TW201447485A - Radiation-sensitive resin composition, resist pattern-forming method, acid generator and compound - Google Patents

Abstract

The present invention provides a radiation-sensitive resin composition that contains a polymer having a structural unit that includes an acid-labile group; and an acid generator, wherein the acid generator includes a compound including a sulfonate anion having SO3-, wherein a hydrogen atom or an electron-donating group bonds to an [alpha] carbon atom with respect to SO3-, and an electron-withdrawing group bonds to a [beta] carbon atom with respect to SO3-; and a radiation-degradable onium cation. The compound preferably has a group represented by the following formula (1-1) or (1-2). In the following formulae (1-1) and (1-2), R1 and R2 each independently represent a hydrogen atom or a monovalent electron-donating group. R3 represent a monovalent electron-withdrawing group. R4 represents a hydrogen atom or a monovalent hydrocarbon group.

Description

Radiation-sensitive resin composition, photoresist pattern formation method, acid generator and compound

The present invention relates to a radiation sensitive resin composition, a photoresist pattern forming method, an acid generator, and a compound.

The radiation-sensitive resin composition used in the microfabrication by lithography is irradiated by a charged particle beam such as an ArF excimer laser light, a KrF excimer laser light or the like, or an electron beam such as an electron beam. The exposed portion generates an acid, and by the chemical reaction of the acid as a catalyst, the exposure portion and the unexposed portion are caused to have a difference in the dissolution rate with respect to the developing liquid, and a resist pattern is formed on the substrate.

In the radiation-sensitive resin composition, it is required to improve the resolution required for the miniaturization of the processing technique and the rectangular shape of the cross-sectional shape of the photoresist pattern. For this requirement, the type of the polymer, the acid generator, and other components used in the composition or the molecular structure are discussed, and the combination thereof is also discussed in detail (refer to Japanese Patent Laid-Open No. Hei 11-125907, Japanese Patent Application No. Hei 8-- Japanese Patent Publication No. 146610 and Japanese Patent Application Publication No. 2000-298347.

Under this background, in the gradual progress of the refinement of the photoresist pattern, not only the above-described resolution and the rectangular shape of the cross-sectional shape are required, but also the line width roughness (LWR) representing the line width variation of the photoresist pattern is required. Excellent performance. However, the above-mentioned previous radiation-sensitive resin composition does not satisfy this requirement.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 11-125907

[Patent Document 2] Japanese Patent Laid-Open No. Hei 8-146610

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2000-298347

The present invention has been made in view of the above circumstances, and an object thereof is to provide a radiation sensitive resin composition excellent in LWR performance.

The invention to solve the above problems is a radiation sensitive resin composition containing a polymer having a structural unit containing an acid dissociable group (hereinafter also referred to as "[A] polymer"), and acid generation. (hereinafter, also referred to as "[B] acid generator"); the acid generator includes a compound having a sulfonate anion and a radiation-decomposable phosphonium cation, and the sulfonate anion is composed of SO ₃ ^- and is present in the SO ₃ ^- bonding position on the α carbon atom of a hydrogen atom or an electron-donating group, the position on the β carbon atom bonded to a group formed by electron withdrawing.

The photoresist pattern forming method of the present invention comprises the steps of: forming a photoresist film, exposing the photoresist film, and developing the exposed photoresist film; and the photoresist film has a radiation linearity A resin composition is formed.

The acid generator of the present invention is a compound comprising a sulfonate anion and a radiation-decomposable phosphonium cation, wherein the sulfonate anion is a group comprising SO ₃ ^- , and a hydrogen atom is bonded to a carbon atom of the α-position of the SO ₃ ^- or An electron-donating group is obtained by bonding one electron-withdrawing group to a carbon atom at the β-position.

The compound of the present invention has a sulfonate anion and a radiation-decomposable phosphonium cation, and the sulfonate anion is a group containing SO ₃ ^- , and a hydrogen atom or an electron-donating group is bonded to the carbon atom of the α-position of the SO ₃ ^- The carbon atom at the β position is bonded to one electron-withdrawing group.

According to the radiation sensitive resin composition and the photoresist pattern of the present invention, a LWR small photoresist pattern can be formed. The acid generator of the present invention can be suitably used as a component of a radiation sensitive resin composition, and can be used. Its LWR performance is improved. The compound of the present invention can be suitably used as the acid generator. Therefore, these can be suitably used in the lithography step of a semiconductor manufacturing process, such as a semiconductor manufacturing process which is expected to be further refined in the future.

<Inductive Radiation Resin Composition>

The radiation sensitive resin composition contains the [A] polymer and the [B] acid generator. The radiation sensitive resin composition may further contain a [C] acid diffusion control body of a suitable component, [D] a fluorine atom-containing polymer (hereinafter also referred to as "[D] polymer"), and [E] solvent. Other optional components may be contained without damaging the scope of the effects of the present invention. Hereinafter, each component will be described.

<[A]polymer>

[A] The polymer is a polymer having a structural unit containing an acid-dissociable group (hereinafter also referred to as "structural unit (I)"). The "acid dissociable group" refers to a group which is substituted with a hydrogen atom such as a carboxyl group or a phenolic hydroxyl group, and which is decomposed by the action of an acid. The [A] polymer in the radiation sensitive resin composition is excellent in pattern formation property by the structural unit (I).

In addition to the structural unit (I), the [A] polymer has at least one structural unit (II) selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure, which will be described later. Preferably, it may have other structural units other than structural units (I) and (II). Hereinafter, each structural unit will be described.

[structural unit (I)]

The structural unit (I) is a structural unit containing an acid dissociable group. The structural unit (I) is not particularly limited as long as it contains an acid-dissociable group, and examples thereof include a structural unit derived from an acid-dissociable ester of an unsaturated carboxylic acid, and an acid-dissociable group derived from hydroxystyrene. The structural unit of the ester, etc., but the structural unit represented by the following formula (4) from the viewpoint of enhancing the pattern formation property of the radiation-sensitive resin composition (hereinafter, also referred to as "structural unit (I-1)" ) is better.

In the above formula (4), R ⁷ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ⁸ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ⁹ and R ¹⁰ each independently represent a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or these groups are bonded to each other and bonded thereto. The carbon atoms together constitute an alicyclic structure having a carbon number of 3-20.

As the above R ⁷ , a hydrogen atom or a methyl group is preferred from the viewpoint of the copolymerization property of the monomer to which the structural unit (I) is added, and a methyl group is preferred.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the above R ⁸ include a chain hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 1 to 20 carbon atoms, and a carbon number of 6 A monovalent aromatic hydrocarbon group of ~20.

Examples of the chain hydrocarbon group having 1 to 10 carbon atoms represented by the above R ⁸ to R ¹⁰ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and a 2-methyl group. An alkyl group such as a 1-methylpropyl group or a t-butyl group; an alkenyl group such as a vinyl group, a propenyl group or a butenyl group; an alkynyl group such as an ethynyl group, a propynyl group or a butynyl group; and the like.

Examples of the alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ⁸ to R ¹⁰ include a monocyclic cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group or a cyclohexyl group; a polycyclic cycloalkyl group such as a cyclyl group, an adamantyl group, a tricyclodecyl group or a tetracyclododecyl group; a cycloalkenyl group such as a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group or a cyclohexenyl group; a polycyclic cycloalkenyl group such as a nonenyl group, a tricyclodecenyl group or a tetracyclododecenyl group.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms represented by the above R ⁸ include an aryl group such as a phenyl group, a tolyl group, a fluorenyl group, a naphthyl group or a fluorenyl group; and a benzyl group and a phenethyl group; An aralkyl group such as naphthylmethyl.

The above R ^{8 is} preferably a chain hydrocarbon group having 1 to 10 carbon atoms or an alicyclic hydrocarbon group having a carbon number of 3 to 20.

The alicyclic structure having a carbon number of 3 to 20 which is a combination of the chain hydrocarbon group and the alicyclic hydrocarbon group represented by the above-mentioned R ⁹ and R ¹⁰ and which is bonded to the carbon atom to be bonded thereto may, for example, be a cyclopropane. a monocyclic naphthenic structure such as a structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a cycloheptane structure, or a cyclooctane structure; a ring of a single ring such as a cyclopentene structure or a cyclohexene structure; Alkene structure; a polycyclic naphthenic structure of a norbornane structure, an adamantane structure, a tricyclodecane structure, a tetracyclododecane structure, or the like; a polycyclic cycloolefin having a norbornene structure, a tricyclic terpene structure, or the like Construction, etc.

Among these, a monocyclic or polycyclic naphthenic structure is preferred.

Among these, an alicyclic ring in which R ⁸ is an alkyl group having 1 to 4 carbon atoms and R ⁹ and R ¹⁰ are bonded to each other and bonded together with such a carbon atom is a polycyclic or monocyclic ring. The alkane structure is preferred.

Examples of the structural unit (I-1) include structural units represented by the following formulas (4-1) to (4-4) (hereinafter, also referred to as "structural units (I-1-1) - ( I-1-4)") and so on.

In the above formulae (4-1) to (4-4), R ⁷ to R ¹⁰ are the same as in the above formula (4). The i and j systems are each independently an integer from 1 to 4.

The i and j are preferably 1.

The structural unit (I-1-1) to (I-1-4) may, for example, be a structural unit represented by the following formula.

In the above formula, R ⁷ is synonymous with the above formula (4).

As the structural unit (I), among these, it is preferable that the structural unit (I-1-1) and the structural unit (I-1-2) are structural units having a cyclopentane structure and have an adamantane structure. Preferably, the structural unit is preferably a structural unit derived from a 1-alkylcyclopentyl (meth) acrylate and a structural unit derived from a 2-alkyladamantyl (meth) acrylate. The structural unit derived from 1-methylcyclohexyl (meth) acrylate and the structural unit derived from 2-ethyladamantyl (meth) acrylate are particularly preferred.

The content ratio of the structural unit (I) is preferably 5 mol% to 95 mol%, and 10 mol% to 90 mol%, based on the total structural unit constituting the [A] polymer. Preferably, 20% to 80% by mole is more preferred, and 30% to 70% by mole is particularly good. By setting the content ratio of the structural unit (I) within the above range, the pattern formation property of the radiation sensitive resin composition can be further improved.

[Structural Unit (II)] The structural unit (II) is a structural unit containing at least one selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure. [A] The polymer has a structural unit (II), and the solubility in the developing solution can be adjusted. As a result, the radiation-sensitive resin composition can improve the lithography performance such as resolution. Moreover, the adhesion between the photoresist pattern formed by the [A] polymer and the substrate can be improved.

The structural unit (II) may, for example, be a structural unit represented by the following formula.

In the above formula, R ^L1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

As the structural unit (II), among these, the structural unit containing the lactone structure is preferred, and the structural unit containing the norbornactone structure is preferred, and is derived from the norbornactone-based group (A). The structural unit of the acrylate is Better.

The content ratio of the structural unit (II) is preferably 20 mol% to 80 mol%, and 25 mol% to 70 mol%, based on the total structural unit constituting the [A] polymer. Preferably, it is more preferably 30 mol% to 60 mol%. By setting the content ratio of the structural unit (II) within the above range, the radiation-sensitive resin composition can improve the lithographic properties such as resolution and the adhesion of the formed photoresist pattern to the substrate. .

[Other construction units]

The [A] polymer may have other structural units in addition to the above structural units (I) and (II). Examples of the other structural unit include a structural unit including a polar group (except for those in the structural unit (II)). [A] The polymer can adjust the solubility in the developing solution by further having a structural unit containing a polar group, and as a result, the lithographic performance such as the resolution of the radiation-sensitive resin composition can be improved. Examples of the polar group include a hydroxyl group, a carboxyl group, a cyano group, a nitro group, and a sulfonylamino group. Among these, a hydroxyl group and a carboxyl group are preferred, and a hydroxyl group is preferred.

The structural unit having such a polar group may, for example, be a structural unit represented by the following formula.

In the above formula, R ^A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

The content ratio of the structural unit having a polar group is preferably 0 mol% to 40 mol%, and 0 mol% to 30 mol% with respect to the total structural unit constituting the [A] polymer. % is preferred, and 0% by mole to 20% by mole is more preferred. By setting the content ratio of the structural unit having a polar group within the above range, the lithographic performance such as the resolution of the radiation sensitive resin composition can be further improved.

The [A] polymer may have a structural unit other than the above structural unit having a polar group as another structural unit. The content ratio of the structural unit is preferably 30 mol% or less, and preferably 20 mol% or less, based on the total structural unit of the [A] polymer.

<[A] Synthesis Method of Polymer>

The [A] polymer can be synthesized, for example, by polymerizing a monomer to be supplied to each structural unit in a suitable solvent using a radical polymerization initiator or the like.

Examples of the radical polymerization initiator include azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), and 2 , 2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutylene An azo-based radical initiator such as an acid ester; a peroxide-based radical initiator such as benzoyl peroxide, t-butyl hydroperoxide or cumene peroxide. Among these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferred, and AIBN is preferred. These radical initiators may be used alone or in combination of two or more.

As the solvent used in the above polymerization, for example, An alkane such as n-pentane, n-hexane, n-heptane, n-octane, n-decane or n-decane; cyclohexane, cycloheptane, cyclooctane, decahydronaphthalene, a naphthenics such as norbornane; aromatic hydrocarbons such as benzene, toluene, hydrazine, ethylbenzene, cumene; chlorobutanes, bromohexanes, dichloroethanes, dibromide Halogenated hydrocarbons such as methyl or chlorobenzene; saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate, methyl propionate, etc.; acetone, methyl ethyl ketone, 4-methyl Ketones such as keto-2-pentanone and 2-heptanone; ethers such as tetrahydrofuran, dimethoxyethane and diethoxyethane; methanol, ethanol, 1-propanol, 2-propene An alcohol such as an alcohol or 4-methyl-2-pentanol or the like. The solvent used in the polymerization may be used singly or in combination of two or more.

The reaction temperature in the above polymerization is usually from 40 ° C to 150 ° C, preferably from 50 ° C to 120 ° C. The reaction time is usually from 1 hour to 48 hours, preferably from 1 hour to 24 hours.

The weight average molecular weight (Mw) in terms of polystyrene obtained by gel permeation chromatography (GPC) of the polymer is not particularly limited, and is preferably 1,000 or more and 50,000 or less, and more preferably 2,000 or more and 30,000 or less. It is more preferably 3,000 or more and 15,000 or less, and more preferably 4,000 or more and 12,000 or less. [A] If the Mw of the polymer is less than the above lower limit At the time, the heat resistance of the obtained photoresist film is lowered. When the Mw of the polymer exceeds the above upper limit, the developability of the photoresist film may be lowered.

The ratio (Mw/Mn) of the Mw of the polymer to the number average molecular weight (Mn) in terms of polystyrene obtained by GPC is usually 1 or more and 5 or less, preferably 1 or more and 3 or less, and more preferably 1 or more. 2 is better below.

The Mw and Mn of the polymer in the present specification are values measured by gel permeation chromatography (GPC) based on the following conditions.

GPC pipe column: G2000HXL 2, G3000HXL 1 and G4000HXL 1 (above, made by Tosoh)

Column temperature: 40 ° C

Precipitation solvent: tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd.)

Flow rate: 1.0 mL / min

Sample concentration: 1.0% by mass

Sample injection amount: 100 μL

Detector: differential refractometer

Reference material: monodisperse polystyrene

The content of the polymer [A] is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 85% by mass or more based on the total solid content of the radiation sensitive resin composition. .

<[B]acid generator>

[B] The acid generator is a compound containing a sulfonate anion (hereinafter also referred to as "sulfonate anion (A)") and a radiation-decomposable phosphonium cation (hereinafter also referred to as "compound (I)"); the sulfonate anion containing SO ₃ ^- and this SO ₃ ^- of the α position of the carbon atom bonded to a hydrogen atom or an electron-donating group, the position on the β carbon atom bonded to a group formed by electron withdrawing. The radiation sensitive resin composition is excellent in LWR performance by containing a [B] acid generator.

[Compound (I)]

The compound (I) is a compound having a sulfonate anion (A) and a radiation-decomposable phosphonium cation. Hereinafter, the order of the sulfonate anion (A) and the radiation-decomposable phosphonium cation will be described.

(sulfonate anion (A))

Sulfonate anion (A) system comprising SO ₃ ^-, and thereto SO ₃ ^- bonded hydrogen atom or an electron-donating group at the α position of the carbon atom at the β position bonded to carbon atoms have an electron withdrawing A sulfonate anion. "SO ₃ ^- of the α position carbon atom" means SO ₃ ^- carbon atoms are bonded, the "SO ₃ ^- position of the β carbon atom" means in the position adjacent to the α carbon atom this carbon atom. The compound (I) of the [B] acid generator in the radiation sensitive resin composition is excellent in LWR performance by having a sulfonate anion (A). The reason why the sulfonate anion (A) has the above structure and the radiation sensitive resin composition is excellent in LWR performance is not sufficiently clear, and for example, in the sulfonate anion (A), in the α position The electron-withdrawing group is not bonded, and only one electron-withdrawing group is bonded to the carbon atom at the β-position, so that the [B] acid-producing product can exhibit a more moderate acidity and the like than the previous acid generator.

The electron-donating group is not particularly limited as long as it is more likely to impart electrons to the bonded atom side than the hydrogen atom, and may be a monovalent group or a divalent or higher group, but may be a monovalent group. The basis is better. Further, the electron-donating group may be bonded to one carbon atom of the α-position or may be bonded to two.

Examples of the electron-donating group include a hydrocarbon group, a hydroxyl group, an oxyhydrocarbon group, an oxycarbonyl hydrocarbon group, an amine group, a hydrocarbon-substituted amine group, and a hydrocarbon-substituted guanamine group. From the viewpoint of more appropriate acidity of the acid which can be produced from the compound (I), a hydrocarbon group, an oxyhydrocarbyl group or an amine group is preferred among these.

Examples of the electron-donating group having a monovalent value include -R', -OH, -OR', -OCOR', -NH ₂ , -NR' ₂ , -NHR', -NHCOR', and the like. R' is a monovalent hydrocarbon group.

Examples of the monovalent hydrocarbon group represented by R' include an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group; an alkenyl group such as a vinyl group, a propenyl group or a butenyl group; and an ethynyl group; a monovalent chain hydrocarbon group such as an alkynyl group such as a propynyl group or a butynyl group; a cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a decyl group or an adamantyl group; a monovalent alicyclic hydrocarbon group such as a cycloalkenyl group such as a cyclobutenyl group, a cyclopentenyl group or a nortenyl group; a phenyl group, a tolyl group, a fluorenyl group, a phenyl group, a naphthyl group or a methylnaphthyl group; An aryl group such as a fluorenyl group or a methyl fluorenyl group; a monovalent aromatic hydrocarbon group such as an aralkyl group such as a benzyl group, a phenethyl group, a phenylpropyl group, a naphthylmethyl group or a decylmethyl group;

As a one-valent electron donating group, the acidity of the acid generated from the compound (I) can be regarded as more moderate, and among these, -R', -OR', -NH ₂ , -NHR' are used. Further, -NR' _{2 is} preferred, and -R' (a monovalent hydrocarbon group) is preferred, and a monovalent chain hydrocarbon group is preferred, an alkyl group is more preferred, and a methyl group is particularly preferred.

As the carbon atom bonded to the above-mentioned α-position, a hydrogen atom is preferred from the viewpoint of easiness of synthesis of the compound (I).

The electron-withdrawing group is not particularly limited as long as it is a hydrogen atom which is more likely to attract electrons from the side of the bonding atom, and may be a monovalent group or a divalent or higher group, but may be a monovalent group. It is better. The above electron-withdrawing group is bonded to one of the carbon atoms of the above-mentioned β-position.

Examples of the electron-withdrawing group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, a halogenated hydrocarbon group, a nitro group, a cyano group, a decyl group, a carbonyl hydrocarbon group, a carbonyloxy group or a sulfonyl group. , carboxyl group, sulfonic acid group, and the like. From the viewpoint of easiness of synthesis of the compound (I), among these, a cyano group, a halogen atom or a halogenated hydrocarbon group is preferred, and the acidity of the acid produced from the compound (I) is more moderate. The cyano group, the fluorine atom or the fluorinated hydrocarbon group is preferred, and the fluorine atom or the fluorinated hydrocarbon group is more preferred, and the fluorinated hydrocarbon is particularly preferred.

Examples of the monovalent electron withdrawing group include a halogen atom, a monovalent halogenated hydrocarbon group, a nitro group, a cyano group, a decyl group, -COR', -CO ₂ R', -SO ₂ R', a carboxyl group, and the like. Sulfonic acid group and the like. R' is a monovalent hydrocarbon group.

The monovalent halogenated hydrocarbon group is, for example, the following, and the monovalent fluorinated hydrocarbon group is exemplified by Fluoromethyl, difluoromethyl, trifluoromethyl, fluoroethyl, difluoroethyl, trifluoroethyl, pentafluoroethyl, trifluoropropyl, hexafluoropropyl, heptafluoropropyl, nonafluoro a fluorinated alkyl group of a butyl group; a fluorinated alkenyl group such as a fluorovinyl group or a trifluorovinyl group; a fluorinated chain hydrocarbon group such as a fluorinated alkynyl group such as a fluoroethynyl group; a fluorocyclopentyl group and a perfluoro group; a fluorinated cycloalkyl group such as a cyclopentyl group, a perfluorocyclohexyl group, a perfluoronorbornyl group or a perfluoroadamantyl group; a fluorinated cycloalkenyl group such as a fluorocyclopentenyl group or a difluoronordecenyl group; a fluorinated aryl group of a fluorinated alicyclic hydrocarbon group, a fluorophenyl group, a difluorophenyl group, a trifluorophenyl group, a pentafluorophenyl group, a fluorotolyl group, a trifluorotolyl group, a fluoronaphthyl group, a fluoroantimonyl group or the like A fluorinated aralkyl group such as a fluorobenzyl group, a difluorobenzyl group or a fluoronaphthylmethyl group, and the like, and a monovalent chlorinated hydrocarbon group may, for example, be trichloromethyl, perchlorocyclohexyl or pentachlorophenyl. Examples of the monovalent brominated hydrocarbon group include a tribromomethyl group, a perbromocyclohexyl group, and a pentabromophenyl group. Examples of the monovalent iodinated hydrocarbon group include triiodomethyl group, periodocyclohexyl group, and Iodophenyl and the like.

The monovalent hydrocarbon group represented by the above R' may, for example, be the same as those exemplified as the monovalent hydrocarbon group represented by the above R'.

The monovalent electron withdrawing group is preferably a cyano group, a fluorine atom or a monovalent fluorinated hydrocarbon group, preferably a fluorine atom or a monovalent fluorinated hydrocarbon group, and a monovalent fluorinated hydrocarbon group. Better, with perfluoroalkyl Preferably, trifluoromethyl is preferred.

The carbon atom at the β position of the SO ₃ ^- sulfonate anion (A) may be bonded to a group other than the electron withdrawing group in addition to the above one electron withdrawing group. Examples of the group other than the electron-withdrawing group include a hydrogen atom and a hydrocarbon group.

(radiation decomposing cations)

The radioactive decomposing cation is a cation which is decomposed by irradiation of radiation. In the exposed portion, protons generated by decomposition of the radiation-decomposable phosphonium cation and sulfonic acid generated from the above-described sulfonate anion (A) are generated. Examples of the radiation include electromagnetic waves such as ultraviolet rays, far ultraviolet rays, extreme ultraviolet rays (EUV), X-rays, and γ-rays, and charged particle beams such as electron beams and α-rays. Among them, far ultraviolet rays, EUV, and electron lines are preferred, and far ultraviolet rays are preferred, and KrF excimer laser light (248 nm) and ArF excimer laser light (193 nm) are more preferable, and ArF excimer laser light is used. Very good.

Examples of the radiation-decomposable phosphonium cation include a radioactive decomposed phosphonium cation including an element such as S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, or Bi. . Among these, a phosphonium cation containing the element S (sulfur) and a phosphonium cation containing the element I (iodine) are preferred, and the cation represented by the following formula (X-1) and the following formula (X-2) are used. The cation represented by the cation represented by the following formula (X-3) is preferred.

In the above formula (X-1), R ^a1 , R ^a2 and R ^a3 each independently represent a substituted or unsubstituted carbon number of 1 to 12, a linear or branched alkyl group, a substituted or unsubstituted carbon number. An aromatic hydrocarbon group of 6 to 12, -OSO ₂ -R ^P or -SO ₂ -R ^Q , or a ring structure in which two or more of these groups are bonded to each other. R ^P and R ^Q are each independently substituted or unsubstituted, linear or branched alkyl having 1 to 12 carbon atoms, substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms or substituted or not. Substituting an aromatic hydrocarbon group having 6 to 12 carbon atoms. The k1, k2, and k3 systems are each independently an integer of 0-5. When R ^a1 to R ^a3 and R ^P and R ^Q are each plural, the plural R ^a1 to R ^a3 and R ^P and R ^Q may be the same or different.

In the above formula (X-2), R ^b1 is a substituted or unsubstituted linear or branched alkyl group having 1 to 8 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms. K4 is an integer from 0 to 7. When R ^b1 is a complex number, the plural R ^b1 may be the same or different, and the plural R ^b1 may also represent a ring structure formed by combining with each other. R ^b2 is a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. K5 is an integer from 0 to 6. When R ^b2 is a complex number, the plural R ^b2 may be the same or different, and the plural R ^b2 may also represent a ring structure formed by combining with each other. q is an integer from 0 to 3.

In the above formula (X-3), R ^c1 and R ^c2 each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, and a substituted or unsubstituted carbon number of 6 to 12 The aromatic hydrocarbon group, -OSO ₂ -R ^R or -SO ₂ -R ^S , or a ring structure in which two or more of these groups are bonded to each other. R ^R and R ^S are each independently substituted or unsubstituted, linear or branched alkyl having 1 to 12 carbon atoms, substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms or substituted or not. Substituting an aromatic hydrocarbon group having 6 to 12 carbon atoms. The k6 and k7 systems are each independently an integer from 0 to 5. When each of R ^c1 , R ^c2 , R ^R and R ^S is plural, the plural R ^c1 , R ^c2 , R ^R and R ^S each may be the same or different.

Examples of the unsubstituted linear alkyl group represented by R ^a1 to R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 include a methyl group, an ethyl group, an n-propyl group and an n- group. Butyl and the like.

Examples of the non-substituted branched alkyl group represented by R ^a1 to R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 include i-propyl, i-butyl and sec-butyl. Base, t-butyl and the like.

Examples of the non-substituted aromatic hydrocarbon group represented by R ^a1 to R ^a3 , R ^c1 and R ^c2 include an aryl group such as a phenyl group, a tolyl group, a fluorenyl group, a mesityl group or a naphthyl group; An aralkyl group such as a benzyl group or a phenethyl group.

Examples of the unsubstituted aromatic hydrocarbon group represented by R ^b1 and R ^b2 include a phenyl group, a tolyl group, and a benzyl group.

Examples of the substituent which may be substituted for the hydrogen atom of the alkyl group and the aromatic hydrocarbon group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, a hydroxyl group, a carboxyl group, a cyano group or a nitro group. An alkoxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, a decyl group, a decyloxy group or the like.

Among these, a halogen atom is preferred, and a fluorine atom is preferred.

The above R ^a1 to R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 are an unsubstituted linear or branched alkyl group, a fluorinated alkyl group, an unsubstituted monovalent aromatic hydrocarbon group, OSO ₂ -R", -SO ₂ -R" is preferred, and a fluorinated alkyl group or an unsubstituted monovalent aromatic hydrocarbon group is preferred, and a fluorinated alkyl group is more preferred. R" is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

In the above formula (X-1), k1, k2 and k3 are preferably an integer of 0 to 2, preferably 0 or 1, more preferably 0.

The k4 in the above formula (X-2) is preferably an integer of 0 to 2, preferably 0 or 1, more preferably 1 or more. K5 is preferably an integer of 0 to 2, preferably 0 or 1, more preferably 0.

K6 and k7 in the above formula (X-3) are preferably an integer of 0 to 2, preferably 0 or 1, more preferably 0.

Examples of the phosphonium cation include cations represented by the following formulas (i-1) to (i-67).

In addition, examples of the phosphonium cation include a cation represented by the following formulas (ii-1) to (ii-39).

As the radiation-decomposable phosphonium cation, among these, the phosphonium cation represented by (i-1) and the phosphonium cation represented by (ii-1) are preferred, and the phosphonium cation represented by (i-1) is preferred. good.

(Compound (I))

The compound (I) is not particularly limited as long as it has a compound having the above sulfonate anion (A) and the above-described radiation-decomposable phosphonium cation, but has a group represented by the following formula (1-1) or (1-2). It is better.

In the above formulae (1-1) and (1-2), R ¹ and R ² each independently represent a hydrogen atom or a monovalent electron-donating group. R ³ is a one-valent electron withdrawing group. R ⁴ is a hydrogen atom or a monovalent hydrocarbon group. R ¹ to R ⁴ may also represent a ring structure in which two or more of these are bonded to each other and to the carbon atoms bonded thereto. M ⁺ is a monovalent radioactive decomposed phosphonium cation.

The monovalent electron-donating group represented by the above R ¹ and R ² may be the same as those exemplified as the above-mentioned monovalent electron-donating group.

R ¹ and R ² are preferably a hydrogen atom or a monovalent hydrocarbon group, preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a methyl group, and particularly preferably a hydrogen atom.

The monovalent electron-withdrawing group represented by the above R ³ may be the same as those exemplified as the above-mentioned monovalent electron-withdrawing group. Among these, a cyano group, a fluorine atom, a monovalent fluorinated hydrocarbon group is preferred, a cyano group, a monovalent fluorinated hydrocarbon group is preferred, and a cyano group or a perfluoroalkyl group is more preferred, and a cyano group is preferred. Trifluoromethyl is particularly preferred.

The monovalent hydrocarbon group represented by the above R ⁴ may, for example, be a monovalent chain hydrocarbon group, a monovalent alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon group.

From the viewpoint of easiness of synthesis of the compound (I), the above R ⁴ is preferably a hydrogen atom or a monovalent chain hydrocarbon group, and a hydrogen atom or an alkyl group is preferred, and a hydrogen atom is more preferred.

The ring structure in which two of R ¹ to R ⁴ are bonded to each other and bonded together with the carbon atoms bonded thereto may, for example, be a cyclobutane structure, a cyclopentane structure or a cyclohexane. An alicyclic structure such as a structure, a decane structure, an adamantane structure, or an aromatic ring structure such as a benzene structure, a toluene structure, a naphthalene structure, or a ruthenium structure.

Among these, a ring structure in which R ¹ and R ^{3 are} bonded to each other is preferable, and an aromatic ring structure is preferable, and a benzene structure is more preferable.

The compound (I) may be in the form of a low molecular compound (hereinafter referred to as "[B] acid generator" as appropriate), may be in the form of a polymer, or may be in the form of both.

The compound (I) represented by the following formula (2) (hereinafter also referred to as "compound (I-1)") or the like is exemplified as the compound (I).

In the above formula (2), Z is a group represented by the above formula (1-1) or (1-2). X is a linking group of (n+1) valence. n is an integer from 1 to 3. When n is 1, X can also be a single bond. R ⁵ is a hydrogen atom or a monovalent organic group. When n is 2 or more, the plural R ⁵ may be the same or different. Z, X, and R ⁵ may also represent a ring structure in which two or more of these are combined with each other.

Examples of the (n+1)-valent linking group represented by the above X include the following, and the divalent linking group (n=1) is a divalent hydrocarbon group, -O-, -CO- , -COO-, -NR-, -CONH-, -S-, -SO ₂ -, -SO ₃ -, a combination of two or more of these, etc., a trivalent linking group (n= 2) A hydrocarbon group such as a trivalent group may be exemplified, and the hydrocarbon group and -O-, -CO-, -COO-, -NR-, -CONH-, -S-, -SO ₂ - or -SO ₃ - may be combined. The base or the like, the tetravalent linking group (n=3) may be a hydrocarbon group such as a tetravalent group, a combination of the hydrocarbon group and -O-, -CO-, -COO-, -NR-, -CONH-, -S- , -SO ₂ - or -SO ₃ - is formed into a base.

The above R is a monovalent hydrocarbon group.

The above n is preferably 1 or 2, and preferably 1 is preferred.

When N is 1, X is preferably a single bond, a divalent hydrocarbon group, -O-, -COO-, -NR-, -CONH-, -S-, -SO ₂ -, -SO ₃ -, and is preferably The key, -COO- is preferred.

The monovalent organic group represented by the above R ⁵ may, for example, be a monovalent hydrocarbon group, a hetero atom-containing group containing a group having a hetero atom between carbon-carbons of the hydrocarbon group, and a substituent substituted with the substituent. A part or all of a hydrogen atom having a hetero atom group or the like.

The monovalent hydrocarbon group may, for example, be a chain hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms.

Examples of the chain hydrocarbon group include an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group, an alkenyl group such as a vinyl group, a propenyl group or a butenyl group, an ethynyl group, a propynyl group or a butyne group. An alkynyl group or the like.

Examples of the alicyclic hydrocarbon group include a monocyclic cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group or a cyclohexyl group; and a thiol group, an adamantyl group or a tricyclodecyl group; a cycloalkyl group of a ring; a monocyclic cycloalkenyl group such as a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group or a cyclohexenyl group; a polycyclic cycloolefin having a norbornyl group, a tricyclodecenyl group or the like; Base.

Examples of the aromatic hydrocarbon group include an aryl group such as a phenyl group, a tolyl group, a fluorenyl group, a naphthyl group or a fluorenyl group; and an aralkyl group such as a benzyl group, a phenethyl group or a naphthylmethyl group.

Examples of the group having a hetero atom include -O-, -CO-, -NH-, -S-, a group in which these are combined, and the like.

Examples of the above substituent include a hydroxyl group and a carboxyl group. a group, an oxyhydrocarbyl group, a carbonyloxyhydrocarbyl group, a fluorenyl group, a decyloxy group, a cyano group, a nitro group, a ketone group (=O) or the like.

The above organic group may also be an acid dissociable group. By using the organic group as an acid dissociable group, the compound (I) generates a carboxyl group in the exposed portion, and as a result, the contrast between the exposed portion and the unexposed portion can be improved, and the radiation-sensitive resin composition can be lifted. LWR performance. The acid dissociable group is, for example, the same as the group exemplified as the acid dissociable group in the above [A] polymer. Among them, a hydrocarbon group having a carbon atom of 3 is used as a bond, and a cycloalkyl group in which a carbon atom at the bond is substituted with an alkyl group is preferred, and 2-alkyl-2-adamantane is preferred. The base is better.

R ⁵ is preferably a monovalent organic group, preferably a hydrocarbon group or a lactone-containing group, and more preferably an alkyl group, a cycloalkyl group or a lactone-containing group, and an ethyl group, a cyclohexyl group, or the like. Adamantyl, 2-methyl-2-adamantyl, 2-oxa-3-oxo-4,7,7-trimethylbicyclo[2.2.1]heptan-1-yl, norbornane The lactone-2-yl group is particularly preferred.

Examples of the ring structure in which two or more of Z, X, and R ⁵ are bonded to each other include, for example, R ¹ to R ⁴ in the above formulae (1-1) and (1-2). The loops that can be constructed are the same or the like.

Examples of the compound (I-1) include compounds represented by the following formulas (2-1) to (2-13) (hereinafter, also referred to as "compounds (2-1) to (2-13)" )Wait.

In the above formulae (2-1) to (2-13), M ⁺ is a monovalent radiation-decomposable phosphonium cation.

Among these, the compounds (2-1) to (2-7) are preferred.

The compound (I) which is the above-mentioned polymer is, for example, a polymer having a structural unit represented by the following formula (3) (hereinafter also referred to as "structural unit (a)"). This structural unit (a) can also be introduced into the above [A] polymer.

In the above formula (3), Z is a group represented by the above formula (1-1) or (1-2). Y is a divalent linking group. R ⁶ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Z and Y may also represent a ring structure formed by combining them with each other.

For example, the group of the valence of the above-mentioned Y is exemplified as a group of the valence of X in the linking group of X in the above formula (2).

Among them, a single bond, a divalent hydrocarbon group, -O-, -COO-, and a combination of these two groups are preferred.

As the above R ⁶ , a hydrogen atom or a methyl group is preferred from the viewpoint of the copolymerization property of the monomer to which the structural unit (a) is added, and a methyl group is preferred.

The ring structure in which Z and Y are combined with each other is, for example, the same as the ring structure which can be constituted by R ¹ to R ⁴ in the above formulae (1-1) and (1-2).

Examples of the structural unit (a) include the following formula (3- 1) The structural unit represented by ~(3-8) (hereinafter, also referred to as "structural unit (3-1) to (3-8))".

In the above formulae (3-1) to (3-8), M ⁺ is a monovalent radiation-decomposable phosphonium cation.

Among these, the structural units (3-1) to (3-4) are preferred.

<Synthesis method of compound (I)>

The above compound (I) is, for example, a compound (I-1) wherein n in the above formula (2) is 1 and X is -COO- (in the R ⁵ -bonded carbonyl group) (hereinafter, also referred to as "compound (2') When it is), it can be synthesized according to the following reaction scheme.

In the above reaction scheme, each of R ¹ and R ² is independently a hydrogen atom or a monovalent electron-donating group. R ³ is a one-valent electron withdrawing group. R ⁴ is a hydrogen atom or a monovalent hydrocarbon group. R ¹ to R ⁴ may also represent a ring structure in which two or more of these are bonded to each other and to the carbon atoms bonded thereto. Z is a halogen atom. M ⁺ is a monovalent radioactive decomposed phosphonium cation. E ^- is an anion of 1 valence. R ⁵ is a monovalent organic group. Q is a halogen atom, -OH or -OCOR ¹¹ . R ¹¹ is a monovalent hydrocarbon group.

Examples of the halogen atom represented by the above Z and Q include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

From the viewpoint of increasing the yield of the synthesis reaction, it is preferred to use a chlorine atom or a bromine atom, and a Z-based bromine atom, and a Q-based chlorine atom. good.

The halogenated alcohol compound represented by the above formula (a) is reacted with sodium sulfate in a solvent such as water, and then the radiation represented by the above formula M ⁺ E ^- is contained in a solvent such as dichloromethane/water. The salt of the decomposable phosphonium cation is reacted to obtain a sulfonic acid salt having a hydroxyl group represented by the above formula (b). In the presence of a base such as triethylamine or N,N'-dimethyl-4-aminopyridine in a solvent such as dichloromethane, the sulfonate is further reacted with the above formula R ⁵ COQ. The compound represented by the above formula (2') can be obtained by reacting the compound shown.

Further, in the above formula (2), the compound (I-1) wherein n is 1 and X is -COO- (in the R ⁵ bond -O-) (hereinafter, also referred to as "compound (2")") The synthesis can be carried out according to the following reaction scheme.

In the above reaction scheme, each of R ¹ and R ² is independently a hydrogen atom or a monovalent electron-donating group. R ³ is a one-valent electron withdrawing group. R ¹ to R ³ may also represent an alicyclic structure in which two or more of these are bonded to each other and to the carbon atoms bonded thereto. M ⁺ is a monovalent radioactive decomposed phosphonium cation. E ^- is an anion of 1 valence. R ⁵ is a monovalent organic group.

The sodium sulfonate represented by the above formula (d) is produced by reacting a compound represented by the above formula (c) with a sodium hydrogen sulfite in a solvent such as methanol/acetonitrile/water. Next, the sodium sulfonate is reacted with a salt containing the radiation-resolvable phosphonium cation represented by the above formula M ⁺ E ^- in a solvent such as dichloromethane to obtain the formula (2)). Compound.

The compound (I) other than the above compound (2') and the compound (2") can also be synthesized by the same method as above.

[Other acid generators]

The [B] acid generator may contain, in addition to the compound (I), an acid generator other than the compound (I), without impairing the effects of the present invention. The form of the other acid generator may be in the form of a low molecular compound (hereinafter referred to as "another acid generator" as appropriate), or may be in the form of a polymer, or may be in the form of both.

The other acid generator is not particularly limited as long as it is a compound (I), and examples thereof include an onium salt compound and an N-sulfonyloxy imide compound.

Examples of the onium salt compound include a phosphonium salt, a tetrahydrothiophene salt, a phosphonium salt, a phosphonium salt, a diazonium salt, and a pyridinium salt.

Examples of the onium salt include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, and triphenylsulfonium perfluoro-n-octanesulfonate. Triphenylsulfonium 2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenylsulfonium 2-bicyclo[2.2.1]heptane-2- 1,1-difluoroethane sulfonate, triphenyl camphorsulfonate, 4-cyclohexylphenyldiphenylphosphonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylphosphonium Nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylphosphonium perfluoro-n-octanesulfonate, 4-cyclohexylphenyldiphenylphosphonium 2-bicyclo[2.2.1] Hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyldiphenylcamphorsulfonate, 4-methanesulfonylphenyldiphenylphosphonium Fluoromethanesulfonate, 4-methanesulfonylphenyldiphenylphosphonium nonabutanesulfonate, 4-methanesulfonylphenyldiphenylphosphonium perfluoro-n-octanesulfonic acid Salt, 4-methanesulfonylphenyldiphenylphosphonium 2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonyl Phenyldiphenyl camphorsulfonate, triphenylsulfonium 1,1,2,2-tetrafluoro-6-(1-adamantanecarbonyloxy)hexane-1-sulfonate An acid salt, triphenylsulfonium 1,1-difluoro-2-(adamantan-1-yl)ethane-1-sulfonate or the like.

Examples of the tetrahydrothiophene sulfonium salt include 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiophene trifluoromethanesulfonate and 1-(4-n-butoxynaphthalene). -1-yl)tetrahydrothiophene nonafluoro-n-butanesulfonate, 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiophene perfluoro-n-octanesulfonate , 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiophene 2-cyclobi[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate , 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiophene camphorsulfonate, 1- (6-n-butoxynaphthalen-2-yl)tetrahydrothiophene trifluoromethanesulfonate, 1-(6-n-butoxynaphthalen-2-yl)tetrahydrothiophene nonafluoro-n- Butane sulfonate, 1-(6-n-butoxynaphthalen-2-yl)tetrahydrothiophene perfluoro-n-octane sulfonate, 1-(6-n-butoxynaphthalene-2 -yl)tetrahydrothiophene 2-cyclobi[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1-(6-n-butoxynaphthalene-2 -yl)tetrahydrothiophene camphorsulfonate, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene trifluoromethanesulfonate, 1-(3,5-dimethyl 4-hydroxyphenyl)tetrahydrothiophene nonabutane sulfonate, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene perfluoro-n-octane Sulfonate, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene 2-cyclobi[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethyl An alkane sulfonate, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene camphorsulfonate, and the like.

Examples of the onium salt include diphenylsulfonium trifluoromethanesulfonate, diphenylsulfonium nonafluoro-n-butanesulfonate, diphenylsulfonium perfluoro-n-octanesulfonate, and Phenylindole 2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, diphenyl camphorsulfonate, bis(4-t-butyl) Phenyl)phosphonium trifluoromethanesulfonate, bis(4-t-butylphenyl)phosphonium nonabutanesulfonate, bis(4-t-butylphenyl)phosphonium perfluoro-n -octane sulfonate, bis(4-t-butylphenyl)indole 2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethane sulfonate, double (4-t-butylphenyl) camphorsulfonate and the like.

Examples of the N-sulfodeoxyquinone imine compound include N-(trifluoromethanesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dimethylimine, N. -(nonafluoro-n-butanesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dimethylimine, N-(perfluoro-n-octanesulfonyloxy) Bicyclo[2.2.1]hept-5-ene-2,3-dimethylimine, N-(2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoro Ethylsulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dimethylimine, N-(2-(3-tetracyclo[4.4.0.1 ^2,5 .1 ^{7, 10} ] Twelve-mercapto-1,1-difluoroethanesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dimethylimine, N-(camphorsulfonate) Bicyclo[2.2.1]hept-5-ene-2,3-dimethylimine and the like.

When the [B] acid generator is a [B] acid generator, the content of the [B] acid generator is preferably 0.1 parts by mass to 30 parts by mass based on 100 parts by mass of the [A] polymer. It is preferably 0.5 parts by mass to 20 parts by mass, more preferably 1 part by mass to 15 parts by mass. The content of the [B] acid generator is set within the above range, and the radiation sensitive resin composition can improve the sensitivity, and as a result, the LWR performance can be improved.

When the [B] acid generator is a [B] acid generator, the content of the compound (I) in the [B] acid generator is preferably 20% by mass to 100% by mass, and 25% by mass to 90% by mass. The mass % is preferably from 30% by mass to 70% by mass. When the content of the compound (I) is set within the above range, the radiation-sensitive resin composition can further improve the LWR performance.

The content of the compound (I) in the radiation sensitive resin composition is 0.1 mass per 100 parts by mass of the [A] polymer when the [B] acid generator is the [B] acid generator. The parts to 30 parts by mass are preferably based on 1 part by mass to 15 parts by mass, more preferably 2 parts by mass to 10 parts by mass. By containing the compound (I) in the above range, the radiation sensitive resin composition can further improve the LWR performance.

<[C] Acid Diffusion Control Body>

The radiation sensitive linear resin composition may also contain [C] acid expansion as necessary Dispersion control body.

[C] Acid Diffusion Control System Controls the diffusion of acid generated from [B] acid generators in the photoresist film by exposure, achieving the effect of suppressing poor chemical reactions in the non-exposure field, and obtaining the sensed radiation The storage stability of the resin composition is further improved, and the resolution of the photoresist is further improved, and the line width variation of the photoresist pattern caused by the change of the standing time from exposure to development processing can be suppressed, thereby obtaining A radiation-sensitive linear resin composition excellent in process stability. The form of the [C] acid diffusion control agent in the radiation sensitive resin composition may be in the form of a low molecular compound (hereinafter referred to as "[C] acid diffusion controlling agent" as appropriate) or may be introduced. The form of a part of the polymer may also be in the form of both.

The compound represented by the following formula (5a) (hereinafter also referred to as "nitrogen-containing compound (I)") as the [C] acid-diffusion controlling agent has two nitrogen atoms in the same molecule. a compound (hereinafter also referred to as "nitrogen-containing compound (II)"), a compound having three nitrogen atoms (hereinafter also referred to as "nitrogen-containing compound (III)"), a guanamine-containing compound, a urea compound, and A nitrogen heterocyclic compound or the like.

In the above formula (5a), R ¹² , R ¹³ and R ¹⁴ each independently represent a hydrogen atom, a linear or branched alkyl group which may be substituted, a cycloalkyl group, an aryl group or an aralkyl group.

Examples of the nitrogen-containing compound (I) include monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; and trialkylamines such as triethylamine. An aromatic amine such as aniline.

The nitrogen-containing compound (II) may, for example, be ethylenediamine, N, N, N', N'-tetramethylethylenediamine or the like.

Examples of the nitrogen-containing compound (III) include polyamine compounds such as polyethyleneimine and polyallylamine; and polymers such as dimethylaminoethyl acrylamide.

Examples of the guanamine-containing compound include formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N. - dimethylacetamide, acetamide, benzalkonium, pyrrolidone, N-methylpyrrolidone, and the like.

Examples of the urea compound include urea, methyl urea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, and 1,3- Diphenylurea, tributylthiourea, and the like.

Examples of the nitrogen-containing heterocyclic compound include pyridines such as pyridine and 2-methylpyridine; and morpholines such as N-propylmorpholine and N-(undecylcarbonyloxyethyl)morpholine. An imidazole such as 2-phenylbenzimidazole; pyrazine, pyrazole, and the like.

Further, as the nitrogen-containing organic compound, a compound having an acid-dissociable group can also be used. Examples of the nitrogen-containing organic compound having an acid dissociable group include Nt-butoxycarbonylpiperidine, Nt-butoxycarbonylimidazole, Nt-butoxycarbonylbenzimidazole, and Nt-butoxygen. Carbocarbonyl- 2-phenylbenzimidazole, N-(t-butoxycarbonyl)di-n-octylamine, N-(t-butoxycarbonyl)diethanolamine, N-(t-butoxycarbonyl)di Cyclohexylamine, N-(t-butoxycarbonyl)diphenylamine, Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-pentyloxycarbonyl-4-hydroxypiperidine, and the like.

Further, as the [C] acid diffusion controlling agent, a photocracking base which is light-sensitive by exposure and which generates a weak acid can also be used. Examples of the photocracking base include an onium salt compound which decomposes and loses acid diffusion controllability by exposure. Examples of the onium salt compound include an onium salt compound represented by the following formula (5b-1), an onium salt compound represented by the following formula (5b-2), and the like.

In the above formula (5b-1) and formula (5b-2), R ¹⁵ to R ¹⁹ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a hydroxyl group or a halogen atom. E ^- and Q ^- are each independently based OH ^- or an anion of the following formula (5b-3) represented by the ^{-, R β -COO -, R} β -SO 3. However, R ^β is an alkyl group, an aryl group or an aralkyl group.

[Chem. 26]

In the above formula (5b-3), R ²⁰ is a linear or branched alkyl group having 1 to 12 carbon atoms or a carbon number of 1 to 12 which is partially or wholly replaced by a fluorine atom. Chain or branched alkoxy group. u is an integer from 0 to 2.

The photocracking base is, for example, a compound represented by the following formula.

As the photo-cracking base, among them, a phosphonium salt is preferred, a triarylsulfonium salt is preferred, and a triphenylsulfate, triphenylsulfonium 10-camphorsulfonate is preferred. .

When the [C] acid diffusion controlling agent is a [C] acid diffusion controlling agent, the content of the [C] acid diffusion controlling agent is 0 mass to 20 mass with respect to 100 parts by mass of the [A] polymer. The portion is preferably from 0.1 part by mass to 15 parts by mass, more preferably from 0.3 part by mass to 10 parts by mass. When the content of the [C] acid diffusion controlling agent exceeds the above upper limit, the sensitivity of the radiation sensitive resin composition may be lowered.

<[D]polymer>

[D] The polymer is a fluorine atom-containing polymer (except for those except [A] polymer). The radiation sensitive linear resin composition contains a [D] polymer, and when the photoresist film is formed, the distribution of the fluoropolymer in the film may be unevenly distributed near the surface of the photoresist film due to the oil repellency characteristic of the fluoropolymer in the film. Since it tends to precipitate, it can suppress precipitation of an acid generator, an acid-diffusion control agent, etc. to a liquid immersion medium at the time of liquid immersion exposure. Moreover, by the water repellency characteristic of the [D] polymer, the contact angle of the photoresist film and the liquid immersion medium can be controlled within a desired range, and the generation of bubble defects can be suppressed. Further, the photoresist film and the liquid immersion medium have a high back contact angle, and the scanning exposure can be performed at a high speed without leaving water droplets. Therefore, the radiation sensitive resin composition can form a photoresist film suitable for the liquid immersion exposure method by containing the [D] polymer.

The polymer [D] is not particularly limited as long as it is a polymer having a fluorine atom, and the fluorine atom content (% by mass) is preferably higher than the [A] polymer in the radiation sensitive resin composition. By the fluorine atom content higher than that of the [A] polymer, the degree of uneven distribution is higher, and the characteristics of water repellency and precipitation inhibition of the obtained photoresist film can be improved.

[D] The fluorine atom content of the polymer is preferably 1% by mass or more, preferably 2% by mass to 60% by mass, more preferably 4% by mass to 40% by mass, and most preferably 7% by mass to 30% by mass. % is especially good. When the fluorine atom content of the polymer [D] is less than the above lower limit, the hydrophobicity of the surface of the photoresist film may be lowered. Further, the fluorine atom content (% by mass) of the polymer can be determined by ¹³ C-NMR spectrum measurement, and the structure can be calculated from the structure.

The [D] polymer is preferably at least one selected from the group consisting of the following structural units (Da) and structural units (Db). The [D] polymer may have one or two or more kinds of structural units (Da) and structural units (Db), respectively.

[structural unit (Da)]

The structural unit (Da) is a structural unit represented by the following formula (6a). The [D] polymer can adjust the fluorine atom content by having a structural unit (Da).

In the above formula (6a), R ^D is a hydrogen atom, a methyl group or a trifluoromethyl group. G is a single bond, an oxygen atom, a sulfur atom, -CO-O-, -SO ₂ -O-NH-, -CO-NH- or -O-CO-NH-. R ^E is a monovalent chain hydrocarbon group having 1 to 6 carbon atoms and having at least one fluorine atom, or an aliphatic cyclic hydrocarbon group having 1 to 20 carbon atoms having at least one fluorine atom.

The chain hydrocarbon group having 1 to 6 carbon atoms having at least one fluorine atom represented by the above R ^E may, for example, be a trifluoromethyl group, a 2,2,2-trifluoroethyl group or a perfluoro group. Ethyl, 2,2,3,3,3-pentafluoropropyl, 1,1,1,3,3,3-hexafluoropropyl, perfluoron-propyl, perfluoro-i-propyl, all Fluorine n-butyl, perfluoro i-butyl, perfluorot-butyl, 2,2,3,3,4,4,5,5-octafluoropentyl, perfluorohexyl, and the like.

The aliphatic cyclic hydrocarbon group having a carbon number of 4 to 20 and having at least one fluorine atom represented by the above R ^E may, for example, be a monofluorocyclopentyl group, a difluorocyclopentyl group or a perfluorocyclopentane group. , monofluorocyclohexyl, difluorocyclopentyl, perfluorocyclohexylmethyl, fluoronorbornyl, fluoroadamantyl, fluoroindolyl, fluoroisoindolyl, fluorotricyclodecyl, fluorotetracycline癸基等.

Examples of the monomer to which the structural unit (Da) is added include trifluoromethyl (meth) acrylate, 2, 2, 2-trifluoroethyl (meth) acrylate, and 2, 2, 2. -trifluoroethyloxycarbonylmethyl (meth) acrylate, perfluoroethyl (meth) acrylate, perfluoro n-propyl (meth) acrylate, perfluoro i-propyl (methyl) Acrylate, perfluoron-butyl (meth) acrylate, perfluoro i-butyl (meth) acrylate, perfluoro t-butyl (meth) acrylate, 2-(1,1,1 ,3,3,3-hexafluoropropyl)(meth)acrylate, 1-(2,2,3,3,4,4,5,5-octafluoropentyl)(meth)acrylate, Perfluorocyclohexylmethyl (meth) acrylate, 1-(2,2,3,3,3-pentafluoropropyl)(meth)acrylate, monofluorocyclopentyl (meth) acrylate, Difluorocyclopentyl (meth) acrylate, perfluorocyclopentyl (meth) acrylate, monofluorocyclohexyl (meth) acrylate, difluorocyclopentyl (meth) acrylate, perfluorocyclo Hexylmethyl Acrylate, fluoronorbornyl (meth) acrylate, fluoroadamantyl (meth) acrylate, fluorodecyl (meth) acrylate, fluoroisodecyl (meth) acrylate, fluorine tri Cyclodecyl (meth) acrylate, fluorotetracyclononyl (meth) acrylate, and the like.

Among these, 2,2,2-trifluoroethyloxycarbonylmethyl (meth) acrylate is preferred.

The content ratio of the structural unit (Da) is preferably 5 mol% to 95 mol%, and 10 mol% to 90 mol%, based on the total structural unit constituting the [D] polymer. Preferably, it is more preferably from 25 mol% to 80 mol%. By making such a ratio, a higher dynamic contact angle can be found on the surface of the photoresist film during immersion exposure.

[structural unit (Db)]

The structural unit (Db) is a structural unit represented by the following formula (6b). [D] The polymer has a hydrophobicity by having a structural unit (Db), so that the dynamic contact angle of the surface of the photoresist film formed by the radiation-sensitive resin composition can be further improved.

In the above formula (6b), R ^F is a hydrogen atom, a methyl group or a trifluoromethyl group. R ²¹ is a hydrocarbon group having a carbon number of 1 to 20 (s+1), and is also bonded to an end of the R ²² side of R ^{21 with an} oxygen atom, a sulfur atom, -NR'-, a carbonyl group, -CO-O- Or the constructor of -CO-NH-. R' is a hydrogen atom or a monovalent organic group. R ²² is a single bond, a chain hydrocarbon group having a carbon number of 1 to 10 or a divalent aliphatic hydrocarbon group having a carbon number of 4 to 20. X ² is a divalent chain hydrocarbon group having 1 to 20 carbon atoms and having at least one fluorine atom. A ¹ is an oxygen atom, -NR"-, -CO-O-* or -SO ₂ -O-*. R" is a hydrogen atom or a monovalent organic group. * indicates that the system is bonded to the binding site of R ²¹ . R ²³ is a hydrogen atom or a monovalent organic group. s is an integer from 1 to 3. However, when s is 2 or 3, the plural R ²² , X ² , A ¹ and R ²³ systems may be the same or different.

When R ²³ is a hydrogen atom, it is preferred because the solubility of the [D] polymer to the alkali developing solution can be improved.

The monovalent organic group represented by the above R ²³ may, for example, be a hydrocarbon group having an acid dissociable group, an alkali dissociable group or a substituent having 1 to 30 carbon atoms.

Examples of the structural unit (Db) include a structural unit represented by the following formulas (6b-1) to (6b-3).

In the above formulae (6b-1) to (6b-3), R ^21' is a linear, branched or cyclic saturated or unsaturated hydrocarbon group having a carbon number of 1 to 20 valence. R ^F , X ² , R ²³ and s are synonymous with the above formula (6b). When s is 2 or 3, the plural X ² and R ²³ systems may be the same or different.

The content ratio of the structural unit (6b) is preferably 0 mol% to 90 mol%, and 5 mol% to 85 mol%, based on the total structural unit constituting the [D] polymer. Preferably, it is preferably from 10 mol% to 80 mol%. By making such a ratio, the degree of reduction in the dynamic contact angle of the surface of the photoresist film formed by the radiation-sensitive resin composition in alkali development can be improved.

[structural unit (Dc)]

The [D] polymer may have a structural unit containing an acid dissociable group (hereinafter also referred to as "structural unit (Dc)") in addition to the above structural units (Da) and (Db) (however, the structure is Except for units (Db)). The shape of the [D] polymer obtained by having a structural unit (Dc) becomes more favorable. The structural unit (Dc) may, for example, be a structural unit (II) or the like in the above [A] polymer.

The content ratio of the structural unit (Dc) is preferably 5 mol% to 90 mol%, and 10 mol% to 80 mol%, based on the total structural unit constituting the [D] polymer. Preferably, it is more preferably from 15 mol% to 75 mol%. If the content ratio of the structural unit (Dc) is less than the above lower limit, the occurrence of development defects in the photoresist pattern may not be sufficiently suppressed. If the content ratio of the structural unit (Dc) exceeds the above upper limit, The hydrophobicity of the surface of the photoresist film is reduced.

[Other construction units]

Further, the [D] polymer may contain, for example, a structural unit containing an alkali-soluble group, and at least one selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure, in addition to the above structural unit. The structural unit of the structure, other structural units including the structural unit of the alicyclic group. Examples of the alkali-soluble group include a carboxyl group, a sulfonylamino group, and a sulfonic acid group. The structural unit having at least one structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure may be a structural unit (III) or the like in the above [A] polymer.

The content ratio of the other structural unit is usually 30 mol% or less, and preferably 20 mol% or less, based on the total structural unit constituting the [D] polymer. When the content ratio of the other structural unit exceeds the above upper limit, the pattern formation property of the radiation sensitive resin composition may be lowered.

The content of the [D] polymer in the radiation sensitive resin composition is preferably 0 to 20 parts by mass, and 0.5 parts by mass to 15 parts by mass based on 100 parts by mass of the [A] polymer. More preferably, it is more preferably 1 part by mass to 10 parts by mass. When the content of the polymer [D] exceeds the above upper limit, the pattern formation property of the radiation-sensitive resin composition may be lowered.

<[E]solvent>

The radiation sensitive resin composition usually contains an [E] solvent. The solvent (E) is not particularly limited as long as it can dissolve or disperse at least the [A] polymer, the [B] acid generator, and the [C] acid diffusion control body contained as desired.

Examples of the [E] solvent include an alcohol solvent, an ether solvent, a ketone solvent, a guanamine solvent, an ester solvent, and a hydrocarbon solvent.

Examples of the alcohol-based solvent include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, and iso. -pentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethyl Butanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, sec-octanol, n-nonanol, 2,6-dimethyl-4-heptanol, n- Sterol, sec-undecyl alcohol, trimethyldecyl alcohol, sec-tetradecyl alcohol, sec-heptadecanol, mercapto alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3 a monoalcoholic solvent such as 5-trimethylcyclohexanol, benzyl alcohol or diacetone alcohol; ethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, A polyvalent alcohol solvent such as triethylene glycol or tripropylene glycol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol Monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethyl Glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol single Ethyl ether, A polyvalent alcohol partial ether solvent such as propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether or dipropylene glycol monopropyl ether.

Examples of the ether solvent include a dialkyl ether solvent such as diethyl ether, dipropyl ether or dibutyl ether; a cyclic ether solvent such as tetrahydrofuran or tetrahydropyran; and diphenyl group; An ether-based solvent containing an aromatic ring such as an ether or anisole (methylphenyl ether).

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, and 2-glycol. a chain ketone solvent such as a ketone (methyl-n-amyl ketone), ethyl-n-butyl ketone, methyl-n-hexyl ketone, di-iso-butyl ketone or trimethyl fluorenone; a cyclic ketone solvent such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone or methylcyclohexanone; 2,4-pentanedione, acetonylacetone, acetophenone or the like.

Examples of the guanamine-based solvent include a cyclic amide-based solvent such as N,N'-dimethylimidazolidinone or N-methylpyrrolidone; N-methylformamide, N,N. - dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropionamide, etc. A chain amide-based solvent or the like.

Examples of the ester solvent include methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, and acetic acid. - pent Ester, i-amyl acetate, sec-amyl acetate, 3-methoxybutyl acetate, methyl amyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, acetic acid An acetate solvent such as cyclohexyl ester, methylcyclohexyl acetate or n-decyl acetate; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol Monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether Polyvalent alcohol partial ether acetate of acid ester, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate a solvent; a lactone solvent such as γ-butyrolactone or valerolactone; a carbonate solvent such as diethyl carbonate, ethyl carbonate, and propyl carbonate; diethylene glycol diacetate, methoxyacetate Triethylene glycol ester, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl acetate, ethyl acetate, lactic acid Methyl ester, ethyl lactate, milk n- butyl, n- amyl lactate, diethyl malonate, dimethyl phthalate, diethyl phthalate and the like.

Examples of the hydrocarbon-based solvent include n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, and 2,2,4-trimethylpentane. An aliphatic hydrocarbon solvent such as n-octane, iso-octane, cyclohexane or methylcyclohexane; benzene, toluene, hydrazine, mesitylene, ethylbenzene, trimethylbenzene, methyl ethyl Base benzene, n-propyl benzene, iso-propyl benzene, diethyl benzene, iso-butyl benzene, An aromatic hydrocarbon solvent such as triethylbenzene, di-iso-propylbenzene or n-pentylnaphthalene.

Among these, an ester solvent or a ketone solvent is preferred, and a polyvalent alcohol partial ether acetate solvent, a cyclic ketone solvent, or a lactone solvent is preferred, and propylene glycol monomethyl ether acetate is preferred. Ester, cyclohexanone, γ-butyrolactone is more preferred. The radiation sensitive resin composition may contain one or more kinds of [E] solvents.

<Other optional ingredients>

The radiation sensitive resin composition may contain other optional components in addition to the above [A] to [E]. Examples of the other optional component include a surfactant, a compound containing an alicyclic skeleton, a sensitizer, and the like. These other optional components may be used alone or in combination of two or more.

(surfactant)

The surfactant can achieve effects such as improved coatability, streaking, and developing properties. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octyl phenyl ether, and polyoxyethylene n-fluorenyl group. A nonionic surfactant such as phenyl ether, polyethylene glycol dilaurate or polyethylene glycol distearate; and commercially available products such as KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.) and Polyflow No. 75. Same as No. 95 (above, Kyoritsu Chemical Co., Ltd.), Eftop EF301, EF303, EF352 (above, manufactured by Tohkem Products), Megafac F171, and F173 (above, DIC system), Fluorad FC430, FC431 (above, Sumitomo 3M system), Asahiguide AG710, Surflon S-382, same SC-101, same SC-102, same SC-103, same SC-104, same SC-105, the same as SC-106 (above, Asahi Glass Industrial Co., Ltd.). The content of the surfactant in the radiation-sensitive resin composition is usually 2 parts by mass or less based on 100 parts by mass of the [A] polymer.

(compound containing alicyclic skeleton)

The compound containing an alicyclic skeleton can achieve effects of improving dry etching resistance, pattern shape, adhesion to a substrate, and the like.

Examples of the alicyclic skeleton-containing compound include adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and 1-adamantanecarboxylic acid t-butyl ester; and deoxycholate t-butyl Ester, t-butoxycarbonyl methyl deoxycholate, deoxycholate of 2-ethoxyethyl deoxycholate; t-butyl lithic acid, t-butoxycarbonyl methyl lithate , cholinate such as 2-ethoxyethyl lithate; 3-[2-hydroxy-2,2-bis(trifluoromethyl)ethyl]tetracycline [4.4.0.1 ^2,5 . ^1,7,10 ]dodecane, 2-hydroxy-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo[4.2.1.0 ^3,7 ]decane, and the like. The content of the alicyclic skeleton-containing compound in the radiation-sensitive resin composition is usually 5 parts by mass or less based on 100 parts by mass of the [A] polymer.

(sensitizer)

The sensitizer exhibits an effect of increasing the amount of acid generated from the [B] acid generator or the like, and can achieve an effect of improving the "apparent sensitivity" of the radiation-sensitive resin composition.

Examples of the sensitizer include, for example, carbazoles, acetophenones, benzophenones, naphthalenes, phenols, hydrazine, ruthenium, bengal rose, anthraquinones, anthraquinones, phenothiazines. Ethyls and the like. These sensitizers may be used singly or in combination of two or more. The content of the sensitizer in the radiation-sensitive resin composition is usually 2 parts by mass or less based on 100 parts by mass of the [A] polymer.

<Modulation method of radiation sensitive resin composition>

The radiation sensitive resin composition can be mixed by, for example, [A] polymer, [B] acid generator, necessary [C] acid diffusion control agent, [D] polymer, etc., and [ E] solvent to prepare. The radiation-sensitive resin composition is preferably filtered by, for example, a filter having a pore diameter of about 0.05 μm after mixing. The solid content concentration of the radiation sensitive resin composition is usually 0.1% by mass to 50% by mass, preferably 0.5% by mass to 30% by mass, and preferably 1% by mass to 20% by mass.

<Photoresist pattern formation method>

The photoresist pattern forming method includes a step of forming a photoresist film by the radiation-sensitive resin composition (hereinafter also referred to as "resist film formation step"), and a step of exposing the photoresist film (hereinafter also referred to as Exposure step And a step of developing the exposed photoresist film (hereinafter also referred to as "development step").

According to the photoresist pattern forming method, since the above-described radiation-sensitive resin composition is used, a photoresist pattern having a small LWR can be formed. Hereinafter, each step will be described.

[Photoresist film forming step]

In this step, a photoresist film is formed using the radiation-sensitive resin composition. Examples of the substrate on which the photoresist film is formed include a tantalum wafer, a conventional wafer such as a wafer coated with ruthenium dioxide or aluminum, and the like. Further, for example, an organic or inorganic antireflection film disclosed in Japanese Patent Publication No. Hei 6-12452 or Japanese Patent Application Laid-Open No. Hei 59-93448 can be formed on a substrate. Examples of the coating method include spin coating, cast coating, roll coating, and the like. After the coating, pre-baking (PB) may be performed in order to volatilize the solvent in the coating film. The PB temperature is usually from 60 ° C to 140 ° C, preferably from 80 ° C to 120 ° C. The PB time is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds. The film thickness of the formed photoresist film is preferably 10 nm to 1,000 nm, and more preferably 10 nm to 500 nm.

In the case of performing the immersion exposure, the radiation-sensitive resin composition does not contain the water-repellent polymer additive such as the above [D] polymer, etc., in order to avoid direct contact between the liquid immersion liquid and the photoresist film. A protective film for liquid immersion which is insoluble to the liquid immersion liquid may be provided on the formed photoresist film. As a protective film for liquid immersion, it can be used for dissolution before the development step. A solvent-peelable protective film which is peeled off by a solvent (for example, see JP-A-2006-227632), and a developing liquid peeling type protective film which is peeled off simultaneously with the development of the developing step (for example, refer to WO2005-069076, WO2006- Any of 035790). However, from the viewpoint of the amount of production, it is preferred to use a protective film for liquid immersion liquid immersion.

[Exposure step]

In this step, the photoresist film formed by the photoresist film forming step is exposed to light by irradiating radiation through a photomask (in accordance with a case, a liquid immersion medium such as water). The radiation used for the exposure is a line width corresponding to the pattern of the object, and examples thereof include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, X-ray, and γ-ray, and charged particle beams such as an electron beam and an alpha line. Among them, far ultraviolet rays and electron beams are preferred, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), and electron beam are preferred, and ArF excimer laser light and electron beam are used. Better.

In the case of exposure by immersion exposure, examples of the liquid immersion liquid to be used include water, a fluorine-based inert liquid, and the like. The liquid immersion liquid is preferably a liquid which is transparent to the exposure wavelength and which can reduce the skew of the optical image projected on the film to a minimum refractive index as small as possible, especially in the case where the exposure light source is an ArF excimer. When the light is emitted (wavelength: 193 nm), it is preferable to use water from the viewpoint of the ease of the operation and the ease of handling. In the case of using water, it is also possible to add an additive which reduces the surface tension of water while increasing the interfacial activity. This additive does not dissolve the photoresist film on the wafer, and can ignore the lens The influence of the optical coating below is preferred. The water used is preferably distilled water.

After the above exposure, post-exposure bake (PEB) is performed to promote the [A] polymer caused by the acid generated from the [B] acid generator in the exposed portion of the photoresist film. It is better to dissociate the acid dissociation group. With this PEB, the difference in solubility with respect to the developing liquid is generated in the exposed portion and the unexposed portion. The PEB temperature is usually 50 ° C ~ 180 ° C, based on 80 ° C ~ 130 ° C. The PEB time is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds.

[development step]

In this step, the exposed photoresist film in the above exposure step is developed. Thereby, a predetermined photoresist pattern can be formed. After the development, it is generally washed with a rinse liquid such as water or alcohol and dried.

As the developing solution used for the above-mentioned development, in the case of alkali development, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium citrate, sodium metasilicate, aqueous ammonia, ethylamine, or the like can be mentioned. N-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH) , pyrrole, piperidine, choline, 1,8-dioxinbicyclo-[5.4.0]-7-undecene, 1,5-dioxabicyclo-[4.3.0]-5-decene At least one of the compounds is dissolved in an aqueous alkali solution or the like. Among them, an aqueous TMAH solution is preferred, and a 2.38 mass% TMAH aqueous solution is preferred.

Further, in the case of organic solvent development, for example, a hydrocarbon solvent or an ether An organic solvent such as a solvent, an ester solvent, a ketone solvent, or an alcohol solvent, or a solvent containing an organic solvent. The above-mentioned organic solvent is, for example, one or two or more kinds of solvents exemplified as the solvent of the [E] in the radiation-sensitive resin composition. Among these, an ester solvent or a ketone solvent is preferred. The ester solvent is preferably an acetate solvent, and n-butyl acetate is preferred. The ketone solvent is preferably a chain ketone, and 2-heptanone is preferred. The content of the organic solvent in the developing solution is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and particularly preferably 99% by mass or more. Examples of the component other than the organic solvent in the developing solution include water and eucalyptus oil.

As a developing method, for example, a method of immersing a substrate in a tank filled with a developing liquid for a certain period of time (dipping method), and a developing solution is piled up on the surface of the substrate by surface tension and allowed to stand for a certain period of time. A method of developing a puddle method (a puddle method), a method of spraying a developing solution on a surface of a substrate (spraying method), and a scanning liquid at a constant speed on a substrate rotating at a constant speed A method in which a nozzle discharges a developing liquid at the same time (dynamic dispensing method).

<acid generator>

The acid generator includes a compound having a sulfonate anion and a radiation-decomposable phosphonium cation, the sulfonate anion comprising SO ₃ ^- and a hydrogen atom or an electron donating group bonded to a carbon atom at the α position of the SO ₃ ^- , It is one in which an electron withdrawing group is bonded to a carbon atom at the β position.

The acid generating system can improve the radiation-sensitive resin composition containing the same LWR performance. Therefore, the acid generator can be suitably used as a component of the radiation sensitive resin composition.

<compound>

The compound has a sulfonate anion and a radiation-decomposable phosphonium cation, the sulfonate anion comprising SO ₃ ^- and a hydrogen atom or an electron donating group on the carbon atom at the α position of the SO ₃ ^- , a carbon at the β position It is one of the electron-withdrawing groups bonded to the atom.

Since this compound has the above properties, it can be suitably used as the acid generator.

The acid generator and the compound are described in the item of [B] acid generator of the radiation sensitive resin composition.

[Examples]

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited by the examples. The measurement methods of various physical property values are as follows.

[Mw and Mn]

The Mw and Mn of the polymer were measured by gel permeation chromatography under the following conditions using a GPC column (G2000HXL 2, G3000HXL 1 , G4000HXL 1 , manufactured by Tosoh Corporation).

Column temperature: 40 ° C

Precipitation solvent: tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd.)

Flow rate: 1.0 mL / min

Sample concentration: 1.0% by mass

Sample injection amount: 100 μL

Detector: differential refractive index

Reference material: monodisperse polystyrene

[ ¹ H-NMR analysis and ¹³ C-NMR analysis]

¹ H-NMR analysis and ¹³ C-NMR analysis were carried out by using a nuclear magnetic resonance apparatus (JNM-EX270, manufactured by JEOL Ltd.).

<Synthesis of Compounds> [Example 1] (Synthesis of Compound (B1-1))

The compound represented by the following formula (B1-1) was synthesized according to the following reaction scheme.

(Synthesis of Compound (m-2))

2-Bromo-3,3,3-trifluoropropan-1-ol (the above compound (m-1)) 5.0 g (26 mmol), Na ₂ SO ₄ 6.5 g (52 mmol) and H were added to a 200 mL eggplant flask. ₂ O 40 mL, and stirred at 85 ° C for 48 hours under a nitrogen atmosphere. After cooling to room temperature, 7.5 g (25 mmol) of triphenylsulfonium chloride and 120 mL of dichloromethane were added to the reaction solution, and the mixture was stirred at room temperature for 3 hours. After completion of the reaction, only the organic layer was separated and taken out, and the separated organic layer was washed three times with water 20 mL, and dried over anhydrous magnesium sulfate. Then, the residue obtained by concentrating under reduced pressure was purified by silica gel column chromatography (developing solvent: dichloromethane / MeOH = 10/1 (volume ratio)) to give compound (m-2) 6.2 g ( Yield 52%).

(Synthesis of Compound (B1-1))

5.0 g (11 mmol) of the obtained compound (m-2), 1.2 g (12 mmol) of triethylamine, and 0.13 g (1.1 mmol) of N,N-dimethyl-4-aminopyridine were added to a 300 mL reaction flask. After 100 mL of dichloromethane, the dichloromethane solution was cooled to 0 ° C, and a solution obtained by dissolving 3.3 g (17 mmol) of 1-adamantane ruthenium chloride in 30 mL of dichloromethane was dropwise added thereto. Thereafter, the mixture was stirred at 40 ° C for 20 hours. After completion of the reaction, the reaction solution was washed with water and saturated brine, and the organic layer was dried over anhydrous magnesium sulfate. Then, the residue obtained by concentrating under reduced pressure was purified by silica gel column chromatography (developing solvent: dichloromethane / MeOH = 12 / 1 (volume ratio)) to obtain compound (B1-1) 3.3 g ( Yield 49%).

The ¹ H-NMR data of the obtained compound (B1-1) is shown below.

¹ H-NMR (CDCl ₃ ) δ: 1.63-1.93 (m, 15H), 3.20 (m, 2H, CH ₂ ), 6.00 (m, 1H, CH), 7.67-7.83 (m, 15H)

[Example 2] (Synthesis of Compound (B1-2))

In the same manner as in Example 1, except that the compound represented by the following formula (m-3) was used instead of the 1-adamantanecarbonyl fluorene chloride, the following formula (B1-2) was obtained. The compound represented by 2.7 g (yield 45%).

The ¹ H-NMR data of the obtained compound (B1-2) is shown below.

¹ H-NMR (CDCl ₃ ) δ: 1.00 (s, 6H, CH ₃ ), 1.25 (s, 3H, CH ₃ ), 1.70 (m, 1H, CH), 1.93 (m, 2H, CH), 2.16 ( m, 1H, CH), 3.20 (m, 2H, CH ₂ ), 6.00 (m, 1H, CH), 7.67-7.83 (m, 15H)

[Example 3] (Synthesis of Compound (B1-3))

The compound represented by the following formula (B1-3) was synthesized according to the following reaction scheme.

To a 500 mL eggplant type flask, 4.5 g (15.6 mmol) of the above compound (m-4), 2.1 g (20.3 mmol) of NaHSO ₃ , 75 mL of MeOH, 25 mL of CH ₃ CN, and 75 mL of H ₂ O were added, and the mixture was stirred at 60 ° C under a nitrogen atmosphere. hour. After completion of the reaction, the solution was concentrated under reduced pressure until the amount of the solution was about 1/4. Thereafter, 3.7 g (12.5 mmol) of triphenylsulfonium chloride and 100 mL of dichloromethane were added, and the mixture was stirred at room temperature for 5 hours. After completion of the reaction, only the organic layer was separated and taken out, and the organic layer separated and separated was washed three times with 30 mL of water and dried over anhydrous magnesium sulfate. Thereafter, the residue obtained by concentrating under reduced pressure was purified by silica gel column chromatography (developing solvent: methylene chloride / MeOH = 12 / 1 (volume ratio)) to obtain compound (B1-3) 3.8 g ( Yield 38%).

The ¹ H-NMR data of the obtained compound (B1-3) is shown below.

¹ H-NMR (CDCl ₃ ) δ: 1.35 (s, 3H, CH ₃ ), 1.63-1.93 (m, 14H), 3.12 (m, 2H, CH ₂ ), 3.90 (m, 1H, CH), 7.67- 7.83 (m, 15H)

[Example 4] (Synthesis of Compound (B1-4))

In the same manner as in Example 3, except that the compound represented by the following formula (m-5) was used instead of the compound (m-4), the following formula (B1-4) was obtained. The compound represented by 2.1 g (yield 34%).

[化34]

The ¹ H-NMR data of the obtained compound (B1-4) is shown below.

¹ H-NMR (CDCl ₃ ) δ: 1.65-1.81 (m, 2H), 2.06 (m, 2H), 2.59 (m, 2H), 3.20 (m, 3H), 3.90 (m, 1H, CH), 4.60 (m, 2H), 7.67-7.83 (m, 15H)

[Example 5] (Synthesis of Compound (B1-5))

In the same manner as in Example 3 except that the compound represented by the following formula (m-6) was used instead of the compound (m-4), the following formula (B1-5) was obtained. The compound represented by 0.8 g (yield 19%).

The ¹ H-NMR data of the obtained compound (B1-5) is shown below.

¹ H-NMR (CDCl ₃ ) δ: 1.28 (s, 3H, CH ₃ ), 3.20 (m, 2H, CH ₂ ), 3.62 (m, 1H, CH), 4.21 (m, 2H, CH ₂ ), 7.67 -7.83 (m, 15H)

[Example 6] (Synthesis of Compound (B1-6))

In Example 1, in place of 2-bromo-3,3,3-trifluoropropan-1-ol, 3-bromo-4,4,4-trifluorobutan-2-ol was used instead (the following formula (m-7) the compound represented by the formula (m-7), and substituted 1-adamantanylcarbonyl ruthenium chloride and 1-cyclohexylcarbonyl ruthenium chloride (the compound represented by the following formula (m-8)), and other examples (1) 1.2 g (yield 24%) of the compound represented by the following formula (B1-6) was obtained in the same manner.

The ¹ H-NMR data of the obtained compound (B1-6) is as follows.

¹ H-NMR (CDCl ₃ ) δ: 1.25 (m, 3H), 1.40-1.98 (m, 10H, CH ₂ ), 2.27 (m, 1H, CH), 3.09 (m, 1H, CH), 5.97 (m) , 1H, CH), 7.67-7.83 (m, 15H)

[Example 7] (Synthesis of Compound (B1-7))

5.0 g (20.4 mmol) of o-(trifluoromethyl)benzenesulfonium chloride and 30 mL of dioxane were added to a 300 mL reaction flask, and the mixture was cooled to 0 ° C under a nitrogen atmosphere. An aqueous solution in which 1.0 g (24.5 mmol) of NaOH was dissolved in 60 mL of H ₂ O was slowly added dropwise thereto. Thereafter, the mixture was stirred at 0 ° C for 1 hour. After completion of the reaction, a predetermined concentration of HCl aqueous solution was gradually added dropwise to adjust the pH of the reaction solution to 7. Next, the concentration is adjusted to a concentration of 2/3 until the liquid amount of the reaction solution is concentrated under reduced pressure. To this, 8.5 g (28.6 mmol) of triphenylsulfonium chloride and 150 mL of dichloromethane were added, and the mixture was stirred at room temperature for 5 hours. After completion of the reaction, only the organic layer was separated and taken out, and the organic layer separated and separated was washed three times with 40 mL of water and dried over anhydrous magnesium sulfate. Thereafter, the residue obtained by concentrating under reduced pressure was purified by silica gel column chromatography (developing solvent: methylene chloride / MeOH = 12 / 1 (volume ratio)) to give compound (B1-7) 3.2 g. (Yield 32%).

The ¹ H-NMR data of the obtained compound (B1-7) is as follows.

¹ H-NMR (CDCl ₃ ) δ: 7.32-7.40 (m, 3H), 7.62-7.83 (m, 16H)

<[A] Synthesis of Polymers> [Synthesis Example 1] (Synthesis of Polymer (A-1))

14.2 g (35 mol%) of the following compound (m-9), 9.0 g (15 mol%) of the compound (m-10), and 26.8 g (50 mol%) of the compound (m-11) were dissolved in 100 g. After 2-butanone, 1.98 g of 2,2'-azobisisobutyronitrile was dissolved to prepare a monomer solution. 50 g of 2-butanone was placed in a 500 mL three-necked flask and rinsed with nitrogen for 30 minutes. After the nitrogen purge, the 2-butanone in the three-necked flask was stirred and heated to 80 ° C at the same time. Next, the above-prepared monomer solution was added dropwise over a period of 3 hours using a dropping funnel. After the completion of the dropwise addition, the mixture was further stirred at 80 ° C for 3 hours. After the completion of the polymerization, the reaction solution was cooled by water to be cooled to 30 ° C or lower. Then, the polymerization reaction liquid was poured into 1,000 g of methanol to precipitate a white powder, and then the mixture was separated by filtration. The white powder which had been separated by filtration was washed twice with 200 g of methanol, and then separated by filtration. Next, the obtained white powder polymer was dried at 50 ° C for 17 hours to obtain a polymer (A-1) (yield 38 g, yield 76%). This polymer (A-1) had Mw of 7,300 and Mw/Mn of 1.42. Further, as a result of ¹³ C-NMR analysis, the structural unit derived from the compound (m-9): the structural unit derived from the compound (m-10): the content ratio of the structural unit derived from the compound (m-11) was 36. :11:53 (% of Moer).

<[D] Synthesis of Polymers> [Synthesis Example 2] (Synthesis of Polymer (D-1))

21.5 g (70 mol%) of the following compound (m-12) and 8.5 g (30 mol%) of the compound (m-13) were dissolved in 30 g of 2-butanone, and then 2,2'-even was added. 1.38 g of nitrogen diisobutyronitrile was prepared to prepare a monomer solution. On the other hand, 30 g of 2-butanone was placed in a 200 mL three-necked flask and rinsed with nitrogen for 30 minutes. After the nitrogen purge, the 2-butanone in the three-necked flask was stirred and heated to 80 ° C at the same time. Next, the above-prepared monomer solution was dropped into the dropping funnel over a period of 3 hours using a dropping funnel. After the completion of the dropwise addition, the mixture was further stirred at 80 ° C for 3 hours. After the completion of the polymerization, the reaction solution was cooled by water to be cooled to 30 ° C or lower. Then, the polymerization reaction liquid was distilled under reduced pressure, and the mixture was concentrated to a mass of 45 g. Thereafter, the concentrated polymerization reaction liquid was placed in a mixture of 225 g of methanol/water (1/1 by volume) to precipitate a white powder, which was separated by decantation. The separated white powder was washed with a slurry of 45 g of methanol twice, and then separated by filtration. The obtained white powder polymer was dried at 50 ° C for 17 hours to obtain a polymer (D-1) (amount of 13.5 g, a yield of 45%). The polymer (D-1) had a Mw of 7,700 and a Mw/Mn of 1.44. Further, as a result of ¹³ C-NMR analysis, the structural unit derived from the compound (m-12): the content ratio of the structural unit derived from the compound (m-13) was 69:31 (mol%).

<Modulation of Radiation-Linear Resin Composition>

The components used in the preparation of the radiation sensitive resin composition are as follows.

[[B]acid generator] (Compound (I))

Compounds (B1-1) to (B1-7) synthesized in the above Examples 1 to 7

(other acid generators)

a compound represented by the following formula (B2-1) to (B2-5)

[[C] Acid Diffusion Control Agent]

C-1: 2-phenylbenzimidazole (compound represented by the following formula (C-1))

C-2: N-t-pentyloxycarbonyl-4-hydroxypiperidine (compound represented by the following formula (C-2))

C-3: triphenyl sulphate (a compound represented by the following formula (C-3))

C-4: triphenylsulfonium 10-camphorsulfonate (compound represented by the following formula (C-4))

[[E]solvent]

E-1: propylene glycol monomethyl ether acetate

E-2: cyclohexanone

E-3: γ-butyrolactone

[Embodiment 8]

100 parts by mass of the polymer (A-1) as the [A] polymer, 5 parts by mass of (B1-1) as the [B] acid generator, and 6 parts by mass of (B2-4), as the [C] acid 1.2 parts by mass of (C-1) of the diffusion controlling agent, 3 parts by mass of the polymer (D-1) as the [D] polymer, and (E-1) 2,400 parts by mass of the [E] solvent, (E- 2) 1,000 parts by mass and (E-3) 30 parts by mass were mixed, and then filtered using a filter having a pore size of 0.05 μm to obtain a radiation sensitive resin composition (J-1).

[Examples 9 to 20 and Comparative Examples 1 to 6]

The radiation sensitive resin compositions (J-2) to (J-13) and (CJ-1) were obtained in the same manner as in Example 8 except that the components of the type and the content shown in Table 1 were used. (CJ-6).

<evaluation>

The following evaluations were carried out using the above-described respective radiation-sensitive resin compositions prepared. The evaluation results are systematically shown in Table 1.

[LWR performance]

The photoresist underlayer film forming composition (ARC66, manufactured by Nissan Chemical Industries, Ltd.) was applied onto the surface of the wafer by 12% by selective coating. Next, baking was performed at 205 ° C for 60 seconds to form a photoresist underlayer film having a film thickness of 105 nm. On the resist film, each of the radiation-sensitive resin compositions prepared above was spin-coated, and PB was dried at 100 ° C for 50 seconds, and then cooled at 23 ° C for 30 seconds to form a photoresist film having a film thickness of 90 nm. Next, an ArF liquid immersion exposure apparatus (S610C, manufactured by NIKON) was used to project a BrightField map of 40 nm line/80 nm pitch under optical conditions of NA: 1.30, Outerσ/innerσ=0.977/0.782, Dipole, and v-polarized illumination. The type is masked for exposure. Thereafter, PEB was carried out at 105 ° C for 50 seconds using a hot plate. Next, using a GP nozzle of a developing unit, a 2.38 mass% aqueous solution of tetramethylammonium hydroxide was used as a developing solution for 10 seconds, and was washed with ultrapure water. The substrate on which the photoresist pattern was formed was obtained by spin drying at 2,000 rpm and 15 seconds of shaking. At this time, the exposure amount of the photoresist pattern capable of forming a 40 nm line/80 nm pitch was set as the optimum exposure amount, and the optimum exposure amount was set to the sensitivity (mJ/cm ² ). Using a length measuring SEM (CG4000, manufactured by Hitachi, Ltd.), the photoresist pattern of the resolved 40 nm line/80 nm pitch at the optimum exposure amount was observed from the upper part of the pattern, and the measurement line width was ten at any fixed point. The degree of distribution of this measured value is set to a value represented by 3σ and set to LWR (nm). The smaller the value, the better the uniformity of the line width of the pattern after development.

As is clear from the results of Table 1, it is found that the LWR of the photoresist pattern formed of the radiation sensitive resin composition is excellent.

[Industrial availability]

According to the radiation sensitive resin composition and the photoresist pattern forming method of the present invention, a photoresist pattern having a small LWR can be formed. The acid generator of the present invention can be suitably used as a component of a radiation sensitive resin composition, and its LWR performance can be improved. The compound of the present invention can be suitably used as the acid generator. Therefore, these can be suitably used in the lithography step of a semiconductor manufacturing process, such as a semiconductor manufacturing process which is expected to be further refined in the future.

Claims (12)

A radiation sensitive resin composition containing a polymer having a structural unit containing an acid dissociable group and an acid generator; the acid generator comprising a compound having a sulfonate anion and a radiation-decomposable phosphonium cation, the sulfonate containing anionic SO ₃ ^-, and thereto SO ₃ ^- or a bond for a hydrogen atom on the α carbon atom of the electron-position, the position on the β carbon atom bonded to a group formed by electron withdrawing. The radiation-sensitive resin composition of claim 1, wherein the compound has a group represented by the following formula (1-1) or (1-2); In the formulae (1-1) and (1-2), R ¹ and R ² each independently represent a hydrogen atom or a monovalent electron-donating group; R ³ is a monovalent electron withdrawing group; and R ⁴ is a hydrogen atom or 1 The hydrocarbon group of the valence; R ¹ to R ⁴ may represent a ring structure in which two or more of these are bonded to each other and bonded to the carbon atom to be bonded thereto; and M ⁺ is a monovalent radiation-decomposable phosphonium cation. The radiation-sensitive resin composition of claim 2, wherein the compound is represented by the following formula (2); In the formula (2), Z is a group represented by the above formula (1-1) or (1-2); X is a linking group of (n+1) valence; n is an integer of 1 to 3; when n is 1 , X may also be a single bond; R ⁵ is a hydrogen atom or a monovalent organic group; when n is 2 or more, the plural R ⁵ may be the same or different; Z, X and R ⁵ may also represent such a A ring structure composed of two or more of them combined with each other. The radiation sensitive linear resin composition of claim 3, wherein n in the above formula (2) is 1, and the linking group of the above X is a single bond, a divalent hydrocarbon group, -O-, -COO-, -NR-, -CONH-, -S-, -SO ₂ - or -SO ₃ -, R is a monovalent hydrocarbon group. The radiation-sensitive resin composition of claim 2, wherein the compound is a polymer having a structural unit represented by the following formula (3). In the formula (3), Z is a group represented by the above formula (1-1) or (1-2); Y is a divalent linking group; and R ⁶ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Z and Y may also represent the ring structure formed by the combination of these. The radiation sensitive resin composition according to any one of Claims 1 to 5, wherein the electron-donating group is a hydrocarbon group or an oxygen hydrocarbon group (oxyhydrocarbon) or amine group. The radiation sensitive resin composition according to any one of Claims 1 to 6, wherein the electron withdrawing group is a cyano group, a fluorine atom or a fluorinated hydrocarbon group. The radiation sensitive resin composition according to any one of claims 1 to 7, wherein the radiation-decomposable phosphonium cation is a phosphonium cation or a phosphonium cation. The radiation sensitive resin composition according to any one of Claims 1 to 8, wherein the structural unit containing the acid dissociable group is represented by the following formula (4); In the formula (4), R ⁷ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; R ⁸ is a monovalent hydrocarbon group having 1 to 20 carbon atoms; and R ⁹ and R ¹⁰ are each independently a carbon number 1~ a linear hydrocarbon group of 10 valence or an alicyclic hydrocarbon group having a carbon number of 3 to 20, or a group of these groups bonded to each other to form an alicyclic ring having 3 to 20 carbon atoms together with the carbon atoms bonded thereto structure. A photoresist pattern forming method, comprising the steps of forming a photoresist film, exposing the photoresist film, and The step of developing the above-mentioned exposed photoresist film, and the above-mentioned photoresist film is formed by the radiation-sensitive resin composition of any one of Claims 1 to 9. An acid generator comprising a compound having a sulfonate anion and a radiation-decomposable phosphonium cation, wherein the sulfonate anion is a group comprising SO ₃ ^- , and a hydrogen atom is bonded to a carbon atom at the alpha position of the SO ₃ ^- or An electron-donating group is obtained by bonding one electron-withdrawing group to a carbon atom at the β-position. A compound having a sulfonate anion and a radiation-decomposable phosphonium cation, wherein the sulfonate anion is a group comprising SO ₃ ^- , and a hydrogen atom or an electron-donating group is bonded to a carbon atom of the α-position of the SO ₃ ^- The carbon atom at the β position is bonded to one electron-withdrawing group.