JP6730641B2 - Method for producing polymer and compound - Google Patents

Description

The present invention relates to a radiation-sensitive resin composition, a resist pattern forming method, a polymer and a compound manufacturing method.

A resist pattern forming method by photolithography is used for forming various electronic devices such as semiconductor devices and liquid crystal devices. In this resist pattern forming method, a radiation sensitive resin composition or the like for forming a resist pattern on a substrate is used. The above radiation-sensitive resin composition produces an acid in an exposed area by irradiation with far ultraviolet rays such as ArF excimer laser light or radiation such as an electron beam, and a developer of the exposed area and the unexposed area by the catalytic action of this acid. And a resist pattern is formed on the substrate.

In addition to excellent resolution, such a radiation-sensitive resin composition is required to have LWR (Line Width Roughness) performance showing line width uniformity and MEEF (Mask Error Enhancement Factor) performance showing mask fidelity. It To meet these demands, various studies have been conducted on the structure of the polymer contained in the radiation-sensitive resin composition, and it is known that the polymer has a lactone structure such as a butyrolactone structure or a norbornane lactone structure. See Kaihei 11-212265, JP 2003-5375 A, and JP 2008-83370 A).

However, at the present time when the resist pattern is miniaturized 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 cannot satisfy these requirements. Not done.

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

The present invention has been made based on the above circumstances, and an object thereof is to provide a radiation-sensitive resin composition having excellent LWR performance and MEEF performance.

（式（１）中、Ｒ^１は、重合性基を含む炭素数２〜２０の１価の基である。Ｒ^２は、置換又は非置換の炭素数１〜２０の１価の炭化水素基である。Ｒ^１及びＲ^２は、互いに合わせられ、Ｒ^１が結合する酸素原子及びＲ^２が結合する炭素原子と共に構成される環員数３〜２０の環構造を形成していてもよい。Ｘは、Ｃ（Ｒ^３）_２又はＮＲ^３である。Ｒ^３は、それぞれ独立して、水素原子、置換若しくは非置換の炭素数１〜２０の１価の炭化水素基、置換若しくは非置換の炭素数１〜２０のオキシ炭化水素基又は置換若しくは非置換の炭素数２〜２０のカルボニルオキシ炭化水素基である。Ｒ^２及び１若しくは２のＲ^３のうちの２つ以上は、互いに合わせられ、これらが結合する炭素原子又は原子鎖と共に構成される環員数３〜２０の環構造を形成していてもよい。） The invention made to solve the above problems is also referred to as a structural unit (hereinafter, also referred to as “structural unit (I)”) derived from a compound represented by the following formula (1) (hereinafter, also referred to as “compound (I)”). Radiation-sensitive resin composition containing a polymer (hereinafter, also referred to as “[A] polymer”) and a radiation-sensitive acid generator (hereinafter, also referred to as “[B] acid generator”) Is.

(In the formula (1), R ¹ is a monovalent group having a polymerizable group and having 2 to 20 carbon atoms. R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. R ¹ and R ² may be combined with each other to form a ring structure having 3 to 20 ring members, which is composed of an oxygen atom to which R ¹ is bonded and a carbon atom to which R ² is bonded. Is C(R ³ ) ₂ or NR ^3. Each R ³ is independently a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon atom. two or more of the .R ² and 1 or 2 of R ³ is a C 1-20 oxy hydrocarbon group or a substituted or unsubstituted carbonyloxy hydrocarbon group having 2 to 20 carbon atoms, are combined with each other, (These may form a ring structure having 3 to 20 ring members, which is formed with a carbon atom or an atom chain to which these are bonded.)

Another invention made to solve the above problems is a step of forming a resist film (hereinafter, also referred to as “resist film forming step”), a step of exposing the resist film (hereinafter, also referred to as “exposure step”) And a step of developing the exposed resist film (hereinafter, also referred to as “developing step”), the resist pattern forming method comprising forming the resist film from the radiation-sensitive resin composition.

（式（１’）中、Ｒ^１は、重合性基を含む炭素数２〜２０の１価の基である。Ｒ^２は、置換又は非置換の炭素数１〜２０の１価の炭化水素基である。Ｒ^１及びＲ^２は、互いに合わせられ、Ｒ^１が結合する酸素原子及びＲ^２が結合する炭素原子と共に構成される環員数３〜２０の環構造を形成していてもよい。Ｘ’は、ＣＲ^３又はＮである。Ｒ^３は、置換若しくは非置換の炭素数１〜２０の１価の炭化水素基又は置換若しくは非置換の１価のオキシ炭化水素基である。Ｒ^４は、置換若しくは非置換の炭素数１〜２０の１価の炭化水素基又は置換若しくは非置換の炭素数１〜２０の１価のオキシ炭化水素基である。Ｒ^２、Ｒ^３及びＲ^４のうちの２つ以上は、互いに合わせられ、これらが結合する炭素原子又は原子鎖と共に構成される環員数３〜２０の環構造を形成していてもよい。） Yet another invention made to solve the above problems is a polymer having a structural unit derived from a compound represented by the following formula (1′).

(Wherein (1 '), ^{R 1} is a monovalent group having 2 to 20 carbon atoms containing a polymerizable group .R ² is a substituted or unsubstituted monovalent hydrocarbon having 1 to 20 carbon atoms R ¹ and R ² may be combined with each other to form a ring structure having 3 to 20 ring members, which is composed of an oxygen atom to which R ¹ is bonded and a carbon atom to which R ² is bonded. X 'is .R ³ is CR ³ or N is a monovalent hydrocarbon group or a substituted or unsubstituted monovalent oxy hydrocarbon group substituted or unsubstituted C 1 to 20 .R ⁴ Is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms or a substituted or unsubstituted monovalent oxyhydrocarbon group having 1 to 20 carbon atoms, of R ² , R ³ and R ⁴ . Two or more of them may be combined with each other to form a ring structure having 3 to 20 ring members which is configured with a carbon atom or an atom chain to which they are bonded.)

（式（ａ）、（ｂ）及び（１’−ａ）中、Ｒ^１’は、重合性基を含む炭素数２〜１９の１価の基である。Ｒ^２は、置換又は非置換の炭素数１〜２０の１価の炭化水素基である。Ｒ^１及びＲ^２は、互いに合わせられ、Ｒ^１が結合する酸素原子及びＲ^２が結合する炭素原子と共に構成される環員数３〜２０の環構造を形成していてもよい。Ｘ’は、ＣＲ^３又はＮである。Ｒ^３は、置換若しくは非置換の炭素数１〜２０の１価の炭化水素基又は置換若しくは非置換の炭素数１〜２０の１価のオキシ炭化水素基である。Ｒ^４は、置換若しくは非置換の炭素数１〜２０の１価の炭化水素基又は置換若しくは非置換の炭素数１〜２０の１価のオキシ炭化水素基である。Ｒ^２、Ｒ^３及びＲ^４のうちの２つ以上は、互いに合わせられ、これらが結合する炭素原子又は原子鎖と共に構成される環員数３〜２０の環構造を形成していてもよい。Ｚは、−ＣＯ−又は−ＳＯ_２−である。Ｙは、ハロゲン原子である。） Still another invention made to solve the above-mentioned problems is a dehydrohalogenation condensation of a compound represented by the following formula (a) and an acid halide represented by the following formula (b) in the presence of a base. A method for producing a compound represented by the following formula (1′-a), which comprises a step of reacting.

(In formulas (a), (b) and (1′-a), R ^1′ is a monovalent group having a polymerizable group and having 2 to 19 carbon atoms. R ² is a substituted or unsubstituted group. It is a monovalent hydrocarbon group having 1 to 20 carbon atoms, R ¹ and R ² are combined with each other, and the number of ring members is 3 to 20 which is configured with an oxygen atom to which R ¹ is bonded and a carbon atom to which R ² is bonded. X′ is CR ³ or N. R ³ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms or a substituted or unsubstituted carbon. A monovalent oxyhydrocarbon group having 1 to 20. R ⁴ represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms; Two or more of R ² , R ³ and R ⁴ are combined with each other to form a ring structure having 3 to 20 ring members, which is configured with a carbon atom or an atom chain to which they are bonded. May be formed, Z is —CO— or —SO ₂ —, and Y is a halogen atom.)

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 straight chain hydrocarbon group and a branched hydrocarbon group. "Alicyclic hydrocarbon group" means a hydrocarbon group containing only an alicyclic structure as a ring structure and not containing an aromatic ring structure, a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic group. Includes both hydrocarbon groups. However, the structure does not have to be composed only of 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 the aromatic ring structure, and may partially include a chain structure or an alicyclic structure.
Further, the “organic group” refers to a group containing at least one carbon atom.

According to the radiation-sensitive resin composition and the method for forming a resist pattern of the present invention, since the polymer [A] has rigidity due to a specific structure, a resist pattern having a small LWR while exhibiting excellent MEEF performance. Can be formed. The polymer of the present invention can be suitably used as a polymer component of the radiation sensitive resin composition. According to the method for producing a compound of the present invention, a compound that gives the polymer can be easily produced with high yield. Therefore, these can be suitably used for manufacturing semiconductor devices and the like, 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 is a polymer having a fluorine atom content rate (mass%) larger than that of a [C] acid diffusion controller and a [D][A] polymer as suitable components (hereinafter, referred to as “[D] polymer”). (Also referred to as “combination”) and [E] solvent, and may contain other optional components 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 the structural unit (I). When the polymer [A] has the structural unit (I), the radiation-sensitive resin composition has excellent LWR performance and MEEF performance. Although the reason why the radiation-sensitive resin composition has the above-mentioned configuration to exert the above-mentioned effect is not always clear, for example, due to the structure of —O—C=X having rigidity by conjugation, [A ] The polymer has higher rigidity.

The polymer [A] contains, in addition to the structural unit (I), at least one selected from the group consisting of a structural unit (II) containing an acid-labile group, a lactone structure, a cyclic carbonate structure and a sultone structure. It may have a structural unit (IV) containing a unit (III) and a polar group, and may have other structural units other than the above structural units (I) to (IV).
Hereinafter, each structural unit will be described.

[Structural unit (I)]
The structural unit (I) is a structural unit derived from the compound (I). The compound (I) is represented by the following formula (1).

In the above formula (1), R ¹ is a monovalent group having 2 to 20 carbon atoms and containing a polymerizable group. R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. R ¹ and R ² may be combined with each other to form a ring structure having 3 to 20 ring members, which is composed of an oxygen atom to which R ¹ is bonded and a carbon atom to which R ² is bonded. X is C(R ³ ) ₂ or NR ³ . R ³ is each independently a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted oxyhydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted Is a carbonyloxy hydrocarbon group having 2 to 20 carbon atoms. Two or more of R ² and R ³ of 1 or 2 may be combined with each other to form a ring structure having 3 to 20 ring members which is configured with a carbon atom or an atom chain to which they are bonded.

The structural unit (I) is considered to have the structure of the following formula (I) when, for example, R ¹ is a methacryloyl group and —C═X— in the compound (I) does not undergo a polymerization reaction. Since -C=X- is conjugated with the structure of -OC-X-, the polymerization reactivity is low.

Examples of the polymerizable group contained in the R ¹ group include a carbon-carbon double bond-containing group such as a vinyl group, a propenyl group and a butadienyl group, a carbon-carbon triple bond-containing group such as an ethynyl group and a propargyl group. To be Among these, a carbon-carbon double bond-containing group is preferable, and a vinyl group and a propenyl group are more preferable.

Examples of the group represented by R ¹ include groups represented by the following formulas (2-1) to (2-4).

In the above formulas (2-1) to (2-4), L is a single bond or a divalent organic group having 1 to 20 carbon atoms. * Indicates a site bonded to the oxygen atom of the above formula (1).
In the above formula (2-1), R ⁵ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
In the above formula (2-2), R ⁶ is a hydrogen atom or a methyl group. R ⁷ , R ⁸ and R ⁹ are each independently a hydrogen atom, a halogen atom, a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms. Two or more of one or more of R ⁷ and R ⁸ and R ⁹ may be combined with each other to form a ring structure having 3 to 20 ring members which is configured with the carbon atom to which they are bonded. a is an integer of 1 to 4. When a is 2 or more, a plurality of R ⁷ may be the same or different, and a plurality of R ⁸ may be the same or different.
In the above formula (2-3), R ¹⁰ is a hydrogen atom or a methyl group.
In the formula (2-4), R ¹¹ is a hydrogen atom or a methyl group.

Examples of the divalent organic group having 1 to 20 carbon atoms represented by L include a divalent chain hydrocarbon group having 1 to 20 carbon atoms and a divalent alicyclic hydrocarbon having 3 to 20 carbon atoms. A group, a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a group (h) containing a divalent hetero atom-containing group at the carbon-carbon or bond side end of these hydrocarbon groups, Examples thereof include a hydrogen group and a group obtained by substituting a part or all of the hydrogen atoms contained in the group (h) with a monovalent hetero atom-containing group.

Examples of the divalent chain hydrocarbon group having 1 to 20 carbon atoms include methanediyl group, ethanediyl group, n-propanediyl group, i-propanediyl group, n-butanediyl group, i-butanediyl group, sec-butanediyl group. Group, alkanediyl group such as t-butanediyl group;
Alkenediyl groups such as ethenediyl group, propenediyl group, butenediyl group;
Examples include alkynediyl groups such as ethynediyl group, propynediyl group and butynediyl group.

Examples of the divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include monocyclic cycloalkanediyl groups such as cyclopropanediyl group, cyclobutanediyl group, cyclopentanediyl group and cyclohexanediyl group;
A monocyclic cycloalkenediyl group such as a cyclopropenediyl group, a cyclobutenediyl group, a cyclopentenediyl group or a cyclohexenediyl group;
A polycyclic cycloalkanediyl group such as a norbornanediyl group, an adamantanediyl group, a tricyclodecanediyl group, a tetracyclododecanediyl group;
Examples thereof include polycyclic cycloalkenediyl groups such as norbornenediyl group, tricyclodecenediyl group and tetracyclododecenediyl group.

Examples of the divalent aromatic hydrocarbon group having 6 to 20 carbon atoms include arenediyl groups such as benzenediyl group, toluenediyl group and naphthalenediyl group;
Examples thereof include arenediylalkanediyl groups such as benzenediylmethanediyl group and naphthalenediylmethanediyl group.

As the bivalent hetero atom-containing group, for example -O -, - CO -, - CO-O -, - S -, - CS -, - SO 2 -, - NR'- carbon atoms represented by 1 And a divalent group of 10 to 10, a group in which two or more of these are combined, and the like. R'is a hydrogen atom or a monovalent organic group.

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). ..

As the above L, a single bond and an organic group having 4 or less carbon atoms are preferable from the viewpoint of further increasing the rigidity of the polymer [A].

From the viewpoint of copolymerizability of compound (I), R ⁵ is preferably a hydrogen atom or a methyl group, more preferably a methyl group.

From the viewpoint of the copolymerizability of compound (I), R ⁶ is preferably a hydrogen atom.

The monovalent organic group having 1 to 20 carbon atoms represented by R ⁷ , R ⁸ and R ⁹ is, for example, a group obtained by adding one hydrogen atom to those exemplified as the divalent organic group of L above. Etc.

From the viewpoint of further enhancing the rigidity described above, R ⁷ and R ⁸ are preferably hydrogen atoms and monovalent organic groups, and more preferably hydrogen atoms.

From the viewpoint of further enhancing the rigidity described above, R ⁹ is preferably a hydrogen atom or a monovalent organic group, more preferably an alkyl group, and even more preferably a methyl group.

Examples of the ring structure having 3 to 20 ring members, in which two or more of one or more of R ⁷ and R ⁸ and R ⁹ are combined with each other and are bonded to the carbon atom, are, for example, cyclopropane structure and cyclobutane. Alicyclic structure such as structure, cyclopentane structure, cyclohexane structure, norbornane structure, adamantane structure;
Examples thereof include aliphatic heterocyclic structures such as oxacyclopentane structure and azacyclopentane structure.

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

From the viewpoint of the copolymerizability of compound (I), R ¹⁰ is preferably a hydrogen atom.

From the viewpoint of the copolymerizability of compound (I), R ¹¹ is preferably a hydrogen atom.

Examples of the ring structure having 3 to 20 ring members, in which R ¹ and R ² are combined with each other and an oxygen atom to which R ¹ is bonded and a carbon atom to which R ² is bonded are, for example, an oxacyclopentane structure, an oxacyclohexane structure and the like. An oxacycloalkane structure of
Lactone structures such as a butyrolactone structure, a valerolactone structure, a mevalonic lactone structure, and a norbornane lactone structure are included.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ² and R ³ include monovalent chain hydrocarbon groups having 1 to 20 carbon atoms and monovalent hydrocarbon groups having 3 to 20 carbon atoms. Examples thereof include an alicyclic hydrocarbon group and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, an alkyl group such as t-butyl 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 having 3 to 20 carbon atoms include monocyclic cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group and cyclooctyl group;
Polycyclic cycloalkyl groups such as norbornyl group, adamantyl group, tricyclodecyl group, tetracyclododecyl group;
A monocyclic cycloalkenyl group such as a cyclobutenyl group, a cyclopentenyl group or a cyclohexenyl group;
Examples thereof include polycyclic cycloalkenyl groups such as norbornenyl group, tricyclodecenyl group, and tetracyclododecenyl group.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group and anthryl group;
Examples thereof include aralkyl groups such as benzyl group, phenethyl group, phenylpropyl group, and naphthylmethyl group.

Examples of the monovalent oxyhydrocarbon group having 1 to 20 carbon atoms represented by R ³ include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, alkoxy groups such as sec-butoxy group and t-butoxy group;
Alkenyloxy groups such as ethenyloxy group, propenyloxy group, butenyloxy group;
Oxy chain hydrocarbon group such as alkynyloxy group such as ethynyloxy group, propynyloxy group and butynyloxy group,
Cycloalkyloxy groups such as cyclopropyloxy group, cyclobutyloxy group, cyclopentyloxy group, cyclohexyloxy group, cyclooctyloxy group, norbornyloxy group, adamantyloxy group, tricyclodecyloxy group and tetracyclododecyloxy group ;
Cycloaliphatic carbonization such as cycloalkenyloxy group such as cyclobutenyloxy group, cyclopentenyloxy group, cyclohexenyloxy group, norbornenyloxy group, tricyclodecenyloxy group and tetracyclododecenyl group Hydrogen radical,
Aryloxy groups such as phenoxy group, tolyloxy group, xylyloxy group, naphthyloxy group, anthryloxy group;
Examples thereof include an oxyaromatic hydrocarbon group such as an aralkyloxy group such as a benzyloxy group, a phenethyloxy group, a phenylpropoxy group, and a naphthylmethoxy group.

Examples of the C 2-20 monovalent carbonyloxy hydrocarbon group represented by R ³ include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonyl group, and an n-butoxycarbonyl group. An alkoxycarbonyl group such as i-butoxycarbonyl group, sec-butoxycarbonyl group and t-butoxycarbonyl group;
Alkenyloxycarbonyl groups such as ethenyloxycarbonyl group, propenyloxycarbonyl group, butenyloxycarbonyl group;
Carbonyloxy chain hydrocarbon group such as alkynyloxycarbonyl group such as ethynyloxycarbonyl group, propynyloxycarbonyl group and butynyloxycarbonyl group,
Cyclopropyloxycarbonyl group, cyclobutyloxycarbonyl group, cyclopentyloxycarbonyl group, cyclohexyloxycarbonyl group, cyclooctyloxycarbonyl group, norbornyloxycarbonyl group, adamantyloxycarbonyl group, tricyclodecyloxycarbonyl group, tetracyclododecyl A cycloalkyloxycarbonyl group such as an oxycarbonyl group;
Cycloalkenyloxycarbonyl groups such as cyclobutenyloxycarbonyl group, cyclopentenyloxycarbonyl group, cyclohexenyloxycarbonyl group, norbornenyloxycarbonyl group, tricyclodecenyloxycarbonyl group and tetracyclododecenylcarbonyl group Carbonyloxy alicyclic hydrocarbon groups such as
Aryloxycarbonyl groups such as phenoxycarbonyl group, tolyloxycarbonyl group, xylyloxycarbonyl group, naphthyloxycarbonyl group, anthryloxycarbonyl group;
Examples thereof include carbonyloxy aromatic hydrocarbon groups such as aralkyloxycarbonyl groups such as benzyloxycarbonyl group, phenethyloxycarbonyl group, phenylpropoxycarbonyl group and naphthylmethoxycarbonyl group.

Hydrocarbon groups of R ² and R ^3, examples of the substituent group of the oxy hydrocarbon group and carbonyloxy hydrocarbon groups of R ³ of said R ^3, for example, a fluorine atom, a chlorine atom, a bromine atom, such as iodine atom Examples thereof include a halogen atom, a hydroxy group, a carboxy group, an amino group, a cyano group, a nitro group, an alkoxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, an acyl group and an acyloxy group.

As R ² , a chain hydrocarbon group is preferable, an alkyl group is more preferable, and a methyl group is further preferable.

As R ³ , an oxyhydrocarbon group is preferable, an oxy chain hydrocarbon group is more preferable, and an alkoxy group is further preferable.

Examples of the ring structure having 3 to 20 ring members in which R ¹ and R ² are combined with each other and an oxygen atom to which R ¹ is bonded and a carbon atom to which R ² is bonded are, for example, an oxacyclopentane structure, an oxacyclohexane structure, An oxacycloalkane structure such as an oxacycloheptane structure;
Oxacycloalkene structures such as oxacyclopentene structure, oxacyclohexene structure, oxacycloheptene structure;
Lactone structures such as a butyrolactone structure, a valerolactone structure, a mevalonic lactone structure, and a norbornane lactone structure are included.
Of these, the lactone structure is preferable.

Examples of the ring structure having 3 to 20 ring members, which is formed by combining R ² and R ³ with each other and combining them with an atom chain, include, for example, oxocyclopentene structure, oxocyclohexene structure, oxocycloheptene structure, and other oxocycloalkene structures. Construction;
Lactone structures such as butyrolactone structure, valerolactone structure, mevalonic lactone structure, norbornane lactone structure;
And so on.

Examples of the ring structure having 3 to 20 ring members, which is formed by R ^{3 of the} above 2 being combined with each other and a carbon atom to which these are bonded, include, for example, an oxocycloalkane structure such as an oxocyclopentane structure, an oxocyclohexane structure, and an oxocycloheptane structure. ;
Lactone structures such as a butyrolactone structure, a valerolactone structure, a mevalonic lactone structure, and a norbornane lactone structure are included.
Of these, the lactone structure is preferable.

The ring structure is preferably formed by R ^{3 of} 2 above.

As X above, CR ³ is preferable.

As the compound (I), a compound represented by the following formula (1′) (hereinafter, also referred to as “compound (I′)”, and a structural unit derived from the compound (I′) is also referred to as “structural unit (I′)”. Preferred). In the radiation-sensitive resin composition, by using the compound (I′) as the compound (I), the rigidity of the [A] polymer is increased by the conjugated structure of —O—C═X′—C(═O)—. Is higher, the LWR performance and the MEEF performance can be further improved.

In the above formula (1′), X′ is CR ³ or N. R ⁴ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms or a substituted or unsubstituted monovalent oxyhydrocarbon group having 1 to 20 carbon atoms. R ¹ , R ² and R ³ have the same meaning as in the above formula (1). Two or more of R ² , R ³ and R ⁴ may be combined with each other to form a ring structure having 3 to 20 ring members which is configured with a carbon atom or an atom chain to which they are bonded.

Examples of the substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms and the substituted or unsubstituted monovalent oxyhydrocarbon group having 1 to 20 carbon atoms represented by R ⁴ include the above R ³ The same groups as those exemplified above can be mentioned.

As R ⁴ , an oxyhydrocarbon group is preferable, an oxy chain hydrocarbon group is more preferable, and an alkoxy group is further preferable.

Examples of the ring structure having 3 to 20 ring members, which is formed by combining R ² and R ⁴ with each other and combining them with an atom chain, include cycloalkene structures such as cyclopentene structure, cyclohexene structure, and cycloheptene structure.

Examples of the ring structure having 3 to 20 ring members, which is formed by combining R ³ and R ⁴ with each other and combining them with an atom chain, include, for example, butyrolactone structure, valerolactone structure, mevalonic lactone structure and norbornane lactone structure. Lactone structure;
Examples thereof include a cycloketone structure such as a cyclopentanone structure, a cyclohexanone structure, a cycloheptanone structure, a cyclopentenone structure, and a cyclohexenone structure.
Of these, the lactone structure is preferable.

As the X ', CR ³ are preferred.

Examples of the compound (I) include compounds represented by the following formulas (i-1) to (i-5) (hereinafter, also referred to as “compounds (I-1) to (I-5)”) and the like. To be

In the above formula (i-1), R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. X is C(R ³ ) ₂ or NR ³ . R ³ is each independently a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted oxyhydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted Is a carbonyloxy hydrocarbon group having 2 to 20 carbon atoms. Two or more of R ² and R ³ of 1 or 2 may be combined with each other to form a ring structure having 3 to 20 ring members which is configured with a carbon atom or an atom chain to which they are bonded. R ⁵ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. L is a single bond or a divalent organic group having 1 to 20 carbon atoms.

In the above formula (i-2), R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. X is C(R ³ ) ₂ or NR ³ . R ³ is each independently a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted oxyhydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted Is a carbonyloxy hydrocarbon group having 2 to 20 carbon atoms. Two or more of R ² and R ³ of 1 or 2 may be combined with each other to form a ring structure having 3 to 20 ring members which is configured with a carbon atom or an atom chain to which they are bonded. R ⁶ is a hydrogen atom or a methyl group. R ⁷ , R ⁸ and R ⁹ are each independently a hydrogen atom, a halogen atom, a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms. Two or more of one or more of R ⁷ and R ⁸ and R ⁹ may be combined with each other to form a ring structure having 3 to 20 ring members which is configured with the carbon atom to which they are bonded. a is an integer of 1 to 4. When a is 2 or more, a plurality of R ⁷ may be the same or different, and a plurality of R ⁸ may be the same or different. L is a single bond or a divalent organic group having 1 to 20 carbon atoms.

In the above formula (i-3), R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. X is C(R ³ ) ₂ or NR ³ . R ³ is each independently a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted oxyhydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted Is a carbonyloxy hydrocarbon group having 2 to 20 carbon atoms. Two or more of R ² and R ³ of 1 or 2 may be combined with each other to form a ring structure having 3 to 20 ring members which is configured with a carbon atom or an atom chain to which they are bonded. R ¹⁰ is a hydrogen atom or a methyl group. L is a single bond or a divalent organic group having 1 to 20 carbon atoms.

In the above formula (i-4), R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. X is C(R ³ ) ₂ or NR ³ . R ³ is each independently a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted oxyhydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted Is a carbonyloxy hydrocarbon group having 2 to 20 carbon atoms. Two or more of R ² and R ³ of 1 or 2 may be combined with each other to form a ring structure having 3 to 20 ring members which is configured with a carbon atom or an atom chain to which they are bonded. R ¹¹ is a hydrogen atom or a methyl group. L is a single bond or a divalent organic group having 1 to 20 carbon atoms.

In the above formula (i-5), X is C(R ³ ) ₂ or NR ³ . R ³ is each independently a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted oxyhydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted Is a carbonyloxy hydrocarbon group having 2 to 20 carbon atoms. When X is C (R ³⁾ _2, 2 of R ³ may be combined together, may form a ring structure composed of ring members 3 to 20 together with the carbon atoms to which they are attached. R ^6′ is a hydrogen atom or a methyl group. R ^7′ and R ^8′ are each independently a hydrogen atom, a halogen atom, a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms. Two or more of one or a plurality of R ^7′ and R ^8′ may be combined with each other to form a ring structure having 3 to 20 ring members which is configured with the carbon atom to which they are bonded. a′ is an integer of 1 to 4. When a'is 2 or more, plural R ⁷ 's may be the same or different, and plural R ⁸ 's may be the same or different.

From the viewpoint of the copolymerizability of the compound (i-5), R ^6′ is preferably a hydrogen atom.

Examples of the C 1-20 monovalent organic group represented by R ^7′ and R ^8′ include those exemplified as the C 1-20 divalent organic group represented by L above. Examples thereof include groups to which individual hydrogen atoms have been added.

As R ^7′ and R ^8′ , a hydrogen atom is preferable from the viewpoint of further enhancing the rigidity described above.

Examples of the ring structure having 3 to 20 ring members in which two or more of the above-mentioned one or more R ^7′ and R ^8′ are combined with each other and combined with the carbon atom to which they are bonded include, for example, the above formula (i-2 The same ring structure as the ring structure exemplified as the ring structure which may be formed by R ⁷ , R ⁸ and R ^{9 in the} above.

As a ^′ , 1 and 2 are preferable, and 1 is more preferable.

As the compound (I), compounds represented by the following formulas (i-1-1) to (i-1-6) are preferable as the compound (I-1), and the following formula (i-2) is represented as the compound (I-2). The compounds represented by i-2-1) to (i-2-3) are preferable, and the compounds represented by the following formulas (i-3-1 and (i-3-2) as the compound (I-3) The compound (I-4) is preferably a compound represented by the following formulas (i-4-1) and (i-4-2), and the compound (I-5) is a compound represented by the following formula (i-5-1). ) And (i-5-2) are preferred.

In the formulas (i-1-1) to (i-1-6), R ⁵ has the same meaning as in the formula (i-1).
In the above formulas (i-2-1) to (i-2-3), R ⁶ has the same meaning as the above formula (i-2).
In the above formulas (i-3-1) and (i-3-2), R ¹⁰ has the same meaning as in the above formula (i-3).
In the formulas (i-4-1) and (i-4-2), R ¹¹ has the same meaning as in the formula (i-4).
In the above formulas (i-5-1) and (i-5-2), R ^6′ has the same ^{meaning as} in the above formula (i-5).

When the compound (I) is, for example, a compound represented by the following formula (1′-a) (hereinafter, also referred to as compound (I′-a)), the compound (I) is represented by the following scheme. , A compound represented by the following formula (a) (hereinafter, also referred to as compound (a)) and a compound represented by the following formula (b) (hereinafter, also referred to as compound (b)) with potassium carbonate, 1 , 4-diazabicyclo[2.2.2]octane and the like in the presence of a base and the like in a solvent such as acetonitrile and the like, and can be produced by a dehydrohalogenation condensation reaction.

In the formulas (a), (b) and (1′-a), R ^1′ is a monovalent group having 2 to 19 carbon atoms and containing a polymerizable group. R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms. R ¹ and R ² may be combined with each other to form a ring structure having 3 to 20 ring members, which is composed of an oxygen atom to which R ¹ is bonded and a carbon atom to which R ² is bonded. X′ is CR ³ or N. R ³ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms or a substituted or unsubstituted monovalent oxyhydrocarbon group having 1 to 20 carbon atoms. R ⁴ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms or a substituted or unsubstituted monovalent oxyhydrocarbon group having 1 to 20 carbon atoms. Two or more of R ² , R ³ and R ⁴ may be combined with each other to form a ring structure having 3 to 20 ring members which is configured with a carbon atom or an atom chain to which they are bonded. Z is, -CO- or -SO ₂ - is. Y is a halogen atom.

According to the above production method, compound (I) can be produced simply and in good yield.

Examples of the halogen atom represented by Y include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Of these, a chlorine atom is preferred from the viewpoint of ease of synthesis of compound (I).

According to the above production method, the compound (I) other than the above compound (I′-a) can be synthesized in the same manner as the above compound (I′-a).

The lower limit of the content ratio of the structural unit (I) in the polymer [A] is preferably 5 mol%, more preferably 10 mol%, and 15 mol% with respect to all the structural units constituting the polymer [A]. Is more preferable, and 30 mol% is particularly preferable. The upper limit of the content ratio is preferably 90 mol%, more preferably 80 mol%, further preferably 70 mol%, particularly preferably 60 mol%. By setting the content ratio of the structural unit (I) within the above range, the LWR performance and MEEF performance of the radiation-sensitive resin composition can be further improved.

[Structural unit (II)]
The structural unit (II) is a structural unit containing an acid dissociable group (provided that the structural unit (I) is excluded). The "acid-dissociable group" means a group that substitutes a hydrogen atom of a carboxy group or a phenolic hydroxyl group and is dissociated by the action of an acid. When the polymer [A] has the structural unit (II), the sensitivity of the radiation-sensitive resin composition can be further increased, and as a result, the LWR performance and the MEEF performance can be further improved.

As the structural unit (II), for example, a structural unit represented by the following formula (3-1) (hereinafter, also referred to as “structural unit (II-1)”), a structure represented by the following formula (3-2) A unit (henceforth "structural unit (II-2)") etc. are mentioned.

In the above formula (3-1), R ¹² is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹³ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R<^14> and R< ¹⁵ > are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or 3 to 20 carbon atoms in which these groups are combined with each other and are combined with the carbon atom to which they are bonded. Represents the alicyclic structure of.
In the above formula (3-2), R ¹⁶ is a hydrogen atom or a methyl group. L ¹ is a single bond, —CCOO— or —CONH—. R ¹⁷ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ¹⁸ and R ¹⁹ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent oxyhydrocarbon group having 1 to 20 carbon atoms.

From the viewpoint of the copolymerizability of the monomer giving the structural unit (II), R ¹² is preferably a hydrogen atom and a methyl group, and more preferably a methyl group.
From the viewpoint of the copolymerizability of the monomer giving the structural unit (II), R ¹⁶ is preferably a hydrogen atom.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^{13 to} R ¹⁵ and R ^{17 to} R ¹⁹ are exemplified as the hydrocarbon groups of R ² and R ³ in the above formula (1). The same groups as those mentioned above can be mentioned.

Examples of the alicyclic structure having 3 to 20 carbon atoms, which is formed by combining these groups in the above formula (3-1) with each other and combining them with each other, include a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, and cyclohexane. Structures, cycloheptane structures, cyclooctane structures, and other monocyclic cycloalkane structures;
Examples thereof include polycyclic cycloalkane structures such as a norbornane structure, an adamantane structure, a tricyclodecane structure, and a tetracyclododecane structure.

Examples of the monovalent oxyhydrocarbon group having 1 to 20 carbon atoms represented by the above formulas R ¹⁸ and R ¹⁹ include the same groups as those exemplified as the oxyhydrocarbon group for R ³ in the above formula (1). Are listed.

As the structural unit (II-1), structural units represented by the following formulas (3-1-1) to (3-1-5) (hereinafter, “structural units (II-1-1) to (II-1) -5)" is also preferable).
As the structural unit (II-2), a structural unit represented by the following formula (3-2-1) (hereinafter, also referred to as “structural unit (II-2-1)”) is preferable.

In the formulas (3-1-1) to (3-1-5), R ^{12 to} R ¹⁵ have the same meanings as in the formula (3-1). R ^13′ , R ^14′ and R ^15′ are each independently a monovalent chain hydrocarbon group having 1 to 10 carbon atoms. n _p is each independently an integer of 1 to 4.
In the formula (3-2-1), R ^{16 to} R ¹⁹ have the same meaning as in the formula (3-2).

Examples of the structural units (II-1-1) to (II-1-5) include structural units represented by the formulas below.

In the above formula, R ¹² has the same meaning as in the above formula (3-1).

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

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

In the above formula, R ¹⁶ has the same meaning as in the above formula (3-2).

As the structural unit (II-2), a structural unit derived from p-(1-(cyclohexylethoxy)ethoxy)styrene is preferable.

The lower limit of the content of the structural unit (II) is preferably 10 mol%, more preferably 20 mol%, and even more preferably 35 mol% based on all structural units constituting the polymer [A]. The upper limit of the content is preferably 90 mol%, more preferably 80 mol%, and even more preferably 70 mol%. By setting the content ratio of the structural unit (II) in the above range, the sensitivity of the radiation-sensitive resin composition can be further enhanced, and as a result, the LWR performance and the MEEF performance can be further improved.

[Structural unit (III)]
The structural unit (III) is a structural unit containing at least one selected from the group consisting of a lactone structure, a cyclic carbonate structure and a sultone structure (provided that the structural unit (I) is excluded). When the polymer [A] further has the structural unit (III), the solubility in a developing solution can be appropriately adjusted. Further, the adhesion of the resist pattern formed from the radiation-sensitive resin composition to the substrate can be improved. Here, the lactone structure refers to a structure having a ring (lactone ring) containing a group represented by —O—C(O)—. Further, the cyclic carbonate structure refers to a structure having a ring (cyclic carbonate ring) containing a group represented by -OC(O)-O-. The sultone structure refers to a structure having a ring (sultone ring) containing a group represented by -OS(O) _2- .

Examples of the structural unit (III) include structural units represented by the following formula.

In the above formula, R ²⁰ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

From the viewpoint of the copolymerizability of the monomer giving the structural unit (III), R ²⁰ is preferably a hydrogen atom and a methyl group, and more preferably a methyl group.

Among these, as the structural unit (III), a structural unit containing a lactone structure is preferable, a structural unit containing a norbornane lactone structure is more preferable, and a structural unit derived from norbornane lactone-yl(meth)acrylate is further preferable.

When the polymer [A] has the structural unit (III), the lower limit of the content of the structural unit (III) is preferably 5 mol% based on all the structural units constituting the polymer [A]. Mol% is more preferred. The upper limit of the content ratio is preferably 70 mol%, more preferably 40 mol%. When the content of the structural unit (III) is within the above range, the solubility of the polymer [A] in the developing solution can be adjusted more appropriately. Further, the adhesion of the resist pattern formed from the radiation sensitive resin composition to the substrate can be further improved.

[Structural unit (IV)]
A structural unit having the structural unit (IV) and the structural unit (IV) containing a polar group. When the polymer [A] further has the structural unit (IV), the compatibility of the polymer [A] with other components such as the acid generator [B] is improved, and thus the radiation-sensitive resin composition. It is possible to further improve the LWR performance and MEEF performance of the product. Examples of the polar group include a hydroxy group, a carboxy group, an amino group, a sulfonamide group, a cyano group, and a nitro group. Examples of the structural unit (IV) include structural units represented by the formulas below.

In the above formula, R ²¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

When the polymer [A] has the structural unit (IV), the upper limit of the content ratio of the structural unit (IV) is preferably 30 mol% based on all structural units constituting the polymer [A]. Mol% is more preferred.

[Other structural units]
The polymer [A] may have other structural units in addition to the structural units (I) to (IV). When the polymer [A] has other structural units, the upper limit of the content of the other structural units is preferably 20 mol% and more preferably 10 mol%.

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 solids in the radioactive resin composition.

<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 using a radical polymerization initiator or the like.

Examples of the radical polymerization initiator include azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-cyclopropyl). Azo radical initiators such as propionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate;
Examples thereof include peroxide radical initiators such as benzoyl peroxide, t-butyl hydroperoxide and cumene hydroperoxide.
Of these, AIBN and dimethyl 2,2′-azobisisobutyrate are preferable, and AIBN is more preferable. These radical 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, methyl ethyl ketone, 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 solvents used in these polymerizations may be used alone or in combination of two or more.

The lower limit of the reaction temperature in the above polymerization is preferably 40°C, more preferably 50°C. The upper limit of the reaction temperature is preferably 150°C, more preferably 120°C. The lower limit of the reaction time in the polymerization is preferably 1 hour, more preferably 2 hours. The upper limit of the reaction time is preferably 48 hours, more preferably 24 hours.

The lower limit of the polystyrene reduced weight average molecular weight (Mw) of the polymer [A] by gel permeation chromatography (GPC) is preferably 1,000, more preferably 2,000, still more preferably 3,000, and 4, 000 is particularly preferred. The upper limit of Mw is preferably 50,000, more preferably 30,000, further preferably 20,000, particularly preferably 10,000. By setting the Mw of the polymer [A] within the above range, the coating property of the radiation-sensitive resin composition can be improved. If the Mw of the polymer [A] is less than the above lower limit, a resist pattern having sufficient heat resistance may not be obtained. If the Mw of the polymer [A] exceeds the above upper limit, the developability of the resist film may decrease.

The upper limit of the ratio (Mw/Mn) of Mw to polystyrene-reduced number average molecular weight (Mn) of the polymer [A] by GPC is usually 5, preferably 3, 3 is more preferable, and 1.5 is particularly preferable. preferable. The lower limit of the ratio is usually 1.

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: 2 "G2000HXL", 1 "G3000HXL", 1 "G4000HXL" from Tosoh Corp. Column temperature: 40°C
Elution solvent: Tetrahydrofuran Flow rate: 1.0 mL/min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Detector: Differential refractometer Standard substance: Monodisperse polystyrene

<[B] acid generator>
The acid generator [B] is a substance that generates an acid upon exposure. The generated acid dissociates the acid dissociable group of the [A] polymer or the like to generate a carboxy group or the like, and the solubility of these polymers in a developing solution is changed. Therefore, the radiation-sensitive resin composition From this, a resist pattern can be formed. The form of the [B] acid generator contained in the radiation-sensitive resin composition may be a low-molecular compound as described below (hereinafter, appropriately referred to as “[B] acid generator”), and it may be included in the polymer. The form incorporated as a part or both forms may be used.

Examples of the acid generator [B] include onium salt compounds, N-sulfonyloxyimide compounds, halogen-containing compounds and diazoketone compounds.

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

Specific examples of the acid generator [B] include the compounds described in paragraphs [0080] to [0113] of JP 2009-134088 A.

As the acid generator [B], a compound represented by the following formula (4) is preferable. When the acid generator [B] is a compound represented by the following formula (4), the diffusion length of the acid generated by exposure in the resist film due to interaction with the polar structure of the polymer [A] and the like. Is more appropriately shortened, and as a result, the LWR performance and MEEF performance of the radiation-sensitive resin composition can be further improved.

In the above formula (4), R ^a1 is a monovalent group containing an alicyclic structure having 6 or more ring members or a monovalent group containing an aliphatic heterocyclic structure having 6 or more ring members. R ^a2 is a fluorinated alkanediyl group having 1 to 10 carbon atoms. M ⁺ is a monovalent radiation-sensitive onium cation.

The monovalent group containing an alicyclic structure having 6 or more ring members represented by R ^a1 is, for example, a monocyclic cycloalkyl group such as a cyclooctyl group, a cyclononyl group, a cyclodecyl group or a cyclododecyl group;
Polycyclic cycloalkyl groups such as norbornyl group, adamantyl group, hydroxyadamantyl group, tricyclodecyl group, tetracyclododecyl group;
A monocyclic cycloalkenyl group such as a cyclooctenyl group or a cyclodecenyl group;
Examples thereof include polycyclic cycloalkenyl groups such as norbornenyl group and tricyclodecenyl group.

Examples of the monovalent group containing an aliphatic heterocyclic structure having 6 or more ring members represented by R ^a1 include, for example, norbornane lactone-yl group and 5-oxo-4-oxatricyclo[4.3.1.1]. ^3,8 ] group containing a lactone structure such as undecane-yl group;
A group containing a sultone structure such as a norbornane sultone-yl group;
Oxygen atom-containing heterocyclic group such as oxacycloheptyl group and oxanorbornyl group;
Nitrogen atom-containing heterocyclic group such as azacyclohexyl group, azacycloheptyl group and diazabicyclooctane-yl group;
Examples thereof include a sulfur atom-containing heterocyclic group such as a thiacycloheptyl group and a thianorbornyl group.

The lower limit of the number of ring members of the group represented by R ^a1 is preferably 8, more preferably 9, and even more preferably 10. The upper limit of the number of ring members is preferably 15, more preferably 14 and even more preferably 13. By setting the number of ring members in the above range, the diffusion length of the acid can be further appropriately shortened.

Among them, the R ^a1 is preferably a monovalent group containing an alicyclic structure having 9 or more ring members, a monovalent group containing an aliphatic heterocyclic structure having 9 or more ring members, and an adamantyl group or hydroxyadamantyl group. Group, norbornane lactone-yl group and 5-oxo-4-oxatricyclo[4.3.1.1 ^3,8 ]undecane-yl group are more preferred, and adamantyl group is still more preferred.

As the fluorinated alkanediyl group having 1 to 10 carbon atoms represented by R ^a2 , for example, one or more hydrogen atoms contained in the alkanediyl group having 1 to 10 carbon atoms such as methanediyl group, ethanediyl group and propanediyl group. And a group in which is substituted with a fluorine atom.
Among these, SO ₃ ^- fluorinated alkane diyl group which has a fluorine atom to carbon atom is bonded to adjacent groups are preferred, SO ₃ ^- 2 fluorine atoms to the carbon atom adjacent to the group is attached Fluorinated alkanediyl groups are more preferred, 1,1-difluoromethanediyl group, 1,1-difluoroethanediyl group, 1,1,3,3,3-pentafluoro-1,2-propanediyl group, 1,1 ,2,2-Tetrafluoroethanediyl group, 1,1,2,2-tetrafluorobutanediyl group and 1,1,2,2-tetrafluorohexanediyl group are more preferable.

The monovalent radiation-sensitive onium cation represented by M ⁺ is a cation that decomposes upon irradiation with radiation. In the exposed area, a sulfonic acid is generated from the proton generated by the decomposition of the radiation-sensitive onium cation and the sulfonate anion. Examples of the monovalent radiation-sensitive onium cation represented by M ⁺ include a radiation-sensitive onium cation containing a sulfur atom and an iodine atom. Examples of the cation containing a sulfur atom include a sulfonium cation and tetrahydrothiophenium cation, and examples of the cation containing an iodine atom include an iodonium cation. Among these, a cation represented by the following formula (X-1), a cation represented by the following formula (X-2) and a cation represented by the following formula (X-3) are preferable.

In the above formula (X-1), R ^a1 , R ^a2 and R ^a3 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alkyl group. aromatic hydrocarbon group having 6 to 12 carbon atoms, a or a -OSO ₂ -R ^P or _-SO 2 -R ^Q, or two or more are combined with each other configured ring of these groups .. R ^P and R ^Q are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms. Alternatively, it is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k1, k2, and k3 are each independently an integer of 0 to 5. When R ^{a1 to} R ^a3 and R ^P and R ^Q are each plural, the plural R ^{a1 to} R ^a3 and R ^P and R ^Q may be the same or different.
In the above formula (X-2), R ^b1 is a substituted or unsubstituted linear or branched alkyl group having 1 to 8 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms. It is a base. k4 is an integer of 0-7. If R ^b1 is plural, the plurality of R ^b1 may be the same or different, and plural R ^b1 may represent a constructed ring aligned with each other.
R ^b2 is a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. k5 is an integer of 0-6. If R ^b2 is plural, the plurality of R ^b2 may be the same or different, and plural R ^b2 may represent a keyed configured ring structure. t is an integer of 0 to 3.
In the above formula (X-3), R ^c1 and R ^c2 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted C 6 12 aromatic hydrocarbon group, or an -OSO ₂ -R ^R or _-SO 2 -R ^S, or two or more are combined with each other configured ring of these groups. R ^R and R ^S are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms. Alternatively, it is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k6 and k7 are each independently an integer of 0 to 5. R ^{c1, R} c2, ^R when ^R and ^{R S} is plural respective plurality of ^{R c1,} R c2, ^{R R} and ^{R S} may have respectively the same or different.

Examples of the unsubstituted linear alkyl group represented by R ^{a1 to} R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group. Etc.
Examples of the unsubstituted branched alkyl group represented by R ^{a1 to} R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 include, for example, i-propyl group, i-butyl group, sec-butyl group, t A butyl group and the like.
Examples of the unsubstituted aromatic hydrocarbon group represented by R ^{a1 to} R ^a3 , R ^c1 and R ^c2 include an aryl group such as a phenyl group, a tolyl group, a xylyl group, a mesityl group and a naphthyl group; a benzyl group; Examples thereof include an aralkyl group such as a phenethyl group.
Examples of the unsubstituted aromatic hydrocarbon group represented by R ^b1 and R ^b2 include a phenyl group, a tolyl group and a benzyl group.

Examples of the substituent which may substitute the hydrogen atom of the alkyl group and the aromatic hydrocarbon group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, a hydroxy group, a carboxy group and a cyano group. , A nitro group, an alkoxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, an acyl group, an acyloxy group and the like.
Among these, a halogen atom is preferable, and a fluorine atom is more preferable.

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

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

As M ⁺ , a cation represented by the above formula (X-1) is preferable, and a triphenylsulfonium cation is more preferable.

Examples of the acid generator represented by the above formula (4) include compounds represented by the following formulas (4-1) to (4-15) (hereinafter, “compounds (4-1) to (4-15). )”).

In the above formulas (4-1) to (4-15), M ⁺ has the same meaning as in the above formula (4).

Among these, as the acid generator [B], an onium salt compound is preferable, a sulfonium salt is more preferable, and a compound (4-1), a compound (4-2), a compound (4-12) and a compound (4- 13) is more preferable.

When the [B] acid generator is a [B] acid generator, the lower limit of the content of the [B] acid generator is preferably 0.1 parts by mass relative to 100 parts by mass of the [A] polymer, 0.5 parts by mass is more preferable, 1 part by mass is further preferable, and 3 parts by mass is particularly preferable. The upper limit of the content is preferably 30 parts by mass, more preferably 20 parts by mass, further preferably 15 parts by mass, and particularly preferably 10 parts by mass. By setting the content of the acid generator [B] in the above range, the sensitivity of the radiation-sensitive resin composition can be further improved. The radiation-sensitive resin composition may contain one or two or more [B] acid generators.

<[C] Acid diffusion controller>
The radiation-sensitive resin composition may contain a [C] acid diffusion controller, if necessary. The [C] acid diffusion controller has an effect of controlling the diffusion phenomenon of the acid generated from the [B] acid generator in the resist film by exposure and suppressing an unfavorable chemical reaction in the non-exposed region. This further improves the resolution of the radiation-sensitive resin composition. Further, the storage stability of the radiation-sensitive resin composition is further improved, and it is possible to suppress the change in the line width of the resist pattern due to the variation of the leaving time from the exposure to the development processing, and the radiation sensitivity excellent in the process stability. A resin composition is obtained. As a form of containing the [C] acid diffusion controller in the radiation-sensitive resin composition, even a free compound (hereinafter, appropriately referred to as "[C] acid diffusion controller") is incorporated as a part of the polymer. Both of these forms may be used.

Examples of the [C] acid diffusion controller include compounds represented by the following formula (5) (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 (5), R ²⁵ , R ²⁶ and R ²⁷ 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 and tri-n-pentylamine; fragrances such as aniline. Group amines and the like can be mentioned. Among these, trialkylamines are preferable, and tri-n-pentylamine is more preferable.

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-(undecan-1-ylcarbonyloxyethyl)morpholine; pyrazine and pyrazole. .. Among these, N-(undecan-1-ylcarbonyloxyethyl)morpholine is preferable.

A compound having an acid-dissociable group can also be used as the nitrogen-containing organic compound. 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. Among these, Nt-amyloxycarbonyl-4-hydroxypiperidine is preferable.

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 onium salt compounds that decompose by exposure and lose the acid diffusion controllability. Examples of the onium salt compound include a sulfonium salt compound represented by the following formula (6-1) and an iodonium salt compound represented by the following formula (6-2).

In formulas (6-1) and (6-2), R ^{28 to} R ³² 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 (6-3). R ^β is an alkyl group, an aryl group or an aralkyl group.

In the above formula (6-3), R ³³ is a linear or branched alkyl group having 1 to 12 carbon atoms in which a part or all of hydrogen atoms may be substituted with a fluorine atom, or a carbon number of 1. To 12 straight-chain or branched alkoxy groups. u is an integer of 0-2.

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

Among these, the photo-degradable base is preferably a sulfonium salt, more preferably a triarylsulfonium salt, further preferably a triphenylsulfonium salt, and a triphenylsulfonium 2,4,6-triisopropylbenzene-1-sulfonate. And triphenylsulfonium 10-camphor sulfonate are particularly preferred.

When the [C] acid diffusion control agent is a [C] acid diffusion control agent, the lower limit of the content of the [C] acid diffusion control agent is 0.1 part by mass with respect to 100 parts by mass of the [A] polymer. Parts is preferred, 0.5 parts by mass is more preferred, and 1 part by mass is even more preferred. As a maximum of the above-mentioned content, 20 mass parts is preferred, 15 mass parts is more preferred, and 10 mass parts is still more preferred. By setting the content of the acid diffusion controller [C] in the above range, the above-mentioned lithographic performance of the radiation-sensitive resin composition can be further improved. The radiation-sensitive resin composition may contain one or more [C] acid diffusion regulators.

<[D] polymer>
The polymer [D] has a higher fluorine atom content (mass %) than the polymer [A]. Since the radiation-sensitive composition contains the [D] polymer, when the resist film is formed, its distribution is near the surface of the resist film due to the oil-repellent characteristics of the [D] polymer in the film. It tends to be unevenly distributed, and it is possible to suppress 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 this [D] polymer, 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. Further, the receding contact angle between the resist film and the liquid immersion medium is increased, 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. As a maximum of the above-mentioned fluorine atom content rate, 60 mass% is preferred, 50 mass% is more preferred, 40 mass% is still more preferred, and 30 mass% is especially preferred. By setting the fluorine atom content of the polymer [D] within the above range, a suitable resist film can be formed by the liquid immersion exposure method. The fluorine atom content (mass %) of the polymer can be calculated from the structure of the polymer obtained by ¹³ C-NMR spectrum measurement.

The form of the fluorine atom contained in the polymer [D] is not particularly limited and may be bonded to any of the main chain, the side chain and the terminal, but a structural unit containing a fluorine atom (hereinafter, referred to as “structural unit (VII)”). (Also referred to as)) is preferable. In addition to the structural unit (VII), the polymer [D] preferably has a structural unit containing an acid dissociable group from the viewpoint of improving the development defect suppressing property of the radiation-sensitive resin composition. Examples of the structural unit containing an acid dissociable group include the structural unit (II) in the polymer [A].

The polymer [D] preferably has an alkali-dissociable group. When the polymer [D] has an alkali dissociative group, the resist film surface can be effectively changed from hydrophobic to hydrophilic during alkali development, and the development defect suppression of the radiation-sensitive resin composition is improved. .. The “alkali-dissociable group” is a group that substitutes a hydrogen atom of a carboxy group, a hydroxy group, or the like, and dissociates in an alkaline aqueous solution (eg, a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23° C.). Refers to the group

Examples of the structural unit (VII) include a structural unit represented by the following formula (7a) (hereinafter, also referred to as “structural unit (VIIa)”) and a structural unit represented by the following formula (7b) (hereinafter, “structure”). Unit (VIIb)”) is preferred. The polymer [D] may have one type or two or more types of the structural unit (VIIa) and the structural unit (VIIb), respectively.

[Structural unit (VIIa)]
The structural unit (VIIa) is a structural unit represented by the following formula (7a). The polymer [D] has the structural unit (VIIa), whereby the fluorine atom content can be adjusted.

In the above formula (7a), R ^d is a hydrogen 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 fluorine-cycloaliphatic hydrocarbon group having a monovalent fluorinated chain hydrocarbon group or a 4 to 20 carbon atoms having 1 to 6 carbon atoms.

From the viewpoint of the copolymerizability of the monomer giving the structural unit (VIIa) and the like, R ^d is preferably a hydrogen atom and a methyl group, more preferably a methyl group.

As the _{G, -CO-O -, -} SO 2 -O-NH -, - CO-NH- and -O-CO-NH- are preferred, -CO-O-are more preferred.

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, 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, perfluoro i-butyl group, perfluoro t-butyl group, 2,2,3,3,4,4,5,5-octafluoropentyl group, perfluorohexyl group and the like.

Examples of the monovalent fluorinated alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ^e include, for example, monofluorocyclopentyl group, difluorocyclopentyl group, perfluorocyclopentyl group, monofluorocyclohexyl group, difluorocyclopentyl group. , Perfluorocyclohexylmethyl group, fluoronorbornyl group, fluoroadamantyl group, fluorobornyl group, fluoroisobornyl group, fluorotricyclodecyl group, fluorotetracyclodecyl group and the like.

Of these, R ^e is preferably a fluorinated chain hydrocarbon group, and is 2,2,2-trifluoroethyl group or 1,1,1,3,3,3-hexafluoro-2-propyl Groups are more preferred.

When the polymer [D] has the structural unit (VIIa), the lower limit of the content of the structural unit (VIIa) is preferably 3 mol% with respect to all the structural units constituting the polymer [D]. Mol% is more preferable, and 10 mol% is further preferable. The upper limit of the content is preferably 90 mol%, more preferably 70 mol%, and even more preferably 50 mol%. By setting the content ratio of the structural unit (VIIa) in the above range, the fluorine atom content rate of the polymer [D] can be adjusted more appropriately.

[Structural unit (VIIb)]
The structural unit (VIIb) is a structural unit represented by the following formula (7b). Since the polymer [D] has the structural unit (VIIb), the fluorine atom content can be adjusted and the water repellency and hydrophilicity before and after the alkali development can be changed more appropriately.

In the above formula (7b), R ^f is a hydrogen atom, a methyl group or a trifluoromethyl group. R ³⁰ is a (v+1)-valent hydrocarbon group having 1 to 20 carbon atoms, or an oxygen atom, a sulfur atom, —NR′—, a carbonyl group, —CO—O— at the R ³¹ side end of this hydrocarbon group. Alternatively, it has a structure in which —CO—NH— is bound. R'is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ³¹ is a single bond or a divalent organic group having 1 to 20 carbon atoms. W ¹ is a single bond or 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- * is .R" is a monovalent hydrocarbon group having a hydrogen atom or 1 to 10 carbon atoms .. * Indicates a site that binds to R ³² . R ³² is a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms. v is an integer of 1 to 3. However, when v is 1, R ³⁰ may be a single bond. When v is 2 or 3, a plurality of R ³¹ , W ¹ , A ¹ and R ³² may be the same or different. When W ¹ is a single bond, R ³² is a group containing a fluorine atom.

As R ^f , 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 (VIIb).

Examples of the (v+1)-valent hydrocarbon group having 1 to 20 carbon atoms represented by R ³⁰ include v hydrogen atoms from the monovalent hydrocarbon group exemplified as R ² in the above formula (1). The removed groups and the like can be mentioned.
As v, 1 and 2 are preferable, and 1 is more preferable.
As R ³⁰ , when v is 1, a single bond and a divalent hydrocarbon group are preferable, a single bond and an alkanediyl group are more preferable, a single bond and an alkanediyl group having 1 to 4 carbon atoms are further preferable, Single bonds, methanediyl groups and propanediyl groups are particularly preferred.

Examples of the divalent organic group having 1 to 20 carbon atoms represented by R ³¹ include monovalent organic groups having 1 to 20 carbon atoms exemplified as L in the above formulas (1-1) to (2-4). The group etc. which removed one hydrogen atom from a group are mentioned.
As R ³¹ , the group having a single bond and a lactone structure is preferable, the group having a single bond and a polycyclic lactone structure is more preferable, and the group having a single bond and a norbornane lactone structure is more preferable.

Examples of the divalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms represented by W ¹ include fluoromethanediyl group, difluoromethanediyl group, fluoroethanediyl group, difluoroethanediyl group, tetrafluoroethanediyl group. Groups, fluorinated alkanediyl groups such as hexafluoropropanediyl group and octafluorobutanediyl group;
Examples thereof include fluorinated alkenediyl groups such as fluoroethenediyl group and difluoroethenediyl group.
Among these, a fluorinated alkanediyl group is preferable, and a difluoromethanediyl group is more preferable.

As the ^{A 1,} an oxygen _{atom, -CO-O - *, -} SO 2 -O- * are preferred, -CO-O- * is more preferable.

Examples of the monovalent organic group having 1 to 30 carbon atoms represented by R ³² include an alkali dissociable group, an acid dissociable group, and a hydrocarbon group having 1 to 30 carbon atoms. Among these, R ³² is preferably an alkali-dissociable group. When R ³² is an alkali dissociative group, the surface of the resist film can be effectively changed from hydrophobic to hydrophilic at the time of alkali development, and the development defect suppressing property of the radiation-sensitive resin composition is further improved. improves.

When R ³² is an alkali dissociable group, R ³² is preferably a group represented by the following formulas (iii) to (v) (hereinafter, also referred to as “groups (iii) to (v)”). ..

In the above formula (iii), R ^3a and R ^3b are each independently a monovalent organic group having 1 to 20 carbon atoms, or these groups are combined with each other and are formed together with a carbon atom to which they are bonded. Represents an alicyclic structure having 3 to 20 ring members.

In the above formula (iv), R ^3c and R ^3d are each independently a monovalent organic group having 1 to 20 carbon atoms, or these groups are combined with each other and constituted with a nitrogen atom to which they are bonded. Represents a heterocyclic structure having 3 to 20 ring members.

In the above formula (v), R ^3e is a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms.

As the monovalent organic group having 1 to 20 carbon atoms represented by R ^3a , R ^3b , R ^3c and R ^3d and the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^3e , Examples thereof include the same groups as the monovalent hydrocarbon groups exemplified as R ^{2 in the} above formula (1).

Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ^3e include, for example, a part of hydrogen atoms contained in the groups exemplified as the monovalent hydrocarbon group having 1 to 20 carbon atoms or Examples thereof include groups in which all are substituted with fluorine atoms.

The group (iii) is a group represented by the following formulas (iii-1) to (iii-4), and the group (iv) is a group represented by the following formula (iv-1). As (v), groups represented by the following formulas (v-1) to (v-5) are preferable.

Among these, the group represented by the above formula (v-3) and the group represented by the above formula (v-5) are preferable.

Further, when R ³² is a hydrogen atom, the solubility of the [D] polymer in an alkali developing solution is improved, which is preferable. In this case, when A ¹ is an oxygen atom and W ¹ is a 1,1,1,3,3,3-hexafluoro-2,2-methanediyl group, the solubility is further improved.

When the polymer [D] has the structural unit (VIIb), the lower limit of the content of the structural unit (VIIb) is preferably 10 mol% based on all the structural units constituting the polymer [D], 20 mol% is more preferable, and 40 mol% is further preferable. The upper limit of the content ratio is preferably 90 mol%, more preferably 85 mol%, even more preferably 80 mol%. By setting the content ratio of the structural unit (VIIb) in the above range, the water repellency and hydrophilicity of the resist film surface formed from the radiation-sensitive resin composition before and after alkali development can be adjusted more appropriately.

As a minimum of the content rate of the above-mentioned structural unit (VII), 10 mol% is preferred to all the structural units which constitute a [D] polymer, 20 mol% is more preferred, and 25 mol% is still more preferred. The upper limit of the content ratio is preferably 90 mol%, more preferably 80 mol%, and even more preferably 75 mol%.

The lower limit of the content of the structural unit containing an acid dissociable group in the [D] polymer is preferably 10 mol%, more preferably 20 mol%, based on all structural units constituting the [D] polymer. 25 mol% is more preferable. The upper limit of the content ratio is preferably 90 mol%, more preferably 80 mol%, and even more preferably 75 mol%. By setting the content ratio of the structural unit containing an acid dissociable group in the polymer [D] within the above range, the development defect suppressing property of the radiation-sensitive resin composition can be further improved.

The lower limit of the content of the [D] polymer is preferably 0.1 parts by mass, more preferably 0.2 parts by mass, and further preferably 0.5 parts by mass with respect to 100 parts by mass of the [A] polymer. 1 part by mass is particularly preferred. The upper limit of the content is preferably 30 parts by mass, more preferably 20 parts by mass, further preferably 15 parts by mass, and particularly preferably 10 parts by mass.

The [D] polymer can be synthesized in the same manner as the above-mentioned [A] polymer.

The lower limit of the polystyrene reduced weight average molecular weight (Mw) of the polymer [D] by gel permeation chromatography (GPC) is preferably 1,000, more preferably 2,000, further preferably 3,000, and 4, 000 is particularly preferred. The upper limit of Mw is preferably 50,000, more preferably 30,000, further preferably 20,000, particularly preferably 10,000. By setting the Mw of the polymer [D] in the above range, the development defect suppressing property of the radiation-sensitive resin composition can be improved.

The upper limit of the ratio (Mw/Mn) of Mw to the polystyrene reduced number average molecular weight (Mn) of the polymer [D] by GPC is usually 5, preferably 3 and more preferably 2.5. The lower limit of the ratio is usually 1.

<[E] solvent>
The radiation-sensitive resin composition contains a solvent [E]. The solvent [E] can dissolve or disperse at least the polymer [A], the acid generator [B], the acid diffusion controller [C], the polymer [D], and other optional components described below. There is no particular limitation as long as it exists. Examples of the [E] solvent include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents and hydrocarbon solvents.

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 3 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 monoethyl ether.

Examples of ether solvents include dialiphatic ether solvents such as diethyl ether, dipropyl ether and dibutyl ether;
Aromatic ring-containing ether solvents such as anisole and diphenyl ether;
Examples include cyclic ether solvents such as tetrahydrofuran and dioxane.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, methyl-n-amyl ketone, ethyl-n-butyl ketone and methyl-n-hexyl. Chain ketone solvents such as ketones, di-iso-butyl ketone, trimethylnonanone, acetophenone;
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone;
Examples thereof include diketone solvents such as 2,4-pentanedione and acetonylacetone.

Examples of the amide solvent include chain amides such as N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide and N-methylpropionamide. System solvent;
Examples thereof include cyclic amide solvents such as N-methylpyrrolidone and N,N′-dimethylimidazolidinone.

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

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 solvent [E] may be used alone or in combination of two or more.

<Other optional ingredients>
The radiation-sensitive resin composition may contain other optional components in addition to the components [A] to [E]. Examples of the other optional components include an uneven distribution promoter, 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.

[Distribution promoter]
When the radiation-sensitive resin composition contains a water-repellent polymer additive such as a [D] polymer, the uneven distribution promoter can be used to more efficiently add the water-repellent polymer additive to the resist film surface. It has the effect of segregating to. By adding the uneven distribution promoter to the radiation-sensitive resin composition, the amount of the water-repellent polymer additive added can be made smaller than before. Therefore, the elution of components from the resist film to the immersion liquid can be further suppressed without impairing the LWR performance and MEEF performance, and the immersion exposure can be performed at a higher speed by the high-speed scanning, resulting in the watermark. It is possible to improve the hydrophobicity of the resist film surface, which suppresses defects such as defects derived from liquid immersion. Examples of such an uneven distribution promoting agent include low molecular weight compounds having a relative dielectric constant of 30 to 200 and a boiling point of 100° C. or higher 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.
Examples of the polyhydric alcohol include glycerin and the like.

The lower limit of the content of the uneven distribution promoter is preferably 10 parts by mass, more preferably 15 parts by mass, and even more preferably 20 parts by mass with respect to 100 parts by mass of the total amount of the polymer in the radiation-sensitive resin composition. , 25 parts by mass are particularly preferable. The upper limit of the content is preferably 500 parts by mass, more preferably 300 parts by mass, further preferably 200 parts by mass, and particularly preferably 150 parts by mass.

(Surfactant)
The surfactant has an effect of improving coating property, 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. Nonionic surfactants such as stearate; as commercially available products, KP341 (Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, the same No. 95 (above, Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (above, Tochem Products Co.), Megafac F171, F173 (above DIC), 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 Co., Ltd.) and the like. Can be mentioned. The upper limit of the content of the surfactant in the radiation-sensitive resin composition is usually 2 parts by mass with respect to 100 parts by mass of the polymer [A].

(Alicyclic skeleton-containing compound)
The alicyclic skeleton-containing compound 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 usually 5 parts by mass with respect to 100 parts by mass of the [A] polymer.

(Sensitizer)
The sensitizer has the effect of increasing the amount of acid produced from the [B] acid generator and the like, and has the effect of improving the "apparent sensitivity" of the radiation-sensitive resin composition.

Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines and the like. These sensitizers may be used alone or in combination of two or more kinds. The upper limit of the content of the sensitizer in the radiation-sensitive resin composition is usually 2 parts by mass with respect to 100 parts by mass of the polymer [A].

<Method for preparing radiation-sensitive resin composition>
The radiation-sensitive resin composition is, for example, [A] polymer, [B] acid generator, [C] acid diffusion controller, [D] polymer, [E] solvent, and others which are optionally contained. It can be prepared by mixing any of the above components in a predetermined ratio, and preferably filtering with a membrane filter having a pore size of about 0.2 μm. As a minimum of solid content density of the radiation sensitive resin constituent concerned, 0.1 mass% is preferred, 0.5 mass% is more preferred, 1 mass% is still more preferred, and 1.5 mass% is especially preferred. The upper limit of the solid content concentration is preferably 50% by mass, more preferably 30% by mass, further preferably 20% by mass, and particularly preferably 10% by mass.

<Method of forming resist pattern>
The resist pattern forming method includes a step of forming a resist film (hereinafter also referred to as “resist film forming step”), a step of exposing the resist film (hereinafter also referred to as “exposure step”), and the exposed resist film. And a step of developing (hereinafter, also referred to as “developing step”). The resist film is formed of the radiation-sensitive resin composition described above.

According to the resist pattern forming method, since the radiation-sensitive resin composition described above is used, it is possible to form a resist pattern having a small LWR while exhibiting excellent MEEF performance. Hereinafter, each step of the resist pattern forming method will be described.

[Resist film formation process]
In this step, a resist film is formed from the radiation sensitive resin composition. Examples of the substrate on which the resist film is formed include conventionally known substrates such as a silicon wafer, silicon dioxide, and a wafer covered with aluminum. Further, for example, an organic or inorganic antireflection film disclosed in Japanese Patent Publication No. 6-12452 or Japanese Patent Laid-Open No. 59-93448 may be formed on the substrate. Examples of the coating method include spin coating (spin coating), cast coating, and roll coating. After application, prebaking (PB) may be performed to volatilize the solvent in the coating film, if necessary. As a minimum of PB temperature, 60 °C is preferred and 80 °C is more preferred. The upper limit of the PB temperature is preferably 140°C, more preferably 120°C. The lower limit of the PB time is preferably 5 seconds, more preferably 10 seconds. The upper limit of the PB time is preferably 600 seconds, more preferably 300 seconds. The lower limit of the thickness of the resist film formed is preferably 10 nm, more preferably 20 nm, and even more preferably 50 nm. The upper limit of the film thickness is preferably 1,000 nm, more preferably 500 nm, even more preferably 200 nm.

[Exposure process]
In this step, the resist film formed in the resist film forming step is irradiated with radiation through a photomask or the like (in some cases, through an immersion medium such as water) and exposed. Examples of radiation include electromagnetic waves such as visible rays, ultraviolet rays, far ultraviolet rays, extreme ultraviolet rays (EUV), X-rays and γ rays, and charged particle rays such as electron rays and α rays, depending on the line width of a target pattern. Are listed. 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 liquid immersion exposure, examples of the liquid immersion liquid used include water and a fluorine-based inert liquid. The immersion liquid is preferably a liquid which is transparent to the exposure wavelength and has a temperature coefficient of refractive index as small as possible so as to minimize 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 to dissociate the acid-dissociable group of the [A] polymer or the like in the exposed portion of the resist film by the acid generated from the [B] acid generator by the exposure. Is preferably promoted. This PEB causes a difference in the solubility in the developing solution between the exposed portion and the unexposed portion. As a minimum of PEB temperature, 50 °C is preferred, 70 °C is more preferred, and 90 °C is even more preferred. The upper limit of the PEB temperature is preferably 180°C, more preferably 130°C, and even more preferably 110°C. As a minimum of PEB time, 5 seconds are preferred and 10 seconds are more preferred. The upper limit of the PEB time is preferably 600 seconds, more preferably 300 seconds.

[Development process]
In this step, the resist film exposed in the above exposure step is developed. Thereby, a predetermined resist pattern can be formed. After development, it is common to wash with a rinse liquid such as water or alcohol and dry. As the developing method in the developing step, alkali developing or organic solvent developing may be used.

In the case of alkali development, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n can be used as the developer used for the above-mentioned development. -Propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, Examples thereof include an aqueous alkaline solution in which at least one alkaline compound such as 1,5-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, alcohol solvents, and other organic solvents, or solvents containing organic solvents. Examples of the organic solvent include one or more of the solvents exemplified as the solvent [E] of the radiation-sensitive resin composition. 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, and particularly preferably 99% by mass. Examples of the components other than the organic solvent in the developer 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 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 time (paddle method) ), a method of spraying the developing solution on the surface of the substrate (spray method), a method of continuously applying the developing solution onto the substrate rotating at a constant speed while scanning the developing solution application nozzle at a constant speed (dynamic dispensing method) Etc.

<Polymer>
The polymer of the present invention is a polymer having the above structural unit (I′).
The polymer can further improve the LWR performance and the MEEF performance of the radiation-sensitive resin composition containing the polymer. Therefore, the polymer can be preferably used as a component of the radiation-sensitive resin composition.

<Method for producing compound>
The method for producing the compound of the present invention is a method for producing the compound (1′-a), which comprises a step of subjecting the compound (a) and the compound (b) to a dehydrohalogenation condensation reaction in the presence of a base. ..

According to the method for producing the compound, the compound (I) can be easily produced with high yield.

The method for producing the polymer and the compound is described above in the section of the polymer [A] of the radiation sensitive resin composition.

Hereinafter, the present invention will be specifically described based on Examples, but the present invention is not limited to these Examples. The methods for measuring various physical properties are shown below.

[Mw and Mn]
For the Mw and Mn of the polymer, a GPC column (two "G2000HXL", one "G3000HXL" and one "G4000HXL") manufactured by Tosoh Corporation was used, and a flow rate: 1.0 ml/min, an elution solvent: tetrahydrofuran, a column It was measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under the analysis conditions of temperature: 40°C.

[ ¹³ C-NMR analysis]
The ¹³ C-NMR analysis for determining the content ratio of the structural unit of the polymer was measured using a nuclear magnetic resonance apparatus (“JNM-Delta 400” manufactured by JEOL Ltd.).

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

[Synthesis of [A] Polymer]
[Example 1]
16.15 g (50 mol%) of the compound (M-1) and 13.85 g (50 mol%) of the compound (M-6) were dissolved in 60 g of 2-butanone, and 1.35 g of AIBN as a radical polymerization initiator. (5 mol% based on the total amount of the compounds) was dissolved to prepare a monomer solution. Next, a 100 mL three-necked flask containing 30 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80° C. with stirring, and the monomer solution prepared above was added dropwise with a dropping funnel over 3 hours. .. The polymerization reaction was carried out for 6 hours, with the start of dropping being the start time of the polymerization reaction. After the completion of the polymerization reaction, the polymerization reaction liquid was cooled with water and cooled to 30°C or lower. The cooled polymerization reaction solution was poured into 600 g of methanol, and the white powder deposited was filtered off. The filtered white powder was washed twice with 120 g of methanol, then filtered and dried at 50° C. for 17 hours to synthesize a white powdery polymer (A-1) (yield 71%). The polymer (A-1) had an Mw of 6,800 and an Mw/Mn of 1.3. As a result of ¹³ C-NMR analysis, the content ratios of the structural units derived from (M-1) and (M-6) were 48.1 mol% and 51.9 mol %, respectively.

[Examples 2 to 6 and Synthesis Examples 1 to 3]
Each polymer was synthesized in the same manner as in Example 1 except that the types and amounts of the compounds shown in Table 1 were used. The yield (%) of each polymer synthesized, Mw and Mw/Mn, and the content ratio (mol%) of each structural unit are also shown in Table 1.

[Synthesis of [D] Polymer]
[Synthesis example 4]
The compound (M-10) 79.9 g (70 mol %) and the compound (M-11) 20.91 g (30 mol %) were dissolved in 100 g of 2-butanone, and dimethyl 2, as a radical polymerization initiator. A monomer solution was prepared by dissolving 4.77 g of 2'-azobisisobutyrate. Next, a 1,000 mL three-necked flask containing 100 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80° C. with stirring, and the above-prepared monomer solution was added to the dropping funnel over 3 hours. Dropped. The polymerization reaction was carried out for 6 hours, with the start of dropping being the start time of the polymerization reaction. After the completion of the polymerization reaction, the polymerization reaction liquid was cooled with water and cooled to 30°C or lower. After transferring this polymerization reaction solution to a 2 L separating funnel, the polymerization reaction solution was uniformly diluted with 150 g of n-hexane, and 600 g of methanol was added and mixed. Next, 30 g of distilled water was added, and the mixture was further stirred and left standing for 30 minutes. Then, the lower layer was recovered and used as a propylene glycol monomethyl ether acetate solution of the polymer (D-1) (yield 60%). The polymer (E-1) had Mw of 7,200 and Mw/Mn of 2.00. As a result of ¹³ C-NMR analysis, the content rates of the structural units derived from (M-10) and (M-11) were 71.1 mol% and 28.9 mol%, respectively.

<Preparation of radiation-sensitive resin composition>
The respective components used in the preparation of the radiation sensitive resin composition are shown below.

[[B] acid generator]
Each structural formula is shown below.
B-1: triphenylsulfonium 2-(adamantan-1-ylcarbonyloxy)-1,1,3,3,3-pentafluoropropane-1-sulfonate B-2: triphenylsulfonium norbornanesultone-2-yloxy Carbonyldifluoromethanesulfonate B-3: Triphenylsulfonium 3-(piperidin-1-ylsulfonyl)-1,1,2,2,3,3-hexafluoropropane-1-sulfonate B-4: Triphenylsulfonium adamantane- 1-yloxycarbonyldifluoromethanesulfonate

[[C] Acid diffusion control agent]
Each structural formula is shown below.
C-1: triphenylsulfonium 2,4,6-triisopropylbenzene-1-sulfonate C-2: triphenylsulfonium 10-camphorsulfonate C-3: N-(n-undecan-1-ylcarbonyloxyethyl)morpholine C-4: tri-n-pentylamine

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

[[F] uneven distribution promoting agent]
F-1: γ-butyrolactone

[Example 7]
(A-1) 100 parts by mass as a polymer, (B-1) 8.5 parts by mass as a [B] acid generator, (C-1) 2 as a [C] acid diffusion controller. .3 parts by mass, (D-1) 3 parts by mass as a [D] polymer, (E-1) 2,427 parts by mass and (E-2) 1,040 parts by mass as an [E] solvent, and [ F] 100 parts by mass of (F-1) as an uneven distribution promoter is mixed, and the resulting mixed solution is filtered through a membrane filter having a pore size of 0.2 μm to obtain a radiation-sensitive resin composition (J-1). Was prepared.

[Examples 8 to 13 and Comparative Examples 1 to 4]
Radiation-sensitive resin compositions were prepared in the same manner as in Example 7, except that the types and contents shown in Table 2 were used.

<Formation of resist pattern>
[Formation of resist pattern (1)] (ArF exposure, alkali development)
A spin coater (“CLEAN TRACK ACT12” manufactured by Tokyo Electron Co., Ltd.) is used to coat a lower antireflection film-forming composition (“ARC66” manufactured by Brewer Science Co., Ltd.) on a surface of a 12-inch silicon wafer, and then 205° C. By heating for 60 seconds, a lower antireflection film having a film thickness of 105 nm was formed. The radiation-sensitive resin composition prepared above was applied onto the lower antireflection film using the spin coater, and PB was performed at 90° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 second, and formed the resist film with a film thickness of 90 nm. Next, this resist film was subjected to an optical condition of NA=1.3 and dipole (Sigma 0.977/0.782) using an ArF excimer laser immersion exposure apparatus (“NSR-S610C” manufactured by NIKON). , 40 nm line and space (1L1S) mask pattern was used for exposure. After the exposure, PEB was performed at 100° C. for 60 seconds. Then, alkali development was performed using a 2.38 mass% TMAH aqueous solution as an alkali developing solution, washed with water, and dried to form a positive resist pattern. At the time of forming this resist pattern, the line width formed through a 1:1 line and space mask having a target size of 40 nm is the optimum exposure amount ( Eop).

[Formation of resist pattern (2)] (ArF exposure, organic solvent development)
In the above [Formation of resist pattern (1)], n-butyl acetate was used instead of the TMAH aqueous solution for organic solvent development, and washing with water was not carried out, and the above [Formation of resist pattern (1)] A negative resist pattern was formed in the same manner as in.

<Evaluation>
The LWR performance and MEEF performance of the radiation-sensitive resin composition were evaluated by measuring the formed resist pattern by the following method. A scanning electron microscope (“S-9380” manufactured by Hitachi High-Technologies Corporation) was used for measuring the length of the resist pattern.

[LWR performance]
The resist pattern formed by irradiating the exposure amount of Eop was observed from above the pattern using the scanning electron microscope. The line width was measured at a total of 50 points at arbitrary points, the 3 sigma value was determined from the distribution of the measured values, and this was taken as the LWR performance (nm). Regarding the LWR performance, the smaller the value, the smaller the rattling of the line and the better. The LWR performance can be judged to be good when it is 4 nm or less, and to be bad when it exceeds 4 nm.

[MEEF performance]
In the resist pattern resolved by irradiating the exposure dose of Eop, the line widths of the resist patterns respectively formed using the mask patterns having the line widths of 38 nm, 39 nm, 40 nm, 41 nm, and 42 nm are plotted on the vertical axis. The slope of the straight line when the size of the mask pattern was plotted on the horizontal axis was calculated and used as the MEEF performance. The MEEF performance shows that the closer the value is to 1, the better the mask reproducibility. When the MEEF performance is 3.2 or less, it can be evaluated as good, and when it exceeds 3.2, it can be evaluated as poor.

As can be seen from the results in Table 3, according to the radiation-sensitive resin composition of the example, excellent MEEF performance is exhibited in both alkali development and organic solvent development to form a resist pattern having a small LWR. be able to.

According to the radiation-sensitive resin composition and the method for forming a resist pattern of the present invention, since the polymer [A] has rigidity due to a specific structure, a resist pattern having a small LWR while exhibiting excellent MEEF performance. Can be formed. The polymer of the present invention can be suitably used as a polymer component of the radiation sensitive resin composition. According to the method for producing a compound of the present invention, a compound that gives the polymer can be easily produced with high yield. Therefore, these can be suitably used for manufacturing semiconductor devices and the like, which are expected to be further miniaturized in the future.

Claims (8)

A structural unit (I′) derived from a compound represented by the following formula (1′) and a structural unit (II) containing an acid dissociable group,
The content ratio of the structural unit (I′) is 15 mol% or more and 60 mol% or less based on all structural units constituting the polymer,
A polymer in which the content ratio of the structural unit (II) is 35 mol% or more and 70 mol% or less with respect to all structural units constituting the polymer.

(In the formula (1′), R ¹ is a monovalent group represented by the following formula (2-1) or (2-2). R ² is a substituted or unsubstituted C 1 to C 20 group. .R ³ and R ⁴ is a monovalent hydrocarbon radical of, be combined with each other to form a lactone structure composed ring members 3 to 20 together with the carbon atom or atoms chains they are attached.)

(In the formulas (2-1) and (2-2), L is a single bond or a divalent organic group having 1 to 20 carbon atoms. * is bonded to the oxygen atom of the formula (1′). Indicates the part.
In formula (2-1), R ⁵ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
In formula (2-2), R ⁶ is a hydrogen atom or a methyl group. R ⁷ , R ⁸ and R ⁹ are each independently a hydrogen atom, a halogen atom, a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms, or one or more R ⁷ and R ⁸ and Two or more of R ⁹ are combined with each other to form a ring structure with 3 to 20 ring members that is configured with the carbon atoms to which they are attached. a is an integer of 1 to 4. When a is 2 or more, a plurality of R ⁷ may be the same or different, and a plurality of R ⁸ may be the same or different. ) R in the above formula (1') ^Three And R ^Four The lactone structure having 3 to 20 ring members, which is combined with each other and is formed with a carbon atom or an atom chain to which these are bonded, is a butyrolactone structure, a valerolactone structure, a mevalonic lactone structure or a norbornane lactone structure. The polymers described. The polymer according to claim 1 or 2 , wherein L in the formulas (2-1) and (2-2) is a single bond. The polymer according to claim 1, 2 or 3 , wherein the structural unit (II) is represented by the following formula (3-1) or (3-2).

(In the formula ^{(3-1), R 12} is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group ^{.R 13} is a monovalent hydrocarbon group having 1 to 20 carbon atoms ^{.R 14} And R ¹⁵ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or an aliphatic group having 3 to 20 carbon atoms, which groups are combined with each other and are formed together with the carbon atom to which they are bonded. Represents a ring structure.
In formula (3-2), R ¹⁶ is a hydrogen atom or a methyl group. L ¹ is a single bond, —CCOO— or —CONH—. R ¹⁷ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ¹⁸ and R ¹⁹ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent oxyhydrocarbon group having 1 to 20 carbon atoms. ) Further having at least one structural unit (III) selected from the group consisting of a lactone structure other than the structural unit (I′), a cyclic carbonate structure and a sultone structure,
The polymer according to any one of claims 1 to 4, wherein the content ratio of the structural unit (III) is 5 mol% or more and 40 mol% or less based on all structural units constituting the polymer. The polymer according to any one of claims 1 to 5 , wherein the compound represented by the above formula (1') is represented by the following formula (i-5).

(In the formula (i-5), X ^is, C (R ³⁾ .R 3 and ^{R 4} is ^{-CO-R 4} is 'is synonymous with) .R ^6' above equation (1 is a hydrogen atom R ^7′ and R ^8′ are each independently a hydrogen atom, a halogen atom, a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms, or one or a plurality of R's. Two or more of ^7′ and R ^8′ are combined with each other to form a ring structure having 3 to 20 ring members which is configured with the carbon atom to which they are bonded, and a′ is an integer of 1 to 4. When a'is 2 or more, a plurality of R ⁷ 's may be the same or different, and a plurality of R ⁸ 's may be the same or different. Represented by the following formula (1′-a), which comprises a step of subjecting a compound represented by the following formula (a) and an acid halide represented by the following formula (b) to a dehydrohalogenation condensation reaction in the presence of a base. Of the compound to be prepared.

(In formulas (a), (b) and (1′-a), R ^1′ is a monovalent group represented by the following formula (2-1) or (2-2). R ² is , A substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, R ³ and R ⁴ are combined with each other and have 3 to 20 ring members which are configured with a carbon atom or an atom chain to which they are bonded. The lactone structure is formed , Z is —CO— or —SO ₂ —, and Y is a halogen atom.)

(In the formulas (2-1) and (2-2), L represents a single bond or a divalent organic group having 1 to 20 carbon atoms. * represents the above formulas (a) and (1′-a). The site that binds to Z is shown.
In formula (2-1), R ⁵ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
In formula (2-2), R ⁶ is a hydrogen atom or a methyl group. R ⁷ , R ⁸ and R ⁹ are each independently a hydrogen atom, a halogen atom, a hydroxy group or a monovalent organic group having 1 to 20 carbon atoms, or one or more R ⁷ and R ⁸ and Two or more of R ⁹ are combined with each other to form a ring structure with 3 to 20 ring members that is configured with the carbon atoms to which they are attached. a is an integer of 1 to 4. When a is 2 or more, a plurality of R ⁷ may be the same or different, and a plurality of R ⁸ may be the same or different. ) R in the above formulas (a) and (1'-a) ^Three And R ^Four The lactone structure having 3 to 20 ring members which is combined with each other and is formed with a carbon atom or an atom chain to which these are bonded is a butyrolactone structure, a valerolactone structure, a mevalonic lactone structure or a norbornane lactone structure. A method for producing the described compound.