JP4696001B2 - 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 actinic rays or radiation such as far ultraviolet light, and a reaction using this acid as a catalyst to react the irradiated and non-irradiated areas of the active ray or radiation. It is a pattern forming material that changes the solubility in a developer and forms a pattern on a 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, an ArF excimer laser (193 nm) is used as an exposure light source, the compound having an aromatic group exhibits 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. For example, JP-A-9-73173 (Patent Document 1) describes a resist composition containing an acid-decomposable resin having an alicyclic structure. However, when forming a fine pattern with a line width of 100 nm or less, even if the resolution performance is excellent, the formed line pattern collapses, resulting in a pattern collapse problem that becomes a defect during device manufacturing. In addition, improvement of the line edge roughness performance of the line pattern has been demanded.
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-A-9-73173

  Accordingly, an object of the present invention is to provide a positive photosensitive composition having improved line edge roughness and pattern collapse even in the formation of a fine pattern of 100 nm or less, and a pattern forming method using the same.

一般式（Ｉ−１）及び（Ｉ−２）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。
Ｒｘ ₁ 及びＲｘ ₂ は、それぞれ独立に、直鎖状若しくは分岐状アルキル基又は単環環状アルキル基を表す。

一般式（ＶＩＩａ）〜（ＶＩＩｃ）中、
Ｒ _２ｃ 〜Ｒ _４ｃ は、各々独立に、水素原子、水酸基又はシアノ基を表す。ただし、Ｒ _２ｃ 〜Ｒ _４ｃ のうち少なくとも１つは、水酸基又はシアノ基を表す。
ただし、上記ポジ型感光性組成物から、酸の作用により分解し、アルカリ可溶性となる基を含む繰り返し単位（ａ’）、脂環ラクトン構造を有する繰り返し単位（ｂ’）、水酸基を置換した脂環構造をもつ繰り返し単位（ｃ’）、及び、メタクリル酸繰り返し単位（ｄ’）を含有し、メタクリル酸繰り返し単位（ｄ’）の割合が全繰り返し単位中５〜１８モル％である、酸の作用により現像液に対する溶解性が増大する樹脂（Ａ’）、及び、活性光線又は放射線の照射により酸を発生する化合物（Ｂ’）を含有するポジ型レジスト組成物は除く。
＜２＞ 一般式（Ｉ−１）又は（Ｉ−２）に於いて、Ｒｘ ₁ 及びＲｘ ₂ の内の少なくとも１つが、炭素数２以上の直鎖状若しくは分岐状アルキル基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。
＜３＞ （Ｂ）成分が、更に、一般式（Ｉ−１）又は（Ｉ−２）とは異なる酸分解性繰り返し単位を有す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）成分が、更に、アルカリ可溶性基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＞のいずれかに記載のポジ型感光性組成物。
＜５＞ 更に、（Ｆ）溶剤を含有し、該溶剤が、アルキレングリコールモノアルキルエーテルカルボキシレートと他の溶剤との混合溶剤であり、他の溶剤が、水酸基、ケトン基、ラクトン基、エステル基、エーテル基及びカーボネート基から選ばれる官能基を少なくとも１つ有する溶剤から選ばれる少なくとも１種類の溶剤であることを特徴とする上記＜１＞〜＜４＞のいずれかに記載のポジ型感光性組成物。
＜６＞ 更に、（Ｆ）溶剤を含有し、該溶剤が、プロピレングリコールモノメチルエーテルアセテートと、乳酸エチル、γブチロラクトン、プロピレングリコールモノメチルエーテル、酢酸ブチル及びシクロヘキサノンから選ばれる少なくとも１種類の溶剤との混合溶剤であることを特徴とする上記＜１＞〜＜４＞のいずれかに記載のポジ型感光性組成物。
＜７＞ 上記＜１＞〜＜６＞のいずれかに記載のポジ型感光性組成物により形成された感光性膜。
＜８＞ 上記＜７＞に記載の感光性膜を露光、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。
＜９＞ 前記感光性膜を、液浸液を介して露光することを特徴とする上記＜８＞に記載のパターン形成方法。
本発明は、上記＜１＞〜＜９＞に係る発明であるが、以下、参考のため、他の事項も含めて記載している。
（１） （Ａ）活性光線又は放射線の照射により酸を発生する化合物及び
（Ｂ）酸の作用によりアルカリ現像液に対する溶解速度が増大する樹脂
を含有するポジ型感光性組成物であって、
（Ｂ）成分が、下記（ａ１）〜（ａ３）の繰り返し単位を有することを特徴とするポジ型感光性組成物。
（ａ１）下記一般式（Ｉ−１）で表される酸分解性繰り返し単位及び／又は下記一般式（Ｉ−２）で表される酸分解性繰り返し単位、
（ａ２）ラクトン基を有する繰り返し単位及び
（ａ３）水酸基又はシアノ基を有する繰り返し単位。 <1> (A) a compound that generates an acid upon irradiation with actinic rays or radiation, and
(B) Resin whose dissolution rate in an alkaline developer is increased by the action of acid
A positive photosensitive composition containing
The positive type, wherein the component (B) has the following repeating units (a1) to (a3)
Photosensitive composition.
(A1) An acid-decomposable repeating unit represented by the following general formula (I-1) and / or an acid-decomposable repeating unit represented by the following general formula (I-2),
(A2) a repeating unit having a lactone group and
(A3) A repeating unit having a partial structure represented by any one of the following general formulas (VIIa) to (VIId).

In general formulas (I-1) and (I-2),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
Rx ₁ and Rx ₂ each independently represents a linear or branched alkyl group or a monocyclic alkyl group.

In general formulas (VIIa) to (VIIc),
R _{2c to} R _4c each independently represents a hydrogen atom, a hydroxyl group or a cyano group. However, at least one of R _{2c to} R _4c represents a hydroxyl group or a cyano group.
However, the above-mentioned positive photosensitive composition is decomposed by the action of an acid, a repeating unit (a ′) containing a group that becomes alkali-soluble, a repeating unit (b ′) having an alicyclic lactone structure, and a fat substituted with a hydroxyl group A repeating unit (c ′) having a ring structure and a repeating unit of methacrylic acid (d ′), wherein the ratio of the repeating unit of methacrylic acid (d ′) is 5 to 18 mol% in all repeating units. A positive resist composition containing a resin (A ′) whose solubility in a developing solution is increased by action and a compound (B ′) that generates an acid upon irradiation with actinic rays or radiation is excluded.
<2> In general formula (I-1) or (I-2), at least one of Rx ₁ and Rx ₂ is a linear or branched alkyl group having 2 or more carbon atoms The positive photosensitive composition as described in <1> above.
<3> The component (B) further has an acid-decomposable repeating unit different from the general formula (I-1) or (I-2), according to the above <1> or <2> Positive photosensitive composition.
<4> The positive photosensitive composition according to any one of <1> to <3>, wherein the component (B) further has a repeating unit having an alkali-soluble group.
<5> Further, (F) a solvent is contained, the solvent is a mixed solvent of an alkylene glycol monoalkyl ether carboxylate and another solvent, and the other solvent is a hydroxyl group, a ketone group, a lactone group, an ester group. The positive photosensitive resin as described in any one of <1> to <4> above, which is at least one solvent selected from solvents having at least one functional group selected from an ether group and a carbonate group Composition.
<6> Further, (F) a solvent, which is a mixture of propylene glycol monomethyl ether acetate and at least one solvent selected from ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether, butyl acetate and cyclohexanone The positive photosensitive composition as described in any one of <1> to <4> above, which is a solvent.
<7> A photosensitive film formed from the positive photosensitive composition according to any one of <1> to <6>.
<8> A pattern forming method comprising a step of exposing and developing the photosensitive film according to <7>.
<9> The pattern forming method according to <8>, wherein the photosensitive film is exposed through an immersion liquid.
The present invention is an invention according to the above <1> to <9>, but is described below including other matters for reference.
(1) A positive photosensitive composition comprising (A) a compound that generates an acid upon irradiation with actinic rays or radiation, and (B) a resin that increases the dissolution rate in an alkali developer by the action of the acid,
The positive photosensitive composition, wherein the component (B) has the following repeating units (a1) to (a3):
(A1) An acid-decomposable repeating unit represented by the following general formula (I-1) and / or an acid-decomposable repeating unit represented by the following general formula (I-2),
(A2) a repeating unit having a lactone group and (a3) a repeating unit having a hydroxyl group or a cyano group.

In general formulas (I-1) and (I-2),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
Rx ₁ and Rx ₂ each independently represents a linear or branched alkyl group or a monocyclic alkyl group.

(2) In the general formula (I-1) or (I-2), at least one of Rx ₁ and Rx ₂ is a linear or branched alkyl group having 2 or more carbon atoms The positive photosensitive composition as described in (1).

  (3) The positive electrode according to (1) or (2), wherein the component (B) further has an acid-decomposable repeating unit different from the general formula (I-1) or (I-2). Type photosensitive composition.

  (4) The positive photosensitive composition as described in any one of (1) to (3), wherein the component (B) further has a repeating unit having an alkali-soluble group.

  (5) Further, (F) a solvent is contained, and the solvent is a mixed solvent of an alkylene glycol monoalkyl ether carboxylate and another solvent, and the other solvent is a hydroxyl group, a ketone group, a lactone group, an ester group. The positive photosensitive composition according to any one of (1) to (4), wherein the positive photosensitive composition is at least one solvent selected from solvents having at least one functional group selected from an ether group and a carbonate group object.

(6) Further, (F) a solvent, which is a mixture of propylene glycol monomethyl ether acetate and at least one solvent selected from ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether, butyl acetate and cyclohexanone The positive photosensitive composition as described in any one of (1) to (4), which is a solvent.

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

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a positive photosensitive composition having improved line edge roughness and pattern collapse even in the formation of a fine pattern of 100 nm or less, and a pattern forming method using the same.

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 acid upon irradiation with actinic ray or radiation The positive photosensitive composition of the present invention is a compound that generates acid upon irradiation with actinic ray or radiation (also referred to as “acid generator”). Containing.
Examples of such an acid generator include a photoinitiator for photocationic polymerization, a photoinitiator for photoradical polymerization, a photodecolorant for dyes, a photochromic agent, or an actinic ray or radiation used for a microresist. A known compound that generates an acid by irradiation and a mixture thereof can be appropriately selected and used.

  Examples thereof include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonates.

  Further, a group that generates an acid upon irradiation with these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, for example, US Pat. No. 3,849,137, German Patent No. 3914407. JP, 63-26653, JP, 55-164824, JP, 62-69263, JP, 63-146038, JP, 63-163452, JP, 62-153853, The compounds described in JP-A 63-146029 can be used.

  Furthermore, compounds capable of generating an acid by light described in US Pat. No. 3,779,778, European Patent 126,712 and the like can also be used.

  Among the compounds that generate an acid upon irradiation with actinic rays or radiation, compounds represented by the following general formulas (ZI), (ZII), and (ZIII) can be exemplified.

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 is substituted with a perfluoroalkylene group having 4 or less carbon atoms, more preferably 2 to 4 carbon atoms, more preferably 2 to 3 carbon atoms, 1 to 4 fluorine atoms and / or 1 to 3 fluoroalkyl groups. Represents a phenylene 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 alkyl group or an aryl group. The alkyl group, cyclic alkyl group, and aryl group may be substituted, but preferably do not have a fluorine atom as a substituent.

In 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. A perfluoroalkylene group having 2 to 4 carbon atoms is preferred. 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 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 corresponding groups in the compounds (ZI-1), (ZI-2) and (ZI-3) described later.

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.
In the arylsulfonium compound, all of R _{201 to} R ₂₀₃ may be an aryl group, or R ₂₀₁
Some of to R ₂₀₃ is an aryl group with the remaining being 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 linear or branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, and linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, particularly 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.

Next, the compound (ZI-2) will be described.
Compound (ZI-2) is a compound in the case where R _{201 to} R ₂₀₃ in formula (ZI) each independently represents an organic group containing no aromatic ring. Here, the aromatic ring includes an aromatic ring containing 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 is preferably include 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 alkyl group as R ₂₀₁ to R ₂₀₃ may be linear, branched 2-oxoalkyl group, more preferably an alkoxymethyl 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.
Linear as R ₂₀₁ to R _203, branched or cyclic 2-oxoalkyl group may preferably be a group having a 2-position> C = O in the above-described alkyl 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-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 _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.
X ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of X ^{− in} formula (I).

The alkyl group as R _{1c to} R _7c is, for example, a linear or branched alkyl group having 1 to 20 carbon atoms, preferably a linear or branched alkyl group having 1 to 12 carbon atoms (for example, a methyl group). , Ethyl group, linear or branched propyl group, linear or branched butyl group, linear or branched pentyl group).
Preferable examples of the cycloalkyl group as R _{1c to} R _7c include a cycloalkyl group having 3 to 8 carbon atoms (for example, a cyclopentyl group and a cyclohexyl group).
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 alkoxymethyl group.
_Examples of the cycloalkyl group as R _x and R _y include the same cycloalkyl groups 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, or 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 formulas (ZII) and (ZIII),
R ₂₀₄ to R ₂₀₇ each independently represents an aryl group, an alkyl group or a cycloalkyl group.
Phenyl group and a naphthyl group are preferred as the aryl group of R ₂₀₄ to R _207, 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 decompose upon irradiation with actinic rays or radiation to generate an acid, more preferred are compounds represented by general formulas (ZI) to (ZIII), and even more preferred are those represented by general formula (ZI). Particularly preferred are compounds represented by 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.

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

  Among the compounds that generate an acid upon irradiation with actinic rays or radiation, examples of particularly preferable compounds are listed below.

An acid generator 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 acid generator in the composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and still more preferably 1 based on the total solid content of the positive photosensitive composition. -7% by mass.

[2] (B) Resin whose dissolution rate in an alkaline developer is increased by the action of an acid Resin (“(B) 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. ) Component ”) has the following repeating units (a1) to (a3).
(A1) An acid-decomposable repeating unit represented by the following general formula (I-1) and / or an acid-decomposable repeating unit represented by the following general formula (I-2),
(A2) a repeating unit having a lactone group and (a3) a repeating unit having a hydroxyl group or a cyano group.

In general formulas (I-1) and (I-2),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
Rx ₁ and Rx ₂ each independently represents a linear or branched alkyl group or a monocyclic alkyl group.

The component (B) has a repeating unit represented by the general formula (I-1) and / or an acid-decomposable repeating unit represented by the general formula (I-2).
In the general formulas (I-1) and (I-2), Xa ₁ represents a hydrogen atom, an alkyl group (which may be substituted with a hydroxyl group, an alkoxy group or a halogen atom), a cyano group or a halogen atom, preferably Is a hydrogen atom or a methyl group.
Rx ₁ and Rx ₂ each independently represents a linear or branched alkyl group or a monocyclic alkyl group. As a linear alkyl group, a C1-C4 alkyl group is preferable and a methyl group, an ethyl group, n-propyl group, and n-butyl group are preferable. Examples of the branched alkyl group include an isopropyl group and an isobutyl group. Examples of the monocyclic alkyl group include a cyclopentyl group and a cyclohexyl group.
In general formulas (I-1) and (I-2), at least one of Rx _{1 and} Rx ₂ is preferably a linear or branched alkyl group having 2 or more carbon atoms, more preferably Rx. _At least one of ₁ or Rx ₂ is an ethyl group or an isopropyl group. Preferred combinations of Rx ₁ and Rx ₂ include: Rx ₁ is a methyl group, Rx ₂ is an ethyl group, Rx ₁ is a methyl group, Rx ₂ is an isopropyl group, Rx ₁ is an isopropyl group, Rx ₂ is an ethyl group, Rx ₁ , Rx _{2 is} both an ethyl group, Rx ₁ and Rx ₂ are both methyl groups, Rx ₁ and Rx ₂ are both isopropyl groups, and preferably Rx ₁ is a methyl group, Rx ₂ is an ethyl group, and Rx ₁ is a methyl group Rx ₂ is an isopropyl group, Rx ₁ is an isopropyl group, Rx ₂ is an ethyl group, both Rx ₁ and Rx ₂ are ethyl groups, and both Rx ₁ and Rx ₂ are isopropyl groups.

Specific examples of the preferred repeating unit (a1) are shown below, but the present invention is not limited thereto.

  The resin of component (B) having the repeating units represented by general formulas (I-1) and (I-2) corresponds to the repeating units represented by general formulas (I-1) and (I-2). It can be synthesized by polymerizing a polymerizable compound. The polymerizable compound corresponding to the repeating units represented by the general formulas (I-1) and (I-2) can be synthesized by using a general synthesis method. For example, it can be synthesized by the method shown below.

In the above formula, Xa _1, Rx ₁ and Rx ₂ are formula (I-1), which is synonymous in, and Xa _1, Rx ₁ and Rx _{2 (I-2).}

The component (B) may have an acid-decomposable repeating unit other than the repeating units represented by the general formulas (I-1) and (I-2).
Examples of the acid-decomposable repeating unit other than the repeating units represented by the general formulas (I-1) and (I-2) include the repeating units represented by the following general formula (I-1a) or (I-2a). preferable.

In general formulas (I-1a) and (I-2a),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom, and is the same as Xa _{1 in} formulas (I-1) and (I-2).
Ry _{1 to} Ry ₃ each independently represents a linear or branched alkyl group or a polycyclic alkyl group.
Z represents an atomic group necessary for forming a monocyclic or polycyclic alkyl group together with a carbon atom.
The linear or branched alkyl group in Ry _{1 to} Ry ₃ is preferably a methyl group, an ethyl group, or an isopropyl group.
The polycyclic alkyl group in Ry _{1 to} Ry ₃ is preferably an adamantyl group or a norbornyl group.
The monocyclic or polycyclic alkyl group that Z forms with a carbon atom is preferably a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, a tetracyclodecanyl group, or a tetracyclododecanyl group.
By using another acid-decomposable repeating unit in combination, performance balance such as PEB temperature dependency and resolving power is improved.

  Specific examples of the repeating unit represented by (I-1a) are shown below, but the present invention is not limited thereto.

In specific examples,
Rx represents H, CH ₃ , CF ₃ or CH ₂ OH.
Ry ₁ and Ry ₂ each independently represents an alkyl group having 1 to 4 carbon atoms.

  Specific examples of the repeating unit represented by (I-2a) are shown below, but the present invention is not limited thereto.

In specific examples,
Rx represents H, CH ₃ , CF ₃ or CH ₂ OH.
Ry ₁ represents an alkyl group having 1 to 4 carbon atoms.

  Among the above specific examples, (I-1a-1), (I-1a-7), (I-2a-1), (I-2a-4), (I-2a-6), (I- 2a-8) and (I-2a-9) are preferred as the acid-decomposable repeating unit used in combination.

The component (B) has a repeating unit having a lactone group.
As the lactone group, any group can be used as long as it has a lactone structure, but it is preferably a group containing a 5- to 7-membered ring lactone structure. Those in which other ring structures are condensed to form a spiro structure are preferred. It is more preferable to have a repeating unit having a group having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16). Further, a group having a lactone structure may be directly bonded to the main chain. Preferred lactone structures are (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), and (LC1-14), particularly preferably (LC1-4 ). By using a specific lactone structure, line edge roughness and development defects are improved.

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 preferred are alkyl groups having 1 to 4 carbon atoms, cyano groups, and acid-decomposable groups. n2 represents an integer of 0 to 4. When n2 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 group having a lactone structure represented by any 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 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.

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

The component (B) 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 of 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 _{2c to} R _4c each independently represents a hydrogen atom, a hydroxyl group or a cyano group. However, at least one of R _{2c to} R _4c represents a hydroxyl group or a cyano group. Preferably, one or two of R _{2c to} R _4c are a hydroxyl group and the remainder is a hydrogen atom. In (VIIa), more preferably, two of R _{2c to} R _4c are hydroxyl groups and the rest are hydrogen atoms.

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

In general formulas (AIIa) to (AIId),
R _1c represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.
R _2c to R _4c are in the general formula (VIIa) ~ (VIId), synonymous with R _2c to R _4c.

  Specific examples of the repeating units represented by the general formulas (AIIa) to (AIId) are given below, but the present invention is not limited thereto.

  The 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 group in which the α-position is substituted with an electron-withdrawing group (preferably represented by the following general formula (F1) Group) and a repeating unit having a carboxyl group is more preferable.

In general formula (F1),
R _{50 to} R ₅₅ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{50 to} R ₅₅ represents a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and all of R _{50 to} R ₅₅ are preferably fluorine atoms. .
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. Most preferred is a repeating unit 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.

  The component (B) may further have 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 repeating units of 1-adamantyl (meth) acrylate, tricyclodecanyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like.

  In addition to the above repeating structural units, component (B) adjusts dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general required properties of resist, such as resolution, heat resistance, and sensitivity. For this purpose, various repeating structural units can be included.

  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 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), the content 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 resolution, heat resistance, and sensitivity. It is set appropriately in order to adjust etc.

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

  As the component (B), all of the repeating units are preferably composed of (meth) acrylate 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 acid-decomposable units other than the acid-decomposable repeating units represented by the general formula (I-1) or (I-2) of 20 to 50 mol% and the general formulas (I-1) and (I-2) are used. 0 to 30 mol% of repeating units, 20 to 50 mol% of repeating units having a lactone group, 5 to 30 mol% of repeating units having a hydroxyl group or a cyano group, 0 to 15 mol% of repeating units having an alkali-soluble group, and other It is a copolymer containing 0 to 20 mol% of repeating units.

  The 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 heating is performed, 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 and 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 that used in the resist 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 initiators include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. A chain transfer agent such as a thiol compound may be used in combination with the polymerization initiator. 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 component (B) is preferably 1,000 to 200,000, more preferably 3,000 to 20,000, most preferably 5,000 to 15, as a polystyrene-converted value by the GPC method. 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 molecular weight distribution is usually 1 to 5, preferably 1 to 3, more preferably 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.

In the positive photosensitive composition of the present invention, the blending amount of the component (B) in the whole composition is preferably 60 to 99% by mass, more preferably 80 to 98% by mass in the total solid content.
In the present invention, the component (B) may be used alone or in combination.

(B2) Resin that does not have a group that decomposes by the action of an acid The positive photosensitive composition of the present invention has a resin that does not have a group that decomposes by the action of an acid (hereinafter also referred to as “component (B2)”). It may contain.
“No acid-decomposable group” means that there is no or very little decomposability due to the action of an acid in an image forming process in which the positive photosensitive composition of the present invention is usually used. It has no group that contributes to image formation by decomposition. Examples of such a resin include a resin having an alkali-soluble group and a resin having a group that is decomposed by the action of an alkali and improves the solubility in an alkali developer.
As the component (B2), a resin having at least one repeating unit selected from a repeating unit derived from a (meth) acrylic acid derivative and a repeating unit derived from an alicyclic olefin derivative is preferable.
The alkali-soluble group contained in the component (B2) includes a carboxyl group, a phenolic hydroxyl group, an aliphatic hydroxyl group substituted at the 1- or 2-position with an electron-withdrawing group, and an amino group substituted with an electron-withdrawing group ( For example, a sulfonamide group, a sulfonimide group, a bissulfonylimide group), a methylene group substituted with an electron-withdrawing group or a methine group (for example, a methylene group substituted with at least two selected from a ketone group and an ester group, a methine group) ) Is preferred.
The group that decomposes by the action of an alkali contained in the component (B2) and increases the solubility in an alkali developer is preferably a lactone group or an acid anhydride group, and more preferably a lactone group.
The component (B2) may have another repeating unit other than the above. As other repeating units, an appropriate functional group can be introduced in consideration of dry etching resistance, hydrophilicity / hydrophobicity, interaction property and the like.
As other repeating units, a repeating unit having a polar functional group such as a hydroxyl group, a cyano group, a carbonyl group, an ester group, a repeating unit having a monocyclic or polycyclic hydrocarbon structure, a silicon atom, a halogen atom, a fluoroalkyl group Or a repeating unit having a plurality of these functional groups.

  Specific examples of the preferred component (B2) are shown below, but the present invention is not limited thereto.

  The amount of component (B2) added is 0 to 50% by mass with respect to component (B), preferably 0 to 30% by mass and more preferably 0 to 20% by mass with respect to component (B).

[3] (C) A 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 contains an alkali-soluble group, a hydrophilic group A dissolution control compound having a molecular weight of 3000 or less (hereinafter referred to as “component (C)” having at least one selected from a group and an acid-decomposable group (a group capable of decomposing by the action of an acid and releasing an alkali-soluble group or a hydrophilic group) Or a “solubility controlling compound”).
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 in the present invention 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.

[4] (D) Basic compound The positive photosensitive composition of the present invention is a basic compound for reducing the change in performance over time from exposure to heating, or for controlling the diffusibility of acid generated by exposure in the film. It is preferable to contain a functional compound.

Examples of basic compounds include nitrogen-containing basic compounds and onium salt compounds.
Preferable nitrogen-containing basic compound structures include compounds having partial structures represented by the following 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 to 1 carbon atoms. A 20 hydroxyalkyl group or a C 3-20 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.

[5] (E) Fluorine and / or Silicone Surfactant The positive photosensitive composition of the present invention further comprises fluorine and / or silicon surfactant (fluorine surfactant, silicon surfactant and It is preferable to contain any one of surfactants containing both fluorine atoms and silicon atoms, or two or more thereof.
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, the surfactant is derived from a fluoroaliphatic compound produced by a telomerization method (also called telomer method) or an oligomerization method (also called 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). %.

[6] (F) 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. Preferable functional groups contained in the solvent include ester groups, lactone groups, hydroxyl groups, ketone groups, and carbonate groups. As the mixed solvent having different functional groups, the following mixed solvents (S1) to (S5) 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 mixed solvent containing a solvent having an ester structure, a solvent having a carbonate structure, and a hydroxyl group.
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 most preferred.
Examples of the solvent having a ketone structure include cyclohexanone and 2-heptanone, and cyclohexanone 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 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 is 1/99 to 99/1, preferably 10/90 to 90/10, and 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 is 70/30 to 99/1, preferably 80/20 to 99/1, and 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.
When mixing a solvent having an ester structure, a solvent having a lactone structure, and a solvent containing a hydroxyl group, the solvent having an ester structure is 30 to 80% by mass, the solvent having a lactone structure is 1 to 20% by mass, and the hydroxyl group is contained. It is preferable to contain 10-60 mass% of solvent to do.
When mixing a solvent having an ester structure, a solvent having a carbonate structure, and a solvent containing a hydroxyl group, the solvent having an ester structure is 30 to 80% by mass, the solvent having a carbonate structure is 1 to 20% by mass, and the hydroxyl group is contained. It is preferable to contain 10-60 mass% of solvent to do.

A preferable embodiment of these solvents is a solvent containing an alkylene glycol monoalkyl ether carboxylate (preferably propylene glycol monomethyl ether acetate), more preferably a mixed solvent of an alkylene glycol monoalkyl ether carboxylate and another solvent. And the other solvent is at least one solvent selected from solvents having at least one functional group selected from a hydroxyl group, a ketone group, a lactone group, an ester group, an ether group, and a carbonate group. A particularly preferable mixed solvent is a mixed solvent of at least one selected from ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether, butyl acetate, and cyclohexanone, and propylene glycol monomethyl ether acetate.
The development defect performance can be improved by selecting an optimum solvent.

<Other additives>
The positive photosensitive composition of the present invention may further contain a dye, a plasticizer, a surfactant other than the component (E), a photosensitizer, a compound that promotes solubility in a developer, and the like as necessary. It can be included.

  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.

  The 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 component (B). 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, a surfactant other than the above (E) fluorine and / or silicon surfactant may 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 each component in a predetermined solvent, preferably the mixed solvent, filtering the solution, and then 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 positive photosensitive composition is coated on a substrate (eg, silicon / silicon dioxide coating) used in the manufacture of precision integrated circuit elements by a suitable coating method such as a spinner or coater, dried, and photosensitive. A film is formed.
The photosensitive film is irradiated with actinic rays or radiation through a predetermined mask, preferably baked (heated), developed and rinsed. Thereby, a good pattern can be obtained.
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.

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.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to this.

Synthesis Example 1 (Synthesis of Monomer A)
Under a nitrogen stream, a solution prepared by dissolving 48.3 g of methylcyclohexanecarboxylate in 100 ml of THF was added to 250 ml of a 3.4N-methylmagnesium bromide / ether solution over 1 hour. The mixture was stirred at room temperature for 2 hours, and 100 ml of 2N aqueous hydrochloric acid solution was added to the reaction solution. The reaction solution was concentrated, and ethyl acetate was added thereto. The solution was filtered through silica gel and concentrated to give the crude product. This was purified by column chromatography to obtain 32 g of 2-cyclohexyl-2-propanol.
Under a nitrogen stream, 32 g of 2-cyclohexyl-2-propanol was dissolved in 100 ml of THF and cooled to -78 ° C. To this, 144 ml of 1.6N-n-butyllithium / hexane solution was added over 1 hour. After stirring for 30 minutes, the temperature was raised to room temperature. To this, 24.1 g of methacrylic acid chloride was added over 30 minutes. After reacting at room temperature for 1 hour, 100 ml of water was added, and the mixture was further stirred for 30 minutes. This was extracted three times with ethyl acetate, and the organic phase was washed with water, dried and concentrated to obtain a crude product. This was purified by column chromatography to obtain 24 g of the following monomer A.

Synthesis Example 2 (Synthesis of Monomer C)
The monomer A was synthesized using the same method except that methyl magnesium bromide was changed to ethyl magnesium bromide.

Synthesis Example 3 (Synthesis of Monomer E)
A solution prepared by dissolving 40 g of cyclohexol methyl ketone in 100 ml of THF was added to 143 ml of 3N-ethylmagnesium bromide / ether solution over 1 hour. The mixture was stirred at room temperature for 2 hours, and 200 ml of 2N hydrochloric acid aqueous solution was added to the reaction solution. This was extracted three times with ethyl acetate, and the organic phase was washed with water, dried and concentrated to obtain a crude product. This was purified by column chromatography to obtain 28 g of 2-cyclohexyl-2-butanol.
The following monomer E was obtained by methacrylic esterifying this using the same method as the synthesis of monomer A.

Synthesis Example 4 (Synthesis of monomers B, D, and F)
The monomers A, C, and E were synthesized using the same method except that methacrylic acid chloride was changed to acrylic acid chloride.

Synthesis Example 5 (Synthesis of monomers G to L)
In the synthesis of monomers A to F, the synthesis was performed using the same method except that the corresponding cyclopentane derivative was used as a raw material.

Synthesis Example 1 (Synthesis of resin (RA-1))
Under a nitrogen stream, 8.6 g of cyclohexanone was placed in a three-necked flask and heated to 80 ° C. 8.4 g of the following monomer A, 4.7 g of 3-hydroxyadamantyl methacrylate, 8.9 g of norbornane lactone methacrylate, and 8 mol% of the polymerization initiator V-601 (manufactured by Wako Pure Chemical Industries) are dissolved in 79 g of cyclohexanone. The solution 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 700 m of hexane / 300 ml of ethyl acetate over 20 minutes, and the precipitated powder was collected by filtration and dried to obtain 19 g of Resin (RA-1). The weight average molecular weight of the obtained resin was 5400 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.60.

  Other resins were synthesized using the same method.

  Hereinafter, the structures, weight average molecular weights (Mw) and dispersities (Mw / Mn) of the resins (RA-1) to (RA-21) and (RX-1) to (RX-5) used in Examples and Comparative Examples ).

Examples 1-24 and Comparative Examples 1-2
<Resist preparation>
The components shown in Tables 1 and 2 below were dissolved in a solvent to prepare a solution having a solid content of 9% by mass, and this was filtered through a 0.03 m 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 Tables 1 and 2.
Examples 7 and 14 are to be read as “reference examples”.

[Acid generator]
The acid generators in the table are shown below.

Abbreviations in the table are as follows.
[Basic compounds]
TPI: 2,4,5-triphenylimidazole TPSA: triphenylsulfonium acetate DIA: 2,6-diisopropylaniline TEA: triethanolamine TPA: tripentylamine 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: Troysol 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

<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 110 ° C. for 90 seconds to form a 160 nm resist film.
This resist film was exposed with an ArF excimer laser stepper (SML NA = 0.75, 2/3 ring zone) through a mask, and heated on a hot plate at 120 ° C. for 90 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 line width of the line pattern formed by increasing the exposure amount from the optimal exposure amount is reduced to the optimal exposure amount, the exposure amount for reproducing the 80 nm line and space 1: 1 mask pattern Defined with line width that resolves without falling down. The smaller the value, the finer pattern is resolved without falling, and the pattern collapse is less likely to occur and the resolution is higher.
Line edge roughness evaluation method:
Using a length-measuring scanning electron microscope (SEM), observe a 80 nm line-and-space 1: 1 pattern and measure the distance from the reference line where the edge of the line pattern should be 5 μm long. 50 points were measured by SEM (Hitachi, Ltd. S-8840), the standard deviation was obtained, and 3σ was calculated. A smaller value indicates better performance.

  From Tables 1 and 2, it is clear that the positive photosensitive composition of the present invention has improved pattern collapse and line edge roughness.

(Immersion exposure)
<Resist preparation>
The components of Examples 1 to 24 and Comparative Examples 1 and 2 were dissolved in a solvent to prepare a solution having a solid content concentration of 7% 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 onto 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 150 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, liquid The wafer 10 having an antireflection film and a resist film was exposed through an immersion liquid (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 24 were used, a 65 nm line and space pattern was resolved without causing pattern collapse. When the positive resist solutions of Comparative Examples 1 and 2 were used, a 65 nm line and space pattern was resolved, but pattern collapse was observed in some patterns.
It is clear that the positive photosensitive composition of the present application has a good image forming ability even in an exposure method through 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 (9)

A positive photosensitive composition comprising (A) a compound that generates an acid upon irradiation with actinic rays or radiation, and (B) a resin that increases the dissolution rate in an alkali developer by the action of the acid,
The positive photosensitive composition, wherein the component (B) has the following repeating units (a1) to (a3):
(A1) An acid-decomposable repeating unit represented by the following general formula (I-1) and / or an acid-decomposable repeating unit represented by the following general formula (I-2),
(A2) A repeating unit having a lactone group and (a3) a repeating unit having a partial structure represented by any one of the following general formulas (VIIa) to (VIId) .

In general formulas (I-1) and (I-2),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
Rx ₁ and Rx ₂ each independently represents a linear or branched alkyl group or a monocyclic alkyl group.

In general formulas (VIIa) to (VIIc),
R _{2c to} R _4c each independently represents a hydrogen atom, a hydroxyl group or a cyano group. However, at least one of R _{2c to} R _4c represents a hydroxyl group or a cyano group.
However, the above-mentioned positive photosensitive composition is decomposed by the action of an acid, a repeating unit (a ′) containing a group that becomes alkali-soluble, a repeating unit (b ′) having an alicyclic lactone structure, and a fat substituted with a hydroxyl group A repeating unit (c ′) having a ring structure and a repeating unit of methacrylic acid (d ′), wherein the ratio of the repeating unit of methacrylic acid (d ′) is 5 to 18 mol% in all repeating units. A positive resist composition containing a resin (A ′) whose solubility in a developing solution increases by action and a compound (B ′) that generates an acid upon irradiation with actinic rays or radiation is excluded. In the general formula (I-1) or (I-2), at least one of Rx ₁ and Rx ₂ is a linear or branched alkyl group having 2 or more carbon atoms. Item 2. The positive photosensitive composition according to item 1.   The positive photosensitive composition according to claim 1 or 2, wherein the component (B) further has an acid-decomposable repeating unit different from the general formula (I-1) or (I-2). .   The positive photosensitive composition according to claim 1, wherein the component (B) further has a repeating unit having an alkali-soluble group.   Furthermore, (F) a solvent is contained, the solvent is a mixed solvent of an alkylene glycol monoalkyl ether carboxylate and another solvent, and the other solvent is a hydroxyl group, a ketone group, a lactone group, an ester group, an ether group. 5. The positive photosensitive composition according to claim 1, wherein the positive photosensitive composition is at least one solvent selected from solvents having at least one functional group selected from carbonate groups.   Further, (F) a solvent is contained, and the solvent is a mixed solvent of propylene glycol monomethyl ether acetate and at least one solvent selected from ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether, butyl acetate and cyclohexanone. The positive photosensitive composition according to any one of claims 1 to 4, wherein:   The photosensitive film | membrane formed with the positive photosensitive composition in any one of Claims 1-6. A pattern forming method comprising: exposing and developing the photosensitive film according to claim 7 .   The pattern forming method according to claim 8, wherein the photosensitive film is exposed through an immersion liquid.

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