JP2008268743A - Positive photosensitive composition and pattern forming method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive photosensitive composition which improves pattern collapse even in the formation of a fine pattern of ≤100 nm and a pattern forming method using the same, with respect to a positive photosensitive composition for use in the production process of a semiconductor such as IC, in the production of a circuit board of liquid crystal, thermal head and the like or in other photofabrication processes and a pattern forming method using the same. <P>SOLUTION: The positive photosensitive composition comprises (A) a compound capable of generating an acid upon irradiation with actinic rays or radiation, and (B) a resin which has a repeating unit (B1) having a tertiary ester group substituted by an alkoxycarbonyl group, and decomposes by the action of an acid to increase its solubility in an alkali developer. The pattern forming method using the same is also provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

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, 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. Patent Document 1 describes a resist composition containing an acid-decomposable resin having an alicyclic structure. Patent Documents 2 to 5 disclose resist compositions using a resin having an acid-decomposable repeating unit substituted with an ester group. However, when a fine pattern having a line width of 100 nm or less is formed, the formed line pattern collapses, and improvement of pattern collapse that becomes a defect during device manufacturing has been demanded.

JP-A-9-73173 Japanese Patent Laid-Open No. 11-15162 JP 11-218924 A JP 11-223950 A JP 2000-241977

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

  The present invention is as follows.

(1) (A) a compound that generates an acid upon irradiation with actinic rays or radiation, and (B) a repeating unit (B1) having a group represented by the following general formula (I), which decomposes by the action of an acid And a positive photosensitive composition comprising a resin having increased solubility in an alkali developer.

In general formula (I),
Rx ₁ and Rx ₂ each independently represents an alkyl group or a cycloalkyl group.
Rx ₃ represents a hydrogen atom, an alkyl group or a cycloalkyl group.
Ry represents an alkyl group or a cycloalkyl group.
At least two of Rx _{1 to} Rx ₃ and Ry may be bonded to form a ring structure.

(2) In the formula (I), at least one of the Rx ₁ and Rx ₂ are either have a polycyclic hydrocarbon structure having 7 or more carbon atoms, carbon Rx ₁ and Rx ₂ are bonded to The positive photosensitive composition as described in (1), which forms a polycyclic hydrocarbon structure having a number of 7 or more.

  (3) The positive photosensitive composition as described in (1) or (2), wherein in the general formula (I), Ry is a cycloalkyl group having 7 or more carbon atoms.

(4) The positive type according to any one of (1) to (3), wherein the component (B) further has at least one repeating unit selected from the following (B2) to (B4): Photosensitive composition.
(B2) a repeating unit having a cyclic hydrocarbon structure and a lactone structure,
(B3) a repeating unit having a hydroxyl group and (B4) a repeating unit having a cyano group.

(5) The component (A) contains at least one compound capable of generating an acid selected from the following (a) to (c) upon irradiation with an actinic ray or radiation: (1) to (4) The positive photosensitive composition as described in any one of 1).
(A) a fluorine-substituted alkanesulfonic acid having 2 or more carbon atoms,
(B) Bis (alkylsulfonyl) imidic acid and (c) Aromatic sulfonic acid substituted with a fluorine atom or a group having a fluorine atom.

  (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.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a positive photosensitive composition in which pattern collapse is improved 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).

(A) Compound that generates acid upon irradiation with actinic ray or radiation The positive photosensitive composition of the present invention contains a compound that generates acid upon irradiation with actinic ray or radiation (also referred to as “acid generator”). .
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, 3 to 5 fluorine atoms and / or 1 to 3 fluoroalkyl groups. Represents a phenylene group.
Ax represents a single bond or a divalent linking group (preferably —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.

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.
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.
Aryl group, alkyl group of R ₂₀₁ to R _203, cycloalkyl group, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (for example, 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 may be substituted. 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 (eg, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, a nitro group, or the like.

  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 the same non-nucleophilic anion as X ^{− in} the general formula (ZI).

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.
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 or branched 2-oxoalkyl group 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 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 non-nucleophilic anion as X ^{− in} formula (ZI).

  Among the compounds that generate an acid upon irradiation with actinic rays or radiation, 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 preferable embodiment of the acid generator is a compound in which, in the structure of the general formula (ZI), X ⁻ is an anion represented by the general formula (AN1), (AN3) or (AN4).

The compound that generates an acid upon irradiation with actinic rays or radiation is preferably a compound that generates an acid selected from the following (a) to (c) upon irradiation with an actinic ray or radiation.
(A) a fluorine-substituted alkanesulfonic acid having 2 or more carbon atoms,
(B) Bis (alkylsulfonyl) imidic acid and (c) Aromatic sulfonic acid substituted with a fluorine atom or a group having a fluorine atom.
That is, Rc ₁ is an acid represented by the general formula (AC1), which is a fluorine-substituted alkyl group having 2 or more carbon atoms or a fluorine atom or an aromatic group substituted by a group having a fluorine atom, or Rc ₃ And an acid represented by the general formula (AC2) in which Rc ₄ is an alkyl group.

  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.

(B) Resin having a repeating unit (B1) having a group represented by the general formula (I), decomposing by the action of an acid, and increasing the solubility in an alkali developer. The product has a repeating unit (B1) having a group represented by the following general formula (I), decomposes by the action of an acid, and increases in solubility in an alkaline developer ("(B) component") (Also called).

In general formula (I),
Rx ₁ and Rx ₂ each independently represents an alkyl group or a cycloalkyl group.
Rx ₃ represents a hydrogen atom, an alkyl group or a cycloalkyl group.
Ry represents an alkyl group or a cycloalkyl group.
At least two of Rx _{1 to} Rx ₃ and Ry may be bonded to form a ring structure.

In the general formula (I), the alkyl group in Rx ₁ , Rx ₂ , Rx ₃ and Ry is preferably an alkyl group having 1 to 15 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, a butyl group. Group, octyl group and the like. Preferably it is a C1-C4 alkyl group. The alkyl group in Rx ₁ , Rx ₂ , Rx ₃ and Ry may have a substituent such as a cycloalkyl group.
The cycloalkyl group in Rx ₁ , Rx ₂ , Rx ₃ and Ry is preferably a cycloalkyl group having 3 to 15 carbon atoms, such as a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, an adamantyl group, Examples thereof include polycyclic cycloalkyl groups such as a tricyclodecanyl group, a tetracyclododecanyl group, and a norbornyl group. The cycloalkyl group in Rx ₁ , Rx ₂ , Rx ₃ and Ry may have a substituent such as an alkyl group.
When Ry is a tertiary hydrocarbon group, Ry has a function of an acid-eliminable group, which is preferable. As the tertiary hydrocarbon group, t-butyl group, t-amyl group, 1-alkyl-1-cyclohexyl group, 1-alkyl-1-cyclopentyl group, 2-alkyl-2-adamantyl group, 2-adamantyl-2 Preferred examples include -propyl group and 2-cyclohexyl-2-propyl group.
Examples of the ring structure formed by combining at least two of Rx _{1 to} Rx ₃ and Ry include, for example, a monocyclic hydrocarbon structure such as a cyclopentane structure, a cyclohexane structure, a cycloheptane structure, an adamantane structure, and tricyclodecane. Examples thereof include polycyclic hydrocarbon structures such as a structure, a tetracyclododecane structure, and a norbornane structure.
A mode in which Rx ₃ and Ry are bonded to form a lactone structure is also preferable. The lactone structure to be formed is preferably a butyrolactone structure.

In the general formula (I), wherein the at least one of the Rx ₁ and Rx ₂ are either have a polycyclic hydrocarbon structure having 7 or more carbon atoms, Rx ₁ and Rx ₂ are bonded carbon atoms with 7 or more It is preferable to form a polycyclic hydrocarbon structure.
Rx ₁ or more and rx ₂ in carbon number 7 of polycyclic hydrocarbon structure and Rx ₁ and Rx ₂ are bonded form and having 7 or more carbon atoms which may have a polycyclic hydrocarbon structure, Preferably, it has 7 to 15 carbon atoms, and examples thereof include polycyclic cyclic hydrocarbon structures such as adamantane, norbornane, tricyclodecane, and tetracyclodecane.
The cycloalkyl group having 7 or more carbon atoms as Ry may be monocyclic or polycyclic and preferably has 7 to 15 carbon atoms. For example, adamantyl group, norbornyl group, tricyclodecanyl group, tetracyclo A decanyl group etc. are mentioned.

  The group represented by the general formula (I) has a tertiary ester structure and exhibits acid decomposability. Furthermore, since the alkoxycarbonyl group is substituted at the β-position, the acid reactivity is improved as compared with the unsubstituted tertiary ester structure.

  Preferred examples of the repeating unit (B1) having a group represented by the general formula (I) include a repeating unit represented by the following general formula (I-1a) or general formula (I-2a).

In general formulas (I-1a) and (I-2a),
Xa represents a hydrogen atom, an alkyl group (preferably a methyl group), a cyano group, a fluoroalkyl group (preferably a trifluoromethyl group) or a —CH ₂ —ORa ₅ group. Ra ₅ represents a hydrogen atom, an alkyl group, an acyl group, or a lactone group.
Ra _{2 to} Ra ₄ each independently represents a hydrogen atom, an alkyl group, a cyano group, or an alkoxycarbonyl group.
n represents 0 or 1.
Rx _{1 to} Rx ₃ and Ry have the same meanings as in general formula (I).

  The polymerizable compound corresponding to these repeating units is, for example, as shown below, a method in which a ketone compound and a halogen-substituted ester are reacted with zinc, or a ketone compound and an ester compound are reacted with a metal reagent such as LDA. It can be synthesized by synthesizing an alcohol form by a reaction method and reacting this with a carboxylic acid chloride.

  The content of the repeating unit (B1) having a group represented by the general formula (I) is preferably 1 to 60 mol%, more preferably 5 to 50 mol%, still more preferably 10 with respect to all repeating units in the polymer. -50 mol%.

  Specific examples of the repeating unit (B1) having a group represented by the general formula (I) are shown below, but the present invention is not limited thereto.

  The component (B) is a repeating unit having a group that can be further decomposed by an acid in addition to the repeating unit having an acid-decomposable group represented by the general formula (I) (hereinafter also referred to as “acid-decomposable group”). It is preferable to have. Among these, a resin having a group capable of decomposing with an acid in the side chain is more preferable.

A group preferable as a group that can be decomposed by an acid is a group in which a hydrogen atom of a —COOH group or —OH group is substituted with a group capable of leaving with an acid.
In the present invention, the acid-decomposable group is preferably an acetal group or a tertiary ester group.

  More preferably, it is a group in which a hydrogen atom of —COOH group or —OH group is substituted with a group capable of leaving with an acid represented by the following formulas (pI) to (pV).

In the general formulas (pI) to (pV),
R ₁₁ represents a linear or branched alkyl group.
Z represents an atomic group necessary for forming a cycloalkyl group together with a carbon atom.
R _{12 to} R ₁₆ each independently represents a linear or branched alkyl group or a cycloalkyl group. However, at least one of R _{12 to} R ₁₄ , or any of R ₁₅ and R ₁₆ is preferably a cycloalkyl group.
R _{17 to} R ₂₁ each independently represents a hydrogen atom, a linear or branched alkyl group or a cycloalkyl group. However, at least one of R _{17 to} R ₂₁ is preferably a cycloalkyl group. In addition, any one of R ₁₉ and R ₂₁ represents a linear or branched alkyl group or a cycloalkyl group.
R _{22 to} R ₂₅ each independently represents a hydrogen atom, a linear or branched alkyl group or a cycloalkyl group. However, at least one of R _{22 to} R ₂₅ is preferably a cycloalkyl group. R ₂₃ and R ₂₄ may be bonded to each other to form a ring.

In the general formulas (pI) to (pV), the alkyl group in R _{11 to} R ₂₅ is preferably a linear or branched alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, n -Propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group and the like can be mentioned.

The cycloalkyl group represented by R _{12 to} R ₂₅ or the cycloalkyl group formed by Z and the carbon atom may be monocyclic or polycyclic. Specific examples include groups having a monocyclo, bicyclo, tricyclo, tetracyclo structure or the like having 5 or more carbon atoms. The carbon number is preferably 6-30, and particularly preferably 7-25.

  Preferred cycloalkyl groups include adamantyl group, noradamantyl group, decalin residue, tricyclodecanyl group, tetracyclododecanyl group, norbornyl group, cedrol group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, A cyclodecanyl group and a cyclododecanyl group can be mentioned. More preferable examples include an adamantyl group, norbornyl group, cyclohexyl group, cyclopentyl group, tetracyclododecanyl group, and tricyclodecanyl group.

These alkyl groups and cycloalkyl groups may have a further substituent. As further substituents for alkyl groups and cycloalkyl groups, alkyl groups (1 to 4 carbon atoms), halogen atoms, hydroxyl groups, alkoxy groups (1 to 4 carbon atoms), carboxyl groups, alkoxycarbonyl groups (2 to 2 carbon atoms) 6). Examples of the substituent that the alkyl group, alkoxy group, alkoxycarbonyl group and the like may further have include a hydroxyl group, a halogen atom, and an alkoxy group.

  As the repeating unit having an alkali-soluble group protected by a structure represented by the general formulas (pI) to (pV), a repeating unit represented by the following general formula (pA) is preferable.

In the general formula (pA),
R represents a hydrogen atom, a halogen atom or a linear or branched alkyl group (preferably a linear or branched alkyl group having 1 to 4 carbon atoms). A plurality of R may be the same or different.
A represents a single bond, an alkylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a sulfonamide group, a urethane group, or a urea group, or a combination of two or more groups. Represents. A single bond and —COO—CH ₂ — are preferable.
Rp ₁ represents any one of the general formulas (pI) to (pV).

  The repeating unit represented by the general formula (pA) is particularly preferably a repeating unit composed of 2-alkyl-2-adamantyl (meth) acrylate and dialkyl (1-adamantyl) methyl (meth) acrylate.

  As for content of the repeating unit represented by general formula (pA), 1-60 mol% is preferable with respect to all the repeating units in a polymer, More preferably, it is 5-50 mol%, More preferably, it is 10-40 mol%.

  Hereinafter, although the specific example of the repeating unit shown by general formula (pA) is shown, this invention is not limited to this.

In specific examples, Rx represents H, CH ₃ , CF _3, or CH ₂ OH, and Rxa and Rxb each independently represents an alkyl group having 1 to 4 carbon atoms.

The component (B) preferably has a repeating unit having a lactone structure. The lactone structure may be any structure as long as it has a lactone structure, but is preferably a repeating unit having a 5- to 7-membered ring lactone structure, and a repeating unit having a cyclic hydrocarbon structure and a lactone structure. (B2) is more preferable. 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). Examples of the structure having a cyclic hydrocarbon structure and a lactone structure include structures represented by general formulas (LC1-3) to (LC1-16). Further, a group having a lactone structure may be directly bonded to the main chain. Preferable lactone structures are (LC1-1), (LC1-4), (LC1-5), (LC1-13), and (LC1-14).

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. n2 represents an integer of 0 to 4. When n2 is 2 or more, a plurality of substituents (Rb ₂ ) may be the same or different, and a plurality of substituents (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),
Rb ₀ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms. Preferred substituents that the alkyl group represented by Rb ₀ may have include a hydroxyl group and a halogen atom.
Examples of the halogen atom for Rb ₀ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Rb ₀ is preferably a hydrogen atom or a methyl group.
Ab represents 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 group obtained by combining these. To express.
A linking group represented by a single bond or —Ab ₁ —CO ₂ — is preferable. Ab ₁ is a linear or branched alkylene group, a monocyclic or polycyclic cycloalkylene group, and 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.

The content of the repeating unit having a lactone structure (including a repeating unit having a cyclic hydrocarbon structure and a lactone structure) is preferably from 15 to 60 mol%, more preferably from 20 to 50 mol, based on all repeating units in the polymer. %, More preferably 30 to 50 mol%.
The content of the repeating unit having a cyclic hydrocarbon structure and 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. It is.

  Specific examples of the repeating unit having a preferred lactone structure include the following repeating units, but the present invention is not limited thereto.

  The component (B) preferably has a repeating unit (B3) having a hydroxyl group and / or a repeating unit (B4) having a cyano group. This improves the substrate adhesion and developer compatibility. The repeating unit (B3) having a hydroxyl group is more preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group. The repeating unit (B4) having a cyano group is more preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a cyano group. Here, the alicyclic hydrocarbon structure 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, groups 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 rest are hydrogen atoms. In general formula (VIIa), it is more preferable that two members out of R _{2c to} R _4c are hydroxyl groups and the remaining 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 the 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) ~ (VIIc), same meanings as R _2c to R _4c.

  The content of the repeating unit having a hydroxyl group or a cyano group is preferably from 5 to 40 mol%, more preferably from 5 to 30 mol%, still more preferably from 10 to 25 mol%, based on all repeating units in the polymer.

  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) may have a repeating unit represented by the following general formula (VIII).

In general formula (VIII):
Z ₂ represents —O— or —N (R ₄₁ ) —. R ₄₁ represents a hydrogen atom, a hydroxyl group, an alkyl group, or —OSO ₂ —R ₄₂ . R ₄₂ represents an alkyl group, a cycloalkyl group or a camphor residue. The alkyl group of R ₄₁ and R ₄₂ may be substituted with a halogen atom (preferably a fluorine atom) or the like.

Examples of the repeating unit represented by the general formula (VIII) include the following specific examples.
The present invention is not limited to these.

  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 in which the α-position is substituted with an electron-withdrawing group (preferably a structure represented by the following general formula (F1) 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. R _{50 to} R ₅₅ are preferably all 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. 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.

  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 1-adamantyl (meth) acrylate, tricyclodecanyl (meth) acrylate, and cyclohexyl (meth) acrylate.

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 contained.

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

  (B) As a component, Preferably, all the repeating units are comprised by the (meth) acrylate type repeating unit. In this case, all of the repeating units can be used as methacrylate repeating units, all of the repeating units can be used as acrylate repeating units, and a mixture of methacrylate repeating units / acrylate repeating units. It is preferable that it is 50 mol% or less of all repeating units.

More preferably 1 to 50 mol% of the repeating unit having a group represented by the general formula (I), and a repeating unit having another acid-decomposable group (preferably the following general formulas (ARA-1) to (ARA-5) Having a lactone structure represented by the following general formulas (ARL-1) to (ARL-7), preferably 20 to 50 mol%, a repeating unit having a lactone structure (Repeating unit) 20 to 50 mol%, a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group (preferably a hydroxyl group or cyano represented by the following general formulas (ARH-1) to (ARH-3)) A repeating unit having an alicyclic hydrocarbon structure substituted with a group) a copolymer having 5 to 30 mol%, or further having another repeating unit of 0 to 20 mol% It is a polymerization polymer.
(In the formula, Rxy ₁ represents a hydrogen atom or a methyl group, and Rxa ₁ and Rxb ₁ represent a methyl group or an ethyl group.)

  When the positive photosensitive composition of the present invention is used for an upper resist of a multilayer resist, the component (B) contains silicon atoms in addition to the repeating unit (B1) having a group represented by the general formula (I). It is preferable to have.

As the resin having a silicon atom and decomposing by the action of an acid to increase the solubility in an alkaline developer, a resin having a silicon atom in at least one of a main chain and a side chain can be used. Examples of the resin having a siloxane structure in the side chain of the resin include a repeating unit (B1) having a group represented by the general formula (I), an olefin monomer having a silicon atom in the side chain, maleic anhydride and an acid. Mention may be made of copolymers of (meth) acrylic acid monomers having degradable groups in the side chain.
The resin having a silicon atom is preferably a resin having a trialkylsilyl structure or a monocyclic or polycyclic siloxane structure, and has a structure represented by the following general formulas (SS-1) to (SS-4). A resin having a unit is more preferable, and has a (meth) acrylate-based repeating unit, a vinyl-based repeating unit, or an allyl-based repeating unit having a structure represented by General Formulas (SS-1) to (SS-4). It is more preferable.

  In general formulas (SS-1) to (SS-4), Rs represents an alkyl group having 1 to 5 carbon atoms, preferably a methyl group or an ethyl group.

The resin having a silicon atom preferably has a repeating unit having two or more different types of silicon atoms, more preferably (Sa) a repeating unit having 1 to 4 silicon atoms and (Sb) 5 to 10 silicon atoms. A resin having both of the repeating units, and more preferably, at least one repeating unit having a structure represented by formulas (SS-1) to (SS-3) and formula (SS-4). It is resin which has a repeating unit which has the structure represented by these.

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 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 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 positive photosensitive 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. 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, and particularly preferably 5,000 to 15,5,000 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 (Mw / Mn) is usually 1 to 5, preferably 1 to 2, more preferably 1.3 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) according to the present invention in the entire positive photosensitive composition is preferably from 60 to 99 mass%, more preferably from 80 to 99 mass% based on the total solid content. It is 98 mass%.
In the present invention, the 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. 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 containing a group capable of decomposing by the action of an acid to release an alkali-soluble group or a hydrophilic group is preferable. The group capable of decomposing by the action of an acid to release an alkali-soluble group or a hydrophilic group is preferably a group in which a carboxyl group or a hydroxyl group is protected with an acid-eliminable group. In order not to lower the transmittance of 220 nm or less as the dissolution controlling compound, when a compound having no aromatic ring is used or a compound having an aromatic ring is used, the compound having an aromatic ring is used as a positive photosensitive composition. It is preferable to use it in an addition amount of 20 wt% or less based on the solid content.
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 in which the carboxylic acid is protected with an acid leaving group, such as saccharides. A polyol or a compound in which a hydroxyl group thereof is protected with an acid leaving 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. Preferable nitrogen-containing basic compound structures 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 group (preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (preferably having 6 carbon atoms). ~ 20). R ²⁵⁰ and R ²⁵¹ may combine with each other to form a ring. These may have a substituent, and as the alkyl group and cycloalkyl group having a substituent, an aminoalkyl group (preferably having a carbon number of 1 to 20) or an aminocycloalkyl group (preferably having a carbon number of 3 to 3). 20), a hydroxyalkyl group (preferably having 1 to 20 carbon atoms) or a hydroxycycloalkyl group (preferably having 3 to 20 carbon atoms) is preferable.
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. Further preferable compounds include an imidazole structure, a diazabicyclo structure, an onium hydroxide structure, an onium carboxylate structure, an alkylamine structure (preferably an alkylamine derivative having a hydroxyl group and / or an ether bond), an aniline structure (preferably a hydroxyl group and / or an ether). An aniline derivative having a bond) or a compound having a pyridine structure.

Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, benzimidazole, and 2-phenylbenzimidazole. 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. As a compound which has an onium carboxylate structure, the anion part of the compound which has an onium hydroxide structure turns into a carboxylate, For example, an acetate, an adamantane-1-carboxylate, a perfluoroalkyl carboxylate etc. are mention | raise | lifted. Examples of the compound having an alkylamine structure include tri (n-butyl) amine, tri (n-octyl) amine, ethanolamine, diethanolamine, triethanolamine, and tris (methoxyethoxyethyl) amine. Examples of the aniline compound include 2,6-diisopropylaniline, N, N-dibutylaniline, N, N-bis (hydroxyethyl) aniline and the like.

  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-based surfactant The positive photosensitive composition of the present invention further comprises a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant and silicon-based surfactant, fluorine atom and silicon atom It is preferable to contain any one of these, or two or more of them.

  When the positive photosensitive composition of the present invention contains fluorine and / or a silicon-based surfactant, adhesion and development with good sensitivity and resolution when using an exposure light source of 250 nm or less, particularly 220 nm or less. A resist pattern with few defects can be provided.

Examples of commercially available surfactants that can be used include F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189, 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.), Poly Fluorosurfactants or silicon surfactants such as siloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can be mentioned.

  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.

  Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.).

  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 appropriately adjusted and used so that the receding contact angle of the resist film is 60 ° to 80 °, but is preferably 0.1 to the total amount of the positive photosensitive composition (excluding the solvent). 5% by mass.

Organic Solvent The positive photosensitive composition of the present invention is used by dissolving the above components in a predetermined organic solvent.
Examples of the organic solvent 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 -Dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofuran, etc.

In the present invention, the organic solvent may be used alone or in combination, but it is preferable to use a mixed solvent containing two or more 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 containing at least a solvent having a hydroxyl group and a solvent not having a hydroxyl group (preferred mixing ratio (mass) is 1/99 to 99/1, more preferably 10/90 to 90/10, More preferably, it is 20/80 to 60/40, and a mixed solvent containing 50% by mass or more of a solvent having no hydroxyl group is particularly preferred from the viewpoint of coating uniformity.
(S2) A mixed solvent containing at least a solvent having an ester structure and a solvent having a ketone structure (preferred mixing ratio (mass) is 1/99 to 99/1, more preferably 10/90 to 90/10, The mixed solvent containing 50% by mass or more of the solvent having an ester structure is particularly preferable in terms of coating uniformity.
(S3) A mixed solvent containing at least a solvent having an ester structure and a solvent having a lactone structure (preferred mixing ratio (mass) is 70/30 to 99/1, more 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 in terms of stability over time).
(S4) A mixed solvent containing at least a solvent having an ester structure, a solvent having a lactone structure, and a solvent having a hydroxyl group (preferable mixing ratio (mass) is 30 to 80% by mass of the solvent having an ester structure, 1 to 20% by mass of the solvent having a solvent and 10 to 60% by mass of a solvent having a hydroxyl group).
(S5) A mixed solvent containing at least a solvent having an ester structure, a solvent having a carbonate structure, and a solvent having a hydroxyl group (preferable mixing ratio (mass) is 30 to 80% by mass of the solvent having an ester structure, and the carbonate structure. 1 to 20% by mass of the solvent having a solvent and 10 to 60% by mass of a solvent having 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 (preferable mixing ratio (mass) is 30 to 80% by mass of the solvent having an ester structure, the ketone structure 10 to 60% by mass of a solvent having a lactone and 1 to 20% by mass of 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 having 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. Propylene glycol monomethyl ether and ethyl lactate are more preferable.
Examples of the solvent having no hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide. Of these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are more preferable, and propylene glycol monomethyl ether acetate, ethyl ethoxypropio Nate, 2-heptanone and cyclohexanone are even more 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, and propylene carbonate is preferred.

<Other additives>
If necessary, the positive photosensitive composition of the present invention may further contain a dye, a plasticizer, a surfactant other than the fluorine-based and / or silicon-based surfactant, and a photosensitizer. it can.
Specific examples of surfactants other than fluorine and / or silicon surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene / polyoxypropylene block copolymers And nonionic surfactants such as sorbitan aliphatic esters and polyoxyethylene sorbitan aliphatic esters.

(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 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 formed on a substrate (for example, silicon / silicon dioxide coating) used for manufacturing a precision integrated circuit element by an appropriate coating method such as a spinner or a coater to have an arbitrary thickness (usually 50 to 500 nm). 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), EUV (13 nm), X-ray, electron beam, etc. ArF excimer laser, F ₂ excimer laser , EUV (13 nm) and electron beam are preferable.

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.

Examples of the alkaline developer of the positive photosensitive composition include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia and other inorganic alkalis, ethylamine, n-propylamine and the like. Secondary amines such as amines, diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxy Alkaline aqueous solutions such as quaternary ammonium salts such as pyrrole and 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 alkaline developer is usually from 10.0 to 14.0.

The positive photosensitive 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 with radiation 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.

Synthesis Example 1 (Synthesis of (monomer-A))
Under a nitrogen atmosphere, 13.0 g (0.20 mol) of zinc and 150 ml of toluene were mixed, and a mixed solution of 10.0 g (0.067 mol) of 2-adamantanone and 30.6 g (0.20 mol) of methyl bromoacetate was exothermic. Was added in small portions until the start. The remaining solution was slowly added so as to maintain reflux, and when the exotherm subsided, the mixture was heated to 100 ° C. and reacted for 1 hour. The reaction solution was cooled to 0 ° C., and 200 ml of 10% sulfuric acid aqueous solution was slowly added thereto. The reaction solution was extracted with ethyl acetate, and the organic phase was washed with water, dried and concentrated to obtain a crude product. When this was purified by column chromatography, 13.7 g of 2-methoxycarbonylmethyl-2-adamantanol was obtained.
10.0 g (47.6 mmol) of the obtained alcohol was dissolved in 100 ml of THF, and 9.6 g (95.1 mmol) of triethylamine and 0.1 g of 4-dimethylaminopyridine were added thereto. To this solution, 7.5 g (71.4 mmol) of methacrylic acid chloride was slowly added dropwise and reacted at room temperature for 10 hours. The reaction solution was weakly acidified with 10% aqueous hydrochloric acid, extracted with ethyl acetate, and the organic phase was washed with water, dried and concentrated to obtain a crude product. When this was purified by column chromatography, 6.2 g of the following monomer-A was obtained.

Synthesis Example 2 (Synthesis of (monomer-B))
Under a nitrogen atmosphere, 23.7 ml (47.3 mmol) of 2M-lithium diisopropylamide was added to 100 ml of dry THF, and the solution was cooled to -78 ° C. To this was added dropwise 5 g (43.0 mmol) of tert-butyl acetate over 30 minutes. After stirring for 30 minutes, a THF solution of 6.46 g (43.0 mmol) of 2-adamantanone was added dropwise thereto over 30 minutes. The mixture was allowed to warm to room temperature and stirred for 1 hour, and then the reaction solution was cooled to 0 ° C., and 6.74 g (64.5 mmol) of methacrylic acid chloride was added dropwise thereto over 30 minutes. After reacting at room temperature for 10 hours, 100 ml of water was slowly added. The reaction solution was extracted with ethyl acetate, and the organic phase was washed with water, dried and concentrated to obtain a crude product. When this was purified by column chromatography, 4.3 g of the following monomer-B was obtained.

Synthesis Example 3 (Synthesis of Resin (RA-1))
Under a nitrogen stream, 4.4 g of cyclohexanone was placed in a three-necked flask and heated to 80 ° C. Monomer-A (5.85 g), gamma butyrolactone methacrylate (5.1 g), and a polymerization initiator V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) in 10 mol% with respect to the monomer were dissolved in cyclohexanone (39.4 g) over 6 hours. . After completion of dropping, the reaction was further carried out at 80 ° C. for 2 hours. The reaction mixture was allowed to cool and then added dropwise over 20 minutes to a mixed solution of 350 m of heptane / 150 ml of ethyl acetate. The precipitated powder was collected by filtration and dried to obtain 8.3 g of resin (RA-1). The weight average molecular weight of the obtained resin (RA-1) was 7600 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.67.

  Resins (RA-2) to (RA-7) and comparative resin (RX) were synthesized in the same manner. The weight average molecular weight was adjusted by changing the amount of the initiator.

  Hereinafter, the structures of resins (RA-1) to (RA-7) and resin (RX) are shown.

Examples 1-8 and Comparative Example 1
<Resist preparation>
The components shown in Table 1 below 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 micron 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 1>
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.
The resist film was exposed with an ArF excimer laser stepper (NA = 0.75, dipole manufactured by ASML) 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 When the exposure amount that reproduces a mask pattern of 75 nm line and space 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, 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.

Hereinafter, abbreviations in the table are shown.
[Acid generator]

[Basic compounds]
TPSA: triphenylsulfonium acetate DIA: 2,6-diisopropylaniline TEA: triethanolamine 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.) (silicon-based)
〔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 1, it is clear that the positive photosensitive composition of the present invention is excellent in pattern collapse performance.

Immersion exposure <Resist preparation>
0.2 g of the following surface hydrophobized resin (Polymer-A) is further added to the components of Examples 1 to 8 and Comparative Example 1 shown in Table 1, and dissolved in a solvent to obtain a solution having a solid content concentration of 5% by mass. The positive resist solution was prepared by filtering through a 0.03 μm polyethylene filter. The prepared positive resist solution was evaluated by the following method. In addition, the receding contact angle of pure water of the resist film was 65 to 75 ° when a positive resist solution was applied by a spin coater and dried at 120 ° C. for 60 seconds to form a 160 nm resist film.
<Resist evaluation 2>
Except for using an ArF excimer laser immersion scanner (NA = 0.85) and performing immersion exposure using ultrapure water as the immersion liquid, the pattern collapse performance is achieved using the same method as in resist evaluation 1. evaluated. The evaluation results are shown in Table 1.

  From Table 1, it is clear that the positive photosensitive composition of the present invention is excellent in pattern collapse performance even in immersion exposure.

Claims (6)

(A) a compound that generates an acid upon irradiation with actinic rays or radiation, and (B) a repeating unit (B1) having a group represented by the following general formula (I), decomposed by the action of an acid, and subjected to alkali development A positive photosensitive composition comprising a resin having increased solubility in a liquid.

In general formula (I),
Rx ₁ and Rx ₂ each independently represents an alkyl group or a cycloalkyl group.
Rx ₃ represents a hydrogen atom, an alkyl group or a cycloalkyl group.
Ry represents an alkyl group or a cycloalkyl group.
At least two of Rx _{1 to} Rx ₃ and Ry may be bonded to form a ring structure. In the general formula (I), wherein the at least one of the Rx ₁ and Rx ₂ are either have a polycyclic hydrocarbon structure having 7 or more carbon atoms, Rx ₁ and Rx ₂ are bonded carbon atoms with 7 or more The positive photosensitive composition according to claim 1, wherein the polycyclic hydrocarbon structure is formed.   3. The positive photosensitive composition according to claim 1, wherein Ry in the general formula (I) is a cycloalkyl group having 7 or more carbon atoms. The positive photosensitive composition according to any one of claims 1 to 3, wherein the component (B) further has at least one type of repeating unit selected from the following (B2) to (B4).
(B2) a repeating unit having a cyclic hydrocarbon structure and a lactone structure,
(B3) a repeating unit having a hydroxyl group and (B4) a repeating unit having a cyano group. The component (A) contains at least one compound capable of generating an acid selected from the following (a) to (c) upon irradiation with actinic rays or radiation. The positive photosensitive composition as described.
(A) a fluorine-substituted alkanesulfonic acid having 2 or more carbon atoms,
(B) Bis (alkylsulfonyl) imidic acid and (c) Aromatic sulfonic acid substituted with a fluorine atom or a group having a fluorine atom.   A pattern forming method comprising a step of forming a photosensitive film from the positive photosensitive composition according to claim 1, and exposing and developing the photosensitive film.