Molecular resist composition and pattern forming method

Abstract

The invention relates to a molecular resist composition and a pattern forming method. The present invention addresses the problem of providing: a molecular resist composition having excellent sensitivity, resolution, and LWR in optical lithography using high-energy rays; and a pattern forming method using the molecular resist composition. The present invention is a molecular resist composition characterized by containing a sulfonium salt represented by the following formula (1) or (2), a salt containing a cation represented by the following formula (1-1) and a halide ion, a nitrate ion, a hydrogen sulfate ion, a bicarbonate ion, a tetraphenylborate ion or an anion represented by any one of the following formulae (1-2)-(1-8), and an organic solvent, and no base polymer is contained.

Description

Technical Field

[0001] This invention relates to a molecular resist composition and a method for forming patterns. Background Technology

[0002] As the IoT market expands, there is a growing demand for higher integration, higher speed, and lower power consumption in LSIs, leading to rapid miniaturization of patterning. In particular, logic devices are leading this miniaturization. Regarding state-of-the-art miniaturization technologies, mass production of 10nm node devices using dual, triple, and quadruple patterning with ArF immersion lithography has been achieved, along with research into 7nm node devices using next-generation 13.5nm extreme ultraviolet (EUV) lithography.

[0003] In EUV lithography, chemically amplified resist compositions can be applied to form linewidths of less than 20 nm in line patterns. However, when polymeric resist compositions used in ArF lithography are applied to EUV lithography, the large molecular size of the base polymers results in surface roughness, making pattern control difficult. Therefore, various low-molecular-weight materials have been proposed.

[0004] Molecular resist compositions are resist compositions primarily composed of low-molecular-weight compounds and do not contain the base polymers used in polymer-based resist compositions. Molecular resist compositions are expected to be one of the effective methods for forming fine patterns. For example, a negative radiosensitive resist composition for alkaline development has been proposed, using a polyphenolic compound as the main component (Patent Document 1). Another example is a positive radiosensitive resist composition for alkaline development, which contains only a cationic tert-butoxycarbonyloxy group of a sulfonium salt combined with an anion of a strong acid to form an acid-generating agent (Non-Patent Document 1). Because the aforementioned acid-generating agents have smaller molecular sizes compared to polymeric materials, improved roughness is expected. However, molecular resist compositions using the aforementioned chemical amplification mechanism have not yet achieved satisfactory performance due to the difficulty in controlling acid diffusion. Furthermore, for EUV resist compositions, not only roughness but also high sensitivity and high resolution are required, demanding further improvements.

[0005] One factor contributing to the difficulty in developing materials for EUV lithography is the low photon count during EUV exposure. EUV energy is significantly higher than ArF excimer lasers, and the number of photons in EUV exposure is only one-fourteenth that of ArF exposure. Furthermore, the size of patterns formed by EUV exposure is less than half that of ArF exposure. Therefore, EUV exposure is susceptible to variations in photon count. These variations in photon count in extremely short wavelength emission regions constitute shot noise, a physical phenomenon that cannot be eliminated. Consequently, so-called stochastics have gained attention. While shot noise cannot be eliminated, methods to reduce its impact have been discussed. Due to shot noise, not only do dimensional uniformity (CDU) and linewidth roughness (LWR) increase, but vias have also been observed to become clogged with a probability of one in millions. If vias become clogged, poor conductivity occurs, and transistors malfunction, thus negatively impacting overall device performance.

[0006] Regarding methods to reduce the impact of shot noise in resists, some have proposed inorganic resist compositions with elements that have high EUV absorption as the core (Patent Document 2). However, although inorganic resist compositions have relatively high sensitivity, they are still insufficient and have many problems such as insufficient solubility in resist solvents, storage stability, and other defects.

[0007] Existing technical documents

[0008] Patent documents

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2005-326838

[0010] [Patent Document 2] Japanese Patent Application Publication No. 2015-108781

[0011] Non-patent literature

[0012] [Non-Patent Literature 1] Proc. of SPIE Vol. 6923, 69230K (2008) Summary of the Invention

[0013] [The problem that the invention aims to solve]

[0014] The present invention was made in view of the foregoing circumstances, and its object is to provide a molecular resist composition with excellent sensitivity, resolution and LWR in optical lithography using high-energy rays, and a pattern formation method using the molecular resist composition.

[0015] [Methods for solving the problem]

[0016] To address the aforementioned issues, this invention provides a molecular resist composition characterized by comprising: a sulfonium salt represented by formula (1) or (2), a sulfonium salt containing a sulfonium cation represented by formula (1-1), and an anion represented by a halide ion, nitrate ion, hydrogen sulfate ion, bicarbonate ion, tetraphenylborate ion, or any one of formulas (1-2) to (1-8), and an organic solvent, and without a base polymer;

[0017] [Chemistry 1]

[0018]

[0019] In the formula, n is an integer from 1 to 3; A 1 It is a hydrocarbon group with 2 to 20 carbon atoms containing a polymerizable functional group; this hydrocarbon group may also contain heteroatoms; A 2 It contains polymerizable functional groups and is compatible with Ar 1B Two carbon atoms together form a group with an alicyclic ring having 4 to 20 carbon atoms; this alicyclic ring may also contain heteroatoms; Ar 1A It is an arylene group with 6 to 20 carbon atoms, in which some or all of the hydrogen atoms on the aromatic ring may be replaced by halogen atoms, or by a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; Ar 1B It is a trivalent aromatic hydrocarbon group with 6 to 20 carbon atoms, wherein some or all of the hydrogen atoms on the aromatic ring of the trivalent aromatic hydrocarbon group may be replaced by halogen atoms, or it may contain a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; Ar 2 It is an aryl group with 6 to 20 carbon atoms, in which some or all of the hydrogen atoms on the aromatic ring may be replaced by halogen atoms, or by a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; also, 2 Ar 1A 2 Ar 1B 2 Ar 2 Ar 1A with Ar 2 、or Ar 1B with Ar 2 They can also bond to each other and form rings together with the sulfur atoms they are bonded to; X - It is a relative anion;

[0020] [Chemistry 2]

[0021]

[0022] In the formula, R 31 R 32 Each is an independent halogen atom, or may contain heteroatoms, and is a hydrocarbon group with 1 to 30 carbon atoms;

[0023] [Chemistry 3]

[0024]

[0025] In the formula, k1 and k2 are each independently 1, 2, 3, or 4; Rf 1 and Rf 2 Each is independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms; however, all Rf 1 and Rf 2 It cannot be both a hydrogen atom and a hydrogen atom; R 41 It can be a hydrogen atom, a halogen atom, a hydroxyl group, or a hydrocarbon group with 1 to 50 carbon atoms that may contain heteroatoms; R 42 It is a hydrocarbon group with 1 to 50 carbon atoms, consisting of hydrogen atoms, halogen atoms, hydroxyl groups, or heteroatoms; however, it excludes those in which the hydrogen atoms at the α and β positions of the sulfonate group are replaced by fluorine atoms or fluoroalkyl groups; R 51 It can be a hydrogen atom, a halogen atom, a hydroxyl group, or a hydrocarbon group with 1 to 50 carbon atoms that may contain heteroatoms; R 52 It is a hydrocarbon group with 1 to 50 carbon atoms, consisting of hydrogen atoms, halogen atoms, hydroxyl groups, or heteroatoms; however, it excludes those in which the hydrogen atoms at the α and β positions of the carboxyl group are replaced by fluorine atoms or fluoroalkyl groups; R 61 and R 62 Each can be an independent hydrocarbon group with 1 to 50 carbon atoms, which may also contain heteroatoms; R 71 ~R 73 Each can be an independent hydrocarbon group with 1 to 50 carbon atoms, which may also contain heteroatoms; R 81 It is a fluorine atom or a fluorinated hydrocarbon group having 1 to 10 carbon atoms; the fluorinated hydrocarbon group may also contain a hydroxyl group, an ether bond, or an ester bond; R 82 It consists of a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms; this hydrocarbon group may also contain a hydroxyl group, an ether bond, or an ester bond; furthermore, R 81 With R 82 They can also bond to each other and form rings together with the atoms they are bonded to.

[0026] If the molecular resist composition of the present invention is such, it exhibits excellent sensitivity, resolution, and LWR in optical lithography using high-energy rays, especially electron beam (EB) lithography and EUV lithography.

[0027] In this invention, the aforementioned A 1 Acryloyloxy, methacryloyloxy, or may contain a cycloalkenyl group with 3 to 20 carbon atoms, a cycloalkenyloxy group with 3 to 20 carbon atoms, a cycloalkenylcarbonyloxy group with 3 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms, or an alkenyloxy group with 2 to 20 carbon atoms, as described above A 2 To be with Ar 1BIdeally, the two carbon atoms in the group should be combined to form a cycloalkene ring with 4 to 20 carbon atoms, or a polycyclic group with 4 to 20 carbon atoms and one double bond, which may also contain heteroatoms.

[0028] If A is a hydrocarbon group containing such polymeric functional groups... 1 , and Ar 1B A group containing polymerizable functional groups in which two carbon atoms together form a ring. 2 In this case, polymerization caused by polymerizable functional groups can be used to achieve ideal pattern formation.

[0029] In this invention, the above-mentioned X - Ideally, the relative anion of the ferric cation represented by the aforementioned formula (1-1) should be the same.

[0030] Thus, in the molecular resist composition of the present invention, the anion X of the sulfonium salt represented by formula (1) or (2) above - Ideally, the anion representing the citric acid cation in formula (1-1) should be one with the same structure.

[0031] In this invention, it is preferable that the anion represented by any one of the formulas (1-2) to (1-8) contains a polymerizable functional group.

[0032] In this invention, from the perspective of pattern formation, it is more desirable for the cation of the sulfonium salt represented by formula (1) or (2) above, and the anion represented by any one of formulas (1-2) to (1-8) above, that is, for the relative anion of the ferrophosphate cation represented by formula (1-1) above, to have a polymerizable functional group, and it is even more desirable for the anion of the sulfonium salt above and the anion of the ferrophosphate salt above to have a polymerizable functional group.

[0033] The molecular resist composition of the present invention may also contain a free radical scavenger or a surfactant.

[0034] The molecular resist composition of the present invention can include such components as needed.

[0035] Furthermore, the present invention provides a pattern forming method, characterized by comprising the following steps: forming a resist film on a substrate using the above-described molecular resist composition; exposing the aforementioned resist film to high-energy radiation; and developing the previously exposed resist film using a developing solution.

[0036] If the pattern forming method of the present invention is as described, by using the molecular resist composition of the present invention and forming a resist film on a substrate, it is possible to form patterns with excellent sensitivity, resolution and LWR in optical lithography using high-energy rays, especially electron beam (EB) lithography and EUV lithography.

[0037] At this point, not only can an alkaline aqueous solution be used as the above-mentioned developer to dissolve the exposed portion and obtain a positive pattern in which the unexposed portion does not dissolve, but an organic solvent or an alkaline aqueous solution can also be used as the above-mentioned developer to dissolve the unexposed portion and obtain a negative pattern in which the exposed portion does not dissolve.

[0038] Thus, when using the molecular resist composition of the present invention, positive and negative patterns can also be obtained by combining it with a suitable developer.

[0039] In this invention, the organic solvent used in the aforementioned developing solution is selected from 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methyl acetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butyl acetate, isoamyl acetate, cyclohexyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl valerate, methyl crotonate, etc. At least one of the following is preferred: ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenyl acetate, ethyl phenyl acetate, benzyl formate, phenyl ethyl formate, methyl 3-phenylpropionate, benzyl propionate, and 2-phenylethyl acetate.

[0040] When using the molecular resist composition of the present invention and developing with an organic solvent to obtain a negative pattern, the organic solvent described above can be ideally used.

[0041] Furthermore, in this invention, electron beams or extreme ultraviolet light can be used as the aforementioned high-energy rays.

[0042] The molecular resist composition of the present invention exhibits excellent sensitivity, resolution, and LWR, particularly in EB and EUV lithography, thus enabling the formation of fine patterns that meet the requirements of pattern regularity.

[0043] [The effects of the invention]

[0044] As described above, the molecular resist composition of the present invention is very useful in forming fine patterns because it combines high sensitivity and high resolution in optical lithography using high-energy rays, especially EB lithography and EUV lithography, and has excellent LWR. Attached Figure Description

[0045] [ Figure 1 The PAG-1 obtained in Synthesis Example 1-1 1 H-NMR spectrum.

[0046] [ Figure 2 The PAG-2 obtained in Synthesis Example 1-2 1 H-NMR spectrum.

[0047] [ Figure 3 The PAG-3 obtained in Synthetic Examples 1-3 1 H-NMR spectrum.

[0048] [ Figure 4 The PAG-4 obtained in Synthetic Examples 1-4 1 H-NMR spectrum.

[0049] [ Figure 5 The PAG-5 obtained in Synthetic Examples 1-5 1 H-NMR spectrum.

[0050] [ Figure 6 The PAG-6 obtained in Synthetic Examples 1-6 1 H-NMR spectrum.

[0051] [ Figure 7 The PAG-7 obtained in Synthetic Examples 1-7 1 H-NMR spectrum.

[0052] [ Figure 8 The PAG-8 obtained in Synthetic Examples 1-8 1 H-NMR spectrum.

[0053] [ Figure 9 The PAG-9 obtained in Synthetic Examples 1-9 1 H-NMR spectrum. Detailed Implementation

[0054] In order to achieve the aforementioned objective, the inventors conducted repeated and careful research and found that molecular resist compositions containing sulfonium salts and ferrous salts with specific partial structures provide resist films with high sensitivity, excellent resolution, and low WR, which are extremely effective for precision micro-machining, thus leading to the completion of this invention.

[0055] That is, the present invention is a molecular resist composition, characterized in that: it contains a sulfonium salt represented by formula (1) or (2), a sulfonium cation represented by formula (1-1), and an anion represented by a halide ion, nitrate ion, hydrogen sulfate ion, bicarbonate ion, tetraphenylborate ion or any of the following formulas (1-2) to (1-8), and an organic solvent, and does not contain a base polymer;

[0056] [Chemistry 4]

[0057]

[0058] In the formula, n is an integer from 1 to 3; A 1 It is a hydrocarbon group with 2 to 20 carbon atoms containing a polymerizable functional group; this hydrocarbon group may also contain heteroatoms; A 2 It contains polymerizable functional groups and is compatible with Ar 1B Two carbon atoms together form a group with an alicyclic ring having 4 to 20 carbon atoms; this alicyclic ring may also contain heteroatoms; Ar 1A It is an arylene group with 6 to 20 carbon atoms, in which some or all of the hydrogen atoms on the aromatic ring may be replaced by halogen atoms, or by a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; Ar 1B It is a trivalent aromatic hydrocarbon group with 6 to 20 carbon atoms, wherein some or all of the hydrogen atoms on the aromatic ring of the trivalent aromatic hydrocarbon group may be replaced by halogen atoms, or it may contain a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; Ar 2 It is an aryl group with 6 to 20 carbon atoms, in which some or all of the hydrogen atoms on the aromatic ring may be replaced by halogen atoms, or by a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; also, 2 Ar 1A 2 Ar 1B 2 Ar 2 Ar 1A with Ar 2 、or Ar 1B with Ar 2 They can also bond to each other and form rings together with the sulfur atoms they are bonded to; X - It is a relative anion;

[0059] [Chemistry 5]

[0060]

[0061] In the formula, R 31 R 32 Each is an independent halogen atom, or may contain heteroatoms, and is a hydrocarbon group with 1 to 30 carbon atoms;

[0062] [Chemistry 6]

[0063]

[0064] In the formula, k1 and k2 are each independently 1, 2, 3, or 4; Rf 1 and Rf 2 Each is independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms; however, all Rf 1 and Rf 2 It cannot be both a hydrogen atom and a hydrogen atom; R 41 It can be a hydrogen atom, a halogen atom, a hydroxyl group, or a hydrocarbon group with 1 to 50 carbon atoms that may contain heteroatoms; R 42It is a hydrocarbon group with 1 to 50 carbon atoms, consisting of hydrogen atoms, halogen atoms, hydroxyl groups, or heteroatoms; however, it excludes those in which the hydrogen atoms at the α and β positions of the sulfonate group are replaced by fluorine atoms or fluoroalkyl groups; R 51 It can be a hydrogen atom, a halogen atom, a hydroxyl group, or a hydrocarbon group with 1 to 50 carbon atoms that may contain heteroatoms; R 52 It is a hydrocarbon group with 1 to 50 carbon atoms, consisting of hydrogen atoms, halogen atoms, hydroxyl groups, or heteroatoms; however, it excludes those in which the hydrogen atoms at the α and β positions of the carboxyl group are replaced by fluorine atoms or fluoroalkyl groups; R 61 and R 62 Each can be an independent hydrocarbon group with 1 to 50 carbon atoms, which may also contain heteroatoms; R 71 ~R 73 Each can be an independent hydrocarbon group with 1 to 50 carbon atoms, which may also contain heteroatoms; R 81 It is a fluorine atom or a fluorinated hydrocarbon group having 1 to 10 carbon atoms; the fluorinated hydrocarbon group may also contain a hydroxyl group, an ether bond, or an ester bond; R 82 It consists of a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms; this hydrocarbon group may also contain a hydroxyl group, an ether bond, or an ester bond; furthermore, R 81 With R 82 They can also bond to each other and form rings together with the atoms they are bonded to.

[0065] The present invention will now be described in detail, but it is not limited thereto. Furthermore, in this specification, a description of a numerical range's endpoints is defined as including all values ​​contained within that range.

[0066] [Molecular corrosion inhibitor]

[0067] The molecular resist composition of the present invention comprises (i) a sulfonium salt represented by formula (1) or (2) above, (ii) a sulfonium cation represented by formula (1-1) above, and halide ions and nitrate ions (NO3). - ), hydrogen sulfate ions (HSO4) - ), bicarbonate ions (HCO3) - ), tetraphenylborate ion (BPh4) - (iii) An anionic salt represented by any of the following formulas (1-2) to (1-8), and an organic solvent, and without (iv) a base polymer. Furthermore, in the molecular resist composition of the present invention, the main component refers to the component other than the solvent that is present in the largest quantity.

[0068] The molecular resist composition of the present invention uses the above-mentioned sulfonium salt, which is a monomolecular compound, as the main component and combines it with the above-mentioned photodegradable sulfonium salt. Even without the basic polymer used in polymeric resist compositions, the above-mentioned sulfonium salt, which has polymerizable functional groups, will polymerize, thereby effectively increasing the molecular weight and still forming patterns with improved contrast, sensitivity, and resolution.

[0069] The aforementioned matte salts, due to their smaller molecular size compared to polymer materials, contribute to improved surface roughness. Furthermore, the addition of these matte salts enhances EUV light absorption and further improves the resist's properties, sensitivity, and surface roughness.

[0070] The following describes the components contained in the molecular resist composition of the present invention.

[0071] [Sulfate]

[0072] The molecular resist composition of the present invention comprises a sulfonium salt represented by formula (1) or (2) as the main component.

[0073] [Chemistry 7]

[0074]

[0075] In the above formula, n is an integer from 1 to 3.

[0076] A 1 It is a hydrocarbon group with 2 to 20 carbon atoms containing polymerizable functional groups, and the hydrocarbon group may also contain heteroatoms.

[0077] A 2 It contains polymerizable functional groups and is compatible with Ar 1B Two carbon atoms together form a group of alicyclic rings with 4 to 20 carbon atoms, which may also contain heteroatoms.

[0078] Ar 1A It is an arylene with 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the arylene may be replaced by halogen atoms or hydrocarbon groups with 1 to 20 carbon atoms containing heteroatoms.

[0079] Ar 1B It is a trivalent aromatic hydrocarbon group with 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 replaced by halogen atoms, or it may be a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms.

[0080] Ar 2 It is an aryl group with 6 to 20 carbon atoms, and some or all of the hydrogen atoms on the aromatic ring of the aryl group may be replaced by halogen atoms, or it may contain a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms.

[0081] Also, 2 Ar 1A 2 Ar 1B 2 Ar 2 Ar 1A with Ar 2 、or Ar 1B with Ar 2They can also bond to each other and form rings together with the sulfur atoms they are bonded to.

[0082] X - It is a relative anion.

[0083] The above A 1 A 2 The polymerizable functional groups it contains are free radical polymerizable.

[0084] In equations (1) and (2), n is an integer from 1 to 3.

[0085] In equation (1), A 1 It is a hydrocarbon group with 2 to 20 carbon atoms containing a polymerizable functional group, and this hydrocarbon group may also contain heteroatoms. In formula (2), A 2 It contains polymerizable functional groups and is compatible with Ar 1B Two carbon atoms together form a group of alicyclic rings with 4 to 20 carbon atoms, which may also contain heteroatoms. Examples of heteroatoms include oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms.

[0086] Regarding A 1 For example, acryloyloxy, methacryloxy, or a cycloalkenyl group with 3 to 20 carbon atoms containing heteroatoms, a cycloalkenyloxy group with 3 to 20 carbon atoms containing heteroatoms, a cycloalkenylcarbonyloxy group with 3 to 20 carbon atoms containing heteroatoms, an alkenyl group with 2 to 20 carbon atoms containing heteroatoms, or an alkenyloxy group with 2 to 20 carbon atoms containing heteroatoms are preferred. Regarding A... 2 In terms of Ar 1B It is preferable that the two carbon atoms in the group together form a cycloalkene ring with 4 to 20 carbon atoms, or a polycyclic group with 4 to 20 carbon atoms and one double bond, which may also contain heteroatoms.

[0087] Regarding A 1 Specific examples of the groups represented include, but are not limited to, the groups shown below. Furthermore, in the following formula, the dashed line indicates groups related to Ar. 1A Atomic bonds.

[0088] [Chemistry 8]

[0089]

[0090] [Chemistry 9]

[0091]

[0092] [Chemistry 10]

[0093]

[0094] [Chemistry 11]

[0095]

[0096] Regarding A 2 To be with Ar 1B Specific examples of alicyclic rings with 4 to 20 carbon atoms formed by two carbon atoms together include, but are not limited to, those shown below. Furthermore, in the following formula, "C" represents Ar. 1B The carbon atoms contained in it.

[0097] [Chemistry 12]

[0098]

[0099] Among these, considering the ease of introduction and polymerization reactivity in the synthesis process, A-1~A-18, A-30~A-43, and A-57 are more ideal, while A-9~A-18, A-30~A-35, and A-40 are even more ideal.

[0100] In equation (1), Ar 1A It is an arylene group with 6 to 20 carbon atoms. Examples of arylenes include phenylene, naphthylene, and anthracenediyl. In formula (2), Ar... 1B It is a trivalent aromatic hydrocarbon group with 6 to 20 carbon atoms. Examples of trivalent aromatic hydrocarbon groups include those obtained by removing three hydrogen atoms from benzene, naphthalene, and anthracene. In formulas (1) and (2), Ar... 2 Aryl groups are those with 6 to 20 carbon atoms. Examples of aryl groups include phenyl, naphthyl, and anthracene. Among these, considering solvent solubility, Ar... 1A In this regard, phenylene or naphthylene is more ideal, with phenylene being even more ideal, as for Ar 1B In terms of Ar, phenyltriyl or naphthyltriyl is more ideal, with phenyltriyl being even more ideal. 2 In this regard, phenyl or naphthyl are more ideal, with phenyl being even more ideal.

[0101] The hydrogen atoms of the aforementioned aryl, trivalent aromatic hydrocarbon groups, and aryl groups may be partially or completely replaced by halogen atoms, or by hydrocarbon groups with 1 to 20 carbon atoms containing heteroatoms. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms. Hydrocarbon groups with 1 to 20 carbon atoms may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkyl groups with 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, norcamphenyl, and tricyclic [5.2.1.0] 2,6Cyclic saturated hydrocarbon groups with 3 to 20 carbon atoms, such as decyl, adamantyl, and adamantylmethyl; aryl groups with 6 to 20 carbon atoms, such as phenyl, naphthyl, and anthracene. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon groups can be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms. Similarly, a portion of the -CH2- group constituting the aforementioned hydrocarbon group can be replaced by groups containing heteroatoms such as oxygen, sulfur, and nitrogen atoms. As a result, the hydrocarbon groups may contain hydroxyl, cyano, halogen, carbonyl, ether, thioether, ester, sulfonate, carbonate, carbamate, lactone ring, sulfonyl lactone ring, carboxylic anhydride (-C(=O)-OC(=O)-), etc.

[0102] Furthermore, given their existence, 2 Ar 1A 2 Ar 1B 2 Ar 2 Ar 1A with Ar 2 、or Ar 1B with Ar 2 They can also bond to each other and form rings together with the sulfur atoms to which they are bonded. In this case, the structures of the aforementioned rings can be listed below, but are not limited to these.

[0103] [Chemistry 13]

[0104]

[0105] In the formula, the dashed lines represent atomic bonds.

[0106] Specific examples of the cations of the sulfonium salt represented by formula (1) can be listed below, but are not limited to these.

[0107] [Chemistry 14]

[0108]

[0109] [Chemistry 15]

[0110]

[0111] [Chemistry 16]

[0112]

[0113] [Chemistry 17]

[0114]

[0115] [Chemistry 18]

[0116]

[0117] [Chemistry 19]

[0118]

[0119] [Chemistry 20]

[0120]

[0121] [Chemistry 21]

[0122]

[0123] [Chemistry 22]

[0124]

[0125] [Chemistry 23]

[0126]

[0127] [Chemistry 24]

[0128]

[0129] [Chemistry 25]

[0130]

[0131] [Chemistry 26]

[0132]

[0133] [Chemistry 27]

[0134]

[0135] [Chemistry 28]

[0136]

[0137] Specific examples of the cations of the sulfonium salt represented by formula (2) can be listed below, but are not limited to these.

[0138] [Chemistry 29]

[0139]

[0140] In equations (1) and (2), X - The relative anion is not particularly limited and can be a non-nucleophilic anion. For the aforementioned relative anion, the anion represented by halide ion, nitrate ion, hydrogen sulfate ion, bicarbonate ion, tetraphenylborate ion or any of the following formulas (1-2) to (1-8) is more ideal.

[0141] [Chemistry 30]

[0142]

[0143] In equations (1-2) and (1-4), k1 and k2 are each independent integers from 1 to 4 (1, 2, 3, or 4). Rf 1 and Rf 2 Each is independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms; however, all Rf 1 and Rf 2 It cannot be both hydrogen atoms at the same time.

[0144] In equation (1-2), R 41 It is a hydrocarbon group with 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, consisting of hydrogen atoms, halogen atoms, hydroxyl groups, or heteroatoms.

[0145] In equation (1-3), R 42 It is a hydrocarbon group with 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, containing hydrogen atoms, halogen atoms, hydroxyl groups, or heteroatoms. However, it excludes those in which the hydrogen atoms at the α and β positions of the sulfonate group are replaced by fluorine atoms or fluoroalkyl groups.

[0146] In equation (1-4), R 51 It is a hydrocarbon group with 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, consisting of hydrogen atoms, halogen atoms, hydroxyl groups, or heteroatoms.

[0147] In equation (1-5), R 52 It is a hydrocarbon group with 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, containing hydrogen atoms, halogen atoms, hydroxyl groups, or heteroatoms. However, it is excluded if the hydrogen atoms on the carbon atoms at the α and β positions of the carboxyl group are replaced by fluorine atoms or fluoroalkyl groups.

[0148] In equation (1-6), R 61 and R 62 Each can be an independent hydrocarbon group containing heteroatoms with 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms.

[0149] In equation (1-7), R 71 ~R 73 Each can be an independent hydrocarbon group containing heteroatoms with 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms.

[0150] In equation (1-8), R 81 It is a fluorine atom or a fluorinated hydrocarbon group having 1 to 10 carbon atoms; the fluorinated hydrocarbon group may also contain a hydroxyl group, an ether bond, or an ester bond. R 82 It consists of a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms; this hydrocarbon group may also contain a hydroxyl group, an ether bond, or an ester bond. Also, R 81 With R 82 They can also bond to each other and form rings together with the atoms they are bonded to.

[0151] Regarding X- Of the anions represented, the anions represented by halide ions, nitrate ions, or any of the formulas (1-2) to (1-8) are more ideal, and the anions represented by halide ions, nitrate ions, or formulas (1-3), (1-5), or (1-7) are even more ideal.

[0152] R 41 R 42 R 51 R 52 R 61 R 62 R 71 R 72 and R 73 The hydrocarbon group represented has 1 to 50 carbon atoms and can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include alkyl groups with 1 to 50 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, norcamphenyl, and tricyclic [5.2.1.0]. 2,6 ] Decyl, adamantyl, adamantylmethyl, and other cyclic saturated hydrocarbon groups with 3 to 50 carbon atoms; phenyl, naphthyl, anthracene, and other aryl groups with 6 to 50 carbon atoms; and groups obtained by combining these. Furthermore, some or all of the hydrogen atoms of the aforementioned hydrocarbon groups may be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of the -CH2- constituting the aforementioned hydrocarbon groups may also be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, hydroxyl, cyano, halogen, carbonyl, ether bond, thioether bond, ester bond, sulfonate bond, carbonate bond, carbamate bond, lactone ring, sulopenicone ring, carboxylic anhydride (-C(=O)-OC(=O)-), etc.

[0153] R 81 The fluorinated hydrocarbon group representing 1 to 10 carbon atoms is a group in which some or all of the hydrogen atoms of a hydrocarbon group with 1 to 10 carbon atoms are replaced by fluorine atoms. The aforementioned hydrocarbon group with 1 to 10 carbon atoms can be saturated or unsaturated, and can be linear, branched, or cyclic. For specific examples, examples already exemplified as R... 41 R 42 R 51 R 52 R 61 R 62 R 71 R 72 and R 73 The hydrocarbon group representing 1 to 50 carbon atoms has 1 to 10 carbon atoms.

[0154] R 82 The hydrocarbon group representing 1 to 20 carbon atoms can be saturated or unsaturated, and can be linear, branched, or cyclic. For specific examples, examples already exemplified as R... 41 R 42 R 51 R 52 R 61 R 62 R 71 R 72 and R 73 The hydrocarbon group representing 1 to 50 carbon atoms has 1 to 20 carbon atoms.

[0155] The anion represented by any of formulas (1-2) to (1-8) is preferably one containing a polymerizable functional group, or it may contain a polymerizable functional group in its structure and have a hydrocarbon group with 2 to 20 carbon atoms, which may also contain heteroatoms. For specific examples, A, as exemplified in formula (1), can be listed. 1 The group indicated is the same as that of the group.

[0156] Regarding the anions represented by formula (1-2), the following examples can be listed, but are not limited to these. Furthermore, in the following formula, Ac represents an acetyl group, and Rf... 1 Same as above.

[0157] [Chemistry 31]

[0158]

[0159] [Chemistry 32]

[0160]

[0161] [Chemistry 33]

[0162]

[0163] [Chemistry 34]

[0164]

[0165] [Chemistry 35]

[0166]

[0167] [Chemistry 36]

[0168]

[0169] [Chemistry 37]

[0170]

[0171] [Chemistry 38]

[0172]

[0173] [Chemistry 39]

[0174]

[0175] [Chemistry 40]

[0176]

[0177] [Chemistry 41]

[0178]

[0179] [Chemistry 42]

[0180]

[0181] [Chemistry 43]

[0182]

[0183] Regarding the anions represented by equations (1-3), the following examples can be listed, but are not limited to these.

[0184] [Chemistry 44]

[0185]

[0186] [Chemistry 45]

[0187]

[0188] [Chemistry 46]

[0189]

[0190] [Chemistry 47]

[0191]

[0192] [Chemistry 48]

[0193]

[0194] [Chemistry 49]

[0195]

[0196] Regarding the anions represented by equations (1-4), the following examples can be listed, but are not limited to these.

[0197] [Transformation 50]

[0198]

[0199] [Chemistry 51]

[0200]

[0201] Regarding the anions represented by equations (1-5), the following examples can be listed, but are not limited to these.

[0202] [Chemistry 52]

[0203]

[0204] [Chemistry 53]

[0205]

[0206] [Chemistry 54]

[0207]

[0208] Regarding the anions represented by equations (1-6), the following examples can be listed, but are not limited to these.

[0209] [Chemistry 55]

[0210]

[0211] [Chemistry 56]

[0212]

[0213] Regarding the anions represented by equations (1-7), the following examples can be listed, but are not limited to these.

[0214] [Chemistry 57]

[0215]

[0216] [Chem.58]

[0217]

[0218] [Chemistry 59]

[0219]

[0220] Regarding the anions represented by equations (1-8), the following examples can be listed, but are not limited to these.

[0221] [Transformation 60]

[0222]

[0223] [Chemistry 61]

[0224]

[0225] Regarding specific examples of sulfonium salts represented by formula (1) or (2), any combination of the aforementioned specific examples of anions and specific examples of cations can be listed.

[0226] Regarding the sulfonium salt represented by formula (1) or (2), from the perspective of pattern formation, it is more ideal for the cation and anion that form the salt to have polymerizable functional groups.

[0227] The sulfonium salt represented by formula (1) or (2) can be used alone or in combination with more than two. Considering the point of view of improving the uniformity of the composition, it is more ideal to use one alone or in combination with two.

[0228] The sulfonium salt represented by formula (1) or (2) can be synthesized by combining known organic chemical methods. For example, a method can be listed by mixing onium salt intermediates having desired cations and anions and carrying out an ion exchange reaction. Furthermore, the ion exchange reaction can be easily achieved using known methods, for example, Japanese Patent Application Publication No. 2007-145797.

[0229] [Fermented Salt]

[0230] The molecular resist composition of the present invention comprises a ferric salt containing a ferric cation represented by formula (1-1) and a halide ion, nitrate ion, hydrogen sulfate ion, bicarbonate ion, tetraphenylborate ion or an anion represented by any of formulas (1-2) to (1-8).

[0231] [Chemistry 62]

[0232]

[0233] In the formula, R 31 R 32 Each is an independent hydrocarbon group consisting of halogen atoms or may contain heteroatoms, and has 1 to 30 carbon atoms.

[0234] [Chemistry 63]

[0235]

[0236] In the formula, k1 and k2 are each independently 1, 2, 3, or 4. Rf 1 and Rf 2 Each is independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms; however, all Rf 1 and Rf 2 It cannot be both a hydrogen atom and a hydrogen atom. R 41 It is a hydrocarbon group consisting of 1 to 50 carbon atoms, a hydrogen atom, a halogen atom, a hydroxyl group, or a heteroatom. R 42It is a hydrocarbon group with 1 to 50 carbon atoms, consisting of a hydrogen atom, a halogen atom, a hydroxyl group, or possibly a heteroatom. However, it excludes those where the hydrogen atoms at the α and β positions of the sulfonate group are replaced by fluorine atoms or fluoroalkyl groups. R 51 It is a hydrocarbon group consisting of 1 to 50 carbon atoms, a hydrogen atom, a halogen atom, a hydroxyl group, or a heteroatom. R 52 It is a hydrocarbon group with 1 to 50 carbon atoms, consisting of a hydrogen atom, a halogen atom, a hydroxyl group, or possibly a heteroatom. However, it excludes those where the hydrogen atoms at the α and β positions of the carboxyl group are replaced by fluorine atoms or fluoroalkyl groups. R 61 and R 62 Each can be an independent hydrocarbon group with 1 to 50 carbon atoms, and may also contain heteroatoms. R 71 ~R 73 Each can be an independent hydrocarbon group with 1 to 50 carbon atoms, and may also contain heteroatoms. R 81 It is a fluorine atom or a fluorinated hydrocarbon group having 1 to 10 carbon atoms; the fluorinated hydrocarbon group may also contain a hydroxyl group, an ether bond, or an ester bond. R 82 It consists of a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms; this hydrocarbon group may also contain a hydroxyl group, an ether bond, or an ester bond. Also, R 81 With R 82 They can also bond to each other and form rings together with the atoms they are bonded to.

[0237] In equation (1-1) above, R 31 R 32 Examples of halogen atoms that can be represented include fluorine, chlorine, bromine, and iodine atoms. R 31 R 32 The hydrocarbon group represented by carbon atoms from 1 to 30 can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include alkyl groups with carbon atoms from 1 to 30, 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, norcamphenyl, tricyclic [5.2.1.0] 2,6 Cyclic saturated hydrocarbon groups with 3 to 30 carbon atoms, such as decyl, adamantyl, and adamantylmethyl; aryl groups with 6 to 30 carbon atoms, such as phenyl, naphthyl, and anthracene. Furthermore, some or all of the hydrogen atoms in the aforementioned hydrocarbon groups may be replaced by groups containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms. Similarly, a portion of the -CH2- group in the aforementioned hydrocarbon groups may be replaced by groups containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, groups such as hydroxyl, cyano, halogen, carbonyl, ether, thioether, ester, sulfonate, carbonate, carbamate, lactone ring, sulopentalide ring, and carboxylic anhydride (-C(=O)-OC(=O)-) may also be present.

[0238] Furthermore, X in equation (1) or (2) above - Alternatively, the relative anion of the sulfonium cation represented by the aforementioned formula (1-1) can be the same, that is, the anion X of the above-mentioned sulfonium salt is the same. - The anion corresponding to the aforementioned citric acid cation can also be represented by the same structure. In addition, it can be an anion containing polymeric functional groups independently, or an anion containing polymeric functional groups in addition to the aforementioned formulas (1-2) to (1-8).

[0239] Regarding specific examples of the groups represented by formula (1-1) above, the following groups can be listed, but are not limited to these. Furthermore, the anions represented by any of formulas (1-2) to (1-8) are the same as those for sulfonium salts.

[0240] [Chemistry 64]

[0241]

[0242] [Chemistry 65]

[0243]

[0244] The content of ferrous salt is preferably 1 to 100 parts by weight relative to 100 parts by weight of the above-mentioned matte salt, and even more preferably 5 to 15 parts by weight. Ferrous salt can be used alone or in combination with two or more types.

[0245] The molecular resist composition of the present invention is characterized by the addition of ferrous salt in addition to sulfonium salt, which is the main component. As described later, by adding ferrous salt, the absorption of EUV light is increased, and the resist's probability density, sensitivity, and roughness are improved. Furthermore, ferrous salt has a high EUV light absorption rate, and its photodecomposition efficiently generates free radicals. The resulting free radicals initiate the free radical polymerization of the polymerizable substituents of the sulfonium salt, effectively increasing the molecular weight and thus improving the resist's contrast, sensitivity, and resolution.

[0246] [Organic solvents]

[0247] The molecular resist composition of the present invention contains an organic solvent. As for the aforementioned solvent, there is no particular limitation as to whether it is a sulfonium salt represented by formula (1) or (2) or a sulfonium salt represented by formula (1-1) that can be dissolved and formed into 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 monotert-butyl ether acetate; and lactones such as γ-butyrolactone.

[0248] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, DAA, γ-butyrolactone, and their mixed solvents are more ideal.

[0249] In the molecular resist composition of the present invention, the content of the aforementioned organic solvent is preferably 200 to 5,000 parts by mass relative to 100 parts by mass of the sulfonium salt represented by formula (1) or (2). The aforementioned organic solvent may be used alone or in combination of two or more.

[0250] The molecular resist composition of the present invention is characterized by comprising a sulfonium salt represented by formula (1) or (2), a sulfonium salt represented by formula (1-1), and an organic solvent, which are the main components, and does not contain a base polymer. The resist film obtained from the molecular resist composition of the present invention can be exposed by EB or EUV, and the exposed portion becomes insoluble in alkaline developer, forming a negative pattern. Furthermore, the base polymer is the main component of the polymeric resist composition, and refers to a polymer whose solubility in the developer changes due to the action of acid generated from the acid-generating agent.

[0251] Traditional resist compositions, primarily composed of multi-component polymers (base polymers) and including photoacid generators and sensitivity modifiers, suffer from difficulties in uniformly distributing their components within the resist film. This is particularly problematic in the formation of fine patterns using EUV lithography, significantly impacting surface roughness. Furthermore, the relatively large molecular size of the polymer also contributes to the problem, resulting in deterioration of the resist's flux ratio (LWR) and chromatic diffusivity (CDU).

[0252] In contrast, the molecular resist composition of the present invention has a very simple structure because it does not contain multi-component polymer components, thus improving the uniformity of the composition in the resist film. Furthermore, since the main component is a low-molecular-weight compound, the molecular size is small, which improves LWR and CDU, especially when forming fine patterns using EB lithography and EUV lithography.

[0253] The molecular resist composition of the present invention can be patterned by structural changes caused by the photoreaction of the sulfonium salt, which is the main component, and by polymerization caused by polymerizable functional groups. In this case, by using the sulfonium salt represented by formula (1) or (2), especially in EB lithography and EUV lithography, the photodecomposition of the sulfonium salt and the free radical polymerization of polymerizable groups from free radicals generated during exposure occur, resulting in a significant change in solubility in alkaline developer (insolubility), thus enabling the formation of negative patterns. In particular, if a polymerizable functional group is used in either the cation or anion that forms the sulfonium salt, all the components of the salt during free radical polymerization during exposure contribute to pattern formation, effectively improving the dissolution contrast between the exposed and unexposed areas. Because the structural change occurs during exposure, acid diffusion, as seen with conventional polymer-based chemically amplified resist compositions, does not occur; that is, image blurring caused by acid diffusion does not occur. The molecular resist composition of the present invention has superior resolution compared to conventional polymer-based chemically amplified resist compositions with polymers as the main component, and is also resistant to pattern collapse, thus being extremely effective for the formation of fine patterns.

[0254] The molecular resist composition of the present invention is characterized by the addition of ferrous salt in addition to sulfonium salt, which is the main component. By adding ferrous salt, the absorption of EUV light is enhanced, and the stochastics, sensitivity, and roughness of the resist are improved. Furthermore, the free radicals generated during the photodecomposition of the highly absorbent ferrous salt under EUV light induce free radical polymerization of the polymerizable substituents of the sulfonium salt, effectively increasing the molecular weight and contributing to the improvement of the resist's contrast, sensitivity, and resolution.

[0255] Furthermore, the molecular resist composition of the present invention does not contain polymer components that function as a base polymer, but may, for example, contain polymer components used as additives (i.e., non-main components) such as polymers used as surfactants for patterning of sulfonium salts represented by the aforementioned formula (1) or (2) as needed.

[0256] [Other ingredients]

[0257] The molecular resist composition of the present invention may also include free radical scavengers as other components. By adding free radical scavengers, the photoresponse in optical lithography can be controlled, and the sensitivity can be adjusted.

[0258] Examples of free radical scavengers include hindered phenols, quinones, hindered amines, and thiols. Specifically, examples of hindered phenols include butylated hydroxytoluene (BHT) and 2,2'-methylenebis(4-methyl-6-tert-butylphenol). Examples of quinones include 4-methoxyphenol (p-methoxyphenol) 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 dodecyl mercaptan, hexadecyl mercaptan, and benzene mercaptan. When the molecular resist composition of the present invention contains the aforementioned free radical scavengers, their content is preferably 0.1 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight, relative to 100 parts by weight of the aforementioned sulfonium salt. The aforementioned free radical scavengers can be used alone or in combination of two or more.

[0259] The molecular resist composition of the present invention may also include surfactants as other components. Examples of such surfactants include FC-4432, FC-4430 (manufactured by 3M), PF636, PF656, PF6320, and PF6520 (manufactured by OMNOVA). When the molecular resist composition of the present invention includes a surfactant, its content is preferably 0.001 to 20 parts by weight, and more preferably 0.1 to 10 parts by weight, relative to 100 parts by weight of the aforementioned matte salt. One of the aforementioned surfactants may be used alone, or two or more may be used in combination.

[0260] [Pattern Formation Method]

[0261] When the molecular resist composition of the present invention is used in the manufacture of various integrated circuits, known photolithography techniques can be applied. For example, in terms of pattern formation methods, methods including the following steps can be listed: using the aforementioned molecular resist composition to form a resist film on a substrate; exposing the aforementioned resist film to high-energy rays; and developing the aforementioned exposed resist film using a developer.

[0262] First, the molecular resist composition of the present invention is coated onto an integrated circuit manufacturing substrate (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflective film, etc.) or a mask circuit manufacturing substrate (Cr, CrO, CrON, MoSi2, SiO2, etc.) using appropriate coating methods such as spin coating, roll coating, flow coating, dip coating, spray coating, or blade coating, with a coating thickness of 0.01 to 2 μm. The resist film is then pre-baked on a hot plate at a temperature preferably 60 to 150°C for 10 seconds to 30 minutes, and more preferably 80 to 120°C for 30 seconds to 20 minutes to form a resist film.

[0263] Next, the aforementioned photoresist film is exposed using high-energy radiation. Examples of such high-energy radiation include ultraviolet light, far-ultraviolet light, EB, EUV, X-rays, soft X-rays, excimer lasers, gamma rays, and synchrotron radiation. When using ultraviolet light, far-ultraviolet light, EUV, X-rays, soft X-rays, excimer lasers, gamma rays, or synchrotron radiation as the aforementioned high-energy radiation, a mask for forming the desired pattern is used directly or indirectly, with an exposure dose preferably between 1 and 200 mJ / cm². 2 Left and right, preferably 10-100 mJ / cm 2 Irradiation is performed in a left-right manner. When using EB as a high-energy ray, it is done directly or using a mask to form the desired pattern, with an exposure dose preferably of 0.1–100 μC / cm. 2 The optimal range is 0.5–50 μC / cm. 2 The image is depicted from left to right. Furthermore, the molecular resist composition of the present invention is suitable for fine patterning by KrF excimer lasers, ArF excimer lasers, EB, EUV, X-rays, soft X-rays, gamma rays, and synchrotron radiation, especially by EB or EUV.

[0264] Since the molecular resist composition of the present invention forms an image through a structural change in the aforementioned matte salt during exposure, it is not necessarily required to perform post-exposure baking (PEB) as required for chemically amplified resist compositions. In the case of PEB, it is preferable to perform the baking on a heated plate or in an oven at a temperature of 30–120°C for 10 seconds to 30 minutes, more preferably 60–100°C for 30 seconds to 20 minutes after exposure.

[0265] When the molecular resist composition of the present invention is negative, the portion exposed to light is insoluble in the developer, while the unexposed portion dissolves. On the other hand, when it is positive, the portion exposed to light dissolves in the developer, while the unexposed portion remains insoluble.

[0266] The matte salt contained in the molecular resist composition of the present invention undergoes free radical polymerization by exposure, thereby forming a pattern. However, when the polymer is insoluble in alkaline or organic solvent developing solutions described later, but the unreacted matte salt is soluble, a negative pattern can be formed.

[0267] After exposure or PEB, use a developer solution containing 0.1-10% by mass, preferably 2-5% by mass, of an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), or tetrabutylammonium hydroxide (TBAH), and develop the exposed resist film for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, using conventional methods such as dip, immersion, or spraying to form the desired pattern.

[0268] After development with an alkaline developer, the pattern is rinsed with pure water and then dried by spin drying. To reduce the stress applied to the pattern during drying and prevent pattern collapse, it is also effective to use a rinsing solution containing surfactants or to use supercritical rinsing with carbon dioxide, etc.

[0269] The molecular resist composition of the present invention can also be developed using organic solvents to obtain negative patterns. Examples of developers used include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methyl acetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butenyl acetate, isoamyl acetate, cyclohexyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl valerate, methyl crotonate. Ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, ethyl formate, phenyl ethyl formate, methyl 3-phenylpropionate, benzyl propionate, 2-phenylethyl acetate, etc. These organic solvents can be used alone or in combination of two or more.

[0270] After development, rinsing is performed as needed. Ideally, the rinsing solution should be miscible with the developer but not dissolve the resist film. Suitable solvents include alcohols with 3-10 carbon atoms, ethers with 8-12 carbon atoms, alkanes with 6-12 carbon atoms, alkenes, alkynes, and aromatic solvents.

[0271] Specifically, for alcohols with 3 to 10 carbon atoms, examples include n-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentanol, neopentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3 Dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol, etc.

[0272] Examples of ether compounds with 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, disec-butyl ether, di-n-pentyl ether, diisopentyl ether, disec-pentyl ether, ditert-pentyl ether, and di-n-hexyl ether.

[0273] Examples of alkanes with 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, and cyclononane. Examples of alkenes with 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Examples of alkynes with 6 to 12 carbon atoms include hexyne, heptyne, and octyne.

[0274] In terms of aromatic solvents, examples include toluene, xylene, ethylbenzene, cumene, tert-butylbenzene, and mesitylene.

[0275] Rinsing can reduce the collapse of the resist pattern and the occurrence of defects. Furthermore, rinsing is not always necessary; by not rinsing, the amount of solvent used can be reduced.

[0276] Example

[0277] The present invention will be specifically described below by way of examples of synthesis, embodiments, and comparative examples, but the present invention is not limited to the following embodiments. Furthermore, the apparatus used is as follows.

[0278] •IR: NICOLET 6700, Thermo Fisher Scientific

[0279] · 1 H-NMR: ECA-500 manufactured by Nippon Electronics Co., Ltd.

[0280] MALDITOF-MS: Manufactured by Nippon Electronics Co., Ltd., S3000

[0281] [1] Synthesis of sulfonium salts

[0282] [Synthetic Example 1-1] Synthesis of PAG-1

[0283] [Chemistry 66]

[0284]

[0285] Under a nitrogen atmosphere, starting material M-1 (43.1 g), triethylamine (42.5 g), and 4-dimethylaminopyridine (1.22 g) were dissolved in dichloromethane (431 g). The reaction system was cooled to below 10°C, and methacrylic anhydride (55.8 g) was added dropwise. After addition, the mixture was matured at 20°C for 12 hours. After maturation, the reaction solution was cooled, and saturated sodium bicarbonate solution (200 g) was added dropwise to stop the reaction. Subsequently, a conventional aqueous work-up was performed, the solvent was distilled off, and the mixture was recrystallized with diisopropyl ether to obtain PAG-1 as white crystals (yield 58.1 g, 92% yield).

[0286] The spectral data of PAG-1 are shown below. Also, the nuclear magnetic resonance spectrum (NMR spectrum) is shown below. 1 The results of H-NMR / DMSO-d6 are shown in Figure 1 .

[0287] IR(D-ATR):3371,2973,2927,1737,1677,1637,1608,1477,1454,1379,1317,1 293,1276,1231,1182,1120,1038,1011,947,877,807,714,650,613,583,489cm -1 .

[0288] MALDI-TOFMS: POSITIVE[M + 599 (equivalent to C) 36 H 39 O6S + )

[0289] NEGATIVE[M - ]35 (equivalent to Cl) - )

[0290] [Synthetic Examples 1-2] Synthesis of PAG-2

[0291] [Chemistry 67]

[0292]

[0293] Except for replacing methacrylic anhydride with acryloyl chloride, PAG-2 (14.4 g, 89% yield) was synthesized using the same method as in Synthesis Example 1-1.

[0294] The spectral data of PAG-2 are shown below. Also, the nuclear magnetic resonance spectrum (NMR spectrum) is shown below. 1 The results of H-NMR / DMSO-d6 are shown in Figure 2 .

[0295] IR(D-ATR): 3607,3366,2974,2926,1741,1633,1577,1476,1403,1293,1277,1243,1180,1139,1102,1016,982,901,802,718,667,611,588cm -1 .

[0296] MALDI-TOFMS: POSITIVE[M + 557 (equivalent to C) 33 H 33 O6S + )

[0297] NEGATIVE[M - ]35 (equivalent to Cl) - )

[0298] [Synthetic Examples 1-3] Synthesis of PAG-3

[0299] [Chemistry 68]

[0300]

[0301] Under a nitrogen atmosphere, PAG-1 (14.6 g), raw material M-2 (10.3 g), dichloromethane (40 g), and water (40 g) were added and stirred for 30 minutes. The organic layer was then separated by liquid-liquid extraction and washed five times with water (40 g). The solvent in the organic layer was distilled off, and the mixture was recrystallized with diisopropyl ether to obtain PAG-3 as white crystals (yield 9.3 g, 75% yield).

[0302] The spectral data of PAG-3 are shown below. Also, the nuclear magnetic resonance spectrum (NMR spectrum) is shown below. 1 The results of H-NMR / DMSO-d6 are shown in Figure 3 .

[0303] IR(D-ATR): 3506,2929,2855,1737,1637,1476,1452,1379,1290,1182,1110,1036,1011,990,947,877,807,755,657,609,582,544,528,457cm -1 .

[0304] MALDI-TOFMS: POSITIVE[M + 599 (equivalent to C) 36 H 39 O6S + )

[0305] NEGATIVE[M - 385 (equivalent to C) 14 H 25 O6S3 - )

[0306] [Synthetic Examples 1-4] Synthesis of PAG-4

[0307] [Chemistry 69]

[0308]

[0309] Except that PAG-1 was replaced with PAG-2, PAG-4 (10.3 g, 84% yield) was synthesized using the same method as in Synthesis Examples 1-3.

[0310] The spectral data of PAG-4 are shown below. Also, the nuclear magnetic resonance spectrum (NMR spectrum) is shown below. 1 The results of H-NMR / DMSO-d6 are shown in Figure 4 .

[0311] IR(D-ATR): 3489,3046,2933,2856,1743,1633,1579,1477,1451,1401,1379,1293,1242,1 180,1136,1107,1015,983,959,901,802,764,718,656,628,610,586,544,528,458,403cm -1 .

[0312] MALDI-TOFMS: POSITIVE[M + 557 (equivalent to C) 33 H 33 O6S + )

[0313] NEGATIVE[M -385 (equivalent to C) 14 H 25 O6S3 - )

[0314] [Synthetic Examples 1-5] Synthesis of PAG-5

[0315] [Chemistry 70]

[0316]

[0317] Except for changing the raw material M-2 to sodium styrene sulfonate, PAG-5 (13.7 g, 90% yield) was synthesized using the same method as in Synthesis Examples 1-4.

[0318] The spectral data of PAG-5 are shown below. Also, the nuclear magnetic resonance spectrum (NMR spectrum) is shown below. 1 The results of H-NMR / DMSO-d6 are shown in Figure 5 .

[0319] IR(D-ATR):3048,2972,2926,1743,1633,1477,1399,1294,1277,1240,1206,118 0,1137,1104,1060,1033,1010,987,975,902,841,804,714,674,611,584,553cm -1 .

[0320] MALDI-TOFMS: POSITIVE[M + 557 (equivalent to C) 33 H 33 O6S + )

[0321] NEGATIVE[M - ]183 (equivalent to C8H7O3 S) - )

[0322] [Synthetic Examples 1-6] Synthesis of PAG-6

[0323] [Chemistry 71]

[0324]

[0325] Except for changing the raw material M-2 to sodium styrene sulfonate, PAG-6 (16.1 g, 96% yield) was synthesized using the same method as in Synthesis Examples 1-3.

[0326] The spectral data of PAG-6 are shown below. Also, the nuclear magnetic resonance spectrum (NMR spectrum) is shown below. 1 The results of H-NMR / DMSO-d6 are shown in Figure 6 .

[0327] IR(D-ATR):3453,2972,2927,1729,1637,1475,1452,1379,1317,1294,1276,1216, 1202,1180,1119,1034,1010,943,891,843,810,714,675,612,582,557,505,487cm -1 .

[0328] MALDI-TOFMS: POSITIVE[M + 599 (equivalent to C) 36 H 39 O6S + )

[0329] NEGATIVE[M - ]183 (equivalent to C8H7O3 S) - )

[0330] [Synthetic Examples 1-7] Synthesis of PAG-7

[0331] [Chemistry 72]

[0332]

[0333] Except for changing feedstock M-2 to feedstock M-3, PAG-7 (15.9 g, 86% yield) was synthesized using the same method as in Synthesis Examples 1-4.

[0334] The spectral data of PAG-7 are shown below. Also, the nuclear magnetic resonance spectrum (NMR spectrum) is shown below. 1 The results of H-NMR / DMSO-d6 are shown in Figure 7 .

[0335] IR(D-ATR): 3480,3050,2971,2928,1743,1633,1608,1476,1404,1377,1328,1245,1181 ,1139,1101,1071,1015,991,902,860,840,802,777,712,667,642,610,574,552,521cm -1 .

[0336] MALDI-TOFMS: POSITIVE[M + 557 (equivalent to C) 33 H 33 O6S + )

[0337] NEGATIVE[M - ]359 (equivalent to C) 12 H8F5O5S - )

[0338] [Synthetic Examples 1-8] Synthesis of PAG-8

[0339] [Chemistry 73]

[0340]

[0341] Except for changing the feedstock M-1 to feedstock M-4, PAG-8 (32.1 g, 92% yield) was synthesized using the same method as in Synthesis Example 1-1.

[0342] The spectral data of PAG-8 are shown below. Also, the nuclear magnetic resonance spectrum (NMR spectrum) is shown below. 1 The results of H-NMR / DMSO-d6 are shown in Figure 8 .

[0343] IR(D-ATR):3379,2974,2926,1735,1636,1477,1446,1379,1317,1293,1277, 1182,1120,1040,1011,947,878,808,751,714,685,649,613,568,522,492cm -1 .

[0344] MALDI-TOFMS: POSITIVE[M + ]487 (equivalent to C) 30 H 31 O4S + )

[0345] NEGATIVE[M - ]35 (equivalent to Cl) - )

[0346] [Synthetic Examples 1-9] Synthesis of PAG-9

[0347] [Chemistry 74]

[0348]

[0349] Except that PAG-1 was replaced with PAG-8, PAG-9 (16.5 g, 89% yield) was synthesized using the same method as in Synthesis Examples 1-3.

[0350] The spectral data of PAG-9 are shown below. Also, the nuclear magnetic resonance spectrum (NMR spectrum) is shown below. 1The results of H-NMR / DMSO-d6 are shown in Figure 9 .

[0351] IR(D-ATR): 3506,3056,2929,2854,1738,1637,1476,1448,1379,1289,1258,118 3,1110,1012,990,948,892,852,807,754,713,686,657,609,582,544,528,456cm -1 .

[0352] MALDI-TOFMS: POSITIVE[M + ]487 (equivalent to C) 30 H 31 O4S + )

[0353] NEGATIVE[M - 385 (equivalent to C) 14 H 25 O6S3 - )

[0354] [Synthetic Examples 1-10 to 1-20] Synthesis of PAG-10 to PAG-20

[0355] PAG-10 to PAG-20 were synthesized using various organic synthesis reactions.

[0356] [Chemistry 75]

[0357]

[0358] [Chemistry 76]

[0359]

[0360] [2] Comparison of the synthesis of base polymers for resist compositions

[0361] [Comparative Synthesis Example 1] Synthesis of Polymer P-1

[0362] A solution was prepared by dissolving p-hydroxystyrene (27.8 g), 1-methylcyclopentyl methacrylate (72.2 g), and dimethyl 2,2'-azobisisobutyrate (6.08 g) in PGMEA (155 g) under a nitrogen atmosphere. This solution was added dropwise over 6 hours to PGMEA (78 g) that had been stirred at 80°C under a nitrogen atmosphere. After the addition was complete, the mixture was stirred at 80°C for 2 hours 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 under vacuum at 50°C for 20 hours to obtain polymer P-1 as a white powder. The yield was 85 g, representing a yield of 85%.

[0363] [Chemistry 77]

[0364]

[0365] [Comparative Synthesis Example 2] Synthesis of Polymer P-2

[0366] Except for changing the type and blending ratio of monomers, polymer P-2 was produced using the same method as in Comparative Synthesis Example 1.

[0367] [Chemistry 78]

[0368]

[0369] [3] Preparation of the resist composition

[0370] [Examples 1-1 to 1-20, Comparative Examples 1-1 to 1-8]

[0371] Sulfonium salts (PAG-1 to PAG-20) were dissolved in solvents according to the compositions shown in Table 1 below. The resulting solutions were filtered through a 0.2 μm Teflon (registered trademark) filter to prepare molecular resist compositions (R-1 to R-20). Furthermore, for comparative applications, polymers, photoacid generators, sensitivity modifiers, surfactants, and solvents were mixed according to the compositions shown in Table 1 below and filtered through a 0.2 μm Teflon (registered trademark) filter to prepare comparative resist compositions (CR-1 to CR-8).

[0372] [Table 1]

[0373]

[0374] Table 1 lists the following components: ferrous salts (I-1 to I-3), photoacid generators (PAG-A to PAG-C), sensitivity modifiers (QA, QB), nonionic monomers (Y-1), surfactants (SF-1), and solvents.

[0375] [Chemistry 79]

[0376]

[0377] [Chemistry 80]

[0378]

[0379] [Chemistry 81]

[0380]

[0381] SF-1: PF636 (manufactured by OMNOVA)

[0382] Solvent: PGMEA (Propylene Glycol Monomethyl Ether Acetate)

[0383] DAA (diacetone alcohol)

[0384] [4] Evaluation of EB lithography

[0385] [Examples 2-1 to 2-20, Comparative Examples 2-1 to 2-8]

[0386] Each resist composition (R-1 to R-20, CR-1 to CR-8) was spin-coated onto a Si substrate on which a 60 nm thick antireflective film DUV-42 manufactured by Nikkei Chemical Co., Ltd. was formed. A 50 nm thick resist film was then pre-baked at 100°C for 60 seconds using a heated plate. The resist film was exposed using an EB painting apparatus (ELS-F125, accelerating voltage 125 kV) manufactured by ELIONIX Corporation. PEB was applied on a heated plate at the temperatures listed in Table 2 for 60 seconds, followed by development with a 2.38% by mass TMAH aqueous solution for 30 seconds to form a pattern. In Examples 2-1 to 2-20, Comparative Examples 2-2, and Comparative Examples 2-5 to 2-8, the resist film residue in the exposed areas showed negative tone characteristics. In Comparative Examples 2-3 and 2-4, the resist film residue in the unexposed areas showed positive tone characteristics. As a result, line-and-spacing (LS) patterns with a spacing width of 40 nm and a pitch of 80 nm were obtained, either negative or positive. Furthermore, in Comparative Example 2-1, pattern formation was not confirmed. Sensitivity, LWR, and limiting resolution were evaluated for the obtained LS patterns using the methods described below. The results are shown in Table 2.

[0387] [Sensitivity Evaluation]

[0388] The aforementioned LS pattern was observed using a CD-SEM (CG-5000) manufactured by Hitachi High-Tech, and the optimal exposure value Eop (μC / cm) was determined to obtain an LS pattern with a spacing width of 40nm and a pitch of 80nm. 2 ), and define it as sensitivity.

[0389] [LWR Evaluation]

[0390] For LS patterns obtained by irradiation with the optimal exposure dose (Eop), the dimensions at 10 points along the long side of the pitch width were measured using a CD-SEM (CG-5000) manufactured by Hitachi High-Tech. The standard deviation (σ) of the results was calculated as 3σ, which was taken as the LWR. The smaller this value, the more uniform and less rough the pitch width pattern can be obtained.

[0391] [Limited Resolution Evaluation]

[0392] The minimum linewidth (nm) of the LS pattern separated at the optimal exposure level (Eop) is defined as the limiting resolution.

[0393] [Table 2]

[0394]

[0395] As shown in Table 2, the molecular resist composition of the present invention exhibits superior sensitivity, LWR, and limiting resolution in negative pattern formation using alkaline aqueous solution development in EB lithography compared to positive resist compositions using polymeric positive resist compositions and nonionic monomers. Furthermore, it is evident that excellent sensitivity and LWR can be obtained by adding sulfonium salts. The results of Examples 2-3 to 2-5 and Comparative Examples 2-6 to 2-8 clearly demonstrate that even when the main component (sulfonium salt with polymerizable functional groups) of the molecular resist composition is the same, the former containing the sulfonium salt used in the present invention exhibits a lower optimal exposure (improved sensitivity) and a smaller LWR compared to the latter without it.

[0396] [5] Evaluation of EUV lithography

[0397] [Examples 3-1 to 3-20, Comparative Examples 3-1 to 3-8]

[0398] Each resist composition (R-1 to R-20, CR-1 to CR-8) was spin-coated onto a Si substrate with a silicon-containing spin-coated hard mask SHB-A940 (43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd., with a film thickness of 20 nm. A 40 nm thick resist film was then pre-baked at 100 °C for 60 seconds using a hot plate. A 22 nm LS1:1 pattern was exposed using an ASML EUV scanning exposure machine NXE3300 (NA 0.33, σ 0.9, 90-degree dipole illumination). The pattern was then formed by PEB treatment on a hot plate at the temperatures listed in Table 3 for 60 seconds, followed by development with a 2.38% by mass TMAH aqueous solution for 30 seconds. In Examples 3-1 to 3-20, Comparative Examples 3-2 and 3-5 to 3-8, resist film residue was observed in the exposed areas; in Comparative Examples 3-3 and 3-4, resist film residue was observed in the unexposed areas. As a result, LS patterns with a spacing width of 22 nm and a pitch of 44 nm were obtained, either negative or positive. Furthermore, in Comparative Example 3-1, pattern formation was not confirmed. 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.

[0399] [Sensitivity Evaluation]

[0400] The aforementioned LS pattern was observed using a CD-SEM (CG-5000) manufactured by Hitachi High-Tech, and the optimal exposure Eop (mJ / cm²) was determined to obtain an LS pattern with a spacing width of 22nm and a pitch of 44nm. 2 ), and define it as sensitivity.

[0401] [LWR Evaluation]

[0402] For LS patterns obtained by irradiation with the optimal exposure dose (Eop), the dimensions at 10 points along the long side of the pitch width were measured using a CD-SEM (CG-5000) manufactured by Hitachi High-Tech. The standard deviation (σ) of the results was calculated as 3σ, which was taken as the LWR. The smaller this value, the more uniform and less rough the pitch width pattern can be obtained.

[0403] [Limited Resolution Evaluation]

[0404] The minimum linewidth (nm) of the LS pattern separated at the optimal exposure level (Eop) is defined as the limiting resolution.

[0405] [Table 3]

[0406]

[0407] As shown in Table 3, the molecular resist composition of the present invention, even in EUV lithography, exhibits superior sensitivity, LWR, and limiting resolution compared to positive resist compositions using polymeric positive resist compositions and nonionic monomers, when forming negative patterns by alkaline aqueous solution development, similar to EB lithography. Furthermore, it is evident that excellent sensitivity and LWR can be obtained by adding sulfonium salts. The results of Examples 3-3 to 3-5 and Comparative Examples 3-6 to 3-8 clearly demonstrate that even when the main component (sulfonium salt with polymeric functional groups) of the molecular resist composition is the same, the former containing the sulfonium salt used in the present invention exhibits a lower optimal exposure (improved sensitivity) and a smaller LWR compared to the latter without it.

[0408] This specification contains the following specifications.

[0409] [1]: A molecular resist composition, characterized in that: it contains a sulfonium salt represented by formula (1) or (2), a sulfonium cation represented by formula (1-1), and a sulfonium salt containing a halide ion, nitrate ion, hydrogen sulfate ion, bicarbonate ion, tetraphenylborate ion or an anion represented by any of formulas (1-2) to (1-8), and an organic solvent, and does not contain a base polymer;

[0410] [Chemistry 82]

[0411]

[0412] In the formula, n is an integer from 1 to 3; A 1 It is a hydrocarbon group with 2 to 20 carbon atoms containing a polymerizable functional group; this hydrocarbon group may also contain heteroatoms; A 2 It contains polymerizable functional groups and is compatible with Ar 1B Two carbon atoms together form a group with an alicyclic ring having 4 to 20 carbon atoms; this alicyclic ring may also contain heteroatoms; Ar 1A It is an arylene group with 6 to 20 carbon atoms, in which some or all of the hydrogen atoms on the aromatic ring may be replaced by halogen atoms, or by a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; Ar 1B It is a trivalent aromatic hydrocarbon group with 6 to 20 carbon atoms, wherein some or all of the hydrogen atoms on the aromatic ring of the trivalent aromatic hydrocarbon group may be replaced by halogen atoms, or it may contain a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; Ar 2 It is an aryl group with 6 to 20 carbon atoms, in which some or all of the hydrogen atoms on the aromatic ring may be replaced by halogen atoms, or by a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; also, 2 Ar 1A 2 Ar 1B 2 Ar 2 Ar 1A with Ar 2 、or Ar1B with Ar 2 They can also bond to each other and form rings together with the sulfur atoms they are bonded to; X - It is a relative anion;

[0413] [Chemistry 83]

[0414]

[0415] In the formula, R 31 R 32 Each is an independent halogen atom, or may contain heteroatoms, and is a hydrocarbon group with 1 to 30 carbon atoms;

[0416] [Chemistry 84]

[0417]

[0418] In the formula, k1 and k2 are each independently 1, 2, 3, or 4; Rf 1 and Rf 2 Each is independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms; however, all Rf 1 and Rf 2 It cannot be both a hydrogen atom and a hydrogen atom; R 41 It can be a hydrogen atom, a halogen atom, a hydroxyl group, or a hydrocarbon group with 1 to 50 carbon atoms that may contain heteroatoms; R 42 It is a hydrocarbon group with 1 to 50 carbon atoms, consisting of hydrogen atoms, halogen atoms, hydroxyl groups, or heteroatoms; however, it excludes those in which the hydrogen atoms at the α and β positions of the sulfonate group are replaced by fluorine atoms or fluoroalkyl groups; R 51 It can be a hydrogen atom, a halogen atom, a hydroxyl group, or a hydrocarbon group with 1 to 50 carbon atoms that may contain heteroatoms; R 52 It is a hydrocarbon group with 1 to 50 carbon atoms, consisting of hydrogen atoms, halogen atoms, hydroxyl groups, or heteroatoms; however, it excludes those in which the hydrogen atoms at the α and β positions of the carboxyl group are replaced by fluorine atoms or fluoroalkyl groups; R 61 and R 62 Each can be an independent hydrocarbon group with 1 to 50 carbon atoms, which may also contain heteroatoms; R 71 ~R 73 Each can be an independent hydrocarbon group with 1 to 50 carbon atoms, which may also contain heteroatoms; R 81 It is a fluorine atom or a fluorinated hydrocarbon group having 1 to 10 carbon atoms; the fluorinated hydrocarbon group may also contain a hydroxyl group, an ether bond, or an ester bond; R 82 It consists of a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms; this hydrocarbon group may also contain a hydroxyl group, an ether bond, or an ester bond; furthermore, R 81 With R 82 They can also bond to each other and form rings together with the atoms they are bonded to.

[0419] [2]: As in [1], molecular resist composition, wherein the aforementioned A 1 Acryloyloxy, methacryloyloxy, or may contain a cycloalkenyl group with 3 to 20 carbon atoms, a cycloalkenyloxy group with 3 to 20 carbon atoms, a cycloalkenylcarbonyloxy group with 3 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms, or an alkenyloxy group with 2 to 20 carbon atoms, as described above A 2 To be with Ar 1B Two carbon atoms together form a cycloalkene ring with 4 to 20 carbon atoms, which may also contain heteroatoms, or a polycyclic group with 4 to 20 carbon atoms and one double bond.

[0420] [3]: Molecular resist compositions such as [1] or [2], wherein the aforementioned X - It is the same as the relative anion of the ferric cation represented by the aforementioned formula (1-1).

[0421] [4]: Molecular resist composition of any one of [1] to [3], wherein the anion represented by any one of the aforementioned formulas (1-2) to (1-8) contains a polymeric functional group.

[0422] [5]: Molecular resists such as any one of [1] to [4] also contain free radical scavengers.

[0423] [6]: Molecular resist compositions such as any one of [1] to [5] also contain surfactants.

[0424] [7]: A pattern forming method, characterized by comprising the following steps: forming a resist film on a substrate using a molecular resist composition such as [1] to [6]; exposing the resist film to high-energy rays; and developing the exposed resist film using a developer.

[0425] [8]: The pattern forming method of [7] uses an alkaline aqueous solution as the aforementioned developing solution to dissolve the exposed part and obtain a positive pattern in which the unexposed part does not dissolve.

[0426] [9]: The pattern forming method of [7] uses an organic solvent or an alkaline aqueous solution as the aforementioned developing solution to dissolve the unexposed part and obtain a negative pattern in which the exposed part does not dissolve.

[0427]

[10] : The pattern forming method of [9] uses a mixture selected from 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methyl acetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butenyl acetate, isoamyl acetate, cyclohexyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl valerate, methyl crotonate, ethyl crotonate. At least one of the following is used as the organic solvent of the aforementioned developing solution: 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 formate, phenyl ethyl formate, methyl 3-phenylpropionate, benzyl propionate, and 2-phenylethyl acetate.

[0428]

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

[10] uses an electron beam or extreme ultraviolet light as the aforementioned high-energy rays.

[0429] Furthermore, the present invention is not limited to the embodiments described above. The embodiments described above are examples; any embodiment having a substantially the same structure as the technical concept described in the claims of the present invention and performing the same effect is included within the technical scope of the present invention.

Claims

1. A molecular resist composition, characterized in that: The product contains a sulfonium salt represented by formula (1) or (2), a sulfonium cation represented by formula (1-1), and a sulfonium salt represented by a halide ion, nitrate ion, hydrogen sulfate ion, bicarbonate ion, tetraphenylborate ion or an anion represented by any of formulas (1-2) to (1-8), and an organic solvent, and does not contain a base polymer. In the formula, n is an integer from 1 to 3; A 1 It is a hydrocarbon group with 2 to 20 carbon atoms containing a polymerizable functional group; this hydrocarbon group may also contain heteroatoms; A 2 It contains polymerizable functional groups and is compatible with Ar 1B Two carbon atoms together form a group with an alicyclic ring having 4 to 20 carbon atoms; this alicyclic ring may also contain heteroatoms; Ar 1A It is an arylene group with 6 to 20 carbon atoms, in which some or all of the hydrogen atoms on the aromatic ring may be replaced by halogen atoms, or by a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; Ar 1B It is a trivalent aromatic hydrocarbon group with 6 to 20 carbon atoms, wherein some or all of the hydrogen atoms on the aromatic ring of the trivalent aromatic hydrocarbon group may be replaced by halogen atoms, or it may contain a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; Ar 2 It is an aryl group with 6 to 20 carbon atoms, in which some or all of the hydrogen atoms on the aromatic ring may be replaced by halogen atoms, or by a hydrocarbon group with 1 to 20 carbon atoms containing heteroatoms; also, 2 Ar 1A 2 Ar 1B 2 Ar 2 Ar 1A with Ar 2 、or Ar 1B with Ar 2 They can also bond to each other and form rings together with the sulfur atoms they are bonded to; X - It is a relative anion; In the formula, R 31 R 32 Each is an independent halogen atom, or may contain heteroatoms, and is a hydrocarbon group with 1 to 30 carbon atoms; In the formula, k1 and k2 are each independently 1, 2, 3, or 4; Rf 1 and Rf 2 Each is independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms; however, all Rf 1 and Rf 2 It cannot be both a hydrogen atom and a hydrogen atom; R 41 It can be a hydrogen atom, a halogen atom, a hydroxyl group, or a hydrocarbon group with 1 to 50 carbon atoms that may contain heteroatoms; R 42 It is a hydrocarbon group with 1 to 50 carbon atoms, consisting of hydrogen atoms, halogen atoms, hydroxyl groups, or heteroatoms; however, it excludes those in which the hydrogen atoms at the α and β positions of the sulfonate group are replaced by fluorine atoms or fluoroalkyl groups; R 51 It can be a hydrogen atom, a halogen atom, a hydroxyl group, or a hydrocarbon group with 1 to 50 carbon atoms that may contain heteroatoms; R 52 It is a hydrocarbon group with 1 to 50 carbon atoms, consisting of hydrogen atoms, halogen atoms, hydroxyl groups, or heteroatoms; however, it excludes those in which the hydrogen atoms at the α and β positions of the carboxyl group are replaced by fluorine atoms or fluoroalkyl groups; R 61 and R 62 Each can be an independent hydrocarbon group with 1 to 50 carbon atoms, which may also contain heteroatoms; R 71 ~R 73 Each can be an independent hydrocarbon group with 1 to 50 carbon atoms, which may also contain heteroatoms; R 81 It is a fluorine atom or a fluorinated hydrocarbon group having 1 to 10 carbon atoms; the fluorinated hydrocarbon group may also contain a hydroxyl group, an ether bond, or an ester bond; R 82 It consists of a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms; this hydrocarbon group may also contain a hydroxyl group, an ether bond, or an ester bond; furthermore, R 81 With R 82 They can also bond to each other and form rings together with the atoms they are bonded to.

2. The molecular resist composition according to claim 1, wherein, The A 1 It can be an acryloxy group, a methacryloyloxy group, or a cycloalkenyl group with 3 to 20 carbon atoms containing heteroatoms, a cycloalkenyloxy group with 3 to 20 carbon atoms containing heteroatoms, a cycloalkenylcarbonyloxy group with 3 to 20 carbon atoms containing heteroatoms, an alkenyl group with 2 to 20 carbon atoms containing heteroatoms, or an alkenyloxy group with 2 to 20 carbon atoms containing heteroatoms. This A... 2 To be with Ar 1B Two carbon atoms together form a cycloalkene ring with 4 to 20 carbon atoms, which may also contain heteroatoms, or a polycyclic group with 4 to 20 carbon atoms and one double bond.

3. The molecular resist composition according to claim 1, wherein, The X - It is the same as the relative anion of the citric acid represented by formula (1-1).

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

5. The molecular resist composition according to claim 1 further comprises a free radical scavenger.

6. The molecular resist composition according to claim 1 further comprises a surfactant.

7. A pattern forming method, characterized in that, The method includes the following steps: 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 radiation; and developing the exposed resist film using a developer.

8. The pattern forming method according to claim 7, wherein an alkaline aqueous solution is used as the developing solution to dissolve the exposed portion, thereby obtaining a positive pattern in which the unexposed portion does not dissolve.

9. The pattern forming method according to claim 7, wherein an organic solvent or an alkaline aqueous solution is used as the developing solution to dissolve the unexposed portion, thereby obtaining a negative pattern in which the exposed portion does not dissolve.

10. The pattern forming method according to claim 9, wherein the following are used: 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methyl acetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butenyl acetate, isoamyl acetate, cyclohexyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl valerate, methyl crotonate, crotonic acid At least one of the following is used as the organic solvent of the developer: ethyl acetate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, ethyl phenylacetate, benzyl formate, phenyl ethyl formate, methyl 3-phenylpropionate, benzyl propionate, and 2-phenylethyl acetate.

11. The pattern forming method according to claim 7, wherein an electron beam or extreme ultraviolet light is used as the aforementioned high-energy ray.

Images