TW201437749A - Radiation-sensitive resin composition, resist pattern forming method, radiation-sensitive acid generator and compound - Google Patents

Abstract

The present invention is a radiation-sensitive resin composition which contains a radiation-sensitive acid generator and a polymer having a structural unit that contains an acid-cleavable group, and wherein the radiation-sensitive acid generator contains a compound represented by formula (1). In formula (1), each of R1 and R2 independently represents a monovalent organic group having 1-20 carbon atoms; each of R3, R4 and R5 independently represents a hydrogen atom or a monovalent organic group having 1-20 carbon atoms; the organic groups may combine together to form a ring structure having 1-20 carbon atoms together with a carbon atom to which the organic groups are bonded; n represents an integer of 1-4; and M+ represents a monovalent radiation-decomposable onium cation.

Description

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

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

The radiation-sensitive resin composition used in the microfabrication microfabrication generates an acid in the exposed portion by irradiation of a far-ultraviolet light such as ArF excimer laser light, KrF excimer laser light, or an electron beam such as an electron beam. By the chemical reaction using the acid as a catalyst, the dissolution rate of the exposed portion and the unexposed portion to the developer is made different, and a resist pattern is formed on the substrate.

With the advancement of microfabrication technology, it is required to further improve the resolution of the radiation sensitive resin composition. In response to this request, various types of structures have been examined for the acid generators used in the composition (see Japanese Laid-Open Patent Publication No. 2002-131897, JP-A-2003-140331, and JP-A-2009-80474).

However, recently, the radiation-sensitive resin composition is not only excellent in resolution, but also requires LWR indicating the uniformity of pattern line width. (Line Width Roughness) performance, MEEF (Mask Error Enhencement Factor), which is representative of the mask size of the pattern line width, is excellent in performance, and is also required to ensure process stability. High precision resist pattern. However, the above conventional radiation-sensitive resin composition cannot satisfy these requirements. Further, since the above-mentioned conventional acid generator is used, the formed resist pattern tends to have a tip loss or the like, and therefore it is required to increase the squareness of the cross-sectional shape.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2002-131897

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2003-140331

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2009-80474

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 RTH performance, MEEF performance, and cross-sectional shape.

In order to solve the above problems, a radiation sensitive resin composition comprising: a polymer having a structural unit containing an acid dissociable group (hereinafter also referred to as "[A] polymer"), and a radiation sensitive line An acid generator (hereinafter also referred to as "[B] acid generator"), and the sensitizing radioactive acid generator contains a compound represented by the following formula (1) (hereinafter also referred to as "compound (I)"): (In the formula (1), R ¹ and R ^{2 are} each independently a monovalent organic group having 1 to 20 carbon atoms, and R ³ , R ⁴ and R ^{5 are} each independently a hydrogen atom or a carbon number of 1 to 20; The organic group, R ¹ to R ^{5 ,} may also represent a part of the ring structure of carbon number 1 to 20 which is composed of two or more of these bonds and the carbon atoms to be bonded together, and n is 1 to 4 Integer, M ⁺ is a monovalent radiation-decomposable ruthenium cation).

The method for forming a resist pattern of the present invention has the following steps: a step of forming a resist film, a step of exposing the resist film, and a step of developing the exposed resist film, and the resist film is The radiation-sensitive linear resin composition is formed.

The radiation sensitive acid generator of the present invention contains the compound (I).

The compound of the present invention is the compound (I).

Here, the "organic group" means a group containing at least one carbon atom.

According to the radiation sensitive resin composition and the resist pattern of the present invention, it is possible to form a resist pattern which exhibits excellent MEEF performance and has a small LWR and a rectangular shape in a cross-sectional shape. The radiation sensitive acid generator of the present invention can be preferably used as a component of a radiation sensitive resin composition. The compound of the present invention can be preferably used as the radiation-sensitive acid generator. Accordingly, these can be preferably used in a lithography step such as a semiconductor manufacturing process in which the prediction is progressing toward miniaturization.

<Inductive Radiation Resin Composition>

The radiation sensitive resin composition contains a [A] polymer and a [B] acid generator. The radiation sensitive resin composition may further contain a [C] acid diffusion controlling agent, a [D] fluorine atom-containing polymer (hereinafter also referred to as [D] polymer), and an [E] solvent as preferred components. Other optional components may be contained within the scope of the effects of the present invention. Hereinafter, each component will be described.

<[A]polymer>

[A] The polymer is a structural unit having an acid-dissociable group (hereinafter also A polymer called "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 dissociated by an acid action. The radiation sensitive resin composition is excellent in pattern formability by making the [A] polymer have a structural unit (I).

In addition to the structural unit (I), the polymer (A) preferably 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. It may also 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 is exemplified by a structural unit derived from an acid-dissociable ester of an unsaturated carboxylic acid, and a structural unit derived from an acid-dissociable ester of hydroxystyrene. In addition, from the viewpoint of improving the pattern formation property of the radiation-sensitive resin composition, it is preferably a structural unit represented by the following formula (2) (hereinafter also referred to as "structural unit (I-1)"). .

In the above formula (2), R ⁶ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, and R ⁷ is a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic ring having 3 to 20 carbon atoms. The hydrocarbon group, R ⁸ and R ^{9 are} each independently a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or means that the groups are bonded to each other and bonded thereto. The carbon atoms together constitute an alicyclic structure having a carbon number of 3 to 20.

The above R ⁶ is preferably a hydrogen atom or a methyl group from the viewpoint of obtaining copolymerization property of the monomer of the structural unit (I), and more preferably a methyl group.

The above-mentioned chain hydrocarbon group having 1 to 10 carbon atoms represented by R ⁷ to R ⁹ is exemplified by, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, 2-methylpropyl group, 1-methyl group. An alkyl group such as a propyl group or a tributyl group; an alkenyl group such as a vinyl group, a propylene group or a butenyl group; an alkynyl group such as an ethynyl group, a propynyl group or a butynyl group; and the like.

The alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ⁷ to R ⁹ is exemplified by a monocyclic cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group or a cyclohexyl group; a norbornyl group and an adamantane group; a polycyclic cycloalkyl group such as a tricyclic fluorenyl group or a tetracyclododecyl group; a cycloalkenyl group such as a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group or a cyclohexenyl group; a norbornene group; a polycyclic cycloalkenyl group such as a cyclodecenyl group or a tetracyclododecenyl group.

The alicyclic structure in which the chain hydrocarbon group and the alicyclic hydrocarbon group represented by R ⁷ to R ⁹ are bonded to each other and the carbon atoms to be bonded together is represented by, for example, a cyclopropane structure. a monocyclic naphthenic structure such as a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a cycloheptane structure or a cyclooctane structure; a monocyclic cycloolefin structure such as a cyclopentene structure or a cyclohexene structure; a polycyclic naphthenic structure such as a ferrocene structure, an adamantane structure, a tricyclodecane structure or a tetracyclododecane structure; a polycyclic cycloolefin structure such as a norbornene structure or a tricyclic terpene structure.

Among these, a monocyclic naphthenic structure and a polycyclic naphthenic structure are preferred, and a cyclopentane structure or an adamantane structure is more preferable.

In the above, from the viewpoint of easiness of dissociation of the acid dissociable group, R ^{7 is} preferably an alkyl group having 1 to 4 carbon atoms, and R ⁸ and R ⁹ are bonded to each other together with the carbon atoms bonded thereto. a polycyclic or monocyclic naphthenic structure, more preferably R ⁷ is a methyl group, an ethyl group, an isopropyl group, and R ⁸ and R ⁹ are bonded to each other together with the bonded carbon atoms to represent an adamantane structure and a ring. Pentane structure.

The structural unit (I-1) is, for example, a structural unit represented by the following formulas (2-1) to (2-4) (hereinafter, also referred to as "structural unit (I-1-1) to (I-1-) 4)") and so on.

In the above formulae (2-1) to (2-4), R ⁶ to R ⁹ have the same meanings as in the above formula (2). i and j are each independently an integer from 1 to 4.

i and j are preferably 1.

The structural unit (I-1) is exemplified by a structural unit represented by the following formula, and the like.

In the above formula, R ⁶ is synonymous with the above formula (2).

As the structural unit (I), it is preferable that the structural unit (I-1-1) and the structural unit (I-1-2) are preferable, and it is more preferably a structural unit having a cyclopentane structure and having an adamantane structure. The structural unit, more preferably a structural unit derived from 1-alkylcyclopentanyl (meth)acrylate, a structural unit derived from 2-alkyladamantyl (meth)acrylate, preferably derived from ( a structural unit of 1-methylcyclopentamethyl methacrylate, a structural unit derived from 1-ethylcyclopentyl (meth)acrylate, derived from 2-methyl (meth)acrylate The structural unit of the fundane ester, derived from the structural unit of 2-isopropyl hydroxyalkyl (meth) acrylate.

The content ratio of the structural unit (I) is preferably from 5 mol% to 95 mol%, more preferably from 20 mol% to 90 mol%, and more preferably the total structural unit constituting the [A] polymer. It is preferably 30% by mole to 80% by mole, preferably 35% by mole to 755% by mole. By setting the content ratio of the structural unit (I) to the above range, the pattern formation property of the radiation sensitive resin composition can be 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 further has a structural unit (II), and the solubility in the developer can be adjusted. As a result, the lithographic performance such as the resolution of the radiation-sensitive resin composition can be improved. Further, the adhesion between the resist pattern formed of the [A] polymer and the substrate can be improved.

The structural unit (II) is exemplified by a structural unit represented by the following formula, and the like.

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

With respect to the structural unit (II), among these, it is preferably a structural unit containing a lactone structure, more preferably a structural unit containing a norbornene lactone structure, and more preferably a (meth)acrylic acid norbornane. Lactone construction sheet Bit.

The content ratio of the structural unit (II) is preferably from 10 mol% to 80 mol%, more preferably from 20 mol% to 70 mol%, and more preferably all structural units constituting the [A] polymer. Good for 25 mol%~60 mol%. By setting the content ratio of the structural unit (II) to the above range, the lithographic performance such as the resolution of the radiation sensitive resin composition and the adhesion between the formed resist pattern and the substrate can be further improved.

[Other construction units]

The [A] polymer may have other structural units in addition to the above structural units (I) and (II). The other structural unit is exemplified by, for example, a structural unit containing a polar group (except for the structural unit (II)). [A] The polymer can further adjust the solubility to the developer 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, a sulfonylamino group and the like. Among these, a hydroxyl group and a carboxyl group are preferred, and a hydroxyl group is more preferred.

The structural unit having the polar group is exemplified by 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 from 0 mol% to 40 mol%, more preferably from 0 mol% to 30 mol%, based on the entire structural unit constituting the [A] polymer. More preferably 0% by mole to 20% by mole. By setting the content ratio of the structural unit having a polar group to 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 structural unit containing the above polar group as another structural unit. The content ratio of the structural unit is preferably 30 mol% or less, more preferably 20 mol% or less, based on the entire structural unit constituting the [A] polymer.

<[A] Synthesis Method of Polymer>

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

The above radical polymerization initiators are exemplified by, for example, azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2' -Azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyric acid dimethyl ester, etc. A nitrogen-based radical initiator; a peroxide-based radical polymerization initiator such as benzammonium peroxide, tert-butyl hydroperoxide or cumyl hydroperoxide. Among these, AIBN, dimethyl 2,2'-azobisisobutyrate is preferred, and more preferably AIBN. These radical initiators may be used alone or in combination of two or more.

The solvent used in the above polymerization is exemplified by, for example, n-pentane, n-hexane, n-heptane, n-octane, n-decane, n-decane. Alkane; cyclohexanes such as cyclohexane, cycloheptane, cyclooctane, decahydronaphthalene, norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene; Halogenated hydrocarbons such as alkanes, bromohexanes, dichloroethanes, hexamethylene dibromide, chlorobenzene; saturated carboxylic acids such as ethyl acetate, n-butyl acetate, isobutyl acetate, methyl propionate Esters; ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone, and 2-heptanone; ethers such as tetrahydrofuran, dimethoxyethane, and diethoxyethane; An alcohol such as methanol, ethanol, 1-propanol, 2-propanol or 4-methyl-2-pentanol. The solvent used for 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.

[A] The weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) is not particularly limited, but is preferably 1,000 or more and 50,000 or less, more preferably 2,000 or more. More preferably, it is 30,000 or less, more preferably 2,500 or more and 15,000 or less, and most preferably 3,000 or more and 10,000 or less. When the Mw of the [A] polymer does not reach the above lower limit, the heat resistance of the obtained resist film may be lowered. [A] When the Mw of the polymer exceeds the above upper limit, the developability of the resist film may decrease. The situation.

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

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

GPC pipe column: 2 G2000HXL, 1 G3000HXL, 1 G4000HXL (above is TOSOH)

Column temperature: 40 ° C

Dissolution solvent: tetrahydrofuran (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 [A] polymer is preferably 70% by mass or more, more preferably 80% by mass or more, and still 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 radiation-sensitive linear acid generator containing the compound (I). The radiation sensitive resin composition is excellent in the RTR performance, the MEEF performance, and the cross-sectional shape by the inclusion of the [B] acid generator. Although the reason why the radiation-sensitive resin composition has the above-described configuration and exhibits the above-described effects is not necessarily clear, it is presumed as follows. That is, the sulfonate of the compound (I) is bonded to the R ¹ group bonded to a carbon atom adjacent to the CF ₂ chain of the sulfonate group, and the carbon atom adjacent to the carbon atom is bonded to the R ² group. . Thus, since the vicinity of the sulfonate group has a three-dimensional structure, the diffusion of the acid generated by the compound (I) is moderately suppressed. As a result, the LWR performance and the MEEF performance of the radiation-sensitive resin composition containing the compound (I) as an acid generator were improved. Further, since the compound (I) has the above-described specific structure and has a structure of three-dimensional mixing in the vicinity of the CF ₂ group, the surface layer which is biased in the resist film can be suppressed by having a fluorine atom, and as a result, the feeling is improved. The rectangular shape of the cross-sectional shape of the resist pattern formed by the radiation-linear resin composition.

[Compound (I)]

The compound (I) is represented by the following formula (1).

In the above formula (1), R ¹ and R ^{2 are} each independently a monovalent organic group having 1 to 20 carbon atoms, and R ³ , R ⁴ and R ^{5 are} each independently a hydrogen atom or a carbon number of 1 to 20 The organic group, R ¹ to R ^{5 ,} may also represent a part of the ring structure of carbon number 1 to 20 which is composed of two or more of these bonds and the carbon atoms to be bonded together, and n is 1 to 4 Integer, M ⁺ is a monovalent radiation-decomposable ruthenium cation.

The organic group having 1 to 20 carbon atoms represented by R ¹ to R ⁵ is, for example, a monovalent hydrocarbon group having 1 to 20 carbon atoms, a hetero atom-containing group having a hetero atom-containing group between carbon and carbon of the hydrocarbon group, The base or the like in which one or all of the hydrogen atoms of the hetero atom-containing group is substituted with a substituent.

The monovalent hydrocarbon group having 1 to 20 carbon atoms is exemplified by a chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a monovalent 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 vinyl group, a propenyl group or a butenyl group; an alkynyl group such as an ethynyl group, a propynyl group or a butynyl group; .

The above alicyclic hydrocarbon group is exemplified by 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 norbornyl group, an adamantyl group or a tricyclodecyl group; a monocyclic cycloalkenyl group such as a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group or a cyclohexenyl group; a polycyclic cycloalkenyl group such as a norbornene group or a tricyclodecenyl group;

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

The above hetero atom-containing groups are exemplified by, for example, -O-, -CO-, -NH-, -S-, a combination of these, etc.

Examples of the above substituents include a hydroxyl group, a carboxyl group, an oxyhydrocarbyl group, a carbonyloxyalkyl group, a decyl group, a decyloxy group, a cyano group, a nitro group, a ketone group (=O), and the like.

With respect to the above R ¹ , it is preferable to further improve the LWR performance, the MEEF performance, and the rectangular shape of the cross-sectional shape of the radiation-sensitive resin composition by more closely mixing the vicinity of the SO ₃ ^- or the like. The hydrocarbon group, the carbonyloxy hydrocarbon group, the oxyhydrocarbyl group, and the aliphatic heterocyclic group are preferably a hydrocarbon group from the viewpoint of improving the solubility of the compound (I) in an organic solvent, and from the viewpoint of easiness of synthesis of the compound (I). In other words, a carbonyloxy hydrocarbon group is preferred.

The above hydrocarbon group is more preferably an alicyclic hydrocarbon group or an aromatic hydrocarbon group, more preferably an alicyclic hydrocarbon group, more preferably a cycloalkyl group, more preferably a polycyclic cycloalkyl group, and most preferably an adamantyl group or a diamond. Alkylmethyl.

The above carbonyloxy hydrocarbon group is preferably a carbonyloxyalicyclic hydrocarbon group, more preferably a cycloalkyloxycarbonyl group, more preferably a polycyclic cycloalkyloxycarbonyl group, and most preferably a 2-adamantyloxy group. Carbonyl.

When the hydrocarbon group in the carbonyloxy hydrocarbon group of R ¹ is an acid dissociable group, the LWR performance, MEEF performance, and cross-sectional shape of the radiation sensitive resin composition can be further improved. This is because, for example, in the exposed portion, a carboxyl group is generated in the compound (I), and as a result, the contrast between the exposed portion and the unexposed portion is improved. The acid dissociable group is exemplified by, for example, the same as those exemplified as the acid dissociable group in the above [A] polymer. Among these, a hydrocarbon group having a carbon atom of 3 or less as a bond, preferably a cycloalkyl group having a carbon atom bonded to the bond, and more preferably a 2-alkyl-2-adamantane The group is preferably 2-methyl-2-adamantyl.

The above oxyhydrocarbyl group is preferably an oxyalicyclic hydrocarbon group, more preferably a cycloalkyloxy group, more preferably an adamantyloxy group.

The aliphatic heterocyclic group is preferably an aliphatic heterocyclic group having an oxygen atom as a ring-constituting atom, more preferably an oxycycloalkyl group, more preferably an oxycyclohexyl group.

The above R ^{2 is} preferably a hydrocarbon group, an oxyhydrocarbyl group or an aliphatic heterocyclic group from the viewpoint of more moderately inhibiting the diffusion of the acid generated from the compound (I) by having a volume and/or a polarity. The group having a β-diketone structure is more preferably a hydrocarbon group from the viewpoint of improving the solubility of the compound (I) in an organic solvent.

The above hydrocarbon group is preferably an alkyl group or a cycloalkyl group, more preferably an alkylcyclo group, more preferably a cyclopentyl group, a cyclohexyl group, an adamantyl group or an adamantylmethyl group, and most preferably a cyclopentyl group or a cyclohexyl group.

The above oxyhydrocarbyl group is preferably a cycloalkyloxy group, more preferably a cyclohexyloxy group.

The above aliphatic heterocyclic group is preferably an aliphatic heterocyclic group containing a sulfur atom as a ring-constituting atom, more preferably a dithiacycloalkyl group, more preferably a dithiahexyl group.

The above-mentioned group having a β-diketone structure is preferably a pentane-2,4-keto-3-yl group.

At least one of the above R ¹ and R ² is preferably a group having a cyclic structure. When the above R ¹ and/or R ² have a cyclic structure, the vicinity of the sulfonate group of the compound (I) is a three-dimensionally mixed structure, and the diffusion of the acid generated from the compound (I) can be more appropriately suppressed. Further, the surface layer of the compound (I) in the resist film can be further inhibited from being biased. As a result, the LWR performance and the MEEF performance of the radiation-sensitive resin composition and the rectangular shape of the cross-sectional shape of the formed resist pattern can be further improved. More preferably, both of R ¹ and R ² are groups having a cyclic structure.

The above R ³ , R ⁴ and R ^{5 are} preferably a hydrogen atom or a monovalent hydrocarbon group, more preferably a hydrogen atom or an alkyl group, and more preferably hydrogen from the viewpoint of easiness of synthesis of the compound (I). atom.

As for the above n, it is preferably 1 or 2, more preferably 1.

The above-mentioned monovalent radiation-decomposable phosphonium cation represented by M ⁺ is a cation which is decomposed by irradiation of radiation. In the exposed portion, a proton generated by decomposition of the radiation-decomposable phosphonium cation and a sulfonic acid anion (A) generate a sulfonic acid. Examples of the radiation include electromagnetic waves such as ultraviolet rays, far ultraviolet rays, extreme ultraviolet rays (EUV), X-rays, and gamma rays, and charged particle beams such as electron beams and α rays. Among them, far ultraviolet rays, EUV, electron beams are better, more preferably far ultraviolet rays, and more preferably KrF excimer laser light (248 nm), ArF excimer laser light (193 nm), preferably ArF excimer laser light. .

The radiation-decomposable phosphonium cation is exemplified by a radiation-decomposable phosphonium cation containing 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 S (sulfur) as an element and a phosphonium cation containing I (iodine) as an element are preferable, and a cation represented by the following formula (X-1) is more preferable. The cation represented by the formula (X-2) and the cation represented by the following formula (X-3).

In the above formula (X-1), R ^a1 , R ^a2 and R ^a3 each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon. 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 An unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. Each of k1, k2, and k3 is an integer of 0-5. When R ^a1 to R ^a3 and R ^P and R ^Q are plural, respectively, 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 them. 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 them. 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 composed of two or more of these groups 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 An unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. K6 and k7 are each independently an integer from 0 to 5. When R ^c1 , R ^c2 , R ^R and R ^S are each a complex number, the plural R ^c1 , R ^c2 , R ^R and R ^S may be the same or different.

The unsubstituted linear alkyl group represented by R ^a1 to R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 is exemplified by a methyl group, an ethyl group, a n-propyl group, an n-butyl group or the like.

The unsubstituted branched alkyl group represented by R ^a1 to R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 is exemplified by an isopropyl group, an isobutyl group, a second butyl group, a third butyl group or the like.

The unsubstituted aromatic hydrocarbon group represented by R ^a1 to R ^a3 , R ^c1 and R ^c2 is exemplified by an aryl group such as a phenyl group, a tolyl group, a xylyl group, a mesityl group or a naphthyl group; a benzyl group or a phenyl group; An arylalkyl group or the like.

The unsubstituted aromatic hydrocarbon group represented by R ^b1 and R ^b2 is exemplified by a phenyl group, a tolyl group, a benzyl group or the like.

The substituent which may be substituted for the hydrogen atom of the above alkyl group and the aromatic hydrocarbon group is exemplified by 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, a nitro group, an alkoxy group or an alkane group. An oxycarbonyl 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 more preferred.

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

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

K4 in the above formula (X-2) is preferably an integer of 0 to 2, more preferably 0 or 1, more preferably 1. K5 is preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0.

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

The above ruthenium cations are exemplified by cations represented by the following formulas (i-1) to (i-68).

In addition, the above ruthenium cation is exemplified by a cation represented by the following formulas (ii-1) to (ii-39).

The radiation-decomposable phosphonium cation is preferably a phosphonium cation represented by (i-1) and a phosphonium cation represented by (ii-1), more preferably a phosphonium cation represented by (i-1).

The compound (I) is a compound represented by the following formula (1-1) to (1-24) (hereinafter also referred to as "compound (I-1)~ (I-24)") and so on.

In the above formulae (1-1) to (1-24), M ⁺ is a monovalent radiation-decomposable phosphonium cation.

In the above, the LWR performance, the MEEF performance and the rectangular shape of the cross-sectional shape of the radiation-sensitive resin composition are further improved. Preferably, the compound (I-1) to (I-17) is preferred, and more preferably the compound (I-1), the compound (I-4), the compound (I-6), the compound (I-10), or the compound. (I-14) is more preferably a compound (I-1) or a compound (I-6).

<Synthesis method of compound (I)>

When the compound (I) in the above formula (1) is, for example, the compound (I') represented by the following formula (1') wherein R ⁵ is a hydrogen atom and n is 1, the compound (I) can be synthesized according to the following reaction scheme.

In the above reaction scheme, R ¹ and R ^{2 are} each independently a monovalent organic group having 1 to 20 carbon atoms. R ³ and R ^{4 are} each independently a hydrogen atom or an organic group having 1 to 20 carbon atoms. X is a halogen atom. M ⁺ is a monovalent radioactive decomposed phosphonium cation. Y ^- is a monovalent cation.

The compound represented by the above formula (a) is reacted with a Grignard reagent having an R ² group in a solvent such as tetrahydrofuran to obtain a compound represented by the above formula (b). Next, the compound (b) is reacted with a sulfonating agent in a solvent such as water in the presence of a base to obtain a sulfonate represented by the above formula (c). Next, the compound (c) is reacted with a salt compound containing a monovalent linear phosphonium cation represented by the above formula M ⁺ Y ^{- in a} solvent such as dichloromethane/water, whereby the above formula (1') is obtained. Expressed as a compound.

Examples of the sulfonating agent include sulfites such as sulfurous acid gas, sodium sulfite, potassium sulfite, calcium sulfite, barium sulfite, ammonium sulfite, and the like, hydrogen sulfites such as sodium hydrogen sulfite and potassium hydrogen sulfite. Dithionite such as sodium dithionite or potassium dithionite. Among these, sulfites are preferred, and sodium sulfite is more preferred.

Examples of the base include metal hydroxides such as sodium hydroxide, potassium hydroxide, calcium hydroxide, and magnesium hydroxide; metal carbonates such as sodium carbonate, potassium carboxylate, calcium carbonate, and magnesium carbonate; sodium hydrogencarbonate and hydrogencarbonate. a metal hydrogencarbonate such as potassium, a trimetallic phosphate such as trisodium phosphate or tripotassium phosphate; a diphosphoric acid dimetalate such as disodium hydrogen phosphate or dipotassium hydrogen phosphate; a phosphoric acid such as sodium dihydrogen phosphate or potassium dihydrogen phosphate; Dihydrogen metal salts, organic bases such as triethylamine and pyridine. Among these, metal hydrogencarbonate is preferred, and more preferably sodium hydrogencarbonate.

The compound (1) other than the compound (1') 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), within the range not impairing the effects of the present invention.

The above-mentioned other acid generator is not particularly limited as long as it is an acid generator other than the above compound (I), and examples thereof include an onium salt compound and an N-sulfonyloxyimine compound.

The onium salt compound is exemplified by, for example, an onium salt, a tetrahydrothiophene salt, a phosphonium salt, a phosphonium salt, a diazonium salt, a pyridinium salt or the like.

The onium salt is exemplified by, for example, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluorobutanesulfonate, triphenylsulfonium perfluorooctanesulfonate, triphenylsulfonium 2-bicyclo[ 2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenylsulfonium 2-bicyclo[2.2.1]hept-2-yl-1,1-difluoro Ethane sulfonate, triphenyl camphorsulfonate, 4-cyclohexylphenyldiphenylphosphonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylphosphonium hexafluoro-n-butane sulfonate Acid salt, 4-cyclohexylphenyldiphenylphosphonium perfluorooctane sulfonate, 4-cyclohexylphenyldiphenylfluorene 2-bicyclo[2.2.1]hept-2-yl-1,1, 2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyldiphenyl camphorsulfonate, 4-methanesulfonylphenyldiphenylphosphonium trifluoromethanesulfonate, 4-methanesulfonate Nonylphenyldiphenylphosphonium nonafluorobutane sulfonate, 4-methanesulfonylphenyldiphenylphosphonium perfluorooctane sulfonate, 4-methanesulfonylphenyldiphenylsulfonium 2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyldiphenyl camphorsulfonate, triphenyl 1,1,2,2-tetrafluoro-6-(1-adamantanecarbonyloxy)-hexane-1-sulfonic acid , triphenylsulfonium 1,1-difluoro-2-(adamantan-1-yl)-ethane-1-sulfonate, triphenylsulfonium 1,1-difluoro-2-(adamantane-1 -yloxycarbonyl Ethyl-1-sulfonate, triphenylsulfonium 1,1-difluoro-2-(adamantane-1-ylcarbonyloxy)ethane-1-sulfonate, and the like.

The tetrahydrothiophene sulfonium salt is exemplified by, for example, 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiophene trifluoromethanesulfonate, 1-(4-n-butoxynaphthalen-1-yl)tetra Hydrogenthiophene nonafluoro-n-butane sulfonate, 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiophene fluorene perfluorooctane sulfonate, 1-(4-n-butoxynaphthalene) -1-yl)tetrahydrothiophene 2-cyclobi[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1-(4-n-butoxynaphthalene- 1-yl)tetrahydrothiophene camphorsulfonate, 1-(6-n-butoxynaphthalen-2-yl)tetrahydrothiophene trifluoromethanesulfonate, 1-(6-n-butoxynaphthalene- 2-yl)tetrahydrothiophene nonafluoro-n-butane sulfonate, 1-(6-n-butoxynaphthalen-2-yl)tetrahydrothiophene fluorene perfluoro-n-octane sulfonate, 1-(6-positive Butoxynaphthalen-2-yl)tetrahydrothiophene 2-cyclobi[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1-(6-n-butyl Oxynaphthalen-2-yl)tetrahydrothiophene camphorsulfonate, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene trifluoromethanesulfonate, 1-(3, 5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene nonafluoro-n-butane sulfonate, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene fluorinated n-octane Alkane sulfonate, 1-(3,5-dimethyl-4-hydroxyl Phenyl)tetrahydrothiophene 2-cyclobi[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1-(3,5-dimethyl-4- Hydroxyphenyl) tetrahydrothiophene camphorsulfonate and the like.

The onium salt is exemplified by, for example, diphenylsulfonium trifluoromethanesulfonate, diphenylsulfonium nonafluorobutanesulfonate, diphenylphosphonium perfluorooctanesulfonate, diphenylphosphonium 2-bicyclopropane. [2.2.1] Hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, diphenyl camphorsulfonate, bis(4-t-butylphenyl)phosphonium Fluoromethanesulfonate, bis(4-t-butylphenyl)phosphonium nonafluorobutane sulfonate, bis(4-t-butylphenyl)phosphonium perfluoro-n-octane sulfonate, double 4-tert-butylphenyl)indole 2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, bis(4-t-butylphenyl) ) camphor sulfonate and the like.

The N-sulfonyloxyimide compound is exemplified by, for example, N-(trifluoromethanesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylimideimine, N-(nine Fluorine butane sulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylimenine, N-(perfluoro-n-octanesulfonyloxy)bicyclo[2.2.1] Hg-5-ene-2,3-dicarboxylimenine, N-(2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) Bicyclo[2.2.1]hept-5-ene-2,3-dicarboxyarsenine, N-(2-(3-tetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]dodecyl] -1,1-difluoroethanesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylimenine, N-(camanosylsulfonyloxy)bicyclo[2.2. 1] Hept-5-ene-2,3-dicarboxylimenine and the like.

The content of the [B] acid generator is preferably from 0.1 part by mass to 30 parts by mass, more preferably from 0.5 part by mass to 25 parts by mass, even more preferably from 1 part by mass to 20 parts by mass per 100 parts by mass of the [A] polymer. Parts by mass. By setting the content of the [B] acid generator to the above range, the sensitivity of the radiation sensitive resin composition can be improved, and as a result, the RWR performance, the MEEF performance, and the rectangular shape of the cross-sectional shape can be improved.

The content of the compound (I) in the [B] acid generator is preferably from 20% by mass to 100% by mass, more preferably from 50% by mass to 100% by mass, even more preferably from 90% by mass to 100% by mass, most preferably Good for 100% by mass. By setting the content of the compound (I) to the above range, the LWR performance, MEEF performance, and profile of the radiation sensitive resin composition can be further improved. The shape of the rectangle.

The content of the compound (I) in the radiation sensitive resin composition is preferably from 0.1 part by mass to 30 parts by mass, more preferably from 0.5 part by mass to 25 parts by mass, based on 100 parts by mass of the [A] polymer. It is preferably 1 part by mass to 20 parts by mass. By setting the content of the compound (I) to the above range, the LWR performance, the MEEF performance, and the cross-sectional shape of the radiation-sensitive resin composition can be improved in squareness.

<[C] Acid Diffusion Control Agent>

The radiation sensitive resin composition may also contain a [C] acid diffusion controlling agent as needed.

[C] The acid diffusion control agent controls the diffusion of the acid generated from the [B] acid generator by the exposure agent in the resist film, and exhibits an effect of suppressing poor chemical reaction in the unexposed region, thereby further improving the obtained radiation sensitivity. The storage stability of the resin composition, and further improving the resolution as a resist, while suppressing the line width variation of the resist pattern due to the change in the standing time from exposure to development processing, and obtaining a feeling of excellent process stability A linear resin composition.

The [C] acid diffusion controlling agent is exemplified by a compound represented by the following formula (3) (hereinafter also referred to as "nitrogen-containing compound (I)"), and a compound having two nitrogen atoms in the same molecule (hereinafter also referred to as The "nitrogen-containing compound (II)"), a compound having three nitrogen atoms (hereinafter also referred to as "nitrogen-containing compound (III)"), a compound containing a mercapto group, a urea compound, a nitrogen-containing heterocyclic compound, and the like.

In the above formula (3), R ¹² , R ¹³ and R ¹⁴ each independently represent a hydrogen atom, a linear, branched or cyclic alkyl group, an aryl group or an aralkyl group which may be substituted.

The nitrogen-containing compound (I) is exemplified by monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; trialkylamines such as triethylamine and tri-n-pentylamine; and aniline. An aromatic amine such as 6-diisopropylaniline. Among these, a trialkylamine or an aromatic amine is preferred, and more preferably tri-n-pentylamine or 2,6-diisopropylaniline.

The nitrogen-containing compound (II) is exemplified by ethylenediamine, N, N, N', N'-tetramethylethylenediamine and the like.

The nitrogen-containing compound (III) is exemplified by a polyamine compound such as polyethylenimine or polyallylamine; a polymer such as dimethylaminoethyl acrylamide or the like.

The compounds containing amidino group are exemplified by, for example, formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-di Methylacetamide, acetamide, benzamide, pyrrolidone, N-methylpyrrolidone, and the like.

The urea compound is exemplified by, for example, urea, methyl urea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenyl. Urea, tri-n-butyl thiourea, and the like.

The nitrogen-containing heterocyclic compound is exemplified by pyridines such as pyridine and 2-methylpyridine; morpholines such as N-propylmorpholine and N-(undecylcarbonyloxyethyl)morpholine; 2-benzene Imidazoles such as benzimidazole; pyrazine, pyrazole, and the like. Among these, N-(undecylcarbonyloxyethyl)morpholine is preferred.

Further, as the above nitrogen-containing organic compound, a compound having an acid dissociable group can also be used. The nitrogen-containing organic compound having an acid-dissociable group is exemplified by, for example, N-tert-butoxycarbonylpiperidine, N-tert-butoxycarbonylimidazole, N-tert-butoxycarbonylbenzimidazole, N- Tributoxycarbonyl-2-phenylbenzimidazole, N-(t-butoxycarbonyl)di-n-octylamine, N-(t-butoxycarbonyl)diethanolamine, N-(third butoxide) Carbocarbonyl)dicyclohexylamine, N-(t-butoxycarbonyl)diphenylamine, N-tert-butoxycarbonyl-4-hydroxypiperidine, N-third pentyloxycarbonyl-4-hydroxyl Piperidine and the like. Among these, N-t-butoxycarbonyl-4-hydroxypiperidine and N-third pentyloxycarbonyl-4-hydroxypiperidine are preferred, and more preferably N-tert-butoxycarbonyl-4. - Hydroxy piperidine.

Further, as the [C] acid diffusion controlling agent, a photocracking base which is photosensitive by exposure and produces a weak acid can also be used. The photocracking base is exemplified by, for example, an onium salt compound which loses acid diffusion controllability by exposure decomposition. The onium salt compound is, for example, an onium salt compound represented by the following formula (4), an onium salt compound represented by the following formula (5), and the like.

In the above formula (4) and formula (5), 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 OH ^- , R ^β -COO ^- , R ^β -SO ₃ ^- or an anion represented by the following formula (X). However, R ^β is an alkyl group, an aryl group or an aralkyl group.

In the above formula (X), R ²⁰ is a linear or branched alkyl group having 1 to 12 carbon atoms or a linear or branched carbon number of 1 to 12 which is partially or wholly substituted by a fluorine atom. Alkoxy. u is an integer from 0 to 2.

The photocracking base is exemplified by a compound represented by the following formula.

The photocracking base is preferably a sulfonium salt, more preferably a triarylsulfonium salt, and more preferably a triphenylsulfonium salicylate or a triphenylphosphonium 10-camphorsulfonate.

The content of the [C] acid diffusion controlling agent is preferably from 0 part by mass to 20 parts by mass, more preferably from 0.1 part by mass to 15 parts by mass, even more preferably from 0.3 part by mass to 100 parts by mass of the [A] polymer. 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 (excluding the [A] polymer). The radiation sensitive linear resin composition contains the [D] polymer, so that when the resist film is formed, the distribution of the fluorine-containing polymer in the film is biased to the vicinity of the surface of the resist film. a tendency to inhibit the dissolution of the acid generator or the acid diffusion control agent during immersion exposure in. Moreover, by the water repellency characteristic of the [D] polymer, the contact angle of the resist film and the liquid immersion medium can be controlled to a desired range, and the generation of bubble defects can be suppressed. In addition, the back contact angle of the resist film and the liquid immersion medium can be increased, and scanning exposure can be performed at high speed without leaving water droplets. By including the [D] polymer in the radiation sensitive resin composition, a resist film suitable for the liquid immersion exposure method can be formed.

The polymer [D] is not particularly limited as long as it is a polymer having a fluorine atom, but preferably has a fluorine atom content (% by mass) higher than that of the [A] polymer in the radiation sensitive resin composition. When the fluorine atom content is higher than that of the [A] polymer, the above-described degree of partialization can be further improved, and characteristics such as water repellency and dissolution inhibition of the obtained resist film can be improved.

[D] The fluorine atom content of the polymer is preferably 1% by mass or more, more preferably 2% by mass to 60% by mass, still more preferably 4% by mass to 40% by mass, and most preferably 7% by mass to 30% by mass. %. When the fluorine atom content of the polymer [D] is less than the above lower limit, the hydrophobicity of the surface of the resist 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 of the polymer can be calculated.

The [D] polymer preferably has 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 of each of a structural unit (Da) and a structural unit (Db).

[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-, and R ^E has at least one fluorine atom. A monovalent chain hydrocarbon group having 1 to 6 carbon atoms or a monovalent aliphatic cyclic hydrocarbon group having 4 to 20 carbon atoms and having at least one fluorine atom.

The chain hydrocarbon group having 1 to 6 carbon atoms and having at least one fluorine atom represented by R ^E is exemplified by, for example, a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a perfluoroethyl group, and 2,2. 3,3,3-pentafluoropropyl, 1,1,1,3,3,3-hexafluoropropyl, perfluoro-n-propyl, perfluoroisopropyl, perfluoro-n-butyl, perfluoroisobutyl Base, perfluoro-tert-butyl, 2,2,3,3,4,4,5,5-octafluoropentyl, perfluorohexyl, and the like.

The aliphatic cyclic hydrocarbon group having 4 to 20 carbon atoms and having at least one fluorine atom represented by R ^E is exemplified by, for example, monofluorocyclopentyl, difluorocyclopentyl, perfluorocyclopentyl, monofluorocyclohexyl, Difluorocyclopentyl, perfluorocyclohexylmethyl, fluoronorbornyl, fluoroadamantyl, fluoroborneyl, fluoroisobornyl, fluorotricyclodecyl, fluorotetracycline, and the like.

The monomer which obtains the above structural unit (Da) is exemplified by, for example, trifluoromethyl (meth)acrylate and 2,2,2-trifluoroethyl (meth)acrylate. Ester, 2,2,2-trifluoroethoxycarbonylmethyl (meth)acrylate, perfluoroethyl (meth)acrylate, perfluoro-n-propyl (meth)acrylate, perfluoro(meth)acrylate Isopropyl ester, perfluoro-n-butyl (meth)acrylate, perfluoroisobutyl (meth)acrylate, perfluorotributyl (meth)acrylate, 2-(1,1, 1,3,3,3-hexafluoropropyl)ester, 1-(2,2,3,3,4,4,5,5-octafluoropentyl) (meth)acrylate, (methyl) Perfluorocyclohexyl methyl acrylate, 1-(2,2,3,3,3-pentafluoropropyl) (meth)acrylate, monofluorocyclopentanyl (meth)acrylate, (meth)acrylic acid Fluorocyclopentyl ester, perfluorocyclopentyl (meth)acrylate, monofluorohexyl (meth)acrylate, difluorocyclopentyl (meth)acrylate, perfluorocyclohexylmethyl (meth)acrylate, Fluoric acid ethyl nordyl acrylate, fluoroadamantyl (meth) acrylate, flubornyl (meth) acrylate, fluoroisobornyl (meth) acrylate, fluorotricyclodecyl (meth) acrylate, ( Methyl) fluorotetracyclodecyl acrylate or the like.

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

The content ratio of the structural unit (Da) is preferably from 5 mol% to 95 mol%, more preferably from 10 mol% to 90 mol%, and more preferably relative to all structural units constituting the [D] polymer. It is 25% to 80% by mole. By becoming the content ratio, a higher dynamic contact angle of the surface of the resist film can be exhibited upon immersion exposure.

[structural unit (Db)]

The structural unit (Db) is a structural unit represented by the following formula (6b). Since the [D] polymer has a structural unit (Db) and thus has improved hydrophobicity, the dynamic contact angle of the surface of the resist film formed from 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 (s+1)-valent hydrocarbon group having 1 to 20 carbon atoms, 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 -CO-NH- constructor. R' is a hydrogen atom or a monovalent organic group. R ²² is a single bond, a divalent chain hydrocarbon group having 1 to 10 carbon atoms or a divalent aliphatic hydrocarbon group having 4 to 20 carbon atoms. 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 bond is bonded to the junction 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 may be the same or different.

When R ²³ is a hydrogen atom, it is preferred in terms of improving the solubility of the [D] polymer to an alkali developer.

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

The above structural unit (Db) is enumerated as, for example, the following formula (6b-1)~(6b-3) indicates the structural unit and so on.

In the above formulae (6b-1) to (6b-3), R ^21' is a divalent linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms. 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 may be the same or different.

The content ratio of the above structural unit (6b) is preferably from 0 mol% to 90 mol%, more preferably from 5 mol% to 85 mol%, more preferably all structural units constituting the [D] polymer. It is 10% by mole to 80% by mole. By setting the content ratio, the degree of reduction in the dynamic contact angle of the surface of the resist film formed from 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, equivalent to a structural unit ( Except for Db). By making the [D] polymer have a structural unit (Dc), the shape of the resulting resist pattern is made better. As for the structural unit (Dc) listed as the above [A] polymerization Construction unit (II), etc.

The content ratio of the above structural unit (Dc) is preferably from 5 mol% to 90 mol%, more preferably from 10 mol% to 80 mol%, more preferably all structural units constituting the [D] polymer. It is 15% by mole to 755% by mole. When the content ratio of the structural unit (Dc) is less than the above lower limit, the development defect in the resist pattern may not be sufficiently suppressed. When the content ratio of the structural unit (Dc) exceeds the above upper limit, the hydrophobicity of the surface of the obtained resist film may be lowered.

[Other construction units]

Further, the [D] polymer may have, for example, at least one structure selected from the group consisting of a structural unit containing an alkali-soluble group, a lactone structure, a cyclic carbonate structure, and a sultone structure, in addition to the above structural unit. Other structural units such as structural units and structural units containing alicyclic groups. The above alkali-soluble group is exemplified by, for example, a carboxyl group, a sulfonylamino group, a sulfo group or the like. 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 is exemplified by the 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, preferably 20 mol% or less, based on the total structural unit of 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 The amount is preferably from 0 to 20 parts by mass, more preferably from 0.5 part by mass to 15 parts by mass, even more preferably from 1 part by mass to 10 parts by mass per 100 parts by mass of the [A] polymer. When the content of the [D] polymer 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 of [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 agent as necessary.

The solvent [E] is exemplified by, for example, an alcohol solvent, an ether solvent, a ketone solvent, a guanamine solvent, an ester solvent, or a hydrocarbon solvent.

The alcohol solvent is exemplified by, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, second butanol, third butanol, n-pentanol, isoamyl alcohol, 2-methylbutyl Alcohol, second pentanol, third pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, second hexanol, 2-ethylbutanol, second heptanol, 3-glycol Alcohol, n-octanol, 2-ethylhexanol, second octanol, n-nonanol, 2,6-dimethyl-4-heptanol, n-nonanol, second-undecyl alcohol, trimethyl Sterol, second-tetradecyl alcohol, second heptadecyl alcohol, decyl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, Monoalcoholic solvent such as diacetone alcohol; ethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2 a polyol solvent such as 5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, 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, diethylene 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 monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, etc. An alcohol partial ether solvent or the like.

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

The ketone solvent is exemplified by, for example, acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, diethyl ketone, methyl isobutyl ketone, and 2-heptanone (methyl-n-pentyl ketone). a chain ketone solvent such as ethyl n-butyl ketone, methyl n-hexyl ketone, diisobutyl ketone or trimethyl fluorenone; cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methyl A cyclic ketone solvent such as cyclohexanone; 2,4-pentanedione, etidylacetone, acetophenone or the like.

The guanamine-based solvent is, for example, a cyclic amide-based solvent such as N,N'-dimethylimidazolidinone or N-methylpyrrolidone; N-methylformamide, N,N-dimethylmethyl Indoleamine, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methyl A chain amide-based solvent such as acrylamide.

The ester solvent is exemplified by, for example, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, second butyl acetate, n-amyl acetate, isoamyl acetate. , second amyl acetate, 3-methoxybutyl acetate, methyl amyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl acetate Acetate solvent such as cyclohexyl ester or n-decyl acetate; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diacetic acid diethyl diacetate Alcohol monoethyl ether ester, diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate a polyol partial ether acetate solvent such as dipropylene glycol monomethyl ether acetate or dipropylene glycol monoethyl ether acetate; a carbonate solvent such as dimethyl carbonate or diethyl carbonate; a glycol diacetate; Methoxy tris-diol acetate, ethyl propionate, n-butyl propionate, isoamyl propionate, diethyl oxalate, grass Di-n-butyl acid ester, methyl acetoxyacetate, ethyl acetoacetate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate Ester, diethyl phthalate, and the like.

The hydrocarbon solvent is exemplified by, for example, n-pentane, isopentane, n-hexane, isohexane, n-heptane, isoheptane, 2,2,4-trimethylpentane, n-octane, isooctane, and ring. An aliphatic hydrocarbon solvent such as hexane or methylcyclohexane; Benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, cumene, diethylbenzene, isobutylbenzene, triethylbenzene An aromatic hydrocarbon solvent such as diisopropylbenzene or n-pentylnaphthalene.

Among these, an ester solvent or a ketone solvent is preferred, and a polyol partial ether acetate solvent or a cyclic ketone solvent, and more preferably propylene glycol monomethyl ether acetate or cyclohexanone. . 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]. The other optional components mentioned above are, for example, a biasing accelerator, 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.

(biasing accelerator)

The biasing accelerator has an effect of more effectively segregating the [D] polymer on the surface of the resist film when the radiation sensitive linear resin composition contains the [D] polymer. By including the biasing accelerator in the radiation-sensitive resin composition, the amount of the [D] polymer added can be made smaller than in the past. According to this, the dissolution of the component self-resisting agent film toward the liquid immersion liquid can be further suppressed without damaging the basic characteristics of the resist such as LWR, development defect, and pattern collapse resistance, and the liquid immersion exposure can be performed at a higher speed by high-speed scanning. It can suppress defects from liquid immersion such as water mark defects and improve the hydrophobicity of the surface of the resist film. Can be used as the bias The user of the chemical accelerator may be a low molecular compound having a specific dielectric constant of 30 or more and 200 or less and a boiling point of 100 ° C or higher at 1 atm. Specific examples of the compound include a lactone compound, a cyclic carbonate compound, a nitrile compound, and a polyhydric alcohol.

Specific examples of the above lactone compound include, for example, γ-butyrolactone, valerolactone, mevalononitrile, norbornane lactone and the like.

Specific examples of the cyclic carbonate compound include, for example, propyl carbonate, ethyl carbonate, butyl carbonate, and vinyl carbonate.

Specific examples of the above nitrile compound are exemplified by succinonitrile and the like. The above polyol is exemplified by glycerin or the like.

As the biasing accelerator, these are preferably a lactone compound or a cyclic carbonate compound, more preferably a lactone compound, and more preferably γ-butyrolactone.

The content of the partialization accelerator is preferably from 10 parts by mass to 500 parts by mass, more preferably from 10 parts by mass to 300 parts by mass, even more preferably 100 parts by mass based on the total amount of the polymer in the radiation sensitive resin composition. It is 10 parts by mass to 150 parts by mass.

<Surfactant>

The surfactant has an effect of improving coatability, streaking property, developability, and the like. As the surfactant, for example, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octyl phenyl ether, polyoxyethylene n-decyl phenyl ether, poly Ethylene glycol dilaurate, polyethyl b Nonionic surfactants such as diol distearate; commercially available products are listed as KP341 (Shin-Etsu Chemical Co., Ltd.), POLYFLOW No. 75, POLYFLOW No. 95 (above is Kyoei Chemical Co., Ltd.), EF TOP EF301 EF TOP EF303, EF TOP EF352 (above TOHCHEM PRODUCTS), MEGAFAC F171, MEGAFAC F173 (above DIC), FLORARD FC430, FLORARD FC431 (above Sumitomo 3M), ASAHI GUARD AG710, SURFLON S-382, SURFLON SC-101, SURFLON SC-102, SURFLON SC-103, SURFLON SC-104, SURFLON SC-105, SURFLON 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 an alicyclic skeleton)

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

Examples of the compound having an alicyclic skeleton are, for example, adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and 1-adamantanecarboxylic acid tert-butyl ester; and tert-butyl deoxycholate; Deoxycholate such as tributoxycarbonyl methyl deoxycholate or 2-ethoxyethyl deoxycholate; tert-butyl lithochate, third butoxycarbonyl methyl lithate, lithocholic acid a stone cholate such as 2-ethoxyethyl ester; 3-[2-hydroxy-2,2-bis(trifluoromethyl)ethyl]tetracyclic [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 is an effect of increasing the amount of acid generated by the [B] acid generator, and exhibits an effect of improving the "apparent sensitivity" of the radiation-sensitive resin composition.

Sensitizers are listed, for example, as oxazoles, acetophenones, benzophenones, naphthalenes, phenols, diacetyl, eosin, rose, pyrenes, anthracenes, phenanthrene Thiazines and the like. These sensitizers may be used alone 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 obtained by, for example, mixing [A] polymer, [B] acid generator, optionally [C] acid diffusion controlling agent, [D] polymer, etc., and [E] in a specific ratio. Modulated with solvent. After the radiation-sensitive resin composition is mixed, it is preferably filtered by, for example, a filter having a pore diameter of about 0.05 μm. The solid 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, more preferably 1% by mass. The amount is %~20% by mass.

<Resist pattern formation method>

The method for forming the resist pattern has the steps of: forming a resist film by the radiation-sensitive resin composition (hereinafter also referred to as "resist film forming step"), and exposing the resist film (hereinafter) Also referred to as "exposure step"), and a step of developing the exposed resist film (hereinafter also referred to as "development step").

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

[Resistance film forming step]

This step forms a resist film using the radiation sensitive resin composition. As the substrate on which the resist film is formed, a conventional wafer such as a tantalum wafer, ruthenium dioxide, or aluminum-coated wafer can be used. Further, an organic or inorganic antireflection film can be formed on the substrate as disclosed in Japanese Laid-Open Patent Publication No. Hei. 6-12452 or JP-A-59-93448. The coating method is exemplified by, for example, spin coating, casting coating, roll coating, and the like. After coating, prebaking (PB) may also be carried out as needed 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 resist film is preferably from 10 nm to 1,000 nm, more preferably from 10 nm to 500 nm.

In the case of performing immersion exposure, in the case where the radiation-sensitive resin composition does not contain the water-repellent polymer additive, etc., in order to avoid direct contact between the liquid immersion liquid and the resist film, it may be provided on the resist film formed on the resist film. The insoluble liquid in the immersion liquid is immersed in a protective film. The protective film for liquid immersion is preferably used in a solvent-peelable protective film which can be removed by a solvent before the step (3) (see, for example, JP-A-2006-227632), and a developer-peelable type protective film which is peeled off simultaneously with development by a developing step. Any one of the films (see, for example, WO2005-069076, WO2006-035790, etc.). However, from the viewpoint of the amount of treatment, it is preferred to use a developer-peelable liquid immersion protective film.

[Exposure step]

In this step, the resist film formed in the resist film forming step is exposed to light by a radiation such as a mask or a liquid immersion medium such as water. The radiation used for exposure is determined by, for example, visible light rays, ultraviolet rays, far ultraviolet rays, X-rays, gamma rays, and the like, and charged particle beams such as electron beams and alpha rays. Among these, it is preferably far ultraviolet rays, electron beams, more preferably ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), electron beam, and more preferably ArF excimer laser light, electrons. bundle.

When the exposure is carried out by liquid immersion exposure, the liquid immersion liquid used is exemplified by, for example, water, a fluorine inert liquid or the like. The liquid immersion liquid is preferably for the exposure wavelength a liquid that is transparent and whose temperature coefficient of the optical image projected onto the film is limited to a minimum refractive index as small as possible, especially when the exposure light source is ArF excimer laser light (wavelength 193 nm), in addition to the above viewpoint, Water is preferably used from the viewpoint of easiness of handling and ease of handling. When water is used, an additive which reduces the surface tension of water and increases the interfacial activity can also be added in a small ratio. Preferably, the additive does not dissolve the resist film on the wafer and has negligible effects on the optical coating beneath the resist. The water used is preferably distilled water.

After the above exposure, post-exposure bake (PEB) is preferably performed to promote the [A] polymer or the like caused by the acid generated from the [B] acid generator in the exposed portion of the resist film. Dissociation of the acid dissociative group. According to the PEB, it is possible to reliably produce poor solubility of the exposed portion and the unexposed portion with respect to the developer. The PEB temperature is usually from 50 ° C to 180 ° C, preferably from 80 ° C to 130 ° C. The PEB time is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds.

[Development Step]

The developing step develops the resist film exposed in the above exposure step. Thereby, a specific resist pattern can be formed. After development, it is usually washed with a washing liquid such as water or alcohol, and dried.

The developing solution used for the above development is, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium citrate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, and di-negative in the case of alkali development. Propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanol Amine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo[5.4.0]-7-undecene, 1,5-diazabicyclo- [4.3.0] An alkaline aqueous solution obtained by dissolving at least one of a basic compound such as 5-nonene. Among these, an aqueous TMAH solution is preferred, and a 2.38 mass% aqueous solution of TMAH is more preferred.

In addition, in the case of developing an organic solvent, an organic solvent such as a hydrocarbon solvent, an ether solvent, an ester solvent, a ketone solvent, or an alcohol solvent, or a solvent containing an organic solvent may be mentioned. The above-mentioned organic solvent is, for example, one or two or more kinds of solvents exemplified as the [E] solvent of the radiation sensitive resin composition. Among these, an ester solvent or a ketone solvent is preferred. The ester solvent is preferably an acetate solvent, more preferably n-butyl acetate. The ketone solvent is preferably a chain ketone, more preferably 2-heptanone. The content of the organic solvent in the developer is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and most preferably 99% by mass or more. The components other than the organic solvent in the developer are exemplified by water, eucalyptus oil and the like.

The developing method is exemplified by a method of immersing a substrate in a tank filled with a developing solution for a certain period of time (dipping method), a method of filling the surface of the substrate with a surface tension and resting for a certain period of time (overfilling method), and spraying the developing solution on the developing solution. A method (distribution method) on the surface of the substrate, a method of applying a developing solution to the substrate by scanning the developing solution coating nozzle at a constant speed, and rotating at a constant speed (dynamic dispersion method).

<Sense Radiation Acid Generator>

The radiation-sensitive linear acid generator contains the compound (I).

The radiation-sensitive linear acid generator can increase the squareness of the LWR property, the MEEF property, and the cross-sectional shape of the radiation-sensitive resin composition containing the radiation. According to this, the radiation-sensitive acid generator can be suitably used as a component of the radiation-sensitive resin composition.

<compound>

This compound is the above compound (I).

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

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

[Examples]

The invention is specifically illustrated by the following examples, but the invention is not limited by the examples. Further, each of the measurement systems in the examples and the comparative examples was carried out by the following method.

^[1 H-NMR analysis, ¹³ C-NMR analysis and ¹⁹ F-NMR analysis]

The analysis was carried out using a nuclear magnetic resonance apparatus (JNM-EX400 of JEOL Ltd.) using ruthenium chloroform as a measurement solvent.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]

GPC column made of TOSOH (G2000HXL: 2, G3000HXL: 1 , G4000HXL: 1), flow rate: 1.0 mL/ Minutes, dissolution solvent: tetrahydrofuran, column temperature: 40 ° C analysis conditions, measured by monodisperse polystyrene as a standard gel permeation chromatography (GPC). Further, the degree of dispersion (Mw/Mn) was calculated from the measurement results of Mw and Mn.

<Synthesis of Compound (I)> [Example 1] (Synthesis of Compound (B-1)) (1) Synthesis of compound (S-b)

After the dried 300 mL three-neck reactor equipped with a dropping funnel was placed under an argon atmosphere, a solution of 8.91 g (51.4 mmol) of hexane cyclopentylmagnesium in 30 mL of hexane was added, and while stirring with a magnet mixer, a chloroform was added. 3.25 mL (25.7 mmol) of decane and 40 mL of tetrahydrofuran (THF) were stirred at 0 ° C for 30 minutes. Then, a solution of 7.41 g (25.7 mmol) of the compound represented by the following formula (S-a) in THF (30 mL) was added dropwise. After confirming the completion of the reaction by gas chromatography, an aqueous ammonium chloride solution was added and stirred for 1 hour, and then the reaction was stopped. The resulting liquid was filtered with diatomaceous earth to remove insolubles. Then, the mixture was extracted with ethyl acetate, and the aqueous layer and the organic layer were separated, and then the organic layer was washed with aqueous sodium hydrogen carbonate. The obtained organic layer was dried and concentrated under reduced pressure, and purified by recrystallization to give a compound (yield: 23%, purity: 99%).

(2) Synthesis of compound (S-c)

After the 200 mL pear-type reactor equipped with the condenser was placed under an argon atmosphere, 2.80 g (17.7 mmol) of sodium sulfite and 20 mL of water were added to the sulfonating agent, and the compound (Sb) 2.00 was added while stirring with a magnet stirrer. A solution of g (5.91 mmol) in 60 mL of methanol and 0.60 g (7.09 mmol) of sodium hydrogen carbonate was stirred at 60 ° C to 70 ° C for 2 hours. After confirming the completion of the reaction by ¹⁹ F-NMR, the mixture was extracted with dichloromethane, and the aqueous layer and organic layer were separated. The obtained organic layer was dried and concentrated under reduced pressure, and then purified by recrystallization to obtain 0.92 g (yield: 35%, purity: 99%) of the compound represented by the following formula (Sc) as a white solid.

(3) Synthesis of Compound (B-1)

After the 100 mL pear-shaped reactor was placed under an argon atmosphere, 0.62 g (2.07 mmol) of triphenylphosphonium chloride and 7 mL of water were fed, and the compound (Sc) obtained above was added while stirring with a magnetic stirrer. 2.07 mmol) of a 20 mL solution of dichloromethane was stirred at 20 ° C to 30 ° C for 2 hours. After confirming the completion of the reaction by ¹⁹ F-NMR, the mixture was extracted with dichloromethane, and the aqueous layer and organic layer were separated. The obtained organic layer was dried and concentrated under reduced pressure, and purified by recrystallization to obtain 1.2 g (yield: 85%, purity: 99%) of the compound represented by the following formula (B-1).

¹ H-NMR analysis (measurement solvent: chloroform, standard material: tetramethyl decane); δ=7.66-7.80 (m, 15H), 2.75-2.78 (t, 1H), 1.94-1.98 (m, 1H), 1.79-1.83(m,3H), 1.58-1.69(m,8H), 1.48-1.56(m,10H),1.33-1.43(m,2H),1.16-1.20(m,2H),0.88-0.92(m , 2H).

[Examples 2 to 17] (Synthesis of Compound (B-2) to (B-17))

The compound represented by the following formula (B-2) to (B-17) was obtained in the same manner as in Example 1.

¹ H-NMR analysis (measurement solvent: chloroform, reference material: tetramethyl decane) data is shown below.

Compound (B-2); δ=7.66-7.80 (m, 15H), 2.75-2.78 (t, 1H), 2.00-2.04 (m, 3H), 1.79-1.83 (m, 3H), 1.66-1.77 (m) , 12H), 1.48-1.59 (m, 9H), 1.33-1.43 (m, 2H), 1.14-1.21 (m, 3H), 0.90-0.94 (m, 2H).

Compound (B-3); δ=7.66-7.80 (m, 15H), 2.75-2.78 (t, 1H), 2.29-2.33 (m, 2H), 2.12-2.15 (m, 2H), 1.68-1.88 (m) , 8H), 1.59-1.63 (m, 5H), 1.47-1.50 (m, 3H), 1.26-1.33 (m, 5H), 0.81 - 0.84 (t, 3H).

Compound (B-4); δ=7.66-7.80 (m, 15H), 4.21-4.25 (m, 1H), 2.75-2.78 (t, 1H), 2.44-2.48 (m, 2H), 1.85-1.89 (m , 2H), 1.71-1.81 (m, 10H), 1.52-1.64 (m, 10H), 1.46-1.50 (m, 1H).

Compound (B-5); δ=7.66-7.80 (m, 15H), 3.89-3.93 (m, 1H), 2.75-2.78 (t, 1H), 1.78-1.82 (m, 4H), 1.55-1.62 (m , 10H), 1.47-1.54 (m, 7H).

Compound (B-6); δ=7.66-7.80 (m, 15H), 3.38-3.42 (t, 1H), 3.09-3.13 (m, 1H), 2.17-2.21 (m, 2H), 1.74-1.89 (m) , 12H), 1.48-1.62 (m, 9H), 1.36-1.40 (m, 2H).

Compound (B-7); δ=7.66-7.80 (m, 15H), 1.84-2.02 (m, 4H), 1.69-1.81 (m, 12H), 1.48-1.62 (m, 9H), 1.19-1.23 (t, 2H).

Compound (B-8); δ=7.66-7.80 (m, 15H), 4.21-4.25 (m, 1H), 3.96-4.00 (m, 1H), 2.75-2.78 (t, 1H), 2.33-2.48 (m) , 4H), 1.85-2.03 (m, 8H), 1.72-1.80 (m, 10H), 1.54-1.58 (m, 4H).

Compound (B-9); δ=7.66-7.80 (m, 15H), 4.21-4.25 (m, 1H), 3.83-3.87 (d, 2H), 3.18-3.22 (t, 1H), 2.77-2.81 (m) , 1H), 2.44 - 2.48 (m, 2H), 1.74-1.89 (m, 12H), 1.68-1.72 (m, 4H), 1.47-1.55 (m, 6H).

Compound (B-10); δ=7.66-7.80 (m, 15H), 1.98-2.02 (m, 1H), 1.56-1.61 (m, 8H), 1.51-1.55 (m, 8H), 1.41-1.49 (m , 2H).

Compound (B-11); δ=7.66-7.80 (m, 15H), 1.85-2.15 (m, 1H), 1.45-1.55 (m, 12H), 1.25-1.40 (m, 10H), 1.19-1.23 (m) , 2H).

Compound (B-12); δ=7.66-7.80 (m, 15H), 1.95-2.05 (m, 1H), 1.82-1.92 (m, 6H), 1.67-1.77 (m, 24H), 1.12-1.30 (m) , 6H).

Compound (B-13); δ=7.66-7.80 (m, 15H), 1.85-2.15 (m, 1H), 1.57-1.67 (m, 1H), 1.37-1.55 (m, 15H), 1.16-1.32 (m) , 8H), 0.88-0.94 (d, 6H).

Compound (B-14); δ = 7.66-7.80 (m, 15H), 3.50-3.70 (m, 4H), 1.85-2.15 (m, 1H), 1.55-1.74 (m, 7H), 1.29-1.51 (m, 7H), 1.18-1.24 (t, 2H).

Compound (B-15); δ=7.66-7.80 (m, 15H), 7.22-7.35 (m, 5H), 3.27-3.33 (m, 1H), 1.49-1.55 (m, 2H), 0.73-0.79 (t , 3H).

Compound (B-16); δ=7.66-7.80 (m, 15H), 3.54-3.60 (t, 1H), 2.34-2.54 (m, 4H), 1.90-2.09 (m, 5H), 1.41-1.65 (m) , 7H), 1.29-1.39 (m, 2H).

Compound (B-17); δ=7.66-7.80 (m, 15H), 3.18-3.24 (t, 1H), 2.31 (s, 6H), 1.85-2.15 (m, 1H), 1.74-1.80 (t, 2H) ), 1.29-1.65 (m, 9H).

<Synthesis of Polymer>

The compound (monomer) used for the synthesis of [A] polymer and [D] polymer is shown below.

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

21.12 g (55 mol%) of the above compound (M-1), 3.84 g (10 mol%) of the compound (M-3), and 13.44 g (35 mol%) of the compound (M-5) were dissolved in 80 g of In 2-butanone, AIBN 3.54 g of a monomer solution was then added. Next, a 200 mL three-necked flask having 40 g of 2-butanone was fed with nitrogen gas for 30 minutes, and then heated to 80 ° C with stirring, and the prepared monomer solution was added dropwise thereto over 3 hours with a dropping funnel. The polymerization reaction was carried out for 6 hours starting from the start of the dropwise addition as the start time of the polymerization reaction. Next, after completion of the polymerization reaction, the polymerization reaction liquid was cooled to 30 ° C or lower by water cooling. The cooled polymerization reaction liquid was poured into 800 g of methanol, and the precipitated white powder was filtered. After the filtered white powder was washed twice with 160 g of methanol, it was filtered and dried at 50 ° C for 17 hours to synthesize a white powdery polymer (A-1) (yield 29.18 g, yield 76%). The polymer (A-1) had a Mw of 4,500 and a Mw/Mn of 1.4. Further, as a result of ¹³ C-NMR analysis, the content ratios of the respective structural units derived from the compounds (M-1), (M-3), and (M-5) were 54 mol%, 11 mol%, and 35, respectively. Moer%.

[Synthesis Example 2] (Synthesis of Polymer (A-2))

The polymer (A-2) was synthesized in the same manner as in Synthesis Example 1 except that the monomer of the type and amount used in the following Table 1 was used. The total mass of the monomers used was the same as in Synthesis Example 1. The yield, Mw and Mw/Mn of the obtained polymer (A-2) are shown in Table 1.

[[D] Synthesis of Polymers] [Synthesis Example 3] (Synthesis of Polymer (D-1))

14.3 g (30 mol%) of the above compound (M-4) and 45.7 g (70 mol%) of the compound (M-6) were dissolved in 60 g of 2-butanone, and further, AIGN 3 g of a monomer solution was added. The 300 mL three-necked flask having 30 g of 2-butanone was fed with nitrogen gas for 30 minutes, and then heated to 80 ° C while stirring the reactor, and the above monomer solution was added dropwise over 3 hours using a dropping funnel. The polymerization reaction was carried out for 6 hours starting from the start of the dropwise addition as the start time of the polymerization reaction. After completion of the polymerization reaction, the polymerization reaction liquid was cooled to 30 ° C or lower with water cooling, and poured into a mixed liquid of 600 g of methanol:water (8:2 (mass ratio)) to precipitate a polymer. After removing the supernatant solution, 120 g of methanol was added to the precipitated polymer to wash the polymer. After removing the supernatant, it was dried at 50 ° C for 17 hours to synthesize the polymer (D-1). The polymer (D-1) had Mw of 4,200 and Mw/Mn of 1.3. Further, as a result of ¹³ C-NMR analysis, the content of fluorine atoms was 5% by mass, and the content ratios of structural units derived from (M-4) and (M-6) were 32.0 mol% and 68.0 mol%, respectively. .

<Modulation of Radiation-Linear Resin Composition>

The [B] acid generator, [C] acid diffusion control agent, [E] solvent, and [F] biasing accelerator used in the preparation of the radiation sensitive resin composition are shown below.

[[B]acid generator]

[B]acid generator used in the examples: the above synthesized compound (B-1) to (B-17)

The acid generator used in the comparative example: a compound represented by the following formulas (b-1) to (b-3)

[[C] Acid Diffusion Control Agent]

[[E]solvent]

E-1: propylene glycol monomethyl ether acetate

E-2: cyclohexanone

[[F] partialization accelerator]

F-1: γ-butyrolactone

[Embodiment 18]

100 parts by mass of (A-1) as the [A] polymer, (B-1) 15 parts by mass of the [B] acid generator, and (C-1) 1.1 mass as the [C] acid diffusion controlling agent , as part of [D] polymer (D-1), 7 parts by mass, (E-1) 2,590 parts by mass as (E) solvent, (E-2) 1,110 parts by mass, and as [F] partialization promotion The mixture (F-1) (15 parts by mass) was filtered through a filter having a pore diameter of 0.20 μm to prepare a radiation sensitive resin composition (J-1).

[Examples 19 to 56 and Comparative Examples 1 to 3]

The radiation-sensitive linear resin compositions (J-2) to (J-39) and (CJ-1) were prepared in the same manner as in Example 18 except that the components of the types and contents shown in Table 2 below were used. (CJ-3).

<Formation of resist pattern>

An antireflection film having a thickness of 105 nm was formed on the surface of a 12-inch wafer by using an antireflection film-forming composition ("ARC66" manufactured by Nissan Chemical Industries, Ltd.). The radiation-sensitive resin composition prepared above was applied onto the anti-reflection film, and subjected to SB at 45 ° C for 45 seconds to form a resist film having a film thickness of 95 nm. Next, the resist film was formed using an ArF excimer laser immersion exposure apparatus ("NSR S610C" by NIKON Corporation) at a ratio of NA = 1.3, ratio = 0.800, and Annular, through a 40 nm line and 80 nm. The mask pattern is exposed. After exposure, PEB was performed at 100 ° C for 45 seconds. Subsequently, development was carried out using a 2.38 mass% aqueous solution of TMAH, washed with water and dried to form a positive resist pattern of line and space. When the resist pattern is formed, a line width formed by a one-to-one line and a space mask having a target size of 40 nm is formed as a line-width of 40 nm line-to-one line and interval exposure amount as an optimum exposure amount. . Further, the measurement of the resist pattern was carried out using a scanning electron microscope ("CG4000" of Hitachi High-Tech Co., Ltd.).

<evaluation>

With respect to each of the radiation-sensitive resin compositions prepared as described above, the squareness of the sensitivity, the LWR performance, the MEEF performance, and the cross-sectional shape of the resist pattern were evaluated according to the following method. The evaluation results are shown in Table 3.

[Sensitivity]

The optimum exposure amount obtained above was taken as the sensitivity. When the sensitivity is 50 mJ/cm ² or less, it can be evaluated as "A (good)", and when it exceeds 50 mJ/cm ² , it is evaluated as "B (bad)".

[LWR performance]

Using the scanning electron microscope described above, the resist pattern formed as described above was observed from the upper portion of the pattern, and a line width of 50 points was measured at any point, and a value of three times the standard deviation was calculated from the distribution of the measured values, and The calculated value is taken as the LWR performance (nm). When the LWR performance is 5.5 nm or less, it can be evaluated as "A (good)", and when it exceeds 5.5 nm, it is evaluated as "B (bad)".

[MEEF performance]

Using the above scanning electron microscope, at the above optimum exposure amount, five mask sizes (48.0 nm line/100 nm interval, 49.0 nm line/100 nm interval, 50.0 nm line/100 nm interval, 51.0 nm line/100 nm interval, 52.0) The nm line/100 nm interval is resolved, and the line width of the resist pattern is determined. The horizontal axis is set as the mask size, and the vertical axis is set to the line width formed by each mask size. The obtained measured values are plotted, and the slope of the approximate straight line is obtained by the least square method, and the slope is used as the MEEF performance. The MEEF performance is such that the closer the value is to 1, the better the display. When the MEEF performance was 4.7 or less, it was evaluated as "A (good)", and when it was more than 4.7, it was evaluated as "B (bad)".

[Rectangularity of section shape]

Using the scanning electron microscope described above, the resist pattern was observed, and the line width x of the upper portion of the pattern and the line width y of the lower portion of the pattern were measured, and the ratio x/y was calculated. The x/y value was measured at 10 points in any point of the resist pattern, and the sum average value ([x/y]) of these values was obtained as an index of the rectangular shape of the cross-sectional shape. The squareness of the cross-sectional shape was evaluated as "A (good)" at 0.9 ≦ [x/y] ≦ 1.1, and "B (bad) when [x/y] < 0.9 or 1.1 < [x/y]. .

As understood from the results of Table 3, according to the radiation-sensitive resin composition composition of the examples, the RWR properties, the MEEF properties, and the cross-sectional shape were all rectangular, whereas the radiation-sensitive resin composition of the comparative example was used. The RWR performance, MEEF performance, and cross-sectional shape are not square.

[Industrial availability]

According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, it is possible to form a resist pattern which exhibits excellent MEEF performance and which has a small LWR and a rectangular shape in a cross-sectional shape. The radiation-sensitive acid generator of the present invention can be preferably used as a component of the radiation-sensitive resin composition. The compound of the present invention can be suitably used as the radiation-sensitive acid generator. Accordingly, these can be preferably used in the patterning of the lithography steps of various electronic devices such as semiconductor devices and liquid crystal devices.

Claims (13)

A radiation-sensitive resin composition containing a polymer having a structural unit containing an acid-dissociable group, and a radiation-sensitive acid generator, wherein the radiation-sensitive acid generator contains a compound represented by the following formula (1) : (In the formula (1), R ¹ and R ^{2 are} each independently a monovalent organic group having 1 to 20 carbon atoms, and R ³ , R ⁴ and R ^{5 are} each independently a hydrogen atom or a carbon number of 1 to 20; The organic group, R ¹ to R ^{5 ,} may also represent a part of the ring structure of carbon number 1 to 20 which is composed of two or more of these bonds and the carbon atoms to be bonded together, and n is 1 to 4 Integer, M ⁺ is a monovalent radiation-decomposable ruthenium cation). The radiation-sensitive resin composition of claim 1, wherein at least one of R ¹ and R ^{2 in} the above formula (1) is a group having a cyclic structure. The radiation sensitive resin composition of claim 1, wherein the above n is 1. A radiation-sensitive resin composition according to claim 1, wherein the above R ⁵ is a hydrogen atom. A radiation-sensitive resin composition according to claim 1, wherein the above R ³ and R ⁴ are a hydrogen atom. The radiation sensitive resin composition of claim 1, wherein the above R ² is a hydrocarbon group. The radiation sensitive resin composition of claim 1, wherein the above R ¹ is a hydrocarbon group. The radiation-sensitive resin composition of claim 1, wherein any one of R ¹ and R ^{2 in} the above formula (1) is a group having a cyclic structure. The radiation-sensitive resin composition of claim 1, wherein the radiation-decomposable phosphonium cation of the above M ⁺ is a phosphonium cation or a phosphonium cation. The radiation-sensitive resin composition of claim 1, wherein the structural unit containing the acid-dissociable group is represented by the following formula (2): (In the formula (2), R ⁶ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, and R ⁷ is a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic ring having 3 to 20 carbon atoms. The hydrocarbon group, R ⁸ and R ^{9 are} each independently a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or means that the groups are bonded to each other and bonded thereto. The carbon atom is composed of a carbon ring structure of 3 to 20 carbon atoms. A method for forming a resist pattern having the following steps: a step of forming a resist film, a step of exposing the resist film and a step of developing the exposed resist film, and the resist film is formed of the radiation sensitive resin composition of claim 1. A radiation sensitive acid generator containing a compound represented by the following formula (1): (In the formula (1), R ¹ and R ^{2 are} each independently a monovalent organic group having 1 to 20 carbon atoms, and R ³ , R ⁴ and R ^{5 are} each independently a hydrogen atom or a carbon number of 1 to 20; The organic group, R ¹ to R ^{5 ,} may also represent a part of the ring structure of carbon number 1 to 20 which is composed of two or more of these bonds and the carbon atoms to be bonded together, and n is 1 to 4 Integer, M ⁺ is a monovalent radiation-decomposable ruthenium cation). A compound represented by the following formula (1): (In the formula (1), R ¹ and R ^{2 are} each independently a monovalent organic group having 1 to 20 carbon atoms, and R ³ , R ⁴ and R ^{5 are} each independently a hydrogen atom or a carbon number of 1 to 20; The organic group, R ¹ to R ^{5 ,} may also represent a part of the ring structure of carbon number 1 to 20 which is composed of two or more of these bonds and the carbon atoms to be bonded together, and n is 1 to 4 Integer, M ⁺ is a monovalent radiation-decomposable ruthenium cation).