JP4834504B2 - Positive photosensitive composition and pattern forming method using the same - Google Patents

Description

  The present invention relates to a positive photosensitive composition used in a semiconductor manufacturing process such as an IC, a circuit board such as a liquid crystal or a thermal head, and other photofabrication processes, and a pattern forming method using the same. is there. More specifically, the present invention relates to a positive photosensitive composition suitable for use as an exposure light source such as far ultraviolet rays of 250 nm or less, preferably 220 nm or less, and an irradiation source using an electron beam, and a pattern forming method using the same.

  The chemically amplified photosensitive composition generates an acid in the exposed area by irradiation with radiation such as far ultraviolet light, and the acid-catalyzed reaction causes the solubility of the active radiation irradiated area and non-irradiated area in the developer. This is a pattern forming material for changing the pattern to form a pattern on the substrate.

  When a KrF excimer laser is used as an exposure light source, a resin having a basic skeleton of poly (hydroxystyrene) having a small absorption mainly in the 248 nm region is used as a main component. A pattern is formed, which is a better system than the conventional naphthoquinone diazide / novolak resin system.

On the other hand, when a further short wavelength light source, for example, ArF excimer laser (193 nm) is used as the exposure light source, the compound having an aromatic group essentially shows a large absorption in the 193 nm region. It wasn't.
For this reason, an ArF excimer laser resist containing a resin having an alicyclic hydrocarbon structure has been developed. Various improvements have been made in resists for ArF excimer lasers. For example, in Patent Document 1, Patent Document 2, and Patent Document 3, in a repeating unit having an alicyclic acid-decomposable group, the main chain and acid decomposition are performed. Various properties have been improved by introducing a repeating unit having a spacer moiety between the sex groups.
However, from the viewpoint of overall performance as a resist, it is actually difficult to find an appropriate combination of resin, photoacid generator, additive, solvent, etc. to be used, and the line width is 100 nm or less. When forming such a fine pattern, even if the resolution performance is excellent, the formed line pattern collapses, and the problem of pattern collapse that causes defects during device manufacturing, and the line edge of the line pattern It was very difficult to satisfy multiple performances such as roughness performance and good pattern profile at the same time, and improvements were required.
Here, the line edge roughness means that the resist line pattern and the edge of the substrate interface exhibit irregular shapes in a direction perpendicular to the line direction due to the characteristics of the resist. When this pattern is observed from directly above, the edges appear to be uneven (± several nm to several tens of nm). Since the unevenness is transferred to the substrate by an etching process, if the unevenness is large, an electrical characteristic defect is caused and the yield is lowered.

JP 2005-331918 A Japanese Patent Laid-Open No. 2004-184637 JP 2003-330192 A

  An object of the present invention is to provide a positive photosensitive composition capable of forming a pattern having a good profile with improved pattern collapse and line edge roughness performance even in the formation of a fine pattern of 100 nm or less, and a pattern forming method using the same Is to provide.

一般式（Ｉ）に於いて、
Ｘａ ₁ は、水素原子、アルキル基、シアノ基又はハロゲン原子を表す。
Ｒｙ ₁ 〜Ｒｙ ₃ は、各々独立に、アルキル基又はシクロアルキル基を表す。Ｒｙ ₁ 〜Ｒｙ ₃ の内の少なくとも２つが結合して単環又は多環の環状炭化水素構造を形成してもよい。
Ｚは、２価の鎖状炭化水素基を表す。
２．
（Ａ）成分の化合物が、活性光線又は放射線の照射により、下記一般式（Ｓ１）で表されるスルホン酸を発生する化合物であることを特徴とする上記１に記載のポジ型感光性組成物。

一般式（Ｓ１）に於いて、
Ｒｆは、炭素数２又は３のフッ素置換されたアルキレン基を表す。
Ａ ₁ は、単結合又はヘテロ原子を有する２価の連結基を表す。
Ｂ ₁ は、水素原子、フッ素原子、炭化水素構造を有する１価の有機基、スルホン酸基、カルボキシル基、水酸基又はシアノ基を表す。
３．
（Ａ）成分の化合物が、活性光線又は放射線の照射により炭素数２又は３のパーフロロアルカンスルホン酸を発生する化合物であることを特徴とする上記１又は２に記載のポジ型感光性組成物。
４．
（Ｂ）成分の樹脂が、更に、ラクトン基、水酸基、シアノ基及びアルカリ可溶性基から選ばれる少なくとも１種類を有する繰り返し単位を有することを特徴とする上記１〜３のいずれか一項に記載のポジ型感光性組成物。
５．
（Ｂ）成分の樹脂が、前記ラクトン基を有する繰り返し単位を有し、該繰り返し単位が、下記一般式（ＬＣ１−４）で表されるラクトン構造を有する繰り返し単位であることを特徴とする上記４に記載のポジ型感光性組成物。

一般式（ＬＣ１−４）に於いて、
Ｒｂ ₂ は、置換基を表す。
ｎ _２ は、０〜４の整数を表す。ｎ _２ が２以上の時、複数存在するＲｂ ₂ は、同一でも異なっていてもよく、また、複数存在するＲｂ ₂ 同士が結合して環を形成してもよい。
６．
（Ｂ）成分の樹脂が、更に、下記一般式（ＩＩ）で表される繰り返し単位を有することを特徴とする上記１〜５のいずれか一項に記載のポジ型感光性組成物。

一般式（ＩＩ）に於いて、
Ｘａ ₁ は、水素原子、アルキル基、シアノ基又はハロゲン原子を表し、一般式（Ｉ）に於けるＸａ ₁ と同様のものである。
Ｒｘ ₁ 〜Ｒｘ ₃ は、それぞれ独立に、アルキル基又はシクロアルキル基を表す。Ｒｘ ₁ 〜Ｒｘ ₃ の２つが結合して、シクロアルキル基を形成してもよい。
７．
（Ａ）成分の化合物を２種以上含有する、又は、（Ａ）成分の化合物以外の、活性光線又は放射線の照射により、酸を発生する化合物を更に含有することを特徴とする上記１〜６のいずれか一項に記載のポジ型感光性組成物。
８．
（Ａ）成分の化合物を２種以上含有し、該（Ａ）成分の化合物のうちの２つの化合物の各々が活性光線又は放射線の照射により発生する酸は、水素原子を除く全原子数が互いに２以上異なる２種の有機酸であることを特徴とする上記７に記載のポジ型感光性組成物。
９．
上記１〜８のいずれか一項に記載のポジ型感光性組成物により形成したレジスト膜。
１０．
上記９に記載のレジスト膜を露光、現像する工程を含むことを特徴とするパターン形成方法。
１１．
前記露光が液浸露光である、上記１０に記載のパターン形成方法。
尚、本発明は上記１〜１１に記載の構成を有するが、以下、その他についても参考のため記載した。 The present invention is as follows.
1.
(A) a compound capable of generating a sulfonic acid having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms upon irradiation with actinic rays or radiation, and (B) the following general formula Resin having an acid-decomposable repeating unit represented by (I) and having an increased dissolution rate in an alkaline developer by the action of an acid
A positive photosensitive composition comprising:

In general formula (I),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
Ry ₁ to Ry ₃ each independently represents an alkyl group or a cycloalkyl group. At least two members out of Ry _{1 to} Ry ₃ may be bonded to form a monocyclic or polycyclic hydrocarbon structure.
Z represents a divalent chain hydrocarbon group.
2.
2. The positive photosensitive composition as described in 1 above, wherein the compound of component (A) is a compound that generates a sulfonic acid represented by the following general formula (S1) upon irradiation with actinic rays or radiation. .

In the general formula (S1),
Rf represents a fluorine-substituted alkylene group having 2 or 3 carbon atoms.
A ₁ represents a divalent linking group having a single bond or a hetero atom.
B ₁ represents a hydrogen atom, a fluorine atom, a monovalent organic group having a hydrocarbon structure, a sulfonic acid group, a carboxyl group, a hydroxyl group or a cyano group.
3.
The positive photosensitive composition as described in 1 or 2 above, wherein the component (A) is a compound that generates perfluoroalkanesulfonic acid having 2 or 3 carbon atoms upon irradiation with actinic rays or radiation. .
4).
(B) The resin as component further has a repeating unit having at least one kind selected from a lactone group, a hydroxyl group, a cyano group, and an alkali-soluble group. Positive photosensitive composition.
5.
The resin of the component (B) has a repeating unit having the lactone group, and the repeating unit is a repeating unit having a lactone structure represented by the following general formula (LC1-4). 4. The positive photosensitive composition according to 4.

In the general formula (LC1-4),
Rb ₂ represents a substituent.
n ₂ represents an integer of 0-4. When n ₂ is 2 or more, a plurality of Rb ₂ may be the same or different, and a plurality of Rb ₂ may be bonded to form a ring.
6).
(B) The positive photosensitive composition as described in any one of 1 to 5 above, wherein the resin as the component further has a repeating unit represented by the following general formula (II).

In general formula (II):
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom, and is the same as Xa ₁ in the general formula (I) .
Rx ₁ to Rx ₃ each independently represents an alkyl group or a cycloalkyl group. Two are bonded in rx ₁ to Rx _3, may form a cycloalkyl group.
7).
1 to 6 above, further comprising a compound that generates an acid upon irradiation with actinic rays or radiation other than the compound of component (A), or two or more compounds of component (A). The positive photosensitive composition as described in any one of these.
8).
The acid which contains two or more compounds of component (A) and each of the two compounds of component (A) is generated by irradiation with actinic rays or radiation has a total number of atoms other than hydrogen atoms of each other. 8. The positive photosensitive composition as described in 7 above, which is two or more different organic acids.
9.
A resist film formed from the positive photosensitive composition according to any one of 1 to 8 above.
10.
10. A pattern forming method comprising a step of exposing and developing the resist film as described in 9 above.
11.
11. The pattern forming method as described in 10 above, wherein the exposure is immersion exposure.
In addition, although this invention has the structure of said 1-11, below, it described for reference also about others.

(1) (A) a compound capable of generating a sulfonic acid having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms by irradiation with actinic rays or radiation; and (B) A positive photosensitive composition comprising a resin having an acid-decomposable repeating unit represented by the following general formula (I) and having an increased dissolution rate in an alkaline developer by the action of an acid.

In general formula (I),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
Ry _{1 to} Ry ₃ each independently represents an alkyl group or a cycloalkyl group. At least two members out of Ry _{1 to} Ry ₃ may be bonded to form a monocyclic or polycyclic hydrocarbon structure.
Z represents a divalent linking group.

  (2) The positive type as described in (1), wherein the compound of component (A) is a compound that generates a sulfonic acid represented by the following general formula (S1) upon irradiation with actinic rays or radiation. Photosensitive composition.

In the general formula (S1),
Rf represents a fluorine-substituted alkylene group having 2 or 3 carbon atoms.
A ₁ represents a divalent linking group having a single bond or a hetero atom.
B ₁ represents a hydrogen atom, a fluorine atom, a monovalent organic group having a hydrocarbon structure, a sulfonic acid group, a carboxyl group, a hydroxyl group or a cyano group.

  (3) The compound of (A) component is a compound that generates perfluoroalkanesulfonic acid having 2 or 3 carbon atoms upon irradiation with actinic rays or radiation, (1) or (2) Positive photosensitive composition.

  (4) The resin of component (B) further has a repeating unit having at least one kind selected from a lactone group, a hydroxyl group, a cyano group and an alkali-soluble group, and any one of (1) to (3) A positive photosensitive composition according to claim 1.

  (5) In the general formula (I), Z is a divalent chain hydrocarbon group or a divalent cyclic hydrocarbon group, according to any one of (1) to (4), A positive photosensitive composition.

  (6) A pattern formation comprising a step of forming a photosensitive film from the positive photosensitive composition according to any one of (1) to (5), and exposing and developing the photosensitive film. Method.

  The preferred embodiments of the present invention will be further described below.

  (7) The compound of component (A) is a compound that generates a sulfonic acid having a total carbon number of 4 or more upon irradiation with actinic rays or radiation, according to any one of (1) to (5), A positive photosensitive composition.

  (8) A mixed solvent containing at least two kinds selected from a solvent having a hydroxyl group, a solvent having an ester structure, a solvent having a ketone structure, a solvent having a lactone structure, and a solvent having a carbonate structure. The positive photosensitive composition according to any one of (1) to (5) and (7).

  INDUSTRIAL APPLICABILITY According to the present invention, there is provided a positive photosensitive composition that forms a good profile pattern with improved pattern collapse and line edge roughness performance even in the formation of a fine pattern of 100 nm or less, and a pattern forming method using the same. can do.

Hereinafter, the best mode for carrying out the present invention will be described.
In addition, in the description of the group (atomic group) in this specification, the description which does not describe substitution and non-substitution includes what does not have a substituent and what has a substituent. . For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

[1] A compound that generates a sulfonic acid having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms upon irradiation with actinic rays or radiation. The composition is a compound that generates a sulfonic acid having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms upon irradiation with actinic rays or radiation (“(A) component” Also referred to as “compounds of”. Here, the fluoroalkyl chain having 2 or 3 carbon atoms refers to a fluoroalkyl chain in which carbon atoms substituted with fluorine atoms are continuously 2 or 3 bonded. Further, the fluoroalkyl chain having 4 or more carbon atoms refers to a fluoroalkyl chain in which four or more carbon atoms substituted with fluorine atoms are continuously bonded.

The sulfonic acid having 2 or 3 carbon fluoroalkyl chains and not having a fluoroalkyl chain having 4 or more carbon atoms generated by irradiation with actinic rays or radiation is a sulfonic acid having 2 to 30 carbon atoms in total. More preferably, the total carbon number is 3 to 25, and still more preferably 6 to 20.

  The compound of component (A) is preferably a compound that generates a sulfonic acid represented by the following general formula (S1) upon irradiation with actinic rays or radiation.

In the general formula (S1),
Rf represents a fluorine-substituted alkylene group having 2 or 3 carbon atoms.
A ₁ represents a divalent linking group having a single bond or a hetero atom.
B ₁ represents a hydrogen atom, a fluorine atom, a monovalent organic group having a hydrocarbon structure, a sulfonic acid group, a carboxyl group, a hydroxyl group or a cyano group.

In the general formula (S1), the fluorine-substituted alkylene group having 2 or 3 carbon atoms in Rf is preferably —CF ₂ CF ₂ —, —CF (CF ₃ ) —, — (CF ₂ ). ₃ —, —C (CF ₃ ) ₂ —, —CF (CF ₃ ) CF ₂ —, and —CF ₂ CF (CF ₃ ) —.
The divalent linking group having a hetero atom in A ₁ is preferably —C (═O) O—, —C (═O) —, —SO ₂ —, —SO ₃ —, —SO ₂ N (A ₂ ) — (wherein A ₂ is a hydrogen atom, an alkyl group which may be substituted), —O—, —S—, and the like, and two or more of these may be combined. Good. When two or more are combined, it is preferably via a linking group having no hetero atom such as an alkylene group or an arylene group.
The monovalent organic group having a hydrocarbon structure in B ₁ is preferably an alkyl group, an aryl group or an aralkyl group having 1 to 20 carbon atoms, and may further have a substituent.
Examples of the alkyl group in B ₁ include a chain, branched, monocyclic or polycyclic alkyl group, or an alkyl group in which these are combined, and more preferably has 4 to 15 carbon atoms. The line edge roughness performance is improved by adjusting the alkyl chain length. The alkyl chain may have a divalent linking group having a hetero atom, and preferred divalent linking groups include the divalent linking groups mentioned for A ₁ .
Examples of the aryl group in B ₁ include a phenyl group and a naphthyl group.
Examples of the aralkyl group in B ₁ include a combination of the above alkyl group and aryl group.
B ₁ and Rf or B ₁ and A ₁ or B ₁ and A ₂ may combine to form a ring structure. The formed ring is a 3- to 8-membered ring, preferably a 5-membered ring or a 6-membered ring.

  As the sulfonic acid having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms, a sulfonic acid represented by the following general formula is preferable.

  Specific examples of preferred sulfonic acids having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms are shown below, but the present invention is not limited thereto. Absent.

  Examples of compounds that generate a sulfonic acid having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms upon irradiation with actinic rays or radiation include, for example, diazonium salts and phosphonium salts. , Sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, and o-nitrobenzyl sulfonates.

  In addition, by irradiation with these actinic rays or radiation, a group or compound that generates a sulfonic acid having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms is converted into a polymer. Compounds introduced into the main chain or side chain, for example, U.S. Pat. No. 3,849,137, German Patent No. 3914407, JP-A-63-26653, JP-A-55-164824, JP-A-62- 69263, JP-A 63-146038, JP-A 63-163452, JP-A 62-153853, JP-A 63-146029, and the like can be used.

Furthermore, it has a fluoroalkyl chain having 2 or 3 carbon atoms and a fluoroalkyl chain having 4 or more carbon atoms by the light described in US Pat. No. 3,779,778 and European Patent 126,712. Compounds that generate no sulfonic acid can also be used.

  As a preferable compound among the compounds that generate a sulfonic acid having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms by irradiation with actinic rays or radiation, the following general formula Examples thereof include compounds represented by (ZIa) and (ZIIa).

In general formula (ZIa):
R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
Xd- represents an anion of a sulfonic acid having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms.

Specific examples of the organic group as R ₂₀₁ , R ₂₀₂ and R _{203 in the} general formula (ZIa) correspond to those in the compounds (ZI-1a), (ZI-2a) and (ZI-3a) described later. The group can be mentioned.

Two members out of R _{201 to} R ₂₀₃ may combine to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).

In addition, the compound which has two or more structures represented by general formula (ZIa) may be sufficient. For example, at least one of R ₂₀₁ to R ₂₀₃ of the compound represented by the general formula (ZIa) is, at least one bond with structure of R ₂₀₁ to R ₂₀₃ in formula (ZIa) another compound represented by It may be a compound.

  More preferred (ZIa) components include compounds (ZI-1a), (ZI-2a), and (ZI-3a) described below.

Compound (ZI-1a) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (ZIa), arylsulfonium compound, i.e., a compound having arylsulfonium as a cation.
In the arylsulfonium compound, all of R _{201 to} R ₂₀₃ may be an aryl group, or a part of R _{201 to} R ₂₀₃ may be an aryl group, and the rest may be an alkyl group or a cycloalkyl group.
Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, aryldialkylsulfonium compounds, diarylcycloalkylsulfonium compounds, and aryldicycloalkylsulfonium compounds.
The aryl group of the arylsulfonium compound is preferably an aryl group such as a phenyl group or a naphthyl group, or a heteroaryl group such as an indole residue or a pyrrole residue, more preferably a phenyl group or an indole residue. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.
The alkyl group that the arylsulfonium compound has as necessary is preferably a linear or branched alkyl group having 1 to 15 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, sec- Examples thereof include a butyl group and a t-butyl group.
The cycloalkyl group that the arylsulfonium compound has as necessary is preferably a cycloalkyl group having 3 to 15 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.
The aryl group, alkyl group, and cycloalkyl group of R _{201 to} R ₂₀₃ are an alkyl group (for example, having 1 to 15 carbon atoms), a cycloalkyl group (for example, having 3 to 15 carbon atoms), an aryl group (for example, having 6 to 14 carbon atoms). ), An alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio group as a substituent. Preferred substituents are straight chain, branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, straight chain, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, and most preferably They are a C1-C4 alkyl group and a C1-C4 alkoxy group. The substituent may be substituted with any one of the three R _{201 to} R ₂₀₃ , or may be substituted with all three. When R _{201 to} R ₂₀₃ are an aryl group, the substituent is preferably substituted at the p-position of the aryl group.
The arylsulfonium cation is preferably a triphenylsulfonium cation which may be substituted, a naphthyltetrahydrothiophenium cation which may be substituted, or a phenyltetrahydrothiophenium cation which may be substituted.

Next, the compound (ZI-2a) will be described.
The compound (ZI-2a) is a compound in the case where R _{201 to} R ₂₀₃ in the general formula (ZIa) each independently represents an organic group not containing an aromatic ring. Here, the aromatic ring includes an aromatic ring having a hetero atom.
The organic group having no aromatic ring as R ₂₀₁ to R ₂₀₃ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.
R _{201 to} R ₂₀₃ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear, branched, cyclic 2-oxoalkyl group, or an alkoxycarbonylmethyl group, particularly preferably Is a linear, branched 2-oxoalkyl group.

The alkyl group as R ₂₀₁ to R ₂₀₃ may be either straight-chain, branched, preferably a straight-chain or branched alkyl group (e.g., methyl group, an ethyl group having 1 to 10 carbon atoms, a propyl group Butyl group, pentyl group). The alkyl group as R ₂₀₁ to R ₂₀₃ may be linear, branched 2-oxoalkyl group, more preferably an alkoxycarbonylmethyl group.
The cycloalkyl group as R ₂₀₁ to R ₂₀₃ is preferably, and a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, norbornyl). The cycloalkyl group as R ₂₀₁ to R ₂₀₃ is more preferably a cyclic 2-oxoalkyl group.
The linear, branched or cyclic 2-oxoalkyl group in R _{201 to} R ₂₀₃ is preferably a group having> C═O at the 2-position of the above alkyl group or cycloalkyl group.
The alkoxy group in the alkoxycarbonylmethyl group as R ₂₀₁ to R _203, preferably may be mentioned alkoxy groups having 1 to 5 carbon atoms (a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group).
R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

  The compound (ZI-3a) is a compound represented by the following general formula (ZI-3a), and is a compound having a phenacylsulfonium salt structure.

In the general formula (ZI-3a),
R _{1c to} R _5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, or a halogen atom.
R _6c and R _7c each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group.
Rx and Ry each independently represents an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group.
Any two or more of R _{1c to} R _5c , and R _x and R _y may be bonded to each other to form a ring structure, and this ring structure includes an oxygen atom, a sulfur atom, an ester bond, and an amide bond. May be included. Examples of the group formed by combining any two or more of R _{1c to} R _5c and R _x and R _y include a butylene group and a pentylene group.
Xd− represents a sulfonic acid anion having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms, and is the same as Xd− in the general formula (ZIa) belongs to.

The alkyl group as R _{1c to} R _7c may be either linear or branched, for example, an alkyl group having 1 to 20 carbon atoms, preferably a linear or branched alkyl group having 1 to 12 carbon atoms. Examples thereof include a group (for example, methyl group, ethyl group, linear or branched propyl group, linear or branched butyl group, linear or branched pentyl group).
Examples of the cycloalkyl group as R _{1c to} R _7c include a cycloalkyl group having 3 to 20 carbon atoms, preferably a cycloalkyl group having 3 to 8 carbon atoms (for example, a cyclopentyl group and a cyclohexyl group). Can do.
The alkoxy group as R _{1c to} R _{5c may} be linear, branched or cyclic, for example, an alkoxy group having 1 to 10 carbon atoms, preferably a linear or branched alkoxy group having 1 to 5 carbon atoms. (For example, methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group), C3-C8 cyclic alkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group) ).
Preferably, any one of R _{1c to} R _5c is a linear or branched alkyl group, a cycloalkyl group, or a linear, branched or cyclic alkoxy group, and more preferably the sum of the carbon number of R _1c to R _5c is 2 ~ 15. Thereby, solvent solubility improves more and generation | occurrence | production of a particle is suppressed at the time of a preservation | save.

_Examples of the alkyl group as R _x and R _y include the same alkyl groups as R _{1c to} R _7c . The alkyl group as R _x and R _y is more preferably a linear or branched 2-oxoalkyl group or an alkoxycarbonylmethyl group.
The cycloalkyl group as R _x and R _y may be the same as the cycloalkyl group as R _1c to R _7c. The cycloalkyl group as R _x and R _y is more preferably a cyclic 2-oxoalkyl group.
Examples of the linear, branched and cyclic 2-oxoalkyl group include a group having> C═O at the 2-position of the alkyl group or cycloalkyl group as R _{1c to} R _7c .
Examples of the alkoxy group in the alkoxycarbonylmethyl group include the same alkoxy groups as R _{1c to} R _5c .
R _x and R _y are preferably an alkyl group having 4 or more carbon atoms, more preferably 6 or more, and still more preferably 8 or more.

In the general formula (ZIIa),
R ₂₀₄ to R ₂₀₅ each independently represents an aryl group, an alkyl group or a cycloalkyl group.
The aryl group of R ₂₀₄ to R _205, a phenyl group, a naphthyl group, more preferably a phenyl group.
The alkyl group as R ₂₀₄ to R ₂₀₅ may be either straight-chain, branched, preferably a straight-chain or branched alkyl group (e.g., methyl group, an ethyl group having 1 to 10 carbon atoms, a propyl group Butyl group, pentyl group).
The cycloalkyl group as R ₂₀₄ to R ₂₀₅ is preferably, and a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, norbornyl).
The R ₂₀₄ to R ₂₀₇ are substituents which may have, for example, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (e.g., 6 carbon atoms 15), alkoxy groups (for example, having 1 to 15 carbon atoms), halogen atoms, hydroxyl groups, phenylthio groups and the like.

  As preferred compounds among the compounds that generate a sulfonic acid having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms upon irradiation with actinic rays or radiation, The compound represented by general formula (ZIIIa) and (ZIVa) can be mentioned.

In general formulas (ZIIIa) and (ZIVa),
Xd represents a monovalent group formed by removing a hydrogen atom from a sulfonic acid having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms.
R ₂₀₇ and R ₂₀₈ each independently represents an alkyl group, a cycloalkyl group, an aryl group, or an electron-withdrawing group. R ₂₀₇ is preferably an aryl group. R ₂₀₈ is preferably an electron-withdrawing group, more preferably a cyano group or a fluoroalkyl group.
A represents an alkylene group, an alkenylene group or an arylene group.

Among the compounds that generate a sulfonic acid having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms by irradiation with actinic rays or radiation, more preferably, the compound represented by the general formula ( ZIa) to (ZIIIa), more preferably (Z
Ia), and particularly preferred are compounds represented by (ZI-1a) to (ZI-3a).

  Among the compounds that generate a sulfonic acid having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms upon irradiation with actinic rays or radiation, preferred examples are as follows. I will give you.

  (A) The compound of a component can be used individually by 1 type or in combination of 2 or more types. When two or more types are used in combination, it is preferable to combine two types of compounds that generate two types of organic acids that differ in the total number of atoms excluding hydrogen atoms by two or more.

  The content of the component (A) compound in the composition is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass, still more preferably 3 to 8%, based on the total solid content of the resist composition. % By mass, particularly preferably 4 to 7% by mass.

In the present invention, a compound capable of generating an acid upon irradiation with actinic rays or radiation (hereinafter also referred to as a “combination acid generator”) other than the compound of component (A) together with the compound of component (A). May be used.

  Examples of the compound capable of generating an acid upon irradiation with actinic rays or radiation that can be used together with the component (A) compound include compounds represented by the following general formulas (ZI), (ZII), and (ZIII). .

In general formula (ZI):
R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
X ⁻ represents a non-nucleophilic anion, preferably sulfonate anion, carboxylate anion, bis (alkylsulfonyl) amide anion, tris (alkylsulfonyl) methide anion, BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ^{− and the} like. Preferably, it is an organic anion containing a carbon atom.

  Preferred organic anions include organic anions represented by the following general formulas (AN1) to (AN4).

In general formulas (AN1) to (AN2),
Rc ₁ represents an organic group.
Examples of the organic group for Rc ₁ include those having 1 to 30 carbon atoms, and preferably an alkyl group, an aryl group, or a plurality thereof, which may be substituted, is a single bond, —O—, —CO ₂ —. , —S—, —SO ₃ —, —SO ₂ N (Rd ₁ ) — and the like. Rd ₁ represents a hydrogen atom or an alkyl group, and may form a ring structure with the bonded alkyl group or aryl group.
The organic group of Rc ₁ is more preferably an alkyl group substituted at the 1-position with a fluorine atom or a fluoroalkyl group, or a phenyl group substituted with a fluorine atom or a fluoroalkyl group. By having a fluorine atom or a fluoroalkyl group, the acidity of the acid generated by light irradiation is increased and the sensitivity is improved. When Rc ₁ has 5 or more carbon atoms, it is preferable that at least one carbon atom has a hydrogen atom, not all hydrogen atoms are substituted with fluorine atoms, and the number of hydrogen atoms is fluorine. More preferably than atoms. By not having a perfluoroalkyl group having 5 or more carbon atoms, ecotoxicity is reduced.

As a particularly preferred embodiment of Rc ₁ , groups represented by the following general formula can be exemplified.

In the above general formula,
Rc ₆ represents a perfluoroalkylene group, preferably, 3 to 5 fluorine atoms and / or 1-3 phenylene group substituted with a fluoroalkyl group.
Ax represents a linking group (preferably a single bond, —O—, —CO ₂ —, —S—, —SO ₃ —, —SO ₂ N (Rd ₁ ) —). Rd ₁ represents a hydrogen atom or an alkyl group, and may combine with Rc ₇ to form a ring structure.
Rc ₇ represents a hydrogen atom, a fluorine atom, a linear or branched alkyl group, a monocyclic or polycyclic cycloalkyl group or an aryl group. The alkyl group, cycloalkyl group and aryl group may be substituted, but preferably have no fluorine atom as a substituent.

  However, an anion of a sulfonic acid having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms is not included in AN1.

R _{201 to} R ₂₀₃ in the compounds (ZI-1) to (ZI-3) have the same meanings as those in the compounds (ZI-1a) to (ZI-3a).

In the general formulas (AN3) to (AN4),
Rc ₃ , Rc ₄ and Rc ₅ each independently represents an organic group.
Preferred examples of the organic group for Rc ₃ , Rc ₄ and Rc ₅ include the same organic groups as those for Rc ₁ .
Rc ₃ and Rc ₄ may combine to form a ring. Examples of the group formed by combining Rc ₃ and Rc ₄ include an alkylene group and an arylene group. Preferably, it is a C2-C4 perfluoroalkylene group. By combining Rc ₃ and Rc ₄ to form a ring, the acidity of the acid generated by light irradiation is increased, and the sensitivity is improved, which is preferable.

In the general formula (ZI),
The carbon number of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is generally 1-30, preferably 1-20.
Two of R _{201 to} R ₂₀₃ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).
Specific examples of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include a compound (ZI-1) described later.
), (ZI-2) and (ZI-3).

In addition, the compound which has two or more structures represented by general formula (ZI) may be sufficient. For example, the general formula at least one of R ₂₀₁ to R ₂₀₃ of a compound represented by (ZI) is, at least one bond with structure of R ₂₀₁ to R ₂₀₃ of another compound represented by formula (ZI) It may be a compound.

  More preferable (ZI) components include compounds (ZI-1), (ZI-2), and (ZI-3) described below.

The compound (ZI-1) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (ZI), arylsulfonium compound, i.e., a compound having arylsulfonium as a cation.

Compound (ZI-2) is a compound in the case where R _{201 to} R ₂₀₃ in formula (ZI) each independently represents an organic group not containing an aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.

  The compound (ZI-3) is a compound represented by the following general formula (ZI-3), and is a compound having a phenacylsulfonium salt structure.

In general formula (ZI-3),
R _{1c to} R _5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group or a halogen atom.
R _6c and R _7c each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group.
Rx and Ry each independently represents an alkyl group, a cycloalkyl group, an allyl group or a vinyl group.
Any two or more of R _1c to R _7c, and R _x and R _y may be bonded to each other to form a ring structure, the ring structure may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond May be included. Examples of the group formed by combining any two or more of R _{1c to} R _7c and R _x and R _y include a butylene group and a pentylene group.
X ⁻ represents a non-nucleophilic anion, and examples thereof include those similar to the non-nucleophilic anion of X ⁻ in formula (I).

R _{201 to} R ₂₀₃ in the compounds (ZI-1) to (ZI-3) have the same meanings as those in the compounds (ZI-1a) to (ZI-3a).

In the general formulas (ZII) and (ZIII),
R ₂₀₄ to R ₂₀₇ each independently represents an aryl group, an alkyl group or a cycloalkyl group.
The aryl group of R ₂₀₄ to R _207, a phenyl group, a naphthyl group, more preferably a phenyl group.
The alkyl group as R ₂₀₄ to R ₂₀₇ may preferably be mentioned a linear or branched alkyl group having 1 to 10 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group).
The cycloalkyl group as R ₂₀₄ to R ₂₀₇ is preferably, and a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, norbornyl).
R ₂₀₄ to R ₂₀₇ may have a substituent. The R ₂₀₄ to R ₂₀₇ are substituents which may have, for example, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (e.g., 6 carbon atoms 15), alkoxy groups (for example, having 1 to 15 carbon atoms), halogen atoms, hydroxyl groups, phenylthio groups and the like.
X ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of X ^{− in} formula (I).

  Among the compounds that decompose upon irradiation with actinic rays or radiation to generate acids, compounds represented by the following general formulas (ZIV), (ZV), and (ZVI) can be further exemplified.

In the general formulas (ZIV) to (ZVI),
Ar ₃ and Ar ₄ each independently represents an aryl group.
R ₂₀₆ represents an alkyl group, a cycloalkyl group or an aryl group.
R ₂₀₇ and R ₂₀₈ each independently represents an alkyl group, a cycloalkyl group, an aryl group, or an electron-withdrawing group. R ₂₀₇ is preferably an aryl group. R ₂₀₈ is preferably an electron-withdrawing group, more preferably a cyano group or a fluoroalkyl group.
A represents an alkylene group, an alkenylene group or an arylene group.

  Of the compounds that generate an acid upon irradiation with actinic rays or radiation, more preferred are compounds represented by general formulas (ZI) to (ZIII), and even more preferred are compounds represented by general formula (ZI). And particularly preferred are compounds represented by the general formulas (ZI-1) to (ZI-3).

  Furthermore, the compound which generate | occur | produces the acid represented by the following general formula (AC1)-(AC3) by irradiation of actinic light or a radiation is preferable.

In formula (AC1) ~ (AC3), Rc 1, Rc 3 ~Rc 5 are in the general formula (AN1) ~ (AN4), and Rc _1, Rc ₃ ~Rc ₅ synonymous.

A particularly preferred embodiment of the acid generator is a compound in which, in the structure of the general formula (ZI), X ⁻ is an anion selected from the above (AN1), (AN3), and (AN4).

  Among the compounds that generate an acid upon irradiation with actinic rays or radiation, examples of particularly preferable compounds are listed below, but the present invention is not limited thereto.

  The content of the combined acid generator in the composition is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass, further preferably 3 to 8% by mass, based on the total solid content of the resist composition. Most preferably, it is 4-7 mass%.

[2] Resin whose dissolution rate in an alkaline developer is increased by the action of an acid The resin whose dissolution rate in an alkaline developer is increased by the action of an acid used in the positive photosensitive composition of the present invention is as follows. A resin having an acid-decomposable repeating unit represented by formula (I) (also referred to as “resin of component (B)”).

In general formula (I),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
Ry _{1 to} Ry ₃ each independently represents an alkyl group or a cycloalkyl group. At least two members out of Ry _{1 to} Ry ₃ may be bonded to form a monocyclic or polycyclic hydrocarbon structure.
Z represents a divalent linking group.

In general formula (I), the alkyl group of Xa ₁ may be substituted with a hydroxyl group, a halogen atom, or the like.
Xa ₁ is preferably a hydrogen atom or a methyl group.
The alkyl group of Ry _{1 to} Ry ₃ may be either a linear alkyl group or a branched alkyl group, and may have a substituent. Preferred linear and branched alkyl groups have 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms, and include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and t-butyl groups. And preferably a methyl group or an ethyl group.
The cycloalkyl group of Ry ₁ to Ry _3, for example, a monocyclic cycloalkyl group having 3 to 8 carbon atoms may be a cycloalkyl group polycyclic 7-14 carbon atoms, optionally substituted Also good. Preferred examples of the monocyclic cycloalkyl group include a cyclopentyl group, a cyclohexyl group, and a cyclopropyl group. Preferred examples of the polycyclic cycloalkyl group include an adamantyl group, a norbornane group, a tetracyclododecanyl group, a tricyclodecanyl group, and a diamantyl group.
As the monocyclic hydrocarbon structure formed by combining at least two members out of Ry _{1 to} Ry ₃ , a cyclopentyl group and a cyclohexyl group are preferable. As the polycyclic hydrocarbon structure formed by bonding at least two of Ry _{1 to} Ry ₃ , an adamantyl group, a norbornyl group, and a tetracyclododecanyl group are preferable.
Z is preferably a divalent linking group having 1 to 20 carbon atoms, more preferably a chain alkylene group having 1 to 4 carbon atoms, a cyclic alkylene group having 5 to 20 carbon atoms, or a combination thereof.
Examples of the chain alkylene group having 1 to 4 carbon atoms include a methylene group, an ethylene group, a propylene group, and a butylene group, which may be linear or branched. A methylene group is preferred.
Examples of the cyclic alkylene group having 5 to 20 carbon atoms include monocyclic cyclic alkylene groups such as cyclopentylene group and cyclohexylene group, and polycyclic cyclic alkylene groups such as norbornylene group and adamantylene group. An adamantylene group is preferred.

The polymerizable compound for forming the repeating unit represented by the general formula (I) can be easily synthesized by a known method. For example, using a method similar to the method described in JP-A-2005-331918, as shown in the following formula, an alcohol and a carboxylic acid halide compound are reacted under basic conditions, and then this and a carboxylic acid compound are converted into a base. It can be synthesized by reacting under sexual conditions.

  Preferred specific examples of the repeating unit represented by formula (I) are shown below, but the present invention is not limited thereto.

  The repeating unit represented by the general formula (I) is decomposed by the action of an acid to generate a carboxyl group, and the dissolution rate in an alkaline developer increases.

In addition to the acid-decomposable repeating unit represented by formula (I), the resin of component (B) may further have another acid-decomposable repeating unit.
Other acid-decomposable repeating units other than the acid-decomposable repeating unit represented by the general formula (I) are preferably repeating units represented by the following general formula (II).

In general formula (II):
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom, and is the same as Xa ₁ in the general formula (I).
Rx _{1 to} Rx ₃ each independently represents an alkyl group or a cycloalkyl group. Two of Rx _{1 to} Rx ₃ may combine to form a cycloalkyl group.

The alkyl group of Rx _{1 to} Rx ₃ is linear or branched having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and t-butyl group. The shape is preferred.
Examples of the cycloalkyl group represented by Rx _{1 to} Rx ₃ include monocyclic cycloalkyl groups such as cyclopentyl group and cyclohexyl group, polycyclic cycloalkyl groups such as norbornyl group, tetracyclodecanyl group, tetracyclododecanyl group, and adamantyl group. Groups are preferred.
The cycloalkyl group formed by bonding at least two of Rx _{1 to} Rx ₃ includes a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, a norbornyl group, a tetracyclodecanyl group, and a tetracyclododecanyl group. And a polycyclic cycloalkyl group such as an adamantyl group is preferred.
It is preferable that Rx ₁ is a methyl group or an ethyl group, and Rx ₂ and Rx ₃ are bonded to each other to bond the above monocyclic or polycyclic cycloalkyl group.

  Although the specific example of the repeating unit which has a preferable acid-decomposable group is shown below, this invention is not limited to this.

  Preferred repeating units represented by the general formula (II) are 1, 2, 10, 11, 12, 13, and 14 repeating units in the above specific examples.

  When the repeating unit having an acid-decomposable group represented by the general formula (I) and a repeating unit having another acid-decomposable group (preferably a repeating unit represented by the general formula (II)) are used in combination, The ratio of the repeating unit having an acid-decomposable group represented by the general formula (I) and the repeating unit having another acid-decomposable group is 90:10 to 10:90, more preferably 80 in terms of molar ratio. : 20 to 20:80.

  The content of repeating units having all acid-decomposable groups in the resin of component (B) is preferably 20 to 50 mol%, more preferably 25 to 45 mol%, based on all repeating units in the polymer.

  The resin as the component (B) preferably further has a repeating unit having at least one group selected from a lactone group, a hydroxyl group, a cyano group, and an alkali-soluble group.

The resin of component (B) preferably has a repeating unit having a lactone structure.
Any lactone structure can be used as long as it has a lactone structure, but a 5- to 7-membered lactone structure is preferable, and a bicyclo structure or a spiro structure is formed in the 5- to 7-membered ring lactone structure. The other ring structure is preferably condensed. It is more preferable to have a repeating unit having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16). The lactone structure may be directly bonded to the main chain. Preferred lactone structures are (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), (LC1-14), and a specific lactone structure is used. This improves line edge roughness and development defects.

The lactone structure moiety may or may not have a substituent (Rb ₂ ). Preferred substituents (Rb ₂ ) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, and a carboxyl group. , Halogen atom, hydroxyl group, cyano group, acid-decomposable group and the like. More preferably, they are a C1-C4 alkyl group, a cyano group, and an acid-decomposable group. n ₂ represents an integer of 0-4. When n ₂ is 2 or more, a plurality of Rb ₂ may be the same or different, and a plurality of Rb ₂ may be bonded to form a ring.

  Examples of the repeating unit having a lactone structure represented by any one of the general formulas (LC1-1) to (LC1-16) include a repeating unit represented by the following general formula (AI).

In general formula (AI),
R _b0 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms. Preferable substituents that the alkyl group for R _b0 may have include a hydroxyl group and a halogen atom. Examples of the halogen atom for R _b0 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R _b0 is preferably a hydrogen atom or a methyl group.
A _b is a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, a carboxyl group, or a divalent linking that is a combination thereof. Represents a group. Preferably a single bond, -Ab ₁ -CO ₂ - is a divalent linking group represented by. Ab ₁ is a linear, branched alkylene group, monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexyl group, an adamantyl group, or a norbornyl group.
V represents a group having a structure represented by any one of the general formulas (LC1-1) to (LC1-16).

  The repeating unit having a lactone structure usually has an optical isomer, but any optical isomer may be used. One optical isomer may be used alone, or a plurality of optical isomers may be mixed and used. When one kind of optical isomer is mainly used, the optical purity (ee) thereof is preferably 90 or more, more preferably 95 or more.

  The content of the repeating unit having a lactone structure is preferably from 15 to 60 mol%, more preferably from 20 to 50 mol%, still more preferably from 30 to 50 mol%, based on all repeating units in the polymer.

  Specific examples of the repeating unit having a lactone structure are given below, but the present invention is not limited thereto.

  Particularly preferred repeating units having a lactone structure include the following repeating units. By selecting the optimum lactone structure, the pattern profile and the density dependence become good.

  The resin as the component (B) preferably has a repeating unit having a hydroxyl group or a cyano group. This improves the substrate adhesion and developer compatibility. The repeating unit having a hydroxyl group or a cyano group is preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group. The alicyclic hydrocarbon structure in the alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably an adamantyl group, a diamantyl group, or a norbornane group. As the alicyclic hydrocarbon structure substituted with a preferred hydroxyl group or cyano group, partial structures represented by the following general formulas (VIIa) to (VIId) are preferred.

In general formulas (VIIa) to (VIIc),
R ₂ c to R ₄ c each independently represents a hydrogen atom, a hydroxyl group or a cyano group. However, at least one of R ₂ c to R ₄ c represents a hydroxyl group or a cyano group. Preferably, one or two of R ₂ c to R ₄ c are a hydroxyl group and the remaining is a hydrogen atom. In general formula (VIIa), more preferably, _two of R ₂ c to R ₄ c are hydroxyl groups and the remaining are hydrogen atoms.

  Examples of the repeating unit having a partial structure represented by the general formulas (VIIa) to (VIId) include the repeating units represented by the following general formulas (AIIa) to (AIId).

In the general formulas (AIIa) to (AIIb),
R ₁ c represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.
R ₂ c to R ₄ c are in the general formula (VIIa) ~ (VIIc), same meanings as R ₂ c~R ₄ c.

  The content of the repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably 5 to 40 mol%, more preferably 5 to 30 mol%, still more preferably 10 with respect to all repeating units in the polymer. ˜25 mol%.

  Specific examples of the repeating unit having a hydroxyl group or a cyano group are given below, but the present invention is not limited thereto.

The resin of component (B) preferably has a repeating unit having an alkali-soluble group. Examples of the alkali-soluble group include a carboxyl group, a sulfonamide group, a sulfonylimide group, a bisulsulfonylimide group, and an aliphatic alcohol (for example, hexafluoroisopropanol group) substituted with an electron-attracting group at the α-position. It is more preferable to have a repeating unit. By containing the repeating unit having an alkali-soluble group, the resolution in contact hole applications is increased. The repeating unit having an alkali-soluble group includes a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or an alkali in the main chain of the resin through a linking group. Either a repeating unit to which a soluble group is bonded, or a polymerization initiator or chain transfer agent having an alkali-soluble group is used at the time of polymerization and introduced at the end of the polymer chain, and the linking group is monocyclic or polycyclic. It may have a cyclic hydrocarbon structure. Particularly preferred are repeating units of acrylic acid or methacrylic acid.

  As for content of the repeating unit which has an alkali-soluble group, 1-20 mol% is preferable with respect to all the repeating units in a polymer, More preferably, it is 3-15 mol%, More preferably, it is 5-10 mol%.

  Specific examples of the repeating unit having an alkali-soluble group are shown below, but the present invention is not limited thereto.

  As the repeating unit having at least one group selected from a lactone group, a hydroxyl group, a cyano group and an alkali-soluble group, more preferably, a repeating unit having at least two groups selected from a lactone group, a hydroxyl group, a cyano group and an alkali-soluble group Preferably, it is a repeating unit having a cyano group and a lactone group. Particularly preferred is a repeating unit having a structure in which a cyano group is substituted on the lactone structure of LCI-4.

The resin of component (B) may further contain a repeating unit that has an alicyclic hydrocarbon structure and does not exhibit acid decomposability. This can reduce the elution of low molecular components from the resist film to the immersion liquid during immersion exposure. Examples of such a repeating unit include 1-adamantyl (meth) acrylate, diamantyl (meth) acrylate, tricyclodecanyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like.

  In addition to the above repeating structural unit, the resin of component (B) is dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general required properties of resist, such as resolution, heat resistance, and sensitivity. Various repeating structural units can be included for the purpose of adjusting the above.

  Examples of such repeating structural units include, but are not limited to, repeating structural units corresponding to the following monomers.

Thereby, the performance required for the resin of the component (B), in particular,
(1) Solubility in coating solvent,
(2) Film formability (glass transition point),
(3) Alkali developability,
(4) Membrane slip (hydrophobic, alkali-soluble group selection),
(5) Adhesion of unexposed part to substrate,
(6) Dry etching resistance,
Etc. can be finely adjusted.

  As such a monomer, for example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. Etc.

  In addition, any addition-polymerizable unsaturated compound that can be copolymerized with monomers corresponding to the above various repeating structural units may be copolymerized.

  In the component (B) resin, the molar ratio of each repeating structural unit is the resist dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general resist performance required for resolving power and heat resistance. In order to adjust the sensitivity and the like, it is set as appropriate.

  When the positive photosensitive composition of the present invention is used for ArF exposure, the resin of component (B) preferably has no aromatic group from the viewpoint of transparency to ArF light.

  As the resin of component (B), preferably, all of the repeating units are composed of (meth) acrylate-based repeating units. In this case, all of the repeating units are methacrylate repeating units, all of the repeating units are acrylate repeating units, or all of the repeating units are methacrylate repeating units and acrylate repeating units. Although it can be used, the acrylate-based repeating unit is preferably 50 mol% or less of the total repeating units. More preferably, the (meth) acrylate repeating unit having an acid-decomposable group represented by the general formula (I) is 20 to 50 mol%, the (meth) acrylate repeating unit having a lactone structure is 20 to 50 mol%, It is a copolymer having 5 to 30 mol% of (meth) acrylate-based repeating units having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group, and further containing 0 to 20 mol% of other (meth) acrylate-based repeating units. .

The resin of component (B) can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and the polymerization is performed by heating, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, the polymerization is performed using the same solvent as the solvent used in the positive photosensitive composition of the present invention. Thereby, generation | occurrence | production of the particle at the time of a preservation | save can be suppressed.
The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. If desired, an initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery. The concentration of the reaction is 5 to 50% by mass, preferably 10 to 30% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.
The weight average molecular weight of the resin of component (B) is preferably 1,000 to 200,000, more preferably 3,000 to 20,000, and most preferably 5,000 to as a polystyrene equivalent value by GPC method. 15,000. By setting the weight average molecular weight to 1,000 to 200,000, deterioration of heat resistance and dry etching resistance can be prevented, developability is deteriorated, and viscosity is increased, resulting in deterioration of film forming property. Can be prevented.
The degree of dispersion (molecular weight distribution) is usually from 1 to 5, preferably from 1 to 3, more preferably from 1 to 2. The smaller the molecular weight distribution, the better the resolution and the resist shape, and the smoother the side wall of the resist pattern, the better the roughness.

  When the resin of component (B) is used for a positive photosensitive composition that irradiates KrF excimer laser light, electron beam, X-ray, high energy light (EUV, etc.) having a wavelength of 50 nm or less, The resin preferably has a repeating unit of the general formula (I) and further a repeating unit having a hydroxystyrene structure. Examples of the repeating unit having a hydroxystyrene structure include o-, m-, p-hydroxystyrene and / or hydroxystyrene protected with an acid-decomposable group. The hydroxystyrene repeating unit protected with an acid-decomposable group is preferably 1-alkoxyethoxystyrene or t-butylcarbonyloxystyrene. In addition to the repeating unit represented by the general formula (I) and the repeating unit having a hydroxystyrene structure, it may further have a repeating unit represented by the general formula (II).

Specific examples of the resin having a repeating unit having a hydroxystyrene structure and a repeating unit represented by formula (I) used in the present invention are shown below, but the present invention is not limited thereto. In specific examples, Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.

In the positive photosensitive composition of the present invention, the blending amount of the resin as the component (B) in the entire composition is preferably 50 to 99.9% by mass, more preferably 60 to 99.0% by mass in the total solid content. %.
In the present invention, the resin of component (B) may be used alone or in combination.

Dissolution control compound having a molecular weight of 3000 or less having at least one selected from an alkali-soluble group, a hydrophilic group and an acid-decomposable group. The positive photosensitive composition of the present invention comprises an alkali-soluble group, a hydrophilic group and an acid-decomposable group. A dissolution controlling compound having a molecular weight of 3000 or less (hereinafter also referred to as “solubility controlling compound”) having at least one selected from
Examples of the dissolution control compound include a carboxyl group, a sulfonylimide group, a compound having an alkali-soluble group such as a hydroxyl group substituted at the α-position with a fluoroalkyl group, a hydroxyl group, a lactone group, a cyano group, an amide group, a pyrrolidone group, a sulfone group. A compound having a hydrophilic group such as an amide group or a compound having an acid-decomposable group is preferred. The acid-decomposable group is preferably a group in which a carboxyl group or a hydroxyl group is protected with an acid-decomposable protecting group. In order not to lower the permeability of 220 nm or less as the dissolution control compound, it is preferable to use a compound that does not contain an aromatic ring, or to use a compound having an aromatic ring in an amount of 20 wt% or less based on the solid content of the composition.
Preferred dissolution control compounds include carboxylic acid compounds having an alicyclic hydrocarbon structure such as adamantane (di) carboxylic acid, norbornane carboxylic acid, and cholic acid, or compounds obtained by protecting the carboxylic acid with an acid-decomposable protecting group, such as saccharides. A polyol or a compound having its hydroxyl group protected with an acid-decomposable protecting group is preferred.

  The molecular weight of the dissolution controlling compound is 3000 or less, preferably 300 to 3000, and more preferably 500 to 2500.

  The addition amount of the dissolution control compound is preferably 3 to 40% by mass, more preferably 5 to 20% by mass, based on the solid content of the positive photosensitive composition.

  Specific examples of the dissolution control compound are shown below, but the present invention is not limited thereto.

Basic Compound The positive photosensitive composition of the present invention contains a basic compound in order to reduce the change in performance over time from exposure to heating or to control the diffusibility of the acid generated by exposure in the film. Is preferred.

Examples of basic compounds include nitrogen-containing basic compounds and onium salt compounds.
Preferred examples of the structure of the nitrogen-containing basic compound include compounds having partial structures represented by the following general formulas (A) to (E).

In general formula (A),
R ^250, R ²⁵¹ and R ²⁵² are each independently a hydrogen atom, an alkyl having 1 to 20 carbon atoms, a cycloalkyl group or an aryl group having 6 to 20 carbon atoms having 3 to 20 carbon atoms, R ²⁵⁰ and R ²⁵¹ may be bonded to each other to form a ring. These may have a substituent. Examples of the alkyl group and cycloalkyl group having a substituent include an aminoalkyl group having 1 to 20 carbon atoms, an aminocycloalkyl group having 3 to 20 carbon atoms, and 1 carbon atom. A -20 hydroxyalkyl group or a C3-C20 hydroxycycloalkyl group is preferred.
These may contain an oxygen atom, a sulfur atom, or a nitrogen atom in the alkyl chain.
In general formula (E),
R ²⁵³ , R ²⁵⁴ , R ²⁵⁵ and R ²⁵⁶ each independently represent an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms.

  Preferable compounds include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, and piperidine, and may have a substituent. More preferable compounds include compounds having an imidazole structure, a diazabicyclo structure, an onium hydroxide structure, an onium carboxylate structure, a trialkylamine structure, an aniline structure or a pyridine structure, an alkylamine derivative having a hydroxyl group and / or an ether bond, a hydroxyl group and / or Or the aniline derivative which has an ether bond etc. can be mentioned.

  Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, and benzimidazole. Examples of the compound having a diazabicyclo structure include 1,4-diazabicyclo [2,2,2] octane, 1,5-diazabicyclo [4,3,0] non-5-ene, and 1,8-diazabicyclo [5,4. 0] undec-7-ene and the like. Examples of the compound having an onium hydroxide structure include triarylsulfonium hydroxide, phenacylsulfonium hydroxide, sulfonium hydroxide having a 2-oxoalkyl group, specifically, triphenylsulfonium hydroxide, tris (t-butylphenyl) Examples thereof include sulfonium hydroxide, bis (t-butylphenyl) iodonium hydroxide, phenacylthiophenium hydroxide, and 2-oxopropylthiophenium hydroxide. Examples of the compound having an onium carboxylate structure are compounds in which the anion portion of the compound having an onium hydroxide structure is converted to a carboxylate, and examples thereof include acetate, adamantane-1-carboxylate, and perfluoroalkylcarboxylate. it can. Examples of the compound having a trialkylamine structure include tri (n-butyl) amine and tri (n-octyl) amine. Examples of aniline compounds include 2,6-diisopropylaniline and N, N-dimethylaniline. Examples of the alkylamine derivative having a hydroxyl group and / or an ether bond include ethanolamine, diethanolamine, triethanolamine, and tris (methoxyethoxyethyl) amine. Examples of aniline derivatives having a hydroxyl group and / or an ether bond include N, N-bis (hydroxyethyl) aniline.

  These basic compounds are used alone or in combination of two or more. The usage-amount of a basic compound is 0.001-10 mass% normally based on solid content of a positive photosensitive composition, Preferably it is 0.01-5 mass%. In order to obtain a sufficient addition effect, 0.001% by mass or more is preferable, and 10% by mass or less is preferable in terms of sensitivity and developability of the non-exposed area.

Fluorine and / or silicon surfactant The positive photosensitive composition of the present invention further comprises fluorine and / or silicon surfactant (fluorine surfactant, silicon surfactant, fluorine atom and silicon atom It is preferable to contain either one or two or more surfactants containing both.
When the positive photosensitive composition of the present invention contains fluorine and / or a silicon-based surfactant, adhesion and development defects are obtained with good sensitivity and resolution when using an exposure light source of 250 nm or less, particularly 220 nm or less. It is possible to provide a resist pattern with less.

  Examples of these fluorine and / or silicon surfactants include, for example, JP-A No. 62-36663, JP-A No. 61-226746, JP-A No. 61-226745, JP-A No. 62-170950, JP 63-34540 A, JP 7-230165 A, JP 8-62834 A, JP 9-54432 A, JP 9-5988 A, JP 2002-277862 A, US Patent Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511, 5,824,451 Surfactant can be mentioned, The following commercially available surfactant can also be used as it is.

  Examples of commercially available surfactants that can be used include EFTOP EF301 and EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430 and 431 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189, and R08. (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.), etc. Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

  In addition to the known surfactants described above, surfactants are derived from fluoroaliphatic compounds produced by the telomerization method (also referred to as the telomer method) or the oligomerization method (also referred to as the oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.

  As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. It may be block copolymerized. Examples of the poly (oxyalkylene) group include a poly (oxyethylene) group, a poly (oxypropylene) group, a poly (oxybutylene) group, and the like, and a poly (oxyethylene, oxypropylene, and oxyethylene group). A unit having different chain lengths in the same chain length, such as a block link) or poly (block link of oxyethylene and oxypropylene) may be used. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates).

Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxy) (Ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate) copolymer, acrylate (or methacrylate) and (poly (oxyalkylene)) acrylate having C ₈ F ₁₇ groups (or Copolymer of acrylate (or methacrylate), (poly (oxyethylene)) acrylate (or methacrylate), and (poly (oxypropylene)) acrylate (or methacrylate) having a C ₈ F ₁₇ group Coalesce, etc. Can.

  The amount of fluorine and / or silicon-based surfactant used is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, based on the total amount of the positive photosensitive composition (excluding the solvent). %.

Surface Hydrophobic Resin When the resist film made of the positive photosensitive composition of the present invention is exposed through immersion water, a surface hydrophobizing resin can be further added as necessary. Thereby, the receding contact angle on the resist film surface can be improved and the immersion water followability can be improved. As the surface hydrophobizing resin, any resin can be used as long as the receding contact angle of the surface can be improved by addition, but a resin having at least one of fluorine atom and silicon atom is preferable. The addition amount can be adjusted as appropriate so that the receding contact angle of the resist film is 60 ° to 80 °, but preferably 0.1 to 5% by mass.

Solvent The positive photosensitive composition of the present invention is used by dissolving each component in a predetermined solvent.
Examples of solvents that can be used include ethylene dichloride, cyclohexanone, cyclopentanone, 2-heptanone, γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl ether. Acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, toluene, ethyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N, N- Examples include organic solvents such as dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and tetrahydrofuran. Kill.

In the present invention, the solvent may be used alone or mixed, but it is preferable to use a mixed solvent containing two or more kinds of solvents having different functional groups. As a result, the solubility of the material is increased, and not only the generation of particles over time can be suppressed, but also a good pattern profile can be obtained. The mixed solvent containing two or more kinds of solvents having different functional groups is at least selected from a solvent having a hydroxyl group, a solvent having an ester structure, a solvent having a ketone structure, a solvent having a lactone structure, and a solvent having a carbonate structure. A mixed solvent containing two kinds is preferred. As the mixed solvent having different functional groups, the following mixed solvents (S1) to (S6) are preferable.
(S1) a mixed solvent obtained by mixing a solvent containing a hydroxyl group and a solvent not containing a hydroxyl group,
(S2) a mixed solvent obtained by mixing a solvent having an ester structure and a solvent having a ketone structure;
(S3) a mixed solvent obtained by mixing a solvent having an ester structure and a solvent having a lactone structure;
(S4) a mixed solvent obtained by mixing a solvent having an ester structure, a solvent having a lactone structure, and a solvent containing a hydroxyl group;
(S5) a solvent having an ester structure, a solvent having a carbonate structure, and a mixed solvent containing a hydroxyl group,
(S6) A mixed solvent containing at least a solvent having an ester structure, a solvent having a ketone structure, and a solvent having a lactone structure.
As a result, the generation of particles during storage of the resist solution can be reduced, and the generation of defects during application can be suppressed.

Examples of the solvent containing a hydroxyl group include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethyl lactate, and the like. Particularly preferred are propylene glycol monomethyl ether and ethyl lactate.
Examples of the solvent not containing a hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide and the like. Among these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are particularly preferred, and propylene glycol monomethyl ether acetate, ethyl ethoxypropionate. 2-heptanone and cyclohexanone are particularly preferred.
Examples of the solvent having a ketone structure include cyclohexanone and 2-heptanone, and 2-heptanone is preferable.
Examples of the solvent having an ester structure include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, and butyl acetate, and propylene glycol monomethyl ether acetate is preferable.
Examples of the solvent having a lactone structure include γ-butyrolactone.
Examples of the solvent having a carbonate structure include propylene carbonate and ethylene carbonate, with propylene carbonate being preferred.

The mixing ratio (mass) of the solvent containing a hydroxyl group and the solvent not containing a hydroxyl group in (S1) is 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 60. / 40. A mixed solvent containing 50% by mass or more of a solvent not containing a hydroxyl group is particularly preferred from the viewpoint of coating uniformity.
The mixing ratio (mass) of the solvent having an ester structure and the solvent having a ketone structure in (S2) is 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 40/60 to 80. / 20. A mixed solvent containing 50% by mass or more of a solvent having an ester structure is particularly preferable from the viewpoint of coating uniformity.
The mixing ratio (mass) of the solvent having an ester structure and the solvent having a lactone structure in (S3) is 70/30 to 99/1, preferably 80/20 to 99/1, more preferably 90/10 to 99. / 1. A mixed solvent containing 70% by mass or more of a solvent having an ester structure is particularly preferable from the viewpoint of stability over time.
In mixing the solvent having an ester structure, the solvent having a lactone structure, and the solvent containing a hydroxyl group in (S4), the solvent having an ester structure is 30 to 80% by weight, and the solvent having a lactone structure is 1 to 20% by weight. It is preferable to contain 10 to 60% by weight of a solvent containing a hydroxyl group.
When mixing the solvent having an ester structure, the solvent having a carbonate structure, and the solvent containing a hydroxyl group in (S5), the solvent having an ester structure is 30 to 80% by weight, and the solvent having a carbonate structure is 1 to 20% by weight. It is preferable to contain 10 to 60% by weight of a solvent containing a hydroxyl group.
In mixing the solvent having an ester structure, the solvent having a ketone structure, and the solvent having a lactone structure in (S6), 30 to 80% by weight of the solvent having an ester structure and 10 to 60% by weight of the solvent having a ketone structure %, And preferably 1 to 20% by weight of a solvent containing a lactone structure.

<Other additives>
The positive photosensitive composition of the present invention has further solubility in a dye, a plasticizer, a surfactant other than the fluorine and / or silicon surfactant, a photosensitizer, and a developer as necessary. A compound to be promoted and the like can be contained.

  The dissolution accelerating compound for the developer that can be used in the present invention is a low molecular weight compound having a molecular weight of 1,000 or less and having two or more phenolic OH groups or one or more carboxy groups. When it has a carboxy group, an alicyclic or aliphatic compound is preferable.

  A preferable addition amount of these dissolution promoting compounds is 2 to 50% by mass, and more preferably 5 to 30% by mass with respect to the acid-decomposable resin. 50 mass% or less is preferable at the point of development residue suppression and the pattern deformation prevention at the time of image development.

  Such phenolic compounds having a molecular weight of 1000 or less can be obtained by referring to methods described in, for example, JP-A-4-1222938, JP-A-2-28531, U.S. Pat. No. 4,916,210, European Patent No. Can be easily synthesized.

  Specific examples of alicyclic or aliphatic compounds having a carboxyl group include carboxylic acid derivatives having a steroid structure such as cholic acid, deoxycholic acid, lithocholic acid, adamantane carboxylic acid derivatives, adamantane dicarboxylic acid, cyclohexane carboxylic acid, cyclohexane Examples thereof include, but are not limited to, dicarboxylic acids.

  In the present invention, other surfactants than fluorine and / or silicon surfactants can be added. Specifically, nonionic interfaces such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan aliphatic esters, polyoxyethylene sorbitan aliphatic esters, etc. Mention may be made of activators.

  These surfactants may be added alone or in some combination.

(Pattern formation method)
The positive photosensitive composition of the present invention is used by dissolving the above components in a predetermined organic solvent, preferably the mixed solvent, filtering the solution, and applying the solution on a predetermined support as follows. The filter used for filter filtration is preferably made of polytetrafluoroethylene, polyethylene, or nylon of 0.1 microns or less, more preferably 0.05 microns or less, and still more preferably 0.03 microns or less.

For example, a substrate such as a positive photosensitive composition used in the manufacture of precision integrated circuit devices (eg,
(Silicon / silicon dioxide coating) is applied at an arbitrary thickness (usually 50 to 500 nm) by an appropriate application method such as a spinner or coater. After application, the resist film is formed by drying by spinning or baking. The bake temperature can be set as appropriate, but is usually 60 to 150 ° C, and preferably 90 to 130 ° C.

Next, exposure is performed through a mask or the like for pattern formation.
Although an exposure amount can be set suitably, it is 1-100 mJ / cm < ² > normally. After exposure, preferably, spinning or / and baking is performed, development and rinsing are performed to obtain a pattern.

  Exposure (immersion exposure) may be performed by filling a liquid (immersion medium) having a higher refractive index than air between the photosensitive film and the lens during irradiation with actinic rays or radiation. Thereby, resolution can be improved. As the immersion medium to be used, any liquid can be used as long as it has a higher refractive index than air, but pure water is preferred. Further, an overcoat layer may be further provided on the photosensitive film so that the immersion medium and the photosensitive film do not come into direct contact with each other during the immersion exposure. Thereby, the elution of the composition from the photosensitive film to the immersion medium is suppressed, and development defects are reduced.

Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, etc., but preferably far ultraviolet light having a wavelength of 250 nm or less, more preferably 220 nm or less. Specifically, KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (157 nm), X-ray, electron beam, etc. ArF excimer laser, F ₂ excimer laser, EUV (13 nm) An electron beam is preferred.

Before forming the resist film, an antireflection film may be coated on the substrate in advance.
As the antireflection film, any of an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, and amorphous silicon, and an organic film type made of a light absorber and a polymer material can be used. In addition, as the organic antireflection film, commercially available organic antireflection films such as DUV30 series, DUV-40 series manufactured by Brewer Science, AR-2, AR-3, AR-5 manufactured by Shipley, etc. may be used. it can.

In the development step, an alkaline developer is used as follows. As an alkaline developer of the resist composition, inorganic hydroxides such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, primary amines such as ethylamine and n-propylamine, Secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide and the like Alkaline aqueous solutions such as quaternary ammonium salts, cyclic amines such as pyrrole and pihelidine can be used.
Furthermore, alcohols and surfactants can be added in appropriate amounts to the alkaline developer.
The alkali concentration of the alkali developer is usually from 0.1 to 20% by mass.
The pH of the alkali developer is usually from 10.0 to 15.0.

The positive resist composition of the present invention may be applied to a multilayer resist process (particularly a three-layer resist process). The multilayer resist method includes the following processes.
(a) A lower resist layer made of an organic material is formed on a substrate to be processed.
(b) On the lower resist layer, an intermediate layer and an upper resist layer made of an organic material that crosslinks or decomposes upon irradiation are sequentially laminated.
(c) After forming a predetermined pattern in the upper resist layer, the intermediate layer, the lower layer and the substrate are sequentially etched.
As the intermediate layer, organopolysiloxane (silicone resin) or SiO ₂ coating solution (SOG) is generally used. As the lower layer resist, an appropriate organic polymer film is used, but various known photoresists may be used. For example, each series of the Fuji Film Arch FH series, FHi series, or Sumitomo Chemical PFI series can be illustrated.
The film thickness of the lower resist layer is preferably 0.1 to 4.0 μm, more preferably 0.2 to 2.0 μm, and particularly preferably 0.25 to 1.5 μm. A thickness of 0.1 μm or more is preferable from the viewpoint of antireflection and dry etching resistance, and a thickness of 4.0 μm or less is preferable from the viewpoint of aspect ratio and pattern collapse of the formed fine pattern.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to this. Examples 5 and 10 are reference examples.

Synthesis Example 1 (Synthesis of resin (RA-1))
Under a nitrogen stream, 8.8 g of cyclohexanone was placed in a three-necked flask and heated to 80 ° C. To this, 8.5 g of γ-butyrolactone methacrylate, 4.7 g of 3-hydroxyadamantyl-1-methacrylate, 8.8 g of 2-methyl-2-adamantyloxycarbonylmethyl methacrylate, polymerization initiator V-60 (manufactured by Wako Pure Chemical Industries) A solution prepared by dissolving 13 mol% of the monomer in 79 g of cyclohexanone was added dropwise over 6 hours. After completion of dropping, the reaction was further carried out at 80 ° C. for 2 hours. The reaction solution was allowed to cool and then added dropwise to a mixed solution of 900 m of methanol / 100 ml of water over 20 minutes, and the precipitated powder was collected by filtration and dried to obtain 18 g of Resin (RA-1). The weight average molecular weight of the obtained resin was 6200 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.63.

  Other resins were synthesized using the same method. The weight average molecular weight was adjusted by changing the amount of the polymerization initiator.

  Hereinafter, the structures of the resins (RA-1) to (RA-12) and the resin (RX) used in Examples and Comparative Examples are shown.

Examples 1-12 and Comparative Examples 1-4
<Resist preparation>
The components shown in Table 1 below were dissolved in a solvent to prepare a solution having a solid concentration of 8% by mass, and this was filtered through a 0.03 μm polyethylene filter to prepare a positive resist solution. The prepared positive resist solution was evaluated by the following method, and the results are also shown in Table 1.

<Resist evaluation>
An anti-reflective coating DUV-42 manufactured by Brewer Science Co., Ltd. was uniformly applied to 600 angstroms on a silicon substrate subjected to hexamethyldisilazane treatment with a spin coater, dried on a hot plate at 100 ° C. for 90 seconds, and then at 190 ° C. Heat drying was performed for 240 seconds. Thereafter, each positive resist solution was applied by a spin coater and dried at 120 ° C. for 60 seconds to form a 160 nm resist film.
This resist film was exposed with an ArF excimer laser stepper (SM = NA = 0.75, 2/3 ring zone) through a mask, and heated on a hot plate at 120 ° C. for 60 seconds immediately after the exposure. Further, the resist film was developed with an aqueous 2.38 mass% tetramethylammonium hydroxide solution at 23 ° C. for 60 seconds, rinsed with pure water for 30 seconds, and then dried to obtain a line pattern.
Pattern collapse evaluation method:
When the exposure amount that reproduces the 85nm line and space mask pattern is the optimum exposure amount and the line width of the line pattern formed by further increasing the exposure amount from the optimum exposure amount is reduced, the pattern does not collapse It was defined as the line width that resolves to. A smaller value indicates that a finer pattern is resolved without falling, and that pattern falling is less likely to occur.
Line edge roughness evaluation method:
In measuring the line edge roughness, a length measuring scanning electron microscope (SEM) is used to observe an isolated pattern of 85 nm, and the distance from the reference line where the edge should be in the range where the longitudinal edge of the line pattern is 2 μm is measured. Ten points were measured with a length measurement SEM (S-8840 manufactured by Hitachi, Ltd.), the standard deviation was obtained, and 3σ was calculated. A smaller value indicates better performance.
Profile evaluation method:
An isolated pattern of 85 nm was observed. A rectangular pattern was indicated by ◯, a slightly tapered pattern was indicated by △, and a film loss was indicated by x.

  Hereinafter, abbreviations in the table are shown.

  [Acid generator]

PAG-X: Triphenylsulfonium trifluoromethanesulfonate PAG-Y: Triphenylsulfonium nonafluorobutanesulfonate

[Basic compounds]
TPSA: Triphenylsulfonium acetate
DIA: 2,6-diisopropylaniline
TEA: Triethanolamine
DBA: N, N-dibutylaniline
PBI: 2-phenylbenzimidazole TMEA: Tris (methoxyethoxyethyl) amine
PEA: N-phenyldiethanolamine [Surfactant]
W-1: MegaFuck F176 (Dainippon Ink Chemical Co., Ltd.) (Fluorine)
W-2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.) (fluorine and silicon)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) (silicon-based)
W-4: Troisol S-366 (manufactured by Troy Chemical Co., Ltd.)
〔solvent〕
S1: Propylene glycol methyl ether acetate
S2: 2-Heptanone
S3: cyclohexanone
S4: γ-butyrolactone
S5: Propylene glycol methyl ether
S6: Ethyl lactate S7: Propylene carbonate

  From Table 2, it is clear that the positive photosensitive composition of the present invention has good pattern collapse performance and excellent line edge roughness and profile.

(Immersion exposure)
<Resist preparation>
The components of Examples 1 to 12 and Comparative Examples 1 to 4 were dissolved in a solvent to prepare a solution having a solid content concentration of 5% by mass, and this was filtered through a 0.03 μm polyethylene filter to prepare a positive resist solution. The prepared positive resist solution was evaluated by the following method.
<Resolution evaluation>
An organic antireflection film ARC29A (Nissan Chemical Co., Ltd.) was applied on a silicon wafer, and baked at 205 ° C. for 60 seconds to form a 78 nm antireflection film. A positive resist solution prepared thereon was applied and baked at 115 ° C. for 60 seconds to form a 140 nm resist film.
The wafer thus obtained was subjected to two-beam interference exposure (wet exposure) using pure water as the immersion liquid. In the two-beam interference exposure (wet), as shown in FIG. 1, a laser 1, an aperture 2, a shutter 3, three reflecting mirrors 4, 5, 6 and a condenser lens 7 are used, and a prism 8, an immersion liquid is used. The wafer 10 having an antireflection film and a resist film was exposed through (pure water) 9. The wavelength of the laser 1 was 193 nm, and the prism 8 forming a 65 nm line and space pattern was used. Immediately after the exposure, the resist pattern obtained by heating at 115 ° C. for 90 seconds, developing with an aqueous tetramethylammonium hydroxide solution (2.38%) for 60 seconds, rinsing with pure water, and spin drying is then applied to a scanning electron microscope. (Hitachi S-9260) was used for observation. When the positive resist solutions of Examples 1 to 12 were used, the 65 nm line and space pattern was resolved without causing pattern collapse. When the positive resist solutions of Comparative Examples 1 to 4 were used, pattern collapse was observed in some patterns although the 65 nm line and space pattern was resolved.
It is clear that the positive photosensitive composition of the present invention has a good image forming ability even in an exposure method using an immersion liquid.

It is the schematic of a two-beam interference exposure experiment apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser 2 Aperture 3 Shutter 4, 5, 6 Reflection mirror 7 Condensing lens 8 Prism 9 Immersion liquid 10 Wafer having antireflection film and resist film 11 Wafer stage

Claims (11)

(A) a compound capable of generating a sulfonic acid having a fluoroalkyl chain having 2 or 3 carbon atoms and not having a fluoroalkyl chain having 4 or more carbon atoms upon irradiation with actinic rays or radiation, and (B) the following general formula A positive photosensitive composition comprising a resin having an acid-decomposable repeating unit represented by (I) and capable of increasing the dissolution rate in an alkaline developer by the action of an acid.

In general formula (I),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
Ry _{1 to} Ry ₃ each independently represents an alkyl group or a cycloalkyl group. At least two members out of Ry _{1 to} Ry ₃ may be bonded to form a monocyclic or polycyclic hydrocarbon structure.
Z represents a divalent chain hydrocarbon group . The positive photosensitive composition according to claim 1, wherein the compound of component (A) is a compound that generates a sulfonic acid represented by the following general formula (S1) upon irradiation with actinic rays or radiation. object.

In the general formula (S1),
Rf represents a fluorine-substituted alkylene group having 2 or 3 carbon atoms.
A ₁ represents a divalent linking group having a single bond or a hetero atom.
B ₁ represents a hydrogen atom, a fluorine atom, a monovalent organic group having a hydrocarbon structure, a sulfonic acid group, a carboxyl group, a hydroxyl group or a cyano group.   The positive photosensitive composition according to claim 1 or 2, wherein the compound of component (A) is a compound that generates a perfluoroalkanesulfonic acid having 2 or 3 carbon atoms upon irradiation with actinic rays or radiation. object. The resin as the component (B), further, according to any one of claims 1 to 3, characterized in that a repeating unit having at least one lactone group, selected hydroxyl, cyano group and an alkali-soluble group A positive photosensitive composition.   The resin of the component (B) has a repeating unit having the lactone group, and the repeating unit is a repeating unit having a lactone structure represented by the following general formula (LC1-4). Item 5. The positive photosensitive composition according to item 4.

  In the general formula (LC1-4),
  Rb ₂ Represents a substituent.
  n ₂ Represents an integer of 0 to 4. n ₂ When R is 2 or more, there are multiple Rb ₂ May be the same or different, and a plurality of Rb ₂ They may combine to form a ring.   The positive photosensitive composition according to any one of claims 1 to 5, wherein the resin of component (B) further has a repeating unit represented by the following general formula (II).

  In general formula (II):
  Xa ₁ Represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom, and Xa in the general formula (I) ₁ Is the same.
  Rx ₁ ~ Rx _Three Each independently represents an alkyl group or a cycloalkyl group. Rx ₁ ~ Rx _Three May be combined to form a cycloalkyl group.   (A) 2 or more types of compounds of a component are included, or the compound which generate | occur | produces an acid by irradiation of actinic rays or radiation other than the compound of (A) component is further contained. The positive photosensitive composition as described in any one of 6.   The acid which contains two or more compounds of component (A) and each of the two compounds of component (A) is generated by irradiation with actinic rays or radiation has a total number of atoms other than hydrogen atoms of each other. The positive photosensitive composition according to claim 7, which is two or more different organic acids.   The resist film formed with the positive photosensitive composition as described in any one of Claims 1-8. A pattern forming method comprising the steps of exposing and developing the resist film according to claim 9 .   The pattern formation method according to claim 10, wherein the exposure is immersion exposure.

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