (1-6) include, but are not limited to, those shown below. [ka]

[0104] [ka]

[0105] Examples of the anion represented by formula (1-7) include, but are not limited to, those shown below. [ka]

[0106] [ka]

[0107] [ka]

[0108] Examples of the anion represented by formula (1-8) include, but are not limited to, those shown below. [ka]

[0109] [ka]

[0110] Specific examples of the sulfonium salt represented by formula (1) or (2) include any combination of the specific anions and specific cations described above.

[0111] From the viewpoint of pattern formation, it is preferable that the sulfonium salt represented by formula (1) or (2) has a polymerizable functional group in both the cation and anion that form the salt.

[0112] The sulfonium salts represented by formula (1) or (2) may be used singly or in combination of two or more kinds. From the viewpoint of improving the uniformity of the components, however, it is preferable to use one kind alone or two kinds in combination.

[0113] The sulfonium salts represented by formula (1) or (2) can be synthesized by combining known organic chemical methods. For example, an ion-exchange reaction is carried out by mixing onium salt intermediates having the desired cation and anion. The ion-exchange reaction can be easily achieved by known methods, and reference can be made to, for example, JP-A-2007-145797.

[0114] [Iodonium salts] The molecular resist composition of the present invention contains an iodonium salt containing an iodonium cation represented by the following formula (1-1) and a halide ion, a nitrate ion, a hydrogen sulfate ion, a hydrogen carbonate ion, a tetraphenylborate ion, or an anion represented by any of the following formulas (1-2) to (1-8). [ka] (In the formula, R 31 , R 32 are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. [ka] (In the formula, k1 and k2 are each independently 1, 2, 3, or 4. Rf 1 and Rf 2 are each independently a hydrogen atom, a fluorine atom, or a fluorine-containing alkyl group having 1 to 6 carbon atoms, but all of Rf 1 and Rf 2 R cannot be a hydrogen atom at the same time. 41 R is a hydrogen atom, a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 42R is a hydrocarbyl group having 1 to 50 carbon atoms which may contain a hydrogen atom, a halogen atom, a hydroxy group, or a heteroatom, provided that this does not include those in which the hydrogen atoms on the carbon atoms at the α- and β-positions of the sulfo group are substituted with a fluorine atom or a fluoroalkyl group. 51 R is a hydrogen atom, a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 52 R is a hydrocarbyl group having 1 to 50 carbon atoms which may contain a hydrogen atom, a halogen atom, a hydroxy group, or a heteroatom, provided that this does not include those in which the hydrogen atoms on the carbon atoms at the α- and β-positions of the carboxy group are substituted with a fluorine atom or a fluoroalkyl group. 61 and R 62 R are each independently a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 71 ~R 73 R are each independently a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 81 R is a fluorine atom or a fluorinated hydrocarbyl group having 1 to 10 carbon atoms, and the fluorinated hydrocarbyl group may contain a hydroxy group, an ether bond, or an ester bond. 82 is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain a hydroxy group, an ether bond, or an ester bond. 81 and R 82 may be bonded to each other to form a ring together with the atoms to which they are attached.

[0115] In the above formula (1-1), R 31 , R 32 Examples of the halogen atom represented by R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. 31 , R 32The hydrocarbyl group having 1 to 30 carbon atoms 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 30 carbon atoms such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0]. 2,6 ] cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms, such as a decyl group, an adamantyl group, or an adamantylmethyl group; and aryl groups having 6 to 30 carbon atoms, such as a phenyl group, a naphthyl group, or an anthracenyl group. Some or all of the hydrogen atoms in the hydrocarbyl groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, or halogen atoms, and some of the -CH2- groups in the hydrocarbyl groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, or nitrogen atoms, so that the hydrocarbyl groups may contain hydroxy groups, cyano groups, halogen atoms, carbonyl groups, ether bonds, thioether bonds, ester bonds, sulfonate ester bonds, carbonate bonds, carbamate bonds, lactone rings, sultone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), or the like.

[0116] In addition, X in the above formula (1) or (2) - is the same as the counter anion of the iodonium cation represented by the formula (1-1), that is, the anion X of the sulfonium salt - and the counter anion of the iodonium cation may have the same structure. Furthermore, independently or in addition, the anion represented by any one of the formulas (1-2) to (1-8) may contain a polymerizable functional group.

[0117] Specific examples of the group represented by the formula (1-1) include, but are not limited to, the groups shown below. The anions represented by any of the formulas (1-2) to (1-8) are the same as those for sulfonium salts. [ka]

[0118] [ka]

[0119] The content of the iodonium salt is preferably 1 to 100 parts by mass, more preferably 5 to 15 parts by mass, relative to 100 parts by mass of the sulfonium salt. The iodonium salt may be used alone or in combination of two or more kinds.

[0120] The molecular resist composition of the present invention is characterized by the addition of an iodonium salt in addition to the sulfonium salt, which is the main component. As described below, the addition of the iodonium salt increases EUV light absorption, improving the resist's stochasticity, sensitivity, and roughness. Furthermore, the iodonium salt has a high EUV light absorption rate, and the iodonium salt efficiently generates radicals upon photolysis. The radicals thus generated initiate radical polymerization of the polymerizable substituent of the sulfonium salt, efficiently increasing the molecular weight, which in turn improves the resist's contrast, sensitivity, and resolution.

[0121] [Organic solvents] The molecular resist composition of the present invention contains an organic solvent. The solvent is not particularly limited as long as it can dissolve the sulfonium salt represented by formula (1) or (2) and the iodonium salt represented by formula (1-1) and can form a film. Examples of such organic solvents include ketones such as cyclohexanone and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol (DAA); ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono-tert-butyl ether acetate; and lactones such as γ-butyrolactone.

[0122] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, DAA, γ-butyrolactone, and mixed solvents thereof are preferred.

[0123] In the molecular resist composition of the present invention, the content of the organic solvent is preferably 200 to 5,000 parts by mass per 100 parts by mass of the sulfonium salt represented by formula (1) or (2). The organic solvent may be used alone or in combination of two or more.

[0124] The molecular resist composition of the present invention is characterized by comprising, as main components, a sulfonium salt represented by formula (1) or (2), an iodonium salt represented by formula (1-1), and an organic solvent, but not a base polymer. When a resist film obtained from the molecular resist composition of the present invention is exposed to EB or EUV, the exposed portions become insoluble in an alkaline developer, allowing the formation of a negative pattern. The base polymer is the main component of a polymeric resist composition, and refers to a polymer whose solubility in a developer changes due to the action of the acid generated from the acid generator.

[0125] Conventional resist compositions, which have a multi-component polymer as the main component (base polymer) and also contain a photoacid generator and sensitivity adjuster, have difficulty distributing the components uniformly throughout the resist film, which has a significant impact on roughness, particularly in the formation of fine patterns using EUV lithography. In addition, the fact that polymers are materials with large molecular sizes also has an impact, resulting in deterioration of LWR and CDU.

[0126] In contrast, the molecular resist composition of the present invention does not contain multi-component polymer components and has a very simple structure, which improves the uniformity of the components in the resist film. Furthermore, because the main components are low-molecular-weight compounds, the molecular size is small, which can improve LWR and CDU, particularly when forming fine patterns by EB lithography and EUV lithography.

[0127] The molecular resist composition of the present invention enables pattern formation by utilizing the photoreaction-induced structural change of the sulfonium salt, the main component, and polymerization of the polymerizable functional groups. By using a sulfonium salt represented by formula (1) or (2), photodecomposition of the sulfonium salt and radical polymerization of the polymerizable groups derived from radicals generated during exposure, particularly in EB lithography and EUV lithography, significantly changes the solubility in alkaline developers (insolubilization), enabling the formation of negative patterns. In particular, when a sulfonium salt is used in which both the cation and anion forming the sulfonium salt have polymerizable functional groups, all of the salt components contribute to pattern formation during radical polymerization during exposure, effectively enhancing the dissolution contrast between exposed and unexposed areas. Because the structural change occurs during exposure, acid diffusion, as occurs with conventional polymer-based chemically amplified resist compositions, does not occur, thus preventing image blurring due to acid diffusion. The resolution performance of the molecular resist composition of the present invention is superior to that of conventional polymer-based chemically amplified resist compositions, and its resistance to pattern collapse makes it extremely effective for forming fine patterns.

[0128] The molecular resist composition of the present invention is characterized by the addition of an iodonium salt to the main component, sulfonium salt. The addition of the iodonium salt increases the absorption of EUV light, improving the stochasticity, sensitivity, and roughness of the resist. Furthermore, the radicals generated during photodecomposition of the iodonium salt, which has high absorption of EUV light, initiate radical polymerization of the polymerizable substituent of the sulfonium salt, efficiently increasing the molecular weight and leading to improvements in the contrast, sensitivity, and resolution of the resist.

[0129] The molecular resist composition of the present invention does not contain a polymer component that functions as a base polymer, but may contain a polymer component that is used as an additive (i.e., is not a main component), such as a polymer used as a surfactant, if necessary, in order to form a pattern using the sulfonium salt represented by the above-mentioned formula (1) or (2).

[0130] [Other ingredients] The molecular resist composition of the present invention may contain a radical scavenger as another component. By adding a radical scavenger, it is possible to control the photoreaction during photolithography and adjust the sensitivity.

[0131] Examples of such radical scavengers include hindered phenols, quinones, hindered amines, and thiol compounds. Specific examples of hindered phenols include dibutylhydroxytoluene (BHT) and 2,2'-methylenebis(4-methyl-6-tert-butylphenol). Examples of quinones include 4-methoxyphenol (methoquinone) and hydroquinone. Examples of hindered amines include 2,2,6,6-tetramethylpiperidine and 2,2,6,6-tetramethylpiperidine-N-oxy radical. Examples of thiols include dodecanethiol, hexadecanethiol, and benzenethiol. When the molecular resist composition of the present invention contains the radical scavengers, the content thereof is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the sulfonium salt. The radical scavengers may be used singly or in combination of two or more.

[0132] The molecular resist composition of the present invention may contain a surfactant as another component. Examples of the surfactant include FC-4432 and FC-4430 (manufactured by 3M), and PF636, PF656, PF6320, and PF6520 (manufactured by Omnova). When the molecular resist composition of the present invention contains a surfactant, the content thereof is preferably 0.001 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the sulfonium salt. The surfactant may be used alone or in combination of two or more types.

[0133] [Pattern formation method] When the molecular resist composition of the present invention is used in various integrated circuit manufacturing, known lithography techniques can be applied.For example, as a pattern forming method, the method can include the steps of forming a resist film on a substrate using the molecular resist composition described above, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer.

[0134] First, the molecular resist composition 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 pre-baked on a hot plate, preferably at 60 to 150°C for 10 seconds to 30 minutes, more preferably at 80 to 120°C for 30 seconds to 20 minutes, to form a resist film.

[0135] Next, the resist film is exposed to high-energy radiation. Examples of the high-energy radiation include ultraviolet radiation, far ultraviolet radiation, EB, EUV, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation. When ultraviolet radiation, far ultraviolet radiation, EUV, 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 100 μC / cm 2 directly or using a mask for forming a desired pattern. 2 approximately, more preferably 0.5 to 50 μC / cm 2The molecular resist composition 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, gamma rays, and synchrotron radiation, and is particularly suitable for fine patterning using EB or EUV.

[0136] The molecular resist composition of the present invention forms an image by structurally changing the sulfonium salt during exposure, so it does not necessarily require the post-exposure bake (PEB) required for chemically amplified resist compositions. If PEB is performed, it is preferably performed on a hot plate or in an oven after exposure, preferably at 30 to 120°C for 10 seconds to 30 minutes, more preferably at 60 to 100°C for 30 seconds to 20 minutes.

[0137] When the molecular resist composition of the present invention is a negative type, the irradiated portion becomes insoluble in a developer, and the unexposed portion becomes soluble. On the other hand, when the molecular resist composition of the present invention is a positive type, the irradiated portion becomes soluble in a developer, and the unexposed portion becomes insoluble. A pattern is formed by radical polymerization of the sulfonium salt contained in the molecular resist composition of the present invention upon exposure to light. However, if the polymer is insoluble in an alkaline developer or an organic solvent developer described below and the unreacted sulfonium salt is soluble, a negative pattern is formed.

[0138] After exposure or PEB, the exposed resist film is developed using a developer, such as an aqueous alkaline solution of 0.1 to 10 mass %, preferably 2 to 5 mass %, of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), or the like, for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by a conventional method such as dipping, puddling, or spraying, to form a desired pattern.

[0139] After development with an alkaline developer, the pattern is rinsed with pure water and then dried by spin drying. To reduce the stress on the pattern during drying and prevent it from collapsing, it is effective to use a rinse solution containing a surfactant or to use supercritical rinsing with carbon dioxide or the like.

[0140] The molecular resist composition of the present invention can also be used to obtain a negative pattern by organic solvent development. The developer used in this case includes 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, cyclohexyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, crotonate, etc. Examples of organic solvents include ethyl lactate, 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, ethyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, and 2-phenylethyl acetate. These organic solvents may be used alone or in combination of two or more.

[0141] After development, rinsing is performed as necessary. A preferred rinsing solution is a solvent that is miscible with the developer but does not dissolve the resist film. 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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] Examples of aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0146] 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. [Example]

[0147] 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. The apparatuses used are as follows. IR: Thermo Fisher Scientific NICOLET 6700 · 1 H-NMR: ECA-500 manufactured by JEOL Ltd. MALDI TOF-MS: JEOL Ltd., S3000

[0148] [1] Synthesis of sulfonium salts [Synthesis Example 1-1] Synthesis of PAG-1

[0149] [ka]

[0150] Under a nitrogen atmosphere, raw material M-1 (43.1 g), triethylamine (42.5 g), and 4-dimethylaminopyridine (1.22 g) were dissolved in methylene chloride (431 g). The reaction mixture was cooled to below 10°C, and methacrylic anhydride (55.8 g) was added dropwise. After the addition, the mixture was aged at 20°C for 12 hours. After aging, the reaction mixture was cooled, and saturated aqueous sodium bicarbonate (200 g) was added dropwise to quench the reaction. This was followed by standard aqueous workup, followed by distillation of the solvent, and recrystallization with diisopropyl ether to obtain PAG-1 as white crystals (yield: 58.1 g, 92%).

[0151] The spectral data of PAG-1 are shown below. The nuclear magnetic resonance spectrum ( 1 The results of H-NMR / DMSO-d6) are shown in Figure 1. IR(D-ATR):3371,2973,2927,1737,1677,1637,1608,1477,1454,1379,1317, 1293,1276,1231,1182,1120,1038,1011,947,877,807,714,650,613,583,489 cm -1 . MALDI-TOFMS: POSITIVE [M + ] 599 (C 36 H 39 O6S + equivalent) NEGATIVE [M - ] 35 (Cl - equivalent)

[0152] [Synthesis Example 1-2] Synthesis of PAG-2 [ka]

[0153] PAG-2 was synthesized (14.4 g, yield 89%) in the same manner as in Synthesis Example 1-1, except that methacrylic anhydride was changed to acrylic chloride.

[0154] The spectral data of PAG-2 are shown below. The nuclear magnetic resonance spectrum ( 1 The results of H-NMR / DMSO-d6) are shown in Figure 2. IR(D-ATR):3607,3366,2974,2926,1741,1633,1577,1476,1403,1293,1277,1243,1180,1139,1102,1016,982,901,802,718,667,611,588 cm -1 . MALDI-TOFMS: POSITIVE [M + ] 557 (C 33 H 33 O6S + equivalent) NEGATIVE [M - ] 35 (Cl - equivalent)

[0155] [Synthesis Example 1-3] Synthesis of PAG-3 [ka]

[0156] Under a nitrogen atmosphere, PAG-1 (14.6 g), raw material M-2 (10.3 g), methylene chloride (40 g), and water (40 g) were charged and stirred for 30 minutes. The organic layer was then separated and washed five times with water (40 g). The solvent in the organic layer was evaporated, and PAG-3 was recrystallized with diisopropyl ether to obtain white crystals (yield: 9.3 g, 75%).

[0157] The spectral data of PAG-3 is shown below. The nuclear magnetic resonance spectrum ( 1 The results of H-NMR / DMSO-d6) are shown in Figure 3. IR(D-ATR):3506,2929,2855,1737,1637,1476,1452,1379,1290,1182,1110,1036,1011,990,947,877,807,755,657,609,582,544,528,457 cm -1 . MALDI-TOFMS: POSITIVE [M + ] 599 (C 36 H 39 O6S + equivalent) NEGATIVE [M - ] 385 (C 14 H 25 O6S3 - equivalent)

[0158] [Synthesis Example 1-4] Synthesis of PAG-4 [ka]

[0159] PAG-4 was synthesized (10.3 g, yield 84%) in the same manner as in Synthesis Example 1-3, except that PAG-1 was changed to PAG-2.

[0160] The spectral data of PAG-4 is shown below. The nuclear magnetic resonance spectrum ( 1 The results of H-NMR / DMSO-d6) are shown in Figure 4. IR(D-ATR):3489,3046,2933,2856,1743,1633,1579,1477,1451,1401,1379,1293,1242, 1180,1136,1107,1015,983,959,901,802,764,718,656,628,610,586,544,528,458,403 cm -1 . MALDI-TOFMS: POSITIVE [M + ] 557 (C 33 H 33 O6S + equivalent) NEGATIVE [M - ] 385 (C 14 H 25 O6S3 - equivalent)

[0161] [Synthesis Example 1-5] Synthesis of PAG-5 [ka]

[0162] PAG-5 was synthesized (13.7 g, yield 90%) in the same manner as in Synthesis Example 1-4, except that the raw material M-2 was changed to sodium styrenesulfonate.

[0163] The spectral data of PAG-5 is shown below. The nuclear magnetic resonance spectrum ( 1 The results of H-NMR / DMSO-d6) are shown in Figure 5. IR(D-ATR):3048,2972,2926,1743,1633,1477,1399,1294,1277,1240,1206,11 80,1137,1104,1060,1033,1010,987,975,902,841,804,714,674,611,584,553 cm -1 . MALDI-TOFMS: POSITIVE [M + ] 557 (C 33 H 33 O6S + equivalent) NEGATIVE [M - ] 183 (C8H7O3S - equivalent)

[0164] [Synthesis Example 1-6] Synthesis of PAG-6 [ka]

[0165] PAG-6 was synthesized (16.1 g, yield 96%) in the same manner as in Synthesis Example 1-3, except that the raw material M-2 was changed to sodium styrenesulfonate.

[0166] The spectral data of PAG-6 is shown below. The nuclear magnetic resonance spectrum ( 1 The results of H-NMR / DMSO-d6 are shown in Figure 6. IR(D-ATR):3453,2972,2927,1729,1637,1475,1452,1379,1317,1294,1276,1216 ,1202,1180,1119,1034,1010,943,891,843,810,714,675,612,582,557,505,487 cm -1 . MALDI-TOFMS: POSITIVE [M + ] 599 (C 36 H 39 O6S + equivalent) NEGATIVE [M - ] 183 (C8H7O3S - equivalent)

[0167] [Synthesis Example 1-7] Synthesis of PAG-7 [ka]

[0168] PAG-7 was synthesized (15.9 g, yield 86%) in the same manner as in Synthesis Example 1-4, except that raw material M-2 was changed to raw material M-3.

[0169] The spectral data of PAG-7 is shown below. The nuclear magnetic resonance spectrum ( 1 The results of H-NMR / DMSO-d6) are shown in Figure 7. IR(D-ATR):3480,3050,2971,2928,1743,1633,1608,1476,1404,1377,1328,1245,118 1,1139,1101,1071,1015,991,902,860,840,802,777,712,667,642,610,574,552,521 cm -1 . MALDI-TOFMS: POSITIVE [M + ] 557 (C 33 H 33 O6S + equivalent) NEGATIVE [M - ] 359 (C 12 H8F5O5S - equivalent)

[0170] [Synthesis Example 1-8] Synthesis of PAG-8 [ka]

[0171] PAG-8 was synthesized (32.1 g, yield 92%) in the same manner as in Synthesis Example 1-1, except that raw material M-1 was changed to raw material M-4.

[0172] The spectral data of PAG-8 is shown below. The nuclear magnetic resonance spectrum ( 1The results of H-NMR / DMSO-d6) are shown in Figure 8. IR(D-ATR):3379,2974,2926,1735,1636,1477,1446,1379,1317,1293,1277 ,1182,1120,1040,1011,947,878,808,751,714,685,649,613,568,522,492 cm -1 . MALDI-TOFMS: POSITIVE [M + ] 487 (C 30 H 31 O4S + equivalent) NEGATIVE [M - ] 35 (Cl - equivalent)

[0173] [Synthesis Example 1-9] Synthesis of PAG-9 [ka]

[0174] PAG-9 was synthesized (16.5 g, yield 89%) in the same manner as in Synthesis Example 1-3, except that PAG-1 was changed to PAG-8.

[0175] The spectral data of PAG-9 is shown below. The nuclear magnetic resonance spectrum ( 1 The results of H-NMR / DMSO-d6) are shown in Figure 9. IR(D-ATR):3506,3056,2929,2854,1738,1637,1476,1448,1379,1289,1258,11 83,1110,1012,990,948,892,852,807,754,713,686,657,609,582,544,528,456 cm -1 . MALDI-TOFMS: POSITIVE [M + ] 487 (C 30 H 31 O4S + equivalent) NEGATIVE [M - ] 385 (C14 H 25 O6S3 - equivalent)

[0176] [Synthesis Examples 1-10 to 1-20] Synthesis of PAG-10 to PAG-20 PAG-10 to PAG-20 were synthesized by various organic synthesis reactions. [ka]

[0177] [ka]

[0178] [2] Synthesis of base polymer for comparative resist composition [Comparative Synthesis Example 1] Synthesis of Polymer P-1 Under a nitrogen atmosphere, p-hydroxystyrene (27.8 g), 1-methylcyclopentyl methacrylate (72.2 g), and dimethyl 2,2'-azobisisobutyrate (6.08 g) were dissolved in PGMEA (155 g) to prepare a solution. This solution was added dropwise to PGMEA (78 g) stirred at 80°C under a nitrogen atmosphere over 6 hours. After the addition, the mixture was stirred for 2 hours while maintaining the temperature at 80°C, and then cooled to room temperature. The reaction solution was then added dropwise to n-hexane (3,000 g). The precipitated solid was filtered and dried in vacuum at 50°C for 20 hours to obtain polymer P-1 as a white powder. The yield was 85 g, or 85%. [ka]

[0179] [Comparative Synthesis Example 2] Synthesis of Polymer P-2 Polymer P-2 was produced in the same manner as in Comparative Synthesis Example 1, except that the types and blending ratio of the monomers were changed. [ka]

[0180] [3] Preparation of resist composition [Examples 1-1 to 1-20, Comparative Examples 1-1 to 1-8] Molecular resist compositions (R-1 to R-20) were prepared by dissolving sulfonium salts (PAG-1 to PAG-20) in a solvent according to the compositions shown in Table 1 below, and filtering the resulting solutions through a 0.2 μm Teflon (registered trademark) filter. Comparative resist compositions (CR-1 to CR-8) were also prepared by mixing a polymer, a photoacid generator, a sensitivity adjuster, a surfactant, and a solvent according to the compositions shown in Table 1 below, and then filtering the mixture through a 0.2 μm Teflon (registered trademark) filter.

[0181] [Table 1]

[0182] In Table 1, the iodonium salts (I-1 to I-3), photoacid generators (PAG-A to PAG-C), sensitivity adjusters (QA, QB), nonionic monomer (Y-1), surfactant (SF-1), and solvents are as follows: [ka]

[0183] [ka]

[0184] [ka]

[0185] SF-1: PF636 (Omnova) Solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (diacetone alcohol)

[0186] [4] EB lithography evaluation [Examples 2-1 to 2-20, Comparative Examples 2-1 to 2-8] Each resist composition (R-1 to R-20, CR-1 to CR-8) was spin-coated onto a Si substrate coated with a 60-nm-thick anti-reflective coating (DUV-42, manufactured by Nissan Chemical Co., Ltd.) and prebaked at 100°C for 60 seconds using a hot plate to produce a 50-nm-thick resist film. The resist film was exposed using an Elionix EB lithography system (ELS-F125, accelerating voltage 125 kV), subjected to PEB for 60 seconds on a hot plate at the temperature listed in Table 2, and developed for 30 seconds in a 2.38 wt% TMAH aqueous solution to form a pattern. In Examples 2-1 to 2-20, Comparative Examples 2-2, and Comparative Examples 2-5 to 2-8, the exposed portions of the resist film remained, exhibiting negative tone characteristics. In Comparative Examples 2-3 and 2-4, the unexposed portions remained, exhibiting positive tone characteristics. As a result, negative or positive line-and-space (LS) patterns with a space width of 40 nm and a pitch of 80 nm were obtained. In Comparative Example 2-1, no pattern formation was observed. The sensitivity, LWR, and limiting resolution of the obtained LS patterns were evaluated according to the following methods. The results are shown in Table 2.

[0187] [Sensitivity evaluation] The LS pattern was observed using a CD-SEM (CG-5000) manufactured by Hitachi High-Tech Corporation, and the optimum exposure dose Eop (μC / cm) for obtaining an LS pattern with a space width of 40 nm and a pitch of 80 nm was determined. 2 ) was calculated and used as the sensitivity.

[0188] [LWR rating] The LS pattern obtained by irradiation with the optimum exposure dose Eop was measured at 10 points in the longitudinal direction of the space width using a Hitachi High-Tech CD-SEM (CG-5000). From the results, three times the standard deviation (σ) (3σ) was calculated and used as the LWR. The smaller this value, the less roughness and the more uniform the space width pattern obtained.

[0189] [Limiting resolution evaluation] The minimum line width (nm) of the LS pattern separated at the optimum exposure dose Eop was defined as the limiting resolution.

[0190] [Table 2]

[0191] The results shown in Table 2 demonstrate that the molecular resist composition of the present invention is superior in sensitivity, LWR, and limiting resolution to a polymeric positive resist composition and a positive resist composition using a nonionic monomer in forming a negative pattern by alkaline aqueous solution development in EB lithography. It was also found that the addition of an iodonium salt results in excellent sensitivity and LWR. The results of Examples 2-3 to 2-5 and Comparative Examples 2-6 to 2-8 clearly demonstrate that, even though the main component of the molecular resist composition (sulfonium salt having a polymerizable functional group) is the same, the former, which contains the iodonium salt used in the present invention, exhibits a lower optimal exposure dose (improved sensitivity) and a smaller LWR than the latter, which does not contain the iodonium salt.

[0192] [5] EUV lithography evaluation [Examples 3-1 to 3-20, Comparative Examples 3-1 to 3-8] Each resist composition (R-1 to R-20, CR-1 to CR-8) was spin-coated onto a Si substrate coated with a 20 nm thick silicon-containing spin-on hard mask (SHB-A940, manufactured by Shin-Etsu Chemical Co., Ltd.) (43% silicon by mass) and pre-baked at 100°C for 60 seconds on a hot plate to produce a 40 nm thick resist film. A 22 nm LS1:1 pattern was exposed using an ASML EUV scanner NXE3300 (NA 0.33, σ 0.9, 90-degree dipole illumination), followed by PEB for 60 seconds on a hot plate at the temperature listed in Table 3, and development for 30 seconds in a 2.38% by mass TMAH aqueous solution to form a pattern. In Examples 3-1 to 3-20, Comparative Examples 3-2, and 3-5 to 3-8, the exposed portions of the resist film remained, while in Comparative Examples 3-3 and 3-4, the unexposed portions remained. As a result, a negative or positive LS pattern with a space width of 22 nm and a pitch of 44 nm was obtained. In Comparative Example 3-1, no pattern formation was observed. The sensitivity, LWR, and limiting resolution of the obtained LS patterns were evaluated according to the following methods. The results are shown in Table 3.

[0193] [Sensitivity evaluation] The LS pattern was observed using a CD-SEM (CG-5000) manufactured by Hitachi High-Tech Corporation, and the optimum exposure dose Eop (mJ / cm) for obtaining an LS pattern with a space width of 22 nm and a pitch of 44 nm was determined. 2 ) was calculated and used as the sensitivity.

[0194] [LWR rating] The LS pattern obtained by irradiation with the optimum exposure dose Eop was measured at 10 points in the longitudinal direction of the space width using a Hitachi High-Tech CD-SEM (CG-5000). From the results, three times the standard deviation (σ) (3σ) was calculated and used as the LWR. The smaller this value, the less roughness and the more uniform the space width pattern obtained.

[0195] [Limiting resolution evaluation] The minimum line width (nm) of the LS pattern separated at the optimum exposure dose Eop was defined as the limiting resolution.

[0196] [Table 3]

[0197] The results shown in Table 3 demonstrate that the molecular resist composition of the present invention, in EUV lithography as well as EB lithography, is superior in sensitivity, LWR, and limiting resolution to polymer-based positive resist compositions and positive resist compositions using nonionic monomers in forming negative patterns by alkaline aqueous solution development. It was also found that the addition of an iodonium salt results in excellent sensitivity and LWR. The results of Examples 3-3 to 3-5 and Comparative Examples 3-6 to 3-8 clearly demonstrate that, even though the main component of the molecular resist composition (sulfonium salt having a polymerizable functional group) is the same, the former, which contains the iodonium salt used in the present invention, has a lower optimal exposure dose (improved sensitivity) and a smaller LWR than the latter, which does not contain the iodonium salt.

[0198] The present specification includes the following aspects. [1]: A molecular resist composition comprising a sulfonium salt represented by the following formula (1) or (2), an iodonium salt containing an iodonium cation represented by the following formula (1-1) and a halide ion, a nitrate ion, a hydrogen sulfate ion, a hydrogen carbonate ion, a tetraphenylborate ion, or an anion represented by any of the following formulas (1-2) to (1-8), and an organic solvent, but not containing a base polymer. [ka] (wherein n is an integer of 1 to 3. A 1 A is a hydrocarbyl group having 2 to 20 carbon atoms and containing a polymerizable functional group, and the hydrocarbyl group may contain a heteroatom. 2 contains a polymerizable functional group, and Ar 1B It is a group that forms an alicyclic ring having 4 to 20 carbon atoms together with the two carbon atoms therein, and the alicyclic ring may contain a heteroatom. 1Ais an arylene group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the arylene group may be substituted with a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 1B is a trivalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the trivalent aromatic hydrocarbon group may be substituted with a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 2 is an aryl group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the aryl group may be substituted with a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 1A , two Ar 1B , two Ar 2 , Ar 1A and Ar 2 and, or Ar 1B and Ar 2 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. - is the counter anion.) [ka] (In the formula, R 31 , R 32 are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. [ka] (In the formula, k1 and k2 are each independently 1, 2, 3, or 4. Rf 1 and Rf 2 are each independently a hydrogen atom, a fluorine atom, or a fluorine-containing alkyl group having 1 to 6 carbon atoms, but all of Rf 1 and Rf 2 R cannot be a hydrogen atom at the same time. 41 R is a hydrogen atom, a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 42R is a hydrocarbyl group having 1 to 50 carbon atoms which may contain a hydrogen atom, a halogen atom, a hydroxy group, or a heteroatom, provided that this does not include those in which the hydrogen atoms on the carbon atoms at the α- and β-positions of the sulfo group are substituted with a fluorine atom or a fluoroalkyl group. 51 R is a hydrogen atom, a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 52 R is a hydrocarbyl group having 1 to 50 carbon atoms which may contain a hydrogen atom, a halogen atom, a hydroxy group, or a heteroatom, provided that this does not include those in which the hydrogen atoms on the carbon atoms at the α- and β-positions of the carboxy group are substituted with a fluorine atom or a fluoroalkyl group. 61 and R 62 R are each independently a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 71 ~R 73 R are each independently a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. 81 R is a fluorine atom or a fluorinated hydrocarbyl group having 1 to 10 carbon atoms, and the fluorinated hydrocarbyl group may contain a hydroxy group, an ether bond, or an ester bond. 82 is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain a hydroxy group, an ether bond, or an ester bond. 81 and R 82 may be bonded to each other to form a ring together with the atoms to which they are attached. [2]: The above A 1 is an acryloyloxy group, a methacryloyloxy group, a cycloalkenyl group having 3 to 20 carbon atoms which may contain a heteroatom, a cycloalkenyloxy group having 3 to 20 carbon atoms which may contain a heteroatom, a cycloalkenylcarbonyloxy group having 3 to 20 carbon atoms which may contain a heteroatom, an alkenyl group having 2 to 20 carbon atoms which may contain a heteroatom, or an alkenyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, 2 But, Ar 1BThe molecular resist composition according to [1], characterized in that the group is a group that, together with the two carbon atoms in the group, forms a cycloalkene ring having 4 to 20 carbon atoms which may contain a heteroatom, or a polycycle having 4 to 20 carbon atoms and one double bond which may contain a heteroatom. [3]: The above X - is the same as the counter anion of the iodonium cation represented by the formula (1-1). [4]: The molecular resist composition according to any one of [1] to [3], wherein the anion represented by any one of the formulas (1-2) to (1-8) contains a polymerizable functional group. [5]: The molecular resist composition according to any one of [1] to [4], further comprising a radical scavenger. [6]: The molecular resist composition according to any one of [1] to [5], further comprising a surfactant. [7]: A pattern forming method comprising the steps of: forming a resist film on a substrate using a molecular resist composition according to any one of [1] to [6]; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developer. [8]: The pattern forming method according to [7], characterized in that an alkaline aqueous solution is used as the developer to dissolve exposed areas and to obtain a positive pattern in which unexposed areas do not dissolve. [9]: The pattern forming method according to [7], characterized in that an organic solvent or an alkaline aqueous solution is used as the developer to dissolve the unexposed areas, thereby obtaining a negative pattern in which the exposed areas do not dissolve.

[10] : The organic solvent of the developer may be 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, cyclohexyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, or 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, ethyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, and 2-phenylethyl acetate.

[11] : The pattern formation method according to any one of [7] to

[10] , wherein the high-energy beam is an electron beam or extreme ultraviolet light.

[0199] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention.

Claims

1. A molecular resist composition comprising: a sulfonium salt represented by the following formula (1) or (2); an iodonium salt containing an iodonium cation represented by the following formula (1-1) and a halide ion, a nitrate ion, a hydrogen sulfate ion, a hydrogen carbonate ion, a tetraphenylborate ion, or an anion represented by any of the following formulas (1-2) to (1-8); and an organic solvent, but not containing a base polymer. 【Chemistry 1】 (wherein n is an integer of 1 to 3. A １ is a hydrocarbyl group having 2 to 20 carbon atoms and containing a polymerizable functional group, and the hydrocarbyl group may contain a heteroatom. ２ contains a polymerizable functional group, and Ar １Ｂ Ar is a group that forms an alicyclic ring having 4 to 20 carbon atoms together with the two carbon atoms in the ring, and the alicyclic ring may contain a heteroatom. １Ａ is an arylene group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the arylene group may be substituted with a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. １Ｂ is a trivalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the trivalent aromatic hydrocarbon group may be substituted with a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. ２ is an aryl group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the aryl group may be substituted with a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. １Ａ , two Ar １Ｂ , two Ar ２ , Ar １Ａ and Ar ２ and, or Ar １Ｂ and Ar ２ and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. － is the counter anion.) 【Chemistry 2】 (In the formula, R ３１ , R ３２ are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. 【Transformation 3】 (In the formula, k1 and k2 are each independently 1, 2, 3, or 4. Rf １ and Rf ２ are each independently a hydrogen atom, a fluorine atom or a fluorine-containing alkyl group having 1 to 6 carbon atoms, but all Rf １ and Rf ２ cannot be a hydrogen atom at the same time. ４１ R is a hydrogen atom, a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. ４２ is a hydrocarbyl group having 1 to 50 carbon atoms which may contain a hydrogen atom, a halogen atom, a hydroxy group, or a heteroatom, provided that this does not include those in which the hydrogen atoms on the carbon atoms at the α- and β-positions of the sulfo group are substituted with a fluorine atom or a fluoroalkyl group. ５１ R is a hydrogen atom, a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. ５２ R is a hydrocarbyl group having 1 to 50 carbon atoms which may contain a hydrogen atom, a halogen atom, a hydroxy group, or a heteroatom, provided that this does not include those in which the hydrogen atoms on the carbon atoms at the α- and β-positions of the carboxy group are substituted with a fluorine atom or a fluoroalkyl group. ６１ and R ６２ R are each independently a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. ７１ ~R ７３ R are each independently a hydrocarbyl group having 1 to 50 carbon atoms which may contain a heteroatom. ８１ is a fluorine atom or a fluorinated hydrocarbyl group having 1 to 10 carbon atoms, and the fluorinated hydrocarbyl group may contain a hydroxy group, an ether bond, or an ester bond. ８２ is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain a hydroxy group, an ether bond, or an ester bond. ８１ and R ８２ may be bonded to each other to form a ring together with the atoms to which they are attached.

2. The above A １ is an acryloyloxy group, a methacryloyloxy group, a cycloalkenyl group having 3 to 20 carbon atoms which may contain a heteroatom, a cycloalkenyloxy group having 3 to 20 carbon atoms which may contain a heteroatom, a cycloalkenylcarbonyloxy group having 3 to 20 carbon atoms which may contain a heteroatom, an alkenyl group having 2 to 20 carbon atoms which may contain a heteroatom, or an alkenyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, ２ But Ar １Ｂ The molecular resist composition according to claim 1, characterized in that it is a group that, together with the two carbon atoms therein, forms a cycloalkene ring having 4 to 20 carbon atoms which may contain heteroatoms, or a polycycle having 4 to 20 carbon atoms and one double bond which may contain heteroatoms.

3. The X － is the same as the counter anion of the iodonium cation represented by formula (1-1).

4. 2. The molecular resist composition according to claim 1, wherein the anion represented by any one of the formulas (1-2) to (1-8) contains a polymerizable functional group.

5. 2. The molecular resist composition according to claim 1, further comprising a radical scavenger.

6. 2. The molecular resist composition according to claim 1, further comprising a surfactant.

7. A pattern forming method comprising the steps of: forming a resist film on a substrate using the molecular resist composition according to any one of claims 1 to 6; exposing the resist film to high-energy rays; and developing the exposed resist film using a developer.

8. 8. The pattern forming method according to claim 7, wherein an alkaline aqueous solution is used as the developer to dissolve exposed areas and to obtain a positive pattern in which unexposed areas do not dissolve.

9. 8. The pattern forming method according to claim 7, wherein the developer is an organic solvent or an alkaline aqueous solution, which dissolves the unexposed areas and provides a negative pattern in which the exposed areas do not dissolve.

10. Examples of the organic solvent for the developer include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, cyclohexyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, methyl propionate, and propionate.

10. The pattern formation method according to claim 9, wherein at least one selected from the group consisting of ethyl lactate, 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, ethyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, and 2-phenylethyl acetate is used.

11. 8. The pattern formation method according to claim 7, wherein the high-energy beam is an electron beam or extreme ultraviolet light.

Images