Radiation-sensitive resin composition, pattern formation method, method for producing electronic device, acid generation agent, method for producing compound, compound, and acid generation method

Abstract

Provided is a radiation-sensitive resin composition comprising an acid generation agent represented by general formula (AG1). In general formula (AG1), R1 and R2 each independently represent a fluorine atom or -OR, R is a monovalent organic group, and A+ is a counter cation. Also provided is an acid generation agent represented by general formula (AG1). Further provided is a compound represented by general formula (AG1).

Description

Radiation-sensitive resin composition, pattern forming method, method for manufacturing electronic device, acid generator, method for manufacturing compound, compound and acid generating method

[0001] The present invention relates to a radiation-sensitive resin composition, a pattern forming method, a method for producing an electronic device, an acid generator, a method for producing a compound, a compound, and an acid generating method.

[0002] In the manufacture of electronic devices, radiation-sensitive resin compositions such as photoresists are used to form fine patterns on substrates. Typically, a resin film formed on a substrate using a radiation-sensitive resin composition is irradiated with radiation and then developed to form a pattern on the substrate. This pattern is used as a mask to perform dry etching or the like to form a fine circuit on the substrate. As electronic devices become increasingly miniaturized and complex, improvements in radiation-sensitive resin compositions are also continuing.

[0003] Most radiation-sensitive resin compositions for forming nanometer-order fine patterns are chemically amplified. In chemically amplified radiation-sensitive resin compositions, one acid generated from an acid generator catalytically participates multiple times in the solubilization or insolubilization reaction of the composition. Therefore, chemically amplified radiation-sensitive resin compositions can be easily designed to have relatively high sensitivity.

[0004] Chemically amplified radiation-sensitive resin compositions are broadly divided into the following two types: (i) those containing a resin that decomposes under the action of an acid, thereby changing its solubility in a developer, and a compound (acid generator) that generates an acid upon irradiation with radiation; and (ii) those containing a component (e.g., a resin and a crosslinking agent) that polymerizes under the action of an acid, thereby changing its solubility in a developer, and an acid generator.

[0005] Patent Document 1 describes, for example, ３ SO ２ ) ３ C －An energy active salt having an anion represented by the formula (I) is described. This energy active salt can be used as an acid generator in a radiation-sensitive resin composition. Patent Document 2 describes a radiation-sensitive resin composition containing an acid generator characterized by a cationic structure. Patent Document 3 also describes various acid generators that can be used in radiation-sensitive resin compositions. Many acid generators contain a fluorine atom, which has a high electronegativity. This is to increase the acid strength of the generated acid and thereby enhance the sensitivity of the radiation-sensitive resin composition.

[0006] Japanese Patent No. 3985020 Japanese Patent No. 5645510 Japanese Patent Laid-Open No. 2002-341539

[0007] As described above, with the advancement of miniaturization and complexity in electronic devices, improvements in radiation-sensitive resin compositions are being continuously made. As improvements in radiation-sensitive resin compositions are being investigated, there is a potential need for novel acid generators that can improve some of the performance of radiation-sensitive resin compositions.

[0008] The present inventors have conducted investigations with the aim of providing a novel acid generator and a radiation-sensitive resin composition containing the same.

[0009] The present inventors have completed the following radiation-sensitive resin composition and the like.

[0010] 1. A radiation-sensitive resin composition containing an acid generator represented by the following general formula (AG1): In general formula (AG1), R １ and R ２ are each independently a fluorine atom or —OR, where R is a monovalent organic group, and A ＋ is a counter cation. 2. The radiation-sensitive resin composition according to 1., comprising a resin that decomposes under the action of an acid, thereby changing its solubility in a developer. 3. The radiation-sensitive resin composition according to 1., comprising a component that undergoes polymerization under the action of an acid, thereby changing its solubility in a developer. 4. The radiation-sensitive resin composition according to any one of 1. to 3., comprising R １ and R ２and R are both fluorine atoms. １ and R ２ 6. The radiation-sensitive resin composition according to any one of 1. to 5., wherein one of R is a fluorine atom and the other is —OR. １ and R ２ 7. The radiation-sensitive resin composition according to any one of 1. to 6., wherein at least one of A is —OR, and R contains a cyclic skeleton. ＋ is at least one cation selected from the group consisting of a sulfonium cation and an iodonium cation. 8. A pattern forming method comprising: forming a film using the radiation-sensitive resin composition according to any one of 1. to 7., irradiating the film with radiation, and developing the film that has been irradiated with radiation. 9. A method for manufacturing an electronic device, comprising the pattern forming method according to 8. 10. An acid generator represented by the following general formula (AG1): In general formula (AG1), R １ and R ２ are each independently a fluorine atom or —OR, where R is a monovalent organic group, and A ＋ 11. The acid generator according to 10., wherein R １ and R ２ 12. The acid generator according to 10. or 11., wherein R １ and R ２ 13. The acid generator according to 10., wherein one of R is a fluorine atom and the other is —OR. １ and R ２ 14. An acid generator according to any one of 10. to 13., wherein at least one of A is —OR, and R contains a cyclic skeleton. ＋is at least one cation selected from the group consisting of a sulfonium cation and an iodonium cation. １ ＋ X － (A １ ＋ is a sulfonium cation or an iodonium cation, and X － is a halide ion, a sulfonate ion, a sulfate ion, a phosphate ion, a hydroxide ion, or a carboxylate ion), to produce a compound represented by general formula (AG1-1): In general formula (ag1), M ＋ is a metal cation, R １ and R ２ are each independently a fluorine atom or —OR, and R is a monovalent organic group. In general formula (AG1-1), A １ ＋ The definition of is as described above, and R １ and R ２ are each independently a fluorine atom or —OR, and R is a monovalent organic group. 16. A method for producing a compound, comprising a step of reacting a compound represented by general formula (M-FSM) below with a compound represented by R—OH, where R is a monovalent organic group, to obtain a compound represented by general formula (ag1) below. In the general formula (M-FSM), M ＋ is a metal cation. In general formula (ag1), M ＋ is a metal cation, R １ and R ２ are each independently a fluorine atom or —OR, provided that R １ and R ２ At least one of the above is —OR, and R is a monovalent organic group. 17. A compound represented by the following general formula (AG1): In general formula (AG1), R １ and R ２are each independently a fluorine atom or —OR, where R is a monovalent organic group, and A ＋ is a counter cation. 18. The compound according to 17, wherein R １ and R ２ 19. The compound according to 17. or 18., wherein R １ and R ２ 20. A compound according to 17., wherein one of R is a fluorine atom and the other is —OR. １ and R ２ 21. A compound according to any one of 17. to 20., wherein at least one of A is —OR, and R contains a cyclic skeleton. ＋ is at least one cation selected from the group consisting of a sulfonium cation and an iodonium cation. 22. A method for generating an acid, comprising irradiating the compound according to any one of 17. to 21. with radiation to generate an acid.

[0011] The novel acid generator and radiation-sensitive resin composition described above are useful in forming a pattern by forming a resin film on a substrate, irradiating it with radiation, and then developing it.

[0012] Hereinafter, embodiments of the present invention will be described in detail. In this specification, the expression "X to Y" in the description of a numerical range means X or more and Y or less, unless otherwise specified. For example, "1 to 5% by mass" means "1% by mass or more and 5% by mass or less." In this specification, "non-volatile components" refers to components other than the solvent in the radiation-sensitive resin composition, unless otherwise specified. In this specification, "radiation" refers to light or particle beams capable of activating an acid generator. Typically, radiation can be ultraviolet light (particularly far ultraviolet and extreme ultraviolet light), X-rays, gamma rays, electron beams, etc. Furthermore, in this specification, unless otherwise specified, "light" is synonymous with "radiation." In this specification, "acid generator" typically refers to a compound that has the property of generating an acid in response to an external stimulus (external energy) such as light or heat. For example, a compound represented by a certain general formula X but that does not generate an acid in response to an external stimulus does not fall under the category of an "acid generator represented by general formula X." In contrast, for example, "a compound represented by general formula X" encompasses all compounds represented by general formula X, regardless of properties such as responsiveness to external stimuli.

[0013] In the description of groups (atomic groups) in this specification, when a notation does not specify whether the group is substituted or unsubstituted, it encompasses both those that have no substituents and those that have a substituent. For example, the term "alkyl group" encompasses not only alkyl groups that have no substituents (unsubstituted alkyl groups) but also alkyl groups that have a substituent (substituted alkyl groups). The term "(meth)acrylic" in this specification represents a concept that encompasses both acrylic and methacrylic. The same applies to similar notations such as "(meth)acrylate." In this specification, the term "organic group" refers to an atomic group obtained by removing one or more hydrogen atoms from an organic compound, unless otherwise specified. For example, a "monovalent organic group" refers to an atomic group obtained by removing one hydrogen atom from any organic compound.

[0014] In this specification, the term "electronic device" is used to encompass elements, devices, final products, etc. to which electronic engineering technology is applied, such as semiconductor chips, semiconductor elements, printed wiring boards, electric circuit display devices, information and communication terminals, light-emitting diodes, physical batteries, and chemical batteries.

[0015] <Radiation-Sensitive Resin Composition> A radiation-sensitive resin composition containing an acid generator represented by general formula (AG1) below is novel, and can be suitably used for pattern formation by forming a resin film on a substrate, followed by irradiation with radiation and development treatment.

[0016]

[0017] In general formula (AG1), R １ and R ２ are each independently a fluorine atom or —OR, where R is a monovalent organic group, and A ＋ is the counter cation.

[0018] The advantages of using an acid generator represented by general formula (AG1) to form a radiation-sensitive resin composition will be described below, taking into account conventional knowledge.

[0019] The acid generated from the acid generator represented by general formula (AG1) has a strong electron-withdrawing property, i.e., -SO ２ The acid generator represented by general formula (AG1) has an F structure. This is thought to result in an increased acid strength of the generated acid. This is thought to lead to increased sensitivity of the radiation-sensitive resin composition. Furthermore, according to the studies of the present inventors, although the acid generator represented by general formula (AG1) exists stably in an organic solvent, the acid generated from the acid generator represented by general formula (AG1) easily decomposes upon contact with an alkaline developer (an alkaline aqueous solution) (it is thought that the S—F bond is hydrolyzed). Therefore, when a pattern is formed on a substrate using the acid generator represented by general formula (AG1), it is thought that unintended residue of fluorine-containing components derived from the acid generator on the substrate is reduced. Incidentally, the fact that the number of fluorine atoms in the anion moiety in general formula (AG1) is originally relatively small is also thought to contribute to the reduction in residue of fluorine-containing components.

[0020] Many conventional acid generators contain electron-withdrawing fluorine atoms to achieve high resolution and low roughness when used in radiation-sensitive resin compositions, while also increasing the acid strength of the generated acid to achieve high sensitivity. However, there are concerns that fluorine-containing components derived from the acid generator may unintentionally remain on the substrate, adversely affecting the yield and performance of electronic devices. Specifically, there is a concern that unintentional residue of fluorine-containing components may affect the dry etching rate. In other words, if fluorine-containing components derived from the radiation-sensitive resin composition unintentionally remain on the substrate, there is a concern that appropriate dry etching may not be performed. Furthermore, because many fluorine-containing compounds are water-repellent, there is a concern that unintentional residue of fluorine-containing compounds on the substrate may unintentionally change the properties of the substrate surface. In particular, with the recent advances in miniaturization and complexity of electronic devices, even trace amounts of residue that were not previously a problem may become problematic.

[0021] In order to reduce the unintended residue of fluorine-containing compounds on the substrate, it is conceivable to use an acid generator that does not contain fluorine atoms. However, many acid generators that do not contain fluorine atoms have a low acid strength, which may result in a decrease in the sensitivity of the radiation-sensitive resin composition. In other words, it can be considered that there is a trade-off between increasing the acid strength of the generated acid to increase the sensitivity of the radiation-sensitive resin composition and reducing the unintended residue of fluorine-containing compounds on the substrate.

[0022] Furthermore, in recent years, there have been cases where it has been required to reduce the amount of fluorine used itself from the viewpoint of preventing environmental pollution and health hazards.

[0023] It is believed that the above concerns and problems can be overcome by preparing a radiation-sensitive resin composition using an acid generator represented by general formula (AG1). In particular, attention should be paid to overcoming the trade-off between increasing the acid strength of the generated acid to increase the sensitivity of the radiation-sensitive resin composition and reducing the amount of unintended fluorine-containing compounds remaining on the substrate.

[0024] General formula (AG1) will be explained in more detail below.

[0025] Structure of the anion side As described above, in general formula (AG1), R １ and R ２ are each independently a fluorine atom or —OR, and R is a monovalent organic group. １ and R ２ is preferably selected appropriately in view of the acid strength and diffusibility of the generated acid.

[0026] In terms of increasing the acid strength of the generated acid, R １ and R ２ Preferably, at least one of R is a fluorine atom, １ and R ２ It is more preferable that both of the radicals are fluorine atoms. When the acid strength of the generated acid is increased, the sensitivity of the radiation-sensitive resin composition tends to be improved.

[0027] From the viewpoint of controlling the diffusibility of generated acid, R １ and R ２ Preferably, at least one of the groups is —OR. By adjusting the molecular weight and bulkiness of R, the diffusibility of the generated acid can be adjusted in various ways. By appropriately adjusting the diffusibility of the generated acid, the radiation-sensitive resin composition tends to have good performance, such as resolution and line edge roughness.

[0028] R is not particularly limited as long as it is a monovalent organic group. However, from the viewpoint of suppressing the diffusion of the generated acid and improving resolution and line edge roughness, it is preferable that R contain a cyclic skeleton. More specifically, R may contain a monocyclic or polycyclic aliphatic hydrocarbon group, a monocyclic or polycyclic aromatic hydrocarbon group, or the like. R may contain a heterocyclic group, which may be aromatic or non-aromatic. Examples of heteroatoms contained in the heterocyclic group include an oxygen atom, a nitrogen atom, and a sulfur atom. R may be a group having only a cyclic skeleton as a chemical structure (e.g., a monocyclic or polycyclic aliphatic hydrocarbon group, a monocyclic or polycyclic aromatic hydrocarbon group itself), or may be a group having a cyclic skeleton and a chemical structure other than the cyclic skeleton. Specifically, -OR may be -O-L-R'. Here, L is a divalent linking group, and R' is a monocyclic or polycyclic aliphatic hydrocarbon group, a monocyclic or polycyclic aromatic hydrocarbon group, or a heterocyclic group. Examples of the divalent linking group for L include a linear or branched alkylene group and a carbonyl group.

[0029] Examples of the monocyclic aliphatic hydrocarbon group include a cycloalkyl group and a cycloalkenyl group. Specific examples include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclobutyl group, a cyclooctyl group, a cyclododecanyl group, a cyclopentenyl group, a cyclohexenyl group, and a cyclooctadienyl group. Among these, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group are preferred. Examples of the polycyclic aliphatic hydrocarbon group include a bicyclo[4.3.0]nonanyl group, a decahydronaphthalenyl group, a tricyclo[5.2.1.0]nonan ... ２，６ ]decanyl group, bornyl group, isobornyl group, norbornyl group, adamantyl group, noradamantyl group, 1,7,7-trimethyltricyclo[2.2.1.0 ２，６]heptanyl group, 3,7,7-trimethylbicyclo[4.1.0]heptanyl group, and groups having a steroid skeleton. Of these, norbornyl group, adamantyl group, and noradamantyl group are preferred. Examples of aromatic hydrocarbon groups include phenyl group and naphthyl group. Examples of heterocyclic groups include groups containing a lactone skeleton.

[0030] The monovalent organic group represented by R may or may not have a substituent. The substituent is not particularly limited. Examples of the substituent include an alkyl group, an alicyclic group, an aryl group, an aralkyl group, a hydroxy group, a carbonyl group, a cyano group, a halogeno group, an alkoxycarbonyl group, and an alkylcarbonyloxy group. The monovalent organic group represented by R (preferably containing a cyclic skeleton) preferably has 5 to 30 carbon atoms, more preferably 6 to 25 carbon atoms, from the viewpoint of appropriate diffusibility of the generated acid.

[0031] In terms of the balance between the acid strength of the generated acid and the diffusibility of the generated acid, R １ and R ２ It is preferred that one of these is a fluorine atom and the other is —OR.

[0032] In the acid generator represented by general formula (AG1), preferred structures on the anion side are listed below.

[0033]

[0034]

[0035] ・Cation side structure A ＋ The structure of the counter cation of A is not particularly limited as long as the acid generator represented by general formula (AG1) functions as an acid generator. ＋ By employing the above, for example, the sensitivity of the radiation-sensitive resin composition can be increased.

[0036] A ＋ is preferably an onium cation, and more preferably at least one cation selected from the group consisting of a sulfonium cation and an iodonium cation.

[0037] More specifically, A＋ is preferably represented by the following general formula (A1) or (A2).

[0038]

[0039] In general formula (A1), R ２１ , R ２２ and R ２３ R each independently represents an organic group. The number of carbon atoms in the organic group is usually 1 to 30, preferably 1 to 20. ２１ , R ２２ and R ２３ At least two of these may be bonded to form a ring structure. The ring structure may contain one or more atoms selected from the group consisting of an oxygen atom, a sulfur atom, an ester bond, an amide bond, and a carbonyl group. ２１ , R ２２ and R ２３ A preferred example of the group formed by bonding at least two of the above is an alkylene group (e.g., a butylene group, a pentylene group). ２４ and R ２５ each independently represents an organic group, which usually has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.

[0040] R ２１ , R ２２ and R ２３ and R ２４ and R ２５ The organic group in can be an aryl group, an alkyl group, a cycloalkyl group, or the like. The aryl group is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure containing an oxygen atom, a nitrogen atom, a sulfur atom, or the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue, a furan residue, a thiophene residue, an indole residue, a benzofuran residue, and a benzothiophene residue. In general formula (A1), R ２１ , R ２２ and R ２３When two or more of R are aryl groups, the two or more aryl groups may be the same or different. ２４ and R ２５ When both are aryl groups, the two aryl groups may be the same or different. Examples of the alkyl group or cycloalkyl group include a linear or branched alkyl group having 1 to 15 carbon atoms and a cycloalkyl group having 3 to 15 carbon atoms. More specific examples include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

[0041] R ２１ , R ２２ and R ２３ and R ２４ and R ２５ The organic group constituting the formula (A1) may or may not have a substituent. Examples of the substituent include an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a halogeno group, a hydroxy group, and a phenylthio group. Preferred substituents are linear or branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, and linear, branched, or cyclic alkoxy groups having 1 to 12 carbon atoms, and more preferably alkyl groups having 1 to 4 carbon atoms and alkoxy groups having 1 to 4 carbon atoms. In the cation structure represented by general formula (A1), the substituent is R ２１ , R ２２ and R ２３ Of course, only one of R may be substituted, two may be substituted, or all three may be substituted. ２１ , R ２２ and R ２３ In the cation structure represented by general formula (A2), the substituent is R ２４ and R ２５ Of course, only one of R may be substituted, or two of R may be substituted. ２４ and R ２５ may not have a substituent.

[0042] R ２１ The total number of carbon atoms in R is not particularly limited, but is, for example, 3 to 20, preferably 5 to 18, more preferably 6 to 16, and even more preferably 6 to 12, from the viewpoint of the balance of various properties. ２２ and R ２３ and R ２４ and R ２５ The same applies to the total number of carbon atoms.

[0043] From the viewpoint of stability in the radiation-sensitive resin composition and radiation absorption, in the cation structure represented by general formula (A1), R ２１ , R ２２ and R ２３ At least one of R is preferably an aryl group. ２１ , R ２２ and R ２３ More preferably, at least three of R ２１ , R ２２ and R ２３ It is more preferable that all of R are aryl groups. ２４ and R ２５ Preferably, at least one of them is an aryl group, and more preferably, both of them are aryl groups.

[0044] A in general formula (AG1) ＋ Preferred examples of the structure of are shown below. In the following, "Ph" represents a phenyl group. In addition to the structures shown below, the cation structures of the acid generators exemplified in paragraphs 0221 to 0227 and 0241 to 0249 of JP-A No. 2002-341539 can also be used as the cation structures of A. ＋ It can be adopted as.

[0045]

[0046]

[0047] Preferable specific examples of the compound represented by formula (AG1) are shown below: In the following, "Me" represents a methyl group.

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080] The radiation-sensitive resin composition may contain only one acid generator represented by general formula (AG1), or may contain two or more. The amount of the acid generator represented by general formula (AG1) used may be appropriately adjusted taking into consideration sensitivity and other performance properties. The concentration of the acid generator represented by general formula (AG1) in the non-volatile components of the radiation-sensitive resin composition is typically 1 to 50% by mass, and preferably 2 to 40% by mass.

[0081] Hereinafter, a first embodiment and a second embodiment will be described as specific aspects of the radiation-sensitive resin composition.

[0082] Radiation-sensitive resin composition (first embodiment) The radiation-sensitive resin composition of the first embodiment contains an acid generator represented by the general formula (AG1) shown above and a resin that decomposes under the action of an acid to change its solubility in a developer. The acid generator represented by the general formula (AG1) has already been described in detail, and therefore will not be described again.

[0083] (Acid-decomposable resin) The radiation-sensitive resin composition of the first embodiment contains a resin that decomposes under the action of an acid, thereby changing its solubility in a developer. In this specification, the "resin that decomposes under the action of an acid, thereby changing its solubility in a developer" may be referred to as an "acid-decomposable resin".

[0084] The acid-decomposable resin typically has a group (hereinafter also referred to as "acid-decomposable group") in the main chain or side chain of the resin, or in both the main chain and the side chain, that decomposes under the action of an acid to generate a polar group such as an alkali-soluble group. Usually, the acid-decomposable resin is insoluble or hardly soluble in a developer before being decomposed under the action of an acid. The acid-decomposable group preferably has a structure in which a polar group such as an alkali-soluble group is protected by a group that decomposes and leaves under the action of an acid. Examples of polar groups include phenolic hydroxy groups, alcoholic hydroxy groups, carboxyl groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamide groups, sulfonylimide groups, (alkylsulfonyl)(alkylcarbonyl)methylene groups, (alkylsulfonyl)(alkylcarbonyl)imide groups, bis(alkylcarbonyl)methylene groups, bis(alkylcarbonyl)imide groups, bis(alkylsulfonyl)methylene groups, bis(alkylsulfonyl)imide groups, tris(alkylcarbonyl)methylene groups, tris(alkylsulfonyl)methylene groups, etc. Preferred polar groups include phenolic hydroxy groups, carboxyl groups, and fluorinated alcohol groups.

[0085] Preferred groups as the acid-decomposable group are those obtained by substituting a hydrogen atom of these polar groups (alkali-soluble groups, etc.) with a group that is cleaved by an acid. Examples of the group that is cleaved by an acid include -C(R ３６ ) (R ３７ ) (R ３８ ), -C(R ３６ ) (R ３７ ) (OR ３９ ), -C(R ０１ ) (R ０２ ) (OR ３９ In these general formulas, R ３６ ~R ３９ R each independently represents an alkyl group, a monocyclic or polycyclic alicyclic group, an aryl group, an aralkyl group, or an alkenyl group. ３６ and R ３７ may be bonded to each other to form a ring. ０１ ~R ０２ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group.

[0086] In the pattern formation method described below, when patterning is performed using light (wavelength 193 nm) emitted from an ArF excimer laser, the acid-decomposable resin is preferably a resin that is substantially free of aromatic structures such as benzene rings. This is because aromatic structures absorb light with a wavelength of 193 nm. Here, "substantially free of aromatic structures" means, for example, that structural units having aromatic structures account for 5 mol % or less of all structural units of the resin.

[0087] When patterning is performed using light (wavelength 193 nm) emitted from an ArF excimer laser, the acid-decomposable resin preferably contains a (meth)acrylic resin. In terms of etching resistance, the (meth)acrylic resin preferably contains an alicyclic skeleton.

[0088] The (meth)acrylic resin as the acid-decomposable resin preferably has (i) a structural unit having an acid-decomposable group, (ii) a structural unit having a lactone structure, (iii) a structural unit having a hydroxy group, or the like.

[0089] (i) Examples of the structural unit having an acid-decomposable group include a structural unit represented by the following general formula (U1).

[0090]

[0091] In general formula (U1), R Ａ is a hydrogen atom or a methyl group, and ALG is a group that is cleaved by an acid.

[0092] The acid-removable group of ALG is preferably the aforementioned —C(R ３６ ) (R ３７ ) (R ３８ ) can be mentioned.

[0093] The ratio of the structural unit having an acid-decomposable group in the (meth)acrylic resin is, for example, 10 to 90 mol %, preferably 20 to 80 mol %. The (meth)acrylic resin may have two or more structural units having an acid-decomposable group.

[0094] (ii) Examples of structural units having a lactone structure include structural units represented by the following general formula (U2).

[0095]

[0096] In general formula (U2), R Ａ represents a hydrogen atom or a methyl group, and Lc represents a group containing a lactone skeleton.

[0097] Examples of the lactone skeleton include a γ-butyrolactone skeleton and a norbornane lactone skeleton (norbornane 2,6-lactone skeleton).

[0098] The ratio of structural units having a lactone structure in the (meth)acrylic resin is, for example, 10 to 90 mol %, preferably 20 to 80 mol %. The (meth)acrylic resin may have two or more structural units having a lactone structure.

[0099] (iii) Examples of structural units having a hydroxy group include structural units represented by the following general formula (U3).

[0100]

[0101] In general formula (U3), R Ａ represents a hydrogen atom or a methyl group; Cyc represents a group in which n+1 hydrogen atoms have been removed from an alicyclic hydrocarbon; L represents a single bond or a divalent linking group; and n is 1 or 2.

[0102] Preferred examples of the alicyclic hydrocarbon constituting the skeleton of Cyc include adamantane and norbornane. When L is a divalent linking group, examples of L include a linear or branched alkylene group. L may be substituted with fluorine. Specifically, L is -C(CF ３ ) ２ -. When L is -C(CF ３ ) ２ When n is 2, the two Ls may be the same or different.

[0103] The ratio of structural units having a hydroxy group in the (meth)acrylic resin is, for example, 10 to 90 mol %, preferably 20 to 80 mol %. The (meth)acrylic resin may have structural units having two or more hydroxy groups.

[0104] The (meth)acrylic resin as the acid-decomposable resin may or may not have structural units other than the above (i) to (iii).

[0105] In addition to (meth)acrylic resins, polyhydroxystyrene resins can also be used as acid-decomposable resins. Polyhydroxystyrene resins are preferably used when patterning is performed using light (wavelength 248 nm) emitted from a KrF excimer laser, or when patterning is performed using EUV light or an electron beam. Specific examples of polyhydroxystyrene resins include (i) resins having a hydroxystyrene structural unit and a hydroxystyrene structural unit protected by an acid-decomposable group, and (ii) resins having a hydroxystyrene structural unit and a structural unit represented by the general formula (U1) shown above.

[0106] Calixarene resins can also be used as the acid-decomposable resin. Calixarene resins are also preferably used when patterning is performed using light (wavelength 248 nm) emitted from a KrF excimer laser, or when patterning is performed using EUV light or an electron beam. Specific examples of calixarene resins include (i) resins having a phenolic hydroxy group structural unit and a phenolic hydroxy group structural unit protected by an acid-decomposable group.

[0107] The weight-average molecular weight of the acid-decomposable resin is, for example, 1,000 to 100,000, and preferably 2,000 to 50,000. The dispersity (weight-average molecular weight / number-average molecular weight) of the acid-decomposable resin is, for example, 1.0 to 2.5, and preferably 1.0 to 2.0. The weight-average molecular weight and dispersity of the acid-decomposable resin can be determined, for example, by gel permeation chromatography using polystyrene as a standard substance.

[0108] The radiation-sensitive resin composition of the first embodiment may contain only one acid-decomposable resin, or may contain two or more acid-decomposable resins. The amount of the acid-decomposable resin is, for example, 30 to 99% by mass, and preferably 50 to 95% by mass, of the non-volatile components of the radiation-sensitive resin composition.

[0109] (Quencher) The radiation-sensitive resin composition of the first embodiment may preferably contain a quencher, i.e., a component having a function of deactivating the acid generated from the acid generator. Use of a quencher suppresses excessive movement of the acid in the resin film, leading to higher resolution and reduced line edge roughness.

[0110] The quencher may be, for example, a basic compound, specifically a nitrogen-containing basic compound. Specific examples of quenchers include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, and piperidine. Other examples include compounds having an imidazole structure, compounds having a diazabicyclo structure, compounds having an onium hydroxide structure, compounds having an onium carboxylate structure, trialkylamines, alkylamine derivatives, and aniline derivatives. Furthermore, compounds known as "photodecomposable bases" or "photodisintegrating bases" in the field of photoresists can also be used as quenchers.

[0111] When a quencher is used, only one quencher may be used, or two or more quenchers may be used. When a quencher is used, the amount thereof is, for example, 0.1 to 10% by mass, preferably 0.5 to 5% by mass, of the non-volatile components of the radiation-sensitive resin composition.

[0112] (Solvent) The radiation-sensitive resin composition of the first embodiment usually contains a solvent. In other words, the radiation-sensitive resin composition of the first embodiment usually contains the above-mentioned components dissolved or dispersed in a solvent.

[0113] From the viewpoint of the solubility and stability of the acid generator and the acid-decomposable resin, the solvent typically contains an organic solvent. From the same viewpoint, the solvent preferably does not contain water. However, a small amount of water unintentionally mixed in due to moisture in the air may be acceptable.

[0114] Specific examples of the organic solvent include ketones, alcohols, polyhydric alcohols and derivatives thereof, ethers, esters, aromatic solvents, and fluorine-based solvents.

[0115] Examples of ketones include acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl isoamyl ketone, methyl isobutyl ketone, methyl isopentyl ketone, and 2-heptanone.

[0116] Examples of alcohols include isopropanol, butanol, isobutanol, n-pentanol, isopentanol, tert-pentanol, 4-methyl-2-pentanol, 3-methyl-3-pentanol, 2,3-dimethyl-2-pentanol, n-hexanol, n-heptanol, 2-heptanol, n-octanol, n-decanol, s-amyl alcohol, t-amyl alcohol, isoamyl alcohol, 2-ethyl-1-butanol, lauryl alcohol, hexyldecanol, and oleyl alcohol.

[0117] Examples of polyhydric alcohols and derivatives thereof include ethylene glycol, ethylene glycol monoacetate, ethylene glycol dimethyl ether, diethylene glycol, diethylene glycol dimethyl ether, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate (PGMEA), monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, and monophenyl ether of dipropylene glycol or dipropylene glycol monoacetate.

[0118] Examples of ethers include diethyl ether, diisopropyl ether, tetrahydrofuran, dioxane, and anisole.

[0119] Examples of esters include methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, and γ-butyrolactone.

[0120] Examples of aromatic solvents include xylene and toluene.

[0121] Examples of fluorine-based solvents include chlorofluorocarbons, chlorofluorocarbon substitutes, perfluoro compounds, and hexafluoroisopropyl alcohol.

[0122] When a solvent is used, only one solvent may be used, or two or more solvents may be used. The amount of solvent used is, from the viewpoint of providing a film of a desired thickness, an amount such that the concentration of non-volatile components becomes, for example, 1 to 60% by mass, preferably 5 to 50% by mass.

[0123] (Other Optional Components) The radiation-sensitive resin composition of the first embodiment may or may not contain optional components other than those described above. Examples of optional components include acid generators other than those represented by general formula (AG1), surfactants (preferably fluorine-based), antioxidants, dyes, plasticizers, photosensitizers, light absorbers, and compounds that promote solubility in a developer (for example, low-molecular-weight phenolic compounds or carboxylic acids). Furthermore, when the radiation-sensitive resin composition of the first embodiment is applied to immersion exposure, a water-repellent polymer may be used. Fluorine-containing polymers and silicon-containing polymers are known as preferred water-repellent polymers.

[0124] <Radiation-Sensitive Resin Composition (Second Embodiment)> The radiation-sensitive resin composition of the second embodiment contains an acid generator represented by general formula (AG1) and a component that undergoes polymerization by the action of an acid, thereby changing its solubility in a developer. Specific aspects and preferred amounts of the acid generator represented by general formula (AG1) in the radiation-sensitive resin composition of the second embodiment are as described in the section <Radiation-Sensitive Resin Composition>.

[0125] A typical example of a component that undergoes an acid-induced increase in molecular weight and changes its solubility in a developer is a combination of an alkali-soluble resin and a crosslinker. The alkali-soluble resin is a resin that is soluble in an aqueous alkaline solution used as a developer, as described below, but is neither slightly soluble nor insoluble.

[0126] Examples of alkali-soluble resins include novolak resins, hydrogenated novolak resins, acetone-pyrogallol resins, o-polyhydroxystyrene, m-polyhydroxystyrene, p-polyhydroxystyrene, hydrogenated polyhydroxystyrene, halogen- or alkyl-substituted polyhydroxystyrene, hydroxystyrene-N-substituted maleimide copolymers, o / p- and m / p-hydroxystyrene copolymers, polyhydroxystyrene partially O-alkylated with respect to the hydroxyl groups (for example, 5 to 30 mol % O-methylated products, O Examples of the styrene-based copolymer include styrene-maleic anhydride copolymers, styrene-hydroxystyrene copolymers, α-methylstyrene-hydroxystyrene copolymers, carboxyl group-containing methacrylic resins and derivatives thereof, and polyvinyl alcohol derivatives.

[0127] Particularly preferred alkali-soluble resins are novolak resins, o-polyhydroxystyrene, m-polyhydroxystyrene, p-polyhydroxystyrene, alkyl-substituted polyhydroxystyrene, partially O-alkylated or O-acylated polyhydroxystyrene, styrene-hydroxystyrene copolymers, and α-methylstyrene-hydroxystyrene copolymers.

[0128] When an alkali-soluble resin is used, only one alkali-soluble resin may be used, or two or more alkali-soluble resins may be used.

[0129] The crosslinking agent is not particularly limited as long as it is a compound that crosslinks the alkali-soluble resin by the action of an acid. Specific examples of the crosslinking agent include the following (1) to (3). Specific compounds corresponding to these are described, for example, in paragraphs 0208 to 0209 of JP-A No. 2004-117688. (1) Hydroxymethyl, alkoxymethyl, and acyloxymethyl phenol derivatives (2) Compounds having an N-hydroxymethyl group, an N-alkoxymethyl group, or an N-acyloxymethyl group (3) Compounds having an epoxy group

[0130] When the crosslinking agent has an alkoxymethyl group, the number of carbon atoms in the alkoxymethyl group is preferably 6 or less. When the crosslinking agent has an acyloxymethyl group, the number of carbon atoms in the acyloxymethyl group is preferably 6 or less.

[0131] When a crosslinking agent is used, only one crosslinking agent may be used, or two or more crosslinking agents may be used.

[0132] The ratio of the alkali-soluble resin to the crosslinking agent may be adjusted appropriately in consideration of the balance of various properties. The amount of the crosslinking agent may be, for example, 5 to 50 parts by mass, specifically 10 to 40 parts by mass, per 100 parts by mass of the alkali-soluble resin.

[0133] The proportion of components that are polymerized by the action of an acid and whose solubility in a developer changes (typically, an alkali-soluble resin and a crosslinking agent) in the non-volatile components of the radiation-sensitive resin composition of the second embodiment is, for example, 50 to 95% by mass, and preferably 60 to 90% by mass.

[0134] The radiation-sensitive resin composition of the second embodiment may contain an acid generator represented by general formula (AG1), a component that undergoes the action of an acid to increase its molecular weight and change its solubility in a developer, and various additive components and solvents. Examples of the additive components include the quencher and other optional components described in the section <Radiation-Sensitive Resin Composition (First Embodiment)>. Specific aspects and amounts of the additive components and solvents used are as described in the section <Radiation-Sensitive Resin Composition (First Embodiment)>.

[0135] <Pattern Forming Method and Electronic Device Manufacturing Method> (Hereinafter, unless otherwise specified, the radiation-sensitive resin composition of the first embodiment and the radiation-sensitive resin composition of the second embodiment will be collectively referred to as the "radiation-sensitive resin composition.")

[0136] A pattern can be formed using the radiation-sensitive resin composition. Specifically, the pattern can be formed by forming a film using the radiation-sensitive resin composition, irradiating the film with radiation, and developing the irradiated film.

[0137] Furthermore, the formed pattern can be used as a mask for dry etching, ion implantation, metal sputtering, or metal plating to manufacture electronic devices.

[0138] The above-mentioned film formation, irradiation and development will be briefly explained below, along with other optional or incidental matters.

[0139] (Film formation) The substrate on which the film is formed is not particularly limited. Examples include glass substrates, silicon wafers, ceramic substrates, aluminum substrates, SiC wafers, GaN wafers, copper substrates, and copper-plated substrates. The substrate may be an unprocessed substrate or a substrate on which electrodes or elements are formed. From the viewpoint of preventing the irradiated light from being reflected by the substrate and deteriorating the resolution, it is preferable that an anti-reflection film is provided on the surface of the substrate.

[0140] The method for forming the film is not particularly limited. In the field of electronic device manufacturing, spin coating using a spinner is common, but other methods may also be used. For example, spray coating using a spray coater, dipping, printing, roll coating, inkjet method, etc. may also be used.

[0141] The radiation-sensitive resin composition coated on the substrate is typically dried by heat treatment. The heating temperature is usually 80 to 250°C, preferably 90 to 220°C. The heating time varies depending on the heating device, but when a hot plate is used, it is usually 30 to 300 seconds, preferably about 40 to 180 seconds, and when a hot air oven is used, it is usually 5 to 60 minutes, preferably about 10 to 30 minutes.

[0142] The thickness of the film is not particularly limited and may be adjusted appropriately depending on the application to be applied, the pattern to be finally obtained, etc. The film thickness is, for example, 5 to 500 nm, preferably 10 to 400 nm, and more preferably 15 to 300 nm. The film thickness can be adjusted by adjusting the concentration of non-volatile components in the radiation-sensitive resin composition, changing the coating method and coating conditions, etc.

[0143] (Radiation Irradiation) Radiation irradiation is usually carried out by exposing the film to radiation through an appropriate photomask. In cases where the beam diameter is small, such as in the case of electron beams, a photomask may not be used. The types of radiation are as described above. In the manufacture of electronic devices, light with a wavelength of 248 nm emitted from a KrF excimer laser, light with a wavelength of 193 nm emitted from an ArF excimer laser, extreme ultraviolet light (EUV light) with a wavelength of 13.5 nm, electron beams, and the like are commonly used. In particular, when irradiating a film with light with a wavelength of 193 nm emitted from an ArF excimer laser, immersion exposure can also be applied to increase resolution. In this case, a topcoat film may be provided for water repellency. Examples of devices for irradiating radiation include contact aligners, mirror projections, steppers, and scanners. The radiation dose can be adjusted appropriately depending on the amount of photoacid generator in the film, and is, for example, 1 to 500 mJ / cm. ２ That's about it.

[0144] If necessary, the film can be heated after exposure and before the development step (PEB: Post Exposure Bake). The temperature is, for example, 70 to 150°C, preferably 80 to 140°C. The time is usually 30 to 300 seconds, preferably 40 to 180 seconds, when using a hot plate, for example. By carrying out PEB, the solubilization or insolubilization reaction of the resin by the acid generated from the acid generator can be further promoted, and therefore further higher sensitivity can be expected.

[0145] (Development) A pattern can be obtained by developing the irradiated film with a developer. Development can be performed by, for example, an immersion method, a puddle method, or a rotary spray method.

[0146] As the developer, an alkaline aqueous solution is usually used. Specific examples of the alkaline aqueous solution include (i) inorganic alkaline aqueous solutions such as sodium hydroxide, sodium carbonate, sodium silicate, and ammonia; (ii) organic amine aqueous solutions such as ethylamine, diethylamine, triethylamine, and triethanolamine; and (iii) aqueous solutions of quaternary ammonium salts such as tetramethylammonium hydroxide and tetrabutylammonium hydroxide. As the developer, an aqueous tetramethylammonium hydroxide solution is particularly preferred. The concentration of tetramethylammonium hydroxide is preferably 0.1 to 10% by mass, and more preferably 0.5 to 5% by mass.

[0147] A positive pattern can usually be obtained by forming a film using the radiation-sensitive resin composition of the first embodiment, irradiating the film with radiation, and then developing the film with an alkaline aqueous solution. A negative pattern can usually be obtained by forming a film using the radiation-sensitive resin composition of the second embodiment, irradiating the film with radiation, and then developing the film with an alkaline aqueous solution.

[0148] On the other hand, it is also possible to use an organic solvent-based developer (a developer containing 90% or more by mass of organic solvent) instead of an alkaline aqueous solution as the developer. When a film is formed using the radiation-sensitive resin composition of the first embodiment, irradiated with radiation, and then developed with an organic solvent-based developer, a negative pattern, rather than a positive pattern, can usually be obtained. This is because the polarity of an alkaline aqueous solution and that of an organic solvent-based developer are opposite. When a film is formed using the radiation-sensitive resin composition of the second embodiment, irradiated with radiation, and then developed with an organic solvent-based developer, a negative pattern can usually be obtained, similar to development with an alkaline aqueous solution. Because the mechanism of insolubilization in the developer is high molecular weight, a negative pattern is usually formed whether the developer is an alkaline aqueous solution or an organic solvent-based developer. Development using an organic solvent-based developer is described in, for example, JP 2008-292975 A. As an organic solvent-based developer, butyl acetate developer is particularly well known.

[0149] A pattern can be formed by development, but after development, it is preferable to wash the pattern and the substrate with a rinse solution. When an alkaline aqueous solution is used as the developer, ultrapure water is suitable as the rinse solution. When an organic solvent-based developer is used as the developer, an organic solvent such as an alcohol-based solvent is suitable as the rinse solution.

[0150] The resulting pattern can be used, for example, in the manufacture of electronic devices, as a mask for dry etching, a mask for ion implantation processes, or a mask for metal sputtering or metal plating.

[0151] <Compound, preferably acid generator> Up to this point, embodiments of the novel technology of the present inventors have been described from the perspective of a "composition" and a pattern formation method and an electronic device manufacturing method using the same. Just to be clear, the novel technology of the present inventors can be understood not only as a composition, but also as a compound, preferably an acid generator. In other words, the compound (preferably an acid generator) represented by the above-described general formula (AG1) itself is novel and may be useful. When the compound represented by the above-described general formula (AG1) is an acid generator, an acid can be generated by applying an external stimulus to the compound (e.g., by irradiating it with radiation). The compound represented by the general formula (AG1), preferably an acid generator, has been fully explained in the section <Radiation-sensitive resin composition>, so a detailed explanation will be omitted.

[0152] <Method for producing a compound, preferably an acid generator or a precursor thereof> The compound represented by general formula (AG1) (preferably an acid generator or a precursor thereof) can be produced (synthesized) based on known techniques and methods in organic synthetic chemistry. Specific examples of production (synthesis) conditions and raw materials are described in the synthesis examples below. Incidentally, examples of the "precursor" of the acid generator represented by general formula (AG1) include compounds in which the cation moiety is a metal cation and which are substantially insensitive to radiation.

[0153] The production (synthesis) procedure will be briefly described below. The compound represented by general formula (AG1) can be produced (synthesized), for example, by the following procedure. In order to prevent unintended decomposition due to radiation, it is preferable that at least a part of the following procedure be carried out under conditions where the lighting is appropriately controlled.

[0154] (i) Methanetrisulfonic acid is synthesized by reacting fuming sulfuric acid with acetic anhydride.

[0155] (ii-1) Methanetrisulfonic acid is reacted with a fluorinating agent (preferably a nucleophilic fluorinating agent) and then with a metal fluoride such as potassium fluoride, thereby obtaining a compound (a precursor of an acid generator) represented by the following general formula (M-FSM):

[0156]

[0157] In the general formula (M-FSM), M ＋ is a metal cation. The metal cation is K ＋ , Na ＋ However, there is no particular limitation as long as the compound represented by general formula (M-FSM) is electrically neutral.

[0158] The fluorinating agent is not particularly limited, but a preferred fluorinating agent is FLUOLEAD (compound name: 4-tert-butyl-2,6-dimethylphenylsulfur trifluoride), a product name of UBE Corporation. Of course, other known fluorinating agents may be used as long as a compound represented by general formula (M-FSM) is obtained. The amount of the fluorinating agent used is preferably 3.0 to 8.0 equivalents. Examples of metal fluorides include potassium fluoride, as well as sodium fluoride. Of course, the metal fluoride is not particularly limited as long as a compound represented by general formula (M-FSM) is obtained. The amount of the metal fluoride used is preferably 3.0 to 20.0 equivalents. Incidentally, anhydrous hydrogen fluoride (AHF) or an organic hydrogen fluoride salt such as hydrogen fluoride pyridine or triethylamine trihydrofluoride may potentially be used instead of a metal fluoride. The reaction temperature here can be, for example, 10 to 50°C, and the reaction time can be, for example, 2 to 24 hours. Preferred examples of the solvent here include halogenated solvents such as dichloromethane and dichloroethane. Other solvents that can be used include heptane, toluene, tetrahydrofuran, and acetonitrile. Of course, solvents not listed here can also be used as long as they produce the compound represented by general formula (M-FSM).

[0159] (ii-2) Finally, in the compound represented by general formula (AG1), R １ and R ２In the case where at least one of the groups is -OR, the compound represented by the general formula (M-FSM) is reacted with the compound represented by R-OH. １ and R ２ In this case, a compound (a precursor of an acid generator) can be obtained in which at least one of the above is —OR.

[0160]

[0161] In general formula (ag1), M ＋ is a metal cation, R １ and R ２ are each independently a fluorine atom or —OR, and R is a monovalent organic group. ＋ , Na ＋ However, there are no particular limitations as long as the compound represented by general formula (M-FSM) is electrically neutral. Specific examples and preferred aspects of the monovalent organic group for R are as described in <Radiation-sensitive resin composition (first embodiment)>.

[0162] (iii) Metal cation M in the compound represented by general formula (M-FSM) or the compound represented by general formula (ag1) ＋ is replaced with an appropriate cation. In this way, a compound represented by general formula (AG1) (preferably an acid generator) can be obtained. As a specific example, a compound represented by general formula (ag1) and a compound represented by general formula A １ ＋ X － A compound represented by the following general formula (AG1-1) (preferably an acid generator) can be produced by reacting a compound represented by the following general formula A １ ＋ X － In this case, A １ ＋ is a sulfonium cation or an iodonium cation, and X － is a halide ion (preferably Cl － ,Br － , I －), sulfonate ion, sulfate ion, phosphate ion, hydroxide ion or carboxylate ion.

[0163]

[0164] In general formula (AG1-1), A １ ＋ is a sulfonium cation or an iodonium cation, R １ and R ２ are each independently a fluorine atom or —OR, and R is a monovalent organic group. １ ＋ Specific examples and preferred embodiments of the sulfonium cation or iodonium cation are as explained in the section <Radiation-sensitive resin composition>. The same applies to the structure of the sulfonium moiety in sulfonium chloride and the structure of the iodonium moiety in iodonium chloride. Specific examples and preferred embodiments of the monovalent organic group for R are as explained in the section <Radiation-sensitive resin composition>.

[0165] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention.

[0166] The embodiments of the present invention will be described in detail based on Examples and Comparative Examples. However, it should be noted that the present invention is not limited to the Examples.

[0167] Synthesis Examples Synthesis Example 1 Synthesis of methanetrisulfonic acid In a 0.5 L three-necked flask, 137 g of 30% oleum (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added. ３ The flask was charged with acetic anhydride (Fujifilm Wako Pure Chemical Industries, Ltd., 10 g, 98.3 mmol) and cooled in an ice bath. The temperature was then raised stepwise and the mixture was stirred overnight at 90°C. After cooling the reaction mixture to room temperature, it was filtered under reduced pressure using a polytetrafluoroethylene filter with a pore size of 1.0 μm, yielding 56.7 g of residue and 77.9 g of filtrate.１ Quantitative analysis by H-NMR revealed that the target compound was present in an amount of 118 mmol (quantitative yield 70%, internal standard: 1,4-bistrifluoromethylbenzene). The resulting residue was dispersed and washed sequentially with toluene (Fujifilm Wako Pure Chemical Industries, Ltd., 111 g x 2 times) and acetonitrile (Fujifilm Wako Pure Chemical Industries, Ltd., 81 g). The resulting crystals were then dried under conditions of a vacuum of less than 2 kPa and a bath temperature of 50°C. "Vacuum of less than 2 kPa" means that the absolute pressure was less than 2 kPa (hereinafter, the same applies to the same descriptions). In this manner, methanetrisulfonic acid (14.9 g, quantitative value 42.5 mmol, purity 66% by mass, yield 32%) was obtained.

[0168] The obtained methanetrisulfonic acid １ The results of the H-NMR analysis are shown below. １ H-NMR (DMSO, reference material: DMSO): 4.70 ppm (s, 1H, C-H)

[0169] For reference, the reaction scheme is shown below.

[0170]

[0171] Synthesis Example 2: Synthesis of K-FSM (The chemical structure of K-FSM is shown below.) In a 1 L jar made of PFA (perfluoroalkoxyalkane), methanetrisulfonic acid (10 g, 28.5 mmol, purity 73% by mass), FLUOLEAD ＴＭ (UBE, 44 g, 176 mmol, 6.2 equivalents) and methylene chloride (Fujifilm Wako Pure Chemical Industries, Ltd., 333 g) were added. The mixture was stirred at 40°C for 8.5 hours and then at room temperature overnight. Potassium fluoride (Fujifilm Wako Pure Chemical Industries, Ltd., 22.7 g, 390 mmol, 13.7 equivalents) was then added to the reaction solution in the jar and stirred at room temperature for 5.5 hours. After stirring, the reaction solution was filtered using a pressure filter (washing with methylene chloride, 25 g x 2). In this way, 39.4 g of residue (K-FSM quantitative value 6.4 g, 21.3 mmol, quantitative yield 75%) and 352 g of filtrate were obtained.

[0172] For reference, the reaction scheme is shown below.

[0173]

[0174] A 0.5 L three-necked flask was charged with 70.6 g of the combined filter cake (K-FSM quantitative value 13.0 g, 41.3 mmol) from another batch obtained by the same procedure, and ethyl methyl carbonate (160 g) and stirred at room temperature for 3 hours. After stirring, the reaction solution was filtered through a pressure filter (Kishida Chemical Co., Ltd., washed with 40 g of ethyl methyl carbonate). This yielded 77.6 g of filter cake and 185 g of filtrate. The filtrate was then subjected to reduced pressure distillation (vacuum degree <2 kPa, oil bath 55°C) to remove the solvent and dry. In this way, K-FSM (11.6 g, quantitative value 36.2 mmol, internal standard: trifluoromethylbenzene, purity 94% by mass, process yield 88%, overall yield 66%) was obtained, with the amount of KF as an impurity reduced.

[0175] The obtained K-FSM １９ The results of the F-NMR analysis are shown below. １９ F-NMR (CD ３ CN, standard substance: trifluoromethylbenzene): 70.2 ppm (s, 3F)

[0176] Synthesis Example 3: Synthesis of PAG-1 (The chemical structure of PAG-1 is shown below.) K-FSM (3.03 g, 10 mmol, purity 94% by mass), triphenylsulfonium chloride (TPSCl, manufactured by Tokyo Chemical Industry Co., Ltd., 2.98 g, 10 mmol, 1.06 equivalents), chloroform (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 11.15 g), and ion-exchanged water (12.18 g) were placed in a 200 mL three-necked recovery flask and stirred at room temperature for 4 hours. Thereafter, chloroform (10.36 g) and ion-exchanged water (12.98 g) were added and stirred for an additional 5 minutes. After stirring, the reaction solution was transferred to a 200 mL separatory funnel and allowed to settle for 10 minutes. The mixture was then separated into two layers, yielding 31.91 g of an aqueous layer and 22.08 g of an organic layer. Subsequently, ion-exchanged water (27.50 g) was added to the obtained organic layer, and the mixture was stirred for 10 minutes and allowed to settle in a 200 mL separatory funnel for 10 minutes. Thereafter, the mixture was separated into two layers, yielding 27.49 g of an aqueous layer and 20.68 g of an organic layer. Furthermore, ion-exchanged water (26.47 g) was added to the obtained organic layer, and the mixture was stirred for 10 minutes and allowed to settle in a 200 mL separatory funnel for 10 minutes. Thereafter, the mixture was separated into two layers, yielding 27.03 g of an aqueous layer and 19.46 g of an organic layer. The organic layer was evaporated under reduced pressure (vacuum degree <2 kPa, oil bath 50°C) and dried. In this manner, PAG-1 (5.46 g, quantitative value 9.38 mmol, purity 99% by mass, yield 93%) was obtained.

[0177] The results of nuclear magnetic resonance analysis of the obtained PAG-1 are shown below. １ H-NMR (CDCl ３ , Reference material: TMS): 7.63-7.82ppm (m, 15H) １９ F-NMR (CDCl ３ , Reference material: CF ３ CH ２ OH): 71.7ppm (s, 3F)

[0178] For reference, the reaction scheme is shown below.

[0179]

[0180] Synthesis Example 4 Synthesis of PAG-2 K-FSM (1.06 g, 3.3 mmol, purity 94% by mass), 1-adamantanemethanol (Tokyo Chemical Industry Co., Ltd., 0.55 g, 3.3 mmol, 1.0 equivalent), sodium hydride (Fujifilm Wako Pure Chemical Industries, Ltd., 60 wt % (mineral oil product), 0.27 g, 6.6 mmol, 2.0 equivalent), and acetonitrile (Fujifilm Wako Pure Chemical Industries, Ltd., 50.28 g) were placed in a 200 mL three-neck flask and stirred at room temperature for 20 hours. After stirring, the reaction solution was filtered through a syringe filter (pore size 0.22 μm, made of PTFE (polytetrafluoroethylene)), yielding 52 g of filtrate. The filtrate was added dropwise to a 1 M aqueous hydrochloric acid solution (30.33 g) and stirred at room temperature for 30 minutes. Heptane (66.60 g) was then added to the filtrate and stirred for 15 minutes. The reaction mixture was then transferred to a 500 mL separatory funnel and allowed to settle for 5 minutes. This allowed the mixture to separate into three layers, yielding 67.01 g of a heptane layer, 43.47 g of an acetonitrile layer, and 35.26 g of an aqueous layer.

[0181] Triphenylsulfonium chloride (TPSCl, manufactured by Tokyo Chemical Industry Co., Ltd., 1.51 g, 5.0 mmol, 1.5 equivalents), chloroform (152.76 g), and ion-exchanged water (100.01 g) were added to the resulting acetonitrile layer and aqueous layer, and the mixture was stirred for 1 hour. After stirring, the reaction mixture was transferred to a 500 mL separatory funnel and allowed to settle for 5 minutes. The mixture was then separated into two layers, yielding 141.52 g of an aqueous layer and 188.47 g of an organic layer. Subsequently, ion-exchanged water (101.14 g) was added to the resulting organic layer, and the mixture was stirred for 10 minutes and allowed to settle in a 500 mL separatory funnel for 5 minutes. Subsequently, the mixture was separated into two layers, yielding 110.81 g of an aqueous layer and 175.89 g of an organic layer. Subsequently, ion-exchanged water (99.59 g) was added to the resulting organic layer, and the mixture was stirred for 10 minutes and allowed to settle in a 500 mL separatory funnel for 5 minutes. The mixture was then separated into two layers, yielding 106.15 g of an aqueous layer and 166.85 g of an organic layer. The organic layer was evaporated under reduced pressure (vacuum degree <2 kPa, oil bath 50°C) and dried. In this way, PAG-2 (1.92 g, quantitative value 2.84 mmol, purity 97% by mass, yield 85%) was obtained.

[0182] The results of nuclear magnetic resonance analysis of the obtained PAG-2 are shown below.１ H-NMR (CDCl ３ , Reference material: TMS): 1.58-1.96ppm (m, 15H), 3.78ppm (s, 2H), 7.63-7.82ppm (m, 15H) １９ F-NMR (CDCl ３ , Reference material: CF ３ CH ２ OH): 72.1ppm (s, 2F)

[0183] For reference, the scheme of the above reaction is shown below: In the following, Ad represents an adamantyl group.

[0184]

[0185] Synthesis Example 5: Synthesis of PAG-3 (for comparison) Potassium tris(trifluoromethanesulfonyl)methanide (Tokyo Chemical Industry Co., Ltd., 4.6 g, 10 mmol, purity 98 wt%), triphenylsulfonium chloride (TPSCl, Tokyo Chemical Industry Co., Ltd., 2.98 g, 10 mmol, 1.06 equivalents), chloroform (Fujifilm Wako Pure Chemical Industries, Ltd., 11.15 g), and ion-exchanged water (12.18 g) were placed in a 200 mL three-necked recovery flask and stirred at room temperature for 4 hours. Subsequently, chloroform (10.36 g) and ion-exchanged water (12.98 g) were added and stirred for an additional 5 minutes. After stirring, the reaction solution was transferred to a 200 mL separatory funnel and allowed to settle for 10 minutes. The mixture was then separated into two layers, yielding 31.91 g of an aqueous layer and 22.08 g of an organic layer. Subsequently, ion-exchanged water (27.50 g) was added to the obtained organic layer, and the mixture was stirred for 10 minutes and allowed to settle in a 200 mL separatory funnel for 10 minutes. Thereafter, the mixture was separated into two layers, yielding 27.49 g of an aqueous layer and 20.68 g of an organic layer. Furthermore, ion-exchanged water (26.47 g) was added to the obtained organic layer, and the mixture was stirred for 10 minutes and allowed to settle in a 200 mL separatory funnel for 10 minutes. Thereafter, the mixture was separated into two layers, yielding 27.03 g of an aqueous layer and 19.46 g of an organic layer. The organic layer was evaporated under reduced pressure (vacuum degree <2 kPa, oil bath 50°C) and dried. In this manner, PAG-3 (6.11 g, quantitative value 9.0 mmol, purity 99% by mass, yield 90%) was obtained.

[0186] The results of nuclear magnetic resonance analysis of the obtained PAG-3 are shown below.１ H-NMR (DMSO, reference material: TMS): 7.67-7.85ppm (m, 15H) １９ F-NMR (DMSO, reference material: CF ３ -Ph): -77.2ppm (s, 9F)

[0187] For reference, the reaction scheme is shown below.

[0188]

[0189] [Preparation of Comparative Acid Generator PAG-4] As a comparative acid generator, acid generator PAG-4 manufactured by Central Glass Co., Ltd. and having the following chemical structure was prepared: In the following chemical formula, Ad represents an adamantyl group.

[0190] Synthesis Example 6: Synthesis of TBPDPS-Cl A 200 mL three-neck flask was charged with magnesium (cuttings) (2.64 g, 0.1 mol, manufactured by Kanto Chemical Co., Ltd.). A stirrer tip was placed in the flask, and the mixture was stirred overnight under a nitrogen atmosphere. This scraped off the oxide film on the magnesium surface, activating it. Subsequently, dehydrated THF (tetrahydrofuran, 80 ml, manufactured by Kanto Chemical Co., Ltd.) was added to the flask, and the temperature was raised to 40°C. Subsequently, 1-bromo-4-tert-butylbenzene (21.3 g, 0.1 mol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added intermittently over 3 hours, followed by stirring at 50°C for 3 hours. Complete disappearance of 1-bromo-4-tert-butylbenzene was confirmed by gas chromatography, and the mixture was then cooled to room temperature. In this manner, a THF solution of 4-tert-butylbenzene magnesium bromide was obtained.

[0191] Meanwhile, diphenyl sulfoxide (20.3 g, 0.1 mol, manufactured by Tokyo Chemical Industry Co., Ltd.), dehydrated THF (100 mL, manufactured by Kanto Chemical Co., Ltd.), and chlorotrimethylsilane (14.1 g, 0.13 mol, manufactured by Tokyo Chemical Industry Co., Ltd.) were added to a 500 mL three-neck flask and cooled to 0°C. The previously synthesized THF solution of 4-tert-butylbenzene magnesium bromide was added dropwise over 1 hour while maintaining the total internal temperature at 20°C or below. Thereafter, the disappearance of the diphenyl sulfoxide peak was confirmed by HPLC while stirring at 20°C. Thereafter, 15% by mass hydrochloric acid (200 mL) was added to terminate (deactivate) the reaction.

[0192] After the reaction was completed, 300 mL of heptane was added to the solution, which was then stirred and separated into two layers. The lower layer (aqueous layer) was then recovered, and 100 mL of IPE (isopropyl ether) was added, followed by stirring and separation into two layers, and the aqueous layer was recovered. In this way, an aqueous solution containing 4-t-butylphenyldiphenylsulfonium chloride (TBPDPS-Cl) was obtained with a solid content of 30.1 g and a yield of 85%.

[0193] Synthesis Example 7 Synthesis of MOPDPS-Cl The same procedure as in Synthesis Example 6 was carried out, except that 1-bromo-4-tert-butylbenzene was replaced with 4-bromoanisole (a product of Tokyo Chemical Industry Co., Ltd.), thereby obtaining an aqueous solution containing 4-methoxyphenyldiphenylsulfonium chloride (MOPDPS-Cl).

[0194] Synthesis Example 8 Synthesis of FPDPS-Cl The same procedure as in Synthesis Example 6 was carried out, except that 1-bromo-4-tert-butylbenzene was replaced with 4-bromofluorobenzene (a product of Tokyo Chemical Industry Co., Ltd.), thereby obtaining an aqueous solution containing 4-fluorophenyldiphenylsulfonium chloride (FPDPS-Cl).

[0195] Synthesis Example 9 Synthesis of bissulfonium chloride (1) The same procedure as in Synthesis Example 6 was carried out, except that 1-bromo-4-tert-butylbenzene was replaced with bis(4-bromophenyl)sulfide (a product of Tokyo Chemical Industry Co., Ltd.), thereby obtaining an aqueous solution containing (thiodi-4,1-phenylene)bis(diphenylsulfonium) dichloride.

[0196] The structures of the compounds obtained in the above Synthesis Examples 6 to 9 are shown below.

[0197]

[0198] Synthesis Example 10: Synthesis of PAG-5 PAG-5 was obtained by the same procedure as in Synthesis Example 4, except that 2-adamantanol (a product of Tokyo Chemical Industry Co., Ltd.) was used instead of 1-adamantanemethanol. Synthesis Example 11: Synthesis of PAG-6 PAG-6 was obtained by the same procedure as in Synthesis Example 4, except that 5-hydroxy-2-adamantanone (a product of Tokyo Chemical Industry Co., Ltd.) was used instead of 1-adamantanemethanol.

[0199] Synthesis Example 12: Synthesis of PAG-7 PAG-7 was obtained in the same manner as in Synthesis Example 4, except that 1-adamantanemethanol was replaced with 5-hydroxynorbornane-2,6-lactone (Tokyo Chemical Industry Co., Ltd.).

[0200] Synthesis Example 13: Synthesis of PAG-8 PAG-8 was obtained in the same manner as in Synthesis Example 4, except that 1-adamantanemethanol was replaced with exo-norborneol (a product of Tokyo Chemical Industry Co., Ltd.).

[0201] Synthesis Example 14: Synthesis of PAG-9 PAG-9 was obtained in the same manner as in Synthesis Example 4, except that triphenylsulfonium chloride (TPSCl) was changed to diphenyliodonium chloride (DPICl) (product of Tokyo Chemical Industry Co., Ltd.).

[0202] Synthesis Example 15 Synthesis of PAG-10 PAG-10 was obtained by the same procedure as in Synthesis Example 4, except that triphenylsulfonium chloride (TPSCl) was changed to bis(4-tert-butylphenyl)iodonium chloride (BTPICl) (product of Tokyo Chemical Industry Co., Ltd.).

[0203] Synthesis Example 16 Synthesis of PAG-11 PAG-11 was obtained by the same procedure as in Synthesis Example 4, except that triphenylsulfonium chloride (TPSCl) was changed to 4-t-butylphenyldiphenylsulfonium chloride synthesized in Synthesis Example 6.

[0204] Synthesis Example 17 Synthesis of PAG-12 PAG-12 was obtained by the same procedure as in Synthesis Example 4, except that the triphenylsulfonium chloride (TPSCl) in Synthesis Example 4 was changed to 4-methoxyphenyldiphenylsulfonium chloride synthesized in Synthesis Example 7.

[0205] Synthesis Example 18 Synthesis of PAG-13 PAG-13 was obtained by the same procedure as in Synthesis Example 4, except that the triphenylsulfonium chloride (TPSCl) in Synthesis Example 4 was changed to 4-fluorophenyldiphenylsulfonium chloride synthesized in Synthesis Example 8.

[0206] Synthesis Example 19 Synthesis of PAG-14 PAG-14 was obtained by the same procedure as in Synthesis Example 4, except that the triphenylsulfonium chloride (TPSCl) in Synthesis Example 4 was changed to (thiodi-4,1-phenylene)bis(diphenylsulfonium) dichloride synthesized in Synthesis Example 9.

[0207] The chemical structures of PAG-5 to PAG-14 are shown below, where Ad is an abbreviation for adamantyl group.

[0208]

[0209] <Evaluation: Storage Stability> 0.5 g of each of the above PAG-1 to PAG-14 was dissolved in deuterated chloroform (4.5 g) to prepare a solution with an acid generator concentration of 10% by mass. １９ F-NMR was measured. The NMR charts immediately after preparation and after 24 hours of storage at room temperature were compared and evaluated as follows: - If a new peak was observed in the NMR chart after 24 hours of storage at room temperature: poor - If no new peak was observed in the NMR chart after 24 hours of storage at room temperature: good

[0210] <Evaluation: Alkaline Hydrolysis> 0.5 g of each of the above PAG-1 to PAG-14 was mixed with 2.38 mass % aqueous tetramethylammonium solution (0.1 g) and deuterated chloroform (4.5 g) to prepare a solution with an acid generator concentration of 10 mass %. The resulting solution was stirred at room temperature for 24 hours. After stirring, the solution was １９F-NMR was measured. The results were compared with the NMR chart immediately after preparation measured in the above <Evaluation: Storage stability> and evaluated as follows: - When the peaks attributable to fluorine in the acid generator completely disappeared and a new peak not attributable to fluorine in the acid generator was observed: Good - When both the peaks attributable to fluorine in the acid generator and a new peak not attributable to fluorine in the acid generator were observed: Fair - When no new peak not attributable to fluorine in the acid generator was observed: Poor

[0211] The evaluation results are summarized in the table below.

[0212]

[0213] The above results indicate that the acid generator represented by general formula (AG1) is stable in organic solvents but is easily decomposed by the action of alkali. This means that when a radiation-sensitive resin composition containing the acid generator represented by general formula (AG1) is used to form a pattern on a substrate by exposure to light and alkali development treatment, residues derived from the acid generator are less likely to remain on the substrate, and therefore the amount of fluorine atoms remaining on the substrate can be reduced.

[0214] Preparation of Radiation-Sensitive Resin Composition (for ArF Exposure) PAG-1 (0.8 g), Resin A (10 g), triethylamine (0.1 g) as a quencher, and propylene glycol monomethyl ether acetate (50 g) and γ-butyrolactone (50 g) as solvents were thoroughly mixed to prepare a solution. Resin A is a random copolymer. This solution was filtered through a Teflon (registered trademark) filter with a pore size of 0.2 μm. In this manner, a radiation-sensitive resin composition (Example 2-1) was prepared. Furthermore, radiation-sensitive resin compositions (Example 2-2, Comparative Examples 2-1 to 2-2, and Examples 2-3 to 2-12) were prepared using PAG-2 to PAG-14 instead of PAG-1. For the correspondence between the example and comparative example numbers and the acid generators used, please refer to the table below.

[0215]

[0216] In Resin A, x = 0.4, y = 0.4, and z = 0.2. Resin A has a weight average molecular weight Mw of 10,600 and a dispersity Mw / Mn of 1.75.

[0217] <Evaluation of Radiation-Sensitive Resin Composition (ArF Exposure)> An antireflective film ARC29A manufactured by Nissan Chemical Industries, Ltd. was applied to a silicon wafer having a diameter of 4 inches using a spin coater and baked at 200°C for 60 seconds to form an antireflective film with a thickness of 84 nm. A radiation-sensitive resin composition was then applied thereon using a spin coater and baked at 120°C for 60 seconds to form a resin film with a thickness of 280 nm. Using an exposure device: ArFES-3500LDLS (manufactured by Litho Tech Japan Co., Ltd.), the formed resin film was irradiated with light having a wavelength of 193 nm. No photomask was used during this process (solid exposure). After irradiation, the silicon wafer with the resin film formed thereon was baked at 120°C for 60 seconds. The silicon wafer was then developed using a 2.38% by mass aqueous solution of tetramethylammonium hydroxide at 23°C for 60 seconds. The developed silicon wafer was rinsed with pure water.

[0218] The thickness of the resin film remaining after the rinsing was measured using an ellipsometer M2000 (manufactured by J.A. Woollam Japan). The exposure dose at which the film thickness was reduced by 90% or more was defined as the minimum required exposure dose (E ｔｈ ) and evaluated the sensitivity.

[0219] <Evaluation of Radiation-Sensitive Resin Composition (Evaluation of Fluorine Residual on Substrate)> The radiation-sensitive resin composition was applied to a silicon wafer having a diameter of 4 inches using a spin coater and baked at 120°C for 60 seconds. In this way, a resin film having a thickness of 280 nm was formed. The formed resin film was irradiated with light having a wavelength of 193 nm using an exposure device: ArFES-3500LDLS (manufactured by Litho Tech Japan Co., Ltd.). No photomask was used at this time (solid exposure). The exposure dose was 10 mJ / cm. ２ (E ｔｈThe irradiation dose was set to be sufficiently greater than the irradiation dose at 120°C for 60 seconds. The silicon wafer on which the resin film was formed was then baked at 120°C for 60 seconds. Then, development was performed using a 2.38 mass% aqueous solution of tetramethylammonium hydroxide at 23°C for 60 seconds. After development, the silicon wafer was rinsed with pure water.

[0220] The fluorine content of the rinsed silicon wafers was measured using X-ray photoelectron spectroscopy (XPS) to compare the F1s spectrum of the wafer surface. The XPS measurement was performed using a JEOL JPS-9000MA. The measurement was performed at 10 different locations, and the average intensity at the 10 locations was used to evaluate the level of residual fluorine. The smaller the value obtained here, the less fluorine-containing components remained on the wafer.

[0221] The results of the evaluation (ArF exposure) using the radiation-sensitive resin composition are summarized in the table below.

[0222]

[0223] <Preparation of Radiation-Sensitive Resin Composition (for KrF Exposure)> The above PAG-1 (0.8 g), Resin B (10 g) below, triethylamine (0.1 g) as a quencher, and propylene glycol monomethyl ether acetate (50 g) and γ-butyrolactone (50 g) as solvents were thoroughly mixed to prepare a solution. Resin B is a random copolymer. This solution was filtered through a Teflon (registered trademark) filter with a pore size of 0.2 μm. In this manner, a radiation-sensitive resin composition (Example 3-1) was prepared. Furthermore, radiation-sensitive resin compositions (Example 3-2, Comparative Example 3-1) were prepared using PAG-2 and PAG-4 instead of PAG-1.

[0224]

[0225] In Resin B, x=0.3 and y=0.7. Resin A has a weight average molecular weight Mw of 11,600 and a dispersity Mw / Mn of 1.95.

[0226] <Preparation of Radiation-Sensitive Resin Composition (for KrF Exposure)> The above PAG-1 (0.8 g), Karexarene resin (10 g), triethylamine (0.1 g) as a quencher, and propylene glycol monomethyl ether acetate (50 g) and γ-butyrolactone (50 g) as solvents were thoroughly mixed to form a solution. This solution was filtered through a Teflon (registered trademark) filter with a pore size of 0.2 μm. In this manner, a radiation-sensitive resin composition (Example 4-1) was prepared. The Karexarene resin was prepared with reference to J. Photopolym. Sci. Technol., Vol. 25, 5, 2012, pp. 587-592. The weight-average molecular weight (Mw) was 3,300, the polydispersity (Mw / Mn) was 1.1, and the protection rate of phenolic hydroxy groups was 60%. Furthermore, radiation-sensitive resin compositions (Example 4-2, Comparative Example 4-1) were prepared using PAG-2 and PAG-4 instead of PAG-1.

[0227] <Evaluation of Radiation-Sensitive Resin Composition (KrF Exposure)> A radiation-sensitive resin composition (for KrF exposure) was applied to a silicon wafer with a diameter of 4 inches using a spin coater and baked at 100°C for 60 seconds to form a resin film with a thickness of 280 nm. Using an exposure device: VUVES-4700i (manufactured by Litho Tech Japan Co., Ltd.), the formed resin film was irradiated with light having a wavelength of 248 nm. No photomask was used during this process (solid exposure). After irradiation, the silicon wafer with the resin film formed thereon was baked at 120°C for 60 seconds. The silicon wafer was then developed using a 2.38% by mass aqueous solution of tetramethylammonium hydroxide at 23°C for 60 seconds. After development, the silicon wafer was rinsed with pure water.

[0228] The thickness of the resin film remaining after the rinsing was measured using an ellipsometer M2000 (manufactured by J.A. Woollam Japan). The exposure dose at which the film thickness was reduced by 90% or more was defined as the minimum required exposure dose (E ｔｈ ) and evaluated the sensitivity.

[0229] <Evaluation of Radiation-Sensitive Resin Composition (Evaluation of Fluorine Residual on Substrate)> A radiation-sensitive resin composition (for KrF exposure) was applied to a silicon wafer with a diameter of 4 inches using a spin coater and baked at 100°C for 60 seconds. In this way, a resin film with a thickness of 280 nm was formed. Using an exposure device: VUVES-4700i (manufactured by Litho Tech Japan Co., Ltd.), the formed resin film was irradiated with light having a wavelength of 248 nm. No photomask was used at this time (solid exposure). The exposure dose was 10 mJ / cm. ２ (E ｔｈ The irradiation dose was set to be sufficiently greater than the irradiation dose at 120°C for 60 seconds. The silicon wafer on which the resin film was formed was then baked at 120°C for 60 seconds. Then, development was performed using a 2.38 mass% aqueous solution of tetramethylammonium hydroxide at 23°C for 60 seconds. After development, the silicon wafer was rinsed with pure water.

[0230] The fluorine content of the rinsed silicon wafers was measured using X-ray photoelectron spectroscopy (XPS) to compare the F1s spectrum of the wafer surface. The XPS measurement was performed using a JEOL JPS-9000MA. The measurement was performed at 10 different locations, and the average intensity at the 10 locations was used to evaluate the level of residual fluorine. The smaller the value obtained here, the less fluorine-containing components remained on the wafer.

[0231] The results of the evaluation (KrF exposure) using the radiation-sensitive resin composition are summarized in the table below.

[0232]

[0233] The results shown in Tables 2 and 3 suggest the following. (i) The sensitivity of radiation-sensitive resin compositions containing acid generators (PAG-1, PAG-2, PAG-5 to PAG-14) corresponding to general formula (AG1) was comparable to that of radiation-sensitive resin compositions containing conventional acid generators (PAG-3 and PAG-4). This is thought to be because PAG-1, PAG-2, and PAG-5 to PAG-14 have an electron-withdrawing fluorosulfonyl structure, which ensures that the acid strength of the generated acid is sufficiently strong. (ii) When a radiation-sensitive resin composition containing an acid generator corresponding to general formula (AG1) was used in a lithography process including a development process using an aqueous alkaline solution, it was possible to suppress the residue of fluorine-containing components on the substrate. This is thought to be due to the acid generated from PAG-1, PAG-2, and PAG-5 to PAG-14 being hydrolyzed by the alkaline component. (iii) In the radiation-sensitive resin compositions of Examples 2-1 to 12, 3-1, 3-2, 4-1, and 4-2, including PAG-1, PAG-2, and PAG-5 to PAG-14, the acid generator contained fluorine atoms to enhance sensitivity, but the residual fluorine atoms on the substrate after alkali development treatment were suppressed. This overcomes the conventional trade-off. (iv) As shown in Table 3, even in KrF exposure (wavelength 248 nm), the sensitivity of the radiation-sensitive resin compositions containing the acid generators (PAG-1 and PAG-2) corresponding to general formula (AG1) was comparable to the sensitivity of the radiation-sensitive resin composition containing the conventional acid generator (PAG-4). These results indicate that the compound (acid generator) represented by general formula (AG1) can also be used in KrF resists. Furthermore, since there is a correlation between KrF sensitivity and EUV sensitivity (Journal of Photopolymer Science and Technology Volume 37, Number 1 (2024) 89-93), the present invention is also expected to be applicable to EUV resist applications.

[0234] Incidentally, this specification does not describe any examples of the radiation-sensitive resin composition of the second embodiment. However, considering the above-mentioned mechanism that the acid generated from the acid generator is decomposed by an alkaline developer, thereby suppressing the residue of a fluorine-containing component, and the results supporting this mechanism (see the above <Evaluation: Alkaline Hydrolysis>), it is believed that the radiation-sensitive resin composition of the second embodiment can also suppress the residue of a fluorine-containing component.

[0235] This application claims priority based on Japanese Patent Application No. 2023-202572, filed November 30, 2023, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A radiation-sensitive resin composition comprising an acid generator represented by the following general formula (AG1): In general formula (AG1), R １ and R ２ are each independently a fluorine atom or -OR, R is a monovalent organic group, ＋ is the counter cation.

2. The radiation-sensitive resin composition according to claim 1, comprising a resin that is decomposed by the action of an acid and has a change in solubility in a developer.

3. The radiation-sensitive resin composition according to claim 1, which contains a component that undergoes molecular weight increase under the action of an acid and changes its solubility in a developer.

4. The radiation-sensitive resin composition according to any one of claims 1 to 3, １ and R ２ and 5. The radiation-sensitive resin composition according to any one of claims 1 to 3, １ and R ２ one of the radicals is a fluorine atom, and the other is --OR.

6. The radiation-sensitive resin composition according to any one of claims 1 to 3, １ and R ２ at least one of the following is -OR, and R contains a cyclic skeleton.

7. The radiation-sensitive resin composition according to any one of claims 1 to 3, ＋ is at least one cation selected from the group consisting of a sulfonium cation and an iodonium cation.

8. A pattern forming method comprising: forming a film using the radiation-sensitive resin composition according to any one of claims 1 to 3; irradiating the film with radiation; and developing the irradiated film.

9. A method for manufacturing an electronic device, comprising the pattern formation method according to claim 8.

10. An acid generator represented by the following general formula (AG1): In general formula (AG1), R １ and R ２ are each independently a fluorine atom or -OR, R is a monovalent organic group, ＋ is the counter cation.

11. The acid generator according to claim 10, comprising R １ and R ２ and 12. The acid generator according to claim 10 or 11, comprising R １ and R ２ one of which is a fluorine atom and the other is --OR.

13. The acid generator according to claim 10, comprising R １ and R ２ At least one of the following is -OR, and R contains a cyclic skeleton.

14. The acid generator according to claim 10 or 11, ＋ is at least one cation selected from the group consisting of a sulfonium cation and an iodonium cation.

15. A compound represented by the following general formula (ag1) and a compound represented by the following general formula A １ ＋ X － (A １ ＋ is a sulfonium cation or an iodonium cation, and X － is a halide ion, a sulfonate ion, a sulfate ion, a phosphate ion, a hydroxide ion, or a carboxylate ion), to produce a compound represented by general formula (AG1-1): In general formula (ag1), M ＋ is a metal cation; R １ and R ２ each independently represents a fluorine atom or -OR, and R represents a monovalent organic group. In general formula (AG1-1), A １ ＋ The definition of is as above, and R １ and R ２ each independently represents a fluorine atom or -OR, and R represents a monovalent organic group.

16. A method for producing a compound, comprising a step of reacting a compound represented by the following general formula (M-FSM) with a compound represented by R-OH, where R is a monovalent organic group, to obtain a compound represented by the following general formula (ag1). In the general formula (M-FSM), M ＋ is a metal cation. In general formula (ag1), M ＋ is a metal cation; R １ and R ２ are each independently a fluorine atom or -OR, where R １ and R ２ At least one of the groups is -OR, where R is a monovalent organic group.

17. A compound represented by the following general formula (AG1): In general formula (AG1), R １ and R ２ each independently represents a fluorine atom or -OR, R represents a monovalent organic group, ＋ is the counter cation.

18. The compound according to claim 17, comprising R １ and R ２ A compound in which both are fluorine atoms.

19. A compound according to claim 17 or 18, comprising R １ and R ２ A compound in which one of the groups is a fluorine atom and the other is --OR.

20. The compound according to claim 17, comprising R １ and R ２ is -OR, and R contains a cyclic skeleton.

21. A compound according to claim 17 or 18, ＋ is at least one cation selected from the group consisting of a sulfonium cation and an iodonium cation.

22. A method for generating an acid, comprising irradiating the compound according to claim 17 or 18 with radiation to generate an acid.