TW202344499A - Compound, photosensitive composition and pattern forming method - Google Patents

Abstract

The compound of the present invention contains a heteropolyacid anion, a photoreactive cation represented by the following formula (1), and a hydrogen cation. The photosensitive composition of the present invention contains this compound. (In the above formula (1), R ¹ and R ² are each independently an optionally substituted chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or a carbon Aromatic groups with numbers 3 to 10; Q is a saturated aliphatic hydrocarbon chain or aromatic chain that may have a substituent; G is a substituent with a monovalent cation)

Description

Compound, photosensitive composition and pattern forming method

The present invention relates to a compound and a photosensitive composition that can be well used in ultralithographic processes or other photofabrication processes such as the manufacture of ultra-LSI (Large Scale Integration, large integrated circuit) or high-capacity microchips. . Furthermore, the present invention relates to a pattern forming method using the photosensitive composition. Specifically, the present invention relates to a compound and a photosensitive combination that can be favorably used for microprocessing of semiconductor devices using electron beams, X-rays, and EUV (Extreme Ultra Violet, extreme ultraviolet) light (wavelength: around 13 nm). object, and a pattern forming method using the photosensitive composition.

Previously, in the manufacturing process of semiconductor components such as IC (Integrated Circuit) or LSI, the photolithography method using a photoresist composition was used for microfabrication. In semiconductor photolithography technology, according to Moore's law, as semiconductor elements become miniaturized, circuit patterns become smaller, and further miniaturization is expected.

The composition of the photolithography method can be roughly divided into: the short-wavelength light source of the exposure device, and the photoresist that receives the short-wavelength light and reacts. For photoresist, high resolution, low roughness, and high sensitivity are all required. It is believed that the conventional photoresist containing a photoacid generator, called a chemically amplified type, will cause a decrease in resolution due to the diffusion of acid, and thus cannot cope with ultra-fine patterns.

Therefore, in recent years, non-chemically amplified photoresists mainly composed of compounds containing metal elements such as Zn and Sn have been proposed, and next-generation exposure devices using EUV (extreme ultraviolet) light to form fine patterns have been reported.

Regarding the chemical amplification type photoresist, it has been known that if it contains a polyoxyacid and a polymer, it functions as a chemical amplification type photoresist (Patent Documents 1 and 2). Furthermore, it is reported that a polyoxyacid having an acrylic substituent is synthesized with a polymer to form a polymer that functions as a photoresist (Non-Patent Document 1).

Patent Document 3 reports an example of using a heteropolyacid as a negative photoresist. Prior technical literature patent documents

Patent Document 1: U.S. Patent No. 5178989 Specification Patent Document 2: International Publication No. 2016/190261 Patent Document 3: International Publication No. 2007/148566 non-patent literature

Non-patent literature 1: Vishwanath Kalyani et al. Chem.Eur. J. 2015, 21, 2250-2258 http://dx.doi.org/10.1002/chem.201405369.

[Problem to be solved by the invention]

In photolithography methods, especially semiconductor photolithography technology, there is a demand for a photosensitive composition and a pattern forming method that can achieve further miniaturization of circuit patterns.

An object of the present invention is to provide a high-sensitivity, high-resolution compound and photosensitive composition that meet the requirements for miniaturization of circuit patterns, and a pattern forming method using the photosensitive composition. [Technical means to solve problems]

The present inventors discovered that a heteropolyacid containing a cation having a specific photoreactive substituent functions well as a photoresist for ultrafine patterns. Specifically, it is possible to conduct electron beam (EB) drawing experiments, and the result is that a photoresist with a fine pattern of hp 50 nm L&S (1:1) and very small roughness can be formed. The gist of the present invention is as follows.

[1] A compound containing a heteropolyacid anion, a photoreactive cation represented by the following formula (1), and a hydrogen cation.

[Chemical 1]

(In the above formula (1), R ¹ and R ² are each independently an optionally substituted chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or a carbon Aromatic groups with numbers 3 to 10; Q is a saturated aliphatic hydrocarbon chain or aromatic chain that may have a substituent; G is a substituent with a monovalent cation)

[2] The compound described in [1], which has a molecular weight of 110 to 500.

[3] The compound according to [1] or [2], wherein the heteropolyacid anion is selected from the group consisting of phosphotungstate anion, silinotungstate anion, phosphomolybdate anion, phosphotungstomolybdate anion and phosphovanadomolybdate anion One or more than two anions.

[4] The compound as described in any one of [1] to [3], wherein R ¹ and R ² in the above formula (1) are each independently adjacent to the nitrogen atom in the above formula (1). The carbon atom is a chain saturated aliphatic hydrocarbon group of secondary or tertiary carbon atoms.

[5] The compound according to any one of [1] to [4], wherein Q in the above formula (1) is a phenylene group which may have a substituent.

[6] The compound according to any one of [1] to [5], wherein G in the above formula (1) is an ammonium cation, a sulfonium cation or a phosphonium cation.

[7] A photosensitive composition containing the compound described in any one of [1] to [6].

[8] A photosensitive composition containing the compound described in any one of [1] to [6] and an organic solvent.

[9] A photosensitive composition containing the compound according to any one of [1] to [6] and a photoacid generator that generates acid by the action of chemical radiation.

[10] The photosensitive composition according to any one of [7] to [9], which is for chemical radiation with a wavelength of 6.5 to 13.5 nm.

[11] A pattern forming method, which includes the steps of: forming a photosensitive layer on a substrate using the photosensitive composition according to any one of [7] to [10]; and irradiating a predetermined area of the photosensitive layer Pattern exposure is performed using chemical radiation; and a developer is used to develop the exposed photosensitive layer to selectively remove the exposed or unexposed portions of the photosensitive layer.

[12] The pattern forming method according to [11], wherein the developer is an organic solvent with a solubility parameter (SP value) of 7.5 to 11. [Effects of the invention]

The compound and photosensitive composition of the present invention have high sensitivity and high resolution, and can simultaneously satisfy high sensitivity, high resolution, good pattern shape and reproducibility, and good line width roughness in ultra-fine areas. Here, the so-called line width roughness refers to the fact that the edge of the interface between the photoresist pattern and the substrate changes irregularly in the direction perpendicular to the line direction due to the characteristics of the photoresist. Therefore, the edge appears when the pattern is viewed from directly above. Bump. The unevenness is transferred through the etching step using the photoresist as a mask, which degrades the electrical characteristics and therefore reduces the yield. According to the pattern forming method of the present invention using the photosensitive composition of the present invention, it is possible to fully respond to the demand for further miniaturization of circuit patterns in recent years.

Hereinafter, embodiments of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be implemented with various changes within the scope of the spirit. In this specification, when the expression "～" is used, it is used to include the numerical or physical values described before and after it. In addition, the numerical values or physical values described as the upper limit and the lower limit are used with a meaning that includes the value.

[Photosensitive compound] The compound of the present invention is characterized by containing a heteropolyacid anion, a photoreactive cation represented by the following formula (1) (hereinafter, sometimes referred to as "photoreactive cation (1)"), and a hydrogen cation.

[Chemicalization 2]

(In the above formula (1), R ¹ and R ² are each independently an optionally substituted chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or a carbon Aromatic groups with numbers 3 to 10; Q is a saturated aliphatic hydrocarbon chain or aromatic chain that may have a substituent; G is a substituent with a monovalent cation)

[Mechanism] The compound of the present invention functions as a non-chemically amplified low-molecular photoresist by decomposing the photoreactive cation represented by the above formula (1) after exposure. The compound of the present invention has a smaller molecular size and is believed to be able to form finer patterns.

[Heteropolyacid anion] The heteropolyacid anion of the present invention is not particularly limited as long as it is a small nanostructure with a diameter of 2 nm or less and the durability against dry etching gas can be improved by containing a metal element. Examples thereof include: phosphotungstate anion, silicotungstate anion, phosphomolybdate anion, phosphotungstomolybdate anion, phosphovanadomolybdate anion and the like. Among these, in terms of ease of synthesis and low cost, phosphotungstate anion, silitungstate anion, phosphomolybdate anion, phosphotungstomolybdate anion, and phosphovanadomolybdate anion are preferred, and silicon is more preferred. Tungstate anion. The compound of the present invention may contain only one type of these heteropolyacid anions, or may contain two or more types.

[Photoreactive cation (1)] The photoreactive cation (1) of the present invention is represented by the following formula (1).

[Chemical 3]

(In the above formula (1), R ¹ and R ² are each independently an optionally substituted chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or a carbon Aromatic groups with numbers 3 to 10; Q is a saturated aliphatic hydrocarbon chain or aromatic chain that may have a substituent; G is a substituent with a monovalent cation)

<R ¹ , R ² > As R ¹ and R ² in the formula (1), the chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms is preferably a linear or branched alkyl group having 1 to 5 carbon atoms. , more preferably branched alkyl. Specific examples include branched alkyl groups such as isopropyl, isobutyl, tert-butyl, and isopentyl.

The chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms in R ¹ and R ² is preferably a linear or branched chain unsaturated aliphatic hydrocarbon group having 3 to 5 carbon atoms, and more preferably a branched alkene group. base. Specific examples include isopropenyl, isobutenyl, isopentenyl, isohexenyl, and the like.

The aromatic group having 3 to 10 carbon atoms in R ¹ and R ² may be an aromatic heterocyclic group or an aromatic hydrocarbon group. Moreover, it may be a monocyclic group or a condensed cyclic group. Examples of the aromatic heterocyclic group include aromatic heterocyclic groups having 3 to 9 carbon atoms. Specific examples include pyrrolyl, thienyl, furyl, pyridyl, pyrrolopyrrolyl, and thienothiophene. base, cyclopentethienyl, indolyl, benzothiadiazolyl, benzopyrrolyl, etc. Examples of the aromatic hydrocarbon group include aromatic hydrocarbon groups having 6 to 10 carbon atoms, and specific examples include phenyl, naphthyl, and the like. They may have substituents such as methyl group and ethyl group.

From the perspective of improving the electron donating property of the nitrogen atom, decomposition reaction between the carbonyl group and the nitrogen atom is easy to occur during exposure, and the reaction sensitivity is improved, R ¹ and R ² are preferably each independently the same as in formula (1) The carbon atom adjacent to the nitrogen atom is a chain saturated aliphatic hydrocarbon group of secondary or tertiary carbon atoms. Examples of such chain saturated aliphatic hydrocarbon groups include branched alkyl groups having 3 to 5 carbon atoms, and isopropyl groups are particularly preferred.

Examples of substituents that the chain saturated aliphatic hydrocarbon group, chain unsaturated aliphatic hydrocarbon group or aromatic group of R ¹ and R ² may have include those exemplified as the substituent group T below. The chain saturated aliphatic hydrocarbon group, chain unsaturated aliphatic hydrocarbon group or aromatic group of R ¹ and R ² may have only one of these substituents, or may have two or more identical or different substituents.

<Substituent group T> Examples of the substituent T include a hydroxyl group, a nitro group, a carboxyl group, a hydroxyl group, an alkoxy group, an amino group, a sulfonyl group, a phosphonic acid group, and a halogen group such as a fluorine, chlorine, or bromine group. For the aromatic group, an alkyl group can be exemplified as a substituent.

As a substituent that the chain saturated aliphatic hydrocarbon group, chain unsaturated aliphatic hydrocarbon group or aromatic group of R ¹ and R ² in the above substituent group T may have, preferred ones are hydroxyl group, alkoxy group, amino group, Nitro group, carboxyl group, acyl group, sulfonyl group, phosphonic acid group, more preferably amine group, alkoxy group and hydroxyl group. In the case of an aromatic group, an alkyl group is also preferred. From the viewpoint of ease of synthesis, it is preferable that the chain saturated aliphatic hydrocarbon group, chain unsaturated aliphatic hydrocarbon group or aromatic group of R ¹ and R ² has no substituent.

＜Q＞ Examples of the saturated aliphatic hydrocarbon chain of Q in formula (1) include an alkylene group having 1 to 20 carbon atoms.

The aromatic group of Q may be an aromatic heterocyclic group or an aromatic hydrocarbon group. Moreover, it may be a group based on a single ring or a group based on a condensed ring. Examples of the aromatic heterocyclic group include aromatic heterocyclic groups having 3 to 9 carbon atoms. Specific examples thereof include a pyrrolynylene group, a thienylene group, a furylynylene group, a pyridylynylene group, a pyrrolopyrlynylene group, and the like. Examples of the aromatic hydrocarbon group include aromatic hydrocarbon groups having 6 to 10 carbon atoms. Specific examples include phenylene group, naphthylene group, and the like.

Examples of substituents that the saturated aliphatic hydrocarbon chain or aromatic chain of Q may have include those selected from the above substituent T.

From the viewpoint of ease of synthesis, Q is preferably an extension that may have a substituent such as an alkyl group such as a methyl group, an ethyl group, or a propyl group, a hydroxyl group, a methoxy group, a nitro group, an amino group, a carboxyl group, or an ester group. Phenyl, preferably p-phenylene.

＜G＞ Examples of substituents having monovalent cations for G in formula (1) include ammonium cations, sulfonium cations, phosphonium cations, and the like. From the viewpoint of ease of synthesis, sulfonium cation is preferred. From the viewpoint of synthesis ease and ionicity, dimethylsulfonyl cation is more preferred. The ionicity tends to be stronger the smaller the organic group bonded to the sulfonium cation is.

<Hydrogen cation> The hydrogen cation is represented by H ⁺ . The charge of the compound of the present invention exists in a neutralized form by the heteropolyacid anion, the photoreactive cation (1) and the hydrogen cation.

[Molecular weight] The molecular weight of the compound of the present invention (the sum of the molecular weights of the heteropolyacid anion, the photoreactive cation (1) and the hydrogen cation) is preferably 1,000 to 5,000, more preferably 1,500 to 4,000, and still more preferably 2,500 to 4,000. If the molecular weight of the compound of the present invention is less than the above-mentioned upper limit, the volume will also be small, so it is expected that the roughness and resolution will be high. When the molecular weight of the compound of the present invention is not less than the above-mentioned lower limit, coating properties or etching resistance tend to be improved. Molecular weight is the target. This alone cannot determine the lithography characteristics, so it is not limited to this.

Here, the molecular weight of the compound of the present invention can be investigated, for example, by electrospray ionization mass spectrometry (ESI-MS), for example, by measuring the molecular weight of the cation and the anion. However, theoretically ESI-MS cannot determine the sum of molecular weights, but can only determine the individual molecular weights and ion valences of anions and cations. Therefore, first, the individual molecular weights of anions and cations are determined based on ESI-MS. Secondly, find the valence of the anion and the number of coordinations of the cation. Then, the molecular weights of the cations are accumulated based on the number of coordination points and summed up with the molecular weights of the anions, whereby the sum of the above molecular weights can be obtained.

Specifically, the compound of the present invention can be synthesized by the method described in the following examples.

[Photosensitive composition] The photosensitive composition of the present invention contains the compound of the present invention. The photosensitive composition of the present invention may contain only one type of the compound of the present invention, or may contain two or more types.

The content of the compound of the present invention in the photosensitive composition of the present invention is usually 30 to 100 mass %, preferably 40 to 100 mass %, and particularly preferably 30 to 100 mass % with respect to the total components of the photosensitive composition except the solvent. 50～100% by mass. If the content of the compound of the present invention in the photosensitive composition is more than the above lower limit, good exposure sensitivity can be obtained.

[Photoacid generator] The photosensitive composition of the present invention can also function by containing the compound of the present invention and a photoacid generator (hereinafter, sometimes simply referred to as a "photoacid generator") that generates acid by the action of chemical radiation. . Here, examples of chemical radiation include bright line spectrum of a mercury lamp, far ultraviolet rays represented by excimer laser, extreme ultraviolet rays (EUV light), X-rays, electron beams, and the like. From the viewpoint of resolution, chemical radiation with a smaller exposure wavelength is preferred, and EUV light that emits light with a wavelength of 6.5 to 13.5 nm is preferred.

The photoacid generator that generates acid by such chemical radiation is not particularly limited as long as it is a known one. The photoacid generator is preferably one that generates an organic acid by irradiating chemical radiation, such as at least one of sulfonic acid, bis(alkylsulfonyl)imide, and tris(alkylsulfonyl)methide. compound. More preferred photoacid generators include compounds represented by the following formulas (ZI), (ZII), and (ZIII).

[Chemical 4]

In the above formula (ZI), R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represent an organic group. The carbon number of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is generally 1 to 30, preferably 1 to 20.

Examples of the organic group of R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include an aryl group, an alkyl group, a cycloalkyl group and the like. The aryl group of R ₂₀₁ , R ₂₀₂ and R ₂₀₃ usually has 6 to 20 carbon atoms, preferably 6 to 10 carbon atoms, more preferably a phenyl group or a naphthyl group, and still more preferably a phenyl group. The aryl group may also be an aryl group having a heterocyclic structure having an oxygen atom, a nitrogen atom, a sulfur atom, or the like. Examples of the heterocyclic structure include pyrrole, furan, thiophene, indole, benzofuran, benzothiophene, and the like.

Preferable examples of the alkyl group and cycloalkyl group of R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include linear or branched alkyl groups having 1 to 10 carbon atoms, and cycloalkyl groups having 3 to 10 carbon atoms. More preferred examples of the alkyl group include 2-side oxyalkyl group and alkoxycarbonylmethyl group. As the cycloalkyl group, a 2-side oxycycloalkyl group is more preferably exemplified.

The 2-side oxyalkyl group may be either linear or branched, and a preferred example is a group having >C=O at the 2-position of the above-mentioned alkyl group. As for the 2-side oxycycloalkyl group, a preferred example is a group having >C=O at the 2-position of the above-mentioned cycloalkyl group.

R ₂₀₁ , R ₂₀₂ and R ₂₀₃ may be further substituted by a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, a nitro group, or the like. In addition, two of R ₂₀₁ to R ₂₀₃ may be bonded to form a ring structure (preferably a 3 to 15-membered ring), and the ring may also contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. . Examples of the group formed by bonding two of R ₂₀₁ to R ₂₀₃ include an alkylene group (eg, butylene group, pentylene group).

Z ^- represents a non-nucleophilic anion (anion with a significantly lower ability to initiate nucleophilic reactions).

Examples of non-nucleophilic anions include sulfonate anions (aliphatic sulfonate anions, aromatic sulfonate anions, camphorsulfonate anions, etc.), carboxylate anions (aliphatic carboxylate anions, aromatic carboxylate anions, etc.) , aralkylcarboxylate anion, etc.), sulfonyl imine anion, bis(alkylsulfonyl)imide anion, tri(alkylsulfonyl)methide anion, etc.

The aliphatic part in the aliphatic sulfonate anion and aliphatic carboxylate anion can be an alkyl group or a cycloalkyl group. Preferred examples of the aliphatic moiety include a linear or branched alkyl group having 1 to 30 carbon atoms and a cycloalkyl group having 3 to 30 carbon atoms.

Preferable examples of the aromatic group in the aromatic sulfonate anion and the aromatic carboxylate anion include an aryl group having 6 to 14 carbon atoms, such as phenyl, tolyl, naphthyl, and the like.

The alkyl group, cycloalkyl group and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion may also have substituents. Specific examples of the substituent include halogen atoms such as nitro group and fluorine atom, carboxyl group, hydroxyl group, amine group, cyano group, alkoxy group (preferably having 1 to 15 carbon atoms), and cycloalkyl group (preferably having 1 to 15 carbon atoms). Preferably, it is C3-15), aryl group (preferably C6-14), alkoxycarbonyl group (preferably C2-7), acyl group (preferably C2-12), Alkoxycarbonyloxy group (preferably having 2 to 7 carbon atoms), alkylthio group (preferably having 1 to 15 carbon atoms), alkylsulfonyl group (preferably having 1 to 15 carbon atoms), alkylsulfonyl group Aminosulfonyl group (preferably having 2 to 15 carbon atoms), aryloxysulfonyl group (preferably having 6 to 20 carbon atoms), alkyl aryloxysulfonyl group (preferably having 7 to 20 carbon atoms) ), cycloalkyl aryloxysulfonyl group (preferably having 10 to 20 carbon atoms), alkoxyalkoxy group (preferably having 5 to 20 carbon atoms), cycloalkylalkoxyalkoxy group (preferably having 5 to 20 carbon atoms) Preferably, the carbon number is 8 to 20), etc. The aryl group and ring structure each group has may further have an alkyl group (preferably having 1 to 15 carbon atoms) as a substituent.

The aralkyl group in the aralkylcarboxylate anion is preferably an aralkyl group having 6 to 12 carbon atoms. Examples thereof include benzyl, phenethyl, naphthylmethyl, naphthylethyl, and naphthyl. Butyl et al.

Examples of the sulfonimide anion include saccharin anion.

The alkyl group in the bis(alkylsulfonyl)imide anion and tris(alkylsulfonyl)methide anion is preferably an alkyl group having 1 to 5 carbon atoms. Examples of substituents for such alkyl groups include: halogen atoms, alkyl groups substituted with halogen atoms, alkoxy groups, alkylthio groups, alkoxysulfonyl groups, aryloxysulfonyl groups, and cycloalkylaryl groups. Oxysulfonyl group, etc. Among these, a fluorine atom or an alkyl group substituted with a fluorine atom is preferred. The alkyl groups in the bis(alkylsulfonyl)imide anion can also bond with each other to form a ring structure. By this, the acid strength increases.

Examples of other non-nucleophilic anions include phosphorus fluoride (for example, PF ₆ ^- ), boron fluoride (for example, BF ₄ ^- ), and antimony fluoride (for example, SbF ₆ ^- ).

As the non-nucleophilic anion, preferred are an aliphatic sulfonate anion in which at least the α-position of the sulfonic acid is substituted with a fluorine atom, an aromatic sulfonate anion in which a fluorine atom or a group having a fluorine atom is substituted, and an alkyl group is substituted by a fluorine atom. The bis(alkylsulfonyl)imide anion and the tri(alkylsulfonyl)methide anion where the alkyl group is substituted by a fluorine atom. As the non-nucleophilic anion, perfluoroaliphatic sulfonate anion (more preferably C4 to 8), benzenesulfonate anion having a fluorine atom, nonafluorobutanesulfonate anion, and perfluorobutanesulfonate anion are more preferred. Fluorooctanesulfonate anion, pentafluorobenzenesulfonate anion, 3,5-bis(trifluoromethyl)benzenesulfonate anion.

From the viewpoint of acid strength, it is preferable to increase the sensitivity when the pKa of the generated acid is -1 or less.

As the non-nucleophilic anion, an anion represented by the following formula (AN1) can also be exemplified as a preferred form.

[Chemistry 5]

In formula (AN1), Xf each independently represents a fluorine atom or an alkyl group substituted by at least one fluorine atom. ^RA and ^RB each independently represent a group selected from a hydrogen atom, a fluorine atom, and an alkyl group. When there are a plurality of RA ^{and RB} , they may be the same or different from each other. L represents a bivalent linking group, and when there are plural L's, they may be the same or different. A represents a group having a cyclic structure. x represents an integer from 1 to 20. y represents an integer from 0 to 10. z represents an integer from 0 to 10.

Formula (AN1) will be explained in more detail. The alkyl group in the alkyl group substituted with a fluorine atom of Xf preferably has 1 to 10 carbon atoms, and more preferably has 1 to 4 carbon atoms. The alkyl group substituted by a fluorine atom of Xf is preferably a perfluoroalkyl group. Xf is preferably a fluorine atom or a perfluoroalkyl group having 1 to 4 carbon atoms. Specific examples include: fluorine atom, CF ₃ , C ₂ F ₅ , C ₃ F ₇ , C ₄ F ₉ , C ₅ F ₁₁ , C ₆ F ₁₃ , C ₇ F ₁₅ , C ₈ F ₁₇ , CH ₂ CF ₃ , CH ₂ CH ₂ CF ₃ , CH ₂ C ₂ F ₅ , CH ₂ CH ₂ C ₂ F ₅ , CH ₂ C ₃ F ₇ , CH ₂ CH ₂ C ₃ F ₇ , CH ₂ C ₄ F ₉ , CH ₂ CH ₂ C ₄ F ₉ . Among them, a fluorine atom and CF ₃ are preferred. In particular, it is preferable that both Xf's are fluorine atoms.

The alkyl groups of ^RA and ^RB may have a substituent (preferably a fluorine atom), and preferably have 1 to 4 carbon atoms. More preferably, it is a perfluoroalkyl group having 1 to 4 carbon atoms. Specific examples of the substituted alkyl group of R ^A and R ^B include: CF ₃ , C ₂ F ₅ , C ₃ F ₇ , C ₄ F ₉ , C ₅ F ₁₁ , C ₆ F ₁₃ , C ₇ F ₁₅ , C ₈ F ₁₇ , CH ₂ CF ₃ , CH ₂ CH ₂ CF ₃ , CH ₂ C ₂ F ₅ , CH ₂ CH ₂ C ₂ F ₅ , CH ₂ C ₃ F ₇ , CH ₂ CH ₂ C ₃ F ₇ , CH ₂ C ₄ F ₉ , CH ₂ CH ₂ C ₄ F ₉ . Among them, CF ₃ is preferred.

As ^RA and ^RB , a fluorine atom or CF ₃ is preferred. x is preferably 1 to 10, more preferably 1 to 5. y is preferably 0 to 4, more preferably 0. z is preferably 0 to 5, more preferably 0 to 3.

The divalent linking group of L is not particularly limited, and examples thereof include: -COO-, -OCO-, -CO-, -O-, -S-, -SO-, -SO ₂ -, alkylene group, The cycloalkyl group, alkenylene group, or a linking group in which a plurality of these are connected is preferably a linking group with a total carbon number of 12 or less. Among them, -COO-, -OCO-, -CO-, -O-, and -SO ₂ - are preferred, and -COO-, -OCO-, and -SO ₂ - are more preferred.

The group having a cyclic structure of A is not particularly limited as long as it has a cyclic structure. Examples thereof include: alicyclic groups, aryl groups, and groups having a heterocyclic structure (not only those having aromatic properties are included) , also includes those that are not aromatic), etc.

As the alicyclic group, it can be a single ring or a polycyclic ring, preferably a monocyclic cycloalkyl group such as cyclopentyl, cyclohexyl, cyclooctyl, nordyl, tricyclodecyl, or tetracyclodecyl. , tetracyclododecyl, adamantyl and other polycyclic cycloalkyl groups. Among them, alicyclic groups with a larger structure and a carbon number of 7 or more, such as nordecyl, tricyclodecyl, tetracyclodecyl, tetracyclododecyl, and adamantyl, can inhibit the heating step after exposure. Diffusion in the film is better from the viewpoint of improving MEEF (Mask Error Enhancement Factor).

Examples of the aryl group include benzene ring, naphthalene ring, phenanthrene ring, and anthracene ring.

Examples of the group having a heterocyclic structure include a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, a dibenzothiophene ring, and a pyridine ring. Among them, furan ring, thiophene ring and pyridine ring are preferred.

The above-mentioned group having a cyclic structure may have a substituent. Examples of the substituent include an alkyl group (which may be linear, branched, or cyclic, preferably having 1 to 12 carbon atoms), an aryl group (preferably having 6 to 14 carbon atoms), A hydroxyl group, an alkoxy group (preferably having 1 to 12 carbon atoms), a urea group, a sulfonamide group (preferably having 0 to 12 carbon atoms), or an ester group, a amide group, or a urethane group, A thioether group or a sulfonate group (preferably having 1 to 12 carbon atoms), etc.

It is preferable that at least one of R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is an aryl group, and it is more preferable that all three of them are aryl groups. As the aryl group, in addition to phenyl group, naphthyl group, etc., heteroaryl groups such as indole residue and pyrrole residue may also be used. These aryl groups may further have a substituent. Examples of the substituent include halogen atoms such as nitro group and fluorine atom, carboxyl group, hydroxyl group, amine group, cyano group, alkoxy group (preferably carbon number 1 to 15), cycloalkyl group (preferably carbon number (number 3 to 15), aryl group (preferably carbon number 6 to 14), alkoxycarbonyl group (preferably carbon number 2 to 7), acyl group (preferably carbon number 2 to 12), alkoxy group Carbonyloxy group (preferably having 2 to 7 carbon atoms), etc., but are not limited thereto.

When two of R ₂₀₁ to R ₂₀₃ are bonded to form a ring structure, a structure represented by the following formula (A1) is preferred.

[Chemical 6]

In formula (A1), R ^1a to R ^13a each independently represent a hydrogen atom, a halogen atom, a nitro group or an organic group. It is preferable that 1 to 3 of R ^1a to R ^13a are not hydrogen atoms, and it is more preferable that any one of R ^9a to R ^13a is not a hydrogen atom. Za is a single bond or a two-valent linking group. X ^- has the same meaning as Z ^- in formula (ZI).

Specific examples of the case where R ^1a to R ^13a are not hydrogen atoms include: halogen atom, nitro group, linear, branched and cyclic alkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group, Cyano, carboxyl, alkoxy, aryloxy, silyloxy, heterocyclic oxy, acyloxy, amide methionyloxy, alkoxycarbonyloxy, aryloxycarbonyloxy, amine (including aniline), acylamino, aminocarbonylamino, alkoxycarbonylamino, aryloxycarbonylamino, aminesulfonamide, alkyl and arylsulfonamide, alkylthio, aromatic Thio group, heterocyclic thio group, alkyl and aryl sulfinyl group, alkyl and aryl sulfinyl group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, aminomethyl group, aryl group and heterocycle Azo group, phosphinylamine group, silyl group, urea group, and other well-known organic groups. When R ^1a to R ^13a are not hydrogen atoms, they are preferably linear, branched or cyclic alkyl groups substituted with hydroxyl groups.

Examples of the divalent linking group of Za include an alkylene group, an aryl group, a carbonyl group, a sulfonyl group, a carbonyloxy group, a carbonylamine group, a sulfonylamide group, -O-, -S-, and an amine. group, disulfide group, -(CH ₂ ) _n -CO-, -(CH ₂ ) _n -SO ₂ -, -CH=CH-, aminocarbonylamino group, aminosulfonylamine group, etc. (n is an integer from 1 to 3).

Preferable structures when at least one of R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is not an aryl group include paragraphs 0046 and 0047 of Japanese Patent Application Laid-Open No. 2004-233661 and Japanese Patent Application Laid-Open No. 2003-35948. Paragraphs 0040 to 0046 of the Publication No., compounds of formulas (I-1) to (I-70) exemplified in the specification of U.S. Patent Application Publication No. 2003/0224288A1, compounds of formulas exemplified in the specification of U.S. Patent Application Publication No. 2003/0077540A1 Cationic structures of compounds of (IA-1) to (IA-54), formulas (IB-1) to (IB-24), etc.

In formulas (ZII) and (ZIII), R ₂₀₄ to R ₂₀₇ each independently represent an aryl group, an alkyl group or a cycloalkyl group.

The aryl group, alkyl group and cycloalkyl group of R ₂₀₄ to R ₂₀₇ are the same as the aryl group, alkyl group and cycloalkyl group of R ₂₀₁ to R ₂₀₃ in the formula (ZI). The aryl group, alkyl group and cycloalkyl group of R ₂₀₄ to R ₂₀₇ may have a substituent. Examples of the substituent include those which may have an aryl group, an alkyl group, or a cycloalkyl group of R ₂₀₁ to R ₂₀₃ in the formula (ZI).

^Z- represents a non-nucleophilic anion, and examples thereof include the same non-nucleophilic anion as ^Z- in the formula (ZI).

As the photoacid generator, compounds represented by the following formulas (ZIV), (ZV), and (ZVI) can also be exemplified.

[Chemical 7]

In the formulas (ZIV) to (ZVI), Ar ₃ and Ar ₄ each independently represent an aryl group. R ₂₀₈ , R ₂₀₉ and R ₂₁₀ each independently represent an alkyl group, a cycloalkyl group or an aryl group. A represents an alkylene group, an alkenylene group or an aryl group.

Specific examples of the aryl groups of Ar ₃ , Ar ₄ , R ₂₀₈ , R ₂₀₉ and R ₂₁₀ include the same ones as the specific examples of the aryl groups of R ₂₀₁ , R ₂₀₂ and R ₂₀₃ in the above formula (ZI). . Specific examples of the alkyl group and cycloalkyl group of R ₂₀₈ , R ₂₀₉ and R ₂₁₀ include the specific examples of the alkyl group and cycloalkyl group of R ₂₀₁ , R ₂₀₂ and R ₂₀₃ in the above formula (ZI), respectively. Examples are the same.

Examples of the alkylene group of A include an alkylene group having 1 to 12 carbon atoms (for example, methylene, ethylidene, propylene, isopropyl, butylene, isobutyl, etc.). Examples of the alkenylene group of A include alkenylene groups having 2 to 12 carbon atoms (for example, ethynylene group, propenylene group, butenylene group, etc.). Examples of the aryl group of A include an aryl group having 6 to 10 carbon atoms (for example, a phenylene group, a tolylene group, a naphthylene group, etc.).

Particularly preferred examples of photoacid generators are given below.

[Chemical 8]

[Chemical 9]

[Chemical 10]

[Chemical 11]

[Chemical 12]

The photoacid generator can be used individually by 1 type or in combination of 2 or more types. When two or more types of photoacid generators are used in combination, for example, (1) two types of photoacid generators with different acid strengths are used in combination, (2) two types of photoacid generators that are different in size (molecular weight or carbon number) of the acid generated are used in combination. The situation of acid generator and other forms. Examples of the form of (1) include a combination of a sulfonic acid generator having fluorine and a tris(fluoroalkylsulfonyl)methide acid generator, a sulfonic acid generator having fluorine and a sulfonic acid generator not having fluorine. The combined use of sulfonic acid generators, the combined use of alkylsulfonic acid generators and arylsulfonic acid generators, etc. Examples of the form of (2) include the combined use of two different acid generators having 4 or more carbon atoms in the acid anion generated.

In particular, the photosensitive composition of the present invention is preferably a photosensitive composition used in response to chemical radiation. A photosensitive composition that reacts with chemical radiation is preferable because the development speed of the developing solution changes and a pattern can be formed after development for a certain period of time. As chemical radiation, smaller light wavelengths are preferred because higher resolution can be obtained. As chemical radiation, light with a wavelength of 6.5 to 13.5 nm, that is, EUV light, is preferred. That is, the photosensitive composition of the present invention is preferably a photosensitive composition that reacts with light having a wavelength of 6.5 to 13.5 nm.

In the photosensitive composition, the compound of the present invention can react by being exposed to light alone. When a photoacid generator is added, it cooperates with the compound of the present invention in the photosensitive composition to perform photosensitization, so the photosensitivity of the compound of the present invention can be improved. Therefore, when a photosensitive composition consisting only of the compound of the present invention has insufficient photosensitivity for required specifications, it is preferable to add a photoacid generator.

When the photosensitive composition of the present invention contains a photoacid generator, the content of the photoacid generator in the photosensitive composition of the present invention (the total amount when a plurality of species are used in combination) is based on the photosensitive combination. Based on the total components of the substance except the solvent, 0.1 to 30 mass % is preferred, 0.5 to 20 mass % is more preferred, and 1 to 15 mass % is more preferred. If the content of the photoacid generator in the photosensitive composition is more than the above-mentioned lower limit, the effect of improving photosensitivity can be obtained. If it is less than the above-mentioned upper limit, it is less likely to be affected by poor film-forming properties of the photoacid generator, so it is possible to obtain The compound of the present invention is preferred due to its good film-forming properties.

[Solvent] The photosensitive composition of the present invention usually contains a solvent for liquid preparation. The solvent for liquid preparation of the photosensitive composition is not particularly limited as long as it can dissolve each component. Examples of the solvent include alkylene glycol monoalkyl ether carboxylate (propylene glycol monomethyl ether acetate (PGMEA; 1-methoxy-2-ethyloxypropane), etc.), Alkyl glycol monoalkyl ether (propylene glycol monomethyl ether (PGME; 1-methoxy-2-propanol), etc.), alkyl lactate (ethyl lactate, methyl lactate, etc.), cyclic lactone ( γ-butyrolactone, etc., preferably having 4 to 10 carbon atoms), chain or cyclic ketones (2-heptanone, cyclohexanone, etc., preferably having 4 to 10 carbon atoms), alkyl carbonate ( Organic solvents such as ethylene carbonate, propylene carbonate, etc.), carboxylic acid alkyl esters (preferably butyl acetate and other alkyl acetates), alkoxy alkyl acetates (ethoxyethyl propionate), etc. . Examples of other solvents that can be used include organic solvents described in [0244] and onward of US Patent Application Publication No. 2008/0248425A1.

Preferred are alkylene glycol monoalkyl ether carboxylates and alkylene glycol monoalkyl ethers among the above.

These solvents can be used individually or in mixture of 2 or more types. When two or more types are mixed, it is preferable to mix a solvent having a hydroxyl group and a solvent not having a hydroxyl group. As the solvent having a hydroxyl group, alkylene glycol monoalkyl ether is preferred. As the solvent having no hydroxyl group, alkylene glycol monoalkyl ether carboxylate is preferred.

The content of the solvent in the total amount of the photosensitive composition of the present invention can be appropriately adjusted according to the thickness of the pattern film to be formed, and the like. The content of the solvent in the total amount of the photosensitive composition of the present invention is usually adjusted so that the total concentration of components other than the solvent in the photosensitive composition is 0.5 to 30% by mass, preferably 1.0 to 20% by mass. %, more preferably 1.5 to 10 mass %, further preferably 1.5 to 5 mass %.

[Surfactant] The photosensitive composition of the present invention preferably further contains a surfactant. As the surfactant, fluorine-based and/or silicone-based surfactants are preferred. Examples of surfactants that meet these criteria include: MEGAFAC F176 and MEGAFAC R08 manufactured by Dainippon Ink Chemical Industry Co., Ltd., PF656 and PF6320 manufactured by OMNOVA, Troysol S-366 and Sumitomo manufactured by Troy Chemical Co., Ltd. Fluorad FC430 manufactured by 3M Co., Ltd., polysiloxane polymer KP-341 manufactured by Shin-Etsu Chemical Industry Co., Ltd., etc. Furthermore, surfactants other than fluorine-based and/or silicone-based surfactants may also be used. Specific examples of other surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, and the like.

In addition, known surfactants can be used appropriately. Examples of surfactants that can be used include surfactants described in [0273] and onwards of US Patent Application Publication No. 2008/0248425A1.

The surfactant can be used alone, or two or more types can be used in combination. The content of the surfactant is preferably 0.0001 to 2 mass %, more preferably 0.001 to 1 mass %, based on the total components of the photosensitive composition except the solvent.

[Other additives] In addition to the components described above, the photosensitive composition of the present invention may also appropriately contain carboxylic acid, carboxylic acid onium salt, dissolution-inhibiting compounds with a molecular weight of 3000 or less as described in Proceeding of SPIE, 2724, 355 (1996), dyes, plastics, etc. Chemical agents, photosensitizers, light absorbers, antioxidants, etc. In particular, carboxylic acids can be advantageously used to enhance performance. As the carboxylic acid, aromatic carboxylic acids such as benzoic acid and naphthoic acid are preferred. The content of the carboxylic acid is preferably 0.01 to 10% by mass, more preferably 0.01 to 5% by mass, and still more preferably 0.01 to 3% by mass relative to the total of components other than the solvent in the photosensitive composition.

[Production method of photosensitive composition] The photosensitive composition of the present invention can be produced by dissolving the compound of the present invention and, if necessary, a photoacid generator or other components in a solvent for liquid preparation, and filtering with a filter if necessary. . The filter is preferably made of polytetrafluoroethylene, polyethylene, or nylon and has a pore size of 0.1 micron or less, more preferably 0.05 micron or less, and still more preferably 0.03 micron or less. It is estimated that when the compound of the present invention contained in the photosensitive composition is dissolved in a solvent for liquid preparation, the heteropolyacid anion, the photoreactive cation (1) and the hydrogen cation exist in the form of ions respectively.

[Pattern forming method] The pattern forming method of the present invention includes the following steps: using the photosensitive composition of the present invention to form a photosensitive layer on a substrate; irradiating a predetermined area of the photosensitive layer with chemical radiation to perform pattern exposure; and using a developer to expose the photosensitive layer. The photosensitive layer is subjected to a development process to selectively remove the exposed portion or the unexposed portion of the photosensitive layer.

[Steps for forming photosensitive layer] The photosensitive layer can be formed by applying the photosensitive composition of the present invention to a substrate (for example, coating (silica, silicon dioxide), and then dried at 50 to 150°C. At this time, commercially available inorganic or organic anti-reflective films can be used if necessary. It can also be used by coating an anti-reflective film on the resist base layer.

[Exposure steps] In the present invention, "exposure" includes not only exposure using mercury lamps, far ultraviolet rays represented by excimer lasers, X-rays, EUV light, etc., but also particle beams such as electron beams and ion beams, unless otherwise specified. The depiction performed is also included in the exposure. Exposure can be performed by irradiating chemical radiation to a predetermined area through a predetermined mask on the formed photosensitive layer to perform pattern exposure, or by irradiating an electron beam and drawing (directly) without passing through a mask. Drawing) for pattern exposure. The chemical radiation is not particularly limited, and examples thereof include KrF excimer laser, ArF excimer laser, EUV light, and electron beam, and EUV light and electron beam are preferred. As mentioned above, as the chemical radiation, EUV light that emits light with a wavelength of 6.5 to 13.5 nm is preferred.

After the above exposure, baking (heating) may or may not be performed before development. When baking (heating), the heating temperature is preferably 50 to 150°C, more preferably 60 to 150°C, and still more preferably 80 to 140°C. When baking (heating) is performed, the heating time is preferably 30 to 300 seconds, more preferably 30 to 180 seconds, and still more preferably 30 to 90 seconds. Heating can be performed by a mechanism provided with a common exposure and developing machine. Heating can also be performed using a heating plate or the like.

[Development step] After exposure, a developer is used for development to selectively remove the exposed or unexposed portions of the photosensitive layer.

＜Developer＞ As the developer, an organic solvent is preferably used, and an organic solvent having a vapor pressure of 5 kPa or less at 20° C. is more preferably 3 kPa or less, and particularly preferably 2 kPa or less. By setting the vapor pressure of the organic solvent to less than 5 kPa, the evaporation of the developer on the substrate or in the developer cup can be suppressed, and the temperature uniformity within the surface of the pattern forming substrate is improved, resulting in dimensional uniformity within the surface of the pattern forming substrate. Get better.

As the organic solvent used as a developer, various organic solvents can be widely used. For example, at least one solvent selected from the group consisting of ester solvents, ketone solvents, alcohol solvents, amide solvents, ether solvents, hydrocarbon solvents, and the like can be used. In particular, a developer containing at least one solvent selected from a ketone solvent, an ester solvent, an alcohol solvent, and an ether solvent is preferred.

Examples of the ester solvent include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, ethyl 3-ethoxypropionate, propylene glycol diacetate, and 3-acetate. Methoxybutyl, 3-methyl-3-methoxybutyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate and other carboxylic acids Alkyl ester solvent, propylene glycol monomethyl ether acetate (PGMEA; also known as 1-methoxy-2-ethyloxypropane), ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether ethyl acid esters, alkylene glycol monoalkyl ether carboxylate solvents such as diethylene glycol monoethyl ether acetate and propylene glycol monoethyl ether acetate. Among these, butyl acetate, amyl acetate, ethyl lactate, and propylene glycol monomethyl ether acetate are more preferred.

Examples of ketone solvents include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, and diisobutyl Ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, phenylacetone, methylethylketone, methylamylketone, methylisobutylketone, acetoacetone, acetoneacetone, ionone, Diacetone alcohol, acetyl methanol, acetophenone, methyl naphthyl ketone, isophorone, propylene carbonate, etc. Among these, alkyl ketone solvents such as methyl isobutyl ketone, methyl amyl ketone, cyclopentanone, and cyclohexanone are more preferred.

Examples of alcohol-based solvents include hexanol such as methanol, ethanol, n-propanol, isopropanol, n-butanol, second-butanol, third-butanol, isobutanol, n-hexanol, n-hexanol, etc. Heptanol, n-octanol and other octanols, n-decanol and other decanols and other alcohols, or ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2- Butanediol, 1,3-butanediol, 1,4-butanediol and other glycol solvents, ethylene glycol monomethyl ether, propylene glycol monomethyl ether (PGME; also known as 1-methoxy-2-propane alcohol), ethylene glycol monoethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, triethylene glycol monoethyl ether and other alkylene glycol monoalkyl ether solvents, methoxymethyl butanol, propylene glycol di Glycol ether solvents such as methyl ether, phenol solvents such as phenol and cresol, etc. Among these, 1-hexanol, 2-hexanol, 1-octanol, 2-ethylhexanol, propylene glycol monomethyl ether, and cresol are more preferred.

Examples of the amide-based solvent include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, and hexamethylphosphonamide. Amine, 1,3-dimethyl-2-imidazolidinone, etc.

Examples of the ether solvent include, in addition to the above-mentioned alkylene glycol monoalkyl ether solvent and glycol ether solvent, dihexane, tetrahydrofuran, tetrahydropyran, and the like.

Examples of the hydrocarbon-based solvent include aromatic hydrocarbon-based solvents such as toluene and xylene, and aliphatic hydrocarbon-based solvents such as pentane, hexane, octane, decane, and dodecane.

The developer preferably contains one selected from the group consisting of alkylene glycol monoalkyl ether carboxylate solvents, alkylene glycol monoalkyl ether solvents, carboxylic acid alkyl ester solvents, and alkyl ketone solvents. More than one solvent is preferably selected from the group consisting of propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl isobutyl ketone, methyl amyl ketone, cyclopentanone, cyclohexanone, ethyl lactate, and one or more solvents of butyl acetate.

As the developer, it is preferable to use at least one selected from the group consisting of an ester solvent having no hydroxyl group in the molecule, a ketone solvent having no hydroxyl group in the molecule, and an ether solvent having no hydroxyl group in the molecule. Organic solvent developer.

In addition, the organic solvent used as the developer in the present invention is preferably an organic solvent with a solubility parameter (SP value) of 7.5 to 11. If it is an organic solvent with a solubility parameter of 7.5 or above, the development speed of the dissolved part will be accelerated. An organic solvent with a solubility parameter of 11 or less is preferable because it can suppress the development speed of the pattern forming portion. The solubility parameter of the organic solvent of the developer is preferably 8 to 11.

In the present invention, the value of the solubility parameter (SP value) is calculated by the method proposed by Fedors et al. Specifically, the value was obtained with reference to "POLYMER ENGINEERING AND SCIENCE, FEBRUARY, 1974, Vol. 14, No. 2, ROBERT F. FEDORS. (pages 147 to 154)". The SP value is a physical property value determined by the content of the hydrophobic group or hydrophilic group in the molecule. When a mixed solvent is used, it refers to the value of the mixture.

Examples of organic solvents that satisfy the above SP value include: diethylene glycol monomethyl ether (SP value = 10.7), triethylene glycol monomethyl ether (SP value = 10.7), ethylene glycol monoisopropyl ether (SP value = 10.9), ethylene glycol monobutyl ether (SP value = 10.2), diethylene glycol monobutyl ether (SP value = 10.0), triethylene glycol monobutyl ether (SP value = 10.0), ethylene glycol monobutyl ether Isobutyl ether (SP value = 9.1), ethylene glycol monohexyl ether (SP value = 9.9), diethylene glycol monohexyl ether (SP value = 9.7), diethylene glycol mono2-ethylhexyl ether (SP Value = 9.3), ethylene glycol monoallyl ether (SP value = 10.8), ethylene glycol monophenyl ether (SP value = 10.8), ethylene glycol monobenzyl ether (SP value = 10.9), propylene glycol monomethyl ether ( SP value = 10.0), dipropylene glycol monomethyl ether (SP value = 9.7), tripropylene glycol monomethyl ether (SP value = 9.4), propylene glycol monopropyl ether (SP value = 9.6), dipropylene glycol monopropyl ether (SP value = 9.8), propylene glycol monobutyl ether (SP value = 9.0), dipropylene glycol monobutyl ether (SP value = 9.6), ethylene glycol monomethyl ether acetate (SP value = 10.0), ethylene glycol monoethyl ether acetate (SP value = 9.6), ethylene glycol monobutyl ether acetate (SP value = 8.9), diethylene glycol monoethyl ether acetate (SP value = 9.4), diethylene glycol monobutyl ether acetate ( SP value = 9.0), propylene glycol monomethyl ether acetate (SP value = 9.4), propylene glycol monoethyl ether acetate (SP value = 9.0), or dipropylene glycol monomethyl ether acetate (SP value = 9.2), etc.

The above-mentioned organic solvent may be mixed with a plurality of kinds, and may be mixed with solvents other than the above or water.

The concentration of the above-mentioned organic solvents in the developer (total when a plurality of solvents are mixed) is preferably 50 mass% or more, more preferably 70 mass% or more, and still more preferably 90 mass% or more. Particularly preferred is the case where it contains essentially only organic solvents. The case where it contains essentially only organic solvents includes the case where trace amounts of surfactants, antioxidants, stabilizers, defoaming agents, etc. are contained.

The water content in the developer is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and most preferably contains substantially no water. By setting the moisture content to 10% by mass or less, good development characteristics can be obtained.

An appropriate amount of surfactant may be added to the developer used in the present invention as needed. As the surfactant, the same ones as those described above as the surfactant used in the photosensitive composition of the present invention can be used. The usage amount of the surfactant is usually 0.001 to 5 mass %, preferably 0.005 to 2 mass %, and further preferably 0.01 to 0.5 mass % relative to the total amount of the developer.

＜Development method＞ As the development method, for example, the following methods 1) to 4) can be applied. 1) A method of immersing the substrate in a tank filled with developer for a certain period of time (immersion method) 2) A method of developing by placing the developer on the surface of the substrate using surface tension and allowing it to stand for a certain period of time (liquid coating method) 3) Method of spraying the developer onto the surface of the substrate (spray method) 4) A method in which the developer is applied from the nozzle at a certain speed and scanned on the substrate rotating at a certain speed while the developer is continuously applied (dynamic dispensing method)

After the development step, a step of replacing the solvent with another solvent and stopping the development can also be performed.

The development time is preferably a time to fully dissolve the compound of the present invention in the photosensitive layer of the unexposed part or the exposed part, and is generally preferably 10 to 300 seconds, more preferably 20 to 120 seconds. The temperature of the developer is preferably 0 to 50°C, more preferably 15 to 35°C. The amount of developer can be adjusted appropriately according to the development method.

[rinsing step] In the pattern forming method of the present invention, after the development step, a step of cleaning using a rinse solution containing an organic solvent may also be included.

＜Rinsing fluid＞ The organic solvent used in the rinse liquid preferably has a vapor pressure of 0.05 kPa to 5 kPa at 20°C, more preferably 0.1 kPa to 5 kPa, and further preferably 0.12 kPa to 3 kPa. By setting the vapor pressure of the organic solvent used in the rinsing liquid to 0.05 kPa or more and 5 kPa or less, the temperature uniformity within the wafer surface is improved, thereby suppressing swelling caused by the penetration of the rinsing liquid, and improving the dimensional uniformity within the wafer surface. Get better.

As the above-mentioned rinse liquid, various organic solvents can be used, but for the compounds of the present invention such as compound (1), it is preferable to use a solvent containing a hydrocarbon solvent, a ketone solvent, an ester solvent, an alcohol solvent, and an amide. It is a rinse liquid of at least one organic solvent or water among solvents and ether solvents.

More preferably, after development, a washing step is performed using a rinse solution containing at least one organic solvent selected from a ketone solvent, an ester solvent, an alcohol solvent, an amide solvent, and a hydrocarbon solvent. Still more preferably, after development, a step of cleaning using a rinse solution containing at least one organic solvent selected from the group consisting of alcoholic solvents and hydrocarbon solvents is performed.

Specific examples of ketone-based solvents, ester-based solvents, alcohol-based solvents, amide-based solvents, ether-based solvents, and hydrocarbon-based solvents used as rinse solutions are the same as those described for the above-mentioned developer. It is particularly preferable to use a rinse liquid containing at least one organic solvent selected from the group consisting of monohydric alcohol solvents and hydrocarbon solvents.

Here, examples of the monohydric alcohol-based solvent used in the rinse step after development include linear, branched, and cyclic monohydric alcohols. Specifically, 1-butanol, 2-butanol, 3-methyl-1-butanol, tert-butanol, isopropanol, cyclopentanol, cyclohexanol, etc. can be used, and 1-butanol is preferred. Alcohol, 2-butanol, 3-methyl-1-butanol, isopropyl alcohol. Examples of the hydrocarbon-based solvent include aromatic hydrocarbon-based solvents such as toluene and xylene, and aliphatic hydrocarbon-based solvents such as octane, decane, and dodecane.

A plurality of the above-mentioned components may be mixed, or they may be mixed with organic solvents other than the above-mentioned ones.

The above-mentioned organic solvent can also be mixed with water, but the water content in the rinse liquid is usually 30 mass% or less, preferably 10 mass% or less, more preferably 5 mass% or less, especially 3 mass% or less. The rinse solution preferably does not contain water. By setting the moisture content to 30% by mass or less, good development characteristics can be obtained.

An appropriate amount of surfactant can also be added to the rinse solution. As the surfactant, the same ones as those described above as the surfactant used in the photosensitive composition can be used. The usage amount of the surfactant is usually 0.001 to 5 mass%, preferably 0.005 to 2 mass%, and further preferably 0.01 to 0.5 mass% relative to the total amount of the rinse liquid.

＜rinsing method＞ In the rinsing step, the developed pattern forming substrate is cleaned using the above rinsing liquid containing an organic solvent.

The method of cleaning treatment is not particularly limited. For example, the following methods 1) to 3) can be applied. 1) A method of continuously applying rinse liquid onto a substrate rotating at a certain speed (spin coating method) 2) Method of immersing the substrate in a tank filled with rinse liquid for a certain period of time (immersion method) 3) Method of spraying the rinse liquid onto the surface of the substrate (spray method) Among them, it is preferable to use a spin coating method to perform the cleaning process, and after cleaning, the substrate is rotated at a rotation speed of 2000 to 4000 rpm to remove the rinse liquid from the substrate. The rotation time of the substrate can be set within the range required to remove the rinse liquid from the substrate according to the rotation speed, usually from 10 seconds to 3 minutes. Rinsing is preferably carried out at room temperature.

The rinse time is preferably such that the development solvent does not remain on the substrate, and is generally preferably 10 to 300 seconds, more preferably 20 to 120 seconds. The temperature of the rinse liquid is preferably 0 to 50°C, and more preferably 15 to 35°C. The amount of flushing liquid can be adjusted appropriately according to the flushing method.

[Post-processing steps] After the development process or the rinsing process, a supercritical fluid may also be used to remove the developer or rinsing liquid attached to the pattern. Furthermore, after the development process, the rinse process, or the treatment using a supercritical fluid, a heat treatment may also be performed to remove the solvent remaining in the pattern. The heating temperature and time are not particularly limited as long as a good photoresist pattern can be obtained, usually 40 to 160°C and 10 seconds to 3 minutes. The heat treatment can also be performed a plurality of times.

[use] The photosensitive composition and pattern forming method of the present invention can be favorably used in the production of semiconductor microcircuits such as the production of super LSI or high-capacity microchips. When making semiconductor microcircuits, a photoresist film with a pattern is used for circuit formation or etching, and the remaining photoresist film portion is eventually removed with a solvent, etc., so it is different from the so-called permanent photoresist used for printed circuit boards, etc. In final products such as microchips, the photoresist film derived from the photosensitive composition of the present invention does not remain. Example

Hereinafter, the present invention will be described in further detail using examples. The content of the present invention is not limited thereto.

[Example 1] ＜Synthesis of Compound 1＞ Under nitrogen atmosphere, phenol (100 g, 1062 mmol), DMSO (83.0 g) and methanol (750 ml) were added to the reaction vessel, and cooled to the internal temperature of 0°C using an ice-salt bath. After hydrogen chloride gas was introduced for 4 days, the mixture was concentrated under reduced pressure, azeotroped with acetone to precipitate crystals, and the crystals were filtered to obtain 58.84 g of intermediate 1-1 represented by the following structural formula.

[Chemical 13]

Secondly, under nitrogen atmosphere, intermediate 1-1, NaCF ₃ SO ₃ (12.65 g, 313.0 mmol) and acetone (410 ml) were added to the reaction vessel, and the reaction was carried out at room temperature overnight. The precipitated salt was removed by filtration and concentrated under reduced pressure to obtain 88.26 g of the intermediate 1-2 represented by the following structural formula.

[Chemical 14]

Under nitrogen atmosphere, intermediate 1-2, NaOH (12.16 g, 304 mol) and methanol (580 ml) were added to the reaction vessel, and stirred at room temperature for one hour. Use an ice-salt bath to cool the internal temperature to 0°C, filter to remove the precipitated salt, and concentrate under reduced pressure to obtain intermediate 1-3 (70.32 g, 215 mmol, yield 20.3%) represented by the following structural formula. .

[Chemical 15]

Under a nitrogen atmosphere, intermediate 1-3 (3.26 g, 10.0 mmol) and acetonitrile (20.0 ml) were added to the reaction vessel, and diisopropylamine formamide chloride (1.96 g, 12.0 mmol) was added dropwise. React at room temperature for 6 hours, filter to remove the precipitate, concentrate the filtrate under reduced pressure, use diisopropyl ether to crystallize and wash, thereby obtaining intermediate 1-4 (3.54 g) represented by the following structural formula , 8.20 mmol, yield 82.0%).

[Chemical 16]

Add purified water (18.5 ml) dissolved in H ₄ [SiW ₁₂ O ₄₀ ] (2.77 g, 0.811 mmol) to the reaction vessel under nitrogen atmosphere, and add CH of intermediate 1-4 (3.50 g, 8.11 mmol) dropwise. A solution of ₂ Cl ₂ (18.5 ml). The reaction was carried out at 20° C. for 0.5 hours, and the precipitate was filtered and dried under reduced pressure to obtain compound 1 (2.69 g) represented by the following structural formula. ¹ H-NMR (400 MHz, DMSO-d ₆ ): δ8.08-8.10 (2H, m, ArH), 7.47-7.50 (2H, m, ArH), 3.26 (6H, s, CH ₃ ), 3.18 ( 2H, m, CH), 1.21 (6H, d, CH ₃ ); ESI (+) -MS: 282.15; ESI (-) -MS: 1437.60 (H ₂ [SiW ₁₂ O ₄₀ ] ^2- ).

[Chemical 17]

＜Preparation of photoresist liquid＞ The compound 1 synthesized as above was dissolved in cyclohexanone at a concentration of 5% by mass, and filtered with a 0.2 μm filter to prepare a photoresist liquid 1.

＜Evaluation of sensitivity＞ The prepared photoresist liquid 1 is used to form a photoresist film and patterned. Specifically, the photoresist liquid 1 is coated on the pattern forming substrate (silicon wafer) by spin coating to form a photoresist film with a film thickness of about 50 nm. The obtained photoresist film was dried at 90° C. for 90 seconds, and then pattern drawing was performed using an electron beam drawing device (the acceleration voltage of the electron beam was 100 keV). After the pattern is drawn, it is developed using cyclohexanone or ethyl lactate to obtain a negative pattern. A contact profilometer is used to measure the film thickness of the pattern obtained by electron beam drawing and development by changing the irradiation amount, and the sensitivity is set to the irradiation amount of the electron beam at which the change in the film thickness is increased to the maximum. The evaluation results are shown in Table 1.

＜Evaluation of resolution＞ Secondly, an electron beam drawing device is used to evaluate the resolution of the photoresist liquid 1. The resolution is evaluated by drawing line and space (line:space=1:1) patterns with hp (half pitch) of 100 nm and hp50 nm, developing them, and observing each pattern with a scanning electron microscope. Advantages and Disadvantages (Excellent/Inferior). The evaluation results are shown in Table 2.

[Comparative example 1] ＜Synthesis of Compound 2＞ Under a nitrogen atmosphere, the intermediate 1-3 (3.19 g, 9.73 mmol) and acetonitrile (20.0 ml) of the above Example 1 were added to the reaction vessel, and methacrylic acid chloride (1.13 ml, 11.68 mmol) was added dropwise. React at room temperature for 6 hours, filter to remove the precipitate, concentrate the filtrate under reduced pressure, use diisopropyl ether to crystallize and wash, thereby obtaining intermediate 2-1 (3.54 g) represented by the following structural formula , 8.20 mmol, yield 82.0%).

[Chemical 18]

Purified water (13.0 ml) dissolved in H ₄ [SiW ₁₂ O ₄₀ ] (1.93 g, 0.56 mmol) was added to the reaction vessel under nitrogen atmosphere, and CH of intermediate 2-1 (2.10 g, 5.64 mmol) was added dropwise. A solution of ₂ Cl ₂ (13.0 ml). React at 20°C for 0.5 hours, filter out the precipitate, and dry under reduced pressure to obtain compound 2 (2.60 g) represented by the following structural formula. ¹ H-NMR (400 MHz, DMSO-d ₆ ): δ8.14-8.16 (2H, m, ArH), 7.58-7.60 (2H, m, ArH), 6.33 (1H, d, CH ₂ ), 5.98 ( 1H, d, CH ₂ ), 3.27 (6H, s, CH ₃ ). 2.02 (3H, s, CH ₃ ); ESI (+) -MS: 223.08; ESI (-) -MS: 1437.60 (H ₂ [SiW ₁₂ O ₄₀ ] ^2- ).

[Chemical 19]

＜Preparation and evaluation of photoresist liquid＞ Except using Compound 2 instead of Compound 1, a photoresist liquid 2 was prepared in the same manner as in Example 1, and a sensitivity test was conducted in the same manner. The results are shown in Table 1.

[Comparative example 2] ＜Synthesis of Compound 3＞ Under a nitrogen atmosphere, the intermediate 1-3 (3.19 g, 9.73 mmol) and acetonitrile (20.0 ml) of the above Example 1 were added to the reaction vessel, and nonyl chloride (2.20 ml, 11.68 mmol) was added dropwise. React at room temperature for 6 hours, filter to remove the precipitate, concentrate the filtrate under reduced pressure, use diisopropyl ether to crystallize and wash, thereby obtaining intermediate 3-1 (3.20 g) represented by the following structural formula , 7.20 mmol, yield 74.0%).

[Chemistry 20]

Purified water (16.4 ml) dissolved in H ₄ [SiW ₁₂ O ₄₀ ] (2.46 g, 0.72 mmol) was added to the reaction vessel under nitrogen atmosphere, and CH of intermediate 3-1 (3.20 g, 7.20 mmol) was added dropwise. A solution of ₂ Cl ₂ (16.4 ml). The reaction was carried out at 20° C. for 0.5 hours, and the precipitate was filtered and dried under reduced pressure to obtain compound 3 (2.76 g) represented by the following structural formula. ¹ H-NMR (400 MHz, DMSO-d ₆ ): δ8.12-8.14 (2H, m, ArH), 7.50-7.52 (2H, m, ArH), 3.26 (6H, s, CH ₃ ), 2.63 ( 2H, t, CH ₂ ), 1.66 (2H, m, CH ₂ ), 1.28 (10H, m, CH ₂ ), 0.88 (3H, t, CH ₃ ); ESI (+) -MS: 295.17; ESI (- ) -MS: 1437.60 (H ₂ [SiW ₁₂ O ₄₀ ] ^2- ).

[Chemistry 21]

＜Preparation and evaluation of photoresist liquid＞ Except using Compound 3 instead of Compound 1, the photoresist liquid 3 was prepared in the same manner as in Example 1, and the sensitivity was evaluated in the same manner. The results are shown in Table 1.

[Comparative example 3] Polyhydroxystyrene (PHS, weight average molecular weight 11000) manufactured by Aldrich was dissolved in propylene glycol monomethyl ether acetate at a concentration of 2% by mass, and filtered with a 0.2 μm filter to prepare a photoresist liquid 4.

[Comparative example 4] Polystyrene (PS, weight average molecular weight 4000) manufactured by Aldrich was dissolved in propylene glycol monomethyl ether acetate at a concentration of 2% by mass, and filtered with a 0.2 μm filter to prepare photoresist liquid 5 . The sensitivity and resolution were evaluated in the same manner as in Example 1 except that photoresist liquids 4 and 5 were used instead of photoresist liquid 1. The results are shown in Tables 1 and 2.

[Table 1] Compounds in photoresist liquid Sensitivity (mC/cm ² ) Example 1 Compound 1 <1 Comparative example 1 Compound 2 >5 Comparative example 2 Compound 3 >5 Comparative example 3 PHS <1 Comparative example 4 P.S. <1

According to the results in Table 1 above, it can be seen that compared with Comparative Examples 1 and 2, Example 1 using the compound of the present invention has higher lithography sensitivity.

[Table 2] Compounds in photoresist liquid resolution HP100 nm hp50nm Example 1 Compound 1 Excellent Excellent Comparative example 3 PHS Excellent inferior Comparative example 4 P.S. Excellent inferior

From the results of the above Table 2, it is understood that when the photosensitive composition of Example 1 using the compound of the present invention is used, resolution can be improved. If we refer to the photosensitive reaction mechanism of photoresist, it can be inferred that the resolution is also higher for EUV light (13.5 nm) photosensitivity.

As mentioned above, the compound and photosensitive composition of the present invention can also form photoresist patterns with reduced roughness in future EUV lithography, which has great industrial value.

The present invention has been described in detail using specific forms, but it will be apparent to those skilled in the art that various changes can be made without departing from the intention and scope of the present invention. This application is based on Japanese Patent Application 2022-047100 filed on March 23, 2022, the entire text of which is incorporated by reference.

Claims (12)

A compound containing a heteropolyacid anion, a photoreactive cation represented by the following formula (1), and a hydrogen cation; [Chemical 1] (In the above formula (1), R ¹ and R ² are each independently an optionally substituted chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or a carbon An aromatic group with a number of 3 to 10; Q is a saturated aliphatic hydrocarbon chain or aromatic chain that may have a substituent; G is a substituent with a monovalent cation). For example, the compound of claim 1 has a molecular weight of 110 to 500. Such as the compound of claim 1 or 2, wherein the above-mentioned heteropolyacid anion is one or two selected from the group consisting of phosphotungstate anion, silicotungstate anion, phosphomolybdate anion, phosphotungstomolybdate anion and phosphovanadium molybdate anion. above. The compound according to any one of claims 1 to 3, wherein R ¹ and R ² in the above formula (1) are each independently the carbon atom adjacent to the nitrogen atom in the above formula (1) is secondary or tertiary. A chain of saturated aliphatic hydrocarbon groups of carbon atoms. The compound according to any one of claims 1 to 4, wherein Q in the above formula (1) is a phenylene group which may have a substituent. The compound of any one of claims 1 to 5, wherein G in the above formula (1) is an ammonium cation, a sulfonium cation or a phosphonium cation. A photosensitive composition comprising a compound according to any one of claims 1 to 6. A photosensitive composition comprising a compound according to any one of claims 1 to 6 and an organic solvent. A photosensitive composition containing the compound according to any one of claims 1 to 6 and a photoacid generator that generates acid by the action of chemical radiation. The photosensitive composition according to any one of claims 7 to 9 is for chemical radiation with a wavelength of 6.5 to 13.5 nm. A pattern forming method, which includes the following steps: using the photosensitive composition according to any one of claims 7 to 10 to form a photosensitive layer on a substrate; irradiating a predetermined area of the photosensitive layer with chemical radiation to perform pattern exposure; and using a developer to develop the exposed photosensitive layer to selectively remove the exposed portion or the unexposed portion of the photosensitive layer. The pattern forming method of claim 11, wherein the developer is an organic solvent with a solubility parameter (SP value) of 7.5 to 11.