JP6721839B2 - Radiation-sensitive resin composition, method for forming resist pattern, radiation-sensitive acid generator and compound - Google Patents

Description

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

The radiation-sensitive resin composition used for fine processing by lithography produces an acid in an exposed portion by irradiation with electromagnetic waves such as deep ultraviolet rays such as ArF excimer laser light and KrF excimer laser light, and charged particle beams such as electron beams. This acid-catalyzed chemical reaction causes a difference in the dissolution rate of the exposed portion and the unexposed portion with respect to the developing solution to form a resist pattern on the substrate.

The radiation-sensitive resin composition is required to have improved resolution and rectangularity of the cross-sectional shape of the resist pattern as the processing technology becomes finer. To meet this demand, the types and molecular structures of polymers, acid generators, and other components used in the composition have been investigated, and their combinations have also been studied in detail (Japanese Patent Laid-Open No. 11-125907, JP See Kaihei 8-146610 and Japanese Patent Laid-Open No. 2000-298347).

However, at the present time when the miniaturization of resist patterns has progressed to the level of line widths of 50 nm or less, the resolution and the rectangular shape of the resist pattern in cross section are not sufficiently satisfied. Further, the MEEF (Mask Error Enhancement Factor) performance, the LWR (Line Width Roughness) performance, the CD (Critical Dimension) uniformity, the depth of focus, and the exposure allowance, which are lithographic performance, are inconvenient with the above conventional acid generators.

Japanese Patent Laid-Open No. 11-125907 JP-A-8-146610 JP 2000-298347 A

The present invention has been made based on the above-described circumstances, and exhibits excellent MEEF performance, depth of focus and exposure latitude, and excellent LWR performance, CD uniformity, resolution, and cross-sectional shape. An object of the present invention is to provide a radiation-sensitive resin composition capable of forming a resist pattern having a rectangular shape.

The invention made to solve the above problems,
A polymer having a structural unit containing an acid dissociable group (hereinafter, also referred to as "[A] polymer"),
A compound consisting of a radiation-decomposable onium cation and a counter anion (hereinafter also referred to as "[B] compound"), and a solvent (hereinafter also referred to as "[G] solvent")
Containing
The counter anion has two or more carbonyl groups,
The radiation-sensitive resin composition has the above carbonyl groups bonded to each other through a single bond or a substituted or unsubstituted alkanediyl group having 1 to 10 carbon atoms.

The resist pattern forming method of the present invention is
A step of forming a resist film,
The method comprises the steps of exposing the resist film, and developing the exposed resist film,
The resist film is formed from the radiation sensitive resin composition.

（式（１−１）中、Ａは、炭素数１〜３０の１価の有機基である。Ｅ⁻は、ＳＯ_３ ⁻又はＣＯＯ⁻である。Ｘ^＋は、１価の放射線分解性オニウムカチオンである。Ｌは、単結合又は酸素原子である。Ｒ^１は、単結合又は炭素数１〜１０の置換又は非置換のアルカンジイル基である。Ｒ^２は、炭素数１〜２０の２価の有機基である。ｋは、１以上３以下の整数である。ｋが２以上の場合、複数のＲ^１は、同一でも異なっていてもよい。）

（式（１−２）中、Ａは、炭素数１〜３０の１価の有機基である。Ｅ⁻は、ＳＯ_３ ⁻又はＣＯＯ⁻である。Ｘ^＋は、１価の放射線分解性オニウムカチオンである。Ｒ^１は、単結合又は炭素数１〜１０の置換又は非置換のアルカンジイル基である。ｉは、０以上２以下の整数である。Ｒ^ｘは、炭素数１〜１０の置換又は非置換のアルカンジイル基である。Ｒ^０は、単結合又は炭素数１〜１９の２価の有機基である。ｉが２の場合、複数のＲ^１は、同一でも異なっていてもよい。）

（式（１−３）中、Ａは、炭素数１〜３０の１価の有機基である。Ｘ^＋は、１価の放射線分解性オニウムカチオンである。Ｒ^１は、炭素数１〜１０の置換又は非置換のアルカンジイル基である。） The radiation-sensitive acid generator of the present invention comprises a compound represented by the following formula (1-1), the following formula (1-2) or the following formula (1-3).

(In the formula (1-1), A is a monovalent organic group having 1 to 30 carbon atoms. E ⁻ is SO ₃ ⁻ or COO ⁻ . X ⁺ is a monovalent radiolytic onium. Is a cation, L is a single bond or an oxygen atom, R ¹ is a single bond or a substituted or unsubstituted alkanediyl group having 1 to 10 carbons, and R ² is 2 having 1 to 20 carbons. It is a valent organic group. k is an integer of 1 or more and 3 or less. When k is 2 or more, a plurality of R ^1's may be the same or different.)

(In the formula (1-2), A is a monovalent organic group having 1 to 30 carbon atoms. E ⁻ is SO ₃ ⁻ or COO ⁻ . X ⁺ is a monovalent radiolytic onium. C ¹ is a cation, R ¹ is a single bond or a substituted or unsubstituted alkanediyl group having 1 to 10 carbon atoms, i is an integer of 0 or more and 2 or less, and R ^x is 1 to 10 carbon atoms. It is a substituted or unsubstituted alkanediyl group, R ⁰ is a single bond or a divalent organic group having 1 to 19 carbon atoms, and when i is 2, a plurality of R ^1's may be the same or different. Good.)

(In the formula (1-3), A is a monovalent organic group having 1 to 30 carbon atoms. X ⁺ is a monovalent radiolytic onium cation. R ¹ is 1 to 10 carbon atoms. And a substituted or unsubstituted alkanediyl group.)

（式（１−１）中、Ａは、炭素数１〜３０の１価の有機基である。Ｅ⁻は、ＳＯ_３ ⁻又はＣＯＯ⁻である。Ｘ^＋は、１価の放射線分解性オニウムカチオンである。Ｌは、単結合又は酸素原子である。Ｒ^１は、単結合又は炭素数１〜１０の置換又は非置換のアルカンジイル基である。Ｒ^２は、炭素数１〜２０の２価の有機基である。ｋは、１以上３以下の整数である。ｋが２以上の場合、複数のＲ^１は、同一でも異なっていてもよい。）

（式（１−２）中、Ａは、炭素数１〜３０の１価の有機基である。Ｅ⁻は、ＳＯ_３ ⁻又はＣＯＯ⁻である。Ｘ^＋は、１価の放射線分解性オニウムカチオンである。Ｒ^１は、単結合又は炭素数１〜１０の置換又は非置換のアルカンジイル基である。ｉは、０以上２以下の整数である。Ｒ^ｘは、炭素数１〜１０の置換又は非置換のアルカンジイル基である。Ｒ^０は、単結合又は炭素数１〜１９の２価の有機基である。ｉが２の場合、複数のＲ^１は、同一でも異なっていてもよい。）

（式（１−３）中、Ａは、炭素数１〜３０の１価の有機基である。Ｘ^＋は、１価の放射線分解性オニウムカチオンである。Ｒ^１は、炭素数１〜１０の置換又は非置換のアルカンジイル基である。） The compound of the present invention is a compound represented by the following formula (1-1), the following formula (1-2) or the following formula (1-3).

(In the formula (1-1), A is a monovalent organic group having 1 to 30 carbon atoms. E ⁻ is SO ₃ ⁻ or COO ⁻ . X ⁺ is a monovalent radiolytic onium. Is a cation, L is a single bond or an oxygen atom, R ¹ is a single bond or a substituted or unsubstituted alkanediyl group having 1 to 10 carbons, and R ² is 2 having 1 to 20 carbons. It is a valent organic group. k is an integer of 1 or more and 3 or less. When k is 2 or more, a plurality of R ^1's may be the same or different.)

(In the formula (1-2), A is a monovalent organic group having 1 to 30 carbon atoms. E ⁻ is SO ₃ ⁻ or COO ⁻ . X ⁺ is a monovalent radiolytic onium. C ¹ is a cation, R ¹ is a single bond or a substituted or unsubstituted alkanediyl group having 1 to 10 carbon atoms, i is an integer of 0 or more and 2 or less, and R ^x is 1 to 10 carbon atoms. It is a substituted or unsubstituted alkanediyl group, R ⁰ is a single bond or a divalent organic group having 1 to 19 carbon atoms, and when i is 2, a plurality of R ^1's may be the same or different. Good.)

(In the formula (1-3), A is a monovalent organic group having 1 to 30 carbon atoms. X ⁺ is a monovalent radiolytic onium cation. R ¹ is 1 to 10 carbon atoms. And a substituted or unsubstituted alkanediyl group.)

Here, 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, excellent MEEF performance, depth of focus and exposure latitude are exhibited, and excellent LWR performance, CD uniformity, resolution and cross-sectional shape are achieved. A resist pattern having a rectangular shape can be formed. Therefore, these can be suitably used for a processing process of a semiconductor device which is expected to be further miniaturized in the future.

<Radiation-sensitive resin composition>
The radiation-sensitive resin composition contains a [A] polymer, a [B] compound and a [G] solvent. In addition, the radiation-sensitive resin composition has, as suitable components, a sulfonate compound (hereinafter, also referred to as “[C] other acid generator”) that generates an acid upon irradiation with radiation other than the [B] compound, [B]. ] An acid diffusion controller other than the compound (hereinafter, also referred to as "[D] other acid diffusion controller") and a fluorine atom-containing polymer (hereinafter, also referred to as "[E] fluorine atom-containing polymer") May be contained, and other optional components may be contained within a range not impairing the effects of the present invention. Hereinafter, each component will be described.

<[A] polymer>
The polymer [A] is a polymer having a structural unit containing an acid dissociable group. According to the radiation-sensitive resin composition, the acid generated from the compound [B] or the like dissociates the acid-dissociable group of the polymer [A] in the exposed area with respect to the developer in the exposed area and the unexposed area. A difference in solubility occurs, and as a result, a resist pattern can be formed. The “acid-dissociable group” means a group that substitutes a hydrogen atom such as a carboxy group and a hydroxy group and dissociates by the action of an acid. The polymer [A] is not particularly limited as long as it has an acid dissociable group. The acid dissociable group may be present anywhere in the main chain, side chain, terminal or the like of the polymer [A]. The polymer [A] has the following formula (5-1) and formula (5-2) described below, in addition to the structural unit having an acid dissociable group (hereinafter, also referred to as “structural unit (I)”). At least one selected from the group consisting of structural units represented (hereinafter, also referred to as “structural unit (II)”), a structural unit represented by the following formula (6) (hereinafter referred to as “structural unit (III)”). Also referred to as “”) and other structural units other than the above structural units (I) to (III). The polymer [A] may have one type or two or more types of each structural unit. Hereinafter, each structural unit will be described.

[Structural unit (I)]
The structural unit (I) is a structural unit containing an acid dissociable group. As the structural unit (I), for example, a structural unit represented by the following formula (3-1) (hereinafter, also referred to as “structural unit (I-1)”) and a following formula (3-2). Structural units (hereinafter, also referred to as “structural unit (I-2)”) and the like can be mentioned.

In the above formula (3-1), R ⁶ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Y ¹ is a monovalent acid dissociable group.
In the above formula (3-2), R ⁷ is a hydrogen atom or a methyl group. Y ² is a monovalent acid dissociable group.

From the viewpoint of the copolymerizability of the monomer giving the structural unit (I-1), R ⁶ is preferably a hydrogen atom or a methyl group, more preferably a methyl group.

The monovalent acid-dissociable group represented by Y ^1, preferably a group represented by the following formula (Y-1).

In the above formula (Y-1), R ^e1 is a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or an alicyclic hydrocarbon group having 3 to 20 carbon atoms. R ^e2 and R ^e3 are each independently a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or these groups. Represents an alicyclic structure having 3 to 20 ring carbon atoms which are combined with each other and are formed together with the carbon atoms to which they are bonded.

Examples of the monovalent chain hydrocarbon group having 1 to 10 carbon atoms represented by the above R ^e1 , R ^e2 and R ^e3 include, for example,
Alkyl groups such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-pentyl group;
Alkenyl groups such as ethenyl group, propenyl group, butenyl group, pentenyl group;
Examples thereof include alkynyl groups such as ethynyl group, propynyl group, butynyl group and pentynyl group.

Among these, an alkyl group is preferable, an alkyl group having 1 to 4 carbon atoms is more preferable, a methyl group, an ethyl group and an i-propyl group are further preferable, and an ethyl group is particularly preferable.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ^e1 , R ^e2 and R ^e3 include, for example,
Monocyclic cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclooctyl group;
Polycyclic cycloalkyl groups such as norbornyl group, adamantyl group, tricyclodecyl group, tetracyclododecyl group;
A monocyclic cycloalkenyl group such as cyclopropenyl group, cyclobutenyl group, cyclopentenyl group, cyclohexenyl group;
Examples thereof include polycyclic cycloalkenyl groups such as norbornenyl group and tricyclodecenyl group.

Among these, a monocyclic cycloalkyl group and a polycyclic cycloalkyl group are preferable, and a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group are more preferable.

Examples of the alicyclic structure having 3 to 20 ring members formed by combining these groups with each other include, for example,
A monocyclic cycloalkane structure such as a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, or a cyclooctane structure;
A polycyclic cycloalkane structure such as a norbornane structure, an adamantane structure, a tricyclodecane structure or a tetracyclododecane structure;
A monocyclic cycloalkene structure such as a cyclopropene structure, a cyclobutene structure, a cyclopentene structure, a cyclohexene structure or a cyclooctene structure;
Examples thereof include polycyclic cycloalkene structures such as norbornene structure, tricyclodecene structure and tetracyclododecene structure.

Among these, a monocyclic cycloalkane structure and a polycyclic cycloalkane structure are preferable, a monocyclic cycloalkane structure having 5 to 8 carbon atoms and a polycyclic cycloalkane structure having 7 to 12 carbon atoms are more preferable, and Pentane structure, cyclohexane structure, cyclooctane structure, norbornane structure and adamantane structure are more preferable, and cyclopentane structure and adamantane structure are particularly preferable.

As the group represented by the above formula (Y-1), R ^e1 is a monovalent chain hydrocarbon group having 1 to 10 carbon atoms, and R ^e2 and R ^e3 are combined with each other and bonded to each other. It is preferable to represent an alicyclic structure having 3 to 20 ring members which is formed together with an atom, R ^e1 is an alkyl group having 1 to 10 carbon atoms, and R ^e2 and R ^e3 are combined with each other and a carbon atom to which these are bonded. It is more preferable to represent a cycloalkane structure having 3 to 20 ring members constituted by R ^e1 , R ^e1 is an alkyl group having 1 to 4 carbon atoms, and R ^e2 and R ^e3 are combined with each other and a carbon atom to which these are bonded. It is more preferable to represent a monocyclic cycloalkane structure having 5 to 8 ring members or a polycyclic cycloalkane structure having 7 to 12 ring carbon atoms.

From the viewpoint of the copolymerizability of the monomer giving the structural unit (I-2), R ⁷ is preferably a hydrogen atom.

The monovalent acid-dissociable group represented by Y ^2, preferably a group represented by the following formula (Y-2).

In the above formula (Y-2), R ^e4 , R ^e5 and R ^e6 are each independently a hydrogen atom, a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, or a monovalent having 3 to 20 carbon atoms. Is an alicyclic hydrocarbon group, an oxy chain hydrocarbon group having 1 to 20 carbon atoms, or an oxyalicyclic hydrocarbon group having 1 to 20 carbon atoms. However, R ^e4 , R ^e5, and R ^e6 are not simultaneously hydrogen atoms.

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms represented by R ^e4 , R ^e5, and R ^e6 include, for example,
Alkyl groups such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-pentyl group;
Alkenyl groups such as ethenyl group, propenyl group, butenyl group, pentenyl group;
Examples thereof include alkynyl groups such as ethynyl group, propynyl group, butynyl group and pentynyl group.

Among these, an alkyl group is preferable, an alkyl group having 1 to 4 carbon atoms is preferable, a methyl group, an ethyl group and an n-propyl group are more preferable, and a methyl group is particularly preferable.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms and represented by R ^e4 , R ^e5, and R ^e6 include the same groups as those exemplified as the above R ^e1 , R ^e2, and R ^e3. Etc.

Among these, a monocyclic cycloalkyl group and a polycyclic cycloalkyl group are preferable, and a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group are more preferable.

Examples of the monovalent oxy-chain hydrocarbon group having 1 to 20 carbon atoms represented by R ^e4 , R ^e5, and R ^e6 include, for example,
Alkoxy groups such as methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, i-butoxy group, sec-butoxy group, t-butoxy group, n-pentyloxy group;
Alkenyloxy groups such as ethenyloxy group, propenyloxy group, butenyloxy group, pentenyloxy group;
Examples thereof include an alkynyloxy group such as an ethynyloxy group, a propynyloxy group, a butynyloxy group and a pentynyloxy group.

Among these, an alkoxy group is preferable, an alkoxy group having 1 to 4 carbon atoms is preferable, and a methoxy group, an ethoxy group, and an n-propoxy group are more preferable.

Examples of the monovalent oxyalicyclic hydrocarbon group having 3 to 20 carbon atoms represented by the above R ^e4 , R ^e5 and R ^e6 include, for example,
A monocyclic cycloalkyloxy group such as a cyclopropyloxy group, a cyclobutyloxy group, a cyclopentyloxy group, a cyclohexyloxy group, a cyclooctyloxy group;
A polycyclic cycloalkyloxy group such as a norbornyloxy group, an adamantyloxy group, a tricyclodecyloxy group, a tetracyclododecyloxy group;
A monocyclic cycloalkenyloxy group such as a cyclopropenyloxy group, a cyclobutenyloxy group, a cyclopentenyloxy group, a cyclohexenyloxy group;
Examples thereof include polycyclic cycloalkenyloxy groups such as norbornenyloxy group and tricyclodecenyloxy group.

Among these, a monocyclic cycloalkyloxy group and a polycyclic cycloalkyloxy group are preferable, and a cyclopentyloxy group, a cyclohexyloxy group, a norbornyloxy group, and an adamantyloxy group are more preferable.

As the group represented by the above formula (Y-2), R ^e4 , R ^e5 and R ^e6 are monovalent chain hydrocarbon groups, and R ^e4 and R ^e5 are monovalent chain hydrocarbon groups. A group in which R ^e6 is a monovalent oxy chain hydrocarbon group, R ^e4 is a monovalent chain hydrocarbon group, and R ^e5 and R ^e6 are monovalent oxy chain hydrocarbon groups are preferable, A group in which R ^e4 , R ^e5 and R ^e6 are alkyl groups, a group in which R ^e4 and R ^e5 are alkyl groups and R ^e6 is an alkoxy group, a group in which R ^e4 is an alkyl group and R ^e5 and R ^e6 are alkoxy groups Is more preferable, and a group in which R ^e4 , R ^e5, and R ^e6 are alkyl groups is further preferable, and t-butyl group, t-pentyl group, t-hexyl group, and t-heptyl group are particularly preferable.

As the structural unit (I), for example,
As the structural unit (I-1), structural units represented by the following formulas (3-1-1) to (3-1-7), and the like;
Examples of the structural unit (I-2) include structural units represented by the following formulas (3-2-1) to (3-2-3).

In the formulas (3-1-1) to (3-1-7), R ⁶ has the same meaning as in the formula (3-1). R ^e1 , R ^e2 and R ^e3 have the same ^{meaning as} in the above formula (Y-1). Each r is independently an integer of 1 to 3.
In the above formulas (3-2-1) to (3-2-3), R ⁷ has the same meaning as in the above formula (3-2).

As the structural unit (I), the structural unit (I-1) is preferable, and the structural unit represented by the formula (3-1-2), the structural unit represented by the formula (3-1-3), The structural unit represented by the formula (3-1-4) and the structural unit represented by the formula (3-1-5) are more preferable, and the structural unit containing a cyclopentane structure and the structural unit containing an adamantane structure are More preferred are structural units containing a 1-ethyl-1-cyclopentyl group, a 2-ethyl-2-adamantyl group, and a 2-methyl-2-adamantyl group.

The content ratio of the structural unit (I) is preferably 10 mol% to 70 mol%, more preferably 20 mol% to 60 mol%, and further preferably 30 mol% with respect to all structural units constituting the [A] polymer. ˜55 mol% is more preferred, and 35 mol% to 50 mol% is particularly preferred. By setting the content ratio of the structural unit (I) in the above range, LWR performance, CD uniformity, resolution, rectangularity of cross-sectional shape, MEEF performance, depth of focus and exposure latitude of the radiation-sensitive resin composition. (Hereinafter, also referred to as “LWR performance etc.”) is more excellent.

[Structural unit (II)]
The structural unit (II) is a structural unit represented by the following formula (5-1) (hereinafter, also referred to as “structural unit (II-1)”) and a structural unit represented by the following formula (5-2) ( Hereinafter, at least one kind selected from the group consisting of "structural unit (II-2)"). When the polymer [A] has the structural unit (II), the dispersibility of the compound [B] and the other acid generator [C] in the polymer [A] can be improved. As a result, the radiation-sensitive resin composition is more excellent in LWR performance and the like. Further, the adhesion of the resist pattern formed from the radiation-sensitive resin composition to the substrate can be improved.

In the above formula (5-1), R ⁸ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. E ¹ is a single bond, —COO— or CO—O—(CH ₂ ) _i . i is an integer of 1 to 6. R ⁹ is a group that is non-acid dissociable and contains a polar group.
In the above formula (5-2), R ^8′ is a hydrogen atom or a methyl group. R ^a and R ^b are each independently a hydrogen atom, a fluorine atom, a hydroxy group or a monovalent organic group. s is an integer of 1 to 3. When s is 2 or more, a plurality of R ^a and R ^b may be the same or different. R ^9a and R ^9b are each independently a hydrogen atom, a fluorine atom, a hydroxy group or a monovalent organic group, or R ^9a and R ^9b are combined with each other and are composed of a carbon atom to which they are bonded. It represents a ring structure having 3 to 30 ring members.

In the structural unit (II-1),
From the viewpoint of the copolymerizability of the monomer giving the structural unit (II-1), R ⁸ is preferably a hydrogen atom or a methyl group, and more preferably a methyl group.

From the viewpoint of the copolymerizability of the monomer giving the structural unit (II-1), CO is preferable as the E ¹ .

The polar group in the non-acid dissociable and polar group-containing group represented by R ⁹ is, for example, a monovalent group (a) such as a hydroxy group, a carboxy group, a cyano group, a sulfo group or a mercapto group; Examples thereof include a carbonyl group, O, S, and a divalent group (b) formed by combining these.

Examples of the group containing a non-acid dissociable and polar group represented by R ⁹ include, for example, a part or all of the hydrogen atoms of a monovalent hydrocarbon group having 1 to 20 carbon atoms as described above for the monovalent group ( a group substituted with a), a group containing the above divalent group (b) between some or all of the carbon-carbon monovalent hydrocarbon groups having 1 to 20 carbons, monovalent having 1 to 20 carbons A group in which a part or all of the hydrogen atoms of the hydrocarbon group of is substituted with the above monovalent group (a) and which contains the above divalent group (b) between some or all of the carbon-carbon groups. Can be mentioned.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and carbon. Examples include monovalent aromatic hydrocarbon groups having a number of 6 to 20.
Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include the same groups as those exemplified as R ^e4 , R ^e5 and R ^e6 in the above formula (Y-2).
Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include the same groups as those exemplified as R ^e1 , R ^e2 and R ^e3 in the above formula (Y-1).
Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include aryl groups such as phenyl group, tolyl group, xylyl group, mesityl group, naphthyl group, methylnaphthyl group, anthryl group and methylanthryl group;
Examples thereof include aralkyl groups such as benzyl group, phenethyl group, naphthylmethyl group, and anthrylmethyl group.

Examples of R ⁹ include a group having a lactone structure, a group having a cyclic carbonate structure, a group having a sultone structure, and a group having a hydroxy group.

Examples of the group having a lactone structure include a butyrolactone-yl group, a norbornane lactone-yl group, a 5-oxo-4-oxatricyclo[4.3.1.1 ^3,8 ]undecane-yl group, and the like. To be
Examples of the group having a cyclic carbonate structure include an ethylene carbonate-ylmethyl group.
Examples of the group having a sultone structure include a group having a sultone structure such as a propane sultone-yl group and a norbornane sultone-yl group.
Examples of the group having a hydroxy group include a hydroxyadamantyl group, a dihydroxyadamantyl group, a trihydroxyadamantyl group, a hydroxyethyl group and the like.

In the structural unit (II-2),
From the viewpoint of the copolymerizability of the monomer that gives the structural unit (II-2), R ^8′ is preferably a hydrogen atom.

Examples of the monovalent organic group represented by R ^a , R ^b , R ^9a and R ^9b include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms and a monovalent chain having 3 to 20 carbon atoms. An alicyclic hydrocarbon group, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a group in which some or all of the hydrogen atoms of these groups are substituted with a substituent, and the carbon-carbon group of these groups Include CO, CS, O, S, or NR′, or a group containing a group in which two or more of these are combined. R'is a hydrogen atom or a monovalent organic group.

Examples of the ring structure having 3 to 30 ring members in which R ^9a and R ^9b are combined with each other and are combined with the carbon atom to which they are bonded include, for example, cyclopropane structure, cyclobutane structure, cyclopentane structure, cyclohexane structure, norbornane structure, Alicyclic structures such as adamantane structure; aliphatic heterocyclic structures such as oxacyclopentane structure, thiacyclopentane structure and azacyclopentane structure.

As s, 1 or 2 is preferable and 1 is more preferable.

As the structural unit (II), for example,
Structural units represented by the following formulas (5-1-1) to (5-1-11) as the structural unit (II-1) and the like;
Examples of the structural unit (II-2) include structural units represented by the following formulas (5-2-1) and (5-2-2).

In the above formulas (5-1-1) to (5-1-11), R ⁸ has the same meaning as in the above formula (5-1).
In the formulas (5-2-1) and (5-2-2), R ^8′ has the same meaning as in the formula (5-2).

Among these, the structural units represented by the above formulas (5-1-1), (5-1-3), (5-1-8) and (5-1-11) are preferable.

The content ratio of the structural unit (II) is preferably 0 mol% to 70 mol%, more preferably 10 mol% to 60 mol%, and more preferably 20 mol% with respect to all structural units constituting the polymer [A]. ˜50 mol% is more preferred. By setting the content ratio of the structural unit (II) in the above range, the dispersibility of the [B] compound, [C] and other acid generators in the [A] polymer is further improved, and as a result, the radiation-sensitive material The LWR performance of the resin composition is more excellent.

[Structural unit (III)]
The structural unit (III) is a structural unit represented by the following formula (6). When KrF excimer laser light, EUV, electron beam, or the like is used as the irradiation radiation, the radiation-sensitive resin composition has the structural unit (III) in the polymer [A] to enhance the sensitivity. be able to.

In the above formula (6), R ¹⁰ is a hydrogen atom or a methyl group. R ¹¹ is a monovalent organic group having 1 to 20 carbon atoms. p is an integer of 0-3. If R ¹¹ is plural, plural R ¹¹ may be the same or different. q is an integer of 1 to 3. However, p and q satisfy p+q≦5.

From the viewpoint of the copolymerizability of the monomer giving the structural unit (III), R ¹⁰ is preferably a hydrogen atom.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ¹¹ include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms and a monovalent alicyclic group having 3 to 20 carbon atoms. A hydrocarbon group, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a group in which a part or all of the hydrogen atoms of these groups are substituted with a substituent, a carbon-carbon bond between these groups , CS, O, S or NR″, or a group containing a group in which two or more of these are combined. R″ is a hydrogen atom or a monovalent organic group.
Among these, a monovalent chain hydrocarbon group is preferable, an alkyl group is more preferable, and a methyl group is further preferable.

As said p, the integer of 0-2 is preferable, 0 or 1 is more preferable, and 0 is further more preferable.

1 or 2 is preferable and, as for said q, 1 is more preferable.

Examples of the structural unit (III) include structural units represented by the following formulas (6-1) to (6-4).

In the formulas (6-1) to (6-4), R ¹⁰ has the same meaning as in the formula (6).

Among these, the structural units represented by the above formulas (6-1) and (6-2) are preferable, and the structural units represented by the above formula (6-1) are more preferable.

The content ratio of the structural unit (III) is preferably 0 mol% to 90 mol%, more preferably 30 mol% to 80 mol%, and further preferably 50 mol% with respect to all structural units constituting the polymer [A]. ˜75 mol% is more preferred. By setting the content ratio of the structural unit (III) within the above range, the radiation-sensitive resin composition can further improve the sensitivity.

The structural unit (III) is obtained by polymerizing a monomer obtained by substituting the hydrogen atom of the OH group of hydroxystyrene with a t-butyl group or the like, and then subjecting the obtained polymer to a hydrolysis reaction in the presence of an amine. It can be formed by things.

[Other structural units]
The polymer [A] may have a structural unit other than the structural units (I) to (III). Examples of the other structural unit include a structural unit derived from a (meth)acrylic acid ester containing a non-dissociable monovalent alicyclic hydrocarbon group. The content ratio of the other structural unit is preferably 20 mol% or less, more preferably 10 mol% or less, based on all structural units constituting the polymer [A].

<Method of synthesizing [A] polymer>
The polymer [A] can be synthesized by a conventional method such as radical polymerization. For example, a method of dropping a solution containing a monomer and a radical initiator into a reaction solvent or a solution containing a monomer to cause a polymerization reaction, a solution containing a monomer and a solution containing a radical initiator, Separately, a method of carrying out a polymerization reaction by dropping into a solution containing a reaction solvent or a monomer, a reaction solvent containing a plurality of kinds of solutions containing each monomer and a solution containing a radical initiator, or a single amount It is preferable to synthesize by a method of dropping a solution containing a polymer to carry out a polymerization reaction, a method of carrying out a polymerization reaction of a solution containing a monomer and a radical initiator in a solvent or a reaction solvent, and the like.

When the monomer solution is dropped and reacted with the monomer solution, the amount of the monomer in the dropped monomer solution is 30 mol based on the total amount of the monomers used for the polymerization. % Or more, preferably 50 mol% or more, more preferably 70 mol% or more.

The reaction temperature in these methods may be appropriately determined depending on the type of initiator. It is usually 30°C to 150°C, preferably 40°C to 150°C, and more preferably 50°C to 140°C. The dropping time varies depending on the reaction temperature, the type of initiator, the monomer to be reacted, etc., but is usually 30 minutes to 8 hours, preferably 45 minutes to 6 hours, more preferably 1 hour to 5 hours. Further, the total reaction time including the dropping time also varies depending on the conditions similarly to the dropping time, but is usually 30 minutes to 12 hours, preferably 45 minutes to 12 hours, more preferably 1 to 10 hours.

Examples of the radical initiator used in the above polymerization include azobisisobutyronitrile (AIBN), 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis. (2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2'-azobis(2-methylpropionate), dimethyl 2,2'-azobis Azo radical initiators such as isobutyrate; peroxide radical initiators such as benzoyl peroxide, t-butyl hydroperoxide and cumene hydroperoxide. Of these, AIBN and dimethyl 2,2'-azobis(2-methylpropionate) are preferable. In addition, you may use a radical initiator individually or in combination of 2 or more types.

As the reaction solvent, a solvent other than a solvent that inhibits polymerization (nitrobenzene having a polymerization inhibiting effect, a mercapto compound having a chain transfer effect, etc.) and a solvent capable of dissolving the monomer may be used. it can. Examples thereof include alcohols, ethers, ketones, amides, esters/lactones, nitriles and mixed solvents thereof. You may use these solvent individually or in combination of 2 or more types.

The polymer obtained by the polymerization reaction is preferably recovered by the reprecipitation method. That is, after the completion of the polymerization reaction, the target polymer is recovered as a powder by introducing the polymerization solution into the reprecipitation solvent. As the reprecipitation solvent, alcohols, alkanes and the like may be used alone or in combination of two or more kinds. In addition to the reprecipitation method, the polymer can also be recovered by removing low molecular components such as monomers and oligomers by a liquid separation operation, a column operation, an ultrafiltration operation, or the like.

The polystyrene-equivalent weight average molecular weight (Mw) of the polymer [A] by gel permeation chromatography (GPC) is preferably 1,000 to 50,000, more preferably 2,000 to 40,000, and 3,000 to. 30,000 is more preferable, and 5,000 to 20,000 is particularly preferable. When the Mw of the polymer [A] is less than the above lower limit, the heat resistance of the resist pattern formed from the radiation-sensitive resin composition may decrease. When the Mw of the polymer [A] exceeds the above upper limit, the developability of the radiation-sensitive resin composition may decrease.

The ratio (Mw/Mn, dispersity) of Mw to polystyrene-reduced number average molecular weight (Mw) by GPC of the polymer [A] is preferably 1 to 5, more preferably 1 to 3, and 1 to 2.5. More preferable.

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

<[B] compound>
The compound [B] is a compound composed of a radiation-decomposable onium cation and a counter anion, wherein the counter anion has two or more carbonyl groups, and the carbonyl groups are single bonds or have 1 to 10 carbon atoms. It is a compound that binds via a substituted or unsubstituted alkanediyl group. Since the radiation-sensitive resin composition contains the compound [B], the LWR performance and the like are excellent.

The reason why the radiation-sensitive resin composition contains the [B] compound having the specific structure to achieve the above effect can be inferred as follows, for example. That is, the counter anion of the compound [B] has a specific structure in which two or more carbonyl groups are located near each other. Therefore, the interaction between the acid obtained by binding the proton generated by exposure to the counter anion of the [B] compound and the [A] polymer in the resist film is increased, and the diffusion length of the acid is appropriately controlled. It is conceivable that the acid diffusion can be suppressed uniformly by the uniform distribution in the resist film.

As the compound [B], a compound represented by the following formula (1-1) is preferable. Since the radiation-sensitive resin composition contains the [B] compound represented by the following formula (1-1), the LWR performance and the like are more excellent.

In the above formula (1-1), A is a monovalent organic group having 1 to 30 carbon atoms. E ⁻ is SO ₃ ⁻ or COO ⁻ . X ⁺ is a monovalent radiolytic onium cation. L is a single bond or an oxygen atom. R ¹ is a single bond or a substituted or unsubstituted alkanediyl group having 1 to 10 carbon atoms. R ² is a divalent organic group having 1 to 20 carbon atoms. k is an integer of 1 or more and 3 or less. When k is 2 or more, a plurality of R ¹ may be the same or different.

As L in the above formula (1-1), an oxygen atom is preferable. The radiation-sensitive resin composition is further excellent in LWR performance and the like by containing such a [B] compound having a specific structure.

As the compound [B], a compound represented by the following formula (1-2) is also preferable. When the radiation-sensitive resin composition contains the [B] compound represented by the following formula (1-2), the LWR performance and the like are more excellent.

In the above formula (1-2), A is a monovalent organic group having 1 to 30 carbon atoms. E ⁻ is SO ₃ ⁻ or COO ⁻ . X ⁺ is a monovalent radiolytic onium cation. R ¹ is a single bond or a substituted or unsubstituted alkanediyl group having 1 to 10 carbon atoms. i is an integer of 0 or more and 2 or less. R ^x is a substituted or unsubstituted alkanediyl group having 1 to 10 carbon atoms. R ⁰ is a single bond or a divalent organic group having 1 to 19 carbon atoms. When i is 2, a plurality of R ¹ may be the same or different.

As the compound [B], a compound represented by the following formula (1-3) is also preferable. When the radiation-sensitive resin composition contains the [B] compound represented by the following formula (1-3), the LWR performance and the like are more excellent.

In the above formula (1-3), A is a monovalent organic group having 1 to 30 carbon atoms. X ⁺ is a monovalent radiolytic onium cation. R ¹ is a substituted or unsubstituted alkanediyl group having 1 to 10 carbon atoms.

As the compound [B], in the formula (1-1) or (1-2), E ⁻ is SO ₃ ⁻ , and a fluorine atom or a fluorinated alkyl group is bonded to a carbon atom adjacent to E ^−. A compound (hereinafter, also referred to as “[B1] compound”) or a compound represented by the above formula (1-3), E ⁻ is SO ₃ ⁻ , and a fluorine atom is bonded to a carbon atom adjacent to E ^−. Examples thereof include compounds that are not used or compounds in which E ⁻ is COO ⁻ (hereinafter, also referred to as “[B2] compound”). The [B1] compound functions as an acid generator, and the [B2] compound functions as an acid diffusion controller or, when the PEB temperature is relatively high, as an acid generator.

Examples of the monovalent organic group having 1 to 30 carbon atoms represented by A include a monovalent hydrocarbon group having 1 to 30 carbon atoms, and -O at the carbon-carbon or bond-hand end of the hydrocarbon group. Examples thereof include a group containing a hetero atom-containing group such as -, -S-, -N-, -CO-, and -COO-.

Among these, A is -NRR, -OR or -R, wherein R is a substituted or unsubstituted chain hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted 3 to 30 ring member. An alicyclic hydrocarbon group, an aliphatic heterocyclic group having 3 to 30 ring members, and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring members are preferable.

Moreover, as said A, the group containing -COO- between carbon-carbon of the said substituted or unsubstituted C3-C30 alicyclic hydrocarbon group is also preferable. Incidentally, in -NRR, two Rs may be the same or different.

Examples of the chain hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group and the like.

As the alicyclic hydrocarbon group, for example,
Monocyclic cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclooctyl group;
A monocyclic cycloalkenyl group such as a cyclobutenyl group, a cyclopentenyl group or a cyclohexenyl group;
Polycyclic cycloalkyl groups such as norbornyl group, adamantyl group, tricyclodecyl group, tetracyclododecyl group;
Examples thereof include polycyclic cycloalkenyl groups such as norbornenyl group, tricyclodecenyl group, and tetracyclododecenyl group.

As the aliphatic heterocyclic group, for example,
A group containing a lactone structure such as a norbornane lactone-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;
A nitrogen atom-containing heterocyclic group such as an azacycloheptyl group and a diazabicyclooctane-yl group;
Examples thereof include sulfur atom-containing heterocyclic groups such as thiacycloheptyl group and thianorbornyl group.

Examples of the aromatic hydrocarbon group include:
Examples thereof include an aryl group such as a phenyl group, a tolyl group, a xylyl group, a mesityl group, and a naphthyl group; and an aralkyl group such as a benzyl group and a phenethyl group.

The chain hydrocarbon group, an alicyclic hydrocarbon group or a substituent that may substitute the hydrogen atom of the aromatic hydrocarbon group, an alkyl group, an alkoxy group, an aryloxy group, an acyl group, an acyloxy group, Examples thereof include a hydroxy group, a carboxy group, an amino group, a cyano group, a nitro group and a sulfonamide group. Of these, a linear or branched alkyl group having 1 to 5 carbon atoms, a phenoxy group, and a hydroxy group are preferable.

Among these, A is preferably a cycloalkyl group, a group having a lactone structure, a cycloalkyloxy group, a cycloalkylamino group, a cycloalkylsulfanyl group, a hydroxyaryloxy group or an aryloxyalkyl group.

SO ₃ ⁻ is preferable as E ⁻ .

As k in the above formula (1-1), 1 and 2 are preferable, and 1 is more preferable. However, when k is 3, 4 or more —C(O)— are not continuously bonded.

Among the substituted or unsubstituted alkanediyl groups having 1 to 10 carbon atoms of R ¹ , examples of the unsubstituted alkanediyl groups include, for example, methanediyl group, ethanediyl group, propanediyl group, and the like. Are listed. Of these, a methanediyl group and a propane-2,2-diyl group are preferable. The substituted alkanediyl group is a group in which some or all of the hydrogen atoms bonded to the same carbon atom of the alkanediyl group are substituted with a divalent organic group, or hydrogen atoms bonded to different carbon atoms of the alkanediyl group. And a group in which a part or all of is substituted with a monovalent group. As the divalent organic group substituting the same carbon atom of the alkanediyl group, a divalent organic group having a lactone structure, a divalent organic group having a cyclic carbonate structure and a divalent organic group having a sultone structure are preferable. The valerolactone-diyl group is more preferred. The monovalent group substituting a part or all of the hydrogen atoms bonded to different carbon atoms of the alkanediyl group is preferably a fluorine atom or a fluorinated alkyl group, more preferably a fluorine atom.

As R ¹ , a single bond is also preferable.

The divalent organic group having 1 to 20 carbon atoms represented by R ² in the above formula (1-1) is a group represented by the following formula (2) or a group represented by the following formula (2′). Etc. Of these, a group represented by the following formula (2) is preferable.

In the above formula (2), R ³ and R ⁴ are each independently a hydrogen atom or a monovalent organic group. Rf ¹ and Rf ² are each independently a fluorine atom or a fluorinated alkyl group. n is an integer of 1 or more and 6 or less. m is an integer of 0 or more and 6 or less. *1 indicates a site that binds to L or an oxygen atom.

In the above formula (2′), R ^y is a substituted or unsubstituted alkanediyl group having 2 to 10 carbon atoms. Rf ¹ and Rf ² are each independently a fluorine atom or a fluorinated alkyl group. n is an integer of 1 or more and 6 or less. m is an integer of 0 or more and 6 or less. *1 indicates a site that binds to L or an oxygen atom.

Examples of the monovalent organic group represented by R ³ and R ⁴ include a chain hydrocarbon group.

As R ³ and R ⁴ , a hydrogen atom is preferable.

Among the substituted or unsubstituted alkanediyl groups having 2 to 10 carbon atoms represented by R ^y , examples of the unsubstituted alkanediyl group include, for example, ethanediyl group, propanediyl group, and other alkanes having 1 to 10 carbon atoms. A diyl group is mentioned. As the substituent, for example, a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, a carboxy group, a cyano group, a nitro group, an alkoxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, an acyl group, Examples thereof include an acyloxy group.

As n in the above formulas (2) and (2'), 2 or more and 4 or less are preferable.

As the fluorinated alkyl group represented by Rf ¹ and Rf ² in the above formulas (2) and (2′), a trifluoromethyl group is preferable.

As m in the above formulas (2) and (2'), 0 or more and 2 or less is preferable.

As i in the above formula (1-2), 0 is preferable.

Among the substituted or unsubstituted alkanediyl groups having 1 to 10 carbon atoms represented by R ^x in the above formula (1-2), the unsubstituted alkanediyl group is, for example, methanediyl group, ethanediyl group, propanediyl group. Examples thereof include alkanediyl groups having 1 to 10 carbon atoms such as groups. As the substituent, for example, a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, a carboxy group, a cyano group, a nitro group, an alkoxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, an acyl group, Examples thereof include an acyloxy group.

Of these, a methanediyl group is preferable as R ^x .

Examples of the divalent organic group having 1 to 19 carbon atoms of R ⁰ in the above formula (1-2) include the same groups as those exemplified as R ² in the above formula (1-1).

The monovalent radiolytic onium cation represented by X ⁺ is a cation that decomposes by the action of radiation. In the exposed area, a sulfonic acid is produced from the proton generated by the decomposition of the radiation-decomposable onium cation and the sulfonate anion of the [B] compound. Examples of the monovalent radiation-decomposable onium cation represented by X ⁺ include a sulfonium cation, a tetrahydrothiophenium cation, and an iodonium cation. Among these, a sulfonium cation represented by the following formula (X-0), a sulfonium cation represented by the following formula (X-1), and an iodonium cation represented by the following formula (X-2) are preferable.

In the above formula (X-0), R ^{b4 to} R ^b6 each independently represent an aliphatic hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or 10 carbon atoms. The aromatic hydrocarbon group of 36 may be represented, or R ^b4 and R ^b5 may be combined with each other to form a 3-membered to 12-membered ring containing a sulfur atom. The hydrogen atom contained in the aliphatic hydrocarbon group is a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alicyclic saturated hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. May be substituted with, and the hydrogen atom contained in the alicyclic hydrocarbon group is substituted with a halogen atom, an alkyl group having 1 to 18 carbon atoms, an acyl group having 2 to 4 carbon atoms, or a glycidyloxy group. Alternatively, the hydrogen atom contained in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxy group or an alkoxy group having 1 to 12 carbon atoms.

Examples of the aliphatic hydrocarbon group in the above formula (X-0) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group. Group, octyl group, 2-ethylhexyl group and the like. The carbon number of the aliphatic hydrocarbon group of R ^{b4 to} R ^b6 is preferably 1 to 12. Examples of the aliphatic hydrocarbon group in which a hydrogen atom is substituted with an alicyclic hydrocarbon group include a 1-(adamantan-1-yl)alkane-1-yl group and the like.

Examples of the aliphatic hydrocarbon group in the above formula (X-0) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group. Group, octyl group, 2-ethylhexyl group and the like. The carbon number of the aliphatic hydrocarbon group of R ^{b4 to} R ^b6 is preferably 1 to 12. Examples of the aliphatic hydrocarbon group having a hydrogen atom substituted with an alicyclic hydrocarbon group include a 1-(adamantan-1-yl)alkane-1-yl group.

The alicyclic hydrocarbon group in the above formula (X-0) may be either monocyclic or polycyclic, and the hydrogen atom contained in the alicyclic hydrocarbon group is substituted with an alkyl group. Good. In this case, the carbon number of the alicyclic hydrocarbon group is 20 or less including the carbon number of the alkyl group. Examples of the monocyclic alicyclic hydrocarbon group include cyclopropyl groups, cyclobutyl groups, cyclopentyl groups, cyclohexyl groups, cycloheptyl groups, cyclooctyl groups, cyclodecyl groups and other cycloalkyl groups. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group and the like.

Examples of the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an alkyl group include a methylcyclohexyl group, a dimethylcyclohexyl group, a 2-alkyladamantan-2-yl group, a methylnorbornyl group and an isobornyl group. To be

Examples of the aromatic hydrocarbon group in the above formula (X-0) include a naphthyl group and a phenanthryl group.

Examples of the aromatic hydrocarbon group having a hydrogen atom substituted with an alkoxy group include 4-methoxynaphthyl group and 4-nbutoxynaphthyl group. Examples of the alkyl group in which a hydrogen atom is substituted with an aromatic hydrocarbon group, that is, an aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a trityl group, a naphthylmethyl group, a naphthylethyl group and the like. When the aromatic hydrocarbon group contains an alkyl group or an alicyclic hydrocarbon group, an alkyl group having 1 to 12 carbon atoms and an alicyclic hydrocarbon group having 3 to 18 carbon atoms are preferable.

Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxy group.

Examples of the acyl group include an acetyl group, a propionyl group and a butyryl group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an isopropylcarbonyloxy group, an n-butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group. , A pentyl carbonyloxy group, a hexyl carbonyloxy group, an octyl carbonyloxy group and a 2-ethylhexyl carbonyloxy group.

The ring containing a sulfur atom that may be formed by R ^b4 and R ^{b5 taken} together may be a monocyclic ring, a polycyclic ring, an aromatic ring, a non-aromatic ring, a saturated ring or an unsaturated ring. It may be present, and as long as it contains one or more sulfur atoms, it may further contain one or more sulfur atoms and/or one or more oxygen atoms. As the ring, a ring having 3 to 18 carbon atoms is preferable, and a ring having 4 to 18 carbon atoms is more preferable.

In the above formula (X-1), R ¹⁵ , R ¹⁶ and R ¹⁷ are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon group. number 6-12 aromatic hydrocarbon group, or an _OSO 2 -R ^D or _SO 2 -R ^E, or represent two or more are combined with each other configured ring of these groups. R ^D and R ^E 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. k, m, and n are each independently an integer of 0 to 5. When R ¹⁵ to R ¹⁷ and ^{R D} and ^{R E} are a plurality each of a plurality of ^R 15 ^{to R 17} and ^{R D} and ^{R E} may be the same as or different from each other.
In the above formula (X-2), R ¹⁸ and R ¹⁹ each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted 6 to 6 carbon atoms. 12 aromatic hydrocarbon group, or an _OSO 2 -R ^F or _SO 2 -R ^G, or represent two or more are combined with each other configured ring of these groups. R ^F and R ^G 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. i and j are each independently an integer of 0 to 5. When each of R ¹⁸ , R ¹⁹ , R ^F and R ^G is plural, the plural R ¹⁸ , R ¹⁹ , R ^F and R ^G may be the same or different.

Examples of the unsubstituted linear alkyl group represented by R ^{15 to} R ¹⁹ include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group.
Examples of the unsubstituted branched alkyl group represented by R ^{15 to} R ¹⁹ include i-propyl group, i-butyl group, sec-butyl group, t-butyl group and the like.
Examples of the unsubstituted aromatic hydrocarbon group represented by R ^{15 to} R ¹⁹ include aryl groups such as phenyl group and naphthyl group; aralkyl groups such as benzyl group and phenethyl group.

Examples of the substituent that may substitute the hydrogen atom of the alkyl group and the aromatic hydrocarbon group, for example, a fluorine atom, a chlorine atom, a bromine atom, a halogen atom such as iodine atom, a hydroxy group, a carboxy group, cyano 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.

As the ^R 15 ^{to R 19,} unsubstituted, straight or branched alkyl group, a fluorinated alkyl group, an unsubstituted monovalent aromatic hydrocarbon _{^{group, OSO 2 -R D, SO 2}} -R E Are preferred, a fluorinated alkyl group and an unsubstituted monovalent aromatic hydrocarbon group are more preferred, and a fluorinated alkyl group is even more preferred. R″ is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

As k, m and n in the above formula (X-1), an integer of 0 to 2 is preferable, 0 or 1 is more preferable, and 0 is further preferable.
As i and j in the above formula (X-2), an integer of 0 to 2 is preferable, 0 or 1 is more preferable, and 0 is further preferable.

Examples of the sulfonium cation include cations represented by the following formulas (b1-1) to (b1-10). Examples of the iodonium cation include cations represented by the following formulas (b2-1) to (b2-12).

Among these, the triphenylsulfonium cation represented by the above formula (b1-1) is preferable.

The onium cation is described in, for example, Advances in Polymer Science, Vol. 62, p. It can be produced according to the general method described in 1-48 (1984).

Examples of the [B] compound include the following formulas (1-1-1) to (1-1-17), formulas (1-2-1) to (1-2-3), and formulas (1-3-1). ) And the compound represented by (1-3-2) are preferable.

Formulas (1-1-1) to (1-1-17), Formulas (1-2-1) to (1-2-3) and Formulas (1-3-1) to (1-3-2). ), X ^<+> is synonymous with said Formula (1-1), (1-2), and (1-3).

<Synthesis of Compound [B]>
In the case of synthesizing a compound in which E ⁻ in the above formula (1-1) is SO ₃ ⁻ among the compounds [B], it has the following first step, the following second step, and the following third step. Can be synthesized by the synthetic method shown in the following reaction scheme.
A case where an organic halide represented by the following formula (ia) is reacted with a dithionite salt represented by D ₂ S ₂ O ₄ to obtain a sulfite salt represented by the following formula (ib) Step 1;
A second step of reacting a sulfite represented by the following formula (i-b) with an aqueous hydrogen peroxide solution to obtain a sulfonate represented by the following formula (i-c);
Third step of reacting a sulfonate represented by the following formula (ic) with an onium salt represented by XY

A, R< ^{1 >} , R ^{< 2 >} , k and X ^<+> are synonymous with said formula (1-1) in said formula (ia), (ib), (ic). Z is a halogen atom. D is an alkali metal. Y ⁻ is a monovalent anion.

In addition, in the above formula (1-1), when E ⁻ is COO ⁻ , or the compound represented by the above formula (1-2) can also be synthesized as the compound [B] by the same method as described above. it can.

As the content of the [B] compound, when the [B] compound is a [B1] compound that functions as an acid generator, 0.5 to 30 parts by mass relative to 100 parts by mass of the [A] polymer. Is preferred, 1 part by mass to 20 parts by mass is more preferred, 2.5 parts by mass to 15 parts by mass is further preferred, and 5 parts by mass to 10 parts by mass is particularly preferred.

On the other hand, when the [B] compound is a [B2] compound that functions as an acid diffusion controller, the content of the [B] compound is preferably 30 parts by mass or less based on 100 parts by mass of the [A] polymer. , 0.1 parts by mass to 20 parts by mass are more preferred, and 0.5 parts by mass to 10 parts by mass are even more preferred.

<[G] solvent>
The “[G] solvent” is a component for dissolving or dispersing the [A] polymer, compound and optional components. Examples of the [G] solvent include alcohol solvents, ketone solvents, amide solvents, ether solvents, ester solvents and the like. The solvent [G] may be used alone or in combination of two or more.

As the alcohol solvent, for example,
As a monoalcohol solvent, methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol, sec -Pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, furfuryl alcohol, phenol , Cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, diacetone alcohol and the like;
As the polyhydric alcohol solvent, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2 , 4-heptanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol and the like;
As a polyhydric alcohol partial ether solvent, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethyl Butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol Examples include monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether and the like.

Examples of the ketone solvent include, for example,
As a chain ketone solvent, acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, methyl-n-pentyl ketone, ethyl-n-butyl ketone, methyl-n- Hexyl ketone, di-iso-butyl ketone, trimethylnonanone, 2,4-pentanedione, acetonylacetone, diacetone alcohol, acetophenone, etc.;
Examples of the cyclic ketone solvent include cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, and methylcyclohexanone.

Examples of the amide solvent include:
As a chain amide solvent, N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropionamide and the like;
Examples of the cyclic amide-based solvent include N-methylpyrrolidone and N,N'-dimethylimidazolidinone.

As the ether solvent, for example,
As a chain ether solvent, diethyl ether, dipropyl ether, dibutyl ether, diphenyl ether, etc.;
Tetrahydrofuran, tetrahydropyran, etc. are mentioned as a cyclic ether type solvent.

Examples of the ester solvent include:
As an acetate solvent, methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-acetate Methoxybutyl, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate, glycol diacetate, methoxytriglycol acetate, etc.;
As an acetic acid ester solvent of a polyhydric alcohol partial ether, acetic acid ethylene glycol monomethyl ether, acetic acid ethylene glycol monoethyl ether, acetic acid diethylene glycol monomethyl ether, acetic acid diethylene glycol monoethyl ether, acetic acid diethylene glycol mono-n-butyl ether, acetic acid propylene glycol monomethyl ether, Propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, etc.;
Carbonic acid ester solvents such as dimethyl carbonate and diethyl carbonate;
Other carboxylic acid ester solvents include methyl acetoacetate, ethyl acetoacetate, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, lactic acid. Examples thereof include ethyl, n-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, and diethyl phthalate.

Among these, ketone solvents and ester solvents are preferable, as the ketone solvent, cyclic ketone solvents are more preferable, cyclohexanone is further preferable, and as the ester solvent, acetic acid ester of polyhydric alcohol partial ether is used. A system solvent is more preferable, and propylene glycol monomethyl ether acetate is further preferable.

<[C] acid generator>
The acid generator [C] is an acid generator other than the compound [B], and is a sulfonate compound that generates an acid upon irradiation with radiation. According to the acid generator [C], for example, when the structural unit containing an acid dissociable group of the polymer [A] is the structural unit (I-1), the acid generated from the acid generator is It serves as a catalyst and can dissociate the acid-dissociable group. As a result, the sensitivity of the radiation sensitive resin composition can be increased. The acid generator [C] may be used alone or in combination of two or more.

Examples of the acid generator [C] include onium salt compounds such as sulfonium salts, tetrahydrothiophenium salts, and iodonium salts.

Examples of the sulfonium salt include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, cyclohexyl 2-oxocyclohexylmethylsulfonium trifluoromethanesulfonate, dicyclohexyl 2 -Oxocyclohexylsulfonium trifluoromethanesulfonate, 2-oxocyclohexyldimethylsulfonium trifluoromethanesulfonate, 4-hydroxy-1-naphthyldimethylsulfonium trifluoromethanesulfonate, triphenylsulfonium 2-(adamantan-1-yl)-1,1-difluoroethane- 1-sulfonate, triphenylsulfonium 4-(adamantan-1-ylcarbonyloxy)-1,1,2,2-tetrafluorobutane-1-sulfonate and the like can be mentioned.

Examples of the tetrahydrothiophenium salt include 4-hydroxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-hydroxy-1-naphthyltetrahydrothiophenium nonafluoro-n-butanesulfonate, and 4-hydroxy-1. -Naphthyltetrahydrothiophenium perfluoro-n-octane sulfonate, 1-(1-naphthylacetomethyl)tetrahydrothiophenium trifluoromethanesulfonate, 1-(1-naphthylacetomethyl)tetrahydrothiophenium nonafluoro-n-butane Sulfonate, 1-(1-naphthylacetomethyl)tetrahydrothiophenium perfluoro-n-octanesulfonate, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophenium trifluoromethanesulfonate, 1-(3 5-dimethyl-4-hydroxyphenyl)tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophenium perfluoro-n-octanesulfonate, and the like. ..

Examples of the iodonium salt include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, bis(4-t-butylphenyl)iodonium trifluoromethanesulfonate, and bis( 4-t-butylphenyl)iodonium nonafluoro-n-butanesulfonate, bis(4-t-butylphenyl)iodonium perfluoro-n-octanesulfonate and the like can be mentioned.

Among these, onium salt compounds are preferable, sulfonium salts are more preferable, and triphenylsulfonium 2-(adamantan-1-ylcarbonyloxy)-1,1,2,2-tetrafluorobutane-1-sulfonate is further preferable. ..

From the viewpoint of the sensitivity and developability of the radiation-sensitive resin composition, the content of the [C] acid generator is 0.1 parts by mass to 30 parts by mass with respect to 100 parts by mass of the [A] polymer. It is preferably 1 part by mass to 20 parts by mass, more preferably 3 parts by mass to 10 parts by mass. When the content of the [C] acid generator is less than the above lower limit, the sensitivity and developability of the radiation-sensitive resin composition tend to decrease. If the content of the acid generator [C] exceeds the above upper limit, the transparency of the radiation-sensitive resin composition to radiation tends to decrease, and it tends to be difficult to obtain a rectangular resist pattern.

<[D] Acid diffusion controller>
The [D] acid diffusion controller has an effect of controlling the diffusion phenomenon of the acid generated from the [B] compound or the [C] acid generator in the resist film by exposure and suppressing an unfavorable chemical reaction in the unexposed portion. .. The acid diffusion controller contained in the radiation-sensitive resin composition may be in the form of a compound as described below (hereinafter, this embodiment is also referred to as "[D] acid diffusion controller"), or a part of the polymer. Or both of them.

Examples of the acid diffusion control agent [D] include amine compounds, amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like.

Examples of the amine compound include mono(cyclo)alkylamines; di(cyclo)alkylamines; tri(cyclo)alkylamines; substituted alkylaniline or a derivative thereof; ethylenediamine, N,N,N′,N′-tetra Methylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylamine, 2,2-bis(4 -Aminophenyl)propane, 2-(3-aminophenyl)-2-(4-aminophenyl)propane, 2-(4-aminophenyl)-2-(3-hydroxyphenyl)propane, 2-(4-amino) Phenyl)-2-(4-hydroxyphenyl)propane, 1,4-bis(1-(4-aminophenyl)-1-methylethyl)benzene, 1,3-bis(1-(4-aminophenyl)- 1-methylethyl)benzene, bis(2-dimethylaminoethyl)ether, bis(2-diethylaminoethyl)ether, 1-(2-hydroxyethyl)-2-imidazolidinone, 2-quinoxalinol, N,N , N′,N′-tetrakis(2-hydroxypropyl)ethylenediamine, N,N,N′,N″N″-pentamethyldiethylenetriamine, and the like.

Examples of the amide group-containing compound include Nt-butoxycarbonyl group-containing amino compound, formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, Examples thereof include benzamide, pyrrolidone, N-methylpyrrolidone, N-acetyl-1-adamantylamine and tris(2-hydroxyethyl) isocyanurate.

Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea and tri-n-butylthiourea. Are listed.

Examples of the nitrogen-containing heterocyclic compound include imidazoles; pyridines; piperazines; pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, piperidine ethanol, 3-piperidino-1,2-propanediol, morpholine, 4- Methylmorpholine, 1-(4-morpholinyl)ethanol, 4-acetylmorpholine, 3-(N-morpholino)-1,2-propanediol, 1,4-dimethylpiperazine, 1,4-diazabicyclo[2.2.2] ] Octane etc. are mentioned.

The acid diffusion controller [D] may be used alone or in combination of two or more kinds. The content of the [D] acid diffusion controlling agent is preferably less than 15 parts by mass with respect to 100 parts by mass of the [A] polymer. By setting the content of the acid diffusion controller [D] in the above range, the LWR performance and the like of the radiation-sensitive resin composition can be further improved.

<[E] Fluorine atom-containing polymer>
The [E] fluorine atom-containing polymer is a polymer containing a fluorine atom, and is a polymer different from the above [A] polymer. According to the radiation-sensitive resin composition, by further containing the [E] fluorine atom-containing polymer in addition to the [A] polymer, the [E] fluorine atom-containing polymer is formed on the surface layer of the resist film to be formed. Are unevenly distributed, and as a result, the hydrophobicity of the resist film surface can be improved. This makes it possible to suppress the elution of substances from the resist film when performing immersion exposure, and to make the receding contact angle between the resist film and the immersion liquid sufficiently high, enabling faster scanning. Become.

[E] The fluorine atom-containing polymer is not particularly limited, but is a polymer which is insoluble in the developer itself and becomes alkali-soluble by the action of an acid, and is itself soluble in the developer and alkali-soluble by the action of an acid. Include polymers that are insoluble in the developer and become alkali-soluble by the action of alkali, polymers that are themselves soluble in the developer and have increased alkali-solubility by the action of alkali, and the like. ..

Examples of the [E] fluorine atom-containing polymer include:
A structure in which a fluorinated alkyl group is bonded to the main chain;
A structure in which a fluorinated alkyl group is bonded to the side chain;
Examples include a structure in which a fluorinated alkyl group is bonded to the main chain and the side chain.

Examples of the monomer giving a structure in which a fluorinated alkyl group is bonded to the main chain include, for example, α-trifluoromethyl acrylate compound, β-trifluoromethyl acrylate compound, α,β-trifluoromethyl acrylate compound, and one or more kinds And a compound in which the hydrogen atom of the vinyl moiety is substituted with a fluorinated alkyl group such as a trifluoromethyl group.

Examples of the monomer giving a structure in which a fluorinated alkyl group is bonded to the side chain include, for example, those in which the side chain of an alicyclic olefin compound such as norbornene is a fluorinated alkyl group or a derivative thereof, acrylic acid or methacrylic acid. Examples thereof include ester compounds having a fluorinated alkyl group or a derivative thereof as a side chain, and those having a fluorinated alkyl group or a derivative thereof as a side chain (a site not containing a double bond) of one or more olefins.

Examples of monomers that give a structure in which a fluorinated alkyl group is bonded to the main chain and side chains include, for example, α-trifluoromethylacrylic acid, β-trifluoromethylacrylic acid, α,β-trifluoromethylacrylic acid. Ester compounds of which side chains are fluorinated alkyl groups or derivatives thereof, side chains of compounds in which one or more hydrogen atoms of vinyl moieties are substituted with fluorinated alkyl groups such as trifluoromethyl groups Substituted with its derivative, the hydrogen atom bonded to the double bond of one or more alicyclic olefin compounds is replaced with a fluorinated alkyl group such as trifluoromethyl group, and the side chain is a fluorinated alkyl group. And derivatives thereof. The alicyclic olefin compound means a compound in which a part of the ring is a double bond.

[E] The fluorine atom-containing polymer is a structural unit represented by the following formula (7) (hereinafter, also referred to as “structural unit (f1)”) and/or a structural unit represented by the following formula (8) (hereinafter, It is also preferable to have a “structural unit (f2).” The [E] fluorine atom-containing polymer has “another structural unit” other than the structural unit (f1) and the structural unit (f2). In addition, the [E] fluorine atom-containing polymer may contain one kind or two or more kinds of each structural unit.

[Structural unit (f1)]
The structural unit (f1) is a structural unit represented by the following formula (7).

In the above formula (7), R ^f3 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^f4 is a C 1-6 linear or branched alkyl group having a fluorine atom or a C 4-20 monovalent alicyclic hydrocarbon group having a fluorine atom. However, some or all of the hydrogen atoms contained in the above alkyl group and alicyclic hydrocarbon group may be substituted.

Examples of the linear or branched alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group and a butyl group.

Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms include cyclopentyl group, cyclopentylpropyl group, cyclohexyl group, cyclohexylmethyl group, cycloheptyl group, cyclooctyl group, cyclooctylmethyl group and the like. To be

Examples of the monomer that provides the structural unit (f1) include trifluoromethyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, perfluoroethyl (meth)acrylate, and perfluoro n-propyl. (Meth)acrylate, perfluoro i-propyl (meth)acrylate, perfluoro n-butyl (meth)acrylate, perfluoro i-butyl (meth)acrylate, perfluoro t-butyl (meth)acrylate, perfluorocyclohexyl (meth ) Acrylate, 2-(1,1,1,3,3,3-hexafluoro)propyl(meth)acrylate, 1-(2,2,3,3,4,5,5-octafluoro)pentyl (Meth)acrylate, 1-(2,2,3,3,4,4,5,5-octafluoro)hexyl (meth)acrylate, perfluorocyclohexylmethyl (meth)acrylate, 1-(2,2,3 ,3,3-Pentafluoro)propyl(meth)acrylate, 1-(2,2,3,3,4,4,4-heptafluoro)penta(meth)acrylate, 1-(3,3,4,4) , 5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluoro)decyl(meth)acrylate, 1-(5-trifluoromethyl-3,3,3) 4,4,5,6,6,6-octafluoro)hexyl (meth)acrylate and the like can be mentioned.

As the structural unit (f1), structural units represented by the following formulas (7-1) and (7-2) are preferable.

In the above formulas (7-1) and (7-2), R ^f3 has the same ^{meaning as} in the above formula (7).

Among these, the structural unit represented by formula (7-1) is more preferable.

The content ratio of the structural unit (f1) is preferably 10 mol% to 70 mol% and more preferably 20 mol% to 50 mol% with respect to all structural units constituting the [E] fluorine atom-containing polymer.

[Structural unit (f2)]
The structural unit (f2) is a structural unit represented by the following formula (8).

In the above formula (8), R ^f5 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^f6 is a (r+1)-valent linking group. X ¹ is a divalent linking group having a fluorine atom. R ^f7 is a hydrogen atom or a monovalent organic group. r is an integer of 1 to 3. However, when r is 2 or 3, a plurality of X ¹ and R ^f7 may be the same or different.

In the above formula (8), the (r+1)-valent linking group represented by R ^f6 is, for example, a linear or branched hydrocarbon group having 1 to 30 carbon atoms or an alicyclic ring having 3 to 30 carbon atoms. Formula hydrocarbon group, aromatic hydrocarbon group having 6 to 30 carbon atoms, or one or more groups selected from the group consisting of these groups and oxygen atom, sulfur atom, ether group, ester group, carbonyl group and imino group And a group in which and are combined. Further, the (r+1)-valent linking group may have a substituent.

Examples of the linear or branched hydrocarbon group having 1 to 30 carbon atoms include hydrocarbon groups such as methane, ethane, propane, butane, pentane, hexane, heptane, decane, icosane and triacontane (r+1). ) Groups excluding hydrogen atoms are included.

Examples of the alicyclic hydrocarbon group having 3 to 30 carbon atoms include, for example,
Examples of monocyclic saturated hydrocarbons include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, methylcyclohexane, ethylcyclohexane and the like;
As the monocyclic unsaturated hydrocarbon, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclodecene, cyclopentadiene, cyclohexadiene, cyclooctadiene, cyclodecadiene and the like;
As the polycyclic saturated hydrocarbon, bicyclo[2.2.1]heptane, bicyclo[2.2.2]octane, tricyclo[5.2.1.0 ^2,6 ]decane, tricyclo[3.3.1]. .1 ^3,7 ]decane, tetracyclo[6.2.1.1 ^3,6 . 0 ^2,7 ]dodecane, adamantane, etc.;
As the polycyclic unsaturated hydrocarbon, bicyclo[2.2.1]heptene, bicyclo[2.2.2]octene, tricyclo[5.2.1.0 ^2,6 ]decene, tricyclo[3.3. 1.1 ^3,7 ]decene, tetracyclo[6.2.1.1 ^3,6 . ^Examples include groups in which (r+1) hydrogen atoms have been removed from 0 ^2,7 ]dodecene and the like.

Examples of the aromatic hydrocarbon group having 6 to 30 carbon atoms include aromatic hydrocarbon groups such as benzene, naphthalene, phenanthrene, anthracene, tetracene, pentacene, pyrene, picene, toluene, xylene, ethylbenzene, mesitylene and cumene. Examples thereof include groups excluding (r+1) hydrogen atoms.

In the above formula (8), examples of the divalent linking group having a fluorine atom represented by X ¹ include a C 1-20 divalent straight chain hydrocarbon group having a fluorine atom. Examples of X ¹ include groups represented by the following formulas (X1-1) to (X1-6).

As X ¹ , the groups represented by the above formulas (X1-1) and (X1-2) are preferable, and the group represented by the formula (X1-2) is more preferable.

In the above formula (8), the monovalent organic group represented by R ^f7 is, for example, a linear or branched hydrocarbon group having 1 to 30 carbon atoms, or an alicyclic carbon group having 3 to 30 carbon atoms. A hydrogen group, an aromatic hydrocarbon group having 6 to 30 carbon atoms, or these groups and one or more groups selected from the group consisting of an oxygen atom, a sulfur atom, an ether group, an ester group, a carbonyl group and an imino group. Examples thereof include a combined group.

Examples of the structural unit (f2) include structural units represented by the following formulas (8-1) and (8-2).

In the above formula (8-1), R ^f6 is a divalent linear or branched saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, or a cyclic saturated or unsaturated carbon atom having 3 to 20 carbon atoms. Is a hydrocarbon group. R ^f5 , X ¹ and R ^f7 have the same ^{meaning as} in the above formula (8).

In the above formula (8-2), R ^f5 , X ¹ , R ^f7 and o have the same ^{meaning as} in the above formula (8). However, when k is 2 or 3, a plurality of X ¹ and R ^f7 may be the same or different.

Examples of the structural units represented by the above formulas (8-1) and (8-2) include, for example, the following formulas (8-1-1) to (8-1-3) and formula (8-2-1). ) And the like.

In the formulas (8-1-1) to (8-1-3) and the formula (8-2-1), R ^f5 has the same meaning as the formula (8).

As the structural unit (f2), the structural unit represented by the above formula (8-1) is preferable, and the structural unit represented by the above formula (8-1-3) is more preferable.

Examples of the monomer that provides the structural unit (f2) include (meth)acrylic acid [2-(1-ethyloxycarbonyl-1,1-difluoro-n-butyl)] ester and (meth)acrylic acid (1 , 1,1-Trifluoro-2-trifluoromethyl-2-hydroxy-3-propyl) ester, (meth)acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4) -Butyl) ester, (meth)acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-5-pentyl) ester, (meth)acrylic acid 2-{[5-(1' , 1′,1′-trifluoro-2′-trifluoromethyl-2′-hydroxy)propyl]bicyclo[2.2.1]heptyl} ester and the like. Among these, (meth)acrylic acid [2-(1-ethyloxycarbonyl-1,1-difluoro-n-butyl)] ester is preferable.

The content ratio of the structural unit (f2) is preferably 30 mol% to 90 mol% and more preferably 50 mol% to 80 mol% with respect to all structural units constituting the [E] fluorine atom-containing polymer.

[Other structural units]
[E] The fluorine atom-containing polymer may contain "another structural unit" other than the structural unit (f1) and the structural unit (f2). Examples of the other structural unit include the structural unit (I) of the polymer [A].

The content ratio of the other structural unit is preferably 5 mol% to 90 mol%, more preferably 10 mol% to 80 mol%, and more preferably 20 mol% to all structural units constituting the [E] fluorine atom-containing polymer. More preferred is mol% to 70 mol %.

The content of the [E] fluorine atom-containing polymer is preferably 20 parts by mass or less, more preferably 0.1 part by mass to 15 parts by mass, and more preferably 1 part by mass to 100 parts by mass of the [A] polymer. 10 parts by mass is more preferable, and 1 part by mass to 6 parts by mass is particularly preferable. When the content of the [E] fluorine atom-containing polymer exceeds the above upper limit, the water repellency of the resist film surface may become too high, resulting in poor development.

The fluorine atom content of the [E] fluorine atom-containing polymer is preferably higher than the fluorine atom content of the [A] polymer. When the fluorine atom content in the [E] fluorine atom-containing polymer is higher than that of the [A] polymer, it is formed by the radiation-sensitive resin composition containing the [A] polymer and the [E] fluorine atom-containing polymer. Further, the water repellency of the resist film surface can be further enhanced. The difference between the fluorine atom content of the [E] fluorine atom-containing polymer and the fluorine atom content of the [A] polymer is preferably 1% by mass or more, more preferably 3% by mass or more.
The fluorine atom content of the [E] fluorine atom-containing polymer is preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, and particularly preferably 10% by mass or more. The fluorine atom content rate (mass %) can be calculated from the structure of the polymer obtained by ¹³ C-NMR.

<[E] Method for synthesizing fluorine atom-containing polymer>
[E] The fluorine atom-containing polymer can be synthesized, for example, by polymerizing a monomer corresponding to each predetermined structural unit in a suitable polymerization solvent using a radical polymerization initiator.

Examples of the radical polymerization initiator include those similar to the radical polymerization initiator used in the method for synthesizing the [A] polymer. Examples of the polymerization solvent include the same as the polymerization solvent used in the method for synthesizing the [A] polymer.

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

The Mw of the [E] fluorine atom-containing polymer is preferably 1,000 to 50,000, more preferably 2,000 to 30,000, and even more preferably 3,000 to 10,000. When the Mw of the [E] fluorine atom-containing polymer is less than 1,000, a sufficient receding contact angle cannot be obtained. On the other hand, when Mw exceeds 50,000, the developability of the resist tends to decrease.

The ratio (Mw/Mn) of Mw and Mn of the [E] fluorine atom-containing polymer is preferably 1 to 5, and more preferably 1 to 3.

<[F] uneven distribution promoter>
The uneven distribution promoter (hereinafter, also referred to as “[F] uneven distribution promoter”) is a component that causes the [E] fluorine atom-containing polymer to more efficiently segregate on the resist film surface. When the radiation-sensitive resin composition contains the [F] uneven distribution promoter, the [E] fluorine atom-containing polymer can be effectively segregated on the resist film surface, and as a result, the [E] fluorine atom is contained. The amount of the polymer used can be reduced. Examples of the uneven distribution promoter [F] include a lactone compound, a carbonate compound, and a nitrile compound. The uneven distribution promoter [F] may be used alone or in combination of two or more.

Examples of the lactone compound include γ-butyrolactone, valerolactone, mevalonic lactone, norbornane lactone, and the like.

Examples of the carbonate compound include propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate and the like.

Examples of the nitrile compound include succinonitrile and the like.

Among these, lactone compounds are preferable, and γ-butyrolactone is more preferable.

As content of [F] uneven distribution promoter, 5 mass parts-300 mass parts are preferable with respect to 100 mass parts of [A] polymers, 10 mass parts-100 mass parts are more preferable, 20 mass parts-70 mass parts. Part by mass is more preferred.

<Other optional ingredients>
The radiation-sensitive resin composition contains, in addition to the components [A] to [G], other optional components such as a surfactant, an alicyclic skeleton-containing compound, and a sensitizer as long as the effects of the present invention are not impaired. Can be included. Two or more of the other optional components may be used in combination. The content of other optional components can be appropriately determined according to the purpose.

<Method for preparing radiation-sensitive resin composition>
The radiation-sensitive resin composition comprises a [A] polymer, a [B] compound, a [G] solvent and, if necessary, a [C] acid generator, a [D] acid diffusion controller, and an [E] fluorine atom-containing composition. It can be prepared by mixing each optional component such as a polymer in a predetermined ratio.

The solid content concentration of the radiation-sensitive resin composition is preferably 0.1% by mass to 50% by mass, more preferably 0.5% by mass to 30% by mass, and further preferably 1% by mass to 10% by mass.

<Method of forming resist pattern>
The method for forming the resist pattern is
Step of forming a resist film with the radiation-sensitive resin composition (hereinafter, also referred to as "resist film forming step"), step of exposing the resist film (hereinafter, also referred to as "exposure step"), and the exposed resist There is a step of developing the film (hereinafter, also referred to as “developing step”). Hereinafter, each step will be described.

[Resist film formation process]
In this step, a resist film is formed using the above radiation-sensitive resin composition of the present invention. The coating method is not particularly limited, but for example, suitable coating means such as spin coating, cast coating, and roll coating can be adopted. Examples of the substrate include a silicon wafer and a wafer coated with aluminum. Specifically, after applying the composition so that the obtained resist film has a predetermined thickness, prebaking (PB) is performed as necessary to volatilize the solvent in the coating film. The thickness of the coating film is preferably 10 nm to 500 nm. The temperature of PB is usually 60°C to 140°C, preferably 80°C to 120°C. The PB time is usually 5 seconds to 600 seconds, and preferably 10 seconds to 300 seconds.

[Exposure process]
In this step, the resist film formed in the resist film forming step is exposed. This exposure is performed by irradiating radiation through a liquid having an immersion medium such as water and a mask having a predetermined pattern in some cases. The radiation may be, for example, visible rays, ultraviolet rays, far ultraviolet rays, EUV (wavelength 13.5 nm), electromagnetic waves such as X-rays and γ-rays; electron rays, α-rays and the like, depending on the line width of the target pattern. It is appropriately selected from charged particle beams and the like. Among these, when the [A] polymer of the radiation-sensitive resin composition has a structural unit (I-1), far ultraviolet rays are preferable, and ArF excimer laser light (wavelength 193 nm) and KrF excimer laser light are used. (Wavelength 248 nm) is more preferable, and ArF excimer laser light is even more preferable. Further, when the polymer [A] of the radiation-sensitive resin composition has the structural unit (I-2) and the like, electron beam and EUV are preferable.

Further, it is preferable to perform post exposure bake (PEB) after the exposure. By performing PEB, the dissociation reaction of the acid dissociable group in the exposed portion of the resist film can be smoothly advanced. The temperature of PEB is usually 50°C to 180°C, preferably 80°C to 130°C. The PEB time is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds.

In the present invention, in order to maximize the potential of the radiation-sensitive resin composition, for example, an organic or inorganic antireflection film may be formed on the substrate used. Further, in order to prevent the influence of the basic impurities contained in the environmental atmosphere, for example, a protective film may be provided on the coating film. Further, in the case of performing the immersion exposure, in order to avoid direct contact between the immersion medium and the resist film, for example, an immersion protection film may be provided on the resist film.

[Development process]
In this step, the resist film exposed in the above exposure step is developed. Examples of the developer used for this development include an alkali developer and an organic solvent developer. As a result, a predetermined resist pattern is formed.

Examples of the alkaline developer include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, and the like. Methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, 1,5-diazabicyclo- Examples include alkaline aqueous solutions in which at least one alkaline compound such as [4.3.0]-5-nonene is dissolved.

As the organic solvent developer, for example,
As alcohol solvents, methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, etc.;
As ether solvents, diethyl ether, dipropyl ether, dibutyl ether, tetrahydrofuran, dioxane, diphenyl ether, anisole, etc.;
As a ketone solvent, acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl amyl kentone, methyl-n-butyl ketone, etc.;
As the amide solvent, N,N′-dimethylimidazolidinone, N-methylformamide, N,N-dimethylformamide and the like;
Examples of the ester solvent include diethyl carbonate, methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate and n-butyl acetate.

You may use these developing solutions individually or in combination of 2 or more types. After development, it is common to wash with water or the like and dry.

The radiation-sensitive acid generator of the present invention comprises a compound represented by the above formula (1-1), the above formula (1-2) or the above formula (1-3). Since the radiation-sensitive acid generator is composed of the compound having the above structure, it is preferably used as the radiation-sensitive acid generator.

<Compound>
The compound of the present invention is represented by the above formula (1-1), the above formula (1-2) or the above formula (1-3). Since the compound has the above structure, it can be suitably used as a compound constituting the radiation-sensitive acid generator.

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

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.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
The Mw and Mn of the polymer were measured by gel permeation chromatography (GPC) using a GPC column (G2000HXL: 2, G3000HXL: 1, G4000HXL: 1) manufactured by Tosoh Corporation under the following conditions. The dispersity (Mw/Mn) was calculated from the measurement results of Mw and Mn.
Elution solvent: Tetrahydrofuran Flow rate: 1.0 mL/min Sample concentration: 1.0 mass%
Sample injection volume: 100 μL
Column temperature: 40°C
Detector: Differential refractometer Standard substance: Monodisperse polystyrene

[ ¹³ C-NMR analysis]
Using a nuclear magnetic resonance apparatus (“JNM-ECX400” manufactured by JEOL Ltd.) and deuterated chloroform as a measurement solvent, the content ratio (mol %) of each structural unit in each polymer was determined.

<Synthesis of Compound [B]>
[Example 1] (Synthesis of compound (B-1))
To a 3 L eggplant type flask, 122 g (0.80 mol) of adamantanol A, 97.1 g (0.96 mol) of triethylamine and 800 g of acetonitrile were added, and the mixture was cooled to 0° C. in an ice bath. 120 g (0.88 mol) of acid chloride B was added dropwise thereto. After completion of dropping, the mixture was stirred at room temperature for 7 hours. After replacing the solvent with ethyl acetate, the salt was removed by filtration through Celite. After washing with water, the organic phase was dried over anhydrous sodium sulfate, and the solvent was distilled off. Purification by column chromatography gave 181 g of ethyl ester C (yield 90%).

15 g (59.5 mmol) of the ethyl ester C obtained above was added to a 200 mL eggplant-shaped flask and dissolved in 100 g of tetrahydrofuran. 34.2 g (71.3 mmol) of 5 mass% lithium hydroxide aqueous solution was dripped there. After stirring at room temperature for 10 hours, lithium hydroxide and an equivalent amount of concentrated hydrochloric acid were added, and the mixture was stirred at room temperature for 20 minutes. The organic phase was recovered and dried over anhydrous sodium sulfate, and then the solvent was distilled off to obtain 13.0 g of carboxylic acid D (yield 98%).

3.30 g (14.7 mmol) of the obtained carboxylic acid D was added to a 100 mL eggplant-shaped flask and dissolved in 15 g of acetonitrile. 5.07 g (44.1 mmol) of dichloromethyl methyl ether was slowly added dropwise thereto, and the mixture was heated with stirring at 60° C. for 10 hours. After removing the solvent and excess dichloromethyl methyl ether, 10 mL of acetonitrile was added, and the mixture was cooled to 0° C. in an ice bath (E). A solution prepared by dissolving 3.51 g (14.7 mmol) of 4-bromo-3,3,4,4-tetrafluorobutan-1-ol and 1.78 g (17.6 mmol) of triethylamine in 30 mL of acetonitrile. Was slowly added dropwise. After completion of dropping, the mixture was stirred at room temperature for 10 hours. After replacing the solvent with ethyl acetate, the salt was removed by filtration through Celite. After washing with water, the organic phase was dried over anhydrous sodium sulfate, and the solvent was distilled off. Purification by column chromatography gave 4.89 g of ester F (yield 75%).

In a 200 mL eggplant-shaped flask, 3.18 g (7.37 mmol) of ester F and 30 g of acetonitrile were added and dissolved. A solution prepared by dissolving 1.86 g (22.1 mmol) of sodium hydrogencarbonate and 2.57 g (14.7 mmol) of sodium dithionite sodium in 30 g of water was added thereto all at once, and then at 65° C. for 4 hours. Heated and stirred. After cooling to room temperature, it was washed twice with an aqueous sodium thiosulfate solution (G). The organic layer was collected, 2.51 g (22.1 mmol) of 30% hydrogen peroxide aqueous solution was added, and the mixture was heated with stirring at 55° C. for 6 hours. After cooling to room temperature, excess hydrogen peroxide was quenched with aqueous sodium sulfite solution (H). The organic layer was recovered, the solvent was distilled off, and then 2.20 g (7.37 mmol) of triphenylsulfonium chloride, 50 g of dichloromethane and 25 g of water were added, and the mixture was stirred at room temperature for 10 hours. After washing the organic layer 6 times with water, the solvent was distilled off to obtain 4.45 g of a compound represented by the following formula (B-1) (hereinafter, also referred to as “compound (B-1)”) (yield). Rate 87%). The scheme of synthesizing the (B-1) compound is shown below.

[Examples 2 to 16] (Synthesis of compound (B-2) to compound (B-22))
The compounds represented by the following formulas (B-2) to (B-22) were synthesized in the same manner as in Example 1 except that the precursor was appropriately selected.

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

[Synthesis Example 1] (Synthesis of Polymer (A-1))
7.97 g (35 mol%) of compound (M-6), 7.44 g (45 mol%) of compound (M-7) and 4.49 g (20 mol%) of compound (M-8) were added to 40 g of 2-butanone. After dissolution, 0.80 g of AIBN (5 mol% based on all monomers) was added as an initiator to prepare a monomer solution. Next, a 100 mL three-necked flask charged with 20 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80° C. with stirring, and the prepared monomer solution 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 solution was cooled with water and cooled to 30°C or lower. The cooled polymerization solution was put into 400 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was washed twice with 80 g of methanol, then filtered and dried at 50° C. for 17 hours to synthesize a white powdery polymer (A-1) (15.2 g, yield 76). %). The Mw of the polymer (A-1) was 7,300 and Mw/Mn was 1.53. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from (M-6), (M-7) and (M-8) was 34.3 mol%, 45.1 mol% and 20, respectively. It was 0.6 mol %.

[Synthesis Example 2] (Synthesis of Polymer (A-2))
6.88 g (40 mol%) of compound (M-1), 2.30 g (10 mol%) of compound (M-9) and 10.83 g (50 mol%) of compound (M-2) were added to 40 g of 2-butanone. After dissolving, 0.72 g of AIBN (5 mol% based on all the monomers) was added as an initiator to prepare a monomer solution. Next, a 100 mL three-necked flask containing 20 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80° C. with stirring, and the prepared monomer solution was added dropwise by 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 solution was cooled with water and cooled to 30°C or lower. The cooled polymerization solution was put into 400 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was washed twice with 80 g of methanol, then filtered and dried at 50° C. for 17 hours to synthesize a white powdery polymer (A-2) (14.9 g, yield 75). %). The Mw of the polymer (A-2) was 7,500, and the Mw/Mn was 1.55. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from (M-1), (M-9) and (M-2) was 40.1 mol%, 10.1 mol% and 9%, respectively. It was 0.8 mol %.

[Synthesis Example 3] (Synthesis of Polymer (A-3))
3.43 g (20 mol%) of compound (M-1), 3.59 g (15 mol%) of compound (M-11), 7.83 g (40 mol%) of compound (M-10) and compound (M-8). ) 5.16 g (25 mol%) was dissolved in 40 g of 2-butanone, and 0.72 g of AIBN (5 mol% based on all monomers) was added as an initiator to prepare a monomer solution. Next, a 100 mL three-necked flask containing 20 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80° C. with stirring, and the prepared monomer solution was added dropwise by 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 solution was cooled with water and cooled to 30°C or lower. The cooled polymerization solution was put into 400 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was washed twice with 80 g of methanol, then filtered and dried at 50° C. for 17 hours to synthesize a white powdery polymer (A-3) (15.3 g, yield 77). %). The Mw of the polymer (A-3) was 7,200 and Mw/Mn was 1.53. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from (M-1), (M-11), (M-10) and (M-8) was 19.5 mol% and 15 respectively. It was 0.5 mol%, 40.1 mol% and 24.9 mol%.

[Synthesis Example 4] (Synthesis of Polymer (A-4))
55.0 g (65 mol%) of compound (M-5) and 45.0 g (35 mol%) of compound (M-3), 4 g of AIBN as an initiator, and 1 g of t-dodecyl mercaptan were dissolved in 100 g of propylene glycol monomethyl ether. After that, the reaction temperature was kept at 70° C. in a nitrogen atmosphere and the copolymerization was carried out for 16 hours. After the completion of the polymerization reaction, the polymerization solution was dropped into 1,000 g of n-hexane to solidify and purify the polymer. Next, 150 g of propylene glycol monomethyl ether was added again to the above polymer, and then 150 g of methanol, 34 g of triethylamine and 6 g of water were further added, and the hydrolysis reaction was carried out for 8 hours while refluxing at the boiling point. After completion of the reaction, the solvent and triethylamine were distilled off under reduced pressure, the obtained polymer was dissolved in 150 g of acetone, and then added dropwise into 2,000 g of water to coagulate, and the produced white powder was filtered and filtered at 50° C. It was dried for an hour to obtain a white powdery polymer (A-4) (65.7 g, yield 77%). The Mw of the polymer (A-4) was 7,500 and Mw/Mn was 1.90. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from p-hydroxystyrene and (M-3) was 65.4 mol% and 34.6 mol %, respectively.

[Synthesis Example 5] (Synthesis of Polymer (E-1))
79.9 g (70 mol%) of compound (M-1) and 20.91 g (30 mol%) of compound (M-4) were dissolved in 100 g of 2-butanone, and dimethyl 2,2'-azo was used as an initiator. A monomer solution was prepared by dissolving 4.77 g of bisisobutyrate. 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 dropwise by 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 solution was cooled with water and cooled to 30°C or lower. After transferring the reaction solution to a 2 L separatory funnel, the above polymerization 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 to obtain a propylene glycol monomethyl ether acetate solution containing the polymer (E-1) as a solid content (yield 60%). The Mw of the polymer (E-1) was 7,200 and Mw/Mn was 2.00. As a result of ¹³ C-NMR analysis, the content rates of the respective structural units derived from (M-1) and (M-4) were 71.1 mol% and 28.9 mol%, respectively.

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

[[C] acid generator]
Compound represented by the following formula (C-1)

[[D] Acid diffusion control agent]
Compounds represented by the following formulas (D-1) and (D-2)

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

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

[Example 17] (Preparation of radiation-sensitive resin composition (J-1))
(A-1) 100 parts by mass as a polymer, (D-1) 2.3 parts by mass as a [D] acid diffusion controller, (B-1) 8.5 as a [B] compound. Parts by mass, (E-1) 3 parts by mass as [E] fluorine atom-containing polymer, (G-1) 2,240 parts by mass and (G-2) 960 parts by mass as [G] solvent, and [ F] Radiation-sensitive resin composition (J-1) was prepared by mixing 30 parts by mass of (F-1) as an uneven distribution promoter and filtering with a 0.2 μm membrane filter.

[Examples 18 to 48 and Comparative Examples 1 to 6]
Each radiation-sensitive resin composition (J-2) to (J- was operated in the same manner as in Example 17 except that the types and contents of [A] to [D] components shown in Table 1 below were used. 32) and (CJ-1) to (CJ-6) were prepared.

<Formation of resist pattern (1)>
A spin coater (“CLEAN TRACK ACT12” manufactured by Tokyo Electron Ltd.) was used to coat a composition for forming a lower antireflection film (“ARC66” manufactured by Brewer Science Co., Ltd.) on the surface of a 12-inch silicon wafer. By heating at 60° C. for 60 seconds, a lower antireflection film having a film thickness of 105 nm was formed. Each of the radiation-sensitive resin compositions prepared above was coated on the lower antireflection film using the above 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 optical conditions of NA=1.3 and dipole (Sigma 0.977/0.782) using an ArF excimer laser immersion exposure apparatus (“NSR-S610C” manufactured by NIKON Co., Ltd.). And exposed through a 40 nm line and space (1L1S) mask pattern. After the exposure, PEB was performed at 90° 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 exposure amount formed in a 1:1 line and space having a line width of 40 nm formed through a 1:1 line and space mask having a target size of 40 nm was taken as the optimum exposure amount.

<Formation of resist pattern (2)>
Negative resist pattern was obtained in the same manner as in the above resist pattern formation (1), except that n-butyl acetate was used instead of the above TMAH aqueous solution for organic solvent development, and washing with water was not performed. Formed.

<Evaluation>
The LWR performance, resolution, cross-sectional shape, depth of focus, exposure margin, CD uniformity, and MEEF of the resist pattern formed using each of the above radiation sensitive resin compositions were evaluated according to the following methods. The results are shown in Table 2. 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 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. The LWR performance (nm) shows that the smaller the value, the better. When the value of LWR performance is compared with the criterion, the value of LWR performance improvement of 10% or more (meaning that the value of LWR performance is 0.9 times or less) is “good” and less than 10%. Those having improved LWR performance of No. 2 were evaluated as “poor”.

[Resolution]
The size of the smallest resist pattern that can be resolved at the optimum exposure dose was defined as the resolution. The resolution (nm) indicates that the smaller the value, the better. At this time, when the resolution was compared with the determination standard, a resolution improvement of 10% or more (meaning that the resolution value becomes 0.9 times or less) was "good". ", and those having a resolution improvement of less than 10% were evaluated as "poor".

[Rectangularity of cross section]
The cross-sectional shape of the resist pattern resolved at the optimum exposure dose was observed, and the line width Lb in the middle of the resist pattern and the line width La in the upper part of the film were measured. At this time, the rectangularity of the cross-sectional shape was evaluated as “good” when it was within the range of 0.9≦La/Lb≦1.1, and “poor” when it was out of the above range.

[Depth of focus]
In the resist pattern resolved at the optimum exposure amount, the dimension when the focus is changed in the depth direction is observed, and the pattern dimension is 90% to 110% of the reference depth without any bridge or residue. The depth of focus was defined as the margin of focus. The larger the depth of focus (nm), the better. Regarding the depth of focus, when the depth of focus is improved by 10% or more (meaning that the value of the depth of focus is 1.1 times or more) when compared with the criterion, "good" is given and less than 10%. What was improved in depth of focus was evaluated as "poor".

[Exposure margin]
The above-mentioned optimum range of exposure dose when the pattern size resolved when a mask pattern for resist pattern formation of 40 nm line and space (1 L/1 S) is used is within ±10% of the design size of the mask. The ratio to the exposure amount was defined as the exposure allowance (EL performance) (%). The larger the exposure margin, the smaller the change amount of the patterning performance with respect to the change in the exposure amount, and the better. The exposure allowance was rated "good" when it was 18% or more, and "bad" when it was less than 18%.

[CD uniformity]
The formed resist pattern was observed from above the pattern using the scanning electron microscope. The line width was measured at 20 points in the range of 400 nm, the average value was measured at 500 points in total, and 3 sigma values were obtained from the distribution of the measured values, which was taken as CD uniformity (nm). The smaller the value of CD uniformity, the better the variation of the line width in the long cycle, and the better. The CD uniformity was evaluated as "good" when the CD uniformity was 1.5 nm or less, and evaluated as "poor" when the CD uniformity exceeded 1.5.

[MEEF]
Using the scanning electron microscope, at the optimum exposure dose, 5 types of mask sizes (38.0 nm Line/80 nm Pitch, 39.0 nm Line/80 nm Pitch,
The line width of the resist pattern resolved by 40.0 nm Line/80 nm Pitch, 41.0 nm Line/80 nm Pitch, 42.0 nm Line/80 nm Pitch) was measured. The obtained measured values were plotted with the horizontal axis as the mask size and the vertical axis as the line width formed with each mask size, and the slope of the approximate straight line calculated by the least squares method was obtained, and this slope was taken as the MEEF performance. The MEEF performance shows that the closer the value is to 1, the better. The MEEF performance was evaluated as "good" when it was 4.7 or less, and "poor" when it exceeded 4.7.

As can be seen from the results in Table 2, the radiation-sensitive resin composition of the present invention, when used for ArF exposure, exhibits LWR performance, resolution, cross-sectional shape, depth of focus, in both alkali development and organic solvent development. The exposure latitude, the CD uniformity, and the MEEF were good, whereas the comparative examples were inferior in each characteristic to the examples.

[Preparation of radiation-sensitive resin composition for electron beam exposure]
[Example 49]
(A-4) 100 parts by mass as a polymer, (D-1) 3.6 parts by mass as another acid diffusion controller [D], (B-1) 20 as a [B] compound. By mixing parts by mass, (G-1) 4,280 parts by mass and (G-2) 1,830 parts by mass as a [G] solvent, and filtering with a 0.2 μm membrane filter, radiation sensitivity is obtained. A resin composition (J-27) was prepared.

[Examples 50 to 73 and Comparative Examples 7 and 8]
Radiation-sensitive resin compositions (J-33) to (J-57) and (CJ-7) were operated in the same manner as in Example 49 except that the components shown in Table 3 below were used. And (CJ-8) were prepared.

<Formation of resist pattern (3)>
Using a spin coater (“CLEAN TRACK ACT8” by Tokyo Electron Ltd.) on the surface of an 8-inch silicon wafer, each radiation-sensitive resin composition shown in Table 3 is applied, and PB is performed at 90° C. for 60 seconds. It was Then, it cooled at 23 degreeC for 30 second(s), and formed the resist film with a film thickness of 50 nm. Next, this resist film was irradiated with an electron beam using a simple electron beam drawing apparatus (“HL800D” manufactured by Hitachi, Ltd., output: 50 KeV, current density: 5.0 A/cm ² ). After irradiation, PEB was performed at 120° C. for 60 seconds. Then, it was developed with a 2.38 mass% TMAH aqueous solution at 23° C. for 30 seconds, washed with water, and dried to form a positive resist pattern. The formed resist patterns were evaluated in the same manner as above. The evaluation results are shown in Table 4.

As can be seen from the results in Table 4, the radiation-sensitive resin composition of the present invention, when used in alkali development by electron beam exposure, has LWR performance, resolution, cross-sectional shape, depth of focus, exposure latitude and CD uniformity. The properties of the comparative example were poor, but the properties of the comparative example were poorer than those of the example.

According to the radiation-sensitive resin composition and the method for forming a resist pattern of the present invention, excellent MEEF performance, depth of focus and exposure latitude are exhibited, and excellent LWR performance, CD uniformity, resolution and cross-sectional shape are achieved. A resist pattern having a rectangular shape can be formed. Therefore, these can be suitably used for a processing process of a semiconductor device which is expected to be further miniaturized in the future.

Claims (12)

A polymer having a structural unit containing an acid dissociable group,
A radiation-sensitive resin composition containing a compound represented by the following formula (1-1) and a solvent.

(In the formula (1-1), A represents a monovalent organic group having 1 to 30 carbon atoms. E ⁻ represents SO ₃ ⁻ . X ⁺ represents a monovalent radiolytic onium cation. L is an oxygen atom, R ¹ is a single bond or a substituted or unsubstituted alkanediyl group having 1 to 10 carbon atoms, and R ² is a divalent organic group having 1 to 20 carbon atoms. K is an integer of 1 or more and 3 or less, and when k is 2 or more, a plurality of R ^1's may be the same or different, provided that k is 1 and R ¹ is a single bond. , A is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms, or -O-, -S-, -NH- at the carbon-carbon or bond side terminal of this hydrocarbon group. Or a group containing a heteroatom-containing group of -COO-, or when k is 1 or 2 and R ¹ is a substituted or unsubstituted alkanediyl group having 1 to 10 carbon atoms, two adjacent groups The carbonyl groups are each bonded to the same carbon atom in R ^{1. The} group which may substitute the monovalent hydrocarbon group is an alkyl group, an alkoxy group, an aryloxy group, an acyl group, an acyloxy group, A hydroxy group, a carboxy group, an amino group, a cyano group, a nitro group or a sulfonamide group. ) The radiation-sensitive resin composition according to claim 1, wherein R ² in the above formula (1-1) is represented by the following formula (2).

(In the formula (2), R ³ and R ⁴ are each independently a hydrogen atom or a monovalent organic group. Rf ¹ and Rf ² are each independently a fluorine atom or a fluorinated alkyl group. Yes, n is an integer of 1 or more and 6 or less, m is an integer of 0 or more and 6 or less.*1 indicates a site that binds to L.) The radiation-sensitive resin composition according to claim 1, wherein R ² in the above formula (1-1) is represented by the following formula (2′).

(In the formula (2′), R ^y is a substituted or unsubstituted alkanediyl group having 2 to 10 carbon atoms. Rf ¹ and Rf ² are each independently a fluorine atom or a fluorinated alkyl group. . N is an integer of 1 or more and 6 or less, m is an integer of 0 or more and 6 or less.*1 indicates a site that binds to L.) The radiation-sensitive resin composition according to claim 1, wherein k in the formula (1-1) is 1. The radiation-sensitive resin composition according to claim 1, wherein R ¹ in the formula (1-1) is a single bond, and four or more —C(O)— are not continuously bonded. The radiation-sensitive resin composition according to claim 1, wherein R ¹ in the formula (1-1) is a substituted or unsubstituted alkanediyl group, and the alkanediyl group is a methanediyl group. A in the above formula (1-1) is -OR or -R, R is a monovalent alicyclic hydrocarbon group having 3 to 30 ring members, and a monovalent aliphatic heterocycle having 3 to 30 ring members. The radiation-sensitive resin composition according to claim 1, which is a monovalent aromatic hydrocarbon group having 6 to 30 ring members or 6 to 30 ring members. The radiation-sensitive resin composition according to any one of claims 1 to 7, wherein the structural unit is represented by the following formula (3).

(In the formula (3), R ⁵ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Y ¹ is a monovalent acid dissociable group represented by the following formula (Y-1). is there.)

(In the formula (Y-1), R ^e1 is a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or an alicyclic hydrocarbon group having 3 to 20 carbon atoms. R ^e2 and R ^e3 are They are each independently a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or these groups are combined with each other and bonded to each other. Represents an alicyclic structure having 3 to 20 ring members which is formed together with a carbon atom.) The radiation-sensitive resin composition according to any one of claims 1 to 8, wherein the radiation-decomposable onium cation is a sulfonium cation or an iodonium cation. A step of forming a resist film,
The method comprises the steps of exposing the resist film, and developing the exposed resist film,
A method for forming a resist pattern, wherein the resist film is formed from the radiation-sensitive resin composition according to claim 1. A radiation-sensitive acid generator comprising a compound represented by the following formula (1-1).

(In the formula (1-1), A represents a monovalent organic group having 1 to 30 carbon atoms. E ⁻ represents SO ₃ ⁻ . X ⁺ represents a monovalent radiolytic onium cation. L is an oxygen atom, R ¹ is a single bond or a substituted or unsubstituted alkanediyl group having 1 to 10 carbon atoms, and R ² is a divalent organic group having 1 to 20 carbon atoms. K is an integer of 1 or more and 3 or less, and when k is 2 or more, a plurality of R ^1's may be the same or different, provided that k is 1 and R ¹ is a single bond. , A is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms, or -O-, -S-, -NH- at the carbon-carbon or bond side terminal of this hydrocarbon group. Or a group containing a heteroatom-containing group of -COO-, or when k is 1 or 2 and R ¹ is a substituted or unsubstituted alkanediyl group having 1 to 10 carbon atoms, two adjacent groups The carbonyl groups are each bonded to the same carbon atom in R ^{1. The} group which may substitute the monovalent hydrocarbon group is an alkyl group, an alkoxy group, an aryloxy group, an acyl group, an acyloxy group, A hydroxy group, a carboxy group, an amino group, a cyano group, a nitro group or a sulfonamide group. ) A compound represented by the following formula (1-1).

(In the formula (1-1), A represents a monovalent organic group having 1 to 30 carbon atoms. E ⁻ represents SO ₃ ⁻ . X ⁺ represents a monovalent radiolytic onium cation. L is an oxygen atom, R ¹ is a single bond or a substituted or unsubstituted alkanediyl group having 1 to 10 carbon atoms, and R ² is a divalent organic group having 1 to 20 carbon atoms. K is an integer of 1 or more and 3 or less, and when k is 2 or more, a plurality of R ^1's may be the same or different, provided that k is 1 and R ¹ is a single bond. , A is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms, or -O-, -S-, -NH- at the carbon-carbon or bond side terminal of this hydrocarbon group. Or a group containing a heteroatom-containing group of -COO-, or when k is 1 or 2 and R ¹ is a substituted or unsubstituted alkanediyl group having 1 to 10 carbon atoms, two adjacent groups The carbonyl groups are each bonded to the same carbon atom in R ^{1. The} group which may substitute the monovalent hydrocarbon group is an alkyl group, an alkoxy group, an aryloxy group, an acyl group, an acyloxy group, A hydroxy group, a carboxy group, an amino group, a cyano group, a nitro group or a sulfonamide group. )