JP6743618B2 - Radiation-sensitive resin composition, method for forming resist pattern, radiation-sensitive acid generator, compound and method for producing compound - Google Patents

Description

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

With the miniaturization of various electronic device structures such as semiconductor devices and liquid crystal devices, further miniaturization of resist patterns in the lithography process is required, and therefore various radiation-sensitive resin compositions have been studied. A resist film formed from such a radiation-sensitive resin composition produces an acid in the exposed portion by irradiation with exposure light such as deep ultraviolet rays such as ArF excimer laser, extreme ultraviolet rays (EUV), and electron beam. Due to the catalytic action of, a difference in dissolution rate with respect to the developing solution occurs between the exposed portion and the unexposed portion, so that a resist pattern can be formed on the substrate.

Such a radiation-sensitive resin composition has not only excellent resolution but also LWR (Line Width Roughness) performance when forming a line-and-space pattern and a rectangular cross-sectional shape of a resist pattern to be formed. In addition to being excellent, the focal depth and the MEEF (Mask Error Enhancement Factor) performance are excellent, and it is required to obtain a highly accurate pattern with a high yield. To meet this demand, various structures of polymers contained in the radiation-sensitive resin composition have been studied. For example, by using a polymer having a lactone structure such as a butyrolactone structure or a norbornane lactone structure, a resist pattern can be obtained. It is known that the above-mentioned various performances can be improved while improving the adhesion to the substrate (see JP-A-11-212265, JP-A-2003-5375 and JP-A-2008-83370).

However, at the present time when the miniaturization of resist patterns is progressing to a level of 45 nm or less in line width, the required level of the above performance is further increased, and the conventional radiation-sensitive resin composition satisfies the above requirements. I can't do that. Further, recently, it is also required to suppress the shrinkage of the resist film during post-exposure heating (Post Exposure Bake (PEB)).

JP, 11-212265, A JP, 2003-5375, A JP, 2008-83370, A

The present invention has been made based on the above circumstances, and an object thereof is a radiation-sensitive resin excellent in LWR performance, resolution, rectangularity of cross-sectional shape, depth of focus, MEEF performance, and film shrinkage suppression property. It is to provide a composition and a method for forming a resist pattern.

The invention made to solve the above problems is a polymer having a structural unit containing an acid-labile group (hereinafter, also referred to as “structural unit (I)”) (hereinafter, also referred to as “[A] polymer”). And a radiation-sensitive acid generator (hereinafter, also referred to as “[B] acid generator”), wherein the radiation-sensitive acid generator is —SO ₃ ^— , a first carbon atom, a second A monovalent anion containing a carbon atom and two or more electron-withdrawing groups (excluding a fluorine atom, a fluoroalkyl group, —SO ₃ ^— and a sulfo group), and a monovalent radiation-sensitive onium cation. A first compound (hereinafter, also referred to as “compound (Z)”) having the —SO ₃ ^— and the second carbon atom bonded to the first carbon atom, and the first carbon atom and the second carbon. The radiation-sensitive resin composition has a total of two or more electron-withdrawing groups bonded to one or both of the atoms.

Another invention made to solve the above problems is a step of coating the radiation-sensitive resin composition described above on one surface side of a substrate, and a step of exposing the resist film obtained by the coating step. And a step of developing the exposed resist film, the method for forming a resist pattern.

（式（Ａ）中、Ｘは、それぞれ独立して、水素原子又はシアノ基である。ｎは、０又は１である。＊は、上記電子求引性基以外の部分との結合部位を示す。） Yet another invention made to solve the above-mentioned problems is —SO ₃ ^— , a first carbon atom, a second carbon atom, and two or more electron withdrawing properties represented by the following formula (A). Group and a monovalent anion containing an organic group other than the electron-withdrawing group, and a monovalent radiation-sensitive onium cation, wherein the first carbon atom contains the —SO ₃ ^— and the second carbon. A radiation-sensitive acid generator comprising a compound in which an atom is bonded, and the organic group and a total of two or more electron withdrawing groups are bonded to one or both of the first carbon atom and the second carbon atom. Is.

(In the formula (A), X is each independently a hydrogen atom or a cyano group. n is 0 or 1. * represents a binding site to a moiety other than the electron-withdrawing group. .)

（式（Ａ）中、Ｘは、それぞれ独立して、水素原子又はシアノ基である。ｎは、０又は１である。＊は、上記電子求引性基以外の部分との結合部位を示す。） Yet another invention made to solve the above-mentioned problems is —SO ₃ ^— , a first carbon atom, a second carbon atom, and two or more electron withdrawing properties represented by the following formula (A). Group and a monovalent anion containing an organic group other than the electron-withdrawing group, and a monovalent radiation-sensitive onium cation, wherein the first carbon atom contains the —SO ₃ ^— and the second carbon. A compound in which atoms are bonded and the organic group and a total of two or more electron withdrawing groups are bonded to one or both of the first carbon atom and the second carbon atom.

(In the formula (A), X is each independently a hydrogen atom or a cyano group. n is 0 or 1. * represents a binding site to a moiety other than the electron-withdrawing group. .)

（式（Ａ）中、Ｘは、それぞれ独立して、水素原子又はシアノ基である。ｎは、０又は１である。＊は、上記電子求引性基以外の部分との結合部位を示す。） Yet another invention made to solve the above-mentioned problems is —SO ₃ ^— , a first carbon atom, a second carbon atom, and two or more electron withdrawing properties represented by the following formula (A). Group and a monovalent anion containing an organic group other than the electron-withdrawing group, and a monovalent radiation-sensitive onium cation, wherein the first carbon atom contains the —SO ₃ ^— and the second carbon. A method for producing a compound in which an atom is bonded, and the organic group and a total of two or more electron withdrawing groups are bonded to one or both of the first carbon atom and the second carbon atom, wherein ethylene is used. Of an unsaturated compound having a pair of carbon atoms forming a reactive carbon-carbon double bond, the organic group bonded to one or both of the pair of carbon atoms, and a total of two or more electron withdrawing groups The method is characterized by comprising a step of adding sulfite to the double bond.

(In the formula (A), X is each independently a hydrogen atom or a cyano group. n is 0 or 1. * represents a binding site to a moiety other than the electron-withdrawing group. .)

（式（Ａ）中、Ｘは、それぞれ独立して、水素原子又はシアノ基である。ｎは、０又は１である。＊は、上記電子求引性基以外の部分との結合部位を示す。） Yet another invention made to solve the above-mentioned problems is —SO ₃ ^— , a first carbon atom, a second carbon atom, and two or more electron withdrawing properties represented by the following formula (A). Group and a monovalent anion containing an organic group other than the electron-withdrawing group, and a monovalent radiation-sensitive onium cation, wherein the first carbon atom contains the —SO ₃ ^— and the second carbon. A method for producing a compound in which an atom is bonded, and the organic group and a total of two or more electron withdrawing groups are bonded to one or both of the first carbon atom and the second carbon atom, wherein the halogen is An atom, a third carbon atom, a fourth carbon atom, two or more electron withdrawing groups, and the organic group, wherein the third carbon atom is the halogen atom and the fourth carbon atom. And the third carbon atom and halogen of the halogen compound in which the organic group and a total of two or more electron withdrawing groups are bonded to one or both of the third carbon atom and the fourth carbon atom. It is characterized by comprising a step of subjecting the atom to a substitution reaction with dithionite.

(In the formula (A), X is each independently a hydrogen atom or a cyano group. n is 0 or 1. * represents a binding site to a moiety other than the electron-withdrawing group. .)

According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, while exhibiting excellent depth of focus, MEEF performance and film shrinkage suppression property, LWR performance, resolution, rectangularity of cross-sectional shape, depth of focus. A resist pattern having excellent MEEF performance and film shrinkage suppression property can be formed. The radiation-sensitive acid generator and compound of the present invention can be suitably used as a component of a radiation-sensitive resin composition. According to the method for producing a compound of the present invention, the above compound can be easily and surely obtained. Therefore, these can be preferably used for manufacturing semiconductor devices, which are expected to be further miniaturized in the future.

<Radiation-sensitive resin composition>
The radiation sensitive resin composition contains a [A] polymer and a [B] acid generator. The radiation-sensitive resin composition has, as suitable components, a polymer having a larger mass content of fluorine atoms than [B'] other acid generators, [C] acid diffusion controller, and [A] polymer (hereinafter referred to as "polymer"). , "[D] polymer"), and/or [E] solvent may be contained, and other optional components may be contained as long as the effects of the present invention are not impaired. Hereinafter, each component will be described.

<[A] polymer>
The polymer [A] is a polymer having a structural unit (I) containing an acid dissociable group. Here, the “acid-dissociable group” refers to a group that substitutes a hydrogen atom such as a carboxy group or a hydroxy group and dissociates by the action of an acid. The polymer [A] may further have a structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure or a combination thereof (hereinafter, also referred to as “structural unit (II)”) in addition to the structural unit (I). Preferably, it may have another structural unit other than the structural units (I) to (II). The polymer [A] may have one type or two or more types of the above structural units, respectively. Hereinafter, each structural unit will be described.

[Structural unit (I)]
The structural unit (I) is a structural unit containing an acid dissociable group. In the exposed portion of the resist film formed of the radiation-sensitive resin composition, the acid-dissociable group of the structural unit (I) is dissociated by the acid generated by the irradiation of the radiation from the [B] acid generator or the like, As a result, there is a difference in solubility in the developing solution between the exposed portion and the unexposed portion of the resist film. As a result, it becomes possible to form a resist pattern from the resist film.

The structural unit (I) is not particularly limited, but for example, a structural unit represented by the following formula (2) (hereinafter, also referred to as “structural unit (I-1)”), a structural unit containing an acetal structure (hereinafter, "Structural unit (I-2)") and the like. The polymer [A] may have one type or two or more types of the structural units (I-1) and (I-2), respectively. The polymer [A] may have both the structural unit (I-1) and the structural unit (I-2). Hereinafter, the structural unit (I-1) and the structural unit (I-2) will be described.

(Structural unit (I-1))
The structural unit (I-1) is a structural unit represented by the following formula (2). A group represented by ^-CR 15 ^R 16 ^{R 17} in formula (2) is an acid-dissociable group.

In the above formula (2), R ¹⁴ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹⁵ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ¹⁶ and R ¹⁷ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or 3 to 3 carbon atoms which are combined with each other and are bonded to the carbon atom to which they are bonded. It represents an alicyclic structure of 20.

Here, the “hydrocarbon group” includes a chain hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group. This "hydrocarbon group" may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The “chain hydrocarbon group” refers to a hydrocarbon group that does not include a cyclic structure and is composed of only a chain structure, and includes both a linear hydrocarbon group and a branched hydrocarbon group. "Alicyclic hydrocarbon group" means a hydrocarbon group that contains only an alicyclic structure as a ring structure and does not contain an aromatic ring structure, and includes a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic group. Includes both hydrocarbon groups. However, it does not need to be composed of only an alicyclic structure, and a part thereof may include a chain structure. The “aromatic hydrocarbon group” refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it does not need to be composed only of an aromatic ring structure, and a part thereof may include a chain structure or an alicyclic structure.

As R ¹⁴ , a hydrogen atom and a methyl group are preferable, and a methyl group is more preferable, from the viewpoint of the copolymerizability of the monomer giving the structural unit (I-1).

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ¹⁵ , R ¹⁶ and R ¹⁷ include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms and a monovalent hydrocarbon group having 3 to 20 carbon atoms. Examples thereof include a valent alicyclic hydrocarbon group and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

Examples of the monovalent chain hydrocarbon group include alkyl groups such as methyl group, ethyl group, n-propyl group and i-propyl group;
Alkenyl groups such as ethenyl group, propenyl group, butenyl group;
Examples thereof include alkynyl groups such as ethynyl group, propynyl group and butynyl group.

Examples of the monovalent alicyclic hydrocarbon group include monovalent monocyclic alicyclic saturated hydrocarbon groups such as cyclopentyl group and cyclohexyl group;
A monovalent monocyclic alicyclic unsaturated hydrocarbon group such as a cyclopentenyl group or a cyclohexenyl group;
A monovalent polycyclic alicyclic saturated hydrocarbon group such as a norbornyl group, an adamantyl group, a tricyclodecyl group, a tetracyclododecyl group;
Examples thereof include monovalent polycyclic alicyclic unsaturated hydrocarbon groups such as norbornenyl group and tricyclodecenyl group.

Examples of the monovalent aromatic hydrocarbon group include aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group, anthryl group and fluorenyl group;
Examples thereof include aralkyl groups such as benzyl group, phenethyl group, naphthylmethyl group and anthrylmethyl group.

Examples of the alicyclic structure having 3 to 20 carbon atoms in which the groups of R ¹⁶ and R ¹⁷ are combined with each other and are bonded to each other include, for example, cyclopropane structure, cyclobutane structure, cyclopentane structure, cyclohexane structure, cycloheptane. A monocyclic alicyclic saturated hydrocarbon structure such as a structure, a cyclooctane structure, or a cyclodecane structure;
A polycyclic alicyclic saturated hydrocarbon structure such as a norbornane structure, an adamantane structure, a tricyclodecane structure, or a tetracyclododecane structure;
A monocyclic alicyclic unsaturated hydrocarbon structure such as cyclopropene structure, cyclobutene structure, cyclopentene structure, cyclohexene structure, cycloheptene structure, cyclooctene structure;
Examples thereof include polycyclic alicyclic unsaturated hydrocarbon structures such as norbornene structure and tricyclodecene structure.

Examples of the structural unit (I-1) include structural units represented by the following formula.

In the above formula, R ¹⁴ has the same meaning as in the above formula (2).

As the structural unit (I-1), structural units represented by the following formulas (2-1) to (2-5) (hereinafter, “structural units (I-1-1) to (I-1-5)”). Also referred to as “”.

In formulas (2-1) to (2-5) above, R ^{14 to} R ¹⁷ have the same meanings as in formula (2) above. i and j are each independently an integer of 1 to 4.

As the structural unit (I-1), the structural unit (I-1-1) is more preferable, and the structural unit derived from 1-alkyl-1-cyclopentyl(meth)acrylate and 2-alkyl-2-tetracyclododecyl( Structural units derived from (meth)acrylate are more preferred.

(Structural unit (I-2))
The structural unit (I-2) is a structural unit containing an acetal structure. Examples of the structural unit (I-2) include a structural unit containing a group represented by the following formula (X) (hereinafter, also referred to as “group (X)”) and the like. The group (X) decomposes by the action of an acid to produce *-R ^w OH, R ^X R ^Y ═O and R ^Z OH. In the group (X), —C(R ^X )(R ^Y )(OR ^Z ) is an acid dissociable group.

In the above formula (X), R ^X and R ^Y are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ^Z is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ^W is a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms. Two or more of R ^X , R ^Y , R ^Z, and R ^W may be combined with each other to form a ring structure having 3 to 20 ring members together with a carbon atom or an atom chain to which they are bonded. * Indicates a binding site to a portion other than the group (X) in the structural unit (I-2).

Here, the “number of ring members” refers to the number of atoms constituting a ring of an alicyclic structure, an aromatic ring structure, an aliphatic heterocyclic structure and an aromatic heterocyclic structure, and in the case of a polycycle, constitutes this polycycle. Refers to the number of atoms.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^X , R ^Y and R ^Z include, for example, 1 to 20 carbon atoms exemplified as R ¹⁵ , R ¹⁶ and R ^{17 in the} above formula (2). The same groups as the monovalent hydrocarbon group of 1. Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^W include a group obtained by removing one hydrogen atom from the above monovalent hydrocarbon group.

As R ^X and R ^Y , a hydrogen atom and a monovalent chain hydrocarbon group are preferable, a hydrogen atom and an alkyl group are more preferable, and a hydrogen atom and a methyl group are further preferable. R ^Z is preferably a monovalent chain hydrocarbon group and a monovalent alicyclic hydrocarbon group, more preferably an alkyl group and a monovalent polycyclic alicyclic saturated hydrocarbon group, a methyl group and a tetra group. The cyclododecyl group is particularly preferred.

As R ^W , a single bond and a divalent chain hydrocarbon group are preferable, a single bond and an alkanediyl group are more preferable, and a single bond and a methanediyl group are further preferable.

The ring structure having 3 to 20 ring members formed by two or more of R ^X , R ^Y , R ^Z and R ^W is, for example, 1,3-dioxacyclopentane structure or the like. An alkane structure etc. are mentioned.

The group (X) is preferably a group in which R ^W is a single bond, one of R ^X and R ^Y is a hydrogen atom, the other is a methyl group, and R ^Z is a tetracyclododecyl group.

Examples of the structural unit (I-2) include structural units represented by the following formula (3).

In the above formula (3), R ^C is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. L ¹ is a single bond or a divalent organic group having 1 to 20 carbon atoms. T is the above group (X). n is an integer of 1 to 3. When n is 2 or more, plural Ts may be the same or different.

From the viewpoint of the copolymerizability of the monomer giving the structural unit (I-2), R ^C is more preferably a hydrogen atom or a methyl group, and even more preferably a methyl group.

Examples of the divalent organic group having 1 to 20 carbon atoms represented by L ¹ include a substituted or unsubstituted divalent hydrocarbon group having 1 to 10 carbon atoms, —CO— and the like. Examples of the substituent of the hydrocarbon group include a hydroxy group, a halogen atom, an alkoxy group, a cyano group and the like.

As L ¹ , a single bond and —CO— are preferable, and —CO— is more preferable.

As n, 1 and 2 are preferable and 1 is more preferable.

The structural unit (I-2) is a structural unit represented by the above formula (3), L ¹ is —CO—, n is 1, R ^W in T is a single bond, and R is It is preferable that one of ^X and R ^Y is a hydrogen atom, the other is a methyl group, and R ^Z is a tetracyclododecyl group.

The lower limit of the content of the structural unit (I) is preferably 10 mol%, more preferably 25 mol%, and even more preferably 40 mol% with respect to the total structural units constituting the [A] polymer. On the other hand, the upper limit of the content ratio is preferably 80 mol%, more preferably 70 mol%, further preferably 60 mol%. By setting the content ratio of the structural unit (I) in the above range, the sensitivity and the like of the radiation-sensitive resin composition is further improved, and as a result, LWR performance, resolution, rectangularity of cross-sectional shape, depth of focus, The MEEF performance and the film shrinkage suppression property can be further improved.

[Structural unit (II)]
The structural unit (II) is a structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof (excluding those corresponding to the structural unit (I)). When the polymer [A] further has the structural unit (II), the solubility in a developing solution can be adjusted to a more appropriate level, and as a result, the LWR performance of the radiation-sensitive resin composition, It is possible to further improve the resolution, the rectangularity of the cross-sectional shape, the depth of focus, the MEEF performance, and the film shrinkage suppression property. Moreover, the adhesiveness between the resist film formed from the radiation sensitive resin composition and the substrate can be further improved. Here, the lactone structure refers to a structure having one ring (lactone ring) containing a group represented by -OC(O)-. In addition, the cyclic carbonate structure refers to a structure having one ring (cyclic carbonate ring) containing a group represented by —O—C(O)—O—. Further, the sultone structure refers to a structure having one ring (sultone ring) containing a group represented by -OS(O) _2- . Examples of the structural unit (II) include structural units represented by the formulas below.

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

Of these, the structural unit (III) is preferably a structural unit containing a norbornane lactone structure, a structural unit containing a γ-butyrolactone structure, a structural unit containing an ethylene carbonate structure, and a structural unit containing a norbornane sultone structure.

When the polymer [A] has the structural unit (II), the lower limit of the content ratio of the structural unit (II) with respect to all the structural units constituting the polymer [A] is preferably 1 mol% and 10 mol%. More preferably, 30 mol% is still more preferable, and 40 mol% is particularly preferable. On the other hand, the upper limit of the content ratio is preferably 80 mol%, more preferably 70 mol%, further preferably 60 mol%. By setting the above content ratio within the above range, it is possible to further improve the adhesiveness between the resist film formed from the radiation sensitive resin composition and the substrate. When the content ratio is less than the lower limit, the adhesiveness between the resist film formed from the radiation sensitive resin composition and the substrate may decrease. On the contrary, when the content ratio exceeds the upper limit, the pattern formability of the radiation-sensitive resin composition may decrease.

[Other structural units]
The polymer [A] may have a structural unit other than the structural units (I) to (II). Examples of other structural units include structural units containing a hydroxy group. Examples of the hydroxy group include alcoholic hydroxyl group and phenolic hydroxyl group. When the polymer [A] has a structural unit containing a phenolic hydroxyl group, the sensitivity in KrF exposure, EUV exposure, electron beam exposure and the like can be further improved.

Examples of the structural unit containing a hydroxy group include structural units represented by the following formula.

In the above formula, R ^L2 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

As the structural unit containing a hydroxy group, a structural unit derived from hydroxystyrene and a structural unit derived from 3-hydroxyadamantyl (meth)acrylate are preferable.

When the polymer [A] has a structural unit containing a hydroxy group, the lower limit of the content of the structural unit containing a hydroxy group is preferably 1 mol% based on all structural units constituting the polymer [A]. , 15 mol% is more preferable, and 30 mol% is further preferable. On the other hand, the upper limit of the content ratio is preferably 80 mol%, more preferably 70 mol%, further preferably 60 mol%.

The polymer [A] may have a structural unit other than the structural unit containing a hydroxy group as another structural unit. Examples of such other structural unit include a structural unit containing a carboxy group, a cyano group, a nitro group, a sulfonamide group, a combination thereof, a structural unit containing a non-dissociative hydrocarbon group, and the like. The upper limit of the content of these structural units is preferably 20 mol% and more preferably 10 mol% with respect to all structural units constituting the polymer [A].

The lower limit of the content of the [A] polymer with respect to all the polymers contained in the radiation-sensitive resin composition is preferably 60% by mass, more preferably 70% by mass, and further preferably 90% by mass. By setting the content to the above lower limit or more, it is possible to further improve the LWR performance, the resolution, the rectangularity of the cross-sectional shape, the depth of focus, the MEEF performance, and the film shrinkage suppression property of the radiation-sensitive resin composition. ..

The lower limit of the content of the polymer [A] is preferably 70% by mass, more preferably 80% by mass, and even more preferably 85% by mass based on the total solid content of the radiation-sensitive resin composition. On the other hand, the upper limit of the content of the [A] polymer is preferably 97% by mass, and more preferably 93% by mass, based on the total solid content of the radiation-sensitive resin composition. Here, the total solid content in the radiation-sensitive resin composition refers to the sum of components excluding the solvent [E] and the uneven distribution promoter described later.

<Method of synthesizing [A] polymer>
The polymer [A] can be synthesized, for example, by polymerizing a monomer giving each structural unit in a suitable solvent in the presence of a radical polymerization initiator or the like.

Examples of the radical polymerization initiator include azobisisobutyronitrile (AIBN), 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis(2-cyclopropyl). Propionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate and other azo radical initiators; benzoyl peroxide, t-butyl hydroperoxide , Peroxide radical initiators such as cumene hydroperoxide, and the like. As the radical polymerization initiator, AIBN and dimethyl 2,2'-azobisisobutyrate are preferable, and AIBN is more preferable. These radical polymerization initiators can be used alone or in combination of two or more.

Examples of the solvent used in the above polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane;
Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene;
Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide and chlorobenzene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate, methyl propionate;
Ketones such as acetone, butanone, 4-methyl-2-pentanone, 2-heptanone;
Ethers such as tetrahydrofuran, dimethoxyethane and diethoxyethane;
Examples thereof include alcohols such as methanol, ethanol, 1-propanol, 2-propanol and 4-methyl-2-pentanol. The solvent used for these polymerizations may be used alone or in combination of two or more.

The lower limit of the reaction temperature in polymerizing the polymer [A] is preferably 40°C, more preferably 50°C. On the other hand, the upper limit of the reaction temperature is preferably 150°C, more preferably 120°C. The lower limit of the reaction time in polymerizing the polymer [A] is preferably 1 hour and more preferably 2 hours. On the other hand, the upper limit of the reaction time is preferably 48 hours, more preferably 24 hours.

The lower limit of the weight average molecular weight (Mw) of the polymer [A] is preferably 1,000, more preferably 3,000, further preferably 5,000. On the other hand, the upper limit of the Mw is preferably 50,000, more preferably 20,000, even more preferably 8,000. By setting the above Mw within the above range, the coating properties of the radiation sensitive resin composition can be improved.

The lower limit of the ratio (Mw/Mn) of the above Mw to the number average molecular weight (Mn) of the polymer [A] is usually 1, and preferably 1.3. On the other hand, the upper limit of Mw/Mn is preferably 5, more preferably 3, more preferably 2, and particularly preferably 1.8. By setting the above Mw/Mn within the above range, the LWR performance, the resolution, the rectangularity of the cross-sectional shape, the depth of focus, the MEEF performance, and the film shrinkage suppression property of the radiation-sensitive resin composition can be further improved.

The Mw and Mn of the polymer in the present specification are values measured using gel permeation chromatography (GPC) under the following conditions.
GPC column: For example, two "G2000HXL", one "G3000HXL", and one "G4000HXL" from Tosoh Corporation Column temperature: 40°C
Elution solvent: Tetrahydrofuran Flow rate: 1.0 mL/min Sample concentration: 1.0 mass%
Sample injection volume: 100 μL
Detector: Differential refractometer Standard substance: Monodisperse polystyrene

<[B] acid generator>
The acid generator [B] includes —SO ₃ ^— , a first carbon atom, a second carbon atom, and two or more electron-withdrawing groups (fluorine atom, fluoroalkyl group, —SO ₃ ^— and sulfo group). And a monovalent anion and a monovalent radiation-sensitive onium cation are contained in the compound (Z). The compound (Z) has the —SO ₃ ^— group and the second carbon atom bonded to the first carbon atom, and one or both of the first carbon atom and the second carbon atom has a total of two or more electron withdrawing properties. The groups are attached.

The acid generator [B] is a substance that generates an acid upon exposure, and the acid dissociates the acid dissociable group of the polymer [A] to dissolve the acid in the developing solution in the exposed and unexposed areas of the resist film. A difference in sex is caused, and as a result, formation of a resist pattern is promoted (hereinafter, the [B] acid generator used for this purpose is also referred to as “[B1] acid generator”). However, when the [B] acid generator is used in combination with a compound capable of generating an acid stronger than the acid generated from itself, the acid generated from the above-mentioned compound can be used in the same manner as the [C] acid diffusion controller described later. It is also possible to control the diffusion phenomenon in the resist film and to exert an effect such as suppressing an undesired chemical reaction in the unexposed portion (hereinafter, the [B] acid generator used for this purpose is referred to as "[B2] acid generation". Also referred to as "agent." [B] acid generator may contain one kind or two or more kinds.

By containing the acid generator [B], the radiation-sensitive resin composition is excellent in LWR performance, resolution, rectangularity of sectional shape, depth of focus, MEEF performance, and film shrinkage suppression property. Although the reason why the radiation-sensitive resin composition has the above-mentioned constitution to exert the above-mentioned effect is not necessarily clear, it can be inferred as follows, for example. That is, in the [B] acid generator, the anion contained in the compound (Z) includes —SO ₃ ^— and two or more electron-withdrawing groups, and the first carbon atom and/or the first carbon atom bonded to this —SO ₃ ^—. When a total of two or more of the electron-withdrawing groups are bonded to the second carbon atom that is bonded to the first carbon atom, the diffusion length of the acid generated in the resist film is appropriately adjusted by the plurality of electron-withdrawing groups. Controlled to be short. As a result, it is considered that the radiation-sensitive resin composition is excellent in LWR performance, resolution, rectangularity of sectional shape, depth of focus, MEEF performance, and film shrinkage suppression property.

Examples of the electron-withdrawing group contained in the anion include an acyl group such as an acetyl group, an alkylsulfonyl group such as a methylsulfonyl group, a cyano group, a nitro group, a halogen atom (excluding a fluorine atom) such as a chlorine atom, and the like. , A monovalent hydrocarbon group having 1 to 5 carbon atoms in which a part or all of hydrogen atoms are replaced by at least one of these atoms and groups. As said hydrocarbon group, a C1-C2 alkyl group and a C1-C2 alkenyl group are preferable, and a methyl group and a vinyl group are more preferable.

The electron withdrawing group contained in the anion is preferably a group represented by the following formula (A). When the anion contains a group represented by the following formula (A), LWR performance, resolution, rectangularity of cross-sectional shape, depth of focus, MEEF performance and film shrinkage suppression property of the radiation-sensitive resin composition can be obtained. You can improve more. Although the reason for this is not clear, for example, a cyano group exhibits a particularly strong electron-withdrawing property as compared with other electron-withdrawing groups, and therefore the strength of the acid generated from the [B] acid generator is appropriately adjusted. It is thought that this is because it can be adjusted to a stronger one.

In the above formula (A), each X is independently a hydrogen atom or a cyano group. n is 0 or 1. * Indicates a binding site with a portion other than the electron-withdrawing group.

As n, 0 is preferable.

The number of the electron-withdrawing groups contained in the anion is not particularly limited as long as it is 2 or more, but is, for example, 2 or more and 10 or less, preferably 2 or more and 5 or less, and 2 or more and 4 The following are more preferable. At least a part of the electron-withdrawing group contained in the anion may be bonded to one or both of the first carbon atom and the second carbon atom, but all of them are the first carbon atom and the second carbon atom. It is preferably bound to one or both. The total number of the electron-withdrawing groups bonded to the first carbon atom and the second carbon atom is 2 or more and 5 or less, and preferably 2 or more and 4 or less.

The anion preferably contains two cyano groups as the electron-withdrawing group.

The anion may further contain at least one of a fluorine atom, a fluoroalkyl group, —SO ₃ ^— and a sulfo group, as long as it contains two or more electron withdrawing groups. Examples of the fluoroalkyl group include trifluoroalkyl groups such as trifluoromethyl group. However, when the anion contains at least one of a fluorine atom, a fluoroalkyl group, —SO ₃ ^— and a sulfo group, these groups are included in any of the anions other than the first carbon atom and the second carbon atom. It is also preferable that the same is bonded to an atom that does not apply.

It is preferable that an organic group other than the electron-withdrawing group is further bonded to one or both of the first carbon atom and the second carbon atom. That is, the anion preferably further has the organic group bonded to one or both of the first carbon atom and the second carbon atom. As described above, the organic group is bonded to one or both of the first carbon atom and the second carbon atom, whereby the diffusion length of the acid generated from the [B] acid generator can be adjusted to a more appropriate value. .. As the organic group, for example, among the groups exemplified as the monovalent organic group represented by R ¹ , R ² and R ³ in the formulas (1-1) to (1-3) described later, the electron withdrawing is selected. Those that do not correspond to a sexual group are included. As the organic group, a monovalent organic group having 2 or more carbon atoms is preferable. The anion may have only one organic group or two or more organic groups.

Examples of the monovalent radiation-sensitive onium cation contained in the anion include cations represented by the following formulas (Z-1) to (Z-3) (hereinafter, also referred to as “cations (I) to (III)”). Etc.

In the above formula (Z-1), R ^a1 , R ^a2 and R ^a3 are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted cycloalkyl having 3 to 12 carbon atoms. alkyl group, a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, or an -OSO ₂ -R ^P or _-SO 2 -R ^Q, or two or more of these groups Represents a ring structure configured by being combined with each other. R ^P and R ^Q are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted monovalent alicyclic hydrocarbon group having 5 to 25 carbon atoms, or a substituted or non-substituted one. It is a substituted monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms. k1, k2 and k3 are each independently an integer of 0 to 5. When each of R ^{a1 to} R ^a3 and R ^P and R ^Q is plural, the plural R ^{a1 to} R ^a3 and R ^P and R ^Q may be the same or different.

In the above formula (Z-2), R ^a4 is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 8 carbon atoms, or a substituted or unsubstituted 6 to 8 carbon atoms. 8 is a monovalent aromatic hydrocarbon group. k4 is an integer of 0-7. When there are plural R ^a4 's, the plural R ^a4's may be the same or different, and the plural R ^a4's may be combined with each other to form a ring structure with the carbon atom or carbon chain to which they are bonded. R ^a5 is a substituted or unsubstituted alkyl group having 1 to 7 carbon atoms, or a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 or 7 carbon atoms. k5 is an integer of 0-6. If R ^a5 is plural, plural R ^a5 may form a ring structure may also with a plurality of R ^a5 are aligned with each other atom or atomic chain they are bound be the same or different. r is an integer of 0-3. R ^a6 is a single bond or a divalent organic group having 1 to 20 carbon atoms. t is an integer of 0-2.

In the formula (Z-3), R ^a7 and R ^a8 are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted monovalent aromatic group having 6 to 12 carbon atoms. family hydrocarbon group, or an -OSO ₂ -R ^R or _-SO 2 -R ^S, or ring composed together with the carbon atom or chain of atoms or two are combined they are bound to each other of these groups Represents the structure. R ^R and R ^S are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted C 5-25 monovalent alicyclic hydrocarbon group or a substituted or non It is a substituted monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms. k6 and k7 are each independently an integer of 0 to 5. When each of R ^a7 , R ^a8 , R ^R and R ^S is plural, the plural R ^a7 , R ^a8 , R ^R and R ^S may be the same or different.

Examples of the alkyl group represented by R ^{a1 to} R ^a3 , R ^a4 , R ^a5 , R ^a7 , R ^a8 , R ^P , R ^Q , R ^R and R ^S include a methyl group, an ethyl group, an n-propyl group, a linear alkyl group such as n-butyl group;
Examples thereof include branched alkyl groups such as i-propyl group, i-butyl group, sec-butyl group and t-butyl group.

Examples of the alkoxy group represented by R ^a4 include a methoxy group, an ethoxy group, an i-propoxy group, an n-propoxy group, a t-butoxy group and an n-butoxy group.

Examples of the cycloalkyl represented by R ^{a1 to} R ^a3 include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group and the like.

Examples of the monovalent alicyclic hydrocarbon group represented by R ^P , R ^Q , R ^R and R ^S include monovalent alicyclic hydrocarbon groups represented by R ¹⁵ , R ¹⁶ and R ¹⁷ in the above formula (2). The same groups as those exemplified as the cyclic hydrocarbon group and the like can be mentioned.

Examples of the monovalent aromatic hydrocarbon group represented by R ^{a1 to} R ^a3 , R ^a7 , R ^a8 , R ^P , R ^Q , R ^R, and R ^S include a phenyl group, a tolyl group, a xylyl group, and a mesityl group. Aryl groups such as naphthyl groups;
Examples thereof include aralkyl groups such as benzyl group and phenethyl group.

Examples of the aromatic hydrocarbon group represented by R ^a4 and R ^a5 include a phenyl group, a tolyl group and a benzyl group.

Examples of the divalent organic group represented by R ^a6 include the same groups as those exemplified as the divalent organic group represented by L ¹ in the above formula (3).

R ^{a1 to} R ^a3 , R ^a4 , R ^a5 , R ^a7 , R ^a8 , R ^P , R ^Q , R ^R, and R ^S are alkyl groups, alkoxy groups, cycloalkyl groups, and monovalent aromatic hydrocarbons. Examples of the substituent that substitutes the group or the monovalent alicyclic hydrocarbon group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, a hydroxy group, a carboxy group, a cyano group, a nitro group and an alkoxy group. , An alkoxycarbonyl group, an alkoxycarbonyloxy group, an acyl group, an acyloxy group and the like. Of these, a halogen atom is preferable, and a fluorine atom is more preferable.

Examples of the ring structure formed by a plurality of R ^{a1 to} R ^a5 and R ^a7 and R ^a8 include the same ring structures as those exemplified as the ring structure formed by R ¹⁶ and R ^{17 in} the above formula (2). To be

As R ^{a1 to} R ^a3 , an unsubstituted alkyl group, an unsubstituted cycloalkyl group, a fluorinated alkyl group, an unsubstituted monovalent aromatic hydrocarbon group, —OSO ₂ —R″ and —SO ₂ — R″ is preferable, an unsubstituted cycloalkyl group, a fluorinated alkyl group and an unsubstituted monovalent aromatic hydrocarbon group are more preferable, and a cyclohexyl group is further preferable. R″ is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

As R ^a4 , an unsubstituted alkyl group, an unsubstituted alkoxy group, a fluorinated alkyl group and an unsubstituted monovalent aromatic hydrocarbon group are preferable, and an unsubstituted C 1-5 alkoxy group is more preferable. , N-butoxy groups are more preferred.

R ^a6 is preferably a single bond.

R ^a5 , R ^a7 and R ^a8 include an unsubstituted alkyl group, a fluorinated alkyl group, an unsubstituted monovalent aromatic hydrocarbon group, —OSO ₂ —R″ and —SO ₂ —R″. A fluorinated alkyl group and an unsubstituted monovalent aromatic hydrocarbon group are more preferable, and a fluorinated alkyl group is still more preferable. R″ is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

As k1, k2 and k3 in the formula (Z-1), integers of 0 to 2 are preferable, 0 and 1 are more preferable, and 0 is further preferable. As k4 in the formula (Z-2), an integer of 0 to 2 is preferable, 0 and 1 are more preferable, and 1 is still more preferable. As k5, an integer of 0 to 2 is preferable, 0 and 1 are more preferable, and 0 is further preferable. As r, 2 and 3 are preferable, and 2 is more preferable. As t, 0 and 1 are preferable, and 0 is more preferable. As k6 and k7 in the formula (Z-3), an integer of 0 to 2 is preferable, 0 and 1 are more preferable, and 0 is further preferable.

Among these, the monovalent radiation-sensitive onium cation is preferably cation (I) and cation (II), and is preferably triphenylsulfonium cation, 4-cyclohexylphenyldiphenylsulfonium cation and 4-butoxynaphthalen-1-yltetrahydro. The thiophenium cation is more preferred.

As the first compound (Z) having the anion containing the group represented by the formula (A), a compound represented by the following formula (1-1), (1-2) or (1-3) ( Hereinafter, "compound (Z-I), (Z-II) or (Z-III)" is also preferable. In formulas (1-1), (1-2) and (1-3) below, the carbon atom adjacent to E ⁻ is the first carbon atom, the first carbon atom and the carbon atom adjacent to R ¹ are the second carbon atoms. Is an atom. The compound (Z) represented by the following formula (1-1) and also represented by the following formula (1-2) and/or (1-3) is referred to as a compound (ZI). A compound (Z) represented by the following formula (1-2) and also represented by the following formula (1-3) is referred to as a compound (Z-II).

In the formulas (1-1), (1-2) and (1-3), R ¹ , R ² and R ³ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. Or a two to three or more of these groups are combined with each other to form a ring structure having 3 to 20 ring members and a carbon atom or a carbon chain to which they are bonded. E ⁻ is —SO ₃ ⁻ . A ⁺ is a monovalent radiation-sensitive onium cation. Y is an electron-withdrawing group represented by the above formula (A).

The monovalent radiation-sensitive onium cation represented by A ⁺ is the monovalent radiation-sensitive onium cation contained in the above anion.

Examples of the monovalent organic group represented by R ¹ , R ² and R ³ include a monovalent hydrocarbon group having 1 to 20 carbon atoms, and a divalent heteroatom between carbon and carbon of the hydrocarbon group. Examples thereof include a group-containing group (α), a group obtained by substituting a part or all of the hydrogen atoms contained in the above hydrocarbon group or group (α) with a monovalent hetero atom-containing group. Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms are exemplified by the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ¹⁵ , R ¹⁶ and R ¹⁷ in the above formula (2). And the same groups as those mentioned above.

Examples of the hetero atom constituting the monovalent hetero atom-containing group and the divalent hetero atom-containing group include an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a silicon atom and a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

Examples of the divalent hetero atom-containing group include -O-, -CO-, -S-, -CS-, -NR'-, and groups in which two or more of these are combined. R'is a hydrogen atom or a monovalent hydrocarbon group. Among these, -O- is preferable.

Examples of the monovalent hetero atom-containing group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, a hydroxy group, a carboxy group, a cyano group, an amino group and a sulfanyl group (-SH). .. Of these, a fluorine atom is preferred.

Examples of the ring structure having 3 to 20 ring members which is formed by combining two or more members out of R ¹ , R ² and R ³ together with the carbon atom or carbon chain to which they are bonded are, for example, an alicyclic ring having 3 to 20 ring members. Examples thereof include a structure and an aliphatic heterocyclic structure having 3 to 20 ring members.

Examples of the alicyclic structure having 3 to 20 ring members include a monocyclic alicyclic hydrocarbon structure such as a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a cycloheptane structure and a cyclooctane structure;
Examples thereof include polycyclic alicyclic hydrocarbon structures such as a norbornane structure, an adamantane structure, a tricyclodecane structure, and a tetracyclododecane structure.

Examples of the aliphatic heterocyclic structure having 3 to 20 ring members include an azacycloalkane structure such as an azacyclopentane structure and an azacyclohexane structure;
Oxacycloalkane structures such as oxacyclopentane structure and oxacyclohexane structure;
A thiacycloalkane structure such as a thiacyclopentane structure or a thiacyclohexane structure;
Examples thereof include an oxazolidine structure, a 1,4,2-dioxazolidine structure, a thiazolidine structure, and a structure represented by the following formula (K).

In the above formula (K), K ¹ and k ² are each independently a monocyclic or polycyclic alicyclic structure having 3 to 15 ring members.

Examples of the alicyclic structure represented by K ¹ and k ² include the same as those exemplified as the alicyclic structure having 3 to 20 ring members, and among these, a monocyclic alicyclic structure having 5 to 8 ring members is included. An alicyclic hydrocarbon structure of a ring and a polycyclic alicyclic hydrocarbon structure having 8 to 15 ring members are preferable, and a cyclohexane structure, a norbornane structure and an adamantane structure are more preferable.

The monovalent organic group represented by R ¹ , R ² and R ³ may be an electron-withdrawing group such as the group represented by the above formula (A). However, at least one of R ¹ , R ² and R ³ is preferably an organic group other than the electron-withdrawing group represented by the above formula (A).

At least one of R ¹ , R ² and R ³ is preferably a monovalent organic group containing at least one of an oxygen atom and a sulfur atom, or a hydrogen atom. On the other hand, R ¹ , R ² and R ³ may be a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. By setting R ¹ , R ² and R ³ to the above groups or atoms, the diffusion length of the acid generated from the compound (Z) can be adjusted to a more appropriate value.

As R ¹ in the compound (Z-I), a hydrogen atom and a hydrocarbon group having 1 to 20 carbon atoms are preferable, and a hydrogen atom is more preferable. In particular, in the compound (Z-I) in which R ¹ is a hydrogen atom, the proton contained in R ¹ is easily desorbed by the action of alkali. Therefore, in the radiation-sensitive resin composition using such a compound (Z-I) as the [B] acid generator, when the resist film to be formed is alkali-developed, the compound (Z-I) is the same as described above. It is considered that since the elimination of the protons improves the solubility, it is possible to effectively suppress the development defects caused by the poor solubility of the acid generator [B].

R ² and R ³ in the compound (Z-I) include a hydrogen atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, and a divalent hetero atom-containing group between carbon and carbon of the hydrocarbon group. The group (α) and the electron withdrawing group represented by the above formula (A) are preferable, and a hydrogen atom, a monovalent chain hydrocarbon group having 1 to 10 carbon atoms, and a monovalent oil having 3 to 15 carbon atoms. A cyclic hydrocarbon group, a group containing —COO— or —SO ₂ O— between carbon-carbon of this alicyclic hydrocarbon group, a monovalent aromatic hydrocarbon group having 6 to 15 carbon atoms, and the above formula The electron-withdrawing group represented by (A) is more preferable and includes a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a monovalent alicyclic saturated hydrocarbon group having 5 to 15 carbon atoms, and a norbornane lactone structure. A monovalent group, a monovalent group containing a norbornane sultone structure, an aryl group having 6 to 15 carbon atoms and a cyano group are more preferable, and a hydrogen atom, a methyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, a norbornane rankton-yl group. , Norbornane sultone-yl groups, fluorenyl groups and cyano groups are particularly preferred.

At least one of R ² and R ³ in the compound (Z-I) is preferably a monovalent organic group. When one of R ² and R ³ in the compound (Z-I) is an electron-withdrawing group represented by the above formula (A), the other is an electron withdrawing group represented by the above formula (A). It is preferable that it is a monovalent organic group other than the functional group.

As R ¹ and R ² in the compound (Z-II), a hydrogen atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, and a part or all of the hydrogen atoms contained in the hydrocarbon group are monovalent hetero groups. A group substituted with an atom-containing group is preferable, a hydrogen atom, a chain hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 15 carbon atoms, an aromatic hydrocarbon group having 6 to 15 carbon atoms, And a group in which some or all of the hydrogen atoms of these hydrocarbon groups are substituted with halogen atoms are more preferable, and a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, and a monovalent alicyclic group having 5 to 15 carbon atoms A saturated hydrocarbon group, an aryl group having 6 to 15 carbon atoms, and a halogenated aryl group having 6 to 15 carbon atoms are more preferable, and a hydrogen atom, a cyclohexyl group, a phenyl group and a fluorophenyl group are particularly preferable.

As R ³ in the compound (Z-II), a hydrogen atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, and a part or all of the hydrogen atoms of the hydrocarbon group are monovalent hetero atom-containing groups. A group substituted with a hydrogen atom, a chain hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 15 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 15 carbon atoms and A group obtained by substituting a part or all of hydrogen atoms of these hydrocarbon groups with a halogen atom is more preferable, and a hydrogen atom, an aryl group having 6 to 15 carbon atoms and a halogenated aryl group having 6 to 15 carbon atoms are further preferable. , Hydrogen atom, phenyl group, naphthyl group and fluorophenyl group are particularly preferable.

In addition, in the compound (Z-II), ^one of R ¹ and R ² and R ³ are combined with each other to form a ring structure having 3 to 20 ring members together with a carbon chain to which they are bonded. Is also preferable. In this case, the above-mentioned ring structure is preferably a ring structure containing an acetal structure, more preferably the ring structure represented by the above formula (K).

As R ¹ , R ² and R ³ in the compound (Z-III), a hydrogen atom and a monovalent hydrocarbon group having 1 to 20 carbon atoms are preferable, and a hydrogen atom and a chain hydrocarbon group having 1 to 10 carbon atoms. , A monovalent alicyclic hydrocarbon group having 3 to 15 carbon atoms and a monovalent aromatic hydrocarbon group having 6 to 15 carbon atoms are more preferable, and a hydrogen atom, a monovalent alicyclic group having 5 to 15 carbon atoms. A saturated hydrocarbon group and an aryl group having 6 to 15 carbon atoms are more preferable, and a hydrogen atom, a cyclohexyl group and a naphthyl group are particularly preferable.

At least one of R ¹ , R ² and R ³ in the compound (Z-III) is a monovalent organic group, and another at least one is preferably a hydrogen atom.

Examples of the compounds (Z-I) to (Z-III) include compounds represented by the following formulas.

In the above formula, A ⁺ is a monovalent radiation-sensitive onium cation.

When the [B] acid generator is used as the [B1] acid generator, the lower limit of the content of the [B] acid generator in the radiation-sensitive resin composition is 100 parts by mass of the [A] polymer. 0.1 part by mass is preferred, 1.0 part by mass is more preferred, and 5.0 parts by mass is even more preferred. On the other hand, the upper limit of the content is preferably 40 parts by mass, more preferably 20 parts by mass, and even more preferably 15 parts by mass. By setting the content of the acid generator [B] to the above range, LWR performance, resolution, rectangularity of cross-sectional shape, depth of focus, MEEF performance, and film shrinkage suppression can be further improved.

When the [B] acid generator is used as the [B2] acid generator, the lower limit of the content of the [B] acid generator in the radiation-sensitive resin composition is 100 parts by mass of the [A] polymer. 0.1 part by mass is preferred, 0.5 part by mass is more preferred, and 1.0 part by mass is even more preferred. On the other hand, the upper limit of the content is preferably 30 parts by mass, more preferably 15 parts by mass, further preferably 5 parts by mass. By setting the content of the acid generator [B] to the above range, LWR performance, resolution, rectangularity of cross-sectional shape, depth of focus, MEEF performance, and film shrinkage suppression can be further improved.

<Method for producing compound (Z)>
[Manufacturing method (1)]
The compound (Z) is represented by, for example, the above formula (1-1), and when R ¹ is a hydrogen atom (Z′-a), it can be synthesized simply and in good yield according to the following scheme.

In the above scheme, R ² , R ³ , Y, A ⁺ and E ⁻ have the same meaning as in the above formula (1-1). S ¹ is sulfite. J ⁻ is a halogen anion.

Examples of the halogen anion represented by J ⁻ include a fluorine anion, a chlorine anion, a bromine anion, an iodine anion and the like, and among these, a chlorine anion is preferable.

In a pair of carbon atoms constituting the ethylenic carbon-carbon double bond, R ² and R ³ bonded to one of the pair of carbon atoms, and the above formula (A) bonded to the other of the pair of carbon atoms. A step of adding sulfite to an unsaturated compound (z'-a) having two Y's represented, and the resulting product is optionally formed with a halogen anion and a radiation-sensitive onium cation. Compound (Z′-a) can be obtained by a method comprising a step of cation exchange with A ⁺ J ⁻ which is the compound to be prepared.

The reaction can be promoted by performing the addition reaction step under heating and reflux conditions in a solvent such as acetonitrile. In addition, the cation exchange step can be carried out in a solvent such as dichloromethane or water to accelerate the reaction. As the above-mentioned sulfite, sodium hydrogen sulfite is preferable.

The obtained product may include a by-product in which the positional relationship of R ² , R ³ or two Y's is changed in the above addition reaction step, and the like. The compound (Z'-a) can be isolated by appropriate purification.

The unsaturated compound (z'-a) can be synthesized easily and in good yield, for example, according to the following scheme.

In the above scheme, R ² , R ³ and Y have the same meaning as in formula (1-1) above.

By reacting an aldehyde compound represented by the formula (z″-a) and a compound represented by Y—CH ₂ —Y in a solvent such as methylene chloride in the presence of a base such as imidazole, the compound represented by the formula (z An unsaturated compound represented by'-a) can be obtained.

The unsaturated compound (z'-a) can be isolated by appropriately purifying the obtained product by column chromatography, recrystallization, distillation or the like.

[Manufacturing method (2)]
In the case of the compound (Z-3), for example, the compound (Z) can be synthesized simply and in good yield according to the following scheme.

In the above scheme, R ¹ , R ² , R ³ , Y, A ⁺ and E ⁻ have the same meaning as in the above formula (1-3). S ² is dithionite. J ^'is a halogen atom. a ⁺ is a monovalent cation contained in S ² . J" ^- is a halogen anion.

Examples of the halogen atom represented by J ^′ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and among these, an iodine atom is preferable.

J ^"- halogen anion represented by the fluorine anion, chlorine anion, bromine anion, iodine anion, chlorine anion is preferred among these.

As the dithionite salt represented by S ² , sodium dithionite is preferable.

It has a halogen atom J′, two carbon atoms (a third carbon atom and a fourth carbon atom), two Ys, and R ^{1 to} R ^3, and the third carbon atom has J′ and two A step of substituting a dithionite S ² for the third carbon atom and J′ of the halogen compound (z′-b) in which Y is bonded and R ^{1 to} R ³ are bonded to the fourth carbon atom. And a step of cation exchanging the obtained product with A ⁺ J″ ⁻ , which is a compound formed of a halogen anion and a radiation-sensitive onium cation, if necessary, to obtain a compound (Z-3). be able to.

The substitution reaction step can be promoted by performing the substitution reaction step in a solvent such as acetonitrile or water in the presence of sodium hydrogen carbonate or the like. Further, when a dithionite is used in the substitution reaction step, a sulfin compound is obtained in the reaction, but after that, a catalytic amount of sodium (IV) tungstate and the like and an oxidizing agent such as hydrogen peroxide solution are added. Then, it can be made into a sulfone body. Furthermore, the reaction can be promoted by performing the cation exchange step in a solvent such as dichloromethane or water.

The compound (Z-3) can be isolated by appropriately purifying the obtained product by column chromatography, recrystallization, distillation or the like.

For the compound (Z) other than the compounds (Z′-a) and (Z-3), the same method as described above can be obtained by selecting one of the formulations of the production method (1) and the production method (2). Can be synthesized by.

<[B'] other acid generator>
The [B'] other acid generator is a component other than the [B] acid generator and is a substance that generates an acid upon exposure. The radiation-sensitive resin composition contains the acid generator [B′] in addition to the acid generator [B], so that the resist pattern can be formed more easily. In particular, when the [B] acid generator is used as the [B2] acid generator, the radiation-sensitive resin composition contains [B′] other acid generator, and thus the [B′] is mainly used. The acid generated from the acid generator dissociates the acid dissociable group of the polymer [A] to cause a difference in solubility in a developing solution between the exposed portion and the unexposed portion, and as a result, a resist pattern is formed. You can The [B′] acid generator contained in the radiation-sensitive resin composition may be in the form of a low-molecular compound (hereinafter also referred to as “[B′] other acid generator” as appropriate), or as a polymer. The form may be incorporated as a part or both of them.

Examples of [B'] other acid generators include onium salt compounds, N-sulfonyloxyimide compounds, sulfonimide compounds, halogen-containing compounds, diazoketone compounds, and the like.

Examples of onium salt compounds include sulfonium salts, tetrahydrothiophenium salts, iodonium salts, phosphonium salts, diazonium salts, pyridinium salts and the like.

Specific examples of [B'] other acid generators include the compounds described in paragraphs [0080] to [0113] of JP2009-134088A.

Examples of the acid generated from [B'] other acid generator include sulfonic acid, imidic acid, amic acid, methide acid, phosphinic acid, carboxylic acid and the like. Among these, sulfonic acid, imidic acid, amic acid and methide acid are preferable.

Examples of the [B'] other acid generator include a compound represented by the following formula (4) (hereinafter, also referred to as "[B1'] other acid generator") and the like.

In the above formula (4), A ⁻ is a monovalent sulfonate anion, a monovalent imide acid anion, a monovalent amic acid anion, or a monovalent methide acid anion. Z ⁺ is a monovalent radiation-sensitive onium cation.

In the case of [B1′] other acid generator, sulfonic acid is generated when A ⁻ in the above formula (4) is a sulfonate anion (hereinafter, also referred to as “[B1a′] other acid generator”). When A ⁻ is an imido acid anion (hereinafter, also referred to as “[B1b′] other acid generator”), imido acid is generated. When A ⁻ is an amic acid anion (hereinafter, also referred to as “[B1c′] other acid generator”), an amic acid is generated. When A ⁻ is a methide acid anion (hereinafter, also referred to as “[B1d′] other acid generator”), methide acid is generated.

Examples of [B1a′] other acid generators include compounds represented by the following formula (4-1) (hereinafter, also referred to as “compound (4-1)”) and the like. [B1′] Since the other acid generator has the following structure, the diffusion length of the acid generated by exposure in the resist film is more appropriate due to the interaction with the structural unit (I) of the polymer [A]. As a result, the LWR performance, resolution, rectangularity of cross-sectional shape, depth of focus, MEEF performance, and film shrinkage suppression property of the radiation-sensitive resin composition can be further improved.

In the above formula (4-1), R ^p1 is a monovalent group containing a ring structure having 6 or more ring members. R ^p2 is a divalent linking group. R ^p3 and R ^p4 are each independently a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. R ^p5 and R ^p6 are each independently a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. n ^p1 is an integer of 0 to 10. n ^p2 is an integer of 0 to 10. ^np3 is an integer of 0-10. However, n ^p1 +n ^p2 +n ^p3 is 1 or more and 30 or less. When n ^p1 is 2 or more, a plurality of R ^p2 may be the same or different. When n ^p2 is 2 or more, a plurality of R ^p3 may be the same or different, and a plurality of R ^p4 may be the same or different. When n ^p3 is 2 or more, a plurality of R ^p5 may be the same or different, and a plurality of R ^p6 may be the same or different. Z ⁺ is a monovalent radiation-sensitive onium cation.

Examples of the monovalent group represented by R ^p1 containing a ring structure having 6 or more ring members include a monovalent group containing an alicyclic structure having 6 or more ring members and an aliphatic heterocyclic structure having 6 or more ring members. Examples thereof include a monovalent group, a monovalent group containing an aromatic ring structure having 6 or more ring members, and a monovalent group containing an aromatic heterocyclic structure having 6 or more ring members.

Examples of the alicyclic structure having 6 or more ring members include a monocyclic alicyclic saturated hydrocarbon structure such as a cyclohexane structure, a cycloheptane structure, a cyclooctane structure, a cyclononane structure, a cyclodecane structure and a cyclododecane structure;
A monocyclic alicyclic unsaturated hydrocarbon structure such as a cyclohexene structure, a cycloheptene structure, a cyclooctene structure, or a cyclodecene structure;
A polycyclic alicyclic saturated hydrocarbon structure such as a norbornane structure, an adamantane structure, a tricyclodecane structure, or a tetracyclododecane structure;
Examples thereof include polycyclic alicyclic unsaturated hydrocarbon structures such as norbornene structure and tricyclodecene structure.

Examples of the aliphatic heterocyclic structure having 6 or more ring members include a lactone structure such as a hexanolactone structure and a norbornane lactone structure;
Sultone structures such as hexanosultone structure and norbornane sultone structure;
Oxygen atom-containing heterocyclic structures such as oxacycloheptane structure and oxanorbornane structure;
Nitrogen atom-containing heterocyclic structure such as azacyclohexane structure and diazabicyclooctane structure;
Examples thereof include a sulfur atom-containing heterocyclic structure such as a thiacyclohexane structure and a thianorbornane structure.

Examples of the aromatic ring structure having 6 or more ring members include a benzene structure, a naphthalene structure, a phenanthrene structure, and an anthracene structure.

Examples of the aromatic heterocyclic structure having 6 or more ring members include an oxygen atom-containing heterocyclic structure such as a furan structure, a pyran structure, and a benzopyran structure;
Examples thereof include a nitrogen atom-containing heterocyclic structure such as a pyridine structure, a pyrimidine structure, and an indole structure.

As a minimum of the number of ring members of the ring structure of R ^p1 , 7 is preferable, 8 is more preferable, 9 is further preferable, and 10 is particularly preferable. On the other hand, as the upper limit of the number of ring members, 15 is preferable, 14 is more preferable, 13 is further preferable, and 12 is particularly preferable. By setting the number of ring members in the above range, the diffusion length of the acid can be further appropriately shortened, and as a result, LWR performance, resolution, and rectangularity of the cross-sectional shape of the radiation-sensitive resin composition. The depth of focus, the MEEF performance, and the film shrinkage suppression property can be further improved.

Part or all of the hydrogen atoms ^{contained in} the ring structure of R ^p1 may be substituted with a substituent. Examples of the substituent include a fluorine atom, a chlorine atom, a bromine atom, a halogen atom such as an iodine atom, a hydroxy group, a carboxy group, a cyano group, a nitro group, an alkoxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, an acyl group, Examples thereof include an acyloxy group. Of these, a hydroxy group is preferred.

R ^p1 is preferably a monovalent group containing an alicyclic structure having 6 or more ring members and a monovalent group containing an aliphatic heterocyclic structure having 6 or more ring members, and 1 containing an alicyclic structure having 9 or more ring members. A monovalent group and a monovalent group containing an aliphatic heterocyclic structure having 9 or more ring members are more preferable, and an adamantyl group, a hydroxyadamantyl group, a norbornane lactone-yl group, a norbornane sultone-yl group and 5-oxo-4-oxa. A tricyclo[4.3.1.1 ^3,8 ]undecane-yl group is more preferable, and an adamantyl group is particularly preferable.

Examples of the divalent linking group represented by R ^p2 include a carbonyl group, an ether group, a carbonyloxy group, a sulfide group, a thiocarbonyl group, a sulfonyl group, and a divalent hydrocarbon group. Among these, a carbonyloxy group, a sulfonyl group, an alkanediyl group and a divalent alicyclic saturated hydrocarbon group are preferable, a carbonyloxy group and a divalent alicyclic saturated hydrocarbon group are more preferable, and a carbonyloxy group And norbornanediyl group are more preferable, and carbonyloxy group is particularly preferable.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^p3 and R ^p4 include an alkyl group having 1 to 20 carbon atoms. Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ^p3 and R ^p4 include fluorinated alkyl groups having 1 to 20 carbon atoms. As R ^p3 and R ^p4 , a hydrogen atom, a fluorine atom and a fluorinated alkyl group are preferable, a fluorine atom and a perfluoroalkyl group are more preferable, and a fluorine atom and a trifluoromethyl group are further preferable.

Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ^p5 and R ^p6 include a fluorinated alkyl group having 1 to 20 carbon atoms. As R ^p5 and R ^p6 , a fluorine atom and a fluorinated alkyl group are preferable, a fluorine atom and a perfluoroalkyl group are more preferable, a fluorine atom and a trifluoromethyl group are further preferable, and a fluorine atom is particularly preferable.

As n ^p1 , an integer of 0 to 5 is preferable, an integer of 0 to 3 is more preferable, an integer of 0 to 2 is further preferable, and 0 and 1 are particularly preferable.

As n ^p2 , an integer of 0 to 5 is preferable, an integer of 0 to 2 is more preferable, 0 and 1 are further preferable, and 0 is particularly preferable.

As a minimum of ^np3 , 1 is preferred and 2 is more preferred. By setting ^np3 to 1 or more, the strength of the acid generated from the compound (4-1) can be increased, and as a result, the LWR performance, resolution, and rectangular shape of the cross section of the radiation-sensitive resin composition. , The depth of focus, the MEEF performance, and the film shrinkage suppression property can be further improved. The upper limit of n ^p3 is preferably 4, more preferably 3, and even more preferably 2.

The lower limit of the ^{n p1 + n p2 + n p3} , 2 are preferable, 4 is more preferable. ^{n p1 +} n p2 + upper limit of the ^{n p3} is 20, and more preferably 10.

Examples of the monovalent radiation-sensitive onium cation represented by Z ⁺ include the same cations as the monovalent radiation-sensitive onium cation included in the compound (Z).

[B1a′] Other acid generators include, for example, compounds represented by the following formulas (4-1-1) to (4-1-15) (hereinafter, “compounds (4-1-1) to (4-1)). -1-15)") and the like. [B1b′] Other acid generators include, for example, compounds represented by the following formulas (4-2-1) to (4-2-3) (hereinafter, “compounds (4-2-1) to (4-2)). -2-3)"). [B1c′] As another acid generator, for example, a compound represented by the following formula (4-3-1) or formula (4-3-2) (hereinafter, “compound (4-3-1), ( 4-3-2)”) and the like. [B1d′] As another acid generator, for example, a compound represented by the following formula (4-4-1) or formula (4-4-2) (hereinafter, “compound (4-4-1), ( 4-4-2)” is also used.

Formulas (4-1-1) to (4-1-15), (4-2-1) to (4-2-3), (4-3-1), (4-3-2), In (4-4-1) and (4-4-2), Z ⁺ is a monovalent radiation-sensitive onium cation.

As the [B1′] other acid generator, [B1a′] other acid generator is preferable, and the compounds (4-1-1), (4-1-2), (4-1-11) and ( 4-1-12) is more preferable.

[B1′] As another acid generator, an onium salt compound is preferable, a sulfonium salt and a tetrahydrothiophenium salt are more preferable, and a triphenylsulfonium salt and a 4-butoxynaphthalen-1-yltetrahydrothiophenium salt are further preferable. preferable.

Further, as the other acid generator of [B'], a polymer in which the structure of the acid generator is incorporated as a part of the polymer is also preferable. Examples of such a polymer include a polymer having a structural unit represented by the following formula (4-1').

In the above formula (4-1′), R ^p7 is a hydrogen atom or a methyl group. L ⁴ is a single bond or —COO— or a divalent carbonyloxy hydrocarbon group. R ^p8 is a fluorinated alkanediyl group having 1 to 10 carbon atoms. Z ⁺ has the same ^{meaning as} in the above formula (4).

As R ^p7 , a hydrogen atom and a methyl group are preferable, and a methyl group is more preferable, from the viewpoint of the copolymerizability of the monomer giving the structural unit represented by the above formula (4-1′).

As L ⁴ , a divalent carbonyloxy hydrocarbon group is preferable, and a carbonyloxyalkanediyl group and a carbonylalkanediylarenediyl group are more preferable.

As R ^p8 , a fluorinated alkanediyl group having 1 to 4 carbon atoms is preferable, a perfluoroalkanediyl group having 1 to 4 carbon atoms is more preferable, and a hexafluoropropanediyl group is further preferable.

When the radiation-sensitive resin composition contains [B'] other acid generator, the lower limit of the content of [B'] other acid generator is 100 parts by mass of [A] polymer. 0.1 part by mass is preferred, 1.0 part by mass is more preferred, and 5.0 parts by mass is even more preferred. On the other hand, the upper limit of the content is preferably 40 parts by mass, more preferably 20 parts by mass, and even more preferably 10 parts by mass. [B′] By setting the content of the other acid generator within the above range, the sensitivity and developability of the radiation-sensitive resin composition can be improved, and as a result, the LWR performance, the resolution, and the rectangular cross section are obtained. , The depth of focus, the MEEF performance, and the film shrinkage suppression property can be further improved. [B'] The other acid generator may contain one kind or two or more kinds.

<[C] Acid diffusion controller>
The radiation-sensitive resin composition may contain a [C] acid diffusion controller, if necessary. In particular, when the [B] acid generator is used as the [B1] acid generator, it may be used in combination with the [C] acid diffusion controller. The [C] acid diffusion controller controls the diffusion phenomenon of the acid generated from the [B] acid generator, [B′] other acid generator, etc. in the resist film by exposure, and an unfavorable chemical reaction in the non-exposed area. Has the effect of suppressing. Further, the storage stability of the radiation-sensitive resin composition is improved, and the resolution as a resist is further improved. Further, it is possible to suppress the change in the line width of the resist pattern due to the change in the leaving time from the exposure to the development treatment, and it is possible to obtain the radiation-sensitive resin composition having excellent process stability. As a form of containing the [C] acid diffusion controller in the radiation-sensitive resin composition, a form of a free compound (hereinafter, also appropriately referred to as "[C] acid diffusion controller") may be included as a part of the polymer. It may be an integrated form or both forms.

Examples of the [C] acid diffusion control agent include compounds represented by the following formula (B) (hereinafter, also referred to as “nitrogen-containing compound (I)”), compounds having two nitrogen atoms in the same molecule (hereinafter, “Nitrogen-containing compound (II)”, compound having three nitrogen atoms (hereinafter, also referred to as “nitrogen-containing compound (III)”), amide group-containing compound, urea compound, nitrogen-containing heterocyclic compound and the like. To be

In the above formula (B), R ²⁰ , R ²¹ and R ²² are each independently a hydrogen atom, an optionally substituted linear, branched or cyclic alkyl group, an aryl group or an aralkyl group. ..

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

Examples of the nitrogen-containing compound (II) include ethylenediamine, N,N,N',N'-tetramethylethylenediamine and the like.

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

Examples of the amide group-containing compound include formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, benzamide, pyrrolidone and N-methylpyrrolidone. To be

Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea and tributylthiourea.

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

As the nitrogen-containing organic compound, a compound having an acid dissociable group can also be used. Examples of the nitrogen-containing organic compound having such an acid dissociable group include Nt-butoxycarbonylpiperidine, Nt-butoxycarbonylimidazole, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2. -Phenylbenzimidazole, N-(t-butoxycarbonyl)di-n-octylamine, N-(t-butoxycarbonyl)diethanolamine, N-(t-butoxycarbonyl)dicyclohexylamine, N-(t-butoxycarbonyl)diphenylamine , Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-amyloxycarbonyl-4-hydroxypiperidine and the like.

Further, as the [C] acid diffusion controller, a photodegradable base which is exposed to light to generate a weak acid can be used. Examples of the photodegradable base include an onium salt compound which is decomposed by exposure and loses acid diffusion controllability. Examples of the onium salt compound include a sulfonium salt compound represented by the following formula (5-1) and an iodonium salt compound represented by the following formula (5-2).

In formulas (5-1) and (5-2), R ^{23 to} R ²⁷ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a hydroxy 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 (5-3). However, R ^β is an alkyl group, an aryl group or an aralkyl group.

In the above formula (5-3), R ²⁸ represents a linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched fluorinated alkyl group having 1 to 12 carbon atoms, or 1 carbon atom. To 12 straight-chain or branched alkoxy groups. u is an integer of 0-2. When u is 2, two R ^28's may be the same or different.

Examples of the photodegradable base include compounds represented by the following formulae.

Of these, the photo-degradable base is preferably a sulfonium salt, more preferably a triarylsulfonium salt, and further preferably triphenylsulfonium salicylate or triphenylsulfonium 10-camphorsulfonate.

When the radiation-sensitive resin composition contains the [C] acid diffusion controlling agent, the lower limit of the content of the [C] acid diffusion controlling agent is 0.1 with respect to 100 parts by mass of the [A] polymer. A mass part is preferable, a 0.3 mass part is more preferable, and 1 mass part is still more preferable. On the other hand, the upper limit of the content is preferably 20 parts by mass, more preferably 15 parts by mass, and even more preferably 10 parts by mass.

<[D] polymer>
The polymer [D] is a polymer having a mass content of fluorine atoms higher than that of the polymer [A]. In the resist film formed by the radiation-sensitive resin composition containing the [D] polymer, the distribution of the [D] polymer in the film tends to be unevenly distributed in the vicinity of the resist film surface due to its oil-repellent characteristic. Therefore, it is possible to prevent the acid generator, the acid diffusion control agent, and the like from eluting into the immersion medium during immersion exposure. Further, due to the water-repellent characteristic of the polymer [D], the advancing contact angle between the resist film and the immersion medium can be controlled within a desired range, and the occurrence of bubble defects can be suppressed. Furthermore, the receding contact angle between the resist film and the immersion medium becomes high, and high-speed scanning exposure is possible without leaving any water droplets. As described above, when the radiation-sensitive resin composition contains the [D] polymer, a resist film suitable for the liquid immersion exposure method can be formed.

The lower limit of the fluorine atom content of the polymer [D] is preferably 1% by mass, more preferably 2% by mass, further preferably 4% by mass, and particularly preferably 7% by mass. The upper limit of the fluorine atom content is preferably 60% by mass, more preferably 40% by mass, and even more preferably 30% by mass. The fluorine atom content rate (mass %) of the polymer can be calculated from the structure of the polymer obtained by ¹³ C-NMR spectrum measurement or the like.

The polymer [D] preferably has a structural unit (Da), a structural unit (Db) described below, or a combination thereof. The polymer [D] may have one type or two or more types of the structural unit (Da) and the structural unit (Db), respectively.

[Structural unit (Da)]
The structural unit (Da) is a structural unit represented by the following formula (6a). The polymer [D] has a structural unit (Da), whereby the fluorine atom content can be adjusted.

In the above formula (6a), R ^D is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. G represents a single bond, an oxygen atom, a sulfur _{atom, -CO-O -, - SO} 2 -O-NH -, - is CO-NH- or -O-CO-NH-. R ^E is a monovalent fluorinated chain hydrocarbon group having 1 to 6 carbon atoms or a monovalent fluorinated aliphatic alicyclic hydrocarbon group having 4 to 20 carbon atoms.

Examples of the monovalent fluorinated chain hydrocarbon group having 1 to 6 carbon atoms represented by R ^E include, for example, trifluoromethyl group, 2,2,2-trifluoroethyl group, perfluoroethyl group, and 2,2. , 3,3,3-pentafluoropropyl group, 1,1,1,3,3,3-hexafluoropropyl group, perfluoro n-propyl group, perfluoro i-propyl group, perfluoro n-butyl group, Examples thereof include a perfluoro i-butyl group, a perfluoro t-butyl group, a 2,2,3,3,4,4,5,5-octafluoropentyl group and a perfluorohexyl group.

Examples of the monovalent fluorinated alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ^E include a monofluorocyclopentyl group, a difluorocyclopentyl group, a perfluorocyclopentyl group, a monofluorocyclohexyl group, a difluorocyclopentyl group, Examples thereof include a perfluorocyclohexylmethyl group, a fluoronorbornyl group, a fluoroadamantyl group, a fluorobornyl group, a fluoroisobornyl group, a fluorotricyclodecyl group and a fluorotetracyclodecyl group.

Examples of the monomer giving the structural unit (Da) include linear partially fluorinated alkyl (meth)acrylic acid esters such as 2,2,2-trifluoroethyl (meth)acrylic acid ester;
Branched-chain partially fluorinated alkyl (meth)acrylic acid ester such as 1,1,1,3,3,3-hexafluoro i-propyl (meth)acrylic acid ester;
Linear perfluoroalkyl (meth)acrylic acid ester such as perfluoroethyl (meth)acrylic acid ester;
(Meth)acrylic acid ester having a fluorinated chain hydrocarbon group such as branched-chain perfluoroalkyl(meth)acrylic acid ester such as perfluoro i-propyl(meth)acrylic acid ester,
Monocyclic fluorinated alicyclic saturated hydrocarbon group-containing (meth)acrylic acid such as perfluorocyclohexylmethyl (meth)acrylic acid ester, monofluorocyclopentyl (meth)acrylic acid ester, and perfluorocyclopentyl (meth)acrylic acid ester ester;
Fluorinated norbornyl (meth)acrylic acid ester-containing polycyclic fluorinated alicyclic saturated hydrocarbon group-containing (meth)acrylic acid ester-containing fluorinated alicyclic hydrocarbon group-containing (meth)acrylic acid ester, etc. Can be mentioned. Among these, (meth)acrylic acid ester having a fluorinated chain hydrocarbon group is preferable, linear partially fluorinated alkyl (meth)acrylic acid ester is more preferable, and 2,2,2-trifluoroethyl (meth ) Acrylic acid esters are more preferred.

When the polymer [D] has the structural unit (Da), the lower limit of the content of the structural unit (Da) is preferably 5 mol% based on all the structural units constituting the polymer [D], and 15 Mol% is more preferable, and 30 mol% is further preferable. On the other hand, the upper limit of the content ratio is preferably 95 mol%, more preferably 75 mol%, further preferably 50 mol%. By setting the content ratio of the structural unit (Da) in the above range, a higher dynamic contact angle can be exhibited on the surface of the resist film formed by the radiation-sensitive resin composition during immersion exposure.

[Structural unit (Db)]
The structural unit (Db) is a structural unit represented by the following formula (6b). Since the polymer [D] has the structural unit (Db), the fluorine atom content can be adjusted, and the water repellency and hydrophilicity before and after the alkali development can be changed.

In the above formula (6b), R ^F is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ²⁹ is a (s+1)-valent hydrocarbon group having 1 to 20 carbon atoms, and has an oxygen atom, a sulfur atom, a —NR′—, a carbonyl group, a —CO—O— or a R ³⁰ -side terminal of R ^29. It also includes a structure in which -CO-NH- is bonded. R'is a hydrogen atom or a monovalent organic group. R ³⁰ is a single bond, a divalent chain hydrocarbon group having 1 to 10 carbon atoms or a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms. X ² is a divalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms. A ¹ represents an oxygen atom, -NR "-, - CO- O- * or _-SO 2 -O- * .R" is a hydrogen atom or a monovalent organic group. * Indicates a binding site that binds to R ³¹ . R ³¹ is a hydrogen atom or a monovalent organic group. s is an integer of 1 to 3. However, when s is 2 or 3, a plurality of R ³⁰ , X ² , A ¹ and R ³¹ may be the same or different.

When R ³¹ is a hydrogen atom, it is preferable because the solubility of the polymer [D] in an alkali developing solution can be improved.

Examples of the monovalent organic group represented by R ³¹ include an acid dissociable group, an alkali dissociable group, and a hydrocarbon group having 1 to 30 carbon atoms which may have a substituent.

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

In the above formulas (6b-1) to (6b-3), R ^29′ is a divalent linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms. R ^F , X ² , R ³¹ and s have the same meaning as in the above formula (6b). When s is 2 or 3, a plurality of X ² and R ³¹ may be the same or different.

When the [D] polymer has the structural unit (Db), the lower limit of the content ratio of the structural unit (Db) is preferably 5 mol% with respect to all the structural units constituting the [D] polymer, and 15 Mol% is more preferable, and 30 mol% is further preferable. On the other hand, the upper limit of the content ratio is preferably 90 mol%, more preferably 75 mol%, and even more preferably 60 mol%. By setting the content ratio of the structural unit (Db) within the above range, the dynamic contact angle can be effectively reduced when the resist film surface formed from the radiation-sensitive resin composition is alkali-developed. ..

[Structural unit (Dc)]
The polymer [D] may have a structural unit containing an acid dissociable group (hereinafter, also referred to as “structural unit (Dc)”) in addition to the structural units (Da) and (Db) (however, Excluding those corresponding to the structural units (Da) to (Db)). When the polymer [D] has the structural unit (Dc), the resulting resist pattern has a better shape. Examples of the structural unit (Dc) include the same structural units as those exemplified as the structural unit (I) in the above-mentioned [A] polymer.

When the [D] polymer has a structural unit (Dc), the lower limit of the content ratio of the structural unit (Dc) is preferably 1 mol% based on all structural units constituting the [D] polymer, and 5 mol. % Is more preferable, and 10 mol% is further preferable. On the other hand, the upper limit of the content ratio is preferably 90 mol%, more preferably 60 mol%, even more preferably 40 mol%.

[Other structural units]
Further, the polymer [D] contains, for example, a structural unit containing an alkali-soluble group, a lactone structure, a cyclic carbonate structure, a sultone structure or a combination thereof, and an alicyclic group, in addition to the above structural units. It may have another structural unit such as a structural unit. Examples of the alkali-soluble group include a carboxy group, a sulfonamide group, a sulfo group and the like. Examples of the structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof include the same structural units as those exemplified for the structural unit (II) in the above-mentioned [A] polymer.

The upper limit of the content of the other structural unit is preferably 30 mol% and more preferably 20 mol% with respect to all structural units constituting the [D] polymer.

When the radiation-sensitive resin composition contains the [D] polymer, the lower limit of the content of the [D] polymer is preferably 0.5 parts by mass with respect to 100 parts by mass of the [A] polymer. 1 part by mass is more preferable, and 2 parts by mass is further preferable. On the other hand, the upper limit of the content is preferably 20 parts by mass, more preferably 15 parts by mass, and even more preferably 10 parts by mass. By setting the content of the polymer [D] in the above range, the resist film formed by the radiation-sensitive resin composition can be made more suitable for the immersion exposure method.

<[E] solvent>
The [E] solvent used in the radiation-sensitive resin composition is at least the [A] polymer and [B] acid generator, and optionally [B'] other acid generator and [C] acid diffusion. The solvent is not particularly limited as long as it is a solvent that can dissolve or disperse the control body and the optional component such as the [D] polymer.

Examples of the [E] solvent include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents and the like.

Examples of the alcohol solvent include an aliphatic monoalcohol solvent having 1 to 18 carbon atoms such as 4-methyl-2-pentanol and n-hexanol;
An alicyclic monoalcohol solvent having 3 to 18 carbon atoms such as cyclohexanol;
A polyhydric alcohol solvent having 2 to 18 carbon atoms such as 1,2-propylene glycol;
Examples thereof include polyhydric alcohol partial ether solvents having 3 to 19 carbon atoms such as propylene glycol monomethyl ether.

Examples of ether solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, diheptyl ether;
Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran;
Examples thereof include aromatic ring-containing ether solvents such as diphenyl ether and anisole.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, 2-heptanone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, Chain ketone type solvents such as di-iso-butyl ketone and trimethylnonanone:
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone:
2,4-pentanedione, acetonylacetone, acetophenone and the like can be mentioned.

Examples of the amide solvent include cyclic amide solvents such as N,N′-dimethylimidazolidinone and N-methylpyrrolidone;
Chain amide solvents such as N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropionamide and the like can be mentioned.

Examples of the ester solvent include monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate;
Polyhydric alcohol carboxylate solvent such as propylene glycol acetate;
Polyhydric alcohol partial ether carboxylate solvent such as propylene glycol monomethyl ether acetate;
Polycarboxylic acid diester solvent such as diethyl oxalate;
Examples thereof include carbonate-based solvents such as dimethyl carbonate and diethyl carbonate.

Examples of the hydrocarbon solvent include, for example, n-pentane, n-hexane, and other aliphatic hydrocarbon solvents having 5 to 12 carbon atoms;
Examples thereof include aromatic hydrocarbon solvents having 6 to 16 carbon atoms such as toluene and xylene.

Among these, ester solvents and ketone solvents are preferable, polyhydric alcohol partial ether carboxylate solvents and cyclic ketone solvents are more preferable, and propylene glycol monomethyl ether acetate and cyclohexanone are further preferable. The radiation-sensitive resin composition may contain one or more solvents [E].

<[F] uneven distribution promoter>
The [F] uneven distribution accelerator has an effect of more efficiently segregating the [D] polymer on the surface of the resist film when the radiation-sensitive resin composition contains the [D] polymer. When the radiation-sensitive resin composition contains the [F] uneven distribution promoter, the addition amount of the [D] polymer can be made smaller than in the conventional case. Therefore, without impairing the resolution and LWR performance of the radiation-sensitive resin composition, it is possible to suppress the elution of components from the resist film into the immersion liquid and speed up the immersion exposure by high-speed scanning. As a result, liquid crystal-derived defects such as watermark defects can be suppressed. Examples of the compound that can be used as the [F] uneven distribution promoter include a low molecular compound having a relative dielectric constant of 30 or more and 200 or less and a boiling point of 100° C. or more at 1 atm. Specific examples of such a compound include a lactone compound, a carbonate compound, a nitrile compound, and a polyhydric alcohol.

Examples of the lactone compound include γ-butyrolactone, valerolactone, mevalonic lactone, norbornane lactone, and the like. Examples of the carbonate compound include propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate and the like. Examples of the nitrile compound include succinonitrile and the like. Examples of the polyhydric alcohol include glycerin and the like.

When the radiation-sensitive resin composition contains the [F] uneven distribution promoter, the lower limit of the content of the [F] uneven distribution promoter is 1 part by mass relative to 100 parts by mass of the [A] polymer. Is preferable, 5 parts by mass is more preferable, 10 parts by mass is further preferable, and 20 parts by mass is particularly preferable. On the other hand, the upper limit of the content is preferably 500 parts by mass, more preferably 200 parts by mass, further preferably 100 parts by mass, and particularly preferably 50 parts by mass.

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

[Surfactant]
The surfactant used in the radiation-sensitive resin composition has an effect of improving coatability, striation, developability and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol diether. Examples thereof include nonionic surfactants such as stearate. Commercially available surfactants include KP341 (produced by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, same No. 95 (above, Kyoeisha Chemical Co., Ltd.), Ftop EF301, EF303, EF352 (above, Tochem Products Co., Ltd.), Megafac F171, F173 (above, DIC Co.), Florard FC430, FC431 (above) , Sumitomo 3M), Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (above, Asahi Glass Industry). Manufactured by the company) and the like. The upper limit of the content of the surfactant is preferably 2 parts by mass with respect to 100 parts by mass of the polymer [A].

[Alicyclic skeleton-containing compound]
The alicyclic skeleton-containing compound used in the radiation-sensitive resin composition has an effect of improving dry etching resistance, pattern shape, adhesion to a substrate, and the like.

Examples of the alicyclic skeleton-containing compound include adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and t-butyl 1-adamantanecarboxylate;
Deoxycholic acid esters such as t-butyl deoxycholic acid, t-butoxycarbonylmethyl deoxycholic acid, and 2-ethoxyethyl deoxycholic acid;
Lithocholic acid esters such as t-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid and 2-ethoxyethyl lithocholic acid;
3-[2-hydroxy-2,2-bis(trifluoromethyl)ethyl]tetracyclo[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 ]nonane and the like can be mentioned.

The upper limit of the content of the alicyclic skeleton-containing compound in the radiation-sensitive resin composition is preferably 5 parts by mass with respect to 100 parts by mass of the [A] polymer.

[Sensitizer]
The sensitizer has an action of increasing the amount of acid produced from the [B] acid generator, [B'] other acid generator, etc., and the "apparent sensitivity" of the radiation-sensitive resin composition. Has the effect of improving ".

Examples of the sensitizer used in the radiation-sensitive resin composition include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, and phenothiazines. ..

The upper limit of the content of the sensitizer in the radiation-sensitive resin composition is preferably 2 parts by mass with respect to 100 parts by mass of the [A] polymer.

<Method for preparing radiation-sensitive resin composition>
The radiation-sensitive resin composition is, for example, [A] polymer and [B] acid generator, and optionally [B′] other acid generator, [C] acid diffusion controller, [C] It can be prepared by mixing D] polymer and [E] solvent and other optional components at a predetermined ratio, and preferably filtering the resulting mixture with, for example, a filter having a pore size of about 0.2 μm. The lower limit of the solid content concentration of the radiation-sensitive resin composition is preferably 0.1% by mass, more preferably 0.5% by mass, and further preferably 1% by mass. On the other hand, the upper limit of the solid content concentration is preferably 50% by mass, more preferably 30% by mass, and further preferably 10% by mass.

<Method of forming resist pattern>
The resist pattern forming method comprises a step of coating the radiation-sensitive resin composition on one surface side of the substrate (hereinafter, also referred to as “coating step”), and a resist film obtained by the coating. (Hereinafter also referred to as "exposure step") and a step of developing the exposed resist film (hereinafter also referred to as "developing step").

According to the resist pattern forming method, since the radiation-sensitive resin composition described above is used, the LWR is small, the resolution is high, and the cross section is excellent while exhibiting excellent depth of focus, MEEF performance, and film shrinkage suppression property. It is possible to form a resist pattern having an excellent rectangular shape. Each step will be described below.

[Coating process]
In this step, the radiation-sensitive resin composition is applied to one surface side of the substrate to form a resist film. Examples of the substrate on which the resist film is formed include conventionally known substrates such as a silicon wafer and a wafer covered with silicon dioxide, aluminum or the like. In addition, an organic or inorganic antireflection film disclosed in, for example, Japanese Patent Publication No. 6-12452 or Japanese Patent Application Laid-Open No. 59-93448 may be previously formed on the substrate. Examples of the coating method include spin coating, spin coating, and roll coating. After coating, if necessary, prebaking (PB) may be performed in order to remove volatile components such as the [E] solvent of the radiation-sensitive resin composition. The lower limit of the PB temperature is preferably 60°C, more preferably 80°C. On the other hand, the upper limit of the temperature is preferably 140°C, more preferably 120°C. The lower limit of the PB time is preferably 5 seconds, more preferably 10 seconds. On the other hand, the upper limit of the above time is preferably 600 seconds, more preferably 300 seconds. The lower limit of the average thickness of the formed resist film is preferably 10 nm, more preferably 20 nm. On the other hand, the upper limit of the average thickness is preferably 1,000 nm, more preferably 500 nm.

In the case of performing immersion exposure with the radiation-sensitive resin composition containing no water-repellent polymer additive, for the purpose of avoiding direct contact between the immersion liquid and the resist film on the resist film. A protective film for immersion that is insoluble in the immersion liquid may be provided. As the liquid immersion protective film, a solvent peelable protective film that is peeled off with a solvent before the developing step (see JP 2006-227632 A) and a developer peelable protective film that is peeled off at the same time as development in the developing step ( Either WO 2005/069076 or WO 2006/035790) may be used. However, from the viewpoint of throughput, it is preferable to use a developing solution peeling type protective film for immersion.

[Exposure process]
In this step, the resist film formed in the resist film forming step is irradiated with exposure light through a photomask (in some cases, through a liquid immersion medium such as water) and exposed. The exposure light may be, for example, visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light (EUV), electromagnetic waves such as X-rays and γ-rays, and charged particle beams such as electron rays and α-rays, depending on the line width of a desired pattern. And so on. Among these, far ultraviolet rays, EUV and electron beams are preferable, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), EUV and electron rays are more preferable, ArF excimer laser light, EUV and electron rays are preferable. More preferable.

When the exposure is performed by immersion exposure, examples of the immersion liquid used include water and a fluorine-based inert liquid. The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has a temperature coefficient of refractive index as small as possible from the viewpoint of minimizing distortion of the optical image projected on the film. In the case of excimer laser light (wavelength 193 nm), it is preferable to use water from the viewpoint of easy availability and easy handling in addition to the above-mentioned viewpoint. When water is used, an additive that reduces the surface tension of water and increases the surface activity may be added in a small proportion. It is preferable that this additive does not dissolve the resist film on the wafer and has a negligible effect on the optical coating on the lower surface of the lens. The water used is preferably distilled water.

After the above exposure, post-exposure bake (PEB) is performed, and the exposed portion of the resist film is exposed to the acid generated from [B] acid generator, [B'] other acid generator or the like [A]. It is preferable to promote the dissociation of the acid-dissociable group of the polymer or the like. This PEB can increase the difference in solubility in the developing solution between the exposed portion and the unexposed portion. As a minimum of PEB temperature, 50 °C is preferred and 80 °C is more preferred. On the other hand, the upper limit of the temperature is preferably 180°C, more preferably 130°C. The lower limit of the PEB time is preferably 5 seconds, more preferably 10 seconds. On the other hand, the upper limit of the above time is preferably 600 seconds, more preferably 300 seconds.

According to the resist pattern forming method, since the radiation-sensitive resin composition described above is used, shrinkage of the resist film during PEB can be suppressed.

[Development process]
In this step, the resist film exposed in the exposure step is developed. Thereby, a predetermined resist pattern can be formed. After the development, it is general to wash with a rinse liquid such as water or rucor and then dry. The developing method in the developing step may be alkali development or organic solvent development. In the case of organic solvent development, since the exposed portion forms a resist pattern, it is possible to effectively exhibit the excellent film shrinkage suppression property of the radiation-sensitive resin composition.

In the case of alkaline development, a developer used for development includes, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-. Propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, 1 And an aqueous alkaline solution in which at least one alkaline compound such as 5-diazabicyclo-[4.3.0]-5-nonene is dissolved. Among these, TMAH aqueous solution is preferable, and 2.38 mass% TMAH aqueous solution is more preferable.

In the case of organic solvent development, examples of the developer include hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, organic solvents such as alcohol solvents, solvents containing the above organic solvents, and the like. Examples of the organic solvent include one or more of the solvents exemplified as the above-mentioned [E] solvent. Among these, ester solvents and ketone solvents are preferable. As the ester solvent, an acetic acid ester solvent is preferable, and n-butyl acetate is more preferable. As the ketone solvent, a chain ketone is preferable, and 2-heptanone is more preferable. The lower limit of the content of the organic solvent in the developer is preferably 80% by mass, more preferably 90% by mass, further preferably 95% by mass, particularly preferably 99% by mass. Examples of components other than the organic solvent in the developing solution include water and silicone oil.

Examples of the developing method include a method of dipping the substrate in a tank filled with the developing solution for a certain period of time (dip method), and a method of raising the developing solution on the surface of the substrate by surface tension and standing for a certain period of time (paddle method). ), a method of spraying the developing solution on the surface of the substrate (spray method), a method of continuously discharging the developing solution while scanning the developing solution discharge nozzle at a constant speed on the substrate rotating at a constant speed (dynamic dispensing method), etc. Is mentioned.

<Acid generator>
The acid generator is —SO ₃ ^— , a first carbon atom, a second carbon atom, two or more electron-withdrawing groups represented by the formula (A), and the electron-withdrawing group. Having a monovalent anion containing an organic group other than, and a monovalent radiation-sensitive onium cation, the above-SO ₃ ^— and the second carbon atom are bonded to the first carbon atom, and the first carbon atom and the It is composed of a compound in which the organic group and a total of two or more electron withdrawing groups are bonded to one or both of two carbon atoms. Since the acid generator improves the LWR performance, resolution, rectangularity of cross-sectional shape, depth of focus, MEEF performance and film shrinkage suppression property of the radiation-sensitive resin composition, it is used as a component of the radiation-sensitive resin composition. It can be preferably used.

As the above compound, compounds represented by the above formulas (1-1) to (1-3) are preferable. In this case, at least one of R ¹ , R ² and R ^{3 in} the formulas (1-1) to (1-3) is an organic group other than the electron-withdrawing group represented by the formula (A). It is a base.

<Compound>
The acid generator is —SO ₃ ^— , a first carbon atom, a second carbon atom, two or more electron-withdrawing groups represented by the formula (A), and the electron-withdrawing group. Having a monovalent anion containing an organic group other than, and a monovalent radiation-sensitive onium cation, the above-SO ₃ ^— and the second carbon atom are bonded to the first carbon atom, and the first carbon atom and the The organic group and a total of two or more electron withdrawing groups are bonded to one or both of the two carbon atoms. Since the compound has the above-mentioned properties, it can be suitably used as an acid generator of a radiation-sensitive resin composition.

As the compound, compounds represented by the above formulas (1-1) to (1-3) are preferable. In this case, at least one of R ¹ , R ² and R ^{3 in} the formulas (1-1) to (1-3) is an organic group other than the electron-withdrawing group represented by the formula (A). It is a base.

<Method for producing compound>
[First Manufacturing Method]
The first manufacturing method of the compound, -SO ₃ ^- and, the first carbon atom, and a second carbon atom, and two or more electron-withdrawing group represented by the formula (A), the electronic It has a monovalent anion containing an organic group other than an attracting group and a monovalent radiation-sensitive onium cation, and the above-SO ₃ ^— and the second carbon atom are bonded to the first carbon atom, A method for producing a compound in which the organic group and a total of two or more electron-withdrawing groups are bonded to one or both of a carbon atom and a second carbon atom, which comprises an ethylenic carbon-carbon double bond. A sulfite salt is added to the double bond of the unsaturated compound having a pair of carbon atoms and an organic group bonded to one or both of the pair of carbon atoms and a total of two or more electron withdrawing groups. It is characterized by comprising a step of causing an addition reaction. According to the production method, the compound can be produced easily and reliably.

As the compound produced by the production method, compounds represented by the above formulas (1-1) to (1-3) are preferable. In this case, at least one of R ¹ , R ² and R ^{3 in} the formulas (1-1) to (1-3) is an organic group other than the electron-withdrawing group represented by the formula (A). It is a base.

[Second manufacturing method]
The first manufacturing method of the compound, -SO ₃ ^- and, the first carbon atom, and a second carbon atom, and two or more electron-withdrawing group represented by the formula (A), the electronic It has a monovalent anion containing an organic group other than an attracting group and a monovalent radiation-sensitive onium cation, and the above-SO ₃ ^— and the second carbon atom are bonded to the first carbon atom, A method for producing a compound in which the organic group and a total of two or more electron-withdrawing groups are bound to one or both of a carbon atom and a second carbon atom, wherein a halogen atom, a third carbon atom, and A fourth carbon atom, two or more electron-withdrawing groups, and the organic group, wherein the third carbon atom is bound to the halogen atom and the fourth carbon atom to form a third carbon atom and a fourth carbon atom. A step of substituting a dithionite salt for a third carbon atom and a halogen atom of a halogen compound in which the organic group and a total of two or more electron withdrawing groups are bonded to one or both of carbon atoms It is characterized by According to the production method, the compound can be produced easily and reliably.

As the compound produced by the production method, compounds represented by the above formulas (1-1) to (1-3) are preferable. In this case, at least one of R ¹ , R ² and R ^{3 in} the formulas (1-1) to (1-3) is an organic group other than the electron-withdrawing group represented by the formula (A). It is a base.

The acid generator, the compound, and the first and second methods for producing the compound have already been described in the section of [B] acid generator, and thus the description thereof is omitted here.

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples. In addition, each measurement in an Example and a comparative example was performed by the following method.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
For the Mw and Mn of the polymer used in the examples, a GPC column manufactured by Tosoh Corporation (G2000HXL: 2, G3000HXL: 1 and G4000HXL: 1) was used, flow rate: 1.0 mL/min, elution solvent: tetrahydrofuran, Sample concentration: 1.0% by mass, sample injection amount: 100 μL, column temperature: 40° C., detector: measurement was performed by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under the analytical conditions of a differential refractometer. The dispersity (Mw/Mn) was calculated from the measurement results of Mw and Mn.

[ ¹³ C-NMR analysis]
Using "JNM-ECX400" manufactured by JEOL Ltd., deuterated chloroform was used as a measurement solvent, and an analysis for determining the content ratio (mol%) of each structural unit in each polymer was conducted.

<Synthesis of compound>
[Example 1] (Synthesis of compound (Z-1))
In a 300 mL round bottom flask, 3 g (15.4 mmol) of an aldehyde compound represented by the following formula (z-1), 1.02 g (15.4 mmol) of malononitrile, 0.1 g (1.54 mmol) of imidazole, and methylene chloride. 200 mL was added, and the mixture was stirred at room temperature for 5 hours under a nitrogen atmosphere. 100 mL of water was added to the reaction liquid after stirring, and the organic layer was extracted. The obtained organic layer was washed twice with water and then dried over anhydrous sodium sulfate. The solvent was distilled off from the dried reaction solution to obtain 3.73 g (yield 100%) of the compound (z'-1).

Next, 2 g (8.26 mmol) of compound (z'-1), 40 mL of acetonitrile, and 1.72 g (16.5 mmol) of sodium hydrogen sulfite were added to a 300 mL round bottom flask, and the mixture was heated under reflux for 3 hours. The reaction solution after heating under reflux was cooled to room temperature, and then the solvent was distilled off. Subsequently, to this reaction solution were added 2.47 g (8.26 mmol) of triphenylsulfonium chloride, 40 mL of dichloromethane, and 15 mL of water, and the mixture was stirred at room temperature for 3 hours. The organic layer was recovered from the reaction solution after stirring, and the recovered organic layer was washed with water three times. The solvent was distilled off from the washed organic layer, and the residue was further purified by column chromatography to obtain 3.59 g (yield 74%) of compound (Z-1).

[Example 12] (Synthesis of compound (Z-12))
4.26 g (14.8 mmol) of a halogen compound represented by the following formula (z-12), 3.60 g (20.7 mmol) of sodium dithionite, 1.99 g (23.7 mmol) of sodium hydrogencarbonate, 20 mL of acetonitrile, And 20 mL of water were put in a 200 mL eggplant-shaped flask, and the mixture was heated and stirred at 70° C. for 5 hours to carry out sulfinization. Next, after cooling the reaction solution to room temperature, a catalytic amount of sodium (IV) tungstate was added without isolating the sulfinic body, and then 2.86 g (25. 2 mmol) was added dropwise. The reaction solution was stirred for 7 hours, extracted with acetonitrile, and the solvent was distilled off to obtain 2.15 g (yield 55%) of a sodium sulfonate compound (z'-12).

2.15 g (8.14 mmol) of the above sodium sulfonate (z'-12), 2.43 g (8.14 mmol) of triphenylsulfonium chloride, 80 mL of dichloromethane and 80 mL of water were mixed and stirred at room temperature for 7 hours. Next, the organic layer was recovered from the reaction liquid after stirring and washed 5 times with water. The organic layer washed with water was distilled off of the solvent and then purified by column chromatography to obtain 3.08 g (yield 75%) of the compound (Z-12).

[Examples 2 to 11 and 13 to 14] (Synthesis of compounds (Z-2) to (Z-11) and (Z-13) to (Z-14))
By appropriately selecting a precursor and selecting a formulation similar to that of Example 1 or 12, it is represented by the following formulas (Z-2) to (Z-11) or (Z-13) to (Z-14). Was synthesized.

<Synthesis of [A] Polymer and [D] Polymer>
The monomers used for the synthesis of each polymer in each Example and Comparative Example are shown below.

[Synthesis Example 1] Synthesis of polymer (A-1) 9.38 g (50 mol%) of compound (M-1) and 10.62 g (50 mol%) of compound (M-8) were dissolved in 40 g of 2-butanone. Then, a monomer solution was prepared by further dissolving 0.785 g of azobisisobutyronitrile (5 mol% based on all monomers) in the obtained solution. Next, a 200 mL three-necked flask containing 20 g of 2-butanone was heated to 80° C. with stirring under a nitrogen atmosphere, and the above-prepared monomer solution was added dropwise thereto over 3 hours. After completion of dropping, the reaction solution was further heated at 80° C. for 3 hours to carry out a polymerization reaction. After the completion of the polymerization reaction, the reaction solution was cooled to room temperature and then put into 300 g of methanol, and the precipitated solid was separated by filtration. The filtered solid was washed twice with 60 mL of methanol, further filtered, and then dried under reduced pressure at 50° C. for 15 hours to obtain a polymer (A-1) (yield 15.8 g, yield 78). .9%). The Mw of the polymer (A-1) was 6,100, and the Mw/Mn was 1.41. As a result of ¹³ C-NMR analysis, the content ratios of the structural units derived from the compound (M-1) and the compound (M-8) in the polymer (A-1) were 49.8 mol% and 50.2 mol %, respectively. %Met.

[Synthesis Examples 2 to 7] Synthesis of Polymers (A-2) to (A-7) The same operation as in Synthesis Example 1 is performed except that the types and amounts of the monomers shown in Table 1 below are used. Thus, the polymers (A-2) to (A-7) were synthesized.

[Synthesis Example 8] Synthesis of polymer (A-8) Compound (M-15) 45.24 g (50 mol %), compound (M-1) 54.76 g (50 mol %), azobisiso as an initiator 4.58 g of butyronitrile (5 mol% based on all monomers) and 1.14 g of t-dodecyl mercaptan were dissolved in 100 g of propylene glycol monomethyl ether, and then the reaction temperature was kept at 70° C. under a nitrogen atmosphere. For 16 hours. After the completion of the polymerization reaction, the polymerization solution was dropped into 1,000 g of n-hexane for coagulation and purification, 150 g of propylene glycol monomethyl ether was added again to the obtained solid, and further 150 g of methanol, 34 g of triethylamine and 6 g of water were added. In addition, the hydrolysis reaction was carried out for 8 hours while refluxing at the boiling point. After completion of the reaction, the solvent and triethylamine were distilled off under reduced pressure, the obtained solid was dissolved in 150 g of acetone, and then dropped into 2,000 g of water for coagulation, and the produced solid was filtered and filtered at 50° C. for 17 hours. A white powdery polymer (A-8) was obtained by drying (yield 63.8 g, yield 72.3%). The Mw of the polymer (A-8) was 6,400, and the Mw/Mn was 1.72. As a result of ¹³ C-NMR analysis, the content rates of the p-hydroxystyrene unit and the structural unit derived from the compound (M-1) in the polymer (A-8) are 48.8 mol% and 51.2 mol %, respectively. Met.

[Synthesis Example 9] Synthesis of polymer (D-1) 5.16 g (20 mol%) of compound (M-16), 11.46 g (40 mol%) of compound (M-17), and compound (M-18) ) 13.38 g was dissolved in 20 g of 2-butanone, and 1.16 g of azobisisobutyronitrile (5 mol% based on all monomers) was further dissolved in the obtained solution to prepare a monomer solution. .. Next, a 100 mL three-necked flask containing 10 g of 2-butanone was heated to 80° C. with stirring under a nitrogen atmosphere, and the monomer solution was added dropwise thereto over 3 hours. The polymerization reaction was performed by further heating the reaction solution after the dropping for 3 hours at 80°C. After completion of the polymerization reaction, the reaction solution was cooled to room temperature. After the reaction solution was transferred to a separatory funnel, the above reaction solution was uniformly diluted with 45 g of n-hexane, and then 180 g of methanol was added and mixed. Next, 9 g of distilled water was added to this mixed liquid, and the mixture was further stirred and allowed to stand for 30 minutes. Then, the lower layer was recovered from the mixed solution, and the solvent of the recovered lower layer was replaced with propylene glycol monomethyl ether acetate to obtain a propylene glycol monomethyl ether acetate solution containing the polymer (D-1) as a solid content ( Yield 72.0%). The Mw of the polymer (D-1) was 7,300 and Mw/Mn was 2.00. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from the compound (M-16), the compound (M-17), and the compound (M-18) in the polymer (D-1) was 20. It was 0.1 mol%, 38.9 mol%, and 41.0 mol%.

<Preparation of radiation-sensitive resin composition>
The other acid generators [B′], the acid diffusion control agents [C] and the solvents [E] used for the preparation of the radiation-sensitive resin compositions of Examples and Comparative Examples are shown below.

[[B'] other acid generator]
Each structural formula is shown below.

[[C] Acid diffusion control agent]
Each name and structural formula are shown below.
C-1: triphenylsulfonium salicylate C-2: triphenylsulfonium 10-camphorsulfonate C-3: N-(n-undecan-1-ylcarbonyloxyethyl)morpholine

[[E] solvent]
E-1: Propylene glycol monomethyl ether acetate E-2: Cyclohexanone

[[F] uneven distribution promoter]
F-1: γ-butyrolactone

<Performance evaluation during ArF exposure>
[Example 15] (Preparation of radiation-sensitive resin composition (J-1))
(A-1) 100 parts by mass as a polymer, (Z-1) 7.9 parts by mass as a [B1] acid generator, (C-1) 1 as a [C] acid diffusion controller. .6 parts by mass, (D-1) 3 parts by mass as the [D] polymer, (E-1) 2,240 parts by mass and (E-2) 960 parts by mass as the [E] solvent, and [F The radiation-sensitive resin composition (J-1) was prepared by mixing 30 parts by mass of (F-1) as an uneven distribution promoter and filtering the mixture with a membrane filter having a pore size of 0.2 μm.

[Examples 16 to 36 and Comparative Examples 1 and 2] (Preparation of radiation-sensitive resin compositions (J-2) to (J-22) and (CJ-1) to (CJ-2))
Radiation-sensitive resin compositions were prepared in the same manner as in Example 15, except that the components shown in Table 2 below were used. The compounds (Z-1) to (Z-14) were used as the [B1] acid generator.

[Formation of resist pattern by ArF exposure and alkali development (1)]
A spin coater (“CLEAN TRACK ACT12” manufactured by Tokyo Electron Co., Ltd.) is used to coat a composition for forming a lower antireflection film (“ARC66” manufactured by Brewer Science Co., Ltd.) on a surface of a 12-inch silicon wafer at 205° C. By heating for 60 seconds, an antireflection film having an average thickness of 105 nm was formed. Each radiation-sensitive resin composition prepared as described above was applied onto this antireflection film using the above spin coater, and PB was performed at 90° C. for 60 seconds. Then, the wafer coated with the radiation sensitive resin composition was cooled at 23° C. for 30 seconds to form a resist film having an average thickness of 90 nm. Next, an ArF excimer laser immersion exposure apparatus ("NSR-S610C" manufactured by NIKON) was used for this resist film under the optical conditions of NA=1.3 and dipole (Sigma 0.977/0.782). And exposed through a 40 nm line and space (1L1S) mask pattern. After exposure, PEB was performed on the resist film at 90° C. for 60 seconds. Then, the resist film was alkali-developed using a 2.38 mass% TMAH aqueous solution as an alkali developer, washed with water after development, and dried to form a positive resist pattern. At the time of forming this resist pattern, the line width formed through a mask of 1:1 line and space with a target size of 40 nm is defined as the optimum exposure amount, which is the amount of exposure formed in a 1:1 line and space with a line width of 40 nm. did.

[Formation of resist pattern by ArF exposure and organic solvent development (2)]
Negative resist patterns were formed in the same manner as in the above resist pattern formation (1), except that n-butyl acetate was used instead of the TMAH aqueous solution for organic solvent development, and washing with water was not performed. Formed.

The following measurement was performed on the resist pattern to evaluate the performance of each radiation-sensitive resin composition during ArF exposure. A scanning electron microscope (“CG-4100” manufactured by Hitachi High-Technologies Corporation) was used for measuring the length of the resist pattern.

[LWR performance]
Using the scanning electron microscope, the resist pattern was observed from above the pattern, and the line width was measured at a total of 50 points at arbitrary points. A 3-sigma value was obtained from the distribution of the measured values, and this was taken as the LWR performance (nm). The LWR performance is better as the value is smaller. The LWR performance can be evaluated as “good” when it is 4.0 nm or less and “not good” when it exceeds 4.0 nm.

[Resolution]
The dimension of the smallest resist pattern that can be resolved at the optimum exposure dose was measured, and the measurement result was defined as the resolution (nm). The smaller the value, the better the resolution. The resolution can be evaluated as "good" when it is 34 nm or less and "not good" when it exceeds 34 nm.

[Rectangularity of cross-sectional shape]
By observing the cross-sectional shape of the resist pattern resolved at the optimum exposure dose, the line width Lb at the middle of the height direction of the resist pattern and the line width La at the upper part of the resist pattern are measured, and La with respect to Lb is measured. Was defined as the rectangular shape of the cross-sectional shape. The rectangularity of the cross-sectional shape can be evaluated as “good” when 0.9≦La/Lb≦1.1, and “not good” when out of the above range.

[Depth of focus]
In the resist pattern resolved at the optimum exposure dose, the dimension when the focus is changed in the depth direction is observed, and the pattern dimension is within 90% to 110% of the standard with no bridge or residue. Was measured, and the measurement result was used as the depth of focus (nm). The greater the depth of focus, the better. When the depth of focus is 60 nm or more, it can be evaluated as “good”, and when it exceeds 60 nm, it can be evaluated as “not good”.

[MEEF performance]
In the above optimum exposure amount, a resist pattern resolved with 5 kinds of mask sizes (38.0 nm Line/80 nm Pitch, 39.0 nm Line/80 nm Pitch, 40.0 nm Line/80 nm Pitch, 41.0 nm Line/80 nm Pitch, and 42.0 nm Line/80 nm Pitch). Was measured. The measured values obtained by plotting the mask size on the horizontal axis and the line width formed on each mask size on the vertical axis were plotted, and the slope of the approximate straight line calculated by the least-squares method was determined, and this slope was defined as the MEEF performance. The MEEF performance shows that the smaller the value, the better. The MEEF performance can be evaluated as "good" when it is 4.0 or less and "not good" when it is more than 4.0.

<Evaluation of Membrane Shrinkage Inhibition>
A spin coater (“CLEAN TRACK ACT12” manufactured by Tokyo Electron Co., Ltd.) is used to coat a composition for forming a lower antireflection film (“ARC66” manufactured by Brewer Science Co., Ltd.) on a surface of a 12-inch silicon wafer at 205° C. By heating for 60 seconds, an antireflection film having an average thickness of 105 nm was formed. Each of the radiation-sensitive resin compositions prepared as described above was coated on the antireflection film using the spin coater, and PB was performed at 90° C. for 60 seconds. Then, the silicon wafer subjected to PB was cooled at 23° C. for 30 seconds to form a resist film having an average thickness of 90 nm. Next, an ArF excimer laser immersion exposure apparatus ("NSR-S610C" manufactured by NIKON) was used for this resist film, and the entire surface was exposed at 70 mJ, and then the film thickness was measured to obtain the film thickness A before PEB. I asked. Subsequently, PEB was performed on the resist film after the entire surface exposure at 90° C. for 60 seconds, and then the film thickness was measured again to obtain the film thickness B after PEB. From the measurement results, 100×(A−B)/A(%) was determined, and this was defined as the film shrinkage suppression property (%). The smaller the value of the film shrinkage suppression property, the better the film shrinkage suppression property. The film shrinkage suppression property can be evaluated as "good" when it is 14% or less and "not good" when it exceeds 14%.

The results of the performance evaluation of each radiation-sensitive resin composition during ArF exposure and the evaluation results of the film shrinkage suppression property are shown in Table 3 below.

<Performance evaluation during electron beam exposure>
[Example 37] (Preparation of radiation-sensitive resin composition (J-23))
(A-8) 100 parts by mass as a polymer, (Z-1) 20 parts by mass as an acid generator, (C-1) 3.2 parts by mass as an acid diffusion controller. 3 parts by weight of (D-1) as a polymer of [D], and 4,280 parts by weight of (E-1) and 1,830 parts by weight of (E-2) as a solvent of [E] are blended, and the pore size is 0. A radiation-sensitive resin composition (J-23) was prepared by filtering with a 0.2 μm membrane filter.

[Examples 38 to 39 and Comparative Examples 3 to 4] (Radiation-sensitive resin compositions (J-24) to (J-25) and (CJ-3) to (CJ-4))
Each radiation-sensitive resin composition was prepared in the same manner as in Example 37, except that the types and amounts of the components shown in Table 4 below were used.

[Formation of resist pattern by electron beam exposure and alkali development (3)]
Using a spin coater (“CLEAN TRACK ACT8” manufactured by Tokyo Electron Co., Ltd.) on the surface of an 8-inch silicon wafer, each radiation-sensitive resin composition shown in Table 4 was applied, and PB was performed at 90° C. for 60 seconds. .. Then, the silicon wafer was cooled at 23° C. for 30 seconds to form a resist film having an average thickness of 50 nm. Next, this resist film was irradiated with an electron beam using a simple electron beam drawing apparatus (“HL800D” manufactured by Hitachi, Ltd., output: 50 KeV, current density: 5.0 A/cm ² ). After the irradiation, PEB was performed on the resist film at 120° C. for 60 seconds. After that, the resist film was developed for 30 seconds at 23° C. using a 2.38 mass% TMAH aqueous solution as an alkaline developing solution, then washed with water and further dried to form a positive resist pattern.

[Formation of resist pattern by electron beam exposure and organic solvent development (4)]
Negative resist patterns were formed in the same manner as in the above resist pattern formation (3), except that n-butyl acetate was used instead of the TMAH aqueous solution for organic solvent development, and washing with water was not performed. Formed.

With respect to the resist pattern formed by the electron beam exposure, LWR performance, resolution, depth of focus, and rectangular cross section were evaluated in the same manner as in the case of using the resist pattern formed by ArF exposure. The evaluation results are shown in Table 5 below. In the case of a resist pattern formed by electron beam exposure, it can be evaluated as “good” when the LWR performance is 5.2 nm or less and “not good” when it exceeds 5.2 nm.

As shown in Table 3 and Table 5, the radiation-sensitive resin compositions of the examples have LWR performance, resolution, rectangular cross-sectional shape, depth of focus, MEEF performance, and film shrinkage when subjected to ArF exposure. All of the suppression properties were good, and when electron beam exposure was performed, all of the LWR performance, resolution, rectangularity of cross-sectional shape, and depth of focus were good. Therefore, it is judged that the radiation-sensitive resin composition is excellent in LWR performance, resolution, rectangularity of sectional shape, depth of focus, MEEF performance, and film shrinkage suppression property. On the other hand, the radiation-sensitive resin composition of Comparative Example was not good in at least a part of the above-mentioned performance. Here, it is generally known that electron beam exposure exhibits the same tendency as in the case of EUV exposure. Therefore, it is presumed that the radiation-sensitive resin compositions of the examples are excellent in LWR performance, resolution, rectangular cross-sectional shape and depth of focus even in the case of EUV exposure.

According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, while exhibiting excellent depth of focus, MEEF performance, and film shrinkage suppression property, LWR is small, resolution is high, and rectangularity of cross-sectional shape is excellent. A resist pattern can be formed. The radiation-sensitive acid generator and compound of the present invention can be suitably used as a component of a radiation-sensitive resin composition. According to the method for producing a compound of the present invention, the above compound can be easily and surely obtained. Therefore, these can be preferably used for manufacturing semiconductor devices, which are expected to be further miniaturized in the future.

Claims (9)

A polymer having a structural unit containing an acid dissociable group,
Containing a radiation-sensitive acid generator,
The radiation-sensitive acid generator is a compound represented by the following formula (1-1), (1-2) or (1-3) a first compound der Ru radiation sensitive resin composition represented by.

(In the formulas (1-1), (1-2) and (1-3), R ¹ , R ² and R ³ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. Or represents a ring structure having 3 to 20 ring members in which two or more of these groups are combined with each other and are formed with a carbon atom or a carbon chain to which they are bonded, and E ⁻ is —SO ₃ ^— . .. A ⁺ is a monovalent radiation-sensitive onium cation, and Y is an electron-withdrawing group represented by the following formula (A).

(In the formula (A), X is each independently a hydrogen atom or a cyano group. n is 0 or 1. * represents a binding site to a moiety other than the electron-withdrawing group. .) The formula (1-1), according to claim 1 wherein at least one of ^R 1, ^{R 2} and ^{R 3} is an organic group other than the electron withdrawing group in (1-2) and (1-3) The radiation-sensitive resin composition of. At least one of R ¹ , R ² and R ^{3 in} the above formulas (1-1), (1-2) and (1-3) is a monovalent group containing at least one of an oxygen atom and a sulfur atom. The radiation-sensitive resin composition according to claim 1 , which is an organic group or a hydrogen atom. The formula (1-1), (1-2) and ^R 1, ^{R 2} and ^{R 3} in claim 1 is a monovalent hydrocarbon group having a hydrogen atom or a C 1-20 in (1-3) The radiation-sensitive resin composition described. A step of applying the radiation-sensitive resin composition according to any one of claims 1 to 4 on one surface side of a substrate;
A step of exposing the resist film obtained by the coating step,
And a step of developing the exposed resist film. A radiation-sensitive acid generator comprising a compound represented by the following formula (1-1), (1-2) or (1-3) .

(In Formulas (1-1), (1-2) and (1-3), R ¹ , R ² and R ³ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. Or represents a ring structure having 3 to 20 ring members in which two or more of these groups are combined with each other and are formed with a carbon atom or a carbon chain to which they are bonded, and E ⁻ is —SO ₃ ^— . A ⁺ is a monovalent radiation-sensitive onium cation, Y is an electron-withdrawing group represented by the following formula (A), provided that at least one of R ¹ , R ² and R ³ is present. One is an organic group other than the electron-withdrawing group represented by the following formula (A).)

(In the formula (A), X is each independently a hydrogen atom or a cyano group. n is 0 or 1. * represents a binding site to a moiety other than the electron-withdrawing group. .) A compound represented by the following formula (1-1), (1-2) or (1-3) .

(In Formulas (1-1), (1-2) and (1-3), R ¹ , R ² and R ³ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. Or represents a ring structure having 3 to 20 ring members in which two or more of these groups are combined with each other and are formed with a carbon atom or a carbon chain to which they are bonded, and E ⁻ is —SO ₃ ^— . A ⁺ is a monovalent radiation-sensitive onium cation, Y is an electron-withdrawing group represented by the following formula (A), provided that at least one of R ¹ , R ² and R ³ is present. One is an organic group other than the electron-withdrawing group represented by the following formula (A).)

(In the formula (A), X is each independently a hydrogen atom or a cyano group. n is 0 or 1. * represents a binding site to a moiety other than the electron-withdrawing group. .) A method for producing a compound represented by the following formula (1-1), (1-2) or (1-3) ,
Ethylenic carbon - a pair of carbon atoms constituting the carbon-carbon double bond, an electron withdrawing group and the electron withdrawing represented by the two following formulas that bind to one or both of the pair of carbon atoms (A) A method for producing a compound, which comprises a step of adding a sulfite to the above-mentioned double bond of an unsaturated compound having an organic group other than an attractive group .

(In Formulas (1-1), (1-2) and (1-3), R ¹ , R ² and R ³ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. Or represents a ring structure having 3 to 20 ring members in which two or more of these groups are combined with each other and are formed with a carbon atom or a carbon chain to which they are bonded, and E ⁻ is —SO ₃ ^— . A ⁺ is a monovalent radiation-sensitive onium cation, Y is an electron-withdrawing group represented by the following formula (A), provided that at least one of R ¹ , R ² and R ³ is present. One is an organic group other than the electron-withdrawing group represented by the following formula (A).)

(In the formula (A), X is each independently a hydrogen atom or a cyano group. n is 0 or 1. * represents a binding site to a moiety other than the electron-withdrawing group. .) A method for producing a compound represented by the following formula (1-1), (1-2) or (1-3) ,
A halogen atom, a third carbon atom, a fourth carbon atom, two electron-withdrawing groups represented by the following formula (A), and an organic group other than this electron-withdrawing group , The halogen atom and the fourth carbon atom are bonded to the third carbon atom, and the organic group and the two electron withdrawing groups are bonded to one or both of the third carbon atom and the fourth carbon atom. The method for producing a compound, comprising the step of substituting the dithionite salt for the third carbon atom and the halogen atom of the halogen compound.

(In Formulas (1-1), (1-2) and (1-3), R ¹ , R ² and R ³ are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. Or represents a ring structure having 3 to 20 ring members in which two or more of these groups are combined with each other and are formed with a carbon atom or a carbon chain to which they are bonded, and E ⁻ is —SO ₃ ^— . A ⁺ is a monovalent radiation-sensitive onium cation, Y is an electron-withdrawing group represented by the following formula (A), provided that at least one of R ¹ , R ² and R ³ is present. One is an organic group other than the electron-withdrawing group represented by the following formula (A).)

(In the formula (A), X is each independently a hydrogen atom or a cyano group. n is 0 or 1. * represents a binding site to a moiety other than the electron-withdrawing group. .)