JP2013029555A - Radiation-sensitive composition and pattern formation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation-sensitive composition satisfying basic characteristics such as sensitivity, having an excellent lithographic performance with LWR or the like defined as an index, and capable of forming a pattern having a favorable rectangular pattern shape without leaving residues on a pattern skirt part.SOLUTION: The radiation-sensitive composition includes: [A] a polymer component having a repeating unit (I) represented by the following formula (1); and [B] a radiation-sensitive acid-generating body. In the following formula (1), it is preferable that either of Rand R, and Rare mutually bonded to form a ring structure having a carbon number of 5 to 20.

Description

  The present invention relates to a radiation-sensitive composition and a pattern forming method.

  In the field of microfabrication for manufacturing integrated circuit elements and the like, lithography technology using short wavelength radiation represented by KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), etc. in order to obtain a higher degree of integration Development is underway. As a photoresist material corresponding to these radiations, from the viewpoint of high sensitivity, high resolution, etc., a chemical amplification type containing a component having an acid dissociable group and an acid generator that generates an acid upon irradiation with radiation. These radiation-sensitive compositions are widely used (see JP-A-59-45439).

  However, in recent years when further device miniaturization is progressing, the performance level required for the radiation-sensitive composition is further increased, and more excellent lithography properties and the like are required. Therefore, even if a conventional radiation-sensitive composition is used, the high level requirement cannot be met. For example, when a conventional radiation-sensitive composition is used, the lithographic properties using LWR (Line Width Roughness) as an index cannot be sufficiently satisfied. In addition, when a conventional radiation-sensitive composition is used, there is a disadvantage that a pattern having a good rectangular pattern shape cannot be obtained because a residue is generated at the bottom of the pattern.

  In view of such a situation, in order to form a finer resist pattern, the basic characteristics such as sensitivity are satisfied, the lithography characteristics using LWR and the like as an index are excellent, and a good rectangular shape without generating a residue at the pattern skirt portion. There is a need for a radiation sensitive composition capable of forming a pattern having a neutral pattern shape.

JP 59-45439 A

  The present invention has been made based on the circumstances as described above, and its purpose is to satisfy basic characteristics such as sensitivity, to be excellent in lithography characteristics using LWR as an index, and without generating a residue in the pattern skirt portion. The object is to provide a radiation-sensitive composition capable of forming a pattern having a good rectangular pattern shape.

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立して、水素原子、フッ素原子、メチル基又はトリフルオロメチル基である。Ｒ^３は、単結合又は炭素数１〜１０の鎖状炭化水素基である。Ｘは、１価の有機基である。Ｒ^４〜Ｒ^６は、それぞれ独立して、水素原子、炭素数１〜１０の鎖状炭化水素基又は炭素数６〜２０の芳香族炭化水素基である。但し、Ｒ^４〜Ｒ^６の少なくとも１つは、炭素数１〜１０の鎖状炭化水素基又は炭素数６〜２０の芳香族炭化水素基である。また、Ｒ^５及びＲ^６のいずれかとＲ^４とが互いに結合して炭素数５〜２０の環構造を形成してもよい。） The invention made to solve the above problems is
[A] A polymer component having a repeating unit (I) represented by the following formula (1) (hereinafter also referred to as “[A] polymer component”), and [B] a radiation-sensitive acid generator (hereinafter referred to as “A”). Also referred to as “[B] acid generator”)
Is a radiation-sensitive composition.

(In Formula (1), R ¹ and R ² are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ³ is a single bond or a chain having 1 to 10 carbon atoms. X is a monovalent organic group, R ^{4 to} R ⁶ are each independently a hydrogen atom, a chain hydrocarbon group having 1 to 10 carbon atoms, or a carbon group having 6 to 20 carbon atoms. It is an aromatic hydrocarbon group, provided that at least one of R ^{4 to} R ⁶ is a chain hydrocarbon group having 1 to 10 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms. Any of ⁵ and R ⁶ and R ⁴ may be bonded to each other to form a ring structure having 5 to 20 carbon atoms.

  The radiation sensitive composition of this invention contains the [A] polymer component which has a repeating unit (I) represented by the said Formula (1). The repeating unit (I) has a structure derived from a vinyl ether derivative and a structure derived from an aldehyde derivative. [A] The polymer component has the above-mentioned specific structure including an acetal structure, so that the polymer main chain and the side chain portion are decomposed by the action of an acid generated from the [B] acid generator upon exposure. As a result, the radiation-sensitive composition containing such a polymer component [A] satisfies basic characteristics such as sensitivity, is excellent in lithography characteristics using LWR or the like as an index, and further has a residue at the pattern bottom. It is possible to form a pattern having a good rectangular pattern shape without causing any problems. Furthermore, it is possible to form a desired pattern without requiring a developing operation using a developing solution, and it is possible to achieve a reduction in environmental burden by greatly reducing process waste solution.

Any of R ⁵ and R ⁶ and R ⁴ may be bonded to each other to form a ring structure having 5 to 20 carbon atoms. Since the structure derived from the aldehyde derivative constituting the repeating unit (I) has a ring structure such as an alicyclic group or an aromatic group, the pattern obtained using the radiation-sensitive composition has few residues and LWR and Excellent pattern shape.

  [A] It is preferable that the polymer component has repeating units (I) in which Xs are different from each other in the same or different polymers.

  [A] When the polymer component has repeating units (I) in which X is different from each other in the same or different polymers, the radiation-sensitive composition satisfies the sensitivity and has an LWR having a pattern obtained. And the pattern shape can be made more excellent. Furthermore, it has excellent etching resistance.

  The different Xs are preferably an electron-withdrawing group and an alicyclic group. Polymerization with an aldehyde derivative is promoted by the fact that X in the above formula (1) is an electron-withdrawing group, that is, the vinyl ether derivative that is one of the monomers giving the repeating unit (I) has an electron-withdrawing group. Thus, the content of the repeating unit (I) in the polymer can be improved. In addition, since the polymer component [A] further has a repeating unit (I) in which X is an alicyclic group, the radiation-sensitive composition satisfies the sensitivity and is sufficient for the obtained pattern. Etching resistance can be imparted.

（式（２）中、Ｒ^７〜Ｒ^１８は、それぞれ独立して、水素原子、重水素原子、ハロゲン原子又は炭素数１〜１５の炭化水素基である。Ａ^１〜Ａ^４は、それぞれ独立して、水素原子、重水素原子、ハロゲン原子、炭素数１〜１５の炭化水素基、又はホウ素原子、窒素原子、酸素原子、ケイ素原子、リン原子及び硫黄原子からなる群より選択される１種以上の原子を含む有機基である。ｍは、０〜２の整数である。但し、ｍが２の場合、複数のＲ^１３〜Ｒ^１８は、それぞれ同一でも異なっていてもよい。また、Ｒ^７〜Ｒ^１８及びＡ^１〜Ａ^４のいずれか複数の基が結合して脂環式構造を形成してもよい。＊は、上記式（１）におけるＲ^３との結合部位を示す。） The alicyclic group is preferably a group represented by the following formula (2).

(In the formula ^{(2), R} 7 ~R ¹⁸ are each independently a hydrogen atom, a deuterium atom, ^.A 1 to A ⁴ represents a hydrocarbon group having a halogen atom or 1 to 15 carbon atoms are each independently And one kind selected from the group consisting of a hydrogen atom, a deuterium atom, a halogen atom, a hydrocarbon group having 1 to 15 carbon atoms, or a boron atom, a nitrogen atom, an oxygen atom, a silicon atom, a phosphorus atom and a sulfur atom. It is an organic group containing the above atoms, m is an integer of 0 to 2. However, when m is 2, a plurality of R ^{13 to} R ¹⁸ may be the same or different. A plurality of groups ^{7 to} R ¹⁸ and A ^{1 to} A ⁴ may be bonded to form an alicyclic structure (* represents a bonding site with R ³ in the above formula (1).)

  When the alicyclic group has the specific structure, the radiation-sensitive composition can sufficiently satisfy the sensitivity, and can further improve the LWR and pattern shape of the obtained pattern.

  [A] The content of the polymer component is preferably 70% by mass or more of the total solid content. The radiation-sensitive composition contains [A] the polymer component in an amount of 70% by mass or more based on the total solid content, thereby sufficiently satisfying the sensitivity and imparting sufficient etching resistance to the resulting pattern.

The pattern forming method of the present invention comprises:
(1) A resist film forming step of forming a resist film on a substrate using the radiation sensitive composition of the present invention,
(2) an exposure step of exposing the resist film; and (3) a development step of developing the exposed resist film.

  According to the pattern formation method of the present invention, it is possible to form a pattern with little residue and excellent LWR and pattern shape.

  The developing step is preferably a step of heating the exposed resist film. According to the pattern forming method of the present invention, it is possible to form a desired pattern only by heating without requiring a developing operation using a developer, and the environmental load can be reduced by greatly reducing the process waste liquid. Can be achieved.

  The radiation-sensitive composition of the present invention satisfies basic characteristics such as sensitivity, is excellent in lithography characteristics using LWR as an index, and further has a pattern having a good rectangular pattern shape without generating a residue at the pattern skirt portion. Can be formed. In addition, when the radiation-sensitive composition of the present invention is used, it is possible to select a development process by heating without using a developer, so that environmental burden can be reduced.

<Radiation sensitive composition>
The radiation-sensitive composition contains a [A] polymer component and a [B] acid generator. Moreover, you may contain another component, unless the effect of this invention is impaired. Hereinafter, each component will be described in detail.

<[A] Polymer component>
[A] The polymer component has a repeating unit (I) represented by the above formula (1). The repeating unit (I) has a structure derived from a vinyl ether derivative and a structure derived from an aldehyde derivative. [A] The polymer component has the above-mentioned specific structure including an acetal structure, so that decomposition occurs in the polymer main chain and side chain by the action of an acid generated from the [B] acid generator upon exposure. That is, the repeating unit (I) has a structure in which two oxygen atoms are bonded to the carbon atom to which R ¹ in the above formula (1) is bonded. The bond is broken and becomes a carbonyl compound and an alcohol. As a result, in the exposed area, the [A] polymer component becomes a monomer-level low-molecular decomposition product, and the decomposition product can be evaporated and removed only by heating. The radiation-sensitive composition containing such a polymer component [A] satisfies basic characteristics such as sensitivity, is excellent in lithography characteristics using LWR as an index, and further does not generate a residue in the pattern skirt portion. A pattern having a good rectangular pattern shape can be formed. Furthermore, it is possible to form a desired pattern without requiring a developing operation using a developer. In addition, unless the effect of this invention is impaired, a [A] polymer component can have another repeating unit. Hereinafter, the repeating unit (I) and other repeating units will be described.

[Repeating unit (I)]
The repeating unit (I) is represented by the above formula (1). The formula (1), R ¹ and R ² are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ³ is a single bond or a chain hydrocarbon group having 1 to 10 carbon atoms. X is a monovalent organic group. R ^{4 to} R ⁶ are each independently a hydrogen atom, a chain hydrocarbon group having 1 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms. However, at least one of R ^{4 to} R ⁶ is a chain hydrocarbon group having 1 to 10 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms. Further, any of R ⁵ and R ⁶ and R ⁴ may be bonded to each other to form a ring structure having 5 to 20 carbon atoms.

  The repeating unit (I) is composed of a structure derived from a vinyl ether derivative and a structure derived from an aldehyde derivative as represented by the above formula (1). Each structure will be described in turn.

(Structure derived from vinyl ether derivatives)
The structure derived from the vinyl ether derivative of the repeating unit represented by the above formula (1) will be described.

The formula (1), the chain hydrocarbon group having 1 to 10 carbon atoms represented by R ^3, for example, methylene group, ethanediyl group, propanediyl, butanediyl group, pentanediyl group and the like. Of these, a methylene group, an ethanediyl group, and a propanediyl group are preferable.

  In the above formula (1), examples of the monovalent organic group represented by X include an electron-withdrawing group, an alicyclic group, an acid-dissociable group, a chain hydrocarbon group, and a heterocyclic group.

  Examples of the electron withdrawing group as the monovalent organic group represented by X include a halogen atom, a nitro group, a cyano group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alicyclic hydrocarbon group-substituted oxy Examples thereof include a carbonyl group, an aralkyloxycarbonyl group, an alkylsulfonyl group, a sulfonate group, and an oxoalkyl group.

As said acyl group, C1-C10 aliphatic acyl groups, such as a formyl group, an acetyl group, a propionyl group, an alicyclic acyl group, an aromatic acyl group etc. are mentioned, for example.
Examples of the alkoxycarbonyl group include C2-C10 alkoxycarbonyl groups such as a methoxycarbonyl group and an ethoxycarbonyl group.
Examples of the aryloxycarbonyl group include aryloxycarbonyl groups having 7 to 11 carbon atoms such as a phenyloxycarbonyl group.
As said alicyclic hydrocarbon group substituted oxycarbonyl group, C5-C15 alicyclic hydrocarbon substituted oxycarbonyl groups, such as a cyclohexyloxycarbonyl group, etc. are mentioned, for example.
Examples of the aralkyloxycarbonyl group include an aralkyloxycarbonyl group having 8 to 12 carbon atoms such as a benzyloxycarbonyl group.
As said alkylsulfonyl group, a C1-C10 alkylsulfonyl group etc. are mentioned, for example, Among these, a C1-C6 alkylsulfonyl group is preferable.
As said sulfonate group, a C1-C10 sulfonate group etc. are mentioned, for example, Among these, a C1-C6 sulfonate group is preferable.
Examples of the oxoalkyl group include an oxoethyl group, an oxobutyl group, and an oxohexyl group.

  Of these, halogen atoms such as chlorine atoms are preferred as the electron-withdrawing group.

  The alicyclic group as the monovalent organic group represented by X may be a monocyclic alicyclic group or a polycyclic alicyclic group. Of these, the group represented by the above formula (2) is preferable.

In said formula (2), R < ⁷ > -R < ¹⁸ > is respectively independently a hydrogen atom, a deuterium atom, a halogen atom, or a C1-C15 hydrocarbon group. A ^{1 to} A ⁴ are each independently a hydrogen atom, a deuterium atom, a halogen atom, a hydrocarbon group having 1 to 15 carbon atoms, or a boron atom, a nitrogen atom, an oxygen atom, a silicon atom, a phosphorus atom, and a sulfur atom. An organic group containing one or more atoms selected from the group consisting of: m is an integer of 0-2. However, when m is 2, the plurality of R ^{13 to} R ¹⁸ may be the same or different. In addition, a plurality of groups of R ^{7 to} R ¹⁸ and A ^{1 to} A ⁴ may be bonded to form an alicyclic structure. * Indicates a binding site with R ³ in the above formula (1).

Examples of the hydrocarbon group having 1 to 15 carbon atoms represented by R ^{7 to} R ¹⁸ include a linear or branched hydrocarbon group having 1 to 15 carbon atoms and an alicyclic group having 3 to 15 carbon atoms. And an aromatic hydrocarbon group having 6 to 15 carbon atoms. Note that some or all of the hydrogen atoms of the hydrocarbon group may be substituted.

  Examples of the linear or branched hydrocarbon group having 1 to 15 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, and n-pentyl. Group, i-pentyl group, n-hexyl group, i-hexyl group and the like.

  Examples of the alicyclic group having 3 to 15 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

  As said C6-C15 aromatic hydrocarbon group, a phenyl group, a naphthyl group, etc. are mentioned, for example.

  Examples of the organic group containing one or more atoms selected from the group consisting of boron atom, nitrogen atom, oxygen atom, silicon atom, phosphorus atom and sulfur atom include lactone ring, cyclic carbonate, sultone ring, furan ring, And groups containing a thiophene ring, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, a dibenzothiophene ring, a pyridine ring, and the like.

Examples of the alicyclic structure that may be formed by combining any ^{one of} R ^{7 to} R ¹⁸ and A ^{1 to} A ⁴ include a monocyclic alicyclic group and a polycyclic alicyclic group. Etc. Of these, alicyclic groups that are 3- to 8-membered rings are preferred.

  Examples of the alicyclic group represented by the above formula (2) include groups represented by the following formulas (2-1) to (2-6).

  Of these, a group represented by the above formula (2-1) is preferable.

  The acid dissociable group as the monovalent organic group represented by X is not particularly limited as long as it includes a group that can be dissociated by the action of the acid generated by the [B] acid generator. The group etc. which are represented by these are mentioned.

（式（３）中、Ｒ^１９〜Ｒ^２１は、それぞれ独立して、炭素数１〜４のアルキル基又は炭素数４〜２０の脂環式基である。但し、Ｒ^１９及びＲ^２０は互いに結合して、それらが結合している炭素原子と共に２価の脂環式基を形成していてもよい。また、上記アルキル基及び脂環式基が有する水素原子の一部又は全部は置換されていてもよい。）

(In Formula (3), R ^{19 to} R ²¹ are each independently an alkyl group having 1 to 4 carbon atoms or an alicyclic group having 4 to 20 carbon atoms, provided that R ¹⁹ and R ²⁰ are each other. It may be bonded to form a divalent alicyclic group together with the carbon atom to which they are bonded, and some or all of the hydrogen atoms of the alkyl group and alicyclic group may be substituted. May be.)

  Of the acid dissociable groups represented by the above formula, groups represented by the following formulas (3-1) to (3-8) are preferred.

  Examples of the chain hydrocarbon group as the monovalent organic group represented by X include, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, n- A pentyl group, i-pentyl group, n-hexyl group, i-hexyl group and the like can be mentioned. Of these, i-butyl groups are preferred.

  Examples of the heterocyclic group as the monovalent organic group represented by X include a lactone group, a sultone group, and a cyclic carbonate group. Of these, a lactone group is preferable, and a δ valerolactone group is more preferable.

  In the above formula (1), the monovalent organic group represented by X is preferably an electron-withdrawing group, an alicyclic group, an acid-dissociable group, or a chain hydrocarbon group.

  [A] It is preferable that the polymer component has repeating units (I) in which Xs are different from each other in the same or different polymers. [A] When the polymer component has repeating units (I) in which X is different from each other in the same or different polymers, the radiation-sensitive composition satisfies the sensitivity and has an LWR having a pattern obtained. In addition, controllability of resist characteristics such as etching resistance can be improved. In addition, the X different from each other is preferably a plurality of groups selected from the group consisting of an electron withdrawing group, an alicyclic group, an acid dissociable group, a chain hydrocarbon group, and a heterocyclic group. Of these, a combination of an electron withdrawing group and an alicyclic group, a combination of an electron withdrawing group and a heterocyclic group, and a combination of an acid dissociable group and a chain hydrocarbon group are more preferred. A combination with a cyclic group is more preferred.

(Structure derived from aldehyde derivatives)
The structure derived from the aldehyde derivative of the repeating unit represented by the above formula (1) will be described.

In said formula (1), as a C1-C10 chain hydrocarbon group represented by R < ⁴ > -R < ⁶ >, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group etc., for example Is mentioned.

The formula ^(1), the aromatic hydrocarbon group having 6 to 20 carbon atoms represented by R 4 to R ^6, a phenyl group, a naphthyl group and the like.

Examples of the ring structure having 5 to 20 carbon atoms that may be formed by any one of R ⁵ and R ⁶ and R ⁴ bonded to each other are represented by the following formulas (4-1) to (4-10). Groups and the like.

  In the above formulas (4-1) to (4-10), * represents a site bonded to the polymer main chain in the above formula (1).

The structure derived from the aldehyde derivative is preferably a structure in which any of R ⁵ and R ⁶ in the above formula (1) and R ⁴ are bonded to each other to form a ring structure, and the above ring structure is represented by the above formula (4- 5), more preferably a group represented by (4-8), and further preferably a group represented by the above formula (4-8).

  The repeating unit (I) can be obtained by copolymerizing a vinyl ether derivative and an aldehyde derivative according to the synthesis method described later.

Examples of the vinyl ether derivative include 2-chloroethyl vinyl ether, 2-bromoethyl vinyl ether, 3-chloropropyl vinyl ether, 3-bromopropyl vinyl ether, 2-cyanoethyl vinyl ether, (2-methoxycarbonylethyl) vinyl ether, (2-ethoxycarbonylethyl). Vinyl ethers having an electron-withdrawing group such as vinyl ether, (2-phenoxycarbonylethyl) vinyl ether, (2-benzyloxycarbonylethyl) vinyl ether, (3-oxobutyl) vinyl ether;
Vinyl ethers having an alicyclic group represented by the following formulas (1-1) to (1-20);
Vinyl ethers having an acid dissociable group represented by the following formulas (1-21) to (1-26);
Chain hydrocarbon groups such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, sec-butyl vinyl ether, tert-butyl vinyl ether, i-butyl vinyl ether, methyl propenyl ether, ethyl propenyl ether Vinyl ethers having:
and vinyl ethers having a heterocyclic group such as γ-butyrolactone and δ-valerolactone.

  Of these, 2-chloroethyl vinyl ether having an electron-withdrawing group, vinyl ether represented by the above formula (1-1) having an alicyclic group, and the above formula (1-22) having an acid dissociable group. Vinyl ethers are preferred.

Examples of aldehyde derivatives include benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, 2-ethylbenzaldehyde, 3-ethylbenzaldehyde, 4-ethylbenzaldehyde, 2-isopropylbenzaldehyde, 3-isopropylbenzaldehyde, 4- Isopropylbenzaldehyde, 2-t-butylbenzaldehyde, 3-t-butylbenzaldehyde, 4-t-butylbenzaldehyde, 2,3-dimethylbenzaldehyde, 2,4-dimethylbenzaldehyde, 2,5-dimethylbenzaldehyde, 2,6-dimethyl Benzaldehyde, 2-naphthaldehydride, mesitaldehydride, 3-phenylbenzaldehyde, 9-anthracenecarbaldehyde, 9-methyl-10 -Aromatics such as anthraldehyde, isophthalaldehyde, terephthalaldehyde, 2,2'-biphenylcarboxaldehyde, p-hydroxybenzaldehyde, 5-formylindane, p-chlorobenzaldehyde, m-methoxybenzaldehyde, 4-phenoxybenzaldehyde, cinnamaldehyde Aldehydes;
Perylaldehyde, 3-formylindole-5-carboxylic acid methyl ester, 3-chromone carbaldehyde, β-cyclocitral, myrtenal, 5-methoxy-2H-chromene-3-carbaldehyde, 6-methoxychromene-3-carbaldehyde And alicyclic aldehydes such as 6,8-dimethyl-4-oxo-4H-1-benzopyran-3-carboxaldehyde, and ophioborin A.

  Of these, benzaldehyde, cinnamaldehyde, β-cyclocitral, myrtenal, and perylaldehyde are preferable from the viewpoints of copolymerization with vinyl ether derivatives and the harmfulness of acid decomposition products.

  Examples of the repeating unit (I) include repeating units represented by the following formulas (I-1) to (I-14).

In the above formulas (I-1) to (I-14), R ¹ and R ² have the same meaning as in the above formula (1).

  Among these, the repeating units represented by the above formulas (I-1) to (I-8) and (I-14) are preferable, and the above formulas (I-1) to (I-3) and (I-8) are preferable. And repeating units represented by (I-14) are more preferred.

  [A] In the polymer component, it is preferable that there are many portions where the repeating units (I) are continuously arranged. That is, it is preferable that the [A] polymer component has many portions where the vinyl ether derivative and the aldehyde derivative are alternately copolymerized. When there are many parts where the repeating units (I) are continuously arranged, [B] degradation of the polymer main chain and side chain part caused by the action of the acid generated from the acid generator results in a low molecular level monomer. This is because the region where the decomposition proceeds is increased.

  [A] In the polymer component, the content of the repeating unit (I) is preferably 70 mol% or more and 100 mol% or less, more preferably 80 mol% or more and 100 mol% or less, and 90 mol% or more and 100 mol% or less. Further preferred. By setting the content of the repeating unit (I) in the above range, [B] decomposition of the polymer side chain portion and the polymer main chain portion caused by the action of the acid generated from the acid generator occurs at a high frequency. The radiation composition is excellent in lithography characteristics using LWR or the like as an index, and can form a pattern having a good rectangular pattern shape without generating a residue at the pattern bottom. In addition, the [A] polymer component may have 1 type, or 2 or more types of repeating unit (I).

[Other repeat units]
The repeating unit that can be used in combination with the repeating unit (I) is not particularly limited as long as it is a repeating unit derived from a cationically polymerizable monomer component. Examples of the monomer component capable of cationic polymerization include aliphatic olefins, aromatic vinyls, dienes, silanes, δ-valerolactone, ε-caprolactone, vinylcarbazole, β-pinene, acenaphthylene, and the like. Examples include the body. These monomers can be used alone or in combination of two or more.

  Examples of the aliphatic olefin monomers include ethylene, propylene, 1-butene, 2-methyl-1-butene, 3-methyl-1-butene, pentene, hexene, cyclohexene, 4-methyl-1-pentene, Vinylcyclohexene, octene, norbornene and the like can be mentioned.

  Examples of the aromatic vinyl monomer include styrene, o-, m- or p-methylstyrene, α-methylstyrene, β-methylstyrene, 2,6-dimethylstyrene, 2,4-dimethylstyrene, α -Methyl-o-methylstyrene, α-methyl-m-methylstyrene, α-methyl-p-methylstyrene, β-methyl-o-methylstyrene, β-methyl-m-methylstyrene, β-methyl-p- Methylstyrene, 2,4,6-trimethylstyrene, α-methyl-2,6-dimethylstyrene, α-methyl-2,4-dimethylstyrene, β-methyl-2,6-dimethylstyrene, β-methyl-2 , 4-dimethylstyrene, o-, m- or p-chlorostyrene, 2,6-dichlorostyrene, 2,4-dichlorostyrene, α-chloro-o-chlorostyrene, α-c Rollo-m-chlorostyrene, α-chloro-p-chlorostyrene, β-chloro-o-chlorostyrene, β-chloro-m-chlorostyrene, β-chloro-p-chlorostyrene, 2,4,6-trichloro Styrene, α-chloro-2,6-dichlorostyrene, α-chloro-2,4-dichlorostyrene, β-chloro-2,6-dichlorostyrene, β-chloro-2,4-dichlorostyrene, o-, m -Or p-t-butylstyrene, o-, m- or p-methoxystyrene, o-, m- or p-chloromethylstyrene, o-, m- or p-bromomethylstyrene, substituted with a silyl group Examples thereof include styrene derivatives, indene, vinyl naphthalene and the like.

  Examples of the diene monomer include butadiene, isoprene, cyclopentadiene, cyclohexadiene, dicyclopentadiene, divinylbenzene, and ethylidene norbornene.

  Examples of the silane compound include vinyltrichlorosilane, vinylmethyldichlorosilane, vinyldimethylchlorosilane, vinyldimethylmethoxysilane, vinyltrimethylsilane, divinyldichlorosilane, divinyldimethoxysilane, divinyldimethylsilane, 1,3-divinyl-1,1, Examples include 3,3-tetramethyldisiloxane, trivinylmethylsilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-methacryloyloxypropylmethyldimethoxysilane.

<[A] Polymer component synthesis method>
[A] The polymer component can be synthesized by a known living cationic polymerization method. The catalyst system used in the above polymerization method is not particularly limited as long as it allows cationic polymerization to proceed in a living manner. For example, a system using HI as a polymerization initiator and I ₂ as a Lewis acid (Japanese Patent Laid-Open No. 60). -228509));
A system using a protonic acid as a polymerization initiator, an organoaluminum compound as a Lewis acid, and an ether compound as a Lewis base, a protonic acid as a polymerization initiator, an organoaluminum compound as a Lewis acid, and an ester compound as a Lewis base Catalyst systems in which a protonic acid and an additive are combined (eg, Japanese Patent No. 3096494, Japanese Patent Publication No. 7-2805, Japanese Patent Laid-Open No. 62-257910, Japanese Patent Laid-Open No. 1-108202 and JP-A-1-108203) and the like.

  Among these catalyst systems, proton acids as polymerization initiators, organoaluminum compounds as Lewis acids, and ether compounds as Lewis bases are used because the cost can be reduced especially for industrial equipment corrosion countermeasures. A catalyst system combining a protonic acid and an additive such as a system, a system using a proton acid as a polymerization initiator, an organoaluminum compound as a Lewis acid, and an ester compound as a Lewis base is preferable.

  Specific examples of the Lewis base, Lewis acid and polymerization initiator used in the catalyst system are shown below.

<Lewis base>
[A] Examples of Lewis bases that can be used for living cationic polymerization in the synthesis of polymer components include pyridine compounds, amine compounds other than pyridine compounds, ester compounds, ether compounds, thioether compounds, and phosphine compounds. Examples thereof include compounds, sulfoxide compounds, and metal compounds having an oxygen atom bonded to a metal atom. Of these, ester compounds and ether compounds that are weak Lewis bases are preferred.

  Examples of the pyridine compound include 2-methylpyridine, 3-methylpyridine, 3,5-dimethylpyridine, 2,6-dimethylpyridine, 2,6-di-t-butylpyridine, 2-methylpyrazine and the like. It is done.

  Examples of amine compounds other than the above pyridine compounds include triethylamine, triphenylamine, 1-methylpyrrolidine, 1-methylpiperidine, 1,4-diazabicyclo [2.2.2] octane, N, N, N ′, N′-tetraacetylethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, N, N-dimethylacetamide and the like can be mentioned.

Examples of the ester compound include aliphatic monocarboxylic acid esters such as methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, phenyl acetate, methyl propionate, and ethyl propionate;
Aromatic monocarboxylic acid esters such as methyl benzoate, ethyl benzoate, ethyl-p-anisate;
Halogenated aliphatic monocarboxylic acid esters such as methyl chloroformate, ethyl chloroformate, methyl chloroacetate, ethyl chloroacetate, ethyl dichloroacetate, ethyl trichloroacetate, ethyl trifluoroacetate;
Dialkyl phthalates such as dimethyl phthalate;
Dialkyl maleates such as diethyl maleate;
Examples include isovaleric anhydride and acetoacetic acid-n-amyl. Of these, aliphatic monocarboxylic acid esters and halogenated aliphatic monocarboxylic acid esters are preferred.

Examples of the ether compounds include chain ethers such as diethyl ether, dipropyl ether, dibutyl ether, diphenyl ether, dibenzyl ether, 1,2-dimethoxyethane, 4-methoxy-4-methyl-3-pentanone;
Examples include cyclic ethers such as tetrahydrofuran, 1,4-dioxane, and 1,3-dioxolane. Of these, cyclic ethers are preferred.

  Examples of the thioether compound include tetrahydrothiophene and tetrahydrothiophene-1,1-dioxide.

  Examples of the phosphine compound include trialkylphosphine and trialkylphosphine oxide.

  The amount of Lewis base used varies depending on the types of aldehydes and vinyl ether compounds used as reaction raw materials, but is usually 0.001 mol to 100 mol and 0.1 mol to 25 mol with respect to 1 mol of aldehydes. Mole is preferable, and 1 mol to 5 mol is more preferable. If the amount added is too large, the polymerization rate is slow, and it takes a long time to obtain the desired polymer, which is not preferable. Moreover, when there are too few addition amounts, the effect cannot be exhibited but a polymerization behavior and a terminal functionalization rate may become uncontrollable.

<Lewis acid>
[A] Examples of Lewis acids that can be used for living cationic polymerization in the synthesis of the polymer component include Group 4 elements of the periodic table such as titanium, zirconium, and hafnium, Group 8 elements such as iron, and Group 12 elements such as zinc. Group 13 elements such as group 13 elements such as aluminum, gallium and indium, group 14 elements such as silicon, germanium and tin, group 15 elements such as bismuth, and solid acids exhibiting Lewis acidity.

Examples of the halide include FeCl ₃ , SnCl ₄ , GaCl ₃ , TiCl ₄ , TiBr ₄ , BCl ₃ , BF ₃ , SnCl ₄ , SbCl ₅ , SbF ₅ , WCl ₆ , TaCl ₅ , VCl ₅ , FeCl ₃ , and FeCl ₃ . ₂ , metal halides such as AlCl ₃ and AlBr ₃ , and organometallic halides such as Et ₂ AlCl and EtAlCl ₂ .

  Examples of the solid acid include metal oxides such as silica, alumina, titanium oxide, iron oxide, cobalt oxide, and indium oxide, heteropoly acids, and supported metal halides.

  Among these, as the Lewis acid, from the viewpoint of excellent polymerization controllability, iron, tin and gallium halides are preferable, and iron, tin and gallium chlorides are more preferable.

  The amount of the Lewis acid used can be set in view of the polymerization characteristics and polymerization concentration of the monomer used. When the polymerization initiator such as a protonic acid is not used, the amount of Lewis acid used is usually 0.1 to 100 mol, preferably 1 to 60 mol, per 1 mol of the monomer. In the case of using a polymerization initiator such as a protonic acid, the amount of Mr. Lewis used is usually 0.0001 to 0.1 mol, preferably 0.0005 to 0.05 mol, relative to 1 mol of aldehydes, 0.001-0.02 mol is more preferable.

<Polymerization initiator>
[A] Examples of the polymerization initiator that can be used for the living cationic polymerization in the synthesis of the polymer component include a proton acid, a compound serving as a cation source, and the like.

  Examples of the protonic acid include mineral acids such as hydrogen chloride; carboxylic acids such as acetic acid and trifluoroacetic acid; methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, and naphthalenesulfonic acid. And the like, and the like. Of these, sulfonic acids such as ethanesulfonic acid are preferable in terms of the by-product suppression effect of the cyclic trimer and the stabilization effect of the growth species.

  Examples of the cation source compound include trimethylsilyl halide, a compound in which hydrogen halide is added to a double bond of vinyl ether, and the like. Of these, compounds in which hydrogen chloride is added to the double bond of trimethylsilyl iodide and vinyl ether are preferable.

  The usage-amount of a protonic acid is 0.0001-0.1 mol normally with respect to 1 mol of aldehydes, 0.0005-0.05 mol is preferable and 0.001-0.02 mol is more preferable.

  The living cationic polymerization reaction is preferably performed in the presence of a suitable organic solvent, but may be performed in the absence. Examples of the organic solvent include aromatic hydrocarbon solvents such as benzene, toluene and xylene; propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, n-heptane, n-octane, isooctane and decane. Aliphatic hydrocarbon solvents such as hexadecane; halogenated hydrocarbon solvents such as methylene chloride, ethylene chloride, carbon tetrachloride; ether solvents such as diethyl ether, dibutyl ether, tetrahydrofuran (THF), ethylene glycol diethyl ether Can be mentioned. Of these, toluene, methylene chloride, and THF are preferable. You may use the said organic solvent individually or in combination of 2 or more types.

  The polymerization temperature in the living cation polymerization reaction varies depending on the type of polymerization initiator, monomer, and solvent used, but is usually -80 to 150 ° C, preferably -50 to 100 ° C, more preferably -20 to 80 ° C. The polymerization time varies depending on the polymerization initiator, monomer, solvent, reaction temperature, etc. used, but is usually about 10 minutes to 100 hours. In addition, the polymerization reaction can be suitably performed by either a batch method or a continuous method. The polymerization is stopped by adding a lower alcohol such as methanol or a lower alcohol solution to which a very small amount of a basic compound such as ammonia or amine is added if necessary. [A] The polymer component can be obtained by removing unreacted monomer, solvent and catalyst from the product by reprecipitation with methanol or the like, thin film evaporation method, column adsorption method or the like.

  [A] The content of the polymer component 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 solid content of the radiation-sensitive composition. [A] By making content of a polymer component into the said range, the said radiation sensitive composition can form the pattern which is excellent in LWR and pattern shape.

  [A] The polystyrene-reduced weight average molecular weight (Mw) of the polymer component by gel permeation chromatography (GPC) is not particularly limited, but is preferably 1,000 or more and 500,000 or less, and preferably 2,000 or more and 400,000 or less. More preferred. In addition, when the Mw of the [A] polymer is less than 1,000, the heat resistance when used as a resist tends to decrease. On the other hand, when the Mw of the [A] polymer exceeds 500,000, the sensitivity when used as a resist tends to decrease.

  [A] The ratio (Mw / Mn) of Mw to the number average molecular weight (Mn) in terms of polystyrene by GPC of the polymer component is usually from 1 to 5, preferably from 1 to 3, more preferably from 1 to 2. . By setting Mw / Mn in such a range, the photoresist film has excellent resolution performance.

  In addition, Mw and Mn of this specification use a GPC column (Tosoh, G2000HXL, G3000HXL, G4000HXL), flow rate of 1.0 ml / min, elution solvent tetrahydrofuran, column temperature of 40 ° C. It is a value measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under conditions.

<[B] Acid generator>
[B] The acid generator is a compound that generates an acid by light passing through a mask in an exposure process, which is one process of forming a resist pattern. The content form of the [B] acid generator in the radiation-sensitive composition is a part of the polymer even in the form of a compound as described later (hereinafter, this aspect is also referred to as “[B] acid generator”). Or both of these embodiments.

  [B] Examples of the acid generator include onium salt compounds, sulfonimide compounds, halogen-containing compounds, diazoketone compounds, sulfone compounds, sulfonic acid compounds, and diazomethane compounds. Among these [B] acid generators, onium salt compounds are preferred from the viewpoints of sensitivity and low contamination in the formation of fine patterns of sub-micron or less using far ultraviolet rays, X-rays, charged particle beams, EUV, and visible light. In forming a pattern of micron or more using ultraviolet light, it is preferable to mainly use a halogen-containing compound or a diazoketone compound from the viewpoint of cost and pattern physical properties.

  Examples of the onium salt compound include sulfonium salts (including tetrahydrothiophenium salts), iodonium salts, phosphonium salts, diazonium salts, pyridinium salts, and the like.

  Examples of the sulfonium salt include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, triphenylsulfonium 2-bicyclo [2.2.1] hept- 2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfonium perfluoro- n-octanesulfonate, 4-cyclohexylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept- -Yl-1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium par Fluoro-n-octanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenylphosphonium 1,1, Examples include 2,2-tetrafluoro-6- (1-adamantane carbonyloxy) -hexane-1-sulfonate. Of these, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate and triphenylphosphonium 1,1,2,2-tetrafluoro-6- (1-adamantane carbonyloxy) -hexane-1 -Sulfonate is preferred.

  Examples of the tetrahydrothiophenium salt include 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nona. Fluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophene Nitro 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium trifluoromethane Sulfonate, 1- (6-n-butoxynaphthalene-2 Yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (6-n-butoxynaphthalene- 2-yl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) ) Tetrahydrothiophenium trifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydro Thiophenium perfluoro-n-octance Phonates, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, etc. Can be mentioned. Of these, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium perfluoro -N-Octanesulfonate and 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate are preferred.

  Examples of the iodonium salt include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl- 1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t -Butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetra Le Oro ethanesulfonate. Of these, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate is preferred.

  Examples of the sulfonimide compound include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluoro-n-butanesulfonyloxy) bicyclo [ 2.2.1] Hept-5-ene-2,3-dicarboximide, N- (perfluoro-n-octanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3- Dicarboximide, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene -2,3-dicarboximide and the like. Of these, N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide is preferred.

  Examples of the halogen-containing compound include haloalkyl group-containing hydrocarbon compounds and haloalkyl group-containing heterocyclic compounds. Of these, 1,10-dibromo-n-decane, 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethane, phenyl-bis (trichloromethyl) -s-triazine, 4-methoxyphenyl- Bis (trichloromethyl) -s-triazine, styryl-bis (trichloromethyl) -s-triazine, naphthyl-bis (trichloromethyl) -s-triazine, 2- [2- (5-methylfuran-2-yl) ethenyl ] -Triazine derivatives such as -4,6-bis- (trichloromethyl) -s-triazine are preferred.

  Examples of the diazoketone compound include a 1,3-diketo-2-diazo compound, a diazobenzoquinone compound, a diazonaphthoquinone compound, and the like. Specific examples thereof include 1,2-naphthoquinonediazide-4-sulfonic acid ester compounds of phenols.

  Examples of the sulfone compound include β-ketosulfone compounds, β-sulfonylsulfone compounds, α-diazo compounds of these compounds, and the like. Specific examples thereof include 4-trisphenacylsulfone, mesitylphenacylsulfone, bis (phenacylsulfonyl) methane, and the like.

  Examples of the sulfonic acid compounds include alkyl sulfonic acid esters, haloalkyl sulfonic acid esters, aryl sulfonic acid esters, and imino sulfonates. Of these, benzoin tosylate, pyrogallol tris trifluoromethanesulfonate, o-nitrobenzyl trifluoromethanesulfonate, and o-nitrobenzyl p-toluenesulfonate are preferred.

  Examples of the diazomethane compound include bis (trifluoromethylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (phenylsulfonyl) diazomethane, and the like.

  These [B] acid generators tend to cause dissociation reaction of the acid-dissociable group and decomposition reaction of the acetal skeleton when the acid strength of the generated acid is strong, and the smaller acid structure size diffuses in the resist film. It is known that it is easy to do, and these can be selected and used as appropriate. [B] The acid generator may be used alone or in combination of two or more. [B] The amount used when the acid generator is an “agent” is the [A] polymer from the viewpoint of ensuring the sensitivity and lithography performance of the resist coating film formed from the radiation-sensitive composition. 0.01 mass part or more and 25 mass parts or less are preferable with respect to 100 mass parts of components, and 0.1 mass part or more and 20 mass parts or less are more preferable.

<Other optional components>
Other optional components that may be contained in the radiation-sensitive composition include [C] acid diffusion controller, [D] polymer containing fluorine atom, [E] additive, solvent, alicyclic skeleton. Examples of the compound include a surfactant, a surfactant, and a sensitizer. Hereinafter, each component will be described in detail.

<[C] acid diffusion controller>
The radiation-sensitive composition preferably further contains a [C] acid diffusion controller. This [C] acid diffusion controlling agent controls the diffusion phenomenon in the resist film of the acid generated from the [B] acid generator upon exposure, and suppresses an undesirable chemical reaction in the unexposed region. By blending such a [C] acid diffusion control agent, the storage stability of the resulting radiation-sensitive composition is improved, the resolution as a resist is further improved, and from exposure to heat treatment after exposure. The change in the line width of the resist pattern due to the fluctuation of the holding time (PED) of the resist can be suppressed, and a composition having extremely excellent process stability can be obtained.

  [C] As the acid diffusion controller, for example, a nitrogen-containing compound having an Nt-alkoxycarbonyl group is preferably used. Specifically, Nt-butoxycarbonyldi-n-octylamine, Nt-amyloxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, Nt-amyloxy Carbonyl di-n-nonylamine, Nt-butoxycarbonyldi-n-decylamine, Nt-amyloxycarbonyldi-n-decylamine, Nt-butoxycarbonyldicyclohexylamine, Nt-amyloxycarbonyldicyclohexylamine Nt-butoxycarbonyl-1-adamantylamine, Nt-amyloxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, Nt-amyloxycarbonyl-2-adamantylamine Nt-butoxycarbonyl-N-methyl-1 Adamantylamine, Nt-amyloxycarbonyl-N-methyl-1-adamantylamine, (S)-(-)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, (S)-(-)- 1- (t-amyloxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t- Amyloxycarbonyl) -2-pyrrolidinemethanol, Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-amyloxycarbonyl-4-hydroxypiperidine, Nt-butoxycarbonylpyrrolidine, Nt-amyloxycarbonyl Pyrrolidine, N, N′-di-t-butoxycarbonylpiperazine, N, N′-di-t-amyloxycarbonylpipe Gin, N, N-di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-amyloxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-4,4′-diaminodiphenylmethane, Nt-amyloxycarbonyl-4,4′-diaminodiphenylmethane, N, N′-di-t-butoxycarbonylhexamethylenediamine, N, N′-di-t-amyloxycarbonylhexamethylenediamine, N, N , N ′, N′-tetra-t-butoxycarbonylhexamethylenediamine, N, N, N ′, N′-tetra-t-amyloxycarbonylhexamethylenediamine, N, N′-di-t-butoxycarbonyl- 1,7-diaminoheptane, N, N′-di-t-amyloxycarbonyl-1,7-diaminoheptane, N, N '-Di-t-butoxycarbonyl-1,8-diaminooctane, N, N'-di-t-amyloxycarbonyl-1,8-diaminooctane, N, N'-di-t-butoxycarbonyl-1, 9-diaminononane, N, N′-di-t-amyloxycarbonyl-1,9-diaminononane, N, N′-di-t-butoxycarbonyl-1,10-diaminodecane, N, N′-di-t -Amyloxycarbonyl-1,10-diaminodecane, N, N'-di-t-butoxycarbonyl-1,12-diaminododecane, N, N'-di-t-amyloxycarbonyl-1,12-diaminododecane N, N′-di-t-butoxycarbonyl-4,4′-diaminodiphenylmethane, N, N′-di-t-amyloxycarbonyl-4,4′-diaminodiphenylmethane, N t-butoxycarbonylbenzimidazole, Nt-butoxycarbonylbenzimidazole, Nt-amyloxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenzimidazole, Nt-amyloxycarbonyl And compounds such as 2-phenylbenzimidazole.

  [C] In addition to the above compounds, for example, nitrogen-containing compounds such as tertiary amine compounds, quaternary ammonium hydroxide compounds, and nitrogen-containing heterocyclic compounds are used as the acid diffusion controller.

Examples of tertiary amine compounds include triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octyl. Tri (cyclo) alkylamines such as amine, cyclohexyldimethylamine, dicyclohexylmethylamine, and tricyclohexylamine;
Fragrances such as aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, 2,6-dimethylaniline, 2,6-diisopropylaniline Group amines;
Alkanolamines such as triethanolamine and N, N-di (hydroxyethyl) aniline;
N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, 1,3-bis [1- (4-aminophenyl) -1- Methylethyl] benzenetetramethylenediamine, bis (2-dimethylaminoethyl) ether, bis (2-diethylaminoethyl) ether and the like.

  Examples of the quaternary ammonium hydroxide compound include tetra-n-propylammonium hydroxide and tetra-n-butylammonium hydroxide.

  Examples of the nitrogen-containing heterocyclic compound include 2-phenyl-benzimidazole.

  Furthermore, as the [C] acid diffusion control agent, an onium salt compound that decomposes by exposure and loses basicity as acid diffusion controllability can be used. Specific examples of such an onium salt compound include a sulfonium salt compound represented by the following formula (5-1) and an iodonium salt compound represented by the following formula (5-2).

R ^{22 to} R ²⁶ in the above formulas (5-1) and (5-2) are each independently a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom.
Anb ⁻ represents OH ⁻ , R ²⁷ —COO ⁻ , R ²⁷ —SO ₃ ^— (wherein R ²⁷ independently represents an alkyl group, an aryl group, or an alkanol group), or the following formula: The anion represented by (5) is represented.

  Specific examples of the sulfonium salt compound and the iodonium salt compound include triphenylsulfonium hydroxide, triphenylsulfonium acetate, triphenylsulfonium salicylate, diphenyl-4-hydroxyphenylsulfonium hydroxide, diphenyl-4-hydroxyphenylsulfonium acetate. Diphenyl-4-hydroxyphenylsulfonium salicylate, bis (4-t-butylphenyl) iodonium hydroxide, bis (4-t-butylphenyl) iodonium acetate, bis (4-t-butylphenyl) iodonium hydroxide, Bis (4-t-butylphenyl) iodonium acetate, bis (4-t-butylphenyl) iodonium salicylate, 4-t- Tylphenyl-4-hydroxyphenyliodonium hydroxide, 4-t-butylphenyl-4-hydroxyphenyliodonium acetate, 4-t-butylphenyl-4-hydroxyphenyliodonium salicylate, bis (4-t-butylphenyl) iodonium Examples thereof include 10-camphor sulfonate, diphenyliodonium 10-camphor sulfonate, triphenylsulfonium 10-camphor sulfonate, and 4-t-butoxyphenyl diphenylsulfonium 10-camphor sulfonate.

  [C] The acid diffusion controller is a nitrogen having an Nt-alkoxycarbonyl group from the viewpoint of sensitivity and low volatility in the formation of fine patterns of submicron or less using far ultraviolet rays, X-rays, charged particle beams and EUV. Containing compounds and onium salt compounds are preferred, and in the formation of micron or larger patterns using visible light and ultraviolet light, tertiary amine compounds, quaternary ammonium hydroxide compounds, and nitrogen-containing heterocyclic compounds are mainly used from the viewpoint of cost and pattern physical properties. It is preferable to use for. In addition, [C] acid spreading | diffusion controlling agents can be used individually by 1 type or in mixture of 2 or more types. [C] The content ratio of the acid diffusion controller is preferably 10 parts by mass or less, and more preferably 0.1 parts by mass or more and 8 parts by mass or less with respect to 100 parts by mass of the polymer component [A]. When the amount used exceeds 10 parts by mass, the sensitivity as a resist tends to decrease.

<[D] Polymer containing fluorine atom>
The radiation-sensitive composition can further contain a polymer containing [D] fluorine atoms (hereinafter also referred to as “[D] polymer”). [D] A polymer is a polymer containing a fluorine atom, and it is preferable that a fluorine atom content rate is higher than a [A] polymer component. When the radiation-sensitive composition contains the [D] polymer, the hydrophobicity of the resist film is improved, and even when immersion exposure is performed, the substance elution is excellent, and the resist film, the immersion liquid, The receding contact angle can be sufficiently high, and there are effects such as no water droplets remaining when scanning exposure is performed at high speed. For this reason, it has utility as a material for immersion exposure, and [D] polymer is not only contained as one component of the radiation-sensitive composition of the present invention, but also [D] polymer on the photoresist film. The same hydrophobicity improving effect can be exhibited by forming a film of a simple substance.

[D] As an aspect of the polymer, for example, a structure in which a fluorinated alkyl group is bonded to the main chain;
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.

  As a monomer that gives a structure in which a fluorinated alkyl group is bonded to the main chain, for example, an α-trifluoromethyl acrylate compound, a β-trifluoromethyl acrylate compound, an α, β-trifluoromethyl acrylate compound, one or more types Examples thereof include compounds in which the hydrogen at the vinyl moiety is substituted with a fluorinated alkyl group such as a trifluoromethyl group.

  Monomers that give 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 side Examples thereof include ester compounds in which the chain is a fluorinated alkyl group or a derivative thereof, and one or more olefin side chains (sites not including a double bond) being a fluorinated alkyl group or a derivative thereof.

  Examples of the monomer that gives a structure in which a fluorinated alkyl group is bonded to the main chain and the side chain include α-trifluoromethylacrylic acid, β-trifluoromethylacrylic acid, α, β-trifluoromethylacrylic acid, and the like. Is a fluorinated alkyl group or its derivative ester compound. One or more vinyl moiety hydrogens are substituted with a fluorinated alkyl group such as a trifluoromethyl group. The hydrogen bonded to the double bond of one or more alicyclic olefin compounds is replaced with a fluorinated alkyl group such as a trifluoromethyl group, and the side chain is a fluorinated alkyl group or a derivative thereof. And the like. In addition, an alicyclic olefin compound shows the compound in which a part of ring is a double bond.

  [D] As a content rate of a polymer, 1 mass part-15 mass parts are preferable with respect to 100 mass parts of [A] polymer components, and 2 mass parts-10 mass parts are more preferable.

<Solvent>
The radiation-sensitive composition usually contains a solvent. The solvent is not particularly limited as long as it can dissolve at least the [A] polymer component, the [B] acid generator and other components. As the solvent, alcohol solvents, ether solvents, ketone organic solvents, amide solvents, ester organic solvents, hydrocarbon solvents and the like can be used.

Examples of alcohol solvents include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, tert-butanol, n-pentanol, i-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-heptadeci Monoalcohol solvents such as alcohol, furfuryl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, diacetone alcohol;
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 -Polyhydric alcohol solvents such as ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, polyhydric alcohol partial ether solvents such as dipropylene glycol monopropyl ether.

  Examples of ether solvents include diethyl ether, dipropyl ether, dibutyl ether, diphenyl ether, and tetrahydrofuran.

  Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-i-butyl ketone, methyl-n-pentyl ketone, ethyl-n-butyl ketone, methyl-n- Examples include ketone solvents such as hexyl ketone, di-i-butyl ketone, trimethylnonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, acetophenone, and the like. .

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

  Examples of ester solvents include diethyl carbonate, propylene carbonate, methyl acetate, ethyl acetate, γ-butyrolactone, δ-valerolactone, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, sec sec -Butyl, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, acetoacetic acid Methyl, ethyl acetoacetate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol acetate Non-n-butyl ether, propylene glycol monomethyl ether acetate, 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, glycol diacetate Methoxytriglycol acetate, ethyl propionate, n-butyl propionate, i-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, Examples include diethyl malonate, dimethyl phthalate, and diethyl phthalate.

Examples of hydrocarbon solvents include n-pentane, i-pentane, n-hexane, i-hexane, n-heptane, i-heptane, 2,2,4-trimethylpentane, n-octane, i-octane, and cyclohexane. , Aliphatic hydrocarbon solvents such as methylcyclohexane;
Fragrances such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, i-propylbenzene, diethylbenzene, i-butylbenzene, triethylbenzene, di-i-propylbenzene, n-amylnaphthalene Group hydrocarbon solvents and the like.

  These organic solvents may be used alone or in combination of two or more.

[Alicyclic skeleton compound]
An alicyclic skeleton compound is a component that exhibits an action of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like. Examples of the alicyclic skeleton compound include adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and 1-adamantanecarboxylic acid t-butyl; deoxycholic acid t-butyl, deoxycholic acid t-butoxycarbonylmethyl, Deoxycholic acid esters such as 2-ethoxyethyl deoxycholic acid; Lithocholic acid esters such as tert-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid, 2-ethoxyethyl lithocholic acid; 3- [2-hydroxy-2 , 2-bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane, 2-hydroxy-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] nonane, and the like.

[Surfactant]
Surfactants are components that have the effect of improving coatability, striation, developability, and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol diacrylate. In addition to nonionic surfactants such as stearate, the following trade names are KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (above, manufactured by Tochem Products), MegaFac F171, F173 (above, manufactured by Dainippon Ink & Chemicals), Fluorad FC430, FC431 ( As above, manufactured by Sumitomo 3M, Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (above, manufactured by Asahi Glass) ) And the like.

[Sensitizer]
A sensitizer absorbs the energy of radiation and transmits the energy to the [B] acid generator, thereby increasing the amount of acid produced. The “apparent” of the radiation-sensitive composition Has an effect of improving the sensitivity. Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines and the like.

<Method for preparing radiation-sensitive composition>
The said radiation sensitive composition can be prepared by mixing a [A] polymer component, a [B] acid generator, and another arbitrary component in a predetermined ratio, for example in the said solvent. The radiation-sensitive composition is usually dissolved in a solvent so that the total solid content is 1% by mass to 30% by mass, preferably 1.5% by mass to 25% by mass. It is prepared by filtering with a filter of about 2 μm.

<Pattern formation method>
A method for forming a resist pattern using the radiation-sensitive composition of the present invention will be described below.

A method for forming a resist pattern using the radiation-sensitive composition of the present invention,
(1) A step of forming a resist film of the radiation-sensitive composition on a substrate (hereinafter also referred to as “step (1)”),
(2) a step of irradiating at least a part of the resist film (hereinafter also referred to as “step (2)”); and (3) a step of developing the resist film irradiated with the radiation (hereinafter referred to as “step”). (Also referred to as (3))
Have Hereinafter, each process is explained in full detail.

According to the pattern forming method, since the radiation-sensitive composition is used, a pattern having excellent rectangularity with particularly few residue at the bottom of the pattern and reduced LWR can be provided.
Therefore, even with radiation such as i-line, KrF excimer laser, ArF excimer laser, EUV, etc., a fine pattern can be formed from the radiation-sensitive composition with high accuracy and stability, and further miniaturization will be made in the future. It can be suitably used for manufacturing semiconductor devices that are expected to progress.

[Step (1)]
In this step, the radiation-sensitive composition is applied onto a substrate such as silicon wafer, silicon dioxide, a wafer coated with an antireflection film, glass or the like by a coating means such as spin coating, cast coating, roll coating or ink jet coating. In order to form a resist film, the solvent in the composition is volatilized by pre-baking (PB) at a temperature of usually about 70 ° C. to 160 ° C. in some cases. The photoresist film may be formed by laminating a plurality of layers. The same radiation-sensitive composition may be overcoated twice or more, and a polymer containing fluorine on the formed photoresist film particularly in immersion exposure. In some cases, a fluororesin film layer containing [D] as a main component is formed.

[Step (2)]
In this step, the resist film formed in the step (1) is exposed by irradiation with radiation (in some cases through an immersion medium such as water). At this time, radiation is irradiated through a mask having a predetermined pattern. The radiation is appropriately selected from visible light, ultraviolet light, far ultraviolet light, X-rays, charged particle beams, EUV, etc. according to the line width of the target pattern. For example, far ultraviolet rays typified by ArF excimer laser (wavelength 193 nm) and KrF excimer laser (wavelength 248 nm) are preferable from the viewpoint of pattern formation on a submicron order, and EUV (extreme ultraviolet light) is used to form finer nano-order patterns. , A wavelength of 13.5 nm) can be preferably used. Further, since the effect of reducing the residue in the exposed portion is effective regardless of the light source, it can be applied even to micron order pattern formation using visible light. Subsequently, it is preferable to perform post-exposure baking (PEB). By this PEB, it becomes possible to smoothly advance the reaction of the acid generated from the [A] polymer component and the acid generator. The heating condition of PEB can be appropriately selected depending on the composition of the radiation-sensitive composition, but is usually about 50 ° C to 180 ° C.

[Step (3)]
In this step, a resist pattern is formed by removing the exposed portion from the exposed resist film. In the present invention, development is performed using a developer, and after development, washing with water and drying are performed. After PEB after exposure, heat treatment is performed at a higher temperature to volatilize the acid decomposition product in the exposed portion. A method of removing is possible. Of these methods, the heat treatment method is preferred.

  Examples of the developer used in the developing method using the developer include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, and di-n. -Propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7 -In addition to an alkaline aqueous solution in which at least one alkaline compound such as undecene and 1,5-diazabicyclo- [4.3.0] -5-nonene is dissolved, an organic solvent that does not dissolve polymer components such as methanol and butanol There.

  In the above heat treatment method, the reheating temperature in the case of reheating after PEB is preferably higher than that of PEB and lower than the softening point of the resist film because there is no deformation of the pattern shape. In addition, when the softening point of a resist film raises by heating, or when the thermal deformation of a resist film is permitted, it is not limited to this but is determined by a desired shape.

  In the case of performing immersion exposure, before the step (2), in order to protect the direct contact between the immersion liquid and the resist film, an immersion liquid insoluble immersion protective film is formed on the resist film. It may be provided. As the protective film for immersion, a solvent-peeling protective film that peels off with a solvent before the step (3) (see, for example, JP-A-2006-227632), a developer that peels off simultaneously with the development in the step (3) Any of peelable protective films (for example, see WO2005-069096, WO2006-035790, etc.) may be used.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer were measured using the GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation under the following conditions. Flow rate: 1.0 mL / min,
Elution solvent: tetrahydrofuran,
Column temperature: 40 ° C
Sample concentration: 0.2% by mass
Sample injection volume: 100 μL
Detector: Differential refractometer Standard material: Monodispersed polystyrene The dispersity (Mw / Mn) was calculated from the measurement results of Mw and Mn.

¹ H-NMR analysis and ¹³ C-NMR analysis were performed using a nuclear magnetic resonance apparatus (JEOL Ltd., JNM-EX270). The content of the structure derived from benzaldehyde, using a ^{1 H-NMR,} was determined by the area ratio of the peak and other peak of hydrogen of an aromatic ring. The content of the structure derived from milnalaldehyde was determined from the area ratio between the peak of hydrogen of mirutenal and other peaks.

<Synthesis of [A] Component>
[A] A component and the monomer used for the synthesis | combination of the [D] polymer mentioned later are shown below. Table 1 shows the characteristics of the synthesized polymer. In addition, "-" in Table 1 indicates that the content rate of the corresponding structural unit is not measured.

[Synthesis Example 1]
In a reaction vessel, toluene 2.96 mL, 1,4-dioxane 0.43 mL, compound (M-1) 0.3 g (50 mol%) as a vinyl ether derivative compound having an electron-withdrawing group, and compound as an aldehyde derivative compound (M-2) 0.3 g (50 mol%) was sequentially added. Thereafter, 0.5 mL of a 40 mM solution obtained by diluting a 200 mM dichloromethane solution of ethanesulfonic acid with toluene and 0.5 mL of a 40 mM solution of gallium chloride were added at −78 ° C. and reacted for 48 hours. In addition, when the amount of unreacted substances in the reaction solution was confirmed by gas chromatography, 0.03 g of the compound (M-2) was unreacted, and the polymerization conversion rate at this time was 94%. Next, the reaction was stopped using an ammoniacal methanol solution, and post-treatment operations such as extraction were performed to obtain 0.54 g of the polymer (A-1). ^{As a result of 1} H-NMR analysis (CDCl ₃ solvent), the content of the structural unit derived from the compound (M-2) was 47%. Mn of the polymer (A-1) was 17,300, and Mw / Mn was 1.12. Molecular weight analysis was carried out in terms of polystyrene by GPC, and Mw and Mw / Mn were measured using both RI and UV detectors. The results obtained using both detection groups were in good agreement, and the compound ( It was confirmed that the benzaldehyde unit derived from M-2) was uniformly incorporated into the polymer (A-1).

[Synthesis Example 2]
In a reaction vessel, toluene 2.96 mL, 1,4-dioxane 0.43 mL, compound (M-3) 0.36 g (50 mol%) as a vinyl ether derivative compound having an alicyclic group, compound as an aldehyde derivative compound ( M-2) 0.3 g (50 mol%) was sequentially added. Thereafter, 0.5 mL of a 40 mM solution obtained by diluting a 200 mM dichloromethane solution of ethanesulfonic acid with toluene, 0.5 mL of a 40 mM solution obtained by diluting a 200 mM dichloromethane solution of ethanesulfonic acid with toluene, and 0.5 mL of a 40 mM solution of tin tetrachloride are −20 The mixture was added at 0 ° C. and reacted for 20 hours. In addition, when the amount of unreacted substances in the reaction solution was confirmed by gas chromatography, 0.028 g of the compound (M-2) was unreacted, and the polymerization conversion rate at this time was 96%. Next, the reaction was stopped using an ammoniacal methanol solution, and post-treatment operations such as extraction were performed to obtain 0.62 g of a polymer (A-2). ^{As a result of 1} H-NMR analysis (CDCl ₃ solvent), the content of the structural unit derived from the compound (M-2) was 43%. Mn of the polymer (A-2) was 12,000, and Mw / Mn was 1.2. Molecular weight analysis was carried out in terms of polystyrene by GPC, and Mw and Mw / Mn were measured using both RI and UV detectors. The results obtained using both detection groups were in good agreement, and the compound ( It was confirmed that the benzaldehyde unit derived from M-2) was uniformly incorporated into the polymer (A-2).

[Synthesis Example 3]
Under a nitrogen flow, in toluene (the total system is 5 mL), 0.54 mL of 1,4-dioxane, 0.1 g (20 mol%) of a compound (M-4) as a vinyl ether derivative compound having a heterocyclic group , 0.1 g (30 mol%) of a compound (M-1) as a vinyl ether derivative compound having an electron-withdrawing group, 0.2 g (50 mol%) of a compound (M-2) as an aldehyde derivative compound, initiator system As a solution, 0.50 mL of 40 mM toluene solution of CH ₃ CH (iBu) OCOCH ₃ and 0.5 mL of 40 mM solution of ethanesulfonic acid in 200 mM dichloromethane diluted with toluene were added in this order, and finally 0.50 mL of 40 mM toluene solution of gallium chloride was added. The living cationic polymerization was carried out at 30 ° C. for 2.5 hours. When the amount of unreacted substances in the reaction solution was confirmed by gas chromatography, 0.05 g of BzA was unreacted, and the polymerization conversion rate at this point was 88%. Next, the reaction was stopped using an ammoniacal methanol solution, and post-treatment operations such as extraction were performed to obtain 0.34 g of a polymer (A-3). ^{As a result of 1} H-NMR analysis (CDCl ₃ solvent), the content of the structural unit derived from the compound (M-2) was 43%. Mn of the polymer (A-3) was 6,400, and Mw / Mn was 1.2. Molecular weight analysis was carried out in terms of polystyrene by GPC, and Mw and Mw / Mn were measured using both RI and UV detectors. The results obtained using both detection groups were in good agreement, and the compound ( It was confirmed that the benzaldehyde unit derived from M-2) was uniformly incorporated into the polymer (A-3).

[Synthesis Example 4]
Under nitrogen flow, 0.19 g (20 mol%) of a compound (M-5) as a vinyl ether derivative compound having an acid-dissociable group in toluene (the total system is 5 mL), having a chain hydrocarbon group Compound (M-6) 0.12 g (30 mol%) as a vinyl ether derivative compound, Compound (M-7) 0.28 g (50 mol%) as an aldehyde derivative compound, 0.50 mL of 1,4-dioxane, start As an agent system, 0.50 mL of a 40 mM toluene solution of CH ₃ CH (iBu) OCOCH ₃ , 0.3 mL of a 40 mM solution obtained by diluting a 200 mM dichloromethane solution of ethanesulfonic acid with toluene were added in this order, and finally a 200 mM toluene solution of FeCl ₃ was added. .50 mL was added and living cationic polymerization was carried out at 0 ° C. for 5 hours. In addition, when the amount of unreacted substances in the reaction solution was confirmed by gas chromatography, 0.06 g of the compound (M-5) was unreacted, and the polymerization conversion rate at this point was 90%. Next, the reaction was stopped using an ammoniacal methanol solution, and post-treatment operations such as extraction were performed to obtain 0.48 g of the polymer (A-4). ^{As a result of 1} H-NMR analysis (CDCl ₃ solvent), the MYR content in A-4 calculated from the olefin unit derived from the compound (M-7) MYR was 53%. Mn of the polymer (A-4) was 8,200, and Mw / Mn was 1.3. Molecular weight analysis was carried out in terms of polystyrene by GPC, and Mw and Mw / Mn were measured using both RI and UV detectors. The results obtained using both detection groups were in good agreement, and the compound ( It was confirmed that the mirutenal unit derived from M-7) was uniformly incorporated into the polymer (A-4).

[Synthesis Example 5]
Under a nitrogen stream, 0.19 g (20 mol%) of a compound (M-5) as a vinyl ether derivative compound having an acid-dissociable group in toluene (the total system is 5 mL), having a chain hydrocarbon group 0.12 g (30 mol%) of the compound (M-6) as a vinyl ether derivative compound, 0.25 g (50 mol%) of cinnamaldehyde (M-10) as an aldehyde derivative compound, CH ₃ CH ( iBu) 0.50 mL of a toluene solution of OCOCH ₃ (40 mM) was added in this order, and finally 0.50 mL of a toluene solution of FeCl ₃ (200 mM) was added, and the reaction was performed at 0 ° C. for 5 hours, and an ammoniacal methanol solution was used. The reaction was stopped. When the amount of unreacted substances in the reaction solution was confirmed by gas chromatography, 0.05 g of CynA was unreacted, and the polymerization conversion rate at this point was 91%.
Post-treatment operations such as extraction were performed to obtain 0.48 g of a solid (A-5). ^{As a result of 1} H-NMR analysis (CDCl ₃ solvent), 40 mol% of units derived from cinnamoyl aldehyde were contained. The number average molecular weight of this polymer was 10,200, and the weight average molecular weight / number average molecular weight was 1.2. Molecular weight analysis was performed in terms of polystyrene by GPC, and when Mw and Mw / Mn were measured using both RI and UV detectors, the results obtained using both detection groups were in good agreement, and cinnamaldehyde It was confirmed that the originating aldehyde unit was uniformly incorporated into the polymer (A-5).

[Synthesis Example 6]
In a 30 mL flask under nitrogen flow, dry toluene 3 mL, dry ethyl acetate 0.5 mL, 1-butoxyethyl acetate 40 mM toluene solution 0.5 mL, compound (M-6) 0 as a vinyl ether derivative compound having a chain hydrocarbon group 0 .2 g (50 mol%) and 0.12 g (50 mol%) of the compound (M-1) as a vinyl ether derivative compound having an electron-withdrawing group were added and cooled to 0 ° C., then Et _1.5 AlCl _1.5 0.5 mL of 200 mM toluene solution was added and stirred at 0 ° C. After 2 hours, 1 mL of methanol was added to stop the reaction. The reaction solution was diluted with toluene and washed with water, and then the solvent was distilled off from the organic phase to obtain a polymer (a-1). Mw of the polymer (a-1) was 30,200, and Mw / Mn was 1.18.

<[D] Synthesis of polymer>
[Synthesis Example 7]
Methacrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-butyl) ester compound (M-8) 46.81 g (85 mol%) and initiator 2,2′- A monomer solution in which 4.53 g of azobis- (methyl 2-methylpropionate) was dissolved in 40.00 g of isopropanol was prepared. Meanwhile, 50 g of isopropanol was charged into a 200 mL three-necked flask equipped with a thermometer and a dropping funnel, and purged with nitrogen for 30 minutes. After purging with nitrogen, the solution in the flask was heated to 80 ° C. with stirring. Next, the monomer solution prepared beforehand was dripped over 2 hours using the dropping funnel. After completion of the dropping, the reaction was further continued for 1 hour, and 10 g of an isopropanol solution of 3.19 g (15 mol%) of the vinyl sulfonic acid compound (M-9) was added dropwise over 30 minutes. Then, after reacting for further 1 hour, it cooled to 30 degrees C or less, and obtained the copolymer liquid.
The obtained copolymer solution was concentrated to 150 g, then transferred to a separatory funnel, and 50 g of methanol and 600 g of n-hexane were added thereto for separation and purification. After separation, the lower layer solution was recovered. This lower layer solution was diluted with isopropanol to 100 g, and again transferred to a separatory funnel. Thereafter, 50 g of methanol and 600 g of n-hexane were put into the above separatory funnel, followed by separation and purification, and the lower layer solution was recovered. The recovered lower layer solution was replaced with 4-methyl-2-pentanol, and the total amount was adjusted to 250 g. After the adjustment, 250 g of water was added for separation and purification, and the upper layer liquid was recovered. The recovered upper layer liquid was substituted with 4-methyl-2-pentanol to obtain a polymer solution. The copolymer (D-1) contained in the obtained polymer solution had Mw of 10,010, Mw / Mn of 1.55, and the yield was 75%. As a result of ¹³ C-NMR, the content of the structural unit derived from the compound (M-8) and the structural unit derived from the compound (M-9) contained in this copolymer was 98: 2. (Mol%).

<Preparation of radiation-sensitive composition>
The [B] acid generator, [C] acid diffusion controller and solvent used for the preparation of the radiation sensitive composition are shown below.

<[B] Acid generator>
(B-1) to (B-4): Compounds represented by the following formulae

<[C] acid diffusion controller>
(C-1) to (C-4): a compound represented by the following formula

<Solvent>
E-1: Propylene glycol monomethyl ether acetate E-2: Tetrahydrofuran

[Example 1]
50 parts by mass of polymer component (A-1), 50 parts by mass of polymer component (A-2), 10 parts by mass of acid generator (B-1), 4 parts by mass of acid diffusion controller (C-3), heavy 4 parts by mass of combined (D-1), 2,050 parts by mass of solvent (E-1) and 450 parts by mass of (E-2) were mixed, and the resulting mixed solution was filtered with a filter having a pore size of 0.2 μm. A radiation sensitive composition was prepared.

[Example 5]
10 parts by mass of polymer component (A-1), 90 parts by mass of polymer component (A-3), 7 parts by mass of acid generator (B-1), 3 parts by mass of acid diffusion controller (C-2), solvent (E-1) 2,050 parts by mass and (E-2) 450 parts by mass were mixed, and the resulting mixed solution was filtered with a filter having a pore size of 0.2 μm to prepare a radiation-sensitive composition. In addition, 100 parts by mass of the polymer (D-1) and 9,000 parts by mass of the solvent 4-methyl-2-pentanol were mixed to obtain a solution having a solid content concentration of 1.1%. The mixture was filtered through a 2 μm filter to prepare a composition for top coat.

[Examples 2 to 4, 6, 7 and Comparative Example 1]
Each radiation-sensitive composition was prepared in the same manner as in Example 1 except that the types and amounts of each component shown in Table 2 were used. In Table 2, “-” indicates that the corresponding component was not used.

[Examples 8 and 9]
The polymer component, acid generator and acid diffusion controller shown in Table 2 were mixed with 800 parts by mass of the solvent (E-1) and 150 parts by mass of (E-2), and the resulting mixed solution was mixed with a pore size of 0.5 μm. A radiation-sensitive composition was prepared by filtration using a filter.

<Formation of resist pattern>
Using each of the radiation sensitive compositions of Examples 1 to 9 and Comparative Example 1, patterns were formed according to the following pattern forming methods 1 to 6.

[Pattern Forming Method-1]
As a substrate, a 12-inch silicon wafer having a lower layer antireflection film (ARC66, manufactured by Brewer Science) with a film thickness of 50 nm formed on the surface was used. A resist film having a film thickness of 75 nm was formed on each of the lower antireflection films using each radiation sensitive composition, and PB was performed at 100 ° C. for 60 seconds. On this resist film, Lithius Pro-i (manufactured by Tokyo Electron Co., Ltd.) was used as needed, and a composition containing [D] polymer was applied by spin coating, and PB was applied at 90 ° C. on a hot plate. A top coat film having a thickness of 10 nm was formed. Next, this resist film was masked for pattern formation of 50 nm Line 100 nm Pitch using an ArF excimer laser immersion exposure apparatus (NSR S610C, manufactured by NIKON) under the conditions of NA = 1.3, ratio = 0.800, Annular. Exposed through pattern. After exposure, PEB was performed at 95 ° C. for 60 seconds. Thereafter, development was performed at 23 ° C. for 60 seconds using a 2.38 mass% tetramethylammonium hydroxide aqueous solution, followed by washing with water and drying to form a positive resist pattern. In addition, the sensitivity evaluation in the case of forming a pattern by this method was performed as follows. That is, an exposure amount at which a portion exposed through a mask pattern for forming a pattern of 50 nm Line 100 nm Pitch forms a Line having a line width of 50 nm is an optimum exposure amount (Eop), and this optimum exposure amount is a sensitivity (mJ / cm ² ). . A scanning electron microscope (Hitachi High-Technologies Corporation, CG4000) was used for measuring the line width.

[Pattern Forming Method-2]
As a substrate, an 8-inch silicon wafer having a lower layer antireflection film (DUV42-6, manufactured by Nissan Chemical Industries, Ltd.) having a film thickness of 60 nm formed on the surface was used. In addition, the semiconductor manufacturing apparatus (CLEAN TRACK ACT8, Tokyo Electron make) was used for formation of this antireflection film.
Next, each radiation sensitive composition was spin-coated on the substrate using the semiconductor manufacturing apparatus, and PB was performed at 85 ° C. for 60 seconds to form a resist film having a thickness of 500 nm. Next, this resist film was coated with 100% coverage under the conditions of NA = 0.68, σ = 0.75-1 / 2 annular illumination using a KrF excimer laser exposure apparatus (NSR S203B, manufactured by NIKON). It exposed through the photomask which has a pattern of 250 nmLine500nmPitch line and space. After exposure, PEB was performed at 85 ° C. for 60 seconds. Thereafter, development was performed at 23 ° C. for 60 seconds using a 2.38 mass% tetramethylammonium hydroxide aqueous solution, followed by washing with water and drying to form a positive resist pattern. In addition, the sensitivity evaluation in the case of forming a pattern by this method was performed as follows. That is, an exposure amount at which a portion exposed through a mask pattern for pattern formation of 250 nm Line 500 nm Pitch forms Line having a line width of 250 nm is an optimum exposure amount (Eop), and this optimum exposure amount is a sensitivity (mJ / cm ² ). . A scanning electron microscope (Hitachi High-Technologies Corporation, S-9380) was used for measuring the line width.

[Pattern Forming Method-3]
As a substrate, an 8-inch silicon wafer having a 77 nm-thick lower layer antireflection film (ARC29A, manufactured by Brewer Science) on the surface was used. In addition, the semiconductor manufacturing apparatus (CLEAN TRACK ACT8, Tokyo Electron make) was used for formation of an antireflection film. Next, each radiation sensitive composition was spin-coated on the substrate using the semiconductor manufacturing apparatus, and PB was performed at 90 ° C. for 60 seconds to form a resist film having a thickness of 60 nm. A line-and-space pattern (1L1S) having a line width of 50 nm was formed on the resist film by using a simple electron beam drawing apparatus (HL800D, manufactured by Hitachi, output: 50 KeV, current density: 5.0 amperes / cm ² ). An electron beam was irradiated through a photomask having). After performing PEB at 80 ° C. for 60 seconds, development was performed at 23 ° C. for 60 seconds using a 2.38 mass% tetramethylammonium hydroxide aqueous solution, followed by washing with water and drying to form a positive pattern. In addition, the sensitivity evaluation in the case of forming a pattern by this method was performed as follows. That is, the exposure amount for forming a line-and-space pattern (1L1S) having a line width of 50 nm with a one-to-one line width was defined as the optimum exposure amount, and this optimum exposure amount was defined as sensitivity (μC / cm ² ). A scanning electron microscope (S-9380, manufactured by Hitachi High-Technologies Corporation) was used for measuring the line width.

[Pattern Forming Method-4]
As a substrate, an 8-inch silicon wafer having a lower layer antireflection film (DUV42-6, manufactured by Nissan Chemical Industries, Ltd.) having a film thickness of 60 nm formed on the surface was used. In addition, the semiconductor manufacturing apparatus (CLEAN TRACK ACT8, Tokyo Electron make) was used for formation of this antireflection film.
Next, each radiation sensitive composition was spin-coated on the substrate using the semiconductor manufacturing apparatus, and PB was performed at 85 ° C. for 60 seconds to form a resist film having a thickness of 500 nm. Next, this resist film was coated with 100% coverage under the conditions of NA = 0.68, σ = 0.75-1 / 2 annular illumination using a KrF excimer laser exposure apparatus (NSR S203B, manufactured by NIKON). It exposed through the photomask which has a pattern of 250 nmLine500nmPitch line and space. After the exposure, PEB was performed at 85 ° C. for 60 seconds, and then heated at 130 ° C. for 2 minutes to form a pattern. In addition, the sensitivity evaluation in the case of forming a pattern by this method was performed as follows. That is, an exposure amount at which a portion exposed through a mask pattern for pattern formation of 250 nm Line 500 nm Pitch forms Line having a line width of 250 nm is an optimum exposure amount (Eop), and this optimum exposure amount is a sensitivity (mJ / cm ² ). . A scanning electron microscope (Hitachi High-Technologies Corporation, S-9380) was used for measuring the line width.

[Pattern Forming Method-5]
A 6-inch silicon wafer was spin-coated with a radiation sensitive composition using a spin coater (MS-A200, manufactured by Mikasa Co., Ltd.), heated at 100 ° C. for 60 seconds using a hot plate, and a uniform resist film having a thickness of 5 μm. Was made. Then, using an aligner (MAS-150 manufactured by Suss Mitotec), exposure was performed through a pattern mask of 5 μm Line 10 μm Pitch. Ultraviolet rays from a high-pressure mercury lamp were irradiated without particularly providing a filter, and the amount of light irradiated at a wavelength of 350 nm was used as the exposure amount. After the exposure, PEB was carried out at 90 ° C. for 60 seconds, followed by immersion development at 23 ° C. for 3 minutes using an aqueous 2.38 wt% tetramethylammonium hydroxide solution, washed with water, and dried to form a pattern. Evaluation of sensitivity when forming a pattern by this method was performed as follows. That is, an exposure amount at which a portion exposed through a mask pattern for pattern formation of 5 μM Line 10 μm Pitch forms a line having a line width of 5 μm is an optimal exposure amount (Eop), and this optimal exposure amount is a sensitivity (mJ / cm ² ). . A scanning electron microscope (Hitachi High-Technologies Corporation, S-9380) was used for measuring the line width.

[Pattern Formation Method-6]
A resist film was formed and exposed in the same manner as in Pattern Forming Method-5. After the exposure, PEB was performed at 90 ° C. for 60 seconds, and then heated at 150 ° C. for 2 minutes to form a pattern. Evaluation of sensitivity when forming a pattern by this method was performed as follows. That is, an exposure amount at which a portion exposed through a mask pattern for pattern formation of 5 μM Line 10 μm Pitch forms a line having a line width of 5 μm is an optimal exposure amount (Eop), and this optimal exposure amount is a sensitivity (mJ / cm ² ). . A scanning electron microscope (Hitachi High-Technologies Corporation, S-9380) was used for measuring the line width.

<Evaluation>
The following evaluation was performed about each pattern obtained according to the said pattern formation method using each radiation sensitive composition. In addition, the pattern formation method used about each radiation sensitive composition, PB and PEB conditions, and each evaluation result are shown according to Table 3. FIG. Note that “*” in Table 3 indicates that the evaluation could not be performed because a pattern was not obtained. Moreover, in the pattern formation method, the number with ^(T) in the number indicates the case where the top coat is applied to the upper layer of the resist film formed using the radiation-sensitive composition.

[sensitivity]
The sensitivity of each radiation-sensitive composition was measured by the method described in each pattern forming method.

[LWR]
A resist pattern was formed according to each of the above pattern forming methods, and Eop was measured. A line pattern having the same size as the mask pattern formed by the Eop was observed from above the pattern, and the line width was measured at 10 arbitrary points. The 3-sigma value (variation) of the measured line width was defined as LWR (nm). When the value of LWR was 150 nm or less for a 5 μm pattern, 10 nm or less for a 250 nm pattern, and 6 nm or less for a 50 nm pattern, it was evaluated as good.

[Pattern shape]
The cross-sectional shape of the line and space pattern obtained by each pattern forming method was observed. A case where the rectangularity is high is good, a case where the rectangularity is low such as a top round shape, a T-top shape or the like, and a case where the pattern cannot be formed are regarded as defective. In addition, Hitachi High-Technologies S-4800 was used for observation of a cross-sectional shape.

  As shown in Table 3, the radiation-sensitive composition of the present invention can form a good pattern with reduced LWR and excellent rectangularity, compared with the radiation-sensitive composition of the comparative example. Was found to be fully satisfied. Further, from Examples 4, 6 and 9, it was revealed that the radiation sensitive composition can form a good pattern only by heating following PEB without going through a development step with an alkaline developer.

  The radiation-sensitive composition of the present invention is suitably used in the formation of resist patterns in the lithography process of various electronic devices such as semiconductor devices and liquid crystal devices.

Claims (8)

[A] A polymer component having a repeating unit (I) represented by the following formula (1), and [B] a radiation-sensitive composition containing a radiation-sensitive acid generator.

(In Formula (1), R ¹ and R ² are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ³ is a single bond or a chain having 1 to 10 carbon atoms. X is a monovalent organic group, R ^{4 to} R ⁶ are each independently a hydrogen atom, a chain hydrocarbon group having 1 to 10 carbon atoms, or a carbon group having 6 to 20 carbon atoms. It is an aromatic hydrocarbon group, provided that at least one of R ^{4 to} R ⁶ is a chain hydrocarbon group having 1 to 10 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms. Any of ⁵ and R ⁶ and R ⁴ may be bonded to each other to form a ring structure having 5 to 20 carbon atoms. 2. The radiation-sensitive composition according to claim 1, wherein any one of R ⁵ and R ⁶ and R ⁴ are bonded to each other to form a ring structure having 5 to 20 carbon atoms.   [A] The radiation-sensitive composition according to claim 1 or 2, wherein the polymer components have the same or different polymers and the Xs have different repeating units (I).   The radiation-sensitive composition according to claim 3, wherein the different Xs are an electron-withdrawing group and an alicyclic group. The radiation-sensitive composition according to claim 4, wherein the alicyclic group is a group represented by the following formula (2).

(In the formula ^{(2), R} 7 ~R ¹⁸ are each independently a hydrogen atom, a deuterium atom, ^.A 1 to A ⁴ represents a hydrocarbon group having a halogen atom or 1 to 15 carbon atoms are each independently And one kind selected from the group consisting of a hydrogen atom, a deuterium atom, a halogen atom, a hydrocarbon group having 1 to 15 carbon atoms, or a boron atom, a nitrogen atom, an oxygen atom, a silicon atom, a phosphorus atom and a sulfur atom. It is an organic group containing the above atoms, m is an integer of 0 to 2. However, when m is 2, a plurality of R ^{13 to} R ¹⁸ may be the same or different. A plurality of groups ^{7 to} R ¹⁸ and A ^{1 to} A ⁴ may be bonded to form an alicyclic structure (* represents a bonding site with R ³ in the above formula (1).)   [A] The radiation sensitive composition according to any one of claims 1 to 5, wherein the content of the polymer component is 70% by mass or more of the total solid content. (1) A resist film forming step of forming a resist film on a substrate using the radiation-sensitive composition according to any one of claims 1 to 6;
(2) An exposure step of exposing the resist film, and (3) a pattern forming method including a developing step of developing the exposed resist film.   The pattern forming method according to claim 7, wherein the developing step is a step of heating the exposed resist film.