JP2007072102A - Positive photosensitive composition and pattern forming method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive photosensitive composition excellent in density distribution dependency even in formation of a fine pattern of ≤100 nm, and a pattern forming method using the same. <P>SOLUTION: The positive photosensitive composition contains (A) a compound capable of generating an acid upon irradiation with an actinic ray or radiation and (B) a resin having a group which is decomposed by the action of an acid to increase solubility in an alkali developer, wherein (B) the resin component is a resin having a repeating unit (Ba) having a diamantane structure and a repeating unit (Bb) having a group which is decomposed by the action of an acid to increase solubility in an alkali developer and having a non-polycyclic hydrocarbon structure within a group which is released by the action of an acid from the group which is decomposed by the action of an acid to increase solubility in an alkali developer. The pattern forming method using the same is also provided. <P>COPYRIGHT: (C)2007,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 actinic rays or radiation such as far ultraviolet rays, and develops the irradiated portion and non-irradiated portion of the active ray or radiation by a reaction using this acid as a catalyst. It is a pattern forming material that changes the solubility in a liquid 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. JP-A-9-73173 (Patent Document 1) describes a resist composition containing an acid-decomposable resin having an adamantane structure. However, as the pattern becomes finer, it is necessary to reduce the thickness of the resist film, and the dry etching resistance of the resist film is required. US Patent Application Publication No. 2005 / 0074690A (Patent Document 2) describes a resin having a repeating unit having a diamantane structure. However, dry etching resistance correlates with the carbon density of the resin and can be improved by increasing the carbon density, but it is extremely difficult to achieve compatibility with image resolution performance, and in particular, a fine pattern with a line width of 100 nm or less is required. When forming, it is necessary to select not only the structure of the repeating units but also the optimal combination of repeating units.
Especially in devices where different patterns such as dense line and space pattern and isolated line pattern are mixed, there is a problem of density dependency that the isolated pattern becomes thin because the optical image is different even if a mask with the same line width is used, There is a need for improvement.

JP-A-9-73173 US Patent Application Publication No. 2005 / 0074690A

  Accordingly, an object of the present invention is to provide a positive photosensitive composition excellent in density dependency 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) Positive photosensitivity containing a compound that generates an acid upon irradiation with actinic rays or radiation, and (B) a resin having a group that decomposes by the action of the acid and increases the solubility in an alkaline developer. A composition comprising:
The resin of component (B) has a repeating unit (Ba) having a diamantane structure and a group that decomposes by the action of an acid and increases the solubility in an alkali developer, and decomposes by the action of the acid, A positive photosensitive resin characterized in that it is a resin having a repeating unit (Bb) having a non-polycyclic hydrocarbon structure in a group that is eliminated by the action of an acid of a group that increases the solubility in a developer. Composition.

  (2) A group having a group that decomposes by the action of an acid and increases the solubility in an alkali developer, and that decomposes by the action of the acid and increases the solubility in an alkali developer. The repeating unit (Bb) having a non-polycyclic hydrocarbon structure in the group to be separated is at least one type of repeating unit selected from the following general formulas (Bb-1a), (Bb-1b) and (Bb-2a) The positive photosensitive composition as described in (1), wherein

In the general formula (Bb-1a),
Rx represents a hydrogen atom or an alkyl group.
Rb ₁ represents a monocyclic hydrocarbon group represented by the following general formula (Bb-1a-1).
Rb ₂ and Rb ₃ each independently represent an alkyl group, a monocyclic cyclic hydrocarbon group represented by the general formula (Bb-1a-1), or an allyl group. Rb ₂ and Rb ₃ may combine with each other to form a monocyclic hydrocarbon structure.

In the general formula (Bb-1a-1),
n represents an integer of 1 to 4.

In general formulas (Bb-1b) and (Bb-2a),
Rx represents a hydrogen atom or an alkyl group.
Ra ₁ represents an alkyl group or an allyl group.
n represents an integer of 1 to 4.
Ra ₁ ′, Ra ₂ ′ and Ra ₃ ′ each independently represents an alkyl group.

  (3) The repeating unit (Ba) having a diamantane structure is a repeating unit having a diamantane structure and not affected by the action of an acid or an alkali. (1) or (2) A positive photosensitive composition.

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

  (5) A pattern formation comprising a step of forming a photosensitive film from the positive photosensitive composition according to any one of (1) to (4), and exposing and developing the photosensitive film. Method.

  According to the present invention, it is possible to provide a positive photosensitive composition excellent in density dependency 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 comprises a compound that generates acid upon irradiation with actinic ray or radiation (hereinafter also referred to as “acid generator”). Contain).
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 actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, such as US Pat. No. 3,849,137, German Patent No. 3914407, JP-A 63-26653, JP-A 55-164824, JP-A 62-69263, JP-A 63-146038, JP-A 63-163452, JP-A 62-153853, JP-A The compounds described in 63-146029 and the like 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. An organic anion having a carbon atom is preferable.

  Preferable organic anions include organic anions represented by the following general formula.

In the above general formula:
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, a cycloalkyl 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) - can be exemplified linked group a linking group such as.
Rd ₁ represents a hydrogen atom or an alkyl group.
Rc ₃ , Rc ₄ and Rc ₅ each independently represents an organic group.
Examples of the organic group of Rc ₃ , Rc _4, and Rc ₅ include the same organic groups as those preferred for Rc ₁ , and preferably a perfluoroalkyl group having 1 to 4 carbon atoms.
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, a cycloalkylene group, and an arylene group. Preferably, it is a C2-C4 perfluoroalkylene group.
The organic group of Rc ₁ and Rc _{3 to} Rc ₅ is 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. Further, Rc ₃ and Rc ₄ are preferably bonded to form a ring, whereby 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.

  Preferred examples of the (ZI) component 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 a part of R _{201 to} R ₂₀₃ may be an aryl group, and the rest may be an alkyl group or a cycloalkyl group.
Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, aryldialkylsulfonium compounds, diarylcycloalkylsulfonium compounds, aryldicycloalkylsulfonium compounds, and the like.

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, and 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 has 1 to 15 carbon atoms.
The linear or branched alkyl group is preferably, for example, methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group, t-butyl group and the like.
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, more preferably , An alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. 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 having no aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.

The aromatic ring-free organic group 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, an alkoxycarbonylmethyl group, Even more preferred is a linear, branched 2-oxoalkyl group.

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

  The compound (ZI-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 , R _6c and R _7c, 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 or an amide bond may be included. Examples of the group formed by combining any two or more of R _{1c to} R _5c , R _6c and R _7c , and R _x and R _y include a butylene group and a pentylene group.
Zc ^- represents a non-nucleophilic anion, in the general formula (ZI) X ^- is similar to the non-nucleophilic anion.

The alkyl group as R _{1c to} R _7c may be either linear or branched, and for example, a linear or branched alkyl group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms (for example, 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 straight chain, branched alkyl group, cycloalkyl group, or a straight chain, branched, or cyclic alkoxy group, and more preferably the sum of the carbon number of R _{1c to} R _5c is 2 ~ 15. Thereby, solvent solubility improves more and generation | occurrence | production of a particle is suppressed at the time of a preservation | save.

_Examples of the alkyl group as R _x and R _y include the same alkyl groups as R _{1c to} R _7c . The alkyl group as R _x and R _y is more preferably a linear or branched 2-oxoalkyl group or an alkoxycarbonylmethyl group.
The cycloalkyl group as R _x and R _y may be the same as the cycloalkyl group as R _1c to R _7c. The cycloalkyl group as R _x and R _y is more preferably a cyclic 2-oxoalkyl group.
Examples of the linear, branched, 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.
Aryl group R ₂₀₄ to R ₂₀₇ are aryl groups, such as naphthyl group, a heteroaryl group such as pyrrole residue more preferably a phenyl group or an indole residue.
The alkyl group represented by R _{204 to} R ₂₀₇ may be either linear or branched, and is preferably a linear or branched alkyl group having 1 to 10 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, Butyl group, pentyl group).
Cycloalkyl groups R ₂₀₄ to R ₂₀₇ is preferably, and a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, norbornyl).
The R ₂₀₄ to R ₂₀₇ are substituents which may have, for example, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (e.g., 6 carbon atoms 15), alkoxy groups (for example, having 1 to 15 carbon atoms), halogen atoms, hydroxyl groups, phenylthio groups and the like.
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 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 _207a and R ₂₀₈ each independently represents an alkyl group, a cycloalkyl group, an aryl group, or an electron-withdrawing group. R _207a 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, compounds represented by general formulas (ZI) to (ZIII) are more preferable.

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

[2] (B) a repeating unit (Ba) having a diamantane structure and a group that decomposes by the action of an acid and increases the solubility in an alkali developer, and decomposes by the action of the acid; Resin having a repeating unit (Bb) having a non-polycyclic hydrocarbon structure in a group that is eliminated by the action of an acid of a group that increases the solubility in the resin. The positive photosensitive composition of the present invention has a diamantane structure. A repeating unit (Ba) having a group which decomposes by the action of an acid and increases the solubility in an alkaline developer, and which decomposes by the action of the acid and increases the solubility in an alkaline developer And a resin having a repeating unit (Bb) having a non-polycyclic hydrocarbon structure in a group leaving by the action of an acid (also referred to as “resin of component (B)”).

The component (B) resin is a resin having at least one group that decomposes under the action of an acid and increases the solubility in an alkaline developer (hereinafter also referred to as “acid-decomposable group”). The acid-decomposable group may be contained in the repeating unit (Ba) having a diamantane structure or may be contained in another repeating unit.
Examples of the acid-decomposable group include a group in which a hydrogen atom of an alkali-soluble group such as a carboxyl group or a hydroxyl group is protected with a group capable of leaving by the action of an acid.
Examples of the group capable of leaving by the action of an acid include —C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ), —C (R ₀₁ ) ( R ₀₂ ) (OR ₃₉ ) and the like.
In the formula, R _{36 to} R ₃₉ each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R ₃₆ and R ₃₇ may be bonded to each other to form a ring.
R _{01 and} R ₀₂ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group.

(Ba) Repeating unit having a diamantane structure The repeating unit (Ba) having a diamantane structure is preferably a repeating unit selected from the following.
(Ba-1) A repeating unit having an acid-decomposable group and having a diamantane structure in a group that is eliminated by the action of an acid of the acid-decomposable group.
(Ba-2) A repeating unit having a diamantane structure and not affected by the action of acid or alkali.
The repeating unit (Ba-1) or (Ba-2) may have a substituent, and preferred examples of the substituent include an alkyl group and a polar functional group. The repeating unit (Ba-1) or (Ba-2) is preferably a repeating unit having a structure in which a polar functional group is substituted on diamantane. Examples of the polar functional group include a hydroxyl group, a carboxyl group, a cyano group, an amide group, a sulfonamide group, and a sulfonylimide group, and preferably a hydroxyl group.

(Ba-1) a repeating unit having a diamantane structure in a group having an acid-decomposable group and leaving by the action of an acid of the acid-decomposable group, having a diamantane structure and leaving by an action of an acid The groups represented by the following general formulas (DpI) to (DpV) are preferable, having an acid-decomposable group, and a repeating unit having a diamantane structure in a group that is eliminated by the action of an acid of the acid-decomposable group. Is preferably a repeating unit having an acid-decomposable group in which a hydrogen atom of an alkali-soluble group is protected by a group represented by the general formulas (DpI) to (DpV).

In general formulas (DpI) to (DpV),
Rd ₁₁ represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or a sec-butyl group, and Z represents an atomic group necessary for forming a diamantyl group together with a carbon atom. Represents.
Rd _{12 to} Rd ₁₆ each independently represents a linear or branched alkyl group or cycloalkyl group having 1 to 4 carbon atoms. However, at least one of Rd _{12 to} Rd ₁₄ , or any of Rd ₁₅ and Rd ₁₆ represents a diamantyl group or a group having a diamantyl group (preferably a C 1-5 alkyl group having a diamantyl group).
Rd _{17 to} Rd ₂₁ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a cycloalkyl group, provided that at least one of Rd _{17 to} Rd ₂₁ is diamantyl. Or a group having a diamantyl group (preferably an alkyl group having 1 to 5 carbon atoms having a diamantyl group). Further, either Rd ₁₉ or Rd ₂₁ represents a linear or branched alkyl group or cycloalkyl group having 1 to 4 carbon atoms.
Rd _{22 to} Rd ₂₅ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a cycloalkyl group, provided that at least one of Rd _{22 to} Rd ₂₅ is diamantyl. Or a group having a diamantyl group (preferably an alkyl group having 1 to 5 carbon atoms having a diamantyl group). Rd ₂₃ and Rd ₂₄ may be bonded to each other to form a ring.

  As the repeating unit having an acid-decomposable group in which the hydrogen atom of the alkali-soluble group is protected by a group represented by the general formulas (DpI) to (DpV), a repeating unit represented by the following general formula (DpA) is preferable.

In general formula (DpA),
R represents a hydrogen atom, a halogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. The alkyl group of R may be substituted with a halogen atom, a hydroxyl group or the like. 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. To express. A single bond is preferable.
Rp1 represents any group of the above general formulas (DpI) to (DpV).

  Preferred specific examples of the repeating unit (Ba-1) are shown below, but the present invention is not limited thereto.

In the above example,
Rx represents a hydrogen atom or an alkyl group. Rx is preferably a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.
Rxa and Rxb each independently represent a linear or branched alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, and a hetero atom such as oxygen or sulfur in the alkyl chain or cycloalkyl chain May be included.

(Ba-2) Repeating unit having a diamantane structure and not affected by the action of an acid or an alkali In the present invention, “not affected by the action of an acid or an alkali” means the positive photosensitive film of the present invention. The photosensitive composition is non-reactive or very small with respect to the action of acid or alkali in a commonly used process, and has substantially a group that contributes to image formation by the action of acid or alkali. It is not. For example, in the case of a positive chemically amplified resist, an acid generator is decomposed at an exposed portion in an exposure process, and an acid is generated. In the post-heating step, the acid decomposes the resin having an acid-decomposable group and releases an alkali-soluble group, whereby only the exposed portion can be developed with an alkali, and the exposed portion is selectively developed in the alkaline development step to form a pattern. . The repeating unit (Ba-2) has a group that has no or very little reactivity to the action of acid and alkali in the exposure, post-heating step or development step and substantially contributes to a change in dissolution contrast. No.

  The repeating unit (Ba-2) is preferably represented by the following general formula (DPB).

In the general formula (DPB),
Rx represents a hydrogen atom or an alkyl group. Rx is preferably a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.
Rp ₂ is a group having a diamantyl group or a diamantyl group (preferably an alkyl group having 1 to 5 carbon atoms having a diamantyl group) A represents a desorbed no group from the oxygen atom by the action of an acid or alkali. Examples of the group that does not leave the oxygen atom by the action of an acid or alkali include a group formed by a primary or secondary ester bond. Further, as shown below (D2-1), (D2-2), (D2-5) to (D2-14), tertiary carbon atoms at the 1st, 4th, 6th and 9th positions of the diamantyl group A tertiary ester structure linked with an ester bond also does not exhibit acid decomposability, does not substantially contribute to image formation by the action of an acid, and can be given as a preferred structure.

  Although the preferable specific example of a repeating unit (Ba-2) is shown below, this invention is not limited to this.

  In the above specific examples, Rx represents a hydrogen atom or an alkyl group. Rx is preferably a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.

(Bb) A repeating unit having an acid-decomposable group and having a non-polycyclic hydrocarbon structure in a group that is eliminated by the action of an acid of the acid-decomposable group. It is a hydrocarbon structure not including a cyclic hydrocarbon structure, and is preferably constituted by a monocyclic cyclic hydrocarbon structure and / or a chain hydrocarbon structure.
The repeating unit (Bb) having an acid-decomposable group and having a non-polycyclic hydrocarbon structure in the group that is eliminated by the action of an acid of the acid-decomposable group has an acid-decomposable group, The acid-decomposable group has a repeating unit (Bb-1) having a monocyclic cyclic hydrocarbon structure in the group that is eliminated by the action of an acid, and the acid-decomposable group has an acid action. The repeating unit (Bb-2) having an acyclic hydrocarbon structure in the group eliminated by the above is preferable.

(Bb-1) a repeating unit having an acid-decomposable group and having a monocyclic cyclic hydrocarbon structure in a group which is eliminated by the action of an acid of the acid-decomposable group In the repeating unit (Bb-1) As the monocyclic hydrocarbon structure, a monocyclic hydrocarbon structure having 4 to 10 carbon atoms is preferable, specifically, cyclobutyl structure, cyclopentyl structure, cyclohexyl structure, cycloheptyl structure, cyclooctyl structure, cyclononyl structure. And a cyclodecyl structure, more preferably a cyclopentyl structure and a cyclohexyl structure.

  The repeating unit (Bb-1) is preferably a repeating unit represented by the following general formula (Bb-1a) or (Bb-1b).

In the general formula (Bb-1a),
Rx represents a hydrogen atom or an alkyl group.
Rb ₁ represents a monocyclic hydrocarbon group represented by the following general formula (Bb-1a-1).
Rb ₂ and Rb ₃ each independently represent an alkyl group, a monocyclic cyclic hydrocarbon group represented by the general formula (Bb-1a-1), or an allyl group. Rb ₂ and Rb ₃ may combine with each other to form a monocyclic hydrocarbon structure.

In the general formula (Bb-1a-1),
n represents an integer of 1 to 4.

In the general formula (Bb-1b),
Rx represents a hydrogen atom or an alkyl group.
Ra ₁ represents an alkyl group or an allyl group.
n represents an integer of 1 to 4.

In general formulas (Bb-1a) and (Bb-1b), the alkyl group of Rx is preferably an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and the like. Can be mentioned. The alkyl group of Rx may be substituted with a fluorine atom, a hydroxyl group or the like. Rx is preferably a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.
Alkyl group Rb _2, Rb ₃ and Ra ₁ is preferably an alkyl group having 1 to 7 carbon atoms, such as methyl group, ethyl group, n- propyl group, an isopropyl group, n- butyl group, t- butyl group Can be mentioned. The alkyl group of Rb ₂ , Rb ₃ and Ra ₁ may be substituted with a fluorine atom, a hydroxyl group or the like.
Examples of the monocyclic structure formed by combining Rb ₂ and Rb ₃ include a 5- to 8-membered ring.
In the general formulas (Bb-1a-1) and (Bb-1b), in the monocyclic structure, 1 to 3 hydrogen atoms may be substituted with an organic group such as an alkyl group or an alkoxy group.

  Hereinafter, although the preferable specific example of the repeating unit represented by general formula (Bb-1a) is shown, this invention is not limited to this.

  Hereinafter, although the preferable specific example of the repeating unit represented by general formula (Bb-1b) is shown, this invention is not limited to this.

(Bb-2) a repeating unit having an acid-decomposable group and having an acyclic hydrocarbon structure in the group capable of leaving by the action of an acid of the acid-decomposable group In the repeating unit (Bb-2), The non-cyclic hydrocarbon structure is a hydrocarbon structure that does not include a cyclic hydrocarbon structure, and is preferably a chain hydrocarbon structure, and the chain hydrocarbon structure is preferably one having 4 to 10 carbon atoms.

  The repeating unit (Bb-2) is preferably a repeating unit represented by the following general formula (Bb-2a).

In the general formula (Bb-2a),
Rx represents a hydrogen atom or an alkyl group.
Ra ₁ ′, Ra ₂ ′ and Ra ₃ ′ each independently represents an alkyl group.

In the general formula (Bb-2a), Rx is the same as Rx in the general formula (Bb-1a).
The alkyl group of Ra ₁ ′, Ra ₂ ′ and Ra ₃ ′ is preferably an alkyl group having 1 to 7 carbon atoms. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t- A butyl group etc. can be mentioned. The alkyl group of Ra ₁ ′, Ra ₂ ′ and Ra ₃ ′ may be substituted with a fluorine atom, a hydroxyl group or the like.

  Hereinafter, although the preferable specific example of the repeating unit represented by general formula (Bb-2a) is shown, this invention is not limited to this.

The resin of component (B) may have other repeating units in addition to the repeating unit (Ba) and the repeating unit (Bb).
As the other repeating unit that the resin of the component (B) may have, preferably the repeating unit (Ba-1), other acid-decomposable repeating units other than the repeating unit (Bb), and a repeating unit having a lactone group , A repeating unit having an alicyclic hydrocarbon structure substituted with a polar group, a repeating unit having an alkali-soluble group, and the like.

The repeating unit having another acid-decomposable group is preferably a repeating unit having a polycyclic hydrocarbon group, and includes a portion containing an alicyclic hydrocarbon represented by the following general formula (pI) to general formula (pV) More preferred is at least one selected from repeating units in which an alkali-soluble group is protected by a group having a structure.

In general formulas (pI) to (pV),
R ₁₁ represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or a sec-butyl group, and Z forms a polycyclic cyclic hydrocarbon group together with a carbon atom. Represents the atomic group necessary for.
R _{12 to} R ₁₆ each independently represents a linear or branched alkyl group or cycloalkyl group having 1 to 4 carbon atoms. However, at least one of R _{12 to} R ₁₄ , or any of R ₁₅ and R ₁₆ represents a polycyclic cyclic hydrocarbon group.
R _{17 to} R ₂₁ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a cycloalkyl group. However, at least one of R _{17 to} R ₂₁ represents a polycyclic hydrocarbon group. Further, either R ₁₉ or R ₂₁ represents a linear or branched alkyl group or cycloalkyl group having 1 to 4 carbon atoms.
R _{22 to} R ₂₅ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a cycloalkyl group. However, at least one of R _{22 to} R ₂₅ represents a polycyclic cyclic hydrocarbon 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 _{12 to} R ₂₅ represents a linear or branched alkyl group having 1 to 4 carbon atoms, for example, methyl group, ethyl group, propyl Groups and the like.

The cycloalkyl group in R _{12 to} R ₂₅ 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. These cycloalkyl groups may have a substituent.

  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.

The polycyclic cyclic hydrocarbon group represented by R _{12 to} R ₂₅ or the polycyclic cyclic hydrocarbon group formed by Z and a carbon atom is a bicyclo, tricyclo or tetracyclo structure having 7 or more carbon atoms among the above cycloalkyl groups. And the like. The number of carbon atoms is preferably 7 to 30, and particularly preferably 7 to 25 carbon atoms. These polycyclic cyclic hydrocarbon groups may have a substituent.

Preferred examples of the polycyclic hydrocarbon group include an adamantyl group, a noradamantyl group, a decalin residue, a tricyclodecanyl group, a tetracyclododecanyl group, a norbornyl group, and a cedrol group. More preferred examples include an adamantyl group, norbornyl group, tetracyclododecanyl group, and tricyclodecanyl group.

  As further substituents of these 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 (carbon numbers) 2-6). 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.

  The structures represented by the general formulas (pI) to (pV) in the resin are used for protecting alkali-soluble groups. Specific examples include a structure in which a hydrogen atom of a carboxylic acid group, a sulfonic acid group, a phenol group, or a thiol group is substituted with a structure represented by the general formulas (pI) to (pV), preferably a carboxylic acid Group, a hydrogen atom of a sulfonic acid group is substituted with a structure represented by general formulas (pI) to (pV).

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

Here, R represents a hydrogen atom, a halogen atom, or a linear or branched alkyl group having 1 to 4 carbon atoms. The alkyl group of R may be substituted with a halogen atom, a hydroxyl group or the like. 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 is preferable.
Rp ₃ represents any one group of formulas (pI) ~ (pV).

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

  Specific examples of the repeating unit represented by the general formula (pA) are shown below.

In the above specific examples, Rx represents a hydrogen atom or an alkyl group. Rx is preferably a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.
Rxa and Rxb each independently represent a linear or branched alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, and a hetero atom such as oxygen or sulfur in the alkyl chain or cycloalkyl chain May be included.
The alicyclic hydrocarbon skeleton may have a substituent.

The resin of component (B) preferably 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. These lactone groups are preferably linked to the polymer main chain with a non-acid-decomposable bond. That is, the repeating unit having a lactone group is preferably a non-acid-decomposable repeating unit. Here, the non-acid-decomposable means a group that has no or very low reactivity due to the action of an acid in a process in which the positive photosensitive composition of the present invention is usually used and substantially contributes to image formation by an acid. It is not to have. As the non-acid-decomposable bond, a primary or secondary ester bond is preferable. The primary or secondary ester bond has no or very little reactivity due to the action of an acid in a process in which the positive photosensitive composition of the present invention is usually used.
Preferred lactone structures are (LC1-1) (LC1-4) (LC1-5) (LC1-6) (LC1-13) (LC1-14). By using a specific lactone structure, line edge roughness, 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. n ₂ represents an integer of 0-4. When n ₂ is 2 or more, a plurality of Rb ₂ may be the same or different, and a plurality of Rb ₂ may be bonded to form a ring.

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

In general formula (AI),
R _b0 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms.
Preferable substituents that the alkyl group for R _b0 may have include a hydroxyl group and a halogen atom.
Examples of the halogen atom for R _b0 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
R _b0 is preferably a hydrogen atom or a methyl group.
A _b is an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, a single bond, an ether group, an ester group, a carbonyl group, a carboxyl group, or a divalent group obtained by combining these. Represents. Preferably a single bond, -Ab ₁ -CO ₂ - is a 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.

  In the above specific examples, Rx represents a hydrogen atom or an alkyl group. Rx is preferably a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.

  The resin as the component (B) preferably has a repeating unit having an alicyclic hydrocarbon structure substituted with a polar group. This improves the substrate adhesion and developer compatibility. The polar group is preferably a hydroxyl group or a cyano group. Preferred is a repeating unit having a partial structure represented by the following general formula (VIIa) or (VIIb), and more preferred is a repeating unit represented by the following general formula (AIIa) or (AIIb).

In general formula (VIIa),
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 hydroxyl groups and the rest are hydrogen atoms, more preferably two of R _{2c to} R _4c are hydroxyl groups and the rest are hydrogen atoms.

In the general formulas (AIIa) and (AIIb),
R _1c represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.

  Specific examples of the repeating unit having the structure represented by the general formula (VIIa) or (VIIb) are shown below, but the present invention is not limited thereto.

  The resin of component (B) preferably has a repeating unit having an alkali-soluble group, and more preferably has a repeating unit having a carboxyl group. By having this, the resolution in contact hole applications increases. The repeating unit having a carboxyl group includes a repeating unit in which a carboxyl group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or a carboxyl group in the main chain of the resin through a linking group. Either a repeating unit that is bonded, or a polymerization initiator or chain transfer agent having an alkali-soluble group is introduced at the end of the polymer chain at the time of polymerization, and the linking group is a monocyclic or polycyclic hydrocarbon. You may have a structure. Most preferred are acrylic acid and methacrylic acid.

  The resin of the component (B) may further have a repeating unit having 1 to 3 groups represented by the following general formula (F1). This improves line edge roughness performance.

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.
Ra represents a hydrogen atom or an organic group (preferably an acid-decomposable protecting group, an alkyl group, a cycloalkyl group, an acyl group, or an alkoxycarbonyl group).

The alkyl group of R _{50 to} R ₅₅ may be substituted with a halogen atom such as a fluorine atom, a cyano group, etc., preferably an alkyl group having 1 to 3 carbon atoms, such as a methyl group or a trifluoromethyl group. be able to.
R _{50 to} R ₅₅ are preferably all fluorine atoms.

  As the organic group represented by Ra, an acid-decomposable protective group, which may have a substituent, an alkyl group, a cycloalkyl group, an acyl group, an alkylcarbonyl group, an alkoxycarbonyl group, an alkoxycarbonylmethyl group, an alkoxymethyl group , 1-alkoxyethyl group is preferable.

  The repeating unit having the general formula (F1) is preferably a repeating unit represented by the following general formula (F2).

In general formula (F2),
Rxc represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms. Preferable substituents that the alkyl group of Rxc may have include a hydroxyl group and a halogen atom.
Fa represents a single bond or a linear or branched alkylene group (preferably a single bond).
Fb represents a monocyclic or polycyclic hydrocarbon group.
Fc represents a single bond or a linear or branched alkylene group (preferably a single bond or a methylene group).
F ₁ represents a group represented by the general formula (F1).
P ₁ represents a 1 to 3.

  As the cyclic hydrocarbon group for Fb, a cyclopentyl group, a cyclohexyl group, and a norbornyl group are preferable.

  Specific examples of the repeating unit having the structure of the general formula (F1) are shown.

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

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

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

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

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

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

As a preferred embodiment of the resin of component (B), all the repeating units have (meth) acrylate repeating units, and all the repeating units are methacrylate repeating units, or all the repeating units are acrylate repeating units. And any resin containing both methacrylate repeating units and acrylate repeating units. When both the methacrylate repeating unit and the acrylate repeating unit are included, the repeating unit having a polar functional group is preferably an acrylate.

  In the resin of component (B), the content of the repeating unit having an acid-decomposable group is preferably 10 to 60 mol%, more preferably 20 to 50 mol%, still more preferably 25 to 40 mol in all repeating structural units. %.

In the resin (B), the content of the repeating unit (Ba-1) is preferably 20 to 50 mol% in all the repeating units.
In the resin of component (B), the content of the repeating unit (Ba-2) is preferably 5 to 30 mol% in all the repeating units.
In the resin of the component (B), the content of the repeating unit (Bb) is preferably 10 to 60 mol%, more preferably 20 to 50 mol%, still more preferably 25 to 40 mol% in all repeating units. is there.
In the resin of component (B), the ratio of the repeating unit (Bb) to the entire repeating unit having an acid-decomposable group is preferably 20 to 100 mol%, more preferably 30 to 80 mol%, still more preferably 40. -70 mol%.

When the positive photosensitive composition of the present invention is for ArF exposure, the resin of the component (B) preferably has no aromatic group from the viewpoint of transparency to ArF light.
(B) As a preferable aspect of resin of a component, 20-50 mol% of repeating units (Ba-1), repeating unit (Bb), or the repeating unit which has another acid-decomposable group, 20-20 mol% of repeating units which have a lactone structure A terpolymer having 50 mol%, 5 to 30 mol% of a repeating unit having a diamantane structure substituted with a polar functional group or another alicyclic hydrocarbon structure substituted with a polar group, and further It is a quaternary copolymer containing 0 to 20 mol% of other repeating units.
Another preferred embodiment of the resin of component (B) is a repeating unit (Ba-2) of 5 to 30 mol%, a repeating unit (Ba-1), a repeating unit (Bb) or a repeating group having other acid-decomposable groups. Examples include terpolymers having 20 to 50 mol% of units, 20 to 50 mol% of repeating units having a lactone group, and quaternary copolymers having 0 to 20 mol% of other repeating units. it can.
The resin of component (B) preferably further has a repeating unit having an adamantane structure. As the repeating unit having an adamantane structure, for example, in the repeating unit represented by the general formula (PA), Rp _{3 in} the formula is represented by the repeating unit having an adamantane structure and the general formula (AIIa). Mention may be made of repeating units.

The resin of component (B) can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and the polymerization is performed by heating, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. As a monomer addition method in the dropping polymerization method, only a solvent is charged into a reaction vessel and a monomer solution is dropped into this solution, or a part of monomer species is first charged in a reaction vessel in advance and the remaining is left. Any method may be used which is added dropwise. The polymerization initiator may be added in the same solution as the monomer, or may be added from a solution different from the monomer solution. When the polymerization initiator is added from a solution different from the monomer solution, the dropping speed of the monomer solution and the initiator solution may be the same or different. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the 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, the generation of particles during storage can be suppressed.
The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. If desired, an initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery. The concentration of the reaction is 5 to 50% by mass, preferably 10 to 30% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.

The weight average molecular weight of the resin of component (B) is preferably 3000 to 30000, more preferably 5000 to 15000, and still more preferably 6000 to 12000 as a polystyrene-converted value by the GPC method. By adjusting the molecular weight to an appropriate range, exposure latitude, development defects, scum generation, line edge roughness, and the like can be improved.
The weight average molecular weight is determined by appropriately selecting the type of polymerization initiator, the amount of polymerization initiator, the chain transfer agent, the polymerization temperature, the reaction solvent, the concentration of the reaction solution, and the polymerization method (drop polymerization, batch polymerization, etc.) in the polymerization reaction. Can be adjusted.

The dispersity (Mw / Mn) of the component (B) resin is preferably 1.1 to 3.0, more preferably 1.2 to 2.5, and even more preferably 1.4 to 2.1. It is. 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 order to adjust the degree of dispersion, for example, a living radical polymerization method can be used to obtain a resin having a degree of dispersion of 1.0 to 1.5. In addition, a resin having a relatively wide dispersion obtained by polymerization is removed by using a reprecipitation method, a solvent washing method, etc., to remove a low molecular weight component, a high molecular weight component, or both using a difference in solubility of the resin in a solvent. By doing so, a resin with a narrow dispersion degree can be obtained.

In the positive photosensitive composition of the present invention, the blending amount of the resin as the component (B) in the entire composition is preferably 50 to 99.99% by mass, more preferably 60 to 99.0% by mass in the total solid content. %.
In the present invention, the resin of component (B) may be used alone or in combination.

(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 referred to as “resin of component (B2)”. May be included).
“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 decomposes by the action of an alkali and improves the solubility in an alkali developer.

  As the resin of the component (B2), for example, a resin having at least one repeating unit derived from a (meth) acrylic acid derivative and / or an alicyclic olefin derivative is preferable.

Examples of the alkali-soluble group in the component (B2) resin include, for example, 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 electron-withdrawing group. An amino 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) Group, methine group).
The group that decomposes by the action of alkali in the resin of component (B2) and increases the solubility in an alkaline developer is preferably, for example, a lactone group or an acid anhydride group, more preferably a lactone group. .

The resin as the component (B2) may further have a repeating unit having a functional group other than those described above. As the repeating unit having another functional group, a repeating unit having an appropriate functional group can be selected in consideration of dry etching resistance, hydrophilicity / hydrophobicity, interaction property and the like.
Examples of the repeating unit having another functional group include a repeating unit having a polar functional group such as a hydroxyl group, a cyano group, a carbonyl group, and an ester group, a repeating unit having a monocyclic or polycyclic hydrocarbon structure, and a fluoroalkyl group. And a repeating unit having a plurality of these functional groups.

  The weight average molecular weight of the resin of component (B2) is preferably 3000 to 30000, more preferably 5000 to 15000, and still more preferably 6000 to 12000 as a polystyrene-converted value by the GPC method.

  Although the preferable specific example of resin of (B2) component is shown below, this invention is not limited to this.

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

[3] (C) A dissolution inhibiting compound having a molecular weight of 3000 or less, which decomposes by the action of an acid to increase the solubility in an alkaline developer. The positive photosensitive composition of the present invention is decomposed by the action of an acid to form an alkali. It can contain a dissolution inhibiting compound having a molecular weight of 3000 or less (hereinafter referred to as “dissolution inhibiting compound”) that increases the solubility in the developer.
The dissolution inhibiting compound has an acid-decomposable group such as a cholic acid derivative containing an acid-decomposable group described in Proceeding of SPIE, 2724,355 (1996) so as not to lower the permeability of 220 nm or less. Alicyclic or aliphatic compounds are preferred. Examples of the acid-decomposable group and alicyclic structure are the same as those described for the component (B) resin.

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

  The addition amount of the dissolution inhibiting compound is preferably 3 to 50% by mass, more preferably 5 to 40% by mass, based on the solid content of the positive photosensitive composition.

  Specific examples of the dissolution inhibiting 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 compounds include compounds having partial structures represented by the following general formulas (A) to (E).

In general formula (A),
R ²⁵⁰ , R ²⁵¹ and R ²⁵² are each independently a hydrogen atom, an alkyl having 1 to 20 carbons, a cycloalkyl group having 3 to 20 carbons or an aryl group having 6 to 20 carbons, wherein R ²⁵⁰ And R ²⁵¹ may combine with 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, benzimidazole, and the like. 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. 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) sulfonium. Examples thereof include hydroxide, bis (t-butylphenyl) iodonium hydroxide, phenacylthiophenium hydroxide, and 2-oxopropylthiophenium hydroxide. The compound having an onium carboxylate structure is a compound having an onium hydroxide structure in which the anion moiety is converted to a carboxylate, and examples thereof include acetate, adamantane-1-carboxylate, and perfluoroalkylcarboxylate. 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) Surfactant The positive photosensitive composition of the present invention preferably further contains a surfactant, and a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant, silicon It is more preferable to contain any one of a system surfactant and a surfactant having both a fluorine atom and a silicon atom, or two or more thereof.

  The positive photosensitive composition of the present invention contains fluorine and / or a silicon-based surfactant, so that adhesion and development can be achieved 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 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 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.), 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. In addition, poly (oxyalkylene) groups include poly (oxyethylene) groups, poly (oxyethylene) groups,
Oxypropylene) group, poly (oxybutylene) group, etc., and the same such as poly (block connection body of oxyethylene, oxypropylene and oxyethylene) and poly (block connection body of oxyethylene and oxypropylene) It may be a unit having different chain length alkylenes in the chain length. 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.

  In the present invention, other surfactants other than the fluorine-based and / or silicon-based surfactants can be used. Specifically, nonionic interfaces such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan aliphatic esters, polyoxyethylene sorbitan aliphatic esters, etc. Activators can be used.

  The amount of the 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.
Solvents that can be used include, for example, 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 possessed by 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 having a hydroxyl group and a solvent having no hydroxyl group.
(S2) A mixed solvent in which a solvent having an ester structure and a solvent having a ketone structure are mixed.
(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 having a hydroxyl group.
(S5) A mixed solvent obtained by mixing a solvent having an ester structure, a solvent having a carbonate structure, and a solvent having 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 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 preferred.

  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. Among these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are preferable, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate 2-heptanone and cyclohexanone are more 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, and propylene carbonate is preferred.

The mixing ratio (mass) of the solvent having a hydroxyl group and the solvent having no hydroxyl group is from 1/99 to 99/1, preferably from 10/90 to 90/10, more preferably from 20/80 to 60/40. . A mixed solvent containing 50% by mass or more of a solvent having no hydroxyl group 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 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 having a hydroxyl group, the solvent having an ester structure is 30 to 80% by weight, the solvent having a lactone structure is 1 to 20% by weight, and the solvent having a hydroxyl group It is preferable to contain 10 to 60 weight%.
When mixing a solvent having an ester structure, a solvent having a carbonate structure and a solvent having a hydroxyl group, the solvent having an ester structure is 30 to 80% by weight, the solvent having a carbonate structure is 1 to 20% by weight, and the solvent having a hydroxyl group It is preferable to contain 10 to 60 weight%.

A more preferable embodiment of the solvent 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 selected from a functional group selected from a hydroxyl group, a ketone group, a lactone group, an ester group, an ether group, and a carbonate group, or a solvent having a plurality of these functional groups. Is more preferable. A particularly preferred 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 a particularly preferable mixed solvent.
The mixing ratio (mass ratio) of the alkylene glycol monoalkyl ether carboxylate and the other solvent is alkylene glycol monoalkyl ether carboxylate / other solvent = 95/5 to 30/70, more preferably 95/5 to 40. / 60, more preferably 80/20 to 50/50. By increasing the ratio of the alkylene glycol monoalkyl ether carboxylate, it is possible to reduce the change in performance over time until the exposure after coating.

  The solid content concentration in the positive photosensitive composition of the present invention is preferably 3 to 15% by mass, more preferably 4 to 10% by mass, and still more preferably 5 to 8% by mass.

<Other additives>
If necessary, the positive photosensitive composition of the present invention may further contain a dye, a plasticizer, a photosensitizer, a compound that promotes solubility in a developer, and the like.

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

  A preferable addition amount of these dissolution promoting compounds is 2 to 50% by mass, and more preferably 5 to 30% by mass with respect to the resin of the component (B). The amount is preferably 50% by mass or less from the viewpoint of suppressing development residue and preventing pattern deformation during 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 219294, and the like. 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.

(Pattern formation method)
The positive photosensitive composition of the present invention is used by dissolving the above components 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 film thickness of the formed photosensitive film is preferably 50 to 300 nm, more preferably 70 to 200 nm, still more preferably 80 to 150 nm. The effect of the positive photosensitive composition of the present invention is remarkably exhibited at a thinner film thickness.
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, this invention is not limited to this.

Synthesis Example 1 (Synthesis of monomer (A))
9.8 g of hydroxydiamantane, 3.7 g of methacrylic anhydride and 0.5 g of concentrated sulfuric acid were dissolved in 150 ml of toluene, and this was reacted under reflux conditions for 2 hours. The reaction solution was washed with an aqueous sodium bicarbonate solution and then with distilled water, dried over anhydrous sodium sulfate and concentrated to obtain a crude product. When this was purified by column chromatography, 6.3 g of monomer (A) was obtained.

Synthesis Example 2 (Synthesis of monomer (B))
160 ml of bromine was cooled to −7 ° C., and 40 g of diamantane was gradually added thereto while keeping the temperature of the reaction solution at −3 ° C. or lower. Thereafter, 2.16 g of aluminum bromide was gradually added while keeping the temperature of the reaction solution at 0 ° C. or lower. The mixture was stirred at -7 ° C for 30 minutes, and the reaction solution was slowly poured into a solution of 500 g of sodium sulfite, 160 g of sodium hydroxide and 3 L of water. The precipitate was collected by filtration and washed with acetonitrile to obtain 63 g of dibromodiamantane.
To 20 g of dibromodiamantane, 80 ml of concentrated nitric acid was slowly added, and this was heated to 70 ° C. and reacted for 30 minutes. The reaction solution was poured into 300 ml of water to make it alkaline by adding 72 g of sodium hydroxide / 500 ml of water. The precipitate was collected by filtration and washed with water to obtain 7 g of dihydroxydiamantane.
2 g of monomer (B) was obtained in the same manner as the synthesis of monomer (A) using dihydroxydiamantane.

Synthesis Example 3 (Synthesis of resin (RA-1))
Under a nitrogen stream, 5.6 g of propylene glycol monomethyl ether acetate and 3.8 g of propylene glycol monomethyl ether were placed in a three-necked flask and heated to 80 ° C. To this, 2.7 g of monomer (A), 4.7 g of 3-hydroxyadamantane methacrylate, 5.5 g of 1-ethyl-1-cyclopentyl methacrylate, 6.8 g of γ-butyrolactone methacrylate, polymerization initiator V-601 (Wako Pure Chemical Industries, Ltd.) Made by dissolving 6 mol% of the product in 42.6 g of propylene glycol monomethyl ether acetate and 28.4 g of propylene glycol monomethyl ether with respect to the monomer 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 poured into 720 ml of hexane / 80 ml of ethyl acetate, and the precipitated powder was collected by filtration and dried to obtain 18 g of Resin (RA-1). The weight average molecular weight of the obtained resin was 7200, and the dispersity (Mw / Mn) was 1.90.

Synthesis Example 4 (Synthesis of resin (RA-2))
Under a nitrogen stream, 8.9 g of cyclohexanone was placed in a three-necked flask and heated to 80 ° C. To this, 2.9 g of monomer (B), 4.4 g of norbornane lactone methacrylate, 3.4 g of 2- (4-methylcyclohexyl) propyl-2-methacrylate, 0.4 g of methacrylic acid, polymerization initiator V-601 (Wako Pure Chemical Industries, Ltd.) A product obtained by dissolving 9 mol% of a drug product in 40 g of cyclohexanone with respect to the monomer was dropped 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 poured into 315 ml of hexane / 135 ml of ethyl acetate, and the precipitated powder was collected by filtration and dried to obtain 10.2 g of resin (RA-2). The weight average molecular weight of the obtained resin was 6900, and the dispersity (Mw / Mn) was 1.74.

  The structures, molar ratios, weight average molecular weights, and dispersities of resins (RA-1) to (RA-18) and comparative resins (RA′-1) to (RA′-3) are shown below.

Examples 1-21 and Comparative Examples 1-3
<Resist preparation>
The components shown in Table 1 below were dissolved in a solvent to prepare a solution having a solid content of 9% by mass.
A positive resist solution was prepared by filtration through a 03 m polyethylene filter. The prepared positive resist solution was evaluated by the following method, and the results are also shown in Table 1.

Hereinafter, abbreviations in the table are shown.
[Basic compounds]
TPI: 2,4,5-triphenylimidazole TPSA: triphenylsulfonium acetate DIA: 2,6-diisopropylaniline DCMA: dicyclohexylmethylamine TPA: tripentylamine HAP: hydroxyantipyrine TBAH: tetrabutylammonium hydroxide TMEA: Tris ( Methoxyethoxyethyl) amine PEA: N-phenyldiethanolamine [Surfactant]
W-1: MegaFuck F176 (Dainippon Ink Chemical Co., Ltd.) (Fluorine)
W-2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.) (fluorine and silicon)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) (silicon-based)

W-4: Troisol S-366 (manufactured by Troy Chemical Co., Ltd.)
〔solvent〕
S1: Propylene glycol methyl ether acetate S2: 2-heptanone S3: Cyclohexanone S4: γ-butyrolactone S5: Propylene glycol methyl ether S6: Ethyl lactate S7: Propylene carbonate

<Resist evaluation>
An antireflection film DUV-42 manufactured by Brewer Science Co., Ltd. was uniformly applied to 600 Å 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 with a spin coater and dried at 110 ° C. for 90 seconds to form a 180 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.

Density dependency evaluation method:
The exposure amount that reproduces the 80 nm line and space 1: 1 mask pattern is the optimum exposure amount, and the finished line when an isolated line pattern (line and space = 1/10) mask with a line width of 125 nm is exposed at the optimum exposure amount. The width was observed. The thicker the finished line width (the larger the value), the smaller the line width of the isolated pattern and the better the density dependency.

  From Table 1, it is clear that the positive photosensitive composition of the present invention is excellent in density dependency.

(Immersion exposure)
<Resist preparation>
The components of Examples 1 to 21 and Comparative Examples 1 to 3 in Table 1 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 obtain a positive resist solution. Prepared. The prepared positive resist solution was evaluated by the following method.
<Resolution evaluation>
An organic antireflection film ARC29A (Nissan Chemical Co., Ltd.) was applied on a silicon wafer and baked at 205 ° C. for 60 seconds to form a 78 nm antireflection film. Each positive resist solution was applied thereon 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 exposure, the resist pattern obtained by heating at 115 ° C. for 90 seconds, developing with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 60 seconds, rinsing with pure water, and spin drying is then used for the scanning pattern. It observed using the electron microscope (Hitachi S-9260). When the positive resist solutions of Examples 1 to 21 were used, the 65 nm line and space pattern was resolved without causing pattern collapse. On the other hand, when the positive resist solutions of Comparative Examples 1 to 3 were used, the pattern collapse was observed in some patterns although the 65 nm line and space pattern was resolved.
It is clear that the positive photosensitive composition of the present invention has a good image forming ability even in an exposure method using an immersion liquid.

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

Explanation of symbols

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

Claims (5)

(A) A positive photosensitive composition comprising a compound that generates an acid upon irradiation with actinic rays or radiation, and (B) a resin having a group that decomposes by the action of the acid and increases the solubility in an alkali developer. There,
The resin of component (B) has a repeating unit (Ba) having a diamantane structure and a group that decomposes by the action of an acid and increases the solubility in an alkali developer, and decomposes by the action of the acid, A positive photosensitive resin characterized in that it is a resin having a repeating unit (Bb) having a non-polycyclic hydrocarbon structure in a group that is eliminated by the action of an acid of a group that increases the solubility in a developer. Composition. A group having a group that decomposes by the action of an acid and increases the solubility in an alkali developer, and that is decomposed by the action of the acid and that is released by the action of an acid of a group that increases the solubility in an alkali developer. The repeating unit (Bb) having a non-polycyclic hydrocarbon structure is at least one repeating unit selected from the following general formulas (Bb-1a), (Bb-1b) and (Bb-2a) The positive photosensitive composition according to claim 1.

In the general formula (Bb-1a),
Rx represents a hydrogen atom or an alkyl group.
Rb ₁ represents a monocyclic hydrocarbon group represented by the following general formula (Bb-1a-1).
Rb ₂ and Rb ₃ each independently represent an alkyl group, a monocyclic cyclic hydrocarbon group represented by the general formula (Bb-1a-1), or an allyl group. Rb ₂ and Rb ₃ may combine with each other to form a monocyclic hydrocarbon structure.

In the general formula (Bb-1a-1),
n represents an integer of 1 to 4.

In general formulas (Bb-1b) and (Bb-2a),
Rx represents a hydrogen atom or an alkyl group.
Ra ₁ represents an alkyl group or an allyl group.
n represents an integer of 1 to 4.
Ra ₁ ′, Ra ₂ ′ and Ra ₃ ′ each independently represents an alkyl group.   The positive photosensitive material according to claim 1 or 2, wherein the repeating unit (Ba) having a diamantane structure is a repeating unit having a diamantane structure and not affected by the action of an acid or an alkali. Composition.   The positive photosensitive composition according to claim 1, wherein the resin as the component (B) further has a repeating unit having an adamantane structure.   A pattern forming method comprising the steps of: forming a photosensitive film from the positive photosensitive composition according to claim 1; and exposing and developing the photosensitive film.

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